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Full-Text Articles in Life Sciences

Micrornas Reveal The Interrelationships Of Hagfish, Lampreys, And Gnathostomes And The Nature Of The Ancestral Vertebrate, Alysha M. Heimberg, Richard Cowper-Sal{Middle Dot}Lari, Marie Semon, Philip C. J. Donoghue, Kevin J. Peterson Nov 2010

Micrornas Reveal The Interrelationships Of Hagfish, Lampreys, And Gnathostomes And The Nature Of The Ancestral Vertebrate, Alysha M. Heimberg, Richard Cowper-Sal{Middle Dot}Lari, Marie Semon, Philip C. J. Donoghue, Kevin J. Peterson

Dartmouth Scholarship

Hagfish and lampreys are the only living representatives of the jawless vertebrates (agnathans), and compared with jawed vertebrates (gnathostomes), they provide insight into the embryology, genomics, and body plan of the ancestral vertebrate. However, this insight has been obscured by controversy over their interrelationships. Morphological cladistic analyses have identified lampreys and gnathostomes as closest relatives, whereas molecular phylogenetic studies recover a monophyletic Cyclostomata (hagfish and lampreys as closest relatives). Here, we show through deep sequencing of small RNA libraries, coupled with genomic surveys, that Cyclostomata is monophyletic: hagfish and lampreys share 4 unique microRNA families, 15 unique paralogues of more …


The Armadillo Repeat Protein Pf16 Is Essential For Flagellar Structure And Function In Plasmodium Male Gametes, Ursula Straschil, Arthur M. Talman, David J. P. Ferguson, Karen A. Bunting, Zhengyao Xu, Elizabeth Bailes, Robert E. Sinden, Anthony A. Holder, Elizabeth F. Smith Sep 2010

The Armadillo Repeat Protein Pf16 Is Essential For Flagellar Structure And Function In Plasmodium Male Gametes, Ursula Straschil, Arthur M. Talman, David J. P. Ferguson, Karen A. Bunting, Zhengyao Xu, Elizabeth Bailes, Robert E. Sinden, Anthony A. Holder, Elizabeth F. Smith

Dartmouth Scholarship

Malaria, caused by the apicomplexan parasite Plasmodium, threatens 40% of the world's population. Transmission between vertebrate and insect hosts depends on the sexual stages of the life-cycle. The male gamete of Plasmodium parasite is the only developmental stage that possesses a flagellum. Very little is known about the identity or function of proteins in the parasite's flagellar biology. Here, we characterise a Plasmodium PF16 homologue using reverse genetics in the mouse malaria parasite Plasmodium berghei. PF16 is a conserved Armadillo-repeat protein that regulates flagellar structure and motility in organisms as diverse as green algae and mice. We show that …


Invasive Predators Deplete Genetic Diversity Of Island Lizards, Amandine Gasc, M. C. Duryea, Robert M. Cox, Andrew Kern, Ryan Calsbeek Aug 2010

Invasive Predators Deplete Genetic Diversity Of Island Lizards, Amandine Gasc, M. C. Duryea, Robert M. Cox, Andrew Kern, Ryan Calsbeek

Dartmouth Scholarship

Invasive species can dramatically impact natural populations, especially those living on islands. Though numerous examples illustrate the ecological impact of invasive predators, no study has examined the genetic consequences for native populations subject to invasion. Here we capitalize on a natural experiment in which a long-term study of the brown anole lizard (Anolis sagrei) was interrupted by rat invasion. An island population that was devastated by rats recovered numerically following rat extermination. However, population genetic analyses at six microsatellite loci suggested a possible loss of genetic diversity due to invasion when compared to an uninvaded island studied over …


A Kinesin Motor In A Force-Producing Conformation, Elisabeth Heuston, C. Eric Bronner, F Jon Kull, Sharyn A. Endow Jul 2010

A Kinesin Motor In A Force-Producing Conformation, Elisabeth Heuston, C. Eric Bronner, F Jon Kull, Sharyn A. Endow

Dartmouth Scholarship

Kinesin motors hydrolyze ATP to produce force and move along microtubules, converting chemical energy into work by a mechanism that is only poorly understood. Key transitions and intermediate states in the process are still structurally uncharacterized, and remain outstanding questions in the field. Perturbing the motor by introducing point mutations could stabilize transitional or unstable states, providing critical information about these rarer states.


Temporal Regulation Of The Muscle Gene Cascade By Macho1 And Tbx6 Transcription Factors In Ciona Intestinalis, Jamie E. Kugler, Stefan Gazdoiu, Izumi Oda-Ishii, Yale J. Passamaneck, Albert J. Erives, Anna Di Gregorio Apr 2010

Temporal Regulation Of The Muscle Gene Cascade By Macho1 And Tbx6 Transcription Factors In Ciona Intestinalis, Jamie E. Kugler, Stefan Gazdoiu, Izumi Oda-Ishii, Yale J. Passamaneck, Albert J. Erives, Anna Di Gregorio

