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Biology Faculty Research

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Articles 271 - 300 of 396

Full-Text Articles in Biology

Characterization Of Γ-Butyrolactone Autoregulatory Signaling Gene Homologs In The Angucyclinone Polyketide Ws5995b Producer Streptomyces Acidiscabies, Frank G. Healy, Kevin P. Eaton, Prajit Limsirichai, Joel F. Aldrich, Alaina K. Plowman, Russell R. King Aug 2009

Characterization Of Γ-Butyrolactone Autoregulatory Signaling Gene Homologs In The Angucyclinone Polyketide Ws5995b Producer Streptomyces Acidiscabies, Frank G. Healy, Kevin P. Eaton, Prajit Limsirichai, Joel F. Aldrich, Alaina K. Plowman, Russell R. King

Biology Faculty Research

Organisms belonging to the genus Streptomyces produce numerous important secondary metabolites and undergo a sophisticated morphological differentiation program. In many instances these processes are under the control of gamma-butyrolactone (GBL) autoregulatory systems. Streptomyces acidiscabies strain 84.104 produces the secondary metabolite aromatic angucyclinone polyketide WS5995B. In order to explore the role of GBL regulatory circuitry in WS5995B production and morphogenesis in S. acidiscabies, a gene cluster encoding GBL autoregulatory signaling homologs was identified and characterized. Two GBL receptor homologs, sabR and sabS, were found flanking a GBL synthase homolog sabA. Strains carrying mutations in sabS produced elevated levels …


Drosophila Risc Component Vig And Its Homolog Vig2 Impact Heterochromatin Formation, Elena Gracheva, Monica Dus, Sarah C.R. Elgin Jul 2009

Drosophila Risc Component Vig And Its Homolog Vig2 Impact Heterochromatin Formation, Elena Gracheva, Monica Dus, Sarah C.R. Elgin

Biology Faculty Research

Heterochromatin formation plays an important role in gene regulation and the maintenance of genome integrity. Here we present results from a study of the D. melanogaster gene vig, encoding an RNAi complex component and its homolog vig2 (CG11844) that support their involvement in heterochromatin formation and/or maintenance. Protein null mutations vig(EP812) and vig2(PL470) act as modifiers of Position Effect Variegation (PEV). VIG and Vig2 are present in polytene chromosomes and partially overlap with HP1. Quantitative immunoblots show depletion of HP1 and HP2 (large isoform) in isolated nuclei from the vig(EP812) mutant. The vig2(PL470) mutant strain demonstrates a decreased level of …


Unlocking The Secrets Of The Genome, Susan Celniker, Laura Dillon, Mark Gerstein, Kristin Gunsalus, Steven Henikoff, Gary Karpen, Manolis Kellis, Eric Lai, Jason Lieb, David Macalpine, Gos Micklem, Fabio Piano, Michael Snyder, Lincoln Stein, Kevin White, Robert Waterston, Sarah C.R. Elgin Jun 2009

Unlocking The Secrets Of The Genome, Susan Celniker, Laura Dillon, Mark Gerstein, Kristin Gunsalus, Steven Henikoff, Gary Karpen, Manolis Kellis, Eric Lai, Jason Lieb, David Macalpine, Gos Micklem, Fabio Piano, Michael Snyder, Lincoln Stein, Kevin White, Robert Waterston, Sarah C.R. Elgin

Biology Faculty Research

Despite the successes of genomics, little is known about how genetic information produces complex organisms. A look at the crucial functional elements of fly and worm genomes could change that.


Guided Inquiry Lab Exercises In Development And Oxygen Consumption Using Zebrafish, Brian Bagatto Jun 2009

Guided Inquiry Lab Exercises In Development And Oxygen Consumption Using Zebrafish, Brian Bagatto

Biology Faculty Research

Zebrafish have become a model organism in many areas of research and are now being used with more frequency in the classroom to teach important biological concepts. The two guided inquiry exercises in this article are each aimed at a different level of instruction, but each can be modified to fit the needs of many high school or college-level courses. The "Zebrafish Development and Environment'' exercise teaches high school students about zebrafish development by presenting a series of embryos at different ages. Without access to visual references, students are asked to rank developing zebrafish by age and explain their choices. …


