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101.
Clerosterol-[26-14C], a 24β-ethyl-25-methylene sterol [(24S)-24-ethylcholesta-5,25-dien-3β-ol], was incorporated into clionasterol and poriferasterol by cultures of the green algae Trebouxia sp. 213/3 and Trebouxia sp. 219/2. Degradation of the labelled poriferasterol showed that the 14C retained its identity and was not incorporated as a result of metabolism of the clerosterol-[26-14C] and randomisation of label. These results are consistent with the proposed production, and subsequent reduction, of a 24β-ethyl-25-methylene intermediate in 24β-ethyl sterol biosynthesis in algae of the order Chlorococcales. 相似文献
102.
Catherine Richard Claude Delaude Louisette Le Men-Olivier Jean Le Men 《Phytochemistry》1978,17(3):539-541
The structure of a new bisindole alkaloid has been elucidated by chemical correlation and analysis of 13C NMR spectra. 相似文献
103.
Lieve de Clercq Claude Remacle Jean Demal 《In vitro cellular & developmental biology. Plant》1977,13(2):85-90
Summary The use of a semi-natural medium (Eagle’s MEM supplemented with chicken embryo extract) appears to be satisfactory for ovarian
and testicular fragment cultures ofCarassius auratus. The male germ cells show a normal degeneration which might be attributed to a lack of pituitary hormones: gonadotropic and,
possibly, somatotropic hormone. The ovarian fragments maintain a normal organization during 21 days of culture. Only the occytes
in late vitellogenesis massively atresiate at the beginning of culture. The addition of fetal bovine serum to this medium
produces surprising effects on the testicular explants, particularly on the spermatogonial mitoses. This might be attributed
to the presence of STH and androgen in the serum. The modifications of ovarian explants, on the other hand, are identical
to those observed with Eagle’s MEM supplemented with chicken embryo extract. M 199 has been tested as a synthetic medium;
the preliminary results are encouraging. Testosterone, when added to the semi-natural medium, permits complete spermatogenesis
in the testicular fragments during the 21 days of culture, but does not produce any effect on the ovarian explants. 相似文献
104.
Claudine Grégori Claude Besmond Axel Kahn Jean-Claude Dreyfus 《Biochemical and biophysical research communications》1982,104(2):369-375
High molecular weight cellular RNA was isolated from adult and fetal human liver tissue by a procedure of ethanol precipitation in concentrated guanidine-HCl solutions. About 5 mg of RNA were obtained from one gram of liver. RNA was fractionated by sucrose gradient ultracentrifugation. Aldolase B neosynthesized in a reticulocyte lysate cell-free system under the direction of total or fractionated RNA was purified by immunoaffinity microchromatography. Messenger RNA specifying synthesis of aldolase B exhibited a sedimentation coefficient of 16 S both in adult and fetal liver. This enzyme represented 1.3 % of the total neosynthesized proteins in adult liver, 0.1 % in the liver of a 6-month-old fetus and less than 0.01 % in the liver of a 4.5 month-old fetus. 相似文献
105.
Heinz Egge Jean Claude Michalski Gerard Strecker 《Archives of biochemistry and biophysics》1982,213(1):318-326
Three oligosaccharides isolated from the urine of a patient suffering from mannosidosis, a Man9GlcNAc, a Man8GlcNAc, and a Man7GlcNAc, were analyzed by electron impact mass spectrometry at 20 eV after reduction with NaB2H4 and permethylation. Molecular ions were observed at 2144, 1940, and 1736, respectively. In the high-mass range very intense ions were found at M-45. The mass spectrum of the homogenous decasaccharide Man9GlcNAc1D contains ions that could be attributed to specific parts of each of the three antennae of the molecule. Thus characteristic key ions were recognized. With the aid of these key ions the spectra of the nona- and octasaccharide mixtures could be evaluated in a qualitative and a semiquantitative way. In the nonasaccharide all three possible isomers that can be produced by cleavage of one of the three terminal α-mannoses are present, although in differing amounts. However, only five of the six possible isomers of the octasaccharide could be detected. 相似文献
106.
