抗巨片形吸虫同型抗体在动物巨片形吸虫感染所致的抗体依赖性细胞介导的细胞毒反应( ADCC )免疫应答作用的研究

以印尼短尾羊（ITT）和美利奴细毛羊（Merino）两种品系的绵羊为实验动物，研究动物感染巨片形吸虫后所产生的抗体依赖性细胞介导的细胞毒反应的免疫应答。结果显示：对巨片形吸虫感染具有抗性的印尼短尾羊不产生特异性的IgG2，而易感品系的美利奴细毛羊感染巨片形吸虫后体内产生高滴度特异性IgG2抗体、特异性IgG2抗体在免疫应答中起着封闭抗体的作用，抑制巨噬细胞抗体依赖性细胞介导的细胞毒反应。由于印尼短尾羊不产生特异性IgG2抗体，对巨噬细胞抗体依赖性细胞介导的细胞毒反应不产生抑制作用，因此印尼短尾羊对巨片形吸虫的感染具有一定的抵抗力。使用纯化的IgG1和IgG2进行体外杀虫试验，结果IgG1有很强的促进体外杀虫效果，而自感染巨片形吸虫的美利奴细毛羊血清标本纯化的IgG2没有体外杀虫作用。体外实验还显示嗜酸性粒细胞在免疫血清、补体和IL-5的共同参与下具有较强的杀虫作用。     

IL-21 initiates an alternative pathway to induce proinflammatory T(H)17 cells

On activation, naive T cells differentiate into effector T-cell subsets with specific cytokine phenotypes and specialized effector functions. Recently a subset of T cells, distinct from T helper (T(H))1 and T(H)2 cells, producing interleukin (IL)-17 (T(H)17) was defined and seems to have a crucial role in mediating autoimmunity and inducing tissue inflammation. We and others have shown that transforming growth factor (TGF)-beta and IL-6 together induce the differentiation of T(H)17 cells, in which IL-6 has a pivotal function in dictating whether T cells differentiate into Foxp3+ regulatory T cells (T(reg) cells) or T(H)17 cells. Whereas TGF-beta induces Foxp3 and generates T(reg) cells, IL-6 inhibits the generation of T(reg) cells and induces the production of IL-17, suggesting a reciprocal developmental pathway for T(H)17 and T(reg) cells. Here we show that IL-6-deficient (Il6-/-) mice do not develop a T(H)17 response and their peripheral repertoire is dominated by Foxp3+ T(reg) cells. However, deletion of T(reg) cells leads to the reappearance of T(H)17 cells in Il6-/- mice, suggesting an additional pathway by which T(H)17 cells might be generated in vivo. We show that an IL-2 cytokine family member, IL-21, cooperates with TGF-beta to induce T(H)17 cells in naive Il6-/- T cells and that IL-21-receptor-deficient T cells are defective in generating a T(H)17 response.     

Occurrence of anisakid larvae (Nematoda: Ascardidia) in fishes from Alaska and Idaho

All 25 sablefish ( Anoplopoma fimbria ) examined from two bays near Sitka, Alaska, were infected with anisakid larvae. There were 1 to 11 larvae per infected fish, with worms encysted in the musculature of the body wall of 5 fish and in the liver of 4 fish. For the other hosts the viscera was the site of infection. Chinook salmon ( Onchorhynchus tshawytscha ) from Barrow, Alaska, and Obsidian, Idaho, were also infected with anisakid larvae. These data extend the known northern distribution of the anisakids along the Pacific Coast for sablefish and chinook salmon. The pathogenesis of the migratory pathway of anisakid larvae is described, and comments on human health implications are presented.     

The worldwide leaf economics spectrum

Bringing together leaf trait data spanning 2,548 species and 175 sites we describe, for the first time at global scale, a universal spectrum of leaf economics consisting of key chemical, structural and physiological properties. The spectrum runs from quick to slow return on investments of nutrients and dry mass in leaves, and operates largely independently of growth form, plant functional type or biome. Categories along the spectrum would, in general, describe leaf economic variation at the global scale better than plant functional types, because functional types overlap substantially in their leaf traits. Overall, modulation of leaf traits and trait relationships by climate is surprisingly modest, although some striking and significant patterns can be seen. Reliable quantification of the leaf economics spectrum and its interaction with climate will prove valuable for modelling nutrient fluxes and vegetation boundaries under changing land-use and climate.     

