Biology Commons^™

Quorum Sensing Activity And Control Of Yeast-Mycelium Dimorphism In Ophiostoma Floccosum, Alexander Berrocal, Claudia Oviedo, Kenneth W. Nickerson, José Navarrete

School of Biological Sciences: Faculty Publications

Quorum sensing (QS) activity in Ophiostoma fungi has not been described. We have examined the growth conditions on the control of dimorphism in Ophiostoma floccosum, an attractive biocontrol agent against blue-stain fungi, and its relationship with QS activity. In a defined culture medium with l-proline as the N source, a high inoculum size (10⁷ c.f.u. ml^-1) was the principal factor that promoted yeast-like growth. Inoculum size effect can be explained by the secretion of a QS molecule(s) (QSMs) responsible for inducing yeast morphology. QSM candidates were extracted from spent medium and their structure was determined by GC–MS. …

The Importance Of Rare Species: A Trait-Based Assessment Of Rare Species Contributions To Functional Diversity And Possible Ecosystem Function In Tall-Grass Prairies, Meha Jain, Dan F.B. Flynn, Case M. Prager, Georgia M. Hart, Caroline M. Devan, Farshid S. Ahrestani, Matthew I. Palmer, Daniel E. Bunker, Johannes M. H. Knops, Claire F. Jouseau, Shahid Naeem

School of Biological Sciences: Faculty Publications

The majority of species in ecosystems are rare, but the ecosystem consequences of losing rare species are poorly known. To understand how rare species may influence ecosystem functioning, this study quantifies the contribution of species based on their relative level of rarity to community functional diversity using a trait-based approach. Given that rarity can be defined in several different ways, we use four different definitions of rarity: abundance (mean and maximum), geographic range, and habitat specificity. We find that rarer species contribute to functional diversity when rarity is defined by maximum abundance, geographic range, and habitat specificity. However, rarer species …

Nocturnal Homing In The Tropical Amblypygid Phrynus Pseudoparvulus (Class Arachnida, Order Amblypygi), Eileen Hebets, E.J. Gering, Verner P. Bingman, Daniel D. Wiegmann

Eileen Hebets Publications

Arthropods are renowned for their navigational capabilities, with numerous examples known from insects and crustaceans. Early studies of amblypygids (Class Arachnida, Order Amblypygi) also suggest complex nocturnal navigation, despite their apparent lack of visual adaptations to the low-light conditions of a tropical understory. In a series of two studies, we use the tropical amblypygid, Phrynus pseudoparvulus, to assess their nocturnal homing ability. Our first experiment displaced and tracked resident and nonresident individuals. Resident individuals, displaced up to 4.5 m from their home refuges and released onto their home tree, were more likely to return to their previously occupied refuge than …

Demographic Variation And Habitat Specialization Of Tree Species In A Diverse Tropical Forest Of Cameroon, David Kenfack, George B. Chuyong, Richard Condit, Sabrina E. Russo, Duncan W. Thomas

School of Biological Sciences: Faculty Publications

Background: Many tree species in tropical forests have distributions tracking local ridge-slope-valley topography. Previous work in a 50-ha plot in Korup National Park, Cameroon, demonstrated that 272 species, or 63% of those tested, were significantly associated with topography.

Methods: We used two censuses of 329,000 trees ≥1 cm dbh to examine demographic variation at this site that would account for those observed habitat preferences. We tested two predictions. First, within a given topographic habitat, species specializing on that habitat (‘residents’) should outperform species that are specialists of other habitats (‘foreigners’). Second, across different topographic habitats, species should perform best …

Bridging Physics And Biology Teaching Through Modeling, Anne-Marie Hoskinson, Brian A. Couch, Benjamin M. Zwickl, Kathleen A. Hinko, Marcos D. Caballero

School of Biological Sciences: Faculty Publications

As the frontiers of biology become increasingly interdisciplinary, the physics education community has engaged in ongoing efforts to make physics classes more relevant to life science majors. These efforts are complicated by the many apparent differences between these fields, including the types of systems that each studies, the behavior of those systems, the kinds of measurements that each makes, and the role of mathematics in each field. Nonetheless, physics and biology are both sciences that rely on observations and measurements to construct models of the natural world. In this article, we propose that efforts to bridge the teaching of these …

