Natalia Kurantowicz
Warsaw University of Life Science, Poland
Title: How graphene family materials affect Listeria monocytogenes and Salmonella enterica strains?
Submitted Date: 06/29/2015
Biography
Natalia Kurantowicz is absolvent of Microbiology and Business Management at Warsaw University of Life Science interested in nanotechnology, microbiology and new conception of crisis management in social media. She is a Ph.D. student at Warsaw University of Life Science and investigating nanoparticles impact on living organism like bacteria, rats etc.
Abstract
High thermal stability, high mechanical strength, relatively good bio-compatibility for humans resulted from carbon composite graphene-like structures capable of being an antibacterial agent. The study compared the toxicity of different forms of graphene family materials (GFM); pristine graphene (pG), graphene oxide (GO) and reduced graphene oxide (rGO) towards bacteria strains. The effect of three different GFMs on chosen food-borne bacteria strains: Gram-positive (G+) – Listeria monocytogenes, and Gram-negative (G-) – Salmonella enterica were examined. Results are a decreased number of bacterial colonies were observed in probes 250 μg/mL for all examined GFMs. Moreover, as low concentration of GO as 25 μg/mL caused a drop in the level of bacterial colonies as well and reduced growth by almost 100%. The shape and size of GFMs and their interactions towards bacteria strains were inspected by transmission electron microscope. Bacteria were aggregated and attached to GFMs. A strong affinity occurred between bacteria and edges of pG and rGO, while bacteria strains attached to GO nanoparticle surfaces. The present results indicate that GFM antibacterial activity causes mechanical damage of bacterial cell membranes by a direct contact of the bacteria with the extremely sharp edges of GFM with sp3-hybridized bonds. Based on the present results, we propose a three-step antimicrobial mechanism of GFM. It includes initial cell deposition on GFM (step 1), membrane stress and disruption caused by direct contact with sharp edges and bonds (step 2), and finally stimulated oxidation stress (step 3). The key difference between the chosen graphene materials is the bacterial cell deposition place. rnrn
Rajshree Singh
Shri Agrasen Girls College, India
Title: Assessment of metal pollutants and physico-chemical parameters of river water at Sarvamangla Nagar (Korba), Chhattisgarh and identification of potential bacteria for bio-remediating heavy metals
Submitted Date: 07/21/2015
Biography
Rajshree Singh, pursuing PhD from Dr. C V Raman University, Bilaspur, Chhattisgarh, India on topic entitled “Isolation and identification of bacteria intended for heavy metals remediation from industrial effluentsâ€. She is working as Assistant Professor in microbiology department, Shri Agrasen Girls College, Korba, Chhattisgarh. She has also having teaching experience of almost 5 years. She has published one paper and one review article accepted to be published in book chapter.
Abstract
One of the greatest concerns for the water consumers is quality of water as it was contaminated by various industrial effluents like heavy metals and pathogenic microorganisms. Pollution due to heavy metals pollution, pose severe threat to the biodiversity as they are non-degradable and persist for longer time in food chain thus effecting health of human. Korba, “The power hub†of Chhattisgarh, ranks 5th in the ‘critically polluted areas’ in India. The present study of Hasdeo river water at Sarvmangla Nagar (Korba) shows that the high concentration of heavy metals (greater than the permissible limit as per WHO guidelines) pollutant in the sediment of river water was observed. Level of Fe found to be highest (0.75 mg/l), followed by Pb (0.65 mg/l), Zn (0.25mg/l), Cd (0.21 mg/l), Cu (0.12 mg/l) and Mn (0.03 mg/l). Pb and Cd were causing serious health problem to the population who use the water for their daily needs. Analysis of physico-chemical properties of water samples Like BOD (5.7), COD (8.2), DO (12.7), pH (7.8) and temperature (22.7) were correlates the level of metal pollution of river water. Our study also focuses on isolation and identification of different bacterial species resistant to heavy metal present in the river Hasdeo which were identified as Coliforms, Pseudomonas Sps, Enterbacter Sps. and Bacillus Sps. We have also focus on enhancement of bio-remediation properties of these bacteria for more efficient removal of heavy metal by bio-flocculation and genetic modification.rnrn