Large temperature drop across the Eocene-Oligocene transition in central North America

The Eocene-Oligocene transition towards a cool climate (approximately 33.5 million years ago) was one of the most pronounced climate events during the Cenozoic era. The marine record of this transition has been extensively studied. However, significantly less research has focused on continental climate change at the time, yielding partly inconsistent results on the magnitude and timing of the changes. Here we use a combination of in vivo stable isotope compositions of fossil tooth enamel with diagenetic stable isotope compositions of fossil bone to derive a high-resolution (about 40,000 years) continental temperature record for the Eocene-Oligocene transition. We find a large drop in mean annual temperature of 8.2 +/- 3.1 degrees C over about 400,000 years, the possibility of a small increase in temperature seasonality, and no resolvable change in aridity across the transition. The large change in mean annual temperature, exceeding changes in sea surface temperatures at comparable latitudes and possibly delayed in time with respect to marine changes by up to 400,000 years, explains the faunal turnover for gastropods, amphibians and reptiles, whereas most mammals in the region were unaffected. Our results are in agreement with modelling studies that attribute the climate cooling at the Eocene-Oligocene transition to a significant drop in atmospheric carbon dioxide concentrations.     

The montane bee fauna of north central Washington, USA, with floral associations

The mountains of north central Washington contain a variety of habitat types, from shrubsteppe to high alpine meadows. While native bee surveys of some surrounding areas like the Columbia Basin are fairly complete, little work has been done in the mountains of north central Washington to document the diversity of bees found therein. We conducted a survey of native bees in the Tonasket Ranger District of the Okanogan-Wenatchee National Forest during summer 2004. Collections yielded a diverse bee fauna (140 species in 24 genera) visiting diverse floral elements (57 plant species in 18 families). These preliminary data suggest that a rich bee fauna exists in the Okanogan Basin and surrounding mountains.     

Diel use of water by reintroduced bighorn sheep

Water sources are an important habitat component for populations of bighorn sheep ( Ovis canadensis ), and the technique of sampling at water sources has been used extensively to study behaviors and estimate parameters of bighorn populations. Little is known, however, concerning the time of day at which groups of bighorns visit water. Understanding when bighorns visit water sources will allow wildlife investigators to conduct sampling when bighorns are most likely to be present at this resource. We quantified use of 7 water sources by reintroduced bighorn sheep during summer 2005 and 2006 on Antelope Island State Park, Utah. Our purpose was to determine if female, male, or mixed-sex groups visited water at a particular time and if visits to this resource by all bighorns differed in time during drought conditions compared with nondrought conditions. The mean time that all bighorns visited water was 14:22 ( s = 3:08 hours). No time differences existed among female, male, or mixed-sex groups or between drought and nondrought conditions. Our results provide wildlife investigators with a time frame for activating motion-sensor cameras or sampling at water sources, which will increase the likelihood of photographing or observing reintroduced Rocky Mountain bighorn sheep at water sources in portions of the Great Basin Desert.     

Perceptions of Utah alfalfa growers about wildlife damage to their hay crops: implications for managing wildlife on private land

We conducted a survey of Utah alfalfa ( Medicago sativa ) growers in 1993 to identify wildlife damage problems to bay crops. Such surveys can provide wildlife managers with important insights regarding landowners' wildlife damage management concerns and needs. Pocket gophers ( Thomomys spp.) and mule deer ( Odecoileus hemionus ) were perceived by growers as causing the most damage. Respondents reported a total annual loss of $350,000 or $24.79/ha (2.8% of the total crop value) because wildlife damage in alfalfa crops. Decreased hay quantity was the most frequently cited problem caused by wildlife. Compensation and incentive programs were preferred over assistance and information programs for managing wildlife damage in alfalfa crops.