Oxygen Affinities of the Hydrogenosome-containing Protozoa Tritrichomonas foetus and Dasytricha ruminantium, and Two Aerobic Protozoa, Determined by Bacterial Bioluminescence

Lloyd, David; Williams, Judith L.; Yarlett, Nigel; Williams, Alan G.

doi:10.1099/00221287-128-5-1019

Cited by 15 publications

(17 citation statements)

References 19 publications

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“…0001-6601 O 1991 SGM metabolites have been partially characterized ( Yarlett et al, 1981( Yarlett et al, , 1982( Yarlett et al, , 1985.…”

Section: Introductionmentioning

confidence: 99%

“…In these organelles, pyruvate oxidation yields acetate, H2 and C 0 2 (Yarlett et al, 1981,1982). This organism is susceptible to oxygen when exposed to air, but it has a high affinity for O2 at low concentrations (Lloyd et al, 1982;Hillman et al, 1985b): the hydrogenosome has been implicated as a site of O2 consumption in both Tritrichomonas foetus (Cerkasov et al, 1978;Muller & Lindmark, 1978) and D . ruminantium (Yarlett et al, 1982).…”

Section: Introductionmentioning

confidence: 99%

“…This organism is susceptible to oxygen when exposed to air, but it has a high affinity for O2 at low concentrations (Lloyd et al, 1982;Hillman et al, 1985b): the hydrogenosome has been implicated as a site of O2 consumption in both Tritrichomonas foetus (Cerkasov et al, 1978;Muller & Lindmark, 1978) and D . ruminantium (Yarlett et al, 1982). H2 evolution is, however, markedly influenced by dissolved O2 ; 0, concentrations > 2.8 pmol l-l result in irreversible inactivation of the hydrogenase system (Yarlett et al, 1983;Hillman et al, 1985b).…”

Section: Introductionmentioning

confidence: 99%

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Influence of CO2 and low concentrations of O2 on fermentative metabolism of the rumen ciliate Dasytricha ruminantium

Ellis

McIntyre

Saleh

et al. 1991

Journal of General Microbiology

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The effects of ruminal concentrations of CO, and 0, on glucose-stimulated and endogenous fermentation of the rumen isotrichid ciliate Dusytrichu ruminantium were investigated. Principal metabolic products were lactic, butyric and acetic acids, H, and CO,. Traces of propionic acid were also detected; formic acid present in the incubation supernatants was found to be a fermentation product of the bacteria closely associated with this rumen ciliate. 13C NMR spectroscopy revealed alanine as a minor product of glucose fermentation by D. ruminantiurn. Glucose uptake and metabolite formation rates were influenced by the headspace gas composition during the protozoal incubations. The uptake of exogenously supplied D-ghCOSe was most rapid in the presence of 0, concentrations typical of those detected in sifu (i.e. 1-3 p~) .A typical ruminal gas composition (high CO,, low 0,) led to increased butyrate and acetate formation compared to results obtained using 0,-free N,. At a partial pressure of 66 kPa CO, in N,, increased cytosolic flux to butyrate was observed. At low 0, concentrations (1-3 p~ dissolved in the protozoal suspension) in the absence of CO,, increased acetate and CO, formation were observed and D. ruminantium utilized lactate in the absence of extracellular glucose. The presence of both 0, and CO, in the incubation headspaces resulted in partial inhibition of H2 production by D. ruminantiurn. Results suggest that at the 0, and CO, concentrations that prevail in situ, the contribution made by D. ruminantium to the formation of ruminal volatile fatty acids is greater than previously reported, as earlier measurements were made under anaerobic conditions.

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“…0001-6601 O 1991 SGM metabolites have been partially characterized ( Yarlett et al, 1981( Yarlett et al, , 1982( Yarlett et al, , 1985.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Influence of CO2 and low concentrations of O2 on fermentative metabolism of the rumen ciliate Dasytricha ruminantium

Ellis

McIntyre

Saleh

et al. 1991

Journal of General Microbiology

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“…The concentration of oxygen in the rumen is not constant and it falls to undetectable levels immediately after feeding. The physiological levels of this oxygen in the rumen, however, have pronounced effects on the ruminal microbial population and the microbes must be able to rapidly utilize oxygen and remove it from the environment (Lloyd et al 1982;Scott et al 1983). The ciliate protozoa account for approximately half of the total ruminal microbial biomass and occupy 10 percent of the total rumen volume (Jouany & Martin 1997).…”

