Multinational Tagging Efforts Illustrate Regional Scale of Distribution and Threats for East Pacific Green Turtles (Chelonia mydas agassizii)

To further describe movement patterns and distribution of East Pacific green turtles (Chelonia mydas agassizii) and to determine threat levels for this species within the Eastern Pacific. In order to do this we combined published data from existing flipper tagging and early satellite tracking studies with data from an additional 12 satellite tracked green turtles (1996-2006). Three of these were tracked from their foraging grounds in the Gulf of California along the east coast of the Baja California peninsula to their breeding grounds in Michoacán (1337-2928 km). In addition, three post-nesting females were satellite tracked from Colola beach, Michoacán to their foraging grounds in southern Mexico and Central America (941.3-3020 km). A further six turtles were tracked in the Gulf of California within their foraging grounds giving insights into the scale of ranging behaviour. Turtles undertaking long-distance migrations showed a tendency to follow the coastline. Turtles tracked within foraging grounds showed that foraging individuals typically ranged up to 691.6 km (maximum) from release site location. Additionally, we carried out threat analysis (using the cumulative global human impact in the Eastern Pacific) clustering pre-existing satellite tracking studies from Galapagos, Costa Rica, and data obtained from this study; this indicated that turtles foraging and nesting in Central American waters are subject to the highest anthropogenic impact. Considering that turtles from all three rookeries were found to migrate towards Central America, it is highly important to implement conservation plans in Central American coastal areas to ensure the survival of the remaining green turtles in the Eastern Pacific. Finally, by combining satellite tracking data from this and previous studies, and data of tag returns we created the best available distributional patterns for this particular sea turtle species, which emphasized that conservation measures in key areas may have positive consequences on a regional scale.     

ADAP2 Is an Interferon Stimulated Gene That Restricts RNA Virus Entry

Interferon stimulated genes (ISGs) target viruses at various stages of their infectious life cycles, including at the earliest stage of viral entry. Here we identify ArfGAP with dual pleckstrin homology (PH) domains 2 (ADAP2) as a gene upregulated by type I IFN treatment in a STAT1-dependent manner. ADAP2 functions as a GTPase-activating protein (GAP) for Arf6 and binds to phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P₃) and PI(3,4)P₂. We show that overexpression of ADAP2 suppresses dengue virus (DENV) and vesicular stomatitis virus (VSV) infection in an Arf6 GAP activity-dependent manner, while exerting no effect on coxsackievirus B (CVB) or Sendai virus (SeV) replication. We further show that ADAP2 expression induces macropinocytosis and that ADAP2 strongly associates with actin-enriched membrane ruffles and with Rab8a- and LAMP1-, but not EEA1- or Rab7-, positive vesicles. Utilizing two techniques—light-sensitive neutral red (NR)-containing DENV and fluorescence assays for virus internalization—we show that ADAP2 primarily restricts DENV infection at the stage of virion entry and/or intracellular trafficking and that incoming DENV and VSV particles associate with ADAP2 during their entry. Taken together, this study identifies ADAP2 as an ISG that exerts antiviral effects against RNA viruses by altering Arf6-mediated trafficking to disrupt viral entry.     

Regulation of fermentative capacity and levels of glycolytic enzymes in chemostat cultures of Saccharomyces cerevisiae

Regulation of fermentative capacity was studied in chemostat cultures of two Saccharomyces cerevisiae strains: the laboratory strain CEN.PK113-7D and the industrial bakers’ yeast strain DS28911. The two strains were cultivated at a fixed dilution rate of 0.10 h⁻¹ under various nutrient limitation regimes: aerobic and anaerobic glucose limitation, aerobic and anaerobic nitrogen limitation on glucose, and aerobic ethanol limitation. Also the effect of specific growth rate on fermentative capacity was compared in glucose-limited, aerobic cultures grown at dilution rates between 0.05 h⁻¹ and 0.40 h⁻¹. Biomass yields and metabolite formation patterns were identical for the two strains under all cultivation conditions tested. However, the way in which environmental conditions affected fermentative capacity (assayed off-line as ethanol production rate under anaerobic conditions) differed for the two strains. A different regulation of fermentative capacity in the two strains was also evident from the levels of the glycolytic enzymes, as determined by in vitro enzyme assays. With the exception of phosphofructokinase and pyruvate decarboxylase in the industrial strain, no clear-cut correlation between the activities of glycolytic enzymes and the fermentative capacity was found. These results emphasise the need for controlled cultivation conditions in studies on metabolic regulation in S. cerevisiae and demonstrate that conclusions from physiological studies cannot necessarily be extrapolated from one S. cerevisiae strain to the other.     

