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231.
In colonial species, first‐time breeders may use the number of settled conspecifics in colony selection, but such a relationship is confused by the correlation between colony size and nest‐site availability. To distinguish conspecific attraction from neutral colony selection, we experimentally increased nest availability for first‐year Lesser Kestrels Falco naumanni, allowing us to dissociate the number of vacant nest‐sites from colony size at the arrival time of first‐year birds. Under natural conditions, the number of first‐year birds settling was positively correlated with both the number of philopatric and the total number of breeding pairs (colony size) already settled. However, the probability of occupation of experimentally manipulated nests by first‐year birds was independent of colony size. In experimental colonies, the number of first‐year birds settling was positively correlated with the number of manipulated nest‐sites but not with the number of conspecifics. Overall, these results support a neutral colony selection by first‐year Lesser Kestrels based on nest‐site availability. 相似文献
232.
233.
Noha Ahmed El Boghdady 《Cell biochemistry and function》2013,31(4):344-351
Grape seed proanthocyanidins (GSPE) and ginkgo biloba extract (EGb761) are considered to have protective effects against several diseases. The cardiotoxicity of doxorubicin (DOX) has been reported to be associated with oxidative damage. This study was conducted to evaluate the cardioprotective effects of GSPE and EGb761 against DOX‐induced heart injury in rats. DOX was administered as a single i.p. dose (20 mg kg–1) to adult male rats. DOX‐intoxicated rats were orally administered GSPE (200 mg kg–1 day–1) or EGb761 (100 mg kg–1 day–1) for 15 consecutive days, starting 10 days prior DOX injection. DOX‐induced cardiotoxicity was evidenced by a significant increase in serum aspartate transaminase (AST), creatine phosphokinase isoenzyme (CK‐MB), lactate dehydrogenase (LDH), total cholesterol (TC) and triglyceride (TG) activities and levels. Increased oxidative damage was expressed by the depletion of cardiac reduced glutathione (GSH), elevation of cardiac total antioxidant (TAO) level and accumulation of the lipid peroxidation product, malondialdehyde (MDA). Significant rises in cardiac tumour necrosis factor‐alpha (TNF‐α) and caspase‐3 levels were noticed in DOX‐intoxicated rats. These changes were ameliorated in the GSPE and EGb761‐treated groups. Histopathological analysis confirmed the cardioprotective effects of GSPE and EGb761. In conclusion, GSPE and EGb761 mediate their protective effect against DOX‐induced cardiac injury through antioxidant, anti‐inflammatory and antiapoptotic mechanisms. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
234.
Bees (Apidae), of which there are more than 19 900 species, are extremely important for ecosystem services and economic purposes, so taxon identity is a major concern. The goal of this study was to optimize the DNA barcode technique based on the Cytochrome c oxidase (COI) mitochondrial gene region. This approach has previously been shown to be useful in resolving taxonomic inconsistencies and for species identification when morphological data are poor. Specifically, we designed and tested new primers and standardized PCR conditions to amplify the barcode region for bees, focusing on the corbiculate Apids. In addition, primers were designed to amplify small COI amplicons and tested with pinned specimens. Short barcode sequences were easily obtained for some Bombus century‐old museum specimens and shown to be useful as mini‐barcodes. The new primers and PCR conditions established in this study proved to be successful for the amplification of the barcode region for all species tested, regardless of the conditions of tissue preservation. We saw no evidence of Wolbachia or numts amplification by these primers, and so we suggest that these new primers are of broad value for corbiculate bee identification through DNA barcode. 相似文献
235.
Invasions by exotic toxic prey, like the release of the South American cane toad (Bufo (Rhinella) marinus) to the toad‐free Australian continent in 1935, have been shown to result in massive declines in native predator numbers. Due to minor nucleotide mutations of the Na+/K+‐ATPase gene most Australian squamate predators are highly susceptible to cane toad toxin. However, in spite of this, predators like yellow‐spotted goannas (Varanus panoptes) and red‐bellied black snakes (Pseudechis porhyriacus) still persist in parts of Queensland where they, in some areas, have co‐existed with cane toads for more than 70 years. Here, we show that the amino acids of the Na+/K+‐ATPase enzyme in the two species do not provide toad toxin resistance, and hence the two Queensland predators are still highly susceptible to cane toad toxin. Both yellow‐spotted goannas and lace monitors (Varanus varius) have, however, been recorded avoiding feeding on cane toads in areas where they co‐exist with this toxic amphibian. Moreover, both varanids have also been shown to learn to avoid feeding on toads when first subjected to conditioned taste aversion. Such behavioural shifts may therefore explain why yellow‐spotted goannas and red‐bellied black snakes still exist in cane toad infested areas of Queensland. The process appears, however, to be unable to rapidly restore varanid populations to pre‐toad population numbers as even after 10 years of co‐existence with cane toads in the Northern Territory, we see no signs of an increase in yellow‐spotted goanna numbers. 相似文献
236.
