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71.
Phorbol ester increases the level of interleukin 2 mRNA in mitogen-stimulated human lymphocytes 总被引:8,自引:0,他引:8
T Hirano K Fujimoto T Teranishi N Nishino K Onoue S Maeda K Shimada 《Journal of immunology (Baltimore, Md. : 1950)》1984,132(5):2165-2167
TPA alone did not induce the production of IL 2 in human tonsillar lymphocytes but enhanced the PHA-induced IL 2 production by seven-fold. That the effect of TPA was due to an increase in IL 2 mRNA was demonstrated by examining the amount of IL 2 mRNA translatable in Xenopus laevis oocytes, and by Northern blotting analysis using IL 2 cDNA as a probe. In these ways, it was shown that TPA alone did not induce any significant IL 2 mRNA synthesis, but when added together with PHA it increased the level of IL 2 mRNA by at least 10-fold, as compared with that induced by PHA alone. 相似文献
72.
Abstract. Intrarectal administration of sodium deoxycholate (SDC) enhances experimental colorectal carcinogenesis, an effect that is partly vitiated by oral metronidazole. the effect of topical SDC with or without concurrent metronidazole on colorectal cell proliferation was explored in male Sprague-Dawley rats ( n = 30) allocated to five groups. Two groups received thrice weekly intrarectal instillations of 1 ml N saline or 1 ml 0.12 m SDC. A third group received SDC plus metronidazole 22.5 mg/kg/day in the drinking water. Controls had no instillations or metronidazole alone. At time of killing (10 weeks), crypt cell production rate (CCPR) was determined by the stathmokinetic technique for four large-bowel segments. Saline had no significant effect on colorectal CCPR but SDC produced increases throughout, varying from 53% in the proximal colon to 222% in the rectum ( P < 0.01). Metronidazole did not reduce this effect, although given alone it reduced colonic CCPR by 40 to 50%. the direct tropic effect of bile acids could largely explain their cocarcinogenic properties. Since metronidazole does not prevent this increase in cell proliferation, its mildly protective role against cancer may reflect the presence of fewer anaerobes capable of degrading bile acids to carcinogenic metabolites. 相似文献
73.
Isolation and characterization of a human interleukin 2 gene 总被引:1,自引:0,他引:1
S Mita S Maeda K Obaru N Nishino K Shimada T Hirano K Onoue T Ogawa H Ogawa 《Biochemical and biophysical research communications》1983,117(1):114-121
An interleukin 2 (IL-2) gene was isolated from a Charon 4A human gene library. Electron microscopic examination of 15 heteroduplexes formed between the genomic DNAs and the IL-2 cDNAs demonstrated that the size of the IL-2 gene is about 5.1 +/- 0.5 kb and that there are at least two introns in this gene. Nucleotide sequence of the 5' flanking region of the IL-2 gene showed a homology with that of the corresponding region of the human immune interferon gene. 相似文献
74.
Isolation and characterization of nucleases from a clinical isolate of Serratia marcescens kums 3958 总被引:1,自引:0,他引:1
Two new extracellular nucleases, nucleases SM1 and SM2, were purified from the culture fluid of S. marcescens kums 3958, a fresh clinical isolate. The purification was carried out by the following steps; ammonium sulfate precipitation, and DEAE-cellulose and Sephadex G-100 column chromatography. At the final step, nucleases SM1 and SM2 were purified about 3,700- and 1,000-fold, respectively. They were free from phosphomonoesterase and phosphodiesterase activities. The pIs were 8.1 and 7.5 for nucleases SM1 and SM2, respectively. The molecular weight was estimated to be 35,000 for both enzymes by SDS-polyacrylamide disc gel electrophoresis. The results of amino acid analyses showed that both the threonine and serine contents were higher in nuclease SM2 than in SM1. Furthermore, nuclease SM1 was more stable than nuclease SM2 at 4 degrees C. The other properties of the two enzymes were similar; pH optimum (8.0), Mg2+ or Mn2+ for activation, and inhibition by chemical reagents such as EDTA and pyrophosphate. No significant difference was found in base specificity between nucleases SM1 and SM2. Both enzymes specifically degraded double-stranded homopolymers, especially poly(I). poly(C), as well as yeast RNA and calf thymus DNA. They hardly degraded, however, single-stranded homopolymers such as poly(dA), poly(G), and poly(U). 相似文献
75.
