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101.
The Yeast Bsd2-1 Mutation Influences Both the Requirement for Phosphatidylinositol Transfer Protein Function and Derepression of Phospholipid Biosynthetic Gene Expression in Yeast 总被引:1,自引:0,他引:1 下载免费PDF全文
S. Kagiwada B. G. Kearns T. P. McGee M. Fang K. Hosaka V. A. Bankaitis 《Genetics》1996,143(2):685-697
102.
Swelling and Ca2+-activated Anion Conductances in C127 Epithelial Cells Expressing WT and ΔF508-CFTR
CFTR is a chloride channel that is required for fluid secretion and salt absorption in many exocrine epithelia. Mutations
in CFTR cause cystic fibrosis. CFTR expression influences some ion channels, but the range of channels influenced, the mechanism
of the interaction and the significance for cystic fibrosis are not known. Possible interactions between CFTR and other ion
channels were studied in C127 mouse mammary epithelial cell lines stably transfected with CFTR, ΔF508-CFTR, or vector. Cell
lines were compared quantitatively using an 125I efflux assay and qualitatively using whole-cell patch-clamp recording. As expected, 125I efflux was significantly increased by forskolin only in the CFTR line, and forskolin-stimulated whole-cell currents were
time- and voltage independent. All three lines responded to hypotonic challenge with large 125I efflux responses of equivalent magnitude, and whole-cell currents were outwardly rectified and inactivated at positive voltages.
Unexpectedly, basal 125I efflux was significantly smaller in the ΔF508-CFTR cell line than in either the CFTR or control cell lines (P < 0.0001), and the magnitude of the efflux response to ionomycin was largest in the vector cell line and smallest in the
cell line expressing ΔF508-CFTR (P < 0.01). Whole-cell responses to ionomycin had a linear instantaneous I-V relation and activated at depolarizing voltages. Forskolin responses showed simple summation with responses to ionomycin
or hypotonic challenge. Thus, we found no evidence for interactions between CFTR and the channels responsible for swelling-mediated
responses. Differences were found in basal and ionomycin-stimulated efflux, but these may arise from variations in the clonally
selected cell lines that are unrelated to CFTR expression.
Received: 15 November 1995/Revised: 16 February 1996 相似文献
103.
We define the species boundaries of white-toothed shrews (genus Crocidura ) in Taiwan using karyological and morphological characteristics. Ninety-nine animals were obtained from all over Taiwan at capture rates usually less than 10%. Three species are recognized by distinct cytotypes: Crocidura attenuata tanakae 2n = 40, FN = 56; Crocidura suaveolens hosletti 2n = 40, FN = 50; Crocidura kurodai 2n = 40, FN = 54. A suite of six morphological characters diagnose the three species: shape of skull, position of incisive foramina, shape of fourth upper premolar, shape of pinna, tail vibrissae, and foot pads. A species key and notes on the life history of each species are provided. Finally, we discuss chromosomal evolution and biolgeography of Crocidura in East and South East Asia. 相似文献
104.
105.
106.
The adenovirus E4 promoter was replaced by a synthetic promoter composed of a minimal TATA box and five consensus 17-mer yeast GAL4-binding-site elements. The viral vectors, which also contained human factor IX (hFIX) cDNA driven by Rous sarcoma virus long terminal repeat in the E1 region, were then constructed and expanded in 293 cells permanently expressing GAL4/VP16 fusion protein. Viral replication and expression of adenovirus E4 genes and late genes (hexon and fiber) were evaluated in vitro in the human lung carcinoma cell line H1299. Viral replication and viral gene expression were dramatically reduced in the cells transduced by vectors with a replaced E4 promoter compared to the levels in the cells transduced by vectors with the wild-type E4 promoter. The levels of transgene (hFIX) expression remained similar between vectors with or without E4 promoter replacement. These results indicate that diminution of viral gene expression and viral replication is achievable by promoter replacement. 相似文献
107.
Fingerprinting trifoliate orange germ plasm accessions with isozymes, RFLPs, and inter-simple sequence repeat markers 总被引:7,自引:0,他引:7
D. Q. Fang M. L. Roose R. R. Krueger C. T. Federici 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,95(1-2):211-219
Trifoliate orange [Poncirus trifoliata (L.) Raf.] is frequently used as a parent in citrus rootstock breeding, but the origin and amount of genetic diversity in
germ plasm collections are poorly understood. Most accessions are self-compatible, but produce a mixture of sexual and apomictic
seedlings. Variation among 48 vegetatively propagated trifoliate orange accessions was assessed at seven isozyme loci, together
with the restriction fragment length polymorphisms (RFLPs) detected by 38 probe-enzyme combinations and the inter-simple sequence
repeat (ISSR) markers generated by 11 primers. Isozymes and RFLPs detected few polymorphisms among accessions, although genetic
analysis has shown that the common phenotype is heterozygous for four isozyme and at least four RFLP loci. ISSR amplification
generated multiple banding profiles with an average of 58 fragments/primer/accession. These fragments were repeatable across
DNA samples extracted from different trees of the same accession or extracted at different times, and across separate PCR
runs. Seventeen unique marker phenotypes were identified. The 48 trifoliate orange accessions were classified into four major
groups based on polymorphic ISSR markers. All large-flowered accessions are in group 4, while small-flowered accessions are
in group 3. Many ISSR markers segregated in progeny derived by open-pollination (probably mostly selfing) of a common accession,
indicating that these ISSR markers are also heterozygous. Accessions having identical genotypes for a large number of heterozygous
markers are unlikely to have diverged by recombination. Thus the limited divergence we detected among most accessions most
likely originated by mutation. ‘Monoembryonic’ and ‘Simmons’ differed from other accessions only in the loss of specific markers,
indicating that they originated as zygotic seedlings of individuals similar to the common genotype. Three accessions recently
introduced from China have relatively different fingerprints with 3–14 unique ISSR markers, and probably represent a much
more divergent germ plasm that may be a valuable breeding resource.
Received: 8 August 1996 / Accepted: 21 March 1997 相似文献
108.
长江华溪蟹精子超微结构的研究 总被引:1,自引:1,他引:0
透射电镜下观察长江华溪蟹成熟精子的形态和超微结构。精子呈椭球形,无鞭毛,具数条由核延伸而成的辐射臂精子。由球形的顶体,膜复合体,核杯及辐射臂组成,顶体由头帽,亚帽带,丁体囊及中央管组成。在中央管的基部发现有中心粒。核膜与质膜紧贴在一起形成了精子的界膜。 相似文献
109.
1. Transformed (TR) cell lines showed faster doubling times and higher cell densities at confluence, as well as altered morphology, changing from flat epitheloid to smaller round or bipolar shapes. Since such morphological changes are suggestive of alterations in intermediate filaments, we have analyzed the expression of both vimentin and neurofilament.2. Immunohistochemical analysis of vimentin showed a redistribution from a cytoplasmic network to a perinuclear accumulation in TR cell lines.3. Western blot analysis demonstrated that the vimentin content was decreased 60–90%. The content of the 70-kD neurofilament protein was also decreased in TR cells, but its intracellular distribution was indistinguishable from that in the control cell lines. 相似文献
110.