首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Castrated androgen-insensitive rats exhibited mounting and intromission patterns in response to testosterone propionate (TP), estradiol benzoate (EB), or EB combined with dihydrotestosterone (DHT) treatment in adulthood. Treatment with DHT alone was ineffective in stimulating male mating behavior in the mutant rats. Since androgen-insensitive rats, like normal males, have the potential to show mounting behavior following hormone treatment in adulthood, the neural substrate underlying this behavior must be masculinized during development. The effectiveness of gonadal hormones in activating the entire copulatory sequence in castrated littermate males (King-Holtzman) was also examined. TP treatment induced mating behavior in the control rats. DHT also stimulated the complete copulatory pattern, although it was not as effective as TP. The administration of EB, however, did not induce ejaculation in control rats. These results do not support the hypothesis that the activation of male mating behavior by testosterone requires its metabolite estrogen (aromatization hypothesis).  相似文献   

2.
‘Giant race’ stem nematode (Ditylenchus dipsaci) was well controlled in spring beans (Vicia faba) by up to 5 kg aldicarb or carbofuran ha-1 applied to the seed furrows at sowing. Carbofuran was rather more effective in the clay loam soil used than was aldicarb. The best treatments almost eliminated injury to the stems and nematode infestation in the harvested seed. Similarly applied, oxamyl and fenamiphos were less effective and phorate, dimethoate and disulfoton were ineffective. Applying part of the dosage of an effective nematicide to the seed furrows and part along the plant rows mid-season was no more effective and was sometimes less effective than applying the whole dose to the seed furrows. Treating the plant rows mid-season with aldicarb or phoxim sometimes enhanced control but thiabendazole applied thus did not. Seed furrow applications of aldicarb or carbofuran were much less effective in controlling the nematodes in winter beans and seed dressings were less effective than seed furrow treatments. In one experiment, in plots in which aldicarb or oxamyl had been applied to the seed furrows, phoxim or thiabendazole applied over the rows of plants, enhanced nematode control. In two other experiments, thiabendazole was ineffective when applied in this way or when applied as a combined soil and plant treatment.  相似文献   

3.
A. sobria was isolated unexpectedly on Campylobacter selective medium from abortion specimens of 16 buffaloes. All strains (AS1-AS16) required Campylobacter growth supplement (sodium pyruvate, sodium metabisulphate and ferrous sulphate) and 10% C02 atmosphere on primary isolation. They were unusually sensitive to bile salt and failed to grow on MacConkey's agar. Biochemically, these strains were homogeneous but antibiogram profile and physiological/other characters revealed a moderate heterogeneity. In vitro antibiotic sensitivity pattern showed a number of antibiotics effective whereas only a few (penicillin and co-trimoxazole) ineffective against these strains. It took 9 days for 3 x 10(8) A. sobria organisms/ml in 5 ml quantity to terminate the pregnancy in an experimentally infected buffalo via iv route. Foetal and placental lesions were classical as that of field cases. The infection evoked serum antibody response. Apparently disease-free buffalo sera were devoid of such antibodies.  相似文献   

4.
1. Cobalt, copper, zinc and cadmium injected into Carassius auratus in April (water temperature 16°C) increased liver ornithine decarboxylase and adenosylmethionine decarboxylase and not tyrosine aminotransferase activities independently of their accumulation within the liver.2. As previously shown, cadmium stimulated ornithine decarboxylase in November (16°C), but was ineffective in July (23°C).3. Acclimation of fish at 23°C in April and November caused the metal to become ineffective, but acclimation at 15°C in July failed to restore the response to cadmium.4. In February no significant changes occurred either at 14°C or at 23°C with any of the metals.5. Putrescine and polyamine concentrations essentially followed the response of ornithine decarboxylase activity.  相似文献   

