Enrichment and isolation of a reductively debrominating bacterium from the burrow of a bromometabolite-producing marine hemichordate

1995 ◽  
Vol 41 (7) ◽  
pp. 637-642 ◽  
Author(s):  
Charles C. Steward ◽  
Terry C. Dixon ◽  
Yung Pin Chen ◽  
Charles R. Lovell
Keyword(s):  
Electron Donors ◽  
Ortho Position ◽  
Enrichment Cultures ◽  
Bacterium Strain

An anaerobic 2,4,6-tribromophenol debrominating bacterium, strain DSL-1, was isolated from enrichment cultures inoculated with sediment from the burrows of the bromoaromatic-producing marine hemichordates Balanoglossus aurantiacus and Saccoglossus kowalewskyi. DSL-1 preferentially removed ortho-position bromines, resulting in the transient appearance of 2,4-dibromophenol and accumulation of 4-bromophenol. Cell-free extracts and partially purified reductive debrominase preparations from DSL-1 also debrominated 2,4,6-tribromophenol, yielding 2,4-dibromophenol and 4-bromophenol. Both NADH and NADPH stimulated 2,4,6-tribromophenol reduction by partially purified debrominase. These data are consistent with a reductive debromination mechanism. The organic cosubstrate(s) and specific electron donors used by DSL-1 in vivo are currently unknown.Key words: dehalogenation, bromometabolites, bromophenols, hemichordates.

Phyllobacterium Calauticae Sp. Nov. Isolated From a Microaerophilic Veil Transversed by Cable Bacteria in Freshwater Sediment

2021 ◽  
Author(s):  
Jamie J.M. Lustermans ◽  
Jesper Jensen Bjerg ◽  
Andreas Schramm ◽  
Ian P.G. Marshall
Keyword(s):  
Organic Compounds ◽  
Type Strain ◽  
Electron Donors ◽  
Water Phase ◽  
Freshwater Sediment ◽  
Glass Capillary ◽  
Genomic Comparison ◽  
Bacterium Strain ◽  
Suboxic Zone ◽  
Swimming Microorganisms

Abstract Microaerophilic veils of swimming microorganisms form at oxic-anoxic interfaces, most commonly described in sediments where sulfide diffusing out from below meets oxygen diffusing in from the water phase. However, distinctive microaerophilic veils form even when there is a gap between the sulfide and O2 fronts, i.e., a suboxic zone, and suggest that the organisms inhabiting these veils can use electron donors other than sulfide. Suboxic zones are found for example in sediment where cable bacteria spatially separate sulfide and O2 by up to several centimetres. Here we describe the extraction of microorganisms from a microaerophilic veil that formed in cable-bacteria-enriched freshwater sediment using a glass capillary, and the subsequent isolation of a motile, microaerophilic, organoheterotrophic bacterium, strain R2-JLT, unable to oxidize sulfide. Based on phenotypic, phylogenetic, and genomic comparison, we propose strain R2-JLT as a novel Phyllobacterium species, P. calauticae sp. nov.. The type strain is R2-JLT (=LMG 32286T =DSM 112555T). This novel isolate confirms that a wider variety of electron donors, including organic compounds, can fuel the activity of microorganisms in microaerophilic veils.

On the Mechanism of Benzoquinone Penetration and Photoreduction by Whole Cells

1971 ◽  
Vol 26 (6) ◽  
pp. 585-588 ◽  
Author(s):  
H. Gimmler ◽  
M. Avron
Keyword(s):  
Electron Transport ◽  
Cell Membrane ◽  
Photosynthetic Electron Transport ◽  
Electron Acceptors ◽  
Electron Donors ◽  
Porphyridium Cruentum ◽  
Whole Cells ◽  
Time Treatment ◽  
Short Time

