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Catabolic - Astrophysics Data System

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Last Updated: 10 May 2022

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Both catabolic and anabolic heterotrophic microbial activity proceed in frozen soils

A significant amount of the global soil carbon pool is held in soils of high-latitude ecosystems, where microbial processes and production of greenhouse gases occur during the winter months. Both catabolic and anabolic processes persist under frozen conditions, and no significant differences in carbon exchange between [ 13 C]glucose and cell organic 13 C-compounds occurred between +9 °C and (4) °C, according to our reports, which show that the soil microorganisms maintain both catabolic and anabolic processes under freezing conditions. The finding that the freezing soil processes are similar to those in unfrozen soil has important implications for our general understanding and conceptualization of soil carbon dynamics in high-latitude ecosystems.

Source link: https://ui.adsabs.harvard.edu/abs/2010PNAS..10721046D/abstract


Host Range of the Conjugative Transfer System of IncP-9 Naphthalene-Catabolic Plasmid NAH7 and Characterization of Its oriT Region and Relaxase

We examined the NAH7-encoded conjugation scheme in this report by determining the earliest traces of its conjugation coding system and its relaxationase, specifically nicks within the oriT region for initiation of transfer, as well as comparing the conjugation schemes between NAH7 and pWW0. The NAH7 oriT region was located within a 430-bp piece, and the strand-specific nicking site and its upstream sequences that were crucial for effective conjugation in the oriT N zone were identified. Unlike other relaxers, the NAH7 relaxase contained unique characteristics in its ability to catalyze, in a conjugation-independence manner, between two versions of the oriT N region, both copies of the pWW0 oriT zone, and between the oriT N and oriT W regions. In the presence of the NAH7 nic derivative, conjugatively transferable to alphaproteobacterial and betaproteobacterial strains in which the NAH7 replication machinery is nonfunctional, the plasmid was shedding, meaning that the NAH7 conjugation device has a broader host range than its replication machine. IMPORTANCE IMPACTANCE IMPORTANCE NOTES IMPORTANCE IMPACTANCE IMPORTANCE IMPACTANCE IMPORTANCE IMPORT IMPORTABILITY IMPORTANCE The NAH7 oriT relaxase unit has important characteristics that are significantly different from other well-studied techniques, and the host range of the NAH7 conjugation system is wider than previously expected, according to this research.

Source link: https://ui.adsabs.harvard.edu/abs/2017ApEnM..83E2359K/abstract


Conjugative Transfer of IncP-9 Catabolic Plasmids Requires a Previously Uncharacterized Gene, mpfK , Whose Homologs Are Conserved in Various MPF T -Type Plasmids

IncP-9 plasmids are important mobile genetic components for the degradation of various aromatic hydrocarbons. Our analysis revealed that the NAH7 conjugation system specifically requires, in comparison to the conserved components of the type IV secretion device, a newly isolated periplasmic protein, MpfK, for successful conjugation. ABSTRACT CONJURIT BACKGROUND Transfer of bacterial plasmids to recipient cells is often facilitated by type IV secretion machinery. According to plasmids, experimental studies into the minimal gene sets required for efficient conjugative transfer show that such gene sets are variable, depending on plasmids. MpfK was localized in periplasm and had four cysteine residues whose intramolecular or intermolecular disulfide bond formation was found to be critical for efficient conjugation transfer. Several MPF T plasmids, including non-IncP-9 plasmids, were specifically distributed in mpfK homologs, including non-IncP-9 plasmids like R388 and R751. The mpfK homologs from the two non-IncP-9 plasmids were not intended for conjugation of their plasmids, but they were able to resolve quickly the transfer defect of the NAH7 mpfK mutant. Our findings revealed the importance of mpfK homologs for conjugative transfer of MPF T plasmids of type T plasmids. IMPORTANCE IncP-9 plasmids are essential cell genetic components for the degradation of various aromatic hydrocarbons. According to our review, the NAH7 conjugation scheme specifically needs, in addition to the conserved components of the type IV secretion device, a previously unknown periplasmic protein, MpfK, for successful conjugation.

