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Query: UMLS:C0847097 (acidity)
 15,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Streptomyces populations inhabiting five acidic forest soils were examined. It was found that lowering the pH of a medium selective for streptomycetes (starch-casein agar) to the pH of the particular soil horizon being plated influenced both the total numbers and types of streptomycetes that were isolated from the soils examined in this study. On the acidified medium both the numbers of streptomycetes and the percentage of total bacteria on the plates represented by streptomycetes increased (as compared with the same medium with a pH of 7.2). These differences were greatest on the isolations from the most acid soils. The largest concentrations of streptomycetes were found in the surface horizon (0 to 15 cm) and the litter layer immediately over the surface mineral horizon. Acidity tolerance tests demonstrated that random samplings of isolates contained acidophilic, neutrophilic, and acidoduric strains, with the largest numbers of acidophiles being found on the acidified media from the most acid soils. There were no differences between overall utilization of selected carbohydrates among the isolates taken from either the neutral or acidic media, although a larger proportion of the acid media isolates produced acid from the carbohydrates. Evidence is presented which indicates that different types of streptomycetes were isolated on the acid media, and possible reasons for the presence of these acid-tolerant populations are discussed.
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PMID:Influences of soil acidity on Streptomyces populations inhabiting forest soils. 1 Aug 35

A 29-year-old woman with short bowel syndrome and prolonged starvation developed hyperchloremic metabolic acidosis after initiation of hyoeralimentation with a casein hydrolysate solution. The acidosis was not due to bicarbonate loss but was associated with diminished ability of the kidney to increase urinary acid excretion, particularly titratable acidity. Supplemental parenteral bicarbonate administration was necessary for two weeks until urinary acid excretion rose to normal.
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PMID:Metabolic acidosis after hyperalimentation with casein hydrolysate. Occurrence in a starved patient. 2 2

Although complications of enteral feeding are usually minor, we report an unusual and serious case of oesophageal obstruction after feeding with osmolite, a commonly used polymeric enteral feeding preparation. The patient described underwent rigid oesophagoscopy to remove the feed which had solidified and blocked the entire oesophageal lumen. The procedure resulted in oesophageal perforation which needed surgical repair by thoracolaparotomy and was followed by a difficult postoperative course. In vitro tests showed that all commonly used feeds containing casein (osmolite, ensure, ensure plus, paediasure, fortison, and pulmocare) solidified at a pH of less than 5. Clinifeed (containing dried skim milk) and peptamen (containing peptides) remained liquid at a pH of less than 1. Solidified feed could be liquefied by the addition of pepsin or pancrex V (a pancreatic enzyme formulation). We conclude that solidification could occur in all feeds containing casein and that alternative feeds should be considered in patients with increased gastric acidity. In addition, pepsin or pancrex V could be used to liquefy solidified feed.
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PMID:Oesophageal obstruction during nasogastric feeding. 193 78

Adult rats are able to maintain Ca balance under protein loads that produce Ca loss in adult humans. This species difference was investigated by determining the relationship between protein intake, endogenous acid production (EAP), net acid excretion (NAE), and urinary Ca in adult rats for comparison with a similar study on adult humans. Diets containing 10, 30, and 50% casein were fed in conjunction with proportionate increments in the sulfur amino acid (SAA) methionine (0.6, 1.8, and 3.0%). Urine volume, Ca, sulfate, organic anions, TA (titratable acidity as acid phosphates), and ammonium increased progressively with increases in protein intake, and pH decreased. When protein intake was increased at a constant level of SAA, no increase in urinary Ca, sulfate, and TA or decrease in pH was observed. Both SAA and non-SAA enhanced ammonium excretion but only non-SAA enhanced organic anion excretion, an indicator of incomplete oxidation of organic acids. SAA were responsible for 89 and 91% of the increase in EAP and Ca excretion, respectively, caused by increasing protein intake from 10-30% of the diet. In a comparison experiment, human adults on a high protein intake exhibited a much smaller increase in acid excretion as ammonium, a greater increase as TA, no change in organic anion excretion, and no increase in EAP from non-SAA. The importance of these species differences in acid-base response to a high protein intake in the greater ability of rats to maintain Ca balance on high protein intakes is unclear; however, the smaller fraction of endogenous Ca excreted in the urine of rats is probably an important factor.
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PMID:Effect of a high protein intake on acid-base balance in adult rats. 249 5

