187 research outputs found

    CHEMICAL AND BIOLOGICAL ANALYSIS OF THE BIOCTIVE FRACTIONS OF THE LEAVES OF SCAEVOLA TACCADA (GAERTN.) ROXB

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    Objective: Scaevola taccada. (Gaertn.) Roxb. is widely dispersed all along the coasts of Africa. It is used in folk medicine for diversity of ailments. This study aims to investigate the major phytoconstituents and biological activities of the leaves of S. taccada (Gaertn.) Roxb. Methods: In vitro biological examination viz. antimicrobial, cytotoxic and antioxidant activities of the ethanol extract of the leaves (EE) and its fractions; (petroleum ether (PE), methylene chloride (MC), ethyl acetate (EA) and n-butanol(BuOH)) were carried out. Estimation of the phytochemicals of biologically active fractions was done. Results: n-butanol fraction displayed remarkable antimycobacterium activity. Petroleum ether as well as n-butanol fractions evidenced a cytotoxic effect on breast carcinoma cell line (MCF7) and colon carcinoma cell line (HCT) with IC50 11.7 and 15.04 µg/ml respectively. Moreover, ethyl acetate fraction exhibits an antioxidant effect with EC50 476.7±0.57 µg/ml. n-tetradecane 1, α-amyrin palmitate 2, α-amyrin acetate 3, α-amyrin 4, stigmasterol 5, luteolin-7-O-β-glucoside 6, rutin 7 and alidyjosioside 8 were identified in S. taccada (Gaertn.) Roxb. leaves. Conclusion: Petroleum ether fraction is a cytotoxic candidate, especially against (MCF-7). It exhibited a moderate antifungal and antibacterial against certain Gram-positive bacteria. Ethyl acetate showed an antioxidant effect along with moderate antifungal activity. n-butanol fraction exerted potential antimycobacterial, significant cytotoxic activity against (HCT), good antifungal and antibacterial against Gram-positive and Gram-negative bacteria. Stigmasterol, luteolin-7-O-β-glucoside, rutin and alidyjosioside were isolated for the first time from S. taccada (Gaertn.) Roxb. Leaves

    Study of the Electrical Properties and Swelling Mechanism in Compressed Butyl Rubber Loaded with Carbon Black

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    The dependence of both electrical conductivity "σ" and dielectric constant "ε" for samples containing different carbon black concentrations were studied at different loads. It was found that, "σ" and "ε" are nearly load independent at low concentration, however, they change at higher concentration of carbon black. Swelling of the samples in both benzene and kerosene was measured, and found to be dependent on both carbon black concentration and the type of solvent used. The diffusion coefficient, penetration rate and the molecular mass were calculated

    Effect of humic acids and the amount of mineral fertilizer on some characteristics of saline soil, growth and yield of broccoli plant under salt stress conditions

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    Saabunud / Received 09.04.2022 ; Aktsepteeritud / Accepted 19.06.2022 ; Avaldatud veebis / Published online 19.06.2022 ; Vastutav autor / Corresponding author: Duraid K. A. Al-Taey ; [email protected] (A pots experiment was undertaken to determine the combined effect of humic acids and mineral fertilizer on some characteristics of saline soil, growth, and yield components of broccoli. The experiment was conducted in a randomized complete block design with three replications. The first factor consists of two levels of humic acids, namely without humic acid (H0 = 0.00 g L–1 ) and humic acid application (H1 = 0.35 g L–1 ), while the second factor included nine fertilizer (92 kg N ha –1 , 200 kg P2O5 ha–1 , 150 kg K2O ha–1 ) application rates that were (100, 100, 100%), (120, 120, 120%), (120, 120, 100%), (80, 120, 120%), (100, 100, 120%), (80.100, 100%), (120, 80, 80%), (100, 80, 80%), (80, 80, 80%) which added as a percentage of original fertilizer recommendation taking the symbols of R1 to R9 respectively. The treatment R1 was designated as a control treatment. The results indicated that humic acid application (H1) and increasing the amount of applied mineral fertilizer (R2) reduced the hydraulic conductivity of the soil for different soil depths. Humic acid addition (H1) increased concentrations of calcium and magnesium while reducing sodium concentration compared to control (H0). Contrary to humic acid, increasing the supplied mineral fertilizer led to a reduction in concentrations of calcium and magnesium while increasing sodium concentration in the soil. The sodium adsorption in soil particles in the ground was decreased due to humic acid application while improving the mineral fertilizer. Humic acid (H1) combined with increasing the amount of chemical fertilizer (R2) gave the desirable results in decreasing the sulphate, chloride and bicarbonate in the soil profile. The addition of humic acid (H1) and increasing mineral fertilizer application (R2) led to a significant increase in plant height, leaf area and head weight of broccoli per plant. Similarly, the interaction between humic acids and chemical fertilizers (H1R2) led to a significant increase in plant height, leaf area and head weight of broccoli per plant

