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Comparisons Of Spontaneous Mutation Rates And Estimates Of Numbers Of Cell Divisions In The Germlines Of Three Metazoans., Joni Boncille Drost

LSU Historical Dissertations and Theses

Germline mutation rates measured per generation per locus in three species of Metazoa are used to address questions of the constancy of mutation rates per generation, per year and per germcell division. Null mutation rates per generation are: 3.6 $\times$ 10$\sp{-6}$ for human X-linked disease, 8.9 $\times$ 10$\sp{-6}$ for Specific Locus Test (SLT) in male mice, 3.2 $\times$ 10$\sp{-6}$ for SLT in female mice, 8.0 $\times$ 10$\sp{-6}$ for SLT in male Drosophila melanogaster (D.m.), 1.6 $\times$ 10$\sp{-6}$ for SLRL test in male D.m. and 2.0 $\times$ 10$\sp{-6}$ for SLRL test in female D.m. They were found to be very similar …

Interaction Between Hydrodynamics And Sediment Topography On Meiofaunal Abundance And Distribution., Bin Sun

LSU Historical Dissertations and Theses

The objective of this dissertation was to investigate the small-scale spatial and abundance patterns of meiofauna and their relationship with sediment microtopography and hydrodynamics. Meiofauna are known to be aggregated at small spatial scales. A study was first undertaken to determine, how patchiness differed over seasons and habitats. Significant small-scale aggregations were remarkably consistent across different seasons and habitats for all abundant copepods of an intertidal mudflat. Spatial autocorrelation analysis showed that the abundance of copepods was autocorrelated at short distances (cm scale) on all sample collecting dates, indicating a consistent spatial pattern. Small-scale variation contributed heavily to the components …

A Multi-Scale Analysis Of The Population Ecology Of A Temperate Reef Fish, Phillip S. Levin

Doctoral Dissertations

Using field experiments and descriptive analyses this study investigated the significance of larval settlement and post-settlement processes to populations of cunner, Tautogolabrus adspersus. At small spatial scales there was no relationship between the density of new recruits and the percent cover of kelp, foliose algae and branching algae. Crustaceans and mussels were preferred found items of juvenile cunner, and significantly greater numbers of isopods, amphipods and newly settled mussels were present in patches where fish were present than in randomly selected patches.

Experimental and correlative analyses demonstrated that variation in recruitment could not be explained by the presence of conspecifics. …

Effects Of Hematopoietic Neoplasia On Physiological Processes In The Soft-Shell Clam, Mya Arenaria (Linne), Mary-Susan Potts

Doctoral Dissertations

Mya arenaria (L.) is susceptible to the disease, hematopoietic neoplasia (Hn), in which atypical cells invade the blood and connective tissue of the clam's organs. In this study impacts of Hn on the reproductive and excretory systems were examined in clams collected from New Bedford Harbor and Little Buttermilk Bay, Buzzards Bay, MA.

The relationships between Hn seasonality and reproduction were evaluated from fresh blood samples and histological analysis of gonads. Both clam populations had biannual reproductive cycles with spawnings in the spring and fall. Hn prevalence exhibited some seasonality with maxima in the fall and late winter-early spring. Reproductive …

The Characterization Of The Orb Web Of Argiope Aurantia (Araneae: Araneidae) With Emphasis On The Major Ampullate Silk, Cathy Rose Tugmon

Doctoral Dissertations

The orb web of Argiope aurantia was partitioned into a water-soluble and insoluble fraction. The water-soluble fraction was composed of low molecular weight (LMW) molecules ($<$5 kDa) and middle molecular weight (MMW) molecules (14.3 kDa-29 kDa). Choline was one of the principal components of the LMW molecules. This study demonstrated that spiders, like many insects, are unable to synthesize choline from glucose. Attempts to sequence one of the purified MMW proteins were unsuccessful due to the blockage of the N-terminus.

The major emphasis of this research centered on the major ampullate silk of Argiope aurantia. Attempts were made to characterize this silk, both by direct amino acid sequencing and inference from the sequence of a cDNA library clone for one of the major ampullate silk proteins.

To isolate the progenitive silk from the lumen of the major ampullate gland, it was first necessary to inhibit the spider proteases which are known to cleave silk. …

Silk Use During Proecdysis In The Spider Araneus Cavaticus (Araneae: Araneidae), Mark Anthony Townley

Doctoral Dissertations

Major ampullate (MaA) and minor ampullate (MiA) silk glands of juvenile Araneus cavaticus were examined by dissection at various times relative to ecdysis. Several days before ecdysis the single, larger pairs of MaA and MiA glands (termed 'primary' MaA and MiA glands) become non-functional and remain so until ecdysis. Nevertheless, proecdysial spiders are able to draw ampullate fibers due to the presence of smaller pairs of MaA and MiA glands (termed 'open secondary' MaA and MiA glands) which are functional at this time. It appears that these open secondary MaA and MiA glands are intended for use only during proecdysis. …

Connexin Gene Expression And The Control Of Gap Junction Assembly In Preimplantation Development, Gunnar Valdimarsson

Digitized Theses

Gap junctional communication in preimplantation mouse embryos was explored by investigating: (1) the expression pattern of the connexin (Cx: gap junction protein) multigene family in maturing mouse oocytes and preimplantation embryos; (2) the relative role of Cx43 in gap junctional communication in embryos; and (3) the control of the acquisition of gap junctional coupling.;Both Cx43 and Cx32 transcripts were detected in maturing oocytes but these transcripts declined to undetectable levels shortly after ovulation. Cx43 transcripts were detected again at the 4-cell stage and accumulated steadily thereafter to reach a maximum in blastocysts. Cx26 and Cx46 transcripts could not be detected …

The Relationship Between Wetland Productivity And The Distribution Of Breeding Mallards, Black Ducks, And Their Broods: Historical And Spatial Analysis, Michael Todd Merendino

Digitized Theses

During the last 50 years mallards have increased dramatically in southern Ontario and have completely replaced black ducks in many areas. In northern Ontario, black duck densities appear stable at present, however, mallard densities now exceed 60 pairs/100 km{dollar}\sp2{dollar} in many areas. I examined historical and spatial distributions of mallards and black ducks in Ontario in relation to water chemistry and physical habitat characteristics. My objectives were to determine (1) if mallards invaded the most fertile wetlands, and (2) if mallards replaced black ducks on the most productive wetlands.;I used Canadian Wildlife Service survey data (1971-87) to define 7 wetland …

The Reproductive Ecology Of Convict Cichlids In Costa Rica, Brian Douglas Wisenden

Digitized Theses

Convict cichlids (Cichlasoma nigrofasciatum) form monogamous pair bonds and have cooperative biparental care of their eggs, larvae and fry for up to six weeks. This fish is widely used in laboratory studies as a model of biparental care. However, very little is known of its habits in its natural habitat. I studied four natural populations of convict cichlids, in 'pool' and 'stream' habitat, in Costa Rica during the long dry season, December to June in 1990 and 1991. The number of pairs guarding broods increased from December to a peak in mid-March, then rapidly declined. Twenty-eight percent of 175 males …