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1.
2.
Ribosomal DNA and ITS-2 sequence comparisons as a tool for predicting genetic relatedness 总被引:14,自引:0,他引:14
The determination of the secondary structure of the internal transcribed spacer (ITS) regions separating nuclear ribosomal
RNA genes of Chlorophytes has improved the fidelity of alignment of nuclear ribosomal ITS sequences from related organisms.
Application of this information to sequences from green algae and plants suggested that a subset of the ITS-2 positions is
relatively conserved. Organisms that can mate are identical at all of these 116 positions, or differ by at most, one nucleotide
change. Here we sequenced and compared the ITS-1 and ITS-2 of 40 green flagellates in search of the nearest relative to Chlamydomonas reinhardtii. The analysis clearly revealed one unique candidate, C. incerta. Several ancillary benefits of the analysis included the identification of mislabelled cultures, the resolution of confusion
concerning C. smithii, the discovery of misidentified sequences in GenBank derived from a green algal contaminant, and an overview of evolutionary
relationships among the Volvocales, which is congruent with that derived from rDNA gene sequence comparisons but improves
upon its resolution. The study further delineates the taxonomic level at which ITS sequences, in comparison to ribosomal gene
sequences, are most useful in systematic and other studies.
Received: 14 February 1997 / Accepted: 28 March 1997 相似文献
3.
Production and characterization of functional domains of human fibronectin expressed in Escherichia coli. 总被引:4,自引:0,他引:4
F Kimizuka Y Taguchi Y Ohdate Y Kawase T Shimojo K Hashino I Kato K Sekiguchi K Titani 《Journal of biochemistry》1991,110(2):284-291
An efficient expression system was constructed in Escherichia coli that produced a 33-kDa fragment, C-274, of human fibronectin with a strong cell-adhesive activity. The entire sequence of the heparin-binding domain with 271 amino acids, H-271, was also expressed. Deletion analysis of the type III repeats showed that the heparin-binding site was at type III-13. The cell-adhesive activity of a fusion protein, CH-271, containing the cell- and the heparin-binding domains was twice that of C-274 when BHK but not B16-F10 melanoma cells were tested; H-271 alone was inactive. Recombinant proteins containing the CS1 sequence of the IIICS region were more active than C-274 and CH-271 with B16-F10. However, H-296, which contained both H-271 and CS1, was almost inactive with BHK. CH-296, which contained CS1 at the C-terminus of CH-271, was more active with B16-F10 than H-296 and C-CS1, which was produced by the deletion of H-271 from CH-296. Thus, the cell-binding domain was active with both kinds of cells. The heparin-binding domain promoted the adhesion of both kinds of cells only when linked to the cell-binding domain or CS1. CS1 was specific for the adhesion of B16-F10 but was not essential. 相似文献
4.
K Hashino T Shimojo F Kimizuka I Kato T Maeda K Sekiguchi K Titani 《Journal of biochemistry》1992,112(4):547-551
A new artificial cell adhesive protein was engineered by grafting the Arg-Gly-Asp (RGD) sequence, the minimal recognition signal of fibronectin for interaction with integrins, to a calpastatin segment by in vitro mutagenesis. The mutagenized protein showed cell adhesive activity in addition to calpain inhibitory activity. The RGD signal grafted to the calpastatin segment was recognized by the vitronectin receptor but not by the fibronectin receptor. 相似文献
5.
An efficient expression system was constructed for C-EGF, a fusion protein made of a fragment of the cell-binding domain of human fibronectin (FN) bound with epidermal growth factor (EGF). C-EGF was produced in Escherichia coli HB101 cells carrying the recombinant plasmid pCE102 as inclusion bodies, which were solubilized and refolded after purification. C-EGF had both cell-adhesive and EGF activities, so it might be more effective than EGF in therapeutic applications. This fusion system would be useful for the construction of a recombinant drug delivery system for cells that have fibronectin receptors (integrins). 相似文献
6.
7.
CC Cheng N Lu CL Peng CC Chang FD Mai LY Chen MH Liao WM Wang J Chang 《Proteomics》2012,12(15-16):2584-2597
The survivals of gastric cancer (GC) patients are associated with early diagnosis and effective treatments. Therefore, it is urgent for the discovery of early GC biomarkers and tumor-targeting therapeutics. The aim of this study was to uncover putative tissue biomarkers of GC using 2D DIGE and then apply one of these specific markers in GC treatment. We found three putative biomarkers of GC with significant differences in expression level compared to adjacent normal tissue, including glucose-regulated protein 78 (GRP78) and glutathione s-transferase pi (GSTpi) with increased expression level, and alpha-1 antitrypsin (A1AT) with reduced expression level. The overexpressed GRP78 was used as a targeted protein for guiding the drugs to tumor cells, leading to more effective treatment for GC xenografts. Our results demonstrated that the designated GRP78-binding peptide based on the sequence, WIFPWIQL, was selectively prone to recognize and bind to GC MKN45 cells in vitro, and also improve the delivery efficiency of polymeric micelles-encapsulated drugs into tumor cells and displayed better therapeutic outcome in experimental animals. This strategy of GRP78-mediated drug targeting system may bring chemotherapeutic drugs with more precise targeting to tumor cells, leading to minimize side effects on patients after chemotherapy. 相似文献
8.
Zhen-Yu Zhang Yin Mai Hao Yang Pei-Yue Dong Xue-Li Zheng Gong-She Yang 《Molecular and cellular biochemistry》2014,395(1-2):53-64
The process of preadipocytes differentiation plays a vital role in adipose tissue expansion and many factors are involved in this event. Cathepsin B (CTSB), secreted from lysosome, has been reported in regulating a variety of physiological processes. In this study, we demonstrated CTSB promotes lipid accumulation and adipogenic genes expression in porcine primary preadipocytes by degrading fibronectin (Fn), a key component of extracellular matrix. Lithium chloride (LiCl) is an activator of Wnt/β-catenin signaling through stabilizing β-catenin. We found that CTSB can relieve the anti-adipogenic effects of LiCl, indicating that CTSB could impact Wnt/β-catenin signaling pathway. Interestingly, Fn is an important target gene of Wnt/β-catenin. So we considered that CTSB promote preadipocytes differentiation by suppressing these two pathways. 相似文献
9.
Hans Knecht Silke Brüderlein Silke Wegener Daniel Lichtensztejn Zelda Lichtensztejn Bruno Lemieux Peter Möller Sabine Mai 《BMