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Full-Text Articles in Life Sciences

Septin Phosphorylation And Coiled-Coil Domains Function In Cell And Septin Ring Morphology In The Filamentous Fungus Ashbya Gossypii, Rebecca A. Meseroll, Patricia Occhipinti, Amy S. Gladfelter Nov 2012

Septin Phosphorylation And Coiled-Coil Domains Function In Cell And Septin Ring Morphology In The Filamentous Fungus Ashbya Gossypii, Rebecca A. Meseroll, Patricia Occhipinti, Amy S. Gladfelter

Dartmouth Scholarship

Septins are a class of GTP-binding proteins conserved throughout many eukaryotes. Individual septin subunits associate with one another and assemble into heteromeric complexes that form filaments and higher-order structures in vivo. The mechanisms underlying the assembly and maintenance of higher-order structures in cells remain poorly understood. Septins in several organisms have been shown to be phosphorylated, although precisely how septin phosphorylation may be contributing to the formation of high-order septin structures is unknown. Four of the five septins expressed in the filamentous fungus, Ashbya gossypii, are phosphorylated, and we demonstrate here the diverse roles of these phosphorylation sites …


Regulatory Elements Of Xenopus Col2a1 Drive Cartilaginous Gene Expression In Transgenic Frogs, Ryan R. Kerney, Brian K. Hall, James Hanken Oct 2012

Regulatory Elements Of Xenopus Col2a1 Drive Cartilaginous Gene Expression In Transgenic Frogs, Ryan R. Kerney, Brian K. Hall, James Hanken

Ryan Kerney

This study characterizes regulatory elements of collagen 2α1 (col2a1) in Xenopus that enable transgene expression in cartilage-forming chondrocytes. The reporters described in this study drive strong cartilage-specific gene expression, which will be a valuable tool for further investigations of Xenopus skeletal development. While endogenous col2a1 mRNA is expressed in many embryonic tissues, its expression becomes restricted to tadpole and adult chondrocytes. This chondrocyte-specific expression is recapitulated by col2a1 reporter constructs, which were tested through I-SceI meganuclease-mediated transgenesis. These constructs contain a portion of the Xenopus tropicalis col2a1 intron, which aligns to a cartilage-specific intronic enhancer that has been well characterized …


Using The Neandertal And Denisova Genetic Data To Understand The Common Mapt 17q21 Inversion In Modern Humans, Núria Setó-Salvia, Federico Sánchez-Quinto, Eudald Carbonell, Carlos Lorenzo, David Comas, Jordi Clarimón Sep 2012

Using The Neandertal And Denisova Genetic Data To Understand The Common Mapt 17q21 Inversion In Modern Humans, Núria Setó-Salvia, Federico Sánchez-Quinto, Eudald Carbonell, Carlos Lorenzo, David Comas, Jordi Clarimón

Human Biology Open Access Pre-Prints

The polymorphic inversion on 17q21, that includes the MAPT gene, represents a unique locus in the human genome characterized by a large region with strong linkage disequilibrium. Two distinct haplotypes, H1 and H2, exist in modern humans, and H1 has been unequivocally related to several neurodegenerative disorders. Recent data indicates that recurrent inversions of this genomic region have occurred through primate evolution, with the H2 haplotype being the ancestral state. Neandertals harbored the H1 haplotype, however until now no data was available for the Denisova hominin. Neandertals and Denisovans are sister groups that share a common ancestor with modern humans. …


Disparities In Allele Frequencies And Population Differentiation For 101 Disease-Associated Single Nucleotide Polymorphisms Between Puerto Ricans And Non-Hispanic Whites, Josiemer Mattei, Laurence D. Parnell, Chao-Qiang Lai, Bibiana Garcia-Bailo, Xian Adiconis, Jian Shen, Donna Arnett, Serkalem Demissie, Katherine L. Tucker, Jose M. Ordovas Aug 2012

Disparities In Allele Frequencies And Population Differentiation For 101 Disease-Associated Single Nucleotide Polymorphisms Between Puerto Ricans And Non-Hispanic Whites, Josiemer Mattei, Laurence D. Parnell, Chao-Qiang Lai, Bibiana Garcia-Bailo, Xian Adiconis, Jian Shen, Donna Arnett, Serkalem Demissie, Katherine L. Tucker, Jose M. Ordovas

Katherine L. Tucker

Background: Variations in gene allele frequencies can contribute to differences in the prevalence of some common complex diseases among populations. Natural selection modulates the balance in allele frequencies across populations. Population differentiation (FST) can evidence environmental selection pressures. Such genetic information is limited in Puerto Ricans, the second largest Hispanic ethnic group in the US, and a group with high prevalence of chronic disease. We determined allele frequencies and population differentiation for 101 single nucleotide polymorphisms (SNPs) in 30 genes involved in major metabolic and disease-relevant pathways in Puerto Ricans (n = 969, ages 45–75 years) and compared them to …


Farnesol And Cyclic Amp Signaling Effects On The Hypha-To-Yeast Transition In Candida Albicans, Allia K. Lindsay, Aurélie Deveau, Amy E. Piispanen, Deborah A. Hogan Aug 2012

Farnesol And Cyclic Amp Signaling Effects On The Hypha-To-Yeast Transition In Candida Albicans, Allia K. Lindsay, Aurélie Deveau, Amy E. Piispanen, Deborah A. Hogan

Dartmouth Scholarship

Candida albicans, a fungal pathogen of humans, regulates its morphology in response to many environmental cues and this morphological plasticity contributes to virulence. Farnesol, an autoregulatory molecule produced by C. albicans, inhibits the induction of hyphal growth by inhibiting adenylate cyclase (Cyr1). The role of farnesol and Cyr1 in controlling the maintenance of hyphal growth has been less clear. Here, we demonstrate that preformed hyphae transition to growth as yeast in response to farnesol and that strains with increased cyclic AMP (cAMP) signaling exhibit more resistance to farnesol. Exogenous farnesol did not induce the hypha-to-yeast transition in mutants …


Condensin Ii Promotes The Formation Of Chromosome Territories By Inducing Axial Compaction Of Polyploid Interphase Chromosomes, Christopher R. R. Bauer, Tom A. Hartl, Giovanni Bosco Aug 2012

Condensin Ii Promotes The Formation Of Chromosome Territories By Inducing Axial Compaction Of Polyploid Interphase Chromosomes, Christopher R. R. Bauer, Tom A. Hartl, Giovanni Bosco

Dartmouth Scholarship

The eukaryotic nucleus is both spatially and functionally partitioned. This organization contributes to the maintenance, expression, and transmission of genetic information. Though our ability to probe the physical structure of the genome within the nucleus has improved substantially in recent years, relatively little is known about the factors that regulate its organization or the mechanisms through which specific organizational states are achieved. Here, we show that Drosophila melanogaster Condensin II induces axial compaction of interphase chromosomes, globally disrupts interchromosomal interactions, and promotes the dispersal of peri-centric heterochromatin. These Condensin II activities compartmentalize the nucleus into discrete chromosome territories and indicate …


The Effects Of Cytokinin On The Transcriptional Regulation Of Pin Expression In Arabidopsis Thaliana, Elizabeth Burgess Jul 2012

The Effects Of Cytokinin On The Transcriptional Regulation Of Pin Expression In Arabidopsis Thaliana, Elizabeth Burgess

Honors Theses and Capstones

The processes of cell division and differentiation are critical to the development of any multicellular organism. During the formation of plant roots these processes take place at a region of the root tip called the meristem. Cytokinin and auxin are two plant growth hormones that influence this process. Although these two growth hormones are both necessary they also appear in many ways to have an antagonistic relationship. As meristematic root cells undergo differentiation they cease dividing. It has been proposed that the size of the root meristem and thus the overall rate of root growth are determined by the balance …


Two Boundaries Separate Borrelia Burgdorferi Populations In North America, Gabriele Margos, Jean I. Tsao, Santiago Castillo-Ramirez, Yvette A. Girard, Anne G. Hoen Jun 2012

Two Boundaries Separate Borrelia Burgdorferi Populations In North America, Gabriele Margos, Jean I. Tsao, Santiago Castillo-Ramirez, Yvette A. Girard, Anne G. Hoen

Dartmouth Scholarship

Understanding the spread of infectious diseases is crucial for implementing effective control measures. For this, it is important to obtain information on the contemporary population structure of a disease agent and to infer the evolutionary processes that may have shaped it. Here, we investigate on a continental scale the population structure of Borrelia burgdorferi, the causative agent of Lyme borreliosis (LB), a tick-borne disease, in North America. We test the hypothesis that the observed d population structure is congruent with recent population expansions and that these were preceded by bottlenecks mostly likely caused by the near extirpation in the 1900s …


Dna Methylation Arrays As Surrogate Measures Of Cell Mixture Distribution, Eugene Houseman, William P. Accomando, Devin C. Koestler, Brock C. Christensen, Carmen J. Marsit May 2012

Dna Methylation Arrays As Surrogate Measures Of Cell Mixture Distribution, Eugene Houseman, William P. Accomando, Devin C. Koestler, Brock C. Christensen, Carmen J. Marsit

Dartmouth Scholarship

There has been a long-standing need in biomedical research for a method that quantifies the normally mixed composition of leukocytes beyond what is possible by simple histological or flow cytometric assessments. The latter is restricted by the labile nature of protein epitopes, requirements for cell processing, and timely cell analysis. In a diverse array of diseases and following numerous immune-toxic exposures, leukocyte composition will critically inform the underlying immuno-biology to most chronic medical conditions. Emerging research demonstrates that DNA methylation is responsible for cellular differentiation, and when measured in whole peripheral blood, serves to distinguish cancer cases from controls.


The Tlo Proteins Are Stoichiometric Components Of Candida Albicans Mediator Anchored Via The Med3 Subunit, Anda Zhang, Kostadin O. Petrov, Emily R. Hyun, Zhongle Liu, Scott A. Gerber, Lawrence C. Myers May 2012

The Tlo Proteins Are Stoichiometric Components Of Candida Albicans Mediator Anchored Via The Med3 Subunit, Anda Zhang, Kostadin O. Petrov, Emily R. Hyun, Zhongle Liu, Scott A. Gerber, Lawrence C. Myers

Dartmouth Scholarship

The amplification of the TLO (for telomere-associated) genes in Candida albicans, compared to its less pathogenic, close relative Candida dubliniensis, suggests a role in virulence. Little, however, is known about the function of the Tlo proteins. We have purified the Mediator coactivator complex from C. albicans (caMediator) and found that Tlo proteins are a stoichiometric component of caMediator. Many members of the Tlo family are expressed, and each is a unique member of caMediator. Protein expression analysis of individual Tlo proteins, as well as the purification of tagged Tlo proteins, demonstrate that there is a large free population of Tlo …


Dialogues, Dilemmas, And Disclosures: Genomic Research And Incidental Findings, Lynn W. Bush, Karen H. Rothenberg Mar 2012

Dialogues, Dilemmas, And Disclosures: Genomic Research And Incidental Findings, Lynn W. Bush, Karen H. Rothenberg

Faculty Scholarship

No abstract provided.


Genes And Plays: Bringing Elsi Issues To Life, Karen H. Rothenberg, Lynn W. Bush Feb 2012

Genes And Plays: Bringing Elsi Issues To Life, Karen H. Rothenberg, Lynn W. Bush

Faculty Scholarship

Ethical complexities surround the promise of genomic technology and the power of genetic information as they alter conceptions of identity and dynamics within personal and professional relationships. Creative approaches such as dramatic vignettes offer a unique analytical stage for imagining the bioethical past and future. Dramatic narratives can bring to life images of differing perspectives and values when experiencing innovations in medicine. Although the scientific landscape shifts, concerns expressed in theatre from 50 years ago parallel many contemporary ELSI (ethical, legal and social implications) issues, highlighting the ongoing struggle to appreciate the impact of emerging genetic technologies on relationships. To …


Heterogeneity In Mitochondrial Morphology And Membrane Potential Is Independent Of The Nuclear Division Cycle In Multinucleate Fungal Cells, John P. Gerstenberger, Patricia Occhipinti, Amy S. Gladfelter Jan 2012

Heterogeneity In Mitochondrial Morphology And Membrane Potential Is Independent Of The Nuclear Division Cycle In Multinucleate Fungal Cells, John P. Gerstenberger, Patricia Occhipinti, Amy S. Gladfelter

Dartmouth Scholarship

In the multinucleate filamentous fungus Ashbya gossypii, nuclei divide asynchronously in a common cytoplasm. We hypothesize that the division cycle machinery has a limited zone of influence in the cytoplasm to promote nuclear autonomy. Mitochondria in cultured mammalian cells undergo cell cycle-specific changes in morphology and membrane potential and therefore can serve as a reporter of the cell cycle state of the cytoplasm. To evaluate if the cell cycle state of nuclei in A. gossypii can influ


Genetics And Cancer, Sachin Puri Jan 2012

Genetics And Cancer, Sachin Puri

A with Honors Projects

Genes' effect in body and relationship with cancer. Role in cell cycle and angiogenesis.