Department: Biological Sciences ![[clear]](close-x.png "Remove this limiter")
159 matches in the database.
These are records: 1 - 30.
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1.
Abu Almakarem, Amal S.
Base Triples in RNA 3D Structures: Identifying, Clustering and Classifying.
Degree: PhD, Biological Sciences, 2011, Bowling Green State University
► Base triples are recurrent sets of three interacting RNA nucleotides that hydrogen…
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▼ Base triples are recurrent sets of three interacting RNA nucleotides that hydrogen bond to each other along their base edges. Base triples occur frequently in structured RNAs, usually as parts of recurrent structural motifs or of tertiary interactions between parts of the RNA that are distant in the secondary structure. In almost all base triples, the central base interacts with each of the other bases of the triple to form two base pairs. As described in previous work by Leontis and Westhof, RNA nucleotides pair along their Watson-Crick (W), Hoogsteen (H), or Sugar (S) base edges and the resulting base pairs can be classified by identifying the interacting edges and the mutual orientations of the glycosidic bonds of the interacting nucleotides. The main goal of the present work is to test the hypothesis that the geometric base pair classification of Leontis and Westhof can be extended in a natural way to classify base triples geometrically. To test this hypothesis, the research leveraged the large number of RNA molecules that have been solved to atomic resolution by x-ray crystallography and deposited in the Protein Data Bank (PDB). Using a non-redundant (NR) data set of atomic-resolution, RNA-containing x-ray structures, a comprehensive survey of base triples was carried out in parallel with a combinatoric enumeration of base triple families predicted on the basis of the 12 geometric base triple families defined by the Leontis-Westhof nomenclature. This work predicts 108 potential geometric base triple families. Comprehensive searching of atomic-resolution RNA 3D structures found instances of 68 of the 108 predicted base triple families. Model building was carried out to determine which of the remaining 40 families are sterically feasible. Significantly, the proposed classification of base triples accounts for all but a handful of base triples observed in the structure database. The exceptions are intermediate cases in which two bases form a Watson-Crick pair and the third base interacts with both bases along their Hoogsteen or Sugar edges, without making a bona fide base pair with either base. An on-line resource was developed based on this classification of base triples that provides exemplars of all the base triples observed in the structure database and models for unobserved, predicted triples, grouped by base triple family, as well as by three-base combinations (see http://rna.bgsu.edu/Triples). This classification helps to identify recurrent triple motifs which can substitute for each other while preserving RNA 3D structure. It can also assist in producing RNA sequence phylogenies. Moreover, the classification is useful for improving methods for aligning evolutionarily related RNA sequences and modeling RNA 3D structures based on sequence alignments, including applications of RNA 3D structure prediction, such as predicting neutral and lethal mutations in structured RNA molecules.
Advisors/Committee Members: Leontis, Neocles.
Subjects: Biochemistry; Bioinformatics; Biology; Chemistry; Molecular Biology
Keywords: RNA base triple; Geometric base triple family; non-Watson-Crick base pair; RNA 3D motif; RNA triple superfamily
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2.
Al-Rshaidat, Mamoon M. D.
Iron physiological autecology of the vertically migrating diatoms Ethmodiscus spp. and Rhizosolenia spp. in the Central North Pacific (CNP) gyre.
Degree: PhD, Biological Sciences, 2006, Bowling Green State University
► Low Fe availability constrains algal primary production in numerous oceanic provinces. Although…
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▼ Low Fe availability constrains algal primary production in numerous oceanic provinces. Although not numerically abundant, the diatom microplankton (> 20 micro m) are important contributors to new production in these regions. To better understand the contributions made to new production by diatoms in Fe-depleted waters, this dissertation work addressed the Fe-specific physiological and biochemical autecology of this group. A field component consisted of two research cruises in 2002 and 2003 along a transect at 29 degrees North spanning the eastern half of the Central North Pacific (CNP) gyre, and focused on the vertically migrating bouyant giant diatom genera Rhizosolenia spp. and Ethmodiscus spp. The lab component examined physiological, biochemical and growth responses of large open-ocean and coastal diatom isolates to perturbations of Fe in the growth medium. Whereas mats of Rhizosolenias howed elevated values (ca. 0.61, n = 88) of Fv/Fm, a measure of photochemical energy conversion efficiency, along the easterly transect from Hawaii to San Diego, a clear decline in this parameter measured at locations west of 165 degrees West provided physiological evidence of nutrient limitation. By contrast, cells of Ethmodiscus showed consistently near maximal values of Fv/Fm (ca.0.7, n = 70). The higher Fv/Fmassociated with Ethmodiscus was supported in part by an enhanced Ferredoxin Index (Fd Index), a common biochemical measure for Fe status. By comparison, the Fd Index for Rhizosolenia along the western reaches of the transect was consistently depressed. Cellular Fe quotas of both diatoms rinsed with oxalate, a reagent used to reduce cell surface adsorbed Fe facilitating its removal from the cell surface, demonstrated comparable low Fe:C stoichiometry (means of 5.41 SE 4.76 and 9.21 SE 5.10) (micro mol:mol) for Ethmodiscus and Rhizosolenia, respectively. This was consistent with the presumed low dissolved Fe content of these ultraoligotrophic waters. These cellular Fe quotas represent among the first such measurements for oceanic diatoms. A Fd protein-coding gene (petF) was partially sequenced from Rhizosolenia fallax, an isolate from the CNP gyre. Application of bioinformatics tools validated the cross reactivity of Fd protein with the antibodies used for immunoblotting in this study. This petF gene sequence represents among the first petF gene sequences for open ocean diatom isolates.
Advisors/Committee Members: McKay, Michael L.
Keywords: iron; iron quota; diatom; large diatom; Rhizosolenia fallax; Ethmodiscus; trace metal; clean technique; oceanography; biogeochemistry; central north pacific; open ocean; coastal; phosphorous; scavenging; intracellular iron; Fd Index; ferredoxin
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3.
Amarachintha, Surya P.
Optimal Growth Conditions for Tracheal Epithelial Stem Cells.
Degree: MS, Biological Sciences, 2007, Bowling Green State University
► The use of stem cells and their progenitors is a promising strategy…
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▼ The use of stem cells and their progenitors is a promising strategy in cellular and genetic therapies for multiple degenerative disorders, as well as adjuvant immunotherapy for diverse aggressive cancer types (Mimeault and Batra, 2006). There are many obstacles standing in the way of the clinical use of stem cells, however, among them the establishment of optimal conditions for stem cell culture (Mannello and Tonti, 2007). This study is focused on optimizing the conditions to obtain rat tracheal epithelial stem cells. As is the case for most tissues, the stem cells were in low representation in the in vivo population. The study started with optimal preliminary growth medium (OPGM), which is the minimum essential medium required for the epithelial stem cells to grow from rat tracheal tissue. My experiments were directed at adding metallic/trace elements, lipid-soluble vitamins, and lipid nutrients to OPGM, to determine whether additional increments in growth rate would be achieved. The amount of growth per week was measured from tracings on the culture dishes over a three-week period. In those cultures maintained in high vitamin and low metal supplements to OPGM, a higher growth rate was attained than in all other combinations of supplements. This can be attributed to the importance of vitamins A, D, E, and K to the cells and to the toxicity of metallic/trace elements when present in high concentrations. Also in regard to the importance of lipoidal nutrients, I found that the level of essential fatty acids (EFA) could be increased over the levels present in OPGM, with favorable consequences for cell growth and differentiation. Therefore, it was determined that fat-soluble vitamins, metallic/trace elements, and EFA were capable of enhancing tracheal epithelial stem cell reproductive capacity.
Advisors/Committee Members: Heckman, Carol A.
Keywords: metallic/trace; PKC; vitamins; OPGM; EPITHELIAL; lipid mixtures
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4.
Amarachintha, Surya Prakash.
Cellular Architecture and Cytoskeletal Structures Involved in Cell Haptotaxis.