Effect Of Prey Richness On A Consumer’S Intrinsic Growth Rate, Brian J. Darby, Michael A. Herman

School of Biological Sciences: Faculty Publications

The intrinsic growth rate of nonselective microbivores increases asymptotically with increasing prey biomass, but we do not know how intrinsic growth rate is affected by prey richness. The objective of this experiment was to determine the effect of prey richness on the growth kinetics of nematode predators while grazing on mixed bacterial lawns. We found that the intrinsic growth rate of Caenorhabditis elegans in laboratory culture increased asymptotically with prey richness. The mechanism of this pattern was primarily due to the best available prey species in the mixture: the intrinsic growth rate of the consumer feeding on a mixture of …

Eutrophication Weakens Stabilizing Effects Of Diversity In Natural Grasslands, Yann Hautier, Eric W. Seabloom, Elizabeth T. Borer, Peter B. Adler, W. Stanley Harpole, Helmut Hillebrand, Eric M. Lind, Andrew S. Macdougall, Carly J. Stevens, Jonathan D. Bakker, Yvonne M. Buckley, Chengjin Chu, Scott L. Collins, Pedro Daleo, Ellen I. Damschen, Kendi F. Davies, Philip A. Fay, Jennifer Firn, Daniel S. Gruner, Virginia L. Jin, Julia A. Klein, Johannes M. H. Knops, Kimberly J. La Pierre, Wei Li, Rebecca L. Mcculley, Brett A. Melbourne, Joslin L. Moore, Lydia R. O’Halloran, Suzanne M. Prober, Anita C. Risch, Mahesh Sankaran, Martin Schuetz, Andy Hector

School of Biological Sciences: Faculty Publications

Studies of experimental grassland communities^1–7 have demonstrated that plant diversity can stabilize productivity through species asynchrony, in which decreases in the biomass of some species are compensated for by increases in others^1,2. However, it remains unknown whether these findings are relevant to natural ecosystems, especially those for which species diversity is threatened by anthropogenic global change^8–11. Here we analyse diversity–stability relationships from 41 grasslands on five continents and examine how these relationships are affected by chronic fertilization, one of the strongest drivers of species loss globally⁸. Unmanipulated communities with more species had greater …

Dehydration Stress Memory Genes Of Zea Mays; Comparison With Arabidopsis Thaliana, Yong Ding, Laetitia Virlouvet, Ning Liu, Jean-Jack Riethoven, Michael E. Fromm, Zoya Avramova

School of Biological Sciences: Faculty Publications

Background: Pre-exposing plants to diverse abiotic stresses may alter their physiological and transcriptional responses to a subsequent stress, suggesting a form of “stress memory”. Arabidopsis thaliana plants that have experienced multiple exposures to dehydration stress display transcriptional behavior suggesting “memory” from an earlier stress. Genes that respond to a first stress by up-regulating or down-regulating their transcription but in a subsequent stress provide a significantly different response define the ‘memory genes’ category. Genes responding similarly to each stress form the ‘non-memory’ category. It is unknown whether such memory responses exists in other Angiosperm lineages and whether memory is an evolutionarily …

Using An Ecosystem Approach To Complement Protection Schemes Based On Organism-Level Endpoints, Clare Bradshaw, Lawrence Kapustka, Lawrence Barenthouse, Justin Brown, Philippe Ciffroy, Valery E. Forbes, Stanislav Geras'kin, Ulrik Kautsky, Francois Brechignac

School of Biological Sciences: Faculty Publications

Radiation protection goals for ecological resources are focused on ecological structures and functions at population-, community-, and ecosystem-levels. The current approach to radiation safety for non-human biota relies on organism-level endpoints, and as such is not aligned with the stated overarching protection goals of international agencies. Exposure to stressors can trigger non-linear changes in ecosystem structure and function that cannot be predicted from effects on individual organisms. From the ecological sciences, we know that important interactive dynamics related to such emergent properties determine the flows of goods and services in ecological systems that human societies rely upon. A previous Task …

