The purpose of this study was to determine the effects of PAF treatment of rabbit spermatozoa on in vitro fertilization and subsequent blastocyst formation. Rabbit spermatozoa were exposed to PAF (10-7 M ), lyso-PAF (10-7 M ), or HIS (385 mOsm/kg) for 15 min prior to insemination of ovulated oocytes. Fertilized oocytes were cultured to the hatched blastocyst stage.

Rivulus marmoratus (Cyprinodont; Aplochelidae) is the only vertebrate known to reproduce by obligate internal self-fertilization. Selfing is the ultimate form of inbreeding and leads to virtual homozygosity in approximately ten generations, so that this mode of reproduction is effectively clonal. Populations of this species consist of arrays of homozygous clones, with high clonal diversity and low representation of each clone. Males occur at low frequency (<1%) in most populations, with a few notable exceptions. Females have never been recorded.High frequencies of males have been reported on two occasions; high numbers of males were reported on the island of Curacao in the 1970's, and males comprised up to 24% of the populations sampled on several Belize Cays during 1990-91. Hermaphrodites collected from one island, Twin Cays, proved to be heterozygous at mini-satellite loci when progeny tested and DNA fingerprinted. This was evidence that recent outcrossing had occurred.Earlier experiments with Floridian clonal lines had suggested that sex in this species was thermolabile; incubation of embryos at low temperatures (19° C)) produced up to 100% males. It was suggested that this might be part of an environmental sex determination (ESD) system in this species.If the induction of males is indeed part of and ESD in this species, then it may be that the temperature at which males are induced in a particular clone will be related to the temperature regime that clone encounters in nature. Therefore, it was hypothesized that the temperature at which males are induced would be related to the geographic origin of each clone, so that clones from the cooler extremes of the range would produce males at a lower threshold temperature than clones from the more equatorial center of the range. This study used laboratory reared descendants of clones from Vero Beach, Florida, Rio de Janiero, Brazil (the extreme north and south of the range), and from several Belize barrier islands and the Belize mainland (near the center of the range) in an effort to detect differences in the production of males between clonal lines based on their geographic origin. Eggs were collected from these hermaphrodites and incubated at 26° C)C, 22.5° C), or 19 ° C), representing normal, and below average temperatures for this species. These embryos were hatched and reared to sexual maturity at which time their sex was evaluated.Incubation at 26° C) resulted in 2-17% males, incubation at 22.5° C) resulted in 6-53% males, and incubation at 19° C) resulted in 47-74% males. However, the variation in male induction between clonal lines did not correspond to a geographic hypothesis.Also, significant numbers of deformed individuals were noted, particularly among individuals incubated at the lower two temperatures. Incubation at 26° C) resulted in 0-24% deformed, incubation at 22.5° C) resulted in 6-66% deformed, and incubation at 19° C) resulted in 36-87% deformed. It is clear that development at these lower temperatures is difficult for this species, and it may be that low temperature developmental stress is not a general challenge to this species. / Master of Science

A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Medicine in the branch of Obstetrics and Gynaecology. Johannesburg, 2017 / Background Recurrent IVF failures may result from implantation defects of which a thin endometrium is often implicated. Studies show that improved endometrial thickness increases the probability of successful IVF. Objectives To evaluate the effects of transcervical instillation of G-CSF as an adjunct to IVF. The study looked at the influence of G-CSF on the endometrium and on the achievement of pregnancy. Methods A retrospective cross-sectional study of women attending Bio ART Fertility Centre, who had two or more failed IVFs previously. Results There were a total of 49 women studied with a mean age of 38.9. Mean number of previous IVFs were 3.1. Comparison between those that achieved pregnancy and those that did not showed that age was a statistically significant factor (p-value 0.0005). Mean endometrial thickness pre and post-GCSF between the groups was not statistically significant (p-values >0.05). Conclusion With the use of G-CSF we achieved a clinical pregnancy rate of 34.69% and a statistically significant overall expansion of endometrial thickness (p-value 0.0029). However we failed to show any association between endometrial expansion and pregnancy outcome. / MT 2018

No description available.

