著者

Takehisa Yano Hiromi Kubota Junya Hanai Jun Hitomi Hajime Tokuda

出版者

Japanese Society of Microbial Ecology / Japanese Society of Soil Microbiology / Taiwan Society of Microbial Ecology / Japanese Society of Plant Microbe Interactions / Japanese Society for Extremophiles

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

vol.28, no.1, pp.87-95, 2013 (Released:2013-03-12)

参考文献数

53

被引用文献数

11 49

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A comprehensive survey of microbial flora within pink biofilms in bathrooms was performed. Pink biofilms develop relatively rapidly in bathrooms, can be difficult to remove, and are quick to recur. Bacterium-sized cells were found to be predominant in 42 pink biofilms in Japan using a scanning electron microscope. Methylobacterium strains were detected from all samples in bathrooms by an isolation method. To explain this predominance, 14 biofilm samples were analyzed by fluorescence in situ hybridization. Methylobacterium was indicated to be the major genus in all biofilms. The isolated Methylobacterium survived after contact with 1.0% cleaning agents, including benzalkonium chloride for 24 h. Their tolerance did not differ under biofilm-like conditions on fiber reinforced plastics (FRP), a general material of bath tubs, floors, and walls. Also, the strains exhibited higher tolerance to desiccation than other isolated species on FRP. Some Methylobacterium survived and exhibited potential to grow after four weeks of desiccation without any nutrients. These specific characteristics could be a cause of their predominance in bathrooms, an environment with rapid flowing water, drying, low nutrients, and occasional exposure to cleaning agents.

著者

Shun Hashimoto Kohki Goto Pongdet Pyromyou Pongpan Songwattana Teerana Greetatorn Panlada Tittabutr Nantakorn Boonkerd Neung Teaumroong Toshiki Uchiumi

出版者

Japanese Society of Microbial Ecology / Japanese Society of Soil Microbiology / Taiwan Society of Microbial Ecology / Japanese Society of Plant Microbe Interactions / Japanese Society for Extremophiles

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

vol.35, no.3, pp.ME20041, 2020 (Released:2020-07-02)

参考文献数

20

被引用文献数

2

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The rhizobial type III secretion system secretes effector proteins into host plant cells, which may either promote or inhibit symbiosis with legumes. We herein demonstrated that the type III secretion system of Bradyrhizobium sp. SUTN9-2 obstructed symbiosis with Lotus japonicus Miyakojima, L. japonicus Gifu, and Lotus burttii. A mutant of SUTN9-2 that is unable to secrete effector proteins showed better nodulation and plant growth promotion than wild-type SUTN9-2 when paired with these Lotus spp. We propose that SUTN9-2 is a useful strain for understanding the mechanisms by which effector proteins obstruct symbiosis between Bradyrhizobium and Lotus spp.

著者

Tajul Islam Øivind Larsen Nils-Kåre Birkeland

出版者

Japanese Society of Microbial Ecology / Japanese Society of Soil Microbiology / Taiwan Society of Microbial Ecology / Japanese Society of Plant Microbe Interactions / Japanese Society for Extremophiles

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

vol.35, no.3, pp.ME20044, 2020 (Released:2020-06-12)

参考文献数

54

被引用文献数

6

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A novel cold-adapted methane-oxidizing bacterium, termed TFB, was isolated from the thermoglacial Arctic karst spring, Trollosen, located in the South Spitsbergen National Park (Norway). The source water is cold and extremely low in phosphate and nitrate. The isolate belongs to the Methylovulum genus of gammaproteobacterial methanotrophs, with the closest phylogenetic affiliation with Methylovulum miyakonense and Methylovulum psychrotolerans (96.2 and 96.1% 16S rRNA gene sequence similarities, respectively). TFB is a strict aerobe that only grows in the presence of methane or methanol. It fixes atmospheric nitrogen and contains Type I intracellular membranes. The growth temperature range was 2–22°C, with an optimum at 13–18°C. The functional genes pmoA, mxaF, and nifH were identified by PCR, whereas mmoX and cbbL were not. C16:1ω5c was identified as the major fatty acid constituent, at an amount (>49%) not previously found in any methanotrophs, and is likely to play a major role in cold adaptation. Strain TFB may be regarded as a new psychrotolerant or psychrophilic species within the genus Methylovulum. The recovery of this cold-adapted bacterium from a neutral Arctic thermal spring increases our knowledge of the diversity and adaptation of extremophilic gammaproteobacterial methanotrophs in the candidate family “Methylomonadaceae”.

