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51.
Local-scale heterogeneity in the spatial distribution of soil nutrients promotes a suite of physiological and morphological responses in plants. These responses influence the competitive ability of plants within communities and potentially plant primary productivity. There is a growing appreciation then for the need to study factors that may modulate these plant responses to soil nutrient heterogeneity. Soil fauna are potentially one such modulating factor. For example, through impacts on organic matter decomposition and distribution they may directly modify nutrient patches and therefore the stimulus plants are responding to. In addition they may modify plant root mass and architecture through processes such as herbivory, potentially altering the outcome of a plant's response to a nutrient patch. Using grassland microcosms, consisting of a multi-species plant assemblage, multiple soil horizons and a speciose soil biota, we tested whether soil faunal assemblage composition might modulate plant responses to nutrient patches represented by litterbags. We show that root proliferation into a nutrient patch, a variable which is positively related to a plant's success under conditions of interspecific competition in a nutrient-limited environment, is reduced by the presence of mesofauna, and even more so by the presence of mesofauna together with macrofauna. Reductions in this proliferation response when mesofauna were present without macrofauna appeared to be a function of reduced root density. When macrofauna were included, reduced root density, and higher rates of litter patch disappearance, together contributed to the reduction in proliferation but additional mechanisms must also have played a role. Our results suggest that the effects and interactions generated by soil fauna need to be explicitly considered in analyses of how plants forage for nutrients in a patchy environment.  相似文献   
52.
Primary lymphoedema refers to a swelling of a part or parts of the body due to a congenital defect in the lymphatic system. Recently, the patent blue violet dye test has been described as a means of confirming the diagnosis in dogs. This case report demonstrates that the dye test is a simple and useful diagnostic test for the diagnosis of primary lymphoedema In the cat also.  相似文献   
53.
This study presents a global analysis of forest cover and forest protection. An updated Global Forest Map (using MODIS2005) provided a current assessment of forest cover within 20 natural forest types. This map was overlaid onto WWF realms and ecoregions to gain additional biogeographic information on forest distribution. Using the 2008 World Database on Protected Areas, percentage forest cover protection was calculated globally, within forest types, realms and ecoregions, and within selected areas of global conservation importance. At the 10% tree cover threshold, global forest cover was 39 million km2. Of this, 7.7% fell within protected areas under IUCN management categories I–IV. With the inclusion of IUCN categories V and VI, the level of global forest protection increased to 13.5%. Percentage forest protection (IUCN I–IV) varied greatly between realms from 5.5% (Palearctic) to 13.4% (Australasia), and for forest types from 3.2% (temperate freshwater swamp forest) to 28% (temperate broadleaf evergreen forest). Median protection of forest cover in 670 ecoregions (forest above a specified threshold) was 5.9% (IUCN I–IV); at IUCN I–VI, 46% of the ecoregions had less than 10% forest protection. Considering their biodiversity importance, forest protection within global priority areas was insufficient, e.g., median protection of 8.4% in biodiversity hotspots (IUCN I–IV). Results have policy relevance in terms of the target of the Convention on Biological Diversity (CBD), reconfirmed in 2008, to effectively conserve “at least 10% of each of the world’s forest types”. Regular updates of these analyses would allow progress towards achieving that target to be monitored.  相似文献   
54.
An 8-year-old male Belgian Malinois was referred for evaluation of progressive caudal paresis of 2 to 3 weeks' duration. Radiography revealed a mottled appearance to the body of L4 and misshapen intervertebral foramen at L4-L5. Myelography revealed that the dye column terminated within the body of L4. Computed tomography revealed a soft tissue mass adjacent to or involving the spinal cord and L4, with complete destruction of a portion of the floor of the vertebral foramen. Small circular lesions were also noticed within the body of L3 and L5. A left-sided hemilaminectomy was performed. Histologic examination of a biopsy specimen revealed a high-grade sarcoma. Because of the poor prognosis, the dog was euthanatized. Necropsy examination revealed osteosarcoma, with lesions in L3 to L7, the sacrum, and the lungs. Metastatic lesions in adjacent bones have been termed skip metastases and the primary tumor is typically in long bones. Prognosis associated with skip metastases is similar to or even graver than that associated with pulmonary metastases. In the dog of the present report, the unusual finding of distinct foci of osteosarcoma within 5 adjacent lumbar vertebrae and the sacrum was consistent with skip metastases, potentially spread via the vertebral venous plexus.  相似文献   
55.
The effect of the antiseptic povidone-iodine (P-I) on neutrophil locomotion was tested in vitro. Neutrophil migration into Micropore filters was significantly stimulated by P-I at concentrations between 0.03% and 0.005%. At higher concentrations (greater than or equal to 0.05%), a dose-dependent inhibition of neutrophil migration could be observed which was due to cytotoxic effects of P-I as shown by pyknosis and cell lysis. To analyze these effects, 2 components of P-I (namely, povidone and iodide) were tested separately. In these tests, povidone induced a pronounced stimulation of neutrophil migration at concentrations similar to the stimulatory concentrations of P-I. Inhibition of neutrophil migration or cytotoxic effects of povidone was not observed, even when tested at high concentrations (5.0%). Iodide (as NaI or KI) was cytotoxic and strongly inhibited neutrophil migration when it was tested at concentrations greater than that likely to be present in the inhibitory concentrations of P-I. Stimulatory effects of iodide on neutrophil migration could not be observed when tested over a wide range of noncytotoxic concentrations. Free iodine was not tested, but was considered to be the toxic component by exclusion. The patterns of response were similar for neutrophils from the 4 species tested. Migration of rabbit neutrophils, however, was inconsistently and weakly stimulated by P-I or povidone. These data indicate that the widely used antiseptic P-I, depending on its concentration, can either stimulate or inhibit neutrophil migration.  相似文献   
56.
