Extraction and Characterization of Lipopolysaccharide from Salmonella typhi

Abstract

There is no standard process available for high purity LPS isolation, and it may be appropriate to mix two purification steps. For Salmonella typhi LPS that were subjected to normal microbiological & biochemical screening protocols, updated phenol-water extraction protocol & non-phenolic extraction methods were also used in present research. Pellet of crude LPS obtained with wet weight was 2.0 gm. yield of LPS was more by hot phenol method 1.94 mg/ml as compared to non-phenolic method 0.40 mg/ml. relative purity of LPS obtained by hot phenol method was more as compared to non-phenolic method, as protein content was 23.60 mg/ml in LPS extracted from hot phenol method & 26.62 mg/ ml in LPS extracted from non-phenolic method. However, Nucleic acid contain was comparable in LPS extracted from both methods. Qualitative analysis showed ladder like bands of LPS extracted by hot phenol method as compared to single band obtained for LPS extracted by non-phenolic method. Findings of silver staining clearly revealed ladder pattern of multi-rung bands that are characteristics of smooth form of gram negative bacteria due to difference in length of carbohydrate chain of O-antigen component. In order to clarify diseased conditions & better work on LPS profiling, this research may be crucial to lead to more successful diagnosis and care.