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The gonad of the snail Helix aspersa is innervated by a branch of the intestinal nerve. Here it is demonstrated that nerve stimulation causes peristaltic contractions and the acceleration of cilia beating in the proximal part of the hermaphroditic duct. Acetylcholine and serotonin induced peristaltic contractions when applied without nerve stimulation. As well, serotonin induced the acceleration of cilia beating. The neuropeptide FMRFamide caused dilation of the hermaphroditic duct. Pharmacological blocking of acetylcholine and serotonin receptors with concurrent nerve stimulation induced a dilation similar to that caused by FMRFamide application. It is suggested that all three transmitters are released from intestinal nerve terminals to facilitate oocyte transport during ovulation. Nerve stimulation induced an increase in gamete transport rates. Because several candidate chemical messengers failed to induce ovulation when injected into the circulatory system, Helix aspersa appears to initiate ovulation differently from related species. Whereas Aplysia and Lymnaea use hormones, Helix apparently signals ovulation via the intestinal nerve.

Graduation date: 1998

To determine whether membrane-related events may be involved in attenuated luteal function after gonadotropin-releasing hormone (GnRH) administration, corpora lutea (CL) were removed from 10 beef heifers on day 7 of the estrous cycle after i.v. injection of GnRH or saline on day 2 of the cycle. Luteal slices were incubated with saline (control), luteinizing hormone (LH) or 8-bromo-cAMP for 2 h. In vivo administration of GnRH reduced LH and cAMP-stimulated progesterone production by tissue (p<0.01), but basal progesterone production was not affected (p>0.05). Luteal adenylyl cyclase activity did not differ between saline and GnRH-treated animals (p>0.05). Results of this experiment suggested that GnRH-induced alteration of bovine luteal function may be due to an effect distal to the point of cAMP accumulation. To explore further the effect of GnRH on luteal cell function, 10 heifers were injected with saline or GnRH and CL removed as above. Dissociated (mixed) and small luteal cells (SC) were cultured overnight, then incubated for 2 h with medium alone (control), LH or cAMP. In vitro treatment with LH and cAMP increased progesterone in the medium relative to controls (p<0.01), however, there was no effect of GnRH injection on progesterone production (p>0.05) nor in the percentage of large cells (LC) present in the mixed cell cultures (p=0.95). It has been previously found that the ratio of LC to SC increases in GnRH-treated animals. Many LC can be ruptured during dissociation of the CL, and it is possible that this procedure altered the number of LC, such that any differences that may have existed between the saline and GnRH-exposed CL were minimized. These data suggest that differences in the LC to SC ratio may indeed account for attenuated luteal function after exposure to GnRH. To examine if early administration of GnRH alters response of the CL to prostaglandin (PG) Fav beef heifers were injected with saline or GnRH on day 2 of the cycle (n=4/group), then injected with PGF[subscript 2��], on day 8 and the CL removed 60 min later. Blood samples were collected for oxytocin (OT) analysis at frequent intervals after PGF[subscript 2��], injection and for progesterone at 0 and 60 min. Induction of the early response gene c-jun or release of OT by PGF[subscript 2��], was not altered by GnRH injection (p>0.05). Injection of PGF[subscript 2��], decreased serum progesterone by 60 min post-injection (p<0.05), but was also unaffected by GnRH (p>0.05). These data support the hypotheses that c-jun expression and OT release are involved in PGF[subscript 2��]-induced luteolysis, but early administration of GnRH did not affect these processes. / Graduation date: 1996

