scholarly journals Centrifugation does not remove bacteria from the fat fraction of human milk

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lisa F. Stinson ◽  
Jie Ma ◽  
Alethea Rea ◽  
Michael Dymock ◽  
Donna T. Geddes
Keyword(s):  
Human Milk ◽  
High Speed ◽  
Bovine Milk ◽  
Skim Milk ◽  
Bacterial Dna ◽  
Variable Quantity ◽  
Cell Pellet ◽  
Fat Fraction ◽  
Dna Profiles ◽  
Future Work

AbstractAnalysis of the human milk microbiome is complicated by the presence of a variable quantity of fat. The fat fraction of human milk is typically discarded prior to analysis. It is assumed that all cells are pelleted out of human milk by high speed centrifugation; however, studies of bovine milk have reported that bacteria may remain trapped within the fat fraction. Here, the bacterial DNA profiles of the fat fraction and cell pellet of human milk (n = 10) were analysed. Human and bacterial DNA was consistently recovered from the fat fraction of human milk (average of 12.4% and 32.7%, respectively). Staphylococcus epidermidis was significantly more abundant in the cell pellet compared to the fat fraction (P = 0.038), and three low-abundance species (< 5% relative abundance) were recovered from one fraction only. However, inclusion of fat reduced the efficiency of DNA extraction by 39%. Culture-based methods were used to quantify the distribution of an exogenously added strain of Staphylococcus aureus in human milk fractions. S. aureus was consistently recovered from the fat fraction (average 28.9%). Bacterial DNA profiles generated from skim milk or cell pellets are not representative of the entire human milk microbiome. These data have critical implications for the design of future work in this field.

Distribution of plasminogen activator in different fractions of bovine milk

1995 ◽  
Vol 62 (1) ◽  
pp. 115-122 ◽  
Author(s):  
Jeffrey H. White ◽  
Boris Zavizion ◽  
Kristen O'Hare ◽  
James Gilmore ◽  
Ming R. Guo ◽  
...  
Keyword(s):  
Plasminogen Activator ◽  
Somatic Cells ◽  
Bovine Milk ◽  
Skim Milk ◽  
Raw Milk ◽  
Sds Page ◽  
Predominant Form ◽  
Cell Pellet ◽  
Molecular Masses ◽  
Milk Casein

SUMMARYThe type and relative amounts of plasminogen activator (PA) in different fractions of bovine milk obtained from 15 Holstein cows were examined. Raw milk was centrifuged to separate skim milk and a somatic cell pellet. PA was mainly localized within the casein fraction, being 42 times that in the serum, and in association with somatic cells. The predominant form of PA in milk casein was isolated from SDS-PAGE gel extracts and had a molecular mass of ∽75 kDa. Its activity was increased 41-fold (P < 0·01) in the presence of fibrin but was unaffected by the presence of amiloride, indicating that it was due to tissue-PA. The predominant forms of PA associated with milk somatic cells were isolated from SDS-PAGE gel extracts and had molecular masses of ∽ 30 and ∽ 50 kDa. The activity of both proteins was unaffected by the presence of fibrin but was dramatically reduced by the presence of amiloride, indicating that they represented urokinase-PA.

Proteins of human milk. I. Identification of major components.

1982 ◽  
Vol 28 (4) ◽  
pp. 1045-1055 ◽  
Author(s):  
N G Anderson ◽  
M T Powers ◽  
S L Tollaksen
Keyword(s):  
Human Milk ◽  
Whey Proteins ◽  
Bovine Milk ◽  
Skim Milk ◽  
Milk Proteins ◽  
Relative Molecular Mass ◽  
Isoelectric Points ◽  
Beta Casein ◽  
Dimensional Electrophoresis ◽  
New Protein

Abstract Traditionally, human milk proteins are identified largely by reference to bovine milk. Hence, to identify the major proteins in human milk, we subjected human and bovine milk, in parallel, to high-resolution two-dimensional electrophoresis. Isoelectric precipitation at pH 4.6 was our criterion for distinguishing whey proteins from those of the casein complex. The alpha- and beta-caseins were identified on the basis of relative abundance, relative molecular mass, and relative isoelectric points. Kappa casein was identified as a series of four spots, which disappear from bovine skim milk treated with rennin (chymosin; EC 3.4.23.4) during the clotting process. Para kappa-casein does not appear on the standard ISO-DALT pattern after treatment of bovine milk with rennin, but does appear in BASO-DALT pattern, indicating its high isoelectric point. No protein disappeared from ISO-DALT patterns of human milk after rennin treatment, and no new protein comparable to bovine para kappa-casein appeared in the BASO-DALT patterns; this suggests that kappa-casein is absent from human milk. The proteins identified in human milk patterns include the alpha and beta casein families, lactalbumin, albumin, transferrin, IgA, and lactoferrin. Numerous additional proteins seen in patterns for human milk remain to be identified.

