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Articles 8611 - 8640 of 9783

Full-Text Articles in Genetics and Genomics

Overexpression And Purification Of The Oat (Avena Fatua) Protein Afn1 And Construction Of A Pmal/Afn1 Expression Plasmid, Tenzin D. Tsewang Jan 2006

Overexpression And Purification Of The Oat (Avena Fatua) Protein Afn1 And Construction Of A Pmal/Afn1 Expression Plasmid, Tenzin D. Tsewang

Undergraduate Research Symposium (UGRS)

Abscisic acid (ABA) is an important phytohormone with regulatory roles in many physiological processes. ABA expression is induced by environmental stresses such as drought and it is known to be an inhibitor of seed germination. A wild oat (Avena fatua) called AFN1 has been hypothesized to initiate the early stages of germination as its mRNA accumulates in nondormant seed embryos during imbibition. The polypeptide sequence of AFN1 suggests that it is an ABA glucosyl transferase. Glucosylation by AFN1 and thereby inactivation of ABA could lead to seed germination. In order to understand the role of AFN1 in germination, an ample …


Characterization Of The Wheat Grain Pkaba1-Interacting Protein Tawd40, Natalie Wayne Jan 2006

Characterization Of The Wheat Grain Pkaba1-Interacting Protein Tawd40, Natalie Wayne

Undergraduate Research Symposium (UGRS)

Abscisic acid (ABA)-mediated gene expression is a critical component of plant responses to this important hormone, which affects plant growth, development, and responses to environmental stresses. Plant responses to ABA are mediated by a number of factors including PKABA1, an ABA induced protein kinase involved in ABA-suppressed gene expression in cereal grains, and TaWD40, which has previously been shown to physically interact with PKABA1. A full-length 1.9 kb TaWD40 cDNA, CK210682, was sequenced as part of this project. Based on the deduced protein sequence, it is thought that TaWD40 may belong to the family of E3 ubiquitin ligases, possibly targeting …


A Group M Consensus Envelope Glycoprotein Induces Antibodies That Neutralize Subsets Of Subtype B And C Hiv-1 Primary Viruses, Hua-Xin Lin, Laura L. Sutherland, Shi-Mao Xia, Mary E. Brock, Richard M. Scearce, Stacie Vanleeuwen, S. Munir Alam, Mildred Mcadams, Eric A. Weaver, Zenaido T. Camacho, Ben-Jiang Ma, Yingying Li, Julie M. Decker, Gary J. Nabel, David C. Montefiori, Beatrice H. Hahn, Bette T. Korber, Feng Gao, Barton F. Haynes Jan 2006

A Group M Consensus Envelope Glycoprotein Induces Antibodies That Neutralize Subsets Of Subtype B And C Hiv-1 Primary Viruses, Hua-Xin Lin, Laura L. Sutherland, Shi-Mao Xia, Mary E. Brock, Richard M. Scearce, Stacie Vanleeuwen, S. Munir Alam, Mildred Mcadams, Eric A. Weaver, Zenaido T. Camacho, Ben-Jiang Ma, Yingying Li, Julie M. Decker, Gary J. Nabel, David C. Montefiori, Beatrice H. Hahn, Bette T. Korber, Feng Gao, Barton F. Haynes

Nebraska Center for Virology: Faculty Publications

HIV-1 subtype C is the most common HIV-1 group M subtype in Africa and many parts of Asia. However, to date HIV-1 vaccine candidate immunogens have not induced potent and broadly neutralizing antibodies against subtype C primary isolates. We have used a centralized gene strategy to address HIV-1 diversity, and generated a group M consensus envelope gene with shortened consensus variable loops (CON-S) for comparative studies with wildtype (WT) Env immunogens. Our results indicate that the consensus HIV-1 group M CON-S Env elicited cross-subtype neutralizing antibodies of similar or greater breadth and titer than the WT Envs tested, indicating the …


Characterization Of 35 Microsatellite Loci In The Pacific Lion-Paw Scallop (Nodipecten Subnodosus) And Their Cross-Species Amplification In Four Other Scallops Of The Pectinidae Family, Ana M. Ibarra, Jessica Lynn Petersen, Thomas R. Famula, Bernie May Jan 2006

Characterization Of 35 Microsatellite Loci In The Pacific Lion-Paw Scallop (Nodipecten Subnodosus) And Their Cross-Species Amplification In Four Other Scallops Of The Pectinidae Family, Ana M. Ibarra, Jessica Lynn Petersen, Thomas R. Famula, Bernie May

