首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   17篇
  免费   1篇
  2022年   1篇
  2016年   1篇
  2013年   1篇
  2011年   3篇
  2010年   1篇
  2002年   1篇
  2001年   1篇
  2000年   2篇
  1984年   1篇
  1982年   1篇
  1976年   1篇
  1969年   1篇
  1968年   1篇
  1967年   1篇
  1966年   1篇
排序方式: 共有18条查询结果,搜索用时 15 毫秒
1.
Rapid method of in vitro multiplication of date palm was developed. Shoot tips were cultured on Murashige and Skoog (MS) medium supplemented with 2 mg dm–3 dimethylaminopurine (2iP) + 1 mg dm–3 naphthalene acetic acid (NAA). Shoot buds were proliferated from white nodular cultures on hormone free medium. Shoot bud proliferation strongly enhanced when cultured on MS-medium contained 3 mg dm–3 2iP + 0.5 mg dm–3 NAA. Culturing on full-strength MS medium showed higher multiplication rate compared with half-strength MS medium. Among four concentrations of sucrose used, 30 g dm–3 speeded up the bud proliferation more than 10, 20 and 40 g dm–3. However, the largest shoot buds were observed with 40 g dm–3 sucrose. Solidification of culture media by 1.75 g dm–3 Phytagel showed the highest proliferation rate, but the largest buds were observed with 1 g dm–3 Phytagel.  相似文献   
2.
Summary At high salinities and high temperatures, the growth rate of Pterocladia was high, the tips of branch initials were dilated and holdfasts broadened. By the end of the fourth week bleaching of the whole plant was complete.Under low salinities and low temperatures, the rate of vegetative growth was decreased, the cuticle was thin and food reserve was centrally accumulated in the cells.Under high salinities and low temperatures, the rate of growth was greatly reduced and cells were devoid of food reserve. Defoliation of lateral branches was frequent.Under low salinities and high temperatures, the rate of growht was rather high and cells were relatively large.  相似文献   
3.
A simple systems for in vitro storage of health asparagus germplasm was developed. High percent (90 %) of shoots cultured in a standard multiplication medium were maintained viable in vitro at 5 °C in darkness for 12 months. This percent was decreased to 60 % when cultures were stored for 18 months. At normal temperature, shoots and callus cultures also survived for 1 year under osmotic stress on medium containing 40 g dm-3 mannitol.  相似文献   
4.
Thirty new aryl-pyridazinone-substituted benzenesulphonylurea derivatives (IXXX) were synthesized and evaluated for their anti-hyperglycaemic activity in glucose-fed hyperglycaemic normal rats. Twenty-three compounds (IIIXI, XIVXVII, XIXXXIV, XXVI and XXVIIIXXX) showed more or comparable area under the curve (AUC) reduction percentage (ranging from 21.9% to 35.5%) as compared to the standard drug gliclazide (22.0%). On the basis of docking results, 18 compounds were screened for their in vitro ability to inhibit rat lens aldose reductase. Ten compounds (IIIVI, XII, XVIXVIII, XXI and XXVII) showed ARI activity with IC50 ranging from 34 to 242?μM. Out of these, two compounds IV and V showed best ARI activity which is comparable with that of quercetin. As a result, two compounds (IV and V) possessing significant dual action (anti-hyperglycaemic and aldose reductase inhibition) were identified and may be used as lead compounds for developing new drugs.  相似文献   
5.
The antifungal efficacy of Ficus sycomorus and Pergularia tomentosa plant extracts on Bufo regularis experimentally infected with Aspergillus niger was studied. After an oral administration of the pathogen for 15 days, the blood, kidney and liver were examined. Treatment with A. niger produced a reduction in red blood count cells and hemoglobin content. Also, both livers and kidneys revealed marked destruction and degenerative changes. These changes included congestion of blood vessels, leukocytic infiltration, and cytoplasmic vacuolization of the hepatocytes. As well as complete destruction of the cellular boundaries of the tubular epithelia, inflammatory leukocytes between the intertubular spaces, destruction and necrosis in renal tubule cells and the swollen glomeruli with wide glomerular spaces were seen. Pretreatment with F. sycomorus and P. tomentosa plant extracts 1 h prior the administration of A. niger for two weeks improved blood parameters and protected against hepatic and renal damage as observed from histological examination and reduced spore numbers in culture media on these organs.  相似文献   
6.
Bradykinin and its related peptides are widely distributed in venomous animals, including scorpion. A peptide fraction isolated from the venom of the Egyptian scorpion Buthus occitanus was proved to have a bradykinin-potentiating activity. The aim of the present study was conducted to investigate whether the treatment with bradykinin potentiating factor (BPF) offers more beneficial effects in reversing cadmium-induced oxidative stress in rat liver and kidney. Adult male rats, equally divided into control and two treated groups, 10 animals in each group. group (I) was orally given (1 ml) saline and served as a control group; group (II) of rats was given cadmium chloride (4 mg/kg) alone, once daily an oral dose for 7 successive days; group (III) of rats was given ip injection (1 ml) BPF, once daily a dose for 7 successive days prior to CdCl2 treatment and on the next 7 successive days with the same dose of cadmium as group II. Both organs were subjected to histopathological analysis with the light microscope. The activities of alanine aminotransferase (ALT), asparate aminotransferase (AST) and alkaline phosphatase (ALP) in serum were measured as indicators of the liver function. As parameters of the kidney function, creatinine, uric acid and urea concentrations in serum were determined. Also, malondialdehyde (MDA), reduced glutathione (GSH), super oxide dismutase (SOD) and catalase (CAT) were determined in both tissues. Cd exposure caused a significant decrease or inhibition in the activities of GSH, SOD, and CAT, with significant increase in the level of MDA, in versus to control groups in both liver and kidney. Also, when Cd was treated in co-administration with BPF induced increase or stimulation in the activity of GSH, SOD, and CAT, with significant decrease in the level of MDA when compared to Cd group in both organs. Histopathological changes of liver and kidney were also in accordance with the biochemical findings. Our data showed that Cd treatment induced histopathological alteration in the liver, severe hydropic degeneration in centrolobular zones. Inflammatory cells infiltration around the congested central vein and an obvious injury in some renal tubules. Bradykinin potentiating factor (BPF) administration prevented the histopathological alterations which observed in Cd-groups and both liver and kidney had essentially normal appearance in histopathological examination. In conclusion, BPF markedly ameliorated cadmium-induced liver and kidney tissue damage as evidenced by histological and biochemical examinations and acts as a potent scavenger of free radicals to protect the liver and kidney against the deleterious effect of acute cadmium intoxication.  相似文献   
7.