Effect Of The Internet Commerce On Dispersal Modes Of Invasive Alien Species, Magdalena Lenda, Piotr Skorka, Johannes M.H. Knops, Dawid Moron, William J. Sutherland, Karolina Kuszewska, Michal Woyciechowski

School of Biological Sciences: Faculty Publications

The spread of invasive alien plants has considerable environmental and economic consequences, and is one of the most challenging ecological problems. The spread of invasive alien plant species depends largely on long-distance dispersal, which is typically linked with human activity. The increasing domination of the internet will have impacts upon almost all components of our lives, including potential consequences for the spread of invasive species. To determine whether the rise of Internet commerce has any consequences for the spread of invasive alien plant species, we studied the sale of thirteen of some of the most harmful Europe invasive alien plant …

Loss Of Sirt1 Function Improves Intestinal Anti-Bacterial Defense And Protects From Colitis-Induced Colorectal Cancer, Giuseppe Lo Sasso, Dongryeol Ryu, Laurent Mouchiroud, Samodha C. Fernando, Christopher L. Anderson, Elena Katsyuba, Alessandra Piersigilli, Michael O. Hottiger, Kristina Schoonjans, Johan Auwerx

School of Biological Sciences: Faculty Publications

Dysfunction of Paneth and goblet cells in the intestine contributes to inflammatory bowel disease (IBD) and colitisassociated colorectal cancer (CAC). Here, we report a role for the NAD⁺-dependent histone deacetylase SIRT1 in the control of anti-bacterial defense. Mice with an intestinal specific Sirt1 deficiency (Sirt1^int-/-) have more Paneth and goblet cells with a consequent rearrangement of the gut microbiota. From a mechanistic point of view, the effects on mouse intestinal cell maturation are mediated by SIRT1-dependent changes in the acetylation status of SPDEF, a master regulator of Paneth and goblet cells. Our results suggest that targeting …

Effects Of Nitrogen And Phosphorus Fertilization On Soil Carbon Fractions In Alpine Meadows On The Qinghai-Tibetan Plateau, Jin Hua Li, Yu Jie Yang, Bo Wen Li, Wen Jin Li, Gang Wang, Johannes M. H. Knops

School of Biological Sciences: Faculty Publications

In grassland ecosystems, N and P fertilization often increase plant productivity, but there is no concensus if fertilization affects soil C fractions. We tested effects of N, P and N+P fertilization at 5, 10, 15 g m^-2 yr^-1 (N₅, N₁₀, N₁₅, P₅, P₁₀, P₁₅, N₅P₅, N₁₀P₁₀, and N₁₅P₁₅) compared to unfertilized control on soil C, soil microbial biomass and functional diversity at the 0– 20 cm and 20–40 cm depth in an alpine meadow …

Effects Of Virus On Plant Fecundity And Population Dynamics, Holly R. Prendeville, Brigitte Tenhumberg, Diana Pilson

Brigitte Tenhumberg Papers

Microorganisms are ubiquitous and thought to regulate host populations. Although microorganisms can be pathogenic and affect components of fitness, few studies have examined their effects on wild plant populations. As individual traits might not contribute equally to changes in population growth rate, it is essential to examine the entire life cycle to determine how microorganisms affect host population dynamics. In this study, we used data from common garden experiments with plants from three Cucurbita pepo populations exposed to three virus treatments. These data were used to parameterize a deterministic matrix model, which allowed us to estimate the effect of virus …

Serial Cervicovaginal Exposures With Replication-Deficient Sivsm Induce Higher Dendritic Cell (Pdc) And Cd4+ T-Cell Infiltrates Not Associated With Prevention But A More Severe Sivmac251 Infection Of Rhesus Macaques, Shaheed A. Abdulhaqq, Melween I. Martinez, Guobin Kang, Andrea S. Foulkes, Idia V. Rodriguez, Stephanie M. Nichols, Meredith Hunter, Carlos A. Sariol, Lynnette A. Ruiz, Brian N. Ross, Xiangfan Yin, David W. Speicher, Ashley T. Haase, Preston A. Marx, Qingsheng Li, Edmundo N. Kraiselburd, Luis J. Montaner

