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1.
Four compounds, bis dimethylaminophosphonous anhydride ( anhydride ), bis (dimethylamino)fluorophosphine oxide ( oxide ), diethyl paranitrophenyl phosphate ( E 600) and sodium fluoroacetate ( acetate ), previously shown to have systemic insecticidal activity against aphids, have now been tested against the eggs and larvae of Pieris brassicae L.
The anhydride proved to have very little toxic action on Pieris , but the other three compounds showed both contact toxicity and systemic insecticidal action when taken up by the roots of cabbage plants from solution and from soil. The acetate, but more especially the E600, also showed systemic action following application to the leaves.
In all cases the order of decreasing toxicity was E600 > acetate > oxide > anhydride. E600 is the only compound which is outstandingly toxic to Pieris eggs and larvae. It has the added interest that when watered on to the roots of cabbage plants it kills larvae in egg batches on the leaves. Death takes place at the stage when the larvae are biting through the shells. The oxide and acetate proved to be surprisingly innocuous.
Unless it is felt to be too poisonous E600 is worthy of consideration as an insecticide against Pieris eggs and larvae, since it is highly effective as a contact insecticide and also has some systemic action.  相似文献   

2.
本文对电刺激家兔腹部的迷走神经外周端所引起的降压反应进行了研究。在121只家兔中的实验结果表明:电刺激腹部迷走神经外周端可引起动脉压、小肠和后肢的灌流压同时降低,而心率则无明显变化。这一降压反应发生时,小肠静脉血中的组织胺含量较刺激前明显升高,然后恢复;将小剂量的组织胺 H_1受体阻断剂扑尔敏、非乃根和 H_2受体阻断剂甲氰咪胍(Cimetidine)分别注入肠系膜上动脉均能减弱刺激腹部迷走神经外周端引起的动脉压和小肠灌流压的降低。心得安能削弱此降压反应,而阿托品无效;切断两侧内脏大神经能显著削弱刺激腹部迷走神经外周端引起的降压反应。此残余的降压反应在注入抗组织胺剂后完全消失。由此推论,刺激家兔腹部迷走神经外周端引起的降压反应是通过中枢和外周两方面因素的作用,使血管舒张,外周阻力降低而实现的。  相似文献   

3.
Local and systemic control mechanisms have been postulated to explain the maintenance of steady state cell renewal in intestinal epithelium. Permanent alterations of cell renewal resulting in a new steady state imply alterations in control. Intestinal resection appears to cause such alterations resulting in hyper-plasia of the residual intestine. To test the hypothesis of a systemic control, the effect of 60% mid-intestinal resection on Thiry-Vella fistulae of both jejunal and ileal origin was observed in rats. Results showed that hypoplasia occurred in fistulae without resection of the remaining intestine in continuity. Cell counts of crypt and villus columns and tritiated thymidine uptake in isolated whole crypts were reduced. Scanning electron microscopy showed marked hypoplastic alterations in villi. However, when 60% of the intestine in continuity was resected, hyperplasia occurred not only in the residual intestine but in the fistulae of both jejunal and ileal origin. Cell counts of villus and crypt columns were increased along with increased tritiated thymidine uptake per crypt. Neutral cc-glucosidase and non-specific esterase activities did not change as a result of resection but the activities of both enzymes were greater in ileal fistulae than in ileum in situ. Observations on the different resection response of the jejunal versus ileal fistulae lead to a distinction between inherent and induced differences within the small intestine. This study suggests a systemic control of cell renewal. A possible mechanism involving intestinal vascular physiology is discussed.  相似文献   

4.
The prophylactic effect resulting from the localized application of streptomycin as a foliage spray on dwarf bean plants has been examined. Streptomycin sulphate solution applied to the primary leaves exhibited a marked and consistent systemic, antibacterial, prophylactic action even at sites as far removed from the point of application as the fourth trifoliate leaf. This systemic protection against the halo blight organism persisted for various periods up to a maximum of 11 days. Mannosidostreptomycin was much inferior to streptomycin in its systemic prophylactic action against halo blight.  相似文献   

5.
Vertebrates are practically unique among the Metazoa in their possession of a skeleton made from calcium phosphate rather than calcium carbonate. Interpretation of the origin of a phosphatic skeleton in early vertebrates has previously centered primarily on systemic requirements for phosphate and/or calcium storage or excretion. These interpretations afford no anatomical or physiological advantage(s) that would not have been equally valuable to many invertebrates. We suggest the calcium phosphate skeleton is distinctly advantageous to vertebrates because of their relatively unusual and ancient pattern of activity metabolism: intense bursts of activity supported primarily by rapid intramuscular formation of lactic acid. Bursts of intense activity by vertebrates are followed by often protracted periods of marked systemic acidosis. This postactive acidosis apparently generates slight skeletal dissolution, associated with simultaneous vascular hypercalcemia. A variety of apparently unrelated histological features of the skeleton in a number of vertebrates may minimize this postactive hypercalcemia. We present new data that suggest that postactive skeletal dissolution would be significantly exacerbated if bone were composed of calcium carbonate rather than calcium phosphate. The former is far less stable both in vivo and in vitro than is calcium hydroxyapatite, under both resting and postactive physiological conditions.  相似文献   