Effects Of Microzooplankton Growth And Trophic Interactions On Herbivory In Coastal And Offshore Environments, Matthew R. First, Harlan L. Miller Iii, Peter J. Lavrentyev, James L. Pinckney, Adrian B. Burd Mar 2009

Effects Of Microzooplankton Growth And Trophic Interactions On Herbivory In Coastal And Offshore Environments, Matthew R. First, Harlan L. Miller Iii, Peter J. Lavrentyev, James L. Pinckney, Adrian B. Burd

Biology Faculty Research

We performed serial dilution experiments to estimate rates of gross phytoplankton growth (L) and grazing mortality (m) in both eutrophic (Corpus Christi Bay, Texas, USA) and oligotrophic (offshore Gulf of Mexico) waters. Two parallel experiments were performed in both environments, with seawater pre-screened through 153 or 25 Inn mesh to observe the responses of microzooplankton (MZP) to dilution treatments. MZP biomass changed over the duration of the experimental incubations; in several treatments, MZP net growth rates were >1 d(-1). Patterns of growth varied between dilutions and initial screening size. In the eutrophic system, the ratio of phytoplankton grazing mortality rate …


Avian Incubation Inhibits Growth And Diversification Of Bacterial Assemblages On Eggs, Matthew D. Shawkey, Mary K. Firestone, Eoin L. Brodie, Steven R. Beissinger Feb 2009

Avian Incubation Inhibits Growth And Diversification Of Bacterial Assemblages On Eggs, Matthew D. Shawkey, Mary K. Firestone, Eoin L. Brodie, Steven R. Beissinger

Biology Faculty Research

Microbial infection is a critical source of mortality for early life stages of oviparous vertebrates, but parental defenses against infection are less well known. Avian incubation has been hypothesized to reduce the risk of trans-shell infection by limiting microbial growth of pathogenic bacteria on eggshells, while enhancing growth of commensal or beneficial bacteria that inhibit or competitively exclude pathogens. We tested this hypothesis by comparing bacterial assemblages on naturally incubated and experimentally unincubated eggs at laying and late incubation using a universal 16S rRNA microarray containing probes for over 8000 bacterial taxa. Before treatment, bacterial assemblages on individual eggs from …


A Lot About A Little Dot - Lessons Learned From Drosophila Melanogaster Chromosome 4, Nicole Riddle, Christopher Shaffer, Sarah C.R. Elgin Feb 2009

A Lot About A Little Dot - Lessons Learned From Drosophila Melanogaster Chromosome 4, Nicole Riddle, Christopher Shaffer, Sarah C.R. Elgin

Biology Faculty Research

The fourth chromosome of Drosophila melanogaster has a number of unique properties that make it a convenient model for the study of chromatin structure. Only 4.2 Mb overall, the 1.2 Mb distal arm of chromosome 4 seen in polytene chromosomes combines characteristics of heterochromatin and euchromatin. This domain has a repeat density of ~35%, comparable to some pericentric chromosome regions, while maintaining a gene density similar to that of the other euchromatic chromosome arms. Studies of position-effect variegation have revealed that heterochromatic and euchromatic domains are interspersed on chromosome 4, and both cytological and biochemical studies have demonstrated that chromosome …


Which Sry Locus Is The Hypertensive Y Chromosome Locus?, Monte E. Turner, Joel Farkas, Jeff Dunmire, Daniel Ely, Amy Milsted Feb 2009

Which Sry Locus Is The Hypertensive Y Chromosome Locus?, Monte E. Turner, Joel Farkas, Jeff Dunmire, Daniel Ely, Amy Milsted

Biology Faculty Research

The Y chromosome of the spontaneously hypertensive rat (SHR) contains a genetic component that raises blood pressure compared with the Wistar-Kyoto (WKY) Y chromosome. This research tests the Sry gene complex as the hypertensive component of the SHR Y chromosome. The Sry loci were sequenced in 1 strain with a hypertensive Y chromosome (SHR/Akr) and 2 strains with a normotensive Y chromosome (SHR/Crl and WKY/Akr). Both SHR strains have 7 Sry loci, whereas the WKY strain has 6. The 6 loci in common between SHR and WKY strains were identical in the sequence compared (coding region, 392-bp 5' prime flanking, …


