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1.
Acute phase protein precipitating sonatic C-polysaccharide of pneumococci appears in serum of women under treatment with hormonal contraceptives in a significantly higher number of cases when compared with control groups. The summarized results of three preliminary studies show that in 80 control serums there were four positive specimens (5 percent) and in 80 serums from women using hormonal contraceptives there were 58 positive specimens (72.5 percent).  相似文献   

2.
Plants live in fixed locations and survive adversity by integrating growth responses to diverse environmental signals. Here, we show that the nuclear-localized growth-repressing DELLA proteins of Arabidopsis integrate responses to independent hormonal and environmental signals of adverse conditions. The growth restraint conferred by DELLA proteins is beneficial and promotes survival. We propose that DELLAs permit flexible and appropriate modulation of plant growth in response to changes in natural environments.  相似文献   

3.
在正常生理条件下,分别以抗草甘膦转基因大豆饲料和非转基因大豆饲料喂食雄性昆明小鼠,至30 d检测其运动能力、耐疲劳能力和耐缺氧能力,探讨抗草甘膦转基因大豆对雄鼠运动机能的影响。同时以环磷酰胺处理建立小鼠病理模型,探讨病理条件下抗草甘膦转基因大豆对雄鼠运动能力、耐疲劳能力和耐缺氧能力的作用。结果显示,在正常生理条件下,与非转基因对照组相比,喂食30 d抗草甘膦转基因大豆饲料组雄鼠的运动能力、耐疲劳能力和耐缺氧能力均无统计学差异(P>0.05);同样,在环磷酰胺诱导的病理条件下,喂食抗草甘膦转基因大豆饲料30 d也不会对雄鼠运动能力、耐疲劳能力和耐缺氧能力造成不良影响。结果表明,喂食抗草甘膦转基因大豆饲料30 d对雄鼠运动机能无毒性效应。  相似文献   

4.
为了检测NAS中草药复合制剂的毒性,对其药物安全性做出客观评价,进行了大鼠亚急性毒性试验.设高、中、低3个药剂量组和一个空白对照组,每天以金属胃管经口给Wistat大鼠灌服1次NAS中草药复合制剂,连续14 d,空白组大鼠自由采食饮水.通过对大鼠行为、饮水、精神状态、食欲状况、剖检后各试验大鼠组织器官和组织学变化的观察以及对其体质量变化、血液生理生化指标的测定,表明NAS中草药复合制剂对大鼠的各项生理活动、血液生理生化指标、主要组织器官均无不良影响.试验过程中,各给药剂量组大鼠未出现中毒反应,无死亡现象,据此认为NAS中草药复合制剂对实验动物大鼠安全无毒副作用.  相似文献   

5.
The failure of even special methods to induce infection indicates that not all strains of young white laboratory mice (Mus musculus) are uniformly susceptible to fatal infection with Leptospira icterohemorrhagiae. Some strains of this species develop early pathological changes characteristic of the infection and harbor the organism in their kidneys, but do not succumb. Therefore not all strains of white mice are suitable for use in the diagnostic mouse protection test for leptospirosis described by Larson.  相似文献   

6.
腹腔镜技术在山羊胚胎移植中的应用   总被引:11,自引:0,他引:11  
本文详细介绍了山羊在站立保定下进行腹腔镜检查的方法,对检查中所观察到的生殖器官的生理及病理现象进行了较系统的描述。研究表明,超排处理山羊卵巢反应异常者占53.2%;自然发情及诱导发情羊异常发情者占32.4%。作者认为,在奶山羊胚胎移植工作中应用腹腔镜技术,可减少盲目性手术及无效工作量,并提高手术成功率。  相似文献   

7.
张云凤 《北京农业》2012,(9):143-144
人类生存环境的异常变化都会不同程度地影响人体的正常生理功能。人类具有调节自己的生理功能来适应环境的变化的能力,但人体的适应能力是有一定限度的。如果环境的异常变化超出人体正常生理调节的限度,则可能引起人体某些功能和结构发生异常并造成病理性的变化。汞是危害人体健康极大的重金属,并且由于其特殊的物理化学性质和毒性,己成为污染环境的主要污染物之一。现结合多方面因素,对汞的性状、污染来源及其对人的危害,以及如何采取科学有效的防治措施和加强行业教育提出了自己的建议。  相似文献   