6.
Our studies were conducted to examine the influence of extremely low frequency magnetic fields (ELF-MF) on skin wound healing in male adults rats. We used 40 Hz and 10 mT sinusoidal fields. We evaluated the rate of wound healing by determining the tissue hydroxyproline concentration and scar imaging in electron microscope. The systemic body response to ELF-MF was detected by analysis of blood morphological and biochemical parameters, such as: RBC, WBC, hemoglobin, hematocrit, reticulocytes, electrolytes, urea, and total protein concentration.

ELF-MF induced the increase of hydroxyproline level in scar tissue and intensified the maternity of collagen seen in the electron microscope. The increase of reticulocyte number in blood confirmed that the healing process in experimental animals was supported by the activation of the oxygen supply and utilization processes, as a result of erythropoietic intensification, without simultaneously upsetting cellular energetic processes. We did not obtain changes in biochemical parameters in blood, such as: electrolytes, urea, and total protein concentration, so we concluded that ELF-MF evoked no negative systemic response.  相似文献   

7.
The susceptibility of tomato plants to systemic infection by tomato spotted wilt virus was increased by increasing nitrogen supply to levels above that optimal for growth. The virus content, estimated by local-lesions counts, was also raised by increasing nitrogen. The period between inoculation and the appearance of systemic symptoms was decreased by increasing nitrogen to a point slightly greater than the optimal level for growth, but increased by additional applications.
Infected plants receiving more nitrate or ammonium compounds than were needed for optimal growth showed abnormal leaf symptoms and no bronzing. N, P and Mg analyses showed that these symptoms were related primarily to nitrogen content. Such leaves contained more virus than bronzed leaves.  相似文献   

8.
合浦珠母贝珍珠的生物学性能初步检测   总被引:2,自引:2,他引:0  
本研究报道了合浦珠母贝珍珠的生物学性能初步检测结果。珍珠作为—种天然的生物材料。在医药、化妆品工业等领域中的应用已很广泛。本研究对合浦珠母贝珍珠进行了体外细胞毒性试验、溶血试验和经静脉全身急性毒性试验的研究。实验结果表明,合浦珠母贝珍珠具有较好的细胞相容性,其浸提液对实验动物无明显毒性。在本研究中,合浦珠母贝珍珠的浸提液对兔血红细胞的溶血指数高于对照组。  相似文献   

9.
刺激大鼠外侧缰核对脊髓背角神经元伤害性反应的影响   总被引:1,自引:1,他引:0  
张一红  程珍凤 《生理学报》1994,46(4):320-326
电刺激大鼠一侧外侧缰核可对脊髓疹角广动力型神经元的伤害性放电产生明显抑制;这种抑制效应可部分地被静脉注射赛庚啶及酚妥拉明所阻断,电解损毁LHb对WDR神经元的放电无影响,本文结果表明,LHb参与了脊髓上结构对脊髓背角WDR神经元伤害性反应的下行抑制,这种下行抑制为位相性抑制。  相似文献   

10.
—Quantitative analyses performed on the lipids of cerebral grey matter from brains of a normal child and a child with Tay-Sachs (T-S) disease were compared with such analyses on the brain of a 6-year-old, non-Jewish male with systemic GM2-gangliosidosis of a late infantile type (GM2-LI). Analysis of gangliosides showed a 3·5-fold increase of total gangliosides in the GM2-LI brain and a six-fold increase in the T-S brain, compared to normal brain. Both pathological brains had similar distribution patterns for gangliosides, with the GM2-ganglioside component constituting more than 80 per cent of the total. Lipid components in the T-S brain were below normal values except for lecithin and cholesterol, while in the GM2-LI brain there were increases in sulphatides, cerebrosides, sphingomyelin and cholesterol. Approximately twice as much ceramide trihexoside was present in the T-S brain as in the GM2-LI brain, and none could be detected in the normal brain. The clinical, pathological and biochemical data support the conclusion that this case represents a new variant of systemic late-infantile gangliosidosis in which there is an accumulation of the GM2-ganglioside like that in Tay-Sachs disease.  相似文献   

