5篇
您的检索式：作者名="Mohammad HASSOUNA"
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| 1 | UV/Vis Characterization and Fate of Organic Amendment Fractions in a Dune Soil in Dakar, Senegal显示文摘The application of organic amendments on soils poor in organic matter(OM) can improve long-term soil fertility, but may also enhance the mineralization of native soil organic matter. Three organic amendments, compost, sewage sludge and horse manure, used by urban market gardeners in Dakar, Senegal were analyzed for their OM maturity. Their fate was evaluated in a 45-d agronomic trial in a sandy Arenosol with lettuce. In each case, water-extractable organic matter(WEOM) and humic-like substances(HLS)were isolated from raw amendments and amended soils, and characterized using ultraviolet-visible(UV/Vis) spectroscopy. Results highlighted the general more aromatic character of HLS and WEOM fractions extracted from compost compared to the other two amendments. When applied to soils, however, these differences were not clearly observed. The aromaticity and humification degree of the labile fraction(WEOM) increased with depth in the first 30 cm for all amendments. This indicated the high lixiviation rates that fresh OM underwent in the studied sandy soil. Finally, a statistical analysis of the results was able to discriminate between surface and deeper horizons and between amended- and non-amended soil samples. Spectroscopic indices showed indeed strong increase/decrease with depth linked with the mineralization/humification processes that the fresh OM from amendments underwent during the 45 d of the agronomic trial. This study highlights the potential of spectroscopic techniques to study agricultural amendment organic matter fractions and their fate in soils. | Silwan DAOUK Mohammad HASSOUNA Anne GUEYE-GIRARDET Seydou NIANG Hans-Rudolf PFEIFER | 2015 | Pedosphere2015，25，3： | 6 |
| 2 | Characterization of Rhamnolipid Produced by Pseudomonas aeruginosa Isolate Bs20显示文摘 | Ahmad Mohammad Abdel-Mawgoud Mohammad Mabrouk Aboulwafa Nadia Abdel-Haleem Hassouna | 2009 | Applied Biochemistry and Biotechnology2009，，2： | 1 |
| 3 | Characterization of Surfactin Produced by Bacillus subtilis Isolate BS5显示文摘 | Ahmad Mohammad Abdel-Mawgoud Mohammad Mabrouk Aboulwafa Nadia Abdel-Haleem Hassouna | 2008 | Applied Biochemistry and Biotechnology2008，，3： | 1 |
| 4 | Phospholipase C from Pseudomonas aeruginosa and Bacillus cereus:characterization of catalytic activity显示文摘Objective:To study characteristics of phospholipases C(PLCs),their importance for producing microorganisms us well us the potential of their use for industrial purposes.Methods:PLC from Bacillus cereus(B.cereus) D101 was selected as an example of Gram-positive PLCs and PLC from Pseudomanas aeruginosa(P.aeruginosa) D183 of Gram-negative ones.Enzymes were partially purified by ammonium sulfate precipitation followed by membrane dialysis.Partially purified preparations were used to study effect of different factors on activities as well as in substrate specificity tests which were conducted using a turbidimetric assay method.Results:Maximum activity was at pH 7 and 8 and 40 ℃ for P.aeruginosa PLC,and pH 8-10 and 37 ℃ for B.cereus PLC.Both PLCs were inhibited by Pi at 5 mM or higher,whereas,PLC from B.cereus only was inhibited by EDTA.Activity of P.aeruginosa PLC was not affected by removing Zn^(2+) ions from reaction mixture or their replacement with Ca^(2+),Ba^(2+),Mg^(2+) or Mn^(2+)ions.Vis-a-vis,activity of B.cereus PLC was found to be metal ion dependent PLCs from both isolates were relatively thermostable and showed maximum affinity toward phosphatidylcholine.Sphingomyelin and phosphatidylethanolamine were not good substrates and phosphatidylinositol,phosphatidylserine,phosphatidylglycerol and cardiolipin could be considered nonsubstrates.Conclusions:Human body physiological conditions could favor activity of P.aeruginosa and B.cereus PLCs.These enzymes may participate in phosphate scavenging and virulence of producing isolates but not in autolysis.PLCs from both isolates are potential candidates for industrial use. | Nooran Sherif Elleboudy Mohammad Mabrouk Aboulwafa Nadia Abdel-Haleem Hassouna | 2014 | Asian Pacific Journal of Tropical Medicine2014，7，11： | 1 |
| 5 | Optimization of surfaetin production by bacillus subtilis isolate BS5显示文摘 | ABDEL-MAWGOUD A Mohammad ABOULWAFA M Mabrouk HASSOUNA Nadia Abdel-Haleem | 2008 | Applied Biochemistry and Bioteehnology2008，150，3： | 1 |
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