Isolation and characterization of a third proteoglycan (PG-Lt) from chick embryo cartilage which contains disulfide-bonded collagenous polypeptide 总被引:11,自引:0,他引:11
A Noro K Kimata Y Oike T Shinomura N Maeda S Yano N Takahashi S Suzuki 《The Journal of biological chemistry》1983,258(15):9323-9331
Chick embryo epiphyseal cartilage has been shown to contain three different proteoglycan species (PG-H, PG-Lb, and PG-Lt). This report is concerned with the purification and characterization of the third proteoglycan, PG-Lt. The proteoglycan can be separated from the other two by virtue of its low buoyant density in a CsCl density gradient and further purified by consecutive ion exchange and gel chromatography. The final preparation is composed of PG-Lt monomer and PG-Lt oligomer. The amino acid composition of PG-Lt is quite different from that of PG-H and PG-Lb and rather resembles that of collagens with respect to high content of glycine and high degrees of hydroxylation of proline and lysine. PG-Lt monomer is composed of disulfide-bonded subunits of Mr congruent to 120,000 and 190,000 as demonstrated by its gel electrophoretic behavior after reduction with 2-mercaptoethanol. The latter, but not the former, contains dermatan sulfate chains with glucuronic acid/iduronic acid residues and yields a protein-enriched core molecule of Mr congruent to 100,000 after digestion with chondroitinase ABC. Both of the protein subunits are completely digestible with bacterial collagenase. Immunofluorescence microscopic examination of cartilage tissues, using an antibody against PG-Lt, shows that this proteoglycan exists in both the cartilage matrix and perichondrial noncartilagenous region. When chondrocytes are plated onto tissue culture dishes, the antibody stains strands found on the cell surfaces and in the intercellular space of substrate-attached cell layers, suggesting that PG-Lt mediates cell-to-cell and cell-to-substrate contacts. 相似文献
76.
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79.
Sandro Cavicchi Daniela Guerra Vanna Natali Cristina Pezzoli Gianfranco Giorgi 《Journal of evolutionary biology》1989,2(4):235-251
From a laboratory stock of Drosophila melanogaster (Oregon), reared for more than 20 years at 18° C, a new population was derived and maintained at 28° C for 8 years. The chromosomal and cytoplasmic contribution to genetic divergence between the two populations was estimated. Six body traits and reproductive fitness were taken into account. The third chromosome is responsible for the adaptive difference for temperature between the two lines. Temperature-selected genes which control body size are located on the second and third chromosomes, although the contribution of each chromosome depends on the environment in which the flies develop. The correlation between the chromosomal and cytoplasmic contributions to different traits and fitness, changes with temperature. At 28° C the correlation between fitness and each body trait is proportional to the response to selection exhibited by each of them, but this is not true at 18° C. Body size has, therefore, an adaptive significance in relation to temperature, which is expressed only in the environment where selection occurs. Cytoplasmic genes affect almost all characters to an extent similar to that of chromosomal genes. Inter-chromosomal and nucleo-cytoplasmic interactions are present and also change with temperature. In general, genes selected in a given environment produce greater phenotypic changes in that environment than in another. The population that experienced both temperatures is fitter in both environments, suggesting that the capacity to adapt to warm temperatures depends on genes other than those which are involved in the adaptation to cold. 相似文献
80.
A highly sensitive chemiluminescent assay for NAD(P)H have been developed. The principle of the method is as follows; NAD(P)H reduces molecular oxygen to superoxide anion (O) and hydrogen peroxide (H2O2) in the presence of 1-methoxy-5-methylphenazinium methyl sulphate (1-MPMS) as electron mediator. The produced O and H2O2 can be measured by chemiluminescent reaction using isoluminol (IL) and microperoxidase (m-POD). A linear relationship between chemiluminescence intensity and NAD(P)H concentration (log/log) was obtained ranged from 10?9 mol/I to 10?5 mol/I. This chemiluminescent reaction has been coupled to the assay of glucose-6-phosphate dehydrogenase (G6PDH), β-D -galactosidase (β-Gal) and alkaline phosphatase (ALP). The detection limits of G6PDH, β-Gal and ALP were 10?18 mol, 10?20 mol and 10?18 mol per assay, respectively. The chemiluminescent assay of these enzymes applied to chemiluminescent enzyme immunoassay for 17α-hydroxy-progesterone and DNA hybridization assay using these enzymes as label. 相似文献