Showing papers on "Growth medium published in 1971"
TL;DR: Both the growth rate and the maximum population density of several normal, virus-transformed, and cancer cells were markedly pH-dependent; the optimum varied from pH 6.9 to 7.8.
Abstract: 1) Both the growth rate and the maximum population density of several normal, virus-transformed, and cancer cells were markedly pH-dependent; the optimum varied from pH 6.9 to 7.8. At the optimum pH, some diploid human cells attained population densities comparable to those of cancer or virus-transformed cells. Contact inhibition of growth is facilitated by repeated fluctuations of pH in nonphysiological ranges, and may not be an intrinsic and necessary attribute of diploid cells in culture. 2) At pH 8.3, at which there was little or no cellular multiplication, the protein content per cell increased 2- to 5-fold over a period of 10-16 days, and was slowly reversed to normal concentrations on restoration of pH to the optimal range. 3) Uridine uptake by contact-inhibited human cell cultures was stimulated by refeeding with salt solution, and to the same extent as by complete (serum-supplemented) growth medium; that immediate increase did not involve the reinitiation of cellular growth and multiplication. Contact inhibition was, however, reversed in 2-4 days by an appropriate increase in the serum concentration of the medium.
214 citations
TL;DR: By utilizing a shift down in temperature, biosynthesis of prodigiosin by washed cells could be separated from multiplication of bacteria, and measurements of viable count and of protein, plus other data, indicated that cellular multiplication did not occur in suspensions of washed cells during pigment formation.
Abstract: Maximal amounts of prodigiosin were synthesized in either minimal or complete medium after incubation of cultures at 27 C for 7 days. Biosynthesis of prodigiosin began earlier and the range of temperature for formation was greater in complete medium. No prodigiosin was formed in either medium when cultures were incubated at 38 C; however, after a shift to 27 C, pigmentation ensued, provided the period of incubation at 38 C was not longer than 36 hr for minimal medium or 48 hr for complete medium. Washed, nonpigmented cells grown in either medium at 38 C for 72 hr could synthesize prodigiosin when suspended in saline at 27 C when casein hydrolysate was added. These suspensions produced less prodigiosin at a slower rate than did cultures growing in casein hydrolysate at 27 C without prior incubation at 38 C. Optimal concentration of casein hydrolysate for pigment formation by suspensions was 0.4%; optimal temperature was 27 C. Anaerobic incubation, shift back to 38 C, killing cells by heating, or chloramphenicol (25 mug/ml) inhibited pigmentation. Suspensions of washed cells forming pigment reached pH 8.0 to 8.3 rapidly and maintained this pH throughout incubation for 7 days. Measurements of viable count and of protein, plus other data, indicated that cellular multiplication did not occur in suspensions of washed cells during pigment formation. By this procedure utilizing a shift down in temperature, biosynthesis of prodigiosin by washed cells could be separated from multiplication of bacteria.
97 citations
TL;DR: When compared at similar levels of water activity, glycerol was more inhibitory than sodium chloride to relatively salt-tolerant bacteria and less inhibitorythan salt to salt-sensitive species.
Abstract: When compared at similar levels of water activity, glycerol was more inhibitory than sodium chloride to relatively salt-tolerant bacteria and less inhibitory than salt to salt-sensitive species.
97 citations
TL;DR: Evidence is presented which indicates that the biosynthesis of phosphatidylcholine by the methylation pathway in growing cultures of Saccharomyces cerevisiae is repressed by the presence of choline, suggesting a regulatory effect similar to that demonstrated for the wild-type strain.
Abstract: Evidence is presented which indicates that the biosynthesis of phosphatidylcholine by the methylation pathway in growing cultures of Saccharomyces cerevisiae is repressed by the presence of choline in the growth medium. This result, obtained previously for glucose-grown cells, was also observed for lactate-grown cells, of which half of the phosphatidylcholine is mitochondrial. A respiration-deficient mutant of the parent wild-type strain has been studied, and its inability to form functional mitochondria cannot be due to an impaired methylation pathway, as it has been shown to incorporate 14C-CH3-methionine into all of the methylated glycerophosphatides. The incorporation rate is depressed by the inclusion of 1 mm choline in the growth medium, suggesting a regulatory effect similar to that demonstrated for the wild-type strain. The effects of choline on the glycerophospholipid composition of lactate and glucose-grown cells is presented. The repressive effects of the two related bases, mono- and dimethylethanolamine, were examined, and reduced levels of 14C-CH3-methionine incorporation were found for cells grown in the presence of these bases. The effect of choline on the methylation rates is reversible and glucosegrown cells regain the nonrepressed level of methylation activity in 60 to 80 min after removal of choline from the growth medium.
