Biology Commons^™

Variable Effect Of Co-Infection On The Hiv Infectivity: Within-Host Dynamics And Epidemiological Significance, Diego F. Cuadros, Gisela García-Ramos

Biology Faculty Publications

BACKGROUND: Recent studies have implicated viral characteristics in accounting for the variation in the HIV set-point viral load (spVL) observed among individuals. These studies have suggested that the spVL might be a heritable factor. The spVL, however, is not in an absolute equilibrium state; it is frequently perturbed by immune activations generated by co-infections, resulting in a significant amplification of the HIV viral load (VL). Here, we postulated that if the HIV replication capacity were an important determinant of the spVL, it would also determine the effect of co-infection on the VL. Then, we hypothesized that viral factors contribute to …

Targeted Disruption Of Toxoplasma Gondii Serine Protease Inhibitor 1 Increases Bradyzoite Cyst Formation In Vitro And Parasite Tissue Burden In Mice, Viviana Pszenny, Paul H. Davis, Xing W. Zhou, Christopher A. Hunter, Vern B. Carruthers, David S. Roos

Biology Faculty Publications

As an intracellular protozoan parasite, Toxoplasma gondii is likely to exploit proteases for host cell invasion, acquisition of nutrients, avoidance of host protective responses, escape from the parasitophorous vacuole, differentiation, and other activities. T. gondii serine protease inhibitor 1 (TgPI1) is the most abundantly expressed protease inhibitor in parasite tachyzoites. We show here that alternative splicing produces two TgPI1 isoforms, both of which are secreted via dense granules into the parasitophorous vacuole shortly after invasion, become progressively more abundant over the course of the infectious cycle, and can be detected in the infected host cell cytoplasm. To …

The Bird Of Time: Cognition And The Avian Biological Clock, Vincent M. Cassone, David F. Westneat

Biology Faculty Publications

Avian behavior and physiology are embedded in time at many levels of biological organization. Biological clock function in birds is critical for sleep/wake cycles, but may also regulate the acquisition of place memory, learning of song from tutors, social integration, and time-compensated navigation. This relationship has two major implications. First, mechanisms of the circadian clock should be linked in some way to the mechanisms of all these behaviors. How is not yet clear, and evidence that the central clock has effects is piecemeal. Second, selection acting on characters that are linked to the circadian clock should influence aspects of the …

Implication Of The Mir-184 And Mir-204 Competitive Rna Network In Control Of Mouse Secondary Cataract, Andrea Hoffmann, Yusen Huang, Rinako Suetsugu-Maki, Carol S. Ringelberg, Craig R. Tomlinson, Katia Del Rio-Tsonis, Panagiotis A. Tsonis

Biology Faculty Publications

The high recurrence rate of secondary cataract (SC) is caused by the intrinsic differentiation activity of residual lens epithelial cells after extra-capsular lens removal. The objective of this study was to identify changes in the microRNA (miRNA) expression profile during mouse SC formation and to selectively manipulate miRNA expression for potential therapeutic intervention. To model SC, mouse cataract surgery was performed and temporal changes in the miRNA expression pattern were determined by microarray analysis. To study the potential SC counterregulative effect of miRNAs, a lens capsular bag in vitro model was used. Within the first 3 wks after cataract surgery, …

Environmentally Realistic Exposure To The Herbicide Atrazine Alters Some Sexually Selected Traits In Male Guppies, Kausalya Shenoy

Biology Faculty Publications

Male mating signals, including ornaments and courtship displays, and other sexually selected traits, like male-male aggression, are largely controlled by sex hormones. Environmental pollutants, notably endocrine disrupting compounds, can interfere with the proper functioning of hormones, thereby impacting the expression of hormonally regulated traits. Atrazine, one of the most widely used herbicides, can alter sex hormone levels in exposed animals. I tested the effects of environmentally relevant atrazine exposures on mating signals and behaviors in male guppies, a sexually dimorphic freshwater fish. Prolonged atrazine exposure reduced the expression of two honest signals: the area of orange spots (ornaments) and the …