Department of Animal Science: Faculty Publications

Four microsatellite-enriched DNA libraries yielded 35 microsatellite loci from 100 primer pairs designed for Pacific lion-paw scallop, Nodipecten subnodosus. The number of alleles ranged from four to 28. Three of the 35 loci were not in Hardy–Weinberg equilibrium and linkage disequilibrium was found for one pair of loci. These microsatellites will be used to analyze the population structure of the species in Mexico’s Baja Peninsula to propose management strategies for scallop aquaculture development. Twenty-six primer pairs cross-amplified in Nodipecten nodosus, whereas none (Argopecten ventricosus) or few cross-amplified in the Argopecten species.


Evolutionary Dynamics Of The Short-Nosed Fruit Bat, Cynopterus Sphinx (Pteropodidae): Inferences From The Spatial Scale Of Genetic And Phenotypic Differentiation, Jay F. Storz, Hari R. Bhat, Johnson Balasingh, P. Thiruchenthil Nathan, Thomas H. Kunz Jan 2006

Evolutionary Dynamics Of The Short-Nosed Fruit Bat, Cynopterus Sphinx (Pteropodidae): Inferences From The Spatial Scale Of Genetic And Phenotypic Differentiation, Jay F. Storz, Hari R. Bhat, Johnson Balasingh, P. Thiruchenthil Nathan, Thomas H. Kunz

Jay F. Storz Publications

We report the results of a population-genetic study of the short-nosed fruit bat, Cynopterus sphinx (Pteropodidae). The purpose of our study was to assess the relative importance of drift, gene flow, and spatially varying selection in shaping patterns of genetic and phenotypic variation across a latitudinal climatic gradient in peninsular India. At a microgeographic scale, polygynous mating resulted in a substantial reduction of effective population size. However, at a macrogeographic scale, rates of migration were sufficiently high to prevent a pronounced degree of stochastic differentiation via drift. Spatial analysis of genetic and phenotypic differentiation revealed that clinal variation in body …


A Broad-Spectrum Mer Operon In A Multi-Drug Resistant Strain Of The Fish Pathogen, Aeromonas Salmonicida, Erin Parry Jan 2006

A Broad-Spectrum Mer Operon In A Multi-Drug Resistant Strain Of The Fish Pathogen, Aeromonas Salmonicida, Erin Parry

Honors Theses

Aeromonas salmonicida AS03, a potential fish pathogen, was isolated from Atlantic salmon, Salmo salar, in 2003. This strain was found to be resistant to ≥1000 mM HgCl2 and ≥32 mM phenylmercuric acetate as well as multiple antimicrobials. Mercury (Hg) and antibiotic resistance genes are often located on the same mobile genetic elements, so the genetic determinants of both resistances and the possibility of horizontal gene transfer were examined. Specific PCR primers were used to amplify and sequence distinctive regions of the mer operon. A. salmonicida AS03 was found to have a pDU1358-like broad-spectrum mer operon, containing merB as well as …


Taking A Bite Out Of Hypertrophic Cardiomyopathy: Soy Diet And Disease, Cathy J. Hatcher, Craig T. Basson Jan 2006

Taking A Bite Out Of Hypertrophic Cardiomyopathy: Soy Diet And Disease, Cathy J. Hatcher, Craig T. Basson

PCOM Scholarly Works

Some forms of hypertrophic cardiomyopathy (HCM) are caused by mutations in cardiac sarcomeric genes, but environmental factors are believed to influence the hypertrophic response. A highly variable but potentially significant environmental factor is diet. Since soy-rich diets have been speculated to confer protection against cardiovascular disease, Stauffer et al. have explored the influence of a soy diet on cardiac growth and function in a transgenic mouse model of HCM (see the related article beginning on page 209). They report that mice fed a soy diet exhibited significantly worse HCM than mice fed a soy-free (milk protein) diet. This study provides …


Fm-Test: A Fuzzy-Set-Theory-Based Approach To Differential Gene Expression Data Analysis, Lily R. Liang, Shiyong Lu, Xuena Wang, Yi Lu, Vinay Mandal, Dorrelyn Patacsil, Deepak Kumar Jan 2006

Fm-Test: A Fuzzy-Set-Theory-Based Approach To Differential Gene Expression Data Analysis, Lily R. Liang, Shiyong Lu, Xuena Wang, Yi Lu, Vinay Mandal, Dorrelyn Patacsil, Deepak Kumar

Wayne State University Associated BioMed Central Scholarship

Abstract

Background

Microarray techniques have revolutionized genomic research by making it possible to monitor the expression of thousands of genes in parallel. As the amount of microarray data being produced is increasing at an exponential rate, there is a great demand for efficient and effective expression data analysis tools. Comparison of gene expression profiles of patients against those of normal counterpart people will enhance our understanding of a disease and identify leads for therapeutic intervention.

