Circulating nucleic acids (CNA) are present in small amounts in the plasma of healthy individuals. However, increased levels of plasma CNA have been reported in a number of clinical disorders like cancer, stroke, trauma, myocardial infarction, autoimmune disorders, and pregnancy-associated complications. CNA has received special attention because of its potential application as a non-invasive, rapid and sensitive tool for molecular diagnosis and monitoring of acute pathologies and the prenatal diagnosis of fetal genetic diseases. This review throws light on the current status of blood CNA as a diagnostic marker and its potential as a powerful tool in the future.

The interactions of a tetrapeptide, lysyltryptophylglycyllysine tert-butyl ester (KWGK), with synthetic double-stranded polynucleotides [poly(dA).poly(dT), poly[d(A-T)], poly(rA).poly(dT), and poly(rA).poly(rU)], Escherichia coli DNA, and single-stranded polynucleotides [poly(rA), poly(rU), poly(dA), and poly(dT)] were studied in a low-salt buffer by absorption and fluorescence spectroscopy. From fluorescence quenching data, we determined the two binding constants K1 and K2 of the two-step mechanism previously proposed for lysyltryptophyllysine binding to polynucleotides [Brun, F., Toulmé, J.J., & Hélène, C. (1975) Biochemistry 14, 558-563]. The first complex (PN)1 is purely due to electrostatic interactions between the lysyl residues and the phosphate groups. The second complex (PN)2 involves an additional stacking of the indole moiety of the tryptophyl residue with the bases (or base pairs) of the polynucleotide and is in equilibrium with (PN)1. K2 measures the ratio of the concentrations of stacked and unstacked complexes. The fluorescence decay of the tryptophyl residue in KWGK was not significantly different in the presence and in the absence of double-stranded polynucleotides in agreement with the previous model, which assumes total quenching of tryptophan fluorescence in complex (PN)2 and identical fluorescence characteristics for free KWGK and complex (PN)1. The stacking of the tryptophyl residue with A.T base pairs in alternating poly[d(A-T)] was found to be 10 times more efficient than that with nonalternating poly(dA).poly(dT). Among A-T-containing double-stranded polynucleotides, poly(rA).poly(dT) was found to be the most favorable for tryptophan stacking. A similar behavior was previously demonstrated for several intercalating agents such as ethidium bromide, propidium iodide, and daunomycin.(ABSTRACT TRUNCATED AT 250 WORDS)

In the recent past, Acinetobacter baumannii in hospitals has become increasingly resistant to a number of antibiotics including the latest carbapenems and this is of great concern. Here, for the first time, we report 2D-Differential In-Gel Electrophoresis (DIGE) analysis of outer membrane proteome of ATCC 19606 and carbapenem-resistant strain of A. baumannii. Using biological variance analysis (BVA), we identified 25 differentially expressed proteins with a fold difference >or=2; confidence >90% and statistical significance p

alpha-Chymotrypsin was immobilized on Eudragit S-100 via covalent coupling with 93% retention of proteolytic activity. The conjugate behaved as a smart biocatalyst and functioned as a pH-dependent reversibly soluble-insoluble biocatalyst. The pH optimum of chymotrypsin broadened on immobilization, and the immobilized preparation showed better stability at and above pH 6.5 as compared to the free enzyme. The immobilized enzyme showed a slight shift in the temperature optimum and enhanced thermal stability retaining 70% of its original activity after 1 h of exposure to 40 degrees C as compared to the 25% residual activity for the free enzyme under identical conditions. K(m) and V(max) values did not change on immobilization. Also, the immobilized preparation was quite stable to reuse, it retained almost 85% of its original activity even after a fifth precipitation cycle. UV spectroscopy and circular dichroism were used to probe structural changes in the enzyme upon immobilization.