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2004

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Articles 1 - 30 of 64

Full-Text Articles in Life Sciences

Dna Microarray Analysis Of Nitrogen Fixation And Fe(Iii) Reduction In Geobacter Sulfurreducens, Jennifer Webster, Barbara A. Methé, Kelly P. Nevin, Jessica E. Butler, Derek Lovley Dec 2004

Dna Microarray Analysis Of Nitrogen Fixation And Fe(Iii) Reduction In Geobacter Sulfurreducens, Jennifer Webster, Barbara A. Methé, Kelly P. Nevin, Jessica E. Butler, Derek Lovley

Derek Lovley

A DNA microarray representing the genome of Geobacter sulfurreducens was constructed for use in global gene expression profiling of cells under steady-state conditions with acetate as the electron donor and Fe(III) or fumarate as the electron acceptor. Reproducible differences in transcript levels were also observed in comparisons between cells grown with ammonia and those fixing atmospheric nitrogen. There was a high correlation between changes in transcript levels determined with microarray analyses and an evaluation of a subset of the genome with quantitative PCR. As expected, cells required to fix nitrogen had higher levels of transcripts of genes associated with ...


Lateral Hypothalamic Signaling Mechanisms Underlying Feeding Stimulation: Differential Contributions Of Src Family Tyrosine Kinases To Feeding Triggered Either By Nmda Injection Or By Food Deprivation, Arshad Khan, Herman H. Cheung, Elizabeth R. Gillard, Jennifer A. Palarca, Derek S. Welsbie, James W. Gurd, B. Glenn Stanley Nov 2004

Lateral Hypothalamic Signaling Mechanisms Underlying Feeding Stimulation: Differential Contributions Of Src Family Tyrosine Kinases To Feeding Triggered Either By Nmda Injection Or By Food Deprivation, Arshad Khan, Herman H. Cheung, Elizabeth R. Gillard, Jennifer A. Palarca, Derek S. Welsbie, James W. Gurd, B. Glenn Stanley

Arshad M. Khan, Ph.D.

No abstract provided.


Evidence For And Characterization Of Ca2+ Binding To The Catalytic Region Of Arabidopsis Thaliana Phospholipase Dβ, Xuemin Wang Nov 2004

Evidence For And Characterization Of Ca2+ Binding To The Catalytic Region Of Arabidopsis Thaliana Phospholipase Dβ, Xuemin Wang

Xuemin (Sam) Wang

Most types of plant phospholipase D (PLD) require Ca2+ for activity, but how Ca2+ affects PLD activity is not well understood. We reported previously that Ca2+ binds to the regulatory C2 domain that occurs in the N terminus of the Ca2+-requiring PLDs. Using Arabidopsis thaliana PLDβ and C2-deleted PLDβ (PLDβcat), we now show that Ca2+ also interacts with the catalytic regions of PLD. PLDβcat exhibited Ca2+-dependent activity, was much less active, and required a higher level of Ca2+ than the full-length PLDβ. Ca2+ binding of the proteins was stimulated by phospholipids; phosphatidylserine was the most effective among those ...


Is There An Antipredator Blood-Squirting Defense In The Bull Horned Lizard, Phrynosoma Taurus?, George Middendorf Oct 2004

Is There An Antipredator Blood-Squirting Defense In The Bull Horned Lizard, Phrynosoma Taurus?, George Middendorf

George Middendorf

No abstract provided.


The Multidisciplinary Influence Of Common Sustainability Indices, Audrey L. Mayer, Hale W. Thurston, Christopher W. Pawlowski Sep 2004

The Multidisciplinary Influence Of Common Sustainability Indices, Audrey L. Mayer, Hale W. Thurston, Christopher W. Pawlowski

Audrey Mayer

Sustainability is often poorly defined and difficult to measure. We describe several concepts from ecology, economics, and physics, that have contributed to sustainability indices, and discuss their positive and negative aspects. Indices range from mostly ecological (such as ecosystem resilience and global human carrying capacity), to those inspired by both economics and ecology (green income and maximum sustainable yield), to a mix of ecology and physics (exergy and emergy). Economic concepts such as substitutability of natural and human capital (the “weak” versus “strong” sustainability debate), and through put of natural resources through an economic system, are the basis for several ...