Zinc binding in bovine milk

1989 ◽  
Vol 56 (2) ◽  
pp. 249-263 ◽  
Author(s):  
Harjinder Singh ◽  
Albert Flynn ◽  
Patrick F. Fox
Keyword(s):  
Calcium Phosphate ◽  
Human Milk ◽  
Equilibrium Dialysis ◽  
Bovine Milk ◽  
Skim Milk ◽  
Zinc Binding ◽  
Casein Micelles ◽  
Infant Formulae ◽  
Colloidal Calcium Phosphate ◽  
Acid Whey

SummaryAbout 90% of the Zn in bovine skim milk was sedimented by ultracentrifugation at 100000 g for 1 h. About half of the non-sedimentable Zn was non-dialysable, indicating that it was associated with protein, probably non-sedimented casein micelles. Casein micelles incorporated considerable amounts of Zn added to skim milk as ZnCl2, and at Zn concentrations ≥ 16 mM coagulation of casein micelles occurred. Ca was displaced from casein micelles by increasing ZnCl2 concentration and ˜ 40% of micellar Ca was displaced by 16 mM-ZnCl2. Micellar Zn, Ca and P1 were gradually rendered soluble as the pH of milk was lowered and at pH 4·6 > 95% of the Zn, Ca and P1 were non-sedimentable. These changes were largely reversible by readjustment of the pH to 6·7. About 40% of the total Zn in skim milk was non-sedimentable at 0·2 mM-EDTA and most of the remainder was gradually rendered soluble by EDTA over the concentration range 1–50 mM. This indicates that there are two distinct micellar Zn fractions. No micellar Ca or P1 was solubilized at EDTA concentrations up to 1·0 mM, indicating that both colloidal calcium phosphate (CCP) and casein micelles remained intact under conditions where the more loosely bound micellar Zn fraction dissolved. Depletion of casein micelles of colloidal Ca and P1 by acidification and equilibrium dialysis resulted in removal of Zn, and in colloidal Pi-free milk non-dialysable Zn was reduced to ·-2 mg/1 (˜ 32% of the original Zn). Thus, ˜ 32% of the Zn in skim milk is directly bound to caseins, while ˜ 63% is associated with CCP. Over 80% of the Zn in colloidal Pi-free milk was rendered soluble by 0·2 mM-EDTA, indicating that the casein-bound Zn is the loosely bound Zn fraction in casein micelles. A considerable fraction of the Zn in acid whey (pH 4·6) co-precipitated with Ca and Pi on raising the pH to 6·7 and heating for 2 h at 40 °C, indicating that insoluble Zn phosphate complexes form readily under these conditions. Studies on dialysis of milk against water, or dilution of milk or casein micelles with water, showed that CCP and its associated Zn is very stable and dissolves only very slowly at pH 6·6. The nature of Zn binding in casein micelles may help to explain the lower nutritional bioavailability of Zn in bovine milk and infant formulae compared with human milk.

Milk enzymes—their distribution and activity

1970 ◽  
Vol 37 (2) ◽  
pp. 279-288 ◽  
Author(s):  
B. J. Kitchen ◽  
G. C. Taylor ◽  
I. C. White
Keyword(s):  
Carbonic Anhydrase ◽  
Specific Activity ◽  
Bovine Milk ◽  
Skim Milk ◽  
Total Activity ◽  
Carbonic Anhydrase Activity ◽  
Ammonium Sulphate Precipitation ◽  
Milk Serum ◽  
Fat Fraction ◽  
Mastitic Milk

SummaryThe distribution and activity of alkaline phosphatase (E.C. 3.1.3.1), acid phosphatase (E.C. 3.1.3.2), catalase (E.C. 1.11.1.6), xanthine oxidase (E.C. 1.2.3.2), aldolase (E.C. 4.1.2.7 and 4.1.2.13), ribonuclease (E.C. 2.7.7.16) and carbonic anhydrase (E.C. 4.2.1.1) were studied in the major components of bovine milk. Fractionation was accomplished by centrifugation of milk, skim-milk and buttermilk, and ammonium sulphate precipitation of skim-milk serum. The range of activities found for the enzymes studied are tabulated together with the activities of some of the enzymes in mastitic milk, and the significance of the results obtained is discussed. No carbonic anhydrase activity was detected in any of the samples tested. The other enzymes studied were found to have a greater proportion of their total activity located in the skim-milk fraction. However, all of these enzymes except ribonuclease had a higher specific activity in the fat fraction.

