Several toxigenic cyanobacteria produce the cyanotoxin (microcystin). Being a health and environmental hazard, screening of water sources for the presence of microcystin is increasingly becoming a recommended environmental procedure in many countries of the world. This study was conducted to assess the ability of freshwater cyanobacterial species Westiellopsis prolifica to produce microcystins in Iraqi freshwaters via using molecular and immunological tools. The toxigenicity of W. prolifica was compared via laboratory experiments with other dominant bloom-forming cyanobacteria isolated from the Tigris River: Microcystis aeruginosa, Chroococcus turigidus, Nostoc carneum, and Lyngbya sp. significant expression of mcyE gene and microcystin production was most evident in W. prolifica. Contrary to the prevailing concept that M. aeruginosa is a main microcystin producer in freshwaters around the world, no significant microcystin production was observed with this species throughout the time points studied in our laboratory methods. As for C. turigidus, N. carneum and Lyngbya sp., neither mcyE expression nor microcystin production was significant. Data from mcyE expression by RT-qPCR were generally in agreement with those obtained from microcystin quantification by ELISA. Interestingly, W. prolifica, which showed clear microcystin-producing ability in this study and which was not reported before in the literature to produce microcystin, can be added as a new microcystin producer to the list of toxigenic cyanobacteria.
ترك السلطان عبدالحميد الثاني بصماتهُ على أخاديد الزمان وعلى خارطة المشرق العربي الخاضع للسيطرة العثمانية أنذاك ، لكونهُ أهم شخصية أسلامية غير عربية واجهت الخطر الصهيوني ومحاولاتهم الإستيطانية في مشرق الوطن العربي ، على الرغم من صعوبة الظروف التي كانت تمر بها الدولة العثمانية داخليا ً وخارجيا ً، بما فيها من أطماع اقتسامها بين الاوربين ولذا سموها بالرجل المريض .
المُستلخص:
يتناول هذا البحث موضوعاً يتركز في جانب تحديد مفهوم ومحتوى الإستراتيجية. وقد أشارت الأدبيات إلى عدد من المحاولات التي هدفت إلى تلمس مفهوم ومحتوى الإستراتيجية في منظمات الأعمال، غير أن تلك المحاولات- على الرغم من ندرتها- كانت تتسم بغلبة الأطر النظرية والتعبير عن المفهوم، بالإستناد إلى حوارات فكرية وإرهاصات ذات علاقة بمفهوم ومحتوى الإستراتيجية.
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... Show Moreتلعب الاعتمادات المستندية دوراً كبيراً وخطيراً في التجارة الدولية باعتبارها إحدى أوسع أدوات الدفع انتشاراً في العالم سواءاً كان ذلك بالنسبة للمستورد أم للمصدر وتغطيتها للمخاطر المحتملة لكلا الطرفين، فهي تؤمن للمصدر استلام قيمة البضاعة بالكامل عند تنفيذها لشروط العقد، ويسمح للمستورد بعدم الدفع إلا بعد إتمام شحن البضاعة وتقديم المستندات المطلوبة واستلامها.
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... Show MoreIn this research investigation, a total of eighteen diverse tetra- and penta-lateral cyclic compounds were synthesized. These included 1,3,4-thiadiazole, thiazolidin-4-one (via an alternative method), 1,2,4-triazole, carbothioamide, thiazole-4-one, azetidin-2-one, and oxazole. The synthesis procedure entailed a sequence of reactions. The thiazolidine-4-one 1 was obtained by reaction p-aminobenzoic acid with thiosemicarbazide, followed by treatment with p-tolualdehyde to produce Schiff base 2. Reaction Schiff base 2 with mercaptoacetic acid in dry benzene was carried out to produce thiazolidine-4-one 3. In another synthesis pathway, the esterification of p-nitro benzoic acid with ethanol in the presence of sulfuric acid was
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... Show Moren this work, the adsorption of crystal violet dye from aqueous solution on charcoal and rice husk has been investigated, where the impact of variable factors (contact time; the dosage of adsorbent, pH, temperature, and ionic strength) have been studied. It has been found that charcoal and rice husk have an appropriate adsorption limit with regards to the expulsion of crystal violet dye from fluid arrangements. The harmony adsorption is for all intents and purposes accomplished in 45 min for charcoal and 60 min for rice husk. The amount of crystal violet dye adsorbed (0.4 g of charcoal and 0.5 g of rice husk) increased with an increasing pH and the value of 11 is the best. The effect of temperature on the adsorption process was studied
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