Results

In this paper, we propose an innovative approach, fuzzy membership test (FM-test), based on fuzzy set theory to identify disease associated genes from microarray …


Generation And Characterization Of An Allelic Series Of Ets1 Gene Targeted Mice: Thymomegaly, Microsplenia And Defective Homeostatic Proliferation Of Peripheral Lymphocytes Of Ets1Δvii But Not Ets1s->A Mice, Frank O. Bartel Jan 2006

Generation And Characterization Of An Allelic Series Of Ets1 Gene Targeted Mice: Thymomegaly, Microsplenia And Defective Homeostatic Proliferation Of Peripheral Lymphocytes Of Ets1Δvii But Not Ets1s->A Mice, Frank O. Bartel

MUSC Theses and Dissertations

Ets1 is a member of the ETS transcription factor family with demonstrated roles in cell proliferation, migration, and survival. Alternative splicing of exon VII results in two distinct protein isoforms: full length Ets1 and Ets1ΔVII. These isoforms bear key distinctions regarding protein-protein interactions, DNA binding kinetics and transcriptional target specificity. Targeted disruption of both Ets1 isoforms (Ets1 null) in mice results in increased perinatal lethality, loss of detectable NK and NKT cell activity, and differentiation, proliferation and survival defects in B- and T-Iymphocytes. To further delineate the individual roles of Ets1 isoforms in vivo we have generated an allelic series …


Eye Development At The Houston "Fly Meeting", Amit Singh Jan 2006

Eye Development At The Houston "Fly Meeting", Amit Singh

Biology Faculty Publications

Meeting report: The 47th Annual Drosophila Research Conference or "Fly Meeting" took place at Houston, Texas, USA from March 29th- April 2nd, 2006, under the aegis of the Genetics Society of America. The Fly Meeting provides an excellent opportunity for fly researchers to present their work and to get a snapshot of recent developments and upcoming trends in their research field. The fruit fly, Drosophila melanogaster, is a very versatile model to study growth, patterning, neural development, evolution, systemetics and various other facets of biomedical science. The topics presented in the meeting covered a very broad spectrum of fly research. …


Modern Biological Approaches To Folk Medicines And Traditional Antifungal Therapies, Matthew G. Jessulat, Robert P. Smith, Nadereh H. Mir-Rashed, Golshani Ashkan, John Thor Arnason, Myron L. Smith Jan 2006

Modern Biological Approaches To Folk Medicines And Traditional Antifungal Therapies, Matthew G. Jessulat, Robert P. Smith, Nadereh H. Mir-Rashed, Golshani Ashkan, John Thor Arnason, Myron L. Smith

Biology Faculty Articles

No abstract provided.


Neural Induction And Differentiation Of Stem Cells Using The Developmental Gene Pax7, Vijesh G. Vaghjiani Jan 2006

Neural Induction And Differentiation Of Stem Cells Using The Developmental Gene Pax7, Vijesh G. Vaghjiani

Theses : Honours

Neurodegenerative disorders are conditions that mainly affect the brain and the central nervous system (CNS). Each disease type is characterised by loss of function which results from death of a particular region. Interestingly enough, most of the time disease pathology is due to loss of specific cell types in the CNS. These pathological conditions have both high economic costs and social implications for society. To treat such conditions, either the lost cells must be replaced or the cells surrounding the damaged tissue must be induced to undergo repair to replace the lost cells. The former looks more achievable whereas the …


Design Clues From Functional Constraints And Broadly Neutralizing Antibodies, Tongqing Zhou, Ling Xu, Barna Dey, Ann J. Hessell, Shahzad Majeed, Donald Van Ryk, Shi-Hua Xiang, Xinzhen Yang, Mei-Yun Zhang, Michael B. Zwick, James Arthos, Dennis R. Burton, Dimiter S. Dimitrov, Joseph Sodroski, Richard Wyatt, Gary J. Nabel, Peter D. Kwong Jan 2006

