Ribonucleic acid synthesis continues at a low rate within 1 h of germinal vesicle breakdown. To determine if this newly synthesized mRNA is required for the resumption of meiosis in cattle oocytes, cumulus-enclosed oocytes were removed from 2 to 4-mm antral follicles directly into Dulbecco's medium with or without the RNA inhibitor, alpha-amanitin, or the protein synthesis inhibitor, cycloheximide (10 micrograms/ml). They were washed twice and matured for 28 or 48 h in medium 199, with Earle's salts, 2.2 g/L NaHCO3 and L-glutamine supplemented with 20% heated fetal calf serum to which were added gonadotropins (10 micrograms/ml NIH-LH-S18; 10 micrograms/ml NIH-FSH-S8; 20 ng/ml NIH-P-S9), estradiol-17 beta (1.5 micrograms/ml), solcoseryl (30 microliter/ml), and Dibekacin sulfate (100 micrograms/ml) with or without the inhibitors. After 28 h of maturation, 95.8% of control oocytes had undergone germinal vesicle breakdown and formation of a metaphase plate compared with only 1.3% of those continuously exposed to cycloheximide and 38% of those continuously exposed to amanitin. Exposure to cycloheximide or amanitin for only the first 16 h of culture followed by 12 h of inhibitor free culture resulted in 96.6% germinal vesicle breakdown with cycloheximide but only 56.5% germinal vesicle breakdown with amanatin. We conclude newly synthesized mRNA and protein synthesis is required for both full cumulus cell expansion and germinal vesicle breakdown.
Colostral changes in immunoglobulin (IgG), dry matter, ash, total protein, and whey protein were studied over the first three milkings postpartum. Immunoglobulin IgG concentration in colostrum from Holstein cows beginning their first, second, or third lactation was similar. However, older animals had more IgG in colostrum. Its rate of disappearance from colostrum was greater in younger animals. Dry matter, ash, total protein, and whey protein concentrations decreased from the first to the third milking (24 h) postpartum. Protein was the most variable constituent between cows at the same postpartum time.
Summary. The relationship between the sperm-coating antigens of rabbit seminal plasma and the phenomenon of decapacitation was studied using agar-gel diffusion, immuno-electrophoresis, chromatography on Sephadex G-200, and polyacrylamide vertical gel electrophoresis.Interpretation of data obtained with these techniques led to the conclusion that a sperm-coating antigen of seminal plasma origin possessed biological activity for blocking fertilization. The sperm-coating antigen was a glycoprotein of approximately 170,000 molecular weight, migrated in an electric field similar to a serum slow \g=b\-globulin and was still present in the seminal fluid of vasectomized males. This sperm\x=req-\ coating antigen was absent from the inactive upper supernatant fluid fraction of seminal plasma after 4 hr of ultracentrifugation at 105,000 g and was present in the active ultracentrifugal pellet.
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