Harakawa S Inoue N Hori T Tochio K Kariya T Takahashi K Doge F Suzuki H Nagasawa H 《Bioelectromagnetics》2005,26(7):589-594
The effects of exposure to extremely low frequency electric fields (ELF EFs) on plasma lipid peroxide levels and antioxidant activity (AOA) in Sprague-Dawley rats were studied. The test was based on comparisons among rats treated with a combination of the oxidizing agent, 2,2'-azobis(2-aminopropane) dihydrochloride (AAPH) and 50 Hz EF of 17.5 kV/m intensity for 15 min per day for 7 days, AAPH alone, EF alone or no treatment. EF significantly decreased the plasma peroxide level in rats treated with AAPH, similar to treatment by ascorbic acid or the superoxide dismutase. Ascorbic acid increased AOA; however, EF and superoxide dismutase did not change AOA compared with sham exposure in stressed rats. No influence on the lipid peroxide level and AOA in unstressed rats was observed with EF exposure alone. Although the administration of AAPH decreased AOA, this decrease did not change when EF was added. These data indicate that the ELF EF used in this study influenced the lipid peroxide level in an oxidatively stressed rat. 相似文献
237.
Esteban Acevedo‐Trejos Gunnar Brandt Agostino Merico S. Lan Smith 《Global Ecology and Biogeography》2013,22(9):1060-1070
238.
Three dehydrotetrapeptides of rationally varying structure were prepared and tested as affectors of cathepsin C. These compounds appeared to be substrates of the enzyme, being equipotent with their classical counterparts. Thus, replacement of amino acid in a short peptide by corresponding dehydroamino acid does not prevent cathepsin C in recognizing dehydropeptide as its substrate. 相似文献
239.
There persist two widely held but mutually inconsistent views on the evolution of post‐fertile lifespan of human females. The first, prevalent within anthropology, sees post‐fertile lifespan (PFLS) in the light of adaptive processes, focusing on the social and economic habits of humans that selected for a lengthy PFLS. 1 - 3 This view rests on the assumption that human PFLS is distinct from that of other species, and focuses on quantifying the selective causes and consequences of that difference. The second view, prevalent within gerontology and comparative biology, emphasizes that PFLS is a phylogenetically widespread trait 4 - 6 or that human PFLS is predictable based on life‐history allometries. 7 In this view, human PFLS is part of a broad cross‐species pattern and its genesis cannot, therefore, rely on human‐specific traits. Those who advocate the second view have questioned the “special pleading” for human specific explanations of PFLS, 4 and have argued that human PFLS is quantitatively greater but not qualitatively different than PFLS in many other animals. 5 , 8 Papers asking whether human PFLS is explained by the importance of mothers more than grandmothers, whether paternal or maternal grandparents have more of an effect on child survival, or who is providing the excess calories are associated with the first view that assumes the need to explain the existence of human PFLS on the basis of a uniquely human socioecology. Anthropologists largely see human PFLS as derived, while comparative gerontologists point to evidence that it is one instance of a ubiquitous cross‐species pattern. The two groups generally occupy non‐overlapping research circles, in terms of conferences and journals, and therefore interact little enough to largely avoid the need to reconcile their views, allowing the persistence of misconceptions in each field. Our goal is to identify and address the most important of these misconceptions and thereby make clear that both of these seemingly incongruent views contain valid points. We argue that two distinct but related traits have been lumped together under the same concept of “post‐reproductive lifespan,” one (post‐fertile viability) that is tremendously widespread and another (a post‐fertile life stage) that is derived to hominins, and that the differences and connections between these two traits are necessary for understanding human life‐history evolution. 相似文献
240.
Wasimuddin Sebastian Menke Jörg Melzheimer Susanne Thalwitzer Sonja Heinrich Bettina Wachter Simone Sommer 《Molecular ecology》2017,26(20):5515-5527
Although the significance of the gut microbiome for host health is well acknowledged, the impact of host traits and environmental factors on the interindividual variation of gut microbiomes of wildlife species is not well understood. Such information is essential; however, as changes in the composition of these microbial communities beyond the natural range might cause dysbiosis leading to increased susceptibility to infections. We examined the potential influence of sex, age, genetic relatedness, spatial tactics and the environment on the natural range of the gut microbiome diversity in free‐ranging Namibian cheetahs (Acinonyx jubatus). We further explored the impact of an altered diet and frequent contact with roaming dogs and cats on the occurrence of potential bacterial pathogens by comparing free‐ranging and captive individuals living under the same climatic conditions. Abundance patterns of particular bacterial genera differed between the sexes, and bacterial diversity and richness were higher in older (>3.5 years) than in younger individuals. In contrast, male spatial tactics, which probably influence host exposure to environmental bacteria, had no discernible effect on the gut microbiome. The profound resemblance of the gut microbiome of kin in contrast to nonkin suggests a predominant role of genetics in shaping bacterial community characteristics and functional similarities. We also detected various Operational Taxonomic Units (OTUs) assigned to potential pathogenic bacteria known to cause diseases in humans and wildlife species, such as Helicobacter spp., and Clostridium perfringens. Captive individuals did not differ in their microbial alpha diversity but exhibited higher abundances of OTUs related to potential pathogenic bacteria and shifts in disease‐associated functional pathways. Our study emphasizes the need to integrate ecological, genetic and pathogenic aspects to improve our comprehension of the main drivers of natural variation and shifts in gut microbial communities possibly affecting host health. This knowledge is essential for in situ and ex situ conservation management. 相似文献