Fertilization and cleavage of bovine embryos depend not only on maternal involvement, but also on the paternal contributions that involve more than just providing the haploid male genome. Therefore, the overall objective of this project was to determine the impact of morphologically abnormal spermatozoa on fertilization, subsequent embryonic development, and embryo quality at the cellular level. Four experiments used morphologically abnormal semen samples collected and cryopreserved from four Holstein bulls before (Pre) and after a scrotal insulation (PI) period of 48 h. Zygotes were cultured for 8 d when a developmental score was assigned to each embryo; subpopulations were subjected to either the TUNEL or caspase assays to determine apoptosis. In the final experiment pronuclear decondensation for presumptive zygotes was evaluated by differential interference contrast microscopy at 3 h time intervals from 6 to 18 h post in vitro insemination (hpi). Morphological evaluation of semen samples revealed a decrease (P < 0.01) in the percentages of normal spermatozoa in the PI samples in comparison with the Pre samples for Bulls I and Bull III (74 to 22.3% and 67.7 to 0.5 %, respectively) and the scrotal insulation effects persisted from the time of cleavage through blastocyst formation for Bulls I and III and corresponded with a similar decrease in blastocyst development for PI samples in experiment 1 regardless of which semen separation method was used. Likewise, the overall pronuclear decondensation rate for the PI zygotes of Bull I and III showed no increase over time and remained predominantly at PN1 stage (1.5 ± 0.17; 1.8 ± 0.22, respectively). In contrast, the development for Bull II and Bull IV were unaffected. The embryo quality assessment revealed that the caspase intensity increased significantly for both Bull I (217 ± 147) and Bull III (229 ± 98) for the PI embryo groups compared to those of Bull II (98 ± 115) and Bull IV (90 ± 111). In conclusion, the tested separation methods used seemed inadequate in their ability to provide potentially competent sperm for IVF. The decrease in embryonic development appears to be multifaceted and related to the changes in head shape morphology and we suggest the failure in normal pronuclear formation is associated with an absence of normal decondensation of the penetrating spermatozoon. The inability to consistently measure apoptosis in early stage embryos complicates the assessment of differences in embryo quality. These observations support the hypothesis of uncompensable seminal traits in IVF with abnormal spermatozoa and provide compelling evidence that the effect of morphologically abnormal spermatozoa occurred prior to cleavage, thus is manifested during the early stages of fertilization. / Ph. D.

<p>Sperm competition, the contest between sperm from rival males for fertilizations, is an important evolutionary force shaping sperm characteristics. Theory predicts that males experiencing elevated levels of sperm competition will invest more in sperm number, size and speed. While broad support exists for the idea that elevations in sperm competition lead to increased investment in sperm production, there is mixed support for the role of sperm competition in shaping sperm size and swimming speed. In this thesis, using a combination of within-species and comparative studies, I describe how sperm competition has influenced sperm traits in fishes and critically test a number of predictions from sperm competition theory. In the marine plainfin midshipman fish (Porichthys notatus) and the fresh-water shell brooding cichlid Telmatochromis vittatus, I show that the males who experience the highest level of sperm competition had faster but not longer sperm. Instead, selection appears to have acted on sperm energetics, increasing energy production to drive sperm movement in males who experience more intense levels of sperm competition. In a comparative study using Tanganyikan cichlids, I show that males in species experiencing high levels of sperm competition (i.e. promiscuous species) had both longer and faster sperm than males of closely related species unlikely to experience sperm competition (i.e. monogamous species). I also uncovered a predicted but previously inadequately tested relationship between sperm size and speed. This relationship holds across, but not within, species and I discuss possible explanations for differences between and within species. Finally, I used directional tests of trait evolution to assess how selection acts to increase sperm swimming speed and provide evidence that the evolution of fast swimming sperm preceded the evolution of long sperm across cichlid fishes. Together, the results of this thesis show that spenn competition promotes the evolution of faster swimming spenn in fishes and highlights the importance of sperm energetics in detennining the competitive success of ejaculates.</p> / Thesis / Doctor of Philosophy (PhD)

No description available.

