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Biomedical subjects

K M Shahani

Publications and source records attributed to K M Shahani.

At least 19 recordsLinked to original sources
PubMed1997

Nonlipopolysaccharide component(s) of Lactobacillus acidophilus stimulate(s) the production of interleukin-1 alpha and tumor necrosis factor-alpha by murine macrophages.

Previous studies in our laboratory suggested that Lactobacillus acidophilus strain DDS-1 (LA1) has a suppressive effect on chemically induced tumors in experimental animals. In an effort to understand the possible mechanisms underlying this effect, we investigated the ability of LA1 to induce the production of interleukin-1 alpha (IL-1 alpha) and tumor necrosis factor-alpha (TNF-alpha), which have potent cytocidal and cytostatic effects on tumor cells. The mouse macrophage cell line RAW264.7 was incubated with live or heat-killed cells of four strains of L. acidophilus or Bifidobacterium bifidum. Escherichia coli was used as a source of lipopolysaccharide that is known to induce the above cytokines. The amount of the cytokines present in the culture fluid was quantitated by an enzyme-linked immunosorbent assay. LA1 induced the production of higher levels of IL-1 alpha and TNF-alpha than other lactobacilli and bifidobacteria. Stimulation of the production of the cytokines was not due to the lipopolysaccharide (LPS) component, since LPS at concentrations equivalent to, or 100-fold greater than, that of LA1 induced only negligible amounts of IL-1 alpha and TNF-alpha. These results reveal that non-LPS component(s) of LA1 stimulate(s) the production of IL-1 alpha and TNF-alpha by macrophages, indicating that this organism stimulates the production of immunologic factors.

Animals↗
PubMed1990

Influence of a dried Bacillus subtilis culture and antibiotics on performance and intestinal microflora in turkeys.

Two experiments, each involving a 3 x 2 factorial design, were conducted with Large White Nicholas turkeys. The first experiment involved three antibiotic treatments: an unmedicated control diet, the diet plus 44 ppm of penicillin-streptomycin (1:3), and the diet plus 44 ppm of Zn bacitracin; each diet was fed in the presence and absence of a dried Bacillus subtilis culture to females 0 to 16 wk of age. Antibiotic supplements increased body weight at 12 (P less than .05) and 16 (P less than .001) wk of age. Body weight and feed efficiency were not significantly affected by feeding the B. subtilis culture in this experiment. The dietary B. subtilis culture significantly increased B. subtilis counts in the crop and cecum but failed to influence intestinal Lactobacillus or Escherichia coli counts. The second experiment also involved three antibiotic treatments: an unmedicated control diet, 44 ppm of Zn-bacitracin, and 2.2 ppm of bambermycins, and each diet was fed in the presence and absence of the dried B. subtilis culture to male birds from 0 to 20 wk of age. Increased body weight gain was observed in birds receiving the B. subtilis culture at 12 wk (P less than .01). Feed efficiency of birds receiving the B. subtilis culture was improved (P less than .05) at 20 wk. Birds receiving bambermycins had greater body weights (P less than .05) at 12 and 16 wk of age than birds receiving Zn bacitracin or the control diet. Livability was not affected by the B. subtilis culture or the antibiotic treatments in either experiment.

Animal Feed↗
PubMed1989

Anticholesteremic property of Lactobacillus acidophilus yogurt fed to mature boars.

Three strains of Lactobacilus acidophilus (LA) were isolated from the feces of mature boars that were not being fed antibiotics from the Nebraska Gene Pool (NGP). All three LA isolates were screened in vitro for anticholesteremic and antimicrobial activities. One strain, LA16, caused the greatest reduction in cholesterol and inhibited both Bacillus subtilis and Escherichia coli the most. LA16 was used to produce 16, 18.9-liter quantities of acidophilus yogurt (AY), over a period of 8 wk, for use as a feed ingredient in diets for the NGP boars. Colony forming units (cfu), pH, protein, energy, Ca and P were consistent across all 16 batches of yogurt. All of the 18 boars were fed a high-cholesterol diet for a period of 56 d at a rate of 2.268 kg/(hd.d) to furnish 6.661 g/(hd.d) of cholesterol. Nine of the boars then were fed 1.81 kg/(hd.d) of a second diet that was supplemented with .454 kg/(hd.d) of AY. The other nine boars were fed the original diet. Cholesterol intake was the same for the two dietary treatments. Blood samples were collected weekly from the brachial-jugular region and the sera were analyzed for lipids. Acidophilus yogurt reduced serum cholesterol (P less than .01) and low density lipoproteins (P less than .08), but it had no effect on serum triglycerides (P greater than .23) or on high density lipoproteins (P greater than .11).

