Jawaharlal Nehru University

About: Jawaharlal Nehru University is a education organization based out in New Delhi, India. It is known for research contribution in the topics: Population & Politics. The organization has 6082 authors who have published 13455 publications receiving 245407 citations. The organization is also known as: JNU.

Drug susceptibilities of yeast cells are affected by membrane lipid composition

Abstract: In the present study we have exploited isogenic erg mutants of Saccharomyces cerevisiae to examine the contribution of an altered lipid environment on drug susceptibilities of yeast cells. It is observed that erg mutants, which possess high levels of membrane fluidity, were hypersensitive to the drugs tested, i.e., cycloheximide (CYH), o-phenanthroline, sulfomethuron methyl, 4-nitroquinoline oxide, and methotrexate. Most of the erg mutants except mutant erg4 were, however, resistant to fluconazole (FLC). By using the fluorophore rhodamine-6G and radiolabeled FLC to monitor the passive diffusion, it was observed that erg mutant cells elicited enhanced diffusion. The addition of a membrane fluidizer, benzyl alcohol (BA), to S. cerevisiae wild-type cells led to enhanced membrane fluidity. However, a 10 to 12% increase in BA-induced membrane fluidity did not alter the drug susceptibilities of the S. cerevisiae wild-type cells. The enhanced diffusion observed in erg mutants did not seem to be solely responsible for the observed hypersensitivity of erg mutants. In order to ascertain the functioning of drug extrusion pumps encoding the genes CDR1 (ATP-binding cassette family) and CaMDR1 (MFS family) of Candida albicans in a different lipid environment, they were independently expressed in an S. cerevisiae erg mutant background. While the fold change in drug resistance mediated by CaMDR1 remained the same or increased in erg mutants, susceptibility to FLC and CYH mediated by CDR1 was increased (decrease in fold resistance). Our results demonstrate that between the two drug extrusion pumps, Cdr1p appeared to be more adversely affected by the fluctuations in the membrane lipid environment (particularly to ergosterol). By using 6-[(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino-hexanoyl] sphingosyl phosphocholine (a fluorescent analogue of sphingomyelin), a close interaction between membrane ergosterol and sphingomyelin which appears to be disrupted in erg mutants is demonstrated. Taken together it appears that multidrug resistance in yeast is closely linked to the status of membrane lipids, wherein the overall drug susceptibility phenotype of a cell appears to be an interplay among drug diffusion, extrusion pumps, and the membrane lipid environment.

Information and communication technologies and health in low income countries: the potential and the constraints

Abstract: This paper outlines the potential offered by technological progress in the information and communication technologies (ICTs) industries for the health sector in developing countries, presents some examples of positive experiences in India, and considers the difficulties in achieving this potential. The development of ICTs can bring about improvements in health in developing countries in at least three ways: as an instrument for continuing education they enable health workers to be informed of and trained in advances in knowledge; they can improve the delivery of health and disaster management services to poor and remote locations; and they can increase the transparency and efficiency of governance, which should, in turn, improve the availability and delivery of publicly provided health services. These potential benefits of ICTs do not necessarily require all the final beneficiaries to be reached directly, thus the cost of a given quantum of effect is reduced. Some current experiments in India, such as the use of Personal Digital Assistants by rural health workers in Rajasthan, the disaster management project in Maharashtra and the computerized village offices in Andhra Pradesh and Pondicherry, suggest creative ways of using ICTs to improve the health conditions of local people. However, the basic difficulties encountered in using ICTs for such purposes are: an inadequate physical infrastructure; insufficient access by the majority of the population to the hardware; and a lack of the requisite skills for using them. We highlight the substantial cost involved in providing wider access, and the problem of resource allocation in poor countries where basic infrastructure for health and education is still lacking. Educating health professionals in the possible uses of ICTs, and providing them with access and "connectivity", would in turn spread the benefits to a much wider set of final beneficiaries and might help reduce the digital divide.