title: Cadmium resistance in extremely halophilic archaeon Haloferax strain BBK2.
abstract: Halophilic archaea are prevalent in highly saline habitats. Haloferax strain BBK2 is an orange pigmented, exopolysaccharide (EPS) producing extremely halophilic archaeon, isolated from solar salterns of Ribandar, Goa, India. It grew in varying pH (5-10) and NaCl concentration (10-30%). The isolate grew well in complex (NTYE) and minimal media (NGSM) in presence of heavy metal cadmium (Cd) up to 4.0 mM (805.28 mg L(-1)) concentration. The optimum growth in the presence and absence of Cd was seen at a pH range of 7-9 and salinity of 15-25%. The growth kinetics of the isolate in NTYE showed a specific growth rate (μmax) of 0.352 with generation time of 1.968 days. In presence of 1mM Cd, the μmax was 0.325 day(-1) and generation time was 2.132 days. In NGSM, the μmax decreased from 0.517 day(-1) (in control) to 0.265 day(-1) in 1mM Cd while, the doubling time increased from 1.34 days in control to 2.615 days in presence of 1 mM Cd. SDS PAGE of the whole cell protein extracts showed overexpressed proteins of 74.14 and 40 kDa. The scanning electron microscopy, energy dispersive X-ray spectroscopy (SEM-EDX) analysis of the intact cells and cells disrupted by dialysis revealed that Cd was bound onto the cells, which was further confirmed by AAS, FTIR and XRD analysis.
authors.affiliation: Department of Biological Sciences, Birla Institute of Technology and Science Pilani, KK Birla Goa Campus, NH 17B Zuarinagar, Goa 403 726, India.
authors.forename: Deepthi
authors.initials: D
authors.lastname: Das
authors.affiliation: Department of Biological Sciences, Birla Institute of Technology and Science Pilani, KK Birla Goa Campus, NH 17B Zuarinagar, Goa 403 726, India.
authors.forename: Bhakti B
authors.initials: BB
authors.lastname: Salgaonkar
authors.affiliation: Department of Biological Sciences, Birla Institute of Technology and Science Pilani, KK Birla Goa Campus, NH 17B Zuarinagar, Goa 403 726, India.
authors.forename: Kabilan
authors.initials: K
authors.lastname: Mani
authors.affiliation: Department of Biological Sciences, Birla Institute of Technology and Science Pilani, KK Birla Goa Campus, NH 17B Zuarinagar, Goa 403 726, India. Electronic address: judith@goa.bits-pilani.ac.in.
authors.forename: Judith M
authors.initials: JM
authors.lastname: Braganca
mesh_terms: D002104:Cadmium / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D017753:Ecosystem; D019621:Haloferax / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology*; D007194:India; D054712:Salinity; D013052:Spectrometry, X-Ray Emission; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D002104:Cadmium
keywords: Growth; Haloarchaea; Metal tolerance; Resistance; Salinity