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The development of a country depends very much on the advancement of its industrialization. However, as a result of mass scale industrialization, the world's environment is being polluted day by day and endangering the existence of living beings on Earth. This has attracted the attention of environmental engineers, medical practitioners, planners, and researchers throughout the world. Attempts are being made to make air, water, and the atmosphere clean and to prevent likely hazards arising out of various industrial activities. In addition, radiation from natural sources is all around us and has been from the advent of time. It is responsible for the radiation exposure of most of the population. Coal miners have small occupational exposures that arise from naturally occurring radioactive substances under ground. The predominant source of natural radiation present in coal mines is radon gas. This article describes the origin of radon, radiological hazard, and an attempt has been made to review the status of the problem likely to be caused by the different radioactive elements present in Indian coal and coal ash and allied coal-based industries.

Carbamoyl-phosphate synthetase (CPSase) consists of a 120-kDa synthetase domain (CPS) that makes carbamoyl phosphate from ATP, bicarbonate, and ammonia usually produced by a separate glutaminase domain. CPS is composed of two subdomains, CPS.A and CPS.B. Although CPS.A and CPS.B have specialized functions in intact CPSase, the separately cloned subdomains can catalyze carbamoyl phosphate synthesis. This report describes the construction of a 58-kDa chimeric CPSase composed of Escherichia coli CPS.A catalytic subdomains and the mammalian regulatory subdomain. The catalytic parameters are similar to those of the E. coli enzyme, but the activity is regulated by the mammalian effectors and protein kinase A phosphorylation. The chimera has a single site that binds phosphoribosyl 5'-pyrophosphate (PRPP) with a dissociation constant of 25 microM. The dissociation constant for UTP of 0.23 mM was inferred from its effect on PRPP binding. Thus, the regulatory subdomain is an exchangeable ligand binding module that can control both CPS.A and CPS.B domains, and the pathway for allosteric signal transmission is identical in E. coli and mammalian CPSase. A deletion mutant that truncates the polypeptide within a postulated regulatory sequence is as active as the parent chimera but is insensitive to effectors. PRPP and UTP bind to the mutant, suggesting that the carboxyl half of the subdomain is essential for transmitting the allosteric signal but not for ligand binding.

Changes in the activities of two enzymes, viz., glutamic oxalacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) following exposure to the pyrethroids fenvalerate and decis (deltamethrin), the carbamate sevin (carbaryl), singly, and the binary mixtures of fenvalerate + sevin and decis + sevin was studied in the nervous tissue of the fresh water snail Lymnaea acuminata. The total amount of the pesticides administered in the binary mixtures was very low as compared to the amount contained in the 40% LC50 and 80% LC50 of any of the pesticides when given alone. On the one hand, lower quantities of pesticides were administered, while on the other, there was greater enhancement in the activities of the two transaminases. Thus, synergism in case of transaminase activity was much more as compared to synergism when lethality was taken as a criterion. The order of effectiveness of the pesticides/mixtures was decis + sevin > fenvalerate + sevin > decis > fenvalerate > sevin.