Academic literature on the topic 'Milk proteins'
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Journal articles on the topic "Milk proteins"
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CHANG, M. K., and H. ZHANG. "Carbonated Milk: Proteins." Journal of Food Science 57, no. 4 (July 1992): 880–82. http://dx.doi.org/10.1111/j.1365-2621.1992.tb14314.x.
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SETO, Yasuyuki. "Bovine Milk Proteins." Oleoscience 23, no. 8 (2023): 415–21. http://dx.doi.org/10.5650/oleoscience.23.415.
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Ye, Aiqian, Skelte G. Anema, and Harjinder Singh. "Changes in the surface protein of the fat globules during homogenization and heat treatment of concentrated milk." Journal of Dairy Research 75, no. 3 (July 14, 2008): 347–53. http://dx.doi.org/10.1017/s0022029908003464.
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The changes in milk fat globules and fat globule surface proteins of both low-preheated and high-preheated concentrated milks, which were homogenized at low or high pressure, were examined. The average fat globule size decreased with increasing homogenization pressure. The total surface protein (mg m−2) of concentrated milk increased after homogenization, the extent of the increase being dependent on the temperature and the pressure of homogenization, as well as on the preheat treatment. The concentrates obtained from high-preheated milks had higher surface protein concentration than the concentrates obtained from low-preheated milks after homogenization. Concentrated milks heat treated at 79°C either before or after homogenization had greater amounts of fat globule surface protein than concentrated milks heat treated at 50 or 65°C. This was attributed to the association of whey protein with the native MFGM (milk fat globule membrane) proteins and the adsorbed skim milk proteins. Also, at the same homogenization temperature and pressure, the amount of whey protein on the fat globule surface of the concentrated milk that was heated after homogenization was greater than that of the concentrated milk that was heated before homogenization. The amounts of the major native MFGM proteins did not change during homogenization, indicating that the skim milk proteins did not displace the native MFGM proteins but adsorbed on to the newly formed surface.
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Horne, David S., and Jeffrey Leaver. "Milk proteins on surfaces." Food Hydrocolloids 9, no. 2 (June 1995): 91–95. http://dx.doi.org/10.1016/s0268-005x(09)80270-1.
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Wal, Jean-Michel. "Cow's milk proteins/allergens." Annals of Allergy, Asthma & Immunology 89, no. 6 (December 2002): 3–10. http://dx.doi.org/10.1016/s1081-1206(10)62115-1.
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DONNELLY, WILLIAM J., and RAJ K. MEHRA. "Fractionation of milk proteins." Biochemical Society Transactions 18, no. 2 (April 1, 1990): 238–40. http://dx.doi.org/10.1042/bst0180238.
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Ye, A., S. G. Anema, and H. Singh. "High-Pressure–Induced Interactions Between Milk Fat Globule Membrane Proteins and Skim Milk Proteins in Whole Milk." Journal of Dairy Science 87, no. 12 (December 2004): 4013–22. http://dx.doi.org/10.3168/jds.s0022-0302(04)73542-0.
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Turpeinen, Anu, Hanna Kautiainen, Marja-Leena Tikkanen, Timo Sibakov, Olli Tossavainen, and Eveliina Myllyluoma. "Mild protein hydrolysation of lactose-free milk further reduces milk-related gastrointestinal symptoms." Journal of Dairy Research 83, no. 2 (April 1, 2016): 256–60. http://dx.doi.org/10.1017/s0022029916000066.
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Gastrointestinal symptoms associated with milk are common. Besides lactose, milk proteins may cause symptoms in sensitive individuals. We have developed a method for mild enzymatic hydrolysation of milk proteins and studied the effects of hydrolysed milk on gastrointestinal symptoms in adults with a self-diagnosed sensitive stomach. In a double blind, randomised placebo-controlled study, 97 subjects consumed protein-hydrolysed lactose-free milk or commercially available lactose-free milk for 10 d. Frequency of gastrointestinal symptoms during the study period was reported and a symptom score was calculated. Rumbling and flatulence decreased significantly in the hydrolysed milk group (P < 0·05). Also, the total symptom score was lower in subjects who consumed hydrolysed milk (P < 0·05). No difference between groups was seen in abdominal pain (P = 0·47) or bloating (P = 0·076). The results suggest that mild enzymatic protein hydrolysation may decrease gastrointestinal symptoms in adults with a sensitive stomach.
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Montagne, Paul, Marie Louise Cuillière, Claire Molé, Marie Christine Béné, and Gilbert Faure. "Immunological and Nutritional Composition of Human Milk in Relation to Prematurity and Mothers' Parity During the First 2 Weeks of Lactation." Journal of Pediatric Gastroenterology and Nutrition 29, no. 1 (July 1999): 75–80. http://dx.doi.org/10.1002/j.1536-4801.1999.tb02365.x.
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ABSTRACTBackground:To investigate the effect of prematurity and parity on the dynamics of the major immunologic and nutritional proteins of human milk over the first 2 weeks of lactation.Methods:Microparticle‐enhanced nephelometric immunoassays were developed for the quantification of α‐lactalbumin, β‐casein, serum albumin, lactoferrin, and lysozyme in human milk. These components, immunoglobulin A, and total proteins were assayed in 368 individual samples collected from 74 mothers.Results:The dynamics of the major immunologic and nutritional proteins in early lactation presented similar patterns in preterm and term human milks. In comparison with term milk, preterm milk was globally characterized by higher concentrations of immune proteins and lower concentrations of nutritive proteins. These differences were increased by the degree of prematurity, which, however, influenced the absolute and relative protein concentrations differently, depending on the stage of lactation. The protein composition of term milk was similar, whatever the mother's parity. Conversely, the influence of prematurity on the levels of milk proteins during the first days of lactation was even greater in primiparous mothers.Conclusions:This precise description of the composition of preterm and term milk, regarding the main nutritional and immunologic proteins, confirms the influence of both prematurity and parity on milk components and demonstrates the combined effect of these two conditions.
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Kinsella, John E., Patrick F. Fox, and Louis B. Rockland. "Water sorption by proteins: Milk and whey proteins." C R C Critical Reviews in Food Science and Nutrition 24, no. 2 (January 1986): 91–139. http://dx.doi.org/10.1080/10408398609527434.
Full textDissertations / Theses on the topic "Milk proteins"
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Billakanti, Jaganmohan. "Extraction of High-Value Minor Proteins from Milk." Thesis, University of Canterbury. Chemical and Process Engineering, 2009. http://hdl.handle.net/10092/3843.
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Various methods for extraction and analysis of high value minor proteins (lactoferrin, lactoperoxidase and immunoglobulins) directly from raw milk were explored. Extraction, purification and analysis of high-value minor proteins directly from milk without pre-treatment are major challenges for dairy industry, largely due to the complexity of milk and the presence of colloidal solids (casein micelles and milk fat globules). To overcome some of these challenges, this work focused on three main objectives: 1) characterization of cryogel monolith chromatography for purification of lactoferrin (LF) and lactoperoxidase (LP) directly from raw milk in single step, 2) identification and characterization of Protein A Mimetic affinity ligands for purification of immunoglobulins (Igs) from milk and 3) development and validation of a surface plasmon resonance method for simultaneous quantification of five whey proteins in multiple samples.
Results portrayed the possibility of 40–50 column volumes of various milk samples (whole milk, skim milk and acid whey) to pass through a 5 mL cryogel monolith chromatography column at 525 cm hr⁻¹ without exceeding its pressure limits if the processing temperature is maintained around 35–37°C. Ideally, this should be the milk secretion temperature. The dynamic binding capacity obtained for the cryogel matrix (2.1 mg mL⁻¹) was similar to that of the binding capacity (2.01 mg mL⁻¹) at equilibrium with 0.1 mg mL⁻¹ of lactoferrin in the feed samples. Lactoferrin and lactoperoxidase was selectively bound to the cryogel column with trivial leakage in flowthrough fractions. Lactoferrin was recovered from elution fractions with a yield of 85% and a purity of 90%. These results, together with the ease of manufacture, low cost and versatile surface chemistry of cryogels suggest that they may be a good alternative to packed-bed chromatography for direct capture of proteins from milk, provided that the binding capacity can be increased.
