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91.
DNA-binding proteins present in varicella-zoster virus-infected cells were identified by DNA-cellulose chromatography of radioactively labeled cell extracts. Seven virus-specific proteins, ranging in molecular weight from approximately 175,000 to 21,000, showed affinity for single- or double-stranded DNA or both. These proteins include the varicella-zoster virus major capsid protein, a phosphorylated tegument protein, and a 125,000-molecular-weight species which may be analogous to the major DNA-binding protein of herpes simplex virus. We also identified a number of DNA-binding phosphoproteins by these procedures. Finally, protein blot studies were carried out to determine whether these proteins bind preferentially to virus rather than to host cell DNA. 相似文献
92.
Marmoset phylogenetics, conservation perspectives, and evolution of the mtDNA control region 总被引:2,自引:1,他引:2
Tagliaro CH; Schneider MP; Schneider H; Sampaio IC; Stanhope MJ 《Molecular biology and evolution》1997,14(6):674-684
Marmosets (genus Callithrix) are a diverse group of platyrrhine primates
with 13-15 purported taxa, many of them considered endangered.
Morphological analyses constitute most of the basis for recognition of
these forms as distinct taxa. The purpose of this study was to provide a
molecular view, based on mitochondrial control region sequences, of the
evolutionary history of the marmosets, concomitant with a molecular
phylogenetic perspective on species diversity within the group. An
additional purpose was to provide the first comparative examination of a
complete New World monkey control region sequence with those of other
mammals. The phylogenetic analyses provide convincing support for a split
between the Atlantic forest and Amazonian marmosets, with the inclusion of
the pygmy marmoset (Cebuella pygmaea) at the base of the Amazonian clade.
The earliest branch of the Atlantic forest group was C. aurita. In the
Amazonian group, the analyses do not support the recognition of C.
humeralifer and the recently described C mauesi as distinct taxa. They do,
however, support a clear distinction between C. argentata and a strongly
supported mixed clade of C. humeralifer and C. mauesi. In the Atlantic
forest group, the phylogenetic tree suggests mixing between C. penicillata,
C. kuhli, and possibly C. jacchus. Most of the sequence features
characteristic of other mammal control regions were also evident in
marmosets, with the exception that conserved sequence blocks (CSBs) 2 and 3
were not clearly identifiable. Tandem repeat units often associated with
heteroplasmy in a variety of other mammals were not evident in the marmoset
sequences.
相似文献
93.
A method has been developed for the preparation of large single-stranded DNA sequencing templates from primary cloning plasmids or cosmids. The method utilizes the separate action of T7 Gene 6 exonuclease and exonuclease III to generate large quantities of single-stranded template for each strand of a large-cloned fragment. Since the procedure is intended for use on primary clones, it avoids the time-consuming subcloning steps associated with most sequencing programs. The procedure also has the advantage of avoiding clone instability problems associated with subcloning in M13. 相似文献
94.
Variation in the ribosomal internal transcribed spacers (ITS1 and ITS2) among eight taxa of the Mimulus guttatus species complex 总被引:1,自引:0,他引:1
The internal transcribed spacer region (ITS1 and ITS2) of the 18S-25S
nuclear ribosomal DNA sequence and the intervening 5.8S region were
sequenced from three individuals in each of eight taxa of the Mimulus
guttatus species complex. Three discrete variants, or "types," of ITS
sequences were found, among which 30%-40% of sites differed, compared with
1%-2% within types. Dot plots indicate that these types were not related by
conspicuous rearrangements or inversions. More than one ITS type was often
found in the same taxon, and two of three ITS types span species
boundaries, indicating their presence prior to speciation. These ITS
sequences showed essentially no positional homology with the nearest
sequenced relative, tomato. In contrast, the 5.8S region was relatively
unvaried, with 8 of 162 sites varied in the sample among all eight taxa.
The phylogeny inferred by the most common ITS sequence type, rooted by the
two other ITS types, agreed with isozymes in showing the distinctness of M.
nudatus, M. laciniatus, and M. tilingii from the other five taxa.
相似文献
95.
