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41.
Clinical and biochemical studies in three patients with severe early infantile Cockayne syndrome 总被引:2,自引:0,他引:2
Jaak Jacken Helmut Klocker Helga Schwaiger Romuald Bellmann Monica Hirsch-Kauffmann Manfred Schweiger 《Human genetics》1989,83(4):339-346
Summary We present clinical and biochemical data from three patients with severe Cockayne syndrome (CS) of very early onset. Unlike in classic CS, signs became evident in the first weeks of life and led to unusually early death. Fibroblasts from two of the patients showed a complete defect of the repair of UV-induced thymine dimer lesions. They were unable to remove thymine dimer lesions from their DNA, had a severe reduction of the RNA synthesis rates after UV irradiation, and showed no reactivation of an UV-inactivated indicator gene and no DNA recondensation after UV irradiation. DNA repair investigated in these two fibroblast cell strains resembled that of xeroderma pigmentosum cells of complementation group A. In contrast, fibroblasts from the third patient showed the same in vitro repair characteristics as classic CS cells. 相似文献
42.
Helmut Wieczorek Gabriele Wolff 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1989,164(6):825-834
1. | The electrophysiology of the sugar receptor in labellar taste hairs ofDrosophila melanogaster (Diptera) was investigated using 33 monosaccharides, oligosaccharides, glucosides, and amino acids which in calyptrate flies are known to bind to specific receptor sites or which may be assigned to specific receptor sites on the basis of structural criteria. |
2. | The pyranose site ofDrosophila is very similar to the pyranose site of the calyptrate flies: regarding monosaccharides of the pyranose type three adjacent equatorial hydroxyl groups (C-2, C-3, C-4) seem to be important for stimulating effectiveness. On the other hand, it exhibits a more rigid stereospecificity with regard to the substituents at C-1 and C-5. |
3. | A furanose site as in calyptrate flies does not exist inDrosophila. First, D-galactose, phenylalanine and 2,5-anhydro-D-mannitol are not or nearly not stimulatory. Secondly, according to different sugar receptor responses after treatment of the taste hairs with papain, D-fucose binds to another receptor site than D-fructose. Thirdly, the effective conformation of D-fructose is not the furanose, but most probably the pyranose form as can be concluded from experiments with freshly prepared and equilibrium solutions of D-fructose. |
4. | The characteristic differences between the properties of the sugar receptors ofDrosophila and of the calyptrate flies lead to the suggestion that the actual number of types of receptor sites in the various fly species is greater than assumed up till now. The broad specificity of the sugar receptors of flies may therefore result from a mosaic of different types of highly specific receptor sites. |
43.
M Mendler S G Eich-Bender L Vaughan K H Winterhalter P Bruckner 《The Journal of cell biology》1989,108(1):191-197
The distribution of collagen XI in fibril fragments from 17-d chick embryo sternal cartilage was determined by immunoelectron microscopy using specific polyclonal antibodies. The protein was distributed throughout the fibril fragments but was antigenically masked due to the tight packing of collagen molecules and could be identified only at sites where the fibril structure was partially disrupted. Collagens II and IX were also distributed uniformly along fibrils but, in contrast to collagen XI, were accessible to the antibodies in intact fibrils. Therefore, cartilage fibrils are heterotypically assembled from collagens II, IX, and XI. This implies that collagen XI is an integral component of the cartilage fibrillar network and homogeneously distributed throughout the tissue. This was confirmed by immunofluorescence. 相似文献
44.
P Bruckner I H?rler M Mendler Y Houze K H Winterhalter S G Eich-Bender M A Spycher 《The Journal of cell biology》1989,109(5):2537-2545
Primary chondrocytes from whole chick embryo sterna can be maintained in suspension culture stabilized with agarose for extended periods of time. In the absence of FBS, the cells remain viable only when seeded at high densities. They do not proliferate at a high rate but they deposit extracellular matrix with fibrils resembling those of authentic embryonic cartilage in their appearance and collagen composition. The cells exhibit many morphological and biochemical characteristics of resting chondrocytes and they do not produce collagen X, a marker for hypertrophic cartilage undergoing endochondral ossification. At low density, cells survive in culture without FBS when the media are conditioned by chondrocytes grown at high density. Thus, resting cartilage cells in agarose cultures can produce factors required for their own viability. Addition of FBS to the culture media leads to profound changes in the phenotype of chondrocytes seeded at low density. Cells form colonies at a high rate and assume properties of hypertrophic cells, including the synthesis of collagen X. They extensively deposit extracellular matrix resembling more closely that of adult rather than embryonic cartilage. 相似文献
45.
46.
Development of PCR markers linked to resistance to wheat streak mosaic virus in wheat 总被引:8,自引:0,他引:8
L. E. Talbert P. L. Bruckner L. Y. Smith R. Sears T. J. Martin 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,93(3):463-467
Wheat streak mosaic virus (WSMV), vectored by the wheat curl mite (Acer tulipae), is an important disease of wheat (Triticum aestivum L.) in the North American Great Plains. Resistant varieties have not been developed for two primary reasons. First, useful sources of resistance have not been available, and second, field screening for virus resistance is laborious and beyond the scope of most breeding programs. The first problem may have been overcome by the development of resistance to both the mite and the virus by the introgression of resistance genes from wild relatives of wheat. To help address the second problem, we have developed polymerase chain reaction (PCR) markers linked to the WSMV resistance gene Wsm1. Wsm1 is contained on a translocated segment from Agropyron intermedium. One sequence-tagged-site (STS) primer set (WG232) and one RAPD marker were found to be linked to the translocation containing Wsm1. The diagnostic RAPD band was cloned and sequenced to allow the design of specific PCR primers. The PCR primers should be useful for transferring Wsm1 into locally adapted cultivars.This is Journal Series No. J-4041 of the Montana Agricultural Experiment Station 相似文献
47.
