Bovine milk antibodies against cell surface protein antigen PAc-glucosyltransferase fusion protein suppress cell adhesion and alter glucan synthesis of Streptococcus mutans.
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Cell surface protein antigen (PAc) and glucosyltransferases (GTF) produced by Streptococcus mutans are considered major colonization factors of the organism, and the inhibition of these factors is thought to prevent dental caries. In this study, 8-mo-old pregnant Holstein cows were immunized with fusion protein PAcA-GB, a fusion of the saliva-binding alanine-rich region (PAcA) of PAc with the glucan binding (GB) domain of GTF-I, an enzyme catalyzing the synthesis of water-insoluble glucan from sucrose. High titers of immunoglobulin antibodies specific for the fusion protein were found in normal milk after reimmunization, and they persisted for approximately 3 mo. The immunoglobulin G (IgG) antibodies against PAcA-GB were purified from immunized milk. The antibodies significantly inhibited the adhesion of S. mutans cells to saliva-coated hydroxyapatite beads. IgG antibodies purified from immunized milk also inhibited total glucan synthesis by cell-associated GTF preparation and GTF-I from S. mutans. The immunized milk may be useful as a means of passive immunization for the prevention of dental caries in humans. (+info)
Registered designation of origin areas of fermented food products defined by microbial phenotypes and artificial neural networks.
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Cheese produced from raw ewes' milk and chourico, a Portuguese dry fermented sausage, are still produced in a traditional way in certain regions of Portugal by relying on colonization by microbial populations associated with the raw materials, equipment, and local environments. For the purpose of describing the product origins and types of these fermented foods, metabolic phenotypes can be used as descriptors of the product as well as to determine the presence of compounds with organoleptic value. The application of artificial neural networks to the metabolic profiles of bacterial isolates was assayed and allowed the separation of products from different regions. This method could then be used for the Registered Designation of Origin certification process of food products. Therefore, besides test panel results for these traditionally produced food products, another tool for validating products for the marketplace is available to the producers. The method can be improved for the detection of counterfeit products. (+info)
Effect of milk proteins on adhesion of bacteria to stainless steel surfaces.
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Stainless steel coupons were treated with skim milk and subsequently challenged with individual bacterial suspensions of Staphylococcus aureus, Pseudomonas fragi, Escherichia coli, Listeria monocytogenes, and Serratia marcescens. The numbers of attached bacteria were determined by direct epifluorescence microscopy and compared with the attachment levels on clean stainless steel with two different surface finishes. Skim milk was found to reduce adhesion of S. aureus, L. monocytogenes, and S. marcescens. P. fragi and E. coli attached in very small numbers to the clear surfaces, making the effect of any adsorbed protein layer difficult to assess. Individual milk proteins alpha-casein, beta-casein, kappa-casein, and alpha-lactalbumin were also found to reduce the adhesion of S. aureus and L. monocytogenes. The adhesion of bacteria to samples treated with milk dilutions up to 0.001% was investigated. X-ray photoelectron spectroscopy was used to determine the proportion of nitrogen in the adsorbed films. Attached bacterial numbers were inversely related to the relative atomic percentage of nitrogen on the surface. A comparison of two types of stainless steel surface, a 2B and a no. 8 mirror finish, indicated that the difference in these levels of surface roughness did not greatly affect bacterial attachment, and reduction in adhesion to a milk-treated surface was still observed. Cross-linking of adsorbed proteins partially reversed the inhibition of bacterial attachment, indicating that protein chain mobility and steric exclusion may be important in this phenomenon. (+info)
Possible protective effect of milk, meat and fish for cerebrovascular disease mortality in Japan.
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Cerebrovascular disease was a leading cause of death from 1955 to 1980 in Japan. The mortality rate from this disease has decreased sharply in recent decades. This downward trend seems to correspond to the dietary habits of Japanese. Data from a large prospective cohort study were analyzed to examine the association between dietary habits and cerebrovascular disease mortality in Japan. The subjects for this analysis were 223,170 men and women aged 40 to 69 at baseline in December 1965. There were 6,168 deaths in men and 4,862 deaths in women due to cerebrovascular disease (ICD7: 330-334) during the follow-up period from January 1966 to December 1981. Rate ratio (RR) and 95% confidence interval (95% CI) adjusted for sex, attained age, follow-up period, prefecture, cigarette smoking, alcohol drinking and occupation was used for comparison. In this study, the risk of mortality from cerebrovascular disease was inversely associated with dairy milk, meat and fish consumption. Therefore the joint effect of dairy milk, meat and fish (DMF) as animal fat and protein was of interest. In the binary analysis, DMF (D, M, F) means the combination of dairy milk (1-3 times/week or more), meat (1-3 times/week or more) and fish (4 times/week or more). Thus DMF (d, m, f) was the reference group having dairy milk (less than 1 time/week), meat (less than 1 time/week) and fish (less than 4 times/week). For the disease, the RR of DMF (D, M, F) was 0.68 with 95% CI of 0.63 to 0.74, relative to the reference group. Furthermore the joint effect of DMF was more strongly associated with cerebral haemorrhage (ICD7: 331, DMF (D, M, F); RR: 0.63, 95% CI: 0.55-0.70) than with cerebral embolism and thrombosis (ICD7: 332, DMF (D, M, F); RR: 0.79, 95% CI: 0.70-0.89). These findings suggest that the increasing intake of animal fat and/or protein may have played a key role in reducing cerebrovascular disease in Japan. (+info)
Factor analysis of digestive cancer mortality and food consumption in 65 Chinese counties.
