Life Sciences Commons^™

Nucleotide And Phospholipid-Dependent Control Of Ppxd And C-Domain Association For Seca Atpase, Don Oliver

Don Oliver

The SecA ATPase motor is a central component of the eubacterial protein translocation machinery. It is comprised of N- and C-domain substructures, where the N-domain is comprised of two nucleotide-binding domains that flank a preprotein-binding domain (PPXD), while the C-domain binds phospholipids as well as SecB chaperone. Our recent crystal structure of Bacillus subtilis SecA protomer [Hunt, J. F., Weinkauf, S., Henry, L., Fak, J. J., McNicholas, P., Oliver, D. B., and Deisenhofer, J. (2002) Science 297, 2018-2026] along with experimental support for the correct dimer structure [Ding, H., Hunt, J. F., Mukerji, I., and Oliver, D. (2003) Biochemistry 42, …

Muc4/Muc4 Functions And Regulation In Cancer., Goldi Kozloski

Goldi A Kozloski

Primordial Germ Cell-Like Cells Differentiated In Vitro From Skin-Derived Stem Cells, Katja Linher, Paul Dyce, Julang Li

Paul W. Dyce

Background We have previously demonstrated that stem cells isolated from fetal porcine skin have the potential to form oocyte-like cells (OLCs) in vitro. However, primordial germ cells (PGCs), which must also be specified during the stem cell differentiation to give rise to these putative oocytes at more advanced stages of culture, were not systematically characterized. The current study tested the hypothesis that a morphologically distinct population of cells derived from skin stem cells prior to OLC formation corresponds to putative PGCs, which differentiate further into more mature gametes.

Methodology/Principal Findings When induced to differentiate in an appropriate microenvironment, a subpopulation …

Hu Binding To Bent Dna: A Fluorescence Resonance Energy Transfer And Antisotropy Study, Ishita Mukerji

Ishita Mukerji

HU, an architectural DNA-binding protein, either stabilizes DNA in a bent conformation or induces a bend upon binding to give other proteins access to the DNA. In this study, HU binding affinity for a bent DNA sequence relative to a linear sequence was investigated using fluorescence anisotropy measurements. A static bend was achieved by the introduction of two phased A4T4 tracts in a 20 bp duplex. Binding affinity for 20 bp duplexes containing two phased A-tracts in either a 5'-3' or 3'-5' orientation was found to be almost 10-fold higher than HU binding to a random sequence 20 bp duplex …

My Embarrassment At Not Knowing Heinich, Winfried S. Peters

Winfried S. Peters

Decarboxylation Of L-Dopa And 5-Hydroxytryptophan In Dispersed Rat Pancreas Acinar Cells, E. Yu, L. Stern, A. Tenenhouse

Edward Yu

Amino acid decarboxylation activity in dispersed rat pancreas acinar cells and fractions derived by differential centrifugation of homogenate of these cells was studied. The rate of decarboxylation was measured by determining the rate of production of the [3H]-amine from [3H]-amino acid or the rate of production of 14CO2 from the [14C]-carboxy-labelled amino acid. Only the hydroxylated amino acids L-dopa and 5-hydroxytryptophan are decarboxylated by intact dispersed pancreas acinar cells or cell homogenates at all pH values and amino acid concentrations tested. The decarboxylase activity is located exclusively in the cell cytosol. Each substrate competitively inhibits the decarboxylation of the other …

The Role Of B93 Cys In The Inhibition Of Hb S Fiber Formation, Ishita Mukerji

Ishita Mukerji

No abstract provided.

The Effects Of Nucleotides On Muts-Dna Binding Kinetics Clarify The Role Of Muts Atpase Activity In Mismatch Repair, Manju Hingorani

Manju Hingorani

MutS protein initiates mismatch repair with recognition of a non-Watson-Crick base-pair or base insertion/deletion site in DNA, and its interactions with DNA are modulated by ATPase activity. Here, we present a kinetic analysis of these interactions, including the effects of ATP binding and hydrolysis, reported directly from the mismatch site by 2-aminopurine fluorescence. When free of nucleotides, the Thermus aquaticus MutS dimer binds a mismatch rapidly (k(ON)=3 x 10(6) M(-1) s(-1)) and forms a stable complex with a half-life of 10 s (k(OFF)=0.07 s(-1)). When one or both nucleotide-binding sites on the MutS*mismatch complex are occupied by ATP, the complex …

Contribution Of Msh2 And Msh6 Subunits To The Asymmetric Atpase And Dna Mismatch Binding Activities Of Saccharomyces Cerevisiae Msh2–Msh6 Mismatch Repair Protein, Manju Hingorani