Can Males Successfully Invade Hermaphroditic Populations Of Clam Shrimp (Eulimnadia Texana)?, Stephen C. Weeks Jan 2009

Can Males Successfully Invade Hermaphroditic Populations Of Clam Shrimp (Eulimnadia Texana)?, Stephen C. Weeks

Biology Faculty Research

Androdioecy (mixtures of males and hermaphrodites) is distinguished by its rarity, being found in only similar to 40 animal species. Many of these species are clam shrimp in the genus Eulimnadia. A metapopulation model for the maintenance of androdioecy is tested herein by examining male success in aquaria with a single male-producing hermaphrodite introduced into an otherwise all-hermaphrodite population. This migration experiment did allow males to persist in these populations for seven generations, although at levels below those found in other populations of these shrimp. These results suggest that the maintenance of androdioecy via 'reproductive assurance' is unlikely by way …


Basal Autophagy Induction Without Amp-Activated Protein Kinase Under Low Glucose Conditions, Tyisha Williams, L. J. Forsberg, B. Viollet, J. E. Brenman Jan 2009

Basal Autophagy Induction Without Amp-Activated Protein Kinase Under Low Glucose Conditions, Tyisha Williams, L. J. Forsberg, B. Viollet, J. E. Brenman

Biology Faculty Research

When ATP levels in a cell decrease, various homeostatic intracellular mechanisms initiate attempts to restore ATP levels. As a prominent energy sensor, AMP-activated protein kinase (AMPK) represents one molecular gauge that links energy levels to regulation of anabolic and catabolic processes to restore energy balance. Although pharmacological studies have suggested that an AMPK activator, AIC AR (5-aminoimidazole-4-carboxamide ribonucleoside) may link AMPK activation to autophagy, a process that can provide short-term energy within the cell, AICAR can have AMPK-independent effects. Therefore, using a genetic-based approach we investigated the role of AMPK in cellular energy balance. We demonstrate that genetically altered cells, …


The Round-Eared Sengi And The Evolution Of Social Monogamy: Factors That Constrain Males To Live With A Single Female, M. Schubert, N. Pillay, David O. Ribble, C. Schradin Jan 2009

The Round-Eared Sengi And The Evolution Of Social Monogamy: Factors That Constrain Males To Live With A Single Female, M. Schubert, N. Pillay, David O. Ribble, C. Schradin

Biology Faculty Research

Animal dispersion in space and time results from environmental pressures, and affects the outcome of a species’ social organization. When females are solitary, males may either roam or be pair-living. We studied possible environmental influences affecting the social organization of the round-eared sengi (Macroscelides proboscideus) in a semi-desert in South Africa, using trapping and radio-tracking across 2.5 yr. Adult sex ratios did not deviate from 1:1 and we found no indication of sexual dimorphism in body mass. Females maintained exclusive areas, which had little overlap (


Small Rna-Directed Heterochromatin Formation In The Context Of Development: What Flies Might Learn From Fission Yeast, Kathryn Huisinga, Sarah C.R. Elgin Jan 2009

Small Rna-Directed Heterochromatin Formation In The Context Of Development: What Flies Might Learn From Fission Yeast, Kathryn Huisinga, Sarah C.R. Elgin

Biology Faculty Research

A link between the RNAi system and heterochromatin formation has been established in several model organisms including Schizosaccharomyces pombe and Arabidopsis thaliana. However, the data to support a role for small RNAs and the associated machinery in transcriptional gene silencing in animal systems is more tenuous. Using the S. pombe system as a model, we analyze the role of small RNA pathway components and associated small RNAs in regulating transposable elements and potentially directing heterochromatin formation at these elements in Drosophila melanogaster.


