Biology Commons^™

Different Gene-Specific Mechanisms Determine The ‘Revised-Response’ Memory Transcription Patterns Of A Subset Of A. Thaliana Dehydration Stress Responding Genes, Ning Liu, Yong Ding, Michael Fromm, Zoya Avramova

School of Biological Sciences: Faculty Publications

Plants that have experienced several exposures to

dehydration stress show increased resistance to future

exposures by producing faster and/or stronger

reactions, while many dehydration stress responding

genes in Arabidopsis thaliana super-induce their

transcription as a ‘memory’ from the previous encounter.

A previously unknown, rather unusual,

memory response pattern is displayed by a subset

of the dehydration stress response genes. Despite

robustly responding to a first stress, these genes

return to their initial, pre-stressed, transcript levels

during the watered recovery; surprisingly, they do

not respond further to subsequent stresses of similar

magnitude and duration. This transcriptional behavior

defines the …

H3k27me3 And H3k4me3 Chromatin Environment At Super-Induced Dehydration Stress Memory Genes Of Arabidopsis Thaliana, Ning Liu, Zoya Avramova, Michael Fromm

School of Biological Sciences: Faculty Publications

Pre-exposure to a stress may alter the plant’s cellular, biochemical, and/or transcriptional responses during future encounters as a “memory” from the previous stress. Genes increasing transcription in response to a first dehydration stress, but producing much higher transcript levels in a subsequent stress, represent the super-induced “transcription memory” genes in Arabidopsis thaliana. The chromatin environment (histone H3 tri-methylations of Lys 4 and Lys 27, H3K4me3, and H3K27me3) studied at five dehydration stress memory genes revealed existence of distinct memory-response subclasses that responded differently to CLF deficiency and displayed different transcriptional activities during the watered recovery periods. Among the most …

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 …

De Novo Transcriptome Assembly From Fat Body And Flight Muscles Transcripts To Identify Morph-Specific Gene Expression Profiles In Gryllus Firmus, Neetha Nanoth Vellichirammal, Anthony J. Zera, Rudolf J. Schilder, Cody Wehrkamp, Jean-Jack M. Riethoven, Jennifer A. Brisson

School of Biological Sciences: Faculty Publications

Wing polymorphism is a powerful model for examining many aspects of adaptation. The wing dimorphic cricket species, Gryllus firmus, consists of a long-winged morph with functional flight muscles that is capable of flight, and two flightless morphs. One (obligately) flightless morph emerges as an adult with vestigial wings and vestigial flight muscles. The other (plastic) flightless morph emerges with fully-developed wings but later in adulthood histolyzes its flight muscles. Importantly both flightless morphs have substantially increased reproductive output relative to the flight-capable morph. Much is known about the physiological and biochemical differences between the morphs with respect to adaptations …

On The Helminth Fauna Of Small Mammals In Hustai National Park, Mongolia, Sumiya Ganzorig, Nyamsuren Batsaikhan, Katsuro Hagiwara, Scott Lyell Gardner, Kenji Baba, Buho Hoshino

Scott L. Gardner Publications

Introduction

The Hustai National Park is one of the special protected areas in Mongolia. The park is famous by the successful re-introduction of the wild horse (takhi), and its well-managed protection work. The park has a rich and diverse mammal fauna and flora. Of these, the takhi, and other large mammal species are objects of intensive research by the international researchers, but the parasitic helminth fauna in Hustai National Park is remained unknown. Species diversity of wildlife and its abundance, especially high density of both the prey and predators, might allow the presence of various parasitic and symbiotic organisms on …

Genome-Wide Gene Expression Effects Of Sex Chromosome Imprinting In Drosophila, Bernardo Lemos, Alan T. Branco, Pan-Pan Jiang, Daniel L. Hartl, Colin D. Meiklejohn

School of Biological Sciences: Faculty Publications

Imprinting is well-documented in both plant and animal species. In Drosophila, the Y chromosome is differently modified when transmitted through the male and female germlines. Here, we report genome-wide gene expression effects resulting from reversed parent-of-origin of the X and Y chromosomes. We found that hundreds of genes are differentially expressed between adult male Drosophila melanogaster that differ in the maternal and paternal origin of the sex chromosomes. Many of the differentially regulated genes are expressed specifically in testis and midgut cells, suggesting that sex chromosome imprinting might globally impact gene expression in these tissues. In contrast, we observed much …

Atx1/Atcompass And The H3k4me3 Marks: How Do They Activate Arabidopsis Genes?, Michael E. Fromm, Zoya Avramova

