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81.
The Egyptian Wolf Canis lupaster was recently rediscovered as a distinct species on the basis of both morphologic and molecular genetic evidence. Phenotypical variability, including coat colour of this species across its vast, ecologically diverse range is yet to be investigated. In this paper, we present the first record of melanistic individuals of this species and compare their morphological characters and mitochondrial cytochrome b DNA sequences with those of typically coloured Canis lupaster and other closely related canids to verify their identity. We also study pelage polymorphism in a population of this species in the Egyptian Nile Valley and the Nile Delta and define its different colour variants. The typical colour, as well as the rare, very light and reddish coat colours are described. We discuss the possibility that the observed coat colour polymorphism is the result of hybridisation with the domestic dog and their potential adaptive significance.  相似文献   
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83.
DNA was isolated from different histopathologic types and grades of human bladder carcinoma. The isolated DNA was submitted to quantitative determination and base composition analysis. A pilot study was done on the effect of gamma irradiation as a physical mutagen on characteristics of DNA in the examined tissues. Identity in the genetic components in the urinary bilharziasis snails and the human bladder cancer was observed. The same was observed in both intestinal bilharziasis snails and the cancerous intestinal tissues.  相似文献   
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85.
This study was carried out to evaluate the effect of electroejaculation (EEJ) on myocardial function, acid–base balance, and hematobiochemical profiles in male dromedary camels. Twenty sexually mature, apparently healthy male camels were assigned to EEJ. Parallel, eight naturally mated male camels were enrolled as a control group. Three blood samples were collected from each camel: just before (T0), directly after (T1), and 24 hours after (T2) EEJ or natural mating. The serum concentrations of the cardiac biomarker troponin I (cTnI), blood gas parameters, and hematobiochemical profiles were determined. Nineteen camels were ejaculated by the end of the second circuit and one by the end of the first circuit. In both groups, the mean heart and respiratory rates had increased significantly immediately after the procedure, but returned to normal values 24 hours after the procedure. The mean serum concentration of cTnI had increased significantly in all camels after EEJ, but not in controls. However, at 24 hours post-EEJ, the serum concentration of cTnI did not differ significantly compared with baseline values. The blood pH and base excess had decreased, and the PCO2 and lactic acid had increased after EEJ. The EEJ provoked decreases in hematocrit and mean corpuscular volume. In the control group, the base excess, HCO3, TCO2, anion gap, and lactic acid increased slightly after mating but did not reach a significant level compared with premating values. It is concluded that EEJ in camels results in a reversible myocardial injury, changes in the acid–base status, and increase the lactic acid concentration.  相似文献   
86.
Cultures of a strain of Amphidinium carterae Hulburt isolated from a eutrophic basin in Alexandria were investigated for the optimum growth conditions, including vitamin requirements, the assimilation index and the potential toxicity of this species. A division rate of 2.7 day–1, was reached on the second and third day under optimum conditions, with and without addition of B12 and biotin. The rate of C14 assimilation per unit chlorophyll ranged from 0.2 to 5.4 mgC.(mg Chla)-1.h–1 according to the growth conditions and to cell size. As the cell density increased in the cultures, the cell size decreased and their photosynthetic efficiency increased. Toxicity of A. carterae to brine shrimp resulted from grazing and not from membrane diffusion of extracellular toxins.  相似文献   
87.
