This study contributes a procedure, based on data analysis and geostatistical methods, to evaluate the distribution of chemical ratios and differentiate natural and anthropogenic contaminant sources of groundwater quality in the East Texas Basin. Four aquifers were studied, Sparta, Queen City, Carrizo and Wilcox. In this study, Carrizo- Wilcox is considered as one aquifer, and Sparta-Queen City as another. These aquifers were divided into depth categories, 0-150 feet for Sparta-Queen City and 300-600 feet and 600-900 feet for Carrizo-Wilcox in order to identify individual sources of contamination. Natural sources include aquifer mineral make up, salt domes and lignite beds. Major anthropogenic sources include lignite and salt dome mining and oil-gas production. Chemical ratios selected were Na/Cl, Ca/Cl, Mg/Cl, SO4/Cl, (Na+Cl)/TDS, SO4/Ca and (Ca+Mg)/(Na+K). Ratio distributions and their relationships were examined to evaluate physical-chemical processes occurring in the study area. Potential contaminant sources were used to divide the Basin into three areas: Area 1 to the east, Area 2 in the west and Area 3 in the center. Bivariate analysis was used to uncover differences between the areas. The waters in Area 1 are potentially impacted primarily from oil field waters. Sources present in Area 2 include lignite beds and oil …

A biological monitoring tool to assess water quality using bivalve gape behavior was developed and demonstrated. The purpose of this work was to develop methodologies for screening water quality appropriate to the goals of the watershed paradigm. A model of bivalve gape behavior based on prediction of behavior using autoregressive techniques was the foundation of the bivalve biomonitoring system. Current technology was used in developing the system to provide bivalve gape state data in a continuous real-time manner. A laboratory version of the system, including data collection and analysis hardware and software, was developed for use as a toxicological assay for determination of effective concentrations of toxicant(s) or other types of stress on bivalve gape behavior. Corbicula fluminea was monitored and challenged with copper, zinc, and chlorpyrifos using the system. Effective concentrations of 176±23µg/L copper, 768±412µg/L zinc, and 68µg/L chlorpyrifos were observed using a natural water with high dissolved organic carbon concentrations. A rugged field version of the bivalve biomonitoring system was developed and deployed in two locations. The field systems were fitted with a photovoltaic array, a single board computer, and a CDPD telemetry modem for robust remote operation. Data were telemetered at a time relevant rate of once …

Pseudomonas aeruginosa is a Gram-negative rod, aerobic, non-fermenting, oxidase positive, pigment producing, and nutritionally versatile bacterium. Infections by P. aeruginosa are the most important cause of morbidity and mortality in immunocompromised patients, given virulence factor production that suppresses antibiotic therapy and promotes persistent infection. This research is the first comprehensive report of the pyrimidine biosynthetic pathway for all phases of growth in minimal and rich media coupled with the evaluation of virulence factor production of P. aeruginosa in comparison to four other bacterial species (Pseudomonas putida, Pseudomonas fluorescens, Burkholderia cepacia, and Escherichia coli wild-type strains). Cellular growth and passing genetic information to the next generation depend on the synthesis of purines and pyrimidines, the precursors of DNA and RNA. The pyrimidine biosynthetic pathway is essential and found in most organisms, with the exception of a few parasites that depend upon the pyrimidine salvage pathway for growth. Both the pyrimidine biosynthetic and salvage enzymes are targets for chemotherapeutic agents. In our laboratory, research on pyrimidine auxotrophic mutants showed the role of the pyrimidine biosynthetic pathway and its intermediates on P. aeruginosa metabolism and impaired virulence factors production. The present research shows that pyrimidine enzymes are active in all phases of growth, …