A Protein A Mimetic (PAM) hexapeptide (HWRGWV) peptide ligand that binds to the Fc portion of antibody molecules was explored for affinity purification of immunoglobulins from milk. The peptide has the ability to purify IgG from various milk and whey samples with a purity of greater than 85% in single step. More than 90% bound IgG was recovered with 0.2 M acetate buffer at pH 4.0 and total column regeneration was successfully achieved by 2.0 M guanidine-HCl. At 9.0 mg mL⁻¹ of IgG feed concentration, an equilibrium binding capacity of 21.7 mg mL⁻¹ and dynamic binding capacity of approximately 12.0 mg mL⁻¹ of resin was obtained. Recoveries and yields of IgG were significantly influenced by the feed IgG concentration. PAM hexamer ligand also contributed a significant amount of cross-reactivity with casein, glycomacropeptides and β-lactoglobulin proteins, however majority of these proteins were recovered in the regeneration step, except β-lactoglobulin, which co-eluted with IgG. Higher IgG concentration in feed vastly reduced the amount of cross-reactivity whilst increasing the recoveries and purities in the final product. PAM affinity ligands also showed interactions towards other classes of bovine immunoglobulins. These findings established the possibility of using PAM hexamer peptide as an alternative to conventional Protein A/G affinity chromatography for the isolation of Igs from milk in single step process.
A surface plasmon resonance (SPR) method was developed for simultaneous, quantitative determination of commercially important whey proteins in raw and processed milk samples, whey fractions and various milk-derived products, with six samples per assay. Immobilized antibody stability and reproducibility of analyses were studied over time for 25 independent runs (n=300), giving a relative standard deviation (RSD) of <4%. Immobilized antibodies showed negligible non-specific interactions (<2–4 SPR response units (RU)) and no cross-reactivity towards other milk components (<1 RU). Regeneration of immobilised antibodies with glycine at pH 1.75 was determined to be optimal for maintaining the SPR response between samples. This method compared and validated well with reversed phase high performance liquid chromatography (RP-HPLC) and standard enzyme-linked immunosorbent assays (ELISA).
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Brooksbank, Dawn Victoria. "Adsorption of milk proteins onto charged surfaces." Thesis, University of Glasgow, 1993. http://theses.gla.ac.uk/8390/.
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The research in this thesis deals with the influence of charge on the adsorption of milk proteins to surfaces. A variety of charged surfaces were used including negatively charged and zwitterionic liposomes prepared from phosphatidylglycerol and phosphatidylcholine respectively and positively and negatively charged polystyrene latices. Adsorption was determined by measuring the increase in the hydrodynamic radius of the particles by photon correlation spectroscopy and also by solution depletion techniques. In some instances, electrophoretic mobility measurements were also used in order to determine changes in the surface charge of the particle as a result of protein adsorption. The ionic strength and pH of the buffer were found to be important in the adsorption of protein to liposomes. In the absence of NaCl, adsorption did not occur. At low pH values, addition of both k-casein and B-Iactoglobulin to negatively charged liposomes caused very large increases in size presumably as a result of aggregation. At pH6.2, protein layer thicknesses on the negatively charged liposomes were significantly greater than on the zwitterionic ones due to charge repulsion between the negatively charged surface and the negatively charged regions of the proteins. Removal of the negatively charged phosphate groups which form a cluster in the hydrophilic region of B-casein resulted in a reduction in the thickness of the adsorbed protein layer on the negatively charged liposome but did not have any effect on the thickness on the zwitterionic surface. The thickness of adsorbed layers of as1-, k-, and B-casein and B-lactoglobulin on the phosphatidylcholine liposomes were all very similar at around 6nm. Addition of as1-casein to the negatively charged liposomes appeared to cause aggregation as a result of protein molecules bridging between liposomes. Attempts to determine the fraction of added protein which bound to the surface of the liposomes were unsuccessful and therefore, the binding of native, dephosphorylated and methyl-esterified l3-casein to small, monodisperse, positively and negatively charged polystyrene latices was studied. As with the liposomes, the thickness of the adsorbed B-casein layer was greater on the negatively charged surface. Removal of the phosphate groups from the protein decreased the layer thickness by about 4nm on the negatively charged surface but had relatively little effect on the thickness on the positively charged surface, once again showing the effect of charge interactions. As with dephosphorylation, methylation also reduces the net negative charge of the protein, but by a different mechanism. This also resulted in a reduction in the thickness of the adsorbed protein layers but only after a significant proportion of the free carboxyl groups had been esterified. Thus methylation of 35 % of these groups had relatively little effect on the thickness of the layer on the positively charged latex and no effect on the negatively charged, but esterification of a further 9% (equivalent to two residues) caused a substantial decrease in thickness on both surfaces. These changes are believed to result from alterations in both the charge and hydrophilicity of particular regions of the B-casein molecule. Bridging was found to occur when low levels of native or modified B-casein were added to the positively charged latex. Protein loading was found to range from 2.5 to 5.5mg m-2 depending on the nature of the protein and the charge on the surface. The thickness of adsorbed native and dephosphorylated B-casein layers on the negatively charged latex was found to be influenced by the presence of calcium and increasing ionic strength. Increasing levels of either calcium ions or NaCI in the medium resulted in a very pronounced decrease in the thickness of pre-adsorbed phosphorylated B-casein layers. The changes in dephosphorylated protein layers were less pronounced. The results are discussed in terms of the proposed loop-and-train configuration of the B-casein at the surface of the latex. The influence of protein phenotype and the extent of glycosylation on the adsorption of k-casein was also determined. The more highly glycosylated protein molecules, which also had a higher net negative charge, formed thicker layers on the negatively charged surface. Again, layer thicknesses were less on the positively charged surface, but for each x-cn phenotype glycosylation increased the thickness, presumably as a result of the increased hydrophilicity of the protein. k-Casein A, which has one more negative charge than the B phenotype, was found to give a slightly thicker layer on the negatively charged latex. Under certain conditions, adsorbed k-casein could be cleaved by the enzyme chymosin as shown by the reduction in the size of the coated latex.
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Dong, Chin. "Existence of silent variants of milk proteins." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=56657.
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Genetic variants of milk proteins are the result of mutation causing substitutions or deletions of amino acids in the peptides. Certain variants are closely associated with milk production, milk composition and milk qualities such as heat stability and cheesemaking properties. All of the milk protein variants known so far, have been detected by electrophoresis because mutations which have occurred gave rise to changes in net charges. "Silent" variants involve amino acid substitutions which are not accompanied by charge differences and hence would not be identified by electrophoresis. The aim of this project was to search for silent variants of $ alpha sb{ rm s1}$-casein, $ beta$-casein and $ kappa$-casein by application of reversed-phase HPLC for the identification of mutants causing changes in hydrophobicities of peptides.Whole casein from 281 Holstein and Ayrshire milk samples were fractionated by DEAE-cellulose ion-exchange chromatography, using an FPLC system. The pure forms of major caseins ($ alpha sb{ rm s1}$-casein, $ beta$-casein and $ kappa$-casein) were hydrolysed by trypsin and the digests obtained therefrom were resolved by reversed-phase HPLC. Comparison of peptide profiles within the same electrophoretic variant of homozygous caseins indicated that 24 out of 264 $ alpha sb{ rm s1}$-casein BB, 9 out of 57 $ beta$-casein A$ sp1$A$ sp1$, 5 out of 55 $ beta$-casein A$ sp2$A$ sp2$ and 8 out of 188 $ kappa$-casein AA could be classified as potential silent variants.
