The synthesis of polygalacturonase (PG) (EC 3.2.1.15) by a strain of Aspergillus terreus was induced by polygalacturonic acid and repressed by glucose, galactose or fructose even in the presence of the inducer. The production of PG increased when the mycelium was washed free of glucose and incubated in a glucose-free medium containing the inducer, a fact that indicated the reversibility of the repression mechanism. When Actinomycin D and cycloheximide were added to the culture medium, the synthesis of PG ceased. PG synthesis increased 43% with the addition of methionine and 64% both with leucine and with tyrosine. Speci®c productivity with leucine was 210% higher than that of the control as against 149% with methionine and 70% with tyrosine. The results obtained suggest that PG synthesis is regulated by leucine.

The hepatitis E virus causes acute viral hepatitis endemic in much of the developing world and is a serious public health problem. However, due to the lack of an in vitro culture system or a small animal model, its biology and pathogenesis are poorly understood. We have shown earlier that the ORF3 protein (pORF3) of hepatitis E virus activates ERK, a member of the MAPK superfamily. Here we have explored the mechanism of pORF3-mediated ERK activation and demonstrated it to be independent of the Raf/MEK pathway. Using biochemical assays, yeast two-hybrid analysis, and intracellular fluorescence resonance energy transfer we showed that pORF3 binds Pyst1, a prototypic member of the ERKspecific MAPK phosphatase. The binding regions in the two proteins were mapped to the N terminus of pORF3 and a central portion of Pyst1. Expression of pORF3 protected ERK from the inhibitory effects of ectopically expressed Pyst1. This is the first example of a viral protein regulating ERK activation by inhibition of its cognate dual specificity phosphatase.

Viruses are known to exploit the host cell machinery for their benefit during different stages of their life cycle within the infected host. One of the major challenges for a virus during the early stages of infection is to escape recognition by the host immune system. Viruses have adopted many novel strategies to evade the host immune response or to create an immune suppressed environment. An earlier study in our laboratory has demonstrated that the ORF3 protein of the hepatitis E virus expedites the secretion of ␣ 1 microglobulin, an immunosuppressant molecule. Based on this observation, we proposed that enhanced secretion of ␣ 1 microglobulin may help maintain an immunosuppressed milieu around the infected hepatocyte (Tyagi, S., Surjit, M., Roy, A. K., Jameel, S., and Lal, S. K. (2004) J. Biol. Chem. 279, 29308 -29319). In the present study, we discovered that the ability of the ORF3 protein to expedite ␣ 1 microglobulin secretion is attributed to the PSAP motif present at the C terminus of the former. The ORF3 protein was able to associate with the tumor susceptibility gene 101 (TSG101) through the PSAP motif. Further, a PSAP motif-mutated ORF3 protein was unable to associate with TSG101 and also lost its ability to enhance the secretion of ␣ 1 microglobulin. In addition, the ORF3 protein was found to associate simultaneously with TSG101 and ␣ 1 microglobulin because all three of them were co-precipitated as a ternary complex. Finally, a dominant negative mutant of the VPS4 protein was shown to block the enhanced ␣ 1 microglobulin secretion in ORF3-expressing hepatocytes. These results suggest a mechanism by which the ORF3 protein exploits the endosomal sorting machinery to enhance the secretion of an immunosuppressant molecule (␣ 1 microglobulin) from the cultured hepatocytes.

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Abstract-Electronic commerce, frequently known as e-commerce, has explored a new world before the vendors and customers, created a bigger virtual marketplace. With the widespread use of Internet, the online business and commercial transactions have reached to an extraordinary height, almost covering more than half of the world. Another rapidly emerging technology, cloud, is one of the most popular choices for the IT industry today. Due to its versatility, storage optimization capacity, performance, 24 x 7 service availability cloud has created its great impact in the ground of E Commerce. The present era is "cloud" era of E Commerce. But cloud, due to its distributive nature, incurs some extra baggage to the E Commerce security issues. This paper focuses on various security issues in Cloud based E Commerce. The main focus will be on cloud based E Commerce services especially for B2B and B2C E Commerce.