Temperature effects on the development of the zebrafish embryos and larvae and adults were examined. It was found that the earlier in development a temperature change was performed on an embryo, the more significant the change in survival and/or subsequent development. Thus, viable temperature ranges for zebrafish widened significantly as development proceeded. Adults reared and bred at 25oC produced embryos that were significantly more successful at the lower range of rearing temperatures compared to embryos produced from adults reared at 28oC. The majority of this study focused on the physiological effects of swim training during development in the zebrafish. The earlier in development the zebrafish larvae were trained, the greater the mortality. Trained free swimming larvae had a significantly higher routine oxygen consumption after 11 days of training, and a higher mass specific routine metabolic rate after 8 and 11 days of training. Trained free swimming larvae consumed significantly less oxygen during swimming and were more efficient at locomotion, compared to control larvae. Training enhanced survival during exposure to extreme hypoxia in all age groups. Performance aspects of training were investigated in attempt to quantify training effects and in most cases, trained fish performed significantly better than controls. As blood …

This study identifies the biogeographic factors that structure small mammal communities on mountains of the Colorado Plateau and adjacent regions. Forty six isolated ranges were characterized across a 5-state study area encompassing the Colorado Plateau, including the central high plateaus of Utah and the Basin and Range Province (i.e. the Great Basin and mountains of Arizona and New Mexico). Presence/absence data of 25 montane mammal species were used to explore the interactions between historical and ecological processes affecting local and regional diversity patterns. Multivariate analyses, such as non-metric dimensional scaling, were used to explore factors which influence community composition. Results of these analyses revealed the Colorado River as a significant biogeographic barrier that affects montane mammal community structure. MtDNA cytochrome b sequence variation was analyzed among populations of the long-tailed vole, Microtus longicaudus, sampled from five interior ranges of the Colorado Plateau- Abajo, LaSal, Henry, and Chuska Mts., and Boulder Mountain of the Aquarius Plateau-and analyzed using traditional phylogenetic approaches (parsimony and likelihood) as well as nested clade analysis. Results support previous documentation of a major east-west phylogeographic break occurring between populations southeast of the Colorado River (eastern Arizona, Colorado, Wyoming and New Mexico) and all other western populations, which …

TNT (2,4,6-trinitrotoluene) is a persistent contaminant at many military installations and poses a threat to aquatic ecosystems. Data from environmental fate and toxicity studies with TNT revealed that sediment toxicity test procedures required modification to accurately assess sediment TNT toxicity. Key modifications included aging TNT-spiked sediments 8-14 d, basing lethal dose on measured sediment concentrations of the molar sum of TNT and its main nitroaromatic (NA) transformation products (SNA), basing sublethal dose on average sediment SNA concentrations obtained from integration of sediment SNA transformation models, avoiding overlying water exchanges, and minimizing toxicity test durations. Solid phase microextraction fibers (SPMEs) were investigated as a biomimetic chemical measure of toxicity and bioavailability. Both organism and SPME concentrations provided measures of lethal dose independent of exposure scenario (TNT-spiked sediment or TNT-spiked water) for Tubifex tubifex. Among all benthic organisms tested (Chironomus tentans, Ceriodaphnia dubia, T. tubifex) and matrixes, median lethal dose (LC50) estimates based on SPME and organism concentrations ranged from 12.6 to 55.3 mmol SNA/ml polyacrylate and 83.4 to 172.3 nmol SNA/g tissue, ww, respectively. For Tubifex, LC50s (95% CI) based on SNA concentrations in sediment and SPMEs were 223 (209-238) nmol SNA/g, dw and 27.8 (26.0-29.8) mmol SNA/ml, respectively. Reproductive effects …

In this research, the necessity of understanding and using bioinformatics is demonstrated using the enzyme aspartate transcarbamoylase (ATCase) as the model enzyme. The first portion of this research focuses on the use of bioinformatics. A partial sequence of the pyrB gene found in Enterococcus faecalis was submitted to GenBank and was analyzed against the contiguous sequence from its own genome project. A BLAST (Basic Local Alignment Search Tool; Atschul, et al., 1990) was performed in order to hypothesize the remaining portion of the gene from the contiguous sequence. This allowed a global comparison to other known aspartate transcarbamoylases (ATCases) and once deduced, a translation of the sequence gave the stop codon and thus the complete sequence of the open reading frame. When this was complete, upstream and downstream primers were designed in order to amplify the gene from genomic DNA. The amplified product was then sequenced and used later in phylogenetic analyses concerning the evolution of ATCase. The second portion of this research involves taking multiple ATCase nucleotide sequences and performing phenetic and phylogenetic analyses of the archaea and eubacter families. From these analyses, ancestral relationships which dictate both structure and function were extrapolated from the data and discussed.

