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At least 1,099 records · Page 61Linked to original sources

PubMed2005

pH effects on 10 Streptomyces spp. growth and sporulation depend on nutrients.

AIMS: Streptomycetes are regarded to prefer neutral to alkaline environmental pH, although they commonly occur at remarkably variable pH and nutritional conditions. Therefore, the dependence of 10 Streptomyces spp. pH tolerance on nutrients was determined. METHODS AND RESULTS: Ten environmental Streptomyces spp. were grown and sporulated between pH 4.0 and 11.5, at the interval of 1.5, on starch-casein-KNO(3), tryptone-yeast extract-glucose, glycerol-arginine and tryptone-soy agars, and three their modifications. On media with starch and casein; glucose, tryptone and yeast extract; tryptone and soy peptone; and glycerol-arginine and yeast extract strains grew over a broad pH range between 4.0-5.5 and 10.0-11.5. On glycerol-arginine and on medium with Na-propionate, NH(4)NO(3) and yeast extract, streptomycetes grew optimally at pH 7.0 and above. The high organic load enabled the growth over a wide pH range. The sporulation pH ranges followed those for growth. CONCLUSIONS: The high organic load enabled the growth over a wide pH range. The strain-specific differences in sporulation were greater than those caused by pH. The best medium for sporulation contained glucose and tryptone with minerals of glycerol-arginine agar at pH 5.5. SIGNIFICANCE AND IMPACT OF THE STUDY: The growth pH ranges, pH ranges for the optimal growth, and sporulation were strongly dependent on nutrients.

Agar↗

PubMed1976

Some factors influencing the haemolysis of Bordetella bronchiseptica.

Strain-dependent variations in the ability of Bordetella bronchiseptica to produce haemolysis on solid media exist. Haemolysis is strongest at an acid reaction and will not take place if the reaction is too alkaline. Peptone and glutamine inhibit haemolysis and favour growth. The vigorous growth rapidly produced an alkaline reaction which inhibits the haemolysis.

Amides↗

PubMed1967

The inhibition of induced motor activity in transplanted fundic pouches.

1. An increase in motor activity of transplanted fundic pouches can be produced repeatedly by an alkaline buffer solution in the duodenum.2. The response can be abolished by small doses of a cholecystokinin-pancreozymin extract.3. The secretagogues, olive oil and peptone will inhibit the response when introduced into the duodenum.4. Acetylcholine in the duodenum will also inhibit the effect.5. Hydrochloric acid will inhibit the motor activity produced by alkaline buffer in the duodenum and also resting activity of the pouches.

Acetylcholine↗

PubMed1986

The influence of intestinal infusion of fats on small intestinal motility and digesta transit in pigs.

The influence of duodenal and ileal infusion of nutrients on small intestinal transit of digesta, measured by the passage of phenol red marker, was studied in twelve pigs fitted with duodenal and ileal catheters, and a terminal ileal cannula. Changes in gastrointestinal motility were observed by electromyography and by use of an X-ray image intensifier in four of the pigs fitted additionally with nichrome wire electrodes in the gut wall and in seven pigs fitted only with a gastric catheter. Small intestinal transit time was unaffected by intestinal catheterization per se, or by duodenal or ileal infusion of glucose or peptone. It was reduced by duodenal infusion of fat or of some of the products of fat digestion including oleic acid and a monoglyceride containing unsaturated fatty acids (monoglyceride LS) but was not affected by infusion of glycerol, stearic acid or a monoglyceride containing saturated fatty acids (monoglyceride P). Ileal transit time was greatly reduced by ileal infusion of soya bean oil mixed with bile salts and lipase and by monoglyceride LS but not by soya bean oil alone. Total small intestinal transit time was reduced to a lesser degree by ileal infusion of soya bean oil mixed with bile salts and lipase and by monoglyceride LS and was unaffected by soya bean oil alone. The level of irregular spiking activity of the small intestine was greatly reduced by both duodenal and ileal infusion of fat, but rapidly propagated spike bursts were initiated from the point of infusion (identified radiologically as peristaltic rushes) many of which travelled right through to the ileo-caecal junction. It is concluded that intestinal infusion of fat accelerates small intestinal transit in pigs by induction of peristaltic rushes; that since the ileal transit times were more severely reduced than total small intestinal transit times by ileal infusion of fat the response is probably only seen over those areas of intestine in direct contract with the fat; and that the effect depends upon the presence of fat digestion products, i.e. the fatty acid and the monoglyceride, although probably only those containing unsaturated fatty acids.

Animals↗

PubMed1976

One-tube oxidation-fermentation methods: limitations posed by atypical fermentative reactions.

Atypical fermentation in the two-tube method of Hugh and Leifson (1953), whereby acid was produced in the sealed tube but not in the open tube, was determined to be the result of a preferential metabolism of peptone over the reactant carbohydrate. These atypical fermentations are only partially detected by one-tube oxidation-fermentation methods, and as such they constitute a source of limitation to the routine use of these abbreviated techniques for oxidative-fermentation determinations.

