Recombinant DNA laboratory r DNA The Molecules which

Recombinant DNA laboratory • r. DNA: The Molecules which are constructed outside living cells by joining natural or synthetic DNA segments to DNA molecule that can replicate in a living cell

Risk assessment of r. DNA • There are 4 risk groups (RGs) • RG 1. The agents not associated with disease in healthy adult humans • RG 2. agents associated with human disease but not serious and therapies are available. • RG 3. sgents which are associated with serious human diseases for which prevention may be available • RG 4. agents which cause serious and lethal diseases in humans for which prevention and cure is not available

Experiments of r. DNA There should ask the local authority a permission before the initiation of research. Ø Experiments that require biosafety commmittee approval before initiation Ø Experiments using RGs groups 2, 3, 4 or restricted agents as host-vector systems Ø Experiments involving pathogenic infectious bacteria and viruses Ø Experiments involving whole plants and animals genomes to be altered

Risk Assessment of r. DNA Experiments 1) One of the worries early in the history of r. DNA technology was that a harmless microorganism could become pathogenic. 2) Another concern was that an individual or animal would become colonized with a recombinant organism producing a hormone or other pharmacologically active substance. It was calculated that even if one's intestines were completely colonized by E. coli K-12, producing insulin, human growth hormone, or interferon and these proteins were not digested, the quantities produced would be too low to have any effect. 3) A final concern is possible escape of a recombinant organism and subsequent disturbance of the environment.

Risk assessment Factors When risk assessment data for r. DNA experiments carried out following factors should be considered. • Virulence • Pathogenicity • Infectious dose • Environmental stability • Route of spread • Availability of vaccines or treatment • Gene product effects (Toxicity, Physiological activity and Allergenicity)

Biohazards of r. DNA • Pathogenic agents (bacteria, rickettsia, fungi, viruses, protozoa, parasites, prions. • Plants, animals or derived waste which contain or may contain pathogenic hazards (including xenotransplantation tissue). • Human and nonhuman primate tissue, body fluid (blood), organs and cell culture. • Other animal tissues and body fluids, flies, birds animals can transmit pathogens

Safety practices 1) 2) 3) 4) 5) 6) 7) 8) Laboratory line of authority should be available Spills and emergencies involving chemically dangerous materials which is immediately dangerous to life and health (IDLH) should be treated carefully Emergency equipments and Evacuation should be available and known Generation of aerosols should be stopped Infectious wastes should be decontaminated before disposal Shipping biological materials such as human or animals infectious agents or diagnostic/clinical samples cause dangerous risks should be identified and documented by trained persons GMOS should be released after strict analysis and regulations Lab safety cabinets with filters and ultraviolet lights (A biocidal device) should be used

Decontamination (1)Disinfectants • • Whenever possible, decontamination should be achieved by sterilisation in an autoclave (steam heat under pressure). Disinfectants should only be utilised where sterilisation is not possible e. g. large spaces, surfaces and delicate instruments. Disinfectants should be chosen on their effectiveness to deal with the specific type of micro-organism. The main uses for disinfectants are: washing - discarded containers, re-useable pipettes etc; wiping down benches and work surfaces at end of day; regular cleaning of equipment - water baths, incubators, centrifuges, freezers, refrigerators. The following are some commonly used disinfectants: Ethyl or isopropyl alcohol - 80% aqueous solution; Chlorine as hypochlorite solution; Iodine in aqueous or alcoholic solution (FORMALIN); Phenolic disinfectants - Lysol, Chloroxylenol. (2)Sterilisation • • • Steam heat autoclaves are utilised for sterilisation. Only properly trained staff should use the autoclave and care must be taken to ensure the load reaches the required temperature and remains at that temperature for the prescribed time. Visual indicators such as Browne's tubes or heat sensitive autoclave tape should be used routinely. Monthly checks of sterilising efficiency should be carried out by using spore strips. Times for sterilisation must be determined according to the load. Minimum sterilisation times after attainment of the required temperature are: 15 minutes at 121 o. C 2 minutes at 132 o. C