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Anaerobic respiration

Xiao Deng, Naoshi Dohmae, Kenneth H Nealson, Kazuhito Hashimoto, Akihiro Okamoto
Bacterial reduction of oxidized sulfur species (OSS) is critical for energy production in anaerobic marine subsurfaces. In organic-poor sediments, H2 has been considered as a major energy source for bacterial respiration. We identified outer-membrane cytochromes (OMCs) that are broadly conserved in sediment OSS-respiring bacteria and enable cells to directly use electrons from insoluble minerals via extracellular electron transport. Biochemical, transcriptomic, and microscopic analyses revealed that the identified OMCs were highly expressed on the surface of cells and nanofilaments in response to electron donor limitation...
February 2018: Science Advances
Anja Baufeld, Jens Vanselow
BACKGROUND: The LH-induced folliculo-luteal transformation is connected with alterations of the gene expression profile in cells of the granulosa layer. It has been described that hypoxic conditions occur during luteinization, thus favoring the formation of L-lactate within the follicle. Despite being a product of anaerobic respiration, L-lactate has been shown to act as a signaling molecule affecting gene expression in neuronal cells. During the present study, we tested the hypothesis that L-lactate may influence differentiation of follicular granulosa cells (GC)...
February 20, 2018: Reproductive Biology and Endocrinology: RB&E
María J Torres, Sergio Avila, Eulogio J Bedmar, María J Delgado
The alfalfa endosymbiont Ensifer meliloti strain1021 is known to be an incomplete denitrifier due to its inability to grow anoxically using nitrate as respiratory substrate to produce ATP and grow under anoxic conditions. Although this bacterium contains and expresses the complete set of denitrification genes napEFDABC, nirK, norECBQD and nosRZDFYLX encoding the periplasmic nitrate reductase (Nap), Cu-containing nitrite reductase (NirK), c-type nitric oxide (cNor) and nitrous oxide reductase (Nos), respectively, the reasons of its inability to grow under anoxic conditions are still very poorly understood...
February 16, 2018: FEMS Microbiology Letters
Uta Wille, Joses Nathanael, Luke Gamon, Meike Cordes, Paul Rablen, Thomas Bally, Katharina Fromm, Bernd Giese
Nature uses proteins as medium for long-distance electron transfer (ET) to carry out redox reactions in distant compartments. This ET occurs either by a single-step superexchange or through a multi-step charge hopping process, which uses side chains of amino acids as stepping stones. In this study we demonstrate that Phe can act as a relay amino acid for long-distance electron hole transfer through peptides. The considerably increased susceptibility of the aromatic ring to oxidation is caused by the lone pairs of neighbouring amide carbonyl groups, which stabilize the Phe radical cation...
February 19, 2018: Chembiochem: a European Journal of Chemical Biology
E N Frolov, K S Zayulina, D S Kopitsyn, I V Kublanov, E A Bonch-Osmolovskaya, N A Chernyh
An anaerobic sulfate-reducing micro-organism, strain 3408-1T , was isolated from a terrestrial hot spring in Kamchatka peninsula (Russia). The cells were spore-forming rods with a Gram-positive type of cell wall. The new isolate was a moderately thermoacidophilic anaerobe able to grow either by sulfate or thiosulfate respiration with H2 or formate as substrates, or by fermenting yeast extract, maltose, sucrose, glucose and pyruvate. The fermentation products were acetate, CO2 and H2. The pH range for growth was 2...
January 25, 2018: International Journal of Systematic and Evolutionary Microbiology
Shiyu Rachel Wang, Daniela Di Iorio, Wei-Jun Cai, Charles S Hopkinson
We conducted a free-water mass balance-based study to address the rate of metabolism and net carbon exchange for the tidal wetland and estuarine portion of the coastal ocean and the uncertainties associated with this approach were assessed. We measured open water diurnal O2 and dissolved inorganic carbon (DIC) dynamics seasonally in a salt marsh-estuary in Georgia, U.S.A. with a focus on the marsh-estuary linkage associated with tidal flooding. We observed that the overall estuarine system was a net source of CO2 to the atmosphere and coastal ocean and a net sink for oceanic and atmospheric O2 ...
January 2018: Limnology and Oceanography
Daniel B Mills, Warren R Francis, Sergio Vargas, Morten Larsen, Coen Ph Elemans, Donald E Canfield, Gert Wörheide
Animals have a carefully orchestrated relationship with oxygen. When exposed to low environmental oxygen concentrations, and during periods of increased energy expenditure, animals maintain cellular oxygen homeostasis by enhancing internal oxygen delivery, and by enabling the anaerobic production of ATP. These low-oxygen responses are thought to be controlled universally across animals by the hypoxia-inducible factor (HIF). We find, however, that sponge and ctenophore genomes lack key components of the HIF pathway...