Forty-day-old seedlings of Atriplex halimus were treated either with NaCl (50, 300 and 550 mM) for the subsequent 30 days or with 15% PEG for the subsequent 10 days. As much as 50 mM of NaCl significantly increased shoot fresh and dry weight and height; nevertheless, 300 or 550 mM NaCl seemed to have no effect. On the other hand, these growth parameters were not affected by drought after 3 or 6 days, but were reduced after 10 days. The gas exchange parameters (photosynthetic rate, stomatal conductance and transpiration rate) were increased by 50 mM NaCl, but decreased by 300 and 550 mM. These parameters were decreased in response to drought only after 10 days of withholding water. In contrast to Na+, K+ was significantly decreased by NaCl but not by drought. The time course effect revealed that phosphoenol pyruvate carboxylase (PEPC) protein was doubled in response to NaCl after 1 and 5 h and continued thereafter, higher than control, while drought had no significant effect. Rubisco seemed unchanged by NaCl or drought. It could be concluded that the decrease in fresh weight might be attributed to the decrease in water content. Moreover, the decrease in photosynthesis could result from a decrease in stomatal conductance, a protective mechanism against water loss to improve water use efficiency. These findings indicate that Atriplex halimus tolerates NaCl and drought through decreasing growth, reducing gas exchange parameters to improve water use efficiency, uptake Na+ and saving, if any, the photosynthetic enzyme particularly PEPC.  相似文献   
88.
The outcomes of compressed spinal cord injury (CSCI) necessitate radical treatment. The therapeutic potential of neuroectodermal stem cells (NESCs) in a rat model of CSCI in acute and subacute stages was assessed. White Wistar rat were divided into control, sham-operated, CSCI untreated model, CSCI grafted with NESCs at 1 day after CSCI, and at 7 days after CSCI. Primary NESC cultures were prepared from brains of embryonic day 10 (E10) mice embryos. NESCs were transplanted at the site of injury using a Hamilton syringe. Locomotor functional assessment, routine histopathology, immunostaining for (GFAP), and ultrastructure techniques for evaluating the CSI were conducted. In CSCI, areas of hemorrhage, cavitation, reactive astrocytosis, upregulated GFAP expression of immunostained areas, degeneration of the axoplasm and demyelination were observed. One day after grafting with NESCs, a decrease in astrocyte reaction and pathological features, quantitative and qualitative enhancement of remyelination and improved locomotor activity were observed. Treatment with NESCs at 7 days after CSCI did not mitigatethe reactive astrocytosis and glial scar formation that hindered the ability of the NESCs to enhance remyelination of axons. In conclusion, the microenvironment and time of NESCs transplantation affect activity of astrocytes and remyelination of axons.  相似文献   
89.
Phylogenetic diversity and ecological features in the Egyptian flora   总被引:6,自引:0,他引:6  
Until fairly recently, regional-scale ecological and evolutionarypatterns have tended to be ignored as conservation efforts have been concernedwith species and their habitats. Here we compare frequencies in the Egyptianflora of particular rank sizes (order, family and genus) with patterns ofspecies abundance (classified as very rare, rare, common, or very common) and anarray of life-history attributes. The angiosperm flora of Egypt is representedby 2446 taxa (2088 species), including taxa in 10 subclasses, 51 orders, 120families, and 742 genera. A high degree of monotypism was observed: four ordersare monotypic (each existing as single species), and have very rare overallabundances; 30 families are monotypic (17 of which are very rare or rare); and 354genera are monotypic (over 70% of which are very rare or rare). Fourteenfamilies (in particular the Resedaceae and Zygophyllaceae) have at leastone-fifth of their global species represented in the Egyptian flora. Introducedspecies in general, and tree, aquatic herb and liana life forms all are especially well represented among monotypic genera. Native taxa are highlyrepresented among rare and very rare abundance classes, while introduced taxadid not differ significantly in their abundance patterns, compared to overallflora values. Few large genera (>20 spp.) occur in the flora, with mostspecies concentrated in genera containing 8–19 species per genus.Similarly, few families were highly speciose. Annual and herbaceous species weresignificantly over-represented, mainly among large, speciose genera andfamilies. However, perennials, trees, shrubs, aquatic herbs, lianas and parasiticspecies were found mainly in families and genera having very few taxa.Life-history attributes may have important implications to speciation rates.Taxonomically based results, involving abundances and life-history attributes,are discussed in the context of biodiversity and conservation.  相似文献   
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