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Giambra, Isabella Jasmin [Verfasser]. "Ovine milk proteins : DNA, mRNA, and protein analyses and their associations to milk performance traits / Isabella Jasmin Giambra." Gießen : Universitätsbibliothek, 2011. http://d-nb.info/1063111137/34.
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Sumual, Maria Fransisca. "Fractionation and characterization of proteins from coconut milk." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22813.
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Centrifugation of coconut milk resulted in cream, skim milk, and insoluble solids. Proteins were isolated from skim milk by the addition of acid, with or without heating. The separation and isolation gave the following coconut protein preparations: coconut milk, coconut skim milk, insoluble solids, acid precipitate, and acid-heat precipitate.Trypsin inhibitory activity (TIA) of the coconut protein preparations was relatively low while tryptic digestibility of the isolated proteins was considerably lower than those of the coconut milk and skim milk, the digestibility of coconut protein preparations was lower than that of casein. In general, the emulsifying and farming properties of coconut protein preparations were lower than casein. The insoluble solids showed the highest viscosity when compared with the coconut protein preparations. In contrast to the whey protein concentrate (WPC), the apparent strain of gels from the acid precipitate increased as the pH increased. The gelation properties at pH 3 of the insoluble solids were better than WPC.
The estimated molecular weight by size-exclusion chromatography of coconut protein preparations gave 3 fractions with MW ranging from 6850 Da to 229402 Da. In native PAGE, coconut proteins were separated into at least 3 subunits and under SDS-denatured conditions, the major protein subunits showed MW of 54531 Da and 25008 Da, respectively. RP-HPLC separation of coconut milk, acid precipitate, and acid-heat precipitate gave 3 fractions containing several species of MW ranging between 35574 Da to 51209 Da when analyzed by mass spectometry.
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Narayanaswamy, Venkatachalam. "A Study of the Interactions Between Milk Proteins and Soy Proteins." DigitalCommons@USU, 1997. https://digitalcommons.usu.edu/etd/5422.
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This research investigates the protein interactions that occur when soy protein is added to milk and subjected to renneting or heating. Milk was fortified with 20% soy protein and enzymic coagulation studied at 35°C at various pH's and CaCl2 levels. The first part deals with the interaction between milk and soy proteins during rennet-induced milk coagulation. The first goal was to determine how soy proteins affected milk coagulation. The effects of native versus heat-denatured soy proteins on rennet coagulation time and curd firmness were compared. lmmunogold labeling along with transmission electron microscopy was used to identify and localfze soy proteins in coagulated milk. Partitioning of ß-conglycinin and glycinin, the two main soy protein fractions, between cheese and whey was determined by electrophoresis.
Soy proteins affected milk coagulation to the greatest extent at pH 6.6. Both heat-denatured and native soy proteins increased rennet coagulation time. Only heat-denatured soy proteins affected final curd firmness. Most of ß-conglycinin was lost in whey, whereas glycinin was retained in curd.
Soy proteins existed in the curd as aggregates that were less electron dense than casein micelles. At pH 6.6, heat-denatured soy proteins were fibrous and adhered to the surfaces of casein micelle, preventing direct micelle-micelle contact. This would delay aggregation rate and decrease curd firmness by decreasing the number and strength of links between casein micelles. Native soy proteins did not bind to the casein micelles but rather were physically trapped within curd. Their effect of delaying aggregation is thought to be a function of their binding of calcium. Adding CaCl2 or lowering the pH to 6.3 or 6.0 helped restore coagulation properties.
The second goal was to determine what heat-induced interaction occurs between milk and soy proteins, specifically between κ-casein and glycinin. Both κ-casein and glycinin are heat labile and form insoluble aggregates when heated. When glycinin and κ-casein were heated together, some acidic polypeptides of glycinin crosslinked with κ-casein via disulfide linkages. However, when disulfide linkage was prevented by adding ß-mercaptoethanol , non-covalent interactions between κ-casein and both acidic and basic polypeptides of glycinin occurred that prevented the heat precipitation of glycinin. This non-covalent interaction between glycinin polypeptides and κ-casein may explain why the heat-treated soy proteins became attached to the surfaces of casein micelles during rennet coagulation of milk.
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Yu, Feiran. "Physicochemical Modifications of Milk Fat Globule Membrane Proteins During Temperature Processing of Milk." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1534770720065921.
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Luimes, Paul Hendrik. "An examination of endocrine and nutrient controls of milk protein production /." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=38499.
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The control of milk protein production was investigated utilising two different approaches. The first model is one of intravenous infusion of atropine. Atropine, which decreases milk protein yield, has been theorised to act either by decreasing blood somatotropin (ST) concentration or by decreasing blood amino acid (AA) concentration. Thus, the first experiment was designed to test which mechanism, or both, is responsible for the effects on milk protein yield. Five lactating dairy cows were assigned to the following treatments which were administered intravenously: Saline (CONT), atropine (ATR), ATR + ST, ATR + AAs, and ATR + ST + AAs. Atropine treatment failed to decrease plasma ST concentration but did decrease plasma alpha-amino nitrogen concentration. Atropine treatment decreased milk protein yield but neither ST, AAs, nor ST + AAs were able to maintain milk protein yield at the CONT level when infused with ATR. It is clear that the treatments tested are not directly responsible for the decrease in milk protein yield due to ATR. Therefore, neither ST, AAs, nor ST + AAs appear to have direct control of milk protein production. Plasma insulin (INS) concentration was decreased and plasma IGF-I concentration was not decreased by ATR treatment. Insulin, therefore, presents itself as a candidate for direct control over milk protein synthesis. The second model is one of monitoring endocrine response to abomasal infusion of AAs mimicking the profile of milk protein with selective deletion of certain AAs. Six lactating dairy cows were subjected to the following treatments: Saline (negative control, NC), AAs (positive control, PC), PC minus methionine (PC-Met), PC minus lysine (PC-Lys), PC minus histidine (PC-His), and PC minus the branched-chain AAs (PC-BCAAs). All endocrine factors studied (ST, INS, glucagon & IGF-I) were affected by treatment. Plasma IGF-I concentration responded similarly, except for the PC-Met treatment, to milk protein yield (Weekes and Cant, 200
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Steventon, Anthony James. "Thermal aggregation of whey proteins." Thesis, University of Cambridge, 1993. https://www.repository.cam.ac.uk/handle/1810/251549.
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Walsh, Marie K. "Measurement of Proteins in Milk and Dairy Products." DigitalCommons@USU, 1988. https://digitalcommons.usu.edu/etd/5360.
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The purpose of this study was to develop a short, easy procedure to measure five major proteins in milk and to detect concentrations of added protein to dairy products. Combinations of casein or whey protein with nonfat-dry milk were made with concentration ratios from 0:10 to 10:0. Similar mixtures of defatted goat milk with defatted cow milk were prepared. Samples were hydrolyzed in 6 N HCl at 145°C for 4 h and analyzed for amino acid composition. Multiple regression equations were derived to estimate the relative content of whey protein or casein added to nonfat-dry milk and goat milk added to cow milk employing amino acid profiles of whey protein, casein, nonfat-dry milk, goat milk and cow milk. Correlation coefficient values were all greater than .99. Measuring individual concentrations of milk proteins required separating casein and why proteins by reverse phase high performance liquid chromatography on a C3 column. αs-, β-, and κ-casein were separated after dissociating casein micelles with mercaptoethanol and urea. A 40:60 to 0:100 gradient of .15 M sodium chloride/triethylamine (pH 2.5) and 40% acetonitrile was used. Whey proteins, α-lactalbumin and β-lactoglobulin were separated with a 95:5 to 0:100 gradient of .15 M sodium chloride (pH 2.4) and acetonitrile. Eluted proteins were collected from the column, analyzed for purity by electrophoresis, and hydrolyzed in 6 N HCl at 145°C for 4 h. Purified proteins and mixtures of purified proteins were analyzed for amino acid composition. Estimates of individual protein concentrations in mixtures were made by solving simultaneous equations based on amino acid composition using a tektronix 4052 computer.