What can we learn from noncoding regions of similarity between genomes?

Background  

In addition to known protein-coding genes, large amounts of apparently non-coding sequence are conserved between the human and mouse genomes. It seems reasonable to assume that these conserved regions are more likely to contain functional elements than less-conserved portions of the genome.     

Amiloride does not alter NaCl avoidance in Fischer-344 rats

Fischer-344 (F-344) rats differ from other common rat strains in that they fail to show any preference for NaCl at any concentration in two- bottle preference tests. Because 100 microM amiloride partially blocks the NaCl-evoked chorda tympani (CT) response in electrophysiological studies, we tested NaCl preference (0.068-0.273 M) in F-344 rats with and without 100 microM amiloride solution as the solvent. A third group was tested with unadulterated NaCl solutions following CT transection. Amiloride had no significant effect on the NaCl preference-aversion function, whereas CT transection significantly reduced NaCl avoidance. These results suggest that the amiloride-sensitive component of the NaCl response is not necessary for F-344 rats to display avoidance of NaCl, but the entire CT input is.      

Beauveria bassiana (Balsamo) Vuillemin as an endophyte in tissue culture banana (Musa spp.)

Beauveria bassiana is considered a virulent pathogen against the banana weevil Cosmopolites sordidus. However, current field application techniques for effective control against this pest remain a limitation and an alternative method for effective field application needs to be investigated. Three screenhouse experiments were conducted to determine the ability of B. bassiana to form an endophytic relationship with tissue culture banana (Musa spp.) plants and to evaluate the plants for possible harmful effects resulting from this relationship. Three Ugandan strains of B. bassiana (G41, S204 and WA) were applied by dipping the roots and rhizome in a conidial suspension, by injecting a conidial suspension into the plant rhizome and by growing the plants in sterile soil mixed with B. bassiana-colonized rice substrate. Four weeks after inoculation, plant growth parameters were determined and plant tissue colonization assessed through re-isolation of B. bassiana. All B. bassiana strains were able to colonize banana plant roots, rhizomes and pseudostem bases. Dipping plants in a conidial suspension achieved the highest colonization with no negative effect on plant growth or survival. Beauveria bassiana strain G41 was the best colonizer (up to 68%, 79% and 41% in roots, rhizome and pseudostem base, respectively) when plants were dipped. This study demonstrated that, depending on strain and inoculation method, B. bassiana can form an endophytic relationship with tissue culture banana plants, causing no harmful effects and might provide an alternative method for biological control of C. sordidus.     

Identification of major sporulation proteins of Myxococcus xanthus using a proteomic approach

Myxococcus xanthus is a soil-dwelling, gram-negative bacterium that during nutrient deprivation is capable of undergoing morphogenesis from a vegetative rod to a spherical, stress-resistant spore inside a domed-shaped, multicellular fruiting body. To identify proteins required for building stress-resistant M. xanthus spores, we compared the proteome of liquid-grown vegetative cells with the proteome of mature fruiting body spores. Two proteins, protein S and protein S1, were differentially expressed in spores, as has been reported previously. In addition, we identified three previously uncharacterized proteins that are differentially expressed in spores and that exhibit no homology to known proteins. The genes encoding these three novel major spore proteins (mspA, mspB, and mspC) were inactivated by insertion mutagenesis, and the development of the resulting mutant strains was characterized. All three mutants were capable of aggregating, but for two of the strains the resulting fruiting bodies remained flattened mounds of cells. The most pronounced structural defect of spores produced by all three mutants was an altered cortex layer. We found that mspA and mspB mutant spores were more sensitive specifically to heat and sodium dodecyl sulfate than wild-type spores, while mspC mutant spores were more sensitive to all stress treatments examined. Hence, the products of mspA, mspB, and mspC play significant roles in morphogenesis of M. xanthus spores and in the ability of spores to survive environmental stress.     

