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1.
Invaders, weeds and colonizers comprise different but overlapping sets of species. The probability of successful invasion is low. The 10:10 rule state that 10% of introduced speices (those with feral individuals) become established, 10% of established species (those with self-sustaining populations) become pests. The rule gives an adequate fit to British plant data. The rule predicts that invaders will be rarer than natives. This is shown for British Anatidae. There is a continuous spectrum of perceived weediness. Although this spectrum is significantly related to Baker characters, neither those characters or any others can usefully predict which species will be weeds over a wide range of species. Characters tuned to sets of closely related species shown more promise. A study of BritishImpatiens shows that the characters responsible for critical ecological behaviour are still obscure. Small genetic changes can cause large ecological changes. GMOs will have characters entirely new to that species' evolutionary history. While most will have little ecological effect, a few may be ecologically and economically damaging. A sensible programme of field trials and monitoring is justified to minimize the risk.  相似文献   

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JAKs and STATs in invertebrate model organisms   总被引:5,自引:0,他引:5  
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The capacity of organisms to sense changes in the levels of internal and external gases and to respond accordingly is central to a range of physiologic and pathophysiologic processes. Carbon dioxide, a primary product of oxidative metabolism is one such gas that can be sensed by both prokaryotic and eukaryotic cells and in response to altered levels, elicit the activation of multiple adaptive pathways. The outcomes of activating CO2-sensitive pathways in various species include increased virulence of fungal and bacterial pathogens, prey-seeking behavior in insects as well as taste perception, lung function, and the control of immunity in mammals. In this review, we discuss what is known about the mechanisms underpinning CO2 sensing across a range of species and consider the implications of this for physiology, disease progression, and the possibility of developing new therapeutics for inflammatory and infectious disease.  相似文献   

5.
Zusammenfassung Milzzellenaufschwemmungen von Mäusen, die mit einem Gemisch von Schaf- und Hühnererythrocyten einmal injiziert wurden, verursachen lokalisierte, hämolytische Zonen (antibody plaques), die nicht aus den beiden Zelltypen, sondern entweder nur aus Schaf- oder nur aus Hühnerzellen bestehen. Lymphatische Zellen, die gleichzeitig zwei verschiedene Hämolysine abscheiden können, sind in Milzzellenaufschwemmungen von zweifach immunisierten Mäusen anscheinend abwesend oder nur in ganz geringer Anzahl vorhanden.

The capable technical assistance of Mrs.Leony Mills during these studies is acknowledged. This investigation was supported in part by the U.S. National Science Foundation (Grant G-19581).  相似文献   

6.
Zusammenfassung Die Kinetik der Induktion von Plaques in Einschichtenzellkulturen wurde bei 20° und 36°C bestimmt. Es nimmt die Zahl der durch RNS induzierten Plaques in den ersten 8 bis 10 min nach Kulturbeimpfung schnell und dann allmählich langsamer zu. Die möglichen Ursachen dieses Verhaltens werden diskutiert.  相似文献   

7.
Myosins are a large family of actin-based motor proteins that are involved in a variety of cellular processes. Class II, or conventional, myosins are organized into a number of multi-component structures such as muscle thick filaments, non-muscle filaments and the actomyosin ring during cell division. A number of conditions must be met for the proper assembly and organization of myosin II-containing structures, including the correct stoichiometry of myosin and its associated proteins, and the conformation and regulation of the myosin molecule itself by molecular chaperones and protein kinases. In this review we discuss the use of model organisms in the genetic analysis of the assembly and organization of myosin-containing structures.  相似文献   

