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71.
72.
Current levels of endangerment and historical trends of species and habitats are the main criteria used to direct conservation efforts globally. Estimates of future declines, which might indicate different priorities than past declines, have been limited by the lack of appropriate data and models. Given that much of conservation is about anticipating and responding to future threats, our inability to look forward at a global scale has been a major constraint on effective action. Here, we assess the geography and extent of projected future changes in suitable habitat for terrestrial mammals within their present ranges. We used a global earth-system model, IMAGE, coupled with fine-scale habitat suitability models and parametrized according to four global scenarios of human development. We identified the most affected countries by 2050 for each scenario, assuming that no additional conservation actions other than those described in the scenarios take place. We found that, with some exceptions, most of the countries with the largest predicted losses of suitable habitat for mammals are in Africa and the Americas. African and North American countries were also predicted to host the most species with large proportional global declines. Most of the countries we identified as future hotspots of terrestrial mammal loss have little or no overlap with the present global conservation priorities, thus confirming the need for forward-looking analyses in conservation priority setting. The expected growth in human populations and consumption in hotspots of future mammal loss mean that local conservation actions such as protected areas might not be sufficient to mitigate losses. Other policies, directed towards the root causes of biodiversity loss, are required, both in Africa and other parts of the world.  相似文献   
73.
The aim of this work was to use in vivo models to evaluate the analgesic and anti-inflammatory activities of ursolic acid (UA) and oleanoic acid (OA), the major compounds isolated as an isomeric mixture from the crude methylene chloride extract of Miconia albicans aerial parts in an attempt to clarify if these compounds are responsible for the analgesic properties displayed by this plant. Ursolic acid inhibited abdominal constriction in a dose-dependent manner, and the result obtained at a content of 40 mg kg(-1) was similar to that produced by administration of acetylsalicylic acid at a content of 100 mg kg(-1). Both acids reduced the number of paw licks in the second phase of the formalin test, and both of them displayed a significant anti-inflammatory effect at a content of 40 mg kg(-1). It is noteworthy that the administration of the isolated mixture, containing 65% ursolic acid/35% oleanolic acid, did not display significant analgesic and anti-inflammatory activities. On the basis of the obtained results, considering that the mixture of UA and OA was poorly active, it is suggested that other compounds, rather than UA and OA, should be responsible for the evaluated activities in the crude extract, since the crude extract samples displayed good activities.  相似文献   
74.
Nitroxyl (HNO) exhibits unique pharmacological properties that often oppose those of nitric oxide (NO), in part due to differences in reactivity toward thiols. Prior investigations suggested that the end products arising from the association of HNO with thiols were condition-dependent, but were inconclusive as to product identity. We therefore used HPLC techniques to examine the chemistry of HNO with glutathione (GSH) in detail. Under biological conditions, exposure to HNO donors converted GSH to both the sulfinamide [GSONH2] and the oxidized thiol (GSSG). Higher thiol concentrations generally favored a higher GSSG ratio, suggesting that the products resulted from competitive consumption of a single intermediate (GSNHOH). Formation of GSONH2 was not observed with other nitrogen oxides (NO, N2O3, NO2, or ONOO(-)),indicating that it is a unique product of the reaction of HNO with thiols. The HPLC assay was able to detect submicromolar concentrations of GSONH2. Detection of GSONH2 was then used as a marker for HNO production from several proposed biological pathways, including thiol-mediated decomposition of S-nitrosothiols and peroxidase-driven oxidation of hydroxylamine (an end product of the reaction between GSH and HNO) and NG-hydroxy-l-arginine (an NO synthase intermediate). These data indicate that free HNO can be biosynthesized and thus may function as an endogenous signaling agent that is regulated by GSH content.  相似文献   
75.
Histidine-containing peptide fragments of prion protein are efficient ligands to bind various transition metal ions and they have high selectivity in metal binding. The metal ion affinity follows the order: Pd(II)>Cu(II)>Ni(II)Zn(II)>Cd(II) approximately Co(II)>Mn(II). The high selectivity of metal binding is connected to the involvement of both imidazole and amide nitrogen atoms in metal binding for Pd(II), Cu(II) and Ni(II), while only the monodentate N(im)-coordination is possible with the other metal ions. The stoichiometry and binding mode of palladium(II) complexes show great variety depending on the metal ion to ligand ratio, pH and especially the presence of coordinating donor atoms in the side chains of peptide fragments. It is also clear from our data that the peptide fragments containing histidine outside the octarepeat (His96, His111 and His187) are more efficient ligands than the monomer peptide fragments of the octarepeat domain.  相似文献   
76.
