Identification of Putative Vaccine and Drug Targets against the Methicillin-Resistant Staphylococcus aureus by Reverse Vaccinology and Subtractive Genomics Approaches

Methicillin-resistant Staphylococcus aureus (MRSA) is an opportunistic pathogen and responsible for causing life-threatening infections. The emergence of hypervirulent and multidrug-resistant (MDR) S. aureus strains led to challenging issues in antibiotic therapy. Consequently, the morbidity and mortality rates caused by S. aureus infections have a substantial impact on health concerns. The current worldwide prevalence of MRSA infections highlights the need for long-lasting preventive measures and strategies. Unfortunately, effective measures are limited. In this study, we focus on the identification of vaccine candidates and drug target proteins against the 16 strains of MRSA using reverse vaccinology and subtractive genomics approaches. Using the reverse vaccinology approach, 4 putative antigenic proteins were identified; among these, PrsA and EssA proteins were found to be more promising vaccine candidates. We applied a molecular docking approach of selected 8 drug target proteins with the drug-like molecules, revealing that the ZINC4235426 as potential drug molecule with favorable interactions with the target active site residues of 5 drug target proteins viz., biotin protein ligase, HPr kinase/phosphorylase, thymidylate kinase, UDP-N-acetylmuramoyl-L-alanyl-D-glutamate-L-lysine ligase, and pantothenate synthetase. Thus, the identified proteins can be used for further rational drug or vaccine design to identify novel therapeutic agents for the treatment of multidrug-resistant staphylococcal infection.     

New peroxovanadium compounds containing biogenic co-ligands: synthesis,stability and effect on alkaline phosphatase activity

A set of new diperoxovanadate(V) complexes with the dipeptides glycyl–glycine or glycyl–leucine as ancillary ligands of the type, A[VO(O₂)₂(peptide)(H₂O)] · H₂O, A = Na or K have been synthesized and characterized by elemental analysis, thermal analysis, magnetic susceptibility and spectral studies. The complexes contain side-on bound peroxo groups and a dipeptide zwitterion as co-ligand, binding the metal center unidentately through O (carboxylate) atom. The compounds are highly stable toward decomposition in solutions of acidic as well as physiological pH and serve as weak substrates to catalase, undergoing degradation in the presence of the enzyme at a rate much slower than H₂O₂. The compounds stoichiometrically oxidize GSH to GSSG. On comparing the GSH oxidizing ability of these compounds with those of previously reported peroxotungsten compounds containing similar co-ligands, a significant difference was noted. The compounds induce a strong inhibitory effect on alkaline phosphatase activity with a potency higher than that of the free peptides, vanadate, or peroxovanadate.     

An analysis of lasing without inversion in a three level system in terms of vector representation

In the present work we have worked out phasor diagrams with the help of the concept of moving vectors. We show that the area enclosed by the phasor diagrams behaves like lifetime of atomic states. We also make a comparative study of our model with the models suggested by other workers to explain lasing without inversion.     

Study of Complex Coacervation of Gelatin A and Sodium Alginate for Microencapsulation of Olive Oil

Complex coacervation of gelatin A and sodium alginate was carried out to obtain the maximum coacervate yield. Turbidity and coacervate yield (%) measurements were carried out to support the ratio of the two polymers and pH that produced maximum coacervation. The optimum ratio between gelatin A-sodium alginate and pH to form the maximum coacervate complex was found to be 3.5:1 and 3.5–3.8, respectively. Olive oil microencapsulation was carried out at the optimized ratio and pH. Microcapsules were crosslinked by using glutaraldehyde. Scanning electron microscopy studies confirmed the formation of free flowing spherical microcapsules of different sizes. The size of microcapsules increased with the increase in the concentration of the polymer. The encapsulation efficiency and the release rates of olive oil were dependent on the amount of crosslinker, oil loading and polymer concentration. Thermogravimetric study revealed improvement of thermal stability with crosslinking. Fourier Transform Infrared Spectroscopy study showed that there was no significant interaction between olive oil and gelatin-alginate complex.     

Effect of Association of Curcumin with Chitosan in Presence of TX 100 on Its Degradation

The binding of curcumin with chitosan in the presence of nonionic surfactant, iso-octylphenoxy-polyethoxy-ethanol (Triton X-100) and its stability in such systems have been investigated by monitoring the changes in the absorption spectra at physiological pH (7.4). It was observed that curcumin binds to chitosan more than 10 times stronger in presence of TX 100 at the experimental condition. From spectrophotometric analysis of the kinetics of degradation of the dye, it was observed that the yield of suppression of degradation of curcumin by chitosan increases by 33.5% in the presence of TX 100 than alone. The interaction of the dye with chitosan has been found to be exothermic and driven by hydrophobic interactions, hydrogen bond formation, and electrostatic interactions.