Isolation and characterization of heavy metal tolerant Gram-positive bacteria with bioremedial properties from municipal waste rich soil of Kestopur canal (Kolkata), West Bengal,India

The present study was conducted to determine the culturable bacterial profile from Kestopur canal (Kolkata, India) and analyze their heavy metal tolerance. In addition to daily sewage including solid and soluble wastes, a considerable load of toxic metals are released into this water body from industries, tanneries and agriculture, household as well as health sectors. Screening out microbes from such an environment was done keeping in mind their multifunctional application especially for bioremediation. Heavy metals are major environmental pollutants when present in high concentration in soil and show potential toxic effects on growth and development in plants and animals. Some edible herbs growing in the canal vicinity, and consumed by people, were found to harbour these heavy metals at sub-toxic levels. The bioconcentration factor of these plants being <1 indicates that they probably only absorb but not accumulate heavy metals. All the thirteen Grampositive bacteria isolated from these plants rhizosphere were found to tolerate high concentration of heavy metals like Co, Ni, Pb, Cr, Fe. Phylogenetic analysis of their 16S rDNA genes revealed that they belonged to one main taxonomic group — the Firmicutes. Seven of them were found to be novel with 92–95% sequence homology with known bacterial strains. Further microbiological analyses show that the alkaliphilic Bacillus weihenstephanensis strain IA1 and Exiguobacterium aestuarii strain CE1, with selective antibiotic sensitivity along with high Ni²⁺ and Cr⁶⁺ removal capabilities, respectively, can be prospective candidates for bioremediation.     

Isolation of cinnamoyl CoA reductase and cinnamyl alcohol dehydrogenase gene promoters from <Emphasis Type="Italic">Leucaena leucocephala</Emphasis>, a leguminous tree species,and characterization of tissue-specific activity in transgenic tobacco

Promoter sequences of a 795 bp cinnamoyl CoA reductase (LlCCR) and 1,882 bp cinnamyl alcohol dehydrogenase (LlCAD) genes were isolated from Leucaena leucocephala, a leguminous tree species by genome walking, and analysed using bioinformatics tools. This revealed presence of cis-elements such as AC-boxes, XYLAT, WRKY, and MYB binding sites in addition to CAAT and TATA boxes. For functional characterization, each of LlCCR and LlCAD promoter sequences were fused to β-glucuronidase (GUS) reporter gene, immobilized into pBI101 plasmid, and introduced into tobacco via Agrobacterium tumefaciens strain LBA4404. Histochemical observations of transgenic lines indicated tissue-specific expression of GUS in the vascular tissues of leaves, stems, and roots. These results demonstrate that GUS expression driven by either LlCCR or LlCAD promoters were involved in lignifying tissues, and more specifically in differentiating xylem cells. This observed tissue-specific expression driven by either LlCCR or LlCAD promoters is sufficient for reducing the lignin content only in vascular tissues, thus overcoming the risks and challenges associated with down-regulation of lignin content in whole plants.     

Spermidine and abscisic acid-mediated phosphorylation of a cytoplasmic protein from rice root in response to salinity stress

Importance of higher polyamines, spermidine, and spermine, in relation to the mechanism and adaptation to combat abiotic stress has been well established in cereals. Owing to their polycationic nature at physiological pH, polyamines bind strongly to negative charges in cellular components such as nucleic acids, various proteins, and phospholipids. To study the physiological role of polyamine during salinity stress, phosphorylation study was carried out in cytosolic soluble protein fraction isolated from the roots of salt tolerant (Nonabokra) and salt sensitive (M-1-48) rice cultivars treated with none (control), NaCl (150 mM, 16 h), spermidine (1 mM, 16 h) or with abscisic acid (100 μM, 16 h). A calcium independent auto regulatory 42 kDa protein kinase was found to phosphorylate myelin basic protein and casein but not histone. Interestingly, this was the only protein to be phosphorylated in root cytosolic fraction during NaCl/abscisic acid/spermidine treatment indicating its importance in salinity mediated signal transduction. This is the first report of polyamine as well as abscisic acid induced protein kinase activity in rice root in response to salinity stress.     

Pd-mediated functionalization of polysubstituted pyrroles: Their evaluation as potential inhibitors of PDE4

Novel polysubstituted pyrroles have been designed and accessed via a one-pot multicomponent reaction followed by Pd-mediated C-C bond forming reactions. All the compounds synthesized were tested for their PDE4B inhibitory properties in vitro and two of them obtained via Heck reaction showed significant inhibition. The docking results suggested that these alkenyl derivatives containing ester moiety interact well with the PDE4B protein in silico where the ester carbonyl oxygen played a key role. The pyrrole framework presented here could be a new template for the identification of small molecule based novel inhibitors of PDE4. The single crystal X-ray data of a representative compound is presented.     