Short-rotation woody crops are becoming important supplies of hardwood fiber, but little is known about the early nutritional needs of these systems, especially on different site types. The study objectives were, on two young (ages 3-6) sweetgum plantations with contrasting soil types, to 1) determine the plant growth and foliar nutrition response to repeated nitrogen (N) fertilizer applications, 2) determine soil N supply, plant N demand, foliar N resorption, and soil and fertilizer uptake efficiencies, and 3) test a simple N supply model. In order to expand the findings to the range of sweetgum site types, the study objectives were also to 4) evaluate rapid methods for determining N mineralization potential, 5) characterize the soils of 14 sweetgum site types in the Atlantic coastal plain, and 6) review current N fertilizer prescriptions in forestry and recommend strategies for improvement. Two young sweetgum (Liquidambar styraciflua L.) plantations on a converted agricultural field and a pine cutover site in South Carolina were fertilized biannually with three rates of N fertilizer (0, 56, 112 kg N per ha). Fertilization doubled foliar biomass and leaf area on the cutover pine site in the years fertilizer was applied, and stem biomass increased 60%. Critical values, the N concentration required for 90% of optimum growth, is approximately 1.75%. Foliar N uptake increased at both sites when fertilizer was applied. Modeled annual soil N supply was within 20% of that measured on the two plantations even though monthly N supply was not accurately estimated. Potential N mineralization was accurately estimated with a 3-day incubation of rewetted soils that were previously dried, but not by hot salt extraction or anaerobic incubation. Across a spectrum of 14 sweetgum sites, the agricultural fields had lower mineralizable nitrogen (126 kg per ha) than the cutover sites (363 kg per ha). Current N fertilizer prescriptions are not sufficient for repeated fertilizer applications to fast-growing hardwood plantations, but simple models of soil N supply and an N-balance approach may improve prescriptions. / Ph. D.

Forest plantations in the southeastern U.S. are fertilized to increase growth on infertile, sandy soils. Nitrogen (N) and phosphorus (P) are the most common growth limiting nutrients. A key question that arises following fertilization of these soils is whether the applied fertilizer benefits only the current trees in the stand or also improves long-term site quality. The objectives of this study were to compare accumulation of N and P in the forest floor and mineral soil among unfertilized and fertilized plantations, determine soluble and residual N and P fractions and soluble carbohydrate and phenol fractions in foliage and litter, determine whether higher N in the forest floor from fertilization resulted in increased release of N from the forest floor and increased mineral soil N availability, and determine loblolly pine forest floor decomposition rate and release of nutrients in a simulated disturbance environment. Research was conducted at a 25-year old loblolly pine (Pinus taeda L.) plantation in NC (SETRES) and 13-year old loblolly pine and sweetgum (Liquidambar styraciflua L.) plantations in GA (Mt. Pleasant). Fertilization resulted in increases in mineral soil N that were likely to be temporary and not sustained following cessation of fertilization N applications. This was likely due to an inability of acidic, sandy mineral soils to retain NH4-N and NO3-N. The forest floor accumulated N due to slow release of N during decomposition. Fertilization with N results in only temporary increases in mineral soil N availability that occur during fertilizer application and from forest floor decomposition. Future changes in N availability are primarily determined by decomposition of the forest floor following a disturbance that accelerates decomposition. In contrast to N, fertilization of loblolly pine and sweetgum with P results in a long-term increase in site P availability. Fertilization with P has lasting effects by increasing mineral soil P in stable forms that can be made available for plant uptake over time suggesting increased supply of P to trees in the next rotation. Retention of P in the mineral soil was likely due to the tendency of acidic, sandy mineral soils to accumulate P in Al- and Fe-phosphates. / Ph. D.

If a landowner‘s main objective is to maximize his/her profits from planted forest investments, questions such as when and where exactly they should fertilize, thin and clearcut must be answered. We take advantage of an experiment established in 5 different states in the US South. Forest inventory data was collected for different combinations of thinning densities where some of them received fertilization. We use the Land Expectation Value methodology where our assumptions are the infinite amount of Pine rotations while costs and stumpage prices are known and constant, and markets are perfect. One of the main results we found is that fertilization has a decreasing marginal benefit on site index quality. / M.S. / If the landowner‘s main objective is to maximize profit from forest investments, questions such as when and where they should fertilize, thin and clearcut must be answered. Fertilization‘s main objective is to provide essential nutrients for tree growth. Thinnings have two main objectives: a source of revenue in the middle of the forest rotation by selling the thinned trees and secondly to open space to the residual trees so they grown in diameter and gain value. We analyze how thinning and fertilization impact forest management from an economic perspective by checking their benefits and costs to landowners. We found that for low site index, fertilization has a positive impact in the sense its benefit is greater than the fertilization application cost. For better site indices, the opposite is true. For those who want to maximize economic benefits from planted forests. we end up with recommendations of which type of thinning and fertilization should be done according to the landowner site quality.