bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phosphopeptides interacting with colloidal calcium phosphate isolated by tryptic hydrolysis of bovine casein micelles
Authors: Gagnaire Valerie , Pierre Alice , Molle Daniel , Leonil Joelle 
Published: June 2009

SummaryAfter extended tryptic hydrolysis of large bovine casein micelles, a mineral-rich peptide fraction was recovered by ultracentrifugation. Its mineral part contained 72% of the colloidal Ca and 49% of the colloidal Pioriginally present in the native micelle. Colloidal nitrogenous components were also present, amounting to 27% of the original N content. They contained most of the phosphopeptides and 82% of the micellar phosphoseryl residues. These tryptic peptides were characterized by reversed-phase HPLC on-line electrospray ion source–mass spectrometry analysis. Among the peptides produced 14 phosphopeptides were identified: αs2-CN(l–24), αs2-CN(1–21), αs1-CN(43–79), αs1-CN(35–79)7P, αs1-CN(35–79)8P, αs1-CN(37–79), αs1-CN(104–119), αs1-CN(104–124), β-CN(1–25), β-CN(1–28), β-CN(1–29), β-CN(30–97), β-CN(33–97) and β-CN(29–97). The proportion of the phosphopeptides interacting with colloidal calcium phosphate was correlated with their relative content of phosphoserine residues, since phosphopeptides containing more than four phos-phoserine residues were consistently present within this fraction. It also appeared that other types of peptides, some of them hydrophobic in nature, were also partly or completely present within the colloidal fraction, including αs1-CN(91–100), αs1-CN(152–193), αs1-CN(23–34), αs1-CN(125–193), αs1-CN(125–199), β-CN(177–209), β-CN( 184–209), β-CN(114–169) and β-CN(108–169). Their possible involvement in the micellar backbone is discussed.
Hyperkeratosis of the teat duct orifice in the dairy cow
Authors: Shearn Martin F. H. , Hillerton J. Eric 
Published: June 2009

SummaryTeat orifice hyperkeratosis, a commonly observed condition in dairy cows, has been considered a consequence of machine milking and the degree of hyperkeratosis may be increased by a poor milking system. A fully illustrated technique is described which uses a scoring system from 0 for a perfect orifice to 5 for an orifice significantly enlarged with extensively protruding fronds of teat duct keratin. A range of scores found in 25 commercial dairy herds is presented. The scores have been averaged for each cow and the markedly skewed distribution corrected by a square root transformation. This scoring procedure allows comparative measures of hyperkeratosis within and between herds. An 8-fold difference (0·17–1·31) in herd average score was found. Within all herds the score increased with lactational age of the animals and peaked, for any lactation, some 3–4 months post partum, declining as the animals dried off. There was no significant relationship between mean somatic cell count and degree of hyperkeratosis at the herd level. This implies that such chronic pathological changes are unlikely to be related to the level of intramammary infection. It appeared that some hyperkeratosis is an obvious and probably natural response to milking and occurs in a significant proportion of animals in all herds although often only to a slight degree. Much more hyperkeratosis may be a measure of the performance and management of the herd. The genetic influence is unknown. Higher yielding cows will score higher as they milk for longer, but generally high scores may reflect consistent and possibly considerable overmilking. Hyperkeratosis may be an indicator of the quality of management and show the level of attention being paid to the welfare of the herd.
Distribution of the anthelmintic drug albendazole and its major metabolites in ovine milk and milk products after a single oral dose
Authors: Liguoro Marco De , Longo Francesca , Brambilla Gianfranco , Cinquina Annalucia , Bocca Adriana , Lucisano Antonia 
Published: June 2009