A Retrospective Analysis of the Effects of an Exclusively Human Milk Protein Diet on Neonatal Feeding Tolerance

2020 ◽  
Author(s):  
Jessica Wickland ◽  
Christine Wade ◽  
Becky Micetic ◽  
Keith Meredith ◽  
Gregory Martin
Keyword(s):  
Birth Weight ◽  
Human Milk ◽  
Milk Protein ◽  
Very Low Birth Weight ◽  
Bovine Milk ◽  
Milk Diet ◽  
Vlbw Infants ◽  
Key Points ◽  
Human Milk Protein ◽  
Feeding Tolerance

Objective This study was aimed to evaluate the effect of human milk protein fortifier (HMPF) versus bovine milk protein fortifier (BMPF) on feeding tolerance defined as the time to reach full feeds and necrotizing enterocolitis (NEC) in premature very low birth weight (VLBW) infants. Study Design A retrospective review using the BabySteps Database included 493 infants born ≤33 weeks of gestational age and ≤1,250 g (g) birth weight. A total of 218 infants fed a human milk diet (HMD) with BMPF were compared with 275 infants fed an HMD with HMPF. Results Full feeds were reached significantly sooner in the HMPF group (median: 14 vs. 16 days, p = 0.04). Weight at full feeds was significantly lower in the HMPF group (1,060 vs. 1110 g, p = 0.03). Conclusion Using HMPF to provide an exclusively HMD allowed VLBW infants to achieve full feeds sooner, but did not affect rate of NEC compared with using a BMPF with an HMD. Key Points

Characteristic properties of AlTiN and TiN coated HSS materials

2015 ◽  
Vol 67 (2) ◽  
pp. 172-180 ◽  
Author(s):  
Mumin Sahin ◽  
Cenk Misirli ◽  
Dervis Özkan
Keyword(s):  
Surface Roughness ◽  
Tensile Strength ◽  
High Speed ◽  
Cutting Tools ◽  
High Speed Steel ◽  
Wear Properties ◽  
Content Type ◽  
X Ray ◽  
Number Of Cycles ◽  
Future Work

Purpose – The purpose of this paper is to examine mechanical and metallurgical properties of AlTiN- and TiN-coates high-speed steel (HSS) materials in detail. Design/methodology/approach – In this study, HSS steel parts have been processed through machining and have been coated with AlTiN and TiN on physical vapour deposition workbench at approximately 6,500°C for 4 hours. Tensile strength, fatigue strength, hardness tests for AlTiN- and TiN-coated HSS samples have been performed; moreover, energy dispersive X-ray spectroscopy and X-ray diffraction analysis and microstructure analysis have been made by scanning electron microscopy. The obtained results have been compared with uncoated HSS components. Findings – It was found that tensile strength of TiAlN- and TiN-coated HSS parts is higher than that of uncoated HSS parts. Highest tensile strength has been obtained from TiN-coated HSS parts. Number of cycles for failure of TiAlN- and TiN-coated HSS parts is higher than that for HSS parts. Particularly TiN-coated HSS parts have the most valuable fatigue results. However, surface roughness of fatigue samples may cause notch effect. For this reason, surface roughness of coated HSS parts is compared with that of uncoated ones. While the average surface roughness (Ra) of the uncoated samples was in the range of 0.40 μm, that of the AlTiN- and TiN-coated samples was in the range of 0.60 and 0.80 μm, respectively. Research limitations/implications – It would be interesting to search different coatings for cutting tools. It could be the good idea for future work to concentrate on wear properties of tool materials. Practical implications – The detailed mechanical and metallurgical results can be used to assess the AlTiN and TiN coating applications in HSS materials. Originality/value – This paper provides information on mechanical and metallurgical behaviour of AlTiN- and TiN-coated HSS materials and offers practical help for researchers and scientists working in the coating area.

