Degree Level

Analysis of the Trypanosoma brucei Genome and Identification and Characterization of a Gene Family Encoding Putative EF-Hand Calcium-Binding Proteins (open access)

Analysis of the Trypanosoma brucei Genome and Identification and Characterization of a Gene Family Encoding Putative EF-Hand Calcium-Binding Proteins

The flagellum of Trypanosoma brucei contains a family of antigenically related EF-hand calcium-binding proteins which are called the calflagins. Genomic Southern blots indicated that multiple copies of calflagin genes occur in T brucei. All of the copies were contained in a single 23 kb Xhol-Xhol fragment. Genomic fragments of 2.5 and 1.7 kb were cloned that encoded calflagin sequences. Two new members of the calflagin family were found from genomic clone sequences. The deduced amino acid sequences of the genomic clones showed the calflagin genes were arranged tandemly along the genomic fragments and were similar to previously described calflagins. The calflagin genes were related by two unrelated 3' flanking sequences. An open reading frame that was unrelated to any calflagin was found at the 5' end of the 2.5 kb genomic fragment. Each encoded protein (~24,000u) contained three EF-hand calcium-binding motifs and one degenerate EF-hand motif. In general, variability among the T. brucei calflagins is greater than related proteins in T. lewisii and T. cruzi. This variability results from amino acid substitutions at the amino and carboxy termini, and duplication of internal segments.
Date: May 1998
Creator: DeFord, James H. (James Henry), 1956-
System: The UNT Digital Library
Biochemical Identification of Molecular Components Required for Cyanide Assimilation in Pseudomonas fluorescens NCIMB 11764 (open access)

Biochemical Identification of Molecular Components Required for Cyanide Assimilation in Pseudomonas fluorescens NCIMB 11764

Utilization of cyanide as a nutritional nitrogen source in P. fluorescens NCIMB 11764 was shown to involve a novel metabolic mechanism involving nonenzymatic neutralization outside of cells prior to further enzymatic oxidation within. Several cyanide degrading enzymes were produced by NCIMB 11764 in response to growth or exposure to cyanide, but only one of these cyanide, oxygenase (CNO), was shown to be physiologically required for assimilation of cyanide as a growth substrate.
Date: May 1998
Creator: Chen, Jui-Lin
System: The UNT Digital Library
Biogeographic Relationships of Pocket Gophers (Geomys breviceps and Geomys bursarius) in the Southeastern Portion of Their Ranges (open access)

Biogeographic Relationships of Pocket Gophers (Geomys breviceps and Geomys bursarius) in the Southeastern Portion of Their Ranges

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 …
Date: August 1998
Creator: Elrod, Douglas Allen
System: The UNT Digital Library
Cottonseed Microsomal N-Acylphosphatidylethanolamine Synthase: Identification, Purification and Biochemical Characterization of a Unique Acyltransferase (open access)

Cottonseed Microsomal N-Acylphosphatidylethanolamine Synthase: Identification, Purification and Biochemical Characterization of a Unique Acyltransferase

N-Acylphosphatidylethanoiamine (NAPE) is synthesized in the microsomes of cotton seedlings by a mechanism that is possibly unique to plants, the ATP-, Ca2+-, and CoA-independent acylation ofphosphatidylethanolamine (PE) with unesterified free fatty acids (FFAs), catalyzed by NAPE synthase. A photoreactive free fatty acid analogue, 12-[(4- azidosalicyl)amino]dodecanoic acid (ASD), and its 125I-labeled derivative acted as substrates for the NAPE synthase enzyme.
Date: December 1998
Creator: McAndrew, Rosemary S. (Rosemary Smith)
System: The UNT Digital Library
Dalbergia and Albizia: Plantlet Production via Tissue Culture, Karyological Evaluation, and Seed Anatomy with Scanning Electron Microscopy (open access)

Dalbergia and Albizia: Plantlet Production via Tissue Culture, Karyological Evaluation, and Seed Anatomy with Scanning Electron Microscopy

