Errata inserted. Bibliography: leaves 98-120. This study is concerned with the identification of genes related to the very early stages of meiosis when homologous pairing occurs. A cDNA library is prepared at the premeiotic interphase and prophase stages of meioses. Differential screening is used to identify and select clones showing preferential expression in anthers at early meiosis. Two selected clones are chosen for further analysis and to investigate a possible role in chromosome pairing.

Natural killer (NK) cells, lymphocytes of the innate immune system, can recognize a wide array of cells via several receptors families such as Ly49 and NKR-P1. The Nkrp1 gene family encode for C-type lectin-like receptors which can recognize their ligands, Clr, on target cells. Nkrp1 and Clr genes are intertwined in the NK gene complex and are thus inherited together. The Nkrp1-Clr genes in 129S6 and BALB/c mouse strains show significant sequence polymorphism compared to those of C57BL/6 mice while the overall gene organization and gene number are conserved. RT-PCR was utilized to study the expression of individual Nkrp1-Clr genes. In situ hybridization was performed to validate expression results from RT-PCR, as well as to verify the cell types in which Nkrp1-Clr genes are expressed. Surprisingly, our expression studies reveal an interesting pattern of expression of Nkrp1 and Clr genes not only in lymphoid tissues but also in the epithelial cells of the intestine, kidney, eye and lung, the myocytes of the heart and skeletal muscle, and possibly some endothelial cells, indicating novel functions of NK cells in these tissues.

Climate change is rapidly altering natural ecosystems. Plastic and adaptive responses to climate change (i.e., range shifts and phenology) have been widely noted across taxa. However, the effects of climate change on evolutionary processes such as interspecific gene flow (hybridization) are less well known. In this study, we quantified hybridization rates in response to experimental manipulations of rainfall, an important dimension of global change. We used rain-out shelters in the field and quantified rates of hybridization between two congeners, Helianthus annuus (common sunflower) and H. petiolaris (prairie sunflower). We found that H. annuus maternal plants produced hybrid progeny more than H. petiolaris maternal plants, with a trend for decreased rates of hybridization with increased soil moisture (when rain-out shelters were absent). The relative number of open inflorescences of each species predicted hybridization rates. Thus, this study demonstrates how changing environmental conditions, specifically precipitation, could influence hybridization rates.

Speciation lies at the heart of evolution and the study of reproductive barriers allows a better understanding of the different steps leading to the complete isolation of two species. Pre-mating (behavior tactics, habitat or food divergence, phenotypic divergence and assortative mating) and post-mating, post-zygotic isolation barriers (selection against unfit hybrids) are well studied in numerous species, but little is known about what is happening between insemination and fertilization (post-mating, pre-zygotic isolation barriers). In this study, we chose the well-studied population of pied and collared flycatchers (Ficedula hypoleuca and F. albicollis) of the hybrid zone of Öland, Sweden, to investigate possible patterns of gamete divergence between these two closely related species. We compared sperm morphology between the two species and their hybrids, analyzing traits that are thought to play an important role in the fertilization success of the males. We did not detect any divergence in sperm morphology between the two species, but we report an extreme reduction of sperm production in hybrid males, as well as spermatogenesis dysfunctions and particularly high rates of extra-pair young in the nests of hybrid males.