Two studies were conducted to determine if 7-d MGA or PRID treatment initiated on d 17 of the estrous cycle altered: 1) follicular development, 2) estradiol-17β (E2) and progesterone (P4) concentrations, and 3) patterns of release of luteinizing hormone (LH). In both studies, Angus, Angus x Holstein or Holstein cows 2 to 6 yr of age were randomly assigned to receive either MGA (.5 mg⋅hd⁻¹⋅d⁻¹; n = 23) or PRID (n = 26) for 7 d or to serve as untreated controls (n = 14). Real time, B-mode ultrasound, equipped with a 7.5 mHz linear-array transrectal transducer, was used to conduct daily ovarian scans beginning 3 (Study 1) or 9 d (Study 2) after onset of estrus. Jugular venous blood samples (45 ml) were collected coincident with ovarian scans. In study 2, cows were fitted with indwelling jugular catheters 17 (Control, MGA and PRID), 20 and 23 d (MGA and PRID) after onset of estrus and blood samples were collected at 15-min intervals for 6 h for determination of LH. Interestrus interval was extended (P<.05) for 3 to 5 d in MGA-treated cows exhibiting two or three dominant follicles (classified as MGA-2 and MGA-3, respectively) or PRID-treated cows compared to controls exhibiting two or three dominant follicles during the estrous cycle (control-2 and control-3, respectively). Forty-four percent of MGA-treated cows ovulated the dominant follicle present at the beginning of MGA treatment. In both studies, days from detection of the ovulatory follicle until ovulation were greater (P<.01) in MGA-2 and control-2 cows than control-3, MGA-3 and PRID cows. Diameter of the ovulatory follicle was greater (P<.01) 9 d before estrus and growth rate of the ovulatory follicle was less (P<.02) in MGA-2 and control- 2 cows than control-3, MGA-3 and PRID cows. Serum P4 decreased 3 d earlier (P<.02) during the estrous cycle of MGA-2 and control-2 cows than control-3, MGA-3 and PRID cows. Serum E2 was greater (P<.01) 7 d before estrus in MGA-2 cows than all other treatment groups. Changes in mean and baseline LH concentrations and amplitude of LH pulses on d 17, 20 and 23 after onset of estrus did not differ (P>.10) among treatments. Luteinizing hormone pulse frequency was greater (P<.03) on d-20 after onset of estrus in MGA-2 cows than MGA-3 and PRID cows (4.3 ± .6 vs 2.6 ± .3 and 3.2 ± .4, respectively). In addition, LH pulse frequency did not differ (P>.10) 17 or 23 d after onset of estrus among treatments. In conclusion, MGA treatment extended the dominance phase of development of ovulatory follicles, which resulted in the premature increase in serum E2 and frequency of LH release, whereas the dominant follicle present at the beginning of PRID treatment underwent atresia and another preovulatory follicle developed. / Ph. D.

Conclusion. Taken together, paternal factors carried in ASG secretion affect genomic imprinting of developing embryos. The outcome of research work described here deepens our understanding of the role of ASG in maximizing reproductive performance mediated by regulating the epigenetic marks of the genome and in particular the imprinted genes. / Introduction. Our previous in vivo studies in golden hamster have shown the accessory sex glands (ASG) secretion facilitate the development of embryos to term but the underlying mechanism is still not clear. Since the deleterious effect caused by the lack of sperm exposure to ASG secretion is heritable to developing fetus and even after birth, we hypothesized that the paternal factor carried in ASG secretion may change the epigenetic regulation and in particular the imprinted genes of embryonic genome. / Materials and methods. Golden hamster and ICR mouse were used in this study. Hamster is a well-established animal model to study the effect of individual ASG but the genetic background of hamster is poorly known. To verify the specificity of our molecular probe and antibodies used in hamster, a mouse model was also established. Five groups of male hamsters and two groups of male mice were established by surgical treatment. In hamster, (SH) sham-operated, (VPX) ventral prostate-removed, (TX) all ASG-removed, (VPVX) castrated with ASG-removed except ventral prostate and (VX) castrated with intact ASG were established. In mouse, SH and VPX were established. In single-mating of hamster, male was copulated with female at estrus for 15 min. In double-mating of hamsters, female mated with each male for 10 min each. In single-mating of mouse, male was caged with female for 1 h. Epididymal sperm, uterine sperm, fertilized oocytes, pre-implantation embryos and fetuses at 13 days gestation (E13) were collected. Global DNA methylation of sperm, fertilized oocytes, early embryos and E13 fetuses were investigated by indirect immunofluorescence and DNA dot-blot using antibody against methylated DNA. Using the same technique, histone acetylation at lysine 5 residue was detected in male pronuclei of fertilized oocytes, protamine 1 and 2 content were detected in sperm, DNA methyltransferase 1, 3a and 3b activities were detected in early embryos. The crown-rump length and weight of fetuses were measured. Morphology was also examined under scanning electron microscope. Two sets of co-ordinately regulated but oppositely expressed imprinted genes Igf2/H19 and Dlk1/Gtl2 were investigated. H19 differentially methylated region (DMR) and Gtl2 promoter were examined by bisulfite sequencing in sperm and E13 fetuses. Expression of Igf2 and Dlk1 were examined by in situ hybridization and real-time PCR in pre-implantation embryos and E13 fetuses. / Results. Uterine sperm in VPX and TX groups showed no change of DNA methylation level and protamine 1 and 2 content. Fertilized oocytes in VPX and TX groups showed similar DNA methylation level as SH group in both hamster and mouse. Histone hypoacetylation was observed in male pronuclei of hamster but not in mouse. Early embryos in VPX and TX groups showed abnormal level of DNA methylation and Dnmt3b during embryo development in hamster. Replenishment of ASG secretion to sperm from VPX and TX group by double-mating restored the DNA methylation level to normal in early embryos. E13 fetuses of VPX and TX groups in hamster and VPX group in mouse showed DNA hypomethylation. E13 fetuses of VPX group in hamster showed increase in average crown-rump length and body weight with larger variations between individuals. One E13 fetus of VPX group in mouse showed polydactyly and malformation in the head. Real-time PCR showed abnormal expression of Igf2 and Dlk1 in both pre-implantation embryos and E13 fetuses of VPX and TX groups. Bisulfite sequencing showed hypermethylation of H19 DMR in VPX and TX groups of hamster and hypomethylation of Gtl2 promoter in VPX group of mouse. / "August 2007." / Adviser: Pak Ham Chow. / Source: Dissertation Abstracts International, Volume: 69-08, Section: B, page: 4739. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 194-224). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.