Qingsheng Li Publications

Objective: Intravaginal exposure to simian immunodeficiency virus (SIV) acutely recruits interferon-alpha (IFN-α) producing plasmacytoid dendritic cells (pDC) and CD4+ T-lymphocyte tar-gets to the endocervix of nonhuman primates. We tested the impact of repeated cervicovaginal ex-posures to noninfectious, defective SIV particles over 72 hours on a subsequent cervicovaginal challenge with replication competent SIV. Methods: Thirty-four female Indian Rhesus macaques were given a 3-day twice-daily vaginal exposures to either SIVsmB7, a replication deficient derivative of SIVsmH3 produced by a T lymphoblast CEMx174 cell clone (n = 16), or to CEM supernatant controls (n = 18). On the fourth day, animals were either …

Revision Of Anacaena Thomson, 1859 Xi. Republic Of The Philippines (Coleoptera: Hydrophilidae), Hendrik Freitag

Biology Faculty Publications

The species of Anacaena THOMSON, 1859 (Coleoptera: Hydrophilidae) of the Republic of the Philippines are revised. Fifteen new species are described: Anacaena albay sp.n., A. amplocomata sp.n., A. apo sp.n., A. balabag sp.n., A. cordillera sp.n., A. davao sp.n., A. destructa sp.n., A. emergens sp.n., A. hemisphaerica sp.n., A. levistriata sp.n., A. philippina sp.n., A. princesa sp.n., A. quezona sp.n., A. sulcata sp.n., and A. zamboangana. All species are endemic to the Philippines, twelve are aquatic, the habitat of three species is unknown. All Philippine species are morphologically similar to other species of the eastern Oriental Region and probably do …

A Mega-Diverse Water Beetle Genus (Coleoptera: Hydraenidae: Hydraena Kugelann) Commonly Overlooked In Southeast Asia And Its Potential Use For Environmental Biomonitoring, Hendrik Freitag

Biology Faculty Publications

This study summarizes the current knowledge of the water beetle genus Hydraena Kugelann in Southeast Asia. The surprising species diversity and endemism rates in Hydraenopsis Janssens, the only subgenus present in Southeast Asia, are discussed. Data of five published Hydraena surveys from the Philippines and Singapore are used to evaluate species richness and the occurrence of species assemblages that are subject to the presence and quality of forests. Species richness was found to be generally higher in old grown forests. Some species appeared to be confined to near-natural forests. The denomination of indicator species is impeded by adequate sampling data, …

Evaluation Of The Three-Dimensional Patterns And Ecological Impacts Of The Invasive Old World Climbing Fern (Lygodium Microphyllum), Alexis Maldonado

Electronic Theses and Dissertations

Invasion by non-native species has had significant ecological and economic impacts on a global scale. In the state of Florida, Old World climbing fern (Lygodium microphyllum) is an invasive plant listed by FLEPPC as a category one invader with significant ecological impacts that threaten native plant diversity. This species relies on existing vegetative structures for support to climb into the forest canopy and forms dense mats that cover tree crowns. This subsequently affects the resources available to other species present. Quantifying the structural changes due to the presence of this species has proved logistically difficult, especially on a large spatial …

An Examination Of Music's Effects On Athletic Performance, Patrick Ford

A with Honors Projects

This paper is an investigation of how music can impact athletic performance and the biological pathways that it acts through.

Assessing The In Situ Fertilization Status Of Two Marine Copepod Species, Temora Longicornis And Eurytemora Herdmani; How Common Are Unfertilized Eggs In Nature?, Rachel S. Lasley-Rasher, Andrew M. Kramer, Victoria Burdett-Coutts, Jeannette Yen

Integrative Biology Faculty and Staff Publications

We utilized an egg staining technique to measure the in situ fertilization success of two marine copepod species, Temora longicornis and Eurytemora herdmani from May to October 2008 in coastal Maine and correlated fertilization success with environmental conditions in their habitat. T. longicornis is a free spawning species that releases eggs into the ambient seawater after mating. In contrast, E. herdmani carries eggs in an egg sac until they hatch. The proportion of fertilized eggs within E. herdmani egg sacs was significantly higher than the freely spawned clutches of T. longicornis. This may be a result of the asymmetrical costs …

