著者

Satoru Watanabe Shunsuke Saito Yasuhiro Suezaki Takeshi Seguchi Ryudo Ohbayashi

出版者

Applied Microbiology, Molecular and Cellular Biosciences Research Foundation

雑誌

The Journal of General and Applied Microbiology (ISSN:00221260)

巻号頁・発行日

pp.2019.11.005, (Released:2020-02-25)

参考文献数

18

被引用文献数

1

---

In bacterial DNA replication, the initiator protein DnaA binds to the multiple DnaA box sequences located at oriC to facilitate the unwinding of duplex DNA strands. The cyanobacterium Synechococcus elongatus PCC 7942, which contains multiple chromosomal copies per cell, has DnaA box (like sequences around the oriC region, which is located upstream of dnaN. We previously observed the binding of DnaA around the oriC region; however, the DNA-binding specificity of DnaA to DnaA box sequences has not been examined. Here, we analyzed the binding specificity of DnaA protein to the DnaA box in S. elongatus by using bio-layer interferometry (BLI), a method for monitoring intermolecular interactions. We observed that recombinant DnaA protein recognized specifically the DnaA box sequence TTTTCCACA in vitro. In addition, DNA binding activity was significantly increased by R328H mutation of DnaA. This is the first report to characterize DnaA binding to the DnaA box sequence in cyanobacteria.

著者

Kiran Gupta P. P. Baruah

出版者

Applied Microbiology, Molecular and Cellular Biosciences Research Foundation

雑誌

The Journal of General and Applied Microbiology (ISSN:00221260)

巻号頁・発行日

pp.2019.09.001, (Released:2020-01-24)

参考文献数

55

被引用文献数

1

---

Cyanobacteria are an important component in the rice field ecosystem and are a well known source of natural biofertilizer. Pesticidal application for the control of pests in rice field soil has led to several environmental problems, and poses a great threat to these beneficial microorganisms. Studies on the impact of pesticides on the diazotrophic growth and survivability of these microorganisms have recently gained much attention. The present paper describes the effects of an iterated use of the insecticide deltamethrin (2.8% EC) on the growth and nitrogen fixation capacity of the filamentous cyanobacterium Calothrix sp. (strain GUEco 1002). This organism has shown a varying degree of sensitivity to the insecticide. For evaluating the deltamethrin toxicity, the test organism was subjected to varying concentrations of deltamethrin i.e. 17.5 ppm, 35 ppm, 70 ppm and 140 ppm based upon LC50 for 20 days. The data obtained in the laboratory revealed that the treatment of the test organism with deltamethrin (17.5–140 ppm) negatively affected its growth, pigments, protein and nitrogen content in a time dose dependent manner. In contrast, carbohydrate content significantly increased with increasing concentrations of deltamethrin, this effect being more prominent at 140 ppm treatment (38%). At this high level (140 ppm), the test organism showed a significant decrease in dry weight biomass (46%), chlorophyll-a (72%), carotenoids (57%), phycocyanin (67%), protein (69%) and nitrogen content (61%) over the control. A little, but insignificant, stimulatory effect on nitrogen content was recorded at 17.5 ppm of the insecticide which however, was the opposite in the case of growth, pigments, carbohydrate and protein content.

著者

Ryoji Koike Yuichi Kato Shigeki Ehira

出版者

Applied Microbiology, Molecular and Cellular Biosciences Research Foundation

雑誌

The Journal of General and Applied Microbiology (ISSN:00221260)

巻号頁・発行日

pp.2019.10.002, (Released:2019-12-17)

