排序方式: 共有18条查询结果,搜索用时 31 毫秒
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Polyana C Tizioto Jeremy F Taylor Jared E Decker Caio F Gromboni Mauricio A Mudadu Robert D Schnabel Luiz L Coutinho Gerson B Mour?o Priscila SN Oliveira Marcela M Souza James M Reecy Renata T Nassu Flavia A Bressani Patricia Tholon Tad S Sonstegard Mauricio M Alencar Rymer R Tullio Ana RA Nogueira Luciana CA Regitano 《遗传、选种与进化》2015,47(1)
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The aim of this study was to determine the first effect of lead on microbial activity in soil. The study was carried out in the soil samples from four different radish (Raphanus sativus L. var. radicula, Brassicaceae) fields along the highway in a district (Kadirli, Osmaniye) of the Eastern Mediterranean Region, Turkey. After the calculation of Pb contents, the Pb amounts of the soil samples were brought up to 50 and 100 mg Pb kg?1 by treatment with Pb(NO 3 ) 2 , and the samples for the carbon and the nitrogen mineralization were incubated under controlled conditions (28°C, constant moist). The carbon mineralization was determined by a CO 2 respiration method for 30 days. The nitrogen mineralization was observed in vitro for 6 weeks. The untreated group was statistically different from the 50 and 100 mg Pb kg?1 treatments in the aspect of the C(CO 2 ) outlet during mineralization (P ≤ 0.05), but difference between the 50 and 100 mg Pb kg?1 treatments was not significant. NH 4 -N and NO 3 -N contents of each soil were shown differences between across treatments. Based on these results, it is possible to conclude that the addition of 50 and 100 mg Pb kg?1 provided a toxic effect threshold for the microbial activity into 30 days. 相似文献
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Twelve fungi namelyAlternaria alternata, Aspergillus flavus, A niger, A ochraceus, Actinomucor repens, Capnodoium spp., Curvularia lunata, Fusarium
pallidoroseum, F solani, F verticillioides, Penicillium citrinum and Rhizopus stolonifer were recorded from samples ofAegle marmelos, Aesculus indica, Buchanania lanzan andPinus gerardiana. In case ofPrunus amygdalus only Rstolonifer was recorded. A significant variation in pattern of mycoflora incidence was observed in terms of source and season. Fungal
infestation in most of the substrates was found to be highest during monsoon. Aflatoxins were the most common mycotoxins elaborated
by different isolates ofA flavus obtained fromA marmelos, B lanzan andP gerardiana. The amount of aflatoxins produced by the toxigenic isolates ofA flavus was in the range of traces to 0.9–26.0 μg/ml inA marmelos, 0.8–17.5 μg/ml inP gerardiana and 0.65–13.2 μg/ml inB lanzan. The percentage toxigenicity was comparatively lower in the isolates of other mycotoxigenic fungi. Aflatoxins were detected
almost in all the samples analyzed for mycotoxin contamination. However, traces of zearalenone were detected inA marmelos. The concentration of aflatoxin B1 was in the range of 0.13–0.75 μg/g inA marmelos, 0.09–0.60 μg/g inP gerardiana and 0.01–0.20 ug/g inB lanzan. Mycotoxins were not detected inAesculus indica andPrunus amygdalus. 相似文献
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Kozhedub RG Cheremushkin EA Sviderskaia NE Kozhechkina SN Koshtoiants OKh Korol'kova TA Knipst IN Seredenin SB 《Zhurnal vysshe? nervno? deiatelnosti imeni I P Pavlova》2005,55(4):518-526
With the aim to reveal features of the neocortical spatiotemporal organization of potentials characteristic of different genetically predetermined emotional levels, momentary values of EEG potentials were analyzed in inbred rats of MR and MNRA strains. A topogram was described by a basic parameter such as its general level (the mean of momentary values of potentials derived from 24 symmetrical electrodes bilaterally implanted into the brain cortex) and a similarity coefficient (correlation between the set of its momentary values and that of a standard topogram). The general level and similarity coefficient values were calculated for a series of successive topograms individually for the right and left hemisphere. Also, right- and left-side power spectra of these series were calculated. In rats of MR strain, significant (p < 0.05) peaks in the general level and similarity coefficient spectra were observed in the