总被引：5，自引：0，他引：5  

CAROLYN M. OATES  J. F. BISSENDEN  R. N. MAINI  L. N. PAYNE  D. C. DUMONDE 《Nature: New biology》1972,239(92):137-139

AMONG the soluble products generated during activation of rodent or human lymphocytes¹, lymphocyte-stimulating (‘mitogenic’) factors are detected by their ability to accelerate DNA metabolism of freshly cultured allogeneic or syngeneic lymphocytes^2–8. If such lymphocyte activation products function as mediators of cellular immunity^1,9–11, their activities will be generated independently of the antibody-forming system. In the chicken, antigen-stimulation of sensitized lymphocytes in vitro involves both thymus (T-) and bursa-(B-)-dependent cells^12–14. If antigen-induced lymphocyte transformations are generally mediated by lymphocyte mitogenic factors, both T-cells and B-cells should produce lymphocyte mitogenic factors when stimulated by specific antigen. We have therefore determined whether antigen-stimulated chicken lymphocytes generate a lymphocyte mitogenic factor and whether this response is affected by neonatal thymectomy or bursectomy.  相似文献   

    

LIVREA G  DE STEFANO F  PICCIOTTO A 《Biologica Latina》1958,11(3):429-436

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Glutamic oxalacetic transaminase and glutamic pyruvic transaminase in guinea pig organ autolysates     

TROPEANO L  NUNNARI A  DI STEFANO S  BELFIORE F 《Bollettino della Società italiana di biologia sperimentale》1958,34(18):1141-1144

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Glutamic oxalacetic transaminase and glutamic pyruvic transaminase in guinea pig tissue homogenates     

TROPEANO L  NUNNARI A  DI STEFANO S  BELFIORE F 《Bollettino della Società italiana di biologia sperimentale》1958,34(18):1138-1141

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Contrasting signals from multiple markers illuminate population connectivity in a marine fish     

MARIA SALA‐BOZANO  VALERIO KETMAIER  STEFANO MARIANI 《Molecular ecology》2009,18(23):4811-4826

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DI STEFANO HS  DIERMEIER HF 《The journal of histochemistry and cytochemistry》1959,7(2):83-85

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JAN CHRISTIAN HABEL  DENNIS RÖDDER  SCALERCIO STEFANO  MARC MEYER  THOMAS SCHMITT 《Biological journal of the Linnean Society. Linnean Society of London》2010,99(4):818-830

The sea acts as an effective dispersal barrier for most terrestrial animal species. Narrow sea straits, therefore, often represent areas where species are able to disperse from one land mass to another. In the Mediterranean Sea, the narrowest connecting points between North Africa and Europe are the Strait of Gibraltar and the Strait of Sicily. In the past, climatic oscillations caused changing sea levels and thus influenced the permeability of these sea straits. We analysed the genetic structure of four butterfly species that all occur on both sides of the Strait of Sicily. In all four species, we observed a lack of genetic differentiation between the populations of North Africa and those of Italy. Species distribution models support the strong cohesiveness in that they show a largely continuous glacial distribution over Italy and North Africa. The data obtained reveal that there was a large exchange of individuals between Italy and the eastern Maghreb during the last ice age. This might not only be the case for the species under investigation in the present study, but also might represent a more general pattern for mobile thermophilic western Palearctic species. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 818–830.  相似文献   

    

DI STEFANO V  CAMBRIA A 《Bollettino della Società italiana di biologia sperimentale》1953,29(5):959-960

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JULIAN DI STEFANO  ALAN YORK  MATTHEW SWAN  ANDREW GREENFIELD  GRAEME COULSON 《Austral ecology》2009,34(2):143-155

Patterns of resource selection by animals may be influenced by sex, and often change over a 24‐h period. We used a dry sclerophyll landscape managed for commercial timber production to investigate the effects of sex and diel period on habitat selection by the swamp wallaby (Wallabia bicolor). We predicted that selection would be (i) affected by both sex and diel period; and (ii) positively related to lateral cover during the day, but to food resources at night. Non‐metric multidimentional scaling indicated that some of the available habitats differed markedly with respect to visibility (an indicator of lateral cover), fern cover, forb cover, wallaby density and a forage quality index, providing the basis for non‐random habitat selection. At the landscape scale, wallabies showed strong selection for 5‐year‐old regenerating sites, selected against 10‐year‐old regenerating sites and unharvested forest, and avoided recently harvested (3–10 months post‐harvest) sites completely. At the scale of individual home ranges, a pooled male and female sample demonstrated selection for unharvested forest over recently harvested sites during both diurnal and nocturnal periods. A separate analysis showed that both sex and diel period influenced the selection of 5‐ and 10‐year‐old sites and the surrounding unharvested forest. Using a novel approach, we demonstrated that diurnal habitat selection by both sexes was negatively correlated with visibility, representing stronger selection for areas with more lateral cover. Nocturnal selection by females was positively correlated with values of a forage quality index, but this was not the case for males. We hypothesise that the observed patterns of selection were driven by the need to find food and avoid predators, but were also affected by the different reproductive strategies of males and females. Our results demonstrate the importance of incorporating factors such as sex and diel period into analyses of habitat selection.  相似文献   

    

GUILLAUME DAUPHIN  PATRICK COQUILLARD  STEFANO COLAZZA  EZIO PERI  ÉRIC WAJNBERG 《Ecological Entomology》2009,34(2):193-203

Abstract 1. Trissolcus basalis (Wollaston) (Hymenoptera: Scelionidae) is an egg parasitoid that recognises chemical residues left by its host the green stink bug Nezara viridula (L.) (Heteroptera: Pentatomidae) as kairomone signals, enabling it to find egg masses in which to lay eggs. 2. Kairomones are usually present as patches deposited by N. viridula females, and recent results (Peri et al., Journal of Experimental Biology, 209 , 3629–3635, 2006) indicated that females of T. basalis are able to learn the features of their foraging environment and to adjust accordingly the amount of time spent on the patches of kairomones they are visiting, depending on whether or not host eggs are found. 3. In order to assess the impact of this learning ability, a Monte Carlo, spatially explicit and individual‐based simulation model was built to quantify the foraging efficiency of T. basalis females in environments with different levels of host abundance and distribution. In all cases, the present study compared the foraging efficiency of simulated T. basalis females having the ability to learn with those lacking this ability. 4. Learning females always visited a higher number of kairomone patches and attacked a higher number of hosts than non‐learning females, especially when there was a high density of kairomone patches in the environment. 5. Learning ability globally appears to allow the maintenance of efficient foraging success, especially when there is a low probability for the kairomone patches to contain discoverable hosts. 6. The increase in foraging efficiency for learning females appears to depend on the characteristics of the habitat in which they are foraging. Results thus suggest that significant variation in learning ability is likely to occur in natural wasp populations facing different environments with different host spatial distributions.  相似文献