Language：English   Publishing type：Research paper (scientific journal)  

Three novel analogs of pochonicine (1) were isolated from a solid fermentation culture of the fungal strain Pochonia suchlasporia var. suchlasporia TAMA 87, and their structures were elucidated as 7-deoxypochonicine (2), 6-deoxypochonicine (3), and 6,7-dideoxypochonicine (4). These analogs were found to possess the same stereochemistry as pochonicine. Comparison of β-N-acetylglucosaminidase (GlcNAcase) inhibitory activity between these analogs and pochonicine suggested that the C-6 hydroxy group of pochonicine was essential to its potent GlcNAcase inhibitory activity and that the C-7 hydroxy group also contributed to the activity, but to a lesser extent than the C-6 hydroxy group.

DOI： 10.1584/jpestics.D20-086

PubMed

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Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.lwt.2020.110061

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Authorship：Lead author,　Corresponding author  

J-GLOBAL

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Language：English   Publishing type：Research paper (scientific journal)  

A new asteltoxin analog, named asteltoxin H (1), was isolated by the solid-state fermentation of the fungus Pochonia suchlasporia var. suchlasporia TAMA 87. The chemical structure of 1 was deduced by spectroscopic methods, including 1D and 2D NMR, HRESIMS, and UV-Vis analyses. Compound 1 showed insecticidal activity against prepupae of the blowfly, Lucilia sericata, with an LD50 value of 0.94 µg/mg prepupal body weight.

DOI： 10.1584/jpestics.D19-081

PubMed

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Language：English   Publishing type：Research paper (scientific journal)  

A tannase-encoding gene, AotanB, from Aspergillus oryzae RIB40 was overexpressed in A. oryzae AOK11 niaD-deficient mutant derived from an industrial strain under the control of an improved glucoamylase gene promoter PglaA142. The recombinant tannase, designated as rAoTanBO, was produced efficiently as an active extracellular enzyme. Purified rAoTanBO showed a smeared band with a molecular mass of approximately 80-100 kDa on sodium dodecyl sulfate polyacrylamide gel electrophoresis. The rAoTanBO had a molecular mass of 65 kDa, after treatment with endo-β-N-acetylglucosaminidase H. Purified rAoTanBO exhibited maximum activity at 30-35°C and pH 6.0. The tannase activity of purified rAoTanBO towards natural and artificial substrates was 2-8 folds higher than that of the recombinant enzyme produced by Pichia pastoris, designated as rAoTanBP. N-terminus of the mature rAoTanBP had six more amino acids than the N-terminus of the mature rAoTanBO. Kinetic analyses showed that rAoTanBO had higher catalytic efficiency (kcat/Km) than rAoTanBP. rAoTanBO was stable up to 60°C and higher thermostability than rAoTanBP. N-linked oligosaccharides had no effect on the activity and stability of rAoTanBO and rAoTanBP.

DOI： 10.1016/j.jbiosc.2019.08.002

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Authorship：Last author   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.aquaculture.2019.02.040

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Biotransformation of β-mangostin (1) by the endophytic fungus Xylaria feejeensis GM06 afforded hexacyclic ring-fused xanthenes with an unprecedented hexacyclic heterocylic skeleton. β-Mangostin (1) was transformed to two diastereomeric pairs of enantiomers, mangostafeejin A [(-)-2a/(+)-2b)] and mangostafeejin B [(-)-3a/(+)-3b)]. The chemical structures of the transformation products were elucidated by analysis of NMR and MS data, and the structure of mangostafeejin A [(-)-2a/(+)-2b)] was confirmed by single-crystal X-ray diffraction analysis. The absolute configurations of 3a and 3b were established on the basis of calculated and measured ECD data using the ECD spectra of 2a and 2b as models. The fungal biotransformation described herein provides an effective method to convert an abundant achiral plant natural product scaffold into new chiral heterocyclic scaffolds representing expanded chemical diversity for biological activity screening.

DOI： 10.1021/acs.jnatprod.8b00519

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Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier B.V.  

This study aimed to produce inexpensive 5-aminolevulinic acid (ALA) in a non-sterile latex rubber sheet wastewater (RSW) by Rhodopseudomonas palustris TN114 and PP803 for the possibility to use in agricultural purposes by investigating the optimum conditions, and applying of wood vinegar (WV) as an economical source of levulinic acid to enhance ALA content. The Box–Behnken Design experiment was conducted under microaerobic-light conditions for 96 h with TN114, PP803 and their mixed culture (1:1) by varying initial pH, inoculum size (% v/v) and initial chemical oxygen demand (COD, mg/L). Results showed that the optimal condition (pH, % inoculum size, COD) of each set to produce extracellular ALA was found at 7.50, 6.00, 2000 for TN114
7.50, 7.00, 3000 for PP803
and 7.50, 6.00, 4000 for a mixed culture
and each set achieved COD reduction as high as 63%, 71% and 75%, respectively. Addition of the optimal concentration of WV at mid log phase at 0.63% for TN114, and 1.25% for PP803 and the mixed culture significantly increased the ALA content by 3.7–4.2 times (128, 90 and 131 μM, respectively) compared to their controls. ALA production cost could be reduced approximately 31 times with WV on the basis of the amount of levulinic acid used. Effluent containing ALA for using in agriculture could be achieved by treating the RSW with the selected ALA producer R. palustris strains under the optimized condition with a little WV additive.

DOI： 10.1016/j.sjbs.2016.01.028

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier B.V.  

Single cell protein (SCP) is an alternative way to increase nutrients for animal consumption
and purple nonsulfur bacteria (PNSB) should be considered as SCP due to their rich sources of protein, vitamins and photopigments. Hence, the aim of this study was to investigate the potential of promising PNSB to be used as SCP by mixing with commercial shrimp feed for white shrimp cultivation starting from postlarval until early juvenile stages for 60 days. PNSB strains, Rhodobacter sphaeroides SS15 and Afifella marina STW181 were selected, based on high amounts of biologically complete protein and photopigments, to use as SCP at a ratio of 1:1
and their lyophilized cells at 1, 3 and 5% (w/w) were mixed well with commercial shrimp feed to obtain modified shrimp feed recipes
Diet 1, Diet 2 and Diet 3, respectively. Levels of NH4 +, NO2 −, NO3 − and COD in rearing water from Diet 2 and 3 sets were significantly higher than control set. However, Diet 1 set showed the lowest levels of these water parameters among modified diet sets as no significant difference levels of NO3 − and COD between Diet 1 and control sets. Shrimp growth performance on the basis of relative gain rate and other growth parameters found that Diet 1 set was much better than sets of Diet 2, Diet 3 and control with the lowest found in the control set. In addition, the maximum shrimp survival was observed in Diet 1 set (85%) although no significant difference among them as 80% in control set. No significant difference was found among control and all modified shrimp diets for total hemocyte count in shrimp
however, significant increases of superoxide dismutase activity found in sets of Diet 1, while phenoloxidase activity found in Diet 2 and Diet 3. The results of hepatopancreas (HP) histopathology analysis also showed a good condition of HP as healthy shrimp. PNSB biomass as SCP at optimal level has the potential to be an effective source of a novel protein in shrimp feed to enhance shrimp growth and also to increase shrimp survival as more nutritious with no effect on water quality.

DOI： 10.1016/j.aquaculture.2018.02.009

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society for Bioscience Biotechnology and Agrochemistry  

A co-cultivation study of two fungal strains showed that Aspergillus ustus could inhibit Aspergillus repens growth. The bioactive compound responsible for the observed activity was purified and identified as a sesterterpene, ophiobolin K. Ophiobolin K exhibited marked inhibition against both fungi and bacteria, especially A. repens, A. glaucus and gram-positive bacteria including Bacillus subtilis, Staphylococcus aureus, and Micrococcus luteus.

DOI： 10.1080/09168451.2018.1429890

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J-GLOBAL

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY  

Shrimp cultivation has been faced with huge losses in productivity caused by infectious shrimp pathogenic vibrios, especially Vibrio parahaemolyticus that causes acute hepatopancreatic necrosis disease (AHPND). Hence, purple nonsulphur bacteria (PNSB) were isolated from shrimp ponds for investigating their abilities to control shrimp pathogenic Vibrio spp. and their use as probiotics for sustainable shrimp cultivation. Based on their probiotic properties, strains S3W10 and SS15 were selected because of their strong abilities to produce amylase, gelatinase and vitamin B12. However, only three PNSB strains (SS15, TKW17 and STW181) strongly inhibited V. harveyi_KSAAHRC and V. vulnificus_KSAAHRC including V. parahaemolyticus AHPND strains by secreting antivibrio compounds. Four selected PNSB also grew in the presence of pancreatic enzymes, and they were identified as Rhodobacter sphaeroides for strains S3W10, SS15 and TKW17 and Afifella marina for strain STW181. The effects of a mixed culture were also investigated as follows: T1 (S3W10 + SS15), T2 (S3W10 + TKW17) and T3 (S3W10 + STW181) on postlarval white shrimp (Litopenaeus vannamei) for 60 days by comparison with a control. All three probiotic PNSB sets significantly improved the digestive enzyme activities and shrimp growth with their proliferation in shrimp gastrointestinal tract although the shrimp survival was not significantly different. They also significantly reduced the cumulative mortality of shrimp exposed to a virulent AHPND strain (V. parahaemolyticus SR2). This is the first to conclude that selected probiotic PNSB strains have great potential to be used for shrimp cultivation to control vibrios including AHPND strains.