A new population of the invasive American Eastern grey squirrel (Sciurus carolinensis) has recently settled in central Italy from an accidental release in Perugia, Umbria in the early 2000s. The grey squirrel is known to compete with and exclude native red squirrels (S. vulgaris) in the British Isles and Northern Italy, so it represents a potentially important new conservation threat to the red squirrel subspecies of south and central Italy, S. vulgaris italicus and S. v. meridionalis, which are endemic to peninsular Italy. The grey squirrel population range in Perugia is currently expanding at a rate of about 0.29 km/year (SD 0.19), slower than grey squirrel invasions elsewhere in Europe. Nuclear DNA analysed at 12 different microsatellite loci revealed that the grey squirrels in Perugia have extremely low genetic diversity, consistent with a small founder size. Genetic assignment tests indicate that the Perugia population was founded by translocations from an established population in Piedmont, Italy. No genetic substructure is evident yet in the Perugia population. These results together have serious consequences for the management of the grey squirrel invasion in Perugia and the conservation of the red squirrel subspecies: the Perugia grey squirrel population should be eradicated if politically feasible; otherwise new releases of grey squirrels, especially from sources other than the Piedmont population, should be prevented because such introductions could increase genetic diversity, thereby potentially increasing population range expansion rate to the much higher levels seen for more diverse grey squirrel populations elsewhere in Europe.  相似文献   
77.
Da Silva Cortinhas, M. C., Glienke, C., Prioli, A. J., Noleto, R. B., Matoso, D. A. and Cestari, M. M. 2010. A prime inference on genetic diversity (RAPDs) in the marine fish Atherinella brasiliensis (Teleostei, Atherinopsidae) from Southern Brazil. —Acta Zoologica (Stockholm) 91 : 242–248 As a result of the importance of Atherinella brasiliensis in estuarine environments, random amplified polymorphic DNA (RAPD) markers were used to verify the genetic diversity in A. brasiliensis from two different places in Paranaguá Bay (Paraná State) and one from the Conceição Lagoon (Santa Catarina State). Cytogenetic data have shown a high karyotypic diversity in some populations, although in others this peculiarity demonstrates rearrangements such as heterochromatinization. In the present study, a low level of genetic structuring between the samples from Conceição Lagoon compared with the others was observed through principal coordinate analysis (PCO), analysis of molecular variance and Mantel test according to 79 RAPD markers. As this specie does not perform horizontal migration and the individuals of Conceição Lagoon are isolated, three hypotheses are proposed to explain the results: (i) similar environments may show homogeneous populations not depending on the geographical distance, (ii) because vicariant events that formed the bays occurred in a recent period, the fragmentation effects over the structuring of the genetic diversity may still be low and not totally detectable by the RAPD technique and (iii) the isolation time or the number of generations may not be enough to promote a possible differentiation and genetic structuring between the specimens of these three places. The specimens of these places present a low level of differentiation and genetic structuring so we can consider them as a unique homogeneous population.  相似文献   
78.
Apple replant disease (ARD) is a soil-borne disease complex that affects young apple trees in replanted orchards, resulting in stunted growth and reduced yields. Newly developed rootstock genotypes with tolerance to ARD may help to control this disease. We determined the effects of rootstock genotype rotations during orchard renovation, by investigating root-zone soil microbial consortia and the relative severity of ARD on seven rootstock genotypes (M.9, M.26, G.30, G.41, G.65, G.935, and CG.6210) planted in soil where trees on four of those same rootstocks (M.9, M.26, G.30 and CG.6210) had grown for the previous 15 years. Rootstock genotyping indicated that genetic distances among rootstocks were loosely correlated with their differential responses to ARD. Root-zone fungal and bacterial community composition, assessed by DNA fingerprinting (T-RFLP), differed between M.26 and CG.6210. Soil bacterial communities were influenced most by which rootstock had grown in the soil previously, while fungal communities were influenced more by the current replanted rootstock. In a clone library of bacteria from M.26 and CG.6210 root-zone soil, β-Proteobacteria was the most abundant phylum (25% of sequences). Sequences representing the Burkholderia cepacia complex were obtained only from CG.6210 soil. Rootstock genotypes that were grown in the orchard soil previously affected subsequent ARD severity, but replanting with the same or closely related rootstocks did not necessarily exacerbate this disease problem. Our results suggest that genotype-specific interactions with soil microbial consortia are linked with apple rootstock tolerance or susceptibility to ARD.  相似文献   
79.
80.
New analysis has been carried out concerning the palaeoenvironmental reconstruction of some Italian sites dating from the Middle Pleistocene to the Bronze Age. Different aspects have been investigated on each site considering the data collected. The following sites have been analyzed: Isernia La Pineta (Molise); Visogliano and Caverna degli Orsi (Tieste); Toirano Caves (Liguria); Grotta Paglicci (Gargano); Riparo del Molare (Salerno); Grotta del Cavallo (Lecce); Castellaro Lagusello (Monzambano, Mantova).  相似文献   
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