65 citations
TL;DR: A mutant (G11el) of Escherichia coli selected as being resistant to ampicillin and showing signs of an envelope defect was also found to be tolerant to colicins E2 and E3, suggesting that colicin tolerance often is a secondary consequence of a change in the cell envelope.
Abstract: A mutant (G11el) of Escherichia coli selected as being resistant to ampicillin and showing signs of an envelope defect was also found to be tolerant to colicins E2 and E3. The colicin tolerance of G11el could be partially repressed by Mg(2+) ions. Transition from tolerance to sensitivity and vice versa by shifting the concentration of Mg(2+) in the growth medium required several generations. This indicated that synthesis of new envelope material was needed for transition. Previous physiological results have indicated a change in the envelope lipopolysaccharide (LPS) of G11el. However, chemical analyses revealed no differences in carbohydrate composition between LPS from G11el and its parent strain G11al. Genetic experiments showed that the mutation in G11el is located at about 20 min on the E. coli K-12 chromosome. The mutation was dominant over wild type in partial diploids with the mutation located on the episome. Because colicin tolerance was the most striking phenotypic effect as a result of mutation in the actual locus, this gene will be named tolD until the exact gene product is known. Spheroplasts formed from G11al and G11el by ethylenediaminetetraacetate-lysozyme treatment did not adsorb colicin E2; however, penicillin spheroplasts of G11al and G11el were tolerant to colicin E2. Thus, colicin tolerance can be induced biochemically. It is suggested that colicin tolerance often is a secondary consequence of a change in the cell envelope.
36 citations
TL;DR: The data suggest that glutamine and cortisol act independently on the cells in regulating the level of the enzyme, and the presence of glutamine in the culture medium resulted in a fairly rapid rate of disappearance of the glutamine synthetase of previously induced cells.
Abstract: Glutamine synthetase activity of NCTC clone 929 mouse cells (strain L) was studied as a function of the prior nutritional experience of the cells. Small enzyme increases were recorded in response to either glutamine depletion or chronic serum supplementation of the growth medium. Somewhat greater increases resulted from the administration of cortisol or certain other steroids, particularly if the hormone treatment was combined with glutamine withdrawal. High concentrations of glutamate in the medium did not augment the glutamine synthetase content of the cells and even caused an apparent decrease in it. The presence of glutamine in the culture medium resulted in a fairly rapid rate of disappearance of the glutamine synthetase of previously induced cells. The data suggest that glutamine and cortisol act independently on the cells in regulating the level of the enzyme.
35 citations
TL;DR: It was confirmed that the rate of polymerization of at least the rRNA fraction in E. coli is virtually unaffected by the nature of the growth medium and therefore by bacterial growth rate.
Abstract: A study was made of the kinetics of labelling of the stable ribonucleic acids (rRNA+tRNA) and the unstable mRNA fraction in cultures of Escherichia coli M.R.E.600, inhibited by the addition of 0.1g of rifampicin/l. Labelling was carried out by adding either [2-14C]- or [5-3H]-uracil as an exogenous precursor of the cellular nucleic acids. From studies using DNA RNA hybridization, the kinetics of the synthesis and degradation of mRNA was followed in the inhibited cultures. Although a considerable proportion of the mRNA labelled in the presence of rifampicin decayed to non-hybridizable products, about 25% was stabilized beyond the point where protein synthesis had finally ceased. It therefore seems unwise to extrapolate the results of studies on mRNA stability in rifampicin-inhibited cultures to the situation existing in the rate of steady growth, where there appears to be little, if any, stable messenger. The kinetics of labelling of RNA in inhibited cultures indicated that the clapsed time from the addition of rifampicin to the point at which radioactivity no longer enters the total cellular ribonucleic acids is a measure of the time required to polymerize a molecule of rRNA. At 37°C, in culture grown in broth, glucose–salts or lactate salts media, exogenous [2-14C]uracil entered rifampicin-inhibited cells and was incorporated into RNA for 2 3min after the antibiotic was added. Taking this time as that required to polymerize a complete chain of 23S rRNA, the polymerization rate of this fraction in the three media was 25, 22 and 19 nucleotides added/s to the growing chains. Similar experiments in cultures previously inhibited by 0.2g of chloramphenicol/l showed virtually identical behaviour. This confirmed the work of Midgley & Gray (1971), who, by a different approach, showed that the polymerization rate of rRNA in steadily growing and chloramphenicol-inhibited cultures of E. coli at 37°C was essentially constant at about 22 nucleotides added/s. It was thus confirmed that the rate of polymerization of at least the rRNA fraction in E. coli is virtually unaffected by the nature of the growth medium and therefore by bacterial growth rate.