DOI： 10.1111/are.13149

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

This study aimed to investigate the potential of a mixed probiotic purple nonsulfur bacteria (PNSB) for controlling water quality and preventing acute hepatopancreatic necrosis disease (AHPND) to promote growth performance and increase survival of white shrimp (Litopenaeus vannamei) in postlarval stage during cultivation. Four probiotic PNSB (Rhodobacter sphaeroides strains SS15, S3W10, TKW17 and Afifella marina STW181) were investigated for controlling water quality using a mixed culture at a ratio of 1: 1 (roughly 1 x 10(8) cells mL(-1) for each, every week 1-7) as follows; T1 (S3W10 + SS15), T2 (S3W10 + TKW17) and T3 (S3W10 + STW181) and found that throughout 8 weeks shrimp cultivation the most effective sets to reduce NH4(+) and promote shrimp growth (based on weight and total length) were T1 and T3, respectively. Hence, PNSB strains (SS15, S3W10 and STW181) were used as a mixed culture (1: 1: 1, roughly 1 x 10(8) cells mL(-1) for each at weeks 1, 2 and 3) assessing their potential to prevent AHPND by challenge test on shrimp with a virulent strain AHPND-causing Vibrio parahaemolyticus SR2 (roughly 1 x 10(5) cells mL(-1) at day 15) during shrimp cultivation for 30 days. Inoculated PNSB sets (positive control: only PNSB inoculation, and treatment: both PNSB and SR2 inoculations) significantly decreased (P < 0.05) the levels of NH4-, NO2-, NO3- and chemical oxygen demand (COD) with significantly higher (P < 0.05) of dissolved oxygen (DO) compared to native control (no inoculation) and challenge test (only SR2 inoculation). The maximal growth performance of shrimp was observed in the positive control; while no significant difference (P > 0.05) was observed for other sets. PNSB survived and colonized in intestinal shrimp tract to prevent AHPND by increasing 11% survival rate of infected shrimp by strain SR2. The correlation coefficient between PNSB population and shrimp survival showed a positive strong correlation, but a negative strong correlation between vibrios population and shrimp survival. Overall results proved that a mixed three probiotic PNSB are a good candidate for applying in white shrimp cultivation to maintain water quality and to protect shrimp diseases for promoting shrimp growth with higher survival rate. (C) 2017 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.aquaculture.2017.02.033

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Saline soil is one major problem that causes low productivity on rice, while paddy fields are also one source of methane (CH4) emissions that can have a considerable impact on global warming. By using purple nonsulfur bacteria (PNSB) it is possible to overcome both these serious problems because PNSB produce 5-aminolevulinic acid (ALA), a compound that reduces salt stress for plants, and they are also good competitors for methanogens in the paddy fields. Therefore, the objective of this study was to select salt resistant PNSB with an ability to release ALA and reduce CH4 emissions. The PNSB isolates used were obtained from saline paddy fields in southern Thailand and the best were selected on the basis of their good growth under conditions of aerobic dark and anaerobic light while being salt tolerant, released ALA and reduced CH4 emissions under microaerobic light conditions. Among the 272 PNSB isolates, TN114 was the best ALA producer while PP803 was the best to reduce CH4 emissions. Both selected PNSB strains grew well in glutamate acetate (GA) broth containing NaCl up to 6.00% but 0.25% NaCl was their optimal concentration for growth. Under salt stress with 0.25% NaCl, the strain TN114 released 25.63 mu M ALA in GA broth. In scaled-up experiments, when it was mixed with native soil flora in rice straw broth the strain TN114 released 13.44 mu M ALA and the strain PP803 reduced CH4 emissions by 88.41%. These two strains were identified as Rhodopseudomonas palustris according to both traditional and 16 S rRNA identifications. Overall the results demonstrated that they had a good potential as plant growth stimulating bacteria under salt stress, due to the release of ALA and also reduce CH4 emissions. (C) 2014 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.apsoil.2014.10.005

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

Removal of Na+ by binding with exopolymeric substances (EPS) from Rhodopseudomonas palustris TN114 and PP803 was investigated. The moderate negative correlation pairs (r(p)) between remaining Alcian blue and amount of Na+ adsorbed on EPS from strains TN114 and PP803 were -0.652 and -0.609. Both strains showed positive relationships between the amounts of EPS produced and bacterial growth. EPS from strain PP803 had a higher efficiency in removing Na+ than the EPS from strain TN114 based on their EC50 values (1.79 and 1.49 mg/mL for TN114 and PP803, respectively). The principal component from EPS of strain PP803 which was responsible for salt removal was purified and it was identified as a polysaccharide kDa) mainly composed of galacturonic acid. Overall results suggested that EPS is a key factor that our strains used to bind Na* allowing their survival in high NaC1 concentrations. (C) 2014 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.carbpol.2014.08.099

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The microbial transformation of the major mangosteen pericarp xanthone, alpha-mangostin (1) by the endophytic fungi Colletotrichum sp. MT02 and Phomopsis euphorbiae K12 resulted in the production of the five metabolites 2-6. Biotransformation with Colletotrichum sp. MT02 converted 1 into 17,18-dihydroxymangostanin (2) and cyclomangostanin (3), while incubation with P. euphorbiae K12 gave 12,13,20-trihydroxymangostin (4), 12,13,19-trihydroxymangostin (5), and 20-hydroxymangostanin (6) as transformation products. The structures of these metabolites were elucidated via spectroscopic analyses, and for compound 3, the structure was confirmed by X-ray crystallographic analysis. All metabolites are new, and metabolite 3 possessed an unusual structure of bis-ring fused xanthene in nature. In addition, substrate and all products were evaluated for the antimycobacterial activity against Mycobacterium tuberculosis as well as the cytotoxicity against breast cancer (MCF-7) cell lines. (C) 2014 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.molcatb.2014.02.010

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：UNIV CATOLICA DE VALPARAISO  

Background: Rice is globally one of the most important food crops, and NaCl stress is a key factor reducing rice yield. Amelioration of NaCl stress was assessed by determining the growth of rice seedlings treated with culture supernatants containing 5-aminolevulinic acid (ALA) secreted by strains of Rhodopseudomonas palustris (TN114 and PP803) and compared to the effects of synthetic ALA (positive control) and no ALA content (negative control).
Results: The relative root growth of rice seedlings was determined under NaCl stress (50 mM NaCl), after 21 d of pretreatment. Pretreatments with 1 mu M commercial ALA and 10X diluted culture supernatant of strain TN114 (2.57 mu M ALA) gave significantly better growth than 10X diluted PP803 supernatant (2.11 mu M ALA). Rice growth measured by dry weight under NaCl stress ordered the pretreatments as: commercial ALA N TN114 N PP803 N negative control. NaCl stress strongly decreased total chlorophyll of the plants that correlated with non-photochemical quenching of fluorescence (NPQ). The salt stress also strongly increased hydrogen peroxide (H2O2) concentration in NaCl-stressed plants. The pretreatments were ordered by reduction in H2O2 content underNaCl stress as: commercial ALA N TN114 N PP803 N negative control. The ALA pretreatments incurred remarkable increases of total chlorophyll and antioxidative activities of catalase (CAT), ascorbate peroxide (APx), glutathione reductase (GR) and superoxide dismutase (SOD); under NaCl stress commercial ALA and TN114 had generally stronger effects than PP803.
Conclusions: The strain TN114 has potential as a plant growth stimulating bacterium that might enhance rice growth in saline paddy fields at a lower cost than commercial ALA. (C) 2014 Pontificia Universidad Catolica de Valparaiso. Production and hosting by Elsevier B.V. All rights reserved.

DOI： 10.1016/j.ejbt.2013.12.004

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier Ltd  

Pochonicine is a polyhydroxylated pyrrolizidine alkaloid with a powerful inhibitory activity against β-Nacetylglucosaminidases. The proposed structure for pochonicine and the three diastereomers concerning its C-1 and/or C-3 positions were synthesized from N-acetyl-D-glucosamine through construction of the pyrrolizidine skeleton by two intramolecular amino cyclizations as key steps. This synthetic study not only revised the structure of the natural product to the corresponding 1,3-di-epi-form but also determined the absolute configuration as 1R, 3S, 5R, 6R, 7S, 7aR. Copyright © 2012 Published by Elsevier Ltd.