参考文献数

26

被引用文献数

2

---

Cyanobacteria are a morphologically and physiologically diverse group of bacteria, which contains unicellular and multicellular filamentous strains. Some filamentous cyanobacteria, such as Anabaena sp. strain PCC 7120, form a differentiated cell called a heterocyst. The heterocyst is a specialized cell for nitrogen fixation and is differentiated from a vegetative cell in response to depletion of combined nitrogen in the medium. In Anabaena PCC 7120, it has been demonstrated that hetR, which encodes a transcriptional regulator, is necessary and sufficient for heterocyst differentiation. However, comprehensive genomic analysis of cyanobacteria has shown that hetR is present in non-heterocyst-forming cyanobacteria. Almost all filamentous cyanobacteria have hetR, but unicellular cyanobacteria do not. In this study, we conducted genetic and biochemical analyses of hetR (NIES39_C03480) of the non-heterocyst-forming cyanobacterium Arthrospira platensis NIES-39. HetR of A. platensis was able to complement the hetR mutation in Anabena PCC 7120 and recognized the same DNA sequence as Anabaena HetR. A search of the A. platensis genome revealed the HetR-recognition sequence within the promoter region of NIES39_O04230, which encodes a protein of unknown function. Expression from the NIES39_O04230 promoter could be suppressed by HetR in Anabaena PCC 7120. These data support the conclusion that NIES39_O04230 is regulated by HetR in A. platensis NIES-39.

著者

Hazuki Hasegawa Tatsuhiro Tsurumaki Ikki Kobayashi Sousuke Imamura Kan Tanaka

出版者

Applied Microbiology, Molecular and Cellular Biosciences Research Foundation

雑誌

The Journal of General and Applied Microbiology (ISSN:00221260)

巻号頁・発行日

pp.2019.05.002, (Released:2019-09-10)

参考文献数

34

被引用文献数

5

---

Proteins that bind to RNA polymerase (RNAP) sigma factors play important roles in various transcriptional regulations. In this study, we identified a candidate of the principal sigma factor interacting protein in cyanobacteria, named SinA, based on a previous comprehensive protein interaction study (Sato et al., 2007) and analyzed this in the cyanobacterium Synechococcus elongatus PCC 7942. SinA is highly conserved among cyanobacteria and a knock out mutant showed defective growth at a usually permissive high temperature (40°C). Because this observation suggested SinA involvement in heat-inducible transcriptional activation, we examined heat-inducible protein gene hspA expression after temperature upshifts. The second-step induction disappeared after 15 min in the sinA mutant. In vivo pull-down experiments demonstrated the interaction between SinA and the principal sigma factor RpoD1. This SinA-RpoD1 complex was associated with an RNAP core enzyme under growth temperatures, but was dissociated after a temperature upshift. Based on these results, we propose a function of SinA to facilitate the substitution of the principal sigma factor with alternative sigma factors under heat-stressed conditions.

著者

Yusuke Suzuki Atsushi Kouzuma Kazuya Watanabe

出版者

Applied Microbiology, Molecular and Cellular Biosciences Research Foundation

雑誌

The Journal of General and Applied Microbiology (ISSN:00221260)

巻号頁・発行日

pp.2019.04.007, (Released:2019-08-23)

参考文献数

26

被引用文献数

6

---

Here, we developed an all-in-one, broad host-range CRISPR/Cas9 vector system widely applicable to genome editing of proteobacteria. Plasmid pBBR1-Cas9 was constructed by cloning the cas9 gene from Streptococcus pyogenes into the broad host-range plasmid pBBR1MCS-2. We evaluated its applicability for frameshift mutagenesis of Shewanella oneidensis MR-1. Significant cell death was observed when MR-1 cells were transformed with a pBBR1-Cas9 derivative that expressed a single-guide RNA targeting the crp gene. However, cell death was partially prevented when a donor DNA fragment containing a modified crp sequence with a frameshift mutation was introduced using the same vector. All transformants (9 colonies) contained the expected frameshift mutation in their chromosomal crp genes. These results indicate that this vector system efficiently introduced CRISPR/Cas9-mediated double-strand DNA breaks and subsequent homology-directed repair. This work provides a simple and powerful genome-editing tool for proteobacteria that can harbor pBBR1-based plasmids.