This dissertation research explored the capabilities of neuronal networks grown on substrate integrated microelectrode arrays in vitro to be applied to toxicological research and lipid signaling. Chapter 1 details the effects of chlorine on neuronal network spontaneous electrical activity and pharmacological sensitivity. This study demonstrates that neuronal networks can maintain baseline spontaneous activity, and respond normally to pharmacological manipulations in the present of three times the chlorine present in drinking water. The findings suggest that neuronal networks may be used as biological sensors to monitor the quality of water and the presence of novel toxicants that cannot be detected by conventional sensors. Chapter 2 details the neuromodulatory effects of N-acylethanolamides (NAEs) on the spontaneous electrical activity of neuronal networks. NAEs are a group of lipids that can mimic the effects of marijuana and can be derived from a variety of plant sources including soy lecithin. The most prominent NAEs in soy lecithin, palmitoylethanolamide (PEA) and linoleoylethanolamide (LEA), were tested individually and were found to significantly inhibit neuronal spiking and bursting activity. These effects were potentiated by a mixture of NAEs as found in a HPLC enriched fraction from soy lecithin. Cannabinoid receptor-1 (CB1-R) antagonists and other cannabinoid pathway modulators indicated …

Development and population are rapidly increasing in urbanizing areas of North Texas and so is the need to understand changes in storm water runoff flow and its contamination by nutrients, sediment, pesticides and other toxicants. This study contributes to this understanding and has two primary components: first, development of a graphical user interface for a geographic information system and storm water management database, and second, performing a two-scale hydrological modeling approach (the US Corp of Engineers HEC-HMS model and the US Environmental Protection Agency SWMM model). Both primary components are used together as a toolkit to support the storm water management program of the City of Carrollton, located in North Texas. By focusing limited city resources, the toolkit helps storm water managers in the process of compliance with federal regulations, especially the National Pollution Discharge Elimination System permit, and provides guidance for reporting, planning and investigation. A planning example was conducted by modeling potential changes in storm water quality due to projections of land use based on the City of Carrollton's Comprehensive Plan. An additional component of this study is the evaluation of future changes in surface water quantity and quality in the North Central Texas area, specifically in a …

Cyanide utilization in Pseudomonas fluorescens NCIMB 11764 occurs via oxidative conversion to carbon dioxide and ammonia, the latter satisfying the nitrogen requirement. Substrate attack is initiated by an enzyme referred to as cyanide oxygenase (CNO), previously shown to require components in both high (H) (>30 kDa) and low (L) (<10 kDa) molecular weight cell fractions. In this study, tetrahydrobiopterin (H4biopterin) was identified as a cofactor in fraction L, thus making CNO appear as a pterin- dependent hydroxylase. CNO was purified 150-fold (specific activity 0.9 U/mg) and quantitatively converted cyanide to formate and ammonia as reaction products. When coupled with formate dehydrogenase, the complete enzymatic system for cyanide oxidation to carbon dioxide and ammonia was reconstituted. CNO was found to be an aggregate of known enzymes that included NADH oxidase (Nox), NADH peroxidase (Npx), cyanide dihydratase (CynD) and carbonic anhydrase (CA). A complex multi-step reaction mechanism is proposed in which Nox generates hydrogen peroxide which in turn is utilized by Npx to catalyze the oxygenation of cyanide to formamide accompanied by the consumption of one and two molar equivalents of oxygen and NADH, respectively. The further hydrolysis of formamide to ammonia and formate is thought to be mediated by CynD. The …