Design Clues From Functional Constraints And Broadly Neutralizing Antibodies, Tongqing Zhou, Ling Xu, Barna Dey, Ann J. Hessell, Shahzad Majeed, Donald Van Ryk, Shi-Hua Xiang, Xinzhen Yang, Mei-Yun Zhang, Michael B. Zwick, James Arthos, Dennis R. Burton, Dimiter S. Dimitrov, Joseph Sodroski, Richard Wyatt, Gary J. Nabel, Peter D. Kwong

Nebraska Center for Virology: Faculty Publications

No abstract provided.


Cross-Subtype T-Cell Immune Responses Induced By A Human Immunodeficiency Virus Type 1 Group M Consensus Env Immunogen, Eric A. Weaver, Zenaido T. Camacho, Fatiha Moukdar, Hua-Xin Liao, Ben-Jiang Ma, Mark Muldoon, James Theiler, Gary J. Nabel, Norman L. Letvin, Bette T. Korber, Beatrice H. Hahn, Barton F. Haynes, Feng Gao, Zhongjing Lu Jan 2006

Cross-Subtype T-Cell Immune Responses Induced By A Human Immunodeficiency Virus Type 1 Group M Consensus Env Immunogen, Eric A. Weaver, Zenaido T. Camacho, Fatiha Moukdar, Hua-Xin Liao, Ben-Jiang Ma, Mark Muldoon, James Theiler, Gary J. Nabel, Norman L. Letvin, Bette T. Korber, Beatrice H. Hahn, Barton F. Haynes, Feng Gao, Zhongjing Lu

Nebraska Center for Virology: Faculty Publications

The genetic diversity among globally circulating human immunodeficiency virus type 1 (HIV-1) strains is a serious challenge for HIV-1 vaccine design. We have generated a synthetic group M consensus env gene (CON6) for induction of cross-subtype immune responses and report here a comparative study of T-cell responses to this and natural strain env immunogens in a murine model. Three different strains of mice were immunized with CON6 as well as subtype A, B, or C env immunogens, using a DNA prime-recombinant vaccinia virus boost strategy. T-cell epitopes were mapped by gamma interferon enzyme-linked immunospot analysis using five overlapping Env peptide …


Impacts Of Genetic Bottlenecks On Soybean Genome Diversity, D. L. Hyten, Qijian Song, Youlin Zhu, Ik-Young Choi, Randall L. Nelson, Jose M. Costa, James E. Specht, Randy C. Shoemaker, Perry B. Cregan Jan 2006

Impacts Of Genetic Bottlenecks On Soybean Genome Diversity, D. L. Hyten, Qijian Song, Youlin Zhu, Ik-Young Choi, Randall L. Nelson, Jose M. Costa, James E. Specht, Randy C. Shoemaker, Perry B. Cregan

Department of Agronomy and Horticulture: Faculty Publications

Soybean has undergone several genetic bottlenecks. These include domestication in Asia to produce numerous Asian landraces, introduction of relatively few landraces to North America, and then selective breeding over the past 75 years. It is presumed that these three human-mediated events have reduced genetic diversity. We sequenced 111 fragments from 102 genes in four soybean populations representing the populations before and after genetic bottlenecks. We show that soybean has lost many rare sequence variants and has undergone numerous allele frequency changes throughout its history. Although soybean genetic diversity has been eroded by human selection after domestication, it is notable that …


Tannerella Forsythia, A Periodontal Pathogen Entering The Genomic Era, Anne C. R. Tanner, Jacques Izard Jan 2006

Tannerella Forsythia, A Periodontal Pathogen Entering The Genomic Era, Anne C. R. Tanner, Jacques Izard

Department of Food Science and Technology: Faculty Publications

Several questions need to be addressed to evaluate whether Tannerella forsythia is to be considered a periodontal pathogen. T. forsythia has been detected in periodontal health and disease, so could it be a pathogen? The species was not detected in many studies despite finding other putative pathogens, so could it be important in pathogenicity? The challenges of working with T. forsythia include its fastidious and anaerobic growth requirements for cultural detection. Thus, studies associating T. forsythia with periodontal and other oral infections have used noncultural approaches (immunoassays and DNA-based assays) in addition to cultural approaches. We feel …


