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991.
Stimulated neutrophils from patients with autosomal recessive chronic granulomatous disease fail to phosphorylate a Mr-44,000 protein 总被引:5,自引:0,他引:5
Phagocytosing neutrophils, monocytes, macrophages and eosinophils produce a burst of non-mitochondrial respiration that is important for the killing and digestion of microbes. Much of the information about the oxidase system involved comes from studies on patients with chronic granulomatous disease (CGD), a syndrome in which an undue predisposition to infection results from complete absence of this burst of stimulated respiratory activity. The basis of the oxidase activity is an electron transport chain, the only established component of which is a very unusual b-type cytochrome (b-245) (ref. 2). The molecular defect in the X-linked subgroup of CGD is the absence of this cytochrome b-245, which, however, appears to be normal in those subjects with the autosomal recessive mode of inheritance. In an attempt to identify an abnormality of activation, or an absence or malfunction of a proximal component of the electron transport chain in this latter group, we examined protein phosphorylation in neutrophils after activation of the oxidase with phorbol myristate acetate. All four of the patients studied demonstrated a selective lack of the enhanced phosphorylation of a protein of relative molecular mass (Mr) 44,000 (44K) that was observed in normal subjects and in two CGD patients with an X-linked inheritance. This molecule, therefore, could be an important functional component of the oxidase. 相似文献
992.
H. Engeln J. Krause E. Wachmann W. Köhler 《Cellular and molecular life sciences : CMLS》1985,41(5):611-612
Summary The ultrastructure of the compound eyes of several photonegative selection lines and their unselected photopositive controls of five species of themelanogaster subgroup was analyzed. A qualitative phenotypic change concerning the rhabdomeres in one of the photonegative selection lines ofD. mauritiana could be detected. It was proved that this structural aberration of the rhabdomeres is caused by a parallel mutation of the mutantora (outer rhabdomeres absent) ofD. melanogaster. 相似文献
993.
The T/t-complex of the mouse includes a series of recessive lethal and semi-lethal mutations but, despite such lethalities, mutant t-haplotypes are found in high frequency in wild mouse populations. This polymorphism is apparently maintained because heterozygous males preferentially transmit the t-bearing chromosome to their offspring. Despite many attempts to define the basis of the transmission ratio distortion, it has been unclear whether this is because t-bearing sperm have better than average fertilizing ability or whether +-bearing sperm in heterozygous males are rendered defective. To examine this point, we constructed male (XY in equilibrium XY) chimaeras containing +/+ and +/tw73 genotypes, marked respectively by albino and pigmented coat colours, and two isozyme variants. Such males produce a mixture of three different sperm types: +-bearing sperm from the +/+ genotype, +-bearing sperm from the +/t genotype, and t-bearing sperm from the +/t genotype. Appropriate matings can distinguish between these three types, and our data, reported here, show that t-bearing sperm in chimaeric mice maintain their advantage over their 'meiotic partners' but do not have any advantage over sperm from the +/+ genotype. 相似文献
994.
Synthesis of brome mosaic virus subgenomic RNA in vitro by internal initiation on (-)-sense genomic RNA 总被引:37,自引:0,他引:37
The genomes of many (+)-stranded RNA viruses, including plant viruses and alphaviruses, consist of polycistronic RNAs whose internal genes are expressed via subgenomic messenger RNAs. The mechanism(s) by which these subgenomic mRNAs arise are poorly understood. Based on indirect evidence, three models have been proposed: (1) internal initiation by the replicase on the (-)-strand of genomic RNA, (2) premature termination during (-)-strand synthesis, followed by independent replication of the subgenomic RNA and (3) processing by nuclease cleavage of genome-length RNA. Using an RNA-dependent RNA polymerase (replicase) preparation from barley leaves infected with brome mosaic virus (BMV) to synthesize the viral subgenomic RNA in vitro, we now provide evidence that subgenomic RNA arises by internal initiation on the (-)-strand of genomic RNA. We believe that this also represents the first in vitro demonstration of a replicase from a eukaryotic (+)-stranded RNA virus capable of initiating synthesis of (+)-sense RNA. 相似文献
995.
Following oral or intravenous administration, a representative cognition activator drug, pramiracetam sulfate, is shown to have a pharmacologic therapeutic window at three different levels of study: learned behavior, gross EEG activity of the frontal cortex and hippocampus, and firing rate of single hippocampal neurons. 相似文献
996.
M. Aglietta A. Stacchini F. Sanavio W. Piacibello 《Cellular and molecular life sciences : CMLS》1985,41(3):375-376
Summary The effect of 2 H2 receptor antagonists (ranitidine and cimetidine) on the in vitro growth of human granulomonopoietic precursors (CFU-GM) was studied. Ranitidine, although having an anti H2 receptor activity much greater than that of cimetidine, displays the same toxicity for CFU-GM.Acknowledgments. This work was supported by CNR, Rome, PFCCN and AIRC, Milan. 相似文献
997.
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1000.
Although it is generally agreed that the giant panda (Ailuropoda melanoleuca) is a member of the order Carnivora, there has long been disagreement over whether it should be classified with bears, raccoons or as a single member of its own family. Four independent molecular and genetic measures lead to a consensus phylogeny for the giant and lesser pandas. The lesser panda diverged from New World procyonids at approximately the same time as their departure from ursids, while ancestors of the giant panda split from the ursid lineage much later, just before the radiation which led to modern bears. The giant panda's divergence was accompanied by a chromosomal reorganization which can be partially reconstructed from the ursid karyotype, but not from that of procyonids or the lesser panda. The apparently dramatic, but actually limited, distinctions between the giant panda and the bears in chromosomal and anatomical morphology provide a graphic mammalian example of the discordance of molecular and morphological (and chromosomal) evolutionary change. 相似文献