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Archive for the ‘Medicine’ Category

RNAi is fast emerging as a wonderful tool for inhibiting gene expression in a sequence specific manner. The applications of this technology are two-fold: to study gene function, and use as a therapeutic agent in treating many diseases. As a therapeutic agent it finds applications in antiviral treatments because RNAi has been shown to successfully inhibit virus replication. In a report published on 8 November, 2007, in the Retrovirology, Naito et al., describe the design of antiviral siRNA targeted against HIV-I. To create effective antiviral siRNAs against HIV is a daunting task as the virus mutates at a very high frequency. The researchers first analyzed the HIV-I group M sequences available in the Los Alamos HIV Sequence Database and then found those regions which are highly conserved. Using these conserved regions as target sites, they designed optimal antiviral siRNAs. 21-mer siRNA sequences were generated for all the possible HIV-I sequences. The conserved sequences identified in HIV-I genome included the TATA sequence, polyadenylation signal (AAUAAA), regions essential for viral replication regulation, the primer activation signal (PAS), primer binding site (PBS), packaging signal (ψ), central polypurine tract (cPPT), central termination sequence (CTS), and 3 polypurine tract (3 PPT). A total of 216 highly conserved (>70%) siRNA targets were identified. 41 siRNAs (23 siRNAs out of 216 mentioned above and 18 more siRNAs targeted against moderately conserved regions) were subjected to target mRNA cleavage assay for functional validation using real-time RT-PCR. HeLa cells were cotransfected with vector expressing reporter mRNA that contains the siRNA target site and the corresponding siRNA. Then the potency of siRNAs was monitored by real-time RT-PCR. siRNAs were evaluated for their antiviral efficacy against HIV subtypes B, B’, C and CRF01_AE.
The study clearly demonstrated that 39 out of the 41 siRNAs gave more than >60% silencing; and 26 of the 41 siRNAs effectively inhibited viral replication of all four strains by >80%. The results of the study are quite remarkable and point towards the efficient use of siRNA for inhibiting viral gene expression and replication. The study also paved the way for using siRNAs against divergent HIV-I strains. However, the extreme genetic diversity and high mutation rate of the virus has hindered the creation of a single siRNA effective against all HIV-I strains found in the world. The use of this technology for as a highly effective treatment might be possible in the future and this study could be applied to other pathogens like SARS, influenza virus, etc.

Read the article here.


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The Ri (root-inducing) plasmid of Agrobacterium rhizogenes carries agropine genes. When A. rhizogenes infects a plant, a portion of the Ri plasmid DNA enters the host plant cell and causes the production of hairy roots at the site of action. A foreign gene could be inserted into modified Ri plasmid and the recombinant DNA (plasmid) could be introduced into plants in much the same way as with the Ti plasmid of A. tumefaciens. The recombinant Ri plasmid would induce the production of hairy roots after the infection of the host plant. Scientists are now trying to use these hairy roots as potential drug factories. In a new study, scientists have successfully maintained a transgenic hairy root culture alive for 4-and-a-half years, and they hope that this could be a great source of continuous drug production. Read the full story here.

via: ScientificBlogging


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The Saint Louis University School of Medicine researchers have announced a major finding that could lead to development of better therapies for one of the most common neurological disorders, Parkinson’s disease.

Dopamine is required for smooth and coordinated function of the body’s muscles and movements. Parkinson’s disease occurs when dopamine producing nerve cells of substantia nigra region of the brain die or become impaired. The symptoms of the disease develop after more than 80% of these dopamine-producing cells die or are damaged.

The breakthrough came when the scientists found that during Parkinson’s disease development process dopamine is converted into a highly toxic chemical called DOPAL. This chemical, DOPAL, causes the clumping of alpha-synuclein protein in the brain. This triggers the death of dopamine-producing cells, ultimately leading to Parkinson’s. Read the full story here.

via: ScienceDaily


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A recent finding published in the journal Nature Chemical Biology reports the synthesis of a carbohydrate-based vaccine for cancer. The study carried out in mice demonstrated that the vaccine triggers a strong immune response to cancer cells. The vaccine has been created synthetically and has shown promising results in creating an antibody response that can kill cultured epithelial cells derived from mice. The results are highly encouraging and “astounding”. However, Geert-Jan Boons, Franklin professor of chemistry and the lead author cautions, “There’s a very big step going from mice to humans,”. Read the full story here.

via: Physorg


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