Topic
Trichonympha
About: Trichonympha is a research topic. Over the lifetime, 48 publications have been published within this topic receiving 1867 citations.
Papers
TL;DR: The first complete genome sequence of a termite gut symbiont—an uncultured bacterium named Rs-D17 belonging to the candidate phylum Termite Group 1—is presented, suggesting that this bacterial group plays a key role in the gut symbiotic system by stably supplying essential nitrogenous compounds deficient in lignocelluloses to their host protists and the termites.
Abstract: Termites harbor a symbiotic gut microbial community that is responsible for their ability to thrive on recalcitrant plant matter. The community comprises diverse microorganisms, most of which are as yet uncultivable; the detailed symbiotic mechanism remains unclear. Here, we present the first complete genome sequence of a termite gut symbiont—an uncultured bacterium named Rs-D17 belonging to the candidate phylum Termite Group 1 (TG1). TG1 is a dominant group in termite guts, found as intracellular symbionts of various cellulolytic protists, without any physiological information. To acquire the complete genome sequence, we collected Rs-D17 cells from only a single host protist cell to minimize their genomic variation and performed isothermal whole-genome amplification. This strategy enabled us to reconstruct a circular chromosome (1,125,857 bp) encoding 761 putative protein-coding genes. The genome additionally contains 121 pseudogenes assigned to categories, such as cell wall biosynthesis, regulators, transporters, and defense mechanisms. Despite its apparent reductive evolution, the ability to synthesize 15 amino acids and various cofactors is retained, some of these genes having been duplicated. Considering that diverse termite-gut protists harbor TG1 bacteria, we suggest that this bacterial group plays a key role in the gut symbiotic system by stably supplying essential nitrogenous compounds deficient in lignocelluloses to their host protists and the termites. Our results provide a breakthrough to clarify the functions of and the interactions among the individual members of this multilayered symbiotic complex.
254 citations
TL;DR: By means of preliminary experiments, the osmotic pressure, pH, and mono- to bivalent ion ratio most favorable to the survival of the symbiotic intestinal flagellates of termites were determined and balanced salt solutions were constructed and tested, with the addition of cellulose and low concentrations of protein, as culture media.
Abstract: By means of preliminary experiments, the osmotic pressure, pH, and mono- to bivalent ion ratio most favorable to the survival of the symbiotic intestinal flagellates of termites were determined. On the basis of these and other facts, balanced salt solutions were constructed and tested, with the addition of cellulose and low concentrations of protein, as culture media.In this way a medium was obtained in which the xylophagous flagellate, Trichomonas termopsidis, from Termopsis angusticollis, has been cultured for over three years. A Trichomonas from Reticulitermes flavipes, and Tricercomitus termopsidis from Termopsis angusticollis were cultured in the same medium. The last two organisms did not require cellulose.In a somewhat different medium, excellent initial cultures of the hypermastigote, Trichonympha sphaerica, from Termopsis angusticollis, were obtained, and the organisms could be carried through a first subculture but not through a second. Attempts to improve the medium so as to secure continuous cu...
183 citations
TL;DR: Continuous axenic cultures were established of Trichonympha sphaerica, a cellulose-digesting symbiotic protozoon in the gut of a termite, and the cellulolytic activity of this flagellate is an inherent property and is not dependent on endosymbiotic bacteria.
Abstract: Continuous axenic cultures were established of Trichonympha sphaerica, a cellulose-digesting symbiotic protozoon in the gut of a termite. The cultured flagellates harbored no endosymbiotic bacteria and metabolized cellulose to acetate, carbon dioxide, and hydrogen. Thus, the cellulolytic activity of this flagellate is an inherent property and is not dependent on endosymbiotic bacteria.
120 citations
TL;DR: It is document that 'Endomicrobia' are present also in many other gut flagellates of lower termites and wood-feeding cockroaches, suggesting co-speciation between symbiont and host.
Abstract: ‘Endomicrobia’, a distinct and diverse group of uncultivated bacteria in the candidate phylum Termite Group I (TG-1), have been found exclusively in the gut of lower termites and wood-feeding cockroaches. In a previous study, we had demonstrated that the ‘Endomicrobia’ clones retrieved from Reticulitermes santonensis represent intracellular symbionts of the two major gut flagellates of this termite. Here, we document that ‘Endomicrobia’ are present also in many other gut flagellates of lower termites. Phylogeny and host specificity of ‘Endomicrobia’ were investigated by cloning and sequencing of the small subunit rRNA genes of the flagellate and the symbionts, which originated from suspensions of individual flagellates isolated by micropipette. Each flagellate harboured a distinct phylogenetic lineage of ‘Endomicrobia’. The results of fluorescent in situ hybridization with ‘Endomicrobia’-specific oligonucleotide probes corroborated that ‘Endomicrobia’ are intracellular symbionts specifically affiliated with their flagellate hosts. Interestingly, the ‘Endomicrobia’ sequences obtained from flagellates belonging to the genus Trichonympha formed a monophyletic group, suggesting co-speciation between symbiont and host.
85 citations
TL;DR: The phylogeny of all known parabasalian small subunit rRNAs was examined and found many taxonomic groups to be supported by rRNA, but not all.
Abstract: The phylogenetic diversity of parabasalian flagellates from termite hindguts has been examined by small subunit ribosomal RNA (rRNA) amplification and sequencing. Two species of particular interest, the giant trichomonad Pseudotrypanosoma giganteum and the hypermastigote Trichonympha magna, were isolated from the gut of Porotermes adamsoni by micropipetting, and the rRNA genes from these small populations amplified and sequenced, rRNA genes representing Hypermastigida and the Trichomonadida families Devescovinidae and Trichomonadidae, were also recovered by amplification from whole hindguts of three termites, P. adamsoni, Cryptotermes brevis, and Cryptotermes dudleyi. The parabasalian rRNA genes from C. brevis were found to comprise a unique and extremely heterogeneous lineage with no clear affinities to any known parabasalian rRNAs. In addition, one of the sequences isolated from P. adamsoni was found to he similar to another uncharacterised rRNA gene from Reticulitermes flavipes. The phylogeny of all known parabasalian small subunit rRNAs was examined with these new sequences. We find many taxonomic groups to be supported by rRNA, but not all. We have found the root of parabasalia to be very difficult to discern accurately, but have nevertheless identified several possible positions.
70 citations
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Performance Metrics
| Year | Papers |
|---|---|
| 2020 | 3 |
| 2019 | 1 |
| 2017 | 3 |
| 2016 | 3 |
| 2015 | 1 |
| 2014 | 1 |