150 resultados para Mucor hiemalis


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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

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Pós-graduação em Ciências Biológicas (Zoologia) - IBB

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O objetivo do presente estudo foi realizar o inventário da anurofauna, assim como investigar a distribuição espacial, temporal e a abundância relativa das espécies localizadas em um mosaico vegetacional na região de Botucatu, SP (22 º55’ 23’’S e 45 º27’ 28’’W). A área estudada situa-se na Escola do Meio Ambiente, possui aproximadamente 12 hectares e uma grande heterogeneidade de habitats. Os dados foram obtidos entre outubro de 2006 a outubro de 2007 e entre setembro de 2009 e setembro de 2010, totalizando 29 dias de campo. Os métodos utilizados foram busca ativa e armadilhas de interceptação e queda. Foram identificadas 26 espécies de anfíbios de cinco famílias: Bufonidae (2 sp), Hylidae (15), Leptodactylidae (6), Leiuperidae (2) e Microhylidae (1), distribuídas em três grandes áreas: área aberta, mata e borda de mata. Os ambientes de área aberta foram utilizados pela maioria dos anfíbios (n=21), enquanto a borda de mata apresentou a menor riqueza (n=5). Treze espécies foram observadas na mata. As espécies Physalaemus cuvieri, e Leptodacylus furnarius foram as mais generalistas, sendo encontradas em seis e cinco dos sete ambientes estudados, respectivamente. Entre as espécies estudadas, Leptodactylus bokermanni, foi a única registrada em apenas um dos ambientes (borda da mata). As espécies mais abundantes na comunidade foram Dendropsophus nanus representando 13%, seguida de Dendropsophus sanborni e Scinax fuscomarginatus ambas com 12 % dos indivíduos. As menos abundantes foram: Rhinella icterica, Leptodactylus mystacinus e Eupemphix nattereri onde cada uma contribuiu com 0,2% dos indivíduos registrados. A grande maioria das espécies foi registrada no período quente e chuvoso (setembro a março), com exceção da espécie Scinax hiemalis que esteve presente na época fria e seca. Já Hypsiboas ...(Resumo completo, clicar acesso eletrônico abaixo)

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A musculatura peitoral de anuros gera a potência necessária para a produção das vocalizações, tendo seu perfil histológico descrito para apenas uma espécie. Para esta, a musculatura peitoral apresenta 100% de fibras oxidativas rápidas. Entretanto, a taxa de vocalização apresenta enorme variação interespecífica, mesmo considerando espécies pertencentes a um mesmo gênero, como é o caso do gênero Scinax. Acreditamos que o perfil morfológico e histoquímico da musculatura peitoral, particularmente no tocante à capacidade oxidativa aeróbia, deve covariar com o desempenho aeróbio. Desta forma, o objetivo deste projeto foi realizar uma análise comparativa da morfologia e histoquímica do músculo peitoral de três diferentes espécies de pererecas do gênero Scinax. Os animais foram coletados durante o pico de atividade reprodutiva. Estes foram pesados e eutanaziados para a retirada dos músculos peitorais. Fragmentos musculares foram congelados em nitrogênio líquido e armazenados em freezer -80°C. Cortes histológicos (10μm), obtidos em criostato, foram submetidos à coloração HE (Hematoxilina-Eosina) para avaliação do padrão morfológico das fibras, e NADH-TR (Nicotinamida Adenina Dinucleotídeo-Tetrazólico Redutase), para avaliação do metabolismo oxidativo das fibras. Não houve diferenças qualitativas e quantitativas na morfologia e área das fibras entre as espécies. Provavelmente as diferenças comportamentais interespecíficas devem estar associadas a caracteres ultraestruturais da musculatura como capilarização, volume mitocondrial e tipo de miosina (MHC) presente na fibra muscular. O músculo peitoral de S. perereca e S. fuscovarius apresentou forte reação NADH-TR, o que demonstra alto metabolismo oxidativo, enquanto que Scinax hiemalis apresentou uma população de fibras com metabolismo oxidativo mais moderado; isso está de acordo com dados... (Resumo completo, clicar acesso eletrônico abaixo)