Degree: PhD, Biological Sciences, 2012, Bowling Green State University
► Filopodia play a sensory role in directing motility during embryonic development and…
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▼ Filopodia play a sensory role in directing motility during embryonic development and axon pathfinding. They also show a low prevalence in cancer cells. Here, I determined whether cultured cells from a rat tracheal epithelial line used filopodia to sense adhesive gradients. Cells exhibited haptotaxis (movement toward the more adhesive surface) when plated on tantalum (Ta) and platinum (Pt) metallic gradients. The gradients were created on glass, and high (H), middle (M), and low (L) positions defined along the gradient. Cell counts in randomly selected fields confirmed that the cells recognized the gradient. To determine whether the prevalence of protrusions differed at the H, M, and L locations, the values of latent factors 4 (filopodia), 5, and 7 were determined. Factor 4 values were high at H and significantly lower at M and L (p<0.05). Cells' ability to form larger protrusions, represented by factors 5 (lamellar distribution) and 7 (nascent neurites), was unaltered across the Ta gradient. The directional cues also appeared to be interpreted within a cell, as shown by analyzing the cells' top (T) side, i.e. the side oriented toward H location, from the bottom (B) side. Factor 4 values at H-T significantly exceed those at M-B and L-T. Trend analysis confirmed a decrease in factor 4 over the gradient with significance of P<0.001 (Ta) and P<0.023 (Pt). On Pt only, factor 5 increased (P<0.0001) as the metal content of the substrate declined. Cdc42 (cell division cycle 42) plays a crucial role in establishing polarity, and is also involved in filopodia formation, cell motility, and directional migration. Since there is some loss of polarity in preneoplastic lesions, the role of Cdc42 in filopodia-mediated sensing was of interest. To determine whether Cdc42 was implicated in reconstruction of cellular architecture and rearrangement of cytoskeletal structures, I tested the role of Cdc42 effectors in gradient sensing. While most effectors bind to Cdc42 at multiple regions, there is usually a short linear stretch of residues that is critical for binding. Peptides representing such stretches of Cdc42 were designed to model its surface and thereby inhibit effector-Cdc42 binding. Using filopodia trend analysis to determine the effect of each peptide, I found that ACK, IQGAP, and Par6 were essential for directional pointing of filopodia. A sequence blocking PKCε interaction with its docking site also prevented pointing activity. Although WASP binds directly to Cdc42, the peptide designed to block this interaction did not affect directional pointing of the filopodia. Introduction of the peptide against PAK gave a paradoxical result. Directional identification mechanisms were intact but the direction of filopodia pointing was reversed. I also studied the relationship between filopodia and ruffles on any given cell, in order to understand the complex processes of cell motility and directional persistence. Ruffle frequency and filopodia were inversely related, and this relationship was independent of the location on the gradient or the peptide introduced into the cells. On tantalum, sites at HT, MT, and LT and on platinum sites at HT, MT, and both LT and LB showed ruffling interacting with filopodia, with a level of significance P<0.025. Despite the tendency for ruffling activity to increase toward the less adhesive end of the gradient, none of the ruffling variables showed a statistically significant trend. However, the data suggest that cells make ruffles at the expense of filopodia regardless of substrate to which they are attached. This inverse relationship was stronger at the top of the cell than at the bottom. Thus it can be confirmed that ruffles and filopodia are inversely related, but ruffling is unlikely to be a mechanism of gradient sensing.
Advisors/Committee Members: Heckman, Carol.
Subjects: Biology; Cellular Biology; Molecular Biology
Keywords: Filopodia; Haptotaxis; Cdc42; Cell polarity; Ruffles; BioPORTER
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5.
Asbrock, Christina Marie.
INFLUENCE OF A MIXTURE OF TWO POLYCHLORINATED BIPHENYLS (PCB 47/77) ON PRO-INFLAMMATORY CYTOKINES (IL-6, TNF-á) AND ASSOCIATIVE BEHAVIOR IN YOUNG SPRAGUE-DAWLEY RATS.
Degree: MS, Biological Sciences, 2006, Bowling Green State University
► Polychlorinated biphenyls (PCB), are a group of 209 structurally related chemical compounds…
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▼ Polychlorinated biphenyls (PCB), are a group of 209 structurally related chemical compounds (congeners), that were once used in industrial applications, particularly as electrical insulating fluids and as heat exchange fluids, until concern regarding possible adverse effects on the environment and human health resulted in the cessation of production and an ultimate ban on manufacture in most countries. Upon the discovery of PCB in the environment, accounts of human exposure were investigated. PCB have been reported to cause a variety of health effects including immunologic, teratogenic, reproductive, carcinogenic, and neurologic. They are not only a potential health threat to adults, but also to developing fetuses and infants because they cross the human placenta and are found in human milk. In the present study, a simple mixture of PCB congeners, noncoplanar (PCB 47) and coplanar (PCB 77), were administered to young Sprague-Dawley rats by route of maternal dietary consumption (either 12.5 ppm or 25.0 ppm, w/w). Alterations in pup body, organ, and endocrine gland weight were determined on PND 15. Performance in conditioned odor preference (COP) tests and conditioned approach tests (CAT) was determined on PND 14 to examine the effects of PCB on the associative behavior of young rats. On PND 15, serum concentrations of circulating pro-inflammatory cytokines (IL-6, TNF-á) were determined using enzyme-linked immunosorbent assay (ELISA). Concentration of both IL-6 and TNF-á in serum were found to be positively correlated to administered PCB 47/77 concentration. Significant behavioral effects involving associative behavior and odor preference not observed in the present study. However, body weights at PND 15 were significantly depressed in animals exposed to PCB 47/77, and may be a physical symptom of sickness behavior that may have further been enhanced by the increased pro-inflammatory cytokine levels observed in the present study.
Advisors/Committee Members: Meserve, Lee A.
Keywords: PCB 47 77; pro-inflammatory cytokines IL-6 TNF; sprague-dawley; associative behavior
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6.
Azad, Priti.
The Role of New Mutations in Evolution and Cloning: Genetic Analysis to Identify the Role of New Beneficial Mutations in Increasing Viability and Salt Tolerance in Drosophila Melanogaster and the Influence of Deleterious Mutations on Cloning Efficiency.
Degree: PhD, Biological Sciences, 2006, Bowling Green State University
► Mutation and selection are major driving forces of evolution. However, the role…
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▼ Mutation and selection are major driving forces of evolution. However, the role of new beneficial mutation is considered negligible in almost all evolutionary processes. In most cases it is difficult to separate the effect of pre-existing genetic variation at low frequencies from new mutations. In this study, experiments with Drosophila melanogaster were conducted to study the effect of new beneficial mutations on increases in viability and in adaptation to increased toxic levels of dietary salt. Completely homozygous stocks were used in the experiments to eliminate the effect of pre-existing genetic variation. In the viability experiment, a modification of Dobzhansky and Spassy assay (1947) was used to demonstrate that new beneficial mutations can quickly increase viability in Drosophila populations of different sizes. By use of inbred homozygous stock it was demonstrated that adaptation of Drosophila to increased salt tolerance due to new beneficial mutations can also occur quickly. We have also documented that the accumulation of deleterious mutations can reduce cloning efficiency in somatic cells. Overall, the results of these studies support the view that new mutations along with selection can have a major influence on cloning and the evolution of organisms.
Advisors/Committee Members: Woodruff, Ron C.
Subjects: Biology, Genetics
Keywords: new beneficial mutations, selection, salt tolerance, cloning
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7.
Bambakidis, Theodore.
Changes in Benthic Algal Community Structure Following an Unpredictable Stream-Wide Desiccation Event.
Degree: MS, Biological Sciences, 2009, Bowling Green State University
► Global climate models predict future temperature and precipitation conditions that will increase…
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▼ Global climate models predict future temperature and precipitation conditions that will increase the likelihood of unpredictable drought in currently perennially-flowing stream ecosystems. In this study, an experiment using artificial streams examined the impact that unpredictable desiccation and rehydration have on lotic periphyton community structure. 23 day-old periphyton communities were slowly desiccated and rehydrated over the course of two weeks, and changes in cell density and community composition were analyzed. Results indicated that a catastrophic loss of cell density occurred during desiccation, as most diatoms were eliminated and blue-green and green algal densities were severely depressed. The remaining desiccated periphyton community was dominated by blue-green, and to a lesser extent, green algae. After a 24-hour rewetting period, a 3-fold increase in cell density occurred and blue-greens continued to dominate the community. Immigration analysis indicated that immigrant cells could not have been solely responsible for the increase in cell density, suggesting that reproduction was more important during recovery. Cell health data revealed unique kingdom-specific responses to desiccation: diatom cells were empty, green algae exhibited some cellular damage, and blue-green algal cells were mostly healthy. The results of this study suggest that in streams that lack any history of seasonal desiccation, catastrophic loss of all periphyton occurs during drought, but blue-green and green algae are relatively better at surviving and recovering from desiccation than diatoms.
