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Jorquera MA, Maruyama F, Ogram AV, Navarrete OU, Lagos LM, Inostroza NG, Acuña JJ, Rilling JI, de La Luz Mora M. Erratum to: Rhizobacterial Community Structures Associated with Native Plants Grown in Chilean Extreme Environments. MICROBIAL ECOLOGY 2017; 73:253. [PMID: 27538874 DOI: 10.1007/s00248-016-0830-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
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Maruyama F, Ueki S. Evolution and Phylogeny of Large DNA Viruses, Mimiviridae and Phycodnaviridae Including Newly Characterized Heterosigma akashiwo Virus. Front Microbiol 2016; 7:1942. [PMID: 27965659 PMCID: PMC5127864 DOI: 10.3389/fmicb.2016.01942] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Accepted: 11/18/2016] [Indexed: 11/13/2022] Open
Abstract
Nucleocytoplasmic DNA viruses are a large group of viruses that harbor double-stranded DNA genomes with sizes of several 100 kbp, challenging the traditional concept of viruses as small, simple ‘organisms at the edge of life.’ The most intriguing questions about them may be their origin and evolution, which have yielded the variety we see today. Specifically, the phyletic relationship between two giant dsDNA virus families that are presumed to be close, Mimiviridae, which infect Acanthamoeba, and Phycodnaviridae, which infect algae, is still obscure and needs to be clarified by in-depth analysis. Here, we studied Mimiviridae–Phycodnaviridae phylogeny including the newly identified Heterosigma akashiwo virus strain HaV53. Gene-to-gene comparison of HaV53 with other giant dsDNA viruses showed that only a small proportion of HaV53 genes show similarities with the others, revealing its uniqueness among Phycodnaviridae. Phylogenetic/genomic analysis of Phycodnaviridae including HaV53 revealed that the family can be classified into four distinctive subfamilies, namely, Megaviridae (Mimivirus-like), Chlorovirus-type, and Coccolitho/Phaeovirus-type groups, and HaV53 independent of the other three groups. Several orthologs found in specific subfamilies while absent from the others were identified, providing potential family marker genes. Finally, reconstruction of the evolutionary history of Phycodnaviridae and Mimiviridae revealed that these viruses are descended from a common ancestor with a small set of genes and reached their current diversity by differentially acquiring gene sets during the course of evolution. Our study illustrates the phylogeny and evolution of Mimiviridae–Phycodnaviridae and proposes classifications that better represent phyletic relationships among the family members.
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Kulkarni T, Aikawa C, Nozawa T, Murase K, Maruyama F, Nakagawa I. DNA-based culture-independent analysis detects the presence of group a streptococcus in throat samples from healthy adults in Japan. BMC Microbiol 2016; 16:237. [PMID: 27724855 PMCID: PMC5057481 DOI: 10.1186/s12866-016-0858-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 10/01/2016] [Indexed: 12/11/2022] Open
Abstract
Background Group A Streptococcus (GAS; Streptococcus pyogenes) causes a range of mild to severe infections in humans. It can also colonize healthy persons asymptomatically. Therefore, it is important to study GAS carriage in healthy populations, as carriage of it might lead to subsequent disease manifestation, clonal spread in the community, and/or diversification of the organism. Throat swab culture is the gold standard method for GAS detection. Advanced culture-independent methods provide rapid and efficient detection of microorganisms directly from clinical samples. We investigated the presence of GAS in throat swab samples from healthy adults in Japan using culture-dependent and culture-independent methods. Results Two throat swab samples were collected from 148 healthy volunteers. One was cultured on selective medium, while total DNA extracted from the other was polymerase chain reaction (PCR) amplified with two GAS-specific primer pairs: one was a newly designed 16S rRNA-specific primer pair, the other a previously described V-Na+-ATPase primer pair. Although only 5 (3.4 %) of the 148 samples were GAS-positive by the culture-dependent method, 146 (98.6 %) were positive for the presence of GAS DNA by the culture-independent method. To obtain serotype information by emm typing, we performed nested PCR using newly designed emm primers. We detected the four different emm types in 25 (16.9 %) samples, and these differed from the common emm types associated with GAS associated diseases in Japan. The different emm types detected in the healthy volunteers indicate that the presence of unique emm types might be associated with GAS carriage. Conclusions Our results suggest that culture-independent methods should be considered for profiling GAS in the healthy hosts, with a view to obtaining better understanding of these organisms. The GAS-specific primers (16S rRNA and V-Na+-ATPase) used in this study can be used to estimate the maximum potential GAS carriage in people. Electronic supplementary material The online version of this article (doi:10.1186/s12866-016-0858-5) contains supplementary material, which is available to authorized users.
