198 resultados para LUMBRICUS-TERRESTRIS
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Kartta kuuluu A. E. Nordenskiöldin kokoelmaan
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Kartta kuuluu A. E. Nordenskiöldin kokoelmaan
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Pallonpuoliskot halkaisijaltaan n. 26 cm.
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Invokaatio: D.D.
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No unequivocal evidence exists of genetically inherited resistance to metals/metalloids in field populations of earthworms. We studied cocoon production in adult Lumbricus rubellus Hoffmeister collected from an abandoned arsenic and copper mine (Devon Great Consols, Devon, UK), and abandoned tungsten mine (Carrock Fell, Cumbria, UK) and an uncontaminated cultured population. The earthworms were kept in uncontaminated soil for nine weeks. From a total of 42 L. rubellus from each site, Devon Great Consols adults produced 301 cocoons, of which 42 were viable; Carrock Fell 60 cocoons, of which 11 were viable; and the reference population 101 cocoons, of which 62 were viable. The hatchlings were collected and stored at 4degreesC at weekly intervals. After 12 weeks, all hatchlings were transferred to clean soil and maintained at 15degreesC for 20 weeks until they showed evidence of a clitellum. In toxicity trials, F1 generation L. rubellus were exposed to 2,000 mg As/kg as sodium arsenate or 300 mg Cu/kg as copper chloride for 28 d. The F1 generation L. rubellus from Devon Great Consols mine demonstrated resistance to arsenate but not copper. All L. rubellus from Devon Great Consols kept in soil treated with sodium arsenate remained in good condition over the 28-d period but lost condition rapidly and suffered high mortality in soil treated with copper chloride. The control population suffered high mortality in soil treated with sodium arsenate and copper chloride. Previous work has shown that field-collected adults demonstrate resistance to both arsenate and Cu toxicity under these conditions. Thus, while arsenate resistance may be demonstrated in F1 generation L. rubellus from one of the contaminated sites, Cu resistance is not. The F1 adults and F2 cocoons did not have significantly higher levels of As than the control population, with no residual As tissue burden, suggesting that resistance to As in these populations may be inherited.
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Subcellular fractionation techniques were used to describe temporal changes (at intervals from T0 to T70 days) in the Pb, Zn and P partitioning profiles of Lumbricus rubellus populations from one calcareous (MDH) and one acidic (MCS) geographically isolated Pb/Zn-mine sites and one reference site (CPF). MDH and MCS individuals were laboratory maintained on their native field soils; CPF worms were exposed to both MDH and MCS soils. Site-specific differences in metal partitioning were found: notably, the putatively metal-adapted populations, MDH and MCS, preferentially partitioned higher proportions of their accumulated tissue metal burdens into insoluble CaPO4-rich organelles compared with naive counterparts, CPF. Thus, it is plausible that efficient metal immobilization is a phenotypic trait characterising metal tolerant ecotypes. Mitochondrial cytochrome oxidase II (COII) genotyping revealed that the populations indigenous to mine and reference soils belong to distinct genetic lineages, differentiated by 13%, with 7 haplotypes within the reference site lineage but fewer (3 and 4, respectively) in the lineage common to the two mine sites. Collectively, these observations raise the possibility that site-related genotype differences could influence the toxico-availability of metals and, thus, represent a potential confounding variable in field-based eco-toxicological assessments.
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A RPPN SESC-Pantanal, em Barão de Melgaço, MT, apresenta características em grande parte associadas à fisionomia do cerrado, com áreas mais secas em relação às regiões localizadas mais ao sul e a oeste do Pantanal. O mapa de cobertura do solo, produzido através de classificação não-supervisionada de imagens de satélite, identificou 18 classes de cobertura e nove domínios fisionômicos, que correspondem a uma representação sintética da distribuição das unidades da paisagem na Reserva. O desenvolvimento apropriado de estratégias de manejo e de conservação fundamenta-se principalmente no conhecimento da fauna regional, ressaltado pela sua abundância e formas de uso da área. A anta, Tapirus terrestris, e o cervo-do-pantanal, Blastocerus dichotomus, são elementos bastante comuns na paisagem da RPPN. A estimativa do tamanho da população de antas na região de estudo foi de 581 indivíduos; a densidade (0,71 ind./km2), no conjunto das fisionomias florestais da região, foi 92% mais elevada do que para as formações campestres (0,37 ind./km2). O tamanho populacional estimado para o cervo-do-pantanal foi de 135 indivíduos (0,44 ind./km2) para o período seco, e 157 indivíduos (0,73 ind./km2) para o período úmido. Com base nos modelos de distribuição gerados, nos resultados obtidos via o Índice de Seleção e nas estimativas de densidade, pode-se inferir sobre a qualidade dos hábitats para as espécies. As Matas com Acuri (Scheelea phalerata) são de elevada importância para T. terrestris, embora a espécie tenha ampla distribuição na Reserva. B. dichotomus tem sua maior população no Pantanal e, na Reserva, está em condição peculiar em relação à descrita como característica para a espécie: ocupa hábitats mais secos do que na maior parte de sua área de ocorrência Os hábitats campestres, relacionados à presença de murundus, foram selecionados positivamente pela espécie. A análise espacial em diferentes escalas foi fundamental para evidenciar a importância de corpos d’água (tanques ou baías) na previsão da ocorrência da espécie: as zonas de maior probabilidade dispõem-se na forma de núcleos centrados na rede de tanques, na área central da Reserva e nas adjacências de baías na porção leste da UC. As análises demonstraram uma hierarquia no uso dos hábitats, tanto para T. terrestris quanto para B. dichotomus, permitindo identificar zonas onde as chances são maiores de ocorrência das espécies, uma expressão de conjuntos de fatores que devem se aproximar do ótimo para as espécies no contexto da paisagem estudada.