SummaryThe distribution of albendazole (ABZ) and its main metabolites albendazole sulphoxide (ABZSO), albendazole sulphone (ABZS02) and albendazole 2-aminosulphone (NH2ABZSO2) were investigated in bulk milk and milk products after administration of a single oral dose of the drug (12·5 mg/kg) to 80 Laticauda sheep. An analytical method was developed for this investigation from an existing procedure used for the determination of these compounds in plasma and digesta samples. No traces of the parent compound or NH2ABZSO2were found in milk or milk products, with the exception of the milk collected 36 h after treatment in which 89 μg NH2ABZSO2/kg was detected. Results indicated that ABZ was rapidly oxidized to ABZSO and then to ABZSO2. These metabolites were found at high levels (1–4 mg/kg) in milk collected within 24 h after treatment. Products derived from such milk also contained high concentrations of the two oxidized metabolites, including up to 5 mg ABZSO/kg in Pecorino cheese. Only small quantities of these two metabolites were found in milk collected during the second day after treatment (range 50–500 μg/kg). They were no longer detectable in milk, collected during the third day after dosing, nor were they found in products made from such milk. These findings confirm that the two polar metabolites ABZSO and ABZSO2were efficiently excreted from the body. Considering that the established maximum residue limit for ovine milk is 100 μg/kg for ABZ plus its metabolites, our results confirmed the appropriateness of the currently prescribed withdrawal time (3 d) after the use of ABZ in lactating sheep. However, considerable levels of ABZSO were detected in milk collected within 24 h after treatment as well as in products and by-products derived from such milk. Owing to the known toxicity of the ABZSO, we stress the need for careful control to ensure adherence to the prescribed withdrawal time.
Cell cycle regulation of mammary epithelial cell detachment byStaphylococcus aureus
Authors: Zavizion Boris , Bramley Andrew J. , Politis Ioannis 
Published: June 2009

SummaryThe effect ofStaphylococcus aureuson detachment of bovine mammary epithelial cells in culture was examined. Mammary epithelial cells became detached from fresh monolayers following a 3 h incubation in the presence ofStaph. aureusM60. Two different procedures indicated that cell detachment coincided with the S-phase of the cell cycle. The roles of proteinases, toxins and Ca availability in inducing cell detachment were examined. Addition of the proteinase inhibitor phenyl-methylsulphonyl fluoride (1 mM) to the culture medium prevented cell detachment. Addition of a combination of purified staphylococcal proteinases XVI and XVII-B to the culture medium of mammary epithelial cells induced cell detachment in the absence ofStaph. aureus. Cell detachment may be caused by a staphylococcal proteinase. However, addition of Ca (10 mM) to the culture medium abolishedStaph. aureus-induced cell detachment, despite the fact that proteinase activity was still apparently present. Isogenic mutants ofStaph. aureusM60, expressing either ± or β toxins but not both, induced cell detachment, but to a lesser extent than the wild type. Thus, Ca and toxins play some role during cell detachment. Clones established from detached cells that were washed and replated showed the same susceptibility toStaph. aureus-induced cell detachment as the parental cells. This indicated that there is no subclone of mammary epithelial cells more sensitive to this effect.
316. Temperature control in the H.T.S.T. pasteurization process
Authors: Hall J. A. 
Published: June 2009

An investigation has been made into the accuracy and speed of response of temperature-measuring instruments suitable for use in the control of H.T.S.T. pasteurization. Thermocouples used in conjunction with a ‘d.c. amplifier’ recorder system are shown to be markedly superior to both vapour-pressure and mercury-in-steel thermometers. The accuracy of temperature measurement is about ±0.3°F. as against ±1°., while the lag constant is about 0.2 sec. as against about 3 sec. Response to small, rapid and transient changes of temperature is also shown to be greatly improved. The operation of control contacts by the thermocouple recorder was found to be reliable to well within the limit of accuracy of calibration, but the other types showed variations of the order of ±1°F., in addition to the uncertainties of calibration.The work described in this paper was undertaken at the request of the National Institute for Research in Dairying as part of the research programme of the National Physical Laboratory, and is published by permission of the Director of the Laboratory. The author wishes to acknowledge the help he has received from Dr A. T. R. Mattick and Miss E. R. Hiscox of the National Institute for Research in Dairying and from his colleagues Mr C. Wigley and Miss V. M. Leaver. Dr Mattick and Miss Hiscox supplied the experimental results given in the introduction, for the drafting of which they are largely responsible. Mr Wigley derived the equations used in computing the theoretical curves of Text-fig. 6 and Miss Leaver assisted with the observational work.
321. Reactions and properties of annatto as a cheese colour. Part II
Authors: Barnicoat C. R. 
Published: June 2009