Streptococcus faecalis subsp. liquefaciens was examined for proteolysis and development of bitterness in sterile buffaloes' skim milk with and without some additives. Cell population and the pH of milk were the most important factors in the breakdown of casein and development of bitterness. Sodium chloride level, altering the final concentration of bacteria in milk, had a direct role in the production of bitter peptides. Calcium ions up to 5 mM did not affect proteolysis whereas higher concentrations were inhibitory. Electrophoretic analysis of proteose-peptone formed in sterile skim milk with and without NaCl revealed the presence of 3 peptides, 2 of which were probably associated with bitterness. S. faecalis subsp. liquefaciens produced acidity slowly, but was the most acid producer (1.25% after 72 h) of the streptococci. However, milk coagulated enzymatically and the curd shrinkage was related to salt-dependent acidity. Strains of the organism coagulated fresh citrated human plasma within 21 h at 30 degrees C, but without any visible fibrinolysis. The strains also were all alpha-haemolytic with occasionally a very few beta-haemolytic variants on sheep blood agar. On human blood agar, a weak alpha-reaction was given.
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PMID:Some properties of Streptococcus faecalis subsp. liquefaciens isolated from cheese with special reference to production of bitterness. 251 54

This study was conducted to determine the effect of a high protein diet on calcium metabolism in rat. Wistar strain male rats (50 days old) were divided into 5 groups (day 0): control diet (18% casein); high protein diet (18% casein +20% lactalbumin); high protein and 0.1% sodium bicarbonate diet; high protein and 0.2% sodium bicarbonate diet; and high protein and 0.4% sodium bicarbonate diet. On days 0, 1, 3, 5, 7, 9, urine samples were collected and, at the same time, feces were collected from half of the animals in each group. Urinary titratable acidity (TA-HCO3-), ammonium ion (NH4+), and net acid excretion (NAE) were measured as an index of acid-base balance in rat body. Urinary volume was rapidly increased and the increase of urinary volume continued throughout the study in rats fed the high protein diet. Urinary excretions of calcium and phosphorus were increased after day 3 and day 1, respectively, in rats fed the high protein diet. The high protein diet depressed calcium absorption and elevated phosphorus absorption from the digestive tract in rats fed the high protein diet. The high protein diet decreased TA-HCO3-, which was closely correlated with the decrease of NAE. Sodium bicarbonate supplementation to the high protein diet had little effect on urinary calcium excretion and NAE. This study suggested that there was no relationship between metabolic acidosis and hypercalciuria in rats fed the high protein diet.
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PMID:Effects of high protein diet and sodium bicarbonate supplementation on calcium metabolism in rats. 263 82

In previous studies we observed an increased incidence of hyperplasia in the epithelium of the urinary bladder of rats fed cereal-based stock diet supplemented with 6% monosodium glutamate (MSG) for 3 months. Hyperplasia was not enhanced, however, when 6% MSG was fed in a purified casein diet. Further studies have been conducted to identify the dietary factor that caused the different response with the two diets. Feeding MSG had a marked alkalizing effect on the urine. Rats fed purified diet produced urine of higher acidity than did those fed stock diet, a finding attributed to the greater excess of base in the stock diet. When diets with a considerable excess of cations were fed, urinary pH showed a characteristic pattern of widely differing values during a 24-hr period, with high values (pH greater than or equal to 8] for several hours of darkness, when food intake was high, declining during the day to a minimum at the end of the light period. Hyperplasia of the bladder epithelium was induced not only by feeding MSG, but also by feeding 5% of the alkalizing salt KHCO3, both in purified diet and in stock diet. The epithelial response to an alkalizing substance was prevented by simultaneous feeding of the acidifying salt NH4Cl. These findings indicate that the bladder changes induced by MSG are attributable to its alkalizing properties rather than to MSG per se. Moderate to severe hyperplasia of the bladder epithelium was induced also by feeding 5% NH4Cl in purified diet, a procedure accompanied by a further lowering of urinary pH. These findings showed that hyperplasia of the bladder epithelium of rats can be induced both by acidifying and by alkalizing the urine through manipulation of the acid-base balance of the basal diet. There is thus a possibility that, in carcinogenicity studies, administration of compounds to rats in the form of a salt may lead to erroneous conclusions.
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PMID:Induction of hyperplasia in the bladder epithelium of rats by a dietary excess of acid or base: implications for toxicity/carcinogenicity testing. 339 65

