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1.
Osama H. Sayed Yahya S. Masrahi M. Remesh B.S. Al-Ammari 《Saudi Journal of Biological Sciences》2019,26(7):1911-1914
Work aimed at assessing status and introducing water conservation regimes for coffee production in southern Saudi Arabian highlands. Data on farm locations, altitudes, areas, practices, irrigation, tree density, and annual coffee production were analyzed. Field experiment using chlorophyll fluorescence and different irrigation regimes was conducted to examine effects of reducing irrigation frequency on photosynthesis. Results indicated that Coffea arabica L. is commonly grown at altitudes of 1300–1400 m. Plants grown at 4–6 Trees m?2 using 100 kg ha?1 mineral fertilizer produce an average of 3 t ha?1. High frequency 2-day-intervals irrigation regime practiced by farmers during the dry season presents ecological challenge to limited local artesian water resources. Changes in chlorophyll fluorescence under 14-day-intervals irrigation regime initiated water stress that markedly inhibited Photosystem II efficiency and quantum yield and increased non-photochemical energy dissipation. Applying a 7-day-intervals irrigation regime induced less inhibitory effects on Photosystem II. Results also indicated that shifting from 2-day-intervals irrigation regime to 7-day-intervals regime improves coffee agroecology and directs coffee production towards sustainability. 相似文献
2.
Abdulrazak Osama Han Ming Gan Cindy Shuan Ju Teh Kien-Pong Yap Kwai-Lin Thong 《Journal of bacteriology》2012,194(24):6933
The genome sequence analysis of a clinical Vibrio cholerae VC35 strain from an outbreak case in Malaysia indicates multiple genes involved in host adaptation and a novel Na+-driven multidrug efflux pump-coding gene in the genome of Vibrio cholerae with the highest similarity to VMA_001754 of Vibrio mimicus VMA223. 相似文献
3.
Uptake of ferrous iron histidinate, a promoter of lipid peroxidation, by Ehrlich ascites tumor cells 总被引:1,自引:0,他引:1
The kinetics of the uptake of Fe(II)-histidinate, a known promoter of lipid peroxidation, into Ehrlich ascites tumor (EAT) cells and the intracellular binding of iron were studied in vitro. EAT cells (27.10(6)/ml) were incubated in Hanks' balanced salts solution at 37 degrees C for various time intervals in the presence of FeSO4 (1 mM) and L-histidine (10 mM). Total iron was determined by the 1,10-phenanthroline/ascorbate method and ferric iron by reaction with 5-sulfosalicylic acid; the difference was ascribed to ferrous iron. Total iron decreased rapidly in the medium (242 nmol within the first 10 min), and a corresponding increase of total iron (saturation value 376 nmol after 60 min) was determined within the cells, after the cellular proteins had been solubilized with 6 M urea. In the absence of EAT cells, Fe(II)-histidinate was readily oxidized to Fe(III)-histidinate by oxygen, but this reaction was strongly retarded by the tumor cells. The uptake of iron histidinate occurred in the oxidized state, while an uptake of ferrous iron could not be proven unambiguously. When EAT cells were saturated with iron, it was found that 93% of intracellular iron was bound to water-insoluble proteins and 7% was associated with soluble proteins, while no unbound iron was detectable by the method used. It was concluded that, despite the high uptake of total iron, only a very small portion of the intracellular iron was available as a redox catalyst for lipid peroxidation. 相似文献
4.
H Osama S Narumiya O Hayaishi H Iinuma T Takeuchi H Umezawa 《Biochimica et biophysica acta》1983,752(2):251-258
The activities of rat brain prostaglandin D synthetase and swine brain prostaglandin D2 dehydrogenase were inhibited by some saturated and unsaturated fatty acids. Myristic acid was most potent among saturated straight-chain fatty acids so far tested. The IC50 values of this acid were 80 microM for prostaglandin D synthetase and 7 microM for prostaglandin D2 dehydrogenase, respectively. Little inhibition was found with methyl myristate and myristyl alcohol. The IC50 values of these derivatives were more than 200 microM for both enzymes, suggesting that the free carboxyl group was essential for the inhibition. The effects of cis double bond structure of fatty acids on the inhibition potency were examined by the use of the carbon 18 and 20 fatty acids. The inhibition potencies for both enzymes increased with the number of cis double bonds; the IC50 values of stearic, oleic, linoleic and linolenic acid were, respectively, more than 200, 60, 30 and 30 microM for prostaglandin D synthetase, and 20, 10, 8.5 and 7 microM for prostaglandin D2 dehydrogenase. Arachidonic acid also inhibited the activities of both enzymes with respective IC50 values of 40 microM for prostaglandin D synthetase and 3.9 microM for prostaglandin D2 dehydrogenase, while arachidic acid showed little inhibition. The kinetic studies with myristic acid and arachidonic acid demonstrated that the inhibition by these fatty acids was competitive and reversible for both enzymes. Myristic acid and other fatty acids also inhibited the activities of several enzymes in prostaglandin metabolism, although to a lesser extent. The IC50 values of myristic acid for prostaglandin E isomerase, thromboxane synthetase and NAD-linked prostaglandin dehydrogenase (type I) were 200, 700 and 100 microM, respectively. However, this fatty acid showed little inhibition on fatty acid cyclooxygenase (20% at 800 microM), glutathione-requiring prostaglandin D synthetase from rat spleen (20% at 800 microM), and NADP-linked prostaglandin dehydrogenase (type II) (no inhibition at 200 microM). 相似文献
5.