8.
Identification of triploid genome by fluorescence microscopy   总被引:3,自引:0,他引:3  
Fluorescence markers on chromosome numbers 3, 13, and 14 gave cytological evidence of the paternal origin of the extra haploid set in a premature triploid infant with XXY sex chromosome complement. The mother had discontinued the use of oral contraceptives 13 months prior to conception. It is not possible to tell whether the mechanism involved was fertilization by dispermy or by a diploid sperm.  相似文献   

9.
植物液泡膜 ATP 酶(H+-ATPase)和液泡膜焦磷酸酶(H+-PPase)是液泡膜上两个含量丰富的蛋白,其功能的正常发挥在植物生长发育过程中扮演着重要角色。液泡膜 H+-ATPase 和 H+-PPase 水解底物释放能量,同时产生大量 H+由胞质泵入液泡内,形成细胞质与液泡间的 H+ 电化学势梯度,为多种溶质分子的跨膜主动运输提供驱动力,维持细胞内的离子稳态和渗透平衡,为细胞内各种生理生化反应的正常运行提供保障。此外,液泡作为植物细胞离子养分的储存库,其膜上 H+-ATPase 和 H+-PPase 能够通过改变其活性来调控硝酸盐在胞质和液泡间的分配比例,进而影响植物的氮素利用效率。在逆境胁迫条件下,提高液泡膜 H+-ATPase 和 H+-PPase 的活性有利于提高植株对逆境的适应能力,从而减少逆境胁迫对植株生长发育造成的不利影响。介绍了植物液泡膜 H+-ATPase 和 H+-PPase 的结构特征及其在植物生长发育过程中的生理功能,并对其在植物抵御非生物逆境胁迫过程中发挥的重要作用进行阐述,为进一步提高作物的氮素利用率及逆境适应能力提供方向。  相似文献   

10.
Applications of Trichoderma formulations in crop protection   总被引:1,自引:0,他引:1       下载免费PDF全文
The choice of active Trichoderma strains is important in designing effective and safe biocontrol applications. Many species of Trichoderma have multiple strategies for fungal antagonism and indirect effects on plant health, such as growth promotion, systemic resistance induction and fertility improvements. Some strains are powerful antibiotic producers, and their suitability for use in biocontrol systems must be carefully assessed. However, many other active strains have no antibiotic cap…  相似文献   

11.
地表覆盖对旱地小麦氮磷钾需求及生理效率的影响   总被引:16,自引:3,他引:16  
【目的】研究地表覆盖对黄土高原旱地冬小麦氮磷钾需求和生理效率的影响,为促进黄土高原旱地冬小麦高效优质生产提供可靠的理论依据和实践经验。【方法】通过田间试验,以裸地休闲为对照,研究地膜覆盖、秸秆覆盖、种植绿肥和秸秆覆盖+种植绿肥对冬小麦籽粒产量、籽粒养分含量、籽粒产量形成和籽粒养分含量形成的氮磷钾需求及生理效率的影响。【结果】地膜覆盖降低了籽粒产量形成的需氮量,提高了籽粒产量形成的氮生理效率,从而使冬小麦籽粒产量显著增加6%;秸秆覆盖降低了地上部吸氮量,使籽粒产量减少7%;种植绿肥和秸秆覆盖+种植绿肥提高了籽粒产量形成的氮磷钾养分需求量、降低了籽粒产量形成的养分生理效率,从而使籽粒产量均减少5%。地膜覆盖提高了籽粒氮含量形成的需氮量,降低了氮生理效率,从而使籽粒含氮量降低8%,地膜覆盖增加了地上部吸钾量,使籽粒含钾量增加4%;秸秆覆盖的籽粒含氮量降低4%,但它的籽粒磷和钾含量分别提高6%和4%,这与降低籽粒磷钾含量形成的养分需求量、提高磷钾生理效率有关;种植绿肥提高了籽粒氮含量形成的氮生理效率,从而使籽粒氮含量增加8%;秸秆覆盖+种植绿肥对籽粒氮和磷含量无显著影响,但籽粒含钾量增加4%,归因于提高了籽粒钾含量形成的钾生理效率。【结论】地膜覆盖降低籽粒产量形成的需氮量,提高籽粒产量形成的氮生理效率,从而提高籽粒产量;但增加了籽粒氮含量形成的需氮量、降低了籽粒氮形成的氮生理效率,不利于籽粒含氮量提高。秸秆覆盖不利于作物养分吸收,从而影响籽粒产量和养分含量形成。种植绿肥和秸秆覆盖+种植绿肥提高了籽粒氮磷钾养分需求量、降低它们的生理效率,从而降低籽粒产量。种植绿肥可提高籽粒氮含量形成的氮生理效率,从而提高籽粒氮含量。因此,旱地小麦生产中为保证籽粒产量和营养品质,需增加地膜覆盖和秸秆覆盖的氮肥用量;夏闲期种植绿肥是旱地土壤培肥的重要措施,但需注意其可能带来的减产风险,应结合区域降水情况因地制宜。  相似文献   