Advisors/Committee Members: Lowe, Rex.
Subjects: Ecology; Freshwater ecology
Keywords: periphyton; benthic algae; diatoms; cyanobacteria; desiccation; drought; streams; lotic
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8.
Barnes, Jami R.
An Integrative Approach to Conservation of the Crested Caracara (Caracara Cheriway)in Florida: Linking Demographic and Habitat Modeling for Prioritization.
Degree: PhD, Biological Sciences, 2007, Bowling Green State University
► The Crested Caracara (Caracara cheriway) occurs in Florida as an isolated population…
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▼ The Crested Caracara (Caracara cheriway) occurs in Florida as an isolated population in the south-central region. Caracaras currently occur almost exclusively on ranchlands, most of which are privately owned. The status of Florida's Caracara population has been a subject of concern as conversion of grasslands and pasture to residential and commercial development has accelerated, particularly within the past 10 years. Our objectives for this work were to provide a better understanding of the specific ecological needs of the Caracara with regard to habitat and to use known demographic information to develop a population model suitable for assessment of extinction risk. To achieve this, we used population viability analyses and a GIS. Using all available data, we constructed a population viability model to determine the most important demographic parameters and assess viability. The most important demographic variable impacting viability was adult survival, and our demographic model indicated that this population is stable under current conditions. However, current conditions are unlikely to persist and multiple habitat loss scenarios were explored. Results indicate abrupt habitat loss increases risk compared to gradual loss of the same magnitude. Using GIS, we evaluated habitat composition of known caracara home ranges and used the Mahalanobis distance statistic to build a predictive habitat model. Geographic layers used were recoded to reflect the landscape context surrounding each cell within an average home range. Models were tested using an independent data set. Results indicated that heterogeneity is critical and we identified seven landscape characteristics, including five vegetation types and both lentic and lotic water, necessary in maintaining suitable habitat in Florida. Our final habitat model performed well in both predictive accuracy and in reducing the portion of the study area judged suitable. Finally, we used occurrence data to identify distribution patterns of habitat use. A core area of habitat use was readily identified, and habitat use decreased consistently across buffers extending out from the core. This was integrated with our demographic and habitat models to prioritize habitat for conservation, and construct models simulating habitat loss in particular regions in Florida and their associated risk of population decline.
Advisors/Committee Members: Root, Karen V.
Subjects: Biology, Ecology
Keywords: Caracara; Florida; Conservation; Predictive Habitat Modeling; Population Viability Analysis; GIS
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9.
Baumgardner, Mary C.
FOREST FRAGMENTATION AND ITS EFFECTS ON ARTHROPOD POPULATIONS IN SMALL VS. LARGE FORESTS IN NORTHWEST OHIO.
Degree: MS, Biological Sciences, 2007, Bowling Green State University
► The loss of biodiversity is a large challenge facing the conservation biologist.…
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▼ The loss of biodiversity is a large challenge facing the conservation biologist. Many species of arthropods are susceptible to displacement, starvation or complete decimation when human activities, such as development, occur within or near their habitat. Insects and arthropods are not valued by the average person and are typically considered to be a frightening nuisance. The value of arthropods cannot be overstated. Arthropods perform services for ecosystems that are needed by plants and other organisms. For example, the elimination of insect pollinators would halt much of plant fruit and seed production and cause a reduction in plant repopulation. Detritivorous insects are vital to plants for their distribution of nutrients into soil. Larger forested areas should contain a greater abundance of arthropods and more species than smaller forests, according to the theory of island biogeography. The theory of island biogeography involves the study of distribution of species and community composition on islands. Various patches of small and large forests suggest islands of different sizes (Smith and Smith 2001). I calculated species richness, arthropod abundance and graphed species to forest area comparisons. My nine study sites varied from 1.6 to 1500 hectares. Most of the sites were surrounded by agricultural areas with roads or highways bordering one or more sides of the forests creating a possible barrier. Some of the larger sites also had roads cutting through the forest. Arthropods were sampled four times at each of the nine study sites in late spring and summer of 2005 and 2006 using the beat-stick method for collection. Once arthropods were placed into a zippered plastic bag with the sample of the tree or shrub and preserved in the freezer until sorting and identification could begin. There was little variation in abundance or species richness; small forests tended to have only slightly higher abundance numbers than the larger forest sites. The only group of insects that showed greater species richness in small vs. large forests was the order Orthoptera (p<0.05). Sorensen’s Similarity Index showed low similarity in study sites. The results of this study could be useful in land management; more studies need to be completed to aid in the total understanding of species distribution, community structure and optimal habitat requirements for arthropods.
Advisors/Committee Members: Pavuk, Dan M.
Keywords: fragmentation, arthropods, forest
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10.
Bekker, Kent A.
Comparative Growth and Demographics of Two Sympatric Natricine Snakes.
Degree: MS, Biological Sciences, 2007, Bowling Green State University
► The northern water snake, Nerodia sipedon and the queen snake, Regina septemvittata,…
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▼ The northern water snake, Nerodia sipedon and the queen snake, Regina septemvittata, are two species of the subfamily Natricinae that occur sympatrically throughout much of their ranges in Ohio. Regina septemvittata does not appear to be as abundant as it once was in much of its range, and published natural history information is lacking. Nerodia sipedon, however, has exhibited no decrease in abundance, and there is a relative abundance of published natural history information on this species. This study compares growth and population size for both species utilizing mark-recapture techniques and skeletochronology at the Sandusky Bay Fishing Access Site in Ottawa County, Ohio. The Sandusky Bay fishing access site supports populations of the following snake species: the northern water snake, Nerodia sipedon, the queen snake, Regina septemvittata, the eastern garter snake, Thamnophis sirtalis, Butler’s garter snake, Thamnophis butlerii, the eastern fox snake, Elaphe gloydi, and Dekay’s snake, Storeria dekayi. Population estimates for Nerodia sipedon result in densities similar to published values for nearby populations. Population estimates for Regina septemvittata displayed a decline over the course of the study, which was mirrored in the relative abundance of queen snake within the total sample for each year. Growth has an impact on snake conservation through delayed maturation, longer time spend at a size class experiencing a higher rate of mortality, and reduced reproductive advantage. Nerodia sipedon is growing faster than most of the previously published rates, and growth rates are similar to those experienced in Lake Erie populations since the introduction of the round goby. Regina septemvittata females and juveniles are growing slower than the previously published values. Skeletochronology was used to age individuals via lines of arrested growth (LAG) in bones. Tail vertebrae were sampled in an attempt to age individuals of both Nerodia sipedon and Regina septemvittata. There was no correlation between snout-vent length and number of LAGs. There was very little agreement between multiple investigators with respect to the number of LAGs counted within a single sample. The results of this study suggest an overall decline in the queen snake, Regina septemvittata and a stable population of the northern water snake, erodia sipedon, at the Sandusky Bay location. The difference in growth rates between this study and previously published values for both species may be influenced by the introduction of round gobies.
Advisors/Committee Members: Pavuk, Daniel M.
Subjects: Biology, Ecology
Keywords: Regina; septemvittata; Nerodia; sipedon; growth; demographics
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11.
Belanger, Rachelle Marie.
An Interdisciplinary Investigation of the Role of Crayfish Major Chelae in the Discrimination of Conspecific Odours: from Morphology to Behaviour.