Invasive pulmonary aspergillosis is a life-threatening fungal infection commonly observed in immunocompromised patients and has a mortality rate approaching 100% once the disease is disseminated. Aspergillus fumigatus is the most common pathogen. Early diagnosis improves the prognosis but is very difficult since most signs and symptoms are nonspecific. Antifungal therapy, usually based on sterol biosynthesis inhibitors, is also of limited efficacy. In my attempts to discover a diagnostic sterol marker for aspergillosis, I observed that A. fumigatus incorporates large amounts of cholesterol from serum-containing medium. This observation suggested the hypothesis that exogenous cholesterol from the host can be imported by A. fumigatus and used as a substitute for ergosterol in the cell membrane. This proposed mechanism would reduce the efficacy of antifungal drugs that act as sterol biosynthesis inhibitors. Experiments to test this hypothesis were designed to determine the effects of serum-free and serum-containing medium on growth of A. fumigatus in the presence and absence of azole antifungal agents. The results showed a marked increase in growth in the presence of human serum. Cultures in media containing cholesterol but no serum also showed enhanced growth, a result indicating that a non-cholesterol component of serum is not primarily responsible for the …

The forest avian community of the Ray Roberts Greenbelt (Denton Co., Texas) was characterized for two years using point count station sampling, from fall 1998 to summer 2000. Richness data for both breeding seasons were correlated with two-spatial metrics: width of the riparian forest and distance to the nearest edge. There were significant correlations between forest interior species richness and both spatial metrics, for both breeding seasons. Based on these data, a minimum riparian forest width threshold of 400-meters is suggested to provide habitat for forest interior species, which have lost considerable habitat through forest fragmentation. Partners in Flight breeding bird priority concern scores were used to create a habitat priority index for the Trinity River bottomland hardwood forest system

One of the challenges in biology is placing a function on the myriad of gene sequences having become available from rapid advances in genome sequencing. One such example is a gene cluster (Nit1C) found in bacteria that is tied to the unusual ability of certain bacteria to grow when supplied cyanide as the sole nitrogen source. The term cyanotrophs has been applied to such bacteria, for which a genetic linkage between cyanotrophy and Nit1C was demonstrated for 10 separate bacteria. In addition to growth, cyanide induced the expression of Nit1C genes in all organisms tested, and in one case, deletion of one of the Nit1C genes (nitC) caused a loss of growth. Of the ten bacteria able to grow cyanotrophically, all gave evidence of harboring Nit1C on their genome except for two (Pseudomonas fluorescens Pf11764 and P. monteilii BCN3), which were sequenced and the presence of Nit1C was also confirmed. A broader search of bacteria identified 270 separate strains with the cluster, all limited to bacteria spanning the phyla Firmicutes, Actinobacteria, Proteobacteria and Cyanobacteria. Remarkably, many examples of a single representative of a given taxon contained Nit1C, most poignantly displayed by Pf11764 and PmBCN3; the interpretation being the cluster was …

A study was conducted to evaluate the sorption characteristics of six disinfection byproducts (DBPs) on four sorbents. To investigate sorption of volatile organic compounds (VOCs), specially designed experimental batch and continuous flow modules were developed. The investigated compounds included: chloroform, 1,2-dichloroethane (DCE), trichloroethylene (TCE), bromodichloromethane (BDCM), methyl tertiary butyl ether (MTBE), bromate and bromide ions. Sorbents used included light weight aggregate (LWA), an inorganic porous material with unique surface characteristics, Amberlite® XAD-16, a weakly basic anion exchange resin, Amberjet®, a strongly basic anion exchange resin, and granular activated carbon (GAC). Batch experiments were conducted on spiked Milli-Q® and lake water matrices. Results indicate considerable sorption of TCE (68.9%), slight sorption of bromate ions (19%) and no appreciable sorption for the other test compounds on LWA. The sorption of TCE increased to 75.3% in experiments utilizing smaller LWA particle size. LWA could be a viable medium for removal of TCE from contaminated surface or groundwater sites. Amberlite® was found unsuitable for use due to its physical characteristics, and its inability to efficiently remove any of the test compounds. Amberjet® showed an excellent ability to remove the inorganic anions (>99%), and BDCM (96.9%) from aqueous solutions but with considerable elevation of pH. …

