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71.
The Goodwin and Trainor model of pattern generation in calcium-regulated strain fields is studied in the case where calcium input and calcium output processes are involved. It is shown that the properties of the original model may still remain provided that the input-output processes are not unstable. In this last case, despite the eventual stabilizing effect of the calcium exchange term, perturbations of the generalized system can grow and lead to inhomogeneous solutions. Applications to cell differentiation and cell growth are discussed. 相似文献
72.
V. Molitor M. Trnka W. Erber I. Steffan M. -E. Rivière B. Arrio H. Springer-Lederer G. A. Peschek 《Archives of microbiology》1990,154(2):112-119
During adaptation of photoautotrophically growing fresh water cyanobacterium Anacystis nidulans to high salinity the cells showed a pronounced increase of proton-sodium antiporter activity, and of cytochrome c oxidase in isolated and purified plasma membrane. At the same time the concentrations of plasma membrane-bound EDTA-resistant copper and iron (determined by inductively coupled plasma atomic emission spectrometry) rose proportionately, accompanied by an increase in whole cell respiration. In plasma membranes from salt adapted cells lipid/protein ratios were markedly higher than in control cells, levels of esterified saturated and long-chain fatty acids being significantly higher than the respective levels of unsaturated and short-chain fatty acids which explains the higher lipid-phase transition temperatures derived from Arrhenius plots. Immunoblotting of the membrane proteins with antisera raised against the cytochrome c oxidases from Paracoccus denitrificans and A. nidulans gave two cross-reacting bands with apparent molecular weights around 50000 and 30000 (subunits I and II, respectively) which were more pronounced in plasma membranes from salt adapted cells when compared to control cells. The protein pattern of plasma membranes from salt adapted cells also showed the appearance of bands at apparent molecular weights of 44000–48000 and 54000–56000 which might stem from the proton/sodium-antiporter in this membrane.Abbreviations CM
cytoplasmic or plasma membrane
- ICM
intracytoplasmic or thylakoid membrane
- cyt
cytochrome
- DCCD
N,N-dicyclohexylcarbodiimide
- Hepes
N-2-hydroxyethylpiperazine-N-2-ethanesulfonate
- ICP-AES
inductively coupled plasma atomic emission spectrometry
- SDS-PAGE
sodium dodecylsulfate polyacrylamide gel electrophoresis
- EPR
electron paramagnetic resonance spectrometry 相似文献
73.
Cystic fibrosis typing with DNA probes and screening for ΔF508 deletion in families from Southern France 总被引:1,自引:1,他引:0
Mireille Claustres Marie Desgeorges Paule Kjellherg Hélène Bellet Jacques Demaille Michelle Ramsay 《Human genetics》1990,85(4):398-399
Summary A sample of 235 individuals from 49 French cystic fibrosis (CF) families with at least one living affected child was typed
with probes for restriction fragment length polymorphisms (RFLPs) known to be linked to the CF gene, and was screened for
the ΔF508 mutation. Using a combination of six probes, 44 out of the 49 families were sufficiently informative to enable prenatal
diagnosis or carrier determination. As in many other populations, linkage disequilibrium was found between the CF locus and
the haplotype B (XV2c: allele 1; KM19: allele 2), which accounts for about 78% of CF chromosomes in our families. The ΔF508
deletion was present in 64.3% of CF chromosomes. 相似文献
74.
Marie-Hélène Chaput Darasinh Sihachakr Georges Ducreux Dominique Marie Nasrine Barghi 《Plant cell reports》1990,9(8):411-414
In order to regenerate somatic hybrids, mesophyll protoplasts from a dihaploid potato, BF15 (H1), were electrofused with those from two other dihaploid clones, Aminca (H6) and Cardinal (H3). Determination of the ploidy level by flow cytometry showed that 10% of plants regenerated from the fusion experiment with BF15 + Aminca were diploids, 14% triploids, 63% tetraploids and very few were mixoploids or had a higher ploidy level. Using morphological markers and vigour in plant growth, we were able to recover a total of 24 somatic hybrid plants, respectively 20 and 4 hybrids (accounting for 12% and 13% of regenerants) from the fusions BF15 + Aminca and BF15 + Cardinal. Most of the somatic hybrids were at the expected tetraploid level (2n=4x=48). The hybrid nature was confirmed by examining isoenzyme patterns for malate dehydrogenase (MDH) and isocitrate dehydrogenase (ICD). 相似文献
75.
Twelve loci have been assigned to rat chromosome 5: aldolase B (ALDOB), atrial natriuretic factor (ANF = pronatriodilatin, PND), D4RP1, DSI1, galactosyltransferase (GGTB2), glucose transporter (GLUT1), interferon alpha 1 and related interferon alpha (INFA), interferon beta (INFB), lymphocyte-specific protein-tyrosine kinase (LCK), oncogene MOS, alpha 2U-globulin (major urinary protein, MUP), and orosomucoid (ORM, also called alpha 1-acid glycoprotein, AGP). Among these, the interferon alpha and beta genes map in the q22-23 region, which also contains a transformation suppressor gene (SAI1). The other loci reside outside this region. This study also indicated that the rat genome contains 2 LCK genes, unlike the human and murine genomes. These new assignments on rat chromosome 5 demonstrate that this chromosome is highly homologous to mouse chromosome 4 and carries synteny groups conserved on human chromosome 9 (interferon alpha and beta, galactosyltransferase, orosomucoid, and aldolase B genes) and on the short arm of human chromosome 1 (MYCL, glucose transporter, protein kinase LCK, and atrial natriuretic factor genes). 相似文献
76.