Adaptation of acidogenic sludge to increasing glycerol concentrations for biohydrogen production

Hydrogen is a promising alternative as an energetic carrier and its production by dark fermentation from wastewater has been recently proposed, with special attention to crude glycerol as potential substrate. In this study, two different feeding strategies were evaluated for replacing the glucose substrate by glycerol substrate: a one-step strategy (glucose was replaced abruptly by glycerol) and a step-by-step strategy (progressive decrease of glucose concentration and increase of glycerol concentration from 0 to 5 g L^?1), in a continuous stirred tank reactor (12 h of hydraulic retention time (HRT), pH 5.5, 35 °C). While the one-step strategy led to biomass washout and unsuccessful H₂ production, the step-by-step strategy was efficient for biomass adaptation, reaching acceptable hydrogen yields (0.4?±?0.1 mol_H2?mol^?1 _{glycerol consumed}) around 33 % of the theoretical yield independently of the glycerol concentration. Microbial community structure was investigated by single-strand conformation polymorphism (SSCP) and denaturing gradient gel electrophoresis (DGGE) fingerprinting techniques, targeting either the total community (16S ribosomal RNA (rRNA) gene) or the functional Clostridium population involved in H₂ production (hydA gene), as well as by 454 pyrosequencing of the total community. Multivariate analysis of fingerprinting and pyrosequencing results revealed the influence of the feeding strategy on the bacterial community structure and suggested the progressive structural adaptation of the community to increasing glycerol concentrations, through the emergence and selection of specific species, highly correlated to environmental parameters. Particularly, this work highlighted an interesting shift of dominant community members (putatively responsible of hydrogen production in the continuous stirred tank reactor (CSTR)) according to the gradient of glycerol proportion in the feed, from the family Veillonellaceae to the genera Prevotella and Clostridium sp., putatively responsible of hydrogen production in the CSTR.     

Community-Level and Species-Specific Associations between Phytoplankton and Particle-Associated Vibrio Species in Delaware's Inland Bays

Vibrio species are an abundant and diverse group of bacteria that form associations with phytoplankton. Correlations between Vibrio and phytoplankton abundance have been noted, suggesting that growth is enhanced during algal blooms or that association with phytoplankton provides a refuge from predation. Here, we investigated relationships between particle-associated Vibrio spp. and phytoplankton in Delaware''s inland bays (DIB). The relative abundances of particle-associated Vibrio spp. and algal classes that form blooms in DIB (dinoflagellates, diatoms, and raphidophytes) were determined using quantitative PCR. The results demonstrated a significant correlation between particle-associated Vibrio abundance and phytoplankton, with higher correlations to diatoms and raphidophytes than to dinoflagellates. Species-specific associations were examined during a mixed bloom of Heterosigma akashiwo and Fibrocapsa japonica (Raphidophyceae) and indicated a significant positive correlation for particle-associated Vibrio abundance with H. akashiwo but a negative correlation with F. japonica. Changes in Vibrio assemblages during the bloom were evaluated using automated ribosomal intergenic spacer analysis (ARISA), which revealed significant differences between each size fraction but no significant change in Vibrio assemblages over the course of the bloom. Microzooplankton grazing experiments showed that losses of particle-associated Vibrio spp. may be offset by increased growth in the Vibrio population. Moreover, analysis of Vibrio assemblages by ARISA also indicated an increase in the relative abundance for specific members of the Vibrio community despite higher grazing pressure on the particle-associated population as a whole. The results of this investigation demonstrate links between phytoplankton and Vibrio that may lead to predictions of potential health risks and inform future management practices in this region.