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1.
Ildikó Vidra Kálmán Simon László Institóris Ingeborg Csöregh Mátyás Czugler 《Carbohydrate research》1982,111(1):41-57
After hydrolysis of 1,6-dibromo-1,6-dideoxygalactitol (1) and 1,2:5,6-dianhydrogalactitol (2), 11 compounds were isolated, three of them as tritylated derivatives. Their structures were established on the basis of chemical evidence and, for four compounds, by X-ray diffraction. The main product of the hydrolysis of 1 was 3,6-anhydro-1-bromo-1-deoxy-dl-galactitol; the end-products of the hydrolysis of 2 were 1,5-anhydro-dl-galactitol, 2,5-anhydro-dl-altritol, and galactitol. 相似文献
2.
3.
Polytene salivary gland nuclei of Chironomus pallidivittatus were transplanted into oocytes of Xenopus laevis which were then cultured in vitro for 18 h. The giant chromosomes and nucleoli as well as the entire nuclei enlarged considerably
in volume during this time. The polyteny and specific chromomere pattern of the chromosomes were maintained, and the puffing
of the salivary gland-specific Balbiani rings was not noticeably changed. — Polytene nuclei from differentiated insect cells
transplanted into Xenopus oocytes thus appear suited for exposing giant chromosomes in vivo to purified factors such as regulatory molecules.
This paper is dedicated to Professor Wolfgang Beermann on the occasion of his 60th birthday 相似文献
4.
Fate of salmonellas and competing flora in meat sample enrichments in buffered peptone water and in Muller-Kauffmann's tetrathionate medium 总被引:1,自引:0,他引:1
H J Beckers J vd Heide U Fenigsen-Narucka R Peters 《The Journal of applied bacteriology》1987,62(2):97-104
Studies have been carried out in which growth patterns of a Salmonella sp. and competing micro-organisms, especially other Enterobacteriaceae, were followed during pre-enrichment in buffered peptone water (BPw) and subsequent selective enrichment in tetrathionate broth (TBB). Pre-enrichment cultures were inoculated with minced meat and three reference samples containing nalidixic acid-resistant salmonellas. Irrespective of their initial numbers in BPw, Enterobacteriaceae increased to 10(8)/ml or more. During incubation in TBB at 43 degrees C, numbers of lactose-positive Enterobacteriaceae decreased in most enrichments which resulted in a positive salmonella isolation, but remained constant in the majority of those that did not. Levels of lactose-negative Enterobacteriaceae did not decrease in most salmonella-positive tests, but did so in half of the salmonella-negative ones. In the salmonella-positive tests the numbers of salmonellas had increased to 10(3)-10(7)/ml in BPw and after transfer to TBB slowly reached 10(4)/ml or more. In all cases the numbers of salmonellas exceeded those of the competing flora on brilliant green agar (BGA). In the salmonella-negative tests the numbers of salmonellas had increased less in BPw and decreased in most of the TBB enrichments. In none of these negative tests did the numbers of salmonellas exceed those of the competing flora on BGA. Escherichia coli dominated in most of the salmonella-negative tests. The results suggest more influence of lactose-positive than lactose-negative Enterobacteriaceae on the detection of salmonellas. The effect of competing microorganisms seems to depend not only upon their initial numbers, but also upon the types that can interact with salmonellas during selective enrichment. 相似文献
5.
Remy B Baril G Vallet JC Dufour R Chouvet C Saumande J Chupin D Beckers JF 《Theriogenology》1991,36(3):389-399
Repeated administration of xenogenic gonadotropins in human or animal species may be responsible for antibody production and refractoriness. An experiment was conducted in which goats were treated with porcine FSH (p-FSH) at 6-week intervals for a period of 7 months. A sensitive radioimmunoassay (RIA) was used to detect antibodies to p-FSH in plasma samples taken at short-term intervals during a 7-month period. Antibodies appeared after the first injection, and levels increased following booster injections. A high correlation rate existed between antibody level and superovulatory response. Refractoriness in goats was associated with a high level of antibodies. 相似文献
6.