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Understanding the basic biology of human ageing is a key milestone in attempting to ameliorate the deleterious consequences of old age. This is an urgent research priority given the global demographic shift towards an ageing population. Although some molecular pathways that have been proposed to contribute to ageing have been discovered using classical biochemistry and genetics, the complex, polygenic and stochastic nature of ageing is such that the process as a whole is not immediately amenable to biochemical analysis. Thus, attempts have been made to elucidate the causes of monogenic progeroid disorders that recapitulate some, if not all, features of normal ageing in the hope that this may contribute to our understanding of normal human ageing. Two canonical progeroid disorders are Werner's syndrome and Hutchinson-Gilford progeroid syndrome (also known as progeria). Because such disorders are essentially phenocopies of ageing, rather than ageing itself, advances made in understanding their pathogenesis must always be contextualised within theories proposed to help explain how the normal process operates. One such possible ageing mechanism is described by the cell senescence hypothesis of ageing. Here, we discuss this hypothesis and demonstrate that it provides a plausible explanation for many of the ageing phenotypes seen in Werner's syndrome and Hutchinson-Gilford progeriod syndrome. The recent exciting advances made in potential therapies for these two syndromes are also reviewed.  相似文献   

11.
Zusammenfassung In der löslichen Fraktion der Rinderzahnpulpa wurde die Aminoxydase gereinigt und die Enzymaktivität durch Isoniazid, Cuprizon,p-Chloromercuribenzoat,-Aminoproprionitril und Lysin-Vasopressin gehemmt. Die Aminoxydase hat wahrscheinlich Kupfer und Pyridoxalphosphat als prosthetische Gruppen.  相似文献   

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Summary Injection of cadmium chloride to rats fed by normal calcium diet induced disturbances of tibia and incisor hard tissues metabolism. It is suggested that there may be the possibility of direct cadmium actions on those hard tissues metabolisms.Acknowledgment. The author wishes to thank Professor Yasumi Ogura for his valuable advices concerning this work.  相似文献   

14.
H Furuta 《Experientia》1978,34(10):1317-1318
Injection of cadmium chloride to rats fed by normal calcium diet induced distrubances of tibia and incisor hard tissues metabolism. It is suggested that there may be the possibility of direct cadmium actions on those hard tissues metabolisms.  相似文献   

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Halfway through the paper in which he laid down the foundations for the theory of special relativity, Einstein concludes that “the asymmetry mentioned in the Introduction … disappears.” Making asymmetry disappear has proved to be one of Einstein's many significant moves in his annus mirabilis of 1905. This elimination of asymmetry has led many commentators to claim that Einstein was motivated by either an aesthetic or an epistemic argument which gives priority to symmetry over asymmetry. Following closely the development of electrodynamics in the period from 1880 to 1905 and the usage of the related terms reciprocity and symmetry, we suggest a different way of understanding Einstein's motivation and the path he took. In contrast to the received view, we argue that Einstein responded to a debate in the literature on electrodynamics and that he was concerned neither with an aesthetic nor with an epistemic argument; rather, his reasoning was physical in the best sense, and most original. We will show that by providing a new perspective on the relation between electricity and magnetism, Einstein succeeded in bringing the discussion of symmetry in electrodynamics to an end.  相似文献   

18.
Vesicomyid and lucinid clams and tubeworms from Gulf of Mexico petroleum seeps, all of which bear symbiotic sulfide-oxidizing bacteria, have much lower catalase activities than shallow-water species lacking symbionts. A petroleum seep mussel bearing methane-oxidizing bacteria is unusual in having catalase activities as high as shallow-water bivalves. Unlike sulfide-dependent meiofauna from shallow-water marine sands, catalase from all petroleum seep species was inhibited by 3-amino-1,2,4-triazole.Acknowledgments. We thank S. McDonald and the crew of R/V Gyre for assistance in animal collection. This research was funded by NSF grant OCE-8219792 to EP and NSF grant OCE-83-01538 and funds from the Offshore Operators Committee to J. Brooks. We appreciate this support.  相似文献   

19.
Riassunto Viene descritto un metodo di dosaggio della metilguanidina nel siero e nell'urina e vengono riportati i valori normali della concentrazione serica (0.008±0.002 mg/100 ml) e della eliminazione urinaria (1.83±0.29 mg/24 h). Tanto la concentrazione serica quanto la eliminazione urinaria degli uremici sono risultate elevate.

Supported by the National Institutes of Health (Contract No. PH-43-68-1466).  相似文献   

20.
The evolution of cocci and diphtheroids taking origin from cell-wall-deficient forms seems not to be related to a particular state of illness, but to be the consequence of a generalized crypto-infection.  相似文献   

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