The Functional Significance Of Multiple Pax7 Isoforms, Chantel L. Burchill Jan 2006

The Functional Significance Of Multiple Pax7 Isoforms, Chantel L. Burchill

Theses : Honours

The Pax7 gene is critical for specification of both neurons in the mid-brain and skeletal muscle satellite cells. Several alternate transcripts are transcribed from the single gene. Previous studies have shown that the resultant alternate Pax7 isoforms differ in the structure of their paired domain (a DNA-binding domain that influences target gene selection), yet the functional significance of each isoform for specification of neurogenic and myogenic cell types remains unknown. Although previous studies have identified the presence of multiple alternate Pax7 transcripts in both neurogenic and myogenic cell lines, more research is necessary to understand the functional significance of the …


The Amphibian Tree Of Life, Darrel R. Frost, Taran Grant, Julián Faivovich, Raoul H. Bain, Alexander Haas, Célio F.B. Haddad, Rafael O. De Sá Jan 2006

The Amphibian Tree Of Life, Darrel R. Frost, Taran Grant, Julián Faivovich, Raoul H. Bain, Alexander Haas, Célio F.B. Haddad, Rafael O. De Sá

Biology Faculty Publications

The evidentiary basis of the currently accepted classification of living amphibians is discussed and shown not to warrant the degree of authority conferred on it by use and tradition. A new taxonomy of living amphibians is proposed to correct the deficiencies of the old one. This new taxonomy is based on the largest phylogenetic analysis of living Amphibia so far accomplished. We combined the comparative anatomical character evidence of Haas (2003) with DNA sequences from the mitochondrial transcription unit H1 (12S and 16S ribosomal RNA and tRNAValine genes, ø 2,400 bp of mitochondrial sequences) and the nuclear genes histone H3, …


Tick Pheromones And Their Use In Tick Control, Daniel E. Sonenshine Jan 2006

Tick Pheromones And Their Use In Tick Control, Daniel E. Sonenshine

Biological Sciences Faculty Publications

Tick pheromones that regulate assembly, attraction/aggregation/attachment, and mating behavior have been described. Most of the compounds regulating these behaviors are purines, substituted phenols, or cholesteryl esters. Other pheromonal compounds include organic acids, hematin, or ecdysteroids. Novel devices have been developed that combine the specific compounds comprising these pheromones with an acaricide. When applied to tick-infested vegetation or directly to the body surfaces of livestock or companion animals, these devices are effective for tick control. This review summarizes the current state of knowledge of tick pheromones. In addition, this review also presents examples illustrating how devices using tick pheromones can offer …


Chironomid Hemoglobin Genetic Diversity As An Indicator Of The New Jersey Hackensack Meadowlands Wetland Health, Lene Marie De Coursin Jacobs Jan 2006

Chironomid Hemoglobin Genetic Diversity As An Indicator Of The New Jersey Hackensack Meadowlands Wetland Health, Lene Marie De Coursin Jacobs

Seton Hall University Dissertations and Theses (ETDs)

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Bayesian Analysis Of Cell-Cycle Gene Expression Data, Chuan Zhou, Jon Wakefield, Linda Breeden Dec 2005

Bayesian Analysis Of Cell-Cycle Gene Expression Data, Chuan Zhou, Jon Wakefield, Linda Breeden

UW Biostatistics Working Paper Series

The study of the cell-cycle is important in order to aid in our understanding of the basic mechanisms of life, yet progress has been slow due to the complexity of the process and our lack of ability to study it at high resolution. Recent advances in microarray technology have enabled scientists to study the gene expression at the genome-scale with a manageable cost, and there has been an increasing effort to identify cell-cycle regulated genes. In this chapter, we discuss the analysis of cell-cycle gene expression data, focusing on a model-based Bayesian approaches. The majority of the models we describe …


The Relationship Between Frq-Protein Stability And Temperature Compensation In The Neurospora Circadian Clock, Peter Ruoff, Jennifer J. Loros, Jay C. Dunlap Dec 2005

The Relationship Between Frq-Protein Stability And Temperature Compensation In The Neurospora Circadian Clock, Peter Ruoff, Jennifer J. Loros, Jay C. Dunlap