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A strain of a colorless, filamentous bacterium (tentatively identified as Leucothrix mucor) heavily infests the brine shrimp, Artemia salina. Its ultrastructure, unlike that of some other strains, does not reveal a distinct middle layer between its outer cell wall layer and cytoplasmic membrane, irregular blebs extending from the cell layers, or an external sheath. An entire infestation, represented as a mat of the bacterium with associated debris and microorganisms, sloughs from the shrimp when exposed to a variety of treatments. Primarily because most effective treatments are toxic to the shrimp, 100 ppm terramycin provides the treatment of choice.

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Nine marine fungi (Aspergillus sclerotiorum CBMAI 849, Aspergillus sydowii Ce19, Beauveria felina CBMAI 738, Mucor racemosus CBMAI 847, Penicillium citrinum CBMAI 1186, Penicillium miczynskii Ce16, P. miczynskii Gc5, Penicillium oxalicum CBMAI 1185, and Trichoderma sp. Gc1) catalyzed the asymmetric bioconversion of iodoacetophenones 1-3 to corresponding iodophenylethanols 6-8. All the marine fungi produced exclusively (S)-ortho-iodophenylethanol 6 and (S)-meta-iodophenylethanol 7 in accordance to the Prelog rule. B. felina CBMAI 738, P. miczynskii Gc5, P. oxalicum CBMAI 1185, and Trichoderma sp. Gc1 produced (R)-para-iodophenylethanol 8 as product anti-Prelog. The bioconversion of para-iodoacetophenone 3 with whole cells of P. oxalicum CBMAI 1185 showed competitive reduction-oxidation reactions.

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A high-performance liquid chromatographic method using polar organic mode was developed to analyze albendazole (ABZ), albendazole sulfone (ABZSO(2)) and the chiral and active metabolite albendazole sulfoxide (ABZSOX, ricobendazole) that was further applied in stereoselective fungal biotransformation studies. The chromatographic separation was performed on a Chiralpak AS column using acetonitrile:ethanol (97:3, v/v) plus 0.2% triethylamine and 0.2% acetic acid as the mobile phase at a flow rate of 0.5 mL min(-1). The present study employed hollow fiber liquid-phase microextraction as sample preparation. The method showed to be linear over the concentration range of 25-5000 ng mL(-1) for each ABZSOX enantiomer, 200-10,000 ng mL(-1) for ABZ and 50-1000 ng mL(-1) for ABZSO(2) metabolite with correlation coefficient (r)> 0.9934. The mean recoveries for ABZ, rac-ABZSOX and ABZSO(2) were, respectively, 9%, 33% and 20% with relative standard deviation below 10%. Within-day and between-day precision and accuracy assays for these analytes were studied at three concentration levels and were lower than 15%. This study opens the door regarding the possibility of using fungi in obtaining of the active metabolite ricobendazole. Nigrospora sphaerica (Sacc.) E. W. Mason (5567), Pestalotiopsis foedans (VR8), Papulaspora immersa Hotson (SS13) and Mucor rouxii were able to stereoselectively metabolize ABZ into its chiral metabolite. Among them, the fungus Mucor rouxii was the most efficient in the production of (+)-ABZSOX. (C) 2011 Elsevier B.V. All rights reserved.

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Nine strains of marine-derived fungi (Aspergillus sydowii Ce15, A. sydowii Ce19, Aspergillus sclerotiorum CBMAI 849, Bionectria sp. Ce5, Beauveria felina CBMAI 738, Cladosporium cladosporioides CBMAI 857, Mucor racemosus CBMAI 847, Penicillium citrinum CBMAI 1186, and Penicillium miczynskii Gc5) were screened, catalyzing the asymmetric bioreduction of 1-(4-methoxyphenyl) ethanone 1 to its corresponding 1-(4-methoxyphenyl) ethanol 2. A. sydowii Ce15 and Bionectria sp. Ce5 produced the enantiopure (R)-alcohol 2 (>99% ee) in accordance with the anti-Prelog rule and, the fungi B. felina CBMAI 738 (>99% ee) and P. citrinum CBMAI 1186 (69% ee) in accordance with the Prelog rule. Stereoselective bioreduction by whole cells of marine-derived fungi described by us is important for the production of new reductases from marine-derived fungi.

