Trematode Prevelance as an Indicator for Galveston Marsh Health

Digenean trematodes have complex life histories involving several hosts and life stages. They are sensitive to biotic and abiotic factors such as metal pollutants and extreme pH and temperature, possibly making them valuable bioindicators for natural and anthropogenic disturbances. To test this, trematode diversity in the plicate horn snail, Cerithidia pliculosa, from four different marsh systems around Galveston, including relatively pristine marshes, marshes heavily impacted by garbage and recently restored marshes, was evaluated to determine whether trematodes can be used locally as a bioindicator for marsh health. The snails from the marsh near East Lagoon a marsh with a high incidence of anthropogenic garbage, had a 92% infection rate with 7 of the 8 species found in this study while the marsh along Highway 45, an old restored marsh, only had a 7% infection rate with 2 of the 8 species found. The third marsh, located near Sportsman’s Road in West Galveston Bay had 3 species of parasites with a 33% infection rate. The fourth marsh was excluded from further analysis, as not enough host snails could be collected. The differences in trematode prevalence could be attributed to a number of factors such as recreational fishing activities, pollution, host density and physical properties of the marshes. Further studies are necessary to accurately determine whether trematode diversity in Galveston is a factor of natural or anthropogenic affects

Characterization of Sigma Factor Genes in Streptomyces lividans TK24 Using a Genomic Library-Based Approach for Multiple Gene Deletions

Alternative sigma factors control numerous aspects of bacterial life, including adaptation to physiological stresses, morphological development, persistence states and virulence. This is especially true for the physiologically complex actinobacteria. Here we report the development of a robust gene deletions system for Streptomyces lividans TK24 based on a BAC library combined with the λ-Red recombination technique. The developed system was validated by systematically deleting the most highly expressed genes encoding alternative sigma factors and several other regulatory genes within the chromosome of S. lividans TK24. To demonstrate the possibility of large scale genomic manipulations, the major part of the undecylprodigiosin gene cluster was deleted as well. The resulting mutant strains were characterized in terms of morphology, growth parameters, secondary metabolites production and response to thiol-oxidation and cell-wall stresses. Deletion of SLIV_12645 gene encoding S. coelicolor SigR1 ortholog has the most prominent phenotypic effect, resulted in overproduction of actinorhodin and coelichelin P1 and increased sensitivity to diamide. The secreted proteome analysis of SLIV_12645 mutant revealed SigR1 influence on trafficking of proteins involved in cell wall biogenesis and refactoring. The reported here gene deletion system will further facilitate work on S. lividans strain improvement as a host for either secondary metabolites or protein production and will contribute to basic research in streptomycetes physiology, morphological development, secondary metabolism. On the other hand, the systematic deletion of sigma factors encoding genes demonstrates the complexity and conservation of regulatory processes conducted by sigma factors in streptomycetes

Proteases of haematophagous arthropod vectors are involved in blood-feeding, yolk formation and immunity : a review

Ticks, triatomines, mosquitoes and sand flies comprise a large number of haematophagous arthropods considered vectors of human infectious diseases. While consuming blood to obtain the nutrients necessary to carry on life functions, these insects can transmit pathogenic microorganisms to the vertebrate host. Among the molecules related to the blood-feeding habit, proteases play an essential role. In this review, we provide a panorama of proteases from arthropod vectors involved in haematophagy, in digestion, in egg development and in immunity. As these molecules act in central biological processes, proteases from haematophagous vectors of infectious diseases may influence vector competence to transmit pathogens to their prey, and thus could be valuable targets for vectorial control

Measuring malnutrition and dietary diversity: theory and evidence from India

Adequate nutrition constitutes one of the most basic dimensions of human well-being. Ample evidence exists for the functional link between a diverse diet and health outcomes or economic performance. However, a concise measure to capture nutritional diversity that utilizes typical household-level data, often the only data available in developing countries, is yet to be developed. In this paper, I propose a theoretical framework for such a measure by extending the Alkire-Foster (AF) methodology. The new framework enables the calculation of both the incidence and intensity of nutritional deprivation. Applying this framework, I construct a Nutritional Deprivation Index (NDI) for Indian states using household survey data on food consumption. The NDI is unique, and, compared to existing measures, it is more effective in both identifying the inadequately nourished and revealing the extent of food deprivation

Measuring malnutrition and dietary diversity: theory and evidence from India

Adequate nutrition constitutes one of the most basic dimensions of human well-being. Ample evidence exists for the functional link between a diverse diet and health outcomes or economic performance. However, a concise measure to capture nutritional diversity that utilizes typical household-level data, often the only data available in developing countries, is yet to be developed. In this paper, I propose a theoretical framework for such a measure by extending the Alkire-Foster (AF) methodology. The new framework enables the calculation of both the incidence and intensity of nutritional deprivation. Applying this framework, I construct a Nutritional Deprivation Index (NDI) for Indian states using household survey data on food consumption. The NDI is unique, and, compared to existing measures, it is more effective in both identifying the inadequately nourished and revealing the extent of food deprivation