Books on the topic "Milk proteins"
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Barth, C. A., and E. Schlimme, eds. Milk Proteins. Heidelberg: Steinkopff, 1989. http://dx.doi.org/10.1007/978-3-642-85373-9.
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Newberry, M. P. Milk proteins in baked goods. Christchurch, N.Z: New Zealand Institute for Crop & Food Research, 1994.
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A, Atkinson Stephanie, and Lönnerdal Bo 1938-, eds. Protein and non-protein nitrogen in human milk. Boca Raton, Fla: CRC Press, 1989.
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Federation, International Dairy, and IDF Symposium (2nd : 1994 : Århus, Denmark), eds. Milk protein: Definition & standardization. Brussels, Belgium: International Dairy Federation, 1995.
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International Congress on Milk Proteins (1984 Luxemburg). Milk proteins '84: Proceedings of the International Congress on Milk Proteins, Luxemburg, 7-11 May 1984. Edited by Galesloot T. E and Tinbergen B. J. Wageningen, the Netherlands: Pudoc, 1985.
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1961-, Castro Fidel O., and Jänne Juhani, eds. Mammary gland transgenesis: Therapeutic protein production. Berlin: Springer, 1998.
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Federation, International Dairy, and IDF Symposium on Protein Definition (1st : 1993 : Minneapolis, Minn.), eds. Protein definition: Proceedings of the First IDF Symposium held in Minneapolis, USA, October 1993. Brussels, Belgium: International Dairy Federation, 1994.
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Symposium on Industrial Aspects of Milk Proteins (1987 Fermoy, Co. Cork). Industrial aspects of milk proteins: Proceedings ... atMoorepark Research Centre, 27 and 28 October 1987. Fermoy: Moorepark Research Centre, 1987.
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IDF Seminar ( 1997 Palmerston North, N.Z.). Milk protein polymorphism: Proceedings of the IDF Seminar held in Palmerston North, New Zealand, February 1997. Brussels: International Dairy Federation, 1997.
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Phelan, Paul. An N.M.R. Study of Cyanylated - Lactoglobulins and Thiocyanate Model Compounds. Dublin: University College Dublin, 1998.
Find full textBook chapters on the topic "Milk proteins"
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Gay, J. "Research Funding by the EEC." In Milk Proteins, 1–4. Heidelberg: Steinkopff, 1989. http://dx.doi.org/10.1007/978-3-642-85373-9_1.
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de Waard, H., and P. L. M. Reyven. "The Effects of Quantity and Type of Dietary Protein on the Rehabilitation after a Period of Energetic Undernourishment." In Milk Proteins, 83. Heidelberg: Steinkopff, 1989. http://dx.doi.org/10.1007/978-3-642-85373-9_10.
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Lönnerdal, B. "Milk Proteins and Metabolic Requirements of Trace Elements, Minerals, and Vitamins." In Milk Proteins, 87–96. Heidelberg: Steinkopff, 1989. http://dx.doi.org/10.1007/978-3-642-85373-9_11.
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Davidsson, L., Å. Cederblad, B. Lönnerdal, and B. Sandström. "Manganese Absorption from Human Milk, Cow Milk, and Infant Formulas." In Milk Proteins, 97–99. Heidelberg: Steinkopff, 1989. http://dx.doi.org/10.1007/978-3-642-85373-9_12.
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Gislason, J., B. Jones, B. Lönnerdal, and L. Hambraeus. "Intrinsic Labelling of Iron in Milk." In Milk Proteins, 100–102. Heidelberg: Steinkopff, 1989. http://dx.doi.org/10.1007/978-3-642-85373-9_13.
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Schmitz, M., H. Hagemeister, Iris Görtler, J. G. Bindels, and C. A. Barth. "Does Bovine Lactoferrin Resist Absorption in the Small Intestine of Neonatal and Adult Pigs?" In Milk Proteins, 103–4. Heidelberg: Steinkopff, 1989. http://dx.doi.org/10.1007/978-3-642-85373-9_14.
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Schulz-Lell, G., H. D. Oldigs, K. Dörner, and J. Schaub. "Can Lactoferrin Supplementation Improve the Availability of Iron from Milk?" In Milk Proteins, 105–7. Heidelberg: Steinkopff, 1989. http://dx.doi.org/10.1007/978-3-642-85373-9_15.
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Schoppe, I., C. A. Barth, and H. Hagemeister. "The Nutritive Value of Bovine Lactoferrin." In Milk Proteins, 108–9. Heidelberg: Steinkopff, 1989. http://dx.doi.org/10.1007/978-3-642-85373-9_16.
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Ribadeau-Dumas, B. "Structure and Variability of Milk Proteins." In Milk Proteins, 112–23. Heidelberg: Steinkopff, 1989. http://dx.doi.org/10.1007/978-3-642-85373-9_17.
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Simons, J. Paul. "Modification of Milk by Gene Transfer." In Milk Proteins, 124–32. Heidelberg: Steinkopff, 1989. http://dx.doi.org/10.1007/978-3-642-85373-9_18.
Full textConference papers on the topic "Milk proteins"
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Milovanović, Vesna, Miloš Petrović, Vladimir Kurćubić, Marko Petković, Nemanja Miletić, and Igor Đurović. "COMPARISON OF COW’S MILK WITH PLANT-BASED MILK ALTERNATIVES: SELECTED CHEMICAL AND PHYSICAL ANALYSIS." In 1st INTERNATIONAL SYMPOSIUM ON BIOTECHNOLOGY. University of Kragujevac, Faculty of Agronomy, 2023. http://dx.doi.org/10.46793/sbt28.517m.
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The aim of this paper is to make a chemical and physical comparison of cow's milk with plant-based milk alternatives. Selected chemical and physical parameters of animal milk (raw and pasteurized cow’s milk) and plant based milk (almond and soy milk) were done. The titratable acidity, pH, conductivity, viscosity and density were measured by using standardized techniques. Additional parameters such as proteins, fat, (solids-not-fat) SNF, and lactose were determined by milk analyser and compared. The results showed that plant-based milks contain low values of proteins, fat, SNF and significantly lower acidity in comparison with cow's milk.
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Tirtom, Sena, and Aslı Akpınar. "Dairy Protein vs. Plant Protein and Their Consumer Perception." In 7th International Students Science Congress. Izmir International guest Students Association, 2023. http://dx.doi.org/10.52460/issc.2023.026.
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Proteins are crucial macronutrient for human health. Animal, dairy, and some plant proteins are considered high-quality proteins that provide health and metabolic benefits based on the digestible levels of essential amino acids they contain. Animal protein is rich in many essential amino acids, but excessive animal protein intake greatly increases fat intake. Therefore, due to the improvement in people's living standards and increase in protein intake, the animal protein supply is not sufficient to meet the increasing demand of people. Technologically, milk proteins are the most important component of milk due to their unique properties that allow milk to be converted into a wide range of products such as cheese or yoghurt quite easily. It is widely accepted that dairy products are excellent sources of highly digestible essential amino acids. Nowadays, plant protein is preferred because has advantages such as it is an abundant source, cheap, easy to obtain, preferred by special consumer groups such as vegan/vegetarian, does not contain cholesterol and preventing diseases. In the last decades, the increasing interest of both producers and consumers in plant proteins and the decrease in animal protein intake and inclination to plant protein intake with the innovations in the markets emphasize the importance of these alternative sources. In this review, information is given about the importance of milk proteins and plant proteins and the role they play in consumer preference is mentioned.
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Gutov, N. "STUDY OF FRACTIONAL COMPOSITION OF PROTEINS OF MILK-PROTEIN CONCENTRATES." In I International Congress “The Latest Achievements of Medicine, Healthcare, and Health-Saving Technologies”. Kemerovo State University, 2023. http://dx.doi.org/10.21603/-i-ic-36.