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Ocean Drilling Program Leg 167 represents the first time since 1978 that the North American Pacific margin was drilled to study ocean history. More than 7500 m of Quaternary to middle Miocene (14 Ma) sediments were recovered from 13 sites, representing the most complete stratigraphic sequence on the California margin. Diatoms are found in most samples in variable abundance and in a moderately well-preserved state throughout the sequence, and they are often dominated by robust, dissolution-resistant species. The Neogene North Pacific diatom zonation of Yanagisawa and Akiba (1998, doi:10.5575/geosoc.104.395) best divides the Miocene to Quaternary sequences, and updated ages of diatom biohorizons estimated based on the geomagnetic polarity time scale of Cande and Kent (1995, doi:10.1029/94JB03098) are slightly revised to adjust the differences between the other zonations. Most of the early middle Miocene through Pleistocene diatom datum levels that have been proven to be of stratigraphic utility in the North Pacific appear to be nearly isochronous within the level of resolution constrained by sample spacing. The assemblages are characterized by species typical of middle-to-high latitudes and regions of high surface-water productivity, predominantly by Coscinodiscus marginatus, Stephanopyxis species, Proboscia barboi, and Thalassiothrix longissima. Latest Miocene through Pliocene assemblages in the region of the California Current, however, are intermediate between those of subarctic and subtropical areas. As a result, neither the existing tropical nor the subarctic (high latitude) zonal schemes were applicable for this region. An interval of pronounced diatom dissolution detected throughout the Pliocene sequence apparently correspond to a relatively warmer paleoceanographic condition resulting in a slackening of the southward flow of the California Current.

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Ecosystems at high northern latitudes are subject to strong climate change. Soil processes, such as carbon and nutrient cycles, which determine the functioning of these ecosystems, are controlled by soil fauna. Thus assessing the responses of soil fauna communities to environmental change will improve the predictability of the climate change impacts on ecosystem functioning. For this purpose, trait assessment is a promising method compared to the traditional taxonomic approach, but it has not been applied earlier. In this study the response of a sub-arctic soil Collembola community to long-term (16 years) climate manipulation by open top chambers was assessed. The drought-susceptible Collembola community responded strongly to the climate manipulation, which substantially reduced soil moisture and slightly increased soil temperature. The total density of Collembola decreased by 51% and the average number of species was reduced from 14 to 12. Although community assessment showed species-specific responses, taxonomically based community indices, species diversity and evenness, were not affected. However, morphological and ecological trait assessments were more sensitive in revealing community responses. Drought-tolerant, larger-sized, epiedaphic species survived better under the climate manipulation than their counterparts, the meso-hydrophilic, smaller-sized and euedaphic species. Moreover it also explained the significant responses shown by four taxa. This study shows that trait analysis can both reveal responses in a soil fauna community to climate change and improve the understanding of the mechanisms behind them.

