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Journal of General and Applied Microbiology

Toshihiro Kojo, Chihiro Kadooka, Marisa Komohara, Shiori Onitsuka, Miya Tanimura, Yukiko Muroi, Shugo Kurazono, Yohei Shiraishi, Ken Oda, Kazuhiro Iwashita, Masahira Onoue, Kayu Okutsu, Yumiko Yoshizaki, Kazunori Takamine, Taiki Futagami, Kazuki Mori, Hisanori Tamaki
Aspergillus luchuensis is a kuro (black) koji fungus that has been used as a starch degrader for the awamori- and shochu-making industries in Japan. In this study, we investigated the effect of ion beam irradiation on A. luchuensis RIB2601 and obtained a high starch-degrading mutant strain U1. Strain U1 showed reduced growth rate, whereas it showed higher α-amylase, glucoamylase, and α-glucosidase activities on a mycelial mass basis than the wild type (wt) strain both on agar plates and in rice koji. In addition, strain U1 showed higher N-acetylglucosamine content in the cell wall and higher sensitivity to calcofluor white, suggesting a deficiency in cell wall composition...
October 17, 2017: Journal of General and Applied Microbiology
Ikuko Nishimura, Yuh Shiwa, Atsushi Sato, Tetsuya Oguma, Hirofumi Yoshikawa, Yasuji Koyama
No abstract text is available yet for this article.
October 17, 2017: Journal of General and Applied Microbiology
Sousuke Imamura, Keiko Taki, Kan Tanaka
No abstract text is available yet for this article.
September 26, 2017: Journal of General and Applied Microbiology
Wasana Suyotha, Hidehisa Fujiki, Vipavee Cherdvorapong, Kazuyoshi Takagi, Shigekazu Yano, Mamoru Wakayama
Thermally stable α-1,3-glucanase HF65 was purified from culture filtrate of Streptomyces thermodiastaticus HF3-3. The molecular mass of this enzyme was estimated to be 65 kDa and 45.7 kDa by using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and size exclusion chromatography, respectively. The purified enzyme retained more than 50% of maximum activity even after incubation at 65°C more than 2 h. Moreover, α-1,3-glucanase HF65 was stable in the presence of chemicals like SDS, benzethonium chloride, and sodium fluoride at a concentration of 1%...
September 26, 2017: Journal of General and Applied Microbiology
Miki Tashiro, Akira Fujii, Shigeko Kawai-Noma, Kyoichi Saito, Daisuke Umeno
To achieve an efficient production of geraniol and its derivatives in Escherichia coli, we aimed to improve the activity of geraniol synthase (GES) through a single round of mutagenesis and screening for higher substrate consumption. We isolated GES variants that outperform their parent in geraniol production. The analysis of GES variants indicated that the expression level of GES was the bottleneck for geraniol synthesis. Over-expression of the mutant GESM53 with a 5'-untranslated sequence designed for high translational efficiency, along with the additional expression of mevalonate pathway enzymes, isopentenyl pyrophosphate isomerase, and geranyl pyrophosphate synthase, yielded 300 mg/L/12 h geraniol and its derivatives (>1000 mg/L/42 h in total) in a shaking flask...
September 26, 2017: Journal of General and Applied Microbiology
Meiru Si, Yanyan Feng, Keqi Chen, Yiwen Kang, Can Chen, Yao Wang, Xihui Shen
Methionine sulphoxide reductases (Msr) are able to reduce methionine sulfoxide to methionine and protect bacteria against reactive oxygen species (ROS). Many organisms express both methionine sulphoxide reductase A (MsrA), specific for methionine-S-sulfoxide and methionine sulphoxide reductase B (MsrB), active against methionine-R-sulfoxide. Corynebacterium glutamicum expresses MsrA, the function of which has been well defined; however, the function of MsrB has not been studied. Whether MsrB and MsrA play an equally important role in the antioxidant process is also poorly understood...
September 12, 2017: Journal of General and Applied Microbiology
Takeshi Sato, Kazuhito Inoue, Hidehiro Sakurai, Kenji V P Nagashima
The efficiency of hydrogen gas production by nitrogenase in bacteria has been improved by the inhibition of antagonistic activity by the uptake hydrogenase. In this study, a mutant lacking the gene coding for the uptake hydrogenase was generated from the photosynthetic beta-proteobacterium Rubrivivax gelatinosus IL144 to explore new ways of hydrogen gas production driven by light energy. The mutant cells produced 25-30% higher amounts of molecular hydrogen than the wild-type cells under nitrogen-deficient conditions under light...