著者

Yuu Utashima Satoshi Yamashita Toshi-Hide Arima Kazuo Masaki

出版者

Applied Microbiology, Molecular and Cellular Biosciences Research Foundation

雑誌

The Journal of General and Applied Microbiology (ISSN:00221260)

巻号頁・発行日

vol.63, no.4, pp.254-257, 2017 (Released:2017-09-05)

参考文献数

17

被引用文献数

4

著者

Saori Watahiki Nobutada Kimura Atsushi Yamazoe Takamasa Miura Yuji Sekiguchi Naohiro Noda Satoko Matsukura Daisuke Kasai Yoh Takahata Hideaki Nojiri Masao Fukuda

出版者

Applied Microbiology, Molecular and Cellular Biosciences Research Foundation

雑誌

The Journal of General and Applied Microbiology (ISSN:00221260)

巻号頁・発行日

pp.2018.10.003, (Released:2019-03-08)

参考文献数

36

被引用文献数

7

---

Bioremediation may affect the ecological system around bioremediation sites. However, little is known about how microbial community structures change over time after the initial injection of degraders. In this study, we have assessed the ecological impact of bioaugmentation using metagenomic and metatranscriptomic approaches to remove trichlorinated ethylene/cis-dichloroethylene (TCE/cDCE) by Rhodococcus jostii strain RHA1 as an aerobic chemical compound degrader. Metagenomic analysis showed that the number of organisms belonging to the genus Rhodococcus, including strain RHA1, increased from 0.1% to 76.6% of the total microbial community on day 0 at the injection site. Subsequently, the populations of strain RHA1 and other TCE/cDCE-degrading bacteria gradually decreased over time, whereas the populations of the anaerobic dechlorinators Geobacter and Dehalococcoides increased at later stages. Metatranscriptomic analysis revealed a high expression of aromatic compound-degrading genes (bphA1-A4) in strain RHA1 after RHA1 injection. From these results, we concluded that the key dechlorinators of TCE/cDCE were mainly aerobic bacteria, such as RHA1, until day 1, after which the key dechlorinators changed to anaerobic bacteria, such as Geobacter and Dehalococcocides, after day 6 at the injection well. Based on the α-diversity, the richness levels of the microbial community were increased after injection of strain RHA1, and the microbial community composition had not been restored to that of the original composition during the 19 days after treatment. These results provide insights into the assessment of the ecological impact and bioaugmentation process of RHA1 at bioremediation sites.

著者

Saori Watahiki Nobutada Kimura Atsushi Yamazoe Takamasa Miura Yuji Sekiguchi Naohiro Noda Satoko Matsukura Daisuke Kasai Yoh Takahata Hideaki Nojiri Masao Fukuda

出版者

Applied Microbiology, Molecular and Cellular Biosciences Research Foundation

雑誌

The Journal of General and Applied Microbiology (ISSN:00221260)

巻号頁・発行日

vol.65, no.5, pp.225-233, 2019 (Released:2019-12-19)

参考文献数

36

被引用文献数

1 7

---

Bioremediation may affect the ecological system around bioremediation sites. However, little is known about how microbial community structures change over time after the initial injection of degraders. In this study, we have assessed the ecological impact of bioaugmentation using metagenomic and metatranscriptomic approaches to remove trichlorinated ethylene/cis-dichloroethylene (TCE/cDCE) by Rhodococcus jostii strain RHA1 as an aerobic chemical compound degrader. Metagenomic analysis showed that the number of organisms belonging to the genus Rhodococcus, including strain RHA1, increased from 0.1% to 76.6% of the total microbial community on day 0 at the injection site. Subsequently, the populations of strain RHA1 and other TCE/cDCE-degrading bacteria gradually decreased over time, whereas the populations of the anaerobic dechlorinators Geobacter and Dehalococcoides increased at later stages. Metatranscriptomic analysis revealed a high expression of aromatic compound-degrading genes (bphA1-A4) in strain RHA1 after RHA1 injection. From these results, we concluded that the key dechlorinators of TCE/cDCE were mainly aerobic bacteria, such as RHA1, until day 1, after which the key dechlorinators changed to anaerobic bacteria, such as Geobacter and Dehalococcocides, after day 6 at the injection well. Based on the α-diversity, the richness levels of the microbial community were increased after injection of strain RHA1, and the microbial community composition had not been restored to that of the original composition during the 19 days after treatment. These results provide insights into the assessment of the ecological impact and bioaugmentation process of RHA1 at bioremediation sites.