Bovine milk esterases

1971 ◽  
Vol 38 (2) ◽  
pp. 171-177 ◽  
Author(s):  
B. J. Kitchen
Keyword(s):  
Ammonium Sulphate ◽  
Bovine Milk ◽  
Skim Milk ◽  
Histochemical Staining ◽  
Major Type ◽  
Polyacrylamide Gels ◽  
Selective Inhibitors ◽  
Choline Ester ◽  
Ultra Filtration ◽  
Ammonium Sulphate Fractionation

SummaryThe type and distribution of esterases in milk has been investigated using selective inhibitors during normal assay procedures and during histochemical staining of polyacrylamide gels. Enzyme solutions were obtained from skim-milk by acid and alkali precipitation, followed by ammonium sulphate fractionation, ultra-filtration and Sephadex G-100 chromatography. The major type of esterase present was an aryl-esterase (E.C. 5.1.1.2) while a smaller amount of a choline-ester hydrolase (E.C. 3.1.1.7; 3.1.1.8) was detected. The significance of these findings is discussed.

scholarly journals Comparison of methods for milk pre-processing, exosome isolation, and RNA extraction in bovine and human milk

2020 ◽  
Author(s):  
Sanoji Wijenayake ◽  
Shafinaz Eisha ◽  
Zoya Tawhidi ◽  
Michael A. Pitino ◽  
Michael A. Steele ◽  
...  
Keyword(s):  
Human Milk ◽  
Biological Fluid ◽  
Rna Extraction ◽  
Bovine Milk ◽  
Total Soluble Protein ◽  
Long Term Storage ◽  
Transmission Electron ◽  
Whole Milk ◽  
Membrane Bound

AbstractMilk is a highly complex, heterogeneous biological fluid that contains bioactive, membrane-bound extracellular vesicles called exosomes. Characterization of milk-derived exosomes (MDEs) is challenging due to the lack of standardized methods that are currently being used for milk pre-processing, exosome isolation, and RNA extraction. In this study, we tested: 1) three pre-processing methods to remove cream, fat, and casein proteins from bovine milk to determine whether pre-processing of whole milk, prior to long-term storage, improves MDE isolations, 2) two commonly-used exosome isolation methods, and 3) four extraction protocols for obtaining high quality MDE RNA from bovine and human milk. MDEs were characterized via Transmission Electron Microscopy (TEM) and Nanoparticle Tracking Analysis (NTA). We also present an optimized method of TEM sample preparation and isolation of total soluble protein from MDEs. Our results indicated that: 1) pre-processing of bovine milk prior to storage does not affect the final exosome yield or the purity, 2) ExoQuick precipitation is better suited for MDE isolation than ultracentrifugation for bovine and human milk, and 3) TRIzol LS produced the highest RNA yield in bovine milk, whereas TRIzol LS, TRIzol+RNA Clean and Concentrator, and TRIzol LS+RNA Clean and Concentrator methods can be used for human milk.

Summary-The Early Feeds: Human Milk Versus Formula and Bovine Milk

PEDIATRICS ◽  
1985 ◽  
Vol 75 (1) ◽  
pp. 157-159
Keyword(s):  
Breast Milk ◽  
Human Milk ◽  
Whey Proteins ◽  
Bovine Milk ◽  
Milk Proteins ◽  
Human Infant ◽  
Postnatal Life ◽  
Human Breast Milk ◽  
Nonprotein Nitrogen ◽  
Casein Protein

Adaptations of the gastrointestinal tract and the immune system that take place during the first year of postnatal life are of great importance, initially facilitating the transition between gestation and lactation, ultimately supporting independent postnatal life. When considering feeding options during the early periods, the roles of human milk, commercially prepared formula, and bovine milk must be evaluated in light of recent knowledge of these adaptations. Since infant feeding practices and the biologic capabilities of infants themselves vary significantly, the question arises as to what is "acceptable" v what is "optimal." NUTRITIONAL PROTEINS At present, evaluations of the amount of protein required for infant growth are based on clinical studies of largē populations and include a "margin of safety" to meet the needs of the individual infant. Based on the assumption that the milk of a given species is best adapted to the nutrient requirements of the young of that species, human infant protein requirements are determined by the protein contribution of human breast milk. Breast-milk proteins are defined broadly as either whey or casein protein with an approximate ratio of 70:30, respectively. The casein portion is divided into three subgroups: α,β and κ casein. Whey proteins are divided into six major subgroups: α-lactalbumin, β-lactoglobulin; lactoferrin; serum-albumin; lysozyme, and immunoglobulins A, G, and M. Numerous nonprotein nitrogen substances including taurine exist as well. Protein Availability Protein concentration of breast milk is approximately 1.2 g/dL when measured as total nitrogen. Nearly 25% of this is nonprotein nitrogen, much of which may not be used for nutritional purposes.

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