High Altitude Diving In River Otters: Coping With Combined Hypoxic Stresses, Jamie R. Crait, Henry D. Prange, Noah A. Marshall, Henry J. Harlow, Clark Cotton, Merav Ben-David

Biology Faculty Publications

River otters (Lontra canadensis) are highly active, semi-aquatic mammals indigenous to a range of elevations and represent an appropriate model for assessing the physiological responses to diving at altitude. In this study, we performed blood gas analyses and compared blood chemistry of river otters from a high-elevation (2357 m) population at Yellowstone Lake with a sea-level population along the Pacific coast. Comparisons of oxygen dissociation curves (ODC) revealed no significant difference in hemoglobin-oxygen (Hb-O₂) binding affinity between the two populations - potentially because of demands for tissue oxygenation. Instead, high-elevation otters had greater Hb concentrations (18.7 …

Tumor Suppression By Cell Competition Through Regulation Of The Hippo Pathway, Chiao-Lin Chen, Molly C. Schroeder, Madhuri Kango-Singh, Chunyao Tao, Georg Halder

Biology Faculty Publications

Homeostatic mechanisms can eliminate abnormal cells to prevent diseases such as cancer. However, the underlying mechanisms of this surveillance are poorly understood. Here we investigated how clones of cells mutant for the neoplastic tumor suppressor gene scribble (scrib) are eliminated from Drosophila imaginal discs. When all cells in imaginal discs are mutant for scrib, they hyperactivate the Hippo pathway effector Yorkie (Yki), which drives growth of the discs into large neoplastic masses. Strikingly, when discs also contain normal cells, the scrib− cells do not overproliferate and eventually undergo apoptosis through JNK-dependent mechanisms. However, induction of apoptosis does …

Increased Variability Of Microbial Communities In Restored Salt Marshes Nearly 30 Years After Tidal Flow Restoration, Anne E. Bernhard, David Marshall, Lazaros Yiannos

Biology Faculty Publications

We analyzed microbial diversity and community composition from four salt marsh sites that were impounded for 40–50 years and subsequently restored and four unimpounded sites in southeastern Connecticut over one growing season. Community composition and diversity were assessed by terminal restriction fragment length polymorphism (TRFLP) and sequence analysis of 16S ribosomal RNA (rRNA) genes. Our results indicated diverse communities, with sequences representing 14 different bacterial divisions. Proteobacteria, Bacteroidetes, and Planctomycetes dominated clone libraries from both restored and unimpounded sites. Multivariate analysis of the TRFLP data suggest significant site, sample date, and restoration status effects, but the exact causes of these …

Nef Functions In Blt Mice To Enhance Hiv-1 Replication And Deplete Cd4+Cd8+ Thymocytes, Wei Zou, Paul W. Denton, Richard L. Watkins, John F. Krisko, Tomonori Nochi, John L. Foster, J. Victor Garcia

Biology Faculty Publications

Background: The outcome of untreated HIV-1 infection is progression to AIDS and death in nearly all cases. Some important exceptions are the small number of patients infected with HIV-1 deleted for the accessory gene, nef. With these infections, disease progression is entirely suppressed or greatly delayed. Whether Nef is critical for high levels of replication or is directly cytotoxic remains controversial. The major problem in determining the role of Nef in HIV/AIDS has been the lack of tractable in vivo models where Nef’s complex pathogenic phenotype can be recapitulated.

