The antioxidative activity of the methanol extracts obtained from twelve commonly consumed wild edible mushrooms was investigated according to the phosphomolybdenum method, inhibition of linoleic acid peroxidation, reducing power, metal chelating, O(2)(˙-), DPPH(˙), peroxide and H(2)O(2) scavenging activity in the Black Sea Region of Turky, and compared to standard antioxidant compounds such as a-tocopherol, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and trolox. Total phenolic compounds, flavonoids, anthocyanins, ascorbic acid, β-carotene and lycopene in the extracts were measured. The antimicrobial activities of extracts were also evalated against gram (-) and (+) bacteria and yeast with disc diffusion method. Hydnum repandum, Lactarius delicious, Lactarius camphoratus, Lactarius piperatus, Ramaria flava, and Agaricus bisporus were greater than α-tocopherol and BHT on antioxidant activity. The lipid peroxidation of L. camphoratus and Lactarius volemus was excellent, and was 58.05% and 61.44% respectively. The DPPH(˙) scavenging effects decreased in the order of R. flava>BHT> Macrolepiota procera>L. camphoratus>L. piperatus>Lactarius volemus>a-tocopherol and were, at 500 µg/ml and were 80.38, 76.61, 69.74, 61.55, 61.47, 61.09, 60.65%, respectively. All the extracts of mushroom also had the stronger chelating effect according to standards. The O(2)(˙-) scavenging effect of extracts of the mushroom species was in order of R. flava>Boletus edulis>Leatiporus sulphureus>M. procera>standards. L. piperatus, L. camphorates, L. volemus, A. bisporus, Chanterellus cibarius, L. sulphureus, H. repandum showed strong antimicrobial activity, especially on E. coli. H. repandum exhibited to be more effective on P. aeruginosa than other bacterial strains.

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Aims: The aim of this study was to investigate the links between survival of Escherichia coli in sea water microcosms in the laboratory and the presence of porins in the outer membrane. The E. coli strains studied were a wild-type strain and a series of outer membrane protein (omp) mutants. Methods and Results: Bacteria were suspended in natural or filtered-autoclaved sea water microcosms and numbers determined over an incubation period by plate count and by count of cells capable of respiration. Conclusions: The type of omp mutation has a significant impact in bacterial survival. The double OmpC-OmpF mutant and the OmpR mutant (which was incapable of synthesizing OmpC and OmpF) survived poorly compared with single omp mutants and the wild-type strain. This suggests that these proteins are important in determining the entry of E. coli into the survival mode. The EnvZ mutant, which lacks the protein by which the cell senses some changes in the environment, survived as well as the wild-type strain when compared by plate counts and by respiring cell count. The loss of the EnvZ protein has no effect on survival but it could prevent the organism sensing the changes in the environment through which entry into the survival state is triggered. Significance and Impact of the Study: This work is another piece in the puzzle as to how bacteria survive stress conditions.

Background: Light and photosensitizers affectthe survival of bacteria in natural environments. Also light and photosensitizers are used for disinfection of materials such as blood, blood products, and water..Objectives: The present study was aimed toinvestigate the effect of different wavelengths of visible light and UV-A on the synthesis of some oxidative stress enzymes of Escherichia coli(E. coli) in seawater..Materials and Methods: Seawater were filtered by using Whatmann No:1 filter paper, followed by sterilization in the autoclave. The E. coli W3110 strain was grown at 37 oC, centrifuged, and transferred in seawater, then methylene blue was added to the seawater samples, with the exception of control samples. The seawater samples were incubated with white, blue, green, red, and UV-A light sources. Cell extracts were prepared by sonication, and then catalase, superoxide dismutase (SOD),glutathion peroxidase(GP),and glucose-6-phosphate dehydrogenase(G-6-PD) activities were measured..Results: It was found that in all studied wavelengths with or without Methylene Blue (MB), the level of all studied enzymes decreased remarkably when compared to dark controls. It was observed that the synthesis level of SOD, glutathione peroxidase GP, and glucose 6 phosphate dehydrogenase G-6-PD in E. coli decreased significantly in red light with respect to white, blue, and green light in seawater, to which methylene blue was added. In E. coli the decrease was 13% of G-6-PD expression, 10% of GP expression, and 17% of SOD expression in red light with MB after 16-hour incubation in seawater; however, these enzymes decreased to 45%, 84%,and 71% in white light, 33%, 47%, and 54% in blue light, 53%, 53%,and 64% in green light at the same incubation hours, respectively. Also, the enzyme acitivity in red light without MB did not show a significant difference when compared to other light sources..Conclusions: It was shown in the present study that red light among visible light sources has a crucial effect in decreasing the oxidative stress enzymes in seawater containing MB