    Genome-wide association mapping in a diverse spring barley collection reveals the presence of QTL hotspots and candidate genes for root and shoot architecture traits at seedling stage

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    Figure S1. Examples of scanned root images from individual plants. Figure S2. Concatenated split network tree for the collection of 233 accessions based on 6019 SNP markers. Figure S3. LD pattern along the individual chromosomes of barley. Figure S4. Schematic representation of the eight re-sequenced candidate genes models. (DOCX 3427 kb

    Development of Non-Natural Flavanones as Antimicrobial Agents

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    With growing concerns over multidrug resistance microorganisms, particularly strains of bacteria and fungi, evolving to become resistant to the antimicrobial agents used against them, the identification of new molecular targets becomes paramount for novel treatment options. Recently, the use of new treatments containing multiple active ingredients has been shown to increase the effectiveness of existing molecules for some infections, often with these added compounds enabling the transport of a toxic molecule into the infecting species. Flavonoids are among the most abundant plant secondary metabolites and have been shown to have natural abilities as microbial deterrents and anti-infection agents in plants. Combining these ideas we first sought to investigate the potency of natural flavonoids in the presence of efflux pump inhibitors to limit Escherichia coli growth. Then we used the natural flavonoid scaffold to synthesize non-natural flavanone molecules and further evaluate their antimicrobial efficacy on Escherichia coli, Bacillus subtilis and the fungal pathogens Cryptococcus neoformans and Aspergillus fumigatus. Of those screened, we identified the synthetic molecule 4-chloro-flavanone as the most potent antimicrobial compound with a MIC value of 70 µg/mL in E. coli when combined with the inhibitor Phe-Arg-ß-naphthylamide, and MICs of 30 µg/mL in S. cerevesiae and 30 µg/mL in C. neoformans when used alone. Through this study we have demonstrated that combinatorial synthesis of non-natural flavonones can identify novel antimicrobial agents with activity against bacteria and fungi but with minimal toxicity to human cells

    Local-Scale Patterns of Genetic Variability, Outcrossing, and Spatial Structure in Natural Stands of Arabidopsis thaliana

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    As Arabidopsis thaliana is increasingly employed in evolutionary and ecological studies, it is essential to understand patterns of natural genetic variation and the forces that shape them. Previous work focusing mostly on global and regional scales has demonstrated the importance of historical events such as long-distance migration and colonization. Far less is known about the role of contemporary factors or environmental heterogeneity in generating diversity patterns at local scales. We sampled 1,005 individuals from 77 closely spaced stands in diverse settings around Tübingen, Germany. A set of 436 SNP markers was used to characterize genome-wide patterns of relatedness and recombination. Neighboring genotypes often shared mosaic blocks of alternating marker identity and divergence. We detected recent outcrossing as well as stretches of residual heterozygosity in largely homozygous recombinants. As has been observed for several other selfing species, there was considerable heterogeneity among sites in diversity and outcrossing, with rural stands exhibiting greater diversity and heterozygosity than urban stands. Fine-scale spatial structure was evident as well. Within stands, spatial structure correlated negatively with observed heterozygosity, suggesting that the high homozygosity of natural A. thaliana may be partially attributable to nearest-neighbor mating of related individuals. The large number of markers and extensive local sampling employed here afforded unusual power to characterize local genetic patterns. Contemporary processes such as ongoing outcrossing play an important role in determining distribution of genetic diversity at this scale. Local “outcrossing hotspots” appear to reshuffle genetic information at surprising rates, while other stands contribute comparatively little. Our findings have important implications for sampling and interpreting diversity among A. thaliana accessions

    Thirty Years with EoS/G<sup>E</sup> Models - What Have We Learned?

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