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1.
Phytoplankton production and respiration in the Blue Nile and White Nile at Khartoum were measured during the period November 1969–January 1971 using the light and dark bottle technique. Maximum rates of production coincided with periods of maximum phytoplankton densities. In the Blue Nile gross production varied between 0.00 gCm–3d–1 during the flood season and 2.19 gCm–3d–1 (0.49 mgO2l–1h–1) during November 1969. In the White Nile the range was from 0.41 gCm–3d–1 (0.09 MgO2l–1h–1) in May to 3.74 gCm–3d–1 (0.83 MgO2l–1h–1) in November. The maximum rates of respiration in the Blue Nile and White Nile were 0.10 and 0.63 MgO2l–1h–1 respectively. The ratios net:gross production were generally higher in the White Nile than in the Blue Nile. 相似文献
2.
The venous system of Polypterus exhibits general asymmetry. The features that characterize the venous system of this peculiarly African fish are the possession of many blood sinuses, the segmental drainage of blood, the continuation of the posterior cardinal veins as separated vessels and the occurrence of several anastomozes between the latter.
In the absence of any recent comprehensive work on the blood system of this fish, it was thought that investigation of the circulatory system of Polypterus would be valuable. In this paper attention is drawn to Budgettapos;s (1902) original work on a larva of Polypterus senegalus. Contrary to Budgettapos;s findings it is concluded that what he called the "interrenal" vein is in fact the right posterior cardinal vein. It is also found that paired posterior cardinal veins exist in all adults. 相似文献
In the absence of any recent comprehensive work on the blood system of this fish, it was thought that investigation of the circulatory system of Polypterus would be valuable. In this paper attention is drawn to Budgettapos;s (1902) original work on a larva of Polypterus senegalus. Contrary to Budgettapos;s findings it is concluded that what he called the "interrenal" vein is in fact the right posterior cardinal vein. It is also found that paired posterior cardinal veins exist in all adults. 相似文献
3.
Eya Khemis Mayssa Ben Mustapha Ikbel Chaieb Roberta Ascrizzi Guido Flamini Abdel Halim Harrath Hichem Ben Jannet Afifa Zardi-Bergaoui 《化学与生物多样性》2023,20(2):e202200646
Due to the several side effects of synthetic pesticides, including environmental pollution, threats to human health, and the development of pest resistance to insecticides, the use of alternative healthy, available and efficient agents in pest management strategies is necessary. Recently, the use of essential oil obtained from aromatic plants has shown significant potential for insect pest management. For this reason, the essential oil isolated from seeds of Thapsia garganica L. was investigated for the first time for its chemical profile, and its toxicity and repellency effects against Tribolium castaneum adults. Qualitative and quantitative analyses of the chemical composition by gas chromatography coupled to mass spectrometry (GC/MS) revealed the presence of 18 organic volatiles representing 96.8 % of the total constituents. The main compounds were 1,4-dimethylazulene (51.3 %) followed by methyl palmitate (8.2 %), methyl linoleate (6.2 %) and costol (5.1 %). Concerning the repellent effect, results revealed that SEO (Seed Essential Oil) was very repellent towards T. castaneum adults, with 100 % repellency after 2 h of exposure. Furthermore, the essential oil exhibited remarkable contact toxicity against T. castaneum (93.3 % of mortality) at the concentration of 10 % (v/v). The median lethal dose (LD50) of the topical application of the seed essential oil was 4.4 %. These encouraging outcomes suggested that the essential oil from T. garganica seeds could be considered a potent natural alternative to residual persistent and toxic insecticides. 相似文献
4.
5.
The effects of salt stress on nitrogenase (N2-ase) activity, growth and nitrogen content ofVicia faba (L.),Medicago sativa (L.) Merrill,Glycine max andVigna sinensis (L.) were investigated. Four levels of salinity were applied and salt treatments were imposed on inoculated and N-fertilized plants.M. sativa tolerated mild levels of salinity but higher salt concentrations depressed N2-ase activity of this species. The other three legumes were considerably affected by salt treatments, and N2-ase activity was significantly reduced by salinity. Vicia faba, carrying elongate nodules, could restore a partial N2-ase activity upon recovery from salt stress whereasG. max andV. sinesis, both with spherical nodules, could not regain significant activity when salinity was removed. Salt stress retarded growth of both inoculated and N-fertilized plants. The nitrogen content of both treatments was also affected by salinity and the effect was more severe for inoculated than N-fertilized plants. 相似文献
6.