Further work on the standardization of annatto for cheese colouring supports the author‘ earlier conclusions (l), viz.(1) The colouring power of annatto extracts in cheese can be estimated by their tinctorial power in dilute alkaline solution.(2) A simple tintometer of the ‘Limitester’ type is suitable for this work, a standard orange disk, or Lovibond yellow and orange glasses being used as the standard.
330. The technique of the bacteriological examination of dried milks
Authors: Higginbottom Constance 
Published: June 2009

1. A technique (B) for the reconstitution of both roller- and spray-dried milks is described which yields a liquid which is more satisfactory to handle, and gives clearer plates, higher counts and better replicates than the technique (A) at present recognized. The most important improvement in the new technique involves reconstitution, with a short holding period, at 50° C.2. For spray-dried full-cream milks the mean increases in the counts obtained by technique B as compared with technique A were: for 3 days at 37°C, slightly more than a three-fold increase; for 5 days at 30°C, slightly more than a two-fold increase; and for 3 days at 55° C. an 86% increase. The corresponding increases for spray-dried separated milk were for 3 days at 37°C, a two-fold increase, for 5 days at 30°C. a three- fold increase, and for 3 days at 55°C, a 23% increase. For roller-dried full-cream milk the increases were markedly smaller, i.e. 44, 41 and 29 %.3. After 6 months' storage spray-dried full-cream milks showed a slightly greater difference between counts by technique B than by technique A.4. A mean increase in plate count of about 10% was obtained by incubating plates for 5 instead of 3 days at 37° C. Although this increase was statistically significant, it is not considered that 5 days' incubation offers any practical advantage over 3 days' incubation.5. At 30°C. incubation for 5 days is essential. Thus the mean count after 5 days at 30° C. showed, for spray-dried powders, at least a two-fold increase over that at 3 days, though for roller-dried powders the increase was only 20 %. The percentage increase for spray-dried milks varied for individual samples and for samples from different plants.
Use of lyophilized skin for testing the bactericidal activity of teat disinfectants
Authors: Bramley A. John , Hogben Elizabeth M. 
Published: June 2009

SummaryThe bactericidal activities of various concentrations of 3 disinfectants commonly used for teat disinfection were compared in vitro using small discs of pig skin previously contaminated with Staphylococcus aureus. Solutions containing 40 g/1 Na hypochlorite, 25 or 50 g/1 chlorhexidine digluconate or iodophor containing 5 g/1 iodine were found to have equivalent or superior bactericidal activity to a solution containing 10 g/1 Na hypochlorite. This in vitro technique offers a convenient alternative to in vivo tests for teat disinfectants and with minor modifications could be applicable to the testing of skin antiseptics in general.
Physicochemical transformation of milk components and release of foot-and-mouth disease virus
Authors: Blackwell John H. , McKercher Peter D. , Kosikowski Frank V. , Carmichael Leland E. , Gorewit Ronald C. 
Published: June 2009

SummaryPossible mechanisms for protective roles of milk components on footand-mouth disease virus present in the milk of infected cows were examined. Light scattering bands collected from Ficoll-sucrose gradient fractions of skim-milk contained membrane-limited structures but these were non-infectious for bovine kidney cells, lnfectivity titres in buttermilk higher than those of the original cream or butter suggested association of virus with milk fat globules. Increased infectivity titres in skim-milk after treatment with SDS suggested release of virus particles from dissociated casein micelle subunits. Chelating agents, de-emulsifying agents and trypsin, which alter the structure of the individual milk components casein, lipid and milk fat globule membrane were without effect on infectivity titres.
Phagocytosis ofStaphylococcus aureusby bovine mammary gland macrophages and intracellular protection from antibiotic actionin vitroandin vivo
Authors: Craven Neil , Anderson James C. 
Published: June 2009