February 6, 2018: ELife
Dongbo Cai, Shiying Hu, Yaozhong Chen, Li Liu, Shihui Yang, Xin Ma, Shouwen Chen
Poly-γ-glutamic acid is a multi-functional biopolymer with various applications. ATP supply plays an important role in poly-γ-glutamic acid (γ-PGA) synthesis. Global anaerobic regulator Fnr plays a key role in anaerobic adaptation and nitrate respiration, which might affect ATP generation during γ-PGA synthesis. In this study, we have improved γ-PGA production by overexpression of Fnr in Bacillus licheniformis WX-02. First, the gene fnr was knocked out in WX-02, and the γ-PGA yields have no significant differences between WX-02 and the fnr-deficient strain WXΔfnr in the medium without nitrate (BFC medium)...
February 1, 2018: Applied Biochemistry and Biotechnology
Mohammad Khalid Al-Sadoon, Bilal A Paray, Hassan A Rudayni
The oxygen consumption rate [Formula: see text] and lactate production of the Amphisbaenian worm lizard Diplometopon zarudnyi were measured at temperatures ranging from 15 °C to 35 °C at 5 °C intervals. The [Formula: see text] was significantly different between resting and active states at any specified temperature, while the average value at the resting state generally rose with increased temperature from 15 °C (0.05 ml O2/g/h) to 25 °C (0.111 ml O2/g/h). The aerobic respiration scopes at resting and active states were also significantly different...
January 2018: Saudi Journal of Biological Sciences
Brittany D Bennett, Kaitlyn E Redford, Jeffrey A Gralnick
Shewanella oneidensis strain MR-1 is a versatile bacterium capable of respiring extracellular, insoluble ferric oxide minerals under anaerobic conditions. The respiration of iron minerals results in the production of soluble ferrous ions, which at high concentrations are toxic to living organisms. It is not fully understood how Fe2+ is toxic to cells anaerobically; nor is it fully understood how S. oneidensis is able to resist high levels of Fe2+ Here we describe the results of a transposon-mutant screen and subsequent deletion of the genes clpX and clpP in S...
January 29, 2018: Journal of Bacteriology
Bat-Erdene Jugder, Karl A P Payne, Karl Fisher, Susanne Bohl, Helene Lebhar, Mike Manefield, Matthew Lee, David Leys, Christopher P Marquis
Reductive dehalogenases (RDase) are key enzymes involved in the respiratory process of anaerobic organohalide respiring bacteria (ORB). Heterologous expression of respiratory RDases is desirable for structural and functional studies, however there are few reports of successful expression of these enzymes. Dehalobacter sp. strain UNSWDHB is an ORB, whose preferred electron acceptor is chloroform. This study describes efforts to express recombinant reductive dehalogenase (TmrA), derived from UNSWDHB, using the heterologous hosts Escherichia coli and Bacillus megaterium...
January 24, 2018: ACS Chemical Biology
Lizhu Hou, Bill X Hu, Mengmeng He, Xue Xu, Wenjing Zhang
To enhance denitrification in a process of solute infiltration through a soil, a two-section mixed-medium soil infiltration system (TMSIS) for urban non-point pollution was developed. The artificial aerobic respiration and nitrification took place in the upper aerobic section (AES), while grass powders and sawdust were mixed in the bottom anaerobic section (ANS) to supply organic carbon source for denitrification bacteria, and the reduction was increased by iron addition in the ANS. Measured resident concentrations from the bottom of each ANS column were assumed to represent mean values averaged over the column cross-sectional area...
January 23, 2018: Environmental Science and Pollution Research International
Ting Duan, Chenchen Shi, Jing Zhou, Xiao Lv, Yongli Li, Yiping Luo
This study aimed to test the hypothesis that the aerial survival of the northern snakehead is involved not only with suprabranchial chamber respiration but also with physiological regulations. The aerial survival time and oxygen consumption rate (VO2) were determined in snakeheads with either normal or injured suprabranchial organs. Some hematological and biochemical parameters were assessed during aerial exposure. The results showed that resting VO2 decreased when switching from water to air in both the control and the suprabranchial organ-injured fish, with decreases of 22...