Animal Feed↗
PubMed1983

The effect of processing and storage on key enzymes, B vitamins, and lipids of mature human milk. I. Evaluation of fresh samples and effects of freezing and frozen storage.

A study was initiated to evaluate the effects of several methods of processing and storage on key enzymes, B vitamins, and lipid components of mature human milk. In order to establish standard values for the nutrient components with which to compare processed samples, a total of 30 individual raw samples of mature human milk were analyzed. There was considerable sample to sample variation as indicated by the large range of values for each component. Freezing and frozen storage had little effect on the enzymes of pooled samples of milk. Lactoperoxidase activity decreased from 36 in raw pooled samples to 17 in pooled samples slow frozen and stored for 3 months at -25 degrees C (P less than 0.05). Similarly, quick freezing and storage for 3 months significantly decreased the lactoperoxidase activity of pooled samples from 93 to 14 (P less than 0.05). Quick freezing and frozen storage tended to increase lipase activity although the changes were not significant. Freezing and frozen storage did not significantly affect the levels of biotin, niacin, and folic acid. Similarly, the total lipid fatty acid level and relative % of each fatty acid were not significantly different in the frozen samples as compared to the raw samples.

Enzymes↗
PubMed1982

Ion exchange separation of the antitumor component(s) of yogurt dialyzate.

The active antitumor component of yogurt obtained by dialysis was further fractionated by ion exchange chromatography into acidic, basic, and neutral fractions, which were analyzed for activity by in vitro agar diffusion, cell culture, and in vivo mouse assay. Neither dialysate nor fractions showed any antitumor activity when tested by agar diffusion or cell culture techniques. When tested by in vivo mouse assay, the dialyzate as well as the anionic fraction showed significant inhibitory activity. The cationic fraction showed no activity. There was no direct relationship between stage of purification and antitumor activity. Moreover, the response of the dialyzate or anionic fraction was not linear with concentration. The antitumor activity of the yogurt fraction(s) may be related to a host-mediated immunological reaction or "activation" of the "inactive" component(s).

Animals↗
PubMed1981

Antitumor component(s) of yogurt: fractionation.

Two methods of fractionation were employed to separate antitumor component(s) from yogurt. First, yogurt was separated by dialysis. Although feeding of the dialyzate fraction to mice inoculated with Ehrlich ascites tumor cells resulted in 32.9% inhibition of tumor cell counts and 23.5 to 26.3% reduction of deoxynucleic acid content of ascitic fluid, feeding of the yogurt retentate did not reduce tumor proliferation. Second, an aqueous fraction of yogurt was prepared by removal of the ether soluble matter. Administration of aqueous fraction at 2 mg/mouse intravenously resulted in 25.1 to 32.3% less cell growth whereas intraperitoneal inoculation resulted in only 15.0 to 15.9% reduced tumor proliferation. Antitumor activity may be due to a component(s) with a molecular weight less than or equal to 14,000, and it presumably is not bound chemically to any larger compound because it could be separated by dialysis.

Animals↗
PubMed1980

Human milk ribonuclease.

