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.     

Effect of methylation to an ethylenediamine receptor-based fluorescence signaling system: Solvent dependence, metal ion selectivity and photophysical studies

A fluorescence signaling system (L₁) has been synthesized in the format, ‘fluorophore-spacer-receptor’ with an ‘amino-alkyl-amino’ group as the receptor where an anthracene and a 2,4-dinitrobenzene moieties are attached at two ends. As evident from the photophysical behavior of this system, attachment of methyl groups to the donor N atoms not only increases the charge-transfer character of the signaling system, but imparts structural rigidity and perturbs the binding ability of the receptor core, that results in selective fluorescence enhancement in presence of Zn(II). Solid-state structure of L₁ is determined by X-ray crystallography.     

Biomimetic multifunctional porous chalcogels as solar fuel catalysts

Biological systems that can capture and store solar energy are rich in a variety of chemical functionalities, incorporating light-harvesting components, electron-transfer cofactors, and redox-active catalysts into one supramolecule. Any artificial mimic of such systems designed for solar fuels production will require the integration of complex subunits into a larger architecture. We present porous chalcogenide frameworks that can contain both immobilized redox-active Fe(4)S(4) clusters and light-harvesting photoredox dye molecules in close proximity. These multifunctional gels are shown to electrocatalytically reduce protons and carbon disulfide. In addition, incorporation of a photoredox agent into the chalcogels is shown to photochemically produce hydrogen. The gels have a high degree of synthetic flexibility, which should allow for a wide range of light-driven processes relevant to the production of solar fuels.     

The role of interplay between the potential and the ambient energies on the vibration energy harvesting

In this paper we have demonstrated how the conversion of the ambient energy into the electrical energy depends on the properties of the ambient energy and the mechanical oscillator. We have observed that the conversion of the vibration energy into the electrical energy may be good if the voltage can follow closely the evolution of of the amplitude of the oscillator. Thus if the voltage and the position fluctuate in a correlated manner then the conversion of the ambient energy into the electrical energy is good. Our another observation is that for a given capacitance, the power transferred (PT) from the oscillator to the transducer may be maximum in the variation of PT with increase in resistance, R. In other words, the power transferred changes with a maximum as the capacitance, C grows for a fixed value of the resistance. Along with these we have investigated how the other relevant quantities such as the efficiency of the energy transferred process depends on the characteristics of the oscillating systems, the environment and the piezoelectric dynamics.     

Noise correlation-induced splitting of Kramers' escape rate from a metastable state

A correlation between two noise processes driving the thermally activated particles in a symmetric triple-well potential may cause a symmetry breaking and a difference in relative stability of the two side wells with respect to the middle one. This leads to an asymmetric localization of population and splitting of Kramers' rate of escape from the middle well, ensuring a preferential distribution of the products in the course of a parallel reaction.     

Self‐assembly of Renewable Nano‐sized Triterpenoids

Studies on plant metabolites have gained renewed interest in recent years because these can serve as renewable chemicals for the development of a sustainable society. Among various plant secondary metabolites, terpenoids constitute the major component and triterpenoids are the 30C subset of it. In recent years, triterpenoids have drawn the attention of scientific community due to many of its potential and realized applications in medicine, drug delivery, thermochromic materials, pollutant capture, catalysis, liquid crystals, etc. In this personal review, we have discussed our computational results carried out on sixty representative naturally occurring triterpenoids demonstrating that all the triterpenoids are renewable functional nano‐entities. Study of the self‐assembly of several triterpenoids such as betulin, betulinic acid, oleanolic acid, glycyrrhetinic acid and arjunolic acid and their derivatives in different liquids have also been discussed. Moreover, the utilization of the resulting supramolecular architectures such as vesicles, spheres, flowers and fibrillar networks of nano‐ to micrometer dimensions and gels have also been discussed in the perspective of green, renewable and nanos.     

Colored multiplicative and additive non-Gaussian noise-driven dynamical system: Mean first passage time

We have studied the barrier crossing dynamics in presence of non-Gaussian noises. It has been observed that multiplicative colored non-Gaussian noise can induce resonant activation (RA). The conspicuous dependence of mean first passage time (MFPT) on correlation time (_τ2${\tau }_2$) of additive colored noise having fixed variance have been analyzed. Beyond a critical value of _τ2${\tau }_2$ the MFPT increases for a given rate of increase of noise strength with _τ2${\tau }_2$ if the additive colored noise is non-Gaussian. The MFPT first decreases with increase of the non-Gaussian parameter (measures deviation from Gaussian character) of multiplicative colored noise followed by an increase exhibiting a minimum. The appearance of the minimum critically depends on the additive noise.