The Role Of Optimal Healing Environments In The Management Of Childhood Obesity, Marjorie R. Freedman, Judith S. Stern Sep 2004

The Role Of Optimal Healing Environments In The Management Of Childhood Obesity, Marjorie R. Freedman, Judith S. Stern

Marjorie R. Freedman

The prevalence of childhood and adolescent obesity has increased steadily over the past three decades such that obesity is now a major worldwide pediatric health risk factor. Pediatric obesity is associated with significant health problems, and is an important early risk factor for adult morbidity and mortality. This paper focuses on the role and components of optimal healing environments (OHEs) that may be useful in the management of childhood obesity: healing intention, healing relationships, health promotion and disease prevention, and healing spaces. Diet, physical activity, and behavior modification strategies used in the treatment of childhood obesity are also reviewed.


Soil Respiration And Nutrient Cycling In Wooded Communities Developing In Grassland, Rebecca L. Mcculley, S. R. Archer, T. W. Boutton, F. M. Hons, D. A. Zuberer Sep 2004

Soil Respiration And Nutrient Cycling In Wooded Communities Developing In Grassland, Rebecca L. Mcculley, S. R. Archer, T. W. Boutton, F. M. Hons, D. A. Zuberer

Rebecca L. McCulley

Grasslands and savannas worldwide are experiencing increases in woody plant abundance. In the subtropical Rio Grande Plains of southern Texas and northern Mexico, this change in physiognomy typically results in soil C and N accumulation. The extent to which this accumulation is the result of increased C and N inputs vs. decreased losses is not known. To address this issue, we compared soil C and N pools, soil respiration, soil microbial biomass, and potential C and N mineralization and nitrification rates in remnant grassland communities and adjacent woody plant communities known to have developed on grassland within the past 100 ...


Germination Of Silene Regia Seeds From Four Sites In Lawrence County, Illinois, Following Scarification Or Stratification, Nicolette L. Flocca, Janice M. Coons, Henry R. Owen, Brian J. Fischer, Bob E. Edgin Sep 2004

Germination Of Silene Regia Seeds From Four Sites In Lawrence County, Illinois, Following Scarification Or Stratification, Nicolette L. Flocca, Janice M. Coons, Henry R. Owen, Brian J. Fischer, Bob E. Edgin

Henry R. Owen

Silene regia Sims is an endangered prairie forb in Illinois where small isolated colonies are scattered. In La·wrence County, two sites (Allison Prairie and Chauncey Marsh) have fewer plants (6-23) than two other sites (Cmmty Road and Cemetery) with 26-45 plants. Information on seed germination in these isolated colonies is needed. Our goal was to evaluate seed germination of S. regia from colonies in Lawrence County, illinois. S. regia fruits were collected from these four sites on August 9 and 19, 1999. Seeds were scarified by cutting the seed coat, or they were stratified at 2 C for 12 ...


A Spiroplasma Associated With Tremor Disease In The Chinese Mitten Crab (Eriocheir Sinensis), Wen Wang, Bohai Wen, Gail E. Gasparich, Ningning Zhu, Liwen Rong, Jianxiu Chen, Zaikuan Xu Aug 2004

A Spiroplasma Associated With Tremor Disease In The Chinese Mitten Crab (Eriocheir Sinensis), Wen Wang, Bohai Wen, Gail E. Gasparich, Ningning Zhu, Liwen Rong, Jianxiu Chen, Zaikuan Xu

Gail Gasparich

An epidemic of tremor disease has been a serious problem in Chinese mitten crabs, Eriocheir sinensis, in China in recent years. The disease-causing agent was previously considered to be a rickettsia-like organism. Here, analysis of the 16S rRNA gene sequence, light and electron microscopy and cultivation in vitro were used to identify the agent. Sequence analysis of the 16S rRNA gene found it to have 98 % identity with that of Spiroplasma mirum. The agent was able to be passed through membrane filters with pores 220 nm in diameter and could be cultivated by inoculating the yolk sac of embryonated chicken ...


