THE EFFECT OF REDOX POTENTIAL ON THE GROWTH OF <i>CLOSTRIDIUM WELCHII</i> STRAINS ISOLATED FROM HORSE MUSCLE

Barnes, Ella M.; Ingram, M.

doi:10.1111/j.1365-2672.1956.tb00055.x

Cited by 53 publications

(10 citation statements)

References 7 publications

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“…Cell extracts of M. thermoacetica can produce cysteine from cystine by enzymatic reduction with molecular hydrogen as electron donor (44). Results described herein thus provide strong evidence that both cytochrome bd oxidase and cysteine (and, by inference, CysK) play significant roles in dioxygen tolerance and oxidative stress protection of M. thermoacetica by scavenging dioxygen and/or maintaining a low intracellular reduction potential, both of which are known to be essential for growth of many anaerobic bacteria (1,72). R.S.-D. thanks the Chemistry Department of Babesh-Bolyai University, Cluj-Napoca, Romania, for a leave of absence.…”

Section: Discussionmentioning

confidence: 68%

Cytochrome bd Oxidase, Oxidative Stress, and Dioxygen Tolerance of the Strictly Anaerobic Bacterium Moorella thermoacetica

Das¹,

Silaghi-Dumitrescu

Ljungdahl³

et al. 2005

J Bacteriol

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The gram-positive, thermophilic, acetogenic bacterium Moorella thermoacetica can reduce CO 2 to acetate via the Wood-Ljungdahl (acetyl coenzyme A synthesis) pathway. This report demonstrates that, despite its classification as a strict anaerobe, M. thermoacetica contains a membrane-bound cytochrome bd oxidase that can catalyze reduction of low levels of dioxygen. Whole-cell suspensions of M. thermoacetica had significant endogenous O 2 uptake activity, and this activity was increased in the presence of methanol or CO, which are substrates in the Wood-Ljungdahl pathway. Cyanide and azide strongly (ϳ70%) inhibited both the endogenous and CO/methanol-dependent O 2 uptake. UV-visible light absorption and electron paramagnetic resonance spectra of n-dodecyl-␤-maltoside extracts of M. thermoacetica membranes showed the presence of a cytochrome bd oxidase complex containing cytochrome b 561 , cytochrome b 595 , and cytochrome d (chlorin). Subunits I and II of the bd oxidase were identified by N-terminal amino acid sequencing. The M. thermoacetica cytochrome bd oxidase exhibited cyanide-sensitive quinol oxidase activity. The M. thermoacetica cytochrome bd (cyd) operon consists of four genes, encoding subunits I and II along with two ABC-type transporter proteins, homologs of which in other bacteria are required for assembly of the bd complex. The level of this cyd operon transcript was significantly increased when M. thermoacetica was grown in the absence of added reducing agent (cysteine ؉ H 2 S). Expression of a 35-kDa cytosolic protein, identified as a cysteine synthase (CysK), was also induced by the nonreducing growth conditions. The combined evidence indicates that cytochrome bd oxidase and cysteine synthase protect against oxidative stress and contribute to the limited dioxygen tolerance of M. thermoacetica.Dioxygen is the preferred electron sink in the respiratory chain of most aerobic bacteria (58). Cytochrome oxidases are the membrane-bound, terminal components of the dioxygendependent respiratory chain, which reduces dioxygen to water with formation of pH and potential gradients (6, 45). Two main types of respiratory cytochrome oxidases are known in bacteria: the heme/copper oxidases (cytochrome aa 3 , cytochrome caa 3 oxidase, and cytochrome bo oxidase), and the heme-only cytochrome bd quinol oxidase, which is associated with microaerobic dioxygen respiration (24,56,59,62). Cytochrome bd oxidases purified from aerobic bacteria have been characterized as 1:1 heterodimers of two integral membrane proteins referred to as subunits I and II (35,55). The heterodimers contain three heme components: a low-spin heme, b 558 , and two high-spin hemes, b 595 and d. In the genomes of Escherichia coli (31) and Azotobacter vinelandii (41), subunits I and II are encoded by cydA and cydB, respectively, of the cytochrome bd (cyd) operon. Two ABC-type transporter proteins, CydD and CydC, are typically required for assembly of the cytochrome bd complex in both gram-positive and gram-negative aerobic bacteria (14, 60). Aerobic r...

