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Potato (Solanum tuberosum L.) is widely used for many industrial and food applications. Nine potato cultivars were planted and collected from a private farm in new Salihiyyah city, Sharkia governorate, Egypt to compare between them at morphological, molecular, biochemical and anatomical levels. Our results indicated that the Inova cultivar was better, however the Bafana cultivar was worse in relation to yield parameters. Inter simple sequence repeat (ISSR) molecular marker has been used to determine the genetic diversity between these nine cultivars. Through using ten primers we obtained 98 bands, 85 of which were polymorphic by 87%. The highest similarity value (0.827) was found between Caruso and Alliance as the closest but the lowest value (0.418) was found between Charlotte and Bafana as the most distant. Everest tuber contained great amounts of total phenolic and peroxidase activity, while the Bafana tuber contained small amounts of it compared to other cultivars. The phellem layer of the Everest tuber had more thickness than others and the number of phellem rows was the highest. However, the Bafana cultivar listed the lowest value compared to other cultivars. Lower values from both of total bacterial and total fungi were recorded on the tuber of the Everest cultivar. However, Bafana cultivar was recorded to have a higher value of both compared to other cultivars. We suggest that the ISSR marker is a suitable procedure to examine the potato's genetic diversity at the DNA level. The Everest cultivar is considering the best cultivar to planting and breeding in Egypt.ª 2014 Production and hosting by Elsevier B.V. on behalf

ontamination of aquatic ecosystems with heavy metals has increased worldwide. Heavy metals are interesting and noteworthy due to their strong impact on aquatic ecosystems and their bioaccumulation in hydrobionts. Cadmium and Copper were tested in genotoxicity assays with some contradictory results (Ayllon and Garcia, 2000; Conners and Black, 2004). Metal accumulation causes an increase in highly reactive oxygen species (ROS) such as hydrogen peroxide, superoxide radical, hydroxyl radical which leading to oxidative stress in fish (Dautremepuits et al., 2002). Many factors including heavy metals in soil and waste water (Yu, 2000) can affect the DNA genetic material of organisms directly or indirectly and not only to damage the integrity of the DNA structure but also influence its expression and eventually cause genotoxicity to organisms. Copper sulfate is one of the pesticides that can be troublesome. The most copper sources are the agricultural fertilizers and pesticides and the frequent cause of poisoning in aquatic ecosystems. Copper compounds are also found in preservatives, additives and coloring

The well-known probiotic GRAS Saccharomyces boulardii (CNCM I-745) was used for the rst time to produce glutathione (GSH). The culture conditions affecting GSH biosynthesis were screened using a Plackett-Burman design (PBD). Analyzing the regression coe cients for 12 tested variables; 6 of them, including yeast extract, glucose, peptone and cysteine; temperature and agitation rate had a positive signi cant effect on GSH production with a maximum production of 192 mg/L. The impact of addition time of cysteine was investigated in 19 experiments during the growth time course (0-36 h), the best addition time was 8h post-inoculation producing 235 mg/L of GSH. The most signi cant variables were further explored at 5-levels using Central Composite Rotatable Design (CCRD), giving a maximum production of GSH (552 mg/L). Using ba ed asks, the GSH was increased to 730 mg/L, i.e 1.32-folds increment than obtained using CCRD. The two rate-limiting genes of GSH biosynthesis "γ-glutamyl cysteine synthetase (gsh1) and GSH-synthetase (gsh2) were ampli ed and sequenced to validate the GSH biosynthetic potency of S. boulardii. The sequences of genes showed 99% similarity with gsh1 and gsh2 genes of S. cerevisiae. Glutathione peroxidase was puri ed and characterized from S. boulardii with molecular mass and subunit structure of 80 kDa and 35 kDa as revealed from native and SDS-PAGE, ensuring its homodimeric identity. The activity of GPx was reduced by 2.5-folds upon demetallization con rming its metalloproteinic identity. The enzyme was strongly inhibited by hydroxylamine and DTNB, ensuring the implication of surface lysine and cysteine residues on the enzyme active site domains.