Short time treatment of intact Porphyridium cruentum cells with benzoquinone results in changes of the cell membranes, which lead to a higher permeability. This increased permeability allows the measurements of photosynthetic electron transport reactions with various electron donors, ac. ceptors and mediators, which cannot enter untreated cells. The capacity of benzoquinone to act as a Hill - reagent in vivo is interpreted as due to a double action of this compound: changing the permeability of the cells by reacting with the cell membrane coupled with the ability of the unreacted molecules to serve as electron acceptors.

scholarly journals Organic electron donors and terminal electron acceptors structure anaerobic microbial communities and interactions in a permanently stratified sulfidic lake

2021 ◽  
Author(s):  
Connie A. Rojas ◽  
Ana De Santiago Torio ◽  
Serry Park ◽  
Tanja Bosak ◽  
Vanja Klepac-Ceraj
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Communities ◽  
Microbial Community Structure ◽  
Bacterial Communities ◽  
Electron Acceptors ◽  
Electron Donors ◽  
Stratified Lakes ◽  
Enrichment Cultures ◽  
Organic Electron

AbstractThe extent to which nutrients structure microbial communities in permanently stratified lakes is not well understood. This study characterized microbial communities from the anoxic layers of the meromictic and sulfidic Fayetteville Green Lake (FGL), NY, and investigated the roles of organic electron donors and terminal electron acceptors in shaping microbial community structure and interactions. Bacterial communities from the permanently stratified layer below the chemocline (monimolimnion) and from enrichment cultures inoculated by lake sediments were analyzed using 16S rRNA gene sequencing. Results showed that anoxygenic phototrophs dominated microbial communities in the upper monimolimnion (21 m), which harbored little diversity, whereas the most diverse communities resided at the bottom of the lake (~52 m). Organic electron donors explained 54% of the variation in the microbial community structure in aphotic cultures enriched on an array of organic electron donors and different inorganic electron acceptors. Electron acceptors only explained 10% of the variation, but were stronger drivers of community assembly in enrichment cultures supplemented with acetate or butyrate compared to the cultures amended by chitin, lignin or cellulose. We identified a range of habitat generalists and habitat specialists in both the water column and enrichment samples using Levin’s index. Network analyses of interactions among microbial groups revealed Chlorobi and sulfate reducers as central to microbial interactions in the upper monimolimnion, while Syntrophaceae and other fermenting organisms were more important in the lower monimolimnion. The presence of photosynthetic microbes and communities that degrade chitin and cellulose much below the chemocline supported the downward transport of microbes, organic matter and oxidants from the surface and the chemocline. Collectively, our data suggest niche partitioning of bacterial communities by interactions that depend on the availability of different organic electron donors and terminal electron acceptors. Thus, light, as well as the diversity and availability of chemical resources drive community structure and function in FGL, and likely in other stratified, meromictic lakes.

The range of in anisole derivatives. An indicator of torsion and compression of the methoxy group

1985 ◽  
Vol 63 (3) ◽  
pp. 782-786 ◽  
Author(s):  
Ted Schaefer ◽  
Salman R. Salman ◽  
Timothy A. Wildman ◽  
Glenn H. Penner
Keyword(s):  
Methoxy Group ◽  
Bond Angle ◽  
Average Distance ◽  
Electron Donors ◽  
Spin Coupling ◽  
Ortho Position ◽  
Coupling Constant ◽  
Spin Coupling Constant ◽  
Methyl Group ◽  
Spin Spin Coupling

In a series of anisole derivatives, [Formula: see text], the spin–spin coupling constant between the methyl protons and the ring proton in the ortho position, ranges from −0.23 to −0.38 Hz when the methyl group lies cis to the ortho C—H bond. 5J, as a proximate coupling, is sensitive to the average distance between the coupled protons. Its variation with substituent can be rationalized in terms of torsion about the Csp2—O bond and changes in the bond angles near the methoxy moiety. The theoretical 5J numbers can be empirically reproduced by a cos4 ψ function, where ψ is the angle by which the methoxy group twists out of the benzene plane. In general, large ortho substituents cause an increase in the magnitude of 5J (bond angle changes), strong π electron donors in the para position cause a decrease in the magnitude of 5J (increased torsional freedom), and π electron acceptors do the opposite (decreased torsions).

