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Find video protocols related to scientific articles indexed in Pubmed.
Draft Genome Sequences of Vibrio sp. Strains Isolated from Tetrodotoxin-Bearing Scavenging Gastropod.
Genome Announc
PUBLISHED: 06-21-2014
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Vibrio sp. strains JCM 18905 and JCM 19053 were isolated from a tetrodotoxin (TTX)-bearing scavenging gastropod, and Vibrio sp. strain JCM 18904 was isolated from a sea cucumber. All these are closely related to Vibrio alginolyticus. Their comparative genome information is useful for studies of TTX production in bacteria.
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Draft Genome Sequences of Geomicrobium sp. Strains JCM 19037, JCM 19038, JCM 19039, and JCM 19055, Isolated from Aquatic Samples.
Genome Announc
PUBLISHED: 06-21-2014
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Haloalkaliphilic strains JCM 19037, JCM 19038, JCM 19039, and JCM 19055, closely related to Geomicrobium sediminis, were isolated from aquatic samples, and their draft genome sequences were determined. The genome information of these four strains will be useful for studies of their physiology and ecology.
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The nitrogen cycle in cryoconites: naturally occurring nitrification-denitrification granules on a glacier.
Environ. Microbiol.
PUBLISHED: 06-13-2014
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Cryoconites are microbial aggregates commonly found on glacier surfaces where they tend to take spherical, granular forms. While it has been postulated that the microbes in cryoconite granules play an important role in glacier ecosystems, information on their community structure is still limited, and their functions remain unclear. Here, we present evidence for the occurrence of nitrogen cycling in cryoconite granules on a glacier in Central Asia. We detected marker genes for nitrogen fixation, nitrification and denitrification in cryoconite granules by digital polymerase chain reaction (PCR), while digital reverse transcription PCR analysis revealed that only marker genes for nitrification and denitrification were abundantly transcribed. Analysis of isotope ratios also indicated the occurrence of nitrification; nitrate in the meltwater on the glacier surface was of biological origin, while nitrate in the snow was of atmospheric origin. The predominant nitrifiers on this glacier belonged to the order Nitrosomonadales, as suggested by amoA sequences and 16S ribosomal RNA pyrosequencing analysis. Our results suggest that the intense carbon and nitrogen cycles by nitrifiers, denitrifiers and cyanobacteria support abundant and active microbes on the Asian glacier.
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Draft Genome Sequences of Psychrobacter Strains JCM 18900, JCM 18901, JCM 18902, and JCM 18903, Isolated Preferentially from Frozen Aquatic Organisms.
Genome Announc
PUBLISHED: 04-05-2014
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Four Psychrobacter strains, JCM 18900, JCM 18901, JCM 18902, and JCM 18903, related to either Psychrobacter nivimaris or Psychrobacter cibarius, were isolated from frozen marine animals. The genome information of these four strains will be useful for studies of their physiology and adaptation properties to frozen conditions.
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Draft Genome Sequences of Cyclodextrin-Producing Alkaliphilic Bacillus Strains JCM 19045, JCM 19046, and JCM 19047.
Genome Announc
PUBLISHED: 03-22-2014
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Bacillus strains JCM 19045, JCM 19046, and JCM 19047 are alkaliphiles that produce ?-cyclodextrin from starch. They are related to Bacillus xiaoxiensis and Bacillus lehensis. The genome information for these three strains will be useful for studies of the physiological role of cyclodextrin and cyclodextrin production.
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Comprehensive Phylogenetic Diversity of [FeFe]-Hydrogenase Genes in Termite Gut Microbiota.
Microbes Environ.
PUBLISHED: 11-15-2013
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Phylogenetic diversity of [FeFe]-hydrogenase (HydA) in termite guts was assessed by pyrosequencing PCR amplicons obtained using newly designed primers. Of 8,066 reads, 776 hydA phylotypes, defined with 97% nucleotide sequence identity, were recovered from the gut homogenates of three termite species, Hodotermopsis sjoestedti, Reticulitermes speratus, and Nasutitermes takasagoensis. The phylotype coverage was 92-98%, and the majority shared only low identity with database sequences. It was estimated that 194-745 hydA phylotypes existed in the gut of each termite species. Our results demonstrate that hydA gene diversity in the termite gut microbiota is much higher than previously estimated.
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Intranuclear verrucomicrobial symbionts and evidence of lateral gene transfer to the host protist in the termite gut.
