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1.
Isolation and characterization of plasma membrane-associated cortical granules from sea urchin eggs 总被引:9,自引:6,他引:3 下载免费PDF全文
Cortical granules, which are specialized secretory organelles found in ova of many organisms, have been isolated from the eggs of the sea urchins Arbacia punctulata and Strongylocentrtus pupuratus by a simple, rapid procedure. Electron micropscope examination of cortical granules prepared by this procedure reveals that they are tightly attached to large segments of the plasma membrane and its associated vitelline layer. Further evidence that he cortical granules were associated with these cell surface layers was obtained by (125)I-labeling techniques. The cortical granule preparations were found to be rich in proteoesterase, which was purified 32-fold over that detected in a crude homogenate. Similarly, the specific radioactivity of a (125)I-labeled, surface glycoprotein was increased 40-fold. These facts, coupled with electron microscope observations, indicate the isolation procedure yields a preparation in which both the cortical granules and the plasma membrane-vitelline layer are purified to the same extent. Gel electrophoresis of the membrane-associated cortical granule preparation reveals the presence of at least eight polypeptides. The major polypeptide, which is a glycotprotein of apparent mol wt of 100,000, contains most of the radioactivity introduced by (125)I-labeling of the intact eggs. Lysis of the cortical granules is observed under hypotonic conditions, or under isotonic conditions if Ca(2+) ion is present. When lysis is under isotonic conditions is induced by addition of Ca(2+) ion, the electron-dense contents of the granules remain insoluble. In contrast, hypotonic lysis results in release of the contents of the granule in a soluble form. However, in both cases the (125)I-labeled glycoprotein remains insoluble, presumably because it is a component of either the plasma membrane or the vitelline layer. All these findings indicate that, using this purified preparation, it should be possible to carry out in vitro studies to better define some of the initial, surface-related events observed in vivo upon fertilization. 相似文献
2.
1. U7 snRNP particles were bound in vitro to H4 pre-mRNA using immunoassay experiments. 2. The processing of in vitro H4 pre-mRNAs is an SmRNP-dependent reaction. 3. U7 RNA was isolated as a unique species from the complex H4-pre-mRNA-snRNPs, which indicates its involvement in the processing of histone pre-mRNAs. 相似文献
3.
To elucidate the role of dopamine as a neuromediator in the adrenocorticotropic hormone (ACTH) secretion, investigations were carried out with dopaminergic pharmacology drugs on male white Wistar rats. In the first series of experiments, the effects of 200 mg/kg body wt L-DOPA, of the combination of 200 mg/kg L-DOPA and 50 mg/kg body wt carbidopa, and of 2.5 mg/kg body wt bromocriptine, after a single intraperitoneal injection of ACTH in the serum of rats after 30, 90 and 120 min, following the injection, were studied. In the second series of experiments, the effect of 200 mg/kg body wt L-DOPA, of the combination of 200 mg/kg body wt L-DOPA and 50 mg/kg body wt carbidopa, of 1 mg/kg body wt bromocriptine, after intraperitoneal injection, on the concentration of ACTH in the serum within 7 days, were assessed. The inhibition of agonists of dopamine after ACTH secretion with repeated application has been shown. Using a radioimmunology assay with test kits, the amount of ACTH in the serum was determined. 相似文献
4.
Pironcheva G 《Cytobios》1998,95(380):167-171
Saccharomyces cerevisiae (ale strain) grown in batch culture to stationary phase was tested for its tolerance to heat (50 degrees C for 5 min), hydrogen peroxide (0.3 M) and salt (growth in 1.5 M sodium chloride/YPD medium). Yeast cells which have been exposed previously to heat shock are more tolerant to hydrogen peroxide and high salt concentrations (1.5 M NaCl) than the controls. Their fermentative activity as judged by glucose consumption and their viability, as judged by cell number and density have higher levels when compared with cells not previously exposed to heat shock. Experimental conditions facilitated the isolation of S. cerevisiae ale strain, which was tolerant to heat, and other agents such as hydrogen peroxide and sodium chloride. 相似文献
5.