Degree: PhD, Biological Sciences, 2007, Bowling Green State University
► This dissertation examines the use of the major chelae by male crayfish…
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▼ This dissertation examines the use of the major chelae by male crayfish ( Orconectes rusticus) for discrimination and localization of female odours and links this behaviour with sensory setae morphology and distribution. First, a behavioural bioassay was implemented to test whether male reproductive (form I) and non-reproductive (form II) crayfish use their major chelae to detect and discriminate reproductive female odours. Behavioural reactions of male crayfish, with intact or sensory blocked chelae, were recorded to four different odour treatments: female-conditioned water, male-conditioned water, fish homogenate, and water (control). Intact form I males handled the female odour source significantly more (46.4 ± 17.0 seconds) than blocked and form II males. Next, the role of sensory information from the major chelae in the localization of reproductive female odours was examined. Behavioural reactions of intact and blocked form I male crayfish were analyzed in response to three different odour treatments: female-conditioned water, male-conditioned water, and water (control) delivered from one end of a test arena. Large-scale movements and chemosensory sampling behaviours were measured. Male crayfish with intact major chelae spent more time (45.4 ± 7.7 %) closer to the odour source when the reproductive female odour was delivered compared to all other odours. Also, intact male crayfish spent more time chelae waving (61 %) in response to female odours than blocked males. Lastly, a comparative and morphological analysis of setae found on the major chelae of form I and II male crayfish was performed. To accomplish this, scanning electron microscopy, a permeability assay, anterograde labelling, and acetylated tubulin (AT) immunocytochemistry were used. Results show that form I crayfish had more sensory setae pockets and individual smooth setae on their major chelae compared to form II males. Also, smooth setae contained a terminal pore, were crystal violet permeable, and contained anterogradly labelled DiI and AT positive nerve fibers. Conversely, plumose setae lacked a terminal pore, did not label with DiI, and were crystal violet and AT negative. Overall, these results suggest that the major chelae are important sensory structures needed for the localization and discrimination of female odours and may be important for reproductive behaviours such as mate recognition.
Advisors/Committee Members: Moore, Paul A.
Keywords: crayfish, mating, major chelae, behaviour, morphology, reproduction
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12.
Benson, Jennifer.
Effect of the DNA Methylation Inhibitor 5-aza-2'-Deoxycytidine on the Virulence of the Soybean Pathogen Phytophthora Sojae.
Degree: MS, Biological Sciences, 2012, Bowling Green State University
► Phytophthora sojae is an oomycete plant pathogen classified in the Stramenopile kingdom.…
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▼ Phytophthora sojae is an oomycete plant pathogen classified in the Stramenopile kingdom. It specifically targets the soybean crop plant. Infection by P. sojae causes ‘damping off' in seedlings and root rot in older plants. The main form of dispersal is a motile zoospore released when the oomycete is under nutrient or water stress. Diverse gene regulation mechanisms control growth, development, virulence and dispersal of zoospores. Due to the pathogen's ability to rapidly adapt, it is thought that not only genetic but also epigenetic signaling plays a role in P. sojae growth and virulence. The focus of this study is to investigate epigenetic gene regulation mechanisms employed by P. sojae via DNA methylation and its effect on pathogenicity. Treatment with 5-aza-2'-deoxycytidine, a DNA methyltransferase inhibitor, altered hyphal growth rates, zoospore morphology, gene expression, and infection pattern, possibly due to a loss of methylation.
Advisors/Committee Members: Phuntumart, Vipaporn.
Subjects: Agriculture; Biochemistry; Biology; Botany; Genetics; Plant Biology; Plant Pathology; Plant Sciences
Keywords: epigenetics, oomycete, soybean, DNA methylation, methyltransferase, 5-aza-2'-deoxycytidine, phytophthora, P. sojae
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13.
Bergolc, Melanie L.
The Coleopteran Fauna of Sultan Creek-Molas Lake Area with Special Emphasis on Carabidae and how the Geological Bedrock Influences Biodiversity and Community Structure in the San Juan Mountains, San Juan County, Colorado.
Degree: PhD, Biological Sciences, 2009, Bowling Green State University
► Few studies have been performed on coleopteran (beetle) biodiversity in mountain ecosystems…
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▼ Few studies have been performed on coleopteran (beetle) biodiversity in mountain ecosystems and relating them to multiple environmental factors. None of the studies have examined geologic influences on beetle communities. Little coleopteran research has been performed in the Colorado Rocky Mountains. The main objectives of this study were to catalog the coleopteran fauna of a subalpine meadow in the San Juan Mountains of Colorado and investigate the role geology had in the community structure of the Carabidae (ground beetles). The study site, a 160,000 m2 plot, was located near Sultan Creek and Molas Lake in San Juan County, Colorado. Five sites were in each bedrock formation: Molas, Elbert, and Ouray-Leadville. Insects were collected via pitfall trapping in 2006 and 2007, and identified by comparison with museum specimens, museum and insect identification websites, and by taxonomic experts. Biological and physical factors were recorded for each site: detritus cover and weight, plant cover and height, plant species richness, aspect, elevation, slope, soil temperature, pH, moisture, and compressive strength, and sediment size distribution. Quantitative analyses were performed on the Carabidae community and its relationship to bedrock formations and environmental factors measured, and on the entire coleopteran abundance and its relationship to the environmental factors. I sampled 7,316 coleopteran individuals in 27 families and nearly 100 species (61 completely identified). Coleopteran abundance was influenced by plant cover, plant height, soil moisture, aspect, slope, collection site, and week collecting took place. A total of 1,236 carabid individuals representing 30 species were collected. Elevation, detritus cover, and soil temperature were significantly distinct between formations. Species richness and abundance of several species (Agonum placidum, Bembidion mutatum, Carabus taedatus, Cymindis cribricollis, Harpalus animosus, and Harpalus laticeps) differed significantly between formations, but overall there were no distinct carabid communities associated with the three formations. Carabid species richness, abundance, and biodiversity were significantly influenced by plant factors, and frequency was significantly influenced by sediment sorting. The carabid species composition was influenced (not significantly) by compressive strength, pH, plant cover, soil moisture, slope, and aspect. In conclusion, geology had less of an effect on carabidae then other environmental factors.
Advisors/Committee Members: Pavuk, Daniel.
Subjects: Ecology
Keywords: Coleoptera; Carabidae; Colorado; Community Ecology; Geology; Bedrock; San Juan Mountains
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14.
Boehler, Christopher Thomas.
Classifying Hatchery Steelhead Trout Stocks Using Otolith Chemistry: Spatial and Temporal Distribution of Adult Steelhead Trout.
Degree: MS, Biological Sciences, 2010, Bowling Green State University
► The salmonid fishery in Lake Erie is sustained by the stocking of…
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▼ The salmonid fishery in Lake Erie is sustained by the stocking of ~2 million steelhead trout smolts (Oncorhynchus mykiss; MI 60,000; NY 250,000; OH 450,000; & PA 1,100,000) annually into tributaries of the four adjoining states. To better understand the mixed stock distribution in the lake and the dynamics of returning adult steelhead to their release tributaries, large scale marking of hatchery smolts is needed. Microchemical signatures of smolt otoliths measured by laser-ablation-inductively-coupled-plasma-mass-spectrometry (LA-ICPMS) were used to identify each hatchery stock. The state-specific hatchery stocks were identified with high confidence using discriminant analysis (included Sr and Ba concentrations in three otolith regions) and jackknifed validation (OH 100.0%, MI 93.1%, NY 96.3%, & PA 93.9% correct assignment). One Lake Erie tributary, Conneaut Creek, provides a unique opportunity to determine the extent of site fidelity of adult steelhead trout because it is equally stocked by both OH and PA each spring. Returning steelhead trout (N = 174) were collected from two different Conneaut Creek sites, Conneaut OH (2 km from Lake Erie) and Albion PA (40 km from Lake Erie), in the spring (April) and fall (November) of 2009. The hatchery stocks from different states were identified using the microchemistry of their otoliths. Classification results of a discriminant analysis (DA) based on elemental concentrations (ppm) of both Sr and Ba from returning adult steelhead are as follows: 32.8% OH, 60.9% PA, 1.7% NY, 0.6% MI, and 4.0% unknown (Total N = 174). Ohio stocked steelhead were collected in both the spring and fall at the Conneaut OH site, but no OH stocked steelhead were collected at the PA site in either the spring or fall. This demonstrates strong within stream stock partitioning between the OH and PA stocked steelhead. Percentages of vagrancy of the total classified adult steelheads collected from hatchery sources not stocked in Conneaut Creek were 2.3% (1.7% NY and 0.6% MI). Because the state-specific hatchery stocks could be accurately distinguished an opportunity is provided for fisheries biologists to gain knowledge of the mixed stock distribution and site fidelity of steelhead trout in Lake Erie.
