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Interaction of milk proteins and Binder of Sperm (BSP) proteins from boar, stallion and ram semen.

Plante G, Lusignan MF, Lafleur M, Manjunath P - Reprod. Biol. Endocrinol. (2015)

Bottom Line: These changes can ultimately be detrimental to sperm storage.They also had affinity for another milk protein fraction (F2) composed mostly of casein micelles.However, stallion BSP showed higher affinity for the fraction (F1).

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Université de Montréal, C.P. 6128, Succ. Centre Ville, Montréal, Québec, Canada, H3C 3J7. genevieve.plante@umontreal.ca.

ABSTRACT

Background: Mammalian semen contains a family of closely related proteins known as Binder of SPerm (BSP proteins) that are added to sperm at ejaculation. BSP proteins extract lipids from the sperm membrane thereby extensively modifying its composition. These changes can ultimately be detrimental to sperm storage. We have demonstrated that bovine BSP proteins interact with major milk proteins and proposed that this interaction could be the basis of sperm protection by milk extenders. In the present study, we investigated if homologous BSP proteins present in boar, stallion and ram seminal plasma display a similar affinity for the milk proteins in order to assess whether the mechanism of sperm protection by milk for these species could be general.

Methods: Skim milk was incubated with seminal plasma proteins (boar, stallion and ram), chromatographed on a Sepharose CL-4B column and protein fractions were analyzed by immunoblotting.

Results: Boar, stallion and ram BSP proteins displayed affinity for a milk protein fraction (F1) mainly composed of α-lactalbumin, β-lactoglobulin, and κ-casein. They also had affinity for another milk protein fraction (F2) composed mostly of casein micelles. However, stallion BSP showed higher affinity for the fraction (F1).

Conclusions: These results further extend our view that the association of BSP proteins with milk proteins could be a general feature of the mechanism of mammalian sperm protection by milk to prevent detrimental effect of prolonged exposure of sperm to seminal plasma.

No MeSH data available.


Related in: MedlinePlus

Gel filtration analysis of the interaction between pure boar BSP1 proteins and isolated milk fractions F1 and F2. a, b Chromatogram of purified boar BSP1 (100 μg) incubated with milk fraction F1 (2.9 mg) or milk fraction 2 (16.2 mg) respectively. Following the elution from both columns, tubes were pooled to provide seven fractions (I, tubes 41–47; II, tubes 48–67; III, tubes 68–87; IV, tubes 88–95; V, tubes 96–104; VI, tubes 105–113 and VII, tubes 114–146). c, d Immunoblot analysis of chromatographic fractions. Aliquots equivalent to 20 % of the pooled fractions were precipitated for the analysis. Duplicates were carried out and the results of one typical experiment are shown
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Fig4: Gel filtration analysis of the interaction between pure boar BSP1 proteins and isolated milk fractions F1 and F2. a, b Chromatogram of purified boar BSP1 (100 μg) incubated with milk fraction F1 (2.9 mg) or milk fraction 2 (16.2 mg) respectively. Following the elution from both columns, tubes were pooled to provide seven fractions (I, tubes 41–47; II, tubes 48–67; III, tubes 68–87; IV, tubes 88–95; V, tubes 96–104; VI, tubes 105–113 and VII, tubes 114–146). c, d Immunoblot analysis of chromatographic fractions. Aliquots equivalent to 20 % of the pooled fractions were precipitated for the analysis. Duplicates were carried out and the results of one typical experiment are shown

Mentions: To confirm this interaction, milk fractions F1 and F2 were separated, incubated individually with pure boar BSP1 and chromatographed on a Sepharose CL-4B column (Fig. 4a-b). When incubated with milk F1, BSP1 was found solely in fraction I, and when incubated with milk F2 alone, it was found only in fraction IV (Fig. 4c-d). This clearly demonstrates the interaction of boar BSP1 with both milk fractions.Fig. 4


Interaction of milk proteins and Binder of Sperm (BSP) proteins from boar, stallion and ram semen.