DOI： 10.1016/j.tetlet.2013.01.015

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TMG-chitotriomycin (1) produced by the actinomycete Streptomyces annulatus NBRC13369 was examined as a probe for the prediction of substrate specificity of β-N-acetylhexosaminidases (HexNAcases). According to the results of inhibition assays, 14 GH20 HexNAcases from various organisms were divided into 1-sensitive and 1-insensitive enzymes. Three representatives of each group were investigated for their substrate specificity. The 1-sensitive HexNAcases hydrolyzed N-acetylchitooligosaccharides but not N-glycan-type oligosaccharides, whereas the 1-insensitive enzymes hydrolyzed N-glycan-type oligosaccharides but not N-acetylchitooligosaccharides, indicating that TMG-chitotriomycin can be used as a molecular probe to distinguish between chitin-degrading HexNAcases and glycoconjugate-processing HexNAcases. © 2013 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.carres.2013.04.024

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：UNIV CATOLICA DE VALPARAISO  

The aims were to explore an appropriate isolating medium for obtaining purple nonsulfur bacteria (PNSB) for use as biofertilizers in saline paddy fields and to obtain pure cultures. We therefore chose a defined isolating medium containing 0.25% NaCl, (Glutamate-Acetate broth, GA) and a rice straw broth to compare them for numbers of PNSB obtained, time to obtain pure cultures, diversity and costs. A total of 30 water and 30 sediment samples were collected from saline paddy fields in southern Thailand and used to isolate PNSB in both the isolating media. Based on 60 samples and a period of 13 days incubation under anaerobic light conditions, a greater number of samples produced PNSB growth in GA broth after only day 3; however, after that the rice straw broth provided about a 2 fold increase in the number of samples that produced PNSB growth. Colonies isolated from GA broth required a significantly higher number of repeated streaking to obtain a pure culture (average 3.5) than those from rice straw broth (average 2.7) and the latter medium also produced significantly (P < 0.05) more isolates per sample. Sixty samples of water and sediment, from rice paddies with salinity (average, 3.43 +/- 0.67 mS/cm) and slight acidity (average, pH 5.84 +/- 0.42) provided 62 PNSB isolates by GA broth and 210 isolates by rice straw broth, and rice straw broth also produced a greater prevalence of PNSB. Estimates of the costs based on current prices of media, Gas Pak and electricity to obtain PNSB with the use of GA broth was roughly 6 times higher than for the rice straw broth.

DOI： 10.2225/vol15-issue6-fulltext-8

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Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

alpha-Mangostin (1), a prenylated xanthone isolated from the fruit hull of Garcinia mangostana L., was individually metabolized by two fungi, Colletotrichum gloeosporioides (EYL131) and Neosartorya spathulata (EYR042), repectively. Incubation of 1 with C. gloeosporioides (EYL131) gave four metabolites which were identified as mangostin 3-sulfate (2), mangostanin 6-sulfate (3), 17,18-dihydroxymangostanin 6-sulfate (4)and isomangostanin 3-sulfate (5). Compound 2 was also formed by incubation with N. spathulata (EYR042). The structures of the isolated compounds were elucidated by spectroscopic data analysis. Of the isolated metabolites, 2 exhibited significant anti-mycobacterial activity against Mycobacterium tuberculosis. (C) 2011 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.phytochem.2011.02.007

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

In order to explore compounds naturallly inhibitory to shrimp pathogenic vibrios, a culture filtrate of Pseudomonas sp. W3 at a pH of 2 was extracted with ethyl acetate (EtOAc) to produce 82.15 mg/l of a yellow-brown extract (EtOAc-W3) that had MIC values of 225-450 mu g/ml against the growth of 18 shrimp pathogenic Vibrio harveyi strains. The MIC of EtOAc-W3 against the most pathogenic strain PSU 2015 was 450 mu g/ml and this strain had the lowest LD(50) (50% lethal dose) to pacific white shrimp (Litopenaeus vannamei, PL 21). At this MIC value, EtOAc-W3 in artificial sea water (ASW) killed strain PSU 2015; however in natural sea water, only a partial growth inhibition was observed. The toxicity to pacific white shrimp and antivibrio activity of the EtOAc-W3 were investigated by conducting an experiment with 4 sets; native control (commercial ASW), EtOAc-W3 control (MIC/10, 45 mu g/ml), challenge (inoculation 6.0 x 10(6) c.f.u./ml PSU 2015) and treatment (6.0 x 10(6) c.f.u./ml PSU 2015 + 45 mu g/ml EtOAc-W3). The same experiment was repeated by increasing the dose of EtOAc-W3 to 90 mu g/ml (MIC/5). Both concentrations of EtOAc-W3 tested had no toxicity to postlarval shrimps. A significant decrease in shrimp mortality was observed over a 72 h period as approximately 80% of the shrimps died in each challenge set but only 63 and 23% died in the presence of 45 and 90 mu g/ml EtOAc-W3. The major component of EtOAc-W3 was supposed to be 2-heptyl-4-quinolone (HHQ) by FAB-MS and (1)H-NMR analyses of the purified fraction.

DOI： 10.1007/s11274-010-0529-x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

The reducing tetrasaccharide TMG-chitotriomycin (1) is an inhibitor of beta-N-acetylglucosaminidase (GlcNAcase), produced by the actinomycete Streptomyces anulatus NBRC13369. The inhibitor shows a unique inhibitory spectrum, that is, selectivity toward enzymes from chitin-containing organisms such as insects and fungi. Nevertheless, its structure-selectivity relationship remains to be clarified. In this study, we conducted a structure-guided search of analogues of 1 in order to obtain diverse N,N,N-trimethylglucosaminium (TMG)-containing chitooligosaccharides. In this approach, the specific fragmentation profile of 1 on ESI-MS/MS analysis was used for the selective detection of desired compounds. As a result, two new analogues, named TMG-chitomonomycin (3) and TMG-chitobiomycin (2), were obtained from a culture filtrate of 1-producing Streptomyces. Their enzyme-inhibiting activity revealed that the potency and selectivity depended on the degree of polymerization of the reducing end GlcNAc units. Furthermore, a computational modeling study inspired the inhibitory mechanism of TMG-related compounds as a mimic of the substrate in the Michaelis complex of the GH20 enzyme. This study is an example of the successful application of a MS/MS experiment for structure-guided isolation of natural products.

DOI： 10.1039/c0ob01090a

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：UNIV CATOLICA DE VALPARAISO  

Lactobacillus plantarum DW3 produced antifungal compounds that inhibited the growth of Rhodotorula mucilaginosa DKA, contaminating yeast in fermented plant beverages (FPBs) and various potential human pathogens. Phenyllactic acid (PLA) identified by gas chromatography- mass spectrometry (GC-MS) was produced at 31 mg/L PLA in MRS medium and 5 mg/ml inhibited growth of the target yeast in vitro by 90%. Other inhibitors were also present but not specifically identified. Results of in vitro tests showed that DW3 also had probiotic properties as it survived various human biological barriers resistance to pH 3, bile salts, growth without vitamin B(12) and the presence and absence of oxygen. Its inhibitory effect against foodborne pathogenic bacteria and spoilage organisms was higher than that found for a commercial strain Lactobacillus casei R. An acute oral toxicity test on ICR mice at a high single dose of either 10(9) and 10(12) cells per mouse for 14 days showed that DW3 had no adverse effect on the general health status and there was no evidence of bacteremia. Mice fed DW3 had a reduced weight gain compared to the control. No significant difference (p > 0.05) was found for the spleen weight index (SWI) among the treatment and control groups whereas there was a significant difference (p < 0.05) for the liver weight ratio (LWR) in a group fed with 10(12) cells per mouse when compared with the control group.

DOI： 10.2225/vol13-issue5-fulltext-1

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Pseudomonas sp. W3, a bacterium known to produce an extracellular alkaline protease, secreted secondary metabolites that inhibited pathogenic bacteria responsible for shrimp luminous vibriosis disease. Antivibrio compounds in the culture supernatant or culture filtrates (0.45 mu m and 0.22 mu m) of the isolate W3 were tested using an agar well diffusion method on a number of pathogenic vibrios. Vibrio harveyi PSU 2015 a pathogenic isolate was the most sensitive strain. The effectiveness of preparations from the isolate W3 against V. harveyi PSU 2015, and V. cholerae PSSCMI 0062 was in the order of culture supernatant > 0.45 mu m culture filtrate > 0.22 mu m culture filtrate. These extracellular antivibrio compounds also lysed both dead and living cells of V. harveyi PSU 2015. Results of the partial characterization tests indicated that there was some particulate antivibrio compound that was destroyed by treatment with enzymes particularly achymotrypsin, autoclaving at 121 degrees C for 15 min and was mostly removed by filtration through a 0.22 mu m filter. Most of the inhibitory compounds were of small molecular weight able to pass through a 0.22 mu m filter and were resistant to treatment with various enzymes, pH values between 4-8 and temperatures up to 121 degrees C for 30 min. The optimum pH for the antivibrio activity in the 0.45 mu m culture filtrate was between pH 6-7.

DOI： 10.2225/vol13-issue1-fulltext-2

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

A new polyhydroxylated pyrrolizidine alkaloid designated as pochonicine (1) was isolated from a solid fermentation culture of the fungal strain Pochonia suchlasporia var. suchlasporia TAMA 87. The structure of 1 was determined using NMR and MS techniques as (1R*, 3S*, 5S*, 6S*, 7R*, 7a S*)-5-acetamidomethyl-3-hydroxymethyl-1,6,7-trihydroxypyrrolizidine. Pochonicine (1) showed potent inhibition against beta-N-acetylglucosaminidases (GlcNAcases) of various organisms including insects, fungi, mammals, and a plant but no inhibition against beta-glucosidase of almond, alpha-glucosidase of yeast, or chitinase of Bacillus sp. The GlcNAcase inhibitory activity of pochonicine (1) was comparable to nagstatin, a potent GlcNAcase inhibitor of natural origin. (C) 2009 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.bmc.2009.08.052

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A novel beta-N-acetylglucosaminidase (GIcNAcase) inhibitor named TMG-chitotriomycin (1) was isolated from the culture filtrate of Streptomyces anulatus NBRC13369. The strain produced 1 only when colloidal chitin was used as the sole carbon source in the production medium. The structure of 1 was determined by spectral and constitutive sugar analyses of the corresponding alditol derivatives to be an equilibrated mixture of alpha-D-N,N,N-triMeGIcNH(2)-(1,4)-beta-D-GIcNAc-(1,4)-beta-D-GIcNAc-(1,4)-D-GlcNAc and its C-2 epimer of the reducing end residue. TMG-chitotriomycin (1) showed potent and selective inhibition of insect and fungal GIcNAcases with no inhibition of mammalian and plant GIcNAcases. In contrast, the known GIcNAcase inhibitor nagstatin potently inhibited all GIcNAcases. It should be emphasized that synthesized D-N,N,N-triMeGIcNH(2), which is the component sugar of 1, showed no inhibition of the insect Spodoptera litura GIcNAcase. These results suggest that the (GIcNAc)(3) unit positioned at the reducing end of 1 is essential for its enzyme inhibitory activity. The unique inhibitory spectrum of 1 will be useful to study chitinolytic systems and to develop selective fungicides or pesticides.