5.
The radiosensitizing potential in hypoxic EMT6 cells of several complexes of Co(III) and Fe(III) has been examined. The cytotoxicity of each of the agents toward oxygenated and hypoxic EMT6 cells was tested over the concentration range of 1 to 500 micron for 1-h drug exposure. There was no statistically significant difference between the cytotoxicity of these complexes toward oxygenated and hypoxic cells. Based on these findings, 100 micron was selected as the drug concentration for the initial assessment of radiosensitizing potential. The radiation survival of EMT6 cells in the presence of 100 microM drug for a series of Co(III) complexes in which the number of nitro ligands was varied showed that the hexanitro and the triamine-trinitro complexes are very effective radiosensitizers. The trans-tetrammine dinitro complex was a more effective radiosensitizer than the corresponding cis-dinitro complex. The diethylenetriamine and 1,10-phenanthroline complexes were very effective radiosensitizers, producing dose-modifying factors of 2.4. The trans-tetrammine dichloro complex was moderately effective, giving a dose-modifying factor of 1.9. On the other hand, the hexammine and triammine tricyano complexes and the trans-dinitro complex with negatively charged acetylacetonate ligands were ineffective as radiosensitizers in this system. Finally, three complexes with cyclopentadienyl ligands were examined. The ferricenium salt itself was a moderately effective radiosensitizer, giving a dose-modifying factor of 2.0. However, both the dimethylferricenium salt and the analogous cobalt complex were ineffective. The FSaIIC fibrosarcoma was used to study radiosensitizing potential in vivo. The trans-tetramminedinitro complex was administered at doses of 100, 200, or 300 mg/kg as a single ip injection 1 h prior to irradiation or as three daily ip injections. There was increasing dose modification with increasing drug dosage. With a fractionated radiation protocol in which five daily fractions of 2, 3, or 4 Gy were administered to the tumor-bearing limb with ip drug injections of 100 or 200 mg/kg given 1 h prior to irradiation, a dose-modifying effect of 1.6 was observed with 5 X 200 mg/kg of the drug.  相似文献   

6.
The potent tumor promoter 12-O-tetradecanoylphorbol 13-acetate causes a 2-fold increase in 1,2-diacylglycerol levels within 15–30 min in cultured chick embryo differentiated myoblasts. The weak tumor promoter 12-O-decanoylphorbol 13-acetate was 250 times less effective and the non-promoter 4-α-phorbol 12,13 didecanoate was ineffective at producing this response. During subcellular fractionation, the stimulated portion of the diacylglycerol was distributed similarly to the plasma membrane fraction. Evidence is presented that this diacylglycerol originates from pre-existing lipid rather than from denovo synthesis. Possible implications of these findings with regard to the inhibition of myoblast fusion by the tumor promoter are discussed.  相似文献   

7.
The competitive ability of effective and ineffective isolates of Bradyrhizobium to form nodules on four peanut (Arachis hypogaea) genotypes from which they were originally isolated was investigated in a greenhouse study. Pregerminated seeds of each genotype were inoculated with five ratios of ineffective effective bradyrhizobia: 104:0, 104:102 104:104 102:104 and 0:104. Plants were harvested 35 days after planting and nitrogenase activity, total nodule number per plant, plant shoot dry weight and the proportion of nodules formed by each Bradyrhizobium isolate were determined. Nodulation suppression occurred on plants inoculated with the mixed cultures, especially on those inoculated with the 104:102 ineffective effective inoculum ratio. More than 85% of the nodules on plants inoculated with the 104:104 and 102:104 ineffective effective Bradyrhizobium mixtures were formed by the effective isolates. The number of effective nodules per plant, nitrogenase activity and plant shoot dry matter production all increased with the proportion of the effective bradyrhizobia in the inocula.  相似文献   

8.
摘要 目的:研究血浆循环游离DNA(cf DNA)联合癌胚抗原(CEA)在评估晚期非小细胞肺癌(NSCLC)治疗疗效中的临床价值。方法:选取我院2019年1月~2022年1月收治的96例晚期NSCLC患者作为研究对象,所有患者均接受含铂双药化疗方案或放疗,评估治疗6个月后的临床疗效,根据疗效分为有效组与无效组,检测所有患者cf DNA及CEA水平并进行比较,单因素、多因素分析患者疗效的影响因素,并通过受试者工作特征曲线图(ROC)分析cf DNA及CEA对晚期NSCLC患者治疗疗效的评估价值。结果:本研究中96例患者均顺利完成化疗治疗,疗程结束后,有54例(56.25%)治疗有效,42例(43.75%)治疗无效;无效组肿瘤TNM分期Ⅳ期、体力状况(PS)评分2~4分占比大于有效组(P<0.05);无效组患者cf DNA及CEA水平明显高于有效组(P<0.05);多因素Logistic回归分析显示,肿瘤分期Ⅳ期、PS评分2~4分、cf DNA及CEA高水平均为影响晚期NSCLC患者疗效的相关因素(P<0.05);ROC曲线分析显示,cf DNA、CEA对晚期NSCLC患者治疗后无效均有预测效能(P<0.05),其中两指标联合预测的曲线下面积(AUC)最大,为0.794,特异度、敏感度分别为85.19%、78.57%。结论:治疗无效晚期非小细胞肺癌患者cf DNA及CEA水平更高,肿瘤分期Ⅳ期、PS评分2~4分、cf DNA及CEA高水平均为晚期NSCLC患者疗效的影响因素,联合cf DNA及CEA检测有利于对晚期NSCLC患者治疗疗效进行评估。  相似文献   