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Jorquera MA, Maruyama F, Ogram AV, Navarrete OU, Lagos LM, Inostroza NG, Acuña JJ, Rilling JI, de La Luz Mora M. Rhizobacterial Community Structures Associated with Native Plants Grown in Chilean Extreme Environments. MICROBIAL ECOLOGY 2016; 72:633-646. [PMID: 27406732 DOI: 10.1007/s00248-016-0813-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 06/29/2016] [Indexed: 06/06/2023]
Abstract
Chile is topographically and climatically diverse, with a wide array of diverse undisturbed ecosystems that include native plants that are highly adapted to local conditions. However, our understanding of the diversity, activity, and role of rhizobacteria associated with natural vegetation in undisturbed Chilean extreme ecosystems is very poor. In the present study, the combination of denaturing gradient gel electrophoresis and 454-pyrosequencing approaches was used to describe the rhizobacterial community structures of native plants grown in three representative Chilean extreme environments: Atacama Desert (ATA), Andes Mountains (AND), and Antarctic (ANT). Both molecular approaches revealed the presence of Proteobacteria, Bacteroidetes, and Actinobacteria as the dominant phyla in the rhizospheres of native plants. Lower numbers of operational taxonomic units (OTUs) were observed in rhizosphere soils from ATA compared with AND and ANT. Both approaches also showed differences in rhizobacterial community structures between extreme environments and between plant species. The differences among plant species grown in the same environment were attributed to the higher relative abundance of classes Gammaproteobacteria and Alphaproteobacteria. However, further studies are needed to determine which environmental factors regulate the structures of rhizobacterial communities, and how (or if) specific bacterial groups may contribute to the growth and survival of native plants in each Chilean extreme environments.
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Tohya M, Watanabe T, Maruyama F, Arai S, Ota A, Athey TBT, Fittipaldi N, Nakagawa I, Sekizaki T. Comparative Genome Analyses of Streptococcus suis Isolates from Endocarditis Demonstrate Persistence of Dual Phenotypic Clones. PLoS One 2016; 11:e0159558. [PMID: 27433935 PMCID: PMC4951133 DOI: 10.1371/journal.pone.0159558] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 07/04/2016] [Indexed: 11/19/2022] Open
Abstract
Many bacterial species coexist in the same niche as heterogeneous clones with different phenotypes; however, understanding of infectious diseases by polyphenotypic bacteria is still limited. In the present study, encapsulation in isolates of the porcine pathogen Streptococcus suis from persistent endocarditis lesions was examined. Coexistence of both encapsulated and unencapsulated S. suis isolates was found in 26 out of 59 endocarditis samples. The isolates were serotype 2, and belonged to two different sequence types (STs), ST1 and ST28. The genomes of each of the 26 pairs of encapsulated and unencapsulated isolates from the 26 samples were sequenced. The data showed that each pair of isolates had one or more unique nonsynonymous mutations in the cps gene, and the encapsulated and unencapsulated isolates from the same samples were closest to each other. Pairwise comparisons of the sequences of cps genes in 7 pairs of encapsulated and unencapsulated isolates identified insertion/deletions (indels) ranging from one to 104 bp in different cps genes of unencapsulated isolates. Capsule expression was restored in a subset of unencapsulated isolates by complementation in trans with cps expression vectors. Examination of gene content common to isolates indicated that mutation frequency was higher in ST28 pairs than in ST1 pairs. Genes within mobile genetic elements were mutation hot spots among ST28 isolates. Taken all together, our results demonstrate the coexistence of dual phenotype (encapsulated and unencapsulated) bacterial clones and suggest that the dual phenotypes arose independently in each farm by means of spontaneous mutations in cps genes.
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Kubota T, Kobayashi T, Nunoura T, Maruyama F, Deguchi S. Enantioselective Utilization of D-Amino Acids by Deep-Sea Microorganisms. Front Microbiol 2016; 7:511. [PMID: 27148200 PMCID: PMC4836201 DOI: 10.3389/fmicb.2016.00511] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 03/29/2016] [Indexed: 12/27/2022] Open
Abstract
Microorganisms that utilize various D-amino acids (DAAs) were successfully isolated from deep-sea sediments. The isolates were phylogenetically assigned to Alphaproteobacteria, Gammmaproteobacteria, and Bacilli. Some of the isolates exhibited high enantioselective degradation activities to various DAAs. In particular, the Alphaproteobacteria Nautella sp. strain A04V exhibited robust growth in minimal medium supplemented with D-Val as a sole carbon and nitrogen source, whereas its growth was poor on minimal medium supplemented with L-Val instead of D-Val. Its growth was facilitated most when racemic mixtures of valine were used. In contrast, the Nautella strains isolated from shallow-sea grew only with L-Val. No significant differences were found among the strains in the genome sequences including genes possibly related to DAA metabolisms.