DOI： 10.1021/ja077641f

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MICROBIOL RES FOUNDATION  

DOI： 10.2323/jgam.54.79

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：VERLAG Z NATURFORSCH  

Under the bioassay-guided method, two diterpenes, 3-O-(2",3"-dimethylbutanoyl)-13-O-dodecanoylingenol (1) and 3-O-(2",3"-dimethylbutanoyl)-13-O-decanoylingenol (2) isolated from Euphorbia kansui, showed a pronounced antinematodal activity against the nematode Bursaphelenchus xylophilus at the same minimum effective dose (MED) of 5 mu g per cotton ball and still displayed antinematodal activity at a dose of 2.5 mu g per cotton ball. Compounds 3-6 were obtained, and the structure of the new compound 6 was elucidated based on 1D- and 2D-NMR analyses and physicochemical data. Preliminary structure-biological activity relationships of ingenane-type compounds were deduced.

DOI： 10.1515/znc-2008-1-211

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

Three compounds, 20-O-acetyl-[3-O-(2'E,4'Z)-deca-dienoyl]-ingenol (1), 20-O-acetyl-[5-O-(2'E,4'Z)-decadienoyl]-ingenol (2) and 3-O-(2'E,4'Z)-decadienoylingenol (3), were isolated from Euphorbia kansui under the bioassay-guided method. Each compound showed the same antinematodal activity against the nematode, Bursaphelenchus xylophilus, at a minimum effective dose (MED) of 5 mu g/cotton ball.

DOI： 10.1271/bbb.60677

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

The aim of this work was to study chemical structures and biological activities of rhamnolipids produced by Pseudomonas aeruginosa B189 isolated from milk factory waste. The culture produced two biosurfactants, a and b, which showed strong activity and were identified as L-rhamnopyranosyl-(L)-rhamnopyranosyl-beta-hydroxydecanoyl-beta-hydroxydecanoate or Rha-Rha-C-10-C-10 and (L)-rhamnopyranosyl-(L)-rhamnopyranosyl-beta-hydroxydecanoyl-beta-hydroxydodecanoate or Rha-Rha-C-10-C-12, respectively. Both compounds exhibited higher surfactant activities tested by the drop collapse test than several artificial surfactants such as SDS and Tween 80. Rhamnolipid a showed significant antiproliferative activity against human breast cancer cell line (MCF-7) at minimum inhibitory concentration (MIC) at 6.25 mu g/mL while rhamnolipid b showed MIC against insect cell line C6/36 at 50 mu g/mL. (c) 2006 Published by Elsevier Ltd.

DOI： 10.1016/j.biortech.2005.10.045

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

We have previously isolated cyclo(L-PrO-L-Tyr) and cyclo(L-Phe-L-Pro) from an actinomycete by a novel enzymatic conversion-guided method. Their tetradehydro derivatives, cyclo(Delta Pro-Delta Tyr) and cyclo(Delta Phe-Delta Pro), were enzymatically prepared. Neither of them inhibited cell division, in contrast to other tetradehydro cyclic dipeptides prepared previously. This result suggests that an NH proton in a diketopiperazine ring and/or conformation of the compound are important for the activity.

DOI： 10.1271/bbb.60651

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

The aim of this work was to study chemical structures and biological activities of rhamnolipids produced by Pseudomonas aeruginosa B189 isolated from milk factory waste. The culture produced two biosurfactants, a and b, which showed strong activity and were identified as L-rhamnopyranosyl-L-rhamnopyranosyl-beta-hydroxydecanoyl-beta-hydroxydecanoate or Rha-Rha C-10-C-10 and L-rhamnopyranosyl-L-rhamnopyranosyl-beta-hydroxydecanoyl-beta-hydroxydodecanoate or Rha-Rha C-10-C-12, respectively. Both compounds exhibited higher surfactant activities tested by the drop collapse test than several artificial surfactants such as SDS and Tween 80. Rhamnolipid a showed significant antiproliferative activity against human breast cancer cell line (MCF-7) at minimum inhibitory concentration (MIC) at 6.25 mu g/mL while rhamnolipid b showed MIC against insect cell line C6/36 at 50 mu g/mL. (c) 2005 Published by Elsevier Ltd.

DOI： 10.1016/j.biortech.2005.10.029

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Language：English   Publisher：Symposium on the chemistry of natural products  

DOI： 10.24496/intnaturalprod.2006.0__P-373_

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Language：English   Publisher：Symposium on the chemistry of natural products  

DOI： 10.24496/intnaturalprod.2006.0__P-374_

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Language：English   Publisher：Symposium on the chemistry of natural products  

DOI： 10.24496/intnaturalprod.2006.0__P-398_

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE INC  

We developed a method for screening cyclic dipeptide-producing microbes by enzymatic conversion. In this method, cyclic dipeptides are detected by the combination of: (i) conversion of cyclic dipeptides to dehydro cyclic dipeptides by cyclo(Leu-Phe) oxidase and (ii) detection of the dehydro derivative by UV spectrophotometry using TLC or HPLC analysis based on the absorbance change caused by the conversion. Using this method, the actinomycete strain A8 was isolated as a cyclic dipeptide-producing strain. The cyclic dipeptides were purified from the microbial extract by enzymatic detection-guided fractionation, and their structures were determined to be CYCIO(L-Phe-L-Pro) and cycIO(L-Pro-L-Tyr) by spectroscopic methods. (c) 2005 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.peptides.2005.08.017

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

In our previous study, water-soluble extracts from Bursaphelenchus xylophilus (B. xylophilus), a pine wood nematode, were shown to enhance interleukin (IL)-4 plus lipopolysaccharide-induced polyclonal immunoglobulin (Ig) E production in vitro in mice and to increase serum levels of an antigen-nonspecific IgE in vivo. Here we examined whether the nematode extracts stimulate immunofunctions of murine peritoneal macrophages. In both resident and inflammatory macrophages, Fey receptor-mediated phagocytosis was markedly activated by B. xylophilus extracts, while non-specific phagocytosis was not. The enhancement of specific phagocytosis was accompanied by an increase in the formation of IgG-Fc gamma receptor rosettes. B. xylophilus extracts also stimulated IL-1 beta production in both types of macrophages, and enhanced NO production and mRNA expression of inflammatory cytokines in inflammatory macrophages. These results indicate that the extracts of B. xylophilus contain an activating substance(s) for immunofunctions in macrophages, besides an enhancing factor for polyclonal IgE production.

DOI： 10.1271/bbb.70.203

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PESTICIDE SCI SOC JAPAN  

Microbial culture broths were screened for novel beta-N-acetylglucosaminidase (GlcNAcase) inhibitors specific for the enzyme of insect origin. Four strains of actinomycetes, Streptomyces griseoloalbus JCM4480, S. clauifer JCM5059. S. anulatus NBRC13369 and S. griseus subsp. rhodochrous NBRC13849, produced unique compounds showing selective inhibition of the insect GlcNAcase. In contrast, 4 fungal strains, Paecilomyces sp. F13, F30, P. carneus F2281 and Verticillium sp. F40, were found to produce GlcNAcase inhibitors showing a broad spectrum of inhibitory activity against GlcNAcases from insects, mammals, plants and fungi. These results indicated obvious differences in GlcNAcases between insects and other organisms. This is the first report of enzyme inhibitors specific for the GlcNAcase of insect origin. (c) Pesticide Science Society of Japan.

DOI： 10.1584/jpestics.31.41

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

Strain SM1 was isolated as a biosurfactant-producing microorganism from seawater and presumptively identified as Myroides sp., based on morphology, biochemical characteristics and 16S rDNA sequence. The strain produced surface-active compounds in marine broth, which were purified, using emulsification activity for n-hexadecane as an indicator. The purified compounds were identified by thin-layer chromatography, H-1- and C-13-NMR spectra and fast atom bombardment mass spectrometry as cholic acid, deoxycholic acid and their glycine conjugates. Type strains of the genus Myroides, M. odoratus JCM7458 and M. odoramitimus JCM7460, also produced these compounds. Myroides sp. strain SM1 possessed a biosynthetic route to cholic acid from cholesterol. Thus, bile acids were found as new products of prokaryotic cells, genus Myroides.