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Dietary factors were analyzed for the regional difference of GI tract cancer mortality rates in China. Sixty-five rural counties were selected among a total of 2,392 counties to represent a range of rates for seven most prevalent cancers. The dietary data in the selected 65 counties were obtained by three-day dietary record of households in 1983. The four digestive cancer mortality rates (annual cases per 100,000 standardized truncated rates for ages 35-64) and per capita food consumption were analyzed by the principal components factor analysis. Esophageal cancer associated with poor area, dietary pattern rich in starchy tubers, and salt, lack of consumption of meat, eggs, vegetables and rice. Stomach cancer seemed to be less associated with diet in this study because of its small model Kaiser-Meyer-Olkin (KMO) measure of sampling adequacy, suggesting some other carcinogenic factors would play more important role in the development of this cancer in China. The colon and rectal cancer showed close relation to diet; rich in sea vegetables, eggs, soy sauce, meat and fish, while lack in consumption of milk and dairy products. Rapeseed oil was more important risk factor for colon cancer than that of rectum. Rice, processed starch and sugar were closely associated with colon cancer, supporting the insulin/colon cancer hypothesis. (+info)
Intestinal colonisation of gnotobiotic pigs by Salmonella organisms: interaction between isogenic and unrelated strains.
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The effect of intestinal colonisation by a Salmonella strain on the establishment in the gut of an isogenic mutant administered orally 24 h after the first strain was studied in gnotobiotic pigs. Irrespective of the clinical outcome of the infection, the extensive colonisation of one Salmonella strain prevented a similar degree of colonisation by an otherwise isogenic antibiotic resistant strain; in some cases the second strain was hardly detectable. The poor colonisation of the challenge Salmonella strains was generally reflected in very low counts of organisms in the tissues. Colonisation by a strain of Escherichia coli reduced the rate of establishment of an isogenic E. coli, strain but did not prevent colonisation by an S. Typhimurium strain. S. Typhimurium with mutations in the tsr (serine chemotaxis receptor protein) or oxrA (transcriptional regulator of anaerobic metabolism) genes did not inhibit colonisation. Mutations in cya (adenylate cyclase), tar and trg (chemotaxis receptor proteins for aspartate and ribose respectively) genes were less inhibitory, while motB (non-motile) and cheR (impaired motility) mutants were fully inhibitory. (+info)
Influence of postruminal supplementation of methionine and lysine, isoleucine, or all three amino acids on intake and chewing behavior, ruminal fermentation, and milk and milk component production.
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Four multiparous Holstein cows were fed a basal diet balanced with the Cornell Net Protein and Carbohydrate System (CNCPS). Diets were formulated to be co-limiting in intestinally absorbable supplies of methionine, lysine, and isoleucine. Cows were supplemented with no amino acids (control); lysine and methionine in a ruminally protected form; isoleucine by abomasal infusion; or lysine, methionine, and isoleucine in a 4x4 Latin square arrangement of treatments with 28-d periods. Performance of cows on all treatments was lower than expected due to low intake of DM that could have been caused by the high fiber level of the basal diet. This high fiber level was likely responsible for the high daily chewing times for cows fed all diets, which was consistent with the high ruminal pH values. Intake of DM and its components were not influenced by any treatment. Milk protein percentage tended to be higher when cows were fed diets supplemented with ruminally protected lysine and methionine; however, production of milk, milk fat, and milk lactose were not affected by any treatment. Cows tended to have a higher milk lactose proportion and tended to produce more milk and milk lactose when they were abomasally infused with isoleucine alone. However, when cows were supplemented with all three amino acids, milk production and composition did not differ from that of cows fed the unsupplemented diet. Use of the CNCPS to evaluate the performance of the cows fed the unsupplemented diet suggested that these cows may have been colimited by intestinally absorbable supplies of lysine, isoleucine, and methionine in addition to metabolizable protein. Evaluation of the unsupplemented diet with an alternate model, Shield, suggested that cows fed the unsupplemented diet may have been colimited by intestinally absorbable supplies of lysine, isoleucine, and arginine. Results suggest that enhanced delivery of intestinally absorbable isoleucine may stimulate milk lactose synthesis. (+info)
Apelin, the natural ligand of the orphan receptor APJ, is abundantly secreted in the colostrum.
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By using a strategy that we have developed to search for the ligands of orphan seven-transmembrane-domain receptors [S. Hinuma et al., Nature 393 (1998) 272-276], we have recently identified a natural ligand, apelin, for the orphan 7TMR, APJ [K. Tatemoto et al., Biochem. Biophys. Res. Commun. 251 (1998) 471-476]. In this paper, we isolated rat and mouse apelin cDNAs, and analyzed the tissue distribution of apelin mRNA in rats. Although apelin mRNA was widely detected in a variety of tissues, the highest expression of apelin mRNA was detected in the mammary gland of pregnant rats. In the mammary gland, biologically active apelin and its mRNA considerably increased during pregnancy and lactation, and reached a maximal level around parturition. Moreover, a large amount of apelin (14-93 pmol/ml) was found to be secreted in the bovine colostrum, and it was still detectable even in commercial bovine milk. Since apelin partially suppressed cytokine production by mouse spleen cells in response to T cell receptor/CD3 cross-linking, the oral intake of apelin in the colostrum and milk might modulate immune responses in neonates. (+info)