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Denis Williams 《BMJ (Clinical research ed.)》1964,2(5424):1554-1557
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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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Identification of interferon-gamma as the lymphokine that mediates leukotriene B4-induced immunoregulation 总被引:1,自引:0,他引:1
M Rola-Pleszczynski L Bouvrette D Gingras M Girard 《Journal of immunology (Baltimore, Md. : 1950)》1987,139(2):513-517
Leukotriene B4 (LTB4) has been shown to modulate lymphocyte responses in both a positive and a negative way, depending on the particular cell subsets it interacts with. Recent evidence also indicates that LTB4 can directly affect the production of cytokines such as interleukin 1 (IL 1) or interleukin 2 (IL 2) and interferon-gamma (IFN-gamma). In this report, we present evidence that human T cells pulsed with LTB4 modulate IL 1 production by human monocytes by secreting IFN-gamma. In fact, we found that LTB4-pulsed T cells were capable of inducing a suppression of lymphocyte proliferation if allowed to interact with monocytes, but that this suppression was reversed to an enhancing effect when monocytes were treated with the cyclooxygenase inhibitor indomethacin. Furthermore, LTB4-pulsed T cells released a soluble factor that would mediate both effects. This factor was found to be IFN-gamma, because affinity-purified IFN-gamma could reproduce the effects, and a rabbit polyclonal anti-serum to human IFN-gamma could block the activities of supernatants from LTB4-pulsed T cells. LTB4 was also shown to enhance IFN-gamma production by T4+ T cells and to inhibit IFN-gamma production by T8+ T cells. These results suggest that LTB4 may regulate immune cell functions by inducing IFN-gamma production by T4+ cells. 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