著者

Kristian Daly Jennifer Kelly Andrew W. Moran Robert Bristow Iain S. Young Andrew R. Cossins David Bravo Soraya P. Shirazi-Beechey

出版者

Applied Microbiology, Molecular and Cellular Biosciences Research Foundation

雑誌

The Journal of General and Applied Microbiology (ISSN:00221260)

巻号頁・発行日

pp.2018.07.003, (Released:2018-11-09)

参考文献数

44

被引用文献数

12

---

Fish production is increasingly important to global food security. A major factor in maintaining health, productivity and welfare of farmed fish is the establishment and promotion of a stable and beneficial intestinal microbiota. Understanding the effects of factors such as host and environment on gut microbial community structure is essential for developing strategies for stimulating the establishment of a health-promoting gut-microbiota. We compared intestinal microbiota of common carp and rainbow trout, two fish with different dietary habits, sourced from various farm locations. There were distinct differences in the gut microbiota of carp and trout intestine. The microbiota of carp was dominated by Fusobacteriia and Gammaproteobacteria, while the trout microbiota consisted predominantly of Mollicutes and Betaproteobacteria. The majority of bacterial sequences clustered into a relatively low number of operational taxonomic units (OTUs) revealing a comparatively simple microbiota, with Cetobacterium, Aeromonas and Mycoplasma being highly abundant. Within each species, fish from different facilities were found to have markedly similar predominant bacterial populations despite distinctly different rearing environments, demonstrating intra-species uniformity and significant influence of host selectivity. This study demonstrates that in fish the host species imparts substantial impact in shaping the community structure of the intestinal microbiota.

著者

Gumpanat Mahipant Junichi Kato Naoya Kataoka Alisa S. Vangnai

出版者

Applied Microbiology, Molecular and Cellular Biosciences Research Foundation

雑誌

The Journal of General and Applied Microbiology (ISSN:00221260)

巻号頁・発行日

pp.2018.06.001, (Released:2018-11-27)

参考文献数

49

被引用文献数

4

---

Given their applicability in genetic engineering, undomesticated Bacillus strains are extensively used as non-natural hosts for chemical production due to their high tolerance of toxic substrates or products. However, they are difficult to genomically modify due to their low transformation efficiencies. In this study, the Bacillus-E. coli shuttle vector pHY300PLK, which is widely used in gram-positive bacteria, was adopted for genome integration in organic solvent-tolerant Bacillus isolates. The Bacillus-replicative vector was used to deliver homologous recombinant DNA and propagate itself inside the host cell, increasing the likelihood of genome integration of the recombinant DNA. Then, the unintegrated vectors were cured by cell cultivation in antibiotic-free medium with facilitation of nickel ions. The developed protocol was successfully demonstrated and validated by the disruption of amyE gene in B. subtilis 168. With an improved clonal selection protocol, the probability of clonal selection of the amyE::cat genome-integrated mutants was increased up to 42.0 ± 10.2%. Genome integration in undomesticated, organic solvent tolerant Bacillus strains was also successfully demonstrated with amyE as well as proB gene creating the gene-disrupted mutants with the corresponding phenotype and genotype. Not only was this technique effectively applied to several strains of undomesticated B. subtilis, but it was also successfully applied to B. cereus. This study validates the possibility of the application of Bacillus-replicative vector as well as the developed protocol in a variety of genome modification of undomesticated Bacillus species.

著者

Xiaochi Zhang Tomomi Nakahara Shinji Murase Hideaki Nakata Tetsushi Inoue Toshiaki Kudo

出版者

Applied Microbiology, Molecular and Cellular Biosciences Research Foundation

雑誌

The Journal of General and Applied Microbiology (ISSN:00221260)

巻号頁・発行日

vol.59, no.1, pp.1-10, 2013 (Released:2013-03-22)

参考文献数

20

被引用文献数

1 22

---

Various aerobic culturable bacteria (1,133 isolates) were isolated from the gut of Apostichopus japonicus (black adult, green adult, black small, green small, black juvenile, and green juvenile sea cucumbers) and from the sea sediment and the seawater using different culture conditions and without enrichment culture. By molecular analysis of partial 16S rRNA gene sequences of 231 isolates, they were tentatively affiliated with 53 described species in the phyla Firmicutes (42 species), Proteobacteria (9 species) and Actinobacteria (2 species). Eighteen species were often found among the intestines and the sea sediment. High diversity was observed in the genus Bacillus (20 species), Oceanobacillus and Virgibaillus but there were no isolates affiliated to members of the genus Vibrio, well-known sea pathogens. There were no clear differences in the bacterial communities among the hosts varied in size and color. Most isolates showed various polysaccharide degradation activities, suggesting their possible contributions in the digestion of organic matters in the gut.

