Isolation and characterization of 4-chlorophenol degrading bacterial strain from pharmaceutical xenobiotic compounds contaminated soil using enrichment technique

4- chlorophenol is available as the fundamental basic compound of numerous manufactured organics. It is produced from various sources like herbicides, wood additives, oil industries, pharmaceutical drugs and so on. It can be removed from the effluent by various ways but most effective method is bioremediation. In present study, aerobic bacterial strain was isolated from soil that was contaminated with pharmaceutical xenobiotic compounds using enrichment technique with 500 ppm of 4-chlorophenol as a sole source of carbon and energy. Colonies were isolated after 24 h of incubation on petri plate by media enrichment with 500 ppm of 4- chlorophenol and serial dilution method. 18 colonies were isolated and examined for their ability to degrade 500 ppm of 4-chlorophenol. The most potent strain, C17 was able to remove nearly ～99.93% of 4-chlorophenol in 24 h, 37 °C temperature and 6.8 pH. Based on morphological, biochemical, nucleotide homology and phylogenetic analysis the strain was found to have maximum similarity (98.98%) with Bacillus timonensis strain 10403023.     

Magnesium‐Catalyzed Hydroboration of Terminal and Internal Alkynes

A magnesium‐catalyzed hydroboration of alkynes providing good yields and selectivities for a wide range of terminal and symmetrical and unsymmetrical internal alkynes has been developed. The compatibility with many functional groups makes this magnesium catalyzed procedure attractive for late stage functionalization. Experimental mechanistic investigations and DFT calculations reveal insights into the reaction mechanism of the magnesium catalyzed protocol.     

Unveiling the binding interaction of zinc (II) complexes of homologous Schiff-base ligands on the surface of BSA protein: A combined experimental and theoretical approach

Four new zinc (II) complexes [Zn (HL¹H)Br₂] (1), [Zn (HL¹H)Cl₂] (2), [Zn₂(HL²)Br₃] (3), and [Zn (HL²)Cl] (4) have been synthesized by adopting template synthetic strategy and utilizing two homologous Schiff base ligands (H₂L¹ = 4-bromo-2-{[2-(2-hydroxyethylamino)-ethylimino]-methyl}-6-methoxyphenol, H₂L² = 4-bromo-2-{[3-(2-hydroxyethylamino)propylimino]methyl}-6-methoxyphenol), differing in one -CH₂- unit in the ligating backbone, by adopting template synthetic strategy. All the complexes have been characterized by single crystal X-ray diffraction analysis as well as by other routine physicochemical techniques. Ligand mediated structural variations have been observed and rationalized by density functional theoretical (DFT) calculations. Interaction of the complexes 1–4 with Bovine Serum Albumin protein (BSA) has been studied by different spectroscopic techniques. A complete thermodynamic profile (ΔH^o, ΔS^o and ΔG^o) was evaluated initially from the change in absorption and fluorescence spectra upon addition of BSA to the complexes. Appreciable binding constant values in the range ~ 0.94–4.51 × 10⁴ M⁻¹ indicate efficient binding tendency of the complexes to BSA with the sequence 1 ≅ 2 > 3 ≅ 4. Circular dichroism (CD), isothermal calorimetric titration experiments, molecular docking and molecular dynamics have been performed to gain deep insight into the binding regions of complex 1 to BSA. Experimental evidences suggest an interaction of zinc complexes at the surface of BSA protein and this particular binding has been exploited to determine unknown concentration of BSA protein. For this purpose complex 1 was explored as a BSA protein quantification tool.     

Lauricella hypergeometric series $$F_A^{(n)}$$ F A ( n ) over finite fields

The Ramanujan Journal - In this paper, we develop a finite field analogue for one of the Lauricella series, $$F^{(n)}_A$$ . Extending results of Greene, a finite field analogue for the multinomial...     

Development of the Vinylogous Pictet–Spengler Cyclization and Total Synthesis of (±)‐Lundurine A

A novel vinylogous Pictet–Spengler cyclization has been developed for the generation of indole‐annulated medium‐sized rings. The method enables the synthesis of tetrahydroazocinoindoles with a fully substituted carbon center, a prevalent structural motif in many biologically active alkaloids. The strategy has been applied to the total synthesis of (±)‐lundurine A.     

Synthesis and structure of 1,4-dipiperazino benzenes: chiral terphenyl-type peptide helix mimetics

The terphenyl structure has been proven to be an ideal scaffold mimicking side-chain functionalities of peptidic alpha-helices. The synthesis of 1,4-dipiperazino benzenes, using stepwise transition metal-catalyzed N-arylation of chiral piperazines to a central benzene core is reported. The structure determination by X-ray crystallography reveals a geometrical arrangement of the hydrophobic side chains resembling the orientation of key i, i + 3, and i + 7 positions in a peptidic alpha-helix or in terphenyl helix mimetics.     