Two components having ribonuclease (EC 3.1.27.5) activity were isolated from human milk. Each component of human milk ribonuclease (RNAase) moved at a slightly different rate when electrophoresed on polyacrylamide gel but at the same rate when ultracentrifuged. The major component had a molecular weight of approx. 14 000, an isoelectric point of pH 7.9, and exhibited a broad absorbance maximum between 277 and 281 nm. Human milk RNAase hydrolyzed yeast RNA, poly(cytidylic acid) and poly(uridylic acid) but not DNA, poly(adenylic acid) or poly(guanylic acid). Maximum activity occurred at pH 7.7 and 60 degrees C. Amino acid analysis of the major component revealed a large number of alanine, valine, glycine and aspartic acids but no tryptophan or free sulfhydryl groups. Lysine was the N-terminal amino acid. Tryptic hydrolysis yielded 18 peptides, some of which are similar to those from bovine pancreatic RNAase. Human milk RNAase activity was increased in the presence of NaCl, KCl and sodium citrate and decreased by CaCl(2), MgCl(2), FeSO(4), ZnSO(4) and CuSO(4).

Amino Acid Sequence↗
PubMed1980

Role and significance of enzymes in human milk.

Although human milk generally contains higher levels of enzymes than bovine milk, little definitive information is available concerning their role or significance. The enzyme levels in human milk as compared to bovine milk and levels in human colostrum versus normal milk are summarized. The few most widely studied human milk enzymes are discussed in more detail. Evidence is presented to support the views that 1) lipoprotein lipase and ribonuclease are probably spilled into the milk from the blood; 2) lysozyme is spilled from the secretory epithelial cells; 3) lactate and malate dehydrogenases, glucose-6-phosphate dehydrogenase, and lactose synthetase are synthesized in the mammary gland in response to hormonal stimuli; and 4) bile salt stimulated lipase, diastase, protease, and lysozyme are present in sufficient quantities to aid infants in growth and nutrition. Consideration must be given to standardizing the various enzyme assay procedures and activity units so that meaningful comparisons between various studies could be made.

Animals↗
PubMed1979

The use of immobilized enzymes in the food industry: a review.

The production of high fructose corn syrups was greatly facilitated by the use of immobilized glucose isomerase. Similarly, in Japan, the fermentation industry proved its processing efficiency for amino acids through the use of immobilized amino acid acylase. This article discusses the use of soluble enzymes in the food industry followed by a section on the various available methods to immobilize enzymes. Once enzymes are immobilized, many of their operational parameters could be altered. Rationale for the determination of the effects of immobilization is provided. A relatively new concept is the use of a single matrix for immobilizing more than one enzyme. Immobilized multi-enzyme systems offer many attractive advantages; however, such a process also raises some interesting questions about kinetics. These questions and their suggested answers are discussed in the penultimate section. The major emphasis of this article is on the use of immobilized enzymes in the food industry. Two systems--amino acylase and glucose isomerase--have been demonstrated to be techno-economically feasible. Immobilization of other enzymes, such as glucoamylase, lactase, protease, and flavor modifying enzymes, has received some attention. The potential of these new systems are also discussed.

Amidohydrolases↗
PubMed1979

Use of total whey constituents for human food.

In recent years, utilization of whey has been felt to be an inexorable necessity in view of the current requirements for alleviating environmental pollution as well as using available nutrients for feeding the malnourished segments of human population. Presence of several nutritionally important constituents having excellent functional characteristics enhances opportunities for a wide-range application of whey and whey constituents in the food industry. Technology is being developed to utilize whey for the manufacture of a variety of new food products as well as for the replacement of comparatively costly food ingredients. Various aspects of utilization of whey for human nutrition are described.

Beverages↗
PubMed1979

Nutritional and healthful aspects of cultured and culture-containing dairy foods.

Nutritional and therapeutic qualities of fermented dairy products are reviewed. Partial hydrolysis of milk constituents (proteins, fats, and lactose) in yogurt, cheese, and other cultured dary foods appears to contribute to their increased digestibility. Lactase and other constituent enzymes of various culturing organisms should contribute to assimilation of lactose by lactose intolerant individuals. Several lactic cultures synthesize certain B-vitamins in fermented dairy products. In contrast, directly acidified dairy products do not exhibit such enhancement in B-vitamins. The hypocholestremic effect of milk is enhanced by fermentation or inclusion of lactic cultures. Lactobacillus acidophilus, Lactobacillus bulgaricus and other lactic organisms produce antimicrobial agents and natural antibiotics. However, production of natural antibacterial substances by different strains of the same species vary widely. These metabolites in cultured dairy products may be responsible for increased shelf life of the foods by inhibiting a wide spectrum of food spoilage organisms. Also, consumption of cultured products containing such natural antibacterial substances may provide the consumer with protection against disease organisms. Unfermented milk containing a specific culture or strain may be consumed to invest organisms for projected beneficial effects.