9.
Competition between effective and ineffective Rhizobium galegae strains nodulating Galega orientalis was examined on the basis of plant growth, nodulation, antibiotic resistance, and PCR results. In a preliminary experiment in Leonard's jars, ineffective R. galegae strains HAMBI 1207 and HAMBI 1209 competed in similar manners with the effective strain R. galegae HAMBI 1174. In a pot experiment, soil was inoculated with 0 to 10(5) HAMBI 1207 cells per g before G. orientalis was sown. Seeds of G. orientalis were surface inoculated with 2 x 10(4) and 2 x 10(5) cells of HAMBI 1174 per seed (which represent half and fivefold the commercially recommended amount of inoculant, respectively). Plant yield and nodulation by the effective strain were significantly reduced, with as few as 10(2) ineffective rhizobia per g of soil, and the inoculation response was not improved by the 10-fold greater dose of the inoculant. Bacteria occupying the nodules were identified by antibiotic resistance and PCR with primers specific for R. galegae HAMBI 1174, R. galegae, and genes coding for bacterial 16S rRNA (bacterial 16S rDNA). Sixty-two large nodules examined were occupied by the effective strain HAMBI 1174, as proven by antibiotic resistance and amplification of the strain-specific fragment. From 20 small nodules, only the species-specific fragment could be amplified, and isolated bacteria had the same antibiotic resistance and 16S PCR restriction pattern as strain HAMBI 1207. PCR with our strain-specific and species-specific primers provides a powerful tool for strain identification of R. galegae directly from nodules without genetic modification of the bacteria.  相似文献   

10.
Standard PCR was ineffective in detecting a baculovirus-derived chitinase transgene in the T1 generation of chitinase-expressingNicotiana tabacum cv. CF80 after leaves were flue-cured at high temperatures. Consequently, a seminested PCR method was developed using fresh leaves from T2 generation plants also expressing the chitinase protein. Seminested PCR was highly effective in detecting the chitinase transgene in fresh leaves ofN. tabacum cvs. Xanthi-nc and K326 and in both fresh and flue-cured leaves ofN. tabacum cv. CF80.  相似文献   

11.
Small-plot (approximately 0.1 ha) studies were used to evaluate different pheromone dispensing systems, application rates, and point-source densities for mating disruption of the tufted apple bud moth, Platynota idaeusalis (Walker). Using polyvinyl chloride spirals impregnated with tufted apple bud moth pheromone (1:1 ratio of E11-tetradecenyl alcohol/E11-tetradecenyl acetate), pheromone rates of > or = 1,482 spirals per hectare (74.1 g pheromone per hectare) were superior to a rate of 988 spirals per hectare (49.4 g pheromone per hectare) in decreasing male response to pheromone traps in 1995, whereas no differences were detected among rates of 988, 1,482 and 1,975 spirals per hectare in 1996. Within a range of 370-988 pheromone dispensers per hectare, point source densities were equally effective in suppressing male response to pheromone traps. Pheromone-impregnated paraffin disks were equally effective at inhibiting male response to pheromone traps compared with polyvinyl chloride spirals. However, a paraffin emulsion formulation of pheromone applied with a hand-held grease gun provided longer residual communication disruption effects than polyvinyl chloride spirals. Dilution of paraffin emulsion pheromone formulations in water for application with a backpack sprayer and airblast sprayer rendered them ineffective in reducing male response to pheromone traps. The releases of pheromone from polyvinyl chloride spirals and paraffin disks aged in the field were described by a linear and negative logarithmic curve, respectively, indicating that dispenser life time should be longer for spirals. The ratio of acetate to alcohol components of pheromone released from spirals increased over time, whereas the release ratio remained more constant for paraffin disks. This suggests that the disruption efficacy of spirals may be prematurely reduced because of imbalance of the released components.  相似文献   

