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941.
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Matthew B. Greenblatt Jung-Min Kim Hwanhee Oh Kwang Hwan Park Min-Kyung Choo Yasuyo Sano Coralee E. Tye Ziedonis Skobe Roger J. Davis Jin Mo Park Marianna Bei Laurie H. Glimcher Jae-Hyuck Shim 《The Journal of biological chemistry》2015,290(1):284-295
An improved understanding of the molecular pathways that drive tooth morphogenesis and enamel secretion is needed to generate teeth from organ cultures for therapeutic implantation or to determine the pathogenesis of primary disorders of dentition (Abdollah, S., Macias-Silva, M., Tsukazaki, T., Hayashi, H., Attisano, L., and Wrana, J. L. (1997) J. Biol. Chem. 272, 27678–27685). Here we present a novel ectodermal dysplasia phenotype associated with conditional deletion of p38α MAPK in ectodermal appendages using K14-cre mice (p38αK14 mice). These mice display impaired patterning of dental cusps and a profound defect in the production and biomechanical strength of dental enamel because of defects in ameloblast differentiation and activity. In the absence of p38α, expression of amelogenin and β4-integrin in ameloblasts and p21 in the enamel knot was significantly reduced. Mice lacking the MAP2K MKK6, but not mice lacking MAP2K MKK3, also show the enamel defects, implying that MKK6 functions as an upstream kinase of p38α in ectodermal appendages. Lastly, stimulation with BMP2/7 in both explant culture and an ameloblast cell line confirm that p38α functions downstream of BMPs in this context. Thus, BMP-induced activation of the p38α MAPK pathway is critical for the morphogenesis of tooth cusps and the secretion of dental enamel. 相似文献
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945.
Jing Lu Huanying Zheng Xue Guo Yong Zhang Hui Li Leng Liu Hanri Zeng Ling Fang Yanling Mo Hiromu Yoshida Lina Yi Tao Liu Shannon Rutherford Wenbo Xu Changwen Ke 《Applied and environmental microbiology》2015,81(7):2311-2319
An aseptic meningitis outbreak occurred in Luoding City of Guangdong, China, in 2012, and echovirus type 30 (ECHO30) was identified as the major causative pathogen. Environmental surveillance indicated that ECHO30 was detected in the sewage of a neighboring city, Guangzhou, from 2010 to 2012 and also in Luoding City sewage samples (6/43, 14%) collected after the outbreak. In order to track the potential origin of the outbreak viral strains, we sequenced the VP1 genes of 29 viral strains from clinical patients and environmental samples. Sequence alignments and phylogenetic analyses based on VP1 gene sequences revealed that virus strains isolated from the sewage of Guangzhou and Luoding cities matched well the clinical strains from the outbreak, with high nucleotide sequence similarity (98.5% to 100%) and similar cluster distribution. Five ECHO30 clinical strains were clustered with the Guangdong environmental strains but diverged from strains from other regions, suggesting that this subcluster of viruses most likely originated from the circulating virus in Guangdong rather than having been more recently imported from other regions. These findings underscore the importance of long-term, continuous environmental surveillance and genetic analysis to monitor circulating enteroviruses. 相似文献
946.
Spiradiclis glandulosa L. Wu & Q. R. Liu, a new species from limestone areas in southern China, is described and illustrated here. This new species is similar to S. umbelliformis, but can be distinguished from the latter mainly by its abaxial leaf blade with densely set yellow glandule‐like spots (vs abaxially pilosulous), calyx lobes oblong‐laceolate, ca 4–6 mm long (vs ovate‐triangular, ca 0.6 mm), corolla tube inside densely pubescent above the middle and onto lobes in both forms (vs inside with villous ring above base), and capsules villosulous (vs glabrescent). 相似文献
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949.
Spatiotemporal variations affect uptake of inorganic and organic nitrogen by dominant plant species in an alpine wetland 总被引:1,自引:0,他引:1
Aims
Dominant plant species may coexist and maintain high productivity in alpine wetland through available nitrogen (N) niche differentiation over time and space. We tested the hypotheses that dominant plant species differ in uptake of inorganic and organic N and that such differences depend on soil depth and season.Methods
We conducted a short-term 15N-labeling experiment in an alpine wetland on the Tibetan Plateau. The experiment used a factorial design with three N forms (nitrate, ammonium and glycine), three soil depths (0–5, 5–10 and 10–15 cm), two seasons (May and July) and three dominant species (Carex muliensis, C. lasiocarpa and Potentilla anserina).Results
All three species took up organic N (glycine), but showed different patterns over seasons and depths. 15N uptake rate was higher in May than in July in C. muliensis and C. lasiocarpa, but lower in May than in July in P. anserina. C. muliensis took up more 15NH4 + and 15NO3 ? than glycine-15N at all soil depths. C. lasiocarpa took up more glycine-15N than 15NH4 + or 15NO3 at 5–10 cm depth. P. anserina showed little difference in uptake at any soil depths.Conclusions
Dominant species in alpine wetland are able to take up both organic and inorganic N, but show different patterns depending on N form, soil depth, season and their interactions. 相似文献950.