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  Partner: UNT Libraries
 Department: Department of Biological Sciences
 Degree Level: Master's
 Collection: UNT Theses and Dissertations
Life History And Secondary Production Of Cheumatopsyche Lasia Ross (Trichoptera: Hydropsychidae) With Respect To A Wastewater Treatment Facility In A North Texas Urban Stream

Life History And Secondary Production Of Cheumatopsyche Lasia Ross (Trichoptera: Hydropsychidae) With Respect To A Wastewater Treatment Facility In A North Texas Urban Stream

Date: December 2011
Creator: Paul, Jenny Sueanna
Description: This study represents the first shift in multivoltine life history of Cheumatopsyche species from a wastewater treatment plant (WWTP) in North America. Populations of C. lasia were examined upstream and downstream of the Denton’s Pecan Creek WWTP August 2009 through November 2010. C. lasia is multivoltine in Pecan Creek with three cohorts observed upstream of the WWTP and four possible cohorts downstream. A fourth generation was possible downstream as thermal inputs from WWTP effluent resulted in elevated water temperatures that allowed larval development to progress through the winter producing a cohort ready to emerge in spring. Production of C. lasia was 5 times greater downstream of the WWTP with secondary production estimates of 1.3 g m-2 yr-1 and 4.88- 6.51 g m-2 yr-1, respectively. Differences in abundance were due to increased habitat availability downstream of the WWTP in addition to continuous stream flow from inputs of wastewater effluent. Results also suggest that C. lasia is important for energy transfer in semiarid urban prairie streams and may serve as a potential conduit for the transfer of energy along with emergent contaminants to terrestrial ecosystems. These finding highlight the need for more quantitative accounts of population dynamics (voltinism, development rates, secondary production, ...
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Life History of Mayatrichia ponta Ross (Trichoptera: Hydroptilidae) in Honey Creek, Turner Falls Park, Oklahoma

Life History of Mayatrichia ponta Ross (Trichoptera: Hydroptilidae) in Honey Creek, Turner Falls Park, Oklahoma

Date: December 1997
Creator: Wang, Yi-Kuang
Description: The life history and ontogenetic microhabitat change of Mayatrichia ponta Ross were investigated in Honey Creek, Turner Falls Park, Murray Co., Oklahoma, U.S.A. from August 1994 to August 1995. The shape of larval cases changed from a small cone to a cylinder. M. ponta had an asynchronous multivoltine life history with considerable cohort and generation overlap; five generations were estimated. The development rate was reduced in winter. The winter generations of M. ponta had wider head capsule widths (136-165 μm) than summer generations (121-145 μm). The sex ratio of adults was 1.43 ♂ : 1 ♀. Fecundity ranged from 46 to 150 eggs/female. Fifth instar larvae and pupae aggregated on the bottom side of substrates. Early instars were distributed evenly on all sides of substrates. General patterns of ontogenetic microhabitat shift in aquatic insects are categorized as flow mediated, flow independent, and population interactions and other resources mediated.
Contributing Partner: UNT Libraries
Linkage of a nitrilase-containing Nit1C gene cluster to cyanide utilization in Pseudomonas fluorescens NCIMB 11764.

Linkage of a nitrilase-containing Nit1C gene cluster to cyanide utilization in Pseudomonas fluorescens NCIMB 11764.

Access: Use of this item is restricted to the UNT Community.
Date: May 2009
Creator: Ghosh, Pallab
Description: Pseudomonas fluorescens NCIMB 11764 (Pf11764) is uniquely able to grow on the poison cyanide as its sole nitrogen source. It does so by converting cyanide oxidatively to carbon dioxide and ammonia, the latter being assimilated into cellular molecules. This requires a complex enzymatic machinery that includes nitrilase and oxygenase enzymes the nature of which are not well understood. In the course of a proteomics analysis aimed at achieving a better understanding of the proteins that may be required for cyanide degradation by Pf11764, an unknown protein of 17.8 kDa was detected in cells exposed to cyanide. Analysis of this protein by ESI-coupled mass spectrometry and bioinformatics searches gave evidence of strong homology with a protein (Hyp1) of unknown function (hypothetical) present in the bacterium Photorhabdus luminescens subsp. laumondii TTO1 (locus plu_1232). A search of available microbial genomes revealed a number of Hyp1 orthologs the genes of which are found in a conserved gene cluster known as Nit1C. Independent studies revealed that in addition to Hyp1, Pf11764 possesses a gene (nit) specifying a nitrilase enzyme whose closest homologue is a nitrilase found in Nit1C gene clusters (77% amino acid identity). DNA sequence analysis has further revealed that indeed, hyp1Pf11764 and nitPf11764 ...
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Macroinvertebrate Community Structure as an Indicator of Watershed Health in the Upper Trinity River Basin, North Central Texas