12.
Chinese hamster V79 cells were exposed to high LET (linear energy transfer) (16)O-beam (625keV/mum) radiation in the dose range of 0-9.83Gy. Cell survival, micronuclei (MN), chromosomal aberrations (CA) and induction of apoptosis were studied as a follow up of our earlier study on high LET radiations ((7)Li-beam of 60keV/mum and (12)C-beam of 295keV/mum) as well as (60)Co gamma-rays. Dose dependent decline in surviving fraction was noticed along with the increase of MN frequency, CA frequency as well as percentage of apoptosis as detected by nuclear fragmentation assay. The relative intensity of DNA ladder, which is a useful marker for the determination of the extent of apoptosis induction, was also increased in a dose dependent manner. Additionally, expression of tyrosine kinase lck-1 gene, which plays an important role in response to ionizing radiation induced apoptosis, was increased with the increase of radiation doses and also with incubation time. The present study showed that all the high LET radiations were generally more effective in cell killing and inflicting other cytogenetic damages than that of low LET gamma-rays. The dose response curves revealed that (7)Li-beam was most effective in cell killing as well as inducing other nuclear damages followed by (12)C, (16)O and (60)Co gamma-rays, in that order. The result of this study may have some application in biological dosimetry for assessment of genotoxicity in heavy ion exposed subjects and in determining suitable doses for radiotherapy in cancer patients where various species of heavy ions are now being generally used.  相似文献   

13.
14.
Endothelins (ETs) are vasoactive peptides evolutionary well conserved that exert their effects through two specific receptors (ET(A) and ET(B)) widely distributed in all vertebrates. In snakes, the presence and function of endothelins and their receptors are still scarcely described. We have recently demonstrated the presence of ET(A) and ET(B2) receptors in the snake Bothrops jararaca (Bj). In the present work we showed that distinctively from Bj, the vascular contraction induced by endothelin in Oxyrhopus guibei (Og) snake is mediated only by ET(A) receptors. Selective ET(B) agonists (SRTX-c and IRL(1620)) and antagonists (IRL(1038) and BQ(788)) were ineffective in Og preparations of isolated aorta. We also showed that ET-1 response on Og arterial blood pressure was monophasic hypertensive as opposed to biphasic (hypotension followed by hypertension) in Bj. Furthermore, we characterized the relaxing properties of endothelin receptor ET(B1) in pre-contracted aorta preparations. We showed that IRL(1620) induced relaxation of pre-contracted Bj aorta but was ineffective in relaxing Og preparations. IRL(1620) relaxing effect on Bj aorta was abolished by l-NAME, indicating involvement of NO release, and was reduced by selective ET(B) antagonists. Our findings suggest that Og snake has a more primitive spectrum of ET receptors (only ET(A) receptor) than Bj (presence of ET(A), ET(B1) and ET(B2) receptors).  相似文献   

15.
We evaluated the efficacy of the systemic insecticides dinotefuran, emamectin benzoate, fipronil, and imidacloprid for preventing attacks and brood production of southern pine engraver beetles (Coleoptera: Curculionidae: Scolytinae) and wood borers (Coleoptera: Cerambycidae) on standing, stressed trees and bolt sections of loblolly pine, Pinus taeda L., in eastern Texas. Emamectin benzoate significantly reduced the colonization success of engraver beetles and associated wood borers in both stressed trees and pine bolt sections. Fipronil was nearly as effective as emamectin benzoate in reducing insect colonization of bolts 3 and 5 mo after injection but only moderately effective 1 mo after injection. Fipronil also significantly reduced bark beetle-caused mortality of stressed trees. Imidacloprid and dinotefuran were ineffective in preventing bark beetle and wood borer colonization of bolts or standing, stressed trees. The injected formulation of emamectin benzoate was found to cause long vertical lesions in the sapwood-phloem interface at each injection point.  相似文献   

16.
Summary The relative nitrogen fixation efficiencies (RE 1-[H2 evolved÷C2H2 reduced]·100) of four mesquite (Prosopis glandulosa var.torreyana) rhizobia (Strains WR 1001, WR 1002, L5, L9) and a cowpea rhizobia (Strain 176A32) on mesquite were evaluated in a glasshouse experiment. Plant yield, shoot N accumulation, and the natural15N abundance (15N) of nodule tissue were determined. Strain WR 1002 failed to nodulate mesquite and strain L5 produced ineffective nodules. Among the three effective strains (WR 1001, L9, 176A32) the cowpea strain (176A32) and strain L9 had significantly higher RE than strain WR 1001. Differences in RE, however, were not accompanied by significantly higher plant yield and shoot N accumulation. The difference in15N abundance between foliar tissue and nodules (nodules minus leaves) was 0.47 15N for the ineffective L5 nodules, while for the effective WR 1001, L9, and 176A32 nodules, respectively, this difference was 8.35, 7.81, and 8.35 15N. This indicates a similar relationship between N2-fixing effectiveness and natural15N enrichment of nodules that was previously observed in soybeans (Glycine max, L. Merr.). Strains WR 1001 and L9 produced elongate, indeterminate nodules typical for mesquite. The ineffective L5 nodules had few infected cells and an abundance of cortical amyloplasts. Mesquite nodules produced by the cowpea strain were spherical and were somewhat more similar in internal morphology to determinate nodules typical of cowpea than indeterminate nodules normally associated with mesquite.  相似文献   