Murine H-2Dd-reactive monoclonal antibodies recognize shared antigenic determinant(s) on human HLA-B7 or HLA-B27 molecules or both 总被引:4,自引:0,他引:4
Najet Rebai Pierre Mercier Tom Kristensen Christian Devaux Bernard Malissen Claude Mawas Michel Pierres 《Immunogenetics》1983,17(4):357-370
We have evaluated the serological relationships between the murine H-2Dd and human HLA molecules using four H-2Dd-reactive monoclonal antibodies (mAbs) produced in the A.BY (KbIbDb) anti-A.TL (KsIkDd) combination. In the mouse, these reagents exhibited three distinct reactivity patterns: Dd, Ks, and H-2u (mAb 81.L); Dd, H-2p, and H-2u (mAb 81.R); and Dd, Kd, H-2p, H-2u, and H-2v (mAbs 97.G and 97.H). Sequential immunoprecipitation and cross-competitive mAb binding experiments revealed that these mAbs recognized determinants in two spatially distinct polymorphic domains on the H-2Dd molecule of B10.A(5R) cells (defined by mAbs 81.L and 81.R, 97.H, and 97.G, respectively). MAbs 81.R, 97.G, and 97.H, but not 81.L, also defined an HLA-linked polymorphism in the human, the main characteristics of which can be summarized as follows: (i) on B lymphoblastoid cell lines, mAbs 81.R and 97.H bound to cells expressing the HLA-B7, HL-B27 or Bw40 cross-reacting specificities, (ii) on peripheral blood lymphocyte (PBL) panel mAb 81.R exerted C dependent cytotoxicity to 118 of 400 cells tested, including almost all HLA-B7 or HLA-B27 cells or both (r: 0.952), (iii) the expression of the 81.R cross-reacting determinant segregated in an informative family with the parental haplotype carrying the HLA-B7 allele, and (iv) mAbs 81.R, 97.G, and 97.H recognized topologically related determinants on the same class I molecule(s) of the human B lymphoblastoid cells JY (HLA-A2,2, -B7,7). These data support the view that some, but not all H-2Dd allotopes have been conserved throughout evolution and are associated in the human with the HLA-B7, -B27 cross-reacting specificities. 相似文献
107.
The gap between the theoretical biological potential of microalgae and the biomass productivity obtained with algal culture in tubular biophotoreactors is due to a reduced growth rate related to hydrodynamic stress of pumping. High levels of mixing are necessary to reach a turbulent flow of the culture, in order to optimize the light regime. The optimal conditions of pumping to produce this significant liquid mixing may produce some cell damage. Factors affecting this hydrodynamic stress (geometry of the bioreactor involved, type of pump utilized, morphology of algal cells, physiological conditions of microalgae, etc.) are discussed. 相似文献
108.
Jean-Pierre Alazard Corine Millet-Paillusson O. Boy Daniel Gu nard Ang le Chiaroni Claude Riche Claude Thal 《Bioorganic & medicinal chemistry letters》1991,1(12):725-728
The tricyclic lactams 3 and 4 having a phenylpyrrole framework have been prepared from the arylpyrroles 5 and 16 respectively. These structural analogs of rhazinilam 1 present, like the latter, an interesting antitubulin and cytotoxic activity. 相似文献
109.
Pierre Valeix Paul Preziosi Claude Rossignol Marie-Alice Farnier Serge Hercberg 《Biological trace element research》1992,32(1-3):259-266
Urinary iodine excretion was assessed in 642 healthy children aged 10 mo (n=243), 2 yr (n=183), and 4 yr (n=216) living in the Paris area and originating from continental France (60.3%), North Africa (13.8%), the West Indies (9.1%),
West Africa (8.3%), Southeast Asia (4.8%), and southern Europe (3.8%). Mild impairment of neurological (reflexes, tone, audiometry)
and intellectual development (Brunet-Lézine scale) was assessed in relation to iodine status. Iodine excretions (median values)
were 18.4, 11.9, and 10.9 μg/100 mL at 10 mo, 2 yr, and 4 yr, respectively, and risk of mild iodine deficiency (5–10 μg/100
mL) was 18.1%, 34.8%, and 38.3% for the same age groups. No relationship was found between anthropometry, global development
quotient, and iodine status. High hearing thresholds were more commonly associated with lower iodine excretion, suggesting
mild hearing defects. In spite of iodine prophylaxis, the risk of mild to moderate iodine deficiency still exists in France
and in a number of European countries. Evaluation of neurological sequels of borderline iodine status is a major public health
problem in European communities. 相似文献
110.
Transient expression of foreign genes introduced on a plasmid into isolated plant protoplasts is widely used to study the control of gene expression. Unfortunately, many experimental variables implicated in this technique are difficult or impossible to control, resulting in a disturbing degree of variability between otherwise identical experiments. We have studied the co-expression of two constitutively expressed genes located on the same plasmid. This has allowed us to identify the lot of plasmid DNA as an important source of variation, along with the protoplast lot. Plasmid DNA concentration was found to be of minor importance. Since the variation of expression level of the two genes was identical for the two genes in all experiments, we propose the use of an internal standard in all comparative transient expression studies, which allows the reduction of the variation between experiments by one order of magnitude.Abbreviations CaMV
cauliflower mosaic virus
- CAT
chloramphenicol acetyl transferase
- GUS
ß-glucuronidase synthase
- MS
medium after Murashige and Skoog (1962)
- MU
methyl umbelliferone
- NOS
nopaline synthase
- NPT
II-neomycin phospho transferase
- PEG
polyethylene glycol
- Tris
tris-hydroxymethyl aminoethane 相似文献