Drug-resistant Mycobacterium tuberculosis (DR-MTB) is a major health threat to human beings. This study aimed to evaluate the prevalence and drug resistance profile of MTB. Data were collected from 2,296 newly diagnosed, and 246 retreated tuberculosis (TB) patients who attended the Advisory Clinic for Chest Diseases and Respiratory in Basra province from January 2016 to December 2020. Both new diagnostic and retreated TB cases showed that DR-MTB cases were significantly higher at age 15–34 years, pulmonary TB, and urban residents but with no significant difference regarding gender. The drugs resistance was significantly higher among the retreated cases compared with the new diagnostic patients (20.3% vs. 2.4%, p < 0.0001), with the percentage of the resistance to first-line drugs in primary and secondary cases including isoniazid (1% and 17.1%), rifampicin (0.78% and 15.8%), ethambutol (0.56% and 8.5%), streptomycin (1.3% and 9.75%). Notice that the most common drug resistance was against streptomycin with 1.3% in new patients and against isoniazid (17.1%) in retreated patients. The rate of total drug-resistant TB, multi-drug resistant TB, mono-drug resistant TB, and rifampicin-resistant TB among new tuberculosis cases increased in this period from 2.2 to 6.7%, 0.17 to 1.6%, 0.85 to 4%, and 0.17 to 4%, with a percentage change of 204.54, 841.17, 370.58, 22.5%, respectively. The rates of poly drug-resistant TB and ethambutol-resistant-TB dropped in this period by 15.96%, and 0.7%, with a decrease from 1.19 to 1% and from 1 to 0.3%, respectively. Similarly, the increase of drug-resistant TB among secondary cases has also occurred. In conclusion, the temporal trend showed an increase in the rate of drug resistance of M. tuberculosis since 2016, with a predominant multi-drug-resistant TB and isoniazid-resistant TB. Open in a separate window  相似文献   
8.
This research comprises studies on the transfer of cadmium (CdCl(2)) from the lactating dam to the pup via milk and absorbed in the suckling, showing that cadmium is transferred to the testes, ovary, cerebellum, and thyroid gland during development. The present studies were carried out in order to assess the protective effects of selenium against cadmium toxicity in pregnant rats. On the sixth day of gestation, the females were dosed subcutaneously either with cadmium or with cadmium and selenium in the following doses (mg/kg of body weight): 0, 1 Cd, 1 Cd?+?1 Se, 2 Cd, 2 Cd?+?2 Se. In groups treated with cadmium, no maternal or embryonic toxicities were observed; however, an increase in testes diameters of seminiferous tubules, a progressive sloughing of germ cells, vacuolization of Sertoli cells, and Leydig cells hyperplasia were noted. The reduction in the ovary size and inhibited folliculogenesis resulted in diminution of the numbers of primordial, growing, and tertiary follicles. The pathological change in the cerebellum, the migration of granular cells from the external germinal layer to the internal granular layer, was strongly retarded. Also, the formation of many microfollicles in the thyroid gland which mimic the changes was seen in thyrotoxicosis. It also appears that selenium used at a low-enough dose could be a very effective protection against cadmium-induced developmental toxicity in the testes, ovary, cerebellum, and thyroid gland but not in the higher dose in the ovary and cerebellum.  相似文献   
9.
Summary This investigation includes a study of the effect of ammonium salt, nitrate and urea as nitrogen sources; vitamin B6 as cofactor in transamination, and of acetate, pyruvate and glucose as carbon sources on the dry weight, total nitrogen and amino acid synthesis in Ulva, Dictyota and Pterocladia. The results showed that urea and to a lesser extent ammonium salt were better nitrogen sources for either Ulva or Pterocladia, while ammonium salt was best for Dictyota. Vitamin B6 was effective in transaminations and resynthesis of amino acids in the three marine algae, especially Ulva. Pyruvate was a better carbon source than either acetate or glucose in increasing dry weights, total nitrogen and amino acid synthesis in Ulva and Dictyota, whereas acetate was best in Pterocladia.  相似文献   
10.
Isoenzyme analysis and activities of peroxidase (PER), polyphenol oxidase (POD) and glutamate oxaloacetate (GOT) and randomly amplified polymorphic DNA (RAPD) fingerprints were used to analyze somaclonal variations in tissue culture-derived date palm plants. The frequency of somaclonal variations was found to be age dependent. Similar isoenzyme patterns for PER and GOT were detected in all analyzed plants. However, variations in activities of the three enzymes studied and in POD isoenzymes were detected. RAPD analysis showed genetic variations in approximately 4 % of the analyzed plants (70 regenerants). The genetic variations were only detected in 6- and 12-months-old cultures. It was observed also that all morphologically abnormal shoots showed genetic variations at the molecular level.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号