Atomic fountain of laser-cooled Yb atoms for precision measurements

We demonstrate launching of laser-cooled Yb atoms in a cold atomic fountain. Atoms in a collimated thermal beam are first cooled and captured in a magneto-optic trap (MOT) operating on the strongly-allowed ${^1S}_0 \rightarrow {^1P}_1$ transition at 399~nm (blue line). They are then transferred to a MOT on the weakly-allowed ${^1S}_0 \rightarrow {^3P}_1$ transition at 556~nm (green line). Cold atoms from the green MOT are launched against gravity at a velocity of around 2.5~m/s using a pair of green beams. We trap more than $10^7$ atoms in the blue MOT and transfer up to 70\% into the green MOT. The temperature for the odd isotope, $^{171}$Yb, is $\sim$1~mK in the blue MOT, and reduces by a factor of 40 in the green MOT.Comment: 6 pages, 7 figure

Antisense expression of a gene encoding a calcium-binding protein in transgenic tobacco leads to altered morphology and enhanced chlorophyll

Entamoeba histolytica contains a novel calcium-binding protein like calmodulin, which was discovered earlier, and we have reported the presence of its homologue(s) and a dependent protein kinase in plants. To understand the functions of these in plants, a cDNA encoding a calcium-binding protein isolated from Entamoeba histolytica (EhCaBP) was cloned into vector pBI121 in antisense orientation and transgenic tobacco plants were raised. These plants showed variation in several phenotypic characters, of which two distinct features, more greenness and leaf thickness, were inherited in subsequent generations. The increase in the level of total chlorophyll in different plants ranged from 60% to 70%. There was no major change in chloroplast structure and in the protein level of D1, D2, LHCP and RuBP carboxylase. These morphological changes were not seen in antisense calmodulin transgenic tobacco plants, nor was the calmodulin level altered in EhCaBP antisense plants

Insertion of a small peptide of six amino acids into the β7–β8 loop of the p51 subunit of HIV-1 reverse transcriptase perturbs the heterodimer and affects its activities

BACKGROUND: HIV-1 RT is a heterodimeric enzyme, comprising of the p66 and p51 subunits. Earlier, we have shown that the β7-β8 loop of p51 is a key structural element for RT dimerization (Pandey et al., Biochemistry 40: 9505, 2001). Deletion or alanine substitution of four amino acid residues of this loop in the p51 subunit severely impaired DNA binding and catalytic activities of the enzyme. To further examine the role of this loop in HIV-1 RT, we have increased its size such that the six amino acids loop sequences are repeated in tandem and examined its impact on the dimerization process and catalytic function of the enzyme. RESULTS: The polymerase and the RNase H activities of HIV-1 RT carrying insertion in the β7-β8 loop of both the subunits (p66(INS)/p51(INS)) were severely impaired with substantial loss of DNA binding ability. These enzymatic activities were restored when the mutant p66(INS) subunit was dimerized with the wild type p51. Glycerol gradient sedimentation analysis revealed that the mutant p51(INS) subunit was unable to form stable dimer either with the wild type p66 or mutant p66(INS). Furthermore, the p66(INS)/p66(INS) mutant sedimented as a monomeric species, suggesting its inability to form stable homodimer. CONCLUSION: The data presented herein indicates that any perturbation in the β7-β8 loop of the p51 subunit of HIV-1 RT affects the dimerization process resulting in substantial loss of DNA binding ability and catalytic function of the enzyme

Drug repositioning: current scenario and future prospective for rewriting saga of drug development

Drug development is a process that demands huge investment of resources and time with only 1 drug candidate successful in reaching market among 10,000 screened taking time duration of 10-15 years and millions of dollars. This high attrition rates discourage investors and researchers. The pharmaceutical industry is shifting its attention away from de novo drug research and towards discovering novel targets and indications for already-approved drugs. In order to accelerate the drug development process with reduced risk of failure and relatively lower costs, pharmaceutical companies have adopted drug repositioning as an alternative. Therefore, a good strategy for drug development would be drug repositioning or drug repurposing, which is to identify, investigate, and exploit new therapeutic uses of already-available, on-market drugs, as well as those that have been withdrawn due to toxicities or that remain on shelves in various stages of development. The outbreak of SARS-COV-19 shows that humanity is constantly vulnerable to epidemics and new microbial attacks and that there is no time to create disease-specific therapies. Consequently, it would seem advantageous to use what is already accessible. Novel therapeutic indications that have previously been approved by the market can reduce investment costs significantly in terms of money, resources, and most importantly, time, as long as they meet PKPD and toxicity standards. Sponsors and pharmaceutical corporations get enthusiastic about additional investments and initiatives related to drug development as a consequence. The upcoming therapeutic revolution, especially with the aid of artificial intelligence, is indicated by the successful applications of several already-available drugs against COVID-19 and the various phases of repurposed drugs against TB, colorectal cancer, Alzheimer’s disease, cervical cancer, and Parkinsonism