Dairy products, including milk, cheese, and casein, can reduce the caries-causing potential of cariogenic substrates as measured in various animal, plaque acidity, and in vitro systems. Although the mechanisms responsible for protection are not completely identified, substances containing Ca and P may contribute to the protective potential by reducing demineralization and/or promoting remineralization of enamel. Casein may reduce demineralization by forming a protective coat on the enamel surface. By means of a rat model, this study evaluated the ability of three casein-free milk mineral concentrates with various levels of whey protein, calcium, and phosphate to modify the cariogenicity of a powdered diet containing 20% sucrose. Analysis of these data indicates that there were no significant differences among groups for weight gain, total food consumption, or feeding frequency, as monitored by a computer-based infrared activity monitor. All three mineral concentrates significantly reduced buccal caries, and two of the three reduced sulcal caries by from 10 to 30%. The analysis further shows that casein-free milk mineral fractions can modify the cariogenicity of sucrose-containing foods in a rat model.
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PMID:Modification of food cariogenicity in rats by mineral-rich concentrates from milk. 349 61

A novel autophosphorylating protein kinase, autophosphorylating protein kinase 500, independent of cyclic AMP, cyclic GMP, calcium, and calmodulin was purified from rat adrenocortical carcinoma 494 by ammonium sulfate fractionation followed by the chromatographic steps of DEAE-cellulose, gel filtration, cyclic AMP-epoxy Sepharose, and phosphocellulose. Sometimes two additional chromatographic purification steps of chromatofocusing and gel filtration were necessary for complete purification. The enzyme was homogeneous as evidenced by one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Sucrose density sedimentation studies indicated that Mr of the enzyme was 490,000, while ultracentrifugal analysis demonstrated a value of 481,400 (+/-7%). The protein was composed of two identical subunits each with Mr = 250,000. The enzyme molecule was slightly asymmetric with frictional and sedimentation coefficients of 1.28 and 18.20, respectively, and a Stokes radius of 66 A. Isoelectric focusing electrophoresis revealed a single peak with pI 4.6, indicating acidity of the protein. The enzyme self phosphorylated one or more of its serine residues. The reaction utilized the terminal phosphate of ATP; GTP was inactive. Divalent cations (5 mM Mn2+ or 10 mM Mg2+) were essential for optimum activity. Autophosphorylating protein kinase 500 did not phosphorylate the commonly used exogenous substrates such as histones, casein, phosvitin, or protamine. Analysis of autophosphorylating protein kinase 500 with rabbit anti-autophosphorylating protein kinase 500 IgG by immunoelectrophoresis and crossed immune electrophoresis demonstrated single arcs of precipitation, confirming the biochemical demonstration of enzyme purification and homogeneity. Indirect immunofluorescence studies revealed an intracytoplasmic localization of the enzyme in cultured and freshly isolated adrenocortical carcinoma 494 cells. Both cell types revealed an intensity of perinuclear enzyme fluorescence, but an absence of the enzyme in the nuclei or nucleoli. The anti-autophosphorylating protein kinase 500 IgG blocked the self-catalyzed phosphorylation of autophosphorylating protein kinase 500, providing immunological support of the biochemical results that autophosphorylation is an intrinsic characteristic of the enzyme. When autophosphorylating protein kinase 500 was incubated with membrane-bound ribosomes, it phosphorylated a Mr = 31,000 protein. This phosphorylation was blocked by the anti-autophosphorylating protein kinase 500 IgG.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Rat adrenocortical carcinoma 494 autophosphorylating protein kinase, autophosphorylating protein kinase 500. Purification, biochemical and immunological characterization, and substrate specificity. 637 Oct 13

Japanese mint (Mentha arvensis) oil (JMO) can be used effectively as fumigant against Sitophilus oryzae in stored sorghum. The effect of JMO at a dose of 166 microliter/l of space on nutrient composition and protein quality was studied in infested and uninfested sorghum grains stored for 3 months. The results revealed non significant effect of JMO on gran moisture, total ash, crude fibre, crude fat, crude protein and fat acidity in infested and uninfested grains at the end of 3 months storage. The JMO treatment had small but significant effect on reducing and non-reducing sugars. The values of Protein Efficiency Ratio (PER) for uninfested JMO treated grains, infested JMO treated grains and for untreated control stored for 3 months were 1.11, 1.07 and 1.09, respectively against control casein diet for which it was 2.15.
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PMID:Effect of Japanese mint (Mentha arvensis) oil as fumigant on nutritional quality of stored sorghum. 779 58


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