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A Study Of Factors Affecting Scale Roughness In The Western Diamondback Rattlesnake (Crotalus Atrox), Amber Gail Skach

Biology Theses - Archive

Reptilian scales are very complex with patterns across their surface like a human fingerprint. These patterns are species specific, but there has been no way to quantify differences. A new technique using the confocal microscope allows measurement of the roughness of a surface. The roughness of the scales of Crotalus atrox were measured and compared with factors such as sex, age, clade, and various environmental variables to determine if this technique may be useful in determining species. The results found that the roughness of a scale decreased as the snake aged, and was significantly different between the two clades; the …

Geographic Variation In The Morphometrics Of Emydoide Blandingii, Maggie M. Camperlengo

Biology Theses - Archive

Morphometric measurements were taken from museum specimens Emydoidea blandingii. Samples were taken from Michigan, Wisconsin, Illinois, Iowa, Nebraska, New York and Minnesota as well as from Ontario, Canada. Populations of this species have become increasingly fragmented and isolated during the past century due primarily to the urbanization of North America which has included increased road related fatalities and habitat destruction. An examination of physical characteristics was conducted to determine if morphometric analysis could indicate differences among the various populations. Twenty-eight measurements were made and compared to detect physical distinctions between populations. Individuals were then classified geographically based on east (C), …

Metabolic And Phenotypic Characterization Of Aerobic Pcb Degrading Bacteria Isolated From Kalamazoo River Sediments, Brenton K. Lehmkuhl

Masters Theses

The Kalamazoo River is contaminated with polychlorinated biphenyls (PCBs) which are neurotoxins and suspected carcinogens. The goal of this study was to isolate, identify, and metabolically characterize PCB degrading strains of aerobic bacteria. Biphenyl enrichments resulted in the isolation of putative PCB degrading strains from different locations along the river. Based on 16S rRNA gene analysis the isolated strains were identified as belonging to the genera of Achromobacter, Acidovorax, Cellulosimicrobium, Paenibacillus, Pseudomonas, and Rhodococcus. These strains were screened for their PCB degrading ability and congener specificity. All of the isolated strains degraded PCBs via the 2,3-dioxygenase pathway. The range …

Identifying Individual Eurasian Otters (Lutra Lutra) Based On Measurements Of Their Footprints Standardization Of The Method And Its Potential For Censusing And Monitoring Wild Otter Populations, Jitka Vetrovcova

Biology Theses - Archive

A method for identifying individual Eurasian otters (Lutra lutra L.) from measurements of their footprints was first tested by performing experiments with captive animals. Digital photographs were taken of imprints in mud of all paws of 12 known individuals. Using customized software, 131 distance, angle, and proportion measurements were generated and subjected to discriminant and canonical analyses. The stepwise procedures of discrimination were the principal statistical analyses used. Analyzing each foot separately while using all available imprints yielded 86-93% correct classification and 59-77% Jacknife cross-validation. The efficiency of these analyses was not significantly affected by randomly reducing the number of …

Does An Exotic Invasive Grass Facilitate The Invasion Of A Woody Species Into Remnant Prairies?: A Study Of The Native, Prosopis Glandulosa And The Alien, Sorghum Halapense, Amie E. Treuer

Biology Theses - Archive

The native tree, Prosopis glandulosa, and the exotic grass, Sorghum halepense, have been invading native prairies in the Southwest U.S. since the 1800s. My objectives were to determine if S. halepense was driving shifts in the abiotic and biotic structure of a native prairie and in doing so facilitating the invasion of P. glandulosa. Both field and greenhouse experiments were established to address these objectives. The presence of S. halepense lowered light and increased soil N in the field relative to the native prairie. Plant species diversity and the number of woody species were higher in an invaded zone than …

Integration Without Unification: An Argument For Pluralism In The Biological Sciences, Sandra D. Mitchell, Michael R. Dietrich

Dartmouth Scholarship

In this article, we consider the tension between unification and pluralism in biological theory. We begin with a consideration of historical efforts to establish a unified understanding of evolution in the neo‐Darwinian synthesis. The fragmentation of the evolutionary synthesis by molecular evolution suggests the limitations of the general unificationist ideal for biology but not necessarily for integrating explanations. In the second half of this article, we defend a specific variety of pluralism that allows for the integration required for explanations of complex phenomena without unification on a large scale.

