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The ADAM (A Disintegrin and Metalloprotease) family of transmembrane proteins plays important roles in embryogenesis and tissue formation based on their multiple functional domains. In the present study, for the first time, the expression patterns of the premature and the active forms of six members of the ADAM proteins — ADAM9, ADAM10, ADAM12, ADAM17, ADAM22 and ADAM23 — in distinct parts of the developing chicken brain were investigated by quantitative Western blot analysis from embryonic incubation day (E) 10 to E20. The results show that the premature and the active forms of various ADAM proteins are spatiotemporally regulated in different parts of the brain during development, suggesting that the ADAMs play a very important role during embryonic development.
Given the finite resources of seed production, a trade-off between seed weight and number was expected. However, it still remains unclear how the seed weight-number trade-off changes if there are some mechanisms to enhance resource acquirements during the fruit developments. Sinopodophyllum hexandrum presents furled leaves in flowering time but unfurled leaves in fruiting time, which is considered to enhance the photosynthates to fruit development. To determine the relationship between seed weight and number of S. hexandrum, we examined the altitudinal variations and the relationship between seed weight and number in the fruits from 27 populations of in 2009 and 2010. Our results showed that, along the altitudinal gradient, seed weight decreased significantly but seed number increased insignificantly, indicating that the selective pressure on seed production might come from seed dispersal in high altitude populations. There was no significant relationship between seed weight and number in most populations, but an inverse relationship was found between seed weight and number when the data from all populations were pooled, indicating the seed weight-number trade-off and resource limitation of seed production in S. hexandrum on species level. We suggested that the two unfurled leaves of S. hexandrum might contribute to the resources allocated to the fruit development via enhancing photosynthates, which might mask the seed weight-number trade-off on population level to some degree.
The investigation of mechanism of species coexistence promotes understanding of the mechanistic processes behind community ecology and ecosystem functions. Niche theory declares that species coexistence within a community must partition the resources of their environment. Two sympatric and morphologically similar bat species, Rhinolophus affinis and Rhinolophus pearsoni, provided a unique opportunity to test the causal mechanism of coexistence. Previous study showed that their coexistence was promoted not by the trophic and spatial niche differentiation but the relatively high abundance of prey resources, which was not in accord with the prediction of niche theory. Here, therefore, we reanalyzed the dietary composition by fecal analysis and surveyed the feeding time of both species. Our results showed that R. affinis and R. pearsoni hunt mainly mostly on Coleoptera and Lepidoptera, and there was a very high overlap (0.84) of trophic niche between the two species. However, significant difference in the duration of the activity period between both species was detected, which illustrated that temporal partitioning of prey resource use facilitated their coexistence. Additionally, our work highlighted the importance of integration of the traditional methods and next-generation sequencing methods for identifying dietary composition of carnivores, and suggested that ongoing studies of species coexistence must consider simultaneously multiple niche axes.
The Tc1 transposable element has been found in a wide variety of organisms including vertebrates, insects and fungi but has not been previously reported in Microsporidia. In this study we characterize an intact DNA transposon (NbTc1) from the microsporidian Nosema bombycis. This transposable element encodes a 337 amino acid transposase sequence, which contains the D,D34E functional motif required for transposition. A Southern blot of N. bombycis DNA separated by pulsedesis shows that copies of the NbTc1 transposon are present on 10 of the 14 chromosomes of N. bombycis. Amino acid sequence variation among copies of the NbTc1 is low, suggesting a conserved function for this transposon within N. bombycis. Phylogenetic analysis indicates that NbTc1 is a new member of the Tc1 family lineage, quite distinct from all previously described Tc1 elements, including those from fungi, indicating that NbTc1 forms a unique clade of the Tc1 superfamily. However, the Tc1 transposon is too divergent to resolve the major phylogenetic relationships among these superfamilies. Reverse transcriptase PCR and Solexa sequencing suggest that NbTc1 possesses transcriptional activity. Considering the interest in Microsporidia as biological control agents, the NbTc1 transposon may be a useful vector for the efficient transfection of these important parasites into host species.
Soil microorganisms play important roles in the dynamic regulation of organic matter in the forest ecosystem and are affected by different revegetation types. To reveal the influence of different revegetation types on soil microorganisms, we examined soil properties, soil microbial activity and diversity in Baishilazi Nature Reserve, including two planted coniferous forests (LG: Larix gmelinii, PK: Pinus koraiensis), two natural secondary broadleaf forests (JM: Juglans mandshurica, QM: Quercus mongolica), and one conifer-broadleaf forest (CB). Biolog-Eco plates were used to study soil microbial functional diversity. We found that the content of soil total C and total N existed higher under the broadleaf forests (JM, QM) than conifer-broadleaf forest (CB) and coniferous forests (LG, PK). Carbon source utilization capacity and soil microbial activity showed significant variations among different revegetation types. Soil microbial activity of natural secondary forests was significantly higher than planted coniferous forests, and JM created the highest soil microbial activity. Heatmap and PCA plot clearly differentiated among the different samples. The broadleaf forests, conifer-broadleaf forest and coniferous forests were well separated from each other, especially along the PC1, and the position of conifer-broadleaf forest was intermediate. The findings of canonical correspondence analysis (CCA) suggested that soil total C and total N were the main factors affecting soil microbial functional diversity. This study investigated how shifts in soil microbial functional diversity affected by different revegetation types were operational indicators of soil quality in Baishilazi Nature Reserve and that the JM created the highest carbon source utilization soil microbial diversity.
