Biology Commons^™

A Cell Biology Laboratory Exercise To Study Sub-Cellular Organelles In Drosophila, Meghana Tare, Amit Singh

Biology Faculty Publications

The fast-changing scenario of undergraduate education puts emphasis on introducing students to hands-on techniques as part of their laboratory courses. In order to cater to large numbers of students and the time constraints involved with undergraduate level laboratory courses, there is a need for development of experiments that are cost effective and can be completed in a defined time frame. We have devised a laboratory exercise for teaching cell biology using the Drosophila melanogaster model. Drosophila can be reared in a short period of time in a cost effective manner. We used Drosophila tissue to study the sub-cellular organization of …

Spots Of Adult Male Red-Spotted Newts Are Redder And Brighter Than In Females: Evidence For A Role In Mate Selection?, Andrew K. Davis, Kristine L. Grayson

Biology Faculty Publications

As aquatic adults, eastern red-spotted newts (Notophthalmus v. viridescens) are generally green with two rows of dorsal spots, which vary in number between individuals and range in colour from orange to red. The function of these spots is unknown, but it is possible that they serve as sexual ornamentations and we examined this hypothesis by testing for sexual dimorphism in spot characteristics. We used an image analysis approach that has been used previously with this and other amphibian species to compare the number, size and colour – redness (hue score) and brightness – of spots in 100 male …

Transcriptional Response Of Mexican Axolotls To Ambystoma Tigrinum Virus (Atv) Infection, Jennifer D. Cotter, Andrew Storfer, Robert B. Page, Christopher K. Beachy, S. Randal Voss

Biology Faculty Publications

Background

Very little is known about the immunological responses of amphibians to pathogens that are causing global population declines. We used a custom microarray gene chip to characterize gene expression responses of axolotls (Ambystoma mexicanum) to an emerging viral pathogen, Ambystoma tigrinum virus (ATV).

Result

At 0, 24, 72, and 144 hours post-infection, spleen and lung samples were removed for estimation of host mRNA abundance and viral load. A total of 158 up-regulated and 105 down-regulated genes were identified across all time points using statistical and fold level criteria. The presumptive functions of these genes suggest a robust …

Transcriptional Response Of Mexican Axolotls To Ambystoma Tigrinum Virus (Atv) Infection, Jennifer D. Cotter, Andrew Storfer, Robert B. Page, Christopher K. Beachy, S. Randal Voss

Biology Faculty Publications

BACKGROUND: Very little is known about the immunological responses of amphibians to pathogens that are causing global population declines. We used a custom microarray gene chip to characterize gene expression responses of axolotls (Ambystoma mexicanum) to an emerging viral pathogen, Ambystoma tigrinum virus (ATV).

RESULT: At 0, 24, 72, and 144 hours post-infection, spleen and lung samples were removed for estimation of host mRNA abundance and viral load. A total of 158 up-regulated and 105 down-regulated genes were identified across all time points using statistical and fold level criteria. The presumptive functions of these genes suggest a robust innate immune …

Distinct Contributions Of Model Masp1 And Masp2 Like Peptides To The Mechanical Properties Of Synthetic Major Ampullate Silk Fibers As Revealed In Silico, Amanda E. Brooks, Shane R. Nelson, Justin A. Jones, Courtney Koenig, Michael Hinman, Michael Hinman, Shane Stricker, Randolph V. Lewis

Biology Faculty Publications

All characterized major ampullate silks from orb-web weaving spiders are composites of primarily two different proteins: MaSp1 and MaSp2. The conserved association of MaSp1 and MaSp2 in these spider species, the highly conserved amino acid motifs, and variable ratios of MaSp1 to MaSp2 demonstrate the importance of both MaSp1 and MaSp2 to the strength and elasticity of the fiber. Computer simulated mechanical tests predicted differing roles for MaSp1 and MaSp2 in the mechanical properties of the fibers. Recombinant MaSp1 and MaSp2 proteins were blended and spun into fibers mimicking the computer-simulated conditions. Mechanical testing verified the differing roles of MaSp1 …

Estimating Gene Signals From Noisy Microarray Images, Pinaki Sarder, Arye Nehorai, Paul H. Davis, Samuel L. Stanley Jr.