Evidence Of Influenza A Virus Rna In Siberian Lake Ice, Scott O. Rogers, Gang Zhang, Dany Shoham, David Gilchinsky, Sergei Davydov, John D. Castello

Biological Sciences Faculty Publications

Influenza A virus infects a large proportion of the human population annually, sometimes leading to the deaths of millions. The biotic cycles of infection are well characterized in the literature, including in studies of populations of humans, poultry, swine, and migratory waterfowl. However, there are few studies of abiotic reservoirs for this virus. Here, we report the preservation of influenza A virus genes in ice and water from high-latitude lakes that are visited by large numbers of migratory birds. The lakes are along the migratory flight paths of birds flying into Asia, North America, Europe, and Africa. The data suggest …

Frigida Like 2 Is A Functional Allele In Landsberg Erecta And Compensates For A Nonsense Allele Of Frigida Like 1, Michael Schläppi

Biological Sciences Faculty Research and Publications

The Landsberg erecta (Ler) accession of Arabidopsis (Arabidopsis thaliana) has a weak allele of the floral inhibitor FLOWERING LOCUS C (FLC). FLC-Ler is weakly up-regulated by the active San Feliu-2 (Sf2) allele of FRIGIDA (FRI-Sf2), resulting in a moderately late-flowering phenotype. By contrast, the Columbia (Col) allele of FLC is strongly up-regulated by FRI-Sf2, resulting in a very late-flowering phenotype. In Col, the FRI-related gene FRI LIKE 1 (FRL1) is required for FRI-mediated upregulation of FLC. It is shown here that in Ler …

Responses To Salinity Of Color Polymorphs In Two Populations Of The Sea Star, Pisaster Achraceus, Viren Johann Perumal

Loma Linda University Electronic Theses, Dissertations & Projects

Pisaster ochraceus was analyzed to determine if varying salinities, animal color, or location affect the physiology of these sea stars. The three responses analyzed were aerobic respiration, ammonia excretion, and self-righting. The tested variables included two different color morphs (orange and purple) of P. ochraceus, two different locations (open coast and inland straits) in Washington State, and three salinities (22, 30, and 40 psu).

Wet mass-specific oxygen consumption rates were not significantly affected by color, location, or salinity, and Dry mass-specific oxygen consumption rates showed no significant differences for main effects, but a three-way interaction was identified. Similarly, ammonia …

Conservation Taxonomy Of The Cuban Parrot: Morphological, Plumage And Flight Call Variation, M. Bryant J. Reynolds

Loma Linda University Electronic Theses, Dissertations & Projects

Conservation taxonomy, the study of organismal classification to clarify conservation priorities, seeks to define species and subspecies limits. Allopatric populations, such as those present on islands, pose special challenges to identifying taxonomic boundaries that can be be addressed using diagnostic criteria. Because some of the island populations of Cuban Parrot (Amazona leucocephala) are highly endangered, the five recognized subspecies need careful reevaluation. I measured 18 morphological and plumage characters from 188 museum specimens representing the six extant and one extirpated island populations. I also examined 11 spectrographic characters from the flight calls of 23 parrots representing all six …

A Quantitative Analysis Of Morphological Changes In Specific Laminae Of The Olfactory Bulb Of Adult Zebrafish Following Peripheral Sensory Deafferentation, Travis L. Devlin

Masters Theses

Permanent removal of the olfactory organ in adult zebrafish has been shown to result in a significant reduction in the total volume of the ipsilateral olfactory bulb. The overall objective of the current project was to investigate the hypothesis that contact between the axons of the olfactory sensory neurons and the olfactory bulb is necessary for the maintenance of the normal post-synaptic organization of the olfactory bulb by quantifying the morphological changes that take place within specific laminae of the olfactory bulb following peripheral deafferentation. Complete, unilateral ablation of the olfactory organ resulted in permanent deafferentation of the ipsilateral olfactory …

Karyotypes Of Eight Species Of Leptodactylus (Anura, Leptodactylidae) With A Description Of A New Karyotype For The Genus, Renata Cecília Amaro-Ghilardi, Gabriel Skuk, Rafael O. De Sá, Miguel Trefaut Rodrigues, Yatiyo Yonenaga-Yassuda

