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961.
Summary A formalin—calcium fixation method of preparing cryosections is described, which allows demonstration of Langerhans' cells by S100 antigen staining on frozen sections. The number of Langerhans' cells given by T6 antigen staining is also higher in formalin—calcium fixed frozen sections than acetone fixed frozen sections. The preparation is suitable for dual demonstration of the two antigens on the same section enabling a more accurate numerical evaluation of Langerhans' cell populations in the normal cervical epithelium. 相似文献
962.
Stanley A. Vinores Mary M. Herman Lucien J. Rubinstein 《The Histochemical journal》1987,19(8):439-448
Summary Neuron-specific () enolase, a glycolytic enzyme used as a relatively specific marker for normal neurons and neuroendocrine cells, has recently been found in a variety of neoplastic cells and in reactive astrocytes. Its localization was investigated by immunohisto- and electron-immunocyto-chemistry, in the proliferating supportive Schwann cells of a peripheral ganglioneuroblastoma and in the neoplastic Schwann cells of four acoustic tumours. By light microscopy, the neoplastic Schwann cells showed moderate uneven diffuse immunopositivity for enolase. By electron-immunocy-tochemistry, both types of Schwann cells demonstrated immunopositivity discretely limited to their cell surface membranes. The neoplastic ganglion cells and axons of the ganglioneuroblastoma and the normal neurons and axons included in the schwannomas were, as expected, intensely immunopositive. The visualization of enolase on the cell surface membranes of both neoplastic and non-neoplastic proliferating Schwann cells suggests that increased glycolytic activity may occur on the surface of these proliferating cells irrespective of the nature of the proliferation. 相似文献
963.
L. Vitaioli E. Baldoni L. Bellini A. Pederzoli L. Bolognani 《The Histochemical journal》1987,19(2):85-93
Summary The presence of arylsulphatase A and cerebroside sulphates in different tracts ofRana esculenta oviduct during different phases of the reproductive cycle were investigated by histochemical and biochemical procedures. The results indicate that enzyme activity shows seasonal fluctuations connected with the phase of the sexual cycle. The concentrations of cerebroside sulphates (the natural substrates of arylsulphatase A) is related to the activity of this hydrolytic enzyme. The role of arylsulphatase A activity in regulating the substrate concentration, and particularly that of sulphatides, is discussed. 相似文献
964.
Summary Bicarbonate-stimulated Mg2+ dependent ATPase activity was demonstrated both biochemically and cytochemically, in brush border membranes from rat, rabbit and guinea pig duodenum. There was no correlation between enzyme activity and basal HCO
3
-
secretion rates in the different species. The concentration of HCO
3
-
necessary for optimal stimulation of ATPase activity, degree of stimulation and total activity was higher in the rat than in other species. Activity was higher in rat duodenum than in the ileum. This is consistent with the proposed electrogenic HCO
3
-
secretion in the duodenum. Distribution of activities of alkaline phosphatase and HCO
3
-
-stimulated Mg2+-ATPase along the duodenal villus showed significant differences, suggesting that the two activities reflect, at least in part, distinct enzymes. 相似文献
965.
Chromosome Specificity of Polysomy Promotion by Disruptions of the Saccharomyces cerevisiae RNA1 Gene 总被引:2,自引:1,他引:1 下载免费PDF全文
Previously, we showed that a disruption of the yeast RNA1 gene with LEU2 sequences promotes polysomy for chromosome XIII. Here we demonstrate that this phenotype is due to sequences specific to the RNA1 gene and that the disruption allele does not affect nondisjunction of three other chromosomes or polysomy of a minichromosome. Hence polysomy appears to be restricted to chromosome XIII. 相似文献
966.
A New Non-Mendelian Genetic Element of Yeast That Increases Cytopathology Produced by M1 Double-Stranded RNA in ski Strains 总被引:6,自引:0,他引:6 下载免费PDF全文
The Saccharomyces cerevisiae SKI (superkiller) genes are repressors of replication of M, L-A, and L-BC double-stranded (ds) RNAs; ski strains have an increased M dsRNA copy number and, as a result, are cold-sensitive for growth at 8 degrees. Growth is normal, however, at higher temperatures. We have found a new cytoplasmic genetic element [D] (for disease) that makes M1 dsRNA-containing superkiller strains grow slowly at 30 degrees, not at all at 37 degrees, and only very poorly at 20 degrees. These growth defects require three factors: a chromosomal ski mutation, the presence of M1 dsRNA, and the presence of the new cytoplasmic factor, [D]. We have isolated mutants unable to maintain [D] (mad), at least one of which is due to mutation of a single chromosomal locus. Further, [D] can be cured by growth at 37-39 degrees. We present evidence that [D] is not M, L-A, L-BC or W dsRNAs or mitochondrial DNA, 2 mu DNA, or [psi], but [D] depends on L-A for its maintenance. We also show that [D] is distinct from [B], a cytoplasmic element that allows M1 dsRNA to be stably replicated and maintained in spite of defects in certain chromosomal MAK genes that would otherwise be necessary. [D] activity is blocked by the presence of another extrachromosomal element, called [DIN] (for [D] interference). [D] and [DIN] may be different natural variants of the same molecule. 相似文献
967.
