Many regions of the world are facing the problem with arsenic toxicity. Arsenic contamination has become a considerable threat to the environment triggering various big health issues for every life in that contaminated environment. Lysinibacillus sphaericus (B1-CDA) is an arsenic tolerant strain of bacteria that has been reported and characterized before by the researchers of the University of Skövde, Sweden. The bacteria were found to contain many arsenic responsive genes such as arsB, arsC, and arsR which are responsible for arsenic tolerance in the bacterium. The main focus of the current study was to characterize one of the arsB genes (gene-4251) of Lysinibacillus sphaericus B1-CDA by in silico and in vitro analyses in order to determine the molecular function of this gene. The in silico studies conducted by using the Iterative Threading Assembly and Refinement (I-TASSER) server predicted the tertiary structure of the ArsB protein and suggested that this protein is an intrinsic component of the membrane which primarily helps in the binding of metal ions and liberation of metabolic energy. To validate this predictive results, several in vitro experiments were performed. For complementation studies, the arsB gene was cloned from L. sphaericus B1-CDA and transferred to an arsB knock-out mutant of Escherichia coli JW3469-1. Both, the transgenic and mutant strains were grown under the arsenic stress of 50 mM for 96 hrs followed by measuring their growth and arsenic tolerance after every 24 hrs. Statistical analysis confirmed that there was a significant difference in growth between the transgenic and the mutant E. coli strains. The ICP-MS (Inductive Coupled Plasma-Mass Spectroscopy) analysis revealed that after 24 hrs of culture, the arsenic content in the cell-free broth of transgenic strain was reduced from 50 mM to 9.10 mM (81.8%), whereas the reduction in arsenic content by the mutant strain was from 50 mM to 9.80 mM (80.2%). These results suggest that the arsB gene is partly involved in the accumulation of arsenic inside the cells and this feature could be used for a large scale removal of arsenic from the contaminated environment.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:his-15287 |
| Date | January 2017 |
| Creators | Borghate, Vedant Subhash |
| Publisher | Högskolan i Skövde, Institutionen för biovetenskap |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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