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G D Ball

Publications and source records attributed to G D Ball.

30 records · Page 2Linked to original sources
PubMed1985

DNA, RNA, and protein synthesis by porcine oocyte-cumulus complexes during expansion.

The experiments described in this report were designed to determine three biosynthetic functions of oocyte-cumulus complexes during expansion. The events investigated were DNA, RNA, and protein synthesis during a 24-h in vitro culture; these were determined by 3H-thymidine, 3H-uridine, and 3H-leucine incorporation into oocyte-cumulus complexes, respectively. The quality of proteins produced was also determined by slab-gel electrophoresis. Results indicated that, during follicle-stimulating hormone-induced cumulus expansion, total DNA synthesis was significantly (P less than 0.05) reduced whereas RNA synthesis remained unchanged. Overall protein synthesis was markedly increased (P less than 0.05), with one major band (Mr = 22,000) and two minor bands (Mr = 19,500 and 78,000) being produced during expansion.

Animals↗
PubMed1985

Very large scale suspension cultures of mammalian cells.

Suspension cultures of mammalian cells can be used to produce virus vaccines, as a source of interferons, and as a host system for expressing inserted human genes. We will discuss the experience with this technology in our organisation over the past 18 years, during which we have progressively expanded our facilities for such work: we are now operating routinely with 8 000 litre fermenters. Information will be summarized in relation to the following topics: design of plant, medium and serum requirements, plant operation and product processing.

Cells, Cultured↗
PubMed1984

Maturation and fertilization of bovine oocytes in vitro.

This report is to review and summarize various aspects of maturation and fertilization of bovine oocytes. Reference also is made to other species where pertinent data for the bovine are unavailable. Finally, factors important to success of in vitro maturation and fertilization as well as applications of these procedures to the animal industry are addressed.

Animals↗
PubMed1983

Chondroitin sulfate facilitates an acrosome reaction in bovine spermatozoa as evidenced by light microscopy, electron microscopy and in vitro fertilization.

Bovine epididymal spermatozoa were incubated for 22 h in a modified Tyrode's medium. The percentages of sperm exhibiting an acrosome reaction were determined morphologically after fixing and staining specimens. The addition of chondroitin sulfate A (CS-A) significantly increased the incidence of acrosome reaction. When observed by electron microscopy, acrosome-reacted sperm had undergone vesiculation of the plasma and outer acrosomal membranes. Sperm incubated in the presence of CS-A demonstrated a significantly higher incidence of vesiculation when compared to the controls. Additionally, rates of in vitro fertilization of bovine oocytes were significantly elevated when sperm and ova were exposed to CS-A. These results suggest that glycosaminoglycans in the female reproductive tract may be responsible for some of the biochemical changes associated with fertilization, and a light microscope procedure can be used to assess occurrence of the acrosome reaction.

Acrosome↗
PubMed1983

Factors affecting successful in vitro fertilization of bovine follicular oocytes.

These experiments were designed to define and optimize the efficiency of a system whereby bovine oocytes could be fertilized in vitro. The frequency of ova penetrated and the stage of fertilization were the end points examined. All experiments utilized cumulus-oocyte complexes from 1- to 5-mm follicles which were matured in vitro prior to fertilization. The experiments were designed to examine the effects of the following factors on fertilization: 1) pretreatment of sperm with ionomycin (a Ca++ ionophore), 2) preincubation of sperm at a high concentration and the presence of hypotaurine and epinephrine during fertilization, 3) the use of either follicle-stimulating hormone (FSH) or cAMP for the induction of cumulus expansion prior to fertilization, and 4) the need for the presence of cumulus cells during fertilization. Sperm exposure to ionomycin or preincubation at high sperm concentrations was not necessary for fertilization. The presence of hypotaurine and epinephrine during fertilization improved (P less than 0.05) the quality of fertilization (i.e., higher frequencies of oocytes with both female and male pronuclei were observed). However, they did not increase the percentage of ova penetrated (P greater than 0.05). Fertilization frequencies were not different (P greater than 0.05) between oocytes with cumulus expansion induced by FSH or cAMP. However, the use of either treatment resulted in higher fertilization rates when compared to untreated controls (P less than 0.05). Finally, while the presence of cumulus cells was not necessary for penetration of ova, increased frequencies of ova with both male and female pronuclei were found when cumuli were present (P less than 0.05).

Animals↗
PubMed1983

In vitro maturation and fertilization of bovine oocytes are temperature-dependent processes.

Effects of temperature on bovine sperm acrosome reaction, oocyte maturation, hyaluronic acid production by cumulus cells and in vitro fertilization were studied. Viability and a true acrosome reaction of bovine spermatozoa were impaired at 40 degrees C. Temperatures lower than 35 degrees C did not enhance the acrosome reaction. However, viability between 30 degrees C-38 degrees C was not altered after 22 h of incubation. The optimal temperature for the acrosome reaction was 38 degrees C. Labeled glucosamine incorporation into glycosaminoglycans was not different among temperatures of 35 degrees C, 37 degrees C or 39 degrees C, whereas 41 degrees C caused a significant reduction (P less than 0.02). Temperatures ranging between 35 degrees C-39 degrees C had no deleterious effects on resumption and completion of meiosis, but at 41 degrees C the frequency of oocytes that progressed to Metaphase II was significantly reduced (P less than 0.0001). Ova matured at 39 degrees C had significantly higher rates of fertilization than at 35 degrees C, 37 degrees C, or 41 degrees C. Killed spermatozoa (control) had no effect on ovum activation at 39 degrees C. From these results it was concluded that events occurring prior to and during fertilization are temperature sensitive.

