Absence of storage products in cultures of Pseudomonas aeruginosa grown with excess carbon or nitrogen

1968 ◽  
Vol 14 (6) ◽  
pp. 627-631 ◽  
Author(s):  
R. M. MacKelvie ◽  
J. J. R. Campbell ◽  
Audrey F. Gronlund
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Nitrogen Source ◽  
Cell Suspensions ◽  
Excess Carbon ◽  
Washed Cell ◽  
Keto Acids ◽  
Limiting Nutrient ◽  
Storage Products ◽  
Production Of Ammonia

Pseudomonas aeruginosa failed to accumulate carbohydrate, lipid, including poly-β-hydroxybutyrate, or polyphosphate when grown under conditions normally favorable for the deposition of these reserve materials. Washed cell suspensions prepared from cultures grown under conditions of limiting nitrogen, limiting carbon, or excess of both exhibited immediate and linear production of ammonia when starved. When glucose-U-14C was added to a 24-h-culture, growing in a nitrogen-limited medium, the radioactivity was largely recovered in keto acids which accumulated in the growth supernatant. Exhaustion of the limiting nutrient during growth resulted in the degradation of ribosomes regardless of whether the nutrient was the carbon or nitrogen source.

Effects of sulfide and acetylene on nitrous oxide reduction by soil and by Pseudomonas aeruginosa

1979 ◽  
Vol 25 (10) ◽  
pp. 1133-1138 ◽  
Author(s):  
Tat-Yee Tam ◽  
Roger Knowles
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Nitrous Oxide ◽  
Sodium Sulfide ◽  
Sodium Thiosulfate ◽  
Cell Suspensions ◽  
Inhibition Assay ◽  
Sterile Soil ◽  
Washed Cell ◽  
Complete Reduction ◽  
Nitrous Oxide Reduction

The production and reduction of nitrous oxide (N2O) after the addition of N2O, nitrite (NO2−), or nitrate (NO3−) was studied in non-sterile soil, in sterilized soil inoculated with Pseudomonas aeruginosa, and in washed cell suspensions of this organism. Sodium sulfide (8 μmol S2− mL−1 or g−1) inhibited N2O reduction markedly in cell suspensions and also in soil, an effect which may cause sulfidic habitats to act as sources of N2O. Sodium thiosulfate (up to 64 μmol S2O32− g−1) showed no such effect. Acetylene (0.02 atm C2H2) completely inhibited the reduction of N2O by soil, but the combination of C2H2 with 8 μmol S2− g−1 permitted the complete reduction of 2 μmol added N2O g−1 within 3 days under the most favourable conditions. Under the same conditions, 8 μmol S2O32− g−1 permitted complete reduction of the N2O within 6 days. The rate of such reduction of N2O was decreased, but not inhibited completely, by raising the C2H2 concentration to 0.11 atm. The data have important implications for the effectiveness of the C2H2 inhibition assay of denitrification in highly anaerobic environments.

Production of Rhamnolipid Biosurfactant from Fed Batch Culture by Pseudomonas aeruginosa using Multiple Substrates

2020 ◽  
Vol 16 (6) ◽  
pp. 928-933
Author(s):  
Jujjavarapu S. Eswari
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Batch Process ◽  
Time Interval ◽  
Fed Batch ◽  
Multiple Substrates ◽  
Surface Active Agents ◽  
Limiting Nutrients ◽  
Limiting Nutrient ◽  
Surface Active ◽  
Rhamnolipid Biosurfactant

Objective: Biosurfactants are the surface active agents which are used for the reduction of surface and interfacial tensions of liquids. Rhamnolipids are the surfactants produced by Pseudomonas aeruginosa. It requires minimum nutrition for its growth as it can also grow in distilled water. The rhamnolipids produced by Pseudomonas aeruginosa are extra-cellular glycolipids consisting of L-rhamnose and 3-hydroxyalkanoic acid. Methods: The fed-batch method for the rhamnolipid production is considered in this study to know the influence of the carbon, nitrogen, phosphorous substrates as growth-limiting nutrients. Pulse feeding is employed for limiting nutrient addition at particular time interval to obtain maximum rhamnolipid formation from Pseudomonas aeruginosa compared with the batch process. Results: Out of 3 fed batch strategies constant glucose fed batch strategy shows best and gave maximum rhamnolipid concentration of 0.134 g/l.

A NEW NON-PROTEIN NITROGEN SOURCE FOR RUMINANTS

1969 ◽  
Vol 49 (2) ◽  
pp. 135-141 ◽  
Author(s):  
L. P. Milligan ◽  
A. R. Robblee ◽  
J. C. Wood ◽  
W. C. Kay ◽  
S. K. Chakrabartty
Keyword(s):  
Nitrogen Source ◽  
Dietary Supplement ◽  
Nitrogen Retention ◽  
Feeding Trial ◽  
Short Term ◽  
Protein Nitrogen ◽  
Rumen Microorganisms ◽  
Production Of Ammonia

The preparation of a polymer of urea and furfural containing 23.2% nitrogen is described. This product was converted by rumen microorganisms in vitro to ammonia at a rate approximately one-seventh that of conversion of urea to ammonia. Use of the polymer as a dietary supplement in a feeding trial with lambs improved nitrogen retention over that of unsupplemented controls by 3.45 g of nitrogen retained per day, while an isonitrogenous quantity of supplemental urea improved nitrogen retention by 0.51 g of nitrogen retained per day. The blood urea pattern, throughout the day, of lambs adapted to control, urea-supplemented and urea–furfural polymer-supplemented rations indicated a slow, prolonged production of ammonia from the latter supplement and very rapid, short-term degradation of urea in vivo.