ISME J
PUBLISHED: 07-11-2013
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In 1944, Harold Kirby described microorganisms living within nuclei of the protists Trichonympha in guts of termites; however, their taxonomic assignment remains to be accomplished. Here, we identified intranuclear symbionts of Trichonympha agilis in the gut of the termite Reticulitermes speratus. We isolated single nuclei of T. agilis, performed whole-genome amplification, and obtained bacterial 16S rRNA genes by PCR. Unexpectedly, however, all of the analyzed clones were from pseudogenes of 16S rRNA with large deletions and numerous sequence variations even within a single-nucleus sample. Authentic 16S rRNA gene sequences were finally recovered by digesting the nuclear DNA; these pseudogenes were present on the host Trichonympha genome. The authentic sequences represented two distinct bacterial species belonging to the phylum Verrucomicrobia, and the pseudogenes have originated from each of the two species. Fluorescence in situ hybridization confirmed that both species are specifically localized, and occasionally co-localized, within nuclei of T. agilis. Transmission electron microscopy revealed that they are distorted cocci with characteristic electron-dense and lucent regions, which resemble the intranuclear symbionts illustrated by Kirby. For these symbionts, we propose a novel genus and species, Candidatus Nucleococcus trichonymphae and Candidatus Nucleococcus kirbyi. These formed a termite-specific cluster with database sequences, other members of which were also detected within nuclei of various gut protists, including both parabasalids and oxymonads. We suggest that this group is widely distributed as intranuclear symbionts of diverse protists in termite guts and that they might have affected the evolution of the host genome through lateral gene transfer.
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Defensive bacteriome symbiont with a drastically reduced genome.
Curr. Biol.
PUBLISHED: 04-12-2013
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Diverse insect species harbor symbiotic bacteria, which play important roles such as provisioning nutrients and providing defense against natural enemies [1-6]. Whereas nutritional symbioses are often indispensable for both partners, defensive symbioses tend to be of a facultative nature [1-12]. The Asian citrus psyllid Diaphorina citri is a notorious agricultural pest that transmits Liberibacter spp. (Alphaproteobacteria), causing the devastating citrus greening disease or Huanglongbing [13, 14]. In a symbiotic organ called the bacteriome, D. citri harbors two distinct intracellular symbionts: a putative nutrition provider, Carsonella_DC (Gammaproteobacteria), and an unnamed betaproteobacterium with unknown function [15], for which we propose the name "Candidatus Profftella armatura." Here we report that Profftella is a defensive symbiont presumably of an obligate nature with an extremely streamlined genome. The genomes of Profftella and Carsonella_DC were drastically reduced to 464,857 bp and 174,014 bp, respectively, suggesting their ancient and mutually indispensible association with the host. Strikingly, 15% of the small Profftella genome encoded horizontally acquired genes for synthesizing a novel polyketide toxin. The toxin was extracted, pharmacologically and structurally characterized, and designated diaphorin. The presence of Profftella and its diaphorin-biosynthetic genes was perfectly conserved in the worlds D. citri populations.
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Native architecture of the centriole proximal region reveals features underlying its 9-fold radial symmetry.
Curr. Biol.
PUBLISHED: 03-20-2013
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Centrioles are cylindrical microtubule-based structures whose assembly is critical for the formation of cilia, flagella, and centrosomes. The centriole proximal region harbors a cartwheel that dictates the 9-fold symmetry of centrioles. Although the cartwheel architecture has been recently analyzed, how it connects to the peripheral microtubules is not understood. More generally, a high-resolution view of the proximal region of the centriole is lacking, thus limiting understanding of the underlying assembly mechanisms.
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Molecular diversity of endosymbiotic Nephroselmis (Nephroselmidophyceae) in Hatena arenicola (Katablepharidophycota).
J. Plant Res.
PUBLISHED: 02-03-2013
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Hatena arenicola (Katablepharidophycota) is a single-celled eukaryote that temporarily possesses a chlorophyte alga of the genus Nephroselmis as an intracellular symbiont. In the present study, we investigated the molecular diversity of the endosymbiont Nephroselmis in a natural population of the host H. arenicola. We sequenced the hosts 18S rRNA gene and the endosymbionts plastid-encoded 16S rRNA gene. The results indicated that almost identical strains of the host harbored at least three distinct strains of the algal endosymbiont affiliated to the clade Nephroselmis rotunda. This finding supports our previous hypothesis that H. arenicola and its symbiotic alga are in an early stage of secondary endosymbiosis.