Biology Faculty Publications

Karyotypes of eight species of Leptodactylus (Anura, Leptodactylidae) with a description of a new karyotype for the genus. Eight species of the Neotropical genus Leptodactylus were karyologically studied: seven of them (L. gracilis, L. mystacinus, L. petersii, L. pustulatus, L. macrosternum, L. ocellatus, L. labyrinthicus) presented 2n=22 and L. silvanimbus showed a distinctive karyotype with 2n=24. Nucleolar organizer regions (Ag-NORs) were detected in two different pairs of chromosomes: pair 4 at the proximal region of the long arm of one individual of L. mystacinus from São Paulo state and of L. petersii; and …

The Distribution Of Lianas And Their Change In Abundance In Temperate Forests Over The Past 45 Years, Ronald A. Londre, Stefan A. Schnitzer

Biological Sciences Faculty Research and Publications

Lianas (woody vines) are an important and dynamic component of many forests throughout the world, and increases in CO₂, mean winter temperature, and forest fragmentation may promote their growth and proliferation in temperate forests. In this study, we used a 45‐year data set to test the hypothesis that lianas have increased in abundance and basal area in the interiors of 14 deciduous temperate forests in Wisconsin (USA) since 1959. We also censused woody plants along a gradient from the forest edge to the interior in seven of these forests to test the hypothesis that the abundance of lianas …

Genetic Resolution Of The Enigmatic Lesser Antillean Distribution Of The Frog Leptodactylus Validus (Anura, Leptodactylidae), Keneth Yanek, W. R. Heyer, Rafael O. De Sá

Biology Faculty Publications

Leptodactylus validus has an unusual distribution, inhabiting Trinidad, Tobago, and the Lesser Antilles, but not the mainland of South America. This distribution is inconsistent with other distribution patterns observed for these islands. Although slight variation in adult morphology has been observed among the different island populations of L. validus, call data suggest the presence of a single species. Calls of L. pallidirostris from Venezuela and Brazil suggested that this taxon might be conspecific with L. validus. Sequence data from the 12S and 16S mt rDNA genes indicate that L. validus represents a single species throughout its distribution and is conspecific …

Three Perspectives On Neutrality And Drift In Molecular Evolution, Michael Dietrich

Dartmouth Scholarship

This article offers three contrasting cases of the use of neutrality and drift in molecular evolution. In the first, neutrality is assumed as a simplest case for modeling. In the second and third, concepts of drift and neutrality are developed within the context of population genetics testing and the development and application of the molecular clock.

Outsiders As Innovators In The Life Sciences, Michael Dietrich

Dartmouth Scholarship

An introduction to the book Outsider Scientists: Routes to Innovation in Biology edited by Oren Harman and Michael Dietrich

Current And Historical Aquatic Food Webs Of The Middle Rio Grande, Nm, Melanie S. Edwards

Biology ETDs

The Rio Grande has been identified as one of the most endangered rivers in the United States by American Rivers. Biologically, the consequences of the massive anthropogenic alterations of this river have been substantial. The overall aim of this study was to characterize the ecological implications of these alterations in the aquatic food web of the middle Rio Grande (MRG) of New Mexico. Our approach was to analyze the stable isotope composition of current food web components and of historical museum preserved fish specimens. After determining that we could use stable isotope analyses of historical museum preserved fish specimens (chapter …

Linking Bacterioplankton Community Structures To Environmental State Variables And Phytoplankton Assemblages In Two South Carolina Salt Marsh Estuaries, Wes Johnson, Alan J. Lewitus, Madilyn Fletcher

Faculty Publications

Microorganisms are among the most important organisms to the ecology of salt marsh estuaries; however, fundamental questions regarding their distribution, environmental controls, and interactions with phytoplankton remain unanswered. We used denaturing gradient gel electrophoresis (DGGE) of bacterial rRNA genes and high performance liquid chromatography (HPLC) of phytoplankton photopigments to characterize planktonic communities from the Ashepoo, Combahee, and Edisto (ACE) Basin and North Inlet (NI) estuaries on the South Carolina coast, USA. Multivariate comparisons of the planktonic community profiles revealed that the 2 estuaries supported distinct bacterial communities. Furthermore, bacterial communities in both systems were partitioned into separate particle-associated (PA) and …

Investigation Of De Novo Cholesterol Synthetic Capacity In The Gonads Of Goldfish (Carassius Auratus) Exposed To The Phytosterol Beta-Sitosterol, Rainie L. Sharpe, Melissa Drolet, Deborah L. Maclatchy