Macroinvertebrate Community Structure as an Indicator of Watershed Health in the Upper Trinity River Basin, North Central Texas

Access: Use of this item is restricted to the UNT Community.
Date: May 2000
Creator: Stephenson, Jaynie M.
Description: This study describes macroinvertebrate community structure and assesses its potential in detecting point and non-point sources of disturbance associated with rural and urban areas in the Upper Trinity River Basin. Geospatial techniques were used to quantify landuse within the watershed in a GIS. At rural sites near the headwaters of the Trinity River, collector-gathering burrowers that are adapted to minimal flow comprised the majority of taxa. Destinies of taxa compositions at downstream sites increased and shifted toward psammophilic and rheophilic invertebrates, including primarily collector-filtering clingers, that are characteristic of shifting sand habitats in large prairie rivers. Benthic community structure generally benefited from point source impacts including wastewater treatment plant effluents that maintained higher flow. Community indices were negatively associated with forest landuse and positively associated with urban landuse. Partial CCA determined that flow and landuse contributed equally to species dispersions. Comparisons with historical biomonitoring studies in upper Trinity River Basin indicate improved watershed health.
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Management Tools for Prescribed Burning for Tallgrass Prairie Restoration at the Lewisville Lake Environmental Learning Area

Management Tools for Prescribed Burning for Tallgrass Prairie Restoration at the Lewisville Lake Environmental Learning Area

Date: December 2003
Creator: Moreno, Maria C.
Description: The Lewisville Lake Environmental Learning Area (LLELA) is a wildlife management area with tallgrass prairie, an endangered ecosystem. Essential ecosystem processes, especially fire, are part of restoration. To support fire management efforts at LLELA and surrounding areas, this project evaluated and developed tools for fire restoration. The four primary prairie grasses respond favorably to burning. Fuel loads and fuel models vary by scale and survey method. One- and 10-hour fuel moisture can be predicted using a statistical model; 100- and 1,000-hour fuel moisture cannot. Historic weather data suggests that burning can occur when it is most effective. The production of ozone precursors produced by burning is comparable to those emitted every six minutes by regional automobiles.
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Map-based cloning of the NIP gene in model legume Medicago truncatula.

Map-based cloning of the NIP gene in model legume Medicago truncatula.

Date: May 2007
Creator: Morris, Viktoriya
Description: Large amounts of industrial fertilizers are used to maximize crop yields. Unfortunately, they are not completely consumed by plants; consequently, this leads to soil pollution and negative effects on aquatic systems. An alternative to industrial fertilizers can be found in legume plants that provide a nitrogen source that is not harmful for the environment. Legume plants, through their symbiosis with soil bacteria called rhizobia, are able to reduce atmospheric nitrogen into ammonia, a biological nitrogen source. Establishment of the symbiosis requires communication on the molecular level between the two symbionts, which leads to changes on the cellular level and ultimately results in nitrogen-fixing nodule development. Inside the nodules hypoxic environment, the bacterial enzyme nitrogenase reduces atmospheric nitrogen to ammonia. Medicago truncatula is the model legume plant that is used to study symbiosis with mycorrhiza and with the bacteria Sinorhizobium meliloti. The focus of this work is the M. truncatula nodulation mutant nip (numerous infections and polyphenolics). The NIP gene plays a role in the formation and differentiation of nodules, and development of lateral roots. Studying this mutant will contribute knowledge to understanding the plant response to infection and how the invasion by rhizobia is regulated. Previous genetic mapping placed NIP ...
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Medial Medulla Networks in Culture: a Multichannel Electrophysiologic and Pharmacological Study