SummaryMacrophages isolated from the involuted bovine mammary gland were culturedin vitro. Phagocytosis of opsonizedStaphylococcus aureusoccurred rapidly, but intracellular killing of bacteria was slow. Many intracellular staphylococci survived for up to 4 d exposure to extracellular cloxacillin and emerged from within the macrophages to multiply extracellularly when the antibiotic was inactivated. Rifampicin was significantly more efficient than cloxacillin in killing intracellularS. aureusafter 18 h incubation, but it too failed to sterilize the cultures within 3 d. Staphylococci, which had remained viable within macrophages during 20 h incubation with extracellular cloxacillin, showed an increased sensitivity to dilute lysostaphin on subsequent exposure. A 3 d course of intramammary therapy with cloxacillin, commencing simultaneously with an infecting inoculum of ∼108colony forming units (c.f.u.)S. aureus, apparently eliminated the infection from one quarter of the udders of each of three lactating cows, but bacteria were re-isolated from two cows after a delay of several days. However, when other quarters of the same cows were infected with ∼108c.f.u.S. aureuswhich had been phagocytosed by autologous mammary macrophages, similar simultaneous antibiotic therapy failed to affect these infections. Thein vitroandin vivofindings indicate the significance of intracellular survival ofS. aureusas a factor contributing to failure of antibiotic therapy.
Projection of lactation milk yield from part records in crossbred dairy cows
Authors: Yadav Sutej B. S. , Sharma Jai S. , Dutta Om P. 
Published: June 2009

SummaryFirst lactation records of a total of 242 Jersey (JH), Brown Swiss (BH) and Holstein-Friesian (FH) halfbreeds from Hariana cows were studied for projecting 300 d milk yield from 12,14,16,18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38 and 40 weeks’ milk yield. The correlation coefficients between 300 d milk yield and part records ranged from 0·84 to 0·9 in the JH, 0·80 to 0·90 in the BH and 0·72 to 0·86 in the FH groups. Prediction equations and standard errors of estimation for prediction of 300 d milk yield for an individual animal are presented. It is suggested that part records up to 16, 22 and 22 weeks may be used for projecting 300 d yield with sufficient accuracy in the JH, BH and FH groups respectively.
Fixation of bovine casein micelles for chromatography on controlled pore glass
Authors: Anderson Malcolm , Griffin Mary C. A. , Moore Carolyn 
Published: June 2009

SummaryGlutaraldehyde was used to fix the size distribution of casein micelles in skim milk before their fractionation by permeation chromatography on controlled pore glass. The effect of fixation was assessed by comparing the size and absorption profile for column fractions obtained from samples which were fixed before fractionation with those of unfixed samples and of samples that were fixed only after completion of chromatography. Micelle size was determined by photon correlation spectroscopy. Column profiles were obtained from absorption measurements at 340 nm and after pronase digestion at 280 nm to determine relative protein concentration. For comparative purposes the elution profile was divided into 4 peak areas, of which I-III contained most of the casein micelles, and IV consisted of the smallest micelles, soluble casein and whey protein. Average micelle size was unaltered by fixation but was larger in fractions from prefixed skim milk than those from unfixed samples. Fixation increased the absorbance readings but the elution profile at 340 nm for peak areas I-III was essentially the same for unfixed fractions and those obtained when fixation was applied after chromatography. However, areas I-III accounted for a much larger proportion of the total profile area when the latter procedure was followed. Total profile area increased with fixation time and temperature but this did not affect the elution profile. The results indicate that fixation with glutaraldehyde does not induce artefactual changes in casein micelle size.
Effects of colloidal calcium phosphate content and free calcium ion concentration in the milk serum on the dissociation of bovine casein micelles
Authors: Holt Carl , Davies D. Thomas , Law Andrew J. R. 
Published: June 2009

SummaryThe strength of binding of the individual caseins and the nature of the bonding within bovine casein micelles were examined through dissociation of the micelles by dialysis of skim milk either against phosphate-free buffers containing 3 or 6 mm-CaCl2, or against buffers that were nearly saturated with respect to micellar calcium phosphate, but which had a free Ca2+ concentration in the range 0·4–5·9 mm. Dissociation was followed by ultracentrifuging the dialysed milks and determining the partition of the total and the individual caseins between the pellet and serum. During dialysis against the phosphate-free buffers both colloidal Ca and Pi in the milks decreased and about 30 % of the Pi could be removed without significant casein dissociation. With further loss of Pi, however, increasing dissociation occurred and the proportions of the individual caseins retained in the casein pellet were in the order αs2- > αs1- > β- ≈ κ-casein. Dialysis against the calcium phosphate buffers resulted in no loss of colloidal Pi but colloidal Ca increased with the free Ca2+ concentration of the buffer. Little change in the casein partition occurred in the presence of more than 1 mm free Ca2+, but serum casein increased markedly at lower levels, and the strength of binding of the individual caseins in the pelleted casein was in the order αs2-> αs1- > β- > κ-casein. In both types of buffer, dissociation is considered to occur through the breaking of linkages between the caseins and inorganic constituents. Analysis of the amino acids in a calcium phosphate-rich material obtained after exhaustive proteolytic digestion of casein micelles suggests that these linkages involve the phosphate centres of the caseins.
Improved milking characteristics of teatcups fitted with non-return valves
Authors: Andrews R. Jeffrey , Mein Graeme A. , Brown Murray R. 
Published: June 2009