著者

Yuji Oikawa Yui Sinmura Hikari Ishizaka Ryota Midorikawa Jun Kawamoto Tatsuo Kurihara Chiaki Kato Koki Horikoshi Hideyuki Tamegai

出版者

Applied Microbiology, Molecular and Cellular Biosciences Research Foundation

雑誌

The Journal of General and Applied Microbiology (ISSN:00221260)

巻号頁・発行日

vol.61, no.1, pp.10-14, 2015-02-27 (Released:2015-03-31)

参考文献数

24

被引用文献数

3

---

This article was retracted.

著者

Akane Nojiri Shinjiro Ogita Yasuhiro Isogai Hiromi Nishida

出版者

Applied Microbiology, Molecular and Cellular Biosciences Research Foundation

雑誌

The Journal of General and Applied Microbiology (ISSN:00221260)

巻号頁・発行日

vol.61, no.2, pp.44-49, 2015-04-30 (Released:2015-05-27)

参考文献数

18

被引用文献数

1

---

This article was retracted.

著者

Anil Kumar Pinnaka Naga Radha Srinivas Tanuku Sasikala Chintalapati Venkata Ramana Chintalapati Süling Jorg Imhoff Johannes

出版者

Applied Microbiology, Molecular and Cellular Biosciences Research Foundation

雑誌

The Journal of General and Applied Microbiology (ISSN:00221260)

巻号頁・発行日

vol.55, no.2, pp.163-169, 2009

被引用文献数

18

---

A green sulfur bacterium, strain JAGS6<Sup>T</Sup> was isolated from a marine aquaculture pond located near Kakinada on the east coast of India. Cells of strain JAGS6<Sup>T</Sup> were Gram-negative, non-motile, coccoid, 1-1.2 µm in diameter, with prosthecae. Phylogenetic analysis on the basis of 16S rRNA gene sequences showed that strain JAGS6<Sup>T</Sup> clusters with members of the genus <I>Prosthecochlo</I><I>ris </I>and the sequence similarity with the nearest relative, <I>Prosthecochloris vibrioformis,</I> is 96.7%<I>. </I>Cultures of strain JAGS6<Sup>T</Sup> are green in color and the cells contain bacteriochlorophyll <I>c</I> and most likely carotenoids of the chlorobactene series as photosynthetic pigments. Strain JAGS6<Sup>T</Sup> is mesophilic, halotolerant (up to 7% NaCl) and is obligately phototrophic, utilizing sulfide but not thiosulfate as a photosynthetic electron donor. Sulfur globules are deposited outside the cells during oxidation of sulfide. On the basis of 16S rRNA gene sequence analysis and its morphological and physiological characteristics, strain JAGS6<Sup>T</Sup> is distinct from described species of the genus <I>Prosthecochloris </I>and we propose to describe it as a new species, <I>Prosthecochloris indica,</I> sp. nov. The type strain is JAGS6<Sup>T</Sup> (= JCM 13299<Sup>T </Sup>= ATCC BAA1214<Sup>T</Sup>).