Iridovirus infections have led to serious economic loss in the aquaculture industry in Kaohsiung County as well as the whole Southern Taiwan region. Identified susceptible host species in this region includes hybrid grouper (Epinephelus hybrid), giant seaperch (Lates calcarifer), largemouth bass (Micropterum salmoides), king grouper (Epinephelus lanceolatus), spotted butter fish (Scatophagus argus), yellow-wax pomfrat (Trachinotus blochii), goldlined seabream (Sparus sarba), humpback grouper (Chromileptes altivelis), Mangrove red snapper (Lutjanus argentimaculatus). In this study, a diagnostic PCR primer pair CY15n-F/CY15nR, and its nested primer pair RY16-F/RY16-R, were designed and applied to amplify virus-specific products of 1339 bp and 305 bp, respectively. This primer set did not amplify products from lymphocystis disease virus, largemouth bass virus, or healthy control fish DNA. This sensitive technique can detect the presence of 50 fg plasmid with viral DNA insert in the presence of 100 ng/£gl host DNA, or 0.05 fg DNA from infected fish. Comparing sequences of CY15 fragment, ATPase gene, predicted major capsid protein and partial DNA polymerase genes among iridoviruses, it is suggested that the viruses found in this area should be classified as the Megalocytivirus of Iridoviridae. These viruses are clearly different from the Ranavirus, another fish-pathogenic iridovirus. Those iridoviruses can be classified into two genotypes: the CY630 type, which is the Taiwan grouper iridovirus; and the CY113 type, which is similar to red seabream iridovirus (RSIV). The identity in CY15 fragment sequences is about 91%. Microscopically, enlarged cells can be found in organs of infected fishes. They appear in the spleen, head kidney, and trunk kidney in infected groupers. The enlarged cells may be relocated from other organs. In giant seaperch, the enlarged cells appeared in the above mentioned organs, and also in the digestive tract and the heart. Two kinds of the enlarged cells in grouper can be distinguished by their H&E staining properties: the basophilic and the eosinophilic enlarged cells. The result from in situ hybridization and electron microscopy suggest that the viruses only appear in the basophilic enlarged cells. Both nucleus and cell volume increase in basophilic enlarged cells, while only the cell volume increases in the eosinophilic enlarged cells. The viruses appeared first in the nuclei of the basophilic enlarged cells, after the mid-phase of the infection they distributed into the whole cells. Judging from the results of phagocytosis, acid phosphatase activity and the ultrastructure of infected cells, it is suggested that this target cell is macrophage or monocyte. The viral capsid is assembled in the viromatrix, and the virogenic stroma can be either ring-shped or disc-shaped. The diameter of mature virus is 120-130 nm from side to side, or 160-170 nm from apex to apex. The electron-lucent space between the capsid and the envelope is about 20-50 nm. The virus particles can be found in (1) lysosome-like vesicles in the cytoplasm, if the host cell still has its nucleus; or (2) the viromatrix, When the host nucleus is dissolved or only has some vestige nuclear membrane left.

The sponge Cinachyrella australiensis (Demospongiae: Spirophorida) is widely distributed in Indian ocean, West Pacific ocean, and Australian waters. It also can be found in the intertidal pools of Wun-Li-Ton in southern Taiwan. The sponge can propagate asexually by budding. According to the previous studies, this sponge was suspected to be symbiotic with sulfur-oxidizing chemoautotrophic bacteria. How the generation do obtain this symbiont is still unknow. In this study, PCR was used to amplify the DNA extracted from buds and sponges to obtained the 16S rDNAs. A total of 20 clones from each bud and mature sponge samples were randomly selected and sequenced. The results indicated that the major symbiotic bacteria constitute 65¢H of the clones derived form the mature sponge and 15¢H from the buds. The dominant symbionts contain RubisCO gene and are related to the sulfur-oxidizing chemoautotrophic bacteria, associated with the tube worms of the deep sea hydrothermal vents. The location of the sulfur-oxidizing chemoautotrophic bacteria was observed by fluorescence in situ hybridization (FISH). It was found that the sulfur-oxidizing chemoautotrophic bacteria were intracellular symbiosis within the cells of cortex, archaeocytes of mesoglial, and bud. Similar results were also observed at the junction of a developing bud and mature sponge. Apparently, the symbionts are transmitted from sponge to bud vertically. Furthermore, in this study, we also found several other intracelluar symbionts besides the major symbiotic bacterium,some of them are autotrophic in nature.

Recent studies have discovered that LPS-treated Sprague-Dawley rats induced a reduction (phase I), followed by an augmentation (phase II), and decrease again (phase III) in the power density of the vasomotor component (0-0.8 Hz) in systemic arterial pressure (SAP). It was reported that the vasomotor components were related to the brain stem, even closely related to the rostral ventrolateral medulla (RVLM). But the molecular mechanism involved in the death progression of rat brain stem is mostly unknown. We used suppression subtractive hybridization (SSH) and library construction to find differentially expressed genes between phase I and phase II of LPS-treated RVLM. At present, we have found some genes that are differentially expressed between phase I and phase II of LPS-treated RVLM. Some genes are up-regulation expression and others are down-regulation expression. Thus, these genes may be involved in the molecular mechanism of the death progression in the rat brain stem.

Thesis (Ph. D.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains xi, 94 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 78-89).

Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains vi, 41 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 39-41).

Thesis (Ph. D.)--University of Hong Kong, 1988.