关键词： Basal resources   Mycorrhiza   Pulse labeling   Rhizodeposits   Stable isotopes  

摘要： Root-derived resources are receiving increased attention as basal resources for soil animal food webs. They predominantly function as carbon and energy resources for microbial metabolism in the rhizosphere, however, root-derived nitrogen may also be important. We explored both the role of root-derived carbon (C) and nitrogen (N) for the nutrition of soil animal species. Using C-13 and N-15 pulse labeling we followed in situ the flux of shoot-derived C and N into the soil animal food web of young beech (Fagus sylvatica) and ash (Fraxinus excelsior) trees. For labeling with C-13, trees were exposed to increased atmospheric concentrations of (CO2)-C-13 and for labeling with N-15 leaves were immersed in a solution of (CaNO3)-N-15. Twenty days after labeling root-derived N was detected in each of the studied soil animal species whereas incorporation of root-derived C was only detected in the ash rhizosphere. More root-derived N was incorporated into soil animals from the beech as compared to the ash rhizosphere, in spite of the higher N-15 signatures in fine roots of ash as compared to beech. The results suggest that soil animal food webs not only rely on root C but also on root N with the contribution of root N to soil animal nutrition varying with tree species. This novel pathway of plant N highlights the importance of root-derived resources for soil animal food webs. (C) 2017 Gesellschaft fur Okologie. Published by Elsevier GmbH. All rights reserved.

关键词： Fermentation   Gas production   Chemical composition   Prickly pear  

摘要： In production systems of prickly pear fruit and prickly pear cactus, significant amounts of pruned material, which could be used as an ingredient in animal feeding, is generated. The aim of this study was to measure the nutrient content, fermentation kinetics and in vitro digestibility of eleven cultivars of cladodes of prickly pear cactus. The fermentation was measured indirectly using the gas production technique, where 500 mg of DM substrate (prickly pear cactus cultivars) were placed in amber glass flasks of 125 mL with 90 mL of ruminal inoculum under a continuous flow of CO2. Flasks were hermetically wrapped up with a rubber stopper and a metal ring, and were placed in a water bath at 39 degrees C. The fermentation gas pressure was measured using a monometer at 0, 2, 4, 6, 8, 12, 16, 20, 24, 32, 38, 50 and 72 h incubation. Results show that the chemical composition ranged between (g kg(-1) DM): 64 and 160 g kg(-1) dry matter (DM), 137-293 g kg(-1) DM ash, 52-101 g kg(-1) DM crude protein, 3-22 g kg(-1) DM ether extract, 251-393 neutral detergent fiber and 132-192 acid detergent fiber. The gas volume was different (p < 0.05) among cultivars, with the Red Vigor cultivar having the largest volume at 378 mL g(-1) DM. The highest volume of gas was produced during the first 24 h in on average 67 % of the total produced. The in vitro DM digestibility displayed values of up to 82 % in the Roja Pelota cultivar. It can be concluded that the cladodes of prickly pear cactus from different cultivars can be used in animal feed for its good rumen fermentation characteristics.

关键词： Zinc oxide nanoparticles   Reactive oxygen species   Oxidative stress   Alginate   Gum acacia   Horse   Lipid peroxidation   MDA   Hemolytic activity  

摘要： Zinc oxide nanoparticles are important nanomaterials currently under research due to their applicability in nanomedicine. Toxicity of ZnO NPs has been extensively studied and has been shown to affect various cell types and animal systems. In this study, we investigated hemolytic potential and oxidative stress inflicted by ZnO NPs and ZnO NPs-loaded-sodium alginate-gum acacia hydrogels on horse erythrocytes and African green monkey kidney (Vero) cells. Our study provides a better understanding of the hemolytic and oxidative effects of interaction of ZnO NPs and ZnO NPs released from polymeric hydrogels with the biological system. Remarkable aggregation of erythrocytes was noted in the higher concentration of ZnO NPs treated erythrocytes as compared to erythrocytes treated with ZnO NPs-loaded hydrogels. ZnO NPs-loaded hydrogels treated Vero cells significantly reduced oxidative stress as evidenced by less malondialdehyde production as compared to that of ZnO NPs treated cells. Normal horse erythrocytes when treated with ZnO NPs in in vitro condition undergo oxidative damage, and contribute in augmenting the toxicity. We demonstrated that polymeric ZnO NPs reduced the undesirable effects provoked by ZnO NPs on mammalian cells. (C) 2017 Elsevier B.V. All rights reserved.