A publication by the National Academy of Sciences, USA (1979) outlined some of the research need for a great variety of economically important woody species whose remaining genetic resources need urgently to be collected and conserved. A viable regeneration system was established via tissue and cell suspension culture for Albizia falcataria and A. lebbeck, two important wood yielding leguminous tree species. The culture medium was standardized after several trials to obtain callus from the leaflet explants of these two tree species. The optimum use of casein hydrolysate (w/v) and coconut milk (v/v) in addition to 6-Benzylaminopurine and Indole-3-butyric acid could induce morphogenesis and somatic embryogenesis in the cultured tissue. This reports the first observation on somatic embryogenesis ofA. lebbeck using leaflets as the explants. Scanning Electron Microscopy and histological studies were done on the different stages plant development following standard techniques. Embryogenesis in suspension culture followed regeneration of plantlets in A. lebbeck. In A.falcaaria the regenerative process followed via organogenesis from the shoot buds developed on the leaf explants. After hardening the regenerated plants were transferred to the greenhouse. Some of the trees grew more than 25 feet tall within a few months outside the greenhouse. Karyotype of the three …
Date: December 1998
Creator: Ghosh, Nabarun
System: The UNT Digital Library
Effects of 5-hydroxytryptamine on Mouse Lumbar Motor Activity During Postnatal Development (open access)

Effects of 5-hydroxytryptamine on Mouse Lumbar Motor Activity During Postnatal Development

The lumbar motor activity in isolated spinal cords of 72 postnatal Balb/C mice aged 2, 5, 10 and 21 days (PN2-21) was electroneurographically recorded (ENG) via bilateral ventral roots following treatment with three different concentrations (25, 100 and 200 pM) of the neurotransmitter, 5-hydroxytryptamine (5-HT), i.e., serotonin, to determine its effects on spinal pattern generation.
Date: December 1998
Creator: Lowe-Chatham, Janice E. (Janice Elaine)
System: The UNT Digital Library
Physical and Functional Characterization of the xy1XYZ Region From TOL Plasmid pDK1 and its Associated Downstream Regulatory Elements (open access)

Physical and Functional Characterization of the xy1XYZ Region From TOL Plasmid pDK1 and its Associated Downstream Regulatory Elements

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.
Date: August 1998
Creator: Hares, Douglas R. (Douglas Ryan)
System: The UNT Digital Library
Pyrimidine Biosynthesis in the Genus Streptomyces : Characterization of Aspartate Transcarbamoylase and Its Interaction with Other Pyrimidine Enzymes (open access)

Pyrimidine Biosynthesis in the Genus Streptomyces : Characterization of Aspartate Transcarbamoylase and Its Interaction with Other Pyrimidine Enzymes

Aspartate transcarbamoylase (ATCase) of Streptomyces was characterized and its interaction with other pyrimidine enzymes explored.
Date: May 1998
Creator: Hughes, Lee E. (Lee Everette)
System: The UNT Digital Library
Search for Surrogate Marker(s) of Immunity Following Vaccination with Experimental Vaccine (Autoclaved Leishmania Major + Bacille Calmette-Guérin) in Human Volunteers (open access)

Search for Surrogate Marker(s) of Immunity Following Vaccination with Experimental Vaccine (Autoclaved Leishmania Major + Bacille Calmette-Guérin) in Human Volunteers

Cutaneous leishmaniasis (CL) is usually a self-limiting lesion on the skin while visceral leishmaniasis is a progressive, systemic disease with high mortality even if treated. The problem associated with treatment and vector control justifies a search for an effective vaccine which seems to be the only practical means to control the disease. The aim of this study is to identify immunological surrogate marker(s) associated with protection against Leishmania infection. The results indicate that a single dose of ALM+BCG induced Thl-like response but the level of such response is not sufficient for full protection. Accordingly, further evaluation of the vaccine is necessary other strategies multiple injections or changing the adjutant.
Date: December 1998
Creator: Mahmoodi, Majid
System: The UNT Digital Library