Advisors/Committee Members: Miner, Jeffrey.
Subjects: Ecology; Freshwater ecology; Geochemistry
Keywords: steelhead, trout, otolith chemistry, Lake Erie, Great Lakes, salmonid, stock, site fidelity
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15.
Boyanapalli, Ramakrishna Bharadwaj.
Construction and Characterization of Cyanobacterial Bioreporters to Assess Nutrient (P, Fe) Availability in Marine Environments.
Degree: PhD, Biological Sciences, 2006, Bowling Green State University
► Nutrient deficiency especially phosphorus (P) and iron (Fe), are well documented in…
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▼ Nutrient deficiency especially phosphorus (P) and iron (Fe), are well documented in world oceans, particularly associated with oligotrophic oceanic gyres and “high nutrient, low chlorophyll” (HNLC) regions. As a corresponding approach to identify bioavailable Fe in marine systems, my research has focused on the development, characterization and implementation of a whole-cell cyanobacterial Fe bioreporter to be used to assess the bioavailability of Fe in marine environments. A Fe responsive whole-cell marine bioreporter was developed by integrating a construct of the isiAB promoter fused to bacterial luciferase luxAB into the marine cyanobacterium Synechococcus PCC 7002. Dose-response characterization of the bioreporter was made in trace-metal buffered synthetic seawater medium containing Fe concentrations in the range of pFe [-log (Fe3+ free ferric)] 19.4 – 22.4. The luminescent response from the Fe bioreporter was best described by a sigmoidal dose-response curve. A comprehensive growth and physiological characterization of the bioreporter was conducted prior to implementing it to assess Fe bioavailability from various marine samples. The bioreporters response was optimum when it was incubated at 25 °C under an irradiance of 45 µmol photon m-2 s-1. Varying the amount of bioreporter inoculum or salinity of the test medium did not affect cellular luminescence over the 12 h assay period. Testing the ability of the bioreporter to acquire Fe3+ bound to ligands, the bioreporter was able to acquire bound Fe from rhodotorulic acid but, was unable to acquire Fe from ligands such as desferrioxamine B and N, N’-diethylenediamine-N,N’-diacetic acid. We assessed Fe availability in environmental samples from the Baltic Sea using the cyanobacterial bioreporter and demonstrated that the bioavailable Fe was one order of magnitude lower than the chemically-determined dissolved Fe and that samples from depth showed higher available Fe than at the surface. The Fe bioreporter was also implemented for assessing available Fe in samples collected during the mesoscale Fe fertilization experiment SERIES conducted in the HNLC eastern subarctic Pacific Ocean, and in samples collected from oligotrophic waters of the central north Pacific gyre during the ROMP study. The luminescent response from these open ocean samples was consistently higher than the corresponding calibration standard. As a result, the cyanobacterial Fe bioreporter can only be considered a qualitative tool with which to assess Fe availability in open ocean environments. Despite this constraint, we observed genuine differences in Fe availability from samples collected during each study.
Advisors/Committee Members: McKay, Michael L.
Keywords: Bioreporter, Cyanobacteria, Synechococcus PCC 7002, Iron, Bioavailability, Iron Chelators, Oxidative Stress, isiAB, luxAB, luciferase
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16.
Breidenbach, Carl R.
Phospholipid Dependency of Membrane-Associated Pyridine Nucleotide-Utilizing and Succinate Dehydrogenase Activities of Adult Hymenolepis Diminuta (Cestoda) and Ascaris Suum (Nematoda).
Degree: MS, Biological Sciences, 2012, Bowling Green State University
► The adult intestinal cestode, Hymenolepis diminuta, is essentially anaerobic in its metabolism…
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▼ The adult intestinal cestode, Hymenolepis diminuta, is essentially anaerobic in its metabolism and generates ATP without the need for oxygen. H. diminuta relies upon a mitochondrial NADPH->NAD transhydrogenase to link the NADPH produced by the pyruvate-forming arm of the malate dismutation reaction, catalyzed by the mitochondrial “malic enzyme”, with the NADH-requiring, anaerobic electron transport system. The electron transport-coupled fumarate reductase serves to reduce fumarate, the terminal electron acceptor, to succinate. A phospholipid dependency was established previously with respect to the transhydrogenase, fumarate reductase, and the lesser NADH oxidase. Of the phospholipids assessed, the transhydrogenase exhibited a phosphatidylcholine preference. The present study expands on prior findings by using phospholipase A1, A2, C and D, organic solvent, and ammonium sulfate treatments of H. diminuta mitochondrial membranes. Other reduced pyridine nucleotide-utilizing systems viz., NAD(P)H cytochrome c reductase, NADH->NAD transhydrogenation, NAD(P)H-, and lipoamide dehydrogenase activities as well as succinate dehydrogenase were evaluated. A comparative study also was undertaken by treatment with the phospholipases of isolated mitochondrial membranes from the anaerobic intestinal nematode, Ascaris suum. The data presented indicate a phospholipid dependence not only of the previously reported systems, but of membrane-associated mitochondrial systems in H. diminuta and A. suum. H. diminuta NADH cytochrome c reductase displayed phospholipid dependence based on phospholipase A2 and C treatments, and a neutral lipid dependence based on organic solvent treatments. Ammonium sulfate fractionation had little effect. Succinate dehydrogenase activity displayed phospholipid dependence based on phospholipase C and organic solvent treatments. Ammonium sulfate fractionation decreased succinate dehydrogenase activity, but phosphatidylcholine supplementation further diminished activity. A. suum NADH cytochrome c reductase, NADH oxidase and fumarate reductase systems exhibited phospholipid dependence based on phospholipase A2 and C treatments. Interestingly, A. suum succinate dehydrogenase appeared more resistant to phospholipase treatment than the corresponding H. diminuta system.
Advisors/Committee Members: Fioravanti, Carmen.
Subjects: Biochemistry; Biology; Parasitology
Keywords: Hymenolepis diminuta; Ascaris suum; mitochondria; parasite; phospholipid; phospholipase; phospholipid depletion; anaerobic electron transport; tapeworm; roundworm
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17.
Brinkman, Kerry K.
USING CHIMERAS TO EVALUATE CROSS-TALK, ENERGY TRANSFER, AND PROTEIN-PROTEIN INTERACTIONS IN THE TONB AND TOLA SYSTEMS.
Degree: PhD, Biological Sciences, 2007, Bowling Green State University
► The cytoplasmic membrane (CM) protein TonB energizes transport of ferric siderophores and…
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▼ The cytoplasmic membrane (CM) protein TonB energizes transport of ferric siderophores and group B colicins across the gram-negative outer membrane, and confers sensitivity to certain bacteriophages. These functions depend upon heteromultimeric protein complexes that couple TonB to the ion electrochemical potential of the CM. This is most efficient when TonB interacts with the ExbB/ExbD complexes; however, the ExbB/ExbD paralogues TolQ/TolR can also support TonB-dependent processes, albeit less efficiently. Strains bearing specific deletions of exbB, exbD, tolQ, and tolR were generated and their ability to support TonB function determined. When only ExbB/D was present, activity mirrored that of the wild-type strain, but was diminished when only TolQ/R was present. Low activity was evident for the mixed complex ExbB/TolR, but not for the TolQ/ExbD complex. In vivo cross-linking indicated that ExbB interacted with TonB independent of the presence of either ExbD or TolR. TonB stability is greatly decreased in the absence of the ExbB/D complex. Here, ExbB alone, or with TolR, was sufficient for the stability of TonB. TolQ alone, or with ExbD, also stabilized TonB, despite the absence of ExbB. Together, these data suggest that the ExbB/TolQ component of a given complex is sufficient for interaction with TonB, but the ability to couple TonB to the ion gradient of the membrane requires interactions between the ExbB/TolQ and ExbD/TolR components of the complex. These data suggest that instability results from activity and TonB interactions at the CM are dependent upon varying conformational states. Like TonB, TolA is most efficient when it interacts with its heterologous energy harvesting complex (TolQ/R) and in its absence is less efficiently supported by ExbB/D. Because TonB and TolA each have a “preferred” energy-harvesting complex, it is clear motifs not shared between TonB and TolA are involved in interactions with energy harvesting complexes. Testing two distinct TolA/TonB chimeric proteins provides a different view of how the transducers in the TolA and TonB systems interact with the energy harvesting complexes. These new data suggest that the transmembrane domains of these two transducers may not be solely responsible for energization.
