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J J Rowe

Publications and source records attributed to J J Rowe.

11 recordsLinked to original sources
PubMed1991

Nitrate transport and its regulation by O2 in Pseudomonas aeruginosa.

Pseudomonas aeruginosa is an obligate respirer which can utilize nitrate as a terminal electron acceptor under anaerobic conditions (denitrification). Immediate, transient regulation of nitrate respiration is mediated by oxygen through the inhibition of nitrate uptake. In order to gain an understanding of the bioenergetics of nitrate transport and its regulation by oxygen, the effects of various metabolic inhibitors on the uptake process and on oxygen regulation were investigated. Nitrate uptake was stimulated by the protonophores carbonyl cyanide m-chlorophenylhydrazone and 2,4-dinitrophenol, indicating that nitrate uptake is not strictly energized by, but may be affected by the proton motive force. Oxygen regulation of nitrate uptake might in part be through redox-sensitive thiol groups since N-ethylmaleimide at high concentrations decreased the rate of nitrate transport. Cells grown with tungstate (deficient in nitrate reductase activity) and azide-treated cells transported nitrate at significantly lower rates than untreated cells, indicating that physiological rates of nitrate transport are dependent on nitrate reduction. Furthermore, tungstate grown cells transported nitrate only in the presence of nitrite, lending support to the nitrate/nitrite antiport model for transport. Oxygen regulation of nitrate transport was relieved (10% that of typical anaerobic rates) by the cytochrome oxygen reductase inhibitors carbon monoxide and cyanide.

2,4-Dinitrophenol↗
PubMed1978

Denitrifying Pseudomonas aeruginosa: some parameters of growth and active transport.

Optimal cell yield of Pseudomonas aeruginosa grown under denitrifying conditions was obtained with 100 mM nitrate as the terminal electron acceptor, irrespective of the medium used. Nitrite as the terminal electron acceptor supported poor denitrifying growth when concentrations of less than 15 mM, but not higher, were used, apparently owing to toxicity exerted by nitrite. Nitrite accumulated in the medium during early exponential phase when nitrate was the terminal electron acceptor and then decreased to extinction before midexponential phase. The maximal rate of glucose and gluconate transport was supported by 1 mM nitrate or nitrite as the terminal electron acceptor under anaerobic conditions. The transport rate was greater with nitrate than with nitrite as the terminal electron acceptor, but the greatest transport rate was observed under aerobic conditions with oxygen as the terminal electron acceptor. When P. aeruginosa was inoculated into a denitrifying environment, nitrate reductase was detected after 3 h of incubation, nitrite reductase was detected after another 4 h of incubation, and maximal nitrate and nitrite reductase activities peaked together during midexponential phase. The latter coincided with maximal glucose transport activity.

Aerobiosis↗
PubMed1978

A cytochrome b-like pigment with a peak at 567 nm in Pseudomonas aeruginosa.

A cytochrome b - like pigment with an absorption peak at 567 nm was detected in Pseudomonas aeruginosa irrespective of whether the organism was grown aerobically or anaerobically under denitrifying conditions. This pigment has not been reported previously for P. aeruginosa but it has been detected in other denitrifying bacteria including closely related Pseudomonas species.

Aerobiosis↗
PubMed1977

The inhibitory effect of the artificial electron donor system, phenazine methosulfate-ascorbate, on bacterial transport mechanisms.

The artificial electron donor system, phenazine methosulfate (PMS)-ascorbate, inhibited active transort of solutes in Pseudomonas aeruginosa irrespective of whether the active transport systems were shock sensitive or shock resistant. N,N,N',N'-tetramethylphenylenediamine could be substituted for PMS but a higher concentration was required. PMS-ascorbate also inhibited active transport in several other bacterial species with the exception of Escherichia coli and of a nonpigmented strain of Serratia marcescens. PMS-ascorbate previously has been shown to energize active transport in isolated membrane vesicles, even those prepared from the same bacterial species in whose intact cells active transport was inhibited. The apparent Km of glucose active transport in untreated cells of P. aeruginosa was 40 micron while the Km of glucose transport in cells incubated with PMS-ascorbate was 25 mM, and PMS-ascorbate had no effect on efflux of accumulated glucose. These results strongly suggested that facilitated diffusion resulted upon exposure of the cells to PMS- ascorbate. Thus, PMS-ascorbate appeared to have an uncoupler-like effect on cells of P. aeruginosa. The experimental data also pointed out that there are fundamental differences between the response of intact cells and membrane vesicles to exogenous electron donors.

Ascorbic Acid↗
PubMed1977

Decrease in nitrate reductase activity in extracts of Trichoderma viride Incubated with chlorides.

Reduced nicotinamide adenine dinucleotide phosphate-dependent nitrate reductase activity in crude extracts of Trichoderma virde was significantly inhibited by physiological concentrations of ammonium chloride, sodium chloride, and potassium chloride, but not by ammonium or sodium sulfate. The chloride inhibition of nitrate reductase activity increased in a linear manner with chloride concentration.

Ammonium Chloride↗
PubMed1977

Studies on the modes of action of azaserine in Escherichia coli. Mechanism of resistance to azaserine.

Growth of wildtype Escherichia coli was inhibited by azaserine. There was an inverse relationship between the initial rate of uptake of phenylalanine and the azaserine concentration. Moderately azaserine-resistant mutants exhibited an initial rate that was similar to that of an aroP mutant, but highly azaserine-resistant mutants exhibited little, if any, uptake of phenylalanine. All of the azaserine-resistant organisms tested harboured a mutation in the aroP+ gene. However, resistance to the antibiotic was not due solely to this lesion.

Aspartic Acid↗
PubMed1976

Characteristics of Bacillus stearothermophilus mutants blocked in catabolic function.

With polyacrylamide disc gel electrophoresis and specific staining, it was demonstrated that one mutation involving the alcohol dehydrogenase of a double mutant of Bacillus stearothermophilus 1503 apparently prevented enzyme synthesis, and another lesion in the same organism resulted in synthesis of an inactive form of aconitase. Some properties of the double mutant and two fumarase mutants are discussed in relation to similar mutants derived from Bacillus subtilis.

Aconitate Hydratase↗
PubMed1975

Management of deer for experimental studies with foor-and-mouth disease virus.

Red, sika, fallow, roe and muntjac deer adapted to captivity in experimental units designed for working with foot-and-mouth disease. The red, sika and fallow deer readily accepted rolled oats and hay as their staple diet. This diet was replaced for the roe and muntjac deer with flaked maize, calf starter pellets and green browse. Etorphine/acepromazine ans xylazine were found to be suitable sedatives for detailed examination of the tongue and oral cavity of the various species of deer and gave adequate analgesia for the inoculation and collection of virus samples.

Abortion, Veterinary↗
PubMed1975

Development of defined and minimal media for the growth of Bacillus stearothermophilus.

Defined media, both solid and liquid, that support good growth of Bacillus stearothermophilus 1503 have been developed. Data are presented which indicate that manganese is required at relatively high concentrations for growth in a defined liquid medium. Phosphate concentrations higher than 5 times 10(-3) M have been shown to inhibit colony formation on solid media. Maximum viable counts of approximately 10(9) colony-forming units per ml were obtained in both the defined and minimal liquid media. Glucose, fructose, sucrose, glycerol, and starch support the growth of this obligate thermophile in the defined media, whereas citrate, alpha-ketoglutarate, succinate, fumarate, malate, acetate, and lactate do not. The described media have been utilized to isolate several amino acid-requiring mutants of B. stearothermophilus.

Agar↗