Recalibration of the Pseudomonas aeruginosa Strain Pao Chromosome Map in Time Units Using High-Frequency-of-Recombination Donors 总被引:16,自引:0,他引:16 下载免费PDF全文
High-frequency-of-recombination donors of P. aeruginosa strain PAO were generated using a temperature-sensitive, replication mutant of the IncP-1 plasmid R68, loaded with the transposon Tn2521. Fourteen donors so isolated mobilized the chromosome in a polarized manner from a number of different transfer origins. The donors were used to construct a time of entry map of the entire chromosome and this was achieved by determining the time of entry of 32 randomly dispersed markers in crosses using nalidixic acid to interrupt chromosome transfer. Analysis of the time of entry data enabled the recalibration of the chromosome map to 75 min. 相似文献
968.
Carolyn J. P. Jones Sally M. Mosley Iona J. M. Jeffrey R. W. Stoddart 《The Histochemical journal》1987,19(5):264-268
Summary A simple procedure is described for eliminating non-specific staining with avidin—peroxidase conjugates. Murine ovaries were embedded in either paraffin wax or epoxy resin and, after blocking endogenous peroxidase activity, were treated with 10 µg/ml biotinylatedPisum sativum agglutinin. Avidin—peroxidase conjugates (5 µg/ml), diluted in standard 0.05m tris-buffered saline, pH 7.6, containing 0.139m NaCl, produced considerable background coloration and intense mast cell staining in controls without the lectin. This background diminished as the ionic strength of the buffer was raised. At 0.125m Tris-buffered saline (containing 0.347m NaCl) the background was completely unstained, with elimination of all binding to mast cells and only minimal loss of specific lectin binding. 相似文献
969.
Summary The effects of formaldehyde, glutaraldehyde, methanol, Clarke's fixative and microwave irradiation on the quantitative staining of proteins (Naphthol Yellow S) and nucleic acids (Ethyl Green—Pyronin) in a cell culture system have been investigated. Overall, glutaraldehyde rapidly yielded the highest and most consistent levels of staining when compared to all other chemical fixatives. Although microwave irradiation was found to be uneven, 4 min exposure to 700W was found to give higher levels of protein staining than those achieveable with glutaraldehyde. Time-dependent processes were observed with all procedures. In addition, dissociations in the trends of protein and nucleic acid staining were observed. It is suggested that these results domonstrate fixation events that have not previously been resolved from the effects of reagent penetration into tissue blocks. 相似文献
970.
Summary The purpose of this paper is to describe the immunocytochemical localization of M protein of vesicular stomatitis virus (VSV) in infected cells. Vero cells, MDBK cells, Swiss 3T3 cells, and BHK cells were examined at various times after infection. For immunofluorescent staining, the cells were fixed with PLP fixative and then treated with 0.05% Triton X-100 before incubation with antibodies. Three hours after infection, M protein exhibited diffuse immunostaining throughout the cytoplasm and later accumulated along the cell membrane. The localization of M protein differed from the granular localization of the nucleocapsid N protein of VSV in the cytoplasm. For electron microscopy, the cells were fixed first in a mixture of 2% paraformaldehyde and 0.05% glutaraldehyde and then with PLP fixative, this being followed by treatment with 0.05% saponin. They were then immunostained using the immunoperoxidase method. The M protein was found to be distributed throughout the cytoplasm and later under the cell membrane, especially at virus budding sites. We also used postembedding immunostaining and freeze-fracture immunostaining to avoid the translocation of M protein caused by the detergent treatment. These techniques confirmed our previous results. Our findings are consistent with the view that the M protein of VSV is synthesized on free ribosomes and is then associated with the cell membrane where viral assembly may occur.S. Ohno was a visiting fellow from the Fogarty International Center at the National Institutes of Health, USA, from September 1981 to August 1983, while some parts of this work were in progress. 相似文献