Comparative analysis of chromatin landscape in regulatory regions of human housekeeping and tissue specific genes

BACKGROUND: Global regulatory mechanisms involving chromatin assembly and remodelling in the promoter regions of genes is implicated in eukaryotic transcription control especially for genes subjected to spatial and temporal regulation. The potential to utilise global regulatory mechanisms for controlling gene expression might depend upon the architecture of the chromatin in and around the gene. In-silico analysis can yield important insights into this aspect, facilitating comparison of two or more classes of genes comprising of a large number of genes within each group. RESULTS: In the present study, we carried out a comparative analysis of chromatin characteristics in terms of the scaffold/matrix attachment regions, nucleosome formation potential and the occurrence of repetitive sequences, in the upstream regulatory regions of housekeeping and tissue specific genes. Our data show that putative scaffold/matrix attachment regions are more abundant and nucleosome formation potential is higher in the 5' regions of tissue specific genes as compared to the housekeeping genes. CONCLUSION: The differences in the chromatin features between the two groups of genes indicate the involvement of chromatin organisation in the control of gene expression. The presence of global regulatory mechanisms mediated through chromatin organisation can decrease the burden of invoking gene specific regulators for maintenance of the active/silenced state of gene expression. This could partially explain the lower number of genes estimated in the human genome

For the Pursuit of Excellence

36-37Hawking admired A.K. Raychaudhuri’s contributions to Physics. His contributions are widely recognized by the international scientific community. But AKR remains a hidden figure in his own homeland

Optimization of micro-injection molding process with respect to tensile properties of polypropylene

11-15An integrated optimization approach based on Box-Behnken design of experiment and response surface methodology of analysis has been used for optimization of micro-injection molding process with respect to the tensile properties of polypropylene dog-bone-shaped bars. It is found  that the response surface models of breaking strain and Young’s modulus developed by using this approach can satisfactorily predict the tensile properties of the polypropylene bars as a function of injection molding process parameters. The single and interaction effects of the injection molding process parameters are found to play significant roles in determining the tensile properties of the polypropylene bars

Structure and morphology of magnetron sputter deposited ultrathin ZnO films on confined polymeric template

The structure and morphology of ultra-thin zinc oxide (ZnO) films with different film thicknesses on confined polymer template were studied through X-ray reflectivity (XRR) and grazing incidence small angle X-ray scattering (GISAXS). Using magnetron sputter deposition technique ZnO thin films with different film thicknesses (<10 nm) were grown on confined polystyrene with $∼ 2R_g$ film thickness, where $R_g ∼$ 20 nm ($R_g$ is the unperturbed radius of gyration of polystyrene, defined by $R_g =$ 0.272 $√M_0$, and $M_0$ is the molecular weight of polystyrene). The detailed internal structure, along the surface/interfaces and the growth direction of the system were explored in this study, which provides insight into the growth procedure of ZnO on confined polymer and reveals that a thin layer of ZnO, with very low surface and interface roughness, can be grown by DC magnetron sputtering technique, with approximately full coverage (with bulk like electron density) even in nm order of thickness, in 2–7 nm range on confined polymer template, without disturbing the structure of the underneath template. The resulting ZnO-polystyrene hybrid systems show strong ZnO near band edge (NBE) and deep-level (DLE) emissions in their room temperature photoluminescence spectra, where the contribution of DLE gets relatively stronger with decreasing ZnO film thickness, indicating a significant enhancement of surface defects because of the greater surface to volume ratio in thinner films

Restricting Anion Migrations by Atomic Layer-Deposited Alumina on Perovskite Nanocrystals while Preserving Structural and Optical Properties

Lead halide perovskite (LHP) nanocrystals (NCs) offer an easy tunability of band gap via anion exchanges, enabling their usage in tandem optoelectronic devices with graded band gaps. However, instantaneous anion migrations at the interfaces of different LHP layers impede the formation of well-defined interfaces. We deposited an ultrathin alumina (Al2O3–x) layer at the interface of CsPbBr3–CsPbI3 NC films by using atomic layer deposition (ALD) and demonstrated that low-temperature ALD alumina has negligible impact on the structural or optical properties of CsPbBr3 NCs except agglomeration. ALD alumina can restrict anion migration for months but cannot be prevented permanently. The rate of anion migration significantly decreases with an increase in the Al2O3–x layer thickness on CsPbBr3 NC films, which follows first-order kinetics. Density functional theory (DFT) calculations showed that the iodide ion can migrate through oxygen vacancies in the Al2O3–x layer with an activation energy of 1.54 eV. This strategy provides new insight into fabricating halide perovskite-based tandem optoelectronics devices

Lipid from Infective L. donovani Regulates Acute Myeloid Cell Growth via Mitochondria Dependent MAPK Pathway

The microbial source, which includes live, attenuated, or genetically modified microbes or their cellular component(s) or metabolites, has gained increasing significance for therapeutic intervention against several pathophysiological conditions of disease including leukemia, which remains an incurable disease till now despite recent advances in the medical sciences. We therefore took up the present study to explore if the leishmanial lipid (pLLD) isolated from L. donovani can play an anti-neoplastic role in acute myeloid leukemia cells by regulating cellular growth. Indeed pLLD significantly inhibited cell proliferation of four AML cell lines (HL-60, MOLT-4, U937, and K562). Scanning electron microscopy and DNA fragmentation analysis revealed that it significantly induced apoptosis of U937 cells through morphological alteration. Occurrence of apoptosis was checked by using Annexin exposure and this established that the cell cycle was arrested at G0/G1 phase in time-dependent manner. pLLD increased the intracellular ROS with alteration of mitochondrial membrane potential, as detected using DCFDA. It also regulated the expression of apoptosis-related proteins like Bax, Bcl2, Bad and t-Bid besides causing cleavage of PARP as determined by western blot analysis. Treatment of U937 cells with pLLD induced the activation of extracellular signal-regulated kinase (ERK)1/2, c-Jun N-terminal kinase (JNK)1/2, p38, and caspases 9/3. The results suggest that pLLD induces apoptosis in acute myeloid leukemia cells possibly via increasing intracellular ROS and regulating the MAPK pathwa