I used the C. elegans genetic model to examine the role of ceramide biosynthesis (sphingolipid pathway) and iron regulation and found that each process impacts germline development and function. Using a sphingolipid specific antibody mAb15B4, I found that sphingolipids are associated with germ granules (P granules) within C. elegans and zebrafish; thus, suggesting conservation of macromolecules associated with germ granules. Phenotype analysis of ceramide biosynthesis mutants in C. elegans revealed that this pathway is essential for normal germline function in the aging adult hermaphrodite; specifically, precocious germline senescence was observed. Furthermore, I found that disruption of ceramide biosynthesis, via the hyl-2 deletion mutation, negatively impacts mAb15B4 localization at the P granules. Through genetic suppression analysis, I determined that insulin signaling and lipid biosynthesis can modulate the mAb15B4 localization to P granules. Additional, phenotype analysis showed that ceramide biosynthesis dysfunction decreased fecundity, and led to germline structure defects and uterine tumors. Through suppression analysis, I determined that modulation of the insulin signaling pathway suppressed the precocious germline senescence due to ceramide biosynthesis dysfunction. Since the presence of uterine tumors is associated with reproductive senescence I concluded that ceramide biosynthesis has a role in germline maintenance in the aging of the germline …

The regulation of pyrimidine biosynthesis was studied in Pseudomonas putida. The biosynthetic and salvage pathways provide pyrimidine nucleotides for RNA, DNA, cell membrane and cell wall biosynthesis. Pyrimidine metabolism is intensely studied because many of its enzymes are targets for chemotheraphy. Four aspects of pyrimidine regulation are described in this dissertation. Chapter I compares the salvage pathways of Escherichia coli and P. putida. Surprisingly, P. putida lacks several salvage enzymes including nucleoside kinases, uridine phosphorylase and cytidine deaminase. Without a functional nucleoside kinase, it was impossible to feed exogenous uridine to P. putida. To obviate this problem, uridine kinase was transferred to P. putida from E. coli and shown to function in this heterologous host. Chapter II details the enzymology of Pseudomonas aspartate transcarbamoylase (ATCase), its allosteric regulation and how it is assembled. The E. coli ATCase is a dodecamer of two different polypeptides, encoded by pyrBI. Six regulatory (PyrI) and six catalytic (PyrB) polypeptides assemble from two preformed trimers (B3) and three preformed regulatory dimers (I2) in the conserved 2B3:3I2 molecular structure. The Pseudomonas ATCase also assembles from two different polypeptides encoded by pyrBC'. However, a PyrB polypeptide combines with a PyrC. polypeptide to form a PyrB:PyrC. protomer; six …

Using a high throughput closed respirometry method to measure oxygen consumption, I determined metabolic rates in asexual and sexual Schmidtea mediterranea and Girardia dorotocephala, as a function of temperature, taxon, stressors, reproductive mode, age, regeneration, and specific dynamic action. This study has shown that oxygen consumption can reliably be measured in planaria using optode closed respirometry, and also provided a reliable method for measuring wet mass in planaria, which has been a challenge to researchers in the past. This research revealed that oxygen consumption in S. mediterranea is 1.5-2.1X greater in the sexual strain over the asexual strain at 13-18°C. Within the sexual strain, oxygen consumption is 1.5 -2.2X greater in sexually mature adults over the sexually immature groups (hatchlings, juveniles, and regenerating sexuals). Furthermore, I was able to quantify differences in sexual morphology between these groups exhibiting significant differences in oxygen consumption. The results of this research supports a theory of higher metabolic costs with sexual maturity in S. mediterranea. Therefore, this study has established sexual and asexual S. mediterranea as simple, yet attractive models for investigating energetic costs between sexual and asexual phenotypes. This research also provided quantitative values for specific dynamic action in planaria, with a maximum …