33 citations
TL;DR: Saccharomyces cerevisiae and Saccharomycles carlsbergensis were grown in batch culture with and without oxygen control and showed clear differences in the ability of either to divide or not to divide in solution.
Abstract: Saccharomyces cerevisiae and Saccharomyces carlsbergensis were grown in batch culture with and without oxygen control.
The concentrations of A-, B- and C-type cytochromes of both yeasts were dependent on the oxygen concentration during growth as well as on the initial glucose concentration of the growth medium. S. cerevisiae cytochromes were maximal after growth in low glucose and low oxygen; S. carlsbergensis cytochromes were maximal after growth in low glucose and high oxygen. Except when glucose was in very low concentration, its catabolism by S. carlsbergensis was directed predominantly towards ethanolic fermentation regardless of the oxygen concentration. Growth rate, total cell mass and yield were maximal, and anabolism was closely balanced with catabolism, when glucose and oxygen of S. carlsbergensis cultures were both high. Under these conditions neither catabolism, respiratory or ethanolic, nor glucose uptake were maximal.
23 citations
TL;DR: The level of cAMP-phosphodiesterase was much lower in cells of E. coli K-12 grown in glucose-containing medium than in glycerol- containing medium when in addition to glucose the growth medium contained also cAMP.
21 citations
TL;DR: It is shown, that using chloramphenicol treatment in the presence of lactose, followed by thermal induction of phage λ857, bacteria previously deinduced during two doubling periods appear heterogeneous, about half the population being poor in permease.
Abstract: Incubation of Escherichia coli with chloramphenicol causes metabolic and biosynthetic disturbances, the best known of which is the synthesis of RNA and formation of incomplete ribosomes (chloramphenicol particles). As a result of the unbalanced biosynthesis the bacteria transferred in a growth medium exhibit a prolonged lag of recovery and also a lag before development of and lysis by phage λ857 occurs. If lactose is the sole carbon source during incubation with chloramphenicol, the extent of these disturbaces is strongly dependent on the relative amount of β-galactoside permease.
15 citations
TL;DR: Since acquired tolerance was associated with an otherwise weakened culture, the occurrence of the tolerant cells to limit the efficacy of quaternary ammonium compounds in sanitation operations is highly unlikely.
Abstract: Acquired tolerance for a quaternary ammonium compound produced a tolerance for a similar compound. Tolerance was associated with the structure and the extent of adsorption of the compound. Morphological changes and resistance to disruption by pressure and by sonic treatment accompanied the development of tolerance. An otherwise weakened culture evolved with the acquisition of tolerance. The maximum obtainable viable population density of tolerant cells in growth medium was approximately 5% of that obtained in the parent culture. Tolerant cultures died off more rapidly in the original growth medium as well as when washed cell suspensions were stored at 5 C. Since acquired tolerance was associated with an otherwise weakened culture, the occurrence of the tolerant cells to limit the efficacy of quaternary ammonium compounds in sanitation operations is highly unlikely.
TL;DR: The finding that similar increases of Mg(2+) in the growth medium did not reverse the inhibition of B. cereus T is consistent with the conclusion that B. Cereus T, unlike E. coli, accumulates Mg (2+) to a constant concentration in its cell sap.
Abstract: Unlike Escherichia coli, Bacillus cereus T appears to accumulate Mg(2+) in its cell sap against a concentration gradient. Over a range of Mg(2+) in the growth medium from 5 x 10(-5) to 1.35 x 10(-2)m, the concentration of Mg(2+) in the cell sap of B. cereus T was maintained at about 6 x 10(-3)m, and ribosome-bound Mg(2+) and spermidine, as well as the spermidine concentration in the cell sap, appear to be unaffected by the concentration of Mg(2+) in the growth medium. Inhibition of growth of E. coli by streptomycin is progressively reversed by increasing the concentration of Mg(2+) in the growth medium above 5 mm. The finding that similar increases of Mg(2+) in the growth medium did not reverse the inhibition of B. cereus T is also consistent with the conclusion that B. cereus T, unlike E. coli, accumulates Mg(2+) to a constant concentration in its cell sap.