DOI： 10.1007/s00253-004-1777-1

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

Cyclo(His-Phe) was effectively converted to its dehydro, derivatives by the enzyme of Streptomyces albulus KO-23, an albonoursin-producing actinomycete. Two types of dehydro derivatives were isolated from the reaction mixture and identified as cyclo(DeltaHis-DeltaPhe) and cyclo(His-DeltaPhe). This is the first report on cyclo(His-DeltaPhe) and the enzymatic preparation of both compounds. Cyclo(DeltaHis-DeltaPhe), a tetradehydro cyclic dipeptide, exhibited a minimum inhibitory concentration of 0.78 mumol/ml inhibitory activity toward the first cleavage of sea urchin embryos, in contrast to cyclo(His-APhe) that had no activity. The finding that the isoprenylated derivative of cyclo(DeltaHis-DeltaPhe), dehydrophyenylahistin, had 2,000 times higher activity than cyclo(DeltaHis-DeltaPhe) indicates that an isoprenyl group attached to an imidazole ring of the compound was essential for the inhibitory activity.

DOI： 10.1271/bbb.68.2341

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Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY  

Aims: To isolate and characterize biosurfactants produced by a thermotolerant yeast isolated in Thailand.
Materials and Results: Yeast strains isolated from plant material in Thailand were first screened for the ability to produce lipase and biosurfactant. A strain Y12, identified as Candida ishiwadae by physiological tests, survived at 45degreesC and produced relatively large amounts of biosurfactants. From the culture filtrate of this strain, two glycolipid biosurfactants, a and b, were purified by solvent fractionation, silica gel and ODS column chromatographies. Compounds a and b were determined to be monoacylglycerols; 1-linoleylglycerol and 1-oleylglycerol, respectively. Both compounds exhibited higher surfactant activities tested by the drop collapse test than several artificial surfactants such as sodium dodecyl sulphate.
Conclusions: Glycolipid biosurfactants produced by a thermotolerant yeast, C. ishiwadae were characterized to be monoacylglycerols which exhibited high surfactant activities.
Significance and Impact of the Study: A thermotolerant yeast strain, C. ishiwadae, could be a potential candidate for producing monoacylglycerols which are useful in industrial applications.

DOI： 10.1111/j.1365-2672.2004.02202.x

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Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：VERLAG Z NATURFORSCH  

A water-soluble polysaccharide was isolated from the culture filtrate of a fungal strain, Sphaeropsis sp. TNPT116-Cz, as a novel insect chitinase inhibitor. It was purified to chromatographic homogeneity by ethanol precipitation, anion-exchange and gel filtration chromatography. Its molecular weight was estimated to be 16 kDa by gel filtration HPLC. Monosaccharide analysis showed that it contained glucose, galactose, N-acetylglucosamine and a deoxysugar. This polysaccharide showed potent and specific inhibitory activity against Spodoptera litura chitinase with an IC50 value of 28 nm.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPANESE PHARMACOLOGICAL SOC  

Bursaphelenchus xylophilus (B. xylophilus) is a pine wood nematode that is known to cause pine wilt disease. We report here that B. xylophilus extracts augmented the polyclonal immunoglobulin E (IgE) production induced by lipopolysaccharide (LPS) plus interleukin-4 (IL-4) both in murine splenocytes and purified B cells as determined by ELISA and ELIspot assays, but they did not cause such a promotion in the absence of either LPS or IL-4. We also observed that the antigen-nonspecific IgE levels were increased in sera of mice treated with B. xylophilus extracts, which were comparable to those of Ascaris suum extracts. These findings suggest that administration of B. xylophilus extracts could suppress allergic diseases via a saturation of mast cell Fcepsilon receptors or/and an inhibition of antigen-specific IgE synthesis to the allergen by a polyclonal response.

DOI： 10.1254/jphs.91.158

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Authorship：Lead author,　Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：The Society for Actinomycetes Japan  

DOI： 10.3209/saj.17_1

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Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PESTICIDE SCI SOC JAPAN  

Culture broths of fungal strains were screened for novel insect chitinase inhibitors using the Spodoptera litura chitinase inhibitory assay. The culture filtrates of 5 strains showed potent and specific inhibitory activity against the insect chitinase. Partial characterization showed that the active compounds produced by these strains were water-soluble macromolecular compounds which had not been hitherto reported as chitinase inhibitors. These novel chitinase inhibitors are, therefore, expected to be potential agents for insect control.

DOI： 10.1584/jpestics.28.33

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN ANTIBIOT RES ASSN  

A novel dehydrogenated cyclic dipeptide named as dehydrophenylahistin (DeltaPLH) was effectively prepared from a fungal metabolite (-)-phenylahistin by the enzymatic conversion catalyzed by the cell-free extract of Streptomyces albulus KO-23, an albonoursin-producing actinomycete. DeltaPLH exhibited more than 1,000 times as high potent inhibitory activity toward the first cleavage of sea urchin embryos as (-)-phenylahisitn which has been reported to be a cell cycle inhibitor and more than 10,000 as high as albonoursin, indicating that DeltaPLH is a promising leading compound for anticancer drugs.

DOI： 10.7164/antibiotics.55.1042

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN ANTIBIOT RES ASSN  

The cell-free extract of an albonoursin-producing strain Streptomyces albulus KO-23 catalyzes the conversion of cyclo(L-Leu-L-Phe) (1) to albonoursin (2). At the early stage of this conversion, two compounds were newly formed prior to albonoursin synthesis in the reaction mixture. These compounds were isolated and identified as (Z)-3-benzylidene-6-isobutyl-2,5-piperazinedione (4) and (Z)-3-benzyl-6-isobutylidene-2,5-piperazinedione (3). The cell-free extract also catalyzed the conversion of compound 3 or 4 to albonoursin. From these results, albonoursin was found to be biosynthesized via these compounds from cyclo(L-Leu-L-Phe). These didehydro diketopiperazines exhibited no inhibitory activity toward the first cleavage of sea urchin embryo in contrast to the higher cytotoxicity for albonoursin, indicating that dehydrogenation at alpha,beta -positions of both amino acid residues in diketopiperazines is required for cytotoxicity.

DOI： 10.7164/antibiotics.53.1257

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC BIOSCIENCE BIOENGINEERING JAPAN  

A bacterium, strain NM 5-3, isolated from soil exhibited the highest cyclo(Gly-Leu) (CGL)-hydrolyzing activity and was identified as Agrobacterium radiobacter. The reaction products from CGL were dipeptides (Leu-Gly and Gly-Leu) and amino acids (Leu and Gly). Inhibitors for the dipeptidase of this strain did not inhibit the hydrolysis of CGL to dipeptides, indicating that two distinct enzymes, CGLase and a dipeptidase, were involved in its hydrolysis. The activities of these two enzymes were separated by anion-exchange column chromatography. The results indicated that strain NM5-3 hydrolyzed CGL via the dipeptides to the corresponding amino acids. The CGLase fraction was found to catalyze the hydrolysis of cyclo(Gly-D-Leu), cyclo(Gly-Gly), cyclo(L-Ala-Gly), and cyclo(D-Ala-Gly). On the other hand, the dipeptidase fraction exhibited L-specific substrate specificity.

DOI： 10.1016/S1389-1723(00)80064-X

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：VERLAG Z NATURFORSCH  

The activity-guided chromatographic purification of the methanol extract of Knema hookeriana, using pine wood nematodes Bursaphelenchus xylophilus has successfully led to the isolation and characterization of two phenolic antinematodal compounds with minimun effective dose (MED) of 4.5 and 20 mu g/cotton ball (mu g/ bl.) or 0.018 and 0.073 mu M/cotton ball (mu M/bl.), respectively. Based on their chemical and spectral properties, these compounds were determined to be 3-undecylphenol (1) and 3-(8Z-tridecenyl)-phenol (2). These compounds were isolated for the first time from this species, and 2 seems to be a novel compound.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：VERLAG Z NATURFORSCH  

Sixty five methanolic extracts of Sumatran rainforest plants representing 63 species of 21 families were assayed in vivo for antinematodal activity against Bursaphelenchus xylophilus using our cotton ball-fungal mat method. Extracts of 27 plants species from 14 families exhibited antinematodal activity, while 37 species were inactive. Among them, three extracts of Bischofia javanica, Knema hookeriana and Areca catechu exhibited very strong activity at minimum effective dose (MED) of 0.7 mg/cotton ball (mg/bl.). Eight extracts from Allamanda cathartica, Ervatamia corymbosa, Hoya diversifolia, Bischofia javanica, Derris malacensis, Melastoma melabathricum, Ophiorriza konsteleary and Brucea sumatrana also showed strong activity (MED, 5 mg/bl.).

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier Science Publishers B.V.  

The cell-free extract of an albonoursin-producing strain, Streptomyces albulus KO-23, was found to catalyze the conversion of several cyclic dipeptides having Phe and aliphatic side chain-containing amino acid residues to the corresponding dehydro derivatives. 3Z-Benzylidene-6S-methyl-2,5-piperazinedione, 3Z-benzylidene-2,5-piperazinedione, and 3Z, 6Z-dibenzylidene-2,5-piperazinedione were prepared by this conversion system. Among the dehydro cyclic dipeptides prepared, tetradehydro derivatives exhibited inhibitory activity toward the first cleavage of sea urchin embryo, while didehydro derivatives did not. We previously found that cyclo(Leu-Phe) and its didehydro derivatives did not show any inhibitory activity, in contrast to high activity in the case of albonoursin. Taken together, these findings indicate that dehydrogenation at the α, β-positions of both amino acid residues in this type of cyclic dipeptide is required for the inhibitory activity.