Size And Organic Content Of Eggs Of Marine Annelids, And The Underestimation Of Egg Energy Content By Dichromate Oxidation, William Jaeckle, Bruno Pernet Jul 2004

Size And Organic Content Of Eggs Of Marine Annelids, And The Underestimation Of Egg Energy Content By Dichromate Oxidation, William Jaeckle, Bruno Pernet

William Jaeckle

Dichromate oxidation is a simple technique that is often used to estimate the energy content of eggs in studies of marine invertebrate life histories (1). We used this method to measure the energy contents of the eggs of 12 species of marine annelids. In combination with measures of egg ash-free dry weight (AFDW), these data yielded estimates of AFDW-specific energy density that were mostly lower than the average weight-specific energy density of carbohydrates. This seemed unlikely to be correct, as invertebrate eggs typically contain little carbohydrate and instead are composed primarily of energy-dense protein and lipid (1, 2). After validating ...


Application Of Response Surface Methodology For Studying The Product Characteristics Of Extruded Rice-Cowpea-Groundnut Blends, Emmanuel Asare, Samuel Sefa-Dedeh, Emmanuel Ohene Afoakwa Jul 2004

Application Of Response Surface Methodology For Studying The Product Characteristics Of Extruded Rice-Cowpea-Groundnut Blends, Emmanuel Asare, Samuel Sefa-Dedeh, Emmanuel Ohene Afoakwa

Professor Emmanuel Ohene Afoakwa

Response surface methodology (with central composite rotatable design for k=3 was used to investigate the product properties of extruded rice-cowpea-groundnut blends in a single screw extruder. The combined effect of cowpea (0-20%), groundnut (0-10%), and feed moisture (14-48%) levels were used for formulation of the products. The product moisture, expansion ratio, bulk density and total colour change were studied using standard analytical methods. Well-expanded rice-legume blend extrudates of less bulk density and lower moisture content were produced at low feed moisture. Increasing legume addition affected the various shades of colour in the product. Models developed for the indices gave ...


The Microflora Of Fermented Nixtamalized Corn, Samuel Sefa-Dedeh, Beatrice Cornelius, Wisdom Amoa-Awua, Esther Sakyi-Dawson, Emmanuel Ohene Afoakwa Jul 2004

The Microflora Of Fermented Nixtamalized Corn, Samuel Sefa-Dedeh, Beatrice Cornelius, Wisdom Amoa-Awua, Esther Sakyi-Dawson, Emmanuel Ohene Afoakwa

Professor Emmanuel Ohene Afoakwa

Nixtamalization is a traditional process that improves the nutritional quality of corn. To provide a means of utilizing the nutritional benefits of nixtamalized corn and improve product acceptability, lactic acid fermentation was applied. The objective of the study was to study the microbial profile and establish the important lactobacilli of fermenting nixtamalized corn dough. Two batches of cleaned whole corn were subjected to the process of nixtamalization, using two concentrations of lime (0.5 or 1.0%), milled, made into a dough (50% moisture) and fermented spontaneously for 72 h. A control sample was prepared without alkaline treatment. pH and ...


Multidimensional Gas Chromatography-Olfactometry For Identification And Prioritization Of Malodors From Confined Animal Feeding Operations, Donald W. Wright, David K. Eaton, Lawrence T. Nielsen, Fred W. Kuhrt, Jacek A. Koziel, Jarett P. Spinhirne, David B. Parker Jul 2004

Multidimensional Gas Chromatography-Olfactometry For Identification And Prioritization Of Malodors From Confined Animal Feeding Operations, Donald W. Wright, David K. Eaton, Lawrence T. Nielsen, Fred W. Kuhrt, Jacek A. Koziel, Jarett P. Spinhirne, David B. Parker

Jacek A. Koziel

Odor profiling efforts were directed at applying to high-density livestock operations, some of the lessons learned in resolving past, highly diverse, odor-focused investigations in the consumer product industry. Multidimensional-GC-Olfactometry was utilized in an attempt to define and prioritize the basic building blocks of odor character associated with representative cattle feedyard and swine feeding operations. Although scores of potential odorant volatiles have been previously identified in high-density livestock operations, the odor profile results developed herein suggest that only a very few of these may constitute the preponderance of the odor complaints associated with these environments. This appeared to be especially true ...