Results: Intravenous inoculation (3000 to 600,000 TCIU) of BLT …

Receptor Chimeras Demonstrate That The C-Terminal Domain Of The Human Cytomegalovirus Us27 Gene Product Is Necessary And Sufficient For Intracellular Receptor Localization, Lance K. Stapleton, Kathleen L. Arnolds, Angela P. Lares, Tori M. Devito, Juliet V. Spencer

Biology Faculty Publications

Background

Human cytomegalovirus (HCMV) is ubiquitous in the population but generally causes only mild or asymptomatic infection except in immune suppressed individuals. HCMV employs numerous strategies for manipulating infected cells, including mimicry of G-protein coupled receptors (GPCRs). The HCMV US27 gene product is a putative GPCR, yet no ligand or signaling has been identified for this receptor. In the present study, immunofluorescence microscopy was used to examine the cellular distribution of wild type US27, as well as US27 deletion mutants and chimeric receptors.

Results

In transiently transfected cells, wild type US27 was found primarily in intracellular compartments, in striking contrast …

Toxic Effects Of Copper, Cadmium, And Methoxychlor Shown By Neutral Red Retention Assay In Two Species Of Freshwater Molluscs, Nikolett Molnar, Peter Fong

Biology Faculty Publications

We used neutral red retention assay in lysosomes of digestive gland cells as an indicator for stress effects by the environmental contaminants Cu, Cd, and the pesticide methoxychlor in two freshwater molluscs, the unionid mussel, Elliptio complanata (Lightfoot) and the ramshorn snail Helisoma trivolvis (Say). Mussels and snails were exposed for 7 and 14 days to Cu and Cd each at nominal concentrations of 2.5 μg/L, 5.0 μg/L, and 10.0 μg/L, and to methoxychlor concentrations of 1.0 μg/L, 10.0μg/L, and 100.0 μg/L. Both mussels and snails exposed to Cu showed a significant increase in the percent of destabilized lysosomes compared …

Conserving Our Cultural Heritage: The Role Of Fungi In Biodeterioration, Hanna Szczepanowska, A. R. Cavaliere

Biology Faculty Publications

The objects of cultural heritage are composed of varied materials which can be affected by diverse microbial communities. The study of these complex and heterogeneous assemblies of materials and microorganisms require an inter- and multi-disciplinary approach. Development of a strategy towards prevention, mitigation of biodeterioration and removal of microorganisms, especially fungi begins with the understanding of the materials' fabric, assessment of causes behind the biodeterioration, and the context in which it occurs.

Three aspects of biodeterioration of cultural heritage are discussed: 1) the multitude of bio-agents' on cultural heritage materials, 2) fungal interaction with substrates, and 3) prevention and conservation …

Strong Self-Limitation Promotes The Persistence Ofrare Species, G. M. Yenni, P. B. Adler, S.K. Morgan Ernest

Biology Faculty Publications

Theory has recognized a combination of niche and neutral processes each contributing, with varying importance, to species coexistence. However, long-term persistence of rare species has been difficult to produce in trait-based models of coexistence that incorporate stochastic dynamics, raising questions about how rare species persist despite such variability. Following recent evidence that rare species may experience significantly different population dynamics than dominant species, we use a plant community model to simulate the effect of disproportionately strong negative frequency dependence on the long-term persistence of the rare species in a simulated community. This strong self-limitation produces long persistence times for the …

Notes On Notonectidae (Hemiptera: Heteroptera) From Southeastern Asia, Mostly From Brunei And The Philippines, Hendrik Freitag, Herbert Zettel, David J.W Lane, Clister V. Pangantihon

Biology Faculty Publications

Updated distribution data are presented for the following species of Notonectidae (Heteroptera) in southeastern Asia: Anisops breddini Kirkaldy, 1901, A. kuroiwae Matsumura, 1915, A. nasutus Fieber, 1851, A. nigrolineatus Lundblad, 1933, A. occipitalis Breddin, 1905, A. rhomboides Nieser & Chen, 1999, A. stali Kirkaldy, 1904, Aphelonecta philippina Zettel, 1995, Enithares bakeri Brooks, 1948, E. freyi Brooks, 1948, E. intha Paiva, 1918, E. mandalayensis Distant, 1910, E. martini martini Kirkaldy, 1898, E. quadrispinosa Lansbury, 1967, E. sinica (Stål, 1854), E. subparallela Lansbury, 1968, E. uncata Lundblad, 1933, E. cf. vicintricata Lansbury, 1968, and Nychia sappho Kirkaldy, 1901. There are six fi …