Placentomes were romoved from 4 to 6 cows before/after treatment with dexamethasone (DXMS) at days 200/205, 220/225, and 250/255 of pregnancy. Preparations of cotyledonary tissue were first perfused with plain HEPES buffered medium 199 (rinsing fraction), followed by the addition of either 3H-androstenedione and 3H-pregnenolone or unlabelled cholesterol and pregnenolone as substrates. As indicated by examining the rinsing fractions from untreted animals estrone concentrations. (output) increased from day 200 to day 250 of pregnancy, treatment with DXMS led to a further significant increase on all days examined. Concomitantly with this increase a decrease in pregnenolone and progesterone was observed. Distinct effects of substrate additon were limited to the transformation of 3H-pregnenolone into 3H-testosterone/epitestosterone (yield ˜ 8%), furtheron the addition of unlabelled pregnenolone (but not of cholesterol), significantly increased progesterone synthesis as determined by radio immunoassay. Neither these nor other results published till now account for the high estrogen production by the bovine placenta on in vivo conditions. It is concluded that the in vitro systems used so far not or only in part reflect the in vivo conditions necessary to allow complete expression of the steroidogenic capacity of the bovine trophoblast .  相似文献   
57.
Natalie Netz  Till Opatz 《Marine drugs》2015,13(8):4814-4914
Marine indole alkaloids comprise a large and steadily growing group of secondary metabolites. Their diverse biological activities make many compounds of this class attractive starting points for pharmaceutical development. Several marine-derived indoles were found to possess cytotoxic, antineoplastic, antibacterial and antimicrobial activities, in addition to the action on human enzymes and receptors. The newly isolated indole alkaloids of marine origin since the last comprehensive review in 2003 are reported, and biological aspects will be discussed.  相似文献   
58.
The switch from spring-sown to autumn-sown cereals and the loss of habitat heterogeneity are often suggested to be key drivers of breeding bird decline on arable farmland. Yet, both factors are interlinked and it remains uncertain whether autumn-sown cereals reduce breeding bird numbers also in the structurally complex arable farmland of northern Europe. We tested whether autumn-sowing of cereals at both local and landscape scales affected the breeding bird community in a heterogeneous agricultural landscape of south-central Sweden. Rotation between sowing types was used as a semi-experiment based on 34 spring- vs. 41 autumn-sown cereal plots centred on infield non-crop islands of similar structure, size and surroundings. Species richness and territory abundance of ground-foraging species were significantly lower in autumn- than in spring-sown cereal plots both in the crop fields and the infield non-crop islands during the breeding season. No such effect was observed among foliage gleaning birds. Species richness in spring-sown cereal plots was less the more autumn-sown crops in the surrounding landscape within a 500 m radius. Average skylark densities did not differ between autumn- and spring-sown cereal plots because habitat preferences changed; densities declined in autumn-sown cereals during the growing season whereas they increased on spring-sown fields which had shorter swards throughout the breeding season. Our results indicate that negative effects of autumn-sown crops on breeding bird numbers spill over into both neighbouring non-crop and crop habitats. We conclude that agri-environmental schemes should place more emphasis on facilitating the value of the cropped area of fields as a foraging and nesting habitat. The retention of various non-crop habitats alone may not provide sufficient food close to nest sites for farmland birds that rely on crop fields for foraging.  相似文献   
59.
ABSTRACT: A mysterious disease affecting calves, named bovine neonatal pancytopenia (BNP), emerged in 2007 in several European countries. Epidemiological studies revealed a connection between BNP and vaccination with an inactivated vaccine against bovine virus diarrhea (BVD). Alloantibodies reacting with blood leukocytes of calves were detected in serum and colostrum of dams, which have given birth to calves affected by BNP. To understand the linkage between vaccination and the development of alloantibodies, we determined the antigens reacting with these alloantibodies. Immunoprecipitation of surface proteins from bovine leukocytes and kidney cells using sera from dams with a confirmed case of BNP in their gestation history reacted with two dominant protein species of 44 and 12 kDa. These proteins were not detected by sera from dams, free of BVDV and not vaccinated against BVD, and from sera of animals vaccinated with a different inactivated BVD vaccine. The 44 kDa protein was identified by mass spectrometry analysis as MHC I, the other as β-2-microglobulin. The presence of major histocompatibility complex class I (MHC I) in the vaccine was confirmed by Western blot using a MHC I specific monoclonal antibody. A model of BNP pathogenesis is proposed.  相似文献   
60.
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