Biology Faculty Publications

In oligonucleotide microarray experiments, noise is a challenging problem, as biologists now are studying their organisms not in isolation but in the context of a natural environment. In low photomultiplier tube (PMT) voltage images, weak gene signals and their interactions with the background fluorescence noise are most problematic. In addition, nonspecific sequences bind to array spots intermittently causing inaccurate measurements. Conventional techniques cannot precisely separate the foreground and the background signals. In this paper, we propose analytically based estimation technique. We assume a priori spot-shape information using a circular outer periphery with an elliptical center hole. We assume Gaussian statistics …

An Improved String Composition Method For Sequence Comparison, Guoquing Lu, Shunpu Zhang, Xiang Fang

Biology Faculty Publications

Background: Historically, two categories of computational algorithms (alignment-based and alignment-free) have been applied to sequence comparison–one of the most fundamental issues in bioinformatics. Multiple sequence alignment, although dominantly used by biologists, possesses both fundamental as well as computational limitations. Consequently, alignment-free methods have been explored as important alternatives in estimating sequence similarity. Of the alignment-free methods, the string composition vector (CV) methods, which use the frequencies of nucleotide or amino acid strings to represent sequence information, show promising results in genome sequence comparison of prokaryotes. The existing CV-based methods, however, suffer certain statistical problems, thereby underestimating the amount of evolutionary …

A Bbp-Mud2p Heterodimer Mediates Branchpoint Recognition And Influences Splicing Substrate Abundance In Budding Yeast, Qiang Wang, Li Zhang, Bert C. Lynn, Brian C. Rymond

Biology Faculty Publications

The 3′ end of mammalian introns is marked by the branchpoint binding protein, SF1, and the U2AF65-U2AF35 heterodimer bound at an adjacent sequence. Baker's yeast has equivalent proteins, branchpoint binding protein (BBP) (SF1) and Mud2p (U2AF65), but lacks an obvious U2AF35 homolog, leaving open the question of whether another protein substitutes during spliceosome assembly. Gel filtration, affinity selection and mass spectrometry were used to show that rather than a U2AF65/U2AF35-like heterodimer, Mud2p forms a complex with BBP without a third (U2AF35-like) factor. Using mutants of MUD2 and BBP, we show that the BBP–Mud2p complex bridges partner-specific Prp39p, Mer1p, Clf1p …

Assessment Of A Non-Invasive High-Throughput Classifier For Behaviours Associated With Sleep And Wake In Mice, Kevin D. Donohue, Dharshan C. Medonza, Eli R. Crane, Bruce F. O'Hara

Biology Faculty Publications

This work presents a non-invasive high-throughput system for automatically detecting characteristic behaviours in mice over extended periods of time, useful for phenotyping experiments. The system classifies time intervals on the order of 2 to 4 seconds as corresponding to motions consistent with either active wake or inactivity associated with sleep. A single Polyvinylidine Difluoride (PVDF) sensor on the cage floor generates signals from motion resulting in pressure. This paper develops a linear classifier based on robust features extracted from normalized power spectra and autocorrelation functions, as well as novel features from the collapsed average (autocorrelation of complex spectrum), which characterize …

A New Reproductive Mode In The Genus Melanzophryniscus Gallardo, 1961 (Anura: Bufonidae) With Description Of A New Species From The State Of Paraná, Brazil, José A. Langone, Magno V. Segallo, Marcos Bornschein, Rafael O. De Sá

Biology Faculty Publications

A new species of bufonid toad of the genus Melanophryniscus is described from a mountaintop that is part of the Serra do Mar in the northeastern State of Paraná, Brazil. Melanophryniscus alipioi sp. nov. is distinguished from other known species by its uniformly dark brown dorsal color and a unique breeding site. The new species reproduces in bromeliads, a reproductive mode previously unknown for this genus. This species might be susceptible to current habitat lost.

