Unusual reactions involved in anaerobic metabolism of phenolic compounds

2005 ◽  
Vol 386 (10) ◽  
pp. 989-997 ◽  
Author(s):  
Matthias Boll ◽  
Georg Fuchs
Keyword(s):  
Phenolic Compounds ◽  
Molecular Oxygen ◽  
Anaerobic Degradation ◽  
Anaerobic Metabolism ◽  
Anaerobic Bacteria ◽  
Aerobic Bacteria ◽  
Reduction Mechanism ◽  
Mechanistic Studies ◽  
Aromatic Metabolism ◽  
Aromatic Product

AbstractAerobic bacteria use molecular oxygen as a common co-substrate for key enzymes of aromatic metabolism. In contrast, in anaerobes all oxygen-dependent reactions are replaced by a set of alternative enzymatic processes. The anaerobic degradation of phenol to a non-aromatic product involves enzymatic processes that are uniquely found in the aromatic metabolism of anaerobic bacteria: (i) ATP-dependent phenol carboxylation to 4-hydroxybenzoate via a phenylphosphate intermediate (biological Kolbe-Schmitt carboxylation); (ii) reductive dehydroxylation of 4-hydroxybenzoyl-CoA to benzoyl-CoA; and (iii) ATP-dependent reductive dearomatization of the key intermediate benzoyl-CoA in a ‘Birch-like’ reduction mechanism. This review summarizes the results of recent mechanistic studies of the enzymes involved in these three key reactions.

Study of the role of Chlamydia, Mycoplasma, Ureaplasma and other microaerophilic and aerobic bacteria in uterine infections of mares with reproductive disorders

2003 ◽  
Vol 51 (1) ◽  
pp. 45-52 ◽  
Author(s):  
László Szeredi ◽  
M. Tenk ◽  
I. Schiller ◽  
Keyword(s):  
Pathogenic Bacteria ◽  
Anaerobic Bacteria ◽  
Aerobic Bacteria ◽  
Relative Importance ◽  
Reproductive Disorders ◽  
Taylorella Equigenitalis

In six healthy mares and 24 mares showing reproductive disorders swab samples were taken from the fossa clitoridis to isolate Taylorella equigenitalis, and from the uterus to isolate mycoplasmas, ureaplasmas and other aerobic bacteria. Swab samples were also taken from the uterus for Chlamydiaantigen ELISA and ChlamydiaPCR studies. The uterus of 27 mares was examined cytologically, and biopsy samples were taken from the endometrium for histological examinations and for immunohistochemical examinations aimed at the detection of chlamydiae. T. equigenitalis, mycoplasmas, ureaplasmas and chlamydiae could not be detected from any of the mares examined. Aerobic facultative pathogenic bacteria were isolated from mares with endometritis in four cases. In 18 out of 22 mares with endometritis (82%) no infective agents could be demonstrated. Further studies are needed to elucidate the relative importance of non-infectious causes of endometritis and of anaerobic bacteria often detectable in the uterus in the aetiology of the reproductive disorders observed.

Activation of Acetone and Other Simple Ketones in Anaerobic Bacteria

2016 ◽  
Vol 26 (1-3) ◽  
pp. 152-164 ◽  
Author(s):  
Johann Heider ◽  
Karola Schühle ◽  
Jasmin Frey ◽  
Bernhard Schink
Keyword(s):  
Energy Supply ◽  
Anaerobic Bacteria ◽  
Aerobic Bacteria ◽  
Metabolic Intermediate ◽  
Present Evidence ◽  
Sulfate Reducing ◽  
Different Types ◽  
Subsequent Degradation ◽  
Reducing Bacteria ◽  
Hydrolysis Of

Acetone and other ketones are activated for subsequent degradation through carboxylation by many nitrate-reducing, phototrophic, and obligately aerobic bacteria. Acetone carboxylation leads to acetoacetate, which is subsequently activated to a thioester and degraded via thiolysis. Two different types of acetone carboxylases have been described, which require either 2 or 4 ATP equivalents as an energy supply for the carboxylation reaction. Both enzymes appear to combine acetone enolphosphate with carbonic phosphate to form acetoacetate. A similar but more complex enzyme is known to carboxylate the aromatic ketone acetophenone, a metabolic intermediate in anaerobic ethylbenzene metabolism in denitrifying bacteria, with simultaneous hydrolysis of 2 ATP to 2 ADP. Obligately anaerobic sulfate-reducing bacteria activate acetone to a four-carbon compound as well, but via a different process than bicarbonate- or CO<sub>2</sub>-dependent carboxylation. The present evidence indicates that either carbon monoxide or a formyl residue is used as a cosubstrate, and that the overall ATP expenditure of this pathway is substantially lower than in the known acetone carboxylase reactions.

