In vitro and in vivo efficacy of rosmarinic acid on quorum sensing mediated biofilm formation and virulence factor production in Aeromonas hydrophila

Rosmarinic acid (RA) was assessed for its quorum sensing inhibitory (QSI) potential against Aeromonas hydrophila strains AH 1, AH 12 and MTCC 1739. The pathogenic strains of A. hydrophila were isolated from infected zebrafish and identified through biochemical analysis and amplification of a species-specific gene (rpsL). The biofilm inhibitory concentration (BIC) of RA against A. hydrophila strains was found to be 750 μg ml^?1. At this concentration, RA reduced the QS mediated hemolysin, lipase and elastase production in A. hydrophila. In FT-IR analysis, RA treated A. hydrophila cells showed a reduction in cellular components. Gene expression analysis confirmed the down-regulation of virulence genes such as ahh1, aerA, lip and ahyB. A. hydrophila infected zebrafish upon treatment with RA showed increased survival rates. Thus, the present study demonstrates the use of RA as a plausible phytotherapeutic compound to control QS mediated biofilm formation and virulence factor production in A. hydrophila.     

Biological and protein‐binding studies of newly synthesized polymer–cobalt(III) complexes

The polymer–cobalt(III) complexes, [Co(bpy)(dien)BPEI]Cl₃ · 4H₂O (bpy = 2,2′‐bipyridine, dien = diethylentriamine, BPEI = branched polyethyleneimine) were synthesized and characterized. The interaction of these complexes with human serum albumin (HSA) and bovine serum albumin (BSA) was investigated under physiological conditions using various physico‐chemical techniques. The results reveal that the fluorescence quenching of serum albumins by polymer–cobalt(III) complexes took place through static quenching. The binding of these complexes changed the molecular conformation of the protein considerably. The polymer–cobalt(III) complex with x = 0.365 shows antimicrobial activity against several human pathogens. This complex also induces cytotoxicity against MCF‐7 through apoptotic induction. However, further studies are needed to decipher the molecular mode of action of polymer–cobalt(III) complex and for its possible utilization in anticancer therapy. Copyright © 2015 John Wiley & Sons, Ltd.     

Factor analysis in relation to breeding system

The forces of divergence in the cultivated populations of crops belonging to different breeding systems,Sorghum, Pennisetum, Brassica, linseed and wheat, have been examined utilising the centroid method of factor analysis. The populations consisted of mostly elite material of high productivity.Three factors were found to be adequate to account for most of the total communality although upto fourteen variables have been included. The results confirmed that the use of genetic correlation matrices in populations under intensive human selection would change the factor loadings to a considerable degree as compared to environmental correlation matrices.The factor loadings inSorghum indicated the important role of the reproductive factor and the growth factor in the evolution of this genus. In the case ofPennisetum, ear girth, ear length and height were important in the first factor, while early vigour and flowering time were predominant for the second foctor. InBrassica, the data have also indicated that disruptive selection for flowering time had substantially modified factor loadings in ease of the genotypic correlation matrix and had, therefore, substantially modified the course of evolution. In the case of linseed, the inclusion of F₁ hybrids did not change the major conclusions drawn about factor loadings for factors from the genotypic correlation matrix.The number of factors and the loadings did not appear to be directly related to the breeding system but were found to be influenced by the past history of selection. The first factor which contributed the most to the total communality was concerned with reproductive capacity and characters influencing major components of fitness under both human and natural selection.Presented at the 21st annual general conference of the Indian Society of Agricultural Statistics held at Lucknow in February, 1968.     

Enhanced cross pollination to widen the scope of breeding in groundnut (Arachis hypogaea L.)

Summary Six groundnut genotypes belonging to the Virginia and Valencia sub-groups were irradiated with gamma rays at doses of 5, 10, 15 and 20 kR, much below LD₅₀, and grown surrounded by a pollen parent in a split-plot design. The succeeding two generations were checked for the occurrence of hybrids by examining the segregation for pod and seed characteristics and the two quantitative characters, pod and seed yield. Cross-pollination up to 20.8% was observed in M13, a Virginia cultivar. There was a genotype-dose interaction for the extent of cross-pollination. Cross-pollination was higher in Virginia than Valencia genotypes and more frequent under 15 and 20 kR than under other doses, in general. The observed substantial enhancement of cross-pollination encourages the use of seed irradiation at proper doses as a method for increasing recombination in plant breeding programmes.     

Harpacticoid copepods associated with the seagrass Halophila ovalis in the Ashtamudi Estuary,south-west coast of India

A temporal study of harpacticoid copepod populations associated with the seagrass Halophila ovalis was undertaken in the Ashtamudi Estuary, south-west coast of India. A total of 19 species representing 8 families was recorded in this assemblage. Harpacticoids formed 7.52% of the total phytal meiofauna. At the species level, harpacticoids exhibit parallel assemblages with phytal zones, found in other localities.     

Mycelium of fungi isolated from mouldy foods inhibits Staphylococcus aureus including MRSA – A rationale for the re-introduction of mycotherapy?