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The Dufour's gland is found closely associated with the sting apparatus of all female hymenopterans, playing multiple roles among bees. In some species of Bombus the gland may be involved in production of nestmate recognition pheromones, but in B. terrestris its function is not certain yet. The morphology of the :Dufour's gland of B. terrestris queens and the ultrastructural features of its cells were studied in different ages and behavioural stages using routine transmission electron microscopy. Measurements of the length and the diameter of the gland in the same conditions were also made. The Dufour's gland of the queen increases significantly in size (both in length and in diameter) with age and reproductive activity the ultrastructural features of the gland show electrondense material that comes from the haemolymph. This material is also present in the intercellular spaces, and is conducted to the subcuticular space, to be released directly into the glandular lumen. Hence at least part of the secretion is probably taken up directly from the haemolymph. The ultrastructural features indicate a more active phase of the gland corresponding to the period of egg-laying of the queen, and a decrease in activity when the queen is in hibernation as well as after the competition point. In conclusion, the gland is probably involved in reproduction, more specifically, in the marking off eggs.
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The Dufour's gland of Bombus terrestris workers, of different ages and with varying degrees of ovary development, was studied with the aim to verify its involvement in reproduction. Measurements of the diameter and the length of the gland were made using an ocular micrometer adapted to a microscope. Transmission electron microscopy was used to study the morphology of the secretory cells and to analyze the secretory cycle. The glandular cells were considered to be near type II cells of NOIROT and QUENNEDEY (1974), a type that has not been described before in Hymenopterans. The results show that there is a correlation between the degree of ovary development and Dufour's gland activity of workers. The diameter of the gland and the secretory cell activity increased with increasing oocyte size in the ovary. Regressive conditions of the gland were observed, which are probably related to increasing worker age. To elucidate the production and releasing process of the secretion and to establish its precise function, a comparative analysis of the secretion process of the Dufour's gland of queens and workers is needed.
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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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O tapir ou anta, descrito como o maior mamífero terrestre brasileiro, pertence à ordem Perissodactila, subordem Hippomorfa, superfamília Tapiroidea e família Tapiridae. Na floresta úmida está envolvido com a dispersão de sementes em função das características do tubo digestivo. O acompanhamento do ciclo estral permite avaliar e compreender a atividade reprodutiva nas espécies animais. Nos animais silvestres, o estresse da contenção pode interferir na própria ciclicidade gonadal, uma das alternativas é o acompanhamento dos hormônios gonadais nas excretas. Buscamos neste trabalho o acompanhamento periódico da atividade gonadal através da quantificação de progesterona no leite. Utilizamos uma fêmea recém-parida no Zoológico de Araçatuba, da qual colhemos leite, esfregaço vaginal e temperatura retal. A progesterona foi quantificada por radioimunoensaio de fase sólida (Coat-a-Count, DPC®) com curva padrão fornecida pela F.A.O. O ensaio mostrou sensibilidade de 1,25 nmol/l com coeficiente de variação intra-ensaio de 15,36%. Durante a fase de lactação, a fêmea não apresentou níveis detectáveis de progesterona por 158 dias (de novembro a abril). O primeiro pico de produção foi de 2,3 nmol/l e apresentou duração de 5 dias. O segundo pico de 3,54 nmol/l teve uma duração de 23 dias. Setenta e quatro dias após o aparecimento da progesterona no leite a lactação cessou. Podemos concluir que a fêmea de tapir apresentou um período de anestro lactacional de aproximadamente 5 meses e voltou a ciclar no outono (abril) sugerindo pouca influência do fotoperíodo. A quantificação da progesterona no leite mostrou-se útil para o acompanhamento do ciclo estral na espécie, porém a variação da citologia vaginal e temperatura retal não apresentaram correlação com os níveis hormonais.
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The phylogenetic relationship of the notosuchians Mariliasuchus amarali (Campanian; Bauru Group) and Notosuchus terrestris (Santonian; Neuquen Group) is revised. Morpho-anatomical evaluation of Mariliasuchus in the current bibliography indicate close relationship with Notosuchus, while cladistic analysis either related Mariliasuchus to Candidodon itapecuruense (Albian/eo-Cenomanian; Sao Luis-Grajau Basin), as part of the phylotaxon Candidodontidae, or to Comahuesuchus brachybuccalis (Santonian; Neuquen Group). Comparative study of specimens shows similarities on the palate, choanae, dentition, retroarticular process, and other structures from Mariliasuchus and Notosuchus supporting the original classification as a Notosuchidae. Preliminary phylogenetic analysis sets these taxa as sister-groups. Reevaluation of a previously published phylogenetic analysis from other authors provides further support for the Mariliasuchus + Notosuchus clade. The current work indicates that Mariliasuchus is a Notosuchidae, refuting its allocation as a Candidodontidae. The influence of character construction and the definition of Notosuchia are discussed.
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A 55-year-old man was attacked by a Brazilian tapir (Tapirus terrestris) after surprising and stabbing the animal in his corn plantation. The victim received deep bites in the thighs, neck, and cervical areas, resulting in severe hemorrhage and death. This is the first report of a tapir incident resulting in death and is of interest because of the severity of the contusions and lacerations caused by the provoked animal.