SummaryThe milking characteristics of conventional clusters were compared with individual teatcups or clusters fitted with valves in the short milk tubes without external air admission to the liners. Individual teatcups fitted with non-return valves had peak milk flow rates 13% higher than conventional teatcups. A daily cross-over experiment involving 36 cows compared clusters fitted with non-return valves to conventional clusters. Valved clusters milked 18% faster, showed significantly better teatcup stability and 3% higher machine milk yields, but 48% higher strip yields were recorded. Clusters with non-return valves were difficult to remove after milking because the valve closed when the vacuum supply was shut off, thereby maintaining the vacuum level under the teats. When the nominal plant vacuum level for teatcups with non-return valves was reduced by 10 kPa to compensate for the higher effective milking vacuum level, the valved teatcups had peak flow rates 20% lower than the conventional teatcups. Clusters fitted with a modified valve, which allowed some reverse flow when closed (a ‘leaky’ valve), milked significantly faster than conventional clusters, had 33% lower strip yields and were easy to remove after milking.
Production of concentratedStreptococcus salivariussubsp.thermophilusby coupling continuous fermentation and ultrafiltration
Authors: Prigent Claudine , Corre Christian , Boyaval Patrick 
Published: June 2009

SummaryContinuous production of concentrated cells ofStreptococcus salivariussubsp.thermophiluswas achieved in a continuous stirred tank reactor coupled with an ultrafiltration module. A cellular productivity nine times higher than that obtained by conventional methods was observed. The viability of the cells produced was as satisfactory as that obtained by classical culture, but an increase in latency time and a slight decrease in acidification rate during downstream tests in milk were observed. Specific lactic acid productivity decreased as biomass increased. This process produced concentrated starters and lactic acid which could be purified by a downstream processing such as electrodialysis.
Lack of effect of epidermal growth factor treatment in late-pregnant ewes on subsequent lactation
Authors: Gow Christine B. , Singleton Debbi J. , Silvapulle Mervyn J. , Moore G. Philip M. 
Published: June 2009

SummaryTwin-bearing ewes were treated with epidermal growth factor (EGF) to determine its effect on mammogenesis and resultant milk production and composition. The EGF was infused intravenously at a dose rate of O5 mg/d in 300 ml saline between days 117 and 139 of gestation; control animals received placebo infusions of saline. All animals then received continuous infusions of 300 ml/d saline on days 139–144. Following parturition 1–5 d later, ewes were milked by hand for 10 d and thereafter were machine-milked until day 16 of lactation. At this level of treatment, EGF was not detected in the circulation during infusion and feed intake was not affected. All ewes gave birth to healthy twin lambs. There were no effects of EGF on birth weights of lambs, live weights of ewes or lengths of gestation. An EGF immunoreactive material was detected in the mammary secretions of control ewes at a mean concentration of 2 μg/l on day 1 of lactation. Two ewes had detectable levels on day 2, but none was found in the milk thereafter. In the EGF-infused group, concentrations of EGF in colostrum were ñ 10 times higher than in the control ewes on day 1 of lactation and EGF was detected in mammary secretions on day 2 but not in subsequent milk samples. A range of 0·3–0·5% of the EGF infused appeared in mammary secretions over the first 2 d of lactation. No other differences were observed for colostrum composition, subsequent milk yield or composition between the two groups of ewes indicating that mammary gland development and function were unaffected. The levels of EGF observed in the mammary secretions of treated and control ewes indicate that the mammary glands accumulate and store EGF in the pre partum period.