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  • 1
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 134 (1995), S. 0 
    ISSN: 1574-6968
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Abstract The phylogeny of a symbiotic methanogen inhabiting the gut of a lower termite, Reticulitermes speratus, was analysed without cultivation. The small subunit ribosomal RNA gene (ssrDNA) and a 640-bp portion of the gene encoding subunit A of methyl coenzyme M reductase (mcrA) were amplified from a mixed-population DNA of the termite gut by polymerase chain reaction and cloned. The nucleotide sequence of the ssrDNA and the predicted amino acid sequence of the mcrA product were compared with those of the known methanogens. Both comparisons indicated that the termite symbiotic methanogen belonged to the order Methanobacteriales but was distinct from the known members of this order.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    ISSN: 1399-0047
    Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Thema: Chemie und Pharmazie , Geologie und Paläontologie , Physik
    Notizen: Meso-2,3-butanediol dehydrogenase (meso-BDH) has been crystallized and preliminary X-ray crystallographic characterization of meso-BDH crystals has been performed. Single crystals of meso-BDH were prepared in two forms by the hanging-drop vapour-diffusion method using polyethylene glycol as a precipitant. Form I crystals belong to space group C2, with unit-cell parameters a = 215.5, b = 79.4, c = 134.8 Å, β = 98.22°, and form II crystals belong to space group P21, with unit-cell parameters a = 69.16, b = 109.78, c = 127.28 Å, β = 102.29°. The crystals diffracted to 2.0 and 1.7 Å resolutions, respectively, using synchrotron radiation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology ecology 45 (2003), S. 0 
    ISSN: 1574-6941
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 221 (2003), S. 0 
    ISSN: 1574-6968
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: We investigated biases occurring in the polymerase chain reaction (PCR) amplification of 16S rRNA genes from an environmental sample, by comparing the clone libraries that we had previously prepared from the gut homogenate of the termite Reticulitermes speratus. We detected a significant increase in the expected number of phylotypes by lowering the annealing temperature, and a significant decrease in the proportion of clones belonging to the predominant group by raising the number of PCR cycles. We also found that the Bacteria-universal primer, 63F, introduced a seriously biased amplification caused by primer mismatches, in contrast to a previous report. These results, together with suggestions from previous studies using simplified model samples, will help us to recognize the limitations of PCR-based analysis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    ISSN: 1574-6941
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: The bacterial community colonizing the gut wall of the termite Reticulitermes speratus was characterized without cultivation. Analysis of 16S rRNA genes after fractionation of the gut revealed that the bacterial composition on the gut wall was diverse and significantly different from that able to move unconfined in the gut fluid or physically associated with the gut protists. Actinobacteria, Firmicutes and Bacteroidetes were dominant on the gut wall, but Spirochaetes and the Termite group 1 phylum, abundant in the gut lumen, were relatively rare. A sequence-specific probe enabled the in situ detection of a rod-shaped Actinobacteria member, abundantly colonizing the gut paunch epithelium.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 171 (1999), S. 0 
    ISSN: 1574-6968
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Termites harbor symbiotic microorganisms in their gut which emit methane. The phylogeny of the termite methanogens was inferred without cultivation based on nucleotide sequences of PCR-amplified 16S ribosomal RNA genes. Seven methanogen sequences from four termite species were newly isolated, and together with those previously published, these sequences were phylogenetically compared. The termite methanogen sequences were divided into three clusters. Two clusters of sequences, derived from the gut DNA of so-called higher termites, were related to methanogens in the orders Methanosarcinales or Methanomicrobiales. All of the sequences in the case of lower termites were closely related to the genus Methanobrevibacter. However, most of the termite symbionts were found to be distinct from known methanogens. They are not dispersed among diverse methanogen species, but rather formed unique lineages in the phylogenetic trees.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 164 (1998), S. 0 
    ISSN: 1574-6968
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: The phylogeny of microorganisms of the symbiotic community in the gut of a lower termite, Cryptotermes domesticus (order Isoptera, family Kalotermitidae), was investigated without culturing the resident microorganisms. Portions of the small-subunit rRNA genes (16S rRNAs) were directly amplified from the mixed-population DNA of the termite gut by the PCR and were clonally isolated. Analysis of partial sequences of 16S rRNA showed the existence of prokaryotic species related to the genera Methanobrevibacter, Leuconostoc, Bacteroides and Treponema, but most of the sequences were those of yet unknown species. Unique sequences showing very low sequence similarity to known 16S rRNA sequences were also found although they were significantly clustered with the High G+C Gram-positive bacteria. Comparisons of these sequences with those from the symbiotic microorganisms in other termite species revealed the existence of termite-specific groups of organisms.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 181 (1999), S. 0 
    ISSN: 1574-6968
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Phylogenetic relationships of symbiotic spirochetes in the gut of diverse termites were analyzed without cultivation of these microorganisms. A portion of the 16S rDNA (ca. 850 bp) was amplified directly from DNA of the mixed population in the gut by PCR and cloned. A total of 30 spirochetal phylotypes affiliated with the treponemes were identified from four termite species and they were compared with those already reported from other termites. They represented separate lines of descent from any known species of Treponema, and they were divided into two discrete clusters; one was related to Spirochaeta stenostrepta and S. caldaria, and the other was grouped together with members of the Treponema bryantii subgroup. Although some sequences from evolutionarily related termites showed close similarity, most of the sequences of spirochetes were dissimilar among different termite species, and spirochetal sequences from a single termite species occurred in several distinct phylogenetic positions. These findings suggest that termites constitute a rich reservoir of novel spirochetal diversity and that evolution of the symbiosis is not simple.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    ISSN: 1550-7408
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: The phylogeny of a symbiotic hypermastigote Trichonympha agilis (class Parabasalia; order Hypermastigida) in the hindgut of the lower termite Reticulitermes speratus was examined by a strategy that does not rely on cultivation. From mixed-population DNA obtained from the termite gut, small subunit (16S-like) ribosomal RNA sequences were directly amplified by the polymerase chain reaction method using primers specific for eukaryotes. Comparative sequence analysis of the clones revealed two kinds of sequences, one from the termite itself and the other from a symbiotic protist. A fluorescent-labeled oligonucleotide probe for the latter sequence was designed and used in whole-cell hybridization experiments to provide direct visual evidence that the sequence originated from a large hypermastigote in the termite hindgut, Trichonympha agilis. According to the phylogenetic trees constructed, the hypermastigote represented one of the deepest branches of eukaryotes. The hypermastigote along with members of the order Trichomonadida formed a monophyletic lineage, indicating that this hypermastigote and trichomonads shared a recent common ancestry.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 50 (2003), S. 0 
    ISSN: 1550-7408
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: . Oxymonads are a morphologically well-characterized and highly diverse lineage of protists. They are, however, under sampled at a molecular level. It has recently been demonstrated that a genus of oxymonads, Pyrsonympha, is phylogenetically related to the excavate taxon Trimastix. Here, we addressed issues of internal oxymonad evolution. Pyrsonympha and Dinenympha are shown, by fluorescent in situ hybridization and phylogenetic evidence, to be separate genera and not morphotypes of the same organism. We demonstrated that three genera of oxymonads, Dinenympha, Pyrsonympha, and Oxymonas are each monophyletic and together form a clade which excludes other known eukaryotes. We have presented a taxonomic scheme of oxymonads taking into account their sisterhood with Trimastix and speculated on morphological evolution of oxymonads, particularly of their attachment apparatuses. Our biogeographical analysis with Japanese and Canadian Pyrsonympha and Dinenympha suggests that these genera diverged before the separation of termites that inhabit Eastern Asia and Western North America.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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