The Next-Generation Sequencing (NGS) platforms produce massive amounts of data to analyze various features in environmental samples. These data contain multiple duplicate reads which impact the analyzing process efficiency and accuracy. We describe Fast-HBR, a fast and memory-efficient duplicate reads removing tool without a reference genome using de-novo principles. It uses hash tables to represent reads in integer value to minimize memory usage for faster manipulation. Fast-HBR is faster and has less memory footprint when compared with the state of the art De-novo duplicate removing tools. Fast-HBR implemented in Python 3 is available at https://github.com/Sami-Altayyar/Fast-HBR. 相似文献
7.
Nada H. El-Dershaby Soad A. El-Hawash Shaymaa E. Kassab Hoda G. Dabees Ahmed E. Abdel Moneim Ibrahim A. Abdel Wahab Mohammad M. Abd-Alhaseeb Mostafa M. M. El-Miligy 《Journal of enzyme inhibition and medicinal chemistry》2022,37(1):1737
A new series of co-drugs was designed based on hybridising the dihydropteroate synthase (DHPS) inhibitor sulphonamide scaffold with the COX-2 inhibitor salicylamide pharmacophore through biodegradable linkage to achieve compounds with synergistic dual inhibition of COX-2/PGE2 axis and DHPS enzyme to enhance antibacterial activity for treatment of septicaemia. Compounds 5 b, 5j, 5n and 5o demonstrated potent in vitro COX-2 inhibitory activity comparable to celecoxib. 5j and 5o exhibited ED50 lower than celecoxib in carrageenan-induced paw edoema test with % PGE2 inhibition higher than celecoxib. Furthermore, 5 b, 5j and 5n showed gastric safety profile like celecoxib. Moreover, in vivo antibacterial screening revealed that, 5j showed activity against S.aureus and E.coli higher than sulfasalazine. While, 5o revealed activity against E.coli higher than sulfasalazine and against S.aureus comparable to sulfasalazine. Compound 5j achieved the target goal as potent inhibitor of COX-2/PGE2 axis and in vivo broad-spectrum antibacterial activity against induced septicaemia in mice. 相似文献
8.
Mukhtar Ahmed Daoud Ali Abdel Halim Harrath Tajamul Hussain Nasser Al-Daghri Majed S. Alokail Ravindranath H. Aladakatti Mukhtar Ahmed G. Ghodesawar 《Comptes rendus biologies》2014,337(4):250-257
Boswellia papyrifera and Boswellia carterii diffuses smoke polluting air that adversely affects indoor environment that certainly harm human health. Therefore, this study aims at ascertaining the effect of these plants on gonadal hormones and molecular changes in rat spermatozoa. The animals were exposed to 4 g/kg body weight of B. papyrifera and B. carterii daily for 120 days along with suitable controls. Significant decreases in FSH, LH and testosterone levels were evidenced, along with a reduction of protein, sialic acid, and carnitine levels. In sperm physiology, sperm count, motility, speed decrease, whereas sperm anomalies increase. TEM observation indicates morphological changes in plasma and acrosomal membranes, cytoplasmic droplet in the tail region, vacuolated, and disorganization of the mitochondrial sheath. These findings demonstrate that B. papyrifera and B. carterii smoke affects the process of sperm formation and maturation, which indicates the detrimental effects of these plants on the reproductive system. 相似文献
9.
Glucosidation of the new 8-amino-6-benzyl(or substituted benzyl)-2,8-dihydro-1,2,4-triazolo[4,3-b][1,2,4]triazin-7(3H)-ones (3a-d) with 2,3,4,6-tetra-O-acetyl-alpha-D-glucopyranosyl bromide 4 gave the corresponding N-glucosides 5a-d. Chemical transformations leading to new functionalities have also been achieved to give compounds 7-12. Antimicrobial activity of compounds 5a-c against Aspergillus fumigatus, Penicillium italicum, Syncephalastrum racemosum, Candida albicans, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, Escherichia coli is described. 相似文献