In this study, two pairs of oligonucleotide primers were designed according to the nucleotide sequence of the internal transcribed spacers (ITSs) of Babesia bigemina and B. bovis isolates from China. The primers were used in a multiplex PCR to detect parasite DNA in blood samples from cattle. There was no cross reactions with B. ovata, B. major, B. sp. Kashi, Theileria annulata, T. sergenti, T. sinensis or normal bovine DNA. The sensitivity of multiplex PCR assay was 1 pg and 10 pg DNA for B. bigemina and B. bovis, respectively. A total of 260 field blood samples collected from cattle in five provinces of China were analyzed by multiplex PCR and light microscopy. PCR testing revealed that 7.3% (19/260) and 5.8% (15/260) of cattle were positive for B. bigemina and B. bovis and 1.2% (3/260) of cattle were co-infected with B. bigemina and B. bovis. Using light microscopy, 2.3% (6/260) and 1.5% (4/260) of cattle were infected by B. bigemina and B. bovis, respectively, and no co-infection was found. The results showed that the multiplex PCR developed in the present study could be an alternative diagnostic tool for the detection of B. bovis and B. bigemina infection in cattle.
The health condition of rolling bearing can directly influence to the efficiency and lifecycle of rotating machinery, thus monitoring and diagnosing the faults of rolling bearing is of great importance. Unfortunately, vibration signals of rolling bearing are usually overwhelmed by external noise, so the fault frequencies of rolling bearing cannot be readily obtained. In this paper, an improved feature extraction method called IMFs_PE, which combines the multivariate empirical mode decomposition with the permutation entropy, is proposed to extract fault frequencies from the noisy bearing vibration signals. First, the raw bearing vibration signals are filtered by an optimal band-pass filter determined by SK to remove the irrelative noise which is not in the same frequency band of fault frequencies. Then the filtered signals are processed by the IMFs_PE to get rid of the relative noise which is in the same frequency band of fault frequencies. Finally, a frequency domain condition indicator FFR(Fault Frequency Ratio), which measures the magnitude of fault frequencies in frequency domain, is calculated to compare the effectiveness of the feature extraction methods. The feature extraction method proposed in this paper has advantages of removing both irrelative noise and relative noise over other feature extraction methods. The effectiveness of the proposed method is validated by simulated and experimental bearing signals. And the results are shown that the proposed method outperforms other state of the art algorithms with regards to fault feature extraction of rolling bearing
The link between the acute toxicity of heavy metals on algae and the bioadsorption capacity of heavy metals by algae has seldom been reported. In the present study, an acute toxicity experiment was carried out to assess the toxic effects of Pb, Cu, and Cd for Chlorella sorokiniana, and the 96 h IC₅₀ values were 0.249 mg/L, 0.485 mg/L, 46.108 mg/L, and 21.00 mg/L for Cu, Cd, Pb (total), and Pb (free ion), respectively, which implied that Chlorella sorokiniana showed high tolerance to Pb compared to Cu and Cd. Pb distribution analysis indicated that 73.40% to 98.15% of free Pb ions were accumulated on the algae cell wall to avoid further intracellular accumulation, resulting in irreversible metabolic disorders. Then the adsorption capacity of Chlorella was explored. It could be found that the Langmuir model (the R² were 0.988 and 0.962 for living and lifelss cells, respectively) was fit to explain the adsorption equilibrium data and the qₑ calculated by this model were 1.54 and 2.97 mg /10¹⁰ cells for living and lifeless cells, respectively, which was consistent with the experimental result. In the competitive adsorption, Chlorella exhibited a greater affinity for Pb with the higher removal rate compared to Cu and Ni. Therefore, the renewable Chlorella sorokiniana and its dramatic resistance to Pb may serve as a potential biosorbent for Pb in the future.
We investigated the effects of nutrient levels on the abundance and diversity of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB), seven surface sediment samples from small reservoirs at different nutrient levels were collected from the eastern, central, and western parts of Huashan watershed in Chuzhou, Anhui Province to determine the abundance and community composition of AOA and AOB. The results showed that the abundance of bacterial amoA gene (1.85×107 to 2.86×108 g/dry sediment) was higher than that of archaeal amoA gene (1.25×105 to 1.23×106 g/dry sediment) in all sediment samples. The abundance of the archaeal amoA gene exhibited significant positive correlations with total nitrogen concentrations, whereas the abundance of bacterial amoA gene showed significantly negative correlation with pH. Archaeal amoA gene sequences included Nitrososphaera and Nitrosopumilus clusters and the majority of Nitrosospira and Nitrosomonas oligotropha lineages.
ReNcell VM is an immortalized human neural progenitor cell line with the ability to differentiate in vitro into astrocytes and neurons, in which the Wnt/β-catenin pathway is known to be involved. However, little is known about kinetic changes of this pathway in human neural progenitor cell differentiation. In the present study, we provide a quantitative profile of Wnt/β-catenin pathway dynamics showing its spatio-temporal regulation during ReNcell VM cell differentiation. We show first that T-cell factor dependent transcription can be activated by stabilized β-catenin. Furthermore, endogenous Wnt ligands, pathway receptors and signaling molecules are temporally controlled, demonstrating changes related to differentiation stages. During the first three hours of differentiation the signaling molecules LRP6, Dvl2 and β-catenin are spatio-temporally regulated between distinct cellular compartments. From 24 h onward, components of the Wnt/β-catenin pathway are strongly activated and regulated as shown by mRNA up-regulation of Wnt ligands (Wnt5a and Wnt7a), receptors including Frizzled-2, -3, -6, -7, and -9, and co-receptors, and target genes including Axin2. This detailed temporal profile of the Wnt/β-catenin pathway is a first step to understand, control and to orientate, in vitro, human neural progenitor cell differentiation.
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