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21.
Jonathan D. G. Jones David A. Jones Gerard J. Bishop Kate Harrison Bernard J. Carroll Steven R. Scofield 《Transgenic research》1993,2(2):63-78
Cell-autonomous genes have been used to monitor the excision of both endogenous transposons in maize andAntirrhinum, and transposons introduced into transgenic plants. In tobacco andArabidopsis, the streptomycin phosphotransferase (SPT) gene reveals somatic excision of the maize transposonActivator (Ac) as green sectors on a white background in cotyledons of seedlings germinated in the presence of streptomycin. Cotyledons of tomato seedlings germinated on streptomycin-containing medium do not bleach, suggesting that a different assay for transposon excision in tomato is desirable. We have tested the use of the spectinomycin resistance (SPEC) gene (aadA) and a Basta resistance (BAR) gene (phosphinothricin acetyltransferase, or PAT) for monitoring somatic excision ofAc in tobacco and tomato. Both genetic and molecular studies demonstrate that genotypically variegated individuals that carry clones of cells from whichAc orDs have excised from either SPEC or BAR genes, can be phenotypically completely resistant to the corresponding antibiotic. This demonstrates that these genes act non-cell-autonomously, in contrast to the SPT gene in tobacco. Possible reasons for this difference are discussed. 相似文献
22.
Anthony G. Lee Kate A. Dalton Richard C. Duggleby J. Malcolm East Anthony P. Starling 《Bioscience reports》1995,15(5):289-298
Effects of lipid structure on the function of the Ca2+-ATPase of skeletal muscle of sarcoplasmic reticulum are reviewed. Binding of phospholipids to the ATPase shows little specificity. Phosphatidylcholines with short (C14) or long (C24) fatty acyl chains have marked effects on the activity of the ATPase, including a change in the stoichiometry of Ca binding. Low ATPase activity in gel phase lipid follows from low rate of phosphorylation. Phosphatidylinositol 4-phosphate increases ATPase activity by increasing the rate of dephosphorylation of the phosphorylated ATPase. Stimulation is not seen with other anionic phospholipids; phosphatidic acid decreases ATPase activity in a Mg2+-dependent manner.Abbreviations di(C141)PC
dimyristoleoylphosphatidycholine
- di(C160)PC
dipalmitoylphosphatidylcholine
- di(C181)PC
dioleoylphosphatidylcholine
- di(Br2C180)PC
dibromostearoylphosphatidylcholine
- di(C241)PC
dinervonylphosphatidylcholine
- di(C181)PA
dioleoylphosphatidic acid
- di(C181)PE
dioleoylphosphatidylethanolamine
- Ptdlns
phosphatidylinositol
- PtdIns-4P
phos-phatidylinositol 4-phosphate 相似文献
23.
Human medulloblastoma gangliosides 总被引:2,自引:0,他引:2
To establish a model system for the study of ganglioside metabolismof the human brain tumor, medulloblastoma, we have chemicallycharacterized the gangliosides of the Daoy cell line. Thesecells contain a high concentration of gangliosides (143 ±13 nmol LBSA/108 cells). The major species have been structurallyconfirmed to be GM2 (65.9%), GM3 (13.0%), and GDla (10.3%).Isolation of individual gangliosides homogeneous in both carbohydrateand ceramide moieties by reversed-phase HPLC and analysis bynegative-ion fast atom bombardment collisionally activated dissociationtandem mass spectrometry have allowed us to unequivocally characterizeceramide structures. In the case of GM2, 10 major ceramide subspecieswere identified: d18:1-hC16:0, d18:1-C16:0, d18:0-C16:0, d18:1-C18:0,d18:1-C20:0, d18:1-C22:0, d18:2-C24:1, d18: 1-C23:1, d18:1-C24:1,and d18:1-C24:0. Taken together with previous studies, thesefindings in human medullo-blastoma cells support the view thathigh expression and marked heterogeneity of ceramide structureare general characteristics of tumor gangliosides, moleculeswhich are shed by the tumor cells and which are biologicallyactive in vivo. medulloblastoma gangliosides ceramide structure HPLC mass spectrometry 相似文献
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25.