In this study, two different field experiments were designed to assess the relative influence of urbanization on benthic communities. During spring and summer, four urban and one reference sites from Denton County, Texas were selected for benthic macroinvertebrate evaluation. Statistically significant differences in colonized benthic macroinvertebrate taxa on artificial substrates were observed among the four urban sites and the reference site. Oligochaetes and chironomids were the dominant taxa at all sites. Identification of chironomid larvae at the subfamily and genus level to detect differences between sites had higher statistical power than the evaluation based on total chironomids. At the reference site, Caenis, Cladotanytarsus, Orthocladius, and Ceratopogonidae were the dominant taxa, while the urban sites were dominated by Dero, Physella, Ancylidae, Chironomus, Dicrotendipes, Glyptotendipes, Polypedilum, Pseudochironomus, Stenochironomus, and Tanytarsus. These differences may have been dependent upon differences in hydrologic regime and water quality between sites. Significant differences (ANOVA, p < 0.01) in water quality parameters (alkalinity, hardness, nitrates, phosphates, chlorides, sulfates, calcium, magnesium, potassium, and triazine) were found among water samples collected from the reference and urban sites. During the transfer period, most of the Ephemeroptera and Trichoptera taxa and a few other taxa disappeared from artificial substrates that were colonized …

Networks of ground-based and satellite borne instruments to measure ultraviolet (UV) sunlight and total column ozone have greatly contributed to an understanding of increased amounts of UV reaching the surface of the Earth caused by stratospheric ozone depletion. Increased UV radiation has important potential effects on human health, and agricultural and ecological systems. Observations from these networks make it possible to monitor total ozone decreases and to predict ozone recovery trends due to global efforts to curb the use of products releasing chemicals harmful to the ozone layer. Thus, continued and expanded global monitoring of ozone and UV is needed. However, existing automatic stratospheric ozone monitors are complex and expensive instruments. The main objective of this research was the development of a low-cost fully automated total column ozone monitoring instrument which, because of its affordability, will increase the number of instruments available for ground-based observations. The new instrument is based on a high-resolution fiber optic spectrometer, coupled with fiber optics that are precisely aimed by a pan and tilt positioning mechanism and with controlling programs written in commonly available software platforms which run on a personal computer. This project makes use of novel low-cost fiber optic spectrometer technology. A cost …

Throughout history floods have been part of the human experience. They are recurring phenomena that form a necessary and enduring feature of all river basin and lowland coastal systems. In an average year, they benefit millions of people who depend on them. In the more developed countries, major floods can be the largest cause of economic losses from natural disasters, and are also a major cause of disaster-related deaths in the less developed countries. Flood disaster mitigation research was conducted to determine how remotely sensed data can effectively be used to produce accurate flood plain maps (FPMs), and to identify/quantify the sources of error associated with such data. Differences were analyzed between flood maps produced by an automated remote sensing analysis tailored to the available satellite remote sensing datasets (rFPM), the 100-year flooded areas "predicted" by the Flood Insurance Rate Maps, and FPMs based on DEM and hydrological data (aFPM). Landuse/landcover was also examined to determine its influence on rFPM errors. These errors were identified and the results were integrated in a GIS to minimize landuse / landcover effects. Two substantial flood events were analyzed. These events were selected because of their similar characteristics (i.e., the existence of FIRM or …

Cowpea, Vigna unguiculata (L.) Walp is an excellent source of protein, vitamins and minerals and a major food crop many parts of Africa. Optimal production levels are hampered by insect pests and diseases. Biotechnological techniques such as tissue culture and genetic engineering can aid in the development of varieties with resistance to insect pests and diseases. The objective of this study was to investigate conditions necessary for the development of a reproducible tissue culture system that can be applied to regenerate transformed cells from culture. The in vitro manipulation of cowpea using Murashige and Skoog (MS) medium, auxins and cytokinins resulted in the formation of callus and rhizogenesis. Calli that were formed were separated into six classes based on color and texture. Yellowish friable callus, yellowish compact, soft yellowish callus and green and white were composed of largely vacuolated cells and were non-regenerative. Friable green callus was the most prevalent callus type and could form of roots in some hormone combinations. Green spots were formed on hard compact green callus. The green spots became nodular, forming root primordia and ultimately giving rise to roots. None of the six calli types gave rise to the formation of shoots. Embryogenic callus was …