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Tajima N, Saitoh K, Sato S, Maruyama F, Ichinomiya M, Yoshikawa S, Kurokawa K, Ohta H, Tabata S, Kuwata A, Sato N. Sequencing and analysis of the complete organellar genomes of Parmales, a closely related group to Bacillariophyta (diatoms). Curr Genet 2016; 62:887-896. [DOI: 10.1007/s00294-016-0598-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Revised: 03/25/2016] [Accepted: 03/26/2016] [Indexed: 10/21/2022]
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Okada K, Natakuathung W, Na-Ubol M, Roobthaisong A, Wongboot W, Maruyama F, Nakagawa I, Chantaroj S, Hamada S. Characterization of 3 Megabase-Sized Circular Replicons from Vibrio cholerae. Emerg Infect Dis 2016; 21:1262-3. [PMID: 26079534 PMCID: PMC4480378 DOI: 10.3201/eid2107.141055] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Kato H, Mori H, Maruyama F, Toyoda A, Oshima K, Endo R, Fuchu G, Miyakoshi M, Dozono A, Ohtsubo Y, Nagata Y, Hattori M, Fujiyama A, Kurokawa K, Tsuda M. Time-series metagenomic analysis reveals robustness of soil microbiome against chemical disturbance. DNA Res 2015; 22:413-24. [PMID: 26428854 PMCID: PMC4675710 DOI: 10.1093/dnares/dsv023] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 09/03/2015] [Indexed: 11/18/2022] Open
Abstract
Soil microbial communities have great potential for bioremediation of recalcitrant aromatic compounds. However, it is unclear which taxa and genes in the communities, and how they contribute to the bioremediation in the polluted soils. To get clues about this fundamental question here, time-course (up to 24 weeks) metagenomic analysis of microbial community in a closed soil microcosm artificially polluted with four aromatic compounds, including phenanthrene, was conducted to investigate the changes in the community structures and gene pools. The pollution led to drastic changes in the community structures and the gene sets for pollutant degradation. Complete degradation of phenanthrene was strongly suggested to occur by the syntrophic metabolism by Mycobacterium and the most proliferating genus, Burkholderia. The community structure at Week 24 (∼12 weeks after disappearance of the pollutants) returned to the structure similar to that before pollution. Our time-course metagenomic analysis of phage genes strongly suggested the involvement of the ‘kill-the-winner’ phenomenon (i.e. phage predation of Burkholderia cells) for the returning of the microbial community structure. The pollution resulted in a decrease in taxonomic diversity and a drastic increase in diversity of gene pools in the communities, showing the functional redundancy and robustness of the communities against chemical disturbance.
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Ushida K, Tsuchida S, Ogura Y, Toyoda A, Maruyama F. Domestication and cereal feeding developed domestic pig-type intestinal microbiota in animals of suidae. Anim Sci J 2015; 87:835-41. [DOI: 10.1111/asj.12492] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Revised: 06/05/2015] [Accepted: 06/18/2015] [Indexed: 12/01/2022]
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Hamada M, Inada R, Oishi M, Maruyama F, Matsumoto T, Miki H, Iwamoto S. P-342 Standardized Technique of Laparoscopic Extralevator Abdominoperineal Excision (LAP-ELAPE). Ann Oncol 2015. [DOI: 10.1093/annonc/mdv233.336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Abe H, Aikawa C, Nakabachi A, Miyakoshi M, Maruyama F. [New insights from infection-specific gene expression network]. Nihon Saikingaku Zasshi 2015; 69:539-46. [PMID: 25186644 DOI: 10.3412/jsb.69.539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Most of our current knowledge about the gene regulation of pathogen comes from studies with in vitro conditions that mimic their host environments, revealing many types of virulence genes and their regulatory network. Recent advances in DNA sequencing and techniques for transcriptome analysis allow us to identify pathogenic genes specifically expressed in vivo. Analyses for gene expression of pathogens in response to the host environment, including immune response and change of bacterial flora during infection, provide clues to understanding the underlying events to establish the infectious diseases. Here, we would like to introduce next epoch-making ideas and concepts to understand the real picture of microbial infection through the recent works of gene regulation in host environments.