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Purpose: to study the fractions of casein proteins and whey proteins with reference to their molecular weight values. Consider the nature of microfiltration and diafiltration processes actively accepted in the separation of casein proteins from whey proteins. Describe the process of removing pathogenic microflora from defatted mo-lock using ceramic membranes.
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Savić, Željko, Aleksandar Čukić, Ljiljana Anđušić, and Božidar Milošević. "Changes of total proteins during maturation period of Sjenica cheese." In Zbornik radova 26. medunarodni kongres Mediteranske federacije za zdravlje i produkciju preživara - FeMeSPRum. Poljoprivredni fakultet Novi Sad, 2024. http://dx.doi.org/10.5937/femesprumns24028s.
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Proteins are one of the most important milk quality parameters and the course of coagulation, composition and technological properties of cheese curd depend on them. Proteins form the basis of the structure of Curds and cheese in which milk fat is incorporated, and represent the substrate for enzymes during the ripening of Sjenica cheese. Sjenica cheese is originally produced on the Sjenica-Pester plateau, from whole, fresh, sheep and cow milk, and belongs to the group of white cheeses in brine. Considering the importance of proteins, this research aimed to determine the protein content after cheese making, and to monitor changes after 30, 60, 120, 180 days of ripening, and the extent of degradation using electrophoresis. The results of the research showed that the total protein content was the highest in Sjenica cheese after 30 days of ripening (15.54%), and in Sjenica type cheese after 60 days of ripening (16.55%). After 30, i.e. 60, 120, 180 days of ripening, there is a slight decrease in total protein in both cheeses, as a result of the transfer of soluble nitrogen from the cheese to the ripening brine. After 180 days, the total protein content was 12.78% for Sjenicki and 13.92% for Sjenicki type cheese. Electrophoretic studies showed that protein degradation occurred mostly during the first 60 days of ripening, after that the protein fractions appear in traces as diffuse zones.
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Moldovan, Irina, and Ecaterina Stasii. "P80 Case report: allergy to milk proteins." In Faculty of Paediatrics of the Royal College of Physicians of Ireland, 9th Europaediatrics Congress, 13–15 June, Dublin, Ireland 2019. BMJ Publishing Group Ltd and Royal College of Paediatrics and Child Health, 2019. http://dx.doi.org/10.1136/archdischild-2019-epa.435.
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Dallas, David. "Digestive Survival of Milk Proteins and Release of Antimicrobial and Immunomodulatory Milk Peptides." In Virtual 2021 AOCS Annual Meeting & Expo. American Oil Chemists’ Society (AOCS), 2021. http://dx.doi.org/10.21748/am21.435.
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Kolbatskaya, S. S., E. R. Gazizullina, E. L. Gerasimova, and A. V. Ivanova. "Influence of milk proteins on coffee antioxidant properties." In THE 2ND INTERNATIONAL CONFERENCE ON PHYSICAL INSTRUMENTATION AND ADVANCED MATERIALS 2019. AIP Publishing, 2020. http://dx.doi.org/10.1063/5.0032217.
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Alatalo, Diana, and Fatemeh Hassanipour. "An Experimental Study on Human Milk Viscosity." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-68761.
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Human milk is a complex fluid suspension of many ingredients — such as fats, proteins, lactose, and minerals — that differs greatly from bovine and other mammalian milks. The rheological properties of human milk impact its flow inside the breast and when fed through artificial feeding methods. Past research concerning the flow characteristics of human milk is extremely limited and does not account for milks non-Newtonian behavior. In order to produce an accurate model of milk flow in the human breast, experimental work was performed on human milk donated by eight mothers at different stages of lactogenesis II. The results of this small study reveal the complexity of human milk flow characteristics and the challenges involved with modeling its flow, especially at low shear rates. Within the human breast, shear rates vary greatly from as low as 12 s−1 to as high as 2.5 × 1016 s−1 depending on the ductal system geometry and flow rate. For researchers involved in experimentation, the environmental conditions, handling methods, and age of milk are extremely important and must be reported if the data is to be of any value. Further experimentation is required to fully understand the mechanisms behind the time-dependence behavior of human milk.
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Kalugina, O. I., K. A. Shlyapina, E. R. Baranova, and S. A. Simon. "CHEESE AS PREVENTION OF PROTEIN-ENERGY INSUFFICIENCY." In I International Congress “The Latest Achievements of Medicine, Healthcare, and Health-Saving Technologies”. Kemerovo State University, 2023. http://dx.doi.org/10.21603/-i-ic-48.
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Protein-energy depletion (PEW) is the depletion of protein/energy reserves observed in the most advanced stages of chronic kidney disease (CKD). PEW is widespread among patients on chronic dialysis and is associated with adverse clinical outcomes, high morbidity/mortality rates and increased healthcare costs. Cheeses are characterized by a significant content of proteins, milk fat, as well as minerals. Cheese proteins are better absorbed in the human body, compared with dairy. Extractive elements of cheeses have a positive effect on the digestive glands, increase appetite. The nutrients contained in cheese are absorbed by the body almost completely.
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Rotariu, Lia Sanda, Georgeta-Sofia Popescu, Adrian Varsandan, Manuel-Ovidiu Amzoiu, and Florina Radu. "CHEMICAL AND RHEOLOGICAL CHARACTERIZATION OF HOMEMADE SOY MILK." In 23rd SGEM International Multidisciplinary Scientific GeoConference 2023. STEF92 Technology, 2023. http://dx.doi.org/10.5593/sgem2023v/6.2/s25.09.
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The objective of this work was to evaluate the physical, chemical and rhelogical characteristics of vegetable milk of soybean (soymilk homemade prepared, and some types of soymilk purchased from Romanian supermarkets). Soymilk is an alternative to dairy products and it has long been a traditional drink in China, Japan and other parts of Asia. The soybean (Glycine max) is the most important bean in the world, providing a wide range of vegetable proteins. Soybean is an important source of many bioactive compounds, which are important for the health benefits conferred. Soymilk is a colloidal solution obtained in the form of water extract from swollen and ground soybeans. Soymilk is rich in protein, calcium and has no saturated fat. It is low in calories, being the perfect alternative for people with lactose intolerance. This kind of drink is especially used for vegetarian people, people with lactose intolerance, and those who hold religious fasting. The soymilk has been prepared from analyzed grains and then some chemical and physical characteristics of milk have been assessed. We investigated moisture and total dry content substance (TDC), total mineral content- ash content, macronutrients content (fat, protein and carbohydrates content) for soybeans and soymilk samples. For soymilk, we established total solid content (brix grade), pH, sensory evaluation, and some rheological characteristics.
Reports on the topic "Milk proteins"
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Barash, Itamar, and Robert E. Rhoads. Translational Mechanisms that Govern Milk Protein Levels and Composition. United States Department of Agriculture, November 2004. http://dx.doi.org/10.32747/2004.7586474.bard.
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Original objectives: The long term objective of the project is to achieve higher content of protein in the milk of ruminants by modulating the translational machinery in the mammary gland. The first specific aim of the BARD proposal was to characterize responsiveness of various experimental systems to combination of lactogenic hormones and amino acids with particular emphasis on discrimination between the control of total protein synthesis and milk protein synthesis. Based on the results, we planned to proceed by characterizing the stage of protein synthesis in which the stimulation by lactogenic hormones and amino acid occur and finally we proposed to identify which components of the translation machinery are modified. Background to the topic: Milk protein is the most valuable component in milk, both for direct human consumption and for manufacturing cheese and other protein-based products. Attempts to augment protein content by the traditional methods of genetic selection and improved nutritional regimes have failed. The proposal was based on recent results suggesting that the limiting factor for augmenting protein synthesis in the bovine mammary gland is the efficiency of converting amino acids to milk proteins. Major conclusions, solutions, achievements: Insulin and prolactin synergistically stimulate â-casein mRNA translation by cytoplasmatic polyadenylation. The interaction between insulin and prolactin was demonstrated two decades ago as crucial for milk-protein synthesis, but the molecular mechanisms involved were not elucidated. We found in differentiated CID 9 mouse mammary epithelial cells line that insulin and prolactin synergistically increases the rate of milk protein mRNA translation. We focused on â-casein, the major milk protein, and found that the increase in â-casein mRNA translation was reflected in a shift to larger polysomes, indicating an effect on translational initiation. Inhibitors of the PI3K, mTOR, and MAPK pathways blocked insulin-stimulated total protein and â-casein synthesis but not the synergistic stimulation. Conversely, cordycepin, a polyadenylation inhibitor, abolished synergistic stimulation of protein synthesis without affecting insulin-stimulated translation. The poly(A) tract of â-casein mRNA progressively increased over 30 min of treatment with insulin plus prolactin. The 3’-untranslated region of â-casein mRNA was found to contain a cytoplasmic polyadenylation element (CPE), and in reporter constructs, this was sufficient for the translational enhancement and mRNA-specific polyadenylation. Furthermore, insulin and prolactin stimulated phosphorylation of cytoplasmic polyadenylation element binding protein (CPEB) but did not increase cytoplasmic polyadenylation.
