UTILIZATION OF SODIUM CASEINATE BY LACTIC STREPTOCOCCI AND ENTEROCOCCI

1956 ◽  
Vol 2 (6) ◽  
pp. 607-610 ◽  
Author(s):  
I. J. McDonald
Keyword(s):  
Nitrogen Source ◽  
Sodium Caseinate ◽  
Defined Medium ◽  
Starter Cultures ◽  
Sole Nitrogen Source ◽  
Chemically Defined Medium ◽  
Casein Hydrolyzate ◽  
Selection Of

The ability of lactic streptococci to utilize unhydrolyzed sodium caseinate as the nitrogen source in an otherwise chemically defined medium seems to be a strain rather than a species characteristic. This characteristic therefore appears to have little value as an aid in classification although it might have some importance in selection of starter cultures for cheese manufacture. None of the enterococci examined grew with unhydrolyzed sodium caseinate as the sole nitrogen source. However, Streptococcus liquefaciens and Streptococcus zymogenes appeared to utilize sodium caseinate when small amounts of casein hydrolyzate were added to the medium.

Utilization of chymotrypsin as a sole carbon and (or) nitrogen source by Escherichia coli

1992 ◽  
Vol 38 (4) ◽  
pp. 290-295 ◽  
Author(s):  
Arthur S. Brecher ◽  
Timothy A. Moehlman ◽  
William D. Hann
Keyword(s):  
Escherichia Coli ◽  
Carbon Source ◽  
Nitrogen Source ◽  
Degradation Products ◽  
Defined Medium ◽  
Host Protein ◽  
Mammalian Host ◽  
Sole Nitrogen Source ◽  
E Coli ◽  
Nitrogen Nutrients

α-Chymotrypsin serves as a sole carbon source, sole nitrogen source, and as sole carbon plus nitrogen source for wild-type Escherichia coli in a totally defined medium. Hence, a mammalian host for E. coli may supply the necessary carbon and nitrogen nutrients for the microorganism. Growth is most rapid when chymotrypsin is a sole nitrogen source,and least rapid with chymotrypsin as a carbon source. The approximate doubling times for E. coli utilizing chymotrypsin as a nitrogen source, carbon plus nitrogen source, and carbon source are 1.6, 4.6, and 11.3 h, respectively. The activity of the residual enzyme in the culture supernates falls off asymptotically over the course of time, as followed by cleavage of glutaryl-L-phenylalanine-p-nitroanilide. Chymotrypsin hydrolyzes succinyl-L-ala-L-ala-L-ala-p-nitroanilide, the elastase substrate, to some extent. Peptidases do not appear to be secreted that hydrolyze such model substrates as benzoyl-DL-arginine-p-nitroanilide, the tryptic and cathepsin B substrate, L-leucine-p-nitroanilide, the leucine aminopeptidase substrate, or L-lysine-p-nitroanilide, the aminopeptidase B substrate. Growth of E. coli is generally directly related to the loss of chymotryptic activity in the medium. Hence, autolysis of chymotrypsin, i.e., self-degradation, is an important factor for the availability of degradation products of the enzyme to the bacterium for growth purposes. Accordingly, the degradation of a host protein by autolysis presents an opportunity for E. coli to survive during periods of host nutritional crisis by utilization of the degradation peptides that are produced during autolysis. Key words: chymotrypsin, Escherichia coli, growth, nutrition, peptide source.

Nutritional characteristics of Megasphaera elsdenii

1978 ◽  
Vol 24 (8) ◽  
pp. 981-985 ◽  
Author(s):  
C.W. Forsberg
Keyword(s):  
Generation Time ◽  
Defined Medium ◽  
Energy Sources ◽  
Sole Nitrogen Source ◽  
Calcium Pantothenate ◽  
Chemically Defined Medium ◽  
Nutritional Characteristics ◽  
Megasphaera Elsdenii ◽  
Direct Inoculation ◽  
Sterile Medium

Megasphaera elsdenii B159 (formerly Peptostreptococcus elsdenii; Rogosa 1971) is able to grow in a chemically defined medium containing minerals, NH4+ as the sole nitrogen source, sulfate as the source of sulfur, acetate and glucose as the carbon and energy sources, and the vitamins biotin, pyridoxine, and calcium pantothenate. When lactate serves as the carbon source, with cysteine present as the reducing agent, acetate is not required. Valine and threonine appeared to be required although direct inoculation of unwashed cells into media lacking these amino acids permitted growth in their absence after an extended incubation period. Sulfur sources utilized included sulfate, sulfide, thiosulfate, cysteine, and glutathionine; methionine was utilized less readily. When glucose was autoclaved in the medium, the generation time of M. elsdenii was 170–200 min, but increased to more than 400 min when glucose was autoclaved separately and added to the cooled sterile medium. When fructose, which had been sterilized separately, was utilized as the carbon and energy source, the generation time was 200 min.