Manju Hingorani

Previous analyses of both Thermus aquaticus MutS homodimer and Saccharomyces cerevisiae Msh2–Msh6 heterodimer have revealed that the subunits in these protein complexes bind and hydrolyze ATP asymmetrically, emulating their asymmetric DNA binding properties. In the MutS homodimer, one subunit (S1) binds ATP with high affinity and hydrolyzes it rapidly, while the other subunit (S2) binds ATP with lower affinity and hydrolyzes it at an apparently slower rate. Interaction of MutS with mismatched DNA results in suppression of ATP hydrolysis at S1—but which of these subunits, S1 or S2, makes specific contact with the mismatch (e.g., base stacking by a conserved …

Model-Based Global Analysis Of Heterogeneous Experimental Data Using Gfit, Manju Hingorani

Manju Hingorani

Regression analysis is indispensible for quantitative understanding of biological systems and for developing accurate computational models. By applying regression analysis, one can validate models and quantify components of the system, including ones that cannot be observed directly. Global (simultaneous) analysis of all experimental data available for the system produces the most informative results. To quantify components of a complex system, the dataset needs to contain experiments of different types performed under a broad range of conditions. However, heterogeneity of such datasets complicates implementation of the global analysis. Computational models continuously evolve to include new knowledge and to account for novel …

Metazoan Stress Granule Assembly Is Mediated By P-Eif2alpha-Dependent And -Independent Mechanisms, Natalie Farny, Nancy Kedersha, Pamela Silver

Natalie G. Farny

Stress granules (SGs) are cytoplasmic bodies wherein translationally silenced mRNAs are recruited for triage in response to environmental stress. We report that Drosophila cells form SGs in response to arsenite and heat shock. Drosophila SGs, like mammalian SGs, are distinct from but adjacent to processing bodies (PBs, sites of mRNA silencing and decay), require polysome disassembly, and are in dynamic equilibrium with polysomes. We further examine the role of the two Drosophila eIF2alpha kinases, PEK and GCN2, in regulating SG formation in response to heat and arsenite stress. While arsenite-induced SGs are dependent upon eIF2alpha phosphorylation, primarily via PEK, heat-induced …

Maximum Likelihood Estimates Of Species Trees: How Accuracy Of Phylogenetic Inference Depends Upon The Divergence History And Sampling Design, John Mccormack, Huateng Huang, L. Knowles

John E. McCormack

The understanding that gene trees are often in discord with each other and with the species trees that contain them has led researchers to methods that incorporate the inherent stochasticity of genetic processes in the phylogenetic estimation procedure. Recently developed methods for species-tree estimation that not only consider the retention and sorting of ancestral polymorphism but also quantify the actual probabilities of incomplete lineage sorting are expected to provide an improvement over earlier summary-statistic based approaches that discard much of the information content of gene trees. However, these new methods have yet to be tested on truly challenging evolutionary histories …

Conformational Changes In Receptor Tyrosine Kinase Signaling: An Erbb Garden Of Delights., Goldi Kozloski

Goldi A Kozloski

Life History, Sexual Dimorphism And 'Ornamental' Feathers In The Mesozoic Bird Confuciusornis Sanctus., Winfried S. Peters, Dieter Stefan Peters

Winfried S. Peters

Stranger In A Strange Land: Biotechnology And The Federal Circuit, Lawrence Sung

Lawrence M. Sung

No abstract provided.

Salty Students At Risk

Leonard Piché

No abstract provided.

Identifying Conservation-Priority Areas In The Tropics: A Land-Use Change Modeling Approach, Shaily Menon, R. Gil Pontius Jr., Joseph Rose, M. Khan, Kamaljit Bawa

Shaily Menon

Most quantitative methods for identifying conservation-priority areas require more detailed knowledge about the extent and distribution of biodiversity than is currently available. Accelerated and irreversible losses of biodiversity call for the development of alternative methods to identify priority sites for biodiversity inventory and protection. We focused on the state of Arunachal Pradesh, a biodiversity-rich region in northeast India. We used a geographic information system and spatially explicit modeling to examine the correlation of land-cover and land-use patterns with biogeophysical characteristics and to project future patterns of land-use change. In 1988, 70% of Arunachal Pradesh was covered by forest. We project …

Hdl-Cholesterol-Raising Effect Of Orange Juice In Subjects With Hypercholesterolemia, Elzbieta Kurowska, J. Spence, John Jordan, Stephen Wetmore, David Freeman, Leonard Piché, Paula Serratore