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Barash, Itamar, and Robert Rhoads. Translational Mechanisms Governing Milk Protein Levels and Composition. United States Department of Agriculture, 2006. http://dx.doi.org/10.32747/2006.7696526.bard.
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Original objectives: The long-term goal of the research is to achieve higher protein content in the milk of ruminants by modulating the translational apparatus of the mammary gland genetically, nutritionally, or pharmacologically. The short-term objectives are to obtain a better understanding of 1) the role of amino acids (AA) as regulators of translation in bovine and mouse mammary epithelial cells and 2) the mechanism responsible for the synergistic enhancement of milk-protein mRNA polyadenylation by insulin and prolactin. Background of the topic: In many cell types and tissues, individual AA affect a signaling pathway which parallels the insulin pathway to modulate rates and levels of protein synthesis. Diverse nutritional and hormonal conditions are funneled to mTOR, a multidomain serine/threonine kinase that regulates a number of components in the initiation and elongation stages of translation. The mechanism by which AA signal mTOR is largely unknown. During the current grant period, we have studied the effect of essential AA on mechanisms involved in protein synthesis in differentiated mammary epithelial cells cultured under lactogenic conditions. We also studied lactogenic hormone regulation of milk protein synthesis in differentiated mammary epithelial cells. In the first BARD grant (2000-03), we discovered a novel mechanism for mRNA-specific hormone-regulated translation, namely, that the combination of insulin plus prolactin causes cytoplasmic polyadenylation of milk protein mRNAs, which leads to their efficient translation. In the current BARD grant, we have pursued the signaling pathways of this novel hormone action. Major conclusions/solutions/achievements: The positive and negative signaling from AA to the mTOR pathway, combined with modulation of insulin sensitization, mediates the synthesis rates of total and specific milk proteins in mammary epithelial cells. The current in vitro study revealed cryptic negative effects of Lys, His, and Thr on cellular mechanisms regulating translation initiation and protein synthesis in mammary epithelial cells that could not be detected by conventional in vivo analyses. We also showed that a signaling pathway involving Jak2 and Stat5, previously shown to lead from the prolactin receptor to transcription of milk protein genes, is also used for cytoplasmic polyadenylation of milk protein mRNAs, thereby stabilizing these mRNAs and activating them for translation. Implications: In vivo, plasma AA levels are affected by nutritional and hormonal effects as well as by conditions of exercise and stress. The amplitude in plasma AA levels resembles that applied in the current in vitro study. Thus, by changing plasma AA levels in the epithelial cell microenvironment or by sensitizing the mTOR pathway to their presence, it should be possible to modulate the rate of milk protein synthesis. Furthermore, knowledge that phosphorylation of Stat5 is required for enhanced milk protein synthesis in response to lactogenic opens the possibility for pharmacologic approaches to increase the phosphorylation of Stat5 and, thereby, milk protein production.
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Delwiche, Michael, Boaz Zion, Robert BonDurant, Judith Rishpon, Ephraim Maltz, and Miriam Rosenberg. Biosensors for On-Line Measurement of Reproductive Hormones and Milk Proteins to Improve Dairy Herd Management. United States Department of Agriculture, February 2001. http://dx.doi.org/10.32747/2001.7573998.bard.
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The original objectives of this research project were to: (1) develop immunoassays, photometric sensors, and electrochemical sensors for real-time measurement of progesterone and estradiol in milk, (2) develop biosensors for measurement of caseins in milk, and (3) integrate and adapt these sensor technologies to create an automated electronic sensing system for operation in dairy parlors during milking. The overall direction of research was not changed, although the work was expanded to include other milk components such as urea and lactose. A second generation biosensor for on-line measurement of bovine progesterone was designed and tested. Anti-progesterone antibody was coated on small disks of nitrocellulose membrane, which were inserted in the reaction chamber prior to testing, and a real-time assay was developed. The biosensor was designed using micropumps and valves under computer control, and assayed fluid volumes on the order of 1 ml. An automated sampler was designed to draw a test volume of milk from the long milk tube using a 4-way pinch valve. The system could execute a measurement cycle in about 10 min. Progesterone could be measured at concentrations low enough to distinguish luteal-phase from follicular-phase cows. The potential of the sensor to detect actual ovulatory events was compared with standard methods of estrus detection, including human observation and an activity monitor. The biosensor correctly identified all ovulatory events during its testperiod, but the variability at low progesterone concentrations triggered some false positives. Direct on-line measurement and intelligent interpretation of reproductive hormone profiles offers the potential for substantial improvement in reproductive management. A simple potentiometric method for measurement of milk protein was developed and tested. The method was based on the fact that proteins bind iodine. When proteins are added to a solution of the redox couple iodine/iodide (I-I2), the concentration of free iodine is changed and, as a consequence, the potential between two electrodes immersed in the solution is changed. The method worked well with analytical casein solutions and accurately measured concentrations of analytical caseins added to fresh milk. When tested with actual milk samples, the correlation between the sensor readings and the reference lab results (of both total proteins and casein content) was inferior to that of analytical casein. A number of different technologies were explored for the analysis of milk urea, and a manometric technique was selected for the final design. In the new sensor, urea in the sample was hydrolyzed to ammonium and carbonate by the enzyme urease, and subsequent shaking of the sample with citric acid in a sealed cell allowed urea to be estimated as a change in partial pressure of carbon dioxide. The pressure change in the cell was measured with a miniature piezoresistive pressure sensor, and effects of background dissolved gases and vapor pressures were corrected for by repeating the measurement of pressure developed in the sample without the addition of urease. Results were accurate in the physiological range of milk, the assay was faster than the typical milking period, and no toxic reagents were required. A sampling device was designed and built to passively draw milk from the long milk tube in the parlor. An electrochemical sensor for lactose was developed starting with a three-cascaded-enzyme sensor, evolving into two enzymes and CO2[Fe (CN)6] as a mediator, and then into a microflow injection system using poly-osmium modified screen-printed electrodes. The sensor was designed to serve multiple milking positions, using a manifold valve, a sampling valve, and two pumps. Disposable screen-printed electrodes with enzymatic membranes were used. The sensor was optimized for electrode coating components, flow rate, pH, and sample size, and the results correlated well (r2= 0.967) with known lactose concentrations.
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Bobe, Gerd, A. E. Gene Freeman, Gary L. Lindberg, and Donald C. Beitz. Milk Protein Genotypes Explain Variation of Milk Protein Composition. Ames (Iowa): Iowa State University, January 2004. http://dx.doi.org/10.31274/ans_air-180814-614.
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McGuire, Mark A., Amichai Arieli, Israel Bruckental, and Dale E. Bauman. Increasing Mammary Protein Synthesis through Endocrine and Nutritional Signals. United States Department of Agriculture, January 2001. http://dx.doi.org/10.32747/2001.7574338.bard.