delta (2.0 Hz), teta (6.5 Hz) and alpha (9 Hz) frequency bands. In this strain, the general level power was higher at the right side, and the similarity coefficient power displayed the left-side dominance. In rats of MNRA strain, peaks in the delta(2.0 Hz) band coinsided in the general level and similarity coefficient spectra, whereas, independently, the general level spectra had peaks in the theta band (7.0 Hz), and similarity coefficient had peaks at frequencies 3.0, 4.5, and 6.0 Hz. The left-side general level spectral power was higher than the right-side general level spectral power in the delta and lower in the high-frequency theta bands. The similarity coefficient power displayed the left-side dominance for the peaks in the delta (2.0 Hz) and theta (3.0 Hz) bands, and it displayed the right-side dominance for the peaks in the theta (4.5 Hz) band. The specific features of the cortical spatiotemporal organization of potentials revealed in rats of MR and MNRA strains suggest different modes of functioning of at least two systems, reticulo-thalamo-corticaland hippocampo-cortical. 相似文献
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Distribution and conservation of mobile elements in the genus Drosophila 总被引:13,自引:1,他引:12
Essentially nothing is known of the origin, mode of transmission, and
evolution of mobile elements within the genus Drosophila. To better
understand the evolutionary history of these mobile elements, we examined
the distribution and conservation of homologues to the P, I, gypsy, copia,
and F elements in 34 Drosophila species from three subgenera. Probes
specific for each element were prepared from D. melanogaster and hybridized
to genomic DNA. Filters were washed under conditions of increasing
stringency to estimate the similarity between D. melanogaster sequences and
their homologues in other species. The I element homologues show the most
limited distribution of all elements tested, being restricted to the
melanogaster species group. The P elements are found in many members of the
subgenus Sophophora but, with the notable exception of D. nasuta, are not
found in the other two subgenera. Copia-, gypsy-, and F-element homologues
are widespread in the genus, but their similarity to the D. melanogaster
probe differs markedly between species. The distribution of copia and P
elements and the conservation of the gypsy and P elements is inconsistent
with a model that postulates a single ancient origin for each type of
element followed by mating-dependent transmission. The data can be
explained by horizontal transmission of mobile elements between
reproductively isolated species.
相似文献
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ETIENNE KORNOBIS SNÆBJÖRN PÁLSSON BJARNI K. KRISTJÁNSSON JÖRUNDUR SVAVARSSON 《Molecular ecology》2010,19(12):2516-2530
Two endemic groundwater arthropod crustacean species, Crangonyx islandicus and Crymostygius thingvallensis, were recently discovered on the mid‐Atlantic volcanic island of Iceland. The extent of morphological differences from closest relatives, endemism, along with the geographic isolation of Iceland and its complete coverage by glaciers 21 000 years ago, suggests that these two species have survived glaciation periods in sub‐glacial refugia. Here we provide strong support for this hypothesis by an analysis of mitochondrial genetic variation within Crangonyx islandicus. Our results show that the species is divided into several distinct monophyletic groups that are found along the volcanic zone in Iceland, which have been separated by 0.5 to around 5 million years. The genetic divergence between groups reflects geographic distances between sampling sites, indicating that divergence occurred after the colonization of Iceland. The genetic patterns, as well as the dependency of genetic variation on distances from the tectonic plate boundary and altitude, points to recent expansion from several refugia within Iceland. This presents the first genetic evidence of multicellular organisms as complex as crustacean amphipods which have survived glaciations beneath an ice sheet. This survival may be explained by geothermal heat linked to volcanic activities, which may have maintained favourable habitats in fissures along the tectonic plate boundary in Iceland during glaciations. 相似文献