Biology Faculty Publications

Total and intra-mitochondrial gonadal cholesterol concentrations are decreased in fish exposed to the phytoestrogen beta-sitosterol (beta-sit). The present study examined the potential for beta-sit to disrupt de novo cholesterol synthesis in the gonads of goldfish exposed to 200 microgram/g beta-sit and 10 microgram/g 17beta-estradiol (E2; estrogenic control) by intra-peritoneal Silastic® implants for 21 days. The de novo cholesterol synthetic capacity was estimated by incubating gonadal tissue with 14C-acetate for a period of 18 hours, followed by chloroform/methanol lipid extraction and thin layer chromatography (TLC) lipid separation. Lipid classes were confirmed using infrared spectroscopy. Plasma testosterone (T) and total cholesterol concentration …

Identification Of Micrornas And Other Small Rnas From The Adult Newt Eye, Evgeny Makarev, Jason R. Spence, Katia Del Rio-Tsonis, Panagiotis A. Tsonis

Biology Faculty Publications

MicroRNAs (miRNAs) are capable of controlling gene expression by targeting complimentary sequences in many mRNAs. Thus, a small number of miRNAs are capable of regulating expression of many different genes. miRNAs have been found in all animals from Drosophila to human and they are highly conserved. This work was undertaken in order to identify such RNAs in the newt eye.

The Lasthenia Californica Story: It Started With Flavonoids, Bruce A. Bohm, Nishanta Rajakaruna

Biological Sciences

Our laboratory's study of Lasthenia (Asteraceae) began with an examination of flavonoid profiles of all species of the genus. The finding of two distinct flavonoid races within the L. californica complex led us to investigate environmental factors that might have been responsible for selection of these particular forms. Data were gathered on soil chemistry, allozyme variation, breeding biology, the effect of water stress on plant growth, and ion uptake physiology. In conjunction with workers at other institutions, DNA studies were undertaken to determine evolutionary relationships between the two races. These studies led to the recognition that racial differences had arisen …

Influence Of Resource Pulses And Perennial Neighbors On The Establishment Of An Invasive Annual Grass In The Mojave Desert, Rebecca E. Drenovsky, J. J. James, M. A. Caird, R. L. Sheley

Biology

Invasion by exotic annual grasses is one of the most significant threats to arid ecosystems in the western USA. Current theories of invasibility predict plant communities become more susceptible to invasion whenever there is an increase in the amount of unused resources. The objective of this field study was to examine how resource pulses and temporal variation in resource demand by the native shrub vegetation influences establishment of the invasive annual grass Schismus arabicus. Water and nitrogen were applied as pulses in early spring, mid-spring, or continuously throughout the growing season to plots containing either Atriplex confertifolia or Atriplex …

The Effects Of Postfire Salvage Logging On Cavity-Nesting Birds, Richard L. Hutto, Susan M. Gallo

Biological Sciences Faculty Publications

We investigated the effects of postfire salvage logging on cavity-nesting birds by comparing nest densities and patterns of nest reuse over a three-year period in seven logged and eight unlogged patches of mixed-conifer forest in the Blackfoot-Clearwater Wildlife Management Area, Montana. We found 563 active nests of 18 cavity-nesting birds; all species were found nesting in the uncut burned forest plots, but only eight nested in the salvage-logged plots. All except one species nested at a higher density in the unlogged areas, and half of the species were significantly more abundant in the unlogged plots. Every timber-drilling and timber-gleaning species …

Oligomerization Of Hepatitis C Virus Core Protein Is Crucial For Interaction With The Cytoplasmic Domain Of E1 Envelope Protein, Kousuke Nakai, Toru Okamoto, Tomomi Kimura-Someya, Koji Ishii, Chang Kweng Lim, Hideki Tani, Eiko Matsuo, Takayuki Abe, Yoshio Mori, Tetsuro Suzuki, Tatsuo Miyamura, Jack H. Nunberg, Kohji Moriishi, Yoshiharu Matsuura

Biological Sciences Faculty Publications

Hepatitis C virus (HCV) contains two membrane-associated envelope glycoproteins, E1 and E2, which assemble as a heterodimer in the endoplasmic reticulum (ER). In this study, predictive algorithms and genetic analyses of deletion mutants and glycosylation site variants of the E1 glycoprotein were used to suggest that the glycoprotein can adopt two topologies in the ER membrane: the conventional type I membrane topology and a polytopic topology in which the protein spans the ER membrane twice with an intervening cytoplasmic loop (amino acid residues 288 to 360). We also demonstrate that the E1 glycoprotein is able to associate with the HCV …

Central Dysregulation Of The Hypothalamic-Pituitary-Adrenal Axis In Neuron-Specific Proopiomelanocortin-Deficient Mice, James L. Smart, Virgine Tolle, Veronica Otero-Corchon, Malcolm J. Low

Faculty Publications - Department of Biological & Molecular Science

No abstract provided.