Inbreeding Effects On Sperm Production In Clam Shrimp (Eulimnadia Texana), Stephen C. Weeks, Sadie K. Reed, Donald W. Ott, Franca Scanabissi Jan 2009

Inbreeding Effects On Sperm Production In Clam Shrimp (Eulimnadia Texana), Stephen C. Weeks, Sadie K. Reed, Donald W. Ott, Franca Scanabissi

Biology Faculty Research

Hypothesis: Inbreeding depression is manifest in lower sperm production. Organism: Freshwater crustaceans (clam shrimp - Eulimnadia texana), from the southwestern United States, which have high levels of inbreeding. Methods: Comparisons of semi-thin sections of the male gonad among selfed and outcrossed siblings from four families. Results: There was a twofold reduction in sperm production in inbred relative to outcrossed males. Inbreeding depression in males was higher than previous estimates from hermaphrodites. Conclusions: Inbreeding markedly reduces sperm production. The observed low levels of sperm production can explain both the low average outcrossing rates as well as the variation in these rates …


Coiled-Coil-Mediated Dimerization Is Not Required For Myosin Vi To Stabilize Actin During Spermatid Individualization In Drosophila Melanogaster, Tatsuhiko Nogushi, Deborah J. Frank, Mamiko Isaji, Kathryn G. Miller Jan 2009

Coiled-Coil-Mediated Dimerization Is Not Required For Myosin Vi To Stabilize Actin During Spermatid Individualization In Drosophila Melanogaster, Tatsuhiko Nogushi, Deborah J. Frank, Mamiko Isaji, Kathryn G. Miller

Biology Faculty Research

Myosin VI is a pointed-end-directed actin motor that is thought to function as both a transporter of cargoes and an anchor, capable of binding cellular components to actin for long periods. Dimerization via a predicted coiled coil was hypothesized to regulate activity and motor properties. However, the importance of the coiled-coil sequence has not been tested in vivo. We used myosin VI's well-defined role in actin stabilization during Drosophila spermatid individualization to test the importance in vivo of the predicted coiled coil. If myosin VI functions as a dimer, a forced dimer should fully rescue myosin VI loss of function …


Estrogen Receptors In The Medial Amygdala Inhibit The Expression Of Male Prosocial Behavior, Bruce S. Cushing, Adam Perry, Sergei Musatov, Sonoko Ogawa Oct 2008

Estrogen Receptors In The Medial Amygdala Inhibit The Expression Of Male Prosocial Behavior, Bruce S. Cushing, Adam Perry, Sergei Musatov, Sonoko Ogawa

Biology Faculty Research

Studies using estrogen receptor alpha(ER) knock-out mice indicate that ER alpha masculinizes male behavior. Recent studies of ER alpha and male prosocial behavior have shown an inverse relationship between ER alpha expression in regions of the brain that regulate social behavior, including the medial amygdala (MeA), and the expression of male prosocial behavior. These studies have lead to the hypothesis that low levels of ER alpha are necessary to "permit" the expression of high levels of male prosocial behavior. To test this, viral vectors were used to enhance ER alpha in male prairie voles (Microtus ochrogaster), which display high levels …


Undergraduate Research. Genomics Education Partnership, D Lopatto, C Alvarez, D Barnard, C Chandrasekaran, H-M Chung, C Du, T Eckdahl, A Goodman, C Hauser, C Jones, O Kopp, G Kuleck, G Mcneil, R Morris, J Myka, A Nagengast, P Overvoorde, J Poet, K Reed, G Regisford, D Revie, A Rosenwald, K Saville, M Shaw, G Skuse, C Smith, M Smith, M Spratt, J Stamm, J Thompson, B Wilson, C Witkowski, J Youngblom, Wilson Leung, Christopher Shaffer, Jeremy Buhler, Elaine Mardis, Sarah C.R. Elgin Oct 2008

Undergraduate Research. Genomics Education Partnership, D Lopatto, C Alvarez, D Barnard, C Chandrasekaran, H-M Chung, C Du, T Eckdahl, A Goodman, C Hauser, C Jones, O Kopp, G Kuleck, G Mcneil, R Morris, J Myka, A Nagengast, P Overvoorde, J Poet, K Reed, G Regisford, D Revie, A Rosenwald, K Saville, M Shaw, G Skuse, C Smith, M Smith, M Spratt, J Stamm, J Thompson, B Wilson, C Witkowski, J Youngblom, Wilson Leung, Christopher Shaffer, Jeremy Buhler, Elaine Mardis, Sarah C.R. Elgin

Biology Faculty Research

The Genomics Education Partnership offers an inclusive model for undergraduate research experiences incorporated into the academic year science curriculum, with students pooling their work to contribute to international data bases.


