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Columba livia is an important reservoir and carrier of Cryptococcus neoformans, Cryptococcus uniguttulatus, Cryptococcus laurentii and Cryptococcus albidus. Upper digestive tract of this species is also known as a habitat for Cryptococcus neoformans. Given the increasing clinical interest of this microorganism, 331 swabs from crop and 174 dropping samples from pigeon lofts in Grand Canary Island have been studied. The obtained results show an extensive presence samples 81 positive (24.47%) of Cryptococcus spp. in analysed crops: 32 (9.66%) for C. neoformans, 24 (7.2%) for C. uniguttulatus, 23 (6.9%) for C. albidus and 2 (0.6%) for C. laurentii. In the same way, Cryptococcus spp was also isolated in 82 (47.13%), dropping samples: C. neoformans in 59 (33.9%), C. uniguttulatus, in 9 (5.17%), C. laurentii in 8 (4.59%) and C. albidus in 6 (3.44%) of the investigated samples, respectively. The cryptococcosis produced by species of cryptococci other than C. neoformans has become more important during the last decade, supporting the study on the role of pigeon in the epidemiology of this disease.  相似文献   

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Related plants often produce seeds that are dispersed in very different ways, raising questions of how and why plants undergo adaptive shifts in key aspects of their reproductive ecology. Here we analyze the evolution of seed dispersal syndromes in an ancient group of plants. Ephedra (Gymnospermae; Gnetales; Ephedraceae) is a genus containing ≈50 species in semiarid ecosystems worldwide and with three distinct types of cones. We collected mature cones and seeds of ten species of Ephedra in southwestern United States and measured nine morphological traits for each species. Principal component analysis and other data characterized three types of Ephedra cones and seeds. Species with dry, winged cone bracts are dispersed by wind (i.e., E. torreyana and E. trifurca), those with succulent, brightly-colored cone bracts are dispersed by frugivorous birds (i.e., E. antisyphilitica), and those with small, dry cone bracts and large seeds are dispersed by seed-caching rodents (e.g., E. viridis and E. californica). Two species (E. funerea and E. nevadensis) have cone and seed morphologies intermediate between two seed dispersal syndromes. Seed and cones traits were mapped onto two recent phylogenies to help reveal the evolutionary history of seed dispersal syndromes. Bird dispersal is thought to be the ancestral form of seed dispersal in ephedras as it is common in the Old World where Ephedra originated, but the three North American species dispersed by birds are not monophyletic. The two wind dispersed species in North America also do not cluster together, suggesting separate origins. Seed dispersal by seed-caching rodents is common in North America and appears to have evolved several times, but this syndrome is absent form other continents. The evolutionary history of Ephedra in North America suggests that the means of seed dispersal has been malleable. Evolutionary shifts were likely linked to changes in ecological conditions.  相似文献   

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Interaction of Bdellovibrio bacteriovorus 100NCJB with bacteria Campylobacter jejuni (strains 1, 2, 3, 4, and 5) and Helicobacter pylori, strain TX30a, was confirmed. The results indicate that lytic activity of bdellovibrios both in liquid media and cells attached to a surface was observed. The potential use of the antimicrobial activity of predatory bacteria for environmental bioprotection and public health is discussed.  相似文献   

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We present data on the habitat, density, and spatial distribution of Rivulus giarettai, and discuss some biotic and abiotic variables related to its abundance in Free Flowing Waters (FFW) and Dam Reservoirs (DR) in palm grove (Mauritia flexuosa) marshes (Veredas) in Uberlandia, Minas Gerais, southeastern Brazil. The mean density (individuals/plot) of R. giarettai was about 13 times higher in FFW than in DR. In FFW, the density of R. giarettai was highest at intermediate amounts of substrate (plant mass) and it was positively rank-correlated with the depth, and the number of arthropods. Individuals occurred in an aggregated distribution. The aggregated pattern could be related to a concentration of individuals in microhabitats neither too much exposed nor completely saturated by plants. R. giarettai was relatively abundant and tolerant to slight man-made habitat modifications. Damming appeared to be especially problematic by negatively affecting its density.  相似文献   

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Phengaris (=Maculinea) arion is an endangered social parasite of Myrmica ants, and for a very long time was considered as specific to Myrmica sabuleti. Previous studies carried out in Poland suggested some discrepancies within this assumption, and therefore a much more intensive survey was undertaken. The host ant use of P. arion was studied at five sites in different types of biotopes in Poland, i.e. xerothermal grasslands where Thymus pulegioides was used as a larval food plant by the butterfly, and more or less sandy biotopes with Thymus serpyllum. Altogether nine Myrmica species were recorded, and considerable variation in species composition and density of nests was recorded. At four localities M. sabuleti proved to be the most common ant. A total of 529 Myrmica nests were examined, and only 20 of them contained larvae and pupae of P. arion. Host ants belonged to five different species, i.e. M. sabuleti, Myrmica scabrinodis, Myrmica schencki, Myrmica lobicornis and Myrmica hellenica. Only at one site (NE Poland) was a significant heterogeneity in parasitation rates among Myrmica species detected. M. lobicornis was the most often infested ant there, which may suggest local specialisation of the butterfly. Overall low parasitism rates may explain the vulnerability of P. arion in Central Europe but further studies are also necessary.  相似文献   

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Following a re-examination of the material treated under Barleria brevispina (Fiori) Hedrén in the recent Flora of Somalia account of the Acanthaceae, it is concluded that two distinct species are involved and Barleria compacta Malombe & I. Darbysh. is described here from north-eastern Somalia. Its affinities and conservation status are discussed.  相似文献   

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The salt tolerance of two representatives of genus Spirulina (Arthrospira) Spirulina platensis and Spirulina maxima has been investigated. They both are the wide-spread objects of photobiotechnology and it has been shown that the content of 5–15 % sea-water in medium has not caused the decreasing of biomass yield more than 15–20% as compared with control. The further decreasing of biomass was proportionate to sea-water content in medium. The investigation of reactivity of native (intravital) exometabolites secreted into cultural medium has showed that the sea-water content influence the oxidative activity (OA) of exometabolites and hour’s rhythmics.  相似文献   

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