A simple procedure is described for the determination of the photosensitizing potency of drugs, using three leukemic cell lines, two of lymphocytic origin, L1210 and P388 and one of erythroid type, Friend-745. The procedure allows one to investigate several aspects of the photosensitization properties of tested compounds such as cellular localization and direct (trypan blue exclusion) or delayed (clonogenicity) photomediated toxicities.The method was assessed using crude hematoporphyrin derivative (HPD) as well as dihematoporphyrin ether (DHE) or commercially available Photofrin II. Results were compared to those obtained with normal cells, e.g spleen lymphocytes and erythropoietic stem cells (CFU-e), and discussed in the light of the relative response of normal versus transformed cells.Abbreviations DHE
Dihematoporphyrin Ether
- FCS
Fetal Calf Serum
- HPD
Hematoporphyrin Derivative
- PDT
Photodynamic Therapy 相似文献
77.
Kunio Yonemasu Takako Sasaki Yoshiko Dohi Charles M. Lapière Betty Nusgens 《生物化学与生物物理学报:疾病的分子基础》1990,1096(1):47-51
C1q, a collagen-like complement protein, was purified from the serum of a ddermatosparactic calf which lacks procollagen N-terminal proteinase (pN-proteinase). The specific hemolytic activity of the serum Clq from the dermatosparactic animal was identical to that of C1q from a normal calf. Gel-filtration of serum from dermatosparactic calf, on Sepharose 6B, showed the presence of C1q-antigenic material at only one position which was identical to the elution position of normal bovine C1q. No differdence, under dissociating conditions, could be seen in the size of the chains of C1q in specific immunoprecipitates isolated from the sera of dermatosparactic and normal animals, as judged by polyacrylamidegel electrophoresis (PAGE) in the presence of sodium dodecyl sulfate (SDS). The C1q from the dermatosparactic animal showed the same N-terminal amino acid and typtic-digest peptide pattern on HPLC as C1q from the normal calf. These results strongly suggest that pN-proteinase is not involved in the extracellular processing of C1q. 相似文献
78.
M Chauvière A Martinage P Sautière P Chevaillier 《Reproduction, nutrition, development》1990,30(3):349-354
During dog-fish spermiogenesis, 2 basic nuclear protein transitions occur: the first from histones to spermatid-specific proteins S1 and S2, the second leading to protamines. S1, the most abundant transition protein, is a polypeptide containing 87 residues (Mr = 11,179 Da) whereas S2, the minor transition protein, contains 80 residues (Mr = 9,726 Da). The 2 proteins are mainly characterized by an asymmetry of the molecule, a very high content of basic residues, a relatively high level of hydrophobic residues and a cluster of acidic residues in the carboxy-terminal quarter of the molecule. The 2 proteins are phosphorylated on serine residues and the degree of phosphorylation is relatively important in protein S1. The 2 transition proteins are structurally unrelated to testis histones or sperm protamines and cannot be considered either as their proteolytic degradation products or as their precursors. 相似文献
79.
Effect of positive redox potentials (>+400mV) on the expression of anaerobic respiratory enzymes in Escherichia coli 总被引:4,自引:2,他引:2
The expression of fumarate reductase and other enzymes of anaerobic respiration in Escherichia coli was studied as a function of the redox potential (Eh) in the medium. Redox potentials up to +300 mV allowed full expression of fumarate reductase (frd) genes. Higher values resulted in decreased expression. The relationship between Eh and expression of frd could be approximated by the Nernst equation, assuming a redox couple with a midpoint potential Eo' = +400 mV to 440 mV. At Eh values greater than +510 mV (generated anaerobically by hexacyanoferrate(III] the degree of repression was the same as that obtained by O2. Hexacyanoferrate(III) also caused decreased activities of dimethylsulphoxide (DMSO), nitrite and nitrate reductases. Since expression of these enzymes depends on FNR, the gene activator of anaerobic respiratory genes, it is suggested that the function of FNR is controlled by a redox couple of Eo' = +400 mV to 440 mV. 相似文献
80.
A novel oncogene related to c-mil is transduced in chicken neuroretina cells induced to proliferate by infection with an avian lymphomatosis virus. 总被引:7,自引:0,他引:7 下载免费PDF全文
M Marx A Eychne D Laugier C Bchade P Crisanti P Dezle B Pessac G Calothy 《The EMBO journal》1988,7(11):3369-3373
Non-dividing neuroretina cells from chicken embryos are induced to proliferate after a long latency, following infection with Rous associated virus type 1, an avian retrovirus which does not carry a transforming gene. We have isolated from these proliferating cells an acutely mitogenic retrovirus, designated IC10, which contains a novel oncogene. Nucleotide sequencing showed that the IC10 virus has transduced 1101 nucleotides of cellular origin inserted between the gag and env genes of RAV-1. This oncogene, designated v-Rmil, is 70.1% homologous to v-mil. v-Rmil encodes a protein of 40,976 daltons sharing 83.8% homology with the catalytic domain of the v-mil protein. Divergence with the v-mil gene product is observed at the NH2- and COOH-terminal portions of the v-Rmil protein. Restriction analysis of normal chicken DNA indicated that v-Rmil is derived from a cellular gene distinct from c-mil. The c-Rmil gene is transcribed through a major mRNA, greater than 10 kb in length, that is detected at much higher levels in neuroretinas, as compared to other embryonic tissues. 相似文献