Graduation date: 1993

The Bureau of Land Management (BLM) maintains a growing number of feral horses on public rangelands. With population growth rates as high as 22% annually, herds are exceeding their carrying capacity and millions of dollars are spent maintaining captured horses in holding facilities awaiting adoption. To manage the feral horse population, the BLM is seeking a contraceptive that is safe, can be remotely delivered, requires only a single administration and is effective for several years. Contraceptive strategies have been developed for feral horses that include hormone implants, chemical intrauterine devices, and immunocontraception. Porcine zona pellucida (pZP) immunocontraceptive vaccines have shown great potential for providing safe, long-term contraception in feral horses. ImmunoVaccine Technologies (Halifax, Nova Scotia, Canada) has developed a liposome encapsulated pZP formulation known as SpayVac™ (SpayVac), which after a single-dose provides multi-year contraceptive efficacy. In a continued effort to optimize the acceptability and efficacy of SpayVac, ImmunoVaccine Technologies developed alternative adjuvant preparations using either killed Mycobacterium butyricum (Modified Freund's Adjuvant; MFA) or a proprietary non-Mycobacterium based adjuvant (IVT) that are proposed to have less of the undesirable side-effects associated with Mycobacterium tuberculosis. Therefore, the objective of this research was to evaluate SpayVac in different adjuvant formulations for efficacy of contraception as measured by pZP titers and estrous cyclicity in treated mares. Domestic mares (n=28) were randomly assigned to four treatments (7 mares per treatment): adjuvant alone or saline (Control) or SpayVac vaccines in one of three adjuvant preparations: IVT or MFA in either an aqueous (MFA aq) or non-aqueous (MFA non-aq) suspension. Pre-immune blood samples were collected from each mare and mares were injected in the neck with a single injection of the Control or SpayVac. Subsequent blood samples were collected at weekly intervals for 26 weeks. Sera were analyzed for pZP titers and progesterone using ELISA. At the conclusion of the study, ovaries were recovered by ovariectomy (16 mares) or at necropsy (12 mares) for histologic analysis and collection of morphometric data and oocytes. Titers for pZP were greater (P<0.05) in IVT and MFA mares compared to Control mares and for MFA compared to IVT mares. Mares vaccinated with MFA aq had greater (P<0.05) pZP titers at 2 weeks post-injection compared to mares injected with IVT or MFA non-aq and at 3 weeks post-injection compared to mares injected with IVT. MFA non-aq mares had greater (P<0.05) pZP titers at 6 weeks post-injection compared to IVT mares and, although not significantly different, titers in MFA non-aq mares remained greater during weeks 8, 10, 14, 18 and 22 compared to IVT and MFA aq mares. Mean serum progesterone concentrations were greater (P<0.05) in Control compared to MFA non-aq mares. Mean ovarian weights, oocyte diameters, zona pellucida thicknesses and the number of horse sperm bound to oocytes recovered from vaccinated mares were greater (P<0.05) in Control mares compared to IVT and MFA mares. As judged by pZP titers and serum progesterone, these results suggest that SpayVac suspended in the MFA non-aqueous formulation exerted the greatest contraceptive effects in treated mares. This preparation of SpayVac may meet the criteria cited by the BLM for their most desirable immunocontraceptive. / Graduation date: 2012