DOI： 10.1016/S1389-1723(00)80039-0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

In the course of our screening program for bioactive compounds, a novel lipopeptide, nostofungicidine (1), was isolated from the methanolic extract of a field-grown terrestrial blue-green alga, Nostoc commune. The structure of nostofungicidine was elucidated by chemical degradation and extensive NMR measurements including DQF-COSY, HOHAHA, HMBC, and ROESY techniques. Nostofungicidine contains a novel beta-amino acid 3-amino-6-hydroxy stearic acid (Ahs) in its structure. (C) 1998 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0040-4039(98)00573-5

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

Two novel oxazolomycin isomers, oxazolomycins B (2) and C (3), were isolated from the fermentation broth of an oxazolomycin-producing strain, Streptomyces albus JA3453. Both compounds are geometrical isomers of oxazolomycin (1), the configurations of their triene moieties being (4'E, 6'E, 8'E) (2) and (4'Z, 6'E, 8'E) (3) while that of oxazolomycin fl) is (4'Z, 6'Z, 8'E), Compounds 2 and 3 exhibited potent inhibitory activity against crown gall formation with the same MIC (0.8 mu g/disk) as oxazolomycin. Compounds 2 and 3 showed no antibacterial activity against Agrobacterium tumefaciens, in contrast to oxazolomycin which has specific anti-A. tumefaciens activity.

DOI： 10.1271/bbb.62.438

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

One novel coumarin from Angelica dahurica roots was elucidated to be 5,8-di(2,3-dihydroxy-3-methylbutoxy)-psoralen. It occurs together with six other known coumarins and ferulic acid. The antimicrobial activity of the coumarins and ferulic acid were compared. Copyright (C) 1997 Elsevier Science Ltd.

DOI： 10.1016/S0031-9422(96)00634-6

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Preliminary antibacterial assay data that the Tectona grandis callus extract showed more antibacterial activity against E. coli and B. subtilis than the leaf extract led the authors to isolate the following antibacterial compounds from the callus. A mixture (3) of 2α,3β-dihydroxy-olean-12-en-28-oic acid (3b) and 2α,3β-dihydroxy-urs-12-en-28-oic acid (3b) exhibited the most potent antibacterial activity against both bacteria. The other 3 compounds, in the decreasing order of the activity, were identified as 2α,3α-dihydroxy-urs-12-en-28-oic acid (2), betulinic acid (1), and 2α,3α 23-trihydroxy-urs-12-en-28-oic acid (4). The antibacterial compounds (2, 3a, 3b and 4) were not detected or occurring in small quantities in the intact tissue, while they were observed in the callus. Only the less active compound 1 was present more abundantly in intact tissues than the callus.

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Language：English   Publisher：Japan Society for Bioscience, Biotechnology, and Agrochemistry  

The generation and accumulation of both benzoic acid (BA) and its conjugates were induced in suspension cultured cells of Pinus thunbergii by administering either phenylacetic acid (PA), a toxic metabolite of Bacillus cereus (strain HY-3) accompanying the pine wood nematode, or a lyophilized culture supernatant of this bacterium. BA conjugates reached their maximal levels in quantity two days after the administration and then decreased gradually until the 14th day, while BA increased significantly throughout this period. This pattern is similar to that in 3-year-old pine trees treated with PA, suggesting that the pathological reaction of pine tissues to the PA toxin might be involved in the pathogenesis mechanism for the pine wilt disease.

DOI： 10.1271/bbb.60.1410

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Language：English   Publisher：Japan Society for Bioscience, Biotechnology, and Agrochemistry  

Phenylacetic acid (PA), a toxin produced by three strains of bacteria accompanying the pine wood nematode, Bursaphelenchus xylophilus, was found to be formed in a culture of the nematode. An animal nutrient, nutrient broth (NB) medium, was more suitable for PA production of the accompanying bacteria than a vegetable nutrient, potato sucrose malt extract (PSM) medium. It is presumed that dead nematodes in the PSM medium provided the bacteria with nutrient for PA production. In the culture of virulent isolate OKD-3, more PA was detected than in that of less-virulent isolate OKD-1. PA production of the accompanying bacteria can dominate the pathogenicity of the nematode.

DOI： 10.1271/bbb.60.1413

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：VERLAG Z NATURFORSCH  

Bioassay-guided fractionation of the methanolic extract of Tamarindus indica fruits led to the isolation of L-(-)-di-n-butyl malate which exhibited a pronounced cytotoxic activity against sea urchin embryo cells. In order to study structure-activity relationships, close-structure relatives of di-n-butyl malate were synthesized using D-(+)- and L-(-)-malic acid as starting materials, and their cytotoxic activities were examined for the sea urchin embryo assay. L-(-)-Di-n-pentyl malate was the most effective inhibitor to the development of the fertilized eggs. Significant inhibitory activity was not seen in the esters of D-(-)-isomer.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：VERLAG Z NATURFORSCH  

In order to investigate new metabolites which are only induced in a plant callus infected by a pathogenic fungus, dual cultures with combinations of 10 species of fungi and 6 plant cell lines from different species were established. Among the combinations tested, the methanolic extract of a dual culture consisting of a plant cell line, Phytolacca americana and a fungus, Botrytis fabae showed a marked antifungal activity to Cladosporium herbarum. The main active constituent of this extract was identified to be phytolaccoside B (Pls B) by the spectroscopic analyses.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：VERLAG Z NATURFORSCH  

Syringaldehyde readily reacted in the horse-radish peroxidase (HRPOD) system. The ethyl acetate extract of the reaction mixture showed a marked antimicrobial activity against bacteria and fungi. After repeated column chromatography three potential antimicrobial compounds were obtained from the extract. The structural elucidation of active compounds was achieved by a combination of spectroscopic techniques and chemical modification.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：VERLAG Z NATURFORSCH  

A novel antimitotic compound named Nostodione A (Nd A) was isolated from a terrestrial blue-green alga Nostoc commune. Nostodione A disturbed the mitotic spindle formation of sea-urchin eggs and gave small spindles with low birefringence density. Nostodione A, however, had no phytotoxicity on the germination of a dicotyledonous plant Medicago sativa. Based on the spectral analysis and chemical degradation, the structure of Nostodione A was elucidated.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

Peroxidase (POD) catalyzed the polymerization of naturally occurring phenolics to give a variety of bioactive products. The guaiacol readily reacted in the POD system and afforded potential anti-microbial compounds. Three active phenols, 1, 2, and 3, were isolated from the reaction mixture. Spectroscopic analyses elucidated that 1 and 2 were a dimer and a trimer respectively originating from guaiacol. Compound 3 was readily oxidized to 4 by exposure to air. The structure of 4 was determined by a combination of chemical modification and spectroscopic analyses, and 3 was elucidated to be the hydroxyquinone form of 4.

DOI： 10.1271/bbb.58.133

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：VERLAG Z NATURFORSCH  

Natural polysaccharides were examined for their activity as elicitors of phytoalexins and flavonoids in alfalfa cotyledons. Only two polysaccharides, laminaran and pectic acid, had elicitor activity. Laminaran, which was more active than pectic acid, was hydrolyzed by tunicase and the hydrolysate was subjected to charcoal and gel filtration columns. Introduction of the pyridylamino group into the elicitor-active oligosaccharides was attempted in order to facilitate isolation. The pyridylamino derivatives were found to exhibit higher activity than the original oligosaccharides. Their liquid chromatography mass spectrometry (LC-MS) analysis revealed that the elicitor-active principles form two ion clusters with the same molecular weights, m/z 1070 and 1232. Their high performance liquid chromatography (HPLC) analysis showed three main peaks. The individual peaks (LN-1, 2,3) were collected and subjected to the alfalfa cotyledon assay. LN-3 showed the highest activity (minimum effective concentration, 0.8 mug/ml).

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Language：English   Publisher：Japan Society for Bioscience, Biotechnology, and Agrochemistry  

Peroxidase (POD) plays an important role in the biosynthesis of disease-lignin, which protects plants from fungal invasion. A novel POD inhibitor, ST-1 (1), was isolated from a fungus, and its chemical structure was elucidated to be 1,3-dihydro-4,5,6-trihydroxy-1,3-dimethoxy-7-methylisobenzofuran by a combination of chemical modification and spectroscopic techniques. ST-1 effectively scavenged oxygen radicals and also suppressed the phytoalexin accumulation in kidney bean.

