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161.
The plasmid vector pEM100 (13.5 kb) constructed from pGV1106, a miniderivative of the broad-host-range IncW pSa plasmid, and
the pAM330 plasmid ofBrevibacterium lactofermentum is not stably maintained inEscherichia coli host cells under nonselective growth conditions. By insertion of a 0.9 kb DNA fragment containing theparB locus (responsible for the maintenance of plasmid R1 inE. coli cells) to plasmid pEM100, plasmid pEM110 was prepared which is maintained in a population ofE. coli cells growing without a selection pressure very stably.
Translated by Č. Novotny 相似文献
162.
The present paper describes isolation and purification ofa-hemolysin ofEscherichia coli. The optimum production medium was found to be the Todd—Hewitt broth. Out of thirteen fractions obtained after separation
on Sephadex G-200, two fractions possessed the highest relative specific activity. 相似文献
163.
František Blahák Tat'ána Jeništová Ivana Divišová 《International journal of biometeorology》1992,36(3):125-129
Effects of atmospheric frontal passages on intraocular pressure (IOP) in patients with open-angle glaucoma are statistically investigated to show the meteorotropism of this disease. Changes in IOP caused by frontal passages are evident; the response is not identical in all the patients near the day of the passage of a warm front, while on the third day following the passage of the front a well pronounced drop in IOP occurs. Anomalous increases of IOP over several months' duration occurred in the years 1986–7. This finding is explained in relation to the hypothesis of environmental contamination in Central Europe by radioactive cesium nuclides due to the Chernobyl accident. 相似文献
164.
Human T-cell leukemia virus type I envelope protein maturation process: requirements for syncytium formation. 总被引:4,自引:2,他引:2
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The human T-cell leukemia virus type I (HTLV-I) envelope protein is synthesized as a gp61 precursor product cleaved into two mature proteins, a gp45 exterior protein and a gp20 anchoring the envelope at the cell membrane. Using N-glycosylation inhibitors and site-directed mutagenesis of the potential glycosylation sites, we have studied the HTLV-I envelope intracellular maturation requirements for syncytium formation. We show here that experimental conditions resulting in the absence of precursor cleavage (tunicamycin, monensin treatments, and use of inhibitors of the reticulum steps of the N glycosylations) also result in no cell surface expression of envelope protein. The lack of syncytium formation observed in these cases is thus explained by incorrect intracellular transport. When the precursor is cleaved in the Golgi stack (no treatment or treatment with inhibitors of the Golgi steps of the N glycosylations), it is transported to the cell surface in all the cases examined. Syncytium formation is markedly reduced, however, when Golgi glycosylations are incorrect, which shows that the sugar moieties are involved in the envelope functions. Site-directed mutagenesis demonstrates that each of the five potential glycosylation sites is actually glycosylated. Glycosylation of sites 1 and 5 is required for normal maturation, whereas that of sites 2, 3, and 4 is dispensable. Glycosylation of each site, however, is required for normal syncytium formation. Altogether, the restraints exerted by the cell for the HTLV-I envelope to be transported and functional are very high, which might play a role in the observed conservation of the envelope amino acid sequence between various strains. 相似文献
165.
J. T. P. Albrechtová J. Ullmann J. Krekule A. Blažková I. Machžčková Z. Vondráková J. Blažková S. Procházka V. Borkovec D. A. Baker F. Didehvar Z. Tesařová V. Czaková M. Zima K. Doležal T. Doleželová V. Psota M. Dundelová V. Reinöhl S. Prochàzka J. Mikulík M. Dvořěk J. Černohorskě O. Auxtová B. Cholvadová D. Lišková M. Kubačková S. Karácsonyi L. Bilisics 《Biologia Plantarum》1992,34(1):569-587
166.
The effect of two Bradyrhizobium japonicum strains (D344 and Urbana), on the frequency and intensity of infection by a VAM fungal Glomus sp. and the effect of VAM on biomass production by nodulating plants were tested in soybean growing in a soil containing low levels of accessible P and N. During the initial stage of vegetative growth, mycorrhiza frequency in roots inoculated with the two rhizobial strains did not differ. However, during flowering it was 178% higher in roots with the strain D344 than in the presence of the strain Ubrana. At final harvest (green pods) the VAM frequency did not differ in the presence of either strain. VAM positively affected biomass production, foliar concentrations of P, Zn and Cu, and number and dry matter yield of pods, but did not increase concentrations of total N and K. In nonmycorrhizal plants total nitrogenase activity (not nodule mass) and growth were higher with the rhizobial strain Urbana. The greatest nitrogenase activity, growth and yield occurred in the presence of the VAM fungus, and did not differ for plants with different strains of rhizobia. 相似文献
167.
Summary The formation of 10 g polyols/L (glycerol, arabitol, xylitol) during L-lactic acid synthesis byRhizopus arrhizus was observed. Consumption of polyols after glucose exhaustion was discovered resulting in a subsequent rise in the lipid content of the mycelium. Lactate utilization was not detected. 相似文献
168.
Darja Barlič Maganja Borut Štrukelj Jože Pungerčar Franc Gubenšek Vito Turk Igor Kregar 《Plant molecular biology》1992,20(2):311-313
A genomic DNA clone encoding an aspartic proteinase inhibitor of potato was isolated from a lambda EMBL3 phage library using the aspartic proteinase inhibitor cDNA as a hybridization probe. The gene has all characteristic sequences normally found in eucaryotic genes. Typical CAAT and TATA box sequences were found in the 5-upstream region. In this part are also two putative regulatory AGGA box sequences located. In the genomic sequence there are no intron sequences interrupting the coding region. An open reading frame of the gene encodes a precursor protein of 217 amino acids which shows high percent identity with the aspartic proteinase inhibitor cDNA. 相似文献
169.
170.
21-day old plants ofChenopodium rubrum L. ecotype 374 were used. Organ relationships in the shoots were investigated by32P distribution, which indicated different organ correlations in plants grown in continuous light and in plants treated with
flower-inducing and non-inducing dark periods. Dark periods were associated with a low32P distribution in young leaves and a high one in axillary buds. In the following light period the high32P distribution in axillary buds continued whereas the32P distribution in the leaves on the main axis increased and was similar to that in plants grown in continuous light. The high32P distribution in axillary buds was brought about by both, flower-inducing and non-inducing dark treatments. Decapitation
resulted in a high32P distribution in buds, in continuous light an increased32P distribution was also found in leaves. These effects were not fully cancelled by IAA application.
The results are discussed with respect to an assumption that decrease of apical dominance represents a step in a sequence
of events leading to flowering. 相似文献