September 12, 2017: Journal of General and Applied Microbiology
Akira Ishihama
The model organism, Escherichia coli, contains a total of more than 4,500 genes, but the total number of RNA polymerase (RNAP) core enzyme or the transcriptase is only about 2,000 molecules per genome. The regulatory targets of RNAP are, however, modulated by changing its promoter selectivity through two-steps of protein-protein interplay with 7 species of the sigma factor in the first step, and then 300 species of the transcription factor (TF) in the second step. Scientists working in the field of prokaryotic transcription in Japan have made considerable contributions to the elucidation of genetic frameworks and regulatory modes of the genome transcription in E...
September 12, 2017: Journal of General and Applied Microbiology
Guadalupe Jiménez-Galisteo, Ester Fusté, Elisa Muñoz, Teresa Vinuesa, Tom G Villa, Roland Benz, Angel Domínguez, Miguel Viñas
Gordonia jacobaea is a bacterium belonging to the mycolata group characterized by its ability to produce carotenoids. Mycolic acids in the cell wall contribute to reducing the permeability of their envelopes requiring the presence of channel-forming proteins to allow the exchange of hydrophilic molecules with the surrounding medium. Identification and purification of the channel-forming proteins was accomplished by SDS-PAGE, Mass spectrometry and Mass peptide fingerprinting and the channel-forming activity was studied by reconstitution in lipid bilayers...
August 23, 2017: Journal of General and Applied Microbiology
Yang-Dao Wei, Ya Li, Chun Deng, Shi-Hua Wu, Cui-Ji Huang, Yi Yi
A gene (gkdA) (741 bp) encoding a putative protein of 247 amino acids was cloned from the Bacillus licheniformis SR01. The protein was expressed in Escherichia coli BL21 with a molecular mass estimated by SDS-PAGE of approximately 28.03 kDa and showed a calculating isoelectric point (pI) of 6.42. Structure analysis and function identification showed that the enzyme was a multifunctional glycosidase. Its specific activity was 0.013 U/μg. The recombinant glycosidase showed a maximum activity at 50°C and pH 7...
August 23, 2017: Journal of General and Applied Microbiology
Ratchanu Meidong, Sompong Doolgindachbaporn, Winai Jamjan, Kenji Sakai, Yukihiro Tashiro, Yuki Okugawa, Saowanit Tongpim
The use of probiotic bacteria to control bacterial infection in farmed fish is of clear practical interest. The aims of this study were to isolate and select a probiotic Bacillus sp. and to evaluate the effects of its supplementation on the growth and disease resistance of hybrid catfish. Bacillus siamensis strain B44v, selectively isolated from Thai pickled vegetables (Phak-dong), displayed a high potential as a probiotic in catfish culture. This bacterium produced a bacteriocin-like substance and exhibited a broad-spectrum antibacterial activity inhibiting both Gram-positive and Gram-negative bacteria, especially the fish pathogens Aeromonas hydrophila and Streptococcus agalactiae...
July 27, 2017: Journal of General and Applied Microbiology
Arup Jyoti Das, Tatsuro Miyaji, Sankar Chandra Deka
Two types of starter cakes, viz. amou and perok-kushi, used in the production of rice beer in Assam, India, by the Bodo and Deori communities, respectively, were used for the isolation of amylolytic fungi. Based on the sequencing of their internal transcribed spacer (ITS) regions the fungi were identified as Amylomyces rouxii and Rhizopus oryzae, and given the strain names TU460 and TU465, respectively. Both the strains showed the ability to degrade and saccharify starch. The glucoamylase activity was considerably high in A...
July 27, 2017: Journal of General and Applied Microbiology
Yuu Utashima, Satoshi Yamashita, Toshi-Hide Arima, Kazuo Masaki
No abstract text is available yet for this article.
July 27, 2017: Journal of General and Applied Microbiology
M Suganthi, P Senthilkumar, S Arvinth, K N Chandrashekara
The tea mosquito bug (TMB), Helopeltis spp. (Hemiptera: Miridae) is an insidious pest that poses a significant economical threat to tea plantations. Pseudomonas cultures are being used extensively for pest management which, however, resulting in a low mortality rate of insects and which has prompted us to search for a new microbial metabolite for TMB control. A chitinase purified from P. fluorescens and partially characterized by our group showed insecticidal activity against TMB. The mode of action behind chitinase toxicity is the enzymatic hydrolysis of chitin, which is a common constituent of the insect exoskeleton and gut lining of the peritrophic membrane...