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Nonaka L, Maruyama F, Suzuki S, Masuda M. Novel macrolide-resistance genes, mef(C) and mph(G), carried by plasmids from Vibrio and Photobacterium isolated from sediment and seawater of a coastal aquaculture site. Lett Appl Microbiol 2015; 61:1-6. [PMID: 25765542 DOI: 10.1111/lam.12414] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 02/25/2015] [Accepted: 03/09/2015] [Indexed: 01/10/2023]
Abstract
UNLABELLED The aim of this study was to determine whether mef(C) and mph(G), originally found on the transferable multi-drug plasmid pAQU1 from Photobacterium damselae subsp. damselae isolated from seawater of a fish farm, are responsible for conferring macrolide resistance. Since these genes are localized head-to-tail on pAQU1 and only four nucleotides exist between them, the single- and combination-effect of these genes was examined. When mph(G) alone was introduced to Escherichia coli, the minimum inhibitory concentrations (MICs) against erythromycin, clarithromycin and azithromycin increased, whereas introduction of mef(C) alone did not influence macrolide susceptibility. Introduction of both mef(C) and mph(G) dramatically increased the MICs to the same three macrolides, i.e. >512 μg ml(-1) , >512 μg ml(-1) and 128 μg ml(-1) respectively. These results suggest that the macrolide phosphotransferase encoded by mph(G) is essential for macrolide resistance, while the efflux pump encoded by mef(C) is required for high-level macrolide resistance. The tandem-pair arrangements of the mef(C) and mph(G) genes were conserved on plasmids ranging in size from 240 to 350 kb of the 22 erythromycin-resistant strains belonging to Vibrio and Photobacterium obtained from the fish farm. Sixteen of 22 plasmids ranged in size from 300 to 350 kb. This is the first report of novel macrolide resistance genes originating from a marine bacterium. SIGNIFICANCE AND IMPACT OF THE STUDY In this study, mef(C) and mph(G) were found to be novel macrolide-resistance genes, and this is the first report of macrolide-resistance genes originating from a marine bacterium. These genes may be responsible for previously reported cases of the emergence of erythromycin-resistant bacteria in aquaculture sites by an unknown mechanism. The introduction of the tandem arrangement of the mef(C) and mph(G) genes in Escherichia coli increased the MICs to erythromycin, clarithromycin and azithromycin, suggesting a novel mechanism conferring high-level macrolide resistance via combined expression of the efflux pump and macrolide phosphotransferase.
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Nomoto R, Maruyama F, Ishida S, Tohya M, Sekizaki T, Osawa R. Reappraisal of the taxonomy of Streptococcus suis serotypes 20, 22 and 26: Streptococcus parasuis sp. nov. Int J Syst Evol Microbiol 2015; 65:438-443. [DOI: 10.1099/ijs.0.067116-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In order to clarify the taxonomic position of serotypes 20, 22 and 26 of
Streptococcus suis
, biochemical and molecular genetic studies were performed on isolates (SUT-7, SUT-286T, SUT-319, SUT-328 and SUT-380) reacted with specific antisera of serotypes 20, 22 or 26 from the saliva of healthy pigs as well as reference strains of serotypes 20, 22 and 26. Comparative recN gene sequencing showed high genetic relatedness among our isolates, but marked differences from the type strain
S. suis
NCTC 10234T, i.e. 74.8–75.7 % sequence similarity. The genomic relatedness between the isolates and other strains of species of the genus
Streptococcus
, including
S. suis,
was calculated using the average nucleotide identity values of whole genome sequences, which indicated that serotypes 20, 22 and 26 should be removed taxonomically from
S. suis
and treated as a novel genomic species. Comparative sequence analysis revealed 99.0–100 % sequence similarities for the 16S rRNA genes between the reference strains of serotypes 20, 22 and 26, and our isolates. Isolate STU-286T had relatively high 16S rRNA gene sequence similarity with
S. suis
NCTC 10234T (98.8 %). SUT-286T could be distinguished from
S. suis
and other closely related species of the genus
Streptococcus
using biochemical tests. Due to its phylogenetic and phenotypic similarities to
S. suis
we propose naming the novel species Streptococcus parasuis sp. nov., with SUT-286T ( = JCM 30273T = DSM 29126T) as the type strain.