著者

吉水 守 絵面 良男

出版者

Japanese Society of Microbial Ecology / Japanese Society of Soil Microbiology / Taiwan Society of Microbial Ecology / Japanese Society of Plant Microbe Interactions / Japanese Society for Extremophiles

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

vol.14, no.4, pp.269-275, 1999-12-31 (Released:2009-10-05)

参考文献数

25

被引用文献数

7 10

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Many bacteria producing anti-viral substances were isolated from the aquatic environment. Fish intestinal bacteria such as Aeromonas spp. and Vibrio spp. producing anti-viral substances were isolated from intestinal contents of masu salmon (Oncorhynchus masou), Japanese flounder (Paralichthys olivaceus) and barfin flounder (Verasper moseri). These Aeromonas strains produced anti-infectious hematopoietic necrosis virus (IHNV) substances and Vibrio strains showed anti-IHNV, Oncorhynchus masou virus (OMV) and barfin flounder nervous necrosis virus (BF-NNV) activities. When Aeromonas spp. strains M-26 and M-38 were mixed with food pellets and fed to rainbow trout (O. mykiss) and masu salmon, both bacteria became dominant in the intestinal microflora and anti-IHNV activity was observed in homogenates of intestinal contents. These rainbow trout and masu salmon fed the Aeromonas spp. showed more resistance to the artificial IHNV challenge test. Barfin flounder fed Vibrio sp. strain 2IF6a with Altemia salina showed the anti-OMV and BF-NNV activities in the intestinal contents. Larvae fed the Vibrio sp. showed a higher survival rate than the fish cultured using the virus free sea water.

著者

Shohei Kusakabe Nahoko Higasitani Takakazu Kaneko Michiko Yasuda Hiroki Miwa Shin Okazaki Kazuhiko Saeki Atsushi Higashitani Shusei Sato

出版者

Japanese Society of Microbial Ecology / Japanese Society of Soil Microbiology / Taiwan Society of Microbial Ecology / Japanese Society of Plant Microbe Interactions / Japanese Society for Extremophiles

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

vol.35, no.1, pp.ME19141, 2020 (Released:2020-02-20)

参考文献数

65

被引用文献数

21

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Bradyrhizobium elkanii, a rhizobium with a relatively wide host range, possesses a functional type III secretion system (T3SS) that is involved in symbiotic incompatibility against Rj4-genotype soybean (Glycine max) and some accessions of mung bean (Vigna radiata). To expand our knowledge on the T3SS-mediated partner selection mechanism in the symbiotic legume-rhizobia association, we inoculated three Lotus experimental accessions with wild-type and T3SS-mutant strains of B. elkanii USDA61. Different responses were induced by T3SS in a host genotype-dependent manner. Lotus japonicus Gifu inhibited infection; L. burttii allowed infection, but inhibited nodule maturation at the post-infection stage; and L. burttii and L. japonicus MG-20 both displayed a nodule early senescence-like response. By conducting inoculation tests with mutants of previously reported and newly identified effector protein genes of B. elkanii USDA61, we identified NopF as the effector protein triggering the inhibition of infection, and NopM as the effector protein triggering the nodule early senescence–like response. Consistent with these results, the B. elkanii USDA61 gene for NopF introduced into the Lotus symbiont Mesorhizobium japonicum induced infection inhibition in L. japonicus Gifu, but did not induce any response in L. burttii or L. japonicus MG-20. These results suggest that Lotus accessions possess at least three checkpoints to eliminate unfavorable symbionts, including the post-infection stage, by recognizing different T3SS effector proteins at each checkpoint.

著者

Akira Hashimoto-Gotoh Koichi Kitao Takayuki Miyazawa

出版者

Japanese Society of Microbial Ecology / Japanese Society of Soil Microbiology / Taiwan Society of Microbial Ecology / Japanese Society of Plant Microbe Interactions / Japanese Society for Extremophiles

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

vol.35, no.1, pp.ME19130, 2020 (Released:2020-01-23)

参考文献数

62

被引用文献数

5

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MicroRNAs (miRNAs) are a group of small non-coding RNAs that suppress the expression of target mRNAs. The seed sequence of miRNA plays a crucial role in recognizing the 3′-untranslated region of the target mRNA. Cells infected with a simian foamy virus (SFV) isolated from an African green monkey (Chlorocebus aethiops) (SFVcae) showed high expression levels of viral miRNAs encoded in the long terminal repeat of SFVcae. In the present study, we investigated the roles and expression of miRNAs derived from an SFV isolated from a Japanese macaque (Macaca fuscata) (SFVmfu) using next-generation sequencing technologies. The results obtained showed that SFVmfu also expressed viral miRNAs; however, the seed sequences of most miRNAs derived from SFVmfu differed from those reported previously from SFVcae. Cells persistently infected with SFVmfu strongly expressed an miRNA with the same seed sequence as the miR-1 microRNA precursor family. Luciferase reporter assays indicated that this miRNA down-regulates the expression of adenylyl cyclase-associated protein 1, which is up-regulated in several solid tumors. The present results suggest that SFVmfu utilizes viral miRNAs to establish long-term co-existence with the Japanese macaque.

