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91.
The increasing complexity of biological problems and the increase of mathematical means to handle them on the one hand, and the possibility of automatized computation at the other, necessitate a revaluation of the present interactions between biology and mathematics; in this connection interrelations occur which can be divided into three kinds: mathematical biology, biological mathematics, and general biomathematics or methodology of the biomathematical sciences, by which are meant those scientific branches which arise from the said interactions. 相似文献
92.
No significant differences in the acetylene-reducing activity and evolution of H2 and CO2 nodulated roots ofPisum sativum inoculated with soilRhizobium populations from two soils with different acidities (Ruzyně soil 7.6; Lukavec soil 4.9) were observed.Rhizobium population from Lukavec soil formed nodules, exhibiting a higher H2 evolution. Co-inoculation with the Hup+ strain 128C30 (7×107 cells per seedling) eliminated, to some extent, the effect of soil populations on physiological activity.
Translated by Č. Novotny 相似文献
93.
Plasticity of the tobacco genome was studied by testing the DNAs of protoplast-derived regenerants with three different repetitive
DNA sequences by the method of quantitative DNA/DNA hybridizations. A large population of 91 regenerants belonging to 35 different
protoclones was analysed and a high degree of heterogeneity in the contents of the different DNA repeats was detected. The
contents of middle repetitive sequences of two types were more stable or changed in the same direction, while the highly repetitive
sequence varied independently and displayed a significant reduction in comparison with the two other sequences. Comparing
the variation within the subpopulations of plants of the same clonal origin and the variation among the protoclones led to
a conclusion that the pre-existing DNA variability in the starting plant material and/or thein vitro stress during the very early stages of protoclone regeneration played a decisive role in the formation of modified genomes
in regenerants. 相似文献
94.
Perin L. Donnini M. Diomede L. Romano M. Tacconi M. T. Luisetti M. Salmona M. 《Cytotechnology》1991,7(1):25-32
An expression vector for G-CSF, pASLB3-3, was constructed and introduced into Namalwa KJM-1 cells (Hosoi et al., 1988), and cells resistant to 100 nM of methotrexate (MTX) were obtained. Among them, the highest producer, clone SC57, was selected and the productivity of this clone was further characterized. The maximal production of G-CSF was at the most 1.8 g/ml/day using a 25 cm2 tissue culture flask, even though the cell number was above 7×105 cells/ml. The limiting factors at high density were analyzed as the deficiency of nutrients, such as glucose, cysteine and serine, and pH control. The depression of specific G-CSF productivity per cell under the batch culture conditions was overcome by using a perfusion culture system, BiofermenterTM (Sato, 1983) with modifications of nutrients supplementation by a dialysis membrane and/or dissolved oxygen (DO) supplementation by microsilicone fibers. ITPSGF medium was modified to elevate concentrations of amino acids and glucose by 2.0- and 2.5-times, respectively. Under the control of pH at 7.4 and DO at 3 ppm, the specific G-CSF productivity was not depressed even at high cell density (above 1×107 cells/ml), and the amount of G-CSF reached 41 g/ml. These results indicated the possibility of finding the optimum culture conditions for the production of recombinant proteins by Namalwa KJM-1 cells.Abbreviations ABTS
2,2-Azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid
- BSA
Bovine Serum Albumin
- BSA-PBS
Phosphate-buffered Saline without Ca2+ and Mg2+ containing Bovine Serum Albumin
- dhfr
Dihydrofolate Reductase
- DO
Dissolved Oxygen
- G-CSF
Granulocyte Colony-stimulating Factor
- HEPES
4-(2-Hydroxyethyl)-1-piperazineethansulfonic Acid
- IFN
Interferon
- MTX
Methotrexate
- PBS(-)
Phosphate-buffered saline without Ca2+ and Mg2+
- Tween-PBS
Phosphate-buffered saline without Ca2+ and Mg2+ containing 0.05% of Tween 20 相似文献
95.
J. Matoušek P. Dědič M. J. Beneš P. Kopáček Věra Turková Ludmila Trněná 《Biologia Plantarum》1990,32(6):460-473
A polyspecific antiserum against protein extracted from PSTV-infected tomato leaves was prepared and the IgGs were separated
by affinity chromatography on a beaded cellulose adsorbent with an immobilized “healthy” antigen. The antibody not adsorbed
entered into a preferential reaction with the antigen from PSTV-infected leaves as estimated by an enzyme-linked immunosorbent
assay. The immunochemical reactions did not significantly exceed the control background, if antigens from tomato leaves infected
with potato viruses X, Y and M were analyzed. By immunoblot technique we revealed, however, that several antigens not detected
in healthy leaves appeared in the leaves infected either with PSTV or with viruses X and M. An accumulation of a major antigen
having a molecular mass of about 70 kDa was observed in viroid-infected leaves only, suggesting the specificity for viroid
infection. The antigen was found not to be an alkaline endoproteinase - the pathogenesis-related protein P-69.
Some antigens with molecular masses approximately 38.0, 23.7 and 22 kDa, which occurred in PSTV-infected leaves and in healthy
calluses, were not detectable in PSTV-infected calluses.
No reaction exceeding the control level was observed using enzyme-linked immunosorbent assay for antigens from silver nitrate-treated
tomato leaves, although such leaves showed symptoms similar to that caused by viroids. 相似文献
96.
A lipopolysaccharide was isolated by extraction ofAspergillus flavus conidia with 45 % phenol at 68–70 °C. Quantitative analysis revealed 7 % nucleic acids, 5.5 % proteins, 46 % polysaccharides and 49 % lipids, of which 12 % were covalently bound. Glucose, mannose, galactose and fucose were detected as monosaccharide components of the polysaccharide moiety by gas chromatography; palmitic acid, stearic acid, oleic acid, linoleic acid and myristic acid were mainly present in the lipidic fraction. This material differs from the bacterial lipopolysaccharides, both in composition of the polysaccharide moiety and representation of fatty acids in the lipidic fraction. 相似文献
97.
98.
Ultrathin sectioning of submerged mycelium of Claviceps purpurea Tul. producing clavine alkaloids revealed yeast-like budding resulting in asexual sporesblastospores. These deciduous spores were born by extended hyphal cells and retained the same ultrastructure of cell organelles. Both the extended hyphae and the blastospores resembled the cells of ergot sclerotial tissue. A surface culture of C. purpurea Tul. producing no alkaloids was used as a reference. 相似文献
99.
Guno Haskå 《Microbial ecology》1975,1(1):234-245
Myxobacteria presumably produce extracellular bacteriolytic enzymes when they are growing in soil. In order to study their ecological significance, adsorption experiments were performed with lytic enzymes produced byMyxococcus virescens in casitone media. Different soils as well as montmorillonite and kaolinite can rapidly adsorb the bacteriolytic but not the proteolytic enzymes. About 1 gm of montmorillonite per liter of cell-free culture solution is enough for the adsorption of 97% of the bacteriolytic enzymes. The adsorption per unit weight is about 100 times greater on montmorillonite than on kaolinite. About 40% of the adsorbed enzymes can be eluted with solutions of high pH or high ionic strength. The only desorbed bacteriolytic enzyme is the alanyl-∈-N-lysine endopeptidase. 相似文献
100.
Staining of Some Specific Regions of Human Chromosomes,particularly the Secondary Constriction of No. 9 总被引:23,自引:0,他引:23
SEVERAL procedures have been described recently which produce specific patterns of differential staining in human chromosomes1–9. Techniques which involve DNA denaturation and reannealing reveal deeply stained areas on centromere and secondary constriction regions which have been equated with constitutive heterochromatin9. 相似文献