963 resultados para Biological Species Concept


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The invasive thistle Carduus nutans has been reported to be allelopathic, yet no allelochemicals have been identified from the species. In a search for allelochemicals from C. nutans and the closely related invasive species C. acanthoides, bioassay-guided fractionation of roots and leaves of each species were conducted. Only dichloromethane extracts of the roots of both species contained a phytotoxin (aplotaxene, (Z,Z,Z)-heptadeca-1,8,11,14-tetraene) with sufficient total activity to potentially act as an allelochemical. Aplotaxene made up 0.44 % of the weight of greenhouse-grown C. acanthoides roots (ca. 20 mM in the plant) and was not found in leaves of either species. It inhibited growth of lettuce 50%(I-50) in soil at a concentration of ca. 0.5 mg g(-1) of dry soil (ca. 6.5 mM in soil moisture). These values gave a total activity in soil value (molar concentration in the plant divided by the molarity required for 50 % growth inhibition in soil = 3.08) similar to those of some established allelochemicals. The aplotaxene I-50 for duckweed (Lemna paucicostata) in nutrient solution was less than 0.333 mM, and the compound caused cellular leakage of cucumber cotyledon discs in darkness and light at similar concentrations. Soil in which C. acanthoides had grown contained aplotaxene at a lower concentration than necessary for biological activity in our short-term soil bioassays, but these levels might have activity over longer periods of time and might be an underestimate of concentrations in undisturbed and/or rhizosphere soil.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Neoparaphytoseius charapa n. sp. is described, based on the morphology of adult females and males collected on Inga edulis ( Mart.) ( Fabaceae) in northeastern Peru. Neoparaphytoseius Chant & McMurtry is redefined on the basis of the new species and re-examination of its type species N. sooretamus Chant & McMurtry.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Tributyltin exposure is the primary cause of imposex development in gastropods, making them excellent bioindicators. The present research represents the first examination of butyltin (BT) contamination in surface sediments associated with imposex in Leucozonia nassa and L. ocellata in a harbour complex area in Espirito Santo, southeastern Brazil. The objectives of this study were to evaluate the organotin pollution in the area and to assess the sensitivity of both species to BT pollution through imposex development. Specimens were collected between 2007 and 2010 and the sediments were sampled in 2007. Imposex intensity was evaluated based on the percentage of imposexed females, the relative penis length index (RPLI) and the average value of the vas deferens sequence index (VDSI). BTs were analysed using gas chromatography equipped with a pulsed flame photometric detector (PFPD). The results demonstrated the occurrence of elevated concentrations of BTs in the sediment ranging from 383.7 to 7172.9 ng Sn g(-1), indicating a severe contamination of the area, which was confirmed by the biological monitoring results. Our findings also indicated that L. ocellata is a less sensitive species than L. nassa and that this differential sensitivity plays a key role in the distributions of the populations of both species in the studied area.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Paracoccidioides lutzii, formerly known as 'Pb01-like' strains in the P. brasiliensis complex, is proposed as a new species based on phylogenetic and comparative genomics data, recombination analysis, and morphological characteristics. Conidia of P. lutzii are elongated, different from those of P. brasiliensis. P. lutzii occurs in the central and northern regions of Brazil. Studies comparing P. brasiliensis and P. lutzii may have significant clinical consequences for the diagnosis and treatment of paracoccidioidomycosis.

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Biological activities of flavonoids have been extensively reviewed in literature. The biochemical profile of afzelin, kaempferitrin, and pterogynoside acting on reactive oxygen species was investigated in this paper. The flavonoids were able to act as scavengers of the superoxide anion, hypochlorous acid and taurine chloramine. Although flavonoids are naturally occurring substances in plants which antioxidant activities have been widely advertised as beneficial, afzelin, kaempferitrin, and pterogynoside were able to promote cytotoxic effect. In red blood cells this toxicity was enhanced, depending on flavonoids concentration, in the presence of hypochlorous acid, but reduced in the presence of 2,20 -azo-bis(2-amidinopropane) free radical. These flavonoids had also promoted the death of neutrophils, which was exacerbated when the oxidative burst was initiated by phorbol miristate acetate. Therefore, despite their well-known scavenging action toward free radicals and oxidants, these compounds could be very harmful to living organisms through their action over erythrocytes and neutrophils.

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The comparison between linguistic change and biologic evolution is a subject that has caused and still causes much controversy among linguists and other academics that see, in this parallel, problems related to similar attempts in the nineteenth century by Social Darwinism, which approached the biological evolution with social and cultural development of a people. However, this paper aims to show that today this parallel is not built in the same way as was done before. Names like William Labov, Salikoko Mufwene, Jonathan West and Hildo Honorio do Couto in linguistics; Charles Darwin in biology; and Tom Ingold and Clifford Geertz in anthropology, showed that areas of Humanities, such as linguistics and anthropology, and of Biological Sciences, as phylogeny and genetics, are likely to be worked together by the great similarities between processes that compose them. Thus, based on the writings of these authors and some others, this paper presents this theme’s controversy; it shows the similarities between characteristics of languages and species; it seeks through the concepts MA Mental, MA Social and MA Natural of the languages (coined by Couto on Linguística, ecologia e ecolinguística: contato de línguas) to develop ideas of how it is possible to think the language change in the light of Darwin's concept, Natural Selection; and finally, it shows that the parallel theme is rather productive, based on the texts and discussions presented in the whole paper, and that the controversy has been being dissolved with more and more people working on the parallel between language and species