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71.
M. Revel 《Cellular and molecular life sciences : CMLS》1989,45(6):549-557
Summary IL-6/IFN-2 appears to be one of the important mediators of the response to viral and bacterial infections and to shock. The biological effects now associated with IL-6/IFN-2 include: stimulation of immunoglobulin secretion by mature B lymphocytes (BSF-2 activity), growth stimulation of plasmacytomas and hybridomas (HGF activity), activation of T cells, stimulation of hepatic acute phase protein synthesis (HSF activity), stimulation of hematopoiesis, cell differentiation (DIF activity), inhibition of tumor cell growth (AP activity) and other IFN-like effects. As a typical cytokine, IL-6/IFN-2 is secreted by many cell types and acts in various combinations with other interleukins and interferons. 相似文献
72.
O. E. Tsitsiloni P. P. Yialouris H. Echner W. Voelter A. A. Haritos 《Cellular and molecular life sciences : CMLS》1992,48(4):398-402
A new radioimmunoassay has been developed for thymosin 4 by generating rabbit polyclonal antibodies against the synthetic N-terminal peptide fragment 1–15 coupled to KLH. The synthetic analogue [Tyr12]-thymosin 4 (1–15) was used as tracer. This radioimmunoassay, with a useful range of 10–1000 pmoles, showed cross-reactivity with the second homologous -thymosin of man and rat (thymosin 10) but not of calf (thymosin 9). This radioimmunoassay, together with an improved radioimmunoassay for the N-terminus of parathymosin , was employed for the measurement of the levels of thymosin 4 and parathymosin in nuclear and extranuclear extracts of calf thymus. The bulk of these polypeptides was found in the extranuclear material whereas only traces were observed in the nuclear environment, which indicates the extranuclear localisation of - and -thymosins. 相似文献
73.
Summary A new N-pyridinyl benzamide was found to potentiate strongly the effects of apomorphine on the motility of reserpinized mice and on circling behavior. Since dopaminergic agonist activity could not account for this potentiation, involvement of-adrenergic agonist activity provided the only consistent explanation.Acknowledgments. We wish to thank Mr A. Decoodt for his excellent technical assistance and the Laboratoire de Chimie Therapeutique (Prof. Le Baut), Université de Nantes, for providing samples of N-PCB. 相似文献
74.
Summary The phytotoxin, tabtoxinine--lactam, is produced by severalPseudomonas syringae pathovars if adequate Zn is available, otherwise its biologically inactive form, tabtoxin, is produced. The Zn is required for the action of a peptidase which cleaves tabtoxin, releasing the toxic -lactam.This research was supported in part by U.S.D.A. Competitive Research Grant No. 83-CRCR-1-1201. 相似文献
75.
M. Schorderet 《Cellular and molecular life sciences : CMLS》1995,51(2):99-105
Alzheimer's disease is the most common type of progressive and debilitating dementia affecting aged people. In some early — as well as late-onset familial cases, a genetic linkage with chromosomes 14, 21 (early-onset) or 19 (late-onset) has been indicated. Furthermore, a direct or indirect role has been attributed to normal or structurally altered amyloid -protein (concentrated in senile plaques) and/or excessively phosphorylated tau protein (located in neurofibrillary tangles). Degeneration of cholinergic neurons and concomitant impairment of cortical and hippocampal neurotransmission lead to cognitive and memory deficits. Several compounds are being tested in attempts to prevent and/or cure Alzheimer's disease, including tacrine, which has very modest efficacy in a sub-group of patients, and new acetylcholinesterase inhibitors. Pilot experiments have also been launched using nerve growth factor (NGF) to prevent or stabilize the processes of cholinergic pathway degeneration. Alternatively, antioxidants, free radical scavengers and/or non steroidal anti-inflammatory agents may be screened as potential therapies for neurodegenerative diseases induced by multiple endogenous and/or exogenous factors. The recent use of transgenic mice, in parallel with other genetic, biochemical and neurobiological systems, in vivo and/or in vitro (cell cultures), should accelerate the discovery and development of specific drugs for the treatment of Alzheimer's disease. 相似文献
76.