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Extreme weather events can have negative impacts on species survival and community structure when surpassing lethal thresholds. Extreme winter warming events in the Arctic rapidly melt snow and expose ecosystems to unseasonably warm air (2-10 °C for 2-14 days), but returning to cold winter climate exposes the ecosystem to lower temperatures by the loss of insulating snow. Soil animals, which play an integral part in soil processes, may be very susceptible to such events depending on the intensity of soil warming and low temperatures following these events. We simulated week-long extreme winter warming events - using infrared heating lamps, alone or with soil warming cables - for two consecutive years in a sub-Arctic dwarf shrub heathland. Minimum temperatures were lower and freeze-thaw cycles were 2-11 times more frequent in treatment plots compared with control plots. Following the second event, Acari populations decreased by 39%; primarily driven by declines of Prostigmata (69%) and the Mesostigmatic nymphs (74%). A community-weighted vertical stratification shift occurred from smaller soil dwelling (eu-edaphic) Collembola species dominance to larger litter dwelling (hemi-edaphic) species dominance in the canopy-with-soil warming plots compared with controls. The most susceptible groups to these winter warming events were the smallest individuals (Prostigmata and eu-edaphic Collembola). This was not apparent from abundance data at the Collembola taxon level, indicating that life forms and species traits play a major role in community assembly following extreme events. The observed shift in soil community can cascade down to the micro-flora affecting plant productivity and mineralization rates. Short-term extreme weather events have the potential to shift community composition through trait composition with potentially large consequences for ecosystem development.

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The stratigraphic ranges and relative abundances of selected diatoms and silicoflagellates are presented from three Neogene sedimentary sequences from the subantarctic South Atlantic. These data were compiled from Hole 699A in the southwest South Atlantic and Holes 704A and 704B in the southeast South Atlantic. Thirty-five samples were examined from a 67.5-m section of Hole 699A, which is mostly late Miocene or younger in age. A total of 225 samples was examined from the upper 569.1-m lower Miocene to Quaternary section in Holes 704A and 704B. Although the partial census of the Site 704 sequences is only preliminary, it reveals that the Neogene is remarkably complete and serves as a reference for further detailed examination of an important biostratigraphic-magnetostratigraphic reference section for the Neogene record of the Southern Ocean.

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A diatom biostratigraphy is presented for middle Miocene through Quaternary sediments recovered from the Chatham Rise east of New Zealand's South Island. The upper 590 m of the 639.5-m composite-section Site 594 represents approximately 16 m.y. and is characterized by moderately to very poorly preserved diatoms of antarctic to temperate affinity. Pliocene through Quaternary assemblages are poorly preserved and dominated by antarctic-subantarctic species which provide detailed biostratigraphic control. Recognized are 11 of 14 zones of the middle upper Miocene to Quaternary Neogene Southern Ocean diatom zonation (NSD 7-NSD 20) of Ciesielski (1983; this chapter). Four Neogene Southern Ocean diatom zones (NSD 3-NSD 6) are recognized in the lower middle Miocene to middle upper Miocene of Site 594. Assemblages of this interval have a mixed high-latitude and temperate affinity; however, poor preservation limits correlation to high- and temperate-latitude zonal schemes. Neogene North Pacific diatom zones and subzones of NNPD 3 through NNPD 5 (Barron, in press, b) are correlated to Neogene Southern Ocean diatom zones NSD 3 through NSD 7: the upper portions of the Actinocyclus ingens Zone (NNPD 3) is correlative to the upper Nitzschia maleinterpretaria Zone (NSD 3); the Denticulopsis lauta Zone (NNPD 4) and Subzones a and b are correlative to the lower Coscinodiscus lewisianus Zone (NSD 4); and the D. hustedtü-D. lauta Zone (NNPD 5) and its Subzones a through d encompass the upper C. lewisianus Zone (NSD 4), N. grossepunctata Zone (NSD 5), N. denticuloides Zone (NSD 6), and the lower D. hustedtii-D. lauta Zone (NSD 7). A major disconformity spans the late Gilbert to early Gauss Chron (3.9-2.8 Ma). A second disconformity brackets the Miocene/Pliocene boundary; the section missing covers late Chron 5 and the early Gilbert chron (5.5-4.6 Ma). The remainder of the siliceous-fossil-bearing Miocene sediments at Site 594 appear to be correlative to lower paleomagnetic Chronozone 5 through upper Chronozone 16. Uppermost lower Miocene or lowermost middle Miocene sediments in the basal 50 m of Hole 594A are barren of diatoms.