H. G. de Vries J. M. Collée W. P. Meeuwsen H. Scheffer L. P. Ten Kate 《Human genetics》1995,95(5):575-576
Number and sex of offspring were determined in a group of 7,841 randomly selected blood donors who were screened for the F508 mutation. We did not find any evidence for differences in number or sex ratio of offspring between F508 carriers and non-carriers. 相似文献
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J E De Vries F H Kornips J Wiegant P M Moerkerk N Senden B Schutte J P Geraedts F T Bosman J Ten Kate 《The journal of histochemistry and cytochemistry》1992,40(7):1053-1058
We describe the combination of hot banding with fluorescence in situ hybridization as a rapid and efficient method to identify integration sites of transfected DNA sequences in chromosomes. As a test system we used SW480 EJ2, a clonal cell line obtained after transfection of SW480 with pSV2neoEJ, a plasmid containing a point-mutated, c-Ha-RAS oncogene. Nick-translated probes were compared with random primed-labeled probes to evaluate their relative efficiency in fluorescence in situ hybridization. The fluorescence signals were quantified in interphase nuclei by confocal scanning laser microscopy. Nick-translated probes were found to yield better results. Hot banding followed by fluorescence in situ hybridization localized the integration site of pSV2neoEJ in SW480 EJ2 at the site of a translocation on a marker chromosome Xp+. The combination of fluorescence in situ hybridization and hot banding can be used to (a) rapidly and efficiently analyze integration sites in large numbers of transfectants, (b) assess the clonality of transfected cell lines, and (c) localize the site of integration of transfected genes in the recipient genome. 相似文献
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Of the total adenylate-kinase activity in 10-d-old barley and wheat leaves, 40–50% is localised in the chloroplasts, while in mature spinach leaves 50–70% of the enzyme is chloroplastic. The extra-chloroplastic adenylate-kinase activity is associated with the mitochondria, very little, if any, is freely soluble in the cytoplasm. The adenylate pool of the cytoplasm could have access to adenylate-kinase activity in the intermitochondrial space because of the free permeation of adenylates across the outer mitochondrial membrane. Thus the adenylate pool of the cytoplasm could be subject to adenylate-kinase equilibrium. The mitochondrial adenylate kinase appeared to the localised exclusively in the intermembrane space. 相似文献
30.
Aim Gondwanan lineages are a prominent component of the Australian terrestrial biota. However, most squamate (lizard and snake) lineages in Australia appear to be derived from relatively recent dispersal from Asia (< 30 Ma) and in situ diversification, subsequent to the isolation of Australia from other Gondwanan landmasses. We test the hypothesis that the Australian radiation of diplodactyloid geckos (families Carphodactylidae, Diplodactylidae and Pygopodidae), in contrast to other endemic squamate groups, has a Gondwanan origin and comprises multiple lineages that originated before the separation of Australia from Antarctica. Location Australasia. Methods Bayesian (beast ) and penalized likelihood rate smoothing (PLRS) (r 8s ) molecular dating methods and two long nuclear DNA sequences (RAG‐1 and c‐mos) were used to estimate a timeframe for divergence events among 18 genera and 30 species of Australian diplodactyloids. Results At least five lineages of Australian diplodactyloid geckos are estimated to have originated > 34 Ma (pre‐Oligocene) and basal splits among the Australian diplodactyloids occurred c. 70 Ma. However, most extant generic and intergeneric diversity within diplodactyloid lineages appears to post‐date the late Oligocene (< 30 Ma). Main conclusions Basal divergences within the diplodactyloids significantly pre‐date the final break‐up of East Gondwana, indicating that the group is one of the most ancient extant endemic vertebrate radiations east of Wallace’s Line. At least five Australian lineages of diplodactyloid gecko are each as old or older than other well‐dated Australian squamate radiations (e.g. elapid snakes and agamids). The limbless Pygopodidae (morphologically the most aberrant living geckos) appears to have radiated before Australia was occupied by potential ecological analogues. However, in spite of the great age of the diplodactyloid radiation, most extant diversity appears to be of relatively recent origin, a pattern that is shared with other Australian squamate lineages. 相似文献