A Quantitative Study Of Styles And Achenes Of Terminal And Basal Flowers Of Schoenoplectus Hallii (Cyperaceae), A Rare Plant Species Of Transient Wetland Habitats, Marian Smith, Sara Ammann, Nancy Parker, Paige Mettler-Cherry

Faculty Scholarship

Schoenoplectus hallii (A. Gray) S.G. Smith (Cyperaceae), a rare plant restricted to wetland habitats, is of conservation concern throughout its range. Taxonomy of the species recently has been clarified; however, quantitative descriptions of achene and flower morphology are incomplete and life history information is lacking. Because of its scarcity and the transient nature of populations, any large-scale study of the species will require the recovery of achenes from bulk soil samples and the identification and separation of the dimorphic achenes. The objectives of this study were to separate, identify and photograph the two achene types; to quantify the size and …

Ethyleneproduction As An Indicator Of Stress Conditions In Hydroponically-Grown Strawberries, Justin D. Hogan, Elizabeth E. Murray, Marcia Harrison-Pitaniello Phd

Biological Sciences Faculty Research

As a soilless system, hydroponics eliminates competing weeds and soil-born pests while conserving water and providing conditions that can be quickly altered to suit specific crops. However, stress-induced physiological conditions may arise within the system from factors such as mechanical injury, pests, or inconsistent nutrient flow rates that result in some plants receiving too much or too little water. Most abiotic stress conditions result in increased production of the plant hormone ethylene. High levels of ethylene inhibit growth, cause premature ripening, and induce the onset of senescence, potentially reducing the productivity of hydroponically-grown crops. In this study, we demonstrate that …

Target Dna Structure Plays A Critical Role In Rag Transposition, Jennifer E. Posey, Malgorzata J. Pytios, Richard R. Sinden, David B. Roth

Biomedical Engineering and Sciences Faculty Publications

Antigen receptor gene rearrangements are initiated by the RAG1/2 protein complex, which recognizes specific DNA sequences termed RSS (recombination signal sequences). The RAG recombinase can also catalyze transposition: integration of a DNA segment bounded by RSS into an unrelated DNA target. For reasons that remain poorly understood, such events occur readily in vitro, but are rarely detected in vivo. Previous work showed that non-B DNA structures, particularly hairpins, stimulate transposition. Here we show that the sequence of the four nucleotides at a hairpin tip modulates transposition efficiency over a surprisingly wide (>100-fold) range. Some hairpin targets stimulate extraordinarily efficient …

The Fat Cadherin Acts Through The Hippo Tumor-Suppressor Pathway To Regulate Tissue Size, Maria Willecke, Fisun Hamaratoglu, Madhuri Kango-Singh, Ryan Udan, Chiao-Lin Chen, Chunyao Tao, Xinwei Zhang, Georg Halder

Biology Faculty Publications

Background: The Hippo tumor-suppressor pathway has emerged as a key signaling pathway that controls tissue size in Drosophila. Merlin, the Drosophila homolog of the human Neurofibromatosis type-2 (NF2) tumor-suppressor gene, and the related protein Expanded are the most upstream components of the Hippo pathway identified so far. However, components acting upstream of Expanded and Merlin, such as transmembrane receptors, have not yet been identified.

Results: Here, we report that the protocadherin Fat acts as an upstream component in the Hippo pathway. Fat is a known tumor-suppressor gene in Drosophila, and fat mutants have severely overgrown imaginal discs. We …

Lobe And Serrate Are Required For Cell Survival During Early Eye Development In Drosophila, Amit Singh, Xiao Shi, Kwang-Wook Choi

Biology Faculty Publications

Organogenesis involves an initial surge of cell proliferation, leading to differentiation. This is followed by cell death in order to remove extra cells. During early development, there is little or no cell death. However, there is a lack of information concerning the genes required for survival during the early cell-proliferation phase. Here, we show that Lobe (L) and the Notch (N) ligand Serrate (Ser), which are both involved in ventral eye growth, are required for cell survival in the early eye disc. We observed that the loss-of-ventral-eye phenotype in L or Ser mutants is due to …