<Emphasis Type="Italic">Streptomyces</Emphasis> sp. strain SK68, isolated from peanut rhizosphere,promotes growth and alleviates salt stress in tomato (<Emphasis Type="Italic">Solanum lycopersicum</Emphasis> cv. Micro-Tom)

A novel actinobacterium, strain SK68, was isolated from the rhizosphere of peanut plant and its salinity stress alleviation ability was studied using tomato (Solanum lycopersicum cv. Micro-Tom) plants. Based on 16S rDNA based phylogenetic analysis, strain SK68 has been identified as a Streptomyces sp. Strain SK68 had branched substrate mycelium bearing smooth surfaced spores and the spore colour is brownish grey on ISP4 medium. It exhibited enzyme activities such as xylanase, cellulase, amylase, and pectinase and degraded hypoxanthine, casein, and L-tyrosine. The strain SK68 differed in its banding pattern in BOX-PCR and RAPD fingerprinting compared to the closely matching type strains Streptomyces erythrochromogenes NBRC 3304^T (AB184746), S. flavotricini NBRC 12770^T (AB184132), S. racemochromogenes NBRC 12906^T (AB184235), and S. polychromogenes NBRC 13072^T (NR041109). Strain SK68 was evaluated for its salinity stress-alleviating activity in tomato plants with 180 mmol/L NaCl under gnotobiotic condition. A significant increase in plant biomass was observed in strain SK68-inoculated tomato plants under salt stress compared to control and salt-stressed non-inoculated plants.     

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.     

Copper oxide nanoparticles induce anticancer activity in A549 lung cancer cells by inhibition of histone deacetylase

Objectives

Copper oxide nanoparticles (CuO NPs) promoting anticancer activity may be due to the regulation of various classes of histone deacetylases (HDACs).

Results

Green-synthesized CuO NPs significantly arrested total HDAC level and also suppressed class I, II and IV HDACs mRNA expression in A549 cells. A549 cells treated with CuO NPs downregulated oncogenes and upregulated tumor suppressor protein expression. CuO NPs positively regulated both mitochondrial and death receptor-mediated apoptosis caspase cascade pathway in A549 cells.

Conclusion

Green-synthesized CuO NPs inhibited HDAC and therefore shown apoptosis mediated anticancer activity in A549 lung cancer cell line.

     

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.     

Larvicidal and smoke repellency effect of Toddalia asiatica and Aegle marmelos against the dengue vector, Aedes aegypti (Insecta: Diptera: Culicidae)

Investigations were made to evaluate the larvicidal activity and smoke repellent potential of Toddalia asiatica (L.) and Aegle marmelos at different concentrations (20, 40, 60, 80 and 100 p.p.m.) against first to fourth instar larvae and pupae of Aedes aegypti (L.). The LC₅₀ of A. marmelos and T. asiatica against first instars was 50.960 and 47.893 p.p.m., respectively; against second instars, 52.979 and 50.922; third instars, 56.653 and 54.461; and fourth instars, 60.778 and 61.278. The LC₅₀ and LC₉₀ for A. marmelos and T. asiatica against pupae were 56.634 and 112.992, and 53.64 and 116.22 p.p.m., respectively. The smoke toxicity of T. asiatica against Ae. aegypti was greater than that of A. marmelos . Smoke-exposed gravid females oviposited fewer eggs when compared to those that were not exposed to smoke. Smoke-exposed females hatched a lower percentage of eggs compared to unexposed females.     

Feeding habit and food partitioning in a stream fish community of Western Ghats,India

The diet and feeding ecology of 12 cyprinid fishes were studied in the Thalayanai stream of southern India. The diet of Barbodes sarana, Danio aequipinnatus and Rasbora daniconius were specialized in terrestrial and aquatic insects. Hypselobarbus dobsoni and Garra mullya consumed vegetative matter and unicellular algae as their most important dietary component, respectively. Hypselobarbus curmuca and Hypselobarbus dubius specialized in crustaceans and molluscs. Puntius amphibious, Puntius bimaculatus, Puntius dorsalis, Puntius filamentosus and Puntius tambraparniei fed on variety of food resources (aquatic insects, algae and detritus) and their feeding intake varied between wet to dry seasons. Levin’s index of diet breadth showed the broadest diets for P. dorsalis in both seasons, whereas G. mullya had a narrow feeding spectrum in both seasons. Among co-existing species, diet overlaps were substantially low during both wet and dry season. These results suggest that feeding specialization and low diet overlap reduce inter-specific competition, allowing co-existence of these cyprinid fishes in this highly structured stream assemblage.     

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.     

Interactions of feeding rates on growth,food conversion and body composition of the freshwater catfish Mystus vittatus (Bloch)

Food intake, growth, conversion efficiency and body composition of the non-air breathing catfish Mystus vittatus (Bloch) were studied in relation to different feeding levels. Fish weighing 817.9 ± 104.00 mg was found to consume a maximum of 156.0 mg live Tubifex worm/g day^-1. Geometrically derived feeding rates of 6.75, 23.00 and 26.00 mg dry food/g live fish day^-1 represent the maintenance, optimum and maximum levels respectively. The SDA increased from 6.75 mg/g day^-1 at maintenance to 13.50 mg/g day^-1 at maximum feeding rate. Starvation brougt about increase in body water content, while there was concomitant decrease in fat and crude protein.