Advisors/Committee Members: Larsen, Ray A.
Keywords: TonB; TolA; Energy transduction; ExbBD; TolQR
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18.
Carver, Paula D.
Evidence of Possible Coupling Between Circadian Oscillators of the Mouse Lung.
Degree: MS, Biological Sciences, 2008, Bowling Green State University
► Circadian rhythms in gene expression have been detected in almost every organ…
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▼ Circadian rhythms in gene expression have been detected in almost every organ of mammals, including the lung. These rhythms appear to optimize daily physiological functions and are regulated by peripheral circadian oscillators in the organs. A major circadian pacemaker in the suprachiasmatic nucleus of the hypothalamus also controls the timing of the peripheral oscillators in part though the vagus nerve. This study provided evidence of possible coupling between circadian oscillators in lung tissue maintained in culture. It also tested whether acetylcholine treatments would mimic timing signals from the vagus nerve. Circadian rhythms in gene expression were monitored by imaging the bioluminescence from lung cultures made from mice that contain the mPer1::luc transgene. Acetylcholine at 50 µM had no affect on the period, phase, or luminescence intensity of the lung cultures. Maps of the period and phase of rhythms in the cultures were determined at each pixel of the bioluminescence images. The most frequent periods were 19.50 and 25.75 hours in cultures from two mice. The spatial distribution of phases found in the maps showed a clustering, and these phases were compared with the timing of the prior light cycle experienced by the mice. Phases ranged from one hour after dusk to one hour after dawn, in agreement with previous studies that identified an average peak in the lung circadian rhythm during the night. Changes in phase distributions between circadian cycles suggested that lung oscillators may interact to maintain a closely coupled state. Desynchrony between these oscillators could play a role in diseases of the human lung.
Advisors/Committee Members: Geusz, Michael.
Subjects: Biology; Biomedical research; Molecular biology
Keywords: Coupling; Circadian; Circadian Oscillators; lung; mouse; period; phase
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19.
Chakraborty, Arup Ratan.
Differential Expression of Integrin α3β1 and α6β4 Molecules on a Panel of Rat Esophageal Cell Lines.
Degree: MS, Biological Sciences, 2005, Bowling Green State University
► Integrins are heterodimeric transmembrane glycoproteins consisting of α and β subunits.Various studies…
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▼ Integrins are heterodimeric transmembrane glycoproteins consisting of α and β subunits.Various studies have discovered that integrins influence processes pivotal in carcinogenesis. Esophageal caner is a disease with a low survival rate. The main objective of this study was to determine the expression of α3β1 and α6β4 integrins on rat esophageal tumorigenic (RE-B2T, RE-C1T) and non-tumorigenic (RE-79, RE-149, RE-282) cell lines. Monoclonal antibodies against α3β1 and α6β4 integrins were used in this study. The expression of these integrin molecules was higher on non-tumorigenic cell lines than tumorigenic ones. It was concluded that in in vitro culture system, rat esophageal cells express α3β1 and α6β4 integrin molecules differentially. It appears that the expression of these two molecules is down-regulated in the invasive cell line, RE-B2T, compared to other non-tumorigenic or normal cell. This reduction in the expression may enhance tumor cell motility and contributes to the metastatic spread of tumor in vivo.
Advisors/Committee Members: Jamasbi, Roudabeh J.
Keywords: INTEGRIN; α3β1; CELL LINES; Esophageal cancer; carcinoma
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20.
Chen, Xing.
EVOLUTION OF GROUP I INTRONS IN THE NUCLEAR RIBOSOMAL RNA GENES OF DOTHIDEOMYCETES.
Degree: MS, Biological Sciences, 2010, Bowling Green State University
► Group I introns, as self-splicing ribozymes, have been very important in the…
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▼ Group I introns, as self-splicing ribozymes, have been very important in the evolution of fungi. In this study, a set of group I introns have been described within the nuclear small and large subunit rRNAs of several fungi. DNA extraction, ribosomal DNA amplification, sequencing, secondary structure analysis and phylogenetic analysis were performed, which led to the conclusion that the evolutionary history of group I introns has been processed as multiple insertions over a prolonged time by horizontal transmission, followed by the loss of the ability to insert into new loci, followed by an extended time of vertical inheritance, including reduction in size and loss of secondary structure segments, followed by the complete loss of group I introns.
Advisors/Committee Members: Rogers, Scott.
Subjects: Biology
Keywords: Group I intron, Secondary Structure, Phylogenetic tree
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21.
Chowdhury, Budhaditya.
Behavioral Genetic Characterization of Hunting in Domestic Dogs, Canis Familiaris.
Degree: PhD, Biological Sciences, 2011, Bowling Green State University
► Humans have exerted strong selection pressures for the behavioral attributes which make…
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▼ Humans have exerted strong selection pressures for the behavioral attributes which make dogs prized hunting companions, viz., superior sensory capabilities, social cognition, and tenacious pursuit of prey. With behavioral traits maintained in stable breed lines, and a unique genome organization, dogs are ideally suited for a genetic dissection of complex behavioral phenotypes. Despite studies employing substantial sampling regimes the promise of the canine model has yet to be realized, largely because of the dearth of robust quantitative behavioral metrics. Here we show that refined dissection of a complex behavior into component parts is instrumental in identifying genomic signatures associated with these elements. Using 11 spatially explicit measures we demonstrate the existence of four principal dispositions describing Search Eagerness, Linear Running, Handler Reliance, and Zigzagged Searching. A Single Nucleodide Polymorphic marker - based association study reveals that Search Eagerness significantly associates with genomic regions on chromosomes 1 and 27 (Chromosome wide significance, p [100,000 permutations] < 0.05). Adjacent are sites for brain specific Demethylase- (MBD2) and GABA transporter genes (BGT1, GAT2, GAT3) coding for transcriptional repressor proteins and regulating levels of extracellular neurotransmitters respectively. We anticipate that the wider application of such objective quantitative frameworks will improve the phenotypic characterization that remains the bottleneck in neurobehavioral genetic research.
Advisors/Committee Members: Huber, Robert.
Subjects: Biology
Keywords: Behavioral quantification; Genetic Analysis; Domestic dogs; Hunting instinct
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22.
Collaco, Anne.
Characterization of the Expression and Regulation of the Menkes Protein in an Adrenocorticotropic Tumor Cell Line and Rat Endocrine Tissues.
Degree: PhD, Biological Sciences, 2006, Bowling Green State University
► To ensure copper homeostasis, organisms express copper chaperones and the Menkes copper…
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▼ To ensure copper homeostasis, organisms express copper chaperones and the Menkes copper transporter (MNK). Mutations within the MNK gene result in MNK disease, characterized by neurodegeneration, cutis laxa, and hypopigmentation. These symptoms are attributed to a deficiency in copper delivery to cuproenzymes, such as peptidylglycine alpha-amidating monooxygenase (PAM). Fibroblasts transfected with MNK have copper-dependent MNK localization in the trans-Golgi network (TGN). Since MNK localization in neuroendocrine cells has not been investigated, this study examined MNK localization in adrenocorticotropic tumor wild type (AtT-20 WT) and PAM (AtT-20 PAM-1) cell lines by immunofluorescence microscopy, subcellular fractionation, and Western blot analyses. To analyze the effect of copper levels on MNK localization, cells were treated with CuCl2, the copper chelator, BCS, and BCS/CuCl2. Immunofluorescence microscopy confirmed that MNK localization is in the TGN in WT and PAM-1 control and BCS treated cells, while in CuCl2 treated cells, MNK showed TGN and diffuse staining throughout the cytoplasm. Sucrose density gradients from control cells showed MNK localization in TGN and secretory granules. A wider distribution of MNK into lighter fractions in these gradients was observed following copper treatments, indicating MNK trafficking is copper-dependent. In addition, developmental differences in MNK expression in rat brain and endocrine tissues also were examined by Western blot analyses and RT-PCR. In adrenals, MNK protein expression increased, whereas MNK mRNA remained unchanged. In the pituitary, hippocampus and cerebellum, MNK protein and mRNA decreased, while in the atria, they remained unchanged. Therefore, MNK mRNA was differentially expressed during development. Thus, little parallel between expression of MNK protein and mRNA was observed from postnatal day 3 to adult. Since secretagogues alter PAM expression and PAM activity requires copper delivery from MNK, this study also examined the MNK expression regulation by secretagogues. While MNK secretion was not stimulated, it was regulated by secretagogues. MNK expression was increased after treatment with PMA, CRH and cAMP, with a slight decrease after BaCl2 treatment. Overall, these studies have begun to shed light on how the endogenous MNK protein functions in cells expressing a cuproenzyme dependent on copper delivery from MNK.