The allylidene complex (CO)5W=CH---C(Ph)=C(Ph)H (4) reacts with cyclopentadiene by stereospecific transfer of the carbene ligand to one of the two double bonds of cyclopentadiene to give a cis-divinylcyclopropane complex 5. The divinylcyclopropane ligand coordinates to the metal via the unsubstituted double bond. Addition of bromide to solutions of 5 gives rise to the formation of [(CO)5WBr]− and a bicyclo[3.2.1]octadiene (6), the Cope rearrangement product of the free divinylcyclopropane. Thermolysis of 5 affords 6 and its (CO)5W complex. The reaction of 4 with furan (8a), 2-methylfuran (8b) and 3-methylfuran (8c) affords the (CO)5W(bicyclo[3.2.1]oxahepta- diene) complexes (9a–c), The formation of 9a–c which is chemo-, regio- and stereospecific is explained by a tandem cyclopropanation/Cope rearrangement sequence. The bicyclic ligands 10a–c are liberated from the metal either by thermolysis of solutions of 9a–c or by addition of bromide. 相似文献
48.
Stefan Boehm Sigismund Huck Gabriele Koth Helmut Drobny Ernst Agneter Ernst A. Singer 《Journal of neurochemistry》1994,63(1):146-154
Abstract: This study explores the role of cyclic AMP in electrically evoked [3H]noradrenaline release and in the α2-adrenergic modulation of this release in chick sympathetic neurons. Along with an increase in stimulation-evoked tritium overflow, applications of forskolin enhanced the formation of intracellular cyclic AMP. Both effects of forskolin were potentiated by the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine. The forskolin-induced increase in overflow was abolished by the Rp-diastereomer of cyclic AMP-thioate, an antagonist at cyclic AMP-dependent protein kinases, and 1,9-dideoxy-forskolin, an inactive analogue at adenylyl cyclase, had no effect on the evoked overflow. A 24-h pretreatment with either cholera toxin or forskolin reduced the subsequent forskolin-induced accumulation of cyclic AMP and inhibited the stimulation-evoked release. Basal cyclic AMP production, however, remained unaltered after forskolin treatment and was enhanced after 24 h of cholera toxin exposure. The α2-adrenergic agonist bromoxidine did not affect the formation of cyclic AMP stimulated by forskolin but reduced electrically evoked release. However, effects of bromoxidine on 3H overflow were attenuated by forskolin as well as by 8-bromo-cyclic AMP. Effects of bromoxidine on [3H]noradrenaline release were paralleled by an inhibition of voltage-activated Ca2+ currents, primarily through a delayed time course of current activation. This effect was abolished when either forskolin or 8-bromo-cyclic AMP was included in the pipette solution. Both substances, however, failed to affect Ca2+ currents in the absence of bromoxidine. These results suggest that the signaling cascade of the α2-adrenergic inhibition of noradrenaline release involves voltage-activated Ca2+ channels but not cyclic AMP. Elevated levels of cyclic AMP, however, antagonize this α2-adrenergic reduction, apparently through a disinhibition of Ca2+ channels. 相似文献
49.
Structural organization and differential expression of three stilbene synthase genes located on a 13 kb grapevine DNA fragment 总被引:10,自引:0,他引:10
Wilfried Wiese Barbara Vornam Elvira Krause Helmut Kindl 《Plant molecular biology》1994,26(2):667-677
A 13 kb DNA fragment was isolated from a grapevine (Vitis var. Optima) genomic library by hybridizing with elicitor-induced stilbene synthase cDNA as a probe. After fragmentation with Eco RI, subcloning and sequencing, two full-size stilbene synthase genes (Vst1 and Vst2) and the 3 end of a third stilbene synthase gene (Vst3) were located within the 13 kb fragment. Vst1 and Vst2, differing only slightly in the coding region, are distinguished in the intron size and in the structure of the promoter region. The 5 flanking region of gene Vst1 contains a TATAA box at nucleotide –48. The substantial structural differences found for the promoters of the two genes are paralleled by a striking difference in the expression of the two genes in elicitor-treated cells. Moreover, the accumulation upon elicitation of six different stilbene synthase mRNAs was studied and found to differ by two orders of magnitude. 相似文献
50.
Nucleotide sequence information from a partial genomic clone, a cDNA clone, a RACE clone and a PCR fragment was combined to reconstruct the first reported complete gene sequence encoding a large legumin subunit, designated LelB3. The length difference to the well-characterized major legumin subunits is caused by an extended glutamin/glutamic acid-rich region encoded by the C-terminal part of the chain. Amino acid sequence comparisons reveal that gene LelB3 is more closely related to B-type than to A-type legumin genes of Vicia faba. Gene LelB3 is a member of a small gene family as indicated by published (Pich and Schubert, Biol Zbl 112 (1993); 342–350) and limited own data. 相似文献