Antimicrobial susceptibility of non-O1 Vibrio cholerae isolated from wastewater stabilization ponds in Marrakesh,Morocco

The 365 strains of Vibrio cholerae, isolated in Marrakesh from raw sewage and stabilization pond effluent, were all identified as non-O1 Vibrio cholerae. When tested for their susceptibilities to ampicillin, amoxicillin, cephalothin, streptomycin, novobiocin, chloramphenicol, nalidixic acid and trimethoprim-sulphamethoxazole, 13% of the strains from raw sewage and 20% of those from stabilization pond effluent were found to be resistant to one or more of the antibiotics. There were no significant differences, in terms of drug resistance, between isolates from the new sewage and those from the ponds' effluent.The authors are with the Université Cadi Ayyad, Faculté des Sciences Semialia, Département de Biologie, Laboratoire de Microbiologie, BP S/15, Marrakesh, Morocco     

Seasonal incidence of and antibiotic resistance among Aeromonas species isolated from domestic wastewater before and after treatment in stabilization ponds

The efficiency of stabilization pond treatment of domestic wastewater in removing culturable cells of motile Aeromonas and its influence on the incidence of resistance to seven antibiotics were investigated in this study. Removal efficiency was higher (P < 0.001) in the warm months (98.8%) than in the cold months (97%). Among the 264 isolates, 163 were Aeromonas caviae, 24 were A. hydrophila, and 54 were A. sobria. Twenty-three isolates could not be identified to the species level. In the influent, A. caviae dominated in both cold and warm months. In the water samples originating from the influent, A. sobria was present at higher percentages in the warm period. All the isolates were resistant to amoxicillin and most of them (73%) exhibited resistance to cephalothin. Of the three species tested, A. sobria was more susceptible to antibiotics than either A. caviae or A. hydrophila. The most striking difference among the species was seen in resistance to cephalothin. There were 91 % of A. caviae strains and 96% of A. hydrophila isolates that were resistant to cephalothin. However, only 9% of A. sobria strains exhibited resistance to this drug. The high incidence of resistance in raw sewage was connected with a high proportion of A. caviae, whereas in the water samples collected from the effluent during the warm months, a high proportion of A. sobria decreased the total amount of multiple-resistant bacteria. Results demonstrated the need for identification to the species level.Offprint requests to: L. Hassani.     

Luteinizing and ovulatory action of oestradiol in the pregnant rat

Oestradiol injection on Day 10 of pregnancy in rats, resulted in either ovulation or luteinization in 50% of cases on Day 12. Cytological data showed that the number of pituitary LH cells decreased significantly on Day 11 in all oestradiol-treated animals whether responsive or not to oestrogen by ovarian modifications, while the number of pituitary FSH cells only decreased significantly in females with characteristic ovarian signs of preovulation. Bioassay of pituitary FSH confirmed the cytological data. It is concluded that ovulation and luteinization only occurred in the pregnant rat when oestradiol triggered off a synchronous release of LH and FSH.     

New Insight into the Interactions of Arbutin with Mushroom Tyrosinase

The Protein Journal - As a safe substitute for hydroquinone, β-arbutin, a natural plant substance, and its synthetic counterpart, α-arbutin, are used in depigmentation formulations....     

Depositional environment of the Upper Cretaceous orbitolinid-rich microfacies in the Kuh-e Mazar anticline (Kerman Province,Central Iran)

This study is focused on the depositional model and paleoenvironmental distribution patterns of orbitolinids-rich microfacies in an Upper Cretaceous carbonate succession in the Kuh-e Mazar anticline in Kerman Province, Central Iran. Twelve microfacies indicating a tidal flat (including intertidal and supratidal) and an inner ramp (consisting of subtidal lagoon and orbitolinid–rudist barrier shoal) belonging to a shallow-water ramp-type carbonate platform were recognised. Generally, the orbitolinid associations in the carbonate ramp are indicative of shallow warm waters with normal salinity. The occurrence and abundance of thick or conical orbitolinids in both shoal and lagoon show that such associations were well adapted to different environmental conditions including different depth, substrate stability and water energy. The slightly discoidal, almost discoidal and discoidal forms were only present in the deeper depths of the environment including the lagoon with muddy and more stable substrates and lower water energy. However, the orbitolinids in the inner part of the carbonate ramp were scarce or almost absent in the deep inner to middle lagoon due to the deep restricted environmental conditions unfavourable for benthic marine life.     

Task scheduling algorithms for energy optimization in cloud environment: a comprehensive review

Cluster Computing - Cloud computing is very popular because of its unique features such as scalability, elasticity, on-demand service, and security. A large number of tasks are performed...     

Ultrastructural studies on nodules induced by pyrimidine auxotrophs of Sinorhizobium meliloti

Twenty three pyrimidine auxotrophs of Sinorhizobium meliloti Rmd201 were generated by random mutagenesis with transposon Tn5. On the basis of biochemical characters these auxotrophic mutants were classified into car, pyrC and pyrE/pyrF categories. All auxotrophs induced white nodules which were ineffective in nitrogen fixation. Light and electron microscopic studies revealed that the nodules induced by pyrC mutants were more developed than the nodules of car mutants. Similarly the nodules induced by pyrE/pyrF mutants had more advanced structural features than the nodules of pyrC mutants. The nodule development in case of pyrE/pyrF mutants was not to the extent observed in the parental strain. These results indicated that some of the intermediates and/or enzymes of pyrimidine biosynthetic pathway of S. meliloti play a key role in bacteroidal transformation and nodule development.