Advisors/Committee Members: Steveson, Tami.
Subjects: Biology, Molecular
Keywords: Menkes; Peptidylglycine alpha amidating monooxygenase; MNK; PAM; localization; expression; endocrine cells
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23.
Cook, Michelle Elizabeth.
Environmental and social factors influence communication used during crayfish agonistic interactions.
Degree: MS, Biological Sciences, 2008, Bowling Green State University
► Agonistic interactions are mediated, in part, by communication between conspecifics. For crayfish,…
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▼ Agonistic interactions are mediated, in part, by communication between conspecifics. For crayfish, both chemical and visual communication have been shown to regulate aggression. Within each of these sensory systems are factors that influence communication used in agonistic interactions. Environmental factors such as toxins in aquatic ecosystems have the ability to disrupt chemical communication used during aggressive encounters. In the visual system, potential bystanders can extract relevant visual cues from interacting conspecifics and use them in future encounters.This thesis addresses two factors that influence chemical and visual communication used during crayfish agonistic encounters. In the first study, chemical communication was found to be impacted by sublethal exposure to metolachlor, a herbicide used in northwest Ohio. This research indicates that crayfish exposed to 80 ppb metolachlor were less likely to initiate and win encounters against naïve conspecifics. High sublethal concentrations of metolachlor may be interfering with the ability of crayfish to receive or respond to chemical signals and thus affect certain agonistic behaviors. In the second study, visual communication was investigated in the broader context of a communication network and related to the role of previous social history in shaping crayfish aggression. In the field, visual cues are important for crayfish as dyadic interactions often occur in the vicinity on non-participating individuals. By observing fights, these bystanders have the potential to extract relevant information about future opponents. Results indicate that previous social history was more influential in determining fight outcome than information gathered via visual signals. Crayfish use a combination of sensory cues, including chemical signals, during social interactions. Thus, visual information independent of other sensory cues may not provide the proper context for information use in subsequent interactions. Crayfish use both chemical information and visual information during agonistic encounters and by examining how each sensory system shapes crayfish aggression, the mechanisms can be further understood.
Advisors/Committee Members: Moore, Paul.
Subjects: Biology; Ecology
Keywords: crayfish, agonistic interactions, communication networks, metolachlor
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24.
Coulianos, Natalie N. G.
A comparison of ALA synthase gene transcription in three wild type strains of Rhodobacter sphaeroides.
Degree: MS, Biological Sciences, 2011, Bowling Green State University
► The common precursor to all tetrapyrroles, essential biomolecules that include hemes, chlorophylls,…
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▼ The common precursor to all tetrapyrroles, essential biomolecules that include hemes, chlorophylls, and corrinoids, is 5-aminolevulinic acid (ALA). In the facultative phototroph Rhodobacter sphaeroides, ALA formation is catalyzed by ALA synthase. Not all strains of R. sphaeroides have the same genomic content of ALA synthase genes; wild type strains 2.4.1 and 2.4.9 have two, hemA and hemT, while strain 2.4.3 has only one, hemA. The upstream regions of hemA and also hemT (when present) differ among these strains, which suggest their expression may not be the same in every strain. Therefore, to understand how the cell produces the proper amounts of ALA to support growth, while maintaining adequate metabolic flexibility, investigations into the significance of these differences were carried out using lacZ transcription reporter plasmids involving the upstream sequences of the ALA synthase genes from all three strains. The assays of β-galactosidase activities in strains harboring the reporter plasmids indicate that for hemA, transcription is upregulated in the absence of oxygen in all three strains, but the amplitude of induction is different; induction in wild type 2.4.3, which relies exclusively on hemA to fulfill its ALA requirements, is highest. For hemT, the assays confirmed that in strain 2.4.1 hemT is transcriptionally silent, while in strain 2.4.9 it is active and upregulated under anaerobic-dark/DMSO conditions. Two sigma factor genes in strain 2.4.9 are absent from strain 2.4.1, and so may be responsible for promoting hemT transcription; for one of them, fecI, a consensus promoter-like sequence was identified within the hemT upstream sequence. Alterations to that sequence reduced hemT transcription. Transcription of hemT was also found to respond to iron availability, as is true of FecI-dependent transcription in other bacteria, providing further support for the idea that hemT transcription is promoted by, at least, the FecI sigma factor. In vitro studies revealed that the hemT transcript is short-lived, which will necessitate the use of non-standard 5' mapping methods to precisely locate the hemT promoter. This work has demonstrated that the patterns of hemA and hemT transcription are not uniform among wild type strains of R. sphaeroides. Apparently, as these bacteria have evolved to have distinct physiologies, the regulated production of ALA has been tailored in each to match their individual requirements.
Advisors/Committee Members: Zeilstra-Ryalls, Jill.
Subjects: Biology; Microbiology; Molecular Biology
Keywords: Rhodobacter sphaeroides; hemA; hemT; 5-aminolevulinic acid; 5-aminolevulinic acid synthase
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25.
Coulter, Melanie.
A multi-spatial-scale characterization of Lark Sparrow habitat and the management implications.
Degree: MS, Biological Sciences, 2008, Bowling Green State University
► Habitat requirement studies of endangered species often examine only one spatial scale…
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▼ Habitat requirement studies of endangered species often examine only one spatial scale since more lengthy multi-scale studies can delay conservation. However, not considering multiple scales could cause crucial habitat components to be overlooked, reducing the chances of successful conservation.I designed a single season, multi-spatial-scale study of the habitat use of the state endangered Lark Sparrow in the Oak Openings Region of Northwest Ohio. This rapid assessment technique can be applied to species of concern to gain a detailed assessment of habitat requirements in a short amount of time. I assessed Lark Sparrow habitat requirements at three spatial scales: landscape, habitat patch, and territory. To characterize Lark Sparrow habitat, I compared the landscape context and vegetation structure of presence sites and absence sites. Presence sites were active breeding sites, and absence sites were former breeding sites that Lark Sparrows abandoned. The results suggest that Lark Sparrows responded to different habitat parameters at different spatial scales. At the landscape scale, patch size and shape were important. At the habitat patch scale, percent tree cover and vegetation height-density were important. At the territory scale, percent tree cover, percent shrub cover, vegetation height-density, and proximity to occupied territories were important. Studying a single spatial scale would have produced an incomplete picture of breeding Lark Sparrow habitat. The habitat Lark Sparrows use in the Oak Openings is Midwest sand barrens, a globally rare early-successional plant community. I assessed the effectiveness of restoration efforts for Midwest sand barrens and Lark Sparrow habitat by comparing the land management histories of active breeding sites and abandoned breeding sites. The number of management events (i.e. mowing and prescribed burns) in the most recent three years was significantly higher for active sites. These results suggest that habitat change happens quickly in Midwest sand barrens. If a site is not managed at least once every three years, it will cease to function as an early-successional habitat, and Lark Sparrows will abandon it. Managing sand barrens frequently enough to support successful Lark Sparrow populations will benefit the suite of early-successional specialists that inhabit the unique Midwest sand barren plant community.
Advisors/Committee Members: Root, Karen.
Subjects: Biology; Ecology
Keywords: habitat model; habitat use; multiple spatial scales; landscape; avian habitat; savanna; Lark Sparrow; Oak Openings; early-successional
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26.
Cramer, Todd James.