17.
A betamimetic and tocolytic compound (Planipart(R) = 4-amino-alpha-[(tert.-butyl-amino)-methyl] 3-5-dichlor-benzylalcohol-hydrochloride; Boehringer Ingelheim, Vetmedica GmbH) was used to effectively interrupt or postpone parturition in 39 cows and heifers, 13 pigs and three sheep. Its fast action, long duration, and freedom of clinical side effects were confirmed in clinical and tocographical in-vivo studies. Parturition was interrupted during stage I and early stage II of labor. With declining effects of Planipart(R), oxytocin can initiate renewed labor. Oxytocin is ineffective if the myometrium is under full control of Planipart, while Planipart(R) is ineffective when oxytocin (endogenous or exogenous) exerts its control on the myometrium. Deliveries after postponement or interruption seem subjectively to proceed faster and easier. No deleterious effects on mother or offsprings were observed in the postpartum phase or during lactation. Planipart may be used effectively in obstetrics and for biotechnical purposes.  相似文献   

18.
In Acrochaetium asparagopsis (Chemin) Papenfuss, tetrasporocyst formation is a genuine short-day photoperiodic response. Experiments in bi-diurnal and tri-diurnal cycles have shown that maximum inhibition of the response occurred with night-breaks given at approximately 24 h intervals and coincided with the postulated skotophile phase, while maximum stimulation was due to night-breaks in the postulated photophile phase. In cycle length experiments the fertility was stimulated in cycle lengths of 24 and 44 h and it was inhibited in cycle lengths of 36–40 and 52 h (or more). In addition the response was inhibited by light periods longer than 14 h, however long the associated dark period. Dark periods of various durations were completely ineffective in initiating tetrasporocysts and an induction phase of 5–7 short-days (8:) was necessary for the fertility. The lighting treatment following the induction phase was found to have no significant effect on the fertility and tetrasporocysts were obtained in continuous light or darkness. In resetting experiments, three more reversed short-day cycles (11 cycles, :8, photoperiod started at 24.00) were required to obtain the same maximum fertility (100%) observed under normal short-day cycles (9 cycles, 8:16, photoperiod started at 08.00). The induction, however, was completely lost with 96 h of continuous light (20 µE m-2s-1) and even 14 reversed short-day cycles were ineffective in initiating a new rhythmic mechanism.  相似文献   

19.
Soil-based growth cabinet and greenhouse experiments were designed to determine whether a resistance response previously noted in Trifolium repens to the clover cyst nematode Heterodera trifolii was systemic and also effective against a pest from a different taxon. Root applications of benzo(1,2,3)thiadiazole-7-carbothioic acid-S-methyl ester (BTH) or a Pseudomonas -like bacterial strain P29 to white clover seedlings induced resistance to the blue-green aphid, Acyrthosiphon kondoi . A similar response was observed in the annual medic, Medicago truncatula var truncatula . Estimation of lignin and callose content of whole plants at the termination of the bioassay showed no differences between treated and control plants. The significance of these findings is discussed.  相似文献   

20.
Mutants isolated from effective R. meliloti strain L5-30 which required histidine (his-240), arginine+uracil (arg-55) and cysteine (cys-243, cys-244 and cys-246) showed also loss of effectiveness. Mutant requiring isoleucine+valine (ilv-74) was non-infective. Relation of the metabolic deficiency to the symbiotic properties of these mutants was tested comparing symbiotic response of their prototrophic revertants and transductants. It was found that all revertants and transductants of the strain his-240 were effective which suggests that histidine deficiency was the cause of their ineffectiveness. All revertants and transductants of the cysteine mutants were still ineffective. This result indicates two independent mutations which were not cotransductible. Prototrophic revertants of the mutant arg-55 were ineffective whereas 56.9 percent of transductants appeared effective suggesting close linkage of two mutations. i.e. auxotrophic and the other concerned with symbiotic effectiveness. Though one of 69 prototrophic transductants obtained from the non-nodulating mutant ilv-74 remained non-nodulating, it seems that changes in nodulating ability of the mutant are related to the auxotrophic requirements.  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