关键词： ANIMAL migration   EFFECT of climate on animal migration   SAVANNAS   FOOD chains (Ecology)   AFRICA   SERENGETI Plain (Tanzania)  

摘要： The article discusses importance of animal migration for sustenance of Africa's freshwater food webs. Topics include effect of climate and man-made walls on great migrations, effect of extinction of animal migrations, mass drownings of Serengeti wildebeest in Mara river, animal carcasses adding to river biomass being pathway to carbon and nitrogen production.

关键词： brush management   cattle   endozoochory   Prosopis glandulosa   seeds   woody plant invasion  

摘要： The dispersal of woody plant seeds by livestock has been implicated as one of the causes of woody plant encroachment in semiarid ecosystems worldwide. In the southern Great Plains, United States, cattle are suspected to have increased encroachment of the woody legume honey mesquite (Prosopis glandulosa Torr.) because they are effective consumers of mesquite pods and pass viable seed from those pods through their digestive systems. Since other animal species also consume or gather mesquite pods and seeds, our objective was to compare the removal of mesquite pods by cattle, other vertebrate herbivores, and insects. Mature pods were collected from trees in late summer and placed within each level of a hierarchical exclusion design using fences and cages that blocked cattle;other large vertebrates (deer, feral hogs);smaller vertebrates (rabbits, birds, rodents);and insects at replicate sites in north and south Texas locations. Pod removal was quantified during 60-d trials in the fall of each of 3 yr. The treatment that allowed cattle to have access to pods had the greatest or tied for the greatest pod removal at trial end in all trials. Final pod removal in the feral hog and white-tailed deer treatments was numerically lower but statistically similar (P <= 0.05) to cattle. However, the rate of pod removal during the first 20 din several of the trials was greatest (P <= 0.05) in the cattle treatment at both locations. Pod removal by rodents was high in 1 yr at both locations, which we attributed to high growing season precipitation at both locations during that year. Results may have implications regarding seed-centric grazing management decisions and keeping cattle out of pastures when mesquite pods are abundantly present on the ground. (C) 2017 The Society for Range Management. Published by Elsevier Inc. All rights reserved.

关键词： Rule extraction   Reproduction   Animal personality   Animal behavior   Internal states   Fitness  

摘要： The connection between reproductive fitness and animal personality is not fully understood. Using computer simulations and machine learning, we found high accuracy rules that predict which personalities are associated with fitness for two correlated measures of components of fitness applied a posteriori for classificatory purposes: fitness component (1) in terms of survival and short-term reproductive success, and fitness component (2) in terms of long term reproductive success which is indirectly related to survival of the parents. Animals are represented in the abstract as individuals with a genome that through time develops into certain characteristic behaviors and personalities. To the best of our knowledge, this is the first simulation study of its kind that extracts rules to investigate the link between personality and fitness. Clearly separated behaviors between fit and non-fit individuals emerged through the evolution of the population over time without top-down processing. Moreover, we did not employ a pre-defined fitness function, in order to minimize any possible biases toward a specific type of behavior. With respect to fitness component (1), we found that individuals with one of two extreme values of a personality trait (either bold or fearful) tend to be most fit, which agrees with empirical studies. With respect to fitness component (2), we found that when resources are low, fit individuals search for food whereas if food is abundant, they focus on reproduction, thereby suggesting the context dependence of fitness related behaviors. Once again, these results agree with empirical studies.

