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971.
Studies on the maintenance and expression of cloned DNA fragments in the nuclear genome of the green alga Chlamydomonas Reinhardtii 总被引:3,自引:0,他引:3
Anil Day Robert Debuchy Jeanette van Dillewijn Saul Purton Jean-David Rochaix 《Physiologia plantarum》1990,78(2):254-260
Using a biolistic device built here and based on the principle of the device described by Klein et al. (1987). we have reproducibly obtained transformants of Chlamydomonas reinhardtii . The reproducibility of the method has allowed us to examine the maintenance and expression of cloned DNA fragments introduced into C. Reinhardtii . 相似文献
972.
The classic Mallory-Cason staining procedure has been modified for application to sections "on tape" obtained from large deep frozen tissue specimens. These 20 microns cryosections are collected on tape from a large heavy duty cryomicrotome. The stained sections provide anatomical details that are not revealed by other techniques. The merit of this procedure is found in the support of modern medical modalities, both for research and educational purposes. 相似文献
973.
M. Koornneef T. D. G. Bosma C. J. Hanhart J. H. van der Veen J. A. D. Zeevaart 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1990,80(6):852-857
Summary In tomato, nine independent EMS-induced mutants representing recessive mutations at three different loci (gib-1, gib-2, and gib-3) were isolated. Six of these have an almost absolute gibberellin requirement for seed germination and elongation growth. In addition, the leaves are darker green, smaller, and changed in structure as compared to wild type. The three other mutants, which germinate without GA, are allelic to specific, nongerminating mutants and have less severe mutant characteristics. The respective loci are situated on three different chromosomes. The genes identified by these mutants control steps in gibberellin biosynthesis, as endogenous gibberellins are strongly reduced. 相似文献
974.
Two groups of 40 volunteers were given a dietary supplement consisting of 135 g of mackerel or meat (control) paste per day for 6 weeks. Compliance was about 80% in both groups and the daily intake of 20:5(n-3) and 22:6(n-3) from the mackerel supplement was about 1.3 and 2.3 g, respectively. In collagen-activated platelet rich plasma, the potency of blood platelet to produce HHT from arachidonic acid (AA) clearly reduced in the mackerel group, whereas the formation of HHTE from timnodonic acid (TA) increased slightly. Changes in the formation of HHT and HHTE, measured by HPLC, correlated significantly with those of TxB2 and TxB3, respectively, measured by GC/MS. Changes in the formation of the lipoxygenase products HETE (ex AA) and HEPE (ex TA) were qualitatively similar to that seen for the cyclo-oxygenase products, but quantitatively the responses were smaller. Formation of ir TxB2 in clotting blood significantly reduced in the mackerel group. In collagen-activated, citrated whole blood, TxB2 formation tended to be reduced in the mackerel-supplemented volunteers. Mackerel consumption was associated with the formation of considerable amounts of PGI3, as judged from the appearance of 2,3-dinor-delta 17-6-keto-PGF1 alpha in urine. The amount of the major metabolite of PGI2, 2,3-dinor-6-keto-PGF1 alpha was not reduced, or even increased. The daily amount of tetranor prostaglandin metabolites in the urine did not change significantly, which indicates that mackerel supplementation did not alter the formation of prostaglandins E and F. 相似文献
975.
L. S. van Overbeek J. D. van Elsas J. T. Trevors M. E. Starodub 《Microbial ecology》1990,19(3):239-249
One year after introduction into agricultural drainage waterPseudomonas fluorescens R2f (RP4),Pseudomonas putida CYM318 (pRK2501), andKlebsiella aerogenes NCTC418 (pBR322) could be recovered on agar media. Survival of the introduced strains depended on competition with the indigenous microflora, the presence of nutrients, and the availability of air.In contrast toK. aerogenes NCTC418 (pBR322), bothPseudomonas species lost their plasmids, as indicated by the consistently lower colony counts on selective medium compared with the counts on nonselective medium. The plasmid loss did not depend on nutrient status and oxygen supply.
P. fluorescens R2f cells could be detected with the immunofluorescence (IF) technique. Total cell counts determined by IF were consistently higher than corresponding colony counts. Even in samples where no colonies were recovered, R2f cells could be detected by IF. This indicated the occurrence of nonculturable R2f cells in drainage water. Homology with32P-labelled plasmid RP4 DNA was found in several drainage water samples that originally receivedP. fluorescens R2f (RP4), by using the cell suspension filter hybridization technique.
P. putida CYM318 andK. aerogenes NCTC418 cells could also be detected in sterile drainage water samples, after nonspecific staining with fluorescein isothiocyanate. Cell counts of both strains were consistently higher than corresponding plate counts. 相似文献
976.