著者

Tai-Yen Liu Shu-Hung Chu Gwo-Chyuan Shaw

出版者

Applied Microbiology, Molecular and Cellular Biosciences Research Foundation

雑誌

The Journal of General and Applied Microbiology (ISSN:00221260)

巻号頁・発行日

pp.2017.09.002, (Released:2018-03-19)

参考文献数

32

被引用文献数

6

著者

Masanori Horie Taisuke Koike Sakiko Sugino Aya Umeno Yasukazu Yoshida

出版者

Applied Microbiology, Molecular and Cellular Biosciences Research Foundation

雑誌

The Journal of General and Applied Microbiology (ISSN:00221260)

巻号頁・発行日

pp.2017.03.002, (Released:2017-12-08)

参考文献数

29

被引用文献数

14

---

The aim of this study was to determine the probiotic and the prebiotic-like properties of Bacillus subtilis BN, a spore-forming bacterium, also known as “natto-kin”, which is used for making the Japanese fermented food, natto. We used the spores and vegetative cells of this strain and compared their effects on the growth of lactobacilli. Culture supernatant from B. subtilis BN was added to a glucose-free MRS medium used to culture lactobacilli. When lactobacilli were cultured in the supernatant-containing medium, growth was improved. This effect resulted from the digestion of starch by amylase, which was secreted by B. subtilis. Moreover, improved amylase-independent growth was also observed. Co-culture with B. subtilis improved the growth of lactobacilli, and this effect was only observed with vegetative cells; spores did not improve the growth of lactobacilli. This effect on growth was lost upon heat treatment of the vegetative cells. These results suggest that the surface protein of B. subtilis BN vegetative cells participates in the improved growth effect of lactobacilli. It is possible that B. subtilis BN could improve the intestinal flora. In addition, B. subtilis BN inhibited the growth of Salmonella enterica. Thus, it was shown that B. subtilis BN has both a probiotic and prebiotic potential. This is the first study demonstrating the selective growth improvement of indigenous intestinal lactobacilli using B. subtilis BN.

著者

NORIYUKI FUKUNAGA MASATO WADA MAMORU HONJO YUHKO SETAISHI NAOKI HAYASHINAKA YASUHIRO TAKADA JIRO NISHIKAWA

出版者

公益財団法人 応用微生物学・分子細胞生物学研究奨励会

雑誌

The Journal of General and Applied Microbiology (ISSN:00221260)

巻号頁・発行日

vol.41, no.3, pp.191-205, 1995 (Released:2006-08-22)

参考文献数

35

被引用文献数

1 10

---

A Gram-negative, aerobic bacterium isolated from the bottom layer of Lake Vanda, Antarctica, can grow in a synthetic medium containing biotin as a growth factor. The lipid and fatty acid compositions of the cells grown in the fatty acid-free medium were analyzed. Phosphatidylethanolamine, phosphatidylglycerol and wax esters were identified as major components of the chloroform-methanol extractable lipids. Palmitoleic and oleic acids comprised more than 90% of the total fatty acid of the lipids when the bacterium was grown at low temperature (5°C). Increasing the growth temperature induced an increase in the average fatty acyl chain length of the phospholipids and a decrease in the unsaturation degree of the fatty acyl chain of the wax esters. Increasing the NaCl concentration in the medium also induced an increase in the average fatty acyl chain length of the phospholipids. The effects of temperature and NaCl were compared further at the level of phospholipid molecular species. The sn-2 position of phosphatidylethanolamine and the sn-1 position of phosphatidylglycerol were the most sensitive sites to changes of temperature and NaCl concentration, respectively. An aerobic desaturase system was demonstrated to be the only pathway for unsaturated fatty acid synthesis in this bacterium.

著者

Mayuko Hori Shyunsuke Oka Yoshimi Sugie Hokuto Ohtsuka Hirofumi Aiba

出版者

公益財団法人 応用微生物学・分子細胞生物学研究奨励会

雑誌

The Journal of General and Applied Microbiology (ISSN:00221260)

巻号頁・発行日

vol.63, no.1, pp.44-50, 2017 (Released:2017-03-17)

参考文献数

28

被引用文献数

3

---

Two-component signal transduction systems (TCS), that are also referred to as His to Asp phosphorelay systems, are involved in widespread cellular responses to diverse signals from bacteria to plants. Previously, we succeeded in reconstructing a cyanobacterial photo-perception system in Escherichia coli by employing a CcaS-CcaR two-component system from Nostoc punctiforme. In this study, we have added a photo-responsive ability to ArcB-ArcA (anoxic redox control) TCS of E. coli by fusing a cyanobacterial photoreceptor domain of CcaS with an intracellular histidine kinase (HK) domain of ArcB. For this, we constructed several chimeric HKs between CcaS and ArcB and found that one chimeric HK, named ArcaS9, has a photo-responsive ability. When ArcaS9 was expressed with an ArcA response regulator in E. coli expressing phycocyanobilin (PCB)-producing enzymes, the expression of sdh, a target gene of ArcB-ArcA TCS was regulated in a light-color-dependent manner. Thus we succeeded in endowing E. coli HK with a photo-responsive ability. This provides an insight into how the sensing ability of HK can be manipulated by a chimeric construct.