Plante G, Lusignan MF, Lafleur M, Manjunath P - Reprod. Biol. Endocrinol. (2015)

Gel filtration analysis of the interaction between pure boar BSP1 proteins and isolated milk fractions F1 and F2. a, b Chromatogram of purified boar BSP1 (100 μg) incubated with milk fraction F1 (2.9 mg) or milk fraction 2 (16.2 mg) respectively. Following the elution from both columns, tubes were pooled to provide seven fractions (I, tubes 41–47; II, tubes 48–67; III, tubes 68–87; IV, tubes 88–95; V, tubes 96–104; VI, tubes 105–113 and VII, tubes 114–146). c, d Immunoblot analysis of chromatographic fractions. Aliquots equivalent to 20 % of the pooled fractions were precipitated for the analysis. Duplicates were carried out and the results of one typical experiment are shown
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4536704&req=5

Fig4: Gel filtration analysis of the interaction between pure boar BSP1 proteins and isolated milk fractions F1 and F2. a, b Chromatogram of purified boar BSP1 (100 μg) incubated with milk fraction F1 (2.9 mg) or milk fraction 2 (16.2 mg) respectively. Following the elution from both columns, tubes were pooled to provide seven fractions (I, tubes 41–47; II, tubes 48–67; III, tubes 68–87; IV, tubes 88–95; V, tubes 96–104; VI, tubes 105–113 and VII, tubes 114–146). c, d Immunoblot analysis of chromatographic fractions. Aliquots equivalent to 20 % of the pooled fractions were precipitated for the analysis. Duplicates were carried out and the results of one typical experiment are shown
Mentions: To confirm this interaction, milk fractions F1 and F2 were separated, incubated individually with pure boar BSP1 and chromatographed on a Sepharose CL-4B column (Fig. 4a-b). When incubated with milk F1, BSP1 was found solely in fraction I, and when incubated with milk F2 alone, it was found only in fraction IV (Fig. 4c-d). This clearly demonstrates the interaction of boar BSP1 with both milk fractions.Fig. 4

Bottom Line: These changes can ultimately be detrimental to sperm storage.They also had affinity for another milk protein fraction (F2) composed mostly of casein micelles.However, stallion BSP showed higher affinity for the fraction (F1).

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Université de Montréal, C.P. 6128, Succ. Centre Ville, Montréal, Québec, Canada, H3C 3J7. genevieve.plante@umontreal.ca.

ABSTRACT

Background: Mammalian semen contains a family of closely related proteins known as Binder of SPerm (BSP proteins) that are added to sperm at ejaculation. BSP proteins extract lipids from the sperm membrane thereby extensively modifying its composition. These changes can ultimately be detrimental to sperm storage. We have demonstrated that bovine BSP proteins interact with major milk proteins and proposed that this interaction could be the basis of sperm protection by milk extenders. In the present study, we investigated if homologous BSP proteins present in boar, stallion and ram seminal plasma display a similar affinity for the milk proteins in order to assess whether the mechanism of sperm protection by milk for these species could be general.

Methods: Skim milk was incubated with seminal plasma proteins (boar, stallion and ram), chromatographed on a Sepharose CL-4B column and protein fractions were analyzed by immunoblotting.

Results: Boar, stallion and ram BSP proteins displayed affinity for a milk protein fraction (F1) mainly composed of α-lactalbumin, β-lactoglobulin, and κ-casein. They also had affinity for another milk protein fraction (F2) composed mostly of casein micelles. However, stallion BSP showed higher affinity for the fraction (F1).

Conclusions: These results further extend our view that the association of BSP proteins with milk proteins could be a general feature of the mechanism of mammalian sperm protection by milk to prevent detrimental effect of prolonged exposure of sperm to seminal plasma.

No MeSH data available.


Related in: MedlinePlus