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Objectives To determine endocrine factors that regulate the partitioning of amino acids by the mammary gland. To evaluate dietary flow and supply of energy and amino acids and their effects on milk protein synthesis and endocrine status. To use primary cultures of cow mammary epithelial cells to examine the role of specific factors on the rates and pattern of milk protein synthesis. Milk protein is an increasingly valuable component of milk but little is known regarding the specific hormonal and nutritional factors controlling milk protein synthesis. The research conducted for this project has determined that milk protein synthesis has the potential to be enhanced much greater than previously believed. Increases of over 25% in milk protein percent and yield were detected in studies utilizing abomasal infusion of casein and a hyperinsulinemic-euglycemic clamp. Thus, it appears that insulin, either directly or indirectly, can elicit a substantial increase in milk protein synthesis if additional amino acids are supplied. For additional amino acids, casein provided the best response even though substantial decreases in branched chain amino acids occur when the insulin clamp is utilized. Branched chain amino acids alone are incapable of supporting the enhanced milk protein output. The mammary gland can vary both blood flow and extraction efficiency of amino acids to support protein synthesis. A mammary culture system was used to demonstrate specific endocrine effects on milk protein synthesis. Insulin-like growth factor-I when substituted for insulin was able to enhance casein and a-lactalbumin mRNA. This suggests that insulin is a indirect regulator of milk protein synthesis working through the IGF system to control mammary production of casein and a-lactalbumin. Principal component analysis determined that carbohydrate had the greatest effect on milk protein yield with protein supply only having minor effects. Work in cattle determined that the site of digestion of starch did not affect milk composition alone but the degradability of starch and protein in the rumen can interact to alter milk yield. Cows fed diets with a high degree of rumen undegradability failed to specifically enhance milk protein but produced greater milk yield with similar composition. The mammary gland has an amazing ability to produce protein of great value. Research conducted here has demonstrated the unprecedented potential of the metabolic machinery in the mammary gland. Insulin, probably signaling the mammary gland through the IGF system is a key regulator that must be combined with adequate nutrition in order for maximum response.
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Sordillo, Lorraine, Don Wojchowski, Gary Perdew, Arthur Saran, and Gabriel Leitner. Identification of Staphylococcus aureaus Virulence Factors Associated with Bovine Mastitis. United States Department of Agriculture, February 2001. http://dx.doi.org/10.32747/2001.7574340.bard.
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Staphylococcus aureus is a major cause of mastitis in dairy cattle. The organism is able to adhere to and penetrate mammary epithelium, forming deep seated abscesses that result in chronic infections. This study was based on the observation that certain genotypes of S. aureus are isolated more frequently from field cases of bovine mastitis than others and the most prevalent genotypes of S. aureus have an increased ability to resist neutrophil phagocytosis and killing compared to the rare variants. It was hypothesized that these predominating genotypes differentially express virulence factors that allow them to overcome or suppress essential host defense mechanisms and successfully colonize mammary parenchyma. The overall objective of this study was to determine the mechanisms by which predominating S. aureus genotypes were able to resist mammary gland defense mechanisms. The following specific aims were accomplished to address the overall objectives of this project: 1. Analyze and compare cell surface and secreted protein profiles of common and rare S. aureus genotypes isolated from field cases of bovine mastitis. 2. Purify and sequence selectively synthesized proteins unique to the most prevalent genotypes of S. aureus . 3. Determine the in vitro effects of isolated proteins on essential host defense mechanisms. Results from each specific aim showed that these redominating genotypes differentially express factors that may allow them to overcome or suppress essential host defense mechanisms and successfully colonize mammary parenchyma. Using complementary approaches, both the US and Israeli teams identified differentially expressed S. aureus factors that were positively correlated with virulence as determined by the ability to modify host immune cell responses and increase disease pathogenesis. Several candidate virulence factors have ben identified at both the molecular (US team) and protein (Israeli team) levels. Components of the phosphotransferase system were shown to be differentially expressed in prevalent strains of S. aureus and to modify the growth potential of these strains in a milk microenvironment. Evidence provided by both the Israeli and US teams also demonstrated a potential role of Staphylococcal enterotoxins in the pathogenesis of mastitis. Certain enterotoxins were shown to directly affect neutrophil bactericidal activities which can profoundly affect the establishment of new intramammary infections. Other evidence suggests that S. aureus superantigens can suppress mammary defenses by enhancing lymphoid suppressor cell activity. Collectively, these data suggest that unique factors are associated with predominating S. aureus genotypes that can affect in vitro and in vivo virulence as related to the pathogenesis of bovine mastitis. The potential development of a subunit mastitis vaccine which incorporates only relevant antigenic determinants has not been investigated in depth. Experiments outlined in this proposal has identified putative virulence factors which contribute to the pathogenesis of S. aureus mastitis and which may be used to formulate an efficacious subunit mastitis vaccine. Results from these studies may lead to the development of new methods to prevent this costly disease, providing a viable alternative to less effective mastitis control procedures based on chemotherapy.
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Splitter, Gary A., Menachem Banai, and Jerome S. Harms. Brucella second messenger coordinates stages of infection. United States Department of Agriculture, January 2011. http://dx.doi.org/10.32747/2011.7699864.bard.
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Aim 1: To determine levels of this second messenger in: a) B. melitensiscyclic-dimericguanosinemonophosphate-regulating mutants (BMEI1448, BMEI1453, and BMEI1520), and b) B. melitensis16M (wild type) and mutant infections of macrophages and immune competent mice. (US lab primary) Aim 2: To determine proteomic differences between Brucelladeletion mutants BMEI1453 (high cyclic-dimericguanosinemonophosphate, chronic persistent state) and BMEI1520 (low cyclicdimericguanosinemonophosphate, acute virulent state) compared to wild type B. melitensisto identify the role of this second messenger in establishing the two polar states of brucellosis. (US lab primary with synergistic assistance from the Israel lab Aim 3: Determine the level of Brucellacyclic-dimericguanosinemonophosphate and transcriptional expression from naturally infected placenta. (Israel lab primary with synergistic assistance from the US lab). B. Background Brucellaspecies are Gram-negative, facultative intracellular bacterial pathogens that cause brucellosis, the most prevalent zoonosis worldwide. Brucellosis is characterized by increased abortion, weak offspring, and decreased milk production in animals. Humans are infected with Brucellaby consuming contaminated milk products or via inhalation of aerosolized bacteria from occupational hazards. Chronic human infections can result in complications such as liver damage, orchitis, endocarditis, and arthritis. Brucellaspp. have the ability to infect both professional and non-professional phagocytes. Because of this, Brucellaencounter varied environments both throughout the body and within a cell and must adapt accordingly. To date, few virulence factors have been identified in B. melitensisand even less is known about how these virulence factors are regulated. Subsequently, little is known about how Brucellaadapt to its rapidly changing environments, and how it alternates between acute and chronic virulence. Our studies suggest that decreased concentrations of cyclic dimericguanosinemonophosphate (c-di-GMP) lead to an acute virulent state and increased concentrations of c-di-GMP lead to persistent, chronic state of B. melitensisin a mouse model of infection. We hypothesize that B. melitensisuses c-di-GMP to transition from the chronic state of an infected host to the acute, virulent stage of infection in the placenta where the bacteria prepare to infect a new host. Studies on environmental pathogens such as Vibrio choleraeand Pseudomonas aeruginosasupport a mechanism where changes in c-di-GMP levels cause the bacterium to alternate between virulent and chronic states. Little work exists on understanding the role of c-di-GMP in dangerous intracellular pathogens, like Brucellathat is a frequent pathogen in Israeli domestic animals and U.S. elk and bison. Brucellamust carefully regulate virulence factors during infection of a host to ensure proper expression at appropriate times in response to host cues. Recently, the novel secondary signaling molecule c-di-GMP has been identified as a major component of bacterial regulation and we have identified c-di-GMP as an important signaling factor in B. melitensishost adaptation. C. Major conclusions, solutions, achievements 1. The B. melitensis1453 deletion mutant has increased c-di-GMP, while the 1520 deletion mutant has decreased c-di-GMP. 2. Both mutants grow similarly in in vitro cultures; however, the 1453 mutant has a microcolony phenotype both in vitro and in vivo 3. The 1453 mutant has increased crystal violet staining suggesting biofilm formation. 4. Scanning electron microscopy revealed an abnormal coccus appearance with in increased cell area. 5. Proteomic analysis revealed the 1453 mutant possessed increased production of proteins involved in cell wall processes, cell division, and the Type IV secretion system, and a decrease in proteins involved in amino acid transport/metabolism, carbohydrate metabolism, fatty acid production, and iron acquisition suggesting less preparedness for intracellular survival. 6. RNAseq analysis of bone marrow derived macrophages infected with the mutants revealed the host immune response is greatly reduced with the 1453 mutant infection. These findings support that microlocalization of proteins involved in c-di-GMP homeostasis serve a second messenger to B. melitensisregulating functions of the bacteria during infection of the host.