A Songbird Forebrain Area Potentially Involved In Auditory Discrimination And Memory Formation, Raphael Pinaud, Thomas A. Terleph

Biology Faculty Publications

Songbirds rely on auditory processing of natural communication signals for a number of social behaviors, including mate selection, individual recognition and the rare behavior of vocal learning - the ability to learn vocalizations through imitation of an adult model, rather than by instinct. Like mammals, songbirds possess a set of interconnected ascending and descending auditory brain pathways that process acoustic information and that are presumably involved in the perceptual processing of vocal communication signals. Most auditory areas studied to date are located in the caudomedial forebrain of the songbird and include the thalamo-recipient field L (subfields L1, L2 and L3), …

Effect Of Thyroid Hormone Concentration On The Transcriptional Response Underlying Induced Metamorphosis In The Mexican Axolotl (Ambystoma), Robert B. Page, Stephen R. Voss, Amy K. Samuels, Jeramiah J. Smith, Srikrishna Putta, Christopher K. Beachy

Biology Faculty Publications

Background

Thyroid hormones (TH) induce gene expression programs that orchestrate amphibian metamorphosis. In contrast to anurans, many salamanders do not undergo metamorphosis in nature. However, they can be induced to undergo metamorphosis via exposure to thyroxine (T₄). We induced metamorphosis in juvenile Mexican axolotls (Ambystoma mexicanum) using 5 and 50 nM T₄, collected epidermal tissue from the head at four time points (Days 0, 2, 12, 28), and used microarray analysis to quantify mRNA abundances.

Results

Individuals reared in the higher T₄ concentration initiated morphological and transcriptional changes earlier and completed metamorphosis by …

A Novel Approach To Control Growth, Orientation, And Shape Of Human Osteoblasts, Jarema S. Czarnecki, Khalid Lafdi, Panagiotis A. Tsonis

Biology Faculty Publications

Carbon-based materials are considered to be promising materials as implants because of their unique mechanical and biocompatibility properties. The current paper investigates the use of carbon-based materials as a functional interface for tissue scaffolds and medical implants. Three basic parameters were explored such as graphene orientation, crystallinity and surface interaction. To explore the effect of the orientation, samples were made with and without a preferred carbon orientation. Conversely, the crystallinity was studied using graphitic and carbonaceous matrices. Fluorescent, confocal and environmental scanning microscopy was used to visualize cell response. The cell attachment, proliferation and elongation were prevalent on the unidirectional …

What Do Students Have To Say About Ecology And Evolution? Using Podcasting To Apply Integrative Biology Themes Across The Tree Of Life, Amy M. Treonis, Malcolm Hill, Theresa Dolson, Sue Mcginnis, Elizabeth Miles

Biology Faculty Publications

We describe a versatile podcasting assignment that requires students to (i) review primary and secondary literature relating to an assigned organism with the goal of identifying the main features of its ecology and evolution, (ii) prepare an enhanced podcast about their organism, and (iii) critique peer podcasts. The goal of this assignment is for each student to gain a fuller appreciation for and understanding of biological diversity. This assignment will enhance students' research, technology, and communication skills while reinforcing the main themes of integrative biology.

Antiretroviral Pre-Exposure Prophylaxis Prevents Vaginal Transmission Of Hiv-1 In Humanized Blt Mice, Paul W. Denton, Jacob D. Estes, Zhifeng Sun, Florence A. Othieno, Bangdong L. Wei, Anja K. Wege, Daniel A. Powell, Deborah A. Payne, Ashley T. Haase, J. Victor Garcia

Biology Faculty Publications

Background: Worldwide, vaginal transmission now accounts for more than half of newly acquired HIV-1 infections. Despite the urgency to develop and implement novel approaches capable of preventing HIV transmission, this process has been hindered by the lack of adequate small animal models for preclinical efficacy and safety testing. Given the importance of this route of transmission, we investigated the susceptibility of humanized mice to intravaginal HIV-1 infection.