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Horizontal gene acquisition of liberibacter plant pathogens from a bacteriome-confined endosymbiont of their psyllid vector.
PLoS ONE
PUBLISHED: 01-01-2013
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he Asian citrus psyllid Diaphorina citri is a notorious agricultural pest that transmits the phloem-inhabiting alphaproteobacterial Candidatus Liberibacter asiaticus and allied plant pathogens, which cause the devastating citrus disease called Huanglongbing or greening disease. D. citri harbors two distinct bacterial mutualists in the symbiotic organ called bacteriome: the betaproteobacterium Candidatus Profftella armatura in the syncytial cytoplasm at the center of the bacteriome, and the gammaproteobacterium Candidatus Carsonella ruddii in uninucleate bacteriocytes. Here we report that a putative amino acid transporter LysE of Profftella forms a highly supported clade with proteins of L. asiaticus, L. americanus, and L. solanacearum. L. crescens, the most basal Liberibacter lineage currently known, lacked the corresponding gene. The Profftella-Liberibacter subclade of LysE formed a clade with proteins from betaproteobacteria of the order Burkholderiales, to which Profftella belongs. This phylogenetic pattern favors the hypothesis that the Liberibacter lineage acquired the gene from the Profftella lineage via horizontal gene transfer (HGT) after L. crescens diverged from other Liberibacter lineages. K A/K S analyses further supported the hypothesis that the genes encoded in the Liberibacter genomes are functional. These findings highlight the possible evolutionary importance of HGT between plant pathogens and their insect vectors symbionts that are confined in the symbiotic organ and seemingly sequestered from external microbial populations.
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Whole-genome sequencing of unculturable bacterium using whole-genome amplification.
Methods Mol. Biol.
PUBLISHED: 03-25-2011
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More than 99% of microorganisms on the earth are unculturable with known culturing techniques. The emergence of metagenomics with high-throughput sequencing technologies has enabled researchers to capture a comprehensive view of a complex bacterial community which comprises both culturable and unculturable species. However, the function of an individual species remains difficult to elucidate in a conventional metagenomic study, which generates numerous genomic fragments of unidentifiable origins at a species or genus level. This limitation hampers any in-depth investigations of the community and its unculturable bacterial members. Recently, as an alternative or compensatory approach, genomics targeting a single unculturable bacterial species in a complex community has been proposed. In this approach, whole-genome amplification technique using Phi29 DNA polymerase is applied to obtain a sufficient quantity of DNA for genome sequence analysis from only a single to a thousand bacterial cells. It is expected that a combination of the conventional metagenomics and this single-species-targeting genomics provides a great progress in understanding of the ecology, physiology, and evolution of unculturable microbial communities.
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Toward the functional analysis of uncultivable, symbiotic microorganisms in the termite gut.
Cell. Mol. Life Sci.
PUBLISHED: 02-10-2011
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Termites thrive on dead plant matters with the aid of microorganisms resident in their gut. The gut microbiota comprises protists (single-celled eukaryotes), bacteria, and archaea, most of which are unique to the termite gut ecosystem. Although this symbiosis has long been intriguing researchers of both basic and applied sciences, its detailed mechanism remains unclear due to the enormous complexity and the unculturability of the microbiota. In the effort to overcome the difficulty, recent advances in omics, such as metagenomics, metatranscriptomics, and metaproteomics have gradually unveiled the black box of this symbiotic system. Genomics targeting a single species of the unculturable microbial members has also provided a great progress in the understanding of the symbiotic interrelationships among the gut microorganisms. In this review, the symbiotic system organized by wood-feeding termites and their gut microorganisms is outlined, focusing on the recent achievement in omics studies of this multilayered symbiotic system.
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Diversity and genomes of uncultured microbial symbionts in the termite gut.
Biosci. Biotechnol. Biochem.
PUBLISHED: 06-07-2010
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Termites play a key role in the global carbon cycle as decomposers. Their ability to thrive solely on dead plant matter is chiefly attributable to the activities of gut microbes, which comprise protists, bacteria, and archaea. Although the majority of the gut microbes are as yet unculturable, molecular analyses have gradually been revealing their diversity and symbiotic mechanisms. Culture-independent studies indicate that a single termite species harbors several hundred species of gut microbes unique to termites, and that the microbiota is consistent within a host termite species. To elucidate the functions of these unculturable symbionts, environmental genomics has recently been applied. Particularly, single-species-targeting metagenomics has provided a breakthrough in the understanding of symbiotic roles, such as the nitrogen fixation, of uncultured, individual microbial species. A combination of single-species-targeting metagenomics, conventional metagenomics, and metatranscriptomics should be a powerful tool to dissect this complex, multi-layered symbiotic system.
