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At least 19 recordsLinked to original sources
PubMed1977

Enzymic characteristics of fat globule membranes from bovine colostrum and bovine milk.

Fat globule membranes have been isolated from bovine colostrum and bovine milk by the dispersion of the fat in sucrose solutions at 4 degrees C and fractionation by centrifugation through discontinuous sucrose gradients. The morphology and enzymic characteristics of the separated fractions were examined. Fractions comprising a large proportion of the total extracted membrane were thus obtained having high levels of the Golgi marker enzymes UDP-galactose N-acetylglucosamine beta-4-galactosyltransferase and thiamine pyrophosphatase. A membrane-derived form of the galactosyltransferase has been solubilized from fat and purified to homogeneity. This enzyme is larger in molecular weight than previously studied soluble galactosyltransferases, but resembles in size the galactosyltransferase of lactating mammary Golgi membranes. In contrast, when fat globule membranes were prepared by traditional procedures, which involved washing the fat at higher temperatures, before extraction, galactosyltransferase was not present in the membranes, having been released into supernatant fractions, When the enzyme released by this procedure was partially purified and examined by gel filtration, it was found to be of a degraded form resembling in size the soluble galactosyltransferase of milk. The release is therefore attributed to the action of proteolytic enzymes. Our observations contrast with previous biochemical studies which suggested that Golgi membranes do not contribute to the milk fat globule membrane. They are, however, consistent with electron microscope studies of the fat secretion process, which indicate that secretory vesicle membranes, derived from the Golgi apparatus, may provide a large proportion of the fat globule membrane.

Animals↗
PubMed1979

The serum-free growth of Balb/c 3T3 cells in medium supplemented with bovine colostrum.

Bovine milk contains growth promoting factors that stimulate DNA synthesis and cell division in confluent monolayers of quiescent Balb/c 3T3 cells. The growth factor activity was highest in colostrum obtained within 24 hours after birth of a calf. Samples of milk obtained 32 hours and 60 hours after birth were 20% and 1% as active respectively as was a sample obtained 8 hours after birth in stimulating DNA synthesis. No activity was detectable 3 days after birth or thereafter. A similar temporal dependence was found in sheep's milk. Bovine colostrum obtained on the day of a calf's birth can be substituted for serum and will support the growth of sparse Balb/c 3T3 cells to confluence. In Dulbecco's modified Eagles's medium (DMEM) supplemented with 2.5% (vol/vol) bovine colostrum, the number of Balb/c 3T3 cells in a dish increased 35-fold, from 2.0 X 10(4) cells to 7 X 10(5) cells. The generation time was approximately 38 hours. Proliferation of cells was characterized by formation of clusters of confluent Balb/c 3T3 cells which were smaller in size and more tightly packed than were Balb/c 3T3 cells grown to confluence in serum. No proliferation was detected in DMEM supplemented with milk obtained 10 days after birth of a calf or in DMEM supplemented with bovine serum albumen.

Animals↗
PubMed1978

Inhibition of rat and bovine trypsins and chymotrypsins by soybean, bovine basic pancreatic, and bovine colostrum trypsin inhibitors.

1. Bovine (Bos taurus) trypsin and trypsin activity in rat (Rattus norvegicus) pancreatic extract were inhibited by soybean trypsin inhibitor and by bovine basic pancreatic and colostrum inhibitors. 2. Bovine alpha-chymotrypsin was inhibited by soybean and bovine basic pancreatic inhibitors but only weakly by colostrum inhibitor. 3. Chymotrypsin activity in rat pancreatic extract was due to at least three different components against all of which the inhibitors were largely ineffective. 4. It is concluded that bovine colostrum inhibitor has a more limited inhibition spectrum than the phylogenetically related basic pancreatic inhibitor which, in turn, is less active against rat than against bovine enzymes.

Animals↗
PubMed1976

[Nepsilon-(beta-Aspartyl)lysine and Nepsilon-(gamma-glutamyl)lysine crosslinkings in bovine colostrum (author's transl)].