Physicochemical characterization and tube-like structure formation of a novel amino acid-based zwitterionic amphiphile N-(2-hydroxydodecyl)-L-valine in water

Surface activity and aggregation behavior of an amino acid-based zwitterionic amphiphile N-(2-hydroxydodecyl)-L-valine were studied in aqueous solutions (pH 13). The self-assembly formation was investigated by use of a number of techniques including surface tension, conductivity, viscosity, fluorescence spectroscopy, dynamic light scattering, and transmission electron microscopy. The amphiphile exhibits two breaks in the surface tension vs concentration plot indicating stepwise aggregate formation and thus results in two values of critical aggregation concentration. The amphiphile was found to be very surface active compared to fatty acid soaps. The average hydrodynamic diameter and size distribution of the aggregates were obtained from DLS measurements. Conductivity measurements suggested formation of vesicles or closed tubules. TEM pictures revealed the existence of spherical vesicles, separated tubules, and tubules with multiple Y-type junctions in going from dilute to moderately concentrated solution. However, in concentrated solution, the junctions break to form separate tubular structures which upon further increase of concentration are converted to rod-like micelles. The mechanism of branched tubule formation is discussed in light of the experimental observations.     

Solvent polarity induced structural changes in 2,6-diamino-9,10-anthraquinone dye

Photophysical properties of 2,6-diamino-9,10-anthraquinone (2,6-DAAQ) dye have been investigated in different solvents and solvent mixtures. The fluorescence quantum yields, fluorescence lifetimes, radiative rate constants, nonradiative rate constants and absorption and fluorescence spectral characteristics show unusual deviations in the lower polarity aprotic solvents in comparison to those in other aprotic solvents of medium to higher polarities. The results indicate that the dye exists in different structural forms in the lower and in the medium to higher polarity solvents. Drawing an analogy with the results reported for other amino-substituted dyes, it is inferred that 2,6-DAAQ dye adopts a planar intramolecular charge transfer (ICT) structure in medium to higher polarity solvents, where the amino lone pairs are in good resonance with the anthraquinone pi-cloud. In the lower polarity solvents, however, the dye is inferred to exist in a nonplanar structure where the amino lone pairs are not in good resonance with the anthraquinone pi-cloud. Due to these structural differences, the dye displays significantly different photophysical behavior in the lower polarity solvents than in the other solvents of medium to higher polarities. Supportive evidence for the above structural changes has been obtained from ab initio quantum chemical calculations on the structures of the dye under different conditions. Unusual deviations in the photophysical properties of 2,6-DAAQ dye in protic solvents in comparison to those in aprotic solvents of similar polarities are attributed to the intermolecular hydrogen bonding effect involving the OH groups of the protic solvents and the quinonoid oxygens of the dye.     

A tetranuclear organorhenium(i) complex of the 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-p-quinodimethane radical anion, TCNQF4 (-)

The radical complex {(mu(4)-TCNQF4)[Re(CO)(3)(bpy)](4)}(PF(6))(3), as prepared and isolated from the reaction between TCNQF4 and [Re(CO)(3)(bpy)(MeOH)](PF(6)), was studied electrochemically and by IR vibrational spectroscopy, UV-Vis-NIR absorption spectroscopy, and by EPR at 9.5, 190 and 285 GHz. The isotropic g factor of 2.0058, the detectable g anisotropy, and the (185,187)Re EPR hyperfine coupling of 0.95 mT for four equivalent metal nuclei support predominant, but not exclusive, spin localisation at the bridging ligand. Nitrile and metal carbonyl stretching frequencies as well as the typically structured near infrared absorption band lend further support to (TCNQF4 (-))(Re(I))(4) as the most appropriate oxidation state formulation. In comparison to the non-radical complex {(mu(4)-TCNQ)[Re(CO)(3)(bpy)](4)}(PF(6))(4) an X-ray structure analysis of {(mu(4)-TCNQF4)[Re(CO)(3)(bpy)](4)}(PF(6))(3) shows a marginally more twisted (ReNCCCNRe)(C(6)X(4))(ReNCCCNRe) configuration and a different up/down arrangement of the [Re(CO)(3)(bpy)](+) groups. This first isolation, electrochemical, structural and spectroscopic characterisation of a discrete tetranuclear radical complex of a TCNQ-type ligand suggests a link between the stability of such materials and the rather small structural changes on ligand-based electron transfer.