Aerobiosis↗

PubMed1980

Variability in gas production by Escherichia coli in enrichment media and its relationship to pH.

Variability in gas production in multiple subcultures of Escherichia coli was assessed in two selective enrichment media and in lactose peptone water. Considerable variability occurred with all media at 37 and 44 degrees C. Addition of buffer increased gas production and decreased variability. The relationships between pH, growth, and gas production were complex. In buffered media, viable counts increased by 269 x 10(6) to 382 x 10(6)/U of pH fall, whereas in unbuffered media, they increased by 9.45 x 10(6) to 30.37 x 10(6)/U of pH fall. In buffered and unbuffered media, pH fell as gas production rose. However, variability in gas production among individual subcultures was not associated with changes in pH.

Bacteriological Techniques↗

PubMed1986

Recovery and diversity of heterotrophic bacteria from chlorinated drinking waters.

Heterotrophic bacteria were enumerated from the Seattle drinking water catchment basins and distribution system. The highest bacterial recoveries were obtained by using a very dilute medium containing 0.01% peptone as the primary carbon source. Other factors favoring high recovery were the use of incubation temperatures close to that of the habitat and an extended incubation (28 days or longer provided the highest counts). Total bacterial counts were determined by using acridine orange staining. With one exception, all acridine orange counts in chlorinated samples were lower than those in prechlorinated reservoir water, indicating that chlorination often reduces the number of acridine orange-detectable bacteria. Source waters had higher diversity index values than did samples examined following chlorination and storage in reservoirs. Shannon index values based upon colony morphology were in excess of 4.0 for prechlorinated source waters, whereas the values for final chlorinated tap waters were lower than 2.9. It is not known whether the reduction in diversity was due solely to chlorination or in part to other factors in the water treatment and distribution system. Based upon the results of this investigation, we provide a list of recommendations for changes in the procedures used for the enumeration of heterotrophic bacteria from drinking waters.

Acridine Orange↗

PubMed1986

Selective medium for isolation of Fusarium species and dematiaceous hyphomycetes from cereals.

A selective medium containing 2 micrograms of dichloran per ml, 200 micrograms of chloramphenicol per ml, and 1.5% bacteriological peptone was developed for the isolation of Fusarium species and dematiaceous hyphomycetes from cereals. The medium, designated DCPA, was shown to select against species of Aspergillus, Penicillium, Cladosporium, and mucoraceous fungi. DCPA was evaluated for use as an enumeration medium and compared satisfactorily with dichloran-rose bengal-chloramphenicol agar when both media were tested with a range of cereal samples. Fusarium species and dematiaceous hyphomycetes produced well-formed colonies with good conidial production on DCPA, permitting rapid identification of such isolates on this medium.

Aniline Compounds↗

PubMed2002

Simple procedure for rapid identification of Vibrio cholerae from the aquatic environment.

Biochemical tests commonly used to screen for Vibrio cholerae in environmental samples were evaluated, and we found that a combination of alkaline peptone enrichment followed by streaking on thiosulfate citrate bile salts sucrose agar and testing for arginine dihydrolase activity and esculin hydrolysis was an effective rapid technique to screen for aquatic environmental V. cholerae. This technique provided 100% sensitivity and > or =70% specificity.

Animals↗

PubMed1965

EFFECTS OF CORN STEEP LIQUOR AND THIAMINE ON L-GLUTAMIC ACID FERMENTATION OF HYDROCARBONS.IV. UTILIZATION OF HYDROCARBONS BY MICROORGANISMS.

The effect of nutrients of natural source, such as corn steep liquor, peptone, and yeast extract, on the fermentative production of L-glutamic acid from hydrocarbons by a Corynebacterium was studied. Corn steep liquor and meat extract were found to be remarkably stimulatory to L-glutamic acid production; about 5 g per liter of L-glutamic acid were accumulated in a culture broth containing 3% n-paraffins, 0.01% corn steep liquor, and mineral salts. Among nutritional factors contained in corn steep liquor, biotin had very little effect on the accumulation of L-glutamic acid, but thiamine was highly stimulatory to L-glutamic acid production. The optimal concentration of thiamine for L-glutamic acid production was 3 to 5 mug per liter, and for cell growth, 50 mug per liter. L-Glutamic acid was accumulated in negligible quantity when the amount of thiamine in the culture broth was sufficient to support abundant growth of bacterial cells.

Biotin↗

PubMed1967

Rapid method for measuring extracellular water in yeast preparations.

A rapid procedure for the quantitative determination of extracellular water in bulk bakers' yeast was developed on the basis of the solute dilution principle. A reagent is prepared by synthesizing the diazonium ion of p-aminobenzoic acid and coupling it to peptone. This "azopeptone reagent" permits direct colorimetric measurement, which accounts for the rapidity and simplicity of the test. Potential errors due to osmotic effects are avoided by supplementing the reagent with saline and, more importantly, minimizing the duration of contact between reagent and cells. The new method has acceptable accuracy and precision, and may also be suitable for use with other microorganisms.

