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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 stallion SP proteins and interaction between stallion BSP proteins and milk proteins. a Gel filtration chromatogram of 1.75 mg of stallion SP proteins alone (open circles) or after incubation with skimmed milk (solid circles). b Immunoblot analysis of fractions from the elution of stallion SP proteins alone. Following the elution, aliquots equivalent to 6 % of tubes from five fractions (1, tubes 43–51; 2, tubes 52–74; 3, tubes 75–100; 4, tubes 101–126 and 5, tubes 127–141). c Immunoblot analysis of pooled fractions from the elution of stallion SP proteins incubated with skimmed milk. SP, stallion seminal plasma proteins (300 ng). Following elution, fractions were pooled in seven fractions (I, tubes 43–51; II, tubes 52–70; III, tubes 71–90; IV, tubes 91–100; V, tubes 101–110; VI, tubes 111–120 and VII, tubes 121–148). Aliquots equivalent to 0.3 % of each fraction were precipitated. The experiments were carried out in triplicates and the results of one typical experiment are shown
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Fig5: Gel filtration analysis of stallion SP proteins and interaction between stallion BSP proteins and milk proteins. a Gel filtration chromatogram of 1.75 mg of stallion SP proteins alone (open circles) or after incubation with skimmed milk (solid circles). b Immunoblot analysis of fractions from the elution of stallion SP proteins alone. Following the elution, aliquots equivalent to 6 % of tubes from five fractions (1, tubes 43–51; 2, tubes 52–74; 3, tubes 75–100; 4, tubes 101–126 and 5, tubes 127–141). c Immunoblot analysis of pooled fractions from the elution of stallion SP proteins incubated with skimmed milk. SP, stallion seminal plasma proteins (300 ng). Following elution, fractions were pooled in seven fractions (I, tubes 43–51; II, tubes 52–70; III, tubes 71–90; IV, tubes 91–100; V, tubes 101–110; VI, tubes 111–120 and VII, tubes 121–148). Aliquots equivalent to 0.3 % of each fraction were precipitated. The experiments were carried out in triplicates and the results of one typical experiment are shown

Mentions: Similar experiments were conducted using Stallion SP. Seminal plasma alone eluted from the Sepharose CL-4B column as a small peak at the end of the elution pattern (Fig. 5a; open circles). Equivalent proportions of pooled fractions (1–5) were analyzed by immunoblot using polyclonal antibodies directed against stallion BSP proteins (Fig. 5b). Stallion BSP1 (22 kDa and 17 kDa) and BSP2 (16 kDa) were detected mainly in fractions 4 and 5. A faint amount of proteins was also detected in fraction 3.Fig. 5


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 stallion SP proteins and interaction between stallion BSP proteins and milk proteins. a Gel filtration chromatogram of 1.75 mg of stallion SP proteins alone (open circles) or after incubation with skimmed milk (solid circles). b Immunoblot analysis of fractions from the elution of stallion SP proteins alone. Following the elution, aliquots equivalent to 6 % of tubes from five fractions (1, tubes 43–51; 2, tubes 52–74; 3, tubes 75–100; 4, tubes 101–126 and 5, tubes 127–141). c Immunoblot analysis of pooled fractions from the elution of stallion SP proteins incubated with skimmed milk. SP, stallion seminal plasma proteins (300 ng). Following elution, fractions were pooled in seven fractions (I, tubes 43–51; II, tubes 52–70; III, tubes 71–90; IV, tubes 91–100; V, tubes 101–110; VI, tubes 111–120 and VII, tubes 121–148). Aliquots equivalent to 0.3 % of each fraction were precipitated. The experiments were carried out in triplicates 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

Fig5: Gel filtration analysis of stallion SP proteins and interaction between stallion BSP proteins and milk proteins. a Gel filtration chromatogram of 1.75 mg of stallion SP proteins alone (open circles) or after incubation with skimmed milk (solid circles). b Immunoblot analysis of fractions from the elution of stallion SP proteins alone. Following the elution, aliquots equivalent to 6 % of tubes from five fractions (1, tubes 43–51; 2, tubes 52–74; 3, tubes 75–100; 4, tubes 101–126 and 5, tubes 127–141). c Immunoblot analysis of pooled fractions from the elution of stallion SP proteins incubated with skimmed milk. SP, stallion seminal plasma proteins (300 ng). Following elution, fractions were pooled in seven fractions (I, tubes 43–51; II, tubes 52–70; III, tubes 71–90; IV, tubes 91–100; V, tubes 101–110; VI, tubes 111–120 and VII, tubes 121–148). Aliquots equivalent to 0.3 % of each fraction were precipitated. The experiments were carried out in triplicates and the results of one typical experiment are shown
Mentions: Similar experiments were conducted using Stallion SP. Seminal plasma alone eluted from the Sepharose CL-4B column as a small peak at the end of the elution pattern (Fig. 5a; open circles). Equivalent proportions of pooled fractions (1–5) were analyzed by immunoblot using polyclonal antibodies directed against stallion BSP proteins (Fig. 5b). Stallion BSP1 (22 kDa and 17 kDa) and BSP2 (16 kDa) were detected mainly in fractions 4 and 5. A faint amount of proteins was also detected in fraction 3.Fig. 5

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