Thesis (Ph. D.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), February 2011. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 136-146). / The environmental cues for synchronous reproduction were investigated for two highly abundant, ecologically important crustacean species: the temperate acorn barnacle, Semibalanus balanoides, and the tropical terrestrial crab, Gecarcinus quadratus. Larval ecology of these two species was also studied to determine potential sources of larval mortality and recruitment success. High-frequency observations revealed that early-stage larval abundance of S. balanoides was related to storms, and possibly turbidity. Field observations and experiments studied the effect of turbidity and phytoplankton on larval release response. Release coincided with increased turbidity at three sites along the northeast coast of the United States. A three-year time series of phytoplankton and zooplankton data showed that larval release was not consistently related to phytoplankton abundance (total or single species). When gravid barnacles were exposed to phytoplankton or synthetic beads, they released in response to both, suggesting that presence of particles is more important than identity of particles. Feeding experiments showed that adult cannibalism on newly released larvae is lower in highly turbid conditions. It is suggested here that S. balanoides synchronizes its reproduction with the onset of phytoplankton blooms, but turbidity may fine-tune the timing if it provides predation refuge for larvae. Adult G. quadratus females undertake synchronized breeding migrations to the ocean after the first rains of the rainy season, presumably when the risk of desiccation is lowest. They wait for darkness and an ebbing tide before releasing their eggs into the water. First-stage zoeas have dark pigmentation, long dorsal and rostral spines, and a pair of lateral spines. Hatching in darkness may help zoeas avoid predation from planktivorous diurnal fish, and the zoeal spines may deter predation from planktivorous nocturnal fish. In the laboratory, a G. quadratus zoea reached the megalopa stage in 21 days. A mass migration of megalopae and juveniles out of the water was observed 30 days after adult females released their eggs. Plankton pump samples taken near the island suggest that zoea abundance and distribution may be related to the phase of the internal tide. Synchronous reproduction in these two species appears to be the result of predator avoidance behaviors. / by Joanna Gyory. / Ph.D.

The resident feral cat (Felis catus) population on the University of KwaZulu-Natal (UKZN), Howard College campus (HCC) in Durban, South Africa was studied from March 2004 to November 2005. This study was initiated as the HCC is an registered as an urban conservancy and so should be removing alien invasive flora and fauna and conserving the indigenous biodiversity of the campus. This research was undertaken to assist with recommendations for the control and management of feral cats on the HCe. A survey to determine public perceptions and opinions regarding the feral cats was conducted among various communities on the campus. Feral cats from the resident population on the HCC were trapped and fitted with radio-collars in order that their home range sizes and distribution could be determined. Monthly census counts were also carried out in an attempt to calculate population densities of the feral cats on campus, while data on behaviour patterns was collected opportunistically throughout the study period. The survey showed that two extreme views existed on campus regarding the presence of feral cats. The university is a registered conservancy which some feel is no place for this exotic species. However, it is also situated within an urban surrounding and there are some cat enthusiasts among the public who feel that resources should be provided for the feral cats, both nutritionally and financially. While many people were unaware that the feral cats were a cause for concern on the HCC, the majority concluded that a management policy needed to be adopted to control feral cat numbers. Most were against the suggestion of eradicating the cats and strongly agreed with the implementation of a university funded feral cat IV sterilising and feeding programme. Feeding the feral cats, however, needs to be stringently controlled. In this study, the availability of an abundance of food resources was shown to be the primary influencing factor for home range size, cat distribution and population densities. It also had an overriding effect on the feral cats' behaviour patterns and activity levels. Once these had been initially established, other factors such as human activity, reproductive status and gender then came into play. Distribution of the feral cats around campus was not homogenous, and densities differed according to areas on campus. Highest cat densities were recorded in those areas on the HCC where permanent cat feeding stations had been established (usually the developed areas on campus), while no feral cats were sighted in the Msinsi Nature Reserve, a natural bush area on campus were no food resources (other than prey species) is available. Home range sizes of the feral cats were relatively small with a considerable amount of overlap between and within the sexes. There were also no seasonal differences in range sizes and diurnal ranges were only marginally smaller than nocturnal range sIzes. In terms of behaviour, the HCC feral cats were generally inactive, with passive behaviour such as lying down and sitting being most often observed. Although hunting activity was very rarely witnessed, the combined effects of feral cats supported at high densities by supplemental feeding may exert predation pressures that could be detrimental to both local prey and predator populations. Little social interactions were observed by the cats on the HCC. Other studies show that competition is greatly reduced if food is available in abundance and there is no need for territorial disputes if both food and a potential mate are located in close proximity. In the present study, this also means that immigrating feral cats from surrounding neighbourhoods are tolerated; another factor contributing to the increase in feral cat numbers on the campus. These findings suggest that the feral cat population on the HCC is being maintained at higher population densities than would be expected and management initiatives are needed to control the feral cat population at a minimum density through a sterilising and low key feeding programme so that it is acceptable to all concerned parties. However, the decisions need to favour the status of the HCC as a conservancy in an urban area as well as consider the well-being of the students and staffmembers in a public place. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.