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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 gelatin-adsorbed ram BSP proteins and milk fraction F1. a Chromatogram of gelatin-adsorbed ram BSP proteins (500 μg) incubated with milk fraction F1 (4.8 mg). Tubes were pooled to provide seven fractions (I, tubes 42–52; II, tubes 53–70; III, tubes 71–90; IV, tubes 91–100; V, tubes 101–110; VI, tubes 111–120 and VII, tubes 121–150). b Immunoblot analysis of chromatographic fractions. SP: ram SP proteins (300 ng). Aliquots equivalent to 5 % of the fractions were precipitated. Duplicates were carried out and the results of one typical experiment are shown
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Fig7: Gel filtration analysis of the interaction between gelatin-adsorbed ram BSP proteins and milk fraction F1. a Chromatogram of gelatin-adsorbed ram BSP proteins (500 μg) incubated with milk fraction F1 (4.8 mg). Tubes were pooled to provide seven fractions (I, tubes 42–52; II, tubes 53–70; III, tubes 71–90; IV, tubes 91–100; V, tubes 101–110; VI, tubes 111–120 and VII, tubes 121–150). b Immunoblot analysis of chromatographic fractions. SP: ram SP proteins (300 ng). Aliquots equivalent to 5 % of the fractions were precipitated. Duplicates were carried out and the results of one typical experiment are shown

Mentions: No clear indication of the binding of ram BSP proteins with milk F1 was observed. To investigate it ram gelatin-bound SP proteins (containing BSP proteins only) were incubated with milk F1 alone and chromatographed. Elution pattern showed only one large peak corresponding to milk F1 (Fig. 7a). The analysis of proteins demonstrated that BSP of 15–16 kDa were present in fraction I, whereas BSP 22–24 kDa were only found in fractions VI-VII (Fig. 7b).Fig. 7


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 gelatin-adsorbed ram BSP proteins and milk fraction F1. a Chromatogram of gelatin-adsorbed ram BSP proteins (500 μg) incubated with milk fraction F1 (4.8 mg). Tubes were pooled to provide seven fractions (I, tubes 42–52; II, tubes 53–70; III, tubes 71–90; IV, tubes 91–100; V, tubes 101–110; VI, tubes 111–120 and VII, tubes 121–150). b Immunoblot analysis of chromatographic fractions. SP: ram SP proteins (300 ng). Aliquots equivalent to 5 % of the fractions were precipitated. Duplicates were carried out and the results of one typical experiment are shown
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4536704&req=5

Fig7: Gel filtration analysis of the interaction between gelatin-adsorbed ram BSP proteins and milk fraction F1. a Chromatogram of gelatin-adsorbed ram BSP proteins (500 μg) incubated with milk fraction F1 (4.8 mg). Tubes were pooled to provide seven fractions (I, tubes 42–52; II, tubes 53–70; III, tubes 71–90; IV, tubes 91–100; V, tubes 101–110; VI, tubes 111–120 and VII, tubes 121–150). b Immunoblot analysis of chromatographic fractions. SP: ram SP proteins (300 ng). Aliquots equivalent to 5 % of the fractions were precipitated. Duplicates were carried out and the results of one typical experiment are shown
Mentions: No clear indication of the binding of ram BSP proteins with milk F1 was observed. To investigate it ram gelatin-bound SP proteins (containing BSP proteins only) were incubated with milk F1 alone and chromatographed. Elution pattern showed only one large peak corresponding to milk F1 (Fig. 7a). The analysis of proteins demonstrated that BSP of 15–16 kDa were present in fraction I, whereas BSP 22–24 kDa were only found in fractions VI-VII (Fig. 7b).Fig. 7

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