July 6, 2017: Journal of General and Applied Microbiology
Eriko Itoh, Ryosuke Shigemoto, Ken-Ichi Oinuma, Motoyuki Shimizu, Shunsuke Masuo, Naoki Takaya
Late-stage cultures of filamentous fungi under nutrient starvation produce valuable secondary metabolites such as pharmaceuticals and pigments, as well as deleterious mycotoxins, all of which have remarkable structural diversity and wide-spectrum bioactivity. The fungal mechanisms regulating the synthesis of many of these compounds are not fully understood, but sirtuin A (SirA) is a key factor that initiates production of the secondary metabolites, sterigmatocystin and penicillin G, by Aspergillus nidulans...
July 1, 2017: Journal of General and Applied Microbiology
Akinori Kato, Shuhei Ueda, Taku Oshima, Yoichi Inukai, Toshihide Okajima, Masayuki Igarashi, Yoko Eguchi, Ryutaro Utsumi
The WalK/WalR two-component system is essential for cell wall metabolism and thus for cell growth in Bacillus subtilis. Waldiomycin was previously isolated as an antibiotic that targeted WalK, the cognate histidine kinase (HK) of the response regulator, WalR, in B. subtilis. To gain further insights into the action of waldiomycin on WalK and narrow down its site of action, mutations were introduced in the H-box region, a well-conserved motif of the bacterial HKs of WalK. The half-maximal inhibitory concentrations (IC50s) of waldiomycin against purified WalK protein with triple substitutions in the H-box region, R377M/R378M/S385A and R377M/R378M/R389M, were 26...
July 1, 2017: Journal of General and Applied Microbiology
Watsapon Wattanasuepsin, Bungonsiri Intra, Jirayut Euanorasetr, Yoshihiro Watanabe, Ratchanee Mingma, Wataru Fukasawa, Mihoko Mori, Atsuko Matsumoto, Kazuro Shiomi, Watanalai Panbangred
A new pyrrole compound, 1-methoxypyrrole-2-carboxamide, was obtained from a culture broth of Streptomyces griseocarneus SWW368, which was isolated from the rhizospheric soil under a Para rubber tree (Hevea brasiliensis). The chemical structure was elucidated by 1D NMR, 2D NMR, and MS, as a pyrrole ring with a N-methoxy group and a primary amide group. It exhibited antibacterial properties against Kocuria rhizophila, Staphylococcus aureus and Xanthomonas campestris pv. oryzae; however, cytotoxicity of the compound at 714 μM against several mammalian tumor cell lines, i...
May 15, 2017: Journal of General and Applied Microbiology
Marwa Jardak, Faten Abdelli, Rahma Laadhar, Raphael Lami, Didier Stien, Sami Aifa, Sami Mnif
The bacterial diversity associated with biofilm-forming ability was studied. Eighteen bacterial strains were isolated from a microbial film collected from the roof of an old house located in Sfax, Tunisia. The purity of these microorganisms was confirmed by microscopic observation after repeated streaking on a Tryptic Soy agar medium. Biofilm formation was estimated using preliminary tests including a motility test, microbial adhesion to solvents (MATS), and the Congo Red Agar method (CRA). Since these tests showed no significant result, microplate tests, such as crystal violet and resazurin assays, were used...
May 15, 2017: Journal of General and Applied Microbiology
Koki Nishino, Hiromi Nishida
No abstract text is available yet for this article.
May 15, 2017: Journal of General and Applied Microbiology
Junta Sugiyama, Tomohiko Kiyuna, Miyuki Nishijima, Kwang-Deuk An, Yuka Nagatsuka, Nozomi Tazato, Yutaka Handa, Junko Hata-Tomita, Yoshinori Sato, Rika Kigawa, Chie Sano
Microbial outbreaks and related biodeterioration problems have affected the 1300-year-old multicolor (polychrome) mural paintings of the special historic sites Takamatsuzuka Tumulus (TT) and Kitora Tumulus (KT). Those of TT are designated as a national treasure. The microbiomes of these tumuli, both located in Asuka village, Nara, Japan, are critically reviewed as the central subject of this report. Using culture-dependent methods (conventional isolation and cultivation), we conducted polyphasic studies of the these microbial communities and identified the major microbial colonizers (Fusarium spp...
May 12, 2017: Journal of General and Applied Microbiology
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