The production of reactive oxygen species enhanced with the reduction of menadione by active thioredoxin reductase

Metallomics ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1490-1497 ◽  
Author(s):  
Jing Li ◽  
Xin Zuo ◽  
Ping Cheng ◽  
Xiaoyuan Ren ◽  
Shibo Sun ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Molecular Oxygen ◽  
Thioredoxin Reductase ◽  
Reactive Oxygen ◽  
Semiquinone Radical ◽  
Ros Production ◽  
Oxygen Species ◽  
Reduction Mechanism ◽  
Radical Intermediate ◽  
Electron Reduction

TXNRD1 participates in the ROS production with menadione by a one-electron reduction mechanism. TXNRD1 transfers electrons from NADPH to menadione to yield a semiquinone radical intermediate, which reacts with molecular oxygen to generate ROS.

Direct Synthesis of Enones by Visible-Light-Promoted Oxygenation of Trisubstituted Olefins Using Molecular Oxygen

Synlett ◽  
2020 ◽  
Vol 31 (14) ◽  
pp. 1372-1377
Author(s):  
Shinji Harada ◽  
Daiki Matsuda ◽  
Takahiro Morikawa ◽  
Atsushi Nishida
Keyword(s):  
Visible Light ◽  
Molecular Oxygen ◽  
Active Oxygen Species ◽  
Direct Synthesis ◽  
Reaction System ◽  
Active Oxygen ◽  
Oxygen Species ◽  
Mechanistic Studies ◽  
Trisubstituted Olefins ◽  
One Step

A one-step synthesis of enones from olefins is described. The reaction was performed under visible-light irradiation in the presence of molecular oxygen and a photocatalyst. The reaction proceeded with various types of trisubstituted olefins to give enones in good yields with high regioselectivity. In particular, oxygen- and nitrogen-containing functional groups, heteroaromatic rings, and cyclopropanes were tolerated. Mechanistic studies and previous reports indicated that the active oxygen species generated in the reaction system is singlet oxygen.

scholarly journals Airborne non-sporeforming anaerobic bacteria

1980 ◽  
Vol 84 (2) ◽  
pp. 181-189 ◽  
Author(s):  
A. Hambraeus ◽  
E. Benediktsdóttir
Keyword(s):  
Total Hip Replacement ◽  
Hip Replacement ◽  
Anaerobic Bacteria ◽  
Aerobic Bacteria ◽  
Postoperative Infections ◽  
Total Hip ◽  
Airborne Infection

A large proportion of postoperative infections after clean surgery are thought to be exogenous. For aerobic bacteria different routes of transmission have been thoroughly studied. Airborne infection has been considered very important in infections after total hip replacement (Charnley, 1972). Anaerobic non-sporing bacteria have been found in deep late infections after total hip replacement (Kamme et al. 1974; Schwan et al. 1977; Petrini, Nord & Welin-Berger, 1978). However, infections caused by anaerobic bacteria have been considered endogenous, and little is known about the routes of transmission for these bacteria.

