scholarly journals Can the pyruvate: ferredoxin oxidoreductase (PFOR) gene be used as an additional marker to discriminate among Blastocystis strains or subtypes?

2018 ◽  
Vol 11 (1) ◽  
Author(s):  
Patricia Alarcon-Valdes ◽  
Guiehdani Villalobos ◽  
Williams Arony Martinez-Flores ◽  
Eduardo Lopez-Escamilla ◽  
Nelly Raquel Gonzalez-Arenas ◽  
...  
1971 ◽  
Vol 246 (10) ◽  
pp. 3120-3125
Author(s):  
Kosaku Uyeda ◽  
Jesse C. Rabinowitz

1995 ◽  
Vol 41 (2) ◽  
pp. 198-201 ◽  
Author(s):  
James A. Daucher ◽  
Noel R. Krieg

Twelve strains representing 11 Campylobacter species were tested by two methods to see whether pyruvate:ferredoxin oxidoreductase, which occurs mainly in anaerobes, was also present in these oxygen-respiring microaerophiles. Crude extracts exhibited a pyruvate-dependent reduction of benzyl viologen and, to a lesser extent, metronidazole. Addition of Clostridium pasteurianum ferredoxin enhanced the metronidazole-reducing activity. All strains were inhibited by metronidazole, with minimal inhibitory concentrations ranging from 3 to 25 μg/mL. The results suggest that pyruvate: ferredoxin oxidoreductase is characteristic of the genus.Key words: Campylobacter, microaerophilic, metronidazole, pyruvate.


Parasitology ◽  
1993 ◽  
Vol 106 (1) ◽  
pp. 31-37 ◽  
Author(s):  
J. Tachezy ◽  
J. Kulda ◽  
E. Tomková

SUMMARYAerobic resistance of Trichomonas vaginalis to metronidazole was induced in vitro by anaerobic cultivation of drug-susceptible trichomonads with low concentrations of the drug (2–3 μg/ml) for 50 days. Minimal lethal concentrations (MLC) for metronidazole of the resistant derivatives were high in aerobic susceptibility assays (MLC = 216–261.5 μg/ml) but low in anaerobic assays (MLC = 4.2–6.3 μg/ml), surpassing MLC values of their parent strain approximately 50-fold and 3-fold under aerobiosis and anaerobiosis, respectively. Sensitivity to metronidazole under anaerobic conditions and activity of the hydrogenosomal enzyme pyruvate: ferredoxin oxidoreductase indicated that the resistance was of the aerobic type. Dependence of the resistance manifestation on O2 was further confirmed by susceptibility assays in vitro performed in defined gas mixtures of different oxygen content (1–20%). Five percent concentration of O2 proved to be the threshold required for resistance demonstration and the MLC values further increased with increasing O2 concentrations. The in vitro-induced resistance was also demonstrated in vivo by subcutaneous mouse assay. The dose of metronidazole needed to cure 50% of infected mice (DC50) was 223 mg/kg × 3 for resistant derivative MR-3a but 6.6 mg/kg × 3 only for its drug-susceptible parent strain. The metronidazole – resistant strains developed in this study correspond by their properties to drug-resistant T. vaginalis strains isolated from patients refractory to treatment, and promise to be a useful tool in the study of 5-nitroimidazole aerobic resistance.


1998 ◽  
Vol 44 (9) ◽  
pp. 819-824 ◽  
Author(s):  
Elizabeth MR Rees ◽  
David Lloyd ◽  
Alan G Williams

The effects of decreasing the concentration of CO2 and introducing up to 10% O2 into the headspace gases on the fermentative metabolism of the rumen fungi Neocallimastix patriciarum and Neocallimastix frontalis L2 were investigated. The relative proportion of metabolites produced by both fungi depended on the concentration of CO2 in the headspace. Under lowered CO2 levels, both fungi produced increased acetate, lactate, and H2, whereas the production of ethanol, formate, and (in the case of N. frontalis L2) succinate decreased. Lowered CO2 concentrations also decreased the rate of glucose utilization and cumulative gas production by both fungal isolates. In addition, decreased CO2 levels resulted in decreases in NAD(P)H ferredoxin oxidoreductase and hydrogenase activities, whereas malate dehydrogenase and pyruvate ferredoxin oxidoreductase activities were increased. Both N. patriciarum and N. frontalis L2 required at least 7% CO2 in the gas phase for growth. Both isolates also showed a degree of aerotolerance as they grew when exposed to 5% O2; they also grew in media lacking a reducing agent, providing that O2 was initially <1% of the total headspace concentration.Key words: rumen fungi, Neocallimastix, metabolism, carbon dioxide, oxygen.


2007 ◽  
Vol 159 (1) ◽  
pp. 9-18 ◽  
Author(s):  
F GARCZAREK ◽  
M DONG ◽  
D TYPKE ◽  
H WITKOWSKA ◽  
T HAZEN ◽  
...  

1987 ◽  
Vol 246 (2) ◽  
pp. 529-536 ◽  
Author(s):  
K Williams ◽  
P N Lowe ◽  
P F Leadlay

The pyruvate: ferredoxin oxidoreductase from the anaerobic protozoon Trichomonas vaginalis is an extrinsic protein bound to the hydrogenosomal membrane. It has been solubilized and purified to homogeneity, principally by salting-out chromatography on Sepharose 4B. Low recoveries of active enzyme were caused by inactivation by O2 and the irreversible loss of thiamin pyrophosphate. It is a dimeric enzyme of overall Mr 240,000 and subunit Mr 120,000. The enzyme contains, per mol of dimer, 7.3 +/- 0.3 mol of iron and 5.9 +/- 0.9 mol of acid-labile sulphur, suggesting the presence of two [4Fe-4S] centres, and 0.47 mol of thiamin pyrophosphate. The absorption spectrum of the enzyme is characteristic of a non-haem iron protein. The pyruvate: ferredoxin oxidoreductase from T. vaginalis is therefore broadly similar to the 2-oxo acid: ferredoxin (flavodoxin) oxidoreductases purified from bacterial sources, except that it is membrane-bound.


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