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Liu T.,Jiangsu University | Xue S.,The First Peoples Hospital of Lanzhou City | Wang L.,Jiangsu University
Jundishapur Journal of Microbiology | Year: 2015

Background: In Streptococcus mutans, ComCDE, a peptide-induced two-component signal transduction system, forms a closed signal transduction, and even if difunctional ComE closes this signal at its headstream to avoid its infinite amplification, it is not enough for ComE to work in a concentration-dependent manner. CslAB has a chance to regulate ComCDE by controlling extracellular competence-stimulating peptide (CSP) concentration through its processing and secretion. Objectives: To first confirm the binding properties of cslAB promoter (PcslAB) with ComE, then to uncover in vivo need of cslAB expression, and finally to unveil the role of CslAB. Materials and Methods: Electrophoretic mobility shift assay was used to confirm the binding properties of PcslAB with ComE. In vivo cslAB transcription was detected by β-galactosidase activity because its gene has been fused to cslAB operon, and finally the role of CslAB was reviewed. Results: PcslAB is a weak promoter responding to ComE and its binding appears to be negative cooperative. Although PcslAB is partially controlled by ComCDE, it can respond to ComCDE regulation. Supported by the obtained molecular evidence, CslAB acts as a stabilizer of ComCDE signal on the patterns of its expression. Conclusions: PcslAB is partially controlled by ComCDE. CslAB is a stabilizer of ComCDE signal to ensure that ComE works in a concentration-dependent manner. © 2015, Ahvaz Jundishapur University of Medical Sciences. Source

Si J.-H.,The First Peoples Hospital of Lanzhou City | Peng X.-L.,The First Peoples Hospital of Lanzhou City | Yang J.-S.,General Hospital of Lanzhou | Yan W.,The First Peoples Hospital of Lanzhou City | And 2 more authors.
Chinese Journal of Contemporary Neurology and Neurosurgery | Year: 2014

Objective: To investigate the effects of high-altitude environment on cognitive function and ultrastructure in CAI region of the hippocampus of Wistar rats in sleep deprivation (SD). Methods: SD was induced in Wistar rats by employing "flower pot" technique. Sixty-four rats were randomly divided into 2 groups: Lanzhou group (at an altitude of 1520 m) and Kekexili group (at an altitude of 4767 m), and each group was further divided into 4 subgroups according to the time of SD (0, 1, 3 and 5 d). The behaviors of rats were studied by Morris water maze test at given time points. The ultrastructure of hippocampal neurons was observed by transmission electron microscope (TEM). Results: 1) Compared with Lanzhou group, rat behavior of Kekexili group presented excitement-irritation-suppression changes with the extension of SD time, but the extent was weakened gradually, and time of sleepiness increased obviously. 2) Compared with Lanzhou group, neurons in CAI region of hippocampus showed enlarged cell body, disappeared nuclear membrane, shrunken nuclei and decreased organelle. End-feet of glia cells sticking to capillaries swelled and ruptured, and the typical synaptic structure disappeared. 3) Morris water maze test: as compared with Lanzhou group, the escape latency of Kekexili group prolonged (P<0.05, for all), the ability of distance exploration increased (P<0.05, for all), and the times across plot decreased (P<0.05, for all) in 1, 3 and 5 d of SD. Conclusions: High-altitude environment may significantly influence the cognitive function of rats in SD, and there was close correlation between the cognitive disorders and the changes in the ultrastructure of hippocampal CAI region. Source

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