DOI： 10.1271/bbb.57.1034

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DOI： 10.1271/kagakutoseibutsu.47.158

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DOI： 10.1201/b10195-21

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Other Link： http://search.jamas.or.jp/link/ui/2008137568

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Language：Japanese   Publisher：Japan Society for Bioscience, Biotechnology, and Agrochemistry  

DOI： 10.1271/nogeikagaku1924.76.539

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Language：Japanese   Publisher：Symposium on the chemistry of natural products  

Cyclic dipeptides (CDPs, diketopiperazines) and their derivatives are widely distributed in nature as secondary metabolites. Although some of dehydro-CDPs are known as cell cycle inhibitors, their effective syntheses have not been reported. We found that Streptomyces albulus KO23, an albonoursin-producing actinomycete, had a biosynthetic pathway from cyclo (Leu-Phe) to albonoursin, cyclo (ΔLeu-ΔPhe) by the fed-batch culture and the resting-cell experiments. And this enzyme activity was found to be effectively extracted in the cell-free extract of this actinomycete. This is the first report for the dehydrogenation of amino acid residues at α,β-positions in CDPs. Furthermore, this enzyme system enables us to synthesize several didehydro- and tetradehydro-CDPs from the corresponding CDPs. Among dehydro-CDPs prepared, the tetradehydro-CDPs exhibited cytotoxicity, while the didehydro-CDPs had no activity, indicating that dehydrogenation at α,β-positions of both amino acid residues in CDPs is required for cytotoxicity. Based on the above results, we speculated that a tetradehydro-CDP prepared from a didehydro-CDP exhibiting cytotoxicity might be a potent cytotoxic compound. Dehydrophenylahistin synthesized by this enzyme system from (-)-phenylahistin, which was recently reported to be a new cell cycle inhibitor, exhibited 1000 times higher inhibitory activity toward the first cleavage of sea urchin embryo than (-)-phenylahistin, and thus, would be a promising lead compound for antitumor agents.

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iketopiperazines(DKPs)and their derivatives are widely distributed in nature as secondary metabolites.Although some dehydroDKPs are known as cell cycle inhibitors, their effective synthesis has not been reported. We found that the cell-free extract from an albonoursin-producing actinomycete, Streptomyces albulus KO23, catalyzed the conversion of cyclo(Leu-Phe)to albonoursin. This is the first report on the dehydrogenation of amino acid residues at the α, β-positions in DKPs. Furthermore, this enzyme system enabled us to synthesize several didehydro- and tetradehydro- DKPs from the corresponding DKPs. Among the dehydroDKPs prepared, dehydrophenylahistin from (-)-phenylahistin, which was recently reported to be a new cell cycle inhibitor, exhibited 1000 times higher inhibitory activity toward the first clevage of sea urchin embrvo than (-)-phenylahistin, and would thus be a promising lead compound for antitumor agents. Agrobacterium radiobacter NM 5-3 isolated from soil hydrolyzed CGL to from dipeptides(i.e., Leu-Gly and Gly-Leu)and amino acids(i.e., Leu and Gly). This CGL hydrolysis was catalyzed by two distinct enzymes, CGLase and dipeptidase, which were separated by anion-exchange column chromatography. The CGLase was found to catalyze the hydrolysis of CGDL, CGG, CAG, and CDAG. On the other hand, the dipeptidase exhibited L-specific substrate specificity.

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Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10513850

Language：English   Publisher：Japan Antibiotics Research Association  

Albornoursin production was greatly enhanced when cycle (r-Leu-L-Phe) (CFL), a tetrahydro derivative of albonoursin, was added to the 2-day culture of an albonoursin-producing actinomycete, Streptomyces albulus KO-23. The increase in albonoursin production paralleled the amount of CFL added. Furthermore, the resting cells of the strain catalyzed the bioconversion of CFL to albonoursin. The optimum pH and temperature for the conversion were found to be pH 10.0 and 50°C. The feeding experiments and the resting-cell reactions revealed that albonoursin is biosynthesized by dehydrogenation of CFL in the actinomycete. This is the first report for a dehydrogenation of amino acid residues at the α,β-positions in cyclic dipeptides.

DOI： 10.7164/antibiotics.53.58

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Language：English   Publisher：JOHN WILEY & SONS LTD  

A previously reported bioassay method for Spodoptera litura chitinase inhibitors has been improved by use of colloidal chitin powder with a uniform particle size. This improvement made the assay four times more sensitive. Detection of three active supernatants by screening of supernatants and cell extracts from 135 fermentation broths has proved the efficiency of this improved method. (C) 1999 Society of Chemical Industry.

DOI： 10.1002/(SICI)1096-9063(199905)55:5<563::AID-PS972>3.0.CO;2-#

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The cell-free extract of Streptomyces sp. KO-2388, an albonoursin-producing strain, was found to catalyze the conversion of cyclo(L-Phe-L-Leu) to albonoursin. The conversion activity was simply determined by measuring the increase in ultraviolet (UV) absorption of the reaction mixture at 317 nm, lambda(max) (epsilon 25,400) of albonoursin, where cyclo(L-Phe-L-Leu) had no absorption. The optimum pH and temperature of this bioconversion using the cell-free extract were determined to be pH 8.0-9.5 and 60 degrees C, respectively. Under the optimum conditions, 620 mg/l of albonoursin was obtained with a conversion ratio of 62% after 24 h incubation. (C) 1999 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S1381-1177(98)00079-4

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The newly established GUS expression bioassay on the callus extracts of 22 species of plants revealed that the methanol extract of Phytolacca americana callus had the most potent inhibitory activity against agrobacterial plant transformation. A triterpene glycoside phytolaccoside B was isolated from the extract as a genuine plant transformation inhibitor having neither antiagrobacterial nor phytotoxic activity. This compound is promising for use as a biochemical probe for studies on the plant transformation mechanism. © 1999, Taylor &amp
Francis Group, LLC. All rights reserved.

DOI： 10.1271/bbb.63.1657

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Language：English   Publisher：Japan Antibiotics Research Association  

Strain KO-23, an actinomycete producing albonoursin as well as streptopyrone, was identified as Streptomyces albulus by morphological and biochemical studies. Fermentation conditions for albonoursin, a dehydro cyclic dipeptide exhibiting a pronounced inhibitory activity toward pronuclear fusion of sea urchin eggs, were optimized. Under the optimum conditions, the actinomycete produced 16 mg/liter of albonoursin, 30 times higher than that in the original culture. The cells cultivated under these conditions highly express biosynthetic enzymes for albonoursin, and thus are available for biosynthetic studies of dehydro cyclic peptides.

DOI： 10.7164/antibiotics.52.1017

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Language：Japanese   Publisher：岡山大学  

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Other Link： http://ousar.lib.okayama-u.ac.jp/11052

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Two novel oxazolomycin isomers, oxazolomycins B (2) and C (3), were isolated from the fermentation broth of an oxazolomycin-producing strain, Streptomyces albus JA3453. Both compounds are geometrical isomers of oxazolomycin (1), the configurations of their triene moieties being (4′E, 6′E, 8′E) (2) and (4′Z, 6′E, 8′E) (3) while that of oxazolomycin (1) is (4′Z, 6′Z, 8′E). Compounds 2 and 3 exhibited potent inhibitory activity against crown gall formation with the same MIC (0.8 μg/disk) as oxazolomycin. Compounds 2 and 3 showed no antibacterial activity against Agrobacterium tumefaciens, in contrast to oxazolomycin which has specific anti-A. tumefaciens activity. © 1998, Taylor &amp
Francis Group, LLC. All rights reserved.

DOI： 10.1271/bbb.62.438

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A convenient and quantitative bioassay method for evaluating the efficiency of plant transformation by Agrobacterium tumefaciens is important to search plant transformation inhibitors, possible biochemical probes for study on its mechanism. Our previously reported method, in which the plant transformation had been detected by the expression of β-glucuronidase in transformed plants, was improved. The difference between the previous and the improved methods is the use of suspension-cultured cells of Ageratum conyzoides as the host plant instead of Nicotiana tabacum BY-2
this alteration of the host enabled us to measure the β-glucuronidase activity in plant cells not only fluorometrically but also colorimetrically. The enzyme activity expressed in the cells of A. conyzoides was nearly 100 times higher than that of N. tabacum BY-2, and was enough for detection by colorimetric measurement. The method, therefore, is useful for a convenient determination of inhibitory activity against plant transformation. © 1998, Taylor &amp
Francis Group, LLC. All rights reserved.

DOI： 10.1271/bbb.62.2328

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Language：English   Publisher：SOC FERMENTATION BIOENGINEERING, JAPAN  

Arthrobacter sp. 1-3-1 and a coryneform rod bacterium, strain T-1-3-Y, which assimilate cyclo(Gly-Gly) and cyclo(Gly-L-Tyr) at high rates, respectively, were isolated from sell. Both bacteria exhibit diketopiperazine-hydrolyzing activity intracellularly in contrast to the extracellular cyclo(Gly-Gly) hydrolase reported previously. Arthrobacter sp. 1-3-1 shows a much broader substrate specificity than strain T-1-3-Y, indicating the diversity of diketopiperazine hydrolysis in nature.

DOI： 10.1016/S0922-338X(97)80147-X

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Curromycins A and B, antibiotics specific to Agrobacterium tumefaciens, inhibited crown gall formation on potato tubers. Their esters showed potent inhibitory activity against crown gall formation without any antibacterial activity. The change in biological activity of curromycins by simple esterification was similar to our previous observation in oxazolomycin. Curromycin esters are possible chemical probes to study the mechanism for plant transformation. © 1996, Taylor &amp
Francis Group, LLC. All rights reserved.

DOI： 10.1271/bbb.60.1535

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Trehalase inhibitors are promising as a specific insect growth regulator. Microbial culture filtrates are a good source of bioactive compounds, but some of them retain a significant amount of glucose, a major component of the culture medium, which makes it difficult to detect trehalase inhibitors because of high blank values for the glucose determination. To find a variety of trehalase inhibitors in glucose-rich microbial culture filtrates, an effective method for removing glucose by enzymatic conversion prior to a routine trehalase-inhibitory assay was devised. Conversion with glucose oxidase and catalase could completely remove 10mg/ml of glucose, and a wide variety of microbial culture filtrates with high glucose content could then be subjected to the routine bioassay. This method can also be applied to screen inhibitors for other enzymes whose activity is assayed by the amount of glucose formed. © 1995 Taylor &amp
Francis Group LLC.