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Shoji M, Takeshita T, Maruyama F, Inaba H, Imai K, Kawada-Matsuo M. [Recent advances in the field of oral bacteriology]. Nihon Saikingaku Zasshi 2015; 70:333-338. [PMID: 26028214 DOI: 10.3412/jsb.70.333] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The oral cavity is inhabited by more than 600 bacterial species; these species compete for nutrients or coexist in order to survive along with the indigenous population. Extreme conditions are prevalent in the oral cavity, and these conditions are influenced by our immunity and variations in nutrition, temperature, and pH. Pathogens that cause dental caries or periodontal disease can survive in these extreme environments; these pathogens are virulent and can cause several diseases. Therefore, research on oral bacteriology is warranted to analyze the virulence factors of these bacteria as well as to ascertain environmental stress responses, interactions between bacteria and human immunity, comparisons of bacterial genomes, and oral microflora. In this review, we provide new data in the fields of bacteriology, immunology, and genomics and describe recent advances in the field of oral bacteriology.
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Sawabe T, Ogura Y, Matsumura Y, Feng G, Amin AKMR, Mino S, Nakagawa S, Sawabe T, Kumar R, Fukui Y, Satomi M, Matsushima R, Thompson FL, Gomez Gil B, Christen R, Maruyama F, Kurokawa K, Hayashi T. Corrigendum: Updating the Vibrio clades defined by multilocus sequence phylogeny: proposal of eight new clades, and the description of Vibrio tritonius sp. nov. Front Microbiol 2014; 5:583. [PMID: 25406895 PMCID: PMC4219481 DOI: 10.3389/fmicb.2014.00583] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 10/16/2014] [Indexed: 11/21/2022] Open
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Maruyama N, Maruyama F, Takeuchi Y, Aikawa C, Izumi Y, Nakagawa I. Intraindividual variation in core microbiota in peri-implantitis and periodontitis. Sci Rep 2014; 4:6602. [PMID: 25308100 PMCID: PMC4194447 DOI: 10.1038/srep06602] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 09/19/2014] [Indexed: 01/01/2023] Open
Abstract
The oral microbiota change dramatically with each part of the oral cavity, even within the same mouth. Nevertheless, the microbiota associated with peri-implantitis and periodontitis have been considered the same. To improve our knowledge of the different communities of complex oral microbiota, we compared the microbial features between peri-implantitis and periodontitis in 20 patients with both diseases. Although the clinical symptoms of peri-implantitis were similar to those of periodontitis, the core microbiota of the diseases differed. Correlation analysis revealed the specific microbial co-occurrence patterns and found some of the species were associated with the clinical parameters in a disease-specific manner. The proportion of Prevotella nigrescens was significantly higher in peri-implantitis than in periodontitis, while the proportions of Peptostreptococcaceae sp. and Desulfomicrobium orale were significantly higher in periodontitis than in peri-implantitis. The severity of the peri-implantitis was also species-associated, including with an uncultured Treponema sp. that correlated to 4 clinical parameters. These results indicate that peri-implantitis and periodontitis are both polymicrobial infections with different causative pathogens. Our study provides a framework for the ecologically different bacterial communities between peri-implantitis and periodontitis, and it will be useful for further studies to understand the complex microbiota and pathogenic mechanisms of oral polymicrobial diseases.
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Haobam B, Nozawa T, Minowa-Nozawa A, Tanaka M, Oda S, Watanabe T, Aikawa C, Maruyama F, Nakagawa I. Rab17-mediated recycling endosomes contribute to autophagosome formation in response to Group A Streptococcus invasion. Cell Microbiol 2014; 16:1806-21. [PMID: 25052408 DOI: 10.1111/cmi.12329] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 06/04/2014] [Accepted: 06/25/2014] [Indexed: 01/21/2023]
Abstract
Autophagy plays a crucial role in host defence by facilitating the degradation of invading bacteria such as Group A Streptococcus (GAS). GAS-containing autophagosome-like vacuoles (GcAVs) form when GAS-targeting autophagic membranes entrap invading bacteria. However, the membrane origin and the precise molecular mechanism that underlies GcAV formation remain unclear. In this study, we found that Rab17 mediates the supply of membrane from recycling endosomes (REs) to GcAVs. We showed that GcAVs contain the RE marker transferrin receptor (TfR). Colocalization analyses demonstrated that Rab17 colocalized effectively with GcAV. Rab17 and TfR were visible as punctate structures attached to GcAVs and the Rab17-positive dots were recruited to the GAS-capturing membrane. Overexpression of Rab17 increased the TfR-positive GcAV content, whereas expression of the dominant-negative Rab17 form (Rab17 N132I) caused a decrease, thereby suggesting the involvement of Rab17 in RE-GcAV fusion. The efficiency of GcAV formation was lower in Rab17 N132I-overexpressing cells. Furthermore, knockdown of Rabex-5, the upstream activator of Rab17, reduced the GcAV formation efficiency. These results suggest that Rab17 and Rab17-mediated REs are involved in GcAV formation. This newly identified function of Rab17 in supplying membrane from REs to GcAVs demonstrates that RE functions as a primary membrane source during antibacterial autophagy.