In bovine colostrum which was defatted and totally hydrolyzed by proteolytic enzymes, the isopeptides Asp Lys and Glu Lys were identified by ion-exchange chromatography and preparative separation. Isopeptides were identified in two of seven samples of colostrum. It is still to be clarified whether there is a correlation between the amound of gamma-glutamyltransferase and the appearance of these crosslinkings.

Animals↗
PubMed1977

Immunoglobulin M associated with secretory component and immunoglobulin A deficiency in bovine colostrum.

Immunoglobulin (Ig) M purified from bovine colostrum was examined by an immunodiffusion analysis with antisecretory IgA serum and was found to be associated with a secretory component. Some of the combined proteins were dissociated if treated with 5 M guanidine-HCl and others were not. Another immunodiffusion analysis of 23 specimens of colostrum led to the finding that certain colostrums were deficient in IgA, even though they contained IgG and IgM.

Animals↗
PubMed1977

The effect of trypsin and chymotrypsin on the bactericidal activity and specific antibody activity of bovine colostrum.

Digestion of bovine colostral whey with trypsin or chymotrypsin caused a progressive loss of the complement-mediated bactericidal activity of naturally-occurring colostral antibodies of E. coli 0111. Bactericidal activity was associated primarily with IgG1 immunoglobulin and to a lesser extent with IgM. Chymotrypsin preferentially attacked IgM, destroying its antibacterial activity and producing an apparent decrease in its mol wt. Trypsin preferentially attacked IgG1, but loss of antibacterial activity was in this case not accompanied by a decrease in molecular weight. Using colostral whey with antiperoxidase activity it was shown that the kinetics of loss of specific antibody activity were similar to those of loss of bactericidal activity. It is therefore suggested that trypsin may cause a loss of specific antibody activity of colostral IgG1 without cleaving the immunoglobulin molecule.

Animals↗
PubMed1978

Secretion and immunochemical properties of the trypsin inhibitor from bovine colostrum.

A trypsin inhibitor was isolated from bovine colostrum by affinity chromatography. Immunoelectrophoresis detected two immunogenic components in the isolated inhibitor, but only one of these was specific for the inhibitor; the other one was identical with an antigen present in liver, kidney, spleen, adrenal, thyroid, thymus, brain, ovarian, testicular and udder tissue and in bull seminal plasma. Using immunoabsorption and immunofluorescence it was shown that the antigens specific for the trypsin inhibitor of colostrum could be demonstrated only in the tissue of an udder that is secreting colostrum. The inhibitor is secreted by the secretory epithelium of the milk alveoli of the udder, during the period when the latter secretes colostrum. This inhibitor was not detected in the milk. Cross-reaction between antisera to colostral inhibitor and basic pancreatic inhibitor or seminal plasma inhibitors yielded negative results. Antiserum to bovine colostral inhibitor showed a positive reaction with inhibitor isolated from porcine colostrum.

Animals↗
PubMed1976

Opsonic activity and O-agglutinins against Escherichia coli in bovine colostrum.

Anticolibacillus antibody activity was examined in 16 samples of bovine colostrum by O-agglutination test with 6 serotypes of Escherichia coli, and its correlation with the manifestation of diarrhea was analyzed for newborn calves fed these colostrums. The 4 colostrums fed to newborn calves having diarrhea within a few days after birth had significantly lower agglutinin titers for all the serotypes tested than did the other colostrums. Other newborn calves fed on the remaining 12 colostrums did not manifest clinical signs of enteric disorders. The agglutinin spectrum against the E coli serotypes was similar between colostrum samples from the same stockfarm, but variable among the farms from which the colostrum had been collected. The agglutinin activity was sensitive to 2-mercaptoethanol and was found mainly in the macroglobulin fraction of gel filtration, indicating that the activity was due to antibodies of the immunoglobulin M type. This was evidenced directly by the agglutination test of purified immunoglobulins. Opsonic activity of colostrum and immunoglobulins purified therefrom was estimated by the rate of decrease in the number of viable E coli injected into mouse peritoneal cavity. The results indicated that the opsonic activity in colostrum was also attributed mainly to immunoglobulin M antibodies, although the contribution of immunoglobulin A and G antibodies was not ruled out. A part of the opsonic activity in colostrum seemed due to heat-labile component(s) as well.