Methods and Findings: We show that the female reproductive tract of humanized bone marrow–liver–thymus (BLT) mice is reconstituted with human CD4þ T and other relevant human cells, rendering these humanized mice …

Strain-Dependent Relationship Between Growth Rate And Hyphal Branching In Neurospora Crassa, Michael K. Watters, Erik Lindamood, Margaret Meunich, Ryan Vetor

Biology Faculty Publications

In a previous study of branch frequency in Neurospora crassa focused on the wild-type, no relationship between growth rate and the frequency of hyphal branching was observed. In subsequent experiments, it became clear that while this independence is valid for the wild type and most mutant strains, it fails to hold for a subset of morphological mutants. This study distinguishes a subset of Neurospora morphological mutants for their morphological response to altered growth rate. Growth rates are altered using two different methods: reduced temperature and nutrient-deficient media. This should assure that the observed effect is not due to simple conditional …

Methods For Detection Of Matrix Metalloproteinases As Biomarkers In Cardiovascular Disease, Viorica Lopez-Avila, Juliet Spencer

Biology Faculty Publications

Matrix metalloproteinases (MMPs) are a family of zinc-dependent proteolytic enzymes that degrade extracellular matrix (ECM) components like collagen, fibronectin, and laminin. While this activity is important for normal development, morphogenesis, and wound healing, deregulation of MMP activity has been implicated in a number of cardiovascular diseases, including congenital heart defects, atherosclerosis, myocardial infarction, and congestive heart failure. MMPs are good potential diagnostic indicators of cardiovascular disease, but current detection methods are time consuming and quite laborious. This review will discuss MMP biology, current methods for detection of MMPs from patient samples, and potential new developments in multiplexed analysis of MMPs.

New Genus And Species Of Aporocotylidae (Digenea) From A Basal Actinopterygian, The American Paddlefish, Polyodon Spathula, (Acipenseriformes: Polyodontidae) From The Mississippi Delta, Stephen A. Bullard, Scott D. Snyder, Kirsten Jensen, Robin M. Overstreet

Biology Faculty Publications

Acipensericola petersoni n. gen., n. sp. (Digenea: Aporocotylidae) infects the heart of the American paddlefish Polyodon spathula (Walbaum, 1792) in the Mississippi Delta. It has robust, spike-like body spines arranged in ventrolateral transverse rows; a bowl-shaped anterior sucker centered on the mouth and having minute spines on the inner anteroventral surface only; a pharynx; an inverse U-shaped ceca extending to near the posterior body end; intercecal testes comprising a pre-ovarian testicular column plus a single testis posteriorly; an extensively lobed ovary located medially and immediately posterior to the testicular column; a spherical ootype that is intercecal and post-ovarian; a Laurer’s …

Strong Genetic Differentiation Among Neighboring Populations Of A Locally Endemic Primrose, L. Bjerregaard, Paul G. Wolf

Biology Faculty Publications

Maguire primrose is a locally endemic plant of northern Utah, USA, with a total known range of less than 20 km2. A previous study found evidence for strong differentiation among local populations at 4 allozyme loci. Here we reexamined populations using 165 AFLP loci and found further evidence of unusually strong genetic structure. We also found an apparently fixed nucleotide difference between populations for a noncoding region of chloroplast DNA, mirroring the patterns seen for AFLP loci. Furthermore, we tested the hypothesis that the current population structure is the result of breeding barriers between plants from different populations. We made …

Are Rivers Just Bigstreams? Using A Pulse Method To Measure Nitrogen Demand In A Large River, J. L. Tank, E. J. Rosi-Marshall, Michelle A. Baker, R. O. Hall Jr.