Medial Medulla Networks in Culture: a Multichannel Electrophysiologic and Pharmacological Study

Date: August 1998
Creator: Keefer, Edward W. (Edward Wesley)
Description: 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.
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Metabolic Engineering in Plants to Control Source/sink Relationship and Biomass Distribution

Metabolic Engineering in Plants to Control Source/sink Relationship and Biomass Distribution

Date: August 2013
Creator: Lahiri, Ipsita
Description: Traditional methods like pruning and breeding have historically been used in crop production to divert photoassimilates to harvested organs, but molecular biotechnology is now poised to significantly increase yield by manipulating resource partitioning. It was hypothesized that metabolic engineering in targeted sink tissues can favor resource partitioning to increase harvest. Raffinose Family Oligosaccharides (RFOs) are naturally occurring oligosaccharides that are widespread in plants and are responsible for carbon transport, storage and protection against cold and drought stress. Transgenic plants (GRS47, GRS63) were engineered to generate and transport more RFOs through the phloem than the wild type plants. The transgenic lines produced more RFOs and the RFOs were also detected in their phloem exudates. But the 14CO2 labeling and subsequent thin layer chromatography analysis showed that the RFOs were most likely sequestered in an inactive pool and accumulate over time. Crossing GRS47 and GRS63 lines with MIPS1 plants (that produces more myo-inositol, a substrate in the RFO biosynthetic pathway) did not significantly increase the RFOs in the crossed lines. For future manipulation of RFO degradation in sink organs, the roles of the endogenous α-galactosidases were analyzed. The alkaline α-galactosidases (AtSIP1 and AtSIP2 in Arabidopsis) are most likely responsible for digesting RFOs ...
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Metabolic Engineering of Raffinose-Family Oligosaccharides in the Phloem Reveals Alterations in Patterns of Carbon Partitioning and Enhances Resistance to Green Peach Aphid

Metabolic Engineering of Raffinose-Family Oligosaccharides in the Phloem Reveals Alterations in Patterns of Carbon Partitioning and Enhances Resistance to Green Peach Aphid

Date: August 2010
Creator: Cao, Te
Description: Phloem transport is along hydrostatic pressure gradients generated by differences in solute concentration between source and sink tissues. Numerous species accumulate raffinose-family oligosaccharides (RFOs) in the phloem of mature leaves to accentuate the pressure gradient between source and sinks. In this study, metabolic engineering was used to generate RFOs at the inception of the translocation stream of Arabidopsis thaliana, which transports predominantly sucrose. To do this, three genes, GALACTINOL SYNTHASE, RAFFINOSE SYNTHASE and STACHYOSE SYNTHASE, were expressed from promoters specific to the companion cells of minor veins. Two transgenic lines homozygous for all three genes (GRS63 and GRS47) were selected for further analysis. Sugars were extracted and quantified by high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD), and 21-day old plants of both lines had levels of galactinol, raffinose, and stachyose approaching 50% of total soluble sugar. All three exotic sugars were also identified in phloem exudates from excised leaves of transgenic plants whereas levels were negligible in exudates from wild type leaves. Differences in starch accumulation or degradation between wild type and GRS63 and GRS47 lines were not observed. Similarly, there were no differences in vegetative growth between wild type and engineered plants, but engineered plants flowered ...
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Mixed Culture of Chlorella Pyrenoidosa TX71105 and a Variant Strain of Bacillus Megaterium

Mixed Culture of Chlorella Pyrenoidosa TX71105 and a Variant Strain of Bacillus Megaterium

Date: August 1970
Creator: Yao, Raymond Che-Fong
Description: Very little work has been done on bacteria capable of significantly inhibiting algal growth. This thesis reports the research on mixed cultures of a high-temperature strain of algae, Chlorella pyrenoidosa TX71105, and an organism isolated from the air and tentatively identified as a variant strain of Bacillus megaterium.
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