School of Biological Sciences: Faculty Publications

Despite the proven correlation between gene transcriptional activity and the levels of tri-methyl marks on histone 3 lysine4 (H3K4me3) of their nucleosomes, whether H3K4me3 contributes to, or “registers,” activated transcription is still controversial. Other questions of broad relevance are whether histone-modifying proteins are involved in the recruitment of Pol II and the general transcription machinery and whether they have roles other than their enzyme activities. We address these questions as well as the roles of the ARABIDOPSIS HOMOLOG OF TRITHORAX1 (ATX1), of the COMPASS-related (AtCOMPASS) protein complex, and of their product, H3K4me3, at ATX1-dependent genes. We suggest that the ambiguity …

Endogenous Aba Extraction And Measurement From Arabidopsis Leaves, Ning Liu, Yong Ding, Michael Fromm, Zoya Avramova

School of Biological Sciences: Faculty Publications

The endogenous messenger, the phytohormone abscisic acid (ABA) plays a major role in plant’s adaption to drought, salinity, cold and other abiotic stresses. In addition to abiotic stress signaling, ABA is involved also in developmental regulation and in responses to diverse biotic stresses. Dehydration stress results in a strong increase in endogenous ABA levels, which can be perceived by RCAR/PYR1/PYL receptors, initiating the ABA signaling pathway to coordinate the genome-wide gene expression, and plants adaptive physiological responses. ABA biosynthesis triggered by environmental cues as well as developmental signals occurs predominantly in vascular parenchyma cells. The measurement of ABA content in …

Aba Signaling Is Necessary But Not Sufficient For Rd29b Transcriptional Memory During Successive Dehydration Stresses In Arabidopsis Thaliana, Laetitia Virlouvet, Yong Ding, Hiroaki Fujii, Zoya Avramova, Michael Fromm

School of Biological Sciences: Faculty Publications

Plants subjected to a prior dehydration stress were seen to have altered transcriptional responses during a subsequent dehydration stress for up to 5 days after the initial stress. The abscisic acid (ABA) inducible RD29B gene of Arabidopsis thaliana was strongly induced after the first stress and displayed transcriptional memory with transcript levels nine-fold higher during the second dehydration stress. These increased transcript levels were due to an increased rate of transcription and are associated with an altered chromatin template during the recovery interval between the dehydration stresses. Here we use a combination of promoter deletion/substitutions, mutants in the trans-acting …

An Assembly Of Proteins And Lipid Domains Regulates Transport Of Phosphatidylserine To Phosphatidylserine Decarboxylase 2 In Saccharomyces Cerevisiae, Wayne R. Riekhof, Wen-I Wu, Jennifer L. Jones, Mrinalini Nikrad, Mallory M. Chan, Christopher J. R. Loewen, Dennis R. Voelker

School of Biological Sciences: Faculty Publications

Background: The machinery for interorganelle phosphatidylserine (PtdSer) transport is poorly defined at the molecular level.

Results: Molecular interaction studies identify specific protein-protein and protein-lipid interactions in PtdSer transport.

Conclusion: A protein and lipid interaction network defines key participants in PS transport to the locus of PtdSer-decarboxylase 2.

Significance: This study identifies important molecular participants involved in non-vesicular phospholipid traffic.

Detection Of Predator Cues Alters Mating Tactics In Male Wolf Spiders, Dustin J. Wilgers, Daniel Wickwire, Eileen Hebets

Eileen Hebets Publications

Males of the wolf spider, Rabidosa punctulata, exhibit condition-dependent alternative mating tactics, whereby small, poor condition males engage in multimodal courtship while large, good condition males adopt a direct mount tactic that forgoes courtship. This study explores the possibility that tactic-specific costs can help explain this unintuitive pattern of mating tactic expression. Specifically, we hypothesize that courtship signaling is costly with respect to eavesdropping by predators and that males can alter their tactic expression based upon the perceived environmental predation risk. We test this by first examining the risk of predation associated with different mating tactics. We use a …

The Roles Of Cis- And Trans-Regulation In The Evolution Of Regulatory Incompatibilities And Sexually Dimorphic Gene Expression, Colin D. Meiklejohn, Joseph D. Coolon, Daniel L. Hartl, Patricia J. Wittkopp

School of Biological Sciences: Faculty Publications

Evolutionary changes in gene expression underlie many aspects of phenotypic diversity within and among species. Understanding the genetic basis for evolved changes in gene expression is therefore an important component of a comprehensive understanding of the genetic basis of phenotypic evolution. Using interspecific introgression hybrids, we examined the genetic basis for divergence in genome-wide patterns of gene expression between Drosophila simulans and Drosophila mauritiana. We find that cis-regulatory and trans-regulatory divergences differ significantly in patterns of genetic architecture and evolution. The effects of cis-regulatory divergence are approximately additive in heterozygotes, quantitatively different between males and females, …