UTILIZATION OF CARBOHYDRATES BY ACTINOBACILLUS MALLEI

1966 ◽  
Vol 12 (4) ◽  
pp. 625-639 ◽  
Author(s):  
D. H. Evans
Keyword(s):  
Methylene Blue ◽  
Nitrogen Source ◽  
Ammonium Chloride ◽  
Carbon Sources ◽  
Defined Medium ◽  
Ammonium Citrate ◽  
Chemically Defined Medium ◽  
Negative Results ◽  
Proteose Peptone ◽  
Positive Results

Twenty-three substrains representing colonial variants of 11 strains of Actinabacillus mallei were examined for their ability to attack carbohydrates. Tests conducted in a basal liquid complex medium, containing yeast extract and proteose peptone No. 3 with bromcresol purple as indicator, showed that all strains tested produced acid from arabinose, glucose, fructose, galactose, mannose, and trehalose, while five substrains gave positive results with lactose, one with sucrose, and two with maltose. Eosin methylene blue agar of the same basal composition gave positive results for most of the strains grown on arabinose, glucose, fructose, galactose, mannose, and trehalose, and negative results for all strains grown on xylose, lactose, sucrose, and maltose. In a chemically defined medium containing ammonium chloride as nitrogen source and bromcresol purple as indicator, acid was produced by eight substrains of five of these strains from glucose, galactose, mannose, and trehalose, and by several strains from fructose and sucrose. The ability of these five selected strains to utilize carbohydrates as sole carbon sources for growth was tested in a chemically defined medium containing ammonium citrate as nitrogen source. All strains were able to grow on glucose, galactose, mannose, and trehalose, and most were able to grow on fructose. Arabinose, xylose, lactose, sucrose, and maltose did not support the growth of any of the strains tested.

Nitrogen source regulates expression of alanine dehydrogenase isoenzymes in Streptomyces avermitilis in a chemically defined medium

1997 ◽  
Vol 43 (2) ◽  
pp. 189-193 ◽  
Author(s):  
Jan Novák ◽  
Jan Kopecký ◽  
Zdenko Vaněk
Keyword(s):  
Nitrogen Source ◽  
Ammonium Sulfate ◽  
Alanine Aminotransferase ◽  
Specific Activity ◽  
Defined Medium ◽  
Streptomyces Avermitilis ◽  
Chemically Defined Medium ◽  
Ammonium Ions ◽  
Alanine Dehydrogenase ◽  
Dehydrogenase Reaction

Ammonium ions and alanine influence production of the macrolide avermectin in Streptomyces avermitilis. L-Alanine dehydrogenase and alanine aminotransferase are the primary enzymes responsible for regulating the intracellular concentration of alanine and also of ammonium ions. In cultures of S. avermitilis in a chemically defined medium with ammonia or L-alanine as the only nitrogen source, specific activities of both enzymes increased during growth. The alanine dehydrogenase specific activity increased more than 86-fold after the culture was supplemented with 0.2% L-alanine and 5-fold after addition of 0.5% ammonium sulfate, whereas alanine aminotransferase specific activity increased 3- to 4-fold with either substrate. Five isoenzymes of alanine dehydrogenase were detected histochemically in S. avermitilis after native gel electrophoresis. Isoenzyme 1 was induced by alanine and temporarily repressed by high concentrations of ammonium sulfate. The presence of isoenzyme 1 was also related to changes in the kinetic properties of the alanine dehydrogenase reaction measured in crude desalted extracts. A nonlinear double-reciprocal plot was obtained in initial velocity studies using L-alanine as a substrate in the sample induced with L-alanine. The nonlinearity was caused by both substrate inhibition and allosteric regulation (positive cooperativity) by L-alanine. In contrast, the sample induced by ammonium sulfate showed a linear double-reciprocal plot.Key words: isoenzymes, L-alanine dehydrogenase, Streptomyces avermitilis, avermectin.

scholarly journals The Growth Of Rhizobium in Synthetic Media

1961 ◽  
Vol 14 (3) ◽  
pp. 349 ◽  
Author(s):  
FJ Bergersen
Keyword(s):  
Amino Acids ◽  
Nitrogen Source ◽  
Exponential Growth ◽  
Defined Medium ◽  
Complete Medium ◽  
Good Growth ◽  
Chemically Defined Medium ◽  
Sodium Glutamate ◽  
Synthetic Media

A chemically defined medium for the growth of Rhizobium is described in which populations of up to 5 x 109 cells/ml were obtained. For the six strains of bacteria studied the complete medium supported exponential growth for two to five generations. The concentrations of biotin giving best growth varied ith strain between 125 and 250 f'g/l when the nitrogen source was sodium glutamate. NHt, NOs, and other amino acids, singly or in combination, did not upport as good growth as did sodium glutamate.

