Inhibition of Filamentous Thermosensitive Mutant-Z Protein in Bacillus subtilis by Cyanobacterial Bioactive Compounds

Antibiotic resistance is one of the major growing concerns for public health. Conventional antibiotics act on a few predefined targets and, with time, several bacteria have developed resistance against a large number of antibiotics. The WHO has suggested that antibiotic resistance is at a crisis stage and identification of new antibiotics and targets could be the only approach to bridge the gap. Filamentous Temperature Sensitive-Mutant Z (Fts-Z) is one of the promising and less explored antibiotic targets. It is a highly conserved protein and plays a key role in bacterial cell division by introducing a cytokinetic Z-ring formation. In the present article, the potential of over 165 cyanobacterial compounds with reported antibiotic activity against the catalytic core domain in the Fts-Z protein of the Bacillus subtilis was studied. The identified cyanobacterial compounds were screened using the GLIDE module of Maestro v-2019-2 followed by 100-ns molecular dynamics (MD) simulation. Ranking of the potential compound was performed using dock score and MMGBSA based free energy. The study reported that the docking score of aphanorphine (−6.010 Kcalmol⁻¹) and alpha-dimorphecolic acid (ADMA) (−6.574 Kcalmol⁻¹) showed significant role with respect to the reported potential inhibitor PC190723 (−4.135 Kcalmol⁻¹). A 100 ns MD simulation infers that Fts-Z ADMA complex has a stable conformation throughout the progress of the simulation. Both the compounds, i.e., ADMA and Aphanorphine, were further considered for In-vitro validation by performing anti-bacterial studies against B. subtilis by agar well diffusion method. The results obtained through In-vitro studies confirm that ADMA, a small molecule of cyanobacterial origin, is a potential compound with an antibacterial activity that may act by inhibiting the novel target Fts-Z and could be a great drug candidate for antibiotic development.     

Investigations of the first order magnetic phase transition in dysprosium

The first order magnetic phase transition in polycrystalline sample of dysprosium (Dy) has been investigated in detail by dc-resistance vs. temperature (R-T) measurements. Distinct signature of coexistence of two magnetically ordered phases (i.e. ferromagnetic and antiferromagnetic), originating as a result of the metastable behavior associated with the first order phase transition (FOPT) is found near 90 K. By successfully recording the minor hysteresis loops within the hysteretic R-T regime of Dy, a varying degree of phase coexistence in the FOPT is demonstrated.     

Reduction of wave function associated with electromagnetic fields for imaginary mass system to standard helicity representation of Lorentz group

Reduced expansions for electromagnetic fields associated with spin-1 particles of imaginary mass (tachyons) have been derived in terms of standard helicity representations of inhomogeneous Lorentz group. The effects of wave equation and reality condition on these reduced expansions to satisfy Maxwell’s field equations have been derived. The reduced expansions of charge and current source densities associated with these fields have also been derived and it has been shown that these fields cannot satisfy the Maxwell’s equations in the absence of both the current and charge source densities.     

Preparation of NiFe2O4 nanopowder via EDTA precursor and study of its properties

An ethylene diamine tetra acetic acid (EDTA) precursor-based chemical method is reported for preparing single-phase nickel ferrite (NiFe₂O₄) nanopowder. The synthesized powder was characterized by thermogravimetric analysis, differential scanning calorimetric analysis, X-ray diffraction, particle size analysis and scanning electron microscopy. DC electrical resistivity and magnetic property of the synthesized NiFe₂O₄ were measured by using a two-probe method and a vibrating sample magnetometer respectively. The DC resistivity behaviour of the NiFe₂O₄ nanopowder was correlated with the change of microstructure, during sintering. This EDTA precursor-based method is capable of producing nanostructured single-phase NiFe₂O₄ powder at a comparatively low calcination temperature and offers the potential of a simple and cost-effective route, including the preparation of other ferrite nanoparticles.     

Dual functional novel catalytic Cu1−xZrxFe2O4 (x=0, 0.5, 1) nanoparticles for synthesis of polysubstituted pyridines and sunlight‐driven degradation of methylene blue

The effect of varied zirconium content on the structural, morphological, magnetic, optical, thermal and catalytic properties of nanoparticles of the ferrite Cu_1 ? xZr_xFe₂O₄ (x = 0, 0.5, 1) was investigated. The mixed ferrite was synthesized by the auto‐combustion method using nitrates of respective metals and citric acid as a chelating agent. The as‐prepared nanoparticles showed dual benefits. They were employed as a heterogeneous catalyst for one‐pot synthesis of polysubstituted pyridine derivatives as well as for catalytic degradation of industrial waste dyes such as methylene blue (MB). The highlight of the research reported is the catalytic degradation of industrial waste (MB) with high efficiency in eluent of a wide range of pH (3–13). The proposed nanoparticles arguably offer certain great advantages that include: low cost, facile nature, anti‐leaching property, magnetic recoverability and recyclability. The characterization of the as‐synthesized nanoparticles was done using various techniques. The leaching study was carried out using inductively coupled plasma optical emission spectroscopy. The formation of organic products was confirmed using Fourier transform infrared and ¹H NMR spectroscopies and examination of degradation products of MB dye was carried out using mass spectrometry and UV–visible spectroscopy.     

Blue light emission and amplification in left-handed isotropic Metallo-Semiconductor Photonic Crystal

A new left-handed isotropic design of semiconductor Photonic Crystal with plasmonic (Aluminum) nanorod inclusion is analyzed and proposed to demonstrate All-Angle Negative Refraction (AANR) with blue light amplification. It is shown that the proposed structure provides negative real values of both permeability (μ) and permittivity (?) with extremely low imaginary values for visible light. Phase slope and phase velocity is shown to be negative for blue light for proposed left-handed structure. Index matched to the incident medium and compensated losses due the gain assistance lead the light amplification in the designed structure. Finite Difference Time Domain (FDTD) method is applied to study left-handed transmission and reflection properties. Extremely high Left-Handed Transmission Efficiency is calculated which is found to be more than 99% for the proposed structure. Fabrication tolerance with effect of change in plasmonic nanorod radius by ±10% is also analyzed. Further, left-handed transmission for blue light is confirmed by analyzing the far-field spectrums of the proposed structure obtained by employing 3D FDTD method. Demonstration and study of near-field and far-field resonance reveals the nano-photonic application potential of the proposed structure as directional optical nano-antenna, polarizer and filter.