Ether Bridge Formation And Chemical Diversification In Loline Alkaloid Biosynthesis, Juan Pan

Theses and Dissertations--Plant Pathology

Loline alkaloids, found in many grass-Epichloë symbiota, are toxic or feeding deterrent to invertebrates. The loline alkaloids all share a saturated pyrrolizidine ring with a 1-amine group and an ether bridge linking C2 and C7. The steps in biosynthesis of loline alkaloids are catalyzed by enzymes encoded by a gene cluster, designated LOL, in the Epichloë genome. This dissertation addresses the enzymatic, genetic and evolutionary basis for diversification of these alkaloids, focusing on ether bridge formation and the subsequent modifications of the 1-amine to form different loline alkaloids.

Through gene complementation of a natural lolO mutant and comparison …

Approaches To Restoration: Assessing The Roles Of Structure And Function In Saltmarsh Restoration In Light Of Climate Change, Abby O. Pearson Ms

All Student Scholarship

The aim of this thesis is to review the current goals and methods for salt marsh restoration, to question how those goals and methods may change in light of global change, and to present a case study that offers a look at the kinds of information that can be gleaned by studying both structure and functionality in restoration.

Clinical Features And Outcome Of Sporadic Colorectal Carcinoma In Young Patients: A Cross-Sectional Analysis From A Developing Country, Muhammad Nauman Zahir, Eisha Mahpara Azhar, Sobia Rafiq, Kulsoom Ghias, Munira Shabbir-Moosajee

Department of Biological & Biomedical Sciences

Background: Early onset colorectal carcinoma (CRC) is rare and has been hypothesized to be a biologically and clinically distinct entity personifying aggressive disease and worse survival.
Methods: Data for 131 patients was collected by retrospective chart review. Cox proportional hazard model was used to compute prevalence ratios and 95% confidence intervals.
Results: Early onset sporadic CRC accounted for 32% of all CRC treated in the specified time period. The mean age was 33.3 ± 7.9 years and the male to female ratio was 2 : 1. Colon and rectal cancers accounted for 55% and 45% of patients, respectively. 96% of …

Beta Diversity Of Urban Floras Among European And Non-European Cities, Frank A. La Sorte, Myla F.J. Aronson, Nicholas S.G. Williams, Laura Celesti-Grapow, Sarel Cilliers, Bruce D. Clarkson, Rebecca W. Dolan, Andrew Hipp, Stefan Klotz, Ingolf Kühn, Pter Pyšek, Stefan Siebert, Marten Winter

Scholarship and Professional Work - LAS

Aim- Cities represent an ideal study system for assessing how intensive land-use change and biotic interchange have altered beta diversity at broad geographic extents. Here we test the hypothesis that floras in cities located in disparate regions of the globe are being homogenized by species classified as invasive (naturalized species that have spread over a large area) or as a European archaeophyte (species introduced into Europe before ad 1500 from the Mediterranean Basin). We also test the prediction that the global influences of European activities (colonization, agriculture, commerce) have supported this outcome.

Location- One hundred and ten cities …

A Revision Of The Octocoral Genus Ovabunda Alderslade, 2001 (Anthozoa, Octocorallia, Xeniidae), Catherine S. Mcfadden, Yehuda Benayahu, Anna Halász, Dafna Aharonovich, Robert Toonen

All HMC Faculty Publications and Research

The family Xeniidae (Octocorallia) constitutes an abundant benthic component on many Indo-West Pacific coral reefs and is ecologically important in the Red Sea. The genus Ovabunda Alderslade, 2001 was recently established to accommodate previous Xenia species with sclerites comprised of a mass of minute corpuscle-shaped microscleres. The aim of the present study was to examine type material of Xenia species in order to verify their generic affiliation. We present here a comprehensive account of the genus Ovabunda, using scanning electron microscopy to depict sclerite microstructure. We assign three Xenia species to the genus: O. ainex comb. n., O. …

