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41.
Elizabeth R. Fielding David B. Archer Everly Conway de Macario Alberto J. L. Macario 《Applied microbiology》1988,54(3):835-836
Methanogenic bacteria were isolated from landfill sites in the United Kingdom. Strains of Methanobacterium formicicum, Methanosarcina barkeri, several different immunotypes of Methanobacterium bryantii, and a coccoid methanogen distinct from the reference immunotypes were identified. 相似文献
42.
Summary A simple device is described for con-trolled feeding of pasty materials in laboratory scale fed-batch cultures. The device
was tested with apple pomace as raw material for production of microbial biomass, using the level of dissolved oxygen as controlled
parameter. 相似文献
43.
Dr. Alfonso Ruiz-Bravo María Jimenez-Valera Gerardo Alvarez de Cienfuegos Khalil Kouwatli Alberto Ramos-Cormenzana 《Current microbiology》1986,13(6):313-316
Twelve strains ofYersinia enterocolitica were examined for their ability to bind spontaneously to murine leukocytes. Each of eight HeLa cell invasive strains exhibited nonselective binding to peritoneal leukocytes, lymph node leukocytes, and thymocytes, whereas four noninvasive strains lacked binding properties. Like the HeLa cell invasion, the binding ofY. enterocolitica to leukocytes was much less efficient for bacteria grown at 37°C than for bacteria grown at 22°C. The binding properties were not influenced by the virulence plasmid that codes for Vwa+ phenotype. This leukocyte binding test is proposed as a simple assay for invasive properties ofY. enterocolitica. 相似文献
44.
Jorgina Satrustegui Juan Bautista Alberto Machado 《Molecular and cellular biochemistry》1983,51(2):123-127
Summary The utilization by yeast of two carbon sources is carried out through the operation of the glyoxylic acid cycle. Kinetic data from the isocitrate transforming enzymes suggest that the flow of isocitrate through the glyoxylic acid cycle depends upon the inhibition of the isocitrate decarboxylating enzymes. Both isocitrate dehydrogenases are inhibited by a mixture of glyoxylate + oxaloacetate, but for the reasons described in the text we consider that this inhibition is of no physiological significance. On the other hand, we have found that NADPH is a competitive inhibitor of NADP-isocitrate dehydrogenase with respect to NADP+, with a KI similar to its KM. It also produces an additive effect on the NADH-produced inhibition of NAD-isocitrate dehydrogenase. We propose NADPH as the compound that channels the utilization of isocitrate into the glyoxylic acid cycle. This is supported by the finding of an increased NADPH/NADP+ ratio in acetate grown yeast with respect to glucose grown cells. 相似文献
45.
Ana Rosa Santa Cruza Luis A. Quesada Allue Alberto Baldi 《Molecular and cellular biochemistry》1983,56(1):55-66
Microsomal preparations from malignant human breast tumors catalyzed the transfer of mannose and glucose from GDP-[14C]-Man and UDP-[14C]-Glc into lipid-linked sugars and glycoprotein-like substances. As judged by several criteria the obtained lipid-linked monosaccharides behaved as dolichyl phosphate mannose and dolichyl phosphate glucose whereas lipid-linked oligosaccharides behaved as polyprenyl diphosphate derivatives. The optimum conditions for mannosyl- and glucosyl-transfer reactions and the effect of dolichyl phosphate, detergent and EDTA on incubation mixture were described. 相似文献
46.
Summary The development of a synthetic medium that supports growth and differentiation of insect embryonic tissues afforded the possibility
of studying the interactions between nerve and other cell types in long term cultures. The mechanical dissociation of embryonic
nerve tissues results in survival of nerve cells but not of glial cells. The dissociated glial-free neurons produce a dense
fibrillar network in the presence, but not in the absence, of foregut explants or other tissues from same donors. Nerve fiber
bundles outgrowing from dissociated neurons enter foregut segments and establish synaptic connections with muscle cells. Foregut
explants undergo differentiation and become contractile in long term cultures when innervated by dissociated nerve cells.
The progressive deterioration of similar foregut tissues cultured alone contrasts with the excellent condition of innervated
explants and suggests that this is due to trophic factors released by nerve fibers. The same in vitro systems provided the
opportunity of studying the interaction between nerve fibers produced by the autonomic ingluvial ganglion, which adheres to
the surface of the alimentary tract, and muscle cells. Multiple esophagus explants from cockroach embryos become interconnected
by fibers emerging from ingluvial ganglia, when the explants are combined in vitro at short distance from each other. Muscle
cells migrating from the esophagi line up on axons branching out in the medium, or form contractile ribbons which, in turn,
establish connections with nerve fibers. The thigmotropism of muscle cells and strong affinity for nerve fibers reveal a new
aspect of muscle cells-to-fibers interaction, amenable to further analysis in vitro.
This work was supported in part by United States Public Health Service grant NS-03777 and grant GB-16330 X from the National
Science Foundation 相似文献
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The Lotka-Volterra competition model was used to represent the interaction between Laurencia obtusa and Hypnea spinella. A new model that considers effects of competition on algal carrying capacity is suggested. To test the models, data from field experiments conducted in an intertidal region at Cabo Frio Island, Rio de Janeiro, Brazil, were used. Both models showed that Hypnea was a stronger competitor than Laurencia. The model of interaction through the carrying capacity showed a stable coexistence between the algal populations and better represented the experimental data. 相似文献