In Memoriam: Robert Lloyd Rausch—A Life In Nature And Field Biology, 1921–2012, Eric P. Hoberg

Harold W. Manter Laboratory of Parasitology: Faculty Publications

During his distinguished career, Robert Rausch, a man of great integrity and principles, served in his lifetime as a singular ambassador for parasitology in a broad international arena. Robert was a friend to many, was honored to be considered an equal among the nomadic bands of Nunamiut traversing the Brooks Range 60 years ago, and will be long remembered for the strength of his science and his perceptive views of the natural world.

Integrating Evolutionary And Functional Tests Of Adaptive Hypotheses: A Case Study Of Altitudinal Differentiation In Hemoglobin Function In An Andean Sparrow, Zonotrichia Capensis, Zachary A. Cheviron, Chandrasekhar Natarajan, Joana Projecto-Garcia, Douglas K. Eddy, Jennifer Jones, Matthew D. Carling, Christopher C. Witt, Hideaki Moriyama, Roy E. Weber, Angela Fago, Jay F. Storz

School of Biological Sciences: Faculty Publications

In air-breathing vertebrates, the physiologically optimal blood-O_² affinity is jointly determined by the prevailing partial pressure of atmospheric O₂, the efficacy of pulmonary O₂ transfer, and internal metabolic demands. Consequently, genetic variation in the oxygenation properties of hemoglobin (Hb) may be subject to spatially varying selection in species with broad elevational distributions. Here we report the results of a combined functional and evolutionary analysis of Hb polymorphism in the rufouscollared sparrow (Zonotrichia capensis), a species that is continuously distributed across a steep elevational gradient on the Pacific slope of the Peruvian Andes. We integrated …

Patterns Of Maximum Body Size Evolution In Cenozoic Land Mammals: Eco-Evolutionary Processes And Abiotic Forcing, Juha J. Saarinen, Alison G. Boyer, James H. Brown, Daniel P. Costa, S.K. Morgan Ernest, Alistair R. Evans, Mikael Fortelius, John L. Gittleman, Marcus J. Hamilton, Larisa E, Harding, Kari Lintulaakso, S. Kathleen Lyons, Jordan G. Okie, Richard M. Sibly, Patrick R. Stephens, Jessica Theodor, Mark D. Uhen, Felisa A. Smith

School of Biological Sciences: Faculty Publications

There is accumulating evidence that macroevolutionary patterns of mammal evolution during the Cenozoic follow similar trajectories on different continents. This would suggest that such patterns are strongly determined by global abiotic factors, such as climate, or by basic eco-evolutionary processes such as filling of niches by specialization. The similarity of pattern would be expected to extend to the history of individual clades. Here, we investigate the temporal distribution of maximum size observed within individual orders globally and on separate continents. While the maximum size of individual orders of large land mammals show differences and comprise several families, the times at …

Bioc 435: Advanced Topics In Biochemistry—A Peer Review Of Teaching Project Benchmark Portfolio, Edward N. Harris

UNL Faculty Course Portfolios

BIOC 435 or Advanced Topics in Biochemistry is an ACE 10 (Achievement centered education)course for students in their senior year. This is a capstone course for Biochemistry majors and is the last of several biochemistry courses that they will take in their undergraduate enrollment. The course is also open to non-majors in a related science such as Biology and Biological Sciences, although these students typically do not do as well as the majors. Students who take this course should be well-prepared in the basic concepts of biochemistry with regards to nucleic acids and proteins as well as some familiarity with …

Transcriptional Regulation Of The Porcine Gnrh Receptor Gene By Glucocorticoids, Chanho Lee

Department of Animal Science: Dissertations, Theses, and Student Research

Binding of GnRH to its receptor (GnRHR) stimulates the synthesis and secretion of the gonadotropins, as well as up-regulation of GnRHR. Thus, the interaction between GnRH and GnRHR represents a central point for regulation of reproduction. Glucocorticoids alter reproduction by reducing GnRH responsiveness of gonadotropes within the anterior pituitary gland, potentially via transcriptional regulation of the GnRHR gene. Investigation into this mechanism, however, revealed that the murine GnRHR gene was stimulated by glucocorticoids. To determine the effect of glucocorticoids on porcine GnRHR gene expression, gonadotrope-derived αT3-1 cells were transiently transfected with a vector containing 5118 bp of 5’ flanking sequence …