Studies on Pathogenicity Effect of Aeromonas hydrophila Infection in Juvenile Red Hybrid Tilapia Oreochromis sp.

This study was conducted to evaluate the ability of motile Aeromonas species (MAS) to induce clinical symptoms and some pathological changes in juvenile red hybrid tilapia. A standard dose of infection was selected based on predetermined LD50. Infected fish were observed for any clinical sign and symptom for 96 hours. Samples of liver, spleen and kidney were collected for histopatological changes due to Aeromonas hydrophila infection. Clinical signs of fish included abnormal swimming behaviour and loss of balance. Most of infected fish suffered from haemorrhagic eyes and lesions on the body surface. Some of the them also developed bilateral exophthalmia. Histopathological changes were observed in kidney, liver and spleen. The infected liver showed severe congestion of hepatic veins and vacuoles formation while anterior kidney manifested degeneration of excretory tubules and glomeruli followed by severe haemorrhages and hyaline droplets degeneration. Spleen on the other hand showed tissues degeneration and vacuoles formation. All targated tissues also showed deposition of haemosiderin pigments followed by proliferation of melanomacrphage centres. Development of such symptoms was associated with the infection with Aeromonas hydrophila. The current study has shown that MAS could serve as the primary cause of severe infection not only in red hybrid tilapia but may also infected other freshwater fish species.The results of histological analysis of various tissues indicates a direct correlation between disease infection and histopathological disorders observed in the tissues

The Re-Emerging Role of the State in Contemporary Russia

I examine ownership structure of Russian firms during the 1998-2006 period, where a greater emphasis is placed on motivations behind increased government ownership in the latter years, when oligarchs' opportunistic influence on the firm diminished as state ownership correspondingly increased. As this phenomenon is also correlated with improved corporate growth during the period, I argue that state participation in corporate governance acted as an effective substitute mechanism to constrain wealth-tunnelling behaviour of corporate insiders and local bureaucrats in a country defined by a weak property rights system. © 2012 Springer-Verlag

A high resolution genome-wide scan for significant selective sweeps: an application to pooled sequence data in laying chickens

In most studies aimed at localizing footprints of past selection, outliers at tails of the empirical distribution of a given test statistic are assumed to reflect locus-specific selective forces. Significance cutoffs are subjectively determined, rather than being related to a clear set of hypotheses. Here, we define an empirical p-value for the summary statistic by means of a permutation method that uses the observed SNP structure in the real data. To illustrate the methodology, we applied our approach to a panel of 2.9 million autosomal SNPs identified from re-sequencing a pool of 15 individuals from a brown egg layer line. We scanned the genome for local reductions in heterozygosity, suggestive of selective sweeps. We also employed a modified sliding window approach that accounts for gaps in the sequence and increases scanning resolution by moving the overlapping windows by steps of one SNP only, and suggest to call this a "creeping window" strategy. The approach confirmed selective sweeps in the region of previously described candidate genes, i.e. TSHR, PRL, PRLHR, INSR, LEPR, IGF1, and NRAMP1 when used as positive controls. The genome scan revealed 82 distinct regions with strong evidence of selection (genome-wide p-value<0.001), including genes known to be associated with eggshell structure and immune system such as CALB1 and GAL cluster, respectively. A substantial proportion of signals was found in poor gene content regions including the most extreme signal on chromosome 1. The observation of multiple signals in a highly selected layer line of chicken is consistent with the hypothesis that egg production is a complex trait controlled by many genes

The need for national medical licensing examination in Saudi Arabia

<p>Abstract</p> <p>Background</p> <p>Medical education in Saudi Arabia is facing multiple challenges, including the rapid increase in the number of medical schools over a short period of time, the influx of foreign medical graduates to work in Saudi Arabia, the award of scholarships to hundreds of students to study medicine in various countries, and the absence of published national guidelines for minimal acceptable competencies of a medical graduate.</p> <p>Discussion</p> <p>We are arguing for the need for a Saudi national medical licensing examination that consists of two parts: Part I (Written) which tests the basic science and clinical knowledge and Part II (Objective Structured Clinical Examination) which tests the clinical skills and attitudes. We propose this examination to be mandated as a licensure requirement for practicing medicine in Saudi Arabia.</p> <p>Conclusion</p> <p>The driving and hindering forces as well as the strengths and weaknesses of implementing the licensing examination are discussed in details in this debate.</p

Contribution of Microbe-Mediated Processes in Nitrogen Cycle to Attain Environmental Equilibrium

Nitrogen (N), the most important element, is required by all living organisms for the synthesis of complex organic molecules like amino acids, proteins, lipids etc. Nitrogen cycle is considered to be the most complex yet arguably important cycle next to carbon cycle. Nitrogen cycle includes oxic and anoxic reactions like organic N mineralization, ammonia assimilation, nitrification denitrification, anaerobic ammonium oxidation (anammox), dissimilatory nitrate reduction to ammonium (DNRA), comammox, codenitrification etc. Nitrogen cycling is one of the most crucial processes required for the recycling of essential chemical requirements on the planet. Soil microorganisms not only improve N-cycle balance but also pave the way for sustainable agricultural practices, leading to improved soil properties and crop productivity as most plants are opportunistic in the uptake of soluble or available forms of N from soil. Microbial N transformations are influenced by plants to improve their nutrition and vice versa. Diverse microorganisms, versatile metabolic activities, and varied biotic and abiotic conditions may result in the shift in the equilibrium state of different N-cycling processes. This chapter is an overview of the mechanisms and genes involved in the diverse microorganisms associated in the operation of nitrogen cycle and the roles of such microorganisms in different agroecosystems