Selection of kidney cell types in primary glomerular explant outgrowths by in vitro culture conditions

1986 ◽  
Vol 84 (1) ◽  
pp. 69-92
Author(s):  
T.D. Oberley ◽  
A.H. Yang ◽  
J. Gould-Kostka
Keyword(s):  
Epithelial Cell ◽  
Cell Types ◽  
Defined Medium ◽  
Culture Conditions ◽  
Chemically Defined Medium ◽  
Cell Type ◽  
Epithelial Cell Type ◽  
Tubular Cells ◽  
Selection Of

Adult guinea pig glomeruli were grown in vitro either in serum or in a chemically defined medium. Glomeruli were plated either directly into plastic flasks or into plastic flasks that had been coated with the extracellular matrix produced by the PF-HR-9 mouse teratocarcinoma endodermal cell line. Both the composition of the medium and the nature of the culture substrate affected whole glomerular attachment and the type of cells produced in culture. Quantitative studies demonstrated selection of cell types by different culture conditions. Three colony types, each composed of distinctive cell types, could be identified by morphological features. The cells constituting two of these colony types were epithelial in nature, but they were identified as different epithelial types by both histochemical and ultrastructural criteria. Previous studies suggested that one epithelial cell type was derived from the glomerular visceral epithelial cell. This study demonstrates that this cell type could be selectively grown in defined medium on plastic. A second cell type showed several features of renal tubular epithelial cells, including histochemical staining for catalase, cell surface microvilli and cilia, and formation of hemicysts and structures that resembled tubules after prolonged periods in culture. To demonstrate that the ‘glomerulus-derived’ tubular cells were indeed tubular epithelium, we isolated purified renal cortical tubules (greater than 99% pure) and cultured them on the HR-9 matrix in a serum-free chemically defined medium. The resultant outgrowths had morphological properties identical to those of the glomerulus-derived tubular cells. It seems likely that small tubular fragments attached to a minority of the glomeruli are the source of these glomerulus-derived tubular cells. Neither epithelial cell type could be subcultured on plastic, but both could be passaged on the HR-9 matrix. A third cell type, the spindle-shaped cell, was easily propagated on both plastic and the HR-9 matrix. The origin of this cell type is not clear. Our results demonstrate the important effect of culture conditions on the selection, growth and differentiation of kidney cell types in vitro.

Selection of a chemically defined medium for culturing adult newt forelimb regenerates

In Vitro ◽  
1979 ◽  
Vol 15 (6) ◽  
pp. 409-414 ◽  
Author(s):  
M. E. Conn ◽  
G. E. Dearlove ◽  
M. H. Dresden
Keyword(s):  
Defined Medium ◽  
Chemically Defined Medium ◽  
Adult Newt ◽  
Selection Of

scholarly journals Glutathione Protects Lactococcus lactis against Oxidative Stress

2003 ◽  
Vol 69 (10) ◽  
pp. 5739-5745 ◽  
Author(s):  
Yin Li ◽  
Jeroen Hugenholtz ◽  
Tjakko Abee ◽  
Douwe Molenaar
Keyword(s):  
Glutathione Peroxidase ◽  
Stationary Phase ◽  
Glutathione Reductase ◽  
Lactococcus Lactis ◽  
Storage Conditions ◽  
Defined Medium ◽  
Starter Cultures ◽  
Oxidized Glutathione ◽  
Chemically Defined Medium ◽  
Different Strains

ABSTRACT Glutathione was found in several dairy Lactococcus lactis strains grown in M17 medium. None of these strains was able to synthesize glutathione. In chemically defined medium, L. lactis subsp. cremoris strain SK11 was able to accumulate up to ∼60 mM glutathione when this compound was added to the medium. Stationary-phase cells of strain SK11 grown in chemically defined medium supplemented with glutathione showed significantly increased resistance (up to fivefold increased resistance) to treatment with H2O2 compared to the resistance of cells without intracellular glutathione. The resistance to H2O2 treatment was found to be dependent on the accumulation of glutathione in 16 strains of L. lactis tested. We propose that by taking up glutathione, L. lactis might activate a glutathione-glutathione peroxidase-glutathione reductase system in stationary-phase cells, which catalyzes the reduction of H2O2. Glutathione reductase, which reduces oxidized glutathione, was detectable in most strains of L. lactis, but the activities of different strains were very variable. In general, the glutathione reductase activities of L. lactis subsp. lactis are higher than those of L. lactis subsp. cremoris, and the activities were much higher when strains were grown aerobically. In addition, glutathione peroxidase is detectable in strain SK11, and the level was fivefold greater when the organism was grown aerobically than when the organism was grown anaerobically. Therefore, the presence of glutathione in L. lactis could result in greater stability under storage conditions and quicker growth upon inoculation, two important attributes of successful starter cultures.

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