1. The light chains of human immunoglobulin were allowed to dimerize in vitro on removal of the dispersing agents acetic acid or urea. 2. On electrophoresis in polyacrylamide gel at pH8.8 the dimers yielded up to nine regularly spaced bands. This approximates to the number of electrophoretic components known to occur among the monomers. 3. Single electrophoretic components of the dimers were isolated from the gel, dissociated into monomers, and subjected as such to electrophoresis in urea-containing gels. Each gave two adjacent bands. 4. Similarly, after all the light chains as monomers had been subjected to electrophoresis in urea-containing gels, single electrophoretic components were isolated and allowed to dimerize. When examined now as dimers in the absence of urea, each component gave two adjacent bands. 5. These findings are explicable on the following basis. (a) The dimerization of the light chains is specific, at least inasmuch as it occurs between monomers of the same electrophoretic mobilities. (b) With the buffer constant, different light chains undergo different changes in net charge on being transferred from urea-containing to urea-free solution; in this way two different chains of the same initial charge can acquire a charge difference of 1. 6. Experiments with Bence-Jones proteins and other homogeneous light chains gave results substantiating the conclusions (a) and (b). 相似文献
96.
Insulin receptor internalization defect in an insulin-resistant mouse melanoma cell line 总被引:2,自引:0,他引:2
Previous studies from this laboratory demonstrated that the PG19 mouse melanoma cell line does not exhibit a biological response to insulin, whereas melanoma x mouse embryo fibroblast hybrids do respond to insulin. To investigate the molecular basis of the insulin resistance of the PG19 melanoma cells, insulin receptors from the insulin-resistant melanoma cells and insulin-sensitive fibroblast x melanoma hybrid cells were analyzed by the technique of photoaffinity labeling using the photoprobe 125I-NAPA-DP-insulin. Photolabeled insulin receptors from the two cell types have identical molecular weights as determined by SDS gel electrophoresis under reducing and nonreducing conditions, indicating that the receptors on the two cell lines are structurally similar. Insulin receptor internalization studies revealed that the hybrid cells internalize receptors to a high degree at 37 degrees C, whereas the melanoma cells internalize receptors to a very low degree or not at all. The correlation between ability to internalize insulin receptors and sensitivity to insulin action in this system suggests that uptake of the insulin-receptor complex may be required for insulin action in these cells. Insulin receptors from the two cell lines autophosphorylate in a similar insulin-dependent manner both in vitro and in intact cells, indicating that insulin receptors on the melanoma and hybrid cells have functional tyrosine protein kinase activity. Therefore, the block in insulin action in the PG19 melanoma cells appears to reside at a step beyond insulin-stimulated receptor autophosphorylation. 相似文献
97.
Bakker MF Verstappen SM Welsing PM Jacobs JW Jahangier ZN van der Veen MJ Bijlsma JW Lafeber FP;Utrecht Arthritis Cohort study group 《Arthritis research & therapy》2011,13(3):R70
Introduction
The aim of this study was to investigate whether serum biomarker levels of C2C, C1,2C, CS846, and CPII can predict the long-term course of disease activity and radiographic progression early in the disease course of rheumatoid arthritis (RA). 相似文献98.
Maza PK Straus AH Toledo MS Takahashi HK Suzuki E 《Microbes and infection / Institut Pasteur》2008,10(5):540-547
Membrane rafts are cholesterol- and sphingolipid-enriched cell membrane domains, which are ubiquitous in mammals and play an essential role in different cellular functions, including host cell-pathogen interaction. In this work, by using several approaches, we demonstrated the involvement of epithelial cell membrane rafts in adhesion process of the pathogenic fungus Paracoccidioides brasiliensis. This conclusion was supported by the localization of ganglioside GM1, a membrane raft marker, at P. brasiliensis-epithelial cell contact sites, and by the inhibition of this fungus adhesion to host cells pre-treated with cholesterol-extractor (methyl-beta-cyclodextrin, MbetaCD) or -binding (nystatin) agents. In addition, at a very early stage of P. brasiliensis-A549 cell interaction, this fungus promoted activation of Src-family kinases (SFKs) and extracellular signal-regulated kinase 1/2 (ERK1/2) of these epithelial cells. Whereas SFKs were partially responsible for activation of ERK1/2, membrane raft disruption with MbetaCD in A549 cells led to total inhibition of SFK activation. Taking together, these data indicate for the first time that epithelial cell membrane rafts are essential for P. brasiliensis adhesion and activation of cell signaling molecules. 相似文献
99.
100.
Andrea C. Tricco Jesmin Antony Noah M. Ivers Huda M. Ashoor Paul A. Khan Erik Blondal Marco Ghassemi Heather MacDonald Maggie H. Chen Lianne Kark Ezer Sharon E. Straus 《CMAJ》2014,186(15):E568-E578