scholarly journals Desulfovibrio alkalitolerans sp. nov., a novel alkalitolerant, sulphate-reducing bacterium isolated from district heating water

2006 ◽  
Vol 56 (5) ◽  
pp. 1019-1024 ◽  
Author(s):  
Lone Abildgaard ◽  
Marie Bank Nielsen ◽  
Kasper Urup Kjeldsen ◽  
Kjeld Ingvorsen
Keyword(s):  
Electron Acceptor ◽  
Genomic Dna ◽  
Type Strain ◽  
Novel Species ◽  
District Heating ◽  
Electron Acceptors ◽  
Electron Donors ◽  
Heating Water ◽  
Bacterium Strain

A novel alkalitolerant, sulphate-reducing bacterium (strain RT2T) was isolated from alkaline district heating water. Strain RT2T was a motile vibrio (0.5–0.8 μm wide and 1.4–1.9 μm long) and grew at pH 6.9–9.9 (optimum at pH 9.0–9.4) and at 16–47 °C (optimum at 43 °C). The genomic DNA G+C content was 64.7 mol%. A limited number of compounds were used as electron donors with sulphate as electron acceptor, including lactate, pyruvate, formate and hydrogen/acetate. Sulphite and thiosulphate also served as electron acceptors. Based on physiological and genotypic properties, the isolate was considered to represent a novel species of the genus Desulfovibrio, for which the name Desulfovibrio alkalitolerans sp. nov. is proposed. The type strain is RT2T (=DSM 16529T=JCM 12612T). The strain is the first alkali-tolerant member of the genus Desulfovibrio to be described.

scholarly journals Metagenomic- and Cultivation-Based Exploration of Anaerobic Chloroform Biotransformation in Hypersaline Sediments as Natural Source of Chloromethanes

2020 ◽  
Vol 8 (5) ◽  
pp. 665
Author(s):  
Peng Peng ◽  
Yue Lu ◽  
Tom N.P. Bosma ◽  
Ivonne Nijenhuis ◽  
Bart Nijsse ◽  
...  
Keyword(s):  
Vitamin B12 ◽  
Reductive Dechlorination ◽  
Electron Donors ◽  
Natural Source ◽  
Hypersaline Lake ◽  
Reductive Dehalogenase ◽  
Enrichment Cultures ◽  
Cobalamin Biosynthesis ◽  
Abiotic Control ◽  
Hypersaline Sediments

Chloroform (CF) is an environmental contaminant that can be naturally formed in various environments ranging from forest soils to salt lakes. Here we investigated CF removal potential in sediments obtained from hypersaline lakes in Western Australia. Reductive dechlorination of CF to dichloromethane (DCM) was observed in enrichment cultures derived from sediments of Lake Strawbridge, which has been reported as a natural source of CF. No CF removal was observed in abiotic control cultures without artificial electron donors, indicating biotic CF dechlorination in the enrichment cultures. Increasing vitamin B12 concentration from 0.04 to 4 µM in enrichment cultures enhanced CF removal and reduced DCM formation. In cultures amended with 4 µM vitamin B12 and 13C labelled CF, formation of 13CO2 was detected. Known organohalide-respiring bacteria and reductive dehalogenase genes were neither detected using quantitative PCR nor metagenomic analysis of the enrichment cultures. Rather, members of the order Clostridiales, known to co-metabolically transform CF to DCM and CO2, were detected. Accordingly, metagenome-assembled genomes of Clostridiales encoded enzymatic repertoires for the Wood-Ljungdahl pathway and cobalamin biosynthesis, which are known to be involved in fortuitous and nonspecific CF transformation. This study indicates that hypersaline lake microbiomes may act as a filter to reduce CF emission to the atmosphere.

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