Reversal of succinate-mediated catabolite repression of alkylsulfatase in Pseudomonas aeruginosa by 2,4-dinitrophenol and by sodium malonate

1978 ◽  
Vol 24 (12) ◽  
pp. 1567-1573 ◽  
Author(s):  
J. W. Fitzgerald ◽  
L. C. Kight-Olliff ◽  
G. J. Stewart ◽  
N. F. Beauchamp
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Induction Period ◽  
Sodium Succinate ◽  
Cell Suspensions ◽  
Atp Content ◽  
Succinate Oxidation ◽  
Sodium Malonate ◽  
Atp Levels ◽  
Sodium Malate ◽  
Stimulation Of

The Kreb's cycle intermediates and related metabolites (e.g., acetate) repressed the induced synthesis of alkylsulfatase in resting cell suspensions of Pseudomonas aeruginosa. At concentrations which caused substantial repression, sodium succinate as well as sodium malate, fumarate, and α-ketoglutarate were oxidized to yield consistently high levels of ATP throughout the induction period. Sodium oxalacetate which was markedly less effective as a metabolite repressor generated high ATP levels only during the first 2 h of the induction period. The addition of 2,4-dinitrophenol or sodium malonate to cell suspensions containing the inducer (sodium hexan-1-yl sulfate) and succinate overcame repression of alkylsulfatase formation and resulted in a reduction in the ATP content to levels found in cells exposed only to inducer. An apparent stimulation of alkylsulfatase induction occurred in the absence of succinate when cells were incubated with 2,4-dinitrophenol and inducer. In this case, the ATP content of the cell suspension fell to levels substantially below those occurring as a result of inducer catabolism. Collectively, these data suggest that the effectiveness of succinate as a metabolite repressor is related to the ATP levels generated as a consequence of succinate oxidation.

scholarly journals Production and characterization of rhamnolipids from Pseudomonas aeruginosa san ai

2012 ◽  
Vol 77 (1) ◽  
pp. 27-42 ◽  
Author(s):  
Milena Rikalovic ◽  
Gordana Gojgic-Cvijovic ◽  
Miroslav Vrvic ◽  
Ivanka Karadzic
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Response Surface Methodology ◽  
Nitrogen Source ◽  
Testing Effect ◽  
Carbon And Nitrogen ◽  
Rhamnolipid Production ◽  
Proteose Peptone ◽  
Isolated Compound ◽  
Rhamnolipid Biosurfactant

Production and characterization of rhamnolipid biosurfactant obtained by strain Pseudomonas aeruginosa san ai was investigated. With regard to carbon and nitrogen source several media were tested to enhance production of rhamnolipids. Phosphate-limited proteose peptone-ammonium salt (PPAS) medium supplemented with sun flower oil as a source of carbon and mineral ammonium chloride and peptone as a nitrogen source greatly improved rhamnolipid production, from 0.15 on basic PPAS (C/N ratio 4.0), to 3 g L-1, on optimized PPAS medium (C/N ratio 7.7). Response surface methodology analysis was used for testing effect of three factors: temperature, concentration of carbon and nitrogen source (w/w), in optimized PPAS medium on rhamnolipid production. Isolated rhamnolipids were characterized by IR and ESI-MS. IR spectra confirmed that isolated compound corresponds to rhamnolipid structure, whereas MS indicated that isolated preparation is a mixture of mono-rhamno-mono-lipidic, mono-rhamno-di-lipidic- and dirhamno- di-lipidic congeners.

scholarly journals Effect of subinhibitory concentrations of benzalkonium chloride on the competitiveness of Pseudomonas aeruginosa grown in continuous culture

Microbiology ◽  
2010 ◽  
Vol 156 (1) ◽  
pp. 30-38 ◽  
Author(s):  
Paul H. Mc Cay ◽  
Alain A. Ocampo-Sosa ◽  
Gerard T. A. Fleming
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Continuous Culture ◽  
Benzalkonium Chloride ◽  
Efflux Pump ◽  
Fold Increase ◽  
Original Strain ◽  
Limiting Nutrient ◽  
Continuous Culture System ◽  
Subinhibitory Concentrations ◽  
Limited Culture