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Segawa T, Ishii S, Ohte N, Akiyoshi A, Yamada A, Maruyama F, Li Z, Hongoh Y, Takeuchi N. The nitrogen cycle in cryoconites: naturally occurring nitrification-denitrification granules on a glacier. Environ Microbiol 2014; 16:3250-62. [DOI: 10.1111/1462-2920.12543] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 06/13/2014] [Indexed: 11/29/2022]
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Okada K, Na-Ubol M, Natakuathung W, Roobthaisong A, Maruyama F, Nakagawa I, Chantaroj S, Hamada S. Comparative genomic characterization of a Thailand-Myanmar isolate, MS6, of Vibrio cholerae O1 El Tor, which is phylogenetically related to a "US Gulf Coast" clone. PLoS One 2014; 9:e98120. [PMID: 24887199 PMCID: PMC4045137 DOI: 10.1371/journal.pone.0098120] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Accepted: 04/29/2014] [Indexed: 12/17/2022] Open
Abstract
Background The cholera outbreaks in Thailand during 2007–2010 were exclusively caused by the Vibrio cholerae O1 El Tor variant carrying the cholera toxin gene of the classical biotype. We previously isolated a V. cholerae O1 El Tor strain from a patient with diarrhea and designated it MS6. Multilocus sequence-typing analysis revealed that MS6 is most closely related to the U. S. Gulf Coast clone with the exception of two novel housekeeping genes. Methodology/Principal Findings The nucleotide sequence of the genome of MS6 was determined and compared with those of 26 V. cholerae strains isolated from clinical and environmental sources worldwide. We show here that the MS6 isolate is distantly related to the ongoing seventh pandemic V. cholerae O1 El Tor strains. These strains differ with respect to polymorphisms in housekeeping genes, seventh pandemic group-specific markers, CTX phages, two genes encoding predicted transmembrane proteins, the presence of metY (MS6_A0927) or hchA/luxR in a highly conserved region of the V. cholerae O1 serogroup, and a superintegron (SI). We found that V. cholerae species carry either hchA/luxR or metY and that the V. cholerae O1 clade commonly possesses hchA/luxR, except for MS6 and U. S. Gulf Coast strains. These findings illuminate the evolutionary relationships among V. cholerae O1 strains. Moreover, the MS6 SI carries a quinolone-resistance gene cassette, which was closely related with those present in plasmid-borne integrons of other gram-negative bacteria. Conclusions/Significance Phylogenetic analysis reveals that MS6 is most closely related to a U. S. Gulf Coast clone, indicating their divergence before that of the El Tor biotype strains from a common V. cholerae O1 ancestor. We propose that MS6 serves as an environmental aquatic reservoir of V. cholerae O1.
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Nonaka L, Maruyama F, Onishi Y, Kobayashi T, Ogura Y, Hayashi T, Suzuki S, Masuda M. Various pAQU plasmids possibly contribute to disseminate tetracycline resistance gene tet(M) among marine bacterial community. Front Microbiol 2014; 5:152. [PMID: 24860553 PMCID: PMC4026752 DOI: 10.3389/fmicb.2014.00152] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 03/21/2014] [Indexed: 11/13/2022] Open
Abstract
Emergence of antibiotic-resistant bacteria in the aquaculture environment is a significant problem for disease control of cultured fish as well as in human public health. Conjugative mobile genetic elements (MGEs) are involved in dissemination of antibiotic resistance genes (ARGs) among marine bacteria. In the present study, we first designed a PCR targeting traI gene encoding essential relaxase for conjugation. By this new PCR, we demonstrated that five of 83 strains isolated from a coastal aquaculture site had traI-positive MGEs. While one of the five strains that belonged to Shewanella sp. was shown to have an integrative conjugative element of the SXT/R391 family (ICEVchMex-like), the MGEs of the other four strains of Vibrio spp. were shown to have the backbone structure similar to that of previously described in pAQU1. The backbone structure shared by the pAQU1-like plasmids in the four strains corresponded to a ~100-kbp highly conserved region required for replication, partition and conjugative transfer, suggesting that these plasmids constituted “pAQU group.” The pAQU group plasmids were shown to be capable of conjugative transfer of tet(M) and other ARGs from the Vibrio strains to E. coli. The pAQU group plasmid in one of the examined strains was designated as pAQU2, and its complete nucleotide sequence was determined and compared with that of pAQU1. The results revealed that pAQU2 contained fewer ARGs than pAQU1 did, and most of the ARGs in both of these plasmids were located in the similar region where multiple transposases were found, suggesting that the ARGs were introduced by several events of DNA transposition into an ancestral plasmid followed by drug selection in the aquaculture site. The results of the present study indicate that the “pAQU group” plasmids may play an important role in dissemination of ARGs in the marine environment.