Estrogen is the natural agonist of the estrogen receptor (ER). However, certain plant-derived compounds or phytoestrogens have been identified that mimic estrogens and act as agonists and/or antagonists of ERs, depending on subtype and target tissue. Understanding how phytoestrogens interact with ERs, and therefore effect the estrogenic response, may prove beneficial in hormone replacement therapy and in the prevention and treatment of hormone-related diseases. Using Thin Layer Chromatography, gas chromatography/mass spectrometry (GC/MS), and proton nuclear nagnetic resonance (HNMR), I identified 4-ethoxymethylphenol (4EM) found in Maclura pomifera. While most phytoestrogens are heterocyclic compounds, 4EM is a simple phenol that acts as an agonist of ER-alpha and -beta in HeLa and MCF-7 cells. To study the effect of 4EM on ER-alpha and -beta activity, I performed transient transfection assays and showed that 4EM activates ER dependent gene transcription in a dose dependent manner in both ER subtypes. Further, 4EM- mediated transcription in ER-alpha, like estrogen, was enhance in the presense of co-activators, SRC-1 (steroid receptor coactivator-1), CBP (CREB binding proteins), and E6-AP (E6-associated protein) and inhibited by trans-4- hydroxytamoxifen (4HT). I found that 4EM was specific for ER and did not activate transcription of the progesterone receptor in HeLa cells.

Sensilla styloconica on the proboscis of 107 species of North American and tropical butterflies were comparatively studied using the scanning electron microscope. Focus was on 76 species of North American Nymphalidae representing 45 genera and 11 subfamilies. Nomenclature for generalized and specific types of nymphalid sensilla is proposed. Written descriptions and micrographs are presented for each species studied. Morphological features were generally consistent for all or most species within genera and sometimes within subfamilies, with specified exceptions. Statistical analysis revealed significant differences for six of eight variables tested between two distinct feeding guilds of North American Nymphalidae. Average number, density, extent of proboscis coverage with sensilla, their total length, and shoulder spine length were all significantly greater in the non-nectar feeding guild than in nectar feeders, and may indicate adaptation for greater efficiency in feeding on flat surfaces. The greater frequency of apical shoulder spines in non-nectar feeders may represent adaptation for protection of sensory pegs from mechanical abrasion during feeding, or for anchoring the flexible proboscis tip to the surface. Correlation analysis revealed 9 out of 28 positive correlations in nectar feeders and 5 out of 28 in non-nectar feeders. Results of preliminary cladistic analysis were not considered to …

Cloning and molecular characterization of new genes constitutes a useful approach in studying the symbiotic interactions between the model plant Medicago truncatula and Synorhizobium meliloti. Large numbers of expressed sequence tags (ESTs) available for Medicago truncatula, along with numerous cDNA, oligonucleotides, and Affimetrix DNA microarray chips, represent useful tools for gene discovery. In an attempt to identify a new gene that might be involved in the process of nodulation in Medicago truncatula, preliminary data reported by Fedorova et al. (2002), who identified 340 putative gene products or tentative consensus sequences (TCs) expressed only in nodules, was used. This research was focused on TC33166 (TC103185), which has 3 ESTs in the TC, and whose strongest BLASTX hit of TC103185 is the incomplete root hair elongation (IRE) protein kinase-like protein (NP_192429) from Arabidopsis thaliana. The Arabidopsis IRE gene is required for normal root hair growth, and a role in apical growth was suggested (Oyama et al., 2002). Infection thread growth can be looked at as an inward growth of the root hair. Thus, TC103185 was a good candidate for identifying a gene that may be involved in early events of nodulation. MtIRE (GenBank accession AC122727) is organized in 17 exons and 16 …