Purification,crystallization, and X-ray diffraction analysis of succinyl-diaminopimelate desuccinylase from Wolbachia endosymbiont of Brugia malayi

Lymphatic filariasis (LF) is a debilitating mosquito-borne parasitic disease caused by Brugia malayi in humans in the lymphatic system. Although limited drugs are available to treat this disease, these drugs are only effective against the larvae of Brugia malayi. As resistance has been reported to the available drugs, a new antifilarial drug is needed with better prognostic features, a short period of time of use, and efficiency at preventing adult worm survival. In this study, we have targeted succinyl-diaminopimelate desuccinylase (DapE) from the Wolbachia endosymbiont of Brugia malayi (WBm), which is involved in the production of lysine and meso-diaminopimelic acid, an essential component for the formation of bacterial cell walls, and plays a vital role in pathogen survival. Deletion of DapE gene is lethal to WBm since the organism has no alternative pathway for lysine biosynthesis. Here, the expression, purification, and crystallization of DapE are reported. The crystals of DapE, with an estimated solvent content of 50.76%, diffract synchrotron X-rays to a resolution of 2.3 Å and belong to the space group C222₁, with unit-cell parameters of a = 51.78, b = 78.83, and c = 216.20 Å. The X-ray absorption spectroscopy further confirms that zinc atoms are incorporated in DapE.     

Industrial cutting waste granite dust reinforced cardanol benzoxazine/epoxy resin hybrid composites for high-voltage electrical insulation applications

An attempt has been made to develop hybrid composites from benzoxazine monomer (C-ddm) hybridized with DGEBA epoxy resin (EP) and reinforced with varying weight percentages (20 wt%, 40 wt%, 60 wt%, 80 wt% and 100 wt%) of glycidoxypropyltrimethoxy- silane (GPTMS) functionalized granite dust (GD) obtained from industrial granite cutting and polishing process in order to utilize them for electrical insulation applications. The thermal stability of granite dust reinforced poly(EP-co-C-ddm) composites was studied by TGA analysis. Among the composites samples studied, 100 wt% GD reinforced poly(EP-co-C-ddm) composites possess better thermal stability than that of other neat matrices and composites. Among the composites prepared using varying weight percentages of functionalized GD reinforcement, it was observed that 80 wt% GD reinforced poly(EP-co-C-ddm) composites possesses better hydrophobic character than that of other neat matrices and composites. The value of LOI calculated for neat matrix (poly[EP-co-C-ddm]) and 20 wt%, 40 wt%, 60 wt%, 80 wt% and 100 wt% GD reinforced composites was found to be 22, 28, 34, 40, 43 and 45 respectively. The 80 wt% GD reinforced poly(EP-co-C-ddm) composites possess the higher values of tensile strength and flexural strength of 47 MPa and 140 MPa, respectively than those of their samples. The values of electrical surface resistivity and electrical volume resistivity of all the neat matrices and GD reinforced polybenzoxazine composites were found to be in the order of 10¹² and 10¹³ respectively. The values of dielectric strength obtained from break down voltage (BDV) for neat matrix [poly(EP-co-C-ddm)] and 20 wt%, 40 wt%, 60 wt%, 80 wt% and 100 wt% of GD reinforced poly(EP-co-C-ddm) composites are 15.0, 15.5, 16.5, 17.0, 17.0 and 17.0 kV/mm, respectively. Data obtained from thermal stability, hydrophobic behavior and dielectric studies it was inferred that the hybrid polymer composites developed in the present work can be conveniently used in the form insulators, sealants, adhesives and matrices where application demands at high-performance industrial and engineering applications.     

Experimental Determination of f″ for Ga and In From Bijvoet Ratio

The imaginary components of the anomalous dispersion correction terms for the heavy atoms gallium and indium, evcaluated from a systematic and precise experimetal measurement of the Bijvoet ratios for the spherically ground single crystals of GaP and InP, are reported. The procedure used is based on the work of Engel and Sturm who refined the crystal structures involving light atoms using anomalous scattering and employed the measured structure factors to evaluate the f″ values of the heavy atoms. In the present work, instead of refining the crystal structure, the structure factors are obtained using a refinement program. The experimentally evaluated f″ values are in very close agreement with the reported theoretical values.