of marine red seaweeds (Jania rubens, Corallina mediterranea and Pterocladia capillacea), J. Taibah Univ. Sci. (2015), http://dx. AbstractSeaweeds are potential renewable resources in the marine environment. The antibacterial activity of Jania rubens, Corallina mediterranea and Pterocladia capillacea were analyzed against human pathogenic bacteria. The present study was performed to investigate the phytochemical constituents of seaweeds, such as alkaloids, flavonoids, steroids, terpenoids and phlobatannins. In this study, we estimated phenols, flavonoids, tannins, pigments and mineral contents and determined the hydrogen peroxide scavenging activity, reducing power and total antioxidant activity of various extracts of selected seaweeds. Phytochemicals were extracted from the three seaweeds using various solvents, such as methanol, ethanol, acetone and chloroform. Among the various extracts, the methanolic extract was found to have the highest reducing power and total antioxidant capacity. We evaluated the seaweeds against Vibrio fluvialis, and Pterocladia capillacea was the most effective at controlling its growth. The highest zone of inhibition was recorded in the methanol extract. The chemical constituents of the seaweeds were characterized by GC-MS, which showed that they contain organic compounds, such as 1,2-benzenedicarboxylic acid.

Coral reefs are the most biodiverse and biologically productive of all marine ecosystems. Corals harbor diverse and abundant prokaryotic groups. However, little is known about the diversity of coral-associated microorganisms. We used molecular techniques to identify and compare the culturable bacterial assemblages associated with the soft coral Sarcophyton glaucum from the Red sea. Different media were utilized for microbial isolation, and the phylogeny of the culturable bacteria associated with the coral was analyzed based on 16S rDNA sequencing. The coral associated bacteria were found to be representatives within the Gammaproteobacteria, Actinobacteria, and Firmicutes. Antimicrobial activities of twenty bacterial isolates were tested against four pathogenic bacteria (Staphylococcus aureus, Klebsiella pneumonia, Pseudomonas aeruginosa, Vibrio fluvialis) and three fungi (Penicillium sp., Aspergillus niger, Candida albicans). A relatively high proportion of bacterial strains displayed distinct antibacterial and antifungal activities, suggesting that soft coral-associated microorganisms may aid their host in protection against marine pathogens. Members of genera Bacillus and Pseudomonas had the highest proportion of antimicrobial activity which supported the hypothesis that they might play a protective role in the coral hosts.

In this study we investigated the phytoconstituents Calluna vulgaris, Ferula hermonis and Tribulus terrestris, and then assessed their possible biological activities by using standard methods. A preliminary phytochemical investigation of the three extracts revealed the presence of alkaloids, flavonoids, proteins, lipids, phenolic compounds, saponins, sterols and amino acids. Three extracts showed anti-oxidant effect as they inhibited the 1,1-diphenyl-2-picryl hydrazyl (DPPH) oxidation and production of thiobarbituric acid reactive substances (TBARS). Moreover, three extracts showed anti-acetylcholiesterase (AChE) and this effect was concentration dependent. C. vulgaris was the most potent inhibitor of AChE. Furthermore, the three plant extracts had an inhibitory effect toward α-glucosidase. The inhibitory effect was concentration dependent and the most potent inhibitor for α-glucosidase was the extract from T. terrestris. Calluna vulgaris showed anti-inflammatory effect at tested concentrations while the other two extracts exhibited this effect only at concentration of 25 μg/mL. Finally, C. vulgaris had a significant effect against pathogenic bacteria (Agrobacterium tumefaciens, Erwinia sp., Klebsiella pneumonia and Pseudomonas aeruginosa) in comparison to other extracts from Ferula sp., or Tribulus sp. In conclusion, all tested extracts could be promising sources for the treatment of diabetes, Alzheimer's disease, infectious diseases and oxidative stress related disorders because they are rich in phenols and flavonoids that give anti-oxidant molecules and produce an inhibitory effect against the tested enzymes.

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Three different azo dyes such as Fast red, metanil yellow and Fast orange were examined for their decolorization by O. oeni ML34. Fast red (FR) was decolorized by 68%, whereas the other dyes were removed by only about 30%. The effects of glucose addition, substrate (dye) concentration and environmental factors (temperature, pH) on decolorization were investigated by two-level factorial design. The statistical analyses revealed that glucose specifically increases the extent of FR decolorization. A glucose level of 5 g/l was the optimum concentration for removal of, FR reaching a decolorization percentage of up to 93%.

Six isolates with phenol degrading ability were obtained from marine sediments by enrichment procedures and an isolate, AM4, was identified as Alcaligenes sp. by 16S rDNA sequencing. The Plackett-Burman design was applied to estimate the significance of culture medium components and conditions for phenol degradation by Alcaligenes sp. AM4. The resulting medium formula which was predicted to be near optimal was: phenol conc. (240 μg/ml), culture volume (37.5 ml), inoculum's size (0.15 ml), NH4SO4 (0.5 g/l), K2HPO4 (0.75 g/l), KH2PO4 (0.75 g/l), MgSO4 (0.3 g/l) and NaCl (0.25 g/l). Scanning electron microscopy was applied to cells exposed to phenol, and a larger cell size was detected, resulting in a reduced cell surface. This relative reduction of the cell surface represents a cellular mechanism to reduce the toxic effect of this environmental stress factor.

Four local Bacillus thuringiensis (Bt) isolates that had been serologically identified as Bt var. kurstaki (Btk2, Btk3, and Btk66) and Bt var. mexicanensis (Btm27), in addition to two reference strains (4D20 and 4AC1), were laboratory assayed as microbial control agents against the Egyptian cotton leafworm Spodoptera littoralis (Boisd.). Polymerase chain reaction (PCR) amplification analysis revealed that each of the six experimental strains carries, at least, a cry1 type gene which expresses a protein toxin active against lepidopterous insects. Additionally, PCR amplification results demonstrated that 4D20 and Btk66 contain the Lepidoptera- and Diptera-active cry2 type gene and that Btk66 contains Coleoptera-active cry7 and cry8 genes. Among the six strains, Btk66 and Btm27 were the most promising microbial control agents against S. littoralis. The present findings were the first to report that Btm27 (classified as B. thuringiensis var. mexicanensis) is a very potent microbial control agent against S. littoralis-tested larvae. For more characterization of these two isolates, the sspO gene was investigated as a molecular chronometer. The DNA sequencing results proved that Btk66 and Btm27 carry sspO open reading frames with identical nucleotide sequences, suggesting a strong phylogenetic relationship between the two strains.

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