Genetic Mosaicism Between The Bacteriophage φ80 And Bacteriophage λ.
Degree: MS, Biological Sciences, 2008, Bowling Green State University
► Mosaicism may occur among the genomes of organisms as well as the…
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▼ Mosaicism may occur among the genomes of organisms as well as the viruses or bacteriophage that infect them. Some of these changes result from mutations, insertions, deletions, hybridization, generalized or specialized transduction, transformation, and conjugation. These changes to the genome often lead to strains and/or species different from the original. Comparing sequences of these new forms of the genome to their purported origins can help us further understand the evolutionary links between them and how they may have diverged. As bacteriophage lack ribosomal RNA, and no other universal characteristic exists that allows comparison of many different bacteriophage species to each other, it is clear that genomic and proteomic comparisons will play an invaluable role in the future of bacteriophage phylogenetics. The bacteriophage φ80 has an ~45,000 nucleotide linear dsDNA genome and infects several Gram-negative bacteria, including Escherichia coli, exploiting proteins in the bacteria’s outer membrane for host recognition and the bacterial cell itself for reproduction. The bacteriophage φ80 is a lambdoid bacteriophage, genetically and morphologically related to bacteriophage λ, which also infects E. coli. As φ80 and λ utilize different receptors for host recognition, it is likely that their respective genomes will differ in at least those aspects of the genomes that dictate host range specificity. Many other bacteriophage also infect E. coli, and it is possible that co-infection may occur. When this happens, recombination and reorganization between genomes may occur, creating a new version when viable progeny are released. By comparing the approximately forty percent (40%) of the known sequences of the genome of φ80 to already completed sequences of λ and other lambdoid and non-lambdoid bacteriophage, a clearer understanding of how these two bacteriophage are related has emerged and suggests that they are not as similar as previously assumed. The data presented here suggest that although φ80 is related to λ phylogenetically, its genome has diverged from the genome of λ considerably over a relatively short amount of time.
Advisors/Committee Members: Larsen, Ray.
Subjects: Genetics
Keywords: genetics; mosaicism; bacteriophage; λ; φ80
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27.
Crouch, Ryan T.
Adding value to upground drinking water reservoirs: what makes a good yellow perch (Perca flavescens) fishery?.
Degree: MS, Biological Sciences, 2011, Bowling Green State University
► Upground reservoirs exist primarily as drinking water storage but also are managed…
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▼ Upground reservoirs exist primarily as drinking water storage but also are managed as a fishery and important sportfish species are stocked to provide fishing opportunities to anglers. In Northwest Ohio, these systems are common, and improving productivity of reservoirs as a fishery is an important goal for management agencies. One of the primary species is yellow perch (Perca flavescens) and among the upground reservoirs there are varying levels of success for yellow perch fisheries. A large scale investigation of these systems was undertaken in order to understand what is influencing the success of yellow perch in the systems. These variables were physical, chemical, or biological in nature, reflecting all the potential ways the environment and habitat could impact yellow perch in the reservoirs. The data was analyzed using classification and regression trees, along with principal components analysis (PCA), to determine which variables were important, by seeing which variables separate reservoirs with high abundances of yellow perch from those reservoirs with low abundances of yellow perch. Percentage of submerged macrophytes (to provide cover for juvenile yellow perch) was the most important variable. Higher levels of submerged macrophytes in general lead to higher abundances of yellow perch in the reservoirs. Existing reservoirs could be improved for yellow perch by adding structures that promote the growth of vegetation, and new reservoirs being constructed that may be targeted for yellow perch stocking could have aspects such as fish shelves added to create more vegetative cover for yellow perch.
Advisors/Committee Members: Miner, Jeffrey.
Subjects: Aquatic Sciences; Biology; Ecology; Freshwater Ecology; Limnology; Natural Resource Management
Keywords: yellow perch; reservoir; classification; littoral vegetation; submerged macrophytes; Sander; stocking; regression tree
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28.
Cupp, Audrey R.
PHOTOSYNTHETIC PICOPLANKTON AND BACTERIOPLANKTON IN THE CENTRAL BASIN OF LAKE ERIE DURING SEASONAL HYPOXIA.
Degree: MS, Biological Sciences, 2006, Bowling Green State University
► In Lake Erie’s central basin, a hypoxic region commonly termed the dead…
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▼ In Lake Erie’s central basin, a hypoxic region commonly termed the dead zone forms during late summer. Previous work has demonstrated an abundance of photosynthetic picocyanobacteria despite this lack of oxygen. High-throughput sequencing of over 400 cyanobacterial and eubacterial 16S rDNA amplicons has characterized some of the major members of the microbial community both during and prior to the dead zone formation. In July, the bacterial communities mainly consisted of two unique clusters of Gram-positive Actinobacteria, with a smaller percentage of Flexibacter-Cytophaga-Bacteroides , α, β, and γ Proteobacteria . Cyanobacteria in the form of photosynthetic picoplankton was found at 16.5 m in July, but was absent from the 20 m library. During hypoxia in August, a community shift was demonstrated with a decrease in the Flexibacter-Cytophaga-Bacteroides , an increase in number and diversity of cyanobacteria, and an increase in an α-Proteobacterial cluster. Diurnal oxygen production in the hypolimnion of Lake Erie was exhibited by in situ probes and showed actively photosynthetic picoplankton producing oxygen. Cyanobacterial 16S libraries showed an increase in diversity of photosynthetic picoplankton in August compared to July. The vast majority of clones similar to Synechococcus sp. MH301 were found in July with only a small percentage of clones from other groups. Conversely, during hypoxia, an increase of diversity was shown to exist. These differences in bacterial community members indicate the cycling of oxygen may influence the community structure in Lake Erie. Novel primers specific for the cpeB gene in phyoerythrin-rich (PE-rich) cyanobacteria were used to study diversity of potential marine-like forms, indicating a new way to phylogenetically study PE-rich cyanobacteria.
Advisors/Committee Members: Bullerjahn, George S.
Keywords: Lake Erie; microbial diversity; photosynthetic picoplankton; hypoxia; 16S rRNA
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29.
D'Elia, Tom V.
Isolation of Bacteria and Fungi from Lake Vostok Accretion Ice.
Degree: PhD, Biological Sciences, 2008, Bowling Green State University
► Lake Vostok, located below the 4000 m thick Antarctic Ice Sheet, is…
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▼ Lake Vostok, located below the 4000 m thick Antarctic Ice Sheet, is the largest subglacial lake in Antarctica. The lake water has not been sampled due to concerns of forward contamination. However, ice cores available from the Vostok 5G well of depths greater than 3538 m represent lake water that has accreted to the overhead glacier from various regions across Lake Vostok. Here, we report the characterization of bacteria and fungi from ten accretion ice sections (15,000 to 18,000 years old), and two deep glacial ice sections (1 to 2 million years old) from the Vostok, Antarctica 5G ice core. Fungi, as well as bacteria, were characterized by fluorescence microscopy, scanning electron microscopy, culturing, and sequence analyses of ribosomal DNA. A total of 703 bacteria and fungi were cultured from the accretion ice of subglacial Lake Vostok. Mean cell concentrations were from 2.3 to 12.3 cells per ml of ice meltwater, of which 5 to 84% were viable. These cell counts are substantially lower than previously reported values. A total of 54 unique ribosomal DNA sequences were determined and compared to recent taxa, of which 36 were fungi and 18 were bacteria. Fungi most closely related to Rhodotorula, Aureobasidium, Cryptococcus, Cladosporium and Penicillium, and bacteria related to Carnobacterium spp., Bacillus spp., Caulobacter and Micrococcus were identified based on sequence analysis from cultured isolates. These findings, plus tests for growth at low temperatures, indicate that Lake Vostok contains a mixture of heterotrophic psychrotolerant and psychrophilic species. The results revealed new genera of microorganisms not previously reported in Lake Vostok accretion ice, lower abundances of microorganisms, and demonstrated the necessity to use multiple methods to thoroughly characterize environmental ice.
Advisors/Committee Members: Rogers, Scott.
Subjects: Biology; Ecology; Microbiology; Molecular biology
Keywords: Lake Vostok; accretion ice; subglacial; Rhodotorula; glacier; ancient ice
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