Phylogenetic utility of the nuclear gene arginine decarboxylase: an example from Brassicaceae 总被引:10,自引:2,他引:8
Arginine decarboxylase (ADC) is an important enzyme in the production of
putrescine and polyamines in plants. It is encoded by a single or low-copy
nuclear gene that lacks introns in sequences studied to date. The rate of
Adc amino acid sequence evolution is similar to that of ndhF for the
angiosperm family studied. Highly conserved regions provide several target
sites for PCR priming and sequencing and aid in nucleotide and amino acid
sequence alignment across a range of taxonomic levels, while a variable
region provides an increased number of potentially informative characters
relative to ndhF for the taxa surveyed. The utility of the Adc gene in
plant molecular systematic studies is demonstrated by analysis of its
partial nucleotide sequences obtained from 13 representatives of
Brassicaceae and 3 outgroup taxa, 2 from the mustard oil clade (order
Capparales) and 1 from the related order Malvales. Two copies of the Adc
gene, Adc1 and Adc2, are found in all members of the Brassicaceae studied
to data except the basal genus Aethionema. The resulting Adc gene tree
provides robust phylogenetic data regarding relationships within the
complex mustard family, as well as independent support for proposed tribal
realignments based on other molecular data sets such as those from
chloroplast DNA.
相似文献
6.
Annerieke C van Groenestijn Ingrid GL van de Port Carin D Schröder Marcel WM Post Hepke F Grupstra Esther T Kruitwagen Harmen van der Linde Reinout O van Vliet Margreet GH van de Weerd Leonard H van den Berg Eline Lindeman 《BMC neurology》2011,11(1):1-11
Background
Neuropathic pain must be correctly diagnosed for optimal treatment. The questionnaire named Neuropathic Pain Symptom Inventory (NPSI) was developed in its original French version to evaluate the different symptoms of neuropathic pain. We hypothesized that the NPSI might also be used to differentiate neuropathic from non-neuropathic pain.Methods
We translated the NPSI into German using a standard forward-backward translation and administered it in a case-control design to patients with neuropathic (n = 68) and non-neuropathic pain (headache and osteoarthritis, n = 169) to validate it and to analyze its discriminant properties, its sensitivity to change, and to detect neuropathic pain subgroups with distinct profiles.Results
Using a sum score (the NPSI-G score), we found sensitivity to change (r between 0.37 and 0.5 for pain items of the graded chronic pain scale) and could distinguish between neuropathic and other pain on a group basis, but not for individual patients. Post hoc development of a discriminant score with optimized diagnostic properties to distinguish neuropathic pain from non-neuropathic pain resulted in an instrument with high sensitivity (91%) and acceptable specificity (70%). We detected six different pain profiles in the patient group with neuropathic pain; three profiles were found to be distinct.Conclusions
The NPSI-G potentially combines the properties of a diagnostic tool and an instrument to identify subtypes of neuropathic pain. 相似文献7.
8.
Differences in the mRNA species were observed when cDNA complementary to HnRNA from normal liver was hybridized with mRNA from hepatocellular carcinoma induced by aflatoxin B1. The hybridizations between cDNA complementary to HnRNA from liver cell carcinoma and HnRNA from normal liver indicate that there is homology between their sequences. The findings in this paper suggest that mRNA species normally restricted to the cell nucleus are present in the cytoplasm of liver carcinoma cells. 相似文献
9.
Ricci GC De Souza-Kaneshima AM Felismino MF Mendes-Bonato AB Pagliarini MS Do Valle CB 《Journal of genetics》2011,90(2):289-294
A total of 44 accessions of Brachiaria decumbens were analysed for chromosome count and meiotic behaviour in order to identify potential progenitors for crosses. Among them,
15 accessions presented 2n = 18; 27 accessions, 2n = 36; and 2 accessions, 2n = 45 chromosomes. Among the diploid accessions, the rate of meiotic abnormalities was low, ranging from 0.82% to 7.93%. In
the 27 tetraploid accessions, the rate of meiotic abnormalities ranged from 18.41% to 65.83%. The most common meiotic abnormalities
were related to irregular chromosome segregation, but chromosome stickiness and abnormal cytokinesis were observed in low
frequency. All abnormalities can compromise pollen viability by generating unbalanced gametes. Based on the chromosome number
and meiotic stability, the present study indicates the apomictic tetraploid accessions that can act as male genitor to produce
interspecific hybrids with B. ruziziensis or intraspecific hybrids with recently artificially tetraploidized accessions. 相似文献
10.
本文通过建立图象分析方法对免疫组织化学反应结果进行定量,检测观察H-ras在口腔颊粘膜上皮在正常(N)、慢性炎症(IF)、癌旁上皮(EAC)和鳞癌(SCC)的变化过程中的表达并进行分析。结果显示H-ras在SCC组中,以中等分化的SCC无论是H-ras表达的量还是细胞阳性率都较高。此外,组织学观察显示,H-ras在处于分化末期但尚未角化的正常上皮细胞中有较高的表达。本文结果显示了H-ras的过表达与上皮细胞的会化程度密切相关。本研究还显示,所采用的阳性区域透光值、平均总透光值及阳性反应区域与阴性反应区域比值可靠并有相关性。这进一步说明了用免疫组化定量方法检测H-ras癌基因表达的精确和可靠性。 相似文献