ISA

006073 Shakibaie M R;Jalilzadeh K A;Yamakanamardi S M (Microbiology Dep, Kerman University of Medical Sciences, Kerman-475 6025, Iran) : Horizontal transfer of antibiotic resistance genes among gram negative bacteria in sewage and lake water and influence of some physico-chemcal parameters of water on conjugation process. J envir Biol 2009, 30(1), 45-9.

Transfer of antibiotic resistance genes among gram negative bacteria in sewage and lake water and easy access of these bacteria to the community are major environmental and public health concern. The aim of the study was to determine transfer of the antimicrobial resistance genes from resistant to susceptible gram negative bacteria in the sewage and lake water by conjugation process and to determine the influence of some physico-chemical parameters of sewage and lake water on the transfer of these resistance genes. For this reason, authors isolated 20 liter of each sewage and lake water from coconut area within university campus and Lingambudi lake respectively in Mysore city, India, during monsoon season and studied different physical parameters of the water samples like pH, temperature, conductivity, turbidity and color as well as chemical parameters like BOD, COD, field DO and total chloride ion. The gram negative bacteria were isolated and identified from the above water samples using microbiological and biochemical methods and their sensitivity to different antibiotics was determined by disc diffusion break point assay. Conjugation between two multiple antibiotic resistant isolates Pseudomonas aeuginosa and E.coli as donor and E.coli Rif^{r (sensitive to antibiotics) as recipient were carried out in 5ml sterile sewage and lake water. All isolates were resistant to Am, moderately resistant to Te and E, while majority were sensitive to Cip, Gm and CAZ antibiotics. Horizontal transfer of antibiotic resistance genes by conjugation process revealed transfer of Gm, Te and E resistant genes from Ps. aeruginosa to E.coli Rif^{r recipient with mean frequency of ± 2.3 x 10^{-4 in sewage and ± 2.6 x 10^{-6 in lake water respectively. Frequency of conjugation in sewage was two fold more as compared to lake water (p≤0.05). Co-transfer study revealed simultaneous transfer of above resistant markers together to the recipient cells. As the above results indicate, due to selective pressure in sewage (presence of antibiotics), the isolates from sewage were more resistant to different antibiotics as compared to those from lake water. Furthermore, these resistance genes can transfer to sensitive bacteria by conjugation. Physico-chemical parameters of water may play role in this process.}}}}

2 illus, 3 tables, 19 ref

Effect of cadmium in the histology of gill of estuarine clam Meretrix casta

Saravanan K;Subramanian R

Occurrence of organochlorine pesticides residue in Kuano river of eastern Uttar Pradesh

Sandeep Singh;Mishra R N

Environmental economics and market based instruments

Ranganathan V

Physico-chemical characteristics of carpet industries effluents, Bhadohi, Sant Ravidas Nagar

Rai K;Siddiqui K A

Characterization of protein content of shelled Moringa oleifera seedsused for decontmination of arsenic from water bodies

Pushpa Kumari;Srivastava M M

Risk assessment of the amnesic shellfish poison, domoic acid on animals and humans

Prem Kumar K;Prem Kumar S;Achuthan Nair G

006067 Prem Kumar K;Prem Kumar S;Achuthan Nair G (NO, ENBIOMON, 1205 Seaton et, Montgomery, Alabama-36117, USA) : Risk assessment of the amnesic shellfish poison, domoic acid on animals and humans. J envir Biol 2009, 30(3), 319-25.

Risk assessment of the amnesic shellfish poison, domoic acid, a potent neurotoxin, is evaluated based on its current knowledge and its harmful effects, and is presented under four headings, viz., (1) hazard identification, (2) dose response assessment, (3) exposure assessment and (4) risk characterization. Domoic acid binds the glutamate receptor site of the central nervous system (CNS) of humans and causes depolarization of neurons and an increase in cellular calcium. In nature, domoic acid is produced by the algae, Pseudonitzschia spp. and they enter into the body of shellfish through their consumption. This toxin is reported to cause gastroenteritis, renal insufficiency, confusion and memory loss in humans, since it affects the hippocampus of the brain. In rats, intraperitonial and oral administration of domoic acid result in scratching, tremor and convulsions, and in monkeys, the toxic symptoms like mastication, salivation, projectile vomiting, weakness, teeth grinding and lethargy are apparent. The no-observed-adverse-effect-level (NOAEL) in animals reveals that pure toxin is more effective than those isolated from shellfish. Based on LD₅₀ values, it is found that intraperitonial administration of this toxin in animals is 31 fold more effective than oral administration. Low levels of domoic acid (0.20 - 0.75 ppm) show no toxic symptoms in non-human primates, but clinical effects are apparent in them and in humans, at a concentration of 1.0 ppm. The tolerable daily intake (TDI) of domoic acid for humans is calculated as 0.075 ppm, whereas for razor clams and crabs, the TDI are 19.4 and 31.5 ppm respectively. The hazard quotient (HQ) is found to be 2. Being an irreversible neurotoxin, domoic acid has severe public health implications. Death occurs in those above 68 years old. In order to ensure adequate protection to public health, the concentration of domoic acid in shellfish and shellfish parts at point of sale shall not exceed the current permissible limit of 20 mg g^-1 tissue. While processing shellfish, it may be advisable to pay attention to factors such as environmental conditions, inter-organ variability in concentrations of domoic acid and cross contaminations.

^iia2 tabels, 54 ref

Heavy metals of packaged drinking water in indore city (M.P.)

Prajapati R;Choudhary S