TL;DR: An an aerobic strain of corynebacteria resembling Corynebacterium anaerobicum was cultured in a fermentor at constant pH and no gelatinolytic, caseinolyic, nor aminopeptidase activity of the extracellular medium of cultures of this strain could be demonstrated.
Abstract: – An anaerobic strain of corynebacteria resembling Corynebacterium anaerobicum was cultured in a fermentor at constant pH. The growth medium was a glucose-proteose-peptone broth. Active hyaluronidase was liberated into the extra-cellular medium during growth as long as glucose was present in the medium. The pH optimum of the enzyme was between pH 5.0 and 6.2. The enzyme was stable between pH 5.0 and 9.4 and it was found to be heat labile. No gelatinolytic, caseinolytic, nor aminopeptidase activity of the extracellular medium of cultures of this strain could be demonstrated.
Patent•
03 May 1971
TL;DR: In this article, the authors describe a process for the production of YEAST UTILIZING as a grow-threshold medium for Yeast orGANISMS, a non-chlorinated, sterilized, and finetuned SEWAGE EFFLUENT in which the PH is in the range 5.0 to 8.0 and the OSMOTIC PRESSURE is in a range.05 M to 1.5 M NACL.
Abstract: THE SPECIFICATION DISCLOSES A PROCESS FOR THE PRODUCTION OF YEAST UTILIZING AS A GROWTH MEDIUM FOR YEAST ORGANISMS, A NON-CHLORINATED, STERILIZED AND FILTERED SEWAGE EFFLUENT IN WHICH THE PH IS IN THE RANGE 5.0 TO 8.0 AND THE OSMOTIC PRESSURE IS IN THE RANGE .05 M TO 1.5 M NACL. FERMENTATION OF YEAST SPECIES SACCHAROMYCES CEREVISIAE AND CANDIDA UNTILIS INDIVIDUALLY OR IN COMBINATON, AND OF YEAST SPECIES ENDOMYCOPSIS FIBULIGER IN COMBINATION WITH EITHER ONE OR BOTH OF THE AFORESAID SPECIES IS CONDUCTED UNDER AEROBIC CONDITIONS AT A TEMPERATURE IN THE RANGE OF 20* TO 35*C. FOR A PERIOD OF FROM 12 TO 30 HOURS. CENTRIFUGATION OF THE FERMENTED LIQUID SEPARATES OUT THE SOLID YEAST PARTICLES FROM LIQUID WASTE. REPETITIVE WASHING AND CENTRIFUGATION PROVIDES FOR PURIFICATION OF THE FINAL END PRODUCT.
TL;DR: A simple growth medium is reported, in which Bacillus megaterium forms heat-stable spores, heat-labile spores, or only vegetative cells by changing the carbon and nitrogen source.
Abstract: A simple growth medium is reported, in which Bacillus megaterium forms heat-stable spores, heat-labile spores, or only vegetative cells by changing the carbon and nitrogen source. Studies carried out in such media could be very useful in elucidating biochemical events which lead to bacterial sporulation.
TL;DR: Irrespective of aspartate concentration, a minimal concentration of biotin is so indispensable for normal growth that at lower biotin concentrations partial growth occurs followed by cell lysis, which is typical of cell wall lysis due to depletion of an amino acid essential for cell wall biosynthesis.
TL;DR: In this article, the effects of different concentrations of NaCl on the activities of acid phosphatase and PEP-phosphatase were investigated in the above mentioned plants.
Abstract: Plants ofSuaeda fructicosa were grown in sand culture with various combinations of excess copper, silicon and sodium. Effects of different concentrations of NaCl on the activities of acid phosphatase and PEP-phosphatase were investigated in the above mentioned plants. Plants which were given extra copper without NaCl showed very poor growth compared with control plants given a normal nutrient whereas plants given extra NaCl alone or with copper displayed luxuriant growth. Enzymes extracted from the plants given extra copper with normal nutrient levels showed stimulation in the activities of both the above mentioned enzymes. In plants supplied with extra sodium chloride the activity of acid phosphatase was inhibited and in that of PEP-phosphatase was stimulated. Sodium silicate in the growth medium eliminated both effects of extra sodium chloride.