Grazing And Virus-Induced Mortality Of Microbial Populations Before And During The Onset Of Annual Hypoxia In Lake Erie, Christopher J. Gobler, Timothy W. Davis, Sarah N. Deonarine, Matthew A. Saxton, Peter J. Lavrentyev, Frank J. Jochem May 2008

Grazing And Virus-Induced Mortality Of Microbial Populations Before And During The Onset Of Annual Hypoxia In Lake Erie, Christopher J. Gobler, Timothy W. Davis, Sarah N. Deonarine, Matthew A. Saxton, Peter J. Lavrentyev, Frank J. Jochem

Biology Faculty Research

Lake Erie is the most productive of the North American Great Lakes and experiences annual periods of hypolimnetic hypoxia with unknown consequences for the microbial food web. We established the abundances and mortality rates of microbes in Lake Erie during thermal stratification and determined how they varied with changes in bottom-water dissolved oxygen concentrations. The microbial plankton community (heterotrophic bacteria, Cyanobacteria, eukaryotic phytoplankton, nanozooplankton, microzooplankton) was quantified in surface and bottom waters along with measurements of herbivory and bacterivory rates on eukaryotic and prokaryotic picoplankton and rates of viral lysis of bacteria. High rates of grazing mortality of prokaryotic picoplankton …


Sticky Gecko Feet: The Role Of Temperature And Humidity, Peter H. Niewiarowski, Stephanie Lopez, Liehui Ge, Emily Hagan, Ali Dhinojwala May 2008

Sticky Gecko Feet: The Role Of Temperature And Humidity, Peter H. Niewiarowski, Stephanie Lopez, Liehui Ge, Emily Hagan, Ali Dhinojwala

Biology Faculty Research

Gecko adhesion is expected to be temperature insensitive over the range of temperatures typically experienced by geckos. Previous work is limited and equivocal on whether this expectation holds. We tested the temperature dependence of adhesion in Tokay and Day geckos and found that clinging ability at 12 degrees C was nearly double the clinging ability at 32 degrees C. However, rather than confirming a simple temperature effect, our data reveal a complex interaction between temperature and humidity that can drive differences in adhesion by as much as two-fold. Our findings have important implications for inferences about the mechanisms underlying the …


Sex-Role Reversal In Song? Females Sing More Frequently Than Males In The Streak-Backed Oriole, J. J. Price, L. Yunes-Jimenez, M. Osorio-Beristain, K. E. Omland, Troy G. Murphy May 2008

Sex-Role Reversal In Song? Females Sing More Frequently Than Males In The Streak-Backed Oriole, J. J. Price, L. Yunes-Jimenez, M. Osorio-Beristain, K. E. Omland, Troy G. Murphy

Biology Faculty Research

Birds in which both sexes produce complex song are more common in the tropics than in the temperate north, where typically only males sing. Yet surprisingly little is known about female song characteristics in most tropical species. Here we present a comparison of female and male singing behaviors in the Streak-backed Oriole (Icterus pustulatus), a tropical songbird in which both sexes perform solo songs. Females sing much more frequently than males and produce songs with similar acoustic complexity. Rates of singing by both sexes were higher during breeding than postbreeding while the rates of most other vocalizations did …


Chromosomes And Expression Mechanisms: Bringing Together The Roles Of Dna, Rna And Proteins, Moshe Yaniv, Sarah C.R. Elgin Apr 2008

Chromosomes And Expression Mechanisms: Bringing Together The Roles Of Dna, Rna And Proteins, Moshe Yaniv, Sarah C.R. Elgin

Biology Faculty Research

No abstract provided.


A New Species Of Giant Sengi Or Elephant-Shrew (Genus Rhynchocyon) Highlights The Exceptional Biodiversity Of The Udzungwa Mountains Of Tanzania, F Rovero, G B. Rathbun, A Perkin, T Jones, David O. Ribble, C Leonard, R R. Mwakisoma, N Doggart Feb 2008

A New Species Of Giant Sengi Or Elephant-Shrew (Genus Rhynchocyon) Highlights The Exceptional Biodiversity Of The Udzungwa Mountains Of Tanzania, F Rovero, G B. Rathbun, A Perkin, T Jones, David O. Ribble, C Leonard, R R. Mwakisoma, N Doggart