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Sengupta-Gopalan, Champa, Shmuel Galili, and Rachel Amir. Improving Methionine Content in Transgenic Forage Legumes. United States Department of Agriculture, February 2001. http://dx.doi.org/10.32747/2001.7580671.bard.
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Leguminous forage crops are high in proteins but deficient in S- amino acids. It has been shown that both wool quality and milk production can be limited by the post-ruminal supply of sulfur-containing amino acids. Efforts to use conventional plant breeding and cell selection techniques to increase the S-amino acid content of alfalfa have met with little success. With the objective to increase the S-amino acid content of forage legumes, the goal of this project was to co- express the methionine rich zein genes from corn along with a gene for a key enzyme in methionine biosynthesis, aspartate kinase(AK). The zeins are seed storage proteins from corn and are groupec into four distinct classes based on their amino acid sequence homologies. The b-zein (15kd) and the 6zein (10kD and 18kD) have proportionately high levels of methionine (10%, 22% and 28%, respectively). Initial studies from our lab had shown that while the 15kD zein accumulated to high levels in vegetative tissues of transgenic tobacco the l0kD zein did not. However, co-expression of the 10kD zein with the 15kD zein genes in tobacco showed stabilization of the 10kD zein and the co-localization of the 10kD and 15kD zein proteins in unique ER derived protein bodies. AK is the key enzyme for producing carbon skeletons for all amino acids of the aspartate family including methionine. It is, however, regulated by end-product feedback inhibition. The specific objectives of this proposal were: i. to co-express the 15kD zein with the 10/18kD zein genes in alfalfa in order to enhance the level of accumulation of the 10/18kD zein; ii. to increase methionine pools by expressing a feedback insensitive AK gene in transformants co-expressing the 15kD and 10/18kD zein genes. The Israeli partners were successful in expressing the AK gene in alfalfa which resulted in an increase in free and bound threonine but not in methionine (Galili et al., 2000). Since our target was to increase methionine pools, we changed our second objective to replace the AK gene with the gene for cystathionine gamma synthase (CGS) in the co-expression studies. The first methionine specific reaction is catalyzed by CGS. An additional objective was to develop a transformation system for Berseem clover, and to introduce the appropriate gene constructs into it with the goal of improving their methionine content. Genes for the 15kD zein along with the genes for either the 10kD or 18kD zein have been introduced into the same alfalfa plant both by sexual crosses and by re-transformation. Analysis of these zein co-expressors have shown that both the IOkD and 18kD zein levels go up 5 to 10 fold when co-expressed with the 15kD zein (Bagga et al., MS in preparation). Incubation of the leaves of transgenic alfalfa co-expressing the 15kD and 10kD zein genes, in the rumen of cows have shown that the zein proteins are stable in the rumen. To increase the level of zein accumulation in transgenic alfalfa different promoters have been used to drive the zein genes in alfalfa and we have concluded that the CaMV 35S promoter is superior to the other strong leaf -specific promoters. By feeding callus tissue of alfalfa plants co-expressing the 15kD and 10kD zein genes with methionine and its precursors, we have shown that the zein levels could be significantly enhanced by increasing the methionine pools. We have now introduced the CGS gene (from Arabidopsis; kindly provided to us by Dr. Leustek), into the 15kD zein transformants and experiments are in progress to check if the expression of the CGS gene indeed increases the level of zein accumulation in alfalfa. We were not successful in developing a transformation protocol for Berseem clover.
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Huber, John Tal, Joshuah Miron, Brent Theurer, Israel Bruckental, and Spencer Swingle. Influence of Ruminal Starch Degradability on Performance of High Producing Dairy Cows. United States Department of Agriculture, January 1994. http://dx.doi.org/10.32747/1994.7568748.bard.
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This research project entitled "Influence of Ruminal Starch Degradability on Performance of High Producing Dairy Cows" had the following objectives: a) Determine effects of feeding varying amounts of ruminally degradable starch (RDS) on efficiency of milk and milk protein production; and 2) Investigate digestive and metabolic mechanisms relating to lactation responses to diets varying in ruminal and total starch degradability. Four lactation studies with high producing cows were conducted in which steam-flaked (~ 75% RDS) was compared with dry-rolled sorghum (~ 50% RDS) grain. All studies demonstrated increased efficiency of conversion of feed to milk (FCM/DMI) and milk protein as amount of RDS in the diet increased by feeding steam-flaked sorghum. As RDS in diets increased, either by increased steam-flaked sorghum, grinding of sorghum, or increasing the proportion of wheat to sorghum, so also did ruminal and total tract digestibilities of starch and neutral-detergent soluble (NDS) carbohydrate. Despite other research by these two groups of workers showing increased non-ammonia N (NAN) flowing from the rumen to the duodenum with higher RDS, only one of the present studies showed such an effect. Post-absorptive studies showed that higher dietary RDS resulted in greater urea recycling, more propionate absorption, a tendency for greater output of glucose by the liver, and increased uptake of alpha-amino nitrogen by the mammary gland. These studies have shown that processing sorghum grain through steam-flaking increases RDS and results in greater yields and efficiency of production of milk and milk protein in high producing dairy cows.
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Barash, Itamar, J. Mina Bissell, Alexander Faerman, and Moshe Shani. Modification of Milk Composition via Transgenesis: The Role of the Extracellular Matrix in Regulating Transgene Expression. United States Department of Agriculture, July 1995. http://dx.doi.org/10.32747/1995.7570558.bard.
Full textAbstract:
Altering milk composition via transgenesis depends on three main factors. (1) The availability of an efficient regulatory sequences for targeting transgene(s) to the mammary gland; (2) a reliable in vitro model to test the expression of transgenes prior to their introduction to the animal genome; and (3) better understanding of the major factors which determine the rate of gene expression and protein synthesis. The current studies provide the necessary means and knowledge to alter milk protein composition via transgenesis. The following specific goals were achieved: a: Identifying regulatory regions in the b-lactoglobulin (BLG) gene and the cross-talk between elements which enabled us to construct an efficient vector for the expression of desirable cDNA's in the mammary gland. b: The establishment of a sheep mammary cell line that serves as a model for the analysis of endogenous and exogenous milk protein synthesis in the mammary gland of livestock. c: An accurate comparison of the potency of the 5' regulatory sequences from the BLG and whey acidic protein (WAP) promoters in directing the expression of human serum albumin (HSA) to the mammary gland in vitro and in vivo. In this study we have also shown that sequences within the coding region may determine a specific pattern of expression for the transgene, distinct from that of the native milk protein genes. d: Characterizing the dominant role of ECM in transgene expression in mammary epithelial cells. e: Further characterization of the BCE-1 enhancer element in the promoter of the b-casein gene as a binding site for the c/EBP-b and Stat5. Identifying its interaction with chromatin and its up regulation by inhibitors of histone deacetylation. f: Identifying a mechanism of translational control as a mediator for the synergistic effect of insulin and prolactin on protein synthesis in the mammary gland.