(Chlorella vulgaris) and marine algae (Chlorella salina) to different salinity levels. These algae were isolated and cultivated in appropriate media for a period of 8 days., C. vulgaris could survive till 0.8 molar NaCl, while the marine strain (C. salina) survived up to 2 molar NaCl. Thus, the marine alga showed a wide range of salinity tolerance, whereas the fresh water alga showed a narrows range of salinity tolerance. The dry weight of C. salina was 2-folds at 1M NaCl and slightly changed at 2 M NaCl as compared to the control value. In C. vulgaris dry weight was progressively decreased with increase of salinity. Hypo and hyper saline media induced significant stimulation in photosynthesis pigments, carbohydrate, protein, Na+ and K+ contents in C. salina. On the other hand, free amino acids, proline, MDA contents and antioxidant enzyme activities (SOD, CAT, POD and APX) were generally decreased. In contrary, salt stress exerted inhibitory effects on photosynthetic pigments, carbohydrate, protein and K+ contents of the fresh water alga. Free amino acids, proline, Na+, MDA contents and antioxidant enzyme activities were markedly increased in C. vulgariswith increase of salinity stress. The great salinity tolerance of C. salina, compared to C. vulgaris may be due to the effect of habitat on the behavior of the algae as being controlled with specific habitat gene (s).]]>
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p. 17−29
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STAPHYLOCOCCUS aureus (S. aureus) carrying Panton-Valentine leukocidin (PVL) has become a serious global problem. PantonValentine leukocidin-positive Staphylococcus aureus can result in several infections. Although it is associated with community acquired methicillin resistant S. aureus (MRSA), several outbreaks due to methicillin-sensitive Staphylococcus aureus (MSSA) were reported. This study was conducted to determine the frequency of PVL-positive gene in methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA) among isolates from Egyptian hospitals.
Various clinical samples were collected from two Egyptian hospitals, one in Cairo and the other in Zagazig Governorates. The samples were collected from January 2010 to December 2010 and subjected to culture then bacterial identification. S. aureus was identified by conventional methods then MRSA and MSSA isolates were identified using sensitivity test for both oxacillin and cefoxitin and the results were compared with Chrom ID MRSA (Chromogenic media for detection of MRSA). Polymerase chain reaction (PCR) was used to detect the PVL gene among 42 MRSA and 25 MSSA isolates. Among PCR tested isolates, 11.9% of S. aureus isolates harbored the PVL gene (8/67). Five MRSA isolates were harboring the gene representing also 11.9% (5/42). Three among 25 MSSA isolates were PVL positive (12%). Accordingly, no significant difference was observed between MRSA and MSSA regarding the presence of the PVL gene. On the other hand, no PVL gene was detected among 10 Gram positive isolates other than S. aureus (3 of them were coagulase negative Staphylococci).]]>
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p. 45−60
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p. 61−78
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p. 79−103
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Cyperus alopecuroides and Phragmites australis) and a third canal bank species; Phragmites australis. Sediments, soil, and water, were analyzed for Mn, Cu, Zn, Cd, Pb and Fe. Results elucidated that concentrations of Mn, Cu and Pb were higher in soils than in sediments. Roots were the most efficient hyperaccumulating organs, giving higher bioconcentration factor (BCF) values. The contents of heavy metals in the studied species followed the order: Fe > Mn > Zn > Cu > Pb > Cd. The investigation elucidated that the living roots of the studied species are hyperaccumulators for Fe, moderate accumulators for Mn, and Zn, poor accumulators for Cu and Pb and scarce accumulators for Cd. The content of all metal ions in the different organs of the studied species obeyed the order: living roots > dead roots > dead leaves > living leaves > culms and rhizomes. High Translocation Factor (TF) values of the test species confirm the capability of their roots to accumulate heavy metals and their translocation to the shoots. Therefore, rhizofiltration was found to be the best mechanism to explain that Phragmites australis and Cyperus alopecuroides are promising species for phytoremediation of wastewater and soil.]]>
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Aspergillus flavusfrom Saint Catherine protectorate achieved highest laccase production on both solid and liquid media. Identification of this fungal species was further confirmed at the molecular level based on nuclear ribosomal DNA internal transcribed spacer (ITS) identities and was found to be A. flavus strain NG85. The fungus produced statistically highest amounts of laccase after 10 days of growth at 36.7oC and when growth medium was adjusted at pH 5. D-glucose at a concentration of 24 g/l was the best carbon source. The leading nitrogen source was peptone used at 2.51 g/l. Supplementation of copper sulfate at concentration 10 μM to the optimized growth medium caused an increase of 122% in enzyme yield. The crude laccase preparation of A. flavusNG85 from Saint Catherine protectorate showed antiproliferative activity against colon carcinoma cells (HCT-116) and breast carcinoma cells (MCF-7) with IC50 values of 24.3 and 41.3 μg/ml, respectively, and a less inhibitory effect against hepatocellular carcinoma cells (HepG-2).]]>
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p. 149−159
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Acacia species are vulnerable to elimination in Saudi Arabia. In this study, seed morphology and patterns of their coat surface sculpture as revealed by scanning electron microscopy besides both seed proteins and seven isozymes profiles were employed for the discrimination and authentication the vulnerable Saudi Arabian Acacia collected from the western region of the kingdom. The scanning electron microscopic study displayed diversity in shape, dimensions, color, central aerole features and coat topography of seeds among different species to be characteristic for each species. Seed protein and isozyme profiles showed high variability among studied species. The UPGMA phenogram and genetic similarity analysis based on combination of seed morphology, protein, and isozyme patterns confirmed the extensive genetic diversity existed in Acacia species.]]>
p. 161−174
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