Antimicrobial efficacy,disease inhibition and phenolic acid-inducing potential of chloroform fraction of cow urine

High-performance liquid chromatographic (HPLC) analysis of chloroform fraction (CF) of cow urine showed rich pool of phenolic acids. Antifungal and antibacterial bioassays of CF have shown its tremendous efficacy against some fungal plant pathogens as well as human pathogenic bacteria at very low concentrations. The CF also inhibited powdery mildew (Erysiphe cichoracearum) of balsam (Impatiens balsamania) under field conditions during pre- and post-inoculation treatments. HPLC analysis of pre- and post-inoculation-treated plant leaves indicated that CF induced phenolic acid synthesis as compared to control. The results revealed that CF of cow urine has the potential for controlling some important human diseases. The result on balsam powdery mildew is a good signal that CF may also be effective against other plant diseases in the field.     

Apigenin shows synergistic anticancer activity with curcumin by binding at different sites of tubulin

Apigenin, a natural flavone, present in many plants sources, induced apoptosis and cell death in lung epithelium cancer (A549) cells with an IC₅₀ value of 93.7 ± 3.7 μM for 48 h treatment. Target identification investigations using A549 cells and also in cell-free system demonstrated that apigenin depolymerized microtubules and inhibited reassembly of cold depolymerized microtubules of A549 cells. Again apigenin inhibited polymerization of purified tubulin with an IC₅₀ value of 79.8 ± 2.4 μM. It bounds to tubulin in cell-free system and quenched the intrinsic fluorescence of tubulin in a concentration- and time-dependent manner. The interaction was temperature-dependent and kinetics of binding was biphasic in nature with binding rate constants of 11.5 × 10⁻⁷ M⁻¹ s⁻¹ and 4.0 × 10⁻⁹ M⁻¹ s⁻¹ for fast and slow phases at 37 °C, respectively. The stoichiometry of tubulin–apigenin binding was 1:1 and binding the binding constant (K_d) was 6.08 ± 0.096 μM. Interestingly, apigenin showed synergistic anti-cancer effect with another natural anti-tubulin agent curcumin. Apigenin and curcumin synergistically induced cell death and apoptosis and also blocked cell cycle progression at G₂/M phase of A549 cells. The synergistic activity of apigenin and curcumin was also apparent from their strong depolymerizing effects on interphase microtubules and inhibitory effect of reassembly of cold depolymerized microtubules when used in combinations, indicating that these ligands bind to tubulin at different sites. In silico modeling suggested apigenin bounds at the interphase of α–β-subunit of tubulin. The binding site is 19 Å in distance from the previously predicted curcumin binding site. Binding studies with purified protein also showed both apigenin and curcumin can simultaneously bind to purified tubulin. Understanding the mechanism of synergistic effect of apigenin and curcumin could be helped to develop anti-cancer combination drugs from cheap and readily available nutraceuticals.     

Mutations in exons 3 and 7 resulting in truncated expression of human ATP6V1B1 gene showing structural variations contributing to poor substrate binding-causative reason for distal renal tubular acidosis with sensorineural deafness

Distal renal tubular acidosis (dRTA) is an autosomal recessive syndrome results defect in either proximal tubule bicarbonate reabsorption or in distal tubule H⁺ secretion and is characterized by severe hyperchloraemic metabolic acidosis in childhood. dRTA is associated with functional variations in the ATP6V1B1 gene encoding β1 subunit of H⁺-ATPase, key membrane transporters for net acid excretion of α-intercalated cells of medullary collecting ducts. In the present study, a 13-year-old male patient suffering with nephropathy and sensorineural deafness was reported in the Department of Nephrology. We predicted improper functioning of ATP6V1B1 gene could be the reason for diseased condition. Therefore, exons 3, 4, and 7 contributing active site of ATP6V1B1 gene was amplified and sequenced (Accession numbers: KF571726, KM222653). The obtained sequences were BLAST searched against the wild type ATP6V1B1 gene which showed novel mutations c.307 A > G, c.308 C > A, c.310 C > G, c.704 T > C, c.705 G > T, c.709 A > G, c.710 A > G, c.714 G > A, c.716 C > A, c.717delC, c.722 C > G, c.728insG, c.741insT, c.753G > C. These mutations resulted in the expression of truncated protein terminating at Lys 209. The mutated ATP6V1B1structure superimposed with wild type showed extensive variations with RMSD 1.336 Å and could not bind to substrate ADP leading to non-functional ATPase. These results conclusively explain these mutations in ATP6V1B1 gene resulted in structural changes causing accumulation of H⁺ ions contributing to dRTA with sensorineural deafness.     