Dartmouth Scholarship

Temperature compensation is an important property of all biological clocks. In Neurospora crassa, negative-feedback regulation on the frequency (frq) gene's transcription by the FRQ protein plays a central role in the organism's circadian pacemaker. Earlier model calculations predicted that the stability of FRQ should determine the period length of Neurospora's circadian rhythm as well as the rhythm's temperature compensation. Here, we report experimental FRQ protein stabilities in frq mutants at 20 degrees C and 25 degrees C, and estimates of overall activation energies for mutant FRQ protein degradation. The results are consistent with earlier model predictions, i.e., temperature compensation of …


The Role Of An Explicit Causal Framework In Affected Sib Pair Designs With Covariates , Constantine E. Frangakis, Fan Li, Betty Q. Doan Dec 2005

The Role Of An Explicit Causal Framework In Affected Sib Pair Designs With Covariates , Constantine E. Frangakis, Fan Li, Betty Q. Doan

Johns Hopkins University, Dept. of Biostatistics Working Papers

The affected sib/relative pair (ASP/ARP) design is often used with covariates to find genes that can cause a disease in pathways other than through those covariates. However, such "covariates" can themselves have genetic determinants, and the validity of existing methods has so far only been argued under implicit assumptions. We propose an explicit causal formulation of the problem using potential outcomes and principal stratification. The general role of this formulation is to identify and separate the meaning of the different assumptions that can provide valid causal inference in linkage analysis. This separation helps to (a) develop better methods under explicit …


[Accepted Article Manuscript Version (Postprint)] Identification And Functional Characterization Of Arabidopsis Peroxin4 And The Interacting Protein Peroxin22, Bethany Zolman, Melanie Monroe-Augustus, Illeana Silva, Bonnie Bartel Dec 2005

[Accepted Article Manuscript Version (Postprint)] Identification And Functional Characterization Of Arabidopsis Peroxin4 And The Interacting Protein Peroxin22, Bethany Zolman, Melanie Monroe-Augustus, Illeana Silva, Bonnie Bartel

Biology Department Faculty Works

Peroxins are genetically defined as proteins necessary for peroxisome biogenesis. By screening for reduced response to indole-3-butyric acid, which is metabolized to active auxin in peroxisomes, we isolated an Arabidopsis thaliana peroxin4 (pex4) mutant. This mutant displays sucrose-dependent seedling development and reduced lateral root production, characteristics of plant peroxisome malfunction. We used yeast two-hybrid analysis to determine that PEX4, an apparent ubiquitinconjugating enzyme, interacts with a previously unidentified Arabidopsis protein, PEX22. A pex4 pex22 double mutant enhanced pex4 defects, confirming that PEX22 is a peroxin. Expression of both Arabidopsis genes together complemented yeast pex4 or pex22 mutant defects, whereas expression …


Bayer Ag V. Housey Pharmaceuticals: Protection For Biotechnological Research Tools Under Section 271(G) Found Wanting, Matthew Barthalow Dec 2005

Bayer Ag V. Housey Pharmaceuticals: Protection For Biotechnological Research Tools Under Section 271(G) Found Wanting, Matthew Barthalow

The University of New Hampshire Law Review

[Excerpt] "Research tools, a subset of biotechnological inventions protected by process patents, are “tools that scientists use in the laboratory, including cell lines, monoclonal antibodies, reagents, animal models, growth factors, combinatorial chemistry and DNA libraries, clones and cloning tools (such as PCR), methods, laboratory equipment and machines.” Many companies base their business models on the ability to find pharmaceutical products using their proprietary drug discovery research tools. Research tools used for drug discovery ‘include bioinformatic methods for identifying the interaction of certain proteins and their association with disease, methods for confirming protein targets, screening assays to identify molecules active against …


Community Analysis Of A Mercury Hot Spring Supports Occurrence Of Domain-Specific Forms Of Mercuric Reductase, Jessica Simbahan, Elizabeth Kurth, James Schelert, Amanda Dillman, Estuko N. Moriyama, Stevan Jovanovich, Paul H. Blum Dec 2005

Community Analysis Of A Mercury Hot Spring Supports Occurrence Of Domain-Specific Forms Of Mercuric Reductase, Jessica Simbahan, Elizabeth Kurth, James Schelert, Amanda Dillman, Estuko N. Moriyama, Stevan Jovanovich, Paul H. Blum