Summary The mode of sclerotization ofAedes aegypti pupal and adult cuticle was examined by employing biochemical and radioactive techniques. During larval-pupal metamorphosis, tyrosine is converted to tanning precursors and is incorporated into aryl-amino adducts and -crosslinks. The major hydrolysis product of -crosslinks in pupal cases is identified to be arterenone. Examination of tanning modes in five different mosquito species shows that the ratio of quinone to -sclerotization not only differs within the life stages of the insects, but also differs between species.Study supported by N.I.H. Grant ROI-AI-14753. 相似文献
77.
J. F. Krall 《Cellular and molecular life sciences : CMLS》1987,43(6):608-610
Summary The estrogen sensitivity of cells cultured from the rat myometrium was studied by growing the cells in the absence or presence of 1 nM 17-estradiol. Following a time lag of 10 days, exposure to estrogen resulted in increased incorporation of radiothymidine by the cells. Estrogen treatment also decreased isoproterenol-dependent and GTP-dependent adenylate cyclase activity, but had no effect on basal activity. These cultured cells have been shown previously to have some properties of uterine smooth muscle. The effects estrogen has in viyro, therefore, may reflect important properties in vivo that account for the mechanism by which the sex steroid decreases the sensitivity of the myometrium to isoproterenol. 相似文献
78.
S. Kiriishi D. B. Rountree S. Sakurai L. I. Gilbert 《Cellular and molecular life sciences : CMLS》1990,46(7):716-721
Summary The prothoracic glands of a variety of insects were tested for their ability to synthesize ecdysteroids in vitro. More specifically, they were evaluated for their ability to produce 3-dehydroecdysone and ecdysone using both radioimmunoassay and reverse phase high performance liquid chromatography. Three categories of insect prothoracic glands were noted: a) those producing much more 3-dehydroecdysone than ecdysone; b) glands synthesizing almost equivalent amounts of each of these two ecdysteroids; c) prothoracic glands that yielded more ecdysone than 3-dehydroecdysone. In addition, the 3-oxoecdysteroid 3-reductase activity of the hemolymph of these insects was evaluated for its ability to convert 3-dehydroecdysone to ecdysone. The lepidopteran species tested yielded the most potent enzyme activity, although activity was demonstrated in members of other orders. These data indicate that the dehydroecdysone-ecdysone axis is not restricted to moths and butterflies. 相似文献
79.
H. Bussey C. Boone H. Zhu T. Vernet M. Whiteway D. Y. Thomas 《Cellular and molecular life sciences : CMLS》1990,46(2):193-200
Summary The K1 killer toxin ofSaccharomyces cerevisiae is a secreted, virally-coded protein lethal to sensitive yeasts. Killer yeasts are immune to the toxin they produce. This killer system has been extensively examined from genetic and molecular perspectives. Here we review the biology of killer yeasts, and examine the synthesis and action of the protein toxin and the immunity component. We summarise the structure of the toxin precursor gene and its protein products, outline the proteolytic processing of the toxin subunits from the precursor, and their passage through the yeast secretory pathway. We then discuss the mode of action of the toxin, its lectin-like interaction with a cell wall glucan, and its probable role in forming channels in the yeast plasma membrane. In addition we describe models of how a toxin precursor species functions as the immunity component, probably by interfering with channel formation. We conclude with a review of the functional domains of the toxin structural gene as determined by site-directed mutagenesis. This work has identified regions associated with glucan binding, toxin activity, and immunity. 相似文献
80.
TiO2光催化降解水体中抗生素的研究进展 总被引:1,自引:0,他引:1
本文综述了近十多年来多种不同抗生素在水体中的光催化降解行为,从水体中的抗生素的光催化降解环境影响因素,降解中间产物和降解途径,光催化降解动力学,光催化降解机理几个方面进行了阐述,展望了光催化降解水体中的抗生素类污染物的研究前景. 相似文献