Chitinolytic enzymes: an appraisal as a product of commercial potential.

Chitin, its deacetylated form, chitosan and chitinolytic enzymes viz. endo-chitinase, N-acetylglucosaminidase, chitosanase, chitin deacetylase (CDA) are gaining importance for their biotechnological applications. Presently, chitin degrading enzymes constitute high-cost low-volume products in human health care and associated research. Indeed chitinases and CDA-chitosanase complex possesss tremendous potential in agriculture to control plant pathogenic fungi and insects. The success in exploring chitinases especially for agriculture, i.e. as a high-volume low-cost product, depends on the availability of highly active preparations with a reasonable cost. Therefore, a reconsideration in terms of understanding the roles of chitinolytic enzymes in applications, e.g. host-pathogen interaction for biocontrol, different mechanisms of chitin degradation, and identification of new enzymes with varying specificities, may make them more useful in a variety of commercial processes in the near future. The possible issues and challenges encountered in the translation of proof of concept into a commercial product will be appraised in this review.

Geochronology of Pb and Hg pollution in a coastal marine environment using global fallout 137Cs.

Global fallout 137Cs was used for dating sediment cores and estimation of recent sedimentation rates (up to 1 cm/y) in the Thane Creek, which lies in the southern part of the Deccan belt of India. The residence time of 210Pb in the Thane Creek water was calculated to be 0.7 years. Further, the concentrations of Pb (up to 70 microg/g) and Hg (up to 10 microg/g) in sediment profiles were measured to assess the anthropogenic input of contaminants due to large-scale industrialization, which has taken place in this area over the last two decades. The depth-wise concentration profile of Hg shows positive evidence of continued fresh input into the Creek.

Behaviour and fluxes of trace and toxic elements in creek sediment near Mumbai, India.

Studies on marine sediments are extremely important since they act as ultimate sink of anthropogenic pollutants. The present study was conducted near Mumbai city of India to understand and assess the behaviour and fluxes of trace and toxic elements in creek sediment. Seven sediment core samples were collected and analysed for trace and toxic elements such as Fe, Cu, Pb, Zn, Rb and Sr in different sections of the core using EDXRF technique. The fluxes of the elements in each section of the core were calculated using the mass sedimentation rates derived from 210Pb dating technique and the sediment density at each location. The estimated depositional fluxes of Fe, Rb and Sr in Zone-1 and Zone-3 are in the ranges of 0.4-0.5% cm(-2) yr(-1); 4-6 microg cm(-2) yr(-1) and 10-20 microg cm(-2) yr(-1) respectively, where as they were about 3-4 times higher in zone-2 for the same elements. The depositional fluxes of elements Cu (40-60 microg cm(-2) yr(-1)), Zn (35-43 microg cm(-2) yr(-1)) and Pb (6-12 microg cm(-2) yr(-1)) were also found to be higher in zone-2 compared to zone-1 and zone-3 which can be attributed to the release from the newly developed chemical zone of Thane-Belapur industrial belt.

Heavy metal concentration and distribution in a dated sediment core of Nainital Lake in the Himalayan region.

The concentrations and distribution of the elements, including heavy metals such as As, Ba, Br, Co, Cr, Cs, Fe, Ga, K, Mn, Na, Rb, Sc, Sr, Th and Zn, were investigated in dated sediment cores of Nainital Lake located in the Himalayan region, in Uttar Pradesh state of India, which is considered as a remote background area. The concentrations of the elements were measured by instrumental neutron activation analysis using the k0 method. The International Atomic Energy Agency certified reference material SL-3 was used to evaluate the accuracy of the method. The normalized data for a series of elements were used to understand the source of loading. Elements like Br, Co, Cr, Fe, K, Mn and Zn show a negative correlation with increasing depth whereas elements like As, Ba, Cs, Na and Rb show a positive correlation with increasing depth. By considering the concentration for the bottom segments of the core as close to the baseline concentration, recent flux values for different elements were calculated. An increase in the flux value was observed for Br, Cr, Fe, K, Mn and Zn, which can be attributed to anthropogenic contribution in recent years.

Atmospheric dust loads and their elemental composition at a background site in India.

Air particulate samples collected during 1995-96 at a background site situated on the east coast of Thar Desert in Rajsthan State of India were analysed for atmospheric dust loads (Suspended Particulate Matter) and elemental composition. The values of SPM ranged from 9 microg M(-3) to 97 microg M(-3) with an average of 43 microg M(-3) except a few episodic values, which were 3 to 5 times higher than the average during summer months. The results for elemental composition of the particulate samples showed that the concentrations of anthropogenic toxic trace elements viz. Br, Cr, Pb, Sb, Se and Zn are lower by a factor of 2 to 10 as compared to urban areas. The high enrichment factors for anthropogenic elements viz. Br, Pb, Sb and Zn show an input from coal/wood fuel burning and vehicular pollution at the sampling site. The depletion of Si in SPM samples shows long distance transport of dust to the sampling site.

Population problem, a planner's view.

PIP: A matter that is seriously being debated in India is whether the policy of "the stick or the carrot" should be adopted for controlling population growth, i.e., whether the country should depend upon "incentives" or "disincentives" for bringing about wider acceptance of family planning. In this planner's view, this debate is a nonissue in India's social and political context. Due to the fact that a major part of the country's resources are preempted for investment in economically productive sectors, it is not possible to follow a too liberal policy of offering "carrots" or high cash incentives. The family planning program does not function in a vacuum and must be integrated with the national perspective plan and economic priorities. This does not mean that there is no scheme for enabling the poorer sections of the population to avail themselves of the benefit of family planning. Free clinical facilities and supply of contraceptives and easier access to clinical services is certainly not part of the "carrot." If free medical and child care are taken into account, the benefits are quite substantial. Financial incentives are also given to acceptors of sterilization and IUD to compensate them for loss of wages sustained during hospitalization and convalescence. Yet, any incentives that are offered can only be very selected and limited in scope due to the vast numbers of target couples. Regarding the policy of the "stick" or disincentives, there is little room for this form of policy in India's democratic system. Disincentives in the form of denial of food, clothing, shelter, and medical facilities are out of the question for nonacceptors of family planning since these form part of the basic human rights. Some selective disincentives for discouraging "improvement parenthood" could be used when such disincentives can be built into contractual benefits like service conditions of employees of government and the organized sector. What is needed in India is a balanced policy of both selective incentives and disincentives to the extent that they are consistent with the country's resources, plan priorities, democratic fabric, political system, and the Directive Principles of State Policy. The present strategy is to cover as many couples as possible by increasing the facilities for sterilization in the District and taluka hospitals and the primary health centers. The government has also decided to liberalize the rate of payments to the State governments on sterilization. Addition funds have been provided for incentives at higher rates to motivators. There are clear indications that the family planning program is being implemented more seriously now by most of the States since a favorable climate has been created for it.^ieng