Papers in Genetics

Mercury is a redox-active heavy metal that reacts with active thiols and depletes cellular antioxidants. Active resistance to the mercuric ion is a widely distributed trait among bacteria and results from the action of mercuric reductase (MerA). Protein phylogenetic analysis of MerA in bacteria indicated the occurrence of a second distinctive form of MerA among the archaea, which lacked an N-terminal metal recruitment domain and a C-terminal active tyrosine. To assess the distribution of the forms of MerA in an interacting community comprising members of both prokaryotic domains, studies were conducted at a naturally occurring mercuryrich geothermal environment. Geochemical analyses …


Genetic And Molecular Analysis Of Phytochromes From The Filamentous Fungus Neurospora Crassa, Allan C. Froehlich, Bosl Noh, Richard D. Vierstra, Jennifer Loros, Jay C. Dunlap Dec 2005

Genetic And Molecular Analysis Of Phytochromes From The Filamentous Fungus Neurospora Crassa, Allan C. Froehlich, Bosl Noh, Richard D. Vierstra, Jennifer Loros, Jay C. Dunlap

Dartmouth Scholarship

Phytochromes (Phys) comprise a superfamily of red-/far-red-light-sensing proteins. Whereas higher-plant Phys that control numerous growth and developmental processes have been well described, the biochemical characteristics and functions of the microbial forms are largely unknown. Here, we describe analyses of the expression, regulation, and activities of two Phys in the filamentous fungus Neurospora crassa. In addition to containing the signature N-terminal domain predicted to covalently associate with a bilin chromophore, PHY-1 and PHY-2 contain C-terminal histidine kinase and response regulator motifs, implying that they function as hybrid two-component sensor kinases activated by light. A bacterially expressed N-terminal fragment of PHY-2 covalently …


Optimal Feature Selection For Nearest Centroid Classifiers, With Applications To Gene Expression Microarrays, Alan R. Dabney, John D. Storey Nov 2005

Optimal Feature Selection For Nearest Centroid Classifiers, With Applications To Gene Expression Microarrays, Alan R. Dabney, John D. Storey

UW Biostatistics Working Paper Series

Nearest centroid classifiers have recently been successfully employed in high-dimensional applications. A necessary step when building a classifier for high-dimensional data is feature selection. Feature selection is typically carried out by computing univariate statistics for each feature individually, without consideration for how a subset of features performs as a whole. For subsets of a given size, we characterize the optimal choice of features, corresponding to those yielding the smallest misclassification rate. Furthermore, we propose an algorithm for estimating this optimal subset in practice. Finally, we investigate the applicability of shrinkage ideas to nearest centroid classifiers. We use gene-expression microarrays for …


A New Approach To Intensity-Dependent Normalization Of Two-Channel Microarrays, Alan R. Dabney, John D. Storey Nov 2005

A New Approach To Intensity-Dependent Normalization Of Two-Channel Microarrays, Alan R. Dabney, John D. Storey

UW Biostatistics Working Paper Series

A two-channel microarray measures the relative expression levels of thousands of genes from a pair of biological samples. In order to reliably compare gene expression levels between and within arrays, it is necessary to remove systematic errors that distort the biological signal of interest. The standard for accomplishing this is smoothing "MA-plots" to remove intensity-dependent dye bias and array-specific effects. However, MA methods require strong assumptions. We review these assumptions and derive several practical scenarios in which they fail. The "dye-swap" normalization method has been much less frequently used because it requires two arrays per pair of samples. We show …


Principal Component Analysis For Predicting Transcription-Factor Binding Motifs From Array-Derived Data, Yunlong Liu, Matthew P Vincenti, Hiroki Yokota Nov 2005

Principal Component Analysis For Predicting Transcription-Factor Binding Motifs From Array-Derived Data, Yunlong Liu, Matthew P Vincenti, Hiroki Yokota

Dartmouth Scholarship

The responses to interleukin 1 (IL-1) in human chondrocytes constitute a complex regulatory mechanism, where multiple transcription factors interact combinatorially to transcription-factor binding motifs (TFBMs). In order to select a critical set of TFBMs from genomic DNA information and an array-derived data, an efficient algorithm to solve a combinatorial optimization problem is required. Although computational approaches based on evolutionary algorithms are commonly employed, an analytical algorithm would be useful to predict TFBMs at nearly no computational cost and evaluate varying modelling conditions. Singular value decomposition (SVD) is a powerful method to derive primary components of a given matrix. Applying SVD …