11.
The reported low toxicity of schradan to honey-bees has been confirmed. This has led to the consideration of the possibility that this systemic insecticide might be present in nectar and subsequently appear in honey in an unchanged form.
Using radioactive schradan labelled with 32P, it has been shown that spray applications of this insecticide to mustard and borage plants result in the contamination of nectar. A series of nectar samples taken over a 4-week period following spraying showed on radio assay a progressive decrease in total 32P content and also in the amount of schradan present in proportion to the decomposition products. The highest figure recorded for the schradan content of nectar was 21 p.p.m.
Tests on the stability of schradan in contact with the honey stomach of the bee and also in contact with the enzyme invertase, in vitro , showed that no appreciable breakdown occurred. Furthermore it was shown that schradan was stable in contact with honey over a period of 2 1/2 months.
It is concluded that this systemic insecticide may appear in an unchanged form in the honey obtained from the nectar of plants which have been sprayed less than 4 weeks previously.  相似文献   

12.
利用电镜技术研究了内吸杀菌剂甲霜灵对向日葵霜霉菌在寄主向日葵上发育的影响。观察发现甲霜灵引起病菌发生一系列的变化。病菌胞间菌丝细胞内液泡、电子致密体增加,线粒体肿胀畸形;菌丝细胞壁不规则地加厚,部分极度加厚的细胞壁构成了假隔膜,并且在菌丝上还有不规则的突起形成。病菌吸器外间质明显不规则地变宽,其中充满大量电子致密度高的物质:部分吸器体不能正常扩张膨大,发育受阻而成畸形。向日葵霜霉菌的以上变化导致菌丝细胞和吸器的坏死,从而抑制了病菌的进一步发育。  相似文献   

13.
Nicotine and nicotine salts are taken up by the roots of plants from solutions, and when 0.01–0.001 % nicotine is used the plants become toxic to Aphis fabae and to Pieris brassicae larvae and can be shown to contain nicotine. The results with Phaedon cochleariae adults and larvae are less satisfactory. No systemic action is observed when the nicotine is watered on to soil in which plants are growing and no nicotine can be detected in the plants. Apparently the nicotine is decomposed in the soil.
When applied several times to the upper surface of a bean leaf nicotine kills aphids on the underside. There is some evidence that nicotine can be translocated further through the plant following leaf applications, but the toxic action at any distance is very weak in the plants used in the present experiments and can only be produced by frequent applications of rather concentrated nicotine solutions. Leaf absorption and subsequent translocation has not been observed with nicotine salts.
The various organic bases, including some piperidine phosphonites and allied compounds tested, are of very little interest as contact or systemic insecticides against aphids.  相似文献   

14.
When renal failure complicates postoperative recovery in any operative procedure, the mortality is expected to double. To avoid this complication, a technique was devised to preserve renal perfusion during resection of a thoracoabdominal aneurysm. With systemic heparinization, an extravascular shunt is placed between the descending aorta and the visceral branches; any blood loss is recovered by autotransfusion. After completion of the operation and reversal of heparinization, the normal clotting mechanism is restored by terminal reinfusion of 2 units of autogenous blood that had been collected and stored before heparinization.  相似文献   

15.
 近百年的禾草内生真菌研究历经了由浅入深的过程,从最初的家畜中毒事件认识到是一种共生内生真菌存在的缘故,到如今利用分子生物学技术揭示其共生机制,人类发现这类植物内生真菌并非想象中的对生态系统无足轻重。Epichloë及其无性型Neotyphodium与禾本科植物是系统发生的互利共生关系,尤其是Neotyphodium可提高宿主抵抗环境胁迫的能力和抵御动物的取食,增强植物的竞争力。禾草内生真菌有3种生活史:有性生活史、无性生活史和兼性生活史,后者表明真菌在不同的宿主及环境下既能营有性生殖也可营无性繁殖,是一种更灵活而有效的生活史对策。对内生真菌分子系统学、生活史以及与宿主禾草协同进化的研究发现,Neotyphodium起源于禾草致病真菌Epichloë的某些种,或是Epichloë与Neotyphodium的种间杂交后代。植物和内生真菌各异的生活史策略,真菌的种间杂交,两者的协同进化亦或种群间基因流的差异,都促成了共生体多样化的基因组合(Genetic combination ),也是其共生关系多样化的根源。内生真菌对宿主的有益作用只在特定基因型真菌、宿主和一定环境条件下才起作用,自然生态系统的共生关系要比农业系统复杂得多,是一个从互利共生至寄生关系的连续系统。未来对于更多共生体的遗传背景和基因与环境相互作用的阐明将有助于对禾草内生真菌共生关系本质更加深入的认识。  相似文献   