Dartmouth Scholarship

For over a century, muscle formation in the ascidian embryo has been representative of 'mosaic' development. The molecular basis of muscle-fate predetermination has been partly elucidated with the discovery of Macho1, a maternal zinc-finger transcription factor necessary and sufficient for primary muscle development, and of its transcriptional intermediaries Tbx6b and Tbx6c. However, the molecular mechanisms by which the maternal information is decoded by cis-regulatory modules (CRMs) associated with muscle transcription factor and structural genes, and the ways by which a seamless transition from maternal to zygotic transcription is ensured, are still mostly unclear. By combining misexpression assays with CRM analyses, …


Pcdp1 Is A Central Apparatus Protein That Binds Ca2+-Calmodulin And Regulates Ciliary Motility, Christen G. Dipetrillo, Elizabeth F. Smith Apr 2010

Pcdp1 Is A Central Apparatus Protein That Binds Ca2+-Calmodulin And Regulates Ciliary Motility, Christen G. Dipetrillo, Elizabeth F. Smith

Dartmouth Scholarship

For all motile eukaryotic cilia and flagella, beating is regulated by changes in intraciliary calcium concentration. Although the mechanism for calcium regulation is not understood, numerous studies have shown that calmodulin (CaM) is a key axonemal calcium sensor. Using anti-CaM antibodies and Chlamydomonas reinhardtii axonemal extracts, we precipitated a complex that includes four polypeptides and that specifically interacts with CaM in high [Ca2+]. One of the complex members, FAP221, is an orthologue of mammalian Pcdp1 (primary ciliary dyskinesia protein 1). Both FAP221 and mammalian Pcdp1 specifically bind CaM in high [Ca2+]. Reduced expression of Pcdp1 complex …


Role Of Flgt In Anchoring The Flagellum Of Vibrio Cholerae, Raquel M. Martinez, Brooke A. Jude, Thomas J. Kirn, Karen Skorupski, Ronald K. Taylor Apr 2010

Role Of Flgt In Anchoring The Flagellum Of Vibrio Cholerae, Raquel M. Martinez, Brooke A. Jude, Thomas J. Kirn, Karen Skorupski, Ronald K. Taylor

Dartmouth Scholarship

Flagellar motility has long been regarded as an important virulence factor. In Vibrio cholerae, the single polar flagellum is essential for motility as well as for proper attachment and colonization. In this study, we demonstrate that the novel flagellar protein FlgT is involved in anchoring the flagellum to the V. cholerae cell. A screen for novel colonization factors by use of TnphoA mutagenesis identified flgT. An in-frame deletion of flgT established that FlgT is required for attachment, colonization, and motility. Transmission electron microscopy revealed that while the flgT mutant is capable of assembling a phenotypically normal flagellum, …


Magnesium Excretion In C. Elegans Requires The Activity Of The Gtl-2 Trpm Channel, Takayuki Teramoto, Laura A. Sternick, Eriko Kage-Nakadai, Shirine Sajjadi, Jakub Siembida, Shohei Mitani, Kouichi Iwasaki, Eric J. Lambie Mar 2010

Magnesium Excretion In C. Elegans Requires The Activity Of The Gtl-2 Trpm Channel, Takayuki Teramoto, Laura A. Sternick, Eriko Kage-Nakadai, Shirine Sajjadi, Jakub Siembida, Shohei Mitani, Kouichi Iwasaki, Eric J. Lambie

Dartmouth Scholarship

Systemic magnesium homeostasis in mammals is primarily governed by the activities of the TRPM6 and TRPM7 cation channels, which mediate both uptake by the intestinal epithelial cells and reabsorption by the distal convoluted tubule cells in the kidney. In the nematode, C. elegans, intestinal magnesium uptake is dependent on the activities of the TRPM channel proteins, GON-2 and GTL-1. In this paper we provide evidence that another member of the TRPM protein family, GTL-2, acts within the C. elegans excretory cell to mediate the excretion of excess magnesium. Thus, the activity of GTL-2 balances the activities of the paralogous …


Il-28 Supplants Requirement For Treg Cells In Protein Σ1-Mediated Protection Against Murine Experimental Autoimmune Encephalomyelitis (Eae), Agnieszka Rynda, Massimo Maddaloni, Javier Ochoa-Repáraz, Gayle Callis, David W. Pascual Jan 2010

Il-28 Supplants Requirement For Treg Cells In Protein Σ1-Mediated Protection Against Murine Experimental Autoimmune Encephalomyelitis (Eae), Agnieszka Rynda, Massimo Maddaloni, Javier Ochoa-Repáraz, Gayle Callis, David W. Pascual

Dartmouth Scholarship

Conventional methods to induce tolerance in humans have met with limited success. Hence, efforts to redirect tolerogen uptake using reovirus adhesin, protein sigma 1 (pσ1), may circumvent these shortcomings based upon the recent finding that when reovirus pσ1 is engineered to deliver chicken ovalbumin (OVA) mucosally, tolerance is obtained, even with a single dose. To test whether single-dose tolerance can be induced to treat EAE, proteolipid protein (PLP130–151) was genetically fused to OVA to pσ1 (PLP:OVA-pσ1) and shown to significantly ameliorate EAE, suppressing proinflammatory cytokines by IL-10+ forkhead box P3 (FoxP3)+ CD25+CD4+ T …