January 22, 2018: Biology Open
Rhiannon C G Creasey, A Bernardus Mostert, Tuan Nguyen, Bernardino Virdis, Stefano Freguia, Bronwyn Laycock
Electron transfer is central to cellular life, from photosynthesis to respiration. In the case of anaerobic respiration, some microbes have extracellular appendages that can be utilised to transport electrons over great distances. Two model organisms heavily studied in this arena are Shewanella oneidensis and Geobacter sulfurreducens. There is some debate over how, in particular, the Geobacter sulfurreducens nanowires (formed from pilin nanofilaments) are capable of achieving the impressive feats of natural conductivity that they display...
January 18, 2018: Acta Biomaterialia
Dezhuo Pan, Lingxia Wang, Fanglin Tan, Si Lu, Xiaojie Lv, Madiha Zaynab, Chi-Lien Cheng, Yakubu Saddeeq Abubakar, Shipin Chen, Wei Chen
The mangrove Kandelia candel (L.) Druce experiences daily flooding cycles. To explore the molecular mechanism underlying the physiological adaptation of K. candel to flooding, the potential role of protein phosphorylation in flooding responses was investigated by a large-scale quantitative phosphoproteomic analysis using isobaric tag for relative and absolute quantitation. Total 2141 unique phosphopeptides and 2603 non-redundant phosphorylation sites were identified from 1516 phosphoproteins in K. candel leaves...
January 15, 2018: Journal of Proteomics
Paul Kaufmann, Benjamin R Duffus, Biljana Mitrova, Chantal Iobbi-Nivol, Christian Teutloff, Manfred Nimtz, Lothar Jänsch, Ulla Wollenberger, Silke Leimkühler
The well-studied enterobacterium Escherichia coli present in the human gut is able to reduce TMAO to trimethylamine (TMA) during anaerobic respiration. The TMAO reductase TorA is a monomeric, bis-molybdopterin guanine dinucleotide (bis-MGD) cofactor-containing enzyme belonging to the dimethylsulfoxide (DMSO) reductase family of molybdoenzymes. We report on a system for the in vitro reconstitution of TorA with molybdenum cofactors (Moco) from different sources. Higher TMAO reductase activities for TorA were obtained when using Moco-sources containing a sulfido ligand at the molybdenum atom...
January 15, 2018: Biochemistry
Merve S Zeden, Christopher F Schuster, Lisa Bowman, Qiyun Zhong, Huw D Williams, Angelika Gründling
Cyclic di-adenosine monophosphate (c-di-AMP) is a recently discovered signaling molecule important for the survival of Firmicutes, a large bacterial group that includes notable pathogens such as Staphylococcus aureus. However, the exact role of this molecule has not been identified. dacA, the S. aureus gene encoding the diadenylate cyclase enzyme required for c-di-AMP production, cannot be deleted when bacterial cells are grown in rich medium, indicating that c-di-AMP is required for growth in this condition...
January 11, 2018: Journal of Biological Chemistry
Sawa Wasai, Nanako Kanno, Katsumi Matsuura, Shin Haruta
Bacteria in natural environments are frequently exposed to nutrient starvation and survive against environmental stresses under non-growing conditions. In order to determine the energetic influence on survivability during starvation, changes in salt tolerance were investigated using the purple photosynthetic bacterium Rhodopseudomonas palustris after carbon starvation under photosynthetic conditions in comparison with anaerobic and aerobic dark conditions. Tolerance to a treatment with high concentration of salt (2...
January 6, 2018: Microorganisms
Liying Wang, Li Ye, Yaqin Yu, Chuanyong Jing
Anaerobic microbiological antimonate [Sb(V)] respiration is a newly discovered process regulating the Sb redox transformation in soils. However, little is known about the role microbiological Sb(V) respiration plays in the fate of Sb in the subsurface, especially in the presence of sulfate and electron shuttles. Herein, we successfully enriched a Sb(V) reducing microbiota (SbRM) from the subsurface near an active Sb mine. SbRM was dominated by genus Alkaliphilus (18-36%), Clostridiaceae (17-18%), Tissierella (24-27%), and Lysinibacillus (16-37%)...
January 9, 2018: Environmental Science & Technology
Yang Lu, Hui Li, Yue Geng
δ-Tocopherol (δ-TOH) is a form of vitamin E with higher bioactivity. In this study, we studied the bioactivity of δ-TOH using the IC50 of δ-TOH on RAW264.7 (80 μM) and K562 (110 μM) cells. We compared the differential metabolites from the cell lines with and without δ-TOH treatment by 1H-NMR metabonomics analysis. It was found that δ-TOH affected the protein biosynthesis, betaine metabolism, and urea cycle in various ways in both cell lines. Metabolic levels of the cell lines were changed after treatment with δ-TOH as differential metabolites were produced...
January 9, 2018: Journal of Agricultural and Food Chemistry
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