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    Jared Leadbetter

    Microorganisms have evolved a spectacular diversity of metabolisms, some of which allow them to overcome environmental constraints, utilize abundant but inaccessible resources and drive nutrient cycling in various ecosystems. The termite... more
    Microorganisms have evolved a spectacular diversity of metabolisms, some of which allow them to overcome environmental constraints, utilize abundant but inaccessible resources and drive nutrient cycling in various ecosystems. The termite hindgut microbial community is optimized to metabolize wood, and in recent years, the in situ physiological and ecological functions of community members have been researched. Spirochetes are abundant in the termite gut, and herein, putative aromatic meta-cleavage pathway genes typical of aerobic pseudomonads were located in genomes of homoacetogenic termite hindgut 'anaerobes', Treponema primitia str. ZAS-1 and ZAS-2. Phylogenetic analyses suggest the T. primitia catechol 2,3-dioxygenase and several other essential meta-pathway genes were acquired from an α-proteobacterium in the distant past to augment several genes T. primitia acquired from anaerobic firmicutes that do not directly catabolize aromatics but can contribute to the final pathway steps. Further, transcripts for each meta-pathway gene were expressed in strictly anaerobic cultures of T. primitia str. ZAS-2 indicative of constitutive pathway expression. Also, the addition of catechol + O(2) to T. primitia liquid cultures resulted in the transient accumulation of trace amounts of the yellow ring cleavage product, hydroxymuconic semialdehyde. This is the first evidence of aromatic ring cleavage in the phylum (division) Spirochetes. Results also support a possible role for T. primitia in termite hindgut O(2) /lignin aromatic monomer metabolism. Potential O(2) -dependent yet nonrespiratory microbial metabolisms have heretofore been overlooked and warrant further investigation. These metabolisms could describe the degradation of plant-derived and other aromatics in microoxic environments and contribute significantly to carbon turnover.
    Many bacteria communicate by using dedicated signalling molecules. Signal-degrading enzymes from other bacteria interrupt the conversation, and can protect tobacco and potato plants from infection.
    The structure of the signaling molecule of Vibrio fischeri, N-3-(oxohexanoyl) homoserine lactone (3OC6HSL), was determined and was the first representative of a large family of molecules, the acylhomoserine lactones (acyl-HSLs). For... more
    The structure of the signaling molecule of Vibrio fischeri, N-3-(oxohexanoyl) homoserine lactone (3OC6HSL), was determined and was the first representative of a large family of molecules, the acylhomoserine lactones (acyl-HSLs). For microbes that degrade acyl-HSL signals but are not responsible for accumulation of acyl-HSLs or have quorum-sensing systems, acyl-HSL degradation could provide a means to compete with acyl-HSL-producing, quorum-sensing neighbors in the environment. Acyl-HSL quorum signal degradation is important if the presence and concentration of these signaling molecules are important for several microbial group behaviors. Acyl-HSL-degrading microbes that use acyl-HSLs as either a sole carbon source or carbon and nitrogen source could gain an additional advantage in soil environments where nutrients are limited. The possibility that acyl-HSL-mediated quorum sensing is widespread suggests that it may be seeing tip of the iceberg in terms of microbes and organisms with acyl-HSL-degrading potential.
    ... This was first documented over a century ago by Joseph Leidy (Leidy, 1874–1881; Leidy, 1877), who was struck by their abundance in hindgut contents of the eastern subterranean ter-mite, Termes (now Reticulitermes) flavipes. ...
    ... 발행기관, 대한환경공학회. - 발행정보, 춘계 공동학술대회 , 2007 권 , 단일호 , Startpage 32 , Endpage 32 , Totalpage 1. - 저자, ( Jennifer O`Neil ) , ( Jean J. Huang ) , ( Jared R. Leadbetter ) , ( Jong In Han ). - 가격, 1,000 원. - 발행년도, 2007. - 주제키워드, 입력된 주제키워드가... more
    ... 발행기관, 대한환경공학회. - 발행정보, 춘계 공동학술대회 , 2007 권 , 단일호 , Startpage 32 , Endpage 32 , Totalpage 1. - 저자, ( Jennifer O`Neil ) , ( Jean J. Huang ) , ( Jared R. Leadbetter ) , ( Jong In Han ). - 가격, 1,000 원. - 발행년도, 2007. - 주제키워드, 입력된 주제키워드가 없습니다 ...
    Manganese (Mn) is an abundant redox-active metal that cycles in many of Earth’s biomes. While diverse bacteria and archaea have been demonstrated to respire Mn(III/IV), only recently have bacteria been implicated in Mn(II)... more
    Manganese (Mn) is an abundant redox-active metal that cycles in many of Earth’s biomes. While diverse bacteria and archaea have been demonstrated to respire Mn(III/IV), only recently have bacteria been implicated in Mn(II) oxidation-dependent growth.
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    When prokaryotic cells acquire mutations, encounter translation-inhibiting substances, or experience adverse environmental conditions that limit their ability to synthesize proteins, transcription can become uncoupled from translation.... more
    When prokaryotic cells acquire mutations, encounter translation-inhibiting substances, or experience adverse environmental conditions that limit their ability to synthesize proteins, transcription can become uncoupled from translation. Such uncoupling is known to suppress transcription of protein-encoding genes in bacteria. Here we show that the trace element selenium controls transcription of the gene for the selenocysteine-utilizing enzyme formate dehydrogenase (fdhFSec) through a translation-coupled mechanism in the termite gut symbiont Treponema primitia, a member of the bacterial phylum Spirochaetes. We also evaluated changes in genome-wide transcriptional patterns caused by selenium limitation and by generally uncoupling translation from transcription via antibiotic-mediated inhibition of protein synthesis. We observed that inhibiting protein synthesis in T. primitia influences transcriptional patterns in unexpected ways. In addition to suppressing transcription of certain genes, the expected consequence of inhibiting protein synthesis, we found numerous examples in which transcription of genes and operons is truncated far downstream from putative promoters, is unchanged, or is even stimulated overall. These results indicate that gene regulation in bacteria allows for specific post-initiation transcriptional responses during periods of limited protein synthesis, which may depend both on translational coupling and on unclassified intrinsic elements of protein-encoding genes
    acetaldehyde dehydrogenase original MUSCLE alignment.tx
    catechol 2,3-dioxygenase Mr Bayes output.nex.con.tr
    acetaldehyde dehydrogenase ARB output.ne

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