Colorimetry↗

PubMed1968

Detection and incidence of specific species of spoilage bacteria on fish. I. Methodology.

The ability of Pseudomonas putrefaciens to form H(2)S was found to serve as a singularly useful criterion of identity for this species and was used to directly enumerate the organism from haddock fillets by the use of pour plates of Peptone-Iron Agar. Subsurface colonies appear intensely black, whereas surface colonies are black or gray. A highly sensitive soft-agar-gelatin overlay technique has been found useful for directly determining the numbers of weakly and strongly proteolytic organisms from fish tissue.

Culture Media↗

PubMed1970

Rapid detection of sublethally impaired cells of Enterobacteriaceae in dried foods.

Samples of dried foods, feeds, and drugs were examined for Enterobacteriaceae by using buffered glucose-Brilliant Green-bile broth as the final enrichment medium and deep tubes of violet-red-bile-glucose-agar for confirmation. The pre-enrichment treatments used for the resuscitation of sublethally impaired cells were overnight incubation in lactose broth versus incubation for 1 to 6 hr at room temperature in shallow layers of tryptone soya peptone broth. The latter restoration treatment appeared to be significantly more productive.

Animal Feed↗

PubMed1971

Rapid method for the isolation of Listeria monocytogenes from experimentally infected mice.

Listeria monocytogenes was successfully isolated from experimentally infected mice by placing homogenized tissues in phosphate-buffered saline (PBS), trypsin, peptone, or pepsin followed by incubation at 37 C for 24 hr. A larger number of Listeria isolates were recovered from the trypsin or PBS splenic homogenate suspensions incubated at 37 C for 2 hr than from the other diluent suspensions. Holding infected tissues at 4 C for at least 3 months did not increase the efficiency of Listeria isolation. Listeria L-forms were not isolated from mice injected with the bacterial form. The in vitro viability of Listeria L-forms suspended in PBS or PBS splenic homogenate was greatly reduced when held at 4 C.

Agar↗

PubMed1971

Formation of aerial hyphae in Candida albicans.

Each of 22 isolates of Candida albicans was induced to produce aerial hyphae by culturing on a solid medium containing a peptone, acid-hydrolyzed casein, soluble starch, and agar in an atmosphere of 10% CO(2) at 37 C and room temperatures. Production of aerial hyphae is not diagnostic for C. albicans. Some of the other species of Candida may also produce such structures.

Agar↗

PubMed1971

Modified selective and differential isolation medium for Vibrio parahaemolyticus.

The semiselective salt-starch-agar formulation of Baross and Liston was modified as the result of a systematic study of the effect of each constituent on the growth of Vibrio parahaemolyticus and competitive species characteristic of the marine environment. The selection of nutrient constituents depended on an analysis of their effect on generation time. The addition of inhibitors depended on an analysis of minimal inhibitory concentrations. The modified formulation included: peptone, 2.0%; yeast extract, 0.2%; corn starch, 0.5%; NaCl, 3.0%; agar, 1.5% (pH 8.0). Penicillin at 2 to 5 units/ml increased selectivity without significantly inhibiting Vibrio in pure suspensions. Over 62% of the most sensitive strain (YM-K33) was recovered at a concentration of 5 units of penicillin per ml. The per cent recovery of V. parahaemolyticus from fish homogenate compared favorably with other selective formulations. At an initial concentration of 10(5) cells/ml, recovery varied with the strain used from 60 to 119%, whereas at 10(2) cells/ml the range was 36 to 94%. Applications of the medium for Vibrio quantification are discussed.

Agar↗

PubMed1971

Enzymatic production of L-citrulline by Pseudomonas putida.

To develop an efficient method for the production of l-citrulline, optimum conditions for the conversion of l-arginine to l-citrulline by microbial l-arginine deiminase and for production of the enzyme were studied. A number of micro-organisms were screened to test their ability to form and accumulate l-citrulline from l-arginine. Pseudomonas putida was selected as the best organism. With this organism, enzyme activity as high as 9.20 units per ml could be produced by a shaking culture at 30 C in a medium containing glucose, ammonium phosphate, l-arginine hydrochloride, yeast extract, peptone, and inorganic salts. Appropriate addition of a surface active agent to the reaction mixture was found to shorten the time required for the conversion. A large amount of l-arginine hydrochloride was converted stoichiometrically to l-citrulline in 62 hr at 37 C. Accumulated l-citrulline was readily isolated in pure form by ordinary procedures with ion-exchange resins. Yields of isolated l-citrulline of over 90.5% from l-arginine hydrochloride were easily attainable.

Air↗

PubMed1972

L-Asparaginase production by Streptomyces griseus.

Streptomyces griseus ATCC 10137 synthesizes about 1 IU of L-asparaginase/100 ml of a 4% peptone medium. The enzyme has a pH optimum of 8.5 which is comparable to that of the L-asparaginase derived from Escherichia coli which has antitumor properties.

Asparaginase↗