Biology Faculty Research

A new species of sengi, or elephant-shrew, is described. It was discovered in the northern Udzungwa Mountains of Tanzania in 2005. Sengis (Order Macroscelidea, super-cohort Afrotheria) include four genera and 15 species of mammals that are endemic to Africa. This discovery is a significant contribution to the systematics of this small order. Based on 49 camera trap images, 40 sightings and five voucher specimens, the new sengi is diurnal and distinguished from the other three species of Rhynchocyon by a grizzled grey face, pale yellow to cream chest and chin, orange-rufous sides, maroon back and jet-black lower rump and thighs. …


Lack Of Assortative Mating For Tail, Body Size, Or Condition In The Elaborate Monomorphic Turquoise-Browed Motmot (Eumomota Superciliosa), Troy G. Murphy Jan 2008

Lack Of Assortative Mating For Tail, Body Size, Or Condition In The Elaborate Monomorphic Turquoise-Browed Motmot (Eumomota Superciliosa), Troy G. Murphy

Biology Faculty Research

Elaborate male and female plumage can be maintained by mutual sexual selection and function as a mate-choice or status signal in both sexes. Both male and female Turquoise-browed Motmot (Eumomota superciliosa) have long tails that terminate in widened blue-and-black rackets that appear to hang, unattached, below the body of the bird. I tested whether mutual sexual selection maintains the Turquoise-browed Motmot’s elaborate tail plumage by testing the prediction that mating occurs in an assortative manner for tail plumage. I also tested whether assortative mating occurs for body size, a potential measure of dominance, and for phenotypic condition, a …


Display Of An Inedible Prop As A Signal Of Aggression? Adaptive Significance Of Leaf-Display By The Turquoise-Browed Motmot, Eumomota Superciliosa, Troy G. Murphy Jan 2008

Display Of An Inedible Prop As A Signal Of Aggression? Adaptive Significance Of Leaf-Display By The Turquoise-Browed Motmot, Eumomota Superciliosa, Troy G. Murphy

Biology Faculty Research

The incorporation of an inedible object (prop) into a behavioral display is rare among birds. Only four avian taxa have been reported to display with a prop, and in all studied species, prop use has been found to play a role in mate acquisition. However, little is known about the context and adaptive significance of prop use by the motmots. Both male and female motmots perform a leaf-display, whereby a leaf is held horizontally in the tip of the bill for an extended period. I collected observational data on leaf-display by the turquoise-browed motmots (Eumomota superciliosa) to investigate …


Effects Of Population Size And Density On Pollinator Visitation, Pollinator Behavior, And Pollen Tube Abundance In Lupinus Perennis, Christopher E. Bernhardt, Randall J. Mitchell, Helen J. Michaels Jan 2008

Effects Of Population Size And Density On Pollinator Visitation, Pollinator Behavior, And Pollen Tube Abundance In Lupinus Perennis, Christopher E. Bernhardt, Randall J. Mitchell, Helen J. Michaels

Biology Faculty Research

Both the number and the density of flowering plants in a population can be important determinants of pollinator abundance and behavior. We report the joint effects of population size and density on pollinator visitation and pollination success for Lupinus perennis (Fabaceae). Focusing on five pairs of populations, we matched one small population (125-800 flowering plants) with one distinctly larger population (1000-3000 flowering plants). In these pairs, population size did not affect pollinator communities or pollination success. All measures of pollination success increased significantly with density. Only bee behavior (number of flowers probed per inflorescence) exhibited a significant interaction of size …


The Sacred Emergence Of Nature, Ursula Goodenough, Terrence W. Deacon Jan 2008

The Sacred Emergence Of Nature, Ursula Goodenough, Terrence W. Deacon

Biology Faculty Research

No abstract provided.


