The underwater optical climate of Lake Texoma was measured at eleven fixed stations from August 1996 to August 1997. Secchi transparency and submarine photometry characterized seasonal and spatial values of secchi depth (SD), vertical attenuation coefficient (η''), and depth of euphotic zone (Zeu). Indices of Zeu:SD and η'' × SD were compared with universally applied values derived from inland and coastal waters. Turbidity explained 76% of the variation (p = 0.0001) of η'' among water quality parameters, including chlorophyll-α. Using a spectroradiometer, spectral signatures of chlorophyll-α and turbidity were located. Stations with low turbidity exhibited a distinct green reflectance peak around 590-610 nanometers, indicating presence of chlorophyll-α. Stations with high turbidity exhibited a reflectance peak shift towards the red spectrum, making it difficult to detect the chlorophyll signature. Derivative analysis of the reflectance signal at 590-610, and 720-780 nanometers allowed discrimination of this chlorophyll signature from those of turbidity (0.66 ≤ r^2 ≤ 0.99).

An in vitro system of generating protoplasts from their callus cultures was established. The friable callus was more productive in terms of producing protoplasts than the green compact callus. The concentration of the various cell wall degrading enzymes had an effect on the viability of the protoplasts in the medium. The protoplast system developed from the experiments was stable and could be used for the transformation experiments of Albizia lebek and for other plant improvement practices.

This research utilized population genetic analyses (protein starch-gel electrophoresis and DNA sequencing of the cytochrome b mtDNA gene), host-parasite specificity (lice coevolution), remote sensing of satellite data, and geographic information systems (GIS) to characterize newly discovered populations of pocket gophers (genus: Geomys) in Arkansas. These populations are isolated and occur in seemingly unsuitable habitat in the Ozark Mountains of Arkansas. Analyses of electrophoretic and ectoparasite data suggested the populations in the Ozark Mountains represented isolates allied to Geomys bursarius, a species not known to occur in Arkansas. Comparison of mitochondrial DNA sequence data of the cytochrome b gene with that of other taxa and morphometric analyses confirmed that these populations are most closely allied to G. bursarius occurring to the north in Missouri. Moreover, these mtDNA sequence analyses indicated a degree of differentiation typical of that between other subspecies of pocket gophers. Therefore, these populations represent a distinct genetic entity in an intermediate stage of speciation and should be designated as a new subspecies, Geomys bursarius ozarkensis. Molecular clock analysis revealed a time of lineage divergence for this new subspecies as approximately 511,000 YBP. Due to the isolated nature and limited distribution of this subspecies, an evaluation of critical habitat …

In the United States, biodiversity impact assessment has historically received little attention. Responding in 1993, the Council on Environmental Quality (CEQ) released guidelines on incorporating biodiversity into environmental impact assessment under the National Environmental Policy Act of 1969. The objectives of the study here were to identify the level of documentation of biodiversity impact assessment in sample Environmental Impact Statements (EISs); identify whether in the years following the release of 1993 CEQ guidelines any significant changes have taken place in assessment of biodiversity; identify deficiencies, and if the need exists, formulate appropriate recommendations and approaches for addressing biodiversity in EISs. The study involved a systematic review of 30 EISs published since the release of CEQ guidelines, and five EISs published prior to it. The review involved answering a series of standard questions, which attempted to ascertain the level of biodiversity impacts included in each impact statement. Trends in approaches to biodiversity impact assessment were investigated and deficiencies summarized. The analysis resulted in a series of recommendations for improving the manner in which biodiversity impact assessment can be approached.

Spontaneously active primary cultures obtained from dissociated embryonic medial medulla tissue were grown on microelectrode arrays for investigating burst patterns and pharmacological responses of respiratory-related neurons. Multichannel burst rates and spike production were used as primary variables for analysis. Pacemaker-like neurons were identified by continued spiking under low Ca++/high Mg++conditions. The number of pacemakers increased with time under synaptic blocking medium. Sensitivity to CO2 levels was found in some neurons. Acetylcholine changed activity in a complex fashion. Curare, atropine and gallamine modified ACh effects. Eserine alone was ineffective, but potentiated ACh-induced responses. Norepinephrine caused channel-specific increases or decreases, whereas dopamine and serotonin had little effect at 30 μM. GABA and glycine stopped most spiking at 70 μM. Developmental changes in glycine sensitivity (increasing with age) were also observed. It is concluded that pacemaker and chemosensitive neurons develop in medial medulla cultures, and that these cultures are pharmacologically histiotypic.

The nucleotide sequence for the pDKl TOL plasmid region encoding toluate-1,2-dioxygenase (Xy1XYZ, TO) was determined. TO is the first enzyme in the meta-cleavage operon, responsible for the conversion of toluates and benzoates to their carboxy-substituted diols. DNA sequence analysis revealed the presence of three open reading frames (ORF). The three ORFs correspond to xylX (1353 bp), xylY (486 bp) and xylZ (1008 bp), encoding predicted protein products of 51370 Da, 19368 Da and 36256 Da, respectively.

Advanced laboratory techniques for Microbial and Molecular Biology at the graduate level are presented in this thesis. The procedures for the laboratory experiments are set forth in detail. This laboratory is conducted as two parts, each by a different professor. Part 1 covers the experiments conducted by Dr G.A.O. Donovan. These experiments include an introduction, staining procedures, biochemical reactions, mutagenesis experiment, essays,. preparation and analysis of plasmid DNA and various other topics. Part 2 covers the experiments conducted by Dr. Daniel Kunz and includes various topics like media preparation, phenotyping strains, conjugative transfer of plasmids, SDS-PAGE, induction and measurement of enzyme and transposon mutagenesis