Section: Introductionmentioning

confidence: 99%

Effects of protozoa on the antioxidant activity in the ruminal fluid and blood plasma of cattle

Gazi¹,

Yokota²,

Tanaka³

et al. 2007

Animal Science Journal

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The objective of this study was to investigate the antioxidant status in ruminal fluid and blood plasma among three faunated and two defaunated (protozoa‐free) cattle (average bodyweight of 225 kg), fed hay plus concentrate. The extra cellular antioxidant activity of the mixed protozoa and bacteria suspensions were also studied in vitro. The antioxidant activity was detected by means of the free radical scavenging ability. The activity (units/microbial nitrogen) of the protozoal suspension increased from 59 (0 h) to 318 (18 h), and decreased to 40 (24 h) during incubation. The activity of the bacterial suspension also increased from 111 (0 h) to 644 (18 h), and decreased to 533 (24 h). The antioxidant activity (units/mL, U/mL) in the ruminal fluid of faunated (ranging from 116 to 254) and defaunated (ranging from 66 to 110) cattle was increased after 2 h and decreased after 5 h of feeding, being significantly higher in the faunated cattle. The antioxidant activity of blood plasma (U/mL) ranged from 248 to 316 in the faunated and 121–170 in the defaunated cattle during 0–5 h after feeding, being significantly higher in the faunated cattle. Therefore, defaunation possibly causes a decrease in the antioxidant level in the ruminal fluid, and may impair the health and performance of ruminants through an oxidant–antioxidant imbalance.

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“…The hydrogenosome itself has a complex chain of flavin and iron-sulphur electron carriers (Ohnishi et al, 1980;Chapman et al, 1986) using either protons or oxygen as terminal electron acceptors. The production of H2 under anaerobic conditions is diminished in Trichomonas vaginalis when 0, is admitted (Lloyd & Kristensen, 1985), and the organism has an intense respiration and shows a high affinity for 0, (Lloyd et al, 1982(Lloyd et al, , 1987Yarlett et al, 1986).…”

Section: Introductionmentioning

confidence: 99%

The Effects of Oxygen on Fermentation in Tritrichomonas Foetus KV1 and its Variant 1MR-100 with Defective Hydrogenosomes

et al. 1987

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The effects of low concentrations of 0, on fermentation in the cattle parasite Tritrichomonas foetus KVl and its variant 1 MR-100 were compared using membrane inlet mass spectrometry to measure simultaneously and continuously ethanol, CO, and H,. In strain KVl glucosesupported H, and CO-, production were stimulated by O2 concentrations < 1.4 p~ but were inhibited at higher concentrations. Damped oscillatory responses in H, production indicated the operation of a feedback control system. Measurement of the 0,-dependence of 0, consumption rates confirmed the presence of a high-affinity terminal oxidase (apparent K , = 1.6 pi-0, at 37 "C) and substrate inhibition by 0, at > 8 ~M -O , .Successive periods of exposure to 0, resulted in decreased 0, scavenging capacity, as indicated by increasing apparent K , values for 0,. The variant strain 1 MR-100 which lacks pyruvate : ferredoxin oxidoreductase and hydrogenase showed quite different characteristics : H, production was not detectable, ethanol formation was inhibited by O2 (Ki = 1 p~) and 02-dependence of O2 consumption indicated that no high-affinity oxidase was present (apparent K , = 33 pw0,). Progressive increases in respiration rates on repeated exposure to low 0, concentrations indicated a capacity for adaptation to aerobiosis.

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Oxygen Affinities of the Hydrogenosome-containing Protozoa Tritrichomonas foetus and Dasytricha ruminantium, and Two Aerobic Protozoa, Determined by Bacterial Bioluminescence

Cited by 15 publications

References 19 publications

Influence of CO2 and low concentrations of O2 on fermentative metabolism of the rumen ciliate Dasytricha ruminantium

Influence of CO2 and low concentrations of O2 on fermentative metabolism of the rumen ciliate Dasytricha ruminantium

Effects of protozoa on the antioxidant activity in the ruminal fluid and blood plasma of cattle

The Effects of Oxygen on Fermentation in Tritrichomonas Foetus KV1 and its Variant 1MR-100 with Defective Hydrogenosomes

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