Huub J. M. Op den Camp Claudius K. Stumm Gerben Straatsma Piet J. L. Derikx Leo J. L. D. van Griensven 《Microbial ecology》1990,19(3):303-309
The interaction betweenAgaricus bisporus andScytalidium thermophilum on agar media was studied by differential interference contrast and phase contrast microscopy.A. bisporus combatively replacesS. thermophilum in culture on agar media. The antagonistic effect ofA. bisporus is transmissible through a cellophane membrane and causes irreversible disintegration ofS. thermophilum protoplasm, resulting in a total loss of viability after prolonged interaction between the two fungi. On compost extract agar, but not on other media, the growth rate ofA. bisporus increased from 2.7 to 5.3 mm·d–1 following contact withS. thermophilum mycelium. 相似文献
977.
The anti-inflammatory compound d-ibuprofen has been investigated for anti-inflammatory and cyclooxygenase inhibitory activity in ocular inflammation induced by paracentesis of eyes of living rabbits. d-Ibuprofen is the dextro-rotary isomer of ibuprofen, a potent non-steroidal anti-inflammatory agent. Eyes pretreated topically with d-ibuprofen 0.8% showed a significant inhibition of aqueous protein (73.0%) and prostaglandin E2 (96.4%) increase after paracentesis as compared to paracentesized untreated fellow eyes and control eyes. In aqueous humor no significant correlation between the increase in prostaglandin E2 and protein could be established after paracentesis. These results indicate that d-ibuprofen could be a useful ocular anti-inflammatory agent as cyclooxygenase inhibitor. 相似文献
978.
979.
Actin Involvement in Exocytosis from PC12 Cells: Studies on the Influence of Botulinum C2 Toxin on Stimulated Noradrenaline Release 总被引:12,自引:1,他引:11
Botulinum C2 toxin is known to ADP-ribosylate actin. The toxin effect was studied on [3H]noradrenaline secretion of PC12 cells. [3H]Noradrenaline release was stimulated five- to 15-fold by carbachol (100 microM) or K+ (50 mM) and 10-30-fold by the ionophore A23187 (5 microM). Pretreatment of PC12 cells with botulinum C2 toxin for 4-8 h at 20 degrees C, increased carbachol-, K+-, and A23187-induced, but not basal, [3H]noradrenaline release maximally 1.5-to three-fold, whereas approximately 75% of the cellular actin pool was ADP-ribosylated. Treatment of PC12 cells with botulinum C2 toxin for up to 1 h at 37 degrees C also increased stimulated [3H]noradrenaline secretion, whereas toxin treatment for greater than 1 h decreased the enhanced [3H]noradrenaline release stimulated by carbachol and K+ but not by A23187. Concomitantly with toxin-induced stimulation of secretion, 20-50% of the cellular actin was ADP-ribosylated, whereas greater than 60% of actin was modified when exocytosis was attenuated. The data indicate that ADP-ribosylation of actin by botulinum C2 toxin largely modulates stimulation of [3H]noradrenaline release. Moreover, the biphasic toxin effects suggest that distinct mechanisms are involved in the role of actin in secretion. 相似文献
980.
Modulation of Ganglioside Biosynthesis in Primary Cultured Neurons 总被引:11,自引:4,他引:7
Murine cerebellar cells were pulse labeled with [14C]galactose, and the incorporation of radioactivity into gangliosides and neutral glycosphingolipids was examined under different experimental conditions. In the presence of drugs affecting intracellular membrane flow, as well as at 15 degrees C, labeled GlcCer was found to accumulate in the cells, whereas the labeling of higher glycosphingolipids and gangliosides was reduced. Monensin and modulators of the cytoskeleton effectively blocked biosynthesis of the complex gangliosides GM1, GD1a, GD1b, GT1b, and GQ1b, whereas incorporation of radioactivity into neutral glycosphingolipids, such as glucosylceramide and lactosylceramide, as well as GM3, GM2, and GD3 was either increased or unaltered. As monensin has been reported to interfere with the flow of molecules from the cis to the trans stacks of the Golgi apparatus, this result highlights at least one subcompartmentalization of ganglioside biosynthesis within the Golgi system. Inhibitors of energy metabolism affected, predominantly, the biosynthesis of the b-series gangliosides, whereas a reduced temperature (15 degrees C) more effectively blocked incorporation of radiolabel into the a-series gangliosides, a result suggesting the importance of GM3, as the principal branching point, for the regulation of ganglioside biosynthesis. 相似文献