Fungal mycelium capable of producing antibacterial agents was isolated from samples of apple, beetroot, lemon and orange; the mycelium of all isolates produced penicillin, while the apple and beetroot samples also produced the antibacterial mycotoxin patulin. The known penicillin-producing fungi were shown to produce penicillin, but not patulin. The mycelial discs of all of fruit and vegetable isolates, as well as the two known penicillin producing fungi, inhibited Staphylococcus aureus, and mycelium of all isolates inhibited MRSA, in contrast, only one of the two known penicillin-producers did so. The results are discussed in relation to the possibility of using the mycelium of Penicillium species in mycotherapy.     

Sodium alginate from Sargassum wightii retards mortalities in Penaeus monodon postlarvae challenged with white spot syndrome virus

Sodium alginate extracted from brown seaweed Sargassum wightii (16.35 ± 1.42%, mean [±SD] yield from 5 extractions) was prepared as a powder or beads and used to enrich Artemia nauplii at concentrations of 100, 200, 300 and 400 mg l-1. The alginate-enriched nauplii were fed to Penaeus monodon shrimp postlarvae (PL) stage 15 (PL15, i.e. 15 d old) for 20 d. Mean weight gain and specific growth rate over this period were 0.24 g and 15.8%, respectively, in PL groups not fed alginate, and 0.20-0.28 g and 14.7-16.5%, respectively, in PL groups fed alginate. Amongst PL35 then challenged with white spot syndrome virus (WSSV) by immersion, all PL not fed alginate died within 9 d. However, amongst PL fed the 4 concentrations of alginate powder or beads, mortality rates reduced with increasing alginate concentration, and between 25 and 32% PL remained alive when the bioassay was terminated on Day 21. Amongst alginate-fed PL groups compared with the control group, mortality was reduced by 26.5 to 58.4%. Nested PCR detection of WSSV revealed sodium alginate concentration-dependent reductions in infection loads. The data indicate that sodium alginate extracted from brown seaweed and fed to P. monodon can retard progression of WSSV disease.     

c-myb stimulates cell growth by regulation of insulin-like growth factor (IGF) and IGF-binding protein-3 in K562 leukemia cells

c-myb plays an important role in the regulation of cell growth and differentiation, and is highly expressed in immature hematopoietic cells. The human chronic myelogenous leukemia cell K562, highly expresses IGF-I, IGF-II, IGF-IR, and IGF-induced cellular proliferation is mediated by IGF-IR. To characterize the impact of c-myb on the IGF-IGFBP-3 axis in leukemia cells, we overexpressed c-myb using an adenovirus gene transfer system in K562 cells. The overexpression of c-myb induced cell proliferation, compared to control, and c-myb induced cell growth was inhibited by anti-IGF-IR antibodies. c-myb overexpression resulted in a significant increase in the expression of IGF-I, IGF-II, and IGF-IR, and a decrease in IGFBP-3 expression. By contrast, disruption of c-myb function by DN-myb overexpression resulted in significant reduction of IGF-I, IGF-II, IGF-IR, and elevation of IGFBP-3 expression. In addition, exogenous IGFBP-3 inhibited the proliferation of K562 cells, and c-myb induced cell growth was blocked by IGFBP-3 overexpression in a dose-dependent manner. The growth-promoting effects of c-myb were mediated through two major intracellular signaling pathways, Akt and Erk. Activation of Akt and Erk by c-myb was completely blocked by IGF-IR and IGFBP-3 antibodies. These findings suggest that c-myb stimulates cell growth, in part, by regulating expression of the components of IGF-IGFBP axis in K562 cells. In addition, disruption of c-myb function by DN-myb may provide a useful strategy for treatment of leukemia.     

SIRT1 regulates oxidant- and cigarette smoke-induced eNOS acetylation in endothelial cells: Role of resveratrol

Endothelial nitric oxide synthase (eNOS) plays a crucial role in endothelial cell functions. SIRT1, a NAD⁺-dependent deacetylase, is shown to regulate endothelial function and hence any alteration in endothelial SIRT1 will affect normal vascular physiology. Cigarette smoke (CS)-mediated oxidative stress is implicated in endothelial dysfunction. However, the role of SIRT1 in regulation of eNOS by CS and oxidants are not known. We hypothesized that CS-mediated oxidative stress downregulates SIRT1 leading to acetylation of eNOS which results in reduced nitric oxide (NO)-mediated signaling and endothelial dysfunction. Human umbilical vein endothelial cells (HUVECs) exposed to cigarette smoke extract (CSE) and H₂O₂ showed decreased SIRT1 levels, activity, but increased phosphorylation concomitant with increased eNOS acetylation. Pre-treatment of endothelial cells with resveratrol significantly attenuated the CSE- and oxidant-mediated SIRT1 levels and eNOS acetylation. These findings suggest that CS- and oxidant-mediated reduction of SIRT1 is associated with acetylation of eNOS which have implications in endothelial dysfunction.