Biology Faculty Publications

Given recent focus on large rivers as conduits for excess nutrients to coastal zones, their role in processing and retaining nutrients has been overlooked and understudied. Empirical measurements of nutrient uptake in large rivers are lacking, despite a substantial body of knowledge on nutrient transport and removal in smaller streams. Researchers interested in nutrient transport by rivers (discharge >10000 L/s) are left to extrapolate riverine nutrient demand using a modeling framework or a mass balance approach. To begin to fill this knowledge gap, we present data using a pulse method to measure inorganic nitrogen. (N) transport and removal in the …

On Estimating The Exponent Of Power-Law Frequency Distributions, Ethan P. White, B. J. Enquist, J. L. Green

Biology Faculty Publications

Power-law frequency distributions characterize a wide array of natural phenomena. In ecology, biology, and many physical and social sciences, the exponents of these power-laws are estimated to draw inference about the processes underlying the phenomenon, to test theoretical models, and to scale up from local observations to global patterns. Therefore, it is essential that these exponents be estimated accurately. Unfortunately, the binning-based methods traditionally utilized in ecology and other disciplines perform quite poorly. Here we discuss more sophisticated methods for fitting these exponents based on cumulative distribution functions and maximum likelihood estimation. We illustrate their superior performance at estimating known …

Zero-Sum, The Niche,And Metacommunities: Long-Term Dynamics Of Community Assembly, S.K. Morgan Ernest, J. H. Brown, K. M. Thibault, Ethan P. White, J. R. Goheen

Biology Faculty Publications

Recent models of community assembly, structure, and dynamics have incorporated, to varying degrees, three mechanistic processes: resource limitation and interspecific competition, niche requirements of species, and exchanges between a local community and a regional species pool. Synthesizing 30 years of data from an intensively studied desert rodent community, we show that all of these processes, separately and in combination, have influenced the structural organization of this community and affected its dynamical response to both natural environmental changes and experimental perturbations. In addition, our analyses suggest that zero-sum constraints, niche differences, and metacommunity processes are inextricably linked in the ways that …

Leptodactylus Cunicularius Sazima And Bokermann Rabbit-Burrow Frog, W. R. Heyer, M. M. Heyer, Rafael O. De Sá

Biology Faculty Publications

Adult Leptodactylus cunicularius are moderately small. The head is longer than wide and the hind limbs are long (Table 1; Heyer and Thompson 2000 provided definitions of adult size and leg length categories for Leptodactylus). Male vocal sacs are internal, not externally expanded. The snout is protruding, not sexually dimorphic. Male forearms are not hypertrophied and males lack asperities on the thumbs and chest. The dorsum is variegated with small, often confluent, spots and blotches. There is a very thin interrupted mid-dorsal light stripe (pinstripe). Usually, there is a noticeable light, irregular, elongate, mid-dorsal blotch in the scapular region. …

Is The Amphibian Tree Of Life Really Fatally Flawed?, Darrel R. Frost, Taran Grant, Julian Faivovich, Raoul H. Bain, Alexander Haas, Celio F.B. Haddad, Rafael O. De Sá, Et Al.

Biology Faculty Publications

Wiens (2007, Q. Rev. Biol. 82, 55–56) recently published a severe critique of Frost et al.'s (2006, Bull. Am. Mus. Nat. Hist. 297, 1–370) monographic study of amphibian systematics, concluding that it is “a disaster” and recommending that readers “simply ignore this study”. Beyond the hyperbole, Wiens raised four general objections that he regarded as “fatal flaws”: (1) the sampling design was insufficient for the generic changes made and taxonomic changes were made without including all type species; (2) the nuclear gene most commonly used in amphibian phylogenetics, RAG-1, was not included, nor were the morphological characters that had justified …

Assessment Of Synaptic Function During Short-Term Facilitation In Motor Nerve Terminals In The Crayfish, Mohati Desai-Shah, Kert Viele, G. Sparks, J. Nadolski, B. Hayden, V. K. Srinivasan, Robin L. Cooper

Biology Faculty Publications

An enhanced buildup of [Ca²⁺]i occurs during short-term facilitation (STF) at the crayfish neuromuscular junction (NMJ). As a model system, this NMJ allows discrete postsynaptic quantal events to be counted and characterized in relation to STF. Providing 10 pulses, at 20 and 40Hz, we monitored postsynaptic quantal events over a discrete region of a nerve terminal with a focal macropatch electrode. Characteristics of quantal events were clustered into groups by peak amplitude and time to the peak amplitude. Since the synapses at this NMJ have varied spacing of active zones, number of active zones and synaptic size, the …