LOV‐domain photoreceptor,encoded in a genomic island,attenuates the virulence of Pseudomonas syringae in light‐exposed Arabidopsis leaves

In Arabidopsis thaliana, light signals modulate the defences against bacteria. Here we show that light perceived by the LOV domain‐regulated two‐component system (Pst–Lov) of Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) modulates virulence against A. thaliana. Bioinformatic analysis and the existence of an episomal circular intermediate indicate that the locus encoding Pst–Lov is present in an active genomic island acquired by horizontal transfer. Strains mutated at Pst–Lov showed enhanced growth on minimal medium and in leaves of A. thaliana exposed to light, but not in leaves incubated in darkness or buried in the soil. Pst–Lov repressed the expression of principal and alternative sigma factor genes and their downstream targets linked to bacterial growth, virulence and quorum sensing, in a strictly light‐dependent manner. We propose that the function of Pst–Lov is to distinguish between soil (dark) and leaf (light) environments, attenuating the damage caused to host tissues while releasing growth out of the host. Therefore, in addition to its direct actions via photosynthesis and plant sensory receptors, light may affect plants indirectly via the sensory receptors of bacterial pathogens.     

The cell aggregating propensity of probiotic actinobacterial isolates: isolation and characterization of the aggregation inducing peptide pheromone

The auto-aggregating ability of a probiotic is a prerequisite for colonization and protection of the gastrointestinal tract, whereas co-aggregation provides a close interaction with pathogenic bacteria. Peptide pheromone mediated signaling has been studied in several systems. However, it has not yet been explored in prokaryotes, especially actinobacteria. Hence, in the present study, the diffusible aggregation promoting factor was purified from the culture supernatant of a potent actinobacterial probiont and characterized using 20 different actinobacterial cultures isolated from the gut region of chicken and goat. The results showed that the pheromone-like compound induces the aggregation propensity of treated isolates. The factor was found to be a heat stable, acidic pH resistant, low molecular weight peptide which enhances the biofilm forming ability of other actinobacterial isolates. The aggregation promoting factor represents a bacterial sex factor (pheromone) and its characterization confirms its usage in the probiotic formulation     

Probing the effect of nitro groups in nitramine based energetic molecules: a DFT and charge density study

The structure, electron density distribution, energetic and electrostatic properties of simple nitramine based energetic TMA, DMNA, MDA and TNA molecules were determined using density functional theory (B3LYP) with the 6-311G^** and aug-cc-pVDZ basis sets coupled with Bader's theory of atoms in molecules. In the NO₂ group substituted molecules, the N–N bond distance increases with the increase of NO₂ groups, whereas in C–N bonds, this effect is relatively less, and the distances are almost equal. The topological analysis of electron density reveals that the electron density ρ_bcp(r) of C–N and N–N bonds are significantly decreasing with the increase of NO₂ groups in the nitramine molecules. The Laplacian of electron density ▽²ρ_bcp(r) of N–NO₂ bonds [DMNA: ? 16.7 eÅ^? 5, MDA: ? 12.8 eÅ^? 5 and TNA: ? 7.9 eÅ^? 5] of the molecules are relatively less negative, and the values also decrease with the increase of NO₂ groups; this implies that the charge concentration decreases with the increase of NO₂ groups, which leads to weakening the N–N bonds of the molecules. The isosurface of molecular electrostatic potential displays high electronegative regions around the NO₂ groups. The oxygen balance OB₁₀₀ of the molecules increases as the number of NO₂ group increases in the molecules, in which, the TNA molecule having maximum OB₁₀₀ value [+7.89]. The band gap, heat of detonation, bond dissociation energy and charge imbalance are predominantly depends on the number of NO₂ group present in the molecule. The charge imbalance parameter (ν) has been calculated for all molecules, which reveals that TNA is a highly sensitive molecule, the corresponding ν value is 0.047.     

A Protein Disulfide Isomerase Controls Neuronal Migration through Regulation of Wnt Secretion

1. Download high-res image (153KB)
2. Download full-size image

     

Unexpected Receptor Functional Mimicry Elucidates Activation of Coronavirus Fusion

1. Download high-res image (199KB)
2. Download full-size image

     

Influence of Water Hyacinth Cover on the Physico-chemical Characteristics of Water and Phytoplankton Composition in a Reservoir near Jaipur (India)

Water hyacinth (Eichhornia crassipes (Mart.) Solms.) invaded a eutrophic reservoir receiving domestic sewage near Jaipur (India) during 1975 and gradually developed a complete thick cover over the whole water body during Sept.–Oct. 1978. The physico-chemical characteristics of the water and the phytoplankton composition were studied during Sept. 1977–Sept. 1979 by fortnightly sampling. The changes observed during the second year of study are ascribed to the water hyacinth cover. The important changes were: lowering of water temperature, pH, dissolved oxygen content and nitrate nitrogen, and increase in total alkalinity, free carbon dioxide, chemical oxygen demand, ammonia nitrogen, sulphides, calcium, magnesium and phosphate phosphorus. The changes in the phytoplankton were both qualitative and quantitative. The green algae, particularly the species of Ankistrodesmus, Chlorella, Crucigenia and Selenastrum, increased considerably and replaced the blue-green algae, of which Oscillatoria and Microcystis disappeared totally. The densities of several other taxa changed significantly.