Leonard Piché

Background: Orange juice-a rich source of vitamin C, folate, and flavonoids such as hesperidin-induces hypocholesterolemic responses in animals. Objective: We determined whether orange juice beneficially altered blood lipids in subjects with moderate hypercholesterolemia. Design: The sample consisted of 16 healthy men and 9 healthy women with elevated plasma total and LDL-cholesterol and normal plasma triacylglycerol concentrations. Participants incorporated 1, 2, or 3 cups (250 mL each) of orange juice sequentially into their diets, each dose over a period of 4 wk. This was followed by a 5-wk washout period. Plasma lipid, folate, homocyst(e)ine, and vitamin C (a compliance marker) concentrations …

Understanding Screen-Related Sedentary Behavior And Its Contributing Factors Among School-Aged Children: A Social-Ecologic Exploration, Meizi He, Stewart Harris, Leonard Piché, Charlene Beynon

Leonard Piché

Purpose: To explore the factors that contribute to children's screen-related sedentary (S-RS) behaviors. Settings: Elementary schools. Subjects: A random sample of children in grades five and six and their parents. Measures: The outcome measure was children's S-RS activity level measured by a self-administered questionnaire. A full spectrum of potential contributing factors for children's S-RS behaviors was obtained through surveys. Multilevel linear regression methods were used to determine the associations between these factors and children's screen time (hours per day) and results were expressed as regression coefficients (g). Results: Of 955 child-parent pairs in 14 participating schools, 508 pairs (53%) completed …

Brain, Mind And Behaviour - Emerging Biological Connections, Amresh Srivastava

Amresh Srivastava

No abstract provided.

Ligand-Dependent Effects On The Conformational Equilibrium Of The Na+,K+-Atpase As Monitored By Voltage Clamp Fluorometry, Robert Dempski, Stefan Geys, Ernst Bamberg

Robert E. Dempski

Voltage clamp fluorometry was used to monitor conformational changes associated with electrogenic partial reactions of the Na(+),K(+)-ATPase after changes in the concentration of internal sodium (Na(+)(i)) or external potassium (K(+)(o)). To probe the effects of the Na(+)(i) concentration on the Na(+) branch of the Na(+),K(+)-ATPase, oocytes were depleted of Na(+)(i) and then loaded with external sodium (Na(+)(o)) using the amiloride-sensitive epithelial sodium channel. The K(+) branch of the Na(+),K(+)-ATPase was studied by exposing the oocytes to different K(+)(o) concentrations in the presence and absence of Na(+)(o) to obtain additional information on the apparent affinity for K(+)(o). Our results demonstrate that …

Varroa In The Aloha State, Tammy Horn

Tammy Horn

The Hawaiian word for fate is hopena, and since the early 1900s, it’s been a matter of hopena that Varroa mites would eventually come to the Islands. The inevitability increased in 2001 when APHIS/USDA forced Hawai’i to allow transshipments of queens and package bees from New Zealand to Canada to pass through its ports. Since Varroa arrived on Oahu in 2006 and on the Big Island in 2008, many agencies have been working together to create appropriate infrastructure to address the latest arrival. According to Hawai’i Department of Agriculture (HDOA) branch chief Neil Reimer, 'Before Varroa showed up in Hawai’i, …

Happy Serf Liberation Day: China And Tibet, Stephen Asma

Stephen T Asma

No abstract provided.

Landscape Genetics Of California Mule Deer (Odocoileus Hemionus): The Roles Of Ecological And Historical Factors In Generating Differentiation, Katherine Pease, Adam Freedman, John Pollinger, John Mccormack, Wolfgang Buermann, Jeff Rodzen, Jim Banks, Erin Meredith, Vernon Bleich, Robert Schaefer, Ken Jones, Robert Wayne

John E. McCormack

Landscape genetics is an emerging discipline that utilizes environmental and historical data to understand geographic patterns of genetic diversity. Niche modelling has added a new dimension to such efforts by allowing species–environmental associations to be projected into the past so that hypotheses about historical vicariance can be generated and tested independently with genetic data. However, previous approaches have primarily utilized DNA sequence data to test inferences about historical isolation and may have missed very recent episodes of environmentally mediated divergence. We type 15 microsatellite loci in California mule deer and identify five genetic groupings through a Structure analysis that are …

Green Fluorescent Protein Is Superior To Blue Fluorescent Protein As A Quantitative Reporter Of Promoter Activity In E-Coli., James Lissemore, Joshua Bays, Molly Calvey, Lucas Reineke, Anne Colaviagianni, Melissa Tscheiner, David Mascotti

David P. Mascotti

Fluorescent proteins related to and derived from green fluorescent protein (GFP) are widely used as tools for investigating a wide range of biological processes. In particular, GFP and its relatives have been used extensively as qualitative reporters of gene expression in many different organisms, but relatively few studies have investigated fluorescent proteins as quantitative reporters of gene expression. GFP has some limitations as a reporter gene, including possible toxicity when expressed at high levels. Therefore, it would be useful if other fluorescent proteins could be identified for use as quantitative reporters. Toward this end, we investigated BFP as a quantitative …

