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C Bailly J P Catteau N Helbecque J L Bernier R Houssin C Denis J P Hénichart 《Journal of inorganic biochemistry》1987,31(3):211-220
A model incorporating the metal chelating moiety of bleomycin and an anilinoacridine ring able to intercalate in DNA has been synthesized. The copper(II) complex of that molecule has been studied using circular dichroism and electron spin resonance by comparison with bleomycin. The introduction of the anilinoacridine ring involves a modification in the geometry of the complex. A distortion of the square-pyramidal form (type II complex) gives rise to a type I complex in which the metallic atom is drawn out of the plane of the four square-planar ligands and displaced slightly towards the fifth ligand. 相似文献
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Microbiological Degradation of Malodorous Substances of Swine Waste under Aerobic Conditions 总被引:2,自引:1,他引:1
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Denis Bourque Jean-Guy Bisaillon Rjean Beaudet M. Sylvestre Muhammad Ishaque Andr Morin 《Applied microbiology》1987,53(1):137-141
Phenol, p-cresol, and volatile fatty acids (VFA; acetic, propionic, isobutyric, butyric, isovaleric, and valeric acids) were used as odor indicators of swine waste. Aeration of the waste allowed the indigenous microorganisms to grow and degrade these malodorous substances. The time required for degradation of these substances varied according to the waste used, and it was not necessarily related to their concentrations. Using a minimal medium which contained one of the malodorous compounds as sole carbon source, we have selected from swine waste microorganisms that can grow in the medium. The majority of these microorganisms were able to degrade the same substrate when inoculated in sterilized swine waste but with an efficiency varying from one strain to the other. None of these strains was able to degrade all malodorous substances studied. Within 6 days of incubation these selected strains degraded the following: Acinetobacter calcoaceticus, phenol and all VFA; Alcaligenes faecalis, p-cresol and all VFA; Corynebacterium glutamicum and Micrococcus sp., phenol, p-cresol, and acetic and propionic acids; Arthrobacter flavescens, all VFA. On a laboratory scale, the massive inoculation of swine waste with C. glutamicum or Micrococcus sp. accelerated degradation of the malodorous substances. However, this effect was not observed with all of the various swine wastes tested. These results suggest that an efficient deodorization process of various swine wastes could be developed at the farm level based on the aerobic indigenous microflora of each waste. 相似文献
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Denis Roy Marco Lagimonire Marie-Jose Hardy Jean-Franois Bourassa Pierre Mourot 《Journal of biotechnology》1989,10(3-4):227-240
Factors affecting the viability and infectivity of an ectomycorrhizal fungus during moderate concentration by cross-flow filtration were determined. Mycelial suspensions were concentrated with three commercial membrane filters (Prostak Millipore Co., M14 Tech-Sep Co. and Ceraflo Norton Co.) under aseptic conditions. Medium components may reduce the filtration rate due to their low solubility. An antifoam agent did not reduce the average flux rates as much as did the malt extract. Clear unobstructed channels (I.D. 6mm) of the tubular modules (Tech-Sep) gave the best results both in terms of performance (filtration rate) and cell viability. Shear stresses caused by pumping and flow through narrow retentate channels were probably responsible for lowering viability and infectivity. There was no linear relationship between permeate fluxes and cell concentration. There is an optimum pore size both in terms of performance (filtration rate) and cell viability. Physical blockage of large pores by hyphae could explain lower permeate flux rates than those obtained with lower pore sizes membranes. 相似文献
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Barbara J. Wilcox Eric S. Corp Daniel M. Dorsa Dianne P. Figlewicz M. R. C. Greenwood Stephen C. Woods Denis G. Baskin 《Peptides》1989,10(6):1159-1164
Recent reports have suggested that the obesity and hyperphagia of the genetically obese Zucker rat may be related to defective insulin action or binding in the hypothalamus. We used quantitative autoradiography to determine if insulin binding is altered in specific hypothalamic nuclei associated with food intake. Insulin binding was measured in the arcuate (ARC), dorsomedial (DMN), and ventromedial (VMN) hypothalamic nuclei of 3–4-month-old lean (Fa/Fa) and genetically obese (fa/fa) Zucker rats. A consistently reproducible 15% increase in the total specific binding of 0.1 nM [125I]-insulin was found in the ARC of the obese genotype. A slight increase in insulin binding in the DMN was also found. No difference in specific insulin binding was found between genotypes in the VMN. Nonlinear least squares analysis of competitive binding studies showed that the Kd of the ARC insulin binding site was 33% higher in the lean rats than in the obese rats, indicating an increased affinity for insulin. No difference in site number (Bmax) was found in the ARC, DMN or VMN, and no evidence was found for reduced insulin binding in the hypothalamus of the obese (fa/fa) genotype. The results suggest that hyperphagia and obesity of the obese (fa/fa) Zucker rat genotype may be associated with increased insulin binding in the arcuate nucleus. 相似文献
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The effect of TPA (12-O-tetradecanoylphorbol-13-acetate) upon ionic exchanges was investigated in eggs of the sea urchin Arbacia lixula. Ouabain-sensitive 86Rb uptake and amiloride-sensitive 24Na influx were dramatically stimulated after TPA addition, indicating an enhancement of total ionic permeabilities. Stimulation by TPA of both Na+/H+ and Na+/K+ exchanges was canceled by amiloride, suggesting that activation of protein kinase C elicits, via Na+/H+ activity, stimulation of the sodium pump. However, TPA did not stimulate sodium pump activity and Na+/H+ exchange at the same rate as fertilization, probably because of an absence of calcium-dependent events. Further fertilization of TPA-pretreated eggs triggered an enhancement of sodium pump activity when the TPA treatment duration did not exceed 10 min. It is suggested that TPA activates preexisting transporting mechanisms in plasma membranes of unfertilized eggs (Na+ pump, Na+/H+ exchange) without eliciting corresponding regulatory mechanisms (Na+ stat, pH stat). 相似文献