关键词： defaunation   density-dependent transmission   exclosure   nematode   population regulation   wildlife decline  

摘要： Biodiversity loss can alter disease transmission;however, the magnitude and direction of these effects vary widely across ecosystems, scales, and pathogens. Here we experimentally examine the effects of one of the most globally pervasive patterns of biodiversity decline, the selective loss of large wildlife, on infection probability, intensity and population size of a group of common rodent-borne parasites - macroparasitic helminths. Consistent with previous work on vector-borne pathogens, we found that large wildlife removal causes strong and systematic increases of rodent-borne parasites, largely due to increases in rodent density, as rodents are released from competition with larger herbivores. Although we predicted that increased host density would also increase per capita infection among all directly transmitted parasites, this additional amplification occurred for only two of three examined parasites. Furthermore, the actual effects of large mammal loss on per capita infection were mediated by the complex suite of abiotic and biotic factors that regulate parasite transmission. Thus, while these results strongly suggest that large wildlife loss will cause systematic increases in rodent parasite populations, they also underscore the difficulty of making more specific predictions for a given parasite based on simple attributes such as transmission mode or life history strategy. Instead, detailed information on the ecology of each parasite species would be necessary to make more accurate predictions of how biodiversity loss will affect infection.

关键词： Blood-brain barrier   stroke   focal ischemia   neurovascular unit   endothelium  

摘要： Stroke-induced blood-brain barrier breakdown promotes complications like cerebral edema and hemorrhagic transformation, especially in association with therapeutical recanalization of occluded vessels. As arteries, capillaries and veins display distinct functional and morphological characteristics, we here investigated patterns of blood-brain barrier breakdown for each segment of the vascular tree in rodent models of embolic, permanent, and transient middle cerebral artery occlusion, added by analyses of human stroke tissue. Twenty-four hours after ischemia induction, loss of blood-brain barrier function towards FITC-albumin was equally observed for arteries, capillaries, and veins in rodent brains. Noteworthy, veins showed highest ratios of leaky vessels, whereas capillaries exhibited the most and arteries the least widespread perivascular tracer extravasation. In contrast, human autoptic stroke tissue exhibited pronounced extravasations of albumin around arteries and veins, while the pericapillary immunoreactivity appeared only faint. Although electron microscopy revealed comparable alterations of the arterial and capillary endothelium throughout the applied animal models, structural loss of arterial smooth muscle cells was only observed in the translationally relevant model of embolic middle cerebral artery occlusion. In light of the so far available concepts of stroke treatment, the consideration of a differential vascular pathophysiology along the cerebral vasculature is likely to allow development of novel effective treatment strategies.

关键词： 转基因树   世界   动物   昆明   中科院   体外培养体系   精原干细胞   中国科学院  

摘要： 据2017年1月5日《中国科学报》报道，中国科学院昆明动物所郑萍、赵旭东和姚永刚三个课题组共同建立了树嗣精原干细胞体外培养体系，并利用体外培养的树嗣精原干细胞获得世界首只转基因树嗣，实现了树驹基因修饰技术的突破。相关成果发表在《细胞研究》杂志。

摘要： A new nematode Parapharyngodon hugoi n. sp. (Oxyuroidea: Pharyngodonidae) is described parasitising the large intestine of the tree frog Trachycephalus typhonius (Linnaeus) (Anura: Hylidae) from the wetlands of Pantanal, State of Mato Grosso do Sul, Brazil. The new species exhibits a unique structure of the posterior cloacal lip in males, which is supported by a rigid V-shaped structure. Parapharyngodon hylidae parasitic in hylid frogs, including T. typhonius, from Mexico, is the most similar congener to P. hugoi n. sp. but is distinguished from the new species by the presence of a gubernaculum (vs absence), by the lateral alae in males ending far anterior to cloacal opening (vs near to it) and because in gravid females the ovaries encircle the oesophageal corpus. Additionally, the new species differs from its congeners as well as from species of Thelandros Wedl, 1862, a very closely related genus, by the combination of features such as spicule length, number of caudal papillae, morphology of the anterior cloacal lip, which is echinate, and position of ovaries. The geographical distribution of hosts seems to play an important role in the speciation process of Parapharyngodon spp.;however, due the lack of molecular data this issue along with the validity of both Thelandros and Parapharyngodon are still questions to be solved in the future, after improvement of the genetic database. A key to the species of Parapharyngodon parasitic in amphibians from the American continent is provided.