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Gerard H. Markx Christopher L. Davey Douglas B. Kell Phillip Morris 《Journal of biotechnology》1991,20(3):279-290
A novel technique is described for the measurement of the volume fraction of biomass in a suspension by the simultaneous measurement of the conductivity of a suspension containing cells and of the medium in which the cells are suspended. The presence of non-conducting particulate matter in a suspension will cause the conductivity of a suspension to be decreased relative to that of the medium in which the particles are suspended. A simple equation (the Bruggeman equation) describes the relationship between the volume fraction of non-conducting particulate matter and the decrease in conductivity. The accuracy of this method for the determination of the biomass concentration of plant cells (Festuca arundinacea) in culture was shown. The method was successfully applied to the on-line determination of biomass concentrations during the growth of F. arundinacea cultures, and gave good agreement with biomass levels as determined from measurements of the radio-frequency dielectric permittivity of such cultures. 相似文献
23.
Jessica E. Hoogendijk Gerard W. Hensels Ina Zorn Linda Valentijn Emiel A. M. Janssen Marianne de Visser David F. Barker Bram W. Ongerboer de Visser Frank Baas Pieter A. Bolhuis 《Human genetics》1991,88(2):215-218
Summary Recently, it has been shown that Charcot-Marie-Tooth disease type 1a (CMT1a) is linked with a duplication of a DNA segment that is detected by probe VAW409R3, and that is located on chromosome 17p11.2. Here, we show that this duplication also contains VAW412R3a, but not A10-41 and EW503. Accounting for the duplication in recombination analysis, we found recombinants between CMT1a and EW301 and EW502, but not with A10-41, VAW409R3, and VAW412R3. Using pulsed-field gel electrophoresis analysis, we estimated the minimal size of the duplicated region in CMT1a patients to be 1100 kb. 相似文献
24.
The serum unsaturated vitamin B12-binding capacity (UBBC), unsaturated transcobalamin (UTC) I, UTC II, UTC III levels, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase activities and bilirubin concentration were estimated in 61 patients with liver diseases (31 with hepatoma, 30 with viral hepatitis). The levels of serum cobalamin, UTC I, UTC III, UBBC, alanine and aspartate aminotransferases, and bilirubin were raised in both hepatoma and viral hepatitis patients. Serum UTC II was reduced in both conditions. Alkaline phosphatase activity was significantly increased in hepatoma. Four significant correlations were observed among these parameters in the hepatoma patients while only one significant correlation was observed in viral hepatitis. 相似文献
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CNBr cleavage of unreduced proenzyme Clr yielded fragment CP2b, isolated by gel filtration and highpressure gel permeation chromatography. This fragment (˜ Mτ 55000) comprised at least 4 disulphidelinked peptides, which were separated by gel filtration after reduction and alkylation. Peptide CP2bRA4, overlapping the A- and B-chain regions in proenzyme Clr was digested by V8 staphylococcal protease, and the digest separated by reversed-phase HPLC. N-terminal sequence analysis of peptide CP2bRA4SP9 established that Clr activation involves the cleavage of a single Arg-Ile bond, located in the sequence: Gln-Arg-Gln-Arg-Ile-Ile-Gly-Gly 相似文献
27.
Dr. Gerard J. McGarrity Lindsay Gamon Theodor Steiner Joseph Tully Hitoshi Kotani 《Current microbiology》1985,12(2):107-112
Uridine phosphorylase activity has been used to detect mycoplasmas in cell cultures by measuring formation of14C-uracil from14C-uridine. In this report we show that all species ofMycoplasma, Acholeplasma, andUreaplasma tested exhibited uridine phorphorylase activity. Among the genusSpiroplasma, serogroups I-1, I-3, I-5, I-7, I-8, IV, XIII, and XIV lacked uridine phosphorylase activity.Present address: Ciba-Geigy, Basel, Switzerland. 相似文献
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Summary We have cloned the hisH tyrA wild-type genes of Bacillus subtilis with the aid of the chimeric plasmid pBJ194, which replicates both in B. subtilis and Escherichia coli. Primary cloning was done in E. coli. The original E. coli clone, carrying the recombinant plasmid (pGR1) which complements hisH tyrA mutants of B. subtilis, was selected directly from a mixture of plated E. coli clones by replicaplating these clones onto minimal agar plates without tyrosine spread just before with competent B. subtilis cells. After overnight incubation clusters of small colonies had developed exclusively in the E. coli [pGR1] colony prints.The Tyr+ minicolonies were shown to be B. subtilis carrying pGR1 because (i) their appearance depended linearly on the number of B. subtilis cells plated, (ii) they produced extracellular protease and amylase and (iii) plasmids could be reisolated from the minicolonies and used to transform B. subtilis recE4 tyrA1 both to Cmr and Tyr+.Plasmid pGR1 transfer through replica plating was compared with plasmid transfer in liquid. Both systems depended on transformable B. subtilis strains and were sensitive to DNAseI. However, whereas integration of the tyrA
+ gene into the chromosome and concomittant loss of plasmids occurred frequently during regular plasmid transformation of Rec+
B. subtilis, this was a rare event during plasmid transfer through replica plating. 相似文献
30.
Repair of UV damage in plasmid DNA by human fibroblasts 总被引:1,自引:0,他引:1
Hans Mooibroek Bauke de Jong Gerard Venema 《Molecular & general genetics : MGG》1984,195(1-2):175-179
Summary Plasmid DNA from Bacillus subtilis was introduced into monolayers of human fibroblasts by means of a modification of the calcium phosphate coprecipitation technique, comprising centrifugation of the coprecipitate onto the cells and treatment with polyethyleneglycol. The amount of DNA resistant to removal from the monolayers ranged from 10% to 15% of the input DNA. By determination of the biological activity of the plasmid DNA, re-extracted after various periods following entry into the fibroblasts and subsequently used as donor for B. subtilis protoplasts, it was shown that the activity of the plasmid DNA was gradually lost. When ultraviolet light-inactivated plasmid DNA was used as donor, reactivation of the plasmid was observed, which was completed within 2 h. The dose-dependent incorporation of [14C]-thymidine suggests that DNA repair processes were involved in reactivation of the plasmid DNA. 相似文献