16.
THE INFECTION OF PLANTS BY VIRUSES THROUGH ROOTS   总被引:1,自引:0,他引:1  
Roots of young tomato plants became infected when inoculated with tomato bushy stunt, tobacco mosaic, and potato X viruses. Root infections also occurred when these viruses were added to soil or culture solutions in which plants were growing.
The viruses were sometimes localized around their initial entry points in roots; sometimes they invaded the root system but not the shoots, and sometimes they produced full systemic infection of roots and shoots. In some experiments, but not all, systemic infections were more frequent when the upper tap root or superficial roots were inoculated than when fibrous roots were inoculated.
In both tomato and potato, virus X spread from diseased to healthy plants sharing the same culture solution, if their roots were in contact, but not otherwise. Infection of the roots of potato plants by inoculation, produced only one plant with virus-infected haulms, although several had infected tubers.  相似文献   

17.
双歧杆菌生态制品对海人酸模型抗癫痫作用的初步观察   总被引:3,自引:0,他引:3  
用海人峻(KainicAcid,KA)10mg/kg给SDk鼠皮下注射,注射后0-1/2h之内,动物出现凝视和湿狗样抖动;1/2-2h,动物出现癫痫发作(严重程度从1级发展至5级);2h后,动物反复自发出现严重的癫痫发作;4h减弱;8h停止。实验组动物分别于1或3周前开始并连续从饮水中定量投喂双歧杆菌活菌制剂(0.5g/天/只)。结果表明,预先投喂该生态制品持续达3周组大鼠其癫痫发作受到明显抑制与对照组比较P<0.01。  相似文献   

18.
A method is described for assessing the systemic activity of compounds in checking the infection of broad bean ( Vicia faba ) by the fungi Botrytis cinerea or B. fabae. Treatment consisted in allowing the roots of young seedlings to stand in a solution containing 10 p.p.m. of the chemical for 2–3 weeks. The plants, together with controls, were then inoculated and when symptoms had had time to develop, the degree of chocolate spot infection was assessed. Several methods of disease assessment were examined and are critically discussed.
Certain phenoxyalkylcarboxylic acids tested by this method consistently gave a reduction in the mean size of fungus lesions on the bean leaves, clearly indicating systemic fungicidal action. The most promising substances were 2:4:6-trichlorophenoxyacetic, pentachlorophenoxyacetic and pentachlorophenoxy iso butyric acids. Further experiments with these compounds involving soil treatment, stem injection and spray application are described, and in most cases systemic fungicidal activity was clearly demonstrated. Certain compounds caused visible damage to the plants or resulted in a reduction in growth.
The results presented indicate that phenoxy acids can be fairly readily translocated in bean plants and that they tend to accumulate in actively growing tissues. It is considered unlikely, however, that they persist for long periods in plant tissue.
In the soil, the compounds appeared to remain effective for a considerable time, particularly the less soluble pentachloro acids, suggesting that soil application might provide a safe and useful method of treatment.  相似文献   

19.
观察了吸入0.004%的一氧化氮(NO)对急、慢性缺氧大鼠血流动力学、缺氧性肺血管收缩反应(HPV)、血气及高铁血红蛋白(MetHb)的影响。结果表明:(1)常氧吸入NO时能明显降低慢性缺氧大鼠肺动脉平均压(Ppa)和肺血管阻力(PVR),但对正常大鼠的Ppa和PVR无明显影响;(2)慢性缺氧大鼠急性缺氧时HPV较正常大鼠弱,吸入NO不但降低两者的急性缺氧肺动脉高压,且完全逆转两者的HPV;(3)吸入NO对急、慢性缺氧大鼠体循环血流动力学、血气及MetHb含量无明显影响。提示吸入NO能选择性降低急、慢性缺氧性肺动脉高压,且逆转HPV。  相似文献   

20.
The average branchial blood pressure in sand sharks was 32 mm. of mercury. The highest recorded in a resting animal was 43 mm. The average dorsal or systemic pressure was 23.3 mm.; highest 30 mm. The ratio of branchial to systemic pressure is about 3 to 2. The pressure in both systems keeps up well under trauma; but under experimental conditions, with or without manipulation of viscera, slowly falls after several hours. It rises with muscular effort, and a long rise usually follows stoppage of struggling. It rises when sodium carbonate is injected. The adrenalin curve resembles that in a mammal. Spontaneous rises and falls not attributable to the heart occur. Light in some animals increases blood pressure. It is suspected that these fishes have a vasomotor apparatus. The heart rate except after trauma is practically always the same as the respiration rate, and there is some reason for believing that the heart rate is determined by the respiration rate. When not in step with respiration, the heart is slower and often in a simple ratio with respiration. The heart is inhibited by all sorts of stimuli applied practically anywhere (except to the liver?). This effect is abolished by atropin. Respiration is faster in small animals and averages 24 per minute. Respiration slowly decreases in strength with little change in rate. Usually respiration ceases long before the heart stops.  相似文献   

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