Bio Fabrication of Silver Nanoparticle from Argemone mexicana for the Control of Aedes albopictus and their Antimicrobial Activity.

BACKGROUND: Plant synthesized silver nanoparticles give rapid control on mosquito larvae of dengue vector, Aedes albopictus. AgNPs synthesized from the plant, Argemone mexicana for the control of larvae and these nanoparticles inhibit the growth of microbes are broad spectrum of nanoparticle activities. METHODS: Nanoparticles were subjected to analysis by UV-vis spectrophotometry, Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. Furthermore, laboratory evaluation of plant mediated nano-particle carried out lethal toxicity on Aedes albopictus. The characterization studies confirmed the spherical shape and size (5-50 nm) of silver nano-particles. RESULTS: The efficacy of AgNPs was tested at concentration of 2 to 10 ppm against L1 to L4 larval instar of A. albopictus. The LC50 followed by LC90 values were (L1) 5.24, 8.66; (L2) 5.56, 8.85; (L3) 6.20, 10.01 and (L4) 7.04, 10.92 at 10 ppm of silver nanoparticle, whereas LC50 (LC90) values of (L1) 7.63, 11.58; (L2) 8.17, 11.88; 8.80, 12.82 and 8.94, 12.26 at 10 ppm of plant extract alone treated larvae, respectively. The mortality rates were positively correlated with the concentration of AgNPs. Significant (P<0.05) high square value changes in the larval mortality were also recorded between the period of exposure against all larval instar of A. albopictus. Silver nanoparticles were also tested for antimicrobial activity and significant toxicity inhibition was observed against the gram positive microbes and it exhibited mild toxicity against P. aeroginosa. CONCLUSION: Plant, A. mexicana synthesized silver nano-particles are rapid and potential mosquito larvicidal as well as antimicrobial agents. Finding of our results support that silver nanoparticles can be prepared in a simple and cost-effective manner and are suitable for bio-formulation against mosquitoes and microbes.

DNA damage in viscose factory workers occupationally exposed to carbon di-sulfide using buccal cell comet assay

Aim: The most important industrial use of carbon disulfide (CS2) has been in the fabrication of regeneratedcellulose rayon by the viscose process and cellophane. CS2 leads to increased frequency of chromosomal aberrations in workers with occupational exposure to CS2. Methods: In the present study, the DNA damage was analyzed by using buccal cell comet assay for 30 viscose plant workers who are occupationally exposed to CS2 and 30 healthy individuals. Both groups were classified as smokers and non-smokers and only the experimental subjects were classified based on the exposure period. The data were analyzed statistically bythe Student’s t-test. Results: The results of this study showed increased levels of DNA damage among viscose plant workers. Conclusion: The habit of cigarette smoking among the viscose workers had a synergistic effect on inducing DNA damage.

Mixture of betel leaf, areca nut and tobacco chewing is a risk factor for cytogenetic damage in construction workers from south India

Aim: To determine the cytogenetic effect of betel leaf, areca nut and tobacco mixture usage among female construction workers in Tamilnadu, Southern India. Methods: Totally 236 buccal cells and blood samples were collected from 80 betel quid users and 76 users with tobacco snuffing habit which were compared with 80 healthy subjects. Peripheral blood leukocyte cultures were analyzed for chromosomal aberrations (CA) and exfoliated cells from the buccal mucosa were examined for micronucleus (MN). Results: Statistically significant (p<0.01) increase in CA and MN were observed in users with snuffing habit when compared to users without snuffing habit and controls as confirmed by chi-square test. Therefore, specific biomarkers on cytogenetic endpoints might help in planning precautionary measures to reduce oral cancer risks. Conclusions: The present study can be concluded that a mixture of betel quid, areca nut and tobacco chewing/snuffing is unsafe for oral health. The genotoxic effect of smokeless tobacco should be considered in addition to other known hazards for assessing health risks.

Cytogenetic damage in khaini users of Tamilnadu, Southern India

Aim: The smokeless tobacco (ST) has a strong association with the risk of oral leukoplakia (OL), oral submucous fibrosis (OSF) and oral cancer (OC). ST components exhibit genotoxicity and may alter the structure of DNA, proteins and lipids, resulting in the production of antigenicity. In this study, an attempt was made to estimate the cytogenetic damage [chromosomal aberrations (CA) and micronucleus (MN)] in people habituated to consume khaini (ST), which is one of the major forms of tobacco consumption in Tamilnadu, India, and believed to be a major risk factor for OC. Methods: After signing a consent form, volunteers provided blood samples (108 samples from including experimental and control subjects) to establish cell cultures at 52 h. For CA analysis, 100 complete metaphase cells per subject were evaluated. Chromatid- and chromosomal- type aberrations were identified in experimental and control subjects, where the latter showed a very minimal number of CA in age wise manner. Results: Statistically significant results were obtained in experimental subjects when compared to controls as confirmed by chi-square test. Exfoliated cells from the buccal mucosaof Khaini users were examined by using the micronucleus assay. The difference in mean micronucleated cell count for buccal mucosa between cases and controls were significant (p<0.01). Hence, specific biomarkers on cytogenetic endpoints might help in establishing preventive measures to reduce cancer risks. Conclusion: the genotoxic effect of smokeless tobacco should be considered in addition to other known hazards for assessing health risks.