This study investigates the link between adaptation to biocides and antibiotics in Pseudomonas aeruginosa. An enrichment continuous culture of P. aeruginosa NCIMB 10421 (MIC 25 mg BKC l−1) was operated (D=0.04 h−1, 792 h) with added benzalkonium chloride (BKC). A derivative, PA-29 (696 h), demonstrated a >12-fold decrease in sensitivity to the biocide (MIC >350 mg BKC l−1). The variant demonstrated a 256-fold increase in resistance to ciprofloxacin, with a mutation in the gyrA gene (Thr-83→Ile). Similarly, culturing of the original strain in a continuous-culture system with ciprofloxacin selection pressure led to the evolution of BKC-adapted populations (MIC 100 mg BKC l−1). Efflux pump activity predominantly contributed to the developed phenotype of PA-29. An amino acid substitution (Val-51→Ala) in nfxB, the Mex efflux system regulator gene, was observed for PA-29. Overexpression of both MexAB-OprM and MexCD-OprJ was recorded for PA-29. Similarly, mexR, a repressor of the Mex system, was downregulated. Competition studies were carried out in continuous culture between PA-29 and the original strain (in the presence of subinhibitory concentrations of BKC). The outcome of competition was influenced by the concentration of biocide used and the nature of limiting nutrient. The inclusion of 1 mg BKC l−1 in the medium feed was sufficient to select (S=0.011) for the BKC-adapted strain in magnesium-limited culture. Conversely, the presence of 10 mg BKC l−1 in the medium supply was insufficient to select for the same organism (S=−0.017) in the glucose-limited culture. These results indicate the importance of environmental conditions on selection and maintenance of biocide adaptation.

scholarly journals The synthesis of indole by washed cell suspensions of Escherichia coli

1956 ◽  
Vol 64 (1) ◽  
pp. 132-137 ◽  
Author(s):  
F. Gibson ◽  
Marjorie J. Jones ◽  
H. Teltscher
Keyword(s):  
Escherichia Coli ◽  
Cell Suspensions ◽  
Washed Cell

scholarly journals Effect of Linoleic Acid Concentration on Conjugated Linoleic Acid Production by Butyrivibrio fibrisolvensA38

2000 ◽  
Vol 66 (12) ◽  
pp. 5226-5230 ◽  
Author(s):  
Young Jun Kim ◽  
Rui Hai Liu ◽  
Daniel R. Bond ◽  
James B. Russell
Keyword(s):  
Linoleic Acid ◽  
Conjugated Linoleic Acid ◽  
Cell Density ◽  
Cell Suspensions ◽  
Bacterial Inactivation ◽  
Butyrivibrio Fibrisolvens ◽  
Washed Cell ◽  
Initial Cell ◽  
Normal Enzyme ◽  
Linoleic Acid Concentration

ABSTRACT Butyrivibrio fibrisolvens A38 inocula were inhibited by as little as 15 μM linoleic acid (LA), but growing cultures tolerated 10-fold more LA before growth was inhibited. Growing cultures did not produce significant amounts of cis-9, trans-11 conjugated linoleic acid (CLA) until the LA concentration was high enough to inhibit biohydrogenation, growth was inhibited, and lysis was enhanced. Washed-cell suspensions that were incubated anaerobically with 350 μM LA converted most of the LA to hydrogenated products, and little CLA was detected. When the washed-cell suspensions were incubated aerobically, biohydrogenation was inhibited, CLA production was at least twofold greater, and CLA persisted. The LA isomerase reaction was very rapid, but the LA isomerase did not recycle like a normal enzyme to catalyze more substrate. Cells that were preincubated with CLA lost their ability to produce more CLA from LA, and the CLA accumulation was directly proportional (r 2= 0.98) to the initial cell density. Growing cells were as sensitive to CLA as LA, the LA isomerase and reductases of biohydrogenation were linked, and free CLA was not released. Because growing cultures ofB. fibrisolvens A38 did not produce significant amounts of CLA until the LA concentration was high, biohydrogenation was arrested, and the cell density had declined, the flow of CLA from the rumen may be due to LA-dependent bacterial inactivation, death, or lysis.

Stimulation by pH of cell cycle initiation in the yeast Candida utilis

1981 ◽  
Vol 59 (11) ◽  
pp. 2043-2048 ◽  
Author(s):  
K. Chandapillai Thomas
Keyword(s):  
Cell Cycle ◽  
Nitrogen Source ◽  
Growth Medium ◽  
Respiratory Quotient ◽  
Doubling Time ◽  
Candida Utilis ◽  
Cellular Processes ◽  
Ph Shift ◽  
Bud Emergence ◽  
Limiting Nutrient

The effect of shifting pH of the growth medium on cell cycle initiation by the yeast Candida utilis was studied. The yeast was grown by the phased method of cultivation with nitrogen source (ammonium) in growth limiting concentrations and with a phasing period (imposed doubling time) of 6 h. The pH of the culture during the phased growth was maintained between 2.0 and 2.1. The rate of cell cycle initiation as determined by the rate of bud emergence was 24% per hour. If the pH of the culture was shifted to 6.0 at the beginning of the phasing period and maintained at that level for the rest of the phasing period the rate of bud emergence increased to 50% per hour. The increased rate of bud emergence was accompanied by a fast uptake of oxygen and the growth-limiting nutrient and by a reduction in the respiratory quotient. The results suggest that the pH shift accelerated cellular processes necessary for cell cycle initiation.

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