12.
Intact erythrocytes placed into the tracheobronchial tree of hyperoxic rats dramatically improved their chances for survival. Over 70 percent of the animals so treated survived more than 12 days during continuous exposure to 95 percent oxygen, whereas all of the control animals died within 96 hours. Lungs from erythrocyte-protected rats showed almost none of the morphologic damage suffered by untreated animals. Erythrocytes containing cyanomethemoglobin were as beneficial as normal erythrocytes, but cells in which glutathione was partially blocked were significantly less protective. Analogous results were obtained in vitro: 51Cr-labeled target cells released 70 to 90 percent of their label when exposed briefly to hydrogen peroxide or to toxic oxygen species generated by phorbol ester-stimulated neutrophils. Addition of intact erythrocytes decreased release by approximately 75 percent, but significantly less than this if red blood cell glutathione was partially blocked. These results suggest that insufflated erythrocytes, through their recyclable glutathione, protect rats from toxic oxygen species engendered by hyperoxia.  相似文献   

13.
玉米生长空间对根系吸收特性的影响   总被引:34,自引:2,他引:34  
 在不供应和补充供应水、氮条件下 ,研究了限制根系生长空间对玉米根系生理特性、植株养分吸收及产量的影响。结果表明 ,限制根系生长空间虽严重影响了根系自身发育 ,降低了根系吸收总面积和TTC还原量 ,但却增加了根系的活跃吸收面积、比吸收表面、比活跃吸收表面 ,并提高了根系的TTC还原强度。这说明在限制根系生长的逆境条件下 ,作物并不是被动地忍受逆境的胁迫 ,而是主动地调节生理代谢过程 ,增强对水分和养分的吸收能力 ,从而减缓逆境的伤害。水、氮供应促进根系生长 ,增加根系吸收面积和活力 ,促进了根系对养分的吸收 ,从而提高了玉米产量 ,并减轻了因限制根系生长所引起的不良影响。  相似文献   

14.
Influences of root-growing space of maize upon root physiological characteristics, nutrient uptake and crop yields were studied under conditions with and without supply of water and N. Results showed that limitation of the root-growing space greatly affected root growth, decreased total root-absorbing area and TTC-reductive amounts. However, it obviously increased the root active-absorbing area, specific absorbing area (absorbing area per gram root weight) and specific active-absorbing area (actively absorbing area per gram root weight) in addition to promoting the TTC-reductive intensity. This clearly showed that plants were not passively tolerant to stress, but actively regulated their physiological metabolic processes, and strengthened their absorbing ability to increase water and nutrient uptake so that root injury by the environmental stress could be reduced. Supply of water and N stimulated root growth, increased root-absorbing area and activity, promoted nutrient uptake, and therefore increased crop yield and decreased the detrimental effects resulting from the limitation of roots-growing space.  相似文献   