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Complex coevolutionary history of symbiotic Bacteroidales bacteria of various protists in the gut of termites.
BMC Evol. Biol.
PUBLISHED: 07-09-2009
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The microbial community in the gut of termites is responsible for the efficient decomposition of recalcitrant lignocellulose. Prominent features of this community are its complexity and the associations of prokaryotes with the cells of cellulolytic flagellated protists. Bacteria in the order Bacteroidales are involved in associations with a wide variety of gut protist species as either intracellular endosymbionts or surface-attached ectosymbionts. In particular, ectosymbionts exhibit distinct morphological patterns of the associations. Therefore, these Bacteroidales symbionts provide an opportunity to investigate not only the coevolutionary relationships with the host protists and their morphological evolution but also how symbiotic associations between prokaryotes and eukaryotes occur and evolve within a complex symbiotic community.
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Inheritance and diversification of symbiotic trichonymphid flagellates from a common ancestor of termites and the cockroach Cryptocercus.
Proc. Biol. Sci.
PUBLISHED: 02-20-2009
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Cryptocercus cockroaches and lower termites harbour obligate, diverse and unique symbiotic cellulolytic flagellates in their hindgut that are considered critical in the development of social behaviour in their hosts. However, there has been controversy concerning the origin of these symbiotic flagellates. Here, molecular sequences encoding small subunit rRNA and glyceraldehyde-3-phosphate dehydrogenase were identified in the symbiotic flagellates of the order Trichonymphida (phylum Parabasalia) in the gut of Cryptocercus punctulatus and compared phylogenetically to the corresponding species in termites. In each of the monophyletic lineages that represent family-level groups in Trichonymphida, the symbionts of Cryptocercus were robustly sister to those of termites. Together with the recent evidence for the sister-group relationship of the host insects, this first comprehensive study comparing symbiont molecular phylogeny strongly suggests that a set of symbiotic flagellates representative of extant diversity was already established in an ancestor common to Cryptocercus and termites, was vertically transmitted to their offspring, and subsequently became diversified to distinct levels, depending on both the host and the symbiont lineages.
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Candidatus Desulfovibrio trichonymphae, a novel intracellular symbiont of the flagellate Trichonympha agilis in termite gut.
Environ. Microbiol.
PUBLISHED: 01-28-2009
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Rs-N31, a 16S rRNA phylotype affiliated with the genus Desulfovibrio, has frequently been detected from the gut of the wood-feeding termite Reticulitermes speratus. In this study, we designed a probe specifically targeting phylotype Rs-N31 and performed fluorescence in situ hybridization to identify the corresponding cells. The signals were detected exclusively inside the cells of the flagellate Trichonympha agilis, which simultaneously harbours another intracellular bacterium belonging to the candidate phylum Termite Group 1 (TG1). The detected cells were coccoid or short rods and specifically localized in the cortical layer of mainly, the anterior part of the flagellate cell. Approximately 1800 cells were contained in a single host cell, accounting for, in total, 2% of the whole prokaryotic gut microbiota. The genes dsrAB and apsA for sulfate reduction and a gene-encoding H(2)-uptake hydrogenase, both possessing a high sequence identity with those of known desulfovibrios, were obtained by polymerase chain reaction (PCR) from the host cells isolated using a micromanipulator, and their expression was verified by reverse-transcription PCR. Thus, we suggest that this endosymbiont acts as a sink for the hydrogen generated by both the flagellates and possibly TG1 symbionts. For this uncultured bacterium, we propose a novel species, Candidatus Desulfovibrio trichonymphae.
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Molecular identification of rickettsial endosymbionts in the non-phagotrophic volvocalean green algae.
PLoS ONE
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The order Rickettsiales comprises gram-negative obligate intracellular bacteria (also called rickettsias) that are mainly associated with arthropod hosts. This group is medically important because it contains human-pathogenic species that cause dangerous diseases. Until now, there has been no report of non-phagotrophic photosynthetic eukaryotes, such as green plants, harboring rickettsias.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.