Digital Microscopic Imaging Of Important Taxonomic Characters Of Philippine Hydraena (Hydraenopsis) Species, Hendrik Freitag

Biology Faculty Publications

Biodiversity surveys have revealed several new aquatic beetle species of minute size (0.9 mm to 1.8 mm body length). Following modern standards of morphological taxonomy, internal and external microstructures such as aedeagus, ovipositor, spermatheca, gonocoxite as well as the distribution pattern and shape of certain hair structures were used to illustrate the distinguishing characters of new species. As even the smallest diaphragm opening of light microscopes fails to retrieve images of sufficient depth of the field, light microscope images under ZEISS Primo Vert inverted microscope, equipped with ZEISS LD Plan-ACHROMAT 20X objective lens, and an OLYMPUS SZ 61 stereomicroscope, were …

Leptodactylus Pentadactylus, Miriam M. Heyer, W. R. Heyer, Rafael O. De Sá

Biology Faculty Publications

Adult Leptodactylus pentadactylus (Figure 1) are large, the head is about as wide as long, and the hind limbs are moderately long (Table 1; Heyer and Thompson [2000] provided definitions of adult size and leg length categories for Leptodactylus). Male vocal sacs are not visible externally or are moderately expanded as a single sac. Sexually active males usually do not have hypertrophied forearms (the largest male examined, 195 mm SVL, has very weakly hypertrophied forearms), only the largest males have a single small to moderate size black spine on each thumb. No males have chest spines. Dorsolateral folds are …

Toxoplasma On The Brain: Understanding Host-Pathogen Interactions In Chronic Cns Infection, Sushrut Kamerkar, Paul H. Davis

Biology Faculty Publications

Toxoplasma gondii is a prevalent obligate intracellular parasite which chronically infects more than a third of the world’s population. Key to parasite prevalence is its ability to form chronic and nonimmunogenic bradyzoite cysts, which typically form in the brain and muscle cells of infected mammals, including humans. While acute clinical infection typically involves neurological and/or ocular damage, chronic infection has been more recently linked to behavioral changes. Establishment and maintenance of chronic infection involves a balance between the host immunity and parasite evasion of the immune response. Here, we outline the known cellular interplay between Toxoplasma gondii and cells of …

Phylomarker—A Tool For Mining Phylogenetic Markers Through Genome Comparison: Application Of The Mouse Lemur (Genus Microcebus) Phylogeny, Runhua Lei, Thaine W. Rowley, Lifeng Zhu, Carolyn A. Bailey, Shannon E. Engberg, Mindy L. Wood, Mary C. Christman, George H. Perry, Edward E. Louis Jr., Guoqing Lu

Biology Faculty Publications

Molecular phylogeny is a fundamental tool to understanding the evolution of all life forms. One common issue faced by molecular phylogeny is the lack of sufficient molecular markers. Here, we present PhyloMarker, a phylogenomic tool designed to find nuclear gene markers for the inference of phylogeny through multiple genome comparison. Around 800 candidate markers were identified by PhyloMarker through comparison of partial genomes of Microcebus and Otolemur. In experimental tests of 20 randomly selected markers, nine markers were successfully amplified by PCR and directly sequenced in all 17 nominal Microcebus species. Phylogenetic analyses of the sequence data obtained for 17 …

The Cell Division Gene Ftsz2 Of Sinorhizobium Meliloti Is Expressed At High Levels In Host Plant Medicago Truncatula Nodules In The Absence Of Sini, Muhamad Ali K. Shakhatreh, Jayne B. Robinson