Lestig1, An Extracellular Binding Partner For The Pollen Receptor Kinases Leprk1 And Leprk2, Promotes Pollen Tube Growth In Vitro, Weihua Tang, Dior R. Kelley, Ines Ezcurra, Robyn Cotter, Sheila Mccormick Jul 2004

Lestig1, An Extracellular Binding Partner For The Pollen Receptor Kinases Leprk1 And Leprk2, Promotes Pollen Tube Growth In Vitro, Weihua Tang, Dior R. Kelley, Ines Ezcurra, Robyn Cotter, Sheila Mccormick

Dior Kelley

As pollen tubes grow through the pistil they are thought to perceive and respond to diverse signals. The tomato pollen-specific receptor kinases LePRK1 and LePRK2 might participate in signaling during pollen tube growth. We previously showed that the extracellular domain of LePRK2 interacts with a pollen protein, LAT52, before but not after pollen germination. To determine whether LePRK2 might have different binding partner(s) after pollen germination, we characterized two more proteins that, like LAT52, were identified in yeast two-hybrid screens using the extracellular domains of LePRK1 and LePRK2 as baits. We show that LeSHY, a leucine-rich repeat protein from ...


Design Considerations For The Construction And Operation Of Feed Milling Facilities. Part I: Planning, Structural, And Life Safety Considerations, Gregory D. Williams, Kurt A. Rosentrater Jul 2004

Design Considerations For The Construction And Operation Of Feed Milling Facilities. Part I: Planning, Structural, And Life Safety Considerations, Gregory D. Williams, Kurt A. Rosentrater

Kurt A. Rosentrater

Feed mills represent an important segment of our food production system, supplying the nutritional need for animals in our meat supply system. Agri-industrial facilities such as feed mills have a number of unique design requirements that are relatively unknown. The purpose of this paper is to summarize state of the art design procedures for feed milling facilities constructed in North America. To this end, in Part I of this series, planning, life safety, and structural design criteria for these facilities are examined and relevant theory is presented. Additional resources are cited for further study of concepts. This paper should be ...


Osedax: Bone-Eating Marine Worms With Dwarf Males, G W. Rouse, Shana K. Goffredi, R C. Vrijenhoek Jul 2004

Osedax: Bone-Eating Marine Worms With Dwarf Males, G W. Rouse, Shana K. Goffredi, R C. Vrijenhoek

Shana Goffredi

We describe a new genus, Osedax, and two new species of annelids with females that consume the bones of dead whales via ramifying roots. Molecular and morphological evidence revealed that Osedax belongs to the Siboglinidae, which includes pogonophoran and vestimentiferan worms from deep-sea vents, seeps, and anoxic basins. Osedax has skewed sex ratios with numerous dwarf (paedomorphic) males that live in the tubes of females. DNA sequences reveal that the two Osedax species diverged about 42 million years ago and currently maintain large populations ranging from 105 to 106 adult females.


Caveolin-2 Associates With Intracellular Chlamydial Inclusions Independently Of Caveolin-1, Wilmore C. Webley, Leonard C. Norkin, Elizabeth S. Stuart Jul 2004

Caveolin-2 Associates With Intracellular Chlamydial Inclusions Independently Of Caveolin-1, Wilmore C. Webley, Leonard C. Norkin, Elizabeth S. Stuart

Wilmore C Webley

Background Lipid raft domains form in plasma membranes of eukaryotic cells by the tight packing of glycosphingolipids and cholesterol. Caveolae are invaginated structures that form in lipid raft domains when the protein caveolin-1 is expressed. The Chlamydiaceae are obligate intracellular bacterial pathogens that replicate entirely within inclusions that develop from the phagocytic vacuoles in which they enter. We recently found that host cell caveolin-1 is associated with the intracellular vacuoles and inclusions of some chlamydial strains and species, and that entry of those strains depends on intact lipid raft domains. Caveolin-2 is another member of the caveolin family of proteins ...