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Tajima N, Sato S, Maruyama F, Kurokawa K, Ohta H, Tabata S, Sekine K, Moriyama T, Sato N. Analysis of the complete plastid genome of the unicellular red alga Porphyridium purpureum. JOURNAL OF PLANT RESEARCH 2014; 127:389-97. [PMID: 24595640 DOI: 10.1007/s10265-014-0627-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 01/05/2014] [Indexed: 05/11/2023]
Abstract
We determined the complete nucleotide sequence of the plastid genome of the unicellular marine red alga Porphyridium purpureum strain NIES 2140, belonging to the unsequenced class Porphyridiophyceae. The genome is a circular DNA composed of 217,694 bp with the GC content of 30.3%. Twenty-nine of the 224 protein-coding genes contain one or multiple intron(s). A group I intron was found in the rpl28 gene, whereas the other introns were group II introns. The P. purpureum plastid genome has one non-coding RNA (ncRNA) gene, 29 tRNA genes and two nonidentical ribosomal RNA operons. One rRNA operon has a tRNA(Ala)(UGC) gene between the rrs and the rrl genes, whereas another has a tRNA(Ile)(GAU) gene. Phylogenetic analyses suggest that the plastids of Heterokontophyta, Cryptophyta and Haptophyta originated from the subphylum Rhodophytina. The order of the genes in the ribosomal protein cluster of the P. purpureum plastid genome differs from that of other Rhodophyta and Chromalveolata. These results suggest that a large-scale rearrangement occurred in the plastid genome of P. purpureum after its separation from other Rhodophyta.
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Watanabe T, Nozawa T, Aikawa C, Amano A, Maruyama F, Nakagawa I. CRISPR regulation of intraspecies diversification by limiting IS transposition and intercellular recombination. Genome Biol Evol 2013; 5:1099-114. [PMID: 23661565 PMCID: PMC3698921 DOI: 10.1093/gbe/evt075] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Mobile genetic elements (MGEs) and genetic rearrangement are considered as major driving forces of bacterial diversification. Previous comparative genome analysis of Porphyromonas gingivalis, a pathogen related to periodontitis, implied such an important relationship. As a counterpart system to MGEs, clustered regularly interspaced short palindromic repeats (CRISPRs) in bacteria may be useful for genetic typing. We found that CRISPR typing could be a reasonable alternative to conventional methods for characterizing phylogenetic relationships among 60 highly diverse P. gingivalis isolates. Examination of genetic recombination along with multilocus sequence typing suggests the importance of such events between different isolates. MGEs appear to be strategically located at the breakpoint gaps of complicated genome rearrangements. Of these MGEs, insertion sequences (ISs) were found most frequently. CRISPR analysis identified 2,150 spacers that were clustered into 1,187 unique ones. Most of these spacers exhibited no significant nucleotide similarity to known sequences (97.6%: 1,158/1,187). Surprisingly, CRISPR spacers exhibiting high nucleotide similarity to regions of P. gingivalis genomes including ISs were predominant. The proportion of such spacers to all the unique spacers (1.6%: 19/1,187) was the highest among previous studies, suggesting novel functions for these CRISPRs. These results indicate that P. gingivalis is a bacterium with high intraspecies diversity caused by frequent insertion sequence (IS) transposition, whereas both the introduction of foreign DNA, primarily from other P. gingivalis cells, and IS transposition are limited by CRISPR interference. It is suggested that P. gingivalis CRISPRs could be an important source for understanding the role of CRISPRs in the development of bacterial diversity.