Presynaptic Depression In Phasic Motor Nerve Terminals And Influence Of 5-Ht On Vesicle Dynamics, A. F. M. Johnstone, S. S. Kellie, Robin L. Cooper

Biology Faculty Publications

Synaptic depression that is induced by electrical stimulation of the glutamatergic neuromuscular junction (NMJ) of the crayfish can be offset by recruitment of vesicles from a presynaptic reserve pool. This recruitment occurs following treatment of the NMJ with serotonin (5-HT), which results in a delay in the onset of synaptic depression induced by high frequency stimulation. The results of this study demonstrate that the releasable vesicles are insufficiently replenished during high frequency stimulation and that the readily releasable pool of vesicles (RRP) can be enhanced by the reserve pool (RP) in the presence of 5-HT. Anatomical visualization of vesicular pools …

Optimal Data Partitioning And A Test Case For Ray-Finned Fishes (Actinopterygii) Based On Ten Nuclear Loci, Chenhong Li, Guoqing Lu, Guillermo Orti

Biology Faculty Publications

Data partitioning, the combined phylogenetic analysis of homogeneous blocks of data, is a common strategy used to accommodate heterogeneities in complex multilocus data sets. Variation in evolutionary rates and substitution patterns among sites are typically addressed by partitioning data by gene, codon position, or both. Excessive partitioning of the data, however, could lead to overparameterization; therefore, it seems critical to define the minimum numbers of partitions necessary to improve the overall fit of the model. We propose a new method, based on cluster analysis, to find an optimal partitioning strategy for multilocus protein-coding data sets. A heuristic exploration of alternative …

Chihuahuan Desertkangaroo Rats: Nonlinear Effects Of Population Dynamics, Competition, And Rainfall, M. Lima, S.K. Morgan Ernest, J. H. Brown, A. Belgrano, N. C. Stenseth

Biology Faculty Publications

Using long-term data on two kangaroo rats in the Chihuahuan Desert of North America, we fitted logistic models including the exogenous effects of seasonal rainfall patterns. Our aim was to test the effects of intraspecific interactions and seasonal rainfall in explaining and predicting the numerical fluctuations of these two kangaroo rats. We found that logistic models fit both data sets quite well; Dipodomys merriami showed lower maximum per capita growth rates than Dipodomys ordii, and in both cases logistic models were nonlinear. Summer rainfall appears to be the most important exogenous effect for both rodent populations; models including this variable …

On The Relationship Between Mass And Diameter Distributions In Tree Communities, J. C. Stegen, Ethan P. White

Biology Faculty Publications

It has been suggested that frequency distributions of individual tree masses in natural stands are characterized by power-law distributions with exponents near -3/4, and that therefore tree communities exhibit energetic equivalence among size classes. Because the mass of trees is not measured directly, but estimated from diameter, this supposition is based on the fact that the observed distribution of tree diameters is approximately characterized by a power-law with an exponent -2. Here we show that diameter distributions of this form are not equivalent to mass distributions with exponents of -3/4, but actually to mass distributions with exponents of -11/8. We …

Functional Gene Losses Occur With Minimal Size Reduction In The Plastid Genome Of The Parasitic Liverwort Aneura Mirabilis, N. J. Wickett, Y. Zhang, S. K. Hansen, J. M. Roper, J. V. Kuehl, S. A. Plock, B. Goffinet, Paul G. Wolf, C. W. Depamphilis, Jeffrey L. Boore

Biology Faculty Publications

Aneura mirabilis is a parasitic liverwort that exploits an existing mycorrhizal association between a basidiomycete and a host tree. This unusual liverwort is the only known parasitic seedless land plant with a completely nonphotosynthetic life history. The complete plastid genome of A. mirabilis was sequenced to examine the effect of its nonphotosynthetic life history on plastid genome content. Using a partial genomic fosmid library approach, the genome was sequenced and shown to be 108,007 bp with a structure typical of green plant plastids. Comparisons were made with the plastid genome of Marchantia polymorpha, the only other liverwort plastid sequence available. …