Vibrio Parahaemolyticus And V. Harveyi Cause Detachment Of The Epithelium From The Midgut Trunk Of The Penaeid Shrimp, Sicyonia Ingentis., Gary G. Martin, Nicole Rubin, Erica Swanson Jul 2004

Vibrio Parahaemolyticus And V. Harveyi Cause Detachment Of The Epithelium From The Midgut Trunk Of The Penaeid Shrimp, Sicyonia Ingentis., Gary G. Martin, Nicole Rubin, Erica Swanson

Gary Martin

Shrimp Sicyonia ingentis were either injected with Vibrio parahaemolyticus (104 CFU) or V. harveyi (106 CFU) or immersed in ASW containing either species at 105 CFU ml-1. These densities were shown in preliminary experiments to kill approximately half the population by 7 d. On Day 7, surviving shrimp were classified as either diseased or apparently healthy, and their midgut trunks (MGT) were examined by light and electron microscopy. All shrimp immersed in ASW containing either species of Vibrio showed detachment of the epithelium in the MGT. In shrimp injected with either species of Vibrio, epithelial detachment was common in diseased ...


The Neurobiology Of Antiepileptic Drugs, Michael Rogawski, Wolfgang Löscher Jun 2004

The Neurobiology Of Antiepileptic Drugs, Michael Rogawski, Wolfgang Löscher

Michael A. Rogawski

Antiepileptic drugs (AEDs) provide satisfactory control of seizures for most patients with epilepsy. The drugs have the remarkable ability to protect against seizures while permitting normal functioning of the nervous system. AEDs act on diverse molecular targets to selectively modify the excitability of neurons so that seizure-related firing is blocked without disturbing non-epileptic activity. This occurs largely through effects on voltage-gated sodium and calcium channels, or by promoting inhibition mediated by GABA-A (γ-aminobutyric acid, type A) receptors. The subtle biophysical modifications inchannel behaviour that are induced by AEDs are often functionally opposite to defects in channel properties that are caused ...


Responses Of Kit Foxes (Vulpes Macrotis) To Antipredator Blood-Squirting And Blood Of Texas Horned Lizards (Phrynosoma Cornutum), Wade Sherbrooke, George Middendorf, M E. Douglas Jun 2004

Responses Of Kit Foxes (Vulpes Macrotis) To Antipredator Blood-Squirting And Blood Of Texas Horned Lizards (Phrynosoma Cornutum), Wade Sherbrooke, George Middendorf, M E. Douglas

George Middendorf

Six related studies were conducted with four captive juvenile Kit Foxes (Vulpes macrotis) to test the hypothesis that blood-squirting from eye-socket tissues by Texas Horned Lizards (Phrynosoma cornutum) is a canid antipredator defense. In 16 trials, naive “hungry” foxes killed and ate adult Yarrow's Spiny Lizards (Sceloporus jarrovii; eight of eight trials) slightly more frequently than adult P. cornutum (six of eight trials). Adverse responses by foxes (head shaking) were seen in five of six trials in which Phrynosoma squirted blood. Later these experienced foxes, fed ad libitum, killed and ate mice (eight of eight trials) while largely ignoring ...


Effects Of Cowpea Fortification, Dehydration Method And Storage Time On Some Quality Characteristics Of Maize-Based Traditional Weaning Foods., Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh, Esther Sakyi-Dawson Jun 2004

Effects Of Cowpea Fortification, Dehydration Method And Storage Time On Some Quality Characteristics Of Maize-Based Traditional Weaning Foods., Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh, Esther Sakyi-Dawson

Professor Emmanuel Ohene Afoakwa

Fortification of cereal-based traditional foods with legume protein can improve their nutritional value. It is, however, important to find out the extent to which the addition of cowpea affects the desirable quality characteristics of traditional weaning foods prepared from fermented maize and also to assess the effect of dehydration method and storage time on the chemical, physico-chemical and functional properties of the products. A 3 x 2 x 4 factorial experiment with cowpea level, drying method and storage time as the respective variables was done. The traditional weaning food was prepared by steeping maize in water for 24 hours, mixed ...


Potential Role Of A Novel Psychrotolerant Member Of The Family Geobacteraceae, Geopsychrobacter Electrodiphilus Gen.Nov.,Sp.Nov.,In Electricity Production By A Marine Sediment Fuel Cell, Dawn E. Holmes, Julie S. Nicoll, Daniel R. Bond, Derek Lovley Jun 2004

Potential Role Of A Novel Psychrotolerant Member Of The Family Geobacteraceae, Geopsychrobacter Electrodiphilus Gen.Nov.,Sp.Nov.,In Electricity Production By A Marine Sediment Fuel Cell, Dawn E. Holmes, Julie S. Nicoll, Daniel R. Bond, Derek Lovley