An ecofriendly synthesis and DNA binding interaction study of some pyrazolo [1,5-a]pyrimidines derivatives

The DNA molecule is a target for plethora of anticancer and antiviral drugs that forms covalent and non-covalent adducts with major or minor groove of DNA. In present study we synthesized series of novel Pyrazolo [1,5-a]pyrimidine derivatives. The newly synthesized compounds were characterized by elemental analysis, IR, ¹H NMR, and mass spectral data. The selected compounds were studied for interaction with Calf thymus DNA (CT-DNA) using electronic spectra, viscosity measurement and thermal denaturation studies. Further, molecular interactions were revealed for compound IIIa and IVa by computational methodologies. The preferred mode of ligand binding with double helical DNA as well as preferable DNA groove were explored by molecular docking in different DNA models.     

InCl3-catalysed synthesis of 2-aryl quinazolin-4(3H)-ones and 5-aryl pyrazolo[4,3-d]pyrimidin-7(6H)-ones and their evaluation as potential anticancer agents

A convenient and practical methodology for the synthesis of 2-aryl quinazolin-4(3H)-ones by the condensation of o-aminobenzamides with aromatic aldehydes under mild conditions using catalytic InCl(3) with good yields and high selectivities. This method has been extended for the synthesis of 5-aryl pyrazolo[4,3-d]pyrimidin-7(6H)-ones which have potential applications in medicinal chemistry. Many of these compounds were evaluated for their anti-proliferative properties in vitro against four cancer cell lines and several compounds were found to be active. Further in vitro studies indicated that inhibition of sirtuins could be the possible mechanism of action of these molecules.     

Discovery of novel antitubercular 1,5-dimethyl-2-phenyl-4-([5-(arylamino)-1,3,4-oxadiazol-2-yl]methylamino)-1,2-dihydro-3H-pyrazol-3-one analogues

In search of potential therapeutics for tuberculosis, we describe herewith the synthesis, characterization and antimycobacterial activity of 1,5-dimethyl-2-phenyl-4-([5-(arylamino)-1,3,4-oxadiazol-2-yl]methylamino)-1,2-dihydro-3H-pyrazol-3-one analogues. Among the synthesized compounds, 4-[(5-[(4-fluorophenylamino]-1,3,4-oxadiazol-2-yl)methylamino]-1,2-dihydro-1,5-dimethyl-2-phenylpyrazol-3-one (4a) was found to be the most promising compound active against Mycobacterium tuberculosis H(37)Rv and isoniazid resistant M. tuberculosis with minimum inhibitory concentrations, 0.78 and 3.12μg/mL, respectively, free from any cytotoxicity (>62.5μg/mL).     

Mycobacterium indicus pranii (Mw) re-establishes host protective immune response in Leishmania donovani infected macrophages: critical role of IL-12

Leishmania donovani, a protozoan parasite, causes a strong immunosuppression in a susceptible host and inflicts the fatal disease visceral leishmaniasis. Relatively high toxicity, low therapeutic index, and failure in reinstating host-protective anti-leishmanial immune responses have made anti-leishmanial drugs patient non-compliant and an immuno-modulatory treatment a necessity. Therefore, we have tested the anti-leishmanial efficacy of a combination of a novel immunomodulator, Mycobacterium indicus pranii (Mw), and an anti-leishmanial drug, Amphotericin B (AmpB). We observe that Mw alone or with a suboptimal dose of AmpB offers significant protection against L. donovani infection by activating the macrophages. Our experiments examining the anti-leishmanial activity of Mw alone or with AmpB also indicate a p38MAPK and ERK-1/2 regulated pro-inflammatory responses. The Mw-AmpB combination induced nitric oxide production, restored Th1 response, and significantly reduced parasite burden in wild type macrophages but not in IL-12-deficient macrophages indicating a pivotal role for IL-12 in the induction of host-protection by Mw and AmpB treatments. In addition, we observed that Mw alone or in combination with suboptimal dose of AmpB render protection against L. donovani infection in susceptible BALB/c mice. However, these treatments failed to render protection in IL-12-deficient mice in vivo which added further support that IL-12 played a central role in this chemo immunotherapeutic approach. Thus, we demonstrate a novel chemo-immunotherapeutic approach- Mw and AmpB crosstalk eliminating the parasite-induced immunosuppression and inducing collateral host-protective effects.