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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 ram SP proteins and interaction between ram BSP proteins and milk proteins. a Gel filtration chromatogram of 1.75 mg of ram SP proteins alone (open circles) or after incubation with skimmed milk (solid circles). Following the elution, tubes were pooled to provide five fractions for ram SP proteins alone (1, tubes 40–50; 2, tubes 51–80; 3, tubes 81–100; 4, tubes 101–130 and 5, tubes 131–141) or seven fractions for SP incubated with milk (I, tubes 40–50; II, tubes 51–70; III, tubes 71–90; IV, tubes 91–100; V, tubes 101–110; VI, tubes 110–120 and VII, tubes 121–142). Aliquots equivalent to 3 % of each fraction were precipitated and used for immunoblots. b Immunoblot analysis of pooled fractions from the elution of ram SP proteins alone. SP, ram seminal plasma proteins (300 ng). c Immunoblot analysis of pooled fractions from the elution of ram SP proteins incubated with skimmed milk. The experiments were carried out in triplicates and the results of one typical experiment are shown
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Fig6: Gel filtration analysis of ram SP proteins and interaction between ram BSP proteins and milk proteins. a Gel filtration chromatogram of 1.75 mg of ram SP proteins alone (open circles) or after incubation with skimmed milk (solid circles). Following the elution, tubes were pooled to provide five fractions for ram SP proteins alone (1, tubes 40–50; 2, tubes 51–80; 3, tubes 81–100; 4, tubes 101–130 and 5, tubes 131–141) or seven fractions for SP incubated with milk (I, tubes 40–50; II, tubes 51–70; III, tubes 71–90; IV, tubes 91–100; V, tubes 101–110; VI, tubes 110–120 and VII, tubes 121–142). Aliquots equivalent to 3 % of each fraction were precipitated and used for immunoblots. b Immunoblot analysis of pooled fractions from the elution of ram SP proteins alone. SP, ram seminal plasma proteins (300 ng). c Immunoblot analysis of pooled fractions from the elution of ram SP proteins incubated with skimmed milk. The experiments were carried out in triplicates and the results of one typical experiment are shown

Mentions: When ram SP proteins were loaded into the Sepharose CL-4B column, a small protein peak was observed (Fig. 6a, open circles). Immunoblot of equivalent proportions of the pooled fractions was performed using polyclonal antibodies directed against ram BSP proteins. The polyclonal antibodies recognized mainly the 22–24 kDa ram BSP proteins, which were detected strongly in fraction 4 and weakly in fraction 5 (Fig. 6b). A very faint band corresponding to the 15–16 kDa ram BSP proteins was detected in fraction 4, possibly because of their very low concentration in ram SP and of the dilution factor associated with gel filtration.Fig. 6


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 ram SP proteins and interaction between ram BSP proteins and milk proteins. a Gel filtration chromatogram of 1.75 mg of ram SP proteins alone (open circles) or after incubation with skimmed milk (solid circles). Following the elution, tubes were pooled to provide five fractions for ram SP proteins alone (1, tubes 40–50; 2, tubes 51–80; 3, tubes 81–100; 4, tubes 101–130 and 5, tubes 131–141) or seven fractions for SP incubated with milk (I, tubes 40–50; II, tubes 51–70; III, tubes 71–90; IV, tubes 91–100; V, tubes 101–110; VI, tubes 110–120 and VII, tubes 121–142). Aliquots equivalent to 3 % of each fraction were precipitated and used for immunoblots. b Immunoblot analysis of pooled fractions from the elution of ram SP proteins alone. SP, ram seminal plasma proteins (300 ng). c Immunoblot analysis of pooled fractions from the elution of ram SP proteins incubated with skimmed milk. The experiments were carried out in triplicates and the results of one typical experiment are shown
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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Fig6: Gel filtration analysis of ram SP proteins and interaction between ram BSP proteins and milk proteins. a Gel filtration chromatogram of 1.75 mg of ram SP proteins alone (open circles) or after incubation with skimmed milk (solid circles). Following the elution, tubes were pooled to provide five fractions for ram SP proteins alone (1, tubes 40–50; 2, tubes 51–80; 3, tubes 81–100; 4, tubes 101–130 and 5, tubes 131–141) or seven fractions for SP incubated with milk (I, tubes 40–50; II, tubes 51–70; III, tubes 71–90; IV, tubes 91–100; V, tubes 101–110; VI, tubes 110–120 and VII, tubes 121–142). Aliquots equivalent to 3 % of each fraction were precipitated and used for immunoblots. b Immunoblot analysis of pooled fractions from the elution of ram SP proteins alone. SP, ram seminal plasma proteins (300 ng). c Immunoblot analysis of pooled fractions from the elution of ram SP proteins incubated with skimmed milk. The experiments were carried out in triplicates and the results of one typical experiment are shown
Mentions: When ram SP proteins were loaded into the Sepharose CL-4B column, a small protein peak was observed (Fig. 6a, open circles). Immunoblot of equivalent proportions of the pooled fractions was performed using polyclonal antibodies directed against ram BSP proteins. The polyclonal antibodies recognized mainly the 22–24 kDa ram BSP proteins, which were detected strongly in fraction 4 and weakly in fraction 5 (Fig. 6b). A very faint band corresponding to the 15–16 kDa ram BSP proteins was detected in fraction 4, possibly because of their very low concentration in ram SP and of the dilution factor associated with gel filtration.Fig. 6

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