著者

Shingo Suzuki Akihiro Kaidow Takuma Meya Anri Masuya Takashi Shiina

出版者

公益財団法人 応用微生物学・分子細胞生物学研究奨励会

雑誌

The Journal of General and Applied Microbiology (ISSN:00221260)

巻号頁・発行日

vol.63, no.1, pp.22-27, 2017 (Released:2017-03-17)

参考文献数

38

被引用文献数

2

---

Many significant gene mutations in E. coli have contributed to the development of genetics. Among these, a commonly used recA mutation, Δ(srl–recA)306 has been sequenced by a next-generation sequencer combined with a long PCR. An original report described that Δ(srl–recA)306 cells were deleted from srlR to recA genes in their genome. The next-generation sequencer enables more accurate details to be determined. We ask whether both surrounding genes from hypF to norV for srlR and alaS for recA is there first. The long PCR was carried out with primers, norR and alaS, and amplified DNA fragments differed in length from wild to Δ(srl–recA)306 cells, suggesting that an entire Δ(srl–recA)306 mutation was included. Sequences of those DNA fragments indicated that 9147 bp, from srlR to recA including 10 genes, were replaced by a Tn10 DNA sequence. Junction points at both srlR-Tn10 and Tn10-recA were determined precisely. The results indicate that the first 97% of recA gene sequences were lost with a downstream recX gene remaining intact. The phenotypic difference between Δ(srl–recA)306 and ΔrecA::Km is discussed.

著者

Jinqiang Huang Yongjuan Li Yuzhu Luo

出版者

公益財団法人 応用微生物学・分子細胞生物学研究奨励会

雑誌

The Journal of General and Applied Microbiology (ISSN:00221260)

巻号頁・発行日

pp.2016.08.003, (Released:2017-02-24)

参考文献数

38

被引用文献数

17

---

The rumen microbiome plays a vital role in ruminant nutrition and health, and its community is affected by environmental factors. However, little is known about the rumen bacterial community of ruminants living in the special ecological environment of the Qinghai-Tibetan Plateau (QTP) of China. The objectives of this study were to investigate the rumen bacterial community of the typical plateau sheep (Tibetan sheep, TS, and Gansu alpine fine-wool sheep, GS) grazing on the QTP, using 16S rRNA gene sequence analysis, and to evaluate the relationship between the rumen bacterial community and the QTP environment. A total of 116 sequences (201 clones) were examined and divided into 53 operational taxonomic units (OTUs) in the TS library and 46 OTUs in the GS library. Phylogenetic analysis showed that the sequences that belonged to the Firmicutes were the most predominant bacteria in both TS and GS libraries, representing 79.4% and 62.8% of the total clones, respectively. The remaining sequences belonged to Bacteroidetes, Proteobacteria, Actinobacteria, or were unclassified bacteria. Sequence analysis revealed that the TS and GS rumens harbored many novel sequences associated with uncultured bacteria that accounted for 63.6% and 46.8% of the total clones, respectively. Comparison of the composition and diversity of the TS and GS rumen bacteria revealed few overlapping known bacteria between the two breeds, and a higher diversity in TS. The rumen bacteria of the plateau sheep showed higher percentages of bacteria that belonged to Firmicutes and novel species compared with the low-elevation sheep. The unique bacterial community in the plateau sheep rumens is perhaps one of the major reasons that they can adapt to the harsh plateau environment. These results can help identify the rumen bacterial community of the ruminants in the QTP, and provide bacteria resources and basic data to improve ruminant productivity.