Acrosome↗
PubMed1982

Glycosaminoglycans in bovine cumulus-oocyte complexes: morphology and chemistry.

Bovine cumulus-oocyte complexes from small (1-5 mm) follicles were cultured for 24 h in 0.25 ml minimum essential medium supplemented with 10% fetal bovine serum and 20 microCi [3H]glucosamine. Treatment groups consisted of supplementing the culture medium with no hormone (control), 0.5 IU/ml follicle-stimulating hormone (FSH) or 10 mM 8-Br-adenosine cyclic monophosphate (cAMP). After culture, the complexes were fixed for light and scanning electron microscopy. Electron photomicrographs revealed that complexes induced to expand with FSH or cAMP contained a copious glycosaminoglycan (GAG) matrix extending between and around the cumulus cells. Control complexes did not exhibit expansion or an extracellular matrix. The radiolabeled GAG material was isolated for chemical identification. Chemical analyses included: (1) electrophoresis of GAG material, (2) electrophoresis of GAG material after enzyme or nitrous acid treatment, (3) thin-layer chromatography of GAG hydrolysates. The results from electrophoresis showed that the radiolabeled GAG co- migrated with hyaluronic acid. The GAG material was resistant to chondroitinase ABC and nitrous acid degradation but was digested by hyaluronidase. Complexes treated with FSH and cAMP incorporated higher (P less than 0.1 and P less than 0.025 respectively) amounts of [3H]glucosamine into hyaluronic acid than control cultures. Thin-layer chromatography identified the primary amino sugar of the GAG to be glucosamine. These data collectively showed that the radioactive GAG produced by bovine cumulus-oocyte complexes was hyaluronic acid.

Animals↗
PubMed1982

Release of relaxin by a nonluteolytic dose of prostaglandin F2 alpha in pregnant swine.

Ten gilts were infused intravenously for 5 min on Days 105 and 108 of gestation with 50 micrograms prostaglandin F2 alpha (PGF2 alpha) in 10 ml of saline or saline alone. Plasma concentrations of relaxin and progesterone were determined in samples taken 1) immediately before and after infusion, 2) at 10-min intervals throughout the first h postinfusion, 3) at 30-min intervals throughout the next 5 h, and 4) at 12-h intervals from Day 103 of gestation through Day 1 postpartum. Plasma concentrations of relaxin were increased immediately after infusion with PGF2 alpha and peaked within 10 min postinfusion. The peak was followed by a rapid decline in plasma relaxin throughout the remainder of the first hour following infusion. Progesterone values did not change from preinfusion levels for either treatment during this time period and did not differ between treatments for the remainder of the gestation period. When compared to controls, PGF2 alpha-treated animals were not significantly different with respect to length of gestation, duration of parturition or frequency of live births. These results indicate that exogenous PGF2 alpha can stimulate relaxin release from the corpus luteum without inducing luteolysis.

Animals↗
PubMed1982

Bilateral luteal maintenance in unilaterally pregnant pigs with infusions of embryonic extracts.

Thirty unilaterally pregnant gilts with bilateral corpora lutea received infusions three times daily into a surgically isolated, nonpregnant uterine horn from d 12 through d 19 after mating. The infusions consisted of either saline alone or embryonic extracts in saline which were either untreated, heat-treated or charcoal-absorbed. The extracts were from porcine embryos, embryonic membranes and fluids between d 16 and 25 of pregnancy. While only 20% of the gilts infused with saline alone and none of those infused with charcoal-absorbed embryonic extracts maintained pregnancy to d 19, 100 and 83% of the gilts infused with untreated and heal-treated embryonic extracts, respectively, were pregnant on d 19. Similar treatment effects were observed for the incidence of bilateral luteal maintenance. No gilts receiving infusions of either saline or charcoal-absorbed embryonic extracts exhibited bilateral luteal maintenance. However, 67% of the gilts infused with untreated embryonic extracts and 67% of those infused with heated extracts had bilateral luteal maintenance on d 19. Additionally, the weights and progesterone concentrations of corpora lutea adjacent to the infused uterine horns were not different (P less than .05) from those of the corpora lutea adjacent the to pregnant uterine horns in gilts with bilateral luteal maintenance.

Animals↗
PubMed1982

Local effects of PGF2 alpha and embryonic extracts on luteal function in swine.

Individual corpora lutea (CL) from 10 gilts were assigned to seven treatment groups. Corpora lutea assigned to group 1 were unimplanted, while those in groups 2 through 7 were given implants congealed with saline, prostaglandin F2 alpha (PGF2 alpha) vehicle, PGF2 alpha, PGF2 alpha and untreated embryonic extracts, PGF2 alpha and heated embryonic extracts or PGF2 alpha and charcoal-adsorbed embryonic extracts, respectively. Individual CL implanted with PGF2 alpha alone had a lower (P less than .05) mean weight and progesterone concentration than CL in all other treatment groups except those treated with PGF2 alpha and charcoal-adsorbed embryonic extracts. Untreated and heat-treated embryonic extracts prevented the reduction in luteal weight and progesterone concentration induced by PGF2 alpha treatment.

Animals↗