Proper Cellular Reorganization During Drosophila Spermatid Individualization Depends On Actin Structures Composed Of Two Domains, Bundles And Meshwork, That Are Differentially Regulated And Have Different Functions, Tatsuhiko Noguchi, Marta Lenartowska, Aaron D. Rogat, Deborah J. Frank, Kathryn G. Miller Jan 2008

Proper Cellular Reorganization During Drosophila Spermatid Individualization Depends On Actin Structures Composed Of Two Domains, Bundles And Meshwork, That Are Differentially Regulated And Have Different Functions, Tatsuhiko Noguchi, Marta Lenartowska, Aaron D. Rogat, Deborah J. Frank, Kathryn G. Miller

Biology Faculty Research

During spermatid individualization in Drosophila, actin structures (cones) mediate cellular remodeling that separates the syncytial spermatids into individual cells. These actin cones are composed of two structural domains, a front meshwork and a rear region of parallel bundles. We show here that the two domains form separately in time, are regulated by different sets of actin-associated proteins, can be formed independently, and have different roles. Newly forming cones were composed only of bundles, whereas the meshwork formed later, coincident with the onset of cone movement. Polarized distributions of myosin VI, Arp2/3 complex, and the actin-bundling proteins, singed (fascin) and quail …


The Emergence Of Sex, Ursula Goodenough Dec 2007

The Emergence Of Sex, Ursula Goodenough

Biology Faculty Research

Biological traits, the foci of natural selection, are by definition emergent from the genes, proteins, and other “nothing-buts” that constitute them. Moreover, and with the exception of recently emergent “spandrels,” each can be accorded a teleological dimension—each is “for” some purpose conducive to an organism's continuation. Sex, which is “for” the generation of recombinant genomes, may be one of the most ancient and ubiquitous traits in biology. In the course of its evolution, many additional traits, such as gender and nurture, have emerged. Patterns of sexual exchange are the basis for patterns of biological evolution and are central to the …


Nodal Signaling Is Required For Closure Of The Anterior Neural Tube In Zebrafish, Allisan Aquilina-Beck, Kristine Ilagan, Qin Liu, Jennifer O. Liang Nov 2007

Nodal Signaling Is Required For Closure Of The Anterior Neural Tube In Zebrafish, Allisan Aquilina-Beck, Kristine Ilagan, Qin Liu, Jennifer O. Liang

Biology Faculty Research

Background: Nodals are secreted signaling proteins with many roles in vertebrate development. Here, we identify a new role for Nodal signaling in regulating closure of the rostral neural tube of zebrafish.


The Organizational Effects Of Oxytocin On The Central Expression Of Estrogen Receptor Alpha And Oxytocin In Adulthood, Kristin M. Kramer, Shigeto Yoshida, Eros Papademetriou, Bruce S. Cushing Sep 2007

The Organizational Effects Of Oxytocin On The Central Expression Of Estrogen Receptor Alpha And Oxytocin In Adulthood, Kristin M. Kramer, Shigeto Yoshida, Eros Papademetriou, Bruce S. Cushing

Biology Faculty Research

Background: Previous studies have demonstrated that neonatal manipulation of oxytocin (OT) has effects on the expression of estrogen receptor alpha (ER alpha) and the central production of oxytocin observed in juveniles ( at weaning, 21 days of age). The goal of this study was to determine whether the effects of neonatal manipulation of OT last into adulthood, and if the effects differ from those observed during the early postnatal period. On the first day of life, prairie voles ( Microtus ochrogaster) received one of three doses of OT (High, 3 mu g; Med, 0.3 mu g; Low, 0.03 mu g), …


Drosophila Piwi Associates With Chromatin And Interacts Directly With Hp1a, Brent Brower-Toland, Seth Findley, Ling Jiang, Li Liu, Hang Yin, Monica Dus, Pei Zhou, Sarah C.R. Elgin, Haifan Lin Sep 2007

Drosophila Piwi Associates With Chromatin And Interacts Directly With Hp1a, Brent Brower-Toland, Seth Findley, Ling Jiang, Li Liu, Hang Yin, Monica Dus, Pei Zhou, Sarah C.R. Elgin, Haifan Lin

Biology Faculty Research

The interface between cellular systems involving small noncoding RNAs and epigenetic change remains largely unexplored in metazoans. RNA-induced silencing systems have the potential to target particular regions of the genome for epigenetic change by locating specific sequences and recruiting chromatin modifiers. Noting that several genes encoding RNA silencing components have been implicated in epigenetic regulation in Drosophila, we sought a direct link between the RNA silencing system and heterochromatin components. Here we show that PIWI, an ARGONAUTE/PIWI protein family member that binds to Piwi-interacting RNAs (piRNAs), strongly and specifically interacts with heterochromatin protein 1a (HP1a), a central player in heterochromatic …