Neutron-induced γ-ray emission tomography for quantitative determination of the concentration and distribution of elements
in a selected plane through a biological specimen is briefly explained and applied by way of illustration to the analysis
of gallstones. A system capable of carrying out studies of the binding site of75Se in different matrices using time differential perturbed angular correlation spectroscopy is also briefly described. Developments
in the detector technology of positron emission tomography have allowed small-diameter imaging devices to be built for in
vivo preclinical evaluation of new tracers in small animals and are discussed in the context of a proposed experiment combining
the techniques mentioned above. 相似文献
6.
Dr. Sherif M. H. Sanad Alshimaa A. M. Abdelsalam Aya A. Gamal Eldin Esraa H. Abdelfattah Fatma R. M. Hussein Nada G. Mohammed Nariman A. S. Taha Prof. Dr. Ahmed E. M. Mekky 《化学与生物多样性》2023,20(6):e202300546
An efficient protocol was adopted to efficiently prepare three new series of bis(pyrazolo[1,5-a]pyrimidines) linked to different spacers. The new bis(pyrazolo[1,5-a]pyrimidines) were prepared in 80–90 % yields by reacting the respective bis(enaminones) and 4-(4-substituted benzyl)-1H-pyrazole-3,5-diamines in pyridine at reflux temperature for 5–7 h. The new products showed a wide spectrum of antibacterial activity against six different bacterial strains. In general, propane- and butane-linked bis(pyrazolo[1,5-a]pyrimidines), which are attached to 3-(4-methyl- or 4-methoxybenzyl) units, had the best antibacterial activity with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values up to 2.5 and 5.1 μM, respectively. Additionally, the previous products demonstrated promising MurB inhibitory activity with IC50 values up to 7.2 μM. 相似文献
7.
NADPH-dependent 20α-hydroxysteroid oxidoreductase (20α-HSD; EC 1.1.1.149) from bovine fetal erythrocytes was obtained for the first time free of hemoglobin by a new 2,500-fold purification scheme. This was achieved by a sequence of calcium phosphate gel adsorption, ammonium sulfate fractionation, and affinity chromatography. The present results lead us to believe that the NADPH-dependent 3β-hydroxysteroid oxidoreductase activity, which was co-purified with 20α-activity, may originate at the active site of 20α-HSD (2). 相似文献
8.
A series of aroyl- and aryl-hydrazide derivatives was prepared from d-glycero-d-gulo-heptono-1,4-lactone (1). The reactivity of the NH proton in these hydrazides, in terms of their dissociation constants (pKa), was determined from their electronic spectra, and correlated to the Hammett σ values of the substituents. Comparable reactivities of the NH protons for the compounds, and the effect of the substituent, were studied by n.m.r. spectroscopy. Decomposition of the aroylhydrazides with copper(II) sulfate or nitrous acid resulted in the regeneration of 1. 相似文献
9.
Summary The cellulases of two mould fungi namely Penicillium oxalicum Curie et Thom and Helminthosporium cyclops Drechsler were precipitated either by organic solvents or inorganic salts. Acetone seems to be the most suitable precipitant for these enzymes. The action of some factors including temperature, pH value, enzyme concentration and reaction time on the enzymatic activity was also investigated. 相似文献
10.
Naeema A. Akbar Abdullah M. Assiri Omima I. Shabouni Osama M. Alwafi Rajaa Al-Raddadi Mohamad H. Alzahrani Esam I. Azhar Ashraf Amir Abdullah M. Aljiffri Abdulhakeem O. Althaqafi 《PLoS neglected tropical diseases》2020,14(11)
Rapid urbanization, global trade, and the exceptionally great numbers of worldwide visitors during Hajj and Umrah have all placed the Kingdom of Saudi Arabia at a significant risk of introducing several vector-borne tropical diseases, such as dengue fever virus (DENV) infection. In this study we estimated DENV infection cost of illness (COI) in Saudi Arabia in the period 2013–2017, by processing national data including all declared cases recorded in referral centers in the western region, being the endemic region of the country. Using a statistically validated predictive model that was built on a representative sample of 717 laboratory-confirmed cases of DENV infection, direct costs, due to care-related expenditures, were estimated by applying the predictive equation to national data. However, indirect costs, which are due to productivity loss, were estimated using the human capital model based on gross domestic product adjusted for invalidity duration. Further, under-reporting was adjusted by using an expansion factor EF = 3. We observed highest estimated costs in 2016 with over US$168.5 Million total costs, including direct (US$29.0 Million) and indirect (US$139.5 Million) costs, for a total 4415 confirmed cases. The total DENV COI for the five years was estimated as US$551.0 Million for a total 15,369 patients (59.7%) out of 25,745 declared cases, resulting in an average cost of US$11 947.6 by patient. Depending on the year, productivity years loss costs accounted for 63.3% to 83.8% of the estimated total costs. Dengue has a substantial local economic burden that costs US$110.2 Million per year, stressing the urgent need for an effective national prevention strategy to perform considerable cost-savings besides reducing morbidity. 相似文献