Biology Faculty Publications

In this study, we investigated the role of quorum sensing (QS) in expression of the Sinorhizobium meliloti cell division gene ftsZ2 in free-living cells and within nodules of its host plant, Medicago truncatula. Using a ftsZ2 promoter reporter fusion, we were able to track the expression of this gene in wild-type S. meliloti cells and QS mutant backgrounds in planta. Our findings revealed that expression of ftsZ2 in free-living cells was changed or reduced in sinI mutant cells compared with wild-type cells while expression in planta was substantially higher in the absence of sinI. The results further clarify the involvement …

Patterns Of Gene Expression In Microarrays And Expressed Sequence Tags From Normal And Cataractous Lenses, Konstantinos Sousounis, Panagiotis A. Tsonis

Biology Faculty Publications

In this contribution, we have examined the patterns of gene expression in normal and cataractous lenses as presented in five different papers using microarrays and expressed sequence tags. The purpose was to evaluate unique and common patterns of gene expression during development, aging and cataracts.

Lens Regeneration In Axolotl: New Evidence Of Developmental Plasticity, Rinako Suetsugu-Maki, Nobuyasu Maki, Saulius Sumanas, Jie Zhu, Katia Del Rio-Tsonis, Panagiotis A. Tsonis

Biology Faculty Publications

Background: Among vertebrates lens regeneration is most pronounced in newts, which have the ability to regenerate the entire lens throughout their lives. Regeneration occurs from the dorsal iris by transdifferentiation of the pigment epithelial cells. Interestingly, the ventral iris never contributes to regeneration. Frogs have limited lens regeneration capacity elicited from the cornea during pre-metamorphic stages. The axolotl is another salamander which, like the newt, regenerates its limbs or its tail with the spinal cord, but up until now all reports have shown that it does not regenerate the lens.

Conservation Of The Three-Dimensional Structure In Non-Homologous Or Unrelated Proteins, Konstantinos Sousounis, Carl E. Haney, Jin Cao, Bharath Sunchu, Panagiotis A. Tsonis

Biology Faculty Publications

In this review, we examine examples of conservation of protein structural motifs in unrelated or non-homologous proteins. For this, we have selected three DNA-binding motifs: the histone fold, the helix-turn-helix motif, and the zinc finger, as well as the globin-like fold. We show that indeed similar structures exist in unrelated proteins, strengthening the concept that three-dimensional conservation might be more important than the primary amino acid sequence.

Detection Of Mycobacterium Ulcerans In The Environment Predicts Prevalence Of Buruli Ulcer In Benin, Heather R. Williamson, Mark Eric Benbow, Lindsay P. Cambell, Christian R. Johnson, Ghislain Sopoh, Yves Barogui, Richard W. Merritt, Pamela L. C. Small

Biology Faculty Publications

Background: Mycobacterium ulcerans is the causative agent of Buruli ulcer (BU), a destructive skin disease found predominantly in sub-Saharan Africa and south-eastern Australia. The precise mode(s) of transmission and environmental reservoir(s) remain unknown, but several studies have explored the role of aquatic invertebrate species. The purpose of this study was to investigate the environmental distribution of M. ulcerans in south-eastern Australia.

An Improved Competitive Inhibition Enzymatic Immunoassay Method For Tetrodotoxin Quantification, James P. Strange, Becky L. Williams, Susannah S. French

Biology Faculty Publications

Quantifying tetrodotoxin (TTX) has been a challenge in both ecological and medical research due to the cost, time and training required of most quantification techniques. Here we present a modified Competitive Inhibition Enzymatic Immunoassay for the quantification of TTX, and to aid researchers in the optimization of this technique for widespread use with a high degree of accuracy and repeatability.