Animals↗
PubMed1977

Preparation and properties of immobilized papain and lipase.

Papain and lipase were immobilized on derivatized Sepharose 4-B. The activated agarose had a binding capacity of 1.2 micronmol amino groups/ml packed agarose or 17 mg proteins/g dry agarose. The immobilized enzyme preparations were tested for the effects of pH of assay, temperature of assay, and substrate concentrations. The effect of 6M urea on the activity of papain was also determined. Soluble forms of the enzymes were used for comparison. Immobilization of the enzymes resulted in slightly different pH and temperature optima for activities. For immobilized papain Km(app) was similar to the one observed with soluble papain. Immobilization of lipase, however, cause a decrease in Km values. The immobilized enzyme preparations were stable when stored at 4 degrees C and pH 7.5 for periods up to eight months. The soluble enzymes lost their activity within 96 hr under similar storage conditions. Immobilized papain did not lose any activity after treatment with 6M urea for 270 min, whereas soluble papain lost 81% of its activity after the urea treatment, indicating that the immobilization of papain imparted structural and conformational stability to this enzyme.

Enzymes, Immobilized↗
PubMed1976

B-complex vitamins in cultured and acidified yogurt.

Studies were to determine the effect of various factors upon B-vitamin content of cultured yogurt and to compare the B-vitamin contents of cultured and direct acidified yogurt. Incubation of yogurt culture at 42 C for 3 h yielded maximum vitamin synthesis concurrent with optimal flavor and texture qualities. A method was standardized for the manufacture of direct acidified yogurt involving the use of Stabilac acidulant and nonfat dry milk, Carboxymethyl cellulose, gelatin, and Starite. Acidified yogurt showed a slightly higher content of certain B-vitamins than the cultured yogurt due to the contribution made by various food additives. Both cultured and acidified yogurt showed good keeping quality and freedom from microbial contaminants during storage at 5 C for 16 days. However, folic acid and vitamin B12 contents decreased 29 and 60% in cultured yogurt and 48 and 54% in acidified yogurt.

Dairy Products↗
PubMed1976

Bovine pancreatic lipase.I.Isolation, homogeneity, and characterization.

Bovine pancreatic lipase was isolated in pure form by lyophilization of fresh bovine pancreas, extraction of the enzyme with sucrose solution, fractional precipitation with ammonium sulfate and acetone, followed by chromatography on Sephadex G-100. The specific activity of the purest lipase fraction was 1750 micromoles fatty acid, liberated in 30 min per milligram of protein, indicating a purification of approximately 473-fold, with an overall yield of about 42%. Homogeneity of the enzyme was confirmed by rechromatography on Sephadex G-100 as well as with the gel electrophoretic and ultracentrifugal techniques. The purified enzyme gave a typical protein ultraviolet absorption spectrum with maximum absorption at 276 nm and minimum at 252 nm. The purified enzyme exhibited a single pH optimum of 8.8 and an isoelectric point near pH 5.5. Its optimum temperature was 37 C, and its optimum substrate concentration was 10%. These properties resembled those of milk lipase.

Animals↗
PubMed1976

Relationship between composition and stability of bovine milk lysozyme.

The amino acid analysis, peptide mapping, and heat stability of bovine milk lysozyme are presented. The bovine milk lysozyme molecule contains approximately 154 amino acids and is strikingly different in amino acid content from human milk lysozyme and egg white lysozyme. Tryptic hydrolysis yielded 26 peptides, all of which are unique from tryptic peptides of human milk lysozyme and egg white lysozyme. In addition, bovine milk lysozyme was more heat stable than human milk lysozyme at pH 4.0 but more labile at pH 7.0 and 9.0. Possible explanations for the differences in heat stability are discussed.

Amino Acids↗