Phosphate-Activated Glutaminase in the Crude Mitochondrial Fraction (P2 Fraction) from Human Brain Cortex 总被引:1,自引:1,他引:0
Gerd Svenneby Bjørg Roberg Svein Hogstad Ingeborg Aa. Torgner Elling Kvamme 《Journal of neurochemistry》1986,47(5):1351-1355
The kinetics and other properties of phosphate-activated glutaminase have for the first time been studied in the crude mitochondrial fraction (P2 fraction) from human brain. The enzyme is for unexplained reasons inactivated postmortem. The enzyme activity decreases by storing the tissue or homogenate at 37 degrees C. The inactivation is not caused by formation of a dialysable inhibiting compound. No large proteolytic degradation has occurred, since the phosphate-activated glutaminase-like immunoreactive band did not disappear during the storage. The molecular weight of the subunit of the enzyme as determined by immunoblots of sodium dodecyl sulfate-treated homogenates from human brain is estimated to be approximately 64 K. The enzyme has been shown to have a pH optimum of 8.6; it is activated by phosphate, inhibited by glutamate, and partially inhibited by ammonia. Double-inverse plots of enzyme activity against phosphate are concave-upward, and more so in the presence of an inhibitor. The inhibition by glutamate appears to be noncompetitive with the substrate glutamine, and competitive with the activator phosphate. These kinetic properties are not significantly different from our earlier observations concerning phosphate-activated glutaminase from pig brain and pig kidney. 相似文献
7.
The amount of adenosine triphosphate (ATP) in human lymphocytes was determined using a technique based on light emission from a bioluminescent reaction with luciferin-luciferase. The amount of ATP changed when cells were incubated in the presence of specific HLA antisera and complement. For determination of intracellular ATP a modified method was applied, which was based on reduction of extracellular ATP by the addition of ATPase. The results of titration of an anti-human lymphocyte serum using the bioluminescence assay were in agreement with the results of fluorescence vitality staining. Bioluminescent HLA-determination in 57 cell samples each tested with 5 different antisera also gave good agreement (95.8%) with the conventional method. From these experimental data the calculated ATP content per lymphocyte was 0.135 ± 0.058 pg ATP. 相似文献
8.
Collaborative study on the isolation of salmonella from artificially contaminated milk powder 总被引:1,自引:0,他引:1
H J Beckers F M van Leusden D Roberts O Pietzsch T H Price M van Schothorst P D Tips P Vassiliadis E H Kampelmacher 《The Journal of applied bacteriology》1985,59(1):35-40
The suitability of artificially contaminated milk powder as a substrate for salmonella reference samples and its stability under different storage conditions were studied. The need for a reconstitution step in the standard isolation method for salmonellas from milk powders was also investigated. When milk powder was examined in this way with a reconstitution step, differences in laboratory methods and/or storage times had no significant effect on the results after storage at 4 degrees C. With powder stored at room temperature there was a systematic decrease in the number of samples positive as the storage time increased. It is concluded therefore that milk powder contaminated with salmonellas should be stored at 4 degrees C. Examination of such milk powder with a reconstitution step yielded better results than without it and this step is therefore necessary for improving the reproducibility of the method. No significant differences were encountered between the standard isolation method and that used in the authors' laboratories. The results of this study indicate that milk powder is suitable as basic material for reference samples and that a reconstitution step should be included in the standard salmonella isolation procedure. 相似文献
9.
1. Two acid phosphatases (β-glycerophosphatase and phenylphosphatase), acid β-glucuronidase and cathepsin were demonstrated in the 0·25m-sucrose homogenates from whole calf thyroid tissue and from isolated calf thyroid cells. 2. The main kinetic characters of these enzymes were studied. 3. All these acid hydrolases are partially sedimentable and display a latency that is unmasked by treatment with Triton X-100 and on dilution in hypo-osmotic media. It is concluded that these acid hydrolases belong to the lysosomes. 相似文献
10.