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Sawabe T, Ogura Y, Matsumura Y, Feng G, Amin AR, Mino S, Nakagawa S, Sawabe T, Kumar R, Fukui Y, Satomi M, Matsushima R, Thompson FL, Gomez-Gil B, Christen R, Maruyama F, Kurokawa K, Hayashi T. Updating the Vibrio clades defined by multilocus sequence phylogeny: proposal of eight new clades, and the description of Vibrio tritonius sp. nov. Front Microbiol 2013; 4:414. [PMID: 24409173 PMCID: PMC3873509 DOI: 10.3389/fmicb.2013.00414] [Citation(s) in RCA: 183] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 12/16/2013] [Indexed: 12/13/2022] Open
Abstract
To date 142 species have been described in the Vibrionaceae family of bacteria, classified into seven genera; Aliivibrio, Echinimonas, Enterovibrio, Grimontia, Photobacterium, Salinivibrio and Vibrio. As vibrios are widespread in marine environments and show versatile metabolisms and ecologies, these bacteria are recognized as one of the most diverse and important marine heterotrophic bacterial groups for elucidating the correlation between genome evolution and ecological adaptation. However, on the basis of 16S rRNA gene phylogeny, we could not find any robust monophyletic lineages in any of the known genera. We needed further attempts to reconstruct their evolutionary history based on multilocus sequence analysis (MLSA) and/or genome wide taxonomy of all the recognized species groups. In our previous report in 2007, we conducted the first broad multilocus sequence analysis (MLSA) to infer the evolutionary history of vibrios using nine housekeeping genes (the 16S rRNA gene, gapA, gyrB, ftsZ, mreB, pyrH, recA, rpoA, and topA), and we proposed 14 distinct clades in 58 species of Vibrionaceae. Due to the difficulty of designing universal primers that can amplify the genes for MLSA in every Vibrionaceae species, some clades had yet to be defined. In this study, we present a better picture of an updated molecular phylogeny for 86 described vibrio species and 10 genome sequenced Vibrionaceae strains, using 8 housekeeping gene sequences. This new study places special emphasis on (1) eight newly identified clades (Damselae, Mediterranei, Pectenicida, Phosphoreum, Profundum, Porteresiae, Rosenbergii, and Rumoiensis); (2) clades amended since the 2007 proposal with recently described new species; (3) orphan clades of genomospecies F6 and F10; (4) phylogenetic positions defined in 3 genome-sequenced strains (N418, EX25, and EJY3); and (5) description of V. tritonius sp. nov., which is a member of the “Porteresiae” clade.
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Mori H, Maruyama F, Kato H, Toyoda A, Dozono A, Ohtsubo Y, Nagata Y, Fujiyama A, Tsuda M, Kurokawa K. Design and experimental application of a novel non-degenerate universal primer set that amplifies prokaryotic 16S rRNA genes with a low possibility to amplify eukaryotic rRNA genes. DNA Res 2013; 21:217-27. [PMID: 24277737 PMCID: PMC3989492 DOI: 10.1093/dnares/dst052] [Citation(s) in RCA: 273] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The deep sequencing of 16S rRNA genes amplified by universal primers has revolutionized our understanding of microbial communities by allowing the characterization of the diversity of the uncultured majority. However, some universal primers also amplify eukaryotic rRNA genes, leading to a decrease in the efficiency of sequencing of prokaryotic 16S rRNA genes with possible mischaracterization of the diversity in the microbial community. In this study, we compared 16S rRNA gene sequences from genome-sequenced strains and identified candidates for non-degenerate universal primers that could be used for the amplification of prokaryotic 16S rRNA genes. The 50 identified candidates were investigated to calculate their coverage for prokaryotic and eukaryotic rRNA genes, including those from uncultured taxa and eukaryotic organelles, and a novel universal primer set, 342F-806R, covering many prokaryotic, but not eukaryotic, rRNA genes was identified. This primer set was validated by the amplification of 16S rRNA genes from a soil metagenomic sample and subsequent pyrosequencing using the Roche 454 platform. The same sample was also used for pyrosequencing of the amplicons by employing a commonly used primer set, 338F-533R, and for shotgun metagenomic sequencing using the Illumina platform. Our comparison of the taxonomic compositions inferred by the three sequencing experiments indicated that the non-degenerate 342F-806R primer set can characterize the taxonomic composition of the microbial community without substantial bias, and is highly expected to be applicable to the analysis of a wide variety of microbial communities.
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