DOI： 10.1080/bbb.59.398

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A rapid and quantitative bioassay method for inhibitors of plant transformation by Agrobacterium tumefaciens with an intron-GUS binary vector was devised as an alternative method to the time-consuming potato tuber disk assay. Among several host plants tested, tobacco BY-2 suspension cells were the most preferable for this GUS expression assay. Furthermore, as the phytotoxicity of the test material, if any, is apparent from the growth inhibition of BY-2 suspension cells, this method can exclude phytotoxic com pounds.

DOI： 10.1271/bbb.58.531

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A rapid and quantitative bioassay method for inhibitors of plant transformation by Agrobacterium tumefaciens with an intron-GUS binary vector was devised as an alternative method to the time-consuming potato tuber disk assay. Among several host plants tested, tobacco BY-2 suspension cells were the most preferable for this GUS expression assay. Furthermore, as the phytotoxicity of the test material, if any, is apparent from the growth inhibition of BY-2 suspension cells, this method can exclude phytotoxic com pounds.

DOI： 10.1271/bbb.58.531

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Language：Japanese   Publisher：天然有機化合物討論会  

Plants induce varied resistance-response toward microbial challenge. In order to establish an infection, pathogenic fungi must break such defense barriers as lignin, phytoalexins, and hydrolytic enzymes. At the early stage of infection, POD (peroxidase) activity is enhanced dramatically. POD and lignin accumulates at the infected site and then protects from further fungal invasion. The suppression of lignin deposition at the site might be of advantage to susceptible pathogenic fungi. We, therefore, conducted a comprehensive screening to obtain POD inhibitors from fungal cultures and a potent radical scavenger named ST-1 was isolated from a fungus, and its chemical structure was elucidated to be 1,3-dihydro-4,5,6-trihydroxy-1,3-dimethoxy-7-methylisobenzofuran by a combination of chemical modification and spectroscopic techniques. ST-1 effectively scavenged oxygen radicals and also suppressed the phytoalexin accumulation in kidney bean. These results suggested that such a mechanism can be enumerated as one of significant defense systems intervening plants and microbes. On the other hand, the POD, activated upon pathogenic challenge, could convert common plant phenolics into bioactive compounds which interfered with pathogen and insect attacks. This idea prompted us to examine the possibility. Guaiacol and other phenols were chosen as model substrates for the enzyme reaction system, and several products with novel structures were confirmed to have unique biological activities. This paper deals with the chemical structures of a novel radical scavenger (ST-1) and the POD products with anti-microbial activities and phytotoxicities.

DOI： 10.24496/tennenyuki.35.0_361

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A potato tuber disk assay of culture broths which had been confirmed to show neither antibacterial nor phytotoxic activity resulted in the discovery of a novel type of crown gall formation inhibitors, julimycin B-II and julichrome Q1.3. These two bisanthraquinones, products of Streptomyces sp. TM-71, inhibited crown gall formation on potato tuber disks at a minimum inhibitory dose of 1.6μg/disk without affecting the growth of Agrobacterium tumefaciens or the germination of alfalfa seeds. © 1993, Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.

DOI： 10.1271/bbb.57.2104

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Oxazolomycin diacetate, dipropionate, monobutyrate and dibutyrate were derived from oxazolomycin, a product of Streptomyces sp. KBFP-2025. These esters were potent inhibitors of crown gall formation on potato tuber disks upon infection with Agrobacterium tumefaciens. They showed neither antibacterial nor phytotoxic activity, whereas oxazolomycin showed both antibacterial and phytotoxic activities. Further, they had no inhibitory activity against A. tumefaciens on the potato tuber disk. The inhibitory activity of these esters against crown gall formation seems to be due to specific inhibition of the transformation of plants with A. tumefaciens. © 1992, Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.

DOI： 10.1271/bbb.56.1382

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Language：Japanese   Publisher：The Japanese Society for Chemical Regulation of Plants  

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Microbial production of benzoylformic acid (BF), which can be used as a substrate of enzymatic synthesis of (R)-(—)-mandelic acid, was investigated. Among 145 strains of yeasts and actinomycetes, Saccharomycopsis lipolytica (IAM 4964) was the best producer of BF from DL-phenylglycine (DL-PG). Culture conditions for BF production by the organism were optimized. When 0.2 % fructose as a carbon source and 0.7% Bacto-tryptone as a nitrogen source were used in the presence of 4 % dl-PG, 14.5 mg/ml of BF was produced (about 37 % molar yield) in 4 days of cultivation. BF was synthesized from the L-form of PG, but not from the D-form. The BF was isolated from culture broth in a crystalline form and physicochemically identified. © 1990, Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.

DOI： 10.1271/bbb1961.54.2101

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The crystalline formate dehydrogenase from Candida methanolica, which showed the highest specific activity (7.52 U/mg) so far reported, was characterized in detail. The enzyme is a dimer composed of identifical subunits, each containing one SH group related to the catalytic activity. The molecular mass of the enzyme is about 82–86 kDa. The Km values were found to be 3.0 mM for formate and 0.11 mM for NAD+. Even if the enzyme was incubated at pH 6.5–9.5 or at 55°C, the activity remained at 100%. Hg2+, Ni2+, NaCN, NaN3 and p‐chloromercuribenzoate strongly inhibited the enzyme activity, while the enzyme showed relatively high resistance to various chelating agents. The amino acid composition and some other physicochemical properties of the enzyme were studied. Immunological studies revealed that formate dehydrogenases of methanol‐utilizing yeasts immunologically more or less resemble each other, but differ from those of methanol‐utilizing bacteria. Furthermore, yeast formate dehydrogenases can be immunologically classified into three types: (a) the Candida type, (b) the Torulopsis/Hansenula/Pichia type and (c) the formaldehyde‐resistant yeast type. For simple and large‐scale preparation of the enzyme for practical use, treatment of cells of C. methanolica with the commercial cationic detergent, ‘Benzalkonium’ cation, is useful: the total and specific activities of the enzyme are 1.17‐fold and 3.10‐fold higher than those of the crude cell‐free extract, respectively. Copyright © 1989, Wiley Blackwell. All rights reserved

DOI： 10.1111/j.1432-1033.1989.tb14835.x

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Cystathionine γ‐synthase type II, which catalyzes l‐cystathionine synthesis from O‐acetyl‐l‐homoserine and l‐cysteine was purified from Bacillus sphaericus (IFO 3536) in seven steps. The purified enzyme appeared to be homogeneous by the results of polyacrylamide electrophoresis and ampholyte electrofocusing. The enzyme is a typical pyridoxal‐P dependent enzyme, has a molecular mass of 165 kDa and consists of four subunits identical in molecular mass. The enzyme catalyzed the γ‐replacement reaction and the elimination reaction was hardly detected even when a large amount of enzyme was added. In the replacement reaction, O‐acetyl‐l‐homoserine and the following thiol compounds: L and d‐cysteine, L and d‐homocysteine, sodium sulfide, various alkyl and aryl mercaptans, acted as the most suitable substrate to produce l‐cystathionine and the corresponding S‐substituted l‐homocysteine derivatives. Copyright © 1987, Wiley Blackwell. All rights reserved

DOI： 10.1111/j.1432-1033.1987.tb10742.x

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Cystathionine γ‐synthase type II, which catalyzes l‐cystathionine synthesis from O‐acetyl‐l‐homoserine and l‐cysteine was purified from Bacillus sphaericus (IFO 3536) in seven steps. The purified enzyme appeared to be homogeneous by the results of polyacrylamide electrophoresis and ampholyte electrofocusing. The enzyme is a typical pyridoxal‐P dependent enzyme, has a molecular mass of 165 kDa and consists of four subunits identical in molecular mass. The enzyme catalyzed the γ‐replacement reaction and the elimination reaction was hardly detected even when a large amount of enzyme was added. In the replacement reaction, O‐acetyl‐l‐homoserine and the following thiol compounds: L and d‐cysteine, L and d‐homocysteine, sodium sulfide, various alkyl and aryl mercaptans, acted as the most suitable substrate to produce l‐cystathionine and the corresponding S‐substituted l‐homocysteine derivatives. Copyright © 1987, Wiley Blackwell. All rights reserved

DOI： 10.1111/j.1432-1033.1987.tb10742.x

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Language：English   Publisher：Springer-Verlag  

Utilizing the γ-replacement reaction of Streptomyces cystathionine γ-lyase (EC 4.4.1.1.), an efficient production method for l-cystathionine has been established. Under optimal conditions, 50 mM l-cystathionine was synthesized from 50 mM O-succinyl-l-homoserine and 50 mM l-cysteine, added in four stages to the reaction mixture, with a substrate conversion rate of 100%. This productivity (11 gl-1 of reaction mixture) is about 3.5 times higher than that with l-homoserine and l-cysteine as substrates. © 1986 Springer-Verlag.

DOI： 10.1007/BF00250516

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Applicant：ネリアス・ファーマシュティカルズ・インコーポレーテッド

Application no：特願2001-553764  Date applied：2000.9.29

Patent/Registration no：特許第4810043号  Date registered：2011.8.26 

J-GLOBAL

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