Two New Species Of Cave-Dwelling Beetles Trechus Clairville Of Fulvus-Group In Portugal, Ana Reboleira, Fernando Gonçalves, Artur Serrano

Ana Sofia P.S. Reboleira

Two new cave-dwelling ground beetle species, Trechus gamae sp. n. and Trechus lunai sp. n., from Portugal, are described. The new species are included in the Trechus fulvus-group by their morphological characters. The work provides diagnostic characters in particular those of the structure of male genitalia, and the distribution of the hypogean species of the fulvus -group at the Estremenho Karstic Massif is mapped. Some comments on the seasonal activity of T. gamae sp. n. are also given. An identification key to the males of the T. fulvus-group species from the Estremenho Karstic Massif is presented, and biogeographical comments are …

Role Of Transglutaminase 2 In Liver Injury Via Cross-Linking And Silencing Of Transcription Factor Sp1., Hideki Tatsukawa, Yayoi Fukaya, Gordon Frampton, Antonio Martinez-Fuentes, Kenji Suzuki, Ting-Fang Kuo, Keisuke Nagatsuma, Kentaro Shimokado, Masataka Okuno, Jian Wu, Siiri Iismaa, Tomokazu Matsuura, Hidekazu Tsukamoto, Mark A Zern, Robert M Graham, Soichi Kojima

jian duan wu

BACKGROUND & AIMS: Despite high morbidity and mortality of alcoholic liver disease worldwide, the molecular mechanisms underlying alcohol-induced liver cell death are not fully understood. Transglutaminase 2 (TG2) is a cross-linking enzyme implicated in apoptosis. TG2 levels and activity are increased in association with various types of liver injury. However, how TG2 induces hepatic apoptosis is not known. METHODS: Human hepatic cells or primary hepatocytes from rats or TG2+/+ and TG2-/- mice were treated with ethanol. Mice were administered anti-Fas antibody or alcohol. Liver sections were prepared from patients with alcoholic steatohepatitis. Changes in TG2 levels, Sp1 cross-linking and its …

A Conserved Ccch-Type Zinc Finger Protein Regulates Mrna Nuclear Adenylation And Export, Natalie Farny, Jessica Hurt, Robert Obar, Steven Gygi, Pamela Silver, Bo Zhai

Natalie G. Farny

Coupling of messenger RNA (mRNA) nuclear export with prior processing steps aids in the fidelity and efficiency of mRNA transport to the cytoplasm. In this study, we show that the processes of export and polyadenylation are coupled via the Drosophila melanogaster CCCH-type zinc finger protein CG6694/dZC3H3 through both physical and functional interactions. We show that depletion of dZC3H3 from S2R+ cells results in transcript hyperadenylation. Using targeted coimmunoprecipitation and liquid chromatography mass spectrometry (MS)/MS techniques, we characterize interactions of known components of the mRNA nuclear export and polyadenylation machineries with dZC3H3. Furthermore, we demonstrate the functional conservation of this factor, …

Defining Behavioral And Molecular Differences Between Summer And Migratory Monarch Butterflies, Robert Gegear, Haisun Zhu, Amy Casselman, Sriramana Kanginakudru, Steven Reppert

Robert J. Gegear

Background: In the fall, Eastern North American monarch butterflies (Danaus plexippus) undergo a magnificent long-range migration. In contrast to spring and summer butterflies, fall migrants are juvenile hormone deficient, which leads to reproductive arrest and increased longevity. Migrants also use a time-compensated sun compass to help them navigate in the south/southwesterly direction en route for Mexico. Central issues in this area are defining the relationship between juvenile hormone status and oriented flight, critical features that differentiate summer monarchs from fall migrants, and identifying molecular correlates of behavioral state. Results: Here we show that increasing juvenile hormone activity to induce summer-like …

Chapter 20:The Impact Of Probiotics On Maternal And Child Health: Clinical Evidence., Kingsley Anukam, Gregor Reid

Kingsley C Anukam

Key Points • Alleviating the problems of maternal and child health in countries with large malnourished and/or HIV-infected populations, will require multidimensional approaches including holistic and pharmaceutical interventions. • Urogenital infections have a major role in preterm labor and the well-being of newborns. • Probiotics show potential in reducing the risk of recurrence of urinary tract infection (UTI). • There is some evidence to suggest that probiotics can have a role to play in bacterial vaginosis (BV) and maternal health. • The role of probiotics in a number of newborn, and childhood diseases is reviewed in this chapter.