Structural Analysis of Open Cluster Bochum 2

We present the results from our deep optical photometric observations of Bochum 2 (Boc2) star cluster obtained using the $1.3$m Devasthal Fast Optical Telescope along with archival photometric data from Pan-STARRS2/2MASS/UKIDSS surveys. We also used high-quality parallax and proper motion data from the $Gaia$ Data Release 3. We found that the Boc2 cluster has a small size ($\sim$1.1 pc) and circular morphology. Using $Gaia$ parallax of member stars and isochrone fitting method, the distance of this cluster is estimated as $3.8\pm0.4$ kpc. We have found that this cluster holds young ($\sim5$ Myr) and massive (O$7-$O$9$) stars as well as an older population of low mass stars. We found that the massive stars have formed in the inner region of the Boc2 cluster in a recent epoch of star formation. We have derived mass function slope ($\Gamma$) in the cluster region as $-2.42\pm0.13$ in the mass range $\sim0.72<$M/M$_{\odot}<2.8$. The tidal radius of the Boc2 cluster ($\sim7-9$) is much more than its observed radius ($\sim1.1$ pc). This suggests that most of the low-mass stars in this cluster are the remains of an older population of stars formed via an earlier epoch of star formation.Comment: accepted for publication in Journal of Astrophysics and Astronom

Bucky Tubes Induce Oxidative Stress Mediated Cell Death in Human Lung Cells

Unique physicochemical properties of carbon nanomaterials (CNMs) have opened a new era for therapeutics and diagnosis (known as theranostics) of various diseases. This exponential increase in application makes them important for toxicology studies. The present study was aimed at exploring the toxic potential of one of the CNMs, that is, bucky tubes (BTs), in human lung adenocarcinoma (A549) cell line. BTs were characterised by electron microscopy (TEM), dynamic light scattering (DLS), Fourier transform spectroscopy (FTIR), and X-ray diffraction (XRD). Flow cytometric study showed a concentration and time dependent increase in intracellular internalization as well as reduction in cell viability upon exposure to BTs. However, a significant increase in intracellular reactive oxygen species (ROS) production was observed as evident by increased fluorescence intensity of 2',7' - dichlorofluorescein (DCF). BTs induced oxidative stress in cells as evident by depletion in glutathione with concomitant increase in lipid peroxidationwith increasing concentrations. Asignificant increase in micronucleus formation and apoptotic cell population and loss of mitochondrial membrane potential (MMP) as compared to control were observed. Moreover, in the present study, BTs were found to be mild toxic and it is encouraging to conclude that BTs having outer diameter in the range of 7-12 nm and length 0.5-10 mu m can be used for theranostics

miR-22 regulates expression of oncogenic neuro-epithelial transforming gene 1, NET1

MicroRNAs control cellular processes by regulating expression of their target genes. Here we report that neuro-epithelial transforming gene 1 (NET1) is a target of tumor suppressor microRNA 22 (miR-22). miR-22 is downregulated in peripheral blood mononuclear cells derived from chronic myeloid leukemia (CML) patients and in CML cell line K562. NET1 was identified as one of the targets of miR-22 using both in vitro and in vivo experiments. Either mutations or naturally occurring single-nucleotide polymorphisms in NET1 3′-UTR that map at the miR-22 binding site were found to affect binding of miR-22 to NET1 mRNA. Over expression of NET1 in K562 cells resulted in increased proliferation. However decreased proliferation and alteration in cell cycle were observed on either overexpression of miR-22 or knockdown of NET1 expression respectively. We also found that overexpression of miR-22 or NET1 knockdown inhibits actin fiber formation, probably by downregulation of NET1 as NET1 knockdown also resulted in depletion of actin fiber formation. We suggest that the oncogenic properties of CML cells are probably due to deregulated expression of NET1 as a result of altered expression of miR-22