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1.
A simple, fast, precise and biologically relevant toxicity assay for screening cytotoxicity of minerals would have distinct advantages due to its cost benefits and relative savings in time. Furthermore, a bioassay to differentiate acute and chronic in vivo pulmonary reactions could have potential value as predictors of fibrogenicity and pathogenicity. In this study we examined the potential use of lucigenin as a probe to evaluate the correlation between chemiluminescence (CL) generated by alveolar macrophages with the known cytotoxicity and patho genicity by conventional bioassays. In this study, we used small doses of dust (20 microg) to minimize cellular overload and to maintain homeostasis. Crystalline silica a highly fibrogenic dust was used as positive control and results are compared with those for bentonite, kaolin and talc. Among the three minerals compared with silica, bentonite was more reactive (27%) in CL assay and declined sharply compared to other minerals. This sudden decline in bentonite CL is caused by cytotoxicity leading to cell death. CL-induced by talc was comparable to silica and declines slowly. Kaolin on the other hand produced relatively a weaker (25%) CL compared to silica. Our data using relatively low doses of dust suggest that the CL assay may have a better predictive value in cytotoxicity evaluations compared to conventional toxicity assays. 相似文献
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Synergistic effect of morphactin on cytokinin-induced production of isoflavonoids in cell cultures of Pueraria tuberosa (Roxb. ex. Willd.) DC 总被引:1,自引:0,他引:1
Isoflavonoids, the functional molecules of Fabaceae, are under clinical trials against cancer, osteoporosis and cardiovascular
diseases. In this study, the efficacy of different plant growth regulators was evaluated for optimizing the production of
isoflavonoids in Pueraria tuberosa. The cultures were maintained in Murashige and Skoog’s medium containing 0.1 mg l−1 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) and 0.1 mg l−1 kinetin. The addition of 5.0 mg l−1 N6-(2-Isopentenyl) adenine (2iP) resulted in about ∼32-folds increase in production of isoflavonoids, while about ∼23-folds
increase was recorded in the absence of kinetin in the maintenance medium. A maximum yield of isoflavonoids (∼80 mg l−1; 82-folds increase) was obtained in cultures grown at 0.1 mg l−1 morphactin and 5.0 mg l−1 of 2iP. However, 2,4,5-T in combination with 2iP was ineffective for their production. Among different plant growth regulators
tested, maximum yields of puerarin, genistin, daidzein and genistein were 17.4, 15.9, 69.0 and 0.04 mg l−1, respectively. The study suggested that the presence of two cytokinins or 2iP with morphactin in the culture medium markedly
enhanced the production of isoflavonoids in P. tuberosa. 相似文献
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Highly selective and sensitive coumarin–triazole‐based fluorometric ‘turn‐off’ sensor for detection of Pb2+ ions 下载免费PDF全文
Exposure to even very low concentrations of Pb2+ is known to cause cardiovascular, neurological, developmental, and reproductive disorders, and affects children in particular more severely. Consequently, much effort has been dedicated to the development of colorimetric and fluorescent sensors that can selectively detect Pb2+ ions. Here, we describe the development of a triazole‐based fluorescent sensor L5 for Pb2+ ion detection. The fluorescence intensity of chemosensor L5 was selectively quenched by Pb2+ ions and a clear color change from colorless to yellow could be observed by the naked eye. Chemosensor L5 exhibited high sensitivity and selectivity towards Pb2+ ions in phosphate‐buffered solution [20 mM, 1:9 DMSO/H2O (v/v), pH 8.0] with a 1:1 binding stoichiometry, a detection limit of 1.9 nM and a 6.76 × 106 M?1 binding constant. Additionally, low‐cost and easy‐to‐prepare test strips impregnated with chemosensor L5 were also produced for efficient of Pb2+ detection and proved the practical use of this test. 相似文献
5.