Derek Lovley

Previous studies have shown that members of the family Geobacteraceae that attach to the anodes of sediment fuel cells are directly involved in harvesting electricity by oxidizing organic compounds to carbon dioxide and transferring the electrons to the anode. In order to learn more about this process, microorganisms from the anode surface of a marine sediment fuel cell were enriched and isolated with Fe(III) oxide. Two unique marine isolates were recovered, strains A1T and A2. They are gram-negative, nonmotile rods, with abundant c-type cytochromes. Phylogenetic analysis of the 16S rRNA, recA, gyrB, fusA, rpoB, and nifD genes indicated that ...


Speciation In The Central American Seaway: The Importance Of Taxon Sampling In The Identification Of Trans-Isthmian Geminate Pairs, Matthew T. Craig, Philip A. Hastings, Daniel J. Pondella Ii May 2004

Speciation In The Central American Seaway: The Importance Of Taxon Sampling In The Identification Of Trans-Isthmian Geminate Pairs, Matthew T. Craig, Philip A. Hastings, Daniel J. Pondella Ii

Daniel Pondella

Aim  To create a molecular phylogenetic hypothesis for the closely related serranid genera Alphestes Bloch and Schneider and Dermatolepis Gill and assess the role of the Panamanian Isthmus in speciation within these reef fishes. Location  Tropical eastern Pacific, Caribbean, and Indian Oceans. Methods  Sequence data from one nuclear (TMO-4C4) and three mitochondrial genes (16S, 12S, and cytochrome b) were used in maximum parsimony and maximum likelihood analyses. Results  Here we show that previously hypothesized trans-isthmian geminate species are not each other's closest living relatives. Species of Alphestes Bloch and Schneider in the eastern Pacific are sister taxa indicating post-closure ...


Food Based Approaches For A Healthy Nutrition In Africa, Mamoudou Hama Dicko May 2004

Food Based Approaches For A Healthy Nutrition In Africa, Mamoudou Hama Dicko

Pr. Mamoudou H. DICKO, PhD

The latest estimates of the FAO demonstrate the problems of the fight against hunger. These problems are manifested by the ever-increasing number of chronically undernourished people worldwide. Their numbers during the 1999-2001 period were estimated at about 840 million of which 798 million live in developing countries. Sub-Saharan Africa alone represented 198 million of those. In this part of Africa the prevalence of undernourishment ranges from 5-34%, causing growth retardation and insufficient weight gain among one third of the children under five years of age and resulting in a mortality of 5-15% among these children. Malnutrition resulting from undernourishment is ...


The Rpos Sigma Factor In The Dissimilatory Fe(Iii)-Reducing Bacterium Geobacter Sulfurreducens, Lorrie Adams, Susan Childers, Cinthia Núñez, Derek Lovley May 2004

The Rpos Sigma Factor In The Dissimilatory Fe(Iii)-Reducing Bacterium Geobacter Sulfurreducens, Lorrie Adams, Susan Childers, Cinthia Núñez, Derek Lovley

Derek Lovley

Geobacter sulfurreducens RpoS sigma factor was shown to contribute to survival in stationary phase and upon oxygen exposure. Furthermore, a mutation in rpoS decreased the rate of reduction of insoluble Fe(III) but not of soluble forms of iron. This study suggests that RpoS plays a role in regulating metabolism of Geobacter under suboptimal conditions in subsurface environments.


Amebiasis And Comparison Of Microscopy To Elisa Technique In Detection Of Entamoeba Histolytica And Entamoeba Dispar, Clarence Lee Apr 2004

Amebiasis And Comparison Of Microscopy To Elisa Technique In Detection Of Entamoeba Histolytica And Entamoeba Dispar, Clarence Lee

Clarence Lee

The analysis of records of amoebal infection in various hospitals in Kilimanjaro indicated frequent occurrence of amebiasis. The population over the age of five years had higher rate of amoebal infection compared to less than that of a five-year-old population; however, both age groups had similar patterns of amebiasis during January 1999 to June 2001. To investigate misdiagnosis of amebiasis, 226 patients (passive cases) in three hospitals and 616 individuals (active cases) from three different localities in Kilimanjaro were examined. In passive cases, the prevalences of Entamoeba histolytica and Entamoeba dispar were 1% and 7.3%, respectively. Among active cases ...