Improved Ex Vivo Method For Microbiocidal Activity Across Vertebrate Species, Susannah S. French, Lorin A. Neuman-Lee

Biology Faculty Publications

The field of ecoimmunology is currently undergoing rapid expansion, whereby biologists from a wide range of ecological disciplines are increasingly interested in assessing immunocompetence in their study organisms. One of the key challenges to researchers is determining what eco-immune measures to use in a given experiment. Moreover, there are limitations depending on study species, requirements for specific antibodies, and relevance of the methodology to the study organism. Here we introduce an improved ex vivo method for microbiocidal activity across vertebrate species. The utility of this assay is that it determines the ability of an organism to remove a pathogen that …

Widespread Triploidy In Western North American Aspen (Populus Tremuloides), Karen E. Mock, Colin M. Callahan, M. Nurul Islam-Faridi, John D. Shaw, Hardeep S. Rai, Stewart C. Sanderson, Carol A. Rowe, Ronald J. Rye, Michael D. Madritch, Richard S. Gardner, Paul G. Wolf

Biology Faculty Publications

We document high rates of triploidy in aspen (Populus tremuloides) across the western USA (up to 69% of genets), and ask whether the incidence of triploidy across the species range corresponds with latitude, glacial history (as has been documented in other species), climate, or regional variance in clone size. Using a combination of microsatellite genotyping, flow cytometry, and cytology, we demonstrate that triploidy is highest in unglaciated, drought-prone regions of North America, where the largest clone sizes have been reported for this species. While we cannot completely rule out a low incidence of undetected aneuploidy, tetraploidy or duplicated loci, our …

Methodological Tools, Ethan P. White, Xiao Xiao, J. B. Nick, Richard M. Sibly

Biology Faculty Publications

Methodological approaches for comparing metabolic theory predictions to empirical data fall into two general categories: 1) determining if the general functional form of a relationship predicted by the theory is valid; and 2) determining whether the observed values of the parameters match the specific quantitative predictions made by the theory. Both of these categories of analysis rely on being able to accurately determine the best fitting form of a model with the same general functional form as that of MTE, so we will begin by discussing how this has typically been done using OLS regression on appropriately transformed data. Potential …

Investigating Human Impact In The Environment With Faded Scaffolded Inquiry Supported By Technologies, D. T. Longhurst, M. Longhurst, A. M. Duffy, Paul G. Wolf

Biology Faculty Publications

Teaching science as inquiry is advocated in all national science education documents and by leading science and science teaching organizations. In addition to teaching science as inquiry, we recognize that learning experiences need to connect to students’ lives. This article details how we use a sequence of faded scaffolded inquiry supported by technologies to engage students meaningfully in science connected to their lives and schoolyards. In this approach, more teacher guidance is provided earlier in the inquiry experiences before this is faded later in the sequence, as students are better prepared to complete successful inquiries. The sequence of inquiry experiences …

Direct Fitness Correlates And Thermal Consequences Of Facultative Aggregation In A Desert Lizard, Alison R. Davis Rabosky, Ammon Corl, Heather E.M. Liwanag, Yann Surget-Groba, Barry Sinervo

Biology Faculty Publications

Social aggregation is a common behavioral phenomenon thought to evolve through adaptive benefits to group living. Comparing fitness differences between aggregated and solitary individuals in nature – necessary to infer an evolutionary benefit to living in groups – has proven difficult because communally-living species tend to be obligately social and behaviorally complex. However, these differences and the mechanisms driving them are critical to understanding how solitary individuals transition to group living, as well as how and why nascent social systems change over time. Here we demonstrate that facultative aggregation in a reptile (the Desert Night Lizard, Xantusia vigilis) confers …

Reproducible Hairy Root Transformation And Spot-Inoculation Methods To Study Root Symbioses Of Pea, Scott R. Clemow, Lindsey Clairmont, Lene H. Madsen, Frédérique C. Guinel

Biology Faculty Publications

Pea has lagged behind other model legumes in the molecular study of nodulation and mycorrhizae-formation because of the difficulty to transform its roots and its poor growth on agar plates. Here we describe for pea 1) a transformation technique which permits the complementation of two known non-nodulating pea mutants, 2) a rhizobial inoculation method which allows the study of early cellular events giving rise to nodule primordia, and 3) a targeted fungal inoculation method which allows us to study short segments of mycorrhizal roots assured to be infected. These tools are certain to advance our knowledge of pea root symbioses.