Production of ampicillin through Escherichia coli NCIM 2563 immobilized and cross-linked in alginate beads.

6-Amino penicillanic acid (6-APA) was condensed with D-alpha-phenyl glycine chloride in presence of E. coli NCIM 2563 to form ampicillin. At pH 5, 30% of 6-APA was converted to ampicillin during 1 hr incubation. When E. coli cells were immobilized in calcium alginate beads, the activity remained unaffected even after six batches of bioconversion. Inclusion of glutaraldehyde as multifunctional cross-linking agent, improved the stability of the biocatalyst beads.

Acid phosphatase and lipid peroxidation in human cataractous lens epithelium.

The anterior lens epithelial cells undergo a variety of degenerative and proliferative changes during cataract formation. Acid phosphatase is primarily responsible for tissue regeneration and tissue repair. The lipid hydroperoxides that are obtained by lipid peroxidation of polysaturated or unsaturated fatty acids bring about deterioration of biological membranes at cellular and tissue levels. Acid phosphatase and lipid peroxidation activities were studied on the lens epithelial cells of nuclear cataract, posterior subcapsular cataract, mature cataract, and mixed cataract. Of these, mature cataractous lens epithelium showed maximum activity for acid phosphatase (516.83 moles of p-nitrophenol released/g lens epithelium) and maximum levels of lipid peroxidation (86.29 O.D./min/g lens epithelium). In contrast, mixed cataractous lens epithelium showed minimum activity of acid phosphatase (222.61 moles of p-nitrophenol released/g lens epithelium) and minimum levels of lipid peroxidation (54.23 O.D./min/g lens epithelium). From our study, we correlated the maximum activity of acid phosphatase in mature cataractous lens epithelium with the increased areas of superimposed cells associated with the formation of mature cataract. Likewise, the maximum levels of lipid peroxidation in mature cataractous lens epithelium was correlated with increased permeability of the plasma membrane. Conversely, the minimum levels of lipid peroxidation in mixed cataractous lens epithelium makes us presume that factors other than lipid peroxidation may also account for the formation of mixed type of cataract.