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991.
992.
Muscular channelopathies such as myotonias, dyskalemic periodic paralyses (PP), malignant hyperthermia (MH), and core myopathies are caused by mutations of Na+, K+, Ca2+, and Cl? channels. Mild depolarization leads to myotonic activity. Augmented membrane depolarization can convert hyperexcitability into hypoexcitability and cause transient muscle weakness. Sustained depolarization of the plasmalemma and the t-tubular membrane is the common basis of the muscle weakness in the dominant dyskalemic PP. Serum potassium levels modulate the resting membrane potential, whereby deviations from the physiological range, e.g., by thyroid dysfunction, exacerbate membrane depolarization, and weakness. Susceptibility to MH, a potentially life-threatening hypermetabolic event, is mediated by dominant mutations which are situated in the cytoplasmic part of the Ca2+ release channel of the sarcoplasmic reticulum and increase the sensitivity to volatile anesthetics. Dominant or recessive mutations located in the sarcoplasmic part of the channel deplete the Ca2+ stores and lead to weakness and finally to a core myopathy. 相似文献
993.
S A Bitko L O Dynga A R Shikhman Z F Shmakova N I Briko 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1990,(4):3-7
The amino acid composition of cell walls and surface proteins, isolated from virulent (M+) and avirulent (M-) streptococcal strains (group A, type 29) has been determined by the method of E. H. Beachey et al. The kinetics of the lysis and proteolysis of streptococcal cell walls with muramidase and protease obtained from Actinomyces levoris and streptolysin has been studied. The constants describing the progress rates of these processes has been determined; their values in case of both lysis and proteolysis are higher in virulent strains than in avirulent ones. 相似文献
994.
995.
Construction of isogenic gonococci with variable porin structure: effects on susceptibility to human serum and antibiotics 总被引:11,自引:2,他引:9
Protein I (PI) is the most abundant protein on the gonococcal cell surface and besides its porin function it may have important properties contributing to pathogenicity. By allelic exchange using cloned PI genes from FA19 (PIA) and MS11 (PIB) and a selectable marker introduced closely downstream of these genes, we constructed sets of isogenic gonococcal strains that differ only in their PI gene. Analysis revealed that PI has a major effect on stable resistance to normal human serum, and a slight effect on low-level resistance to antibiotics. All PIA/B hybrids were hypersusceptible to serum, suggesting a possible explanation for why such hybrids do not occur in nature. 相似文献
996.
997.
998.
F Rabanal I Haro F Reig J M García-Antón 《International journal of peptide and protein research》1990,36(1):26-30
The synthesis of three hepatitis B surface antigens derived from S and pre-S proteins (adw S(140-147), [Tyr148] adw S(139-148), and adw pre-S(120-145)) has been accomplished by the continuous flow Fmoc-polyamide solid phase method. The use of different scavengers and trimethylsilyl bromide (TMSBr) in trifluoroacetic acid as deprotecting procedures is discussed. 相似文献
999.
1000.
M J Bussemakers A van Bokhoven J J van Groningen F M Debruyne J A Schalken 《Biochemical and biophysical research communications》1992,182(1):318-324
Differential hybridization analysis revealed two cDNA clones, pBUS19 and pBUS30, to be overexpressed in progressionally advanced rat prostatic tumors. Northern blot analysis suggested the clones to be related although no homology in nucleotide sequence could be shown. Isolation and characterization of a pBUS19-related clone, pJG116, and computer-assisted database comparison showed that all three clones could be mapped within a rat-specific endogenous retrovirus. The importance of overexpression of retroviral sequences in advanced prostatic cancer remains unclear. 相似文献