TL;DR: Derepressed cells of Saccharomyces mellis treated in one of several different ways to either elute or inactivate the exocellular enzyme, acid phosphatase, showed a feedback control system and the synthesis of the extracellular enzyme does not seem to be controlled by a feedback mechanism but is produced at a maximal rate as long as the cells are growing.
Abstract: Derepressed cells of Saccharomyces mellis were treated in one of several different ways to either elute or inactivate the exocellular enzyme, acid phosphatase. The enzyme was either (i) eluted from resting cells with 0.5 m KCl plus 0.1% β-mercaptoethanol, (ii) eluted from exponential phase cells by growing the organism in derepressing media containing 0.5 m KCl, or (iii) inactivated on exponential phase cells by adding sufficient acid or base to growth media to destroy the enzyme but not enough to kill the cells. These treatments did not affect viability. Treated cells were transferred to fresh growth media or some other reaction mixture, and the kinetics of recovery of acid phosphatase activity was studied. In these reaction mixtures, enzyme was synthesized only by actively growing cells. Treated resting cells were indistinguishable from untreated, repressed resting cells in that the organism inoculated into complete growth medium remained in the lag phase for approximately 6 hr before both growth and enzyme synthesis began. Exponential phase derepressed cells treated by method (ii) or (iii) were transferred to fresh medium under conditions that allowed growth to continue. The cells immediately started to manufacture enzyme at a rate greater than normal until the steady-state level was reached, thus demonstrating a feedback control system. Exponential phase repressed cells were also transferred to fresh derepressing media under conditions which sustained growth. Though these cells began to grow immediately, there was a lag before acid phosphatase synthesis began followed by a lengthy inductive period. The length of the period of induction could be correlated with the polyphosphate content of the cells. As the supply of polyphosphate neared exhaustion, the rate of synthesis increased rapidly until it was greater than normal; this differential rate was sustained until the steady-state concentration was reached. When derepressed cells grow in a medium containing 0.5 m KCl, some acid phosphatase activity is found free in the culture fluid and some remains firmly attached to the cells despite the presence of the salt. The bound activity is subject to feedback control, but the steady-state level of this activity on the cells is only one-third that of the acid phosphatase on cells growing in nonsaline media. The extracellular phosphatase is produced at a rate that is several-fold greater than that of the exocellular enzyme in a nonsaline medium. The synthesis of the extracellular enzyme does not seem to be controlled by a feedback mechanism but is produced at a maximal rate as long as the cells are growing.
TL;DR: It was suggested that the antibiotic acted on the metabolic pathway of adenylic acid, adenosine and adenine, which exhibited the strongest competitive activity with the antibiotic.
Abstract: Five micrograms per milliliter of aristeromycin, a nucleoside antibiotic, completely inhibited the growth of Xanthomonas oryzae at all growing stages. When cells of Xanthomonas oryzae were treated with the antibiotic at the beginning of cultivation and transferred to a growth medium without antibiotic, the lag phase was prolonged without the change in the length of the log phase. Incubation of Xanthomonas oryzae with the antibiotic, reduces the viable cell count without affecting the optical density of the cell suspension. It was assumed that aristeromycin inhibited the growth of Xanthomonas oryzae by its bacteriocidal action. Ten to a hundred-fold mounts of either of adenosine, adenine, deoxyadenosine and inosine reversed the growth by aristeromycin. Complete reversal of the cell growth was not seen in the presence of these compounds because of their own growth inhibitory activity. Adenosine exhibited the strongest competitive activity with the antibiotic. It was suggested that the antibiotic acted on the metabolic pathway of adenylic acid, adenosine and adenine.
TL;DR: The results of the experiments reported here demonstrate that major changes in metabolism are taking place in mycelium which will ultimately differentiate into sporingmycelium, long before nutrient exhaustion has occurred in the growing medium.
Abstract: The concentrations of the intermediates of the EMP pathway and adenosine phosphates varied during the growth of Aspergillus niger as a function of the stage of the life-cycle and of the growth medium The concentrations of the EMP intermediates were considerably higher in extracts of mycelium from sporulation medium than from non-sporulation medium at the 24 h stage of development, well in advance of morphological evidence of sporulation At later stages of growth (48–72 h) the levels of the intermediates were relatively similar Throughout the growth cycles the concentrations of the adenosine phosphates were, in general, higher in extracts of mycelium from sporulation medium than from non-sporulation medium The results of the experiments reported here demonstrate that major changes in metabolism are taking place in mycelium which will ultimately differentiate into sporing mycelium, long before nutrient exhaustion has occurred in the growing medium