15.
It is shown in physiological experiments conducted on goats and cows with the use of new methodological approaches that, with various methods of hormonal stimulation of galactopoiesis, intensification of milk protein synthesis is achieved mainly due to an increase of organ blood flow and activity of transport of metabolites into mammary secretory cells.  相似文献   

16.
During the three decades that have passed, medical science has ascended to a high plateau of achievement. The climb has involved several pathways; among them: (1) the physiological approach toward disease as experiments which nature performs on organisms, (2) the more intelligent interpretation of the functional reactions of the body in disease in accordance with latest discoveries in physiology, (3) the supplementation of observable phenomena through use of laboratory instruments, (4) the assumption of active investigation both on patients and experimental animals by clinicians themselves, (5) the shuttling of problems between clinical and experimental laboratories and (6) correlated research in clinical and physiological departments. As we look down from the heights we have reached, we have reason to be pleased with our progress; but when we look ahead we become aware that there are still high mountain ranges to be climbed. We realize that their ascent can not be accomplished by employing merely the methods, equipment and strategy that have proved successful so far; we must improve the application of principles that are old and well established, and evolve others that are new. Above all, we from laboratories and clinics must join hands to help each other climb; and through correlated team-work overcome the great obstacles that jealous nature places in our way. I have ventured to suggest a few directions which such mutual help may take. They include (1) means by which new fundamental discoveries can be utilized more quickly by clinicians and practitioners of medicine; (2) plans by which younger clinical investigators can be given approximately the same opportunity for training in research technique as their colleagues entering experimental sciences; (3) pleas that the shuttling of problems between hospitals and laboratories of fundamental science may continue in order that the ultimate significance of clinical results may be better understood and that the applicability of fundamental discoveries to nature's experiments may be tested; (4) judicious combination of talents of laboratory and clinical workers, whenever this leads to greater economy of effort and does not infringe upon the primary duties of each participant to his calling. The spirit of correlation which is involved in all these plans of advance is a silent force which grows not only through mutual interest in each other's problems but also through frank respectful criticism of each other's trends. With such a spirit of correlated effort science marches on.  相似文献   

17.
Global assessment of organic contaminants in farmed salmon   总被引:1,自引:0,他引:1  
The annual global production of farmed salmon has increased by a factor of 40 during the past two decades. Salmon from farms in northern Europe, North America, and Chile are now available widely year-round at relatively low prices. Salmon farms have been criticized for their ecological effects, but the potential human health risks of farmed salmon consumption have not been examined rigorously. Having analyzed over 2 metric tons of farmed and wild salmon from around the world for organochlorine contaminants, we show that concentrations of these contaminants are significantly higher in farmed salmon than in wild. European-raised salmon have significantly greater contaminant loads than those raised in North and South America, indicating the need for further investigation into the sources of contamination. Risk analysis indicates that consumption of farmed Atlantic salmon may pose health risks that detract from the beneficial effects of fish consumption.  相似文献   

18.
用含有矮生和不含矮生基因的8个小麦品种盆栽,定量浇以不同浓度的BR和GA_3,观察小麦初期生长反应。GA_3对供试品种芽鞘和叶的生长促进与矮生基因有关,即高杆种比矮杆种更敏感。BR对芽鞘的生长有促进作用,对叶的生长无明显影响,且均与矮生基因无关。GA_3既不促进各供试品种根的生长也不促进根的分化。BR在高浓度下对根的生长有明显抑制,但对某些品种初生根的发生具有促进作用。  相似文献   

19.
20.
Microwaves: effect on thermoregulatory behavior in rats   总被引:2,自引:0,他引:2  
Rats, with their fur clipped, pressed a lever to turn on an infrared lamp while in a cold chamber. When they were exposed to continuous-wave microwaves at 2450 megahertz for 15-minute periods, the rate at which they turned on the infrared lamp decreased as a function of the microwave power density, which ranged between 5 and 20 milliwatts per square centimeter. This result indicates that behaviorally significant levels of heating may occur at an exposure duration and intensities that do not produce measurable changes in many other behavioral measures or in colonic temperature. Further study of how microwaves affect thermoregulatory behavior may help us understand such phenomena as the reported "nonthermal" behavioral effects of microwaves.  相似文献   

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