Source link: https://ui.adsabs.harvard.edu/abs/2019ApEnM..85E1850K/abstract


Isolation of the (+)-Pinoresinol-Mineralizing Pseudomonas sp. Strain SG-MS2 and Elucidation of Its Catabolic Pathway

ABSTRACT Pinoresinol is a dimer of two -linked coniferyl alcohol molecules. ' Both a plant defense molecule synthesized via the shikimic acid pathway and a representative of many -linked dimers made during the microbial degradation of lignin in dead plant tissue are mixed. Pinoresinol degradation in strain SG-MS2 is triggered by phenolylic hydroxylation, cell suspension, and resting cell experiments, resulting in a hemiketal with a quinone methide intermediate that is then hydrated at the benzylic carbon by water, based on enzyme assays and bacterial growth. IMPORTANCE The oxidative catabolism of -pinoresinol degradation elucidated here is qualitatively different from the reductive cometabolism described for two previously described bacteria. Our findings also have ramifications for the discovery of new pinoresinol metabolites in human health. The enterodiol and enterolactone produced by reductive conversion of pinoresinol by gut microbes have already been linked to reduced risks of cardiovascular and cardiovascular disease.

Source link: https://ui.adsabs.harvard.edu/abs/2018ApEnM..84E2531S/abstract


Functional Characterization of a 28-Kilobase Catabolic Island from Pseudomonas sp. Strain M1 Involved in Biotransformation of β-Myrcene and Related Plant-Derived Volatiles

ABSTRACT Pseudomonas sp. Pseudomonas sp. The ability to use such a variety of chemicals as the sole carbon source is, most likely, related to a genetic background that has evolved under diverse environmental constraints. The outstanding results of strain M1 related to -myrcene catabolism were elucidated in this study, with a focus on the -myrcene-associated core code, which was embedded in a 28-kb genomic island, and destined to be divided into 8 transcriptional units. The genetic organisation predicted in silico and traced the -myrcene-induced promoter activity to the manufacture of -myrcene derivatives, according to a functional analysis of the morphology of this locus with promoter probes and analytical techniques. Notably, new genotypes of the 28-kb GI were created by a whole-genome mutagenesis scheme, leading to the discovery of a novel putative hydroxylase, which is responsible for the initial oxidation of -myrcene into myrcen-8-ol, and a sensor-like regulatory protein, whose inactivation abolished the myr+ characteristic of M1 cells. In addition, it was found that the M1 enzymatic repertoire's range of monoterpene substrates, in addition to'myrcene, includes other acyclic and cyclic [e. g. , R—limonene and -pinene] molecules. Our findings are the stepping stone for following metabolic engineering techniques and hint at a pivotal role of the 28-kb GI in the biosynthesis of a broad monoterpene backbone array for its future biotechnological applications. This research contributes to the development of a new molecular functionalities of plant-derived volatile catabolic pathways by providing new insight into the intricate molecular mechanisms of '-myrcene catabolism in Pseudomonas, enforcing the production of a molecular evidence base that provides new insight into the plant-derived volatile catabolic pathways.

Source link: https://ui.adsabs.harvard.edu/abs/2017ApEnM..83E3112S/abstract


Bacterial phenylalanine and phenylacetate catabolic pathway revealed

Aromatic compounds form the second most prevalent class of organic substrates and environmental pollutants, with a significant portion of which is metabolized by bacteria by phenylacetate. Surprisingly, the bacterial degradation of phenylalanine and phenylacetate remained unsolved issue. Although a phenylacetate metabolic gene cluster had been identified, the actual biochemistry remained largely unknown. Here we explain the catabolic pathway responsible for 16% of all bacteria sequenced, including Escherichia coli and Pseudomonas putida. Intermediates are processed as CoA thioesters, and the phenolic ring of phenylacetyl-CoA becomes activated to a ring 1,2-epoxide by a distinct multicomponent oxygenase.

Source link: https://ui.adsabs.harvard.edu/abs/2010PNAS..10714390T/abstract

* Please keep in mind that all text is summarized by machine, we do not bear any responsibility, and you should always check original source before taking any actions

* Please keep in mind that all text is summarized by machine, we do not bear any responsibility, and you should always check original source before taking any actions