Concentrations and Anti-Haemophilus influenzae Activities of β-Casein Phosphoforms in Human Milk
| Autor: | Steven A. Anderson, Pradip Mukerji, Robert George Hards, Linda Ann Harvey, Jeffrey H. Baxter, Terry A. Kroening |
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| Rok vydání: | 1999 |
| Předmět: |
Gel electrophoresis
Milk Human biology Pasteurellaceae Gastroenterology Caseins Fractionation Phosphoproteins biology.organism_classification medicine.disease_cause Antiviral Agents Haemophilus influenzae In vitro Microbiology Casein Pediatrics Perinatology and Child Health medicine Humans Urea Electrophoresis Polyacrylamide Gel Female Polyacrylamide gel electrophoresis Bacteria |
| Zdroj: | Journal of Pediatric Gastroenterology & Nutrition. 28:486-491 |
| ISSN: | 0277-2116 |
| DOI: | 10.1097/00005176-199905000-00008 |
| Popis: | Background: The distribution and concentrations of six phosphorylated forms of human β-casein, a major source of nutrition among breast-fed infants, have not been examined in milk samples without prior fractionation. In this study, the levels of β-casein phosphoforms in untreated human milk samples were analyzed and their antiadhesion activities determined against Haemophilus influenzae, a pathogen implicated in middle ear infection in infants. Methods: Human milk samples were analyzed using urea-polyacrylamide gel electrophoresis of whole-milk samples and scanning densitometry to determine the concentrations of @-casein and its phosphoforms. A nontypable H. influenzae strain was radiolabeled to monitor its attachment to human pharyngeal cells in microtiter plates. Purified phosphoforms of @-casein were preincubated for 15 minutes with radiolabeled bacteria to determine their antiadhesion activities. Results: The average β-casein concentration in 151 human milk samples was 5.37 ± 2.26 mg/ml. On average, the phosphoforms in untreated milk are present in the following order ranked by concentration: tetra- > di- > non- > mono- > tri- > pentaphosphorylated β-casein. The tri-, tetra-, and pentaphosphorylated forms of human β-casein exhibited more than 60% inhibition of H. influenzae in the antiadhesion assay when used at a concentration of 0.6 to 0.9 mg/ml. Conclusion: The β-casein level in untreated human milk is significantly higher than previously reported. The phosphoform distribution of β-casein in individual donors varies widely. Anti-H. influenzae activity was detected in vitro among human β-casein molecules with three or more phosphate groups. |
| Databáze: | OpenAIRE |
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