Novel Forms Of Structural Integration Between Microbes And A Vent Gastropod From The Indian Ocean, Shana K. Goffredi, Anders Waren, Victoria J. Orphan, Cindy L. Van Dover, Robert C. Vrijenhoek Apr 2004

Novel Forms Of Structural Integration Between Microbes And A Vent Gastropod From The Indian Ocean, Shana K. Goffredi, Anders Waren, Victoria J. Orphan, Cindy L. Van Dover, Robert C. Vrijenhoek

Shana Goffredi

Here we describe novel forms of structural integration between endo- and episymbiotic microbes and an unusual new species of snail from hydrothermal vents in the Indian Ocean. The snail houses a dense population of γ-proteobacteria within the cells of its greatly enlarged esophageal gland. This tissue setting differs from that of all other vent mollusks, which harbor sulfur-oxidizing endosymbionts in their gills. The significantly reduced digestive tract, the isotopic signatures of the snail tissues, and the presence of internal bacteria suggest a dependence on chemoautotrophy for nutrition. Most notably, this snail is unique in having a dense coat of mineralized ...


Inheritance Of Trunk Banding In The Tetra (Gymnocorymbus Ternetzi Characidae), Jack Frankel Mar 2004

Inheritance Of Trunk Banding In The Tetra (Gymnocorymbus Ternetzi Characidae), Jack Frankel

Jack Frankel

The tetra (Gymnocorymbus ternetzi) exhibits two phenotypes associated with trunk banding. Fish possess either a smoky-gray coloration with two prominent black vertical bands located directly behind the operculum (black tetra) or a lighter coloration and lack these bands (white skirt tetra). Segregation patterns observed from the progenies of 11 different crosses suggest that the inheritance of these phenotypes is controlled by two autosomal loci acting in a complementary fashion, with dominance at both loci required for the expression of the darker, banded phenotype.


Strouhal Numbers And Optimization Of Swimming By Odontocete Cetaceans, J J. Rohr, Frank E. Fish Mar 2004

Strouhal Numbers And Optimization Of Swimming By Odontocete Cetaceans, J J. Rohr, Frank E. Fish

Frank E. Fish

Swimming efficiencies of fish and cetaceans have been related to a certain synchrony between stroke cycle frequency, peak-to-peak tail/fluke amplitude and mean swimming speed. These kinematic parameters form a non-dimensional wake parameter, referred to as a Stroulial number, which for the range between 0.20 and 0.40 has been associated with enhanced swimming efficiency for fish and cetaceans. Yet to date there has been no direct experimental substantiation of what Strouhal numbers are preferred by swimming cetaceans. To address this lack of data, a total of 248 Stroubal numbers were calculated for the captive odontocete cetaceans Tursiops truncatus ...


Sulfide Ameliorates Metal Toxicity For Deep-Sea Hydrothermal Vent Archaea, Virginia P. Edgcomb, Stephen J. Molyneaux, Mak A. Saito, Karen Lloyd, Simone Böer, Carl O. Wirsen, Michael S. Atkins, Andreas Teske Mar 2004

Sulfide Ameliorates Metal Toxicity For Deep-Sea Hydrothermal Vent Archaea, Virginia P. Edgcomb, Stephen J. Molyneaux, Mak A. Saito, Karen Lloyd, Simone Böer, Carl O. Wirsen, Michael S. Atkins, Andreas Teske

Karen Lloyd

The chemical stress factors for microbial life at deep-sea hydrothermal vents include high concentrations of heavy metals and sulfide. Three hyperthermophilic vent archaea, the sulfur-reducing heterotrophs Thermococcus fumicolans and Pyrococcus strain GB-D and the chemolithoautotrophic methanogen Methanocaldococcus jannaschii, were tested for survival tolerance to heavy metals (Zn, Co, and Cu) and sulfide. The sulfide addition consistently ameliorated the high toxicity of free metal cations by the formation of dissolved metal-sulfide complexes as well as solid precipitates. Thus, chemical speciation of heavy metals with sulfide allows hydrothermal vent archaea to tolerate otherwise toxic metal concentrations in their natural environment. DOI: 10 ...