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Section: Discussionmentioning

confidence: 68%

Cytochrome bd Oxidase, Oxidative Stress, and Dioxygen Tolerance of the Strictly Anaerobic Bacterium Moorella thermoacetica

Das¹,

Silaghi-Dumitrescu

Ljungdahl³

et al. 2005

J Bacteriol

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“…The apparatus and method used for following Eh values of each culture were adapted from those described by Barnes & Ingram (1956). The culture vessel was fitted with 3 platinum electrodes (Electronic Instruments Ltd., Richmond, Surrey), gas inlet and outlet tubes, an inoculation port and an agar bridge containing saturated KC1 a connected to a standard calomel half cell through a saturated KCl reservoir.…”

Section: Redox Potential Experimentsmentioning

confidence: 99%

“…whereas Barnes & Ingram (1956) obtained a limiting Eh value of +230 to +250 mv at pH 6.0 for several strains isolated from horse muscle. It is not clear whether such differences in behaviour are due to strain variation or to the nature of the growth medium.…”

mentioning

confidence: 94%

Combined Effect of Salt Concentration and Redox Potential of the Medium on the Initiation of Vegetative Growth by Clostridium welchii

Mead¹

1969

Journal of Applied Bacteriology

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Four strains of Clostridium welchii grew in a medium containing 6 % (w/v) of NaCl within 14 days at 37". In one instance growth was obtained with 7 % of NaCl from a large, but not a small, inoculum. Three of the strains grew from a large inoculum in the presence of 0.6 % of NaCl at Eh values of + 194 to + 238 mv. In a medium containing 5 % of NaCl no growth occurred unless the Eh level was considerably reduced. The fourth strain was less affected until the NaCl concentration was increased to 6 %.

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“…However, the concept of direct oxygen toxicity of anaerobes has not been supported by all investigators (7,18). It has been suggested that upper Eh limits exist, above which many anaerobes will not grow (3,6,20,22).…”

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confidence: 99%

Effect of reducing agents on oxidation-reduction potential and the outgrowth of Clostridium botulinum type E spores

Smith¹,

Pierson²

1979

Appl Environ Microbiol

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Oxidation-reduction potential (Eh) levels were measured and standardized to pH 7 (Eh7) for Trypticase soy broth containing various concentrations of reducing agents. Prereduced Trypticase soy broth with no added reducing agents exhibited a potential of-141 mV. Ascorbic acid at 0.2 to 0.005% and sodium thioglycolate at concentrations below 0.05% produced an Eh7 higher than the prereduced Trypticase soy broth containing no added reducing agents. The addition of cysteine hydrochloride, 2-mercaptoethanol, and sodium formaldehyde sulfoxylate to prereduced Trypticase soy broth resulted in a reduction of Eh7 compared to the system without added reducing agents. The order ofrelative reducing intensity (from highest to lowest) for the reducing agents when comparing molar concentration was: sodium formaldehyde sulfoxylate, 2-mercaptoethanol, cysteine hydrochloride, sodium thioglycolate, and ascorbic acid. Optimal growth of the test organism occurred at low Eh7 and low concentration of the reducing agents. A direct correlation existed between growth of the test organism and-Eh7 x-log concentration of the reducing agent.

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THE EFFECT OF REDOX POTENTIAL ON THE GROWTH OF CLOSTRIDIUM WELCHII STRAINS ISOLATED FROM HORSE MUSCLE

Cited by 53 publications

References 7 publications

Cytochrome bd Oxidase, Oxidative Stress, and Dioxygen Tolerance of the Strictly Anaerobic Bacterium Moorella thermoacetica

Cytochrome bd Oxidase, Oxidative Stress, and Dioxygen Tolerance of the Strictly Anaerobic Bacterium Moorella thermoacetica

Combined Effect of Salt Concentration and Redox Potential of the Medium on the Initiation of Vegetative Growth by Clostridium welchii

Effect of reducing agents on oxidation-reduction potential and the outgrowth of Clostridium botulinum type E spores

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