We describe the activity patterns and time budget of a feral group of lion-tailed macaques that were confined to a disturbed
forest fragment of 65 ha and compare the results with those obtained for groups in protected forests. The degraded nature
of the study site was reflected in low tree densities, low specific diversity, gaps in the girth distribution of trees, and
frequent disturbance by humans. The study group of 43 subjects was twice as large as lion-tailed macaque groups in protected
habitats. They spent the most time ranging (34.0%), followed by foraging (23.7%), feeding (17.9%), resting (16.0%), and other
activities such as social interactions (8.4%). Monthly variations are significant for all activity categories except ranging.
Times spent resting and foraging are negatively correlated (r = −0.5) and show significant seasonal differences. Foraging time was highest from September to November, when key food sources such
asCullenia andArtocarpus were absent or marginally available. The study group spent most time (40.4%) at canopy levels between 21 and 30 m. They spent
more time each day ranging than resting or feeding and more time terrestrially compared with groups in protected forests.
Large group size, poor habitat quality, and seasonal variation in food availability were the major variables affecting their
time budget, and these variables accounted for differences from the time budgets of groups in protected forests. 相似文献
6.
The North-Eastern region of India is significant for biodiversity conservation because of its floristic richness and high levels of endemism. Deforestation levels are high in the region due to anthropogenic pressures. We accessed various literature sources to create a database for Meghalaya state containing information on plant species, habit, altitudinal distribution, endemism, and endangered status. Information on the existing protected area network (type, extent, and altitudinal representation) was added to the database. The database was used to assess the effectiveness of the existing protected area network in conserving the floristic biodiversity of the state. Of a total of 3331 plant species, 1236 (37.11%) are endemic of Meghalaya and 133 (4%) are confined to 'sacred forests'. However, 'sacred forests' are not legally protected areas. Only 32 220 ha (1.43% of the state's geographical area) is protected under the category of National Park or Sanctuary. Although 212 species (17.15% of the state's endemic species) occur only in Meghalaya at altitudes above 1500 m, none of the forests at these altitudes are protected as National Parks or Sanctuaries. We conclude that the existing protected area network does not effectively conserve the state's unique biodiversity and suggest measures by which its effectiveness might be increased. 相似文献
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Cell cultures of Pueraria tuberosa were grown in vessels of different sizes and 2L stirred tank bioreactor containing modified MS medium with morphactin (0.1 mg l?1) and 2iP (5.0 mg l?1) and 20% inoculum. Stable growth and total isoflavonoid yield of 76.6 mg l?1 were recorded in the cultures during scale up. This was in concordance with the persistent yield of the individual isoflavonoids regardless of the vessel size. 相似文献
8.
Shaily Menon Jorge Soberón Xingong Li A. Townsend Peterson 《Biodiversity and Conservation》2010,19(6):1599-1609
Considerable attention has focused on the climatic effects of global climate change on biodiversity, but few analyses and
no broad assessments have evaluated effects of sea-level rise on biodiversity. Taking advantage of new maps of marine intrusion
under scenarios of 1 and 6 m sea-level rise, we calculated areal losses for all terrestrial ecoregions globally, with areal
losses for particular ecoregions ranging from nil to complete. Marine intrusion is a global phenomenon, but its effects are
most prominent in Southeast Asia and nearby islands, eastern North America, northeastern South America, and western Alaska.
Making assumptions regarding faunal responses to reduced distributional areas of species endemic to ecoregions, we estimated
likely numbers of extinctions caused by sea-level rise, and found that marine-intrusion-caused extinctions of narrow endemics
are likely to be most prominent in northeastern South America, although anticipated extinctions in smaller numbers are scattered
worldwide. This assessment serves as a complement to recent estimates of losses owing to changing climatic conditions, considering
a dimension of biodiversity consequences of climate change that has not previously been taken into account. 相似文献
9.
Suspension cultures of Pueraria tuberosa, a woody legume, have been established and using different concentrations of growth regulators, sucrose, ammonium and nitrate nitrogen, attempts have been made to improve their isoflavonoid content. The cell cultures grew well on all the treatments. Up to approximately 8 folds increased isoflavonoids content was recorded in the cultures grown in MS medium modified with nitrogen and supplemented with 1 mg 1(-1) of kinetin. 相似文献
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