Agglutinins↗
PubMed1978

The effect of trypsin and chymotrypsin on the antibacterial activity of complement, antibodies, and lactoferrin and transferrin in bovine colostrum.

The effect of trypsin and chymotrypsin on antibacterial factors in bovine colostrum has been studied. Endogenous complement in colostrum was extremely sensitive to both enzymes. IgM was attacked by chymotrypsin but not by trypsin. Trypsin slowly attacked IgG1, causing loss of biological activity due to cleavage of both light and heavy chains. IgG1 was only very slightly attacked by chymotrypsin. Lactoferrin and transferrin in the iron-free state were both susceptible to proteolysis, but the iron saturated forms were more resistant and tended to give rise to stable iron-binding fragments.

Animals↗
PubMedDate not supplied

Bactericidal and haemolytic activity of complement in bovine colostrum and serum: effect of proteolytic enzymes and ethylene glycol tetraacetic acid (EGTA).

Bovine colostral whey (CW) possessed heat-labile bactericidal activity against an enteropathogenic serum-susceptible strain of Escherichia coli. Activity was readily destroyed by trypsin or rat pancreatic juice, and less readily by chymotrypsin. Loss of activity due to trypsin, but not by chymotrypsin, could be prevented by addition of excess bovine colostral trypsin inhibitor. A second enteropathogenic strain of E. coli was killed by CW only if exogenous complement was added. This activity was maintained, however, even if the complement was heated 56 degrees C during 15 min. CW possessed only very weak haemolytic activity against sensitised rabbit erythrocytes, but could augment the haemolytic titre of bovine serum and could partially restore haemolytic activity to heat-inactivated bovine serum. These observations indicate that low but significant amounts of complement may occur in bovine colostrum. Sequestration of Ca++ by EGTA abolished all bactericidal and haemolytic activity in CW, and reduced but did not completely abolish these activities in bovine serum or in CW + exogenous complement. The activity of colostral complement therefore appears to be mediated entirely by the classical pathway whereas the alternate pathway may play some part in the bactericidal and haemolytic activities of bovine serum or of CW + exogenous complement.

Calcium↗
PubMed1977

Enzymatic properties of beta-D-galactoside alpha2 leads to 6 sialytransferase from bovine colostrum.

The substrate specificity and kinetic properties of a pure sialyltransferase from bovine colostrum have been examined. The transferase appears to incorporate sialic acid into the sequence, NeuAcalpha2 leads to 6Galbeta1 leads to 4GlcNAc, which is commonly found in glycoproteins. It has a strict substrate specificity for CMP-NeuAc and forms only the alpha2 leads to 6 sialyl linkage with beta-D-galactosides. N-Acetyllactosamine (Galbeta1 leads to 4GlcNAc) and asialo-glycoproteins containing the N-acetyllactosaminyl linkage at the nonreducing ends of the oligosaccharides prosthetic groups are the best acceptor substrates. Isomers of N-acetyllactosamine with beta1 leads to 3 or beta1 leads to 6 glycosidic linkages are less than 1% as effective as acceptor substates as the beta1 leads to 4-linked isomer. Lactose (Galbeta1 leads to 4Glc) is also a poor acceptor, indicating the importance of the 2-acetamido group in the N-acetylglucosaminyl residues. The unnatural substrate beta-methyl-L-arabinopyrano-side, a five-carbon analog of beta-methyl-D-galactoside which contains no 6-hydroxyl, also acts as a poor acceptor of the transferase and the sialylated product has been partially characterized. Kinetic properties of the enzyme in the presence and absence of inhibitors suggest that the transferase has an equilibrium random order mechanism.

