This decade has already witnessed several successful applications of stem cell therapy for a few diseases. Next decade will see the application of stem cell therapy to many more genetic disorders and also for the repair of damaged tissues which cannot be repaired successfully by conventional procedures. A case in point is repairing damaged cardiac tissue and vascular tissue. In the article, "Prospects of a Progenitor Cell: A Special Focus on Endothelial Progenitor Cells (EPCs)", the authors, Abel Arul Nathan and Madhulika Dixit, have lucidly analyzed the historical background and described how vascular progenitor cells could be used to regenerate damaged vascular tissues. They have also emphasized the need to have standardized protocols to harness the study and induce the endothelial progenitor cells to differentiate into vascular endothelium. There is also a need to explore other applications for these endothelial progenitor cells.

Several generations of vaccines have been developed against several diseases and the DNA vaccines are considered as the latest armor to protect ourselves against certain diseases. DNA vaccine may not only provide an answer to some vaccines which have failed but also help to develop vaccine for some diseases for which no vaccine exists. It is possible that a DNA vaccine for tuberculosis when developed will provide lifelong protection, unlike the existing BCG vaccine which has been found to be effective only in children. DNA vaccine for rabies has already been developed for animals and is in advanced phase of clinical trial now. In the article, "Recombinant DNA Vaccines: Present Status and Future Perspective", the authors, Nishant Rai, Harish Chandra, Jatin Srivastava, Sachin Chauhan and A R Nautiyal, have traced the history of vaccines and have presented an update on the DNA vaccines.

The article, "Association Between Antibiotic Resistance and Metal Tolerance in Bacteria: A Recent Report", by M K Chattopadhyay, highlights the consequences of unmindful, generous use of antibiotics in animal feed for various reasons. This results in the selection of antibiotic resistance in the intestinal microorganisms of cattle which eventually reach the soil and water. These bacteria serve as reservoirs for the drug resistance genes and may be responsible for the antibiotic resistance observed in human hosts. Microorganisms isolated from river water in India and China and those isolated from Antarctica have shown resistance to several antibiotics. The author shows that the resistance to heavy metals and antibiotic resistance coexist in several microorganisms and these genes could spread across species through fish, cattle, water, etc. Hence, utmost care and restraint have to be exercised in using antibiotics in animal feed and aquaculture, as it poses a serious public health problem.

The human genome project has helped to unravel several mysteries of life and living organisms. Yet there are several mechanisms (mysteries) which we do not fully understand. One such phenomenon is wobbling which occurs during the binding of the codon and anticodon. We know how this wobbling helps to economize the codon usage during transcription, but we still do not understand exactly how it occurs. Badrinath Dubey, Alak Kumar Buragohain and Suvendra Kumar Ray, in their article, "Positive Correlation of Bacterial Genome GC% with the Number of Different Anticodons Used by the Genome to Decode All the Codons", have analyzed codon usuage, GC content and the distribution of tRNA genes for the amino acids in several microorganisms and describe that there is a strong correlation between the genome GC% and the codon/anticodon usage. This underscores an evolutionary implication and may help in understanding the differences in the rate of translation process.

Estrogen is a steroid hormone directly related to fertility in animals and humans. Phytoestrogens are a class of compounds of plant origin which closely resemble estrogen in structure and also bind to the estrogens` receptors. These phytoestrogens cause detrimental or beneficial effects in the host. The article, "Phytoestrogens: An Overview", by Jazir Haneef and S Sreeja describes various plant sources, the mechanism of action of phytoestrogens, and their effect on different target tissues and hosts. They inhibit hormone independent cancer by various mechanisms like inhibition of topo isomerases, angiogenesis, induction of differentiation in cancer cells and induction of apoptosis. In hormone-dependent cancers they exert their inhibition by reducing production of estrogen and by reducing the production of genotoxic estrogen metabolites. The beneficial effects of dietary phytoestrogens have also been demonstrated in osteoporosis in women. The phytoestrogens continue to be evaluated for their effect in various physiological and pathological conditions.

B V Bhaskara Reddy and Y S Ahlawat have reported a non-radio active method, which is affordable and reliable for detecting Citrus Mosaic Virus (CMV) is plant material, in their research note, "Comparative Detection of Citrus Yellow Mosaic Virus by Nucleic Acid Hybridization Using Radioactive and Non-Radioactive Probes". CMV is a DNA virus and is responsible for considerable damage to citrus crops all over the world, including India. The authors of this report have developed a DNA probe-based method for detecting the viral DNA from the leaves of the infected plant. A 2 kb citrus viral insert was released from its clone by restriction digestion. The virus-specific fragment was labelled with radioactive nucleotides by random priming and also directly with non-radioactive nucleotides. The labelling efficiency and sensitivity of detection of these two methods were found to be compatible.

Oxidation of membrane lipids damages the cell's integrity and causes lysis of cells. This may result in inflammation, accumulation of dead cells, etc. Oxidation is also believed to be a reason for aging. Antioxidant drugs top the list of blockbuster sales for many pharmaceutical companies, and there is a continuous effort to find new antioxidant drugs and new sources for antioxidants as dietary supplement. Phytochemicals are good candidates to supply antioxidants to our body. The research note, "Antioxidant Potential of Aqueous and Ethanolic Extracts of Brassica oleracea Var. capitata", by Wilfred A, Akshatha A, Harish R and Jyothi Bala Chauhan describes the extraction of active principle in ethanol and water and demonstration of the antioxidant property in both the extracts.

- - V Sritharan
Consulting Editor