A New Species Of Ovabunda (Octocorallia, Xeniidae) From The Andaman Sea, Thailand With Notes On The Biogeography Of This Genus, Catherine S. Mcfadden, Michael P. Janes, Thanongsak Chanmethakul

All HMC Faculty Publications and Research

A survey of xeniid octocorals was carried out in the waters off Southwestern Thailand in September, 2007. Microscopic investigation of the colonies revealed that three specimens belonged to the genus Ovabunda. Gross morphological examination is presented here accompanied by scanning electron micrographs of the sclerites. Molecular phylogenetic analysis showed identical genotypes at mtMutS, COI, and 28S rDNA for all three specimens and supports their generic assignment. Colony size and shape, sclerite size, and pinnule arrangement differ from nominal species of Ovabunda and thus a new species, O. andamanensis is introduced here. This work also presents a new …

The Genetics Of Hybrid Incompatibility Early In The 'Speciation Continuum', Eric Watson

Biology Dissertations - Archive

Species are discrete groups of organisms that are reproductively isolated from other related groups of organisms. Variation in the strength of reproductive isolation between closely related taxa falls along a `speciation continuum', from weakly isolated structured populations to fully isolated sister species. Efforts to understand the genetics of speciation have focused primarily on developmental defects in hybrids (intrinsic postzygotic isolation) leading to sterility or inviability. Once speciation is complete, species continue to diverge as a result of mutation, genetic drift, and selection, and new forms of reproductive isolation may continue to accumulate. Therefore, at later stages in the `speciation continuum', …

The Genetic Architecture Of Variation In Humans And Dogs, Eldon Goodwin Prince

Biology Dissertations - Archive

Genetic architecture is broadly defined as the structure of how genes come together to produce phenotypes. Primary aspects of genetic architecture include how many and which genes contribute to phenotypic variation. The genetic architecture of human height has been studied for over a century; indeed it is the classic quantitative trait with hundreds of contributing variants. As genome-wide studies of genetic architecture are extended beyond just humans, the genetic basis of polygenic traits like height can be compared between species. Such interspecies comparisons reveal how many of the same loci contribute to variation within each species. The extent to which …

Mechanisms Affecting Predation Success In Wolf Spiders, Matthew Steffenson

Biology Dissertations - Archive

Predator-prey interactions play a role in community structure through a variety of different mechanisms including direct consumption, density-mediated indirect effects, and trait-mediated indirect effects. Understanding factors that can influence the efficacy of direct consumption on prey populations can help us to identify the strength of the impact predators can have on lower trophic levels. My dissertation research focuses on how mechanisms like sexual dimorphism, impaired body condition, and starvation stress alter how effective an intermediate predator (i.e. a predator that occupies an intermediate position in the food web) can be in direct consumption of prey. Using wolf spiders as my …

A Study Of The Function Of Two Nuclear Transport Retrogenes (Dntf-2r And Ran-Like) In Drosophila Melanogaster, Susana Filipa Simoes Lopes Domingues

Biology Dissertations - Archive

The genetic information, DNA (deoxyribonucleic acid) and RNA (ribonucleic acid), is the hereditary material that forms the basis for the origin and evolution of life. These molecules encode and store information that can be copied, read, mutated, recombined and selected, providing necessary conditions for the evolution of the diversity of life on earth. With my project I contribute to the understanding of how one class of mutations, namely gene duplication, contributes to the functional differences between species. It has been observed that many new duplicate genes originate for testis functions; not only in the Drosophila genomes but other organisms' genomes …

Investigation Of Potential Virulence Factors In Pathogenic Marine Bacteria, Joshuah Myron Beach-Letendre

Biology Theses - Archive

Coral reefs provide numerous ecological and economic functions and are critical to biodiversity in marine environments. Critical to coral reef health and diversity is the microbial consortium within the coral host along with symbiotic algae. Coral reef invertebrate-microbe interactions within coral reef communities are rapidly shifting out of equilibrium throughout the globe. Higher temperatures are believed to be responsible for this destabilization. In this study, I assessed the production of potential virulence factors in previously isolated bacteria believed to contribute to disease symptoms in a major reef building coral, Orbicella faveolata. I measured the doubling times, respiration rates, biofilm production, …