Animals↗
PubMed1977

Bacteriostatic effect of human milk and bovine colostrum on Escherichia coli: importance of bicarbonate.

At pH 7.4 and in the presence of NaHCO3, human milk and bovine colostrum inhibited the growth of Escherichia coli O111. Adding sufficient iron to saturate the iron-binding capacity of the lactoferrin present in the milk or colostrum prevented bacteriostasis. At pH 6.8 neither molk nor colostrum inhibited E. coli 0111. Adjusting the pH to 7.4 with NaHCO3 resulted in the development of bacteriostatic activity. Adjusting the pH to 7.4 with NaOH was ineffective. Dialyzed colostrum and milk inhibited bacterial growth at pH 6.8 in the absence of added NaHCO3; addition of citrate or iron abolished bacteriostasis. The chromatographic elution profile of tyrosyl-transfer ribonucleic acid (tRNA) from iron-replete E. coli differs significantly from that of tyrosyl-tRNA from iron-deficient organisms. Examination of the elution profile tyrosyl-tRNA from E. coli 0111 growing in colostrum without added NaHCO3 showed that such bacteria were fully replete in iron. The nature of the elution profile of tyrosyl-tRNA also showed that iron was freely available to the bacteria when citrate was added to dialyzed colostrum but not available in its absence, even at pH 6.8. Results support the idea that the bacteriostatic action of milk and colostrum, due to the combined action of antibody and lactoferrin, depends on the addition of bicarbonate to counteract the iron-mobilizing effect of the citrate normally present in these secretions.

Animals↗
PubMed1977

Purification of a sialyltransferase from bovine colostrum by affinity chromatography on CDP-agarose.

CDP-hexanolamine agarose was used as an affinity adsorbent to purify a CMP-N-acetylneuraminate: beta-D-galactosyl-glycoprotein N-acetylneuraminyltransferase (EC 2.4.99.1) from bovine colostrum. Upon binding of the enzyme to the adsorbent, elution is achieved either nonspecifically, with 0.5 to 1.0 M sodium chloride, or specifically, with CDP. A highly purified sialyltransferase is obtained with a specific activity 440,000 times that of whole colostrum. Fractionation of the purified enzyme by gel filtration gives two species with different molecular weights but equal specific activities toward asialo-alpha1-acid glycoprotein (26.0 to 28.0 micronmol/min/mg of enzyme). The molecular weights of these two forms are about 56,000 and 43,000 as judged by sodium doedcyl sulfate-gel electrophoresis, sedimentation equilibrium, and gel filtration. The catalytic properties of both forms have been examined (Paulson, J. C., Rearick, J. I., and Hill, R. L. (1977) J. Biol. Chem. 252, 2363-2371). It is concluded that the lower molecular weight form may be a partially degraded species of the enzyme of higher molecular weight.

Animals↗
PubMed1976

Affinity labeling of bovine colostrum galactosyltransferase with a uridine 5'-diphosphate derivative.

The dialdehyde produced by the periodate cleavage of the ribose moiety of uridine 5'-diphosphate (UDP) has been used as an affinity label for the UDP-galactose/UDP binding site of galactosyltransferase from bovine colostrum. This derivative causes progressive inactivation of galactosyltransferase at a rate dependent on its concentration, and under certain conditions is a competitive inhibitor with respect to UDP-galactose. The substrate UDP-galactose protects the enzyme from inactivation. The inactivation is also dependent on Mn2+ concentration in a range that implies that the binding of Mn2+ at site I is a prerequisite for the binding of the UDP derivative. The inactivation can be progressively reversed by nitrogenous bases, or stabilized by KBH4 reduction, which is consistent with the hypothesis that a Schiff base has formed with a lysine residue. Galactosyltransferase was inactivated with a [3H]UDP derivative and the predominant labeled peptide, from thermolysin digestion, isolated and characterized as: Ser-Gly-Lys-UDP.

Affinity Labels↗