著者

Rebeca Padilla-Reynaud Anne-Marie Simao-Beaunoir Sylvain Lerat Mark A. Bernards Carole Beaulieu

出版者

Japanese Society of Microbial Ecology / Japanese Society of Soil Microbiology / Taiwan Society of Microbial Ecology / Japanese Society of Plant Microbe Interactions / Japanese Society for Extremophiles

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

pp.ME15034, (Released:2015-09-01)

被引用文献数

11 23

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Suberin, a major constituent of the potato periderm, is known to promote the production of thaxtomins, the key virulence factors of the common scab-causing agent Streptomyces scabiei. In the present study, we speculated that suberin affected the production of glycosyl hydrolases, such as cellulases, by S. scabiei, and demonstrated that suberin promoted glycosyl hydrolase activity when added to cellulose-, xylan-, or lichenin-containing media. Furthermore, secretome analyses revealed that the addition of suberin to a cellulose-containing medium increased the production of glycosyl hydrolases. For example, the production of 13 out of the 14 cellulases produced by S. scabiei in cellulose-containing medium was stimulated by the presence of suberin. In most cases, the transcription of the corresponding cellulase-encoding genes was also markedly increased when the bacterium was grown in the presence of suberin and cellulose. The level of a subtilase-like protease inhibitor was markedly decreased by the presence of suberin. We proposed a model for the onset of S. scabiei virulence mechanisms by both cellulose and suberin, the main degradation product of cellulose that acts as an inducer of thaxtomin biosynthetic genes, and suberin promoting the biosynthesis of secondary metabolites including thaxtomins.

著者

Hao Zheng Carsten Dietrich Claire L. Thompson Katja Meuser Andreas Brune

出版者

Japanese Society of Microbial Ecology / Japanese Society of Soil Microbiology / Taiwan Society of Microbial Ecology / Japanese Society of Plant Microbe Interactions / Japanese Society for Extremophiles

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

pp.ME14169, (Released:2015-02-26)

被引用文献数

16 29

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The gut microbiota of many phylogenetically lower termites is dominated by the cellulolytic flagellates of the genus Trichonympha, which are consistently associated with bacterial symbionts. In the case of Endomicrobia, an unusual lineage of endosymbionts of the Elusimicrobia phylum that is also present in other gut flagellates, previous studies have documented strict host specificity, leading to the cospeciation of “Candidatus Endomicrobium trichonymphae” with their respective flagellate hosts. However, it currently remains unclear whether one Trichonympha species is capable of harboring more than one Endomicrobia phylotype. In the present study, we selected single Trichonympha cells from the guts of Zootermopsis nevadensis and Reticulitermes santonensis and characterized their Endomicrobia populations based on internal transcribed spacer (ITS) region sequences. We found that each host cell harbored a homogeneous population of symbionts that were specific to their respective host species, but phylogenetically distinct between each host lineage, corroborating cospeciation being caused by vertical inheritance. The experimental design of the present study also allowed for the identification of an unexpectedly large amount of tag-switching between samples, which indicated that any high-resolution analysis of microbial community structures using the pyrosequencing technique has to be interpreted with great caution.

著者

Branko Velimirov

出版者

Japanese Society of Microbial Ecology / Japanese Society of Soil Microbiology / Taiwan Society of Microbial Ecology / Japanese Society of Plant Microbe Interactions / Japanese Society for Extremophiles

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

vol.16, no.2, pp.67-77, 2001 (Released:2001-07-16)

参考文献数

66

被引用文献数

38 61

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Very small forms of bacteria have been reported from marine and freshwater systems as well as from soils, subsurface terrestrial environments' and more recently from samples of kidney stones. Also, such small cells could be obtained in the laboratory during starvation experiments, indicating that bacteria which survive periods of nutrient deprivation manifest a decrease of cell size. Even though the various reports brought about poorly defined designations for small bacteria, they have stimulated the discussion on how small a living bacterium could be. The information derived from the literature concerning starvation forms, ultramicrobacteria and nanobacteria is analysed in the light of own field and laboratory observations. It could be shown that despite conceptual shortcomings and problems with definitions of what is meant by "small", starvation forms and ultramicrobacteria are clearly distinguishable according to physiological characteristics, which could not be achieved for nanobacteria or nanobes. Furthermore, it is documented that ultramicrobacteria are not the smallest procaryotes and that the size of bacterial starvation forms are much closer to the calculated minimal sizes required to ensure independent viable life. A bacterial cell which is growing and dividing needs to be large enough to accommodate DNA and RNA, enzymes for replication transcription and translation, solvent for ubstances as well as a minimum set of proteins and plasamtic space to run the operations. Many authors assume that this requires a cell with a diameter not smaller than 200 nm and with a volume between 0.014 and 0.06 μm3. Most cells with diameters equal or below 0.2 μm are rods while cocci are numerically of minor importance in natural aquatic systems. It seems that the rod morphotype has more potential to produce viable cells with minimal volumes than spherical morhotypes. This supports the assumption that not only size but also cell shape is important to achieve functional minimum cell volumes. Many cell parameters can be estimated with relatively high precision, but one should remember that absolute calibration is still not possible. Even if we assume that there are errors involved in most biometric measurements, there is still a trend which indicates that rod shaped cells can function with diameters below 0.2 μm and cell volumes well below 0.02 μm3. Such dimensions could be an indication that the lower size limit of a viable bacterium may be close to the size of the smallest hypothetical living cell, indicating that there is still more to know about the minimal required cell components allowing a bacterium the remain viable.