Isolation and Characterization of Paraquat-Degrading Extracellular Humus-Reducing Bacteria from Vegetable Field

2013 ◽  
Vol 807-809 ◽  
pp. 1026-1030 ◽  
Author(s):  
Chun Yuan Wu ◽  
Jin Kun Liu ◽  
Shan Shan Chen ◽  
Xiao Deng ◽  
Qin Fen Li
Keyword(s):  
Electron Acceptor ◽  
Anaerobic Degradation ◽  
Anaerobic Bacteria ◽  
Organic Substrate ◽  
Isolation And Characterization ◽  
Vegetable Soil ◽  
Pure Cultures ◽  
Degradation Activity ◽  
Facultative Anaerobic Bacteria ◽  
Reducing Bacteria

The aim of this paper is to isolate pure cultures that are capable of degrading paraquat (PQ) anaerobically with humic substances (humus) as the sole electron acceptor. Three facultative anaerobic bacteria (PQ-1, PQ-2, and PQ-3) were successively isolated from vegetable soil in Sanya city, China, via enrichment procedure with PQ and anthraquinone-2,6-disulphonate (AQDS) under anaerobic conditions. Batch experiments were conducted to investigate isolates PQ anaerobic degradation activity. Results showed that three strains were all capable of degrading PQ directly with AQDS as the sole electron acceptor (18.6% removal within 48h), and the microbial process might be AQDS dependent. The addition of low molecular weight organic substrate, such as sucrose, could enhance the anaerobic degradation of PQ from 18.6% to 34.2%, and the degradation rate reached 100% after 5-day incubation. This study was the first paper reporting that pure cultures have the ability to anaerobically degrade PQ with AQDS as the sole electron acceptor.

Biosorption of Precious Metal Ions by Magnetically Activated Sludge Cultured Bacteria

2012 ◽  
Vol 152-154 ◽  
pp. 46-51
Author(s):  
Fang Cai ◽  
Jin Sheng Sun ◽  
Ting Ting Zhao ◽  
Jing Li
Keyword(s):  
Activated Sludge ◽  
Metal Ions ◽  
Precious Metal ◽  
High Selectivity ◽  
Anaerobic Bacteria ◽  
Precious Metals ◽  
Aerobic Bacteria ◽  
Adsorption Effect ◽  
Precious Metal Ions ◽  
Cultured Bacteria

Although biosorption for reclaiming single precious metal was frequently reported, the actual subsistent adsorptive competition among different metal ions sometimes shows diverging reinforcement or prohibition for different species. This study tries to screen bacteria that are able to absorb certain precious metals with high selectivity under competitive conditions. The activated sludge was cultivated from enrichment by magnetotactic bacteria medium proposed by Blakemore. Then four microbes, microaerobic bacteria(A) acclimated micro-aerobic bacteria (B), anaerobic bacteria(C) and acclimated anaerobic bacteria(D) were obtained for the following adsorption experiments. The four microbes have high removal efficiency of Au3+ both in its unitary and Au3+-Cu2+binary system. The microaerobic bacteria (B) are good metal catchers and carriers for the uptake of gold in aquatic solution with coexistence of copper. In Pd2+-Cu2+system, there is a collaborative adsorption effect, especially on (B).

Seasonal variation in nitrogen fixation, associated microbial populations, and carbohydrates in roots and rhizomes of Typha latifolia (Typhaceae)

1984 ◽  
Vol 62 (9) ◽  
pp. 1965-1967 ◽  
Author(s):  
David D. Biesboer
Keyword(s):  
Nitrogen Fixation ◽  
Nitrogenase Activity ◽  
Anaerobic Bacteria ◽  
Typha Latifolia ◽  
Root Surface ◽  
Microbial Populations ◽  
Aerobic Bacteria ◽  
Free Sugar ◽  
Fixation Rate ◽  
Reduction Assay

Seasonal changes in nitrogen fixation, numbers of nitrogen-fixing bacteria associated with the roots, and rhizome–root carbohydrates were studied for the broad-leaved cattail, Typha latifolia L. Populations of anaerobic and aerobic diazotrophic bacteria were present on the root surface. Anaerobic bacteria predominated in the diazotrophic association, were more active in the acetylene reduction assay, and generally outnumbered aerobic bacteria by 2 to 1 during maximum rates of seasonal nitrogen fixation. The observed maximum nitrogen fixation rate coincided closely with reproductive development in Typha and peak microbial populations. Starch levels in rhizomes were nearly depleted during the middle of the growing season, whereas free sugar concentrations remained stable. Sugar concentrations in the roots increased rapidly during rhizome–root growth and decreased rapidly prior to peak nitrogenase activity.

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