Chromium binding Bacillus cereus VITSH1-a promising candidate for heavy metal clean up.

Bacteria survive metal stress by several mechanisms and metal binding is one such mechanism which has been screened in the present study to investigate the survival strategies of metal resistant bacteria. The production of siderophores, a metal chelating agent, was detected by chrome azurol S agar assay. The changes in cell wall studied by analysing the peptidoglycan and teichoic acid content indicated an increase in the cell wall content. Evaluation of morphological and physiological alterations like cell size, granularity analysed by SEM and flow cytometry analysis revealed an increase in cell size and granularity respectively. The transformation of phosphates monitored by 31 P NMR analysis indicated the presence of inorganic phosphate. Based on the cell wall changes and the 31 P NMR analysis, the surface charge of the organism was studied by zeta potential which displayed a difference at pH7.

Protein profiling of metal-resistant Bacillus cereus VITSH1.

AIMS: The aim of the study was to investigate the proteomic changes and antioxidant enzyme activity in chromium-resistant Bacillus cereus VITSH1 in response to heavy metal toxicity. METHODS AND RESULTS: The variation in protein expression and antioxidant enzyme activity in the presence and absence of metal was studied in B. cereus VITSH1. The differentially expressed proteins in chromium-treated conditions were determined by SDS PAGE. The proteins involved in metal binding, protein biosynthesis, protein folding, energy metabolism and motility were identified by mass spectrometry coupled with bioinformatics search tools. The in gel assays for antioxidant enzymes indicated a change in their activity under metal stress conditions. CONCLUSIONS: The findings of this study suggest that the organism combats metal stress probably by restricting the entry of metal inside the cell. The role of the differentially expressed proteins clearly indicates that the first line of defence is to avoid the entry of metal into the cell either by possessing a modified outer membrane or by moving away from the toxicant. Further work on the identification of other proteins playing a role in resistance would help in integrating the available knowledge on the resistance mechanisms the organisms employ to combat toxicity. SIGNIFICANCE AND IMPACT OF THE STUDY: The proteomic changes in the metal-exposed bacteria would give an insight into the proteins involved in metal resistance mechanisms and thereby aid in the development of biosensor-based technology for heavy metal detection.

Perspectives on progressive strategies and recent trends in the production of recombinant human factor VIII.

Factor VIII (fVIII), a glycoprotein cofactor, plays a crucial role in the intrinsic blood coagulation pathway. As one of the most essential blood clotting factors known today, fVIII is the largest and most complex commercialized therapeutic protein used in the treatment of hemophilia A, an X-linked recessive disorder. Two lyophilized fVIII concentrates (viz., plasma fractionated and recombinant) are in use to treat hemorrhagic episodes in patients suffering with hemophilia A. Recombinant fVIII (rfVIII) products that are devoid of human and animal protein expressed in mammalian cells can be used as an alternative to plasma derived (pd) products fractionated from human blood. Although effective, the expression of rfVIII in heterologous mammalian expression systems at an industrial scale is complicated due to complex fVIII structure and non-human pattern of post-translational modifications, particularly glycosylation. Chinese hamster ovary (CHO) is the most commonly used host cell line for the production of various biotherapeutics. Product safety and adaptability to grow in suspension is the most desirable feature that makes CHO, a suitable host for rfVIII production. Even though the therapeutic and commercial application of rfVIII protein from CHO has increased extensively, further studies are required at cellular to bioprocess level to overcome the challenges in production, purification and processing. Efficient strategies are required to attain better products pertaining to the glycosylation path, productivity, stability, etc., to bring down the cost of expensive therapeutics like rfVIII that obviates these biotherapeutics affordable to common man. This review summarizes the various approaches and developments that have been in practice in fVIII production.