Virus-host Interactions during Hepatitis C Virus Entry - Implications for Pathogenesis and Novel Treatment Approaches

Hepatitis C virus (HCV) is a member of the Flaviviridae family and causes acute and chronic hepatitis. Chronic HCV infection may result in severe liver damage including liver cirrhosis and hepatocellular carcinoma. The liver is the primary target organ of HCV, and the hepatocyte is its primary target cell. Attachment of the virus to the cell surface followed by viral entry is the first step in a cascade of interactions between the virus and the target cell that is required for successful entry into the cell and initiation of infection. This step is an important determinant of tissue tropism and pathogenesis; it thus represents a major target for antiviral host cell responses, such as antibody-mediated virus neutralization. Following the development of novel cell culture models for HCV infection our understanding of the HCV entry process and mechanisms of virus neutralization has been markedly advanced. In this review we summarize recent developments in the molecular biology of viral entry and its impact on pathogenesis of HCV infection, development of novel preventive and therapeutic antiviral strategies.     

The social, moral, ethical, legal and political implications of today's biological technologies: an Indian point of view

The last 50 years have seen an increasing emphasis on ethical, moral, social, legal, political and economic implications of science for reasons that are discussed in this article. Biotechnology has been no exception to this trend. Areas of biotechnology where the above implications have been important, are briefly described. Ethical and related issues in today's biology-based technologies are discussed with special reference to India. Examples of technological exploitation within a country, or of one country by another, using modern biology-based technologies are given. The possible implications of one new and emerging biology-based technology are discussed. It is concluded that a well-informed and knowledgeable society is the only assured insurance against possible misuse of biology-based technologies of today and tomorrow, including their use for the exploitation of people. The recent decision of the Prime Minister of India to set up a National Knowledge Commission is mentioned in this context.     

The ichthyosaur integument: skin fibers, a means for a strong, flexible and smooth skin

The ichthyosaur skin is examined in order to further our understanding of the adaptation of these animals to the aquatic medium and their locomotory efficiency. Softtissue structures in two excellently preserved specimens of the ichthyosaur Stenopterygius quadricissus and in a partial skull of Ichthyosaurus provide unique data on the integument of advanced or tunniform ichthyosaurs. A system of fibers of three classes based on thickness and in different levels of the integument covered almost the entire surface of the body. The thickest fibers are located deepest in the skin and the thinnest outermost. The latter consist of at least two superimposed layers of fine fibers that extend in opposing directions to form a lattice or orthogonal meshwork. The angles of these fibers vary between 25 ° and 75 ° to the long axis of the animals, depending on their location in the body. The fibers of the two other size classes, lying deeper in the tissue, were observed in single layers. The thickest fibers extend in near parallel rows approximately 60 °-80 ° to the long axis of the animal in the area near the midpoint of the body and 90 ° in the post-dorsal fin region. The intermediate-sized fibers were apparently oriented at ca. 50 °-75 ° to the animal's long axis and were regularly spaced. Of considerable interest is their attachment dorsally to longitudinal fibers. This contrasts with the general condition of helically arranged fibers in fast-swimming marine vertebrates such as tuna and sharks, but compares with the condition in sirenians. Fibers were observed in the dorsal and caudal fins but not in the limbs. The fibers in ichthyosaurs are the thickest so far noted in marine vertebrates. The presence of a complex system of fibers, which includes an orthogonal meshwork of the finest of these, suggests that creasing of the skin would have been minimized, a condition highly important in reducing drag during the locomotion of marine animals.     

Contribution by farmers' survival strategies to soil erosion in the Linthipe River Catchment: implications for biodiversity conservation in Lake Malawi/Nyasa

Sediment discharge into Lake Malawi is threatening its ecologicalimportance, thereby inflicting serious socio-economic consequences upon peopledependent on this ecosystem. The discharge is attributed to high rates oferosion in the Lake's catchment, principally occurring on agriculturalland. This study examines how survival strategies, such as expansion ofcultivated farmland and use of low fertilizer application rates, enhance thelikelihood of erosion in the Linthipe River Catchment – one of theLake's important river catchments. As such, it shows that the magnitude oferosion is significantly correlated to the amount of farmland cultivated byestate farmers and smallholders (r = 0.18,P = 0.03, and r = 0.19,P = 0.003 respectively). The low correlation coefficientsuphold the long-established fact that physical variables such as soilerodibility (vulnerability of soil to erosion), rainfall erosivity (thepotential of rainfall to cause erosion), and topography, also play major rolesin erosion processes. Nonetheless they do show that area of cultivated landcontributes to erosion. Additionally, the study shows that yields of importantcrops such as maize and tobacco are low because of insufficient use offertilizers. To compensate for the low yields, farmers rely on extending sizesof land that they cultivate thereby exposing more land to erosive forces ofrainfall. The study, therefore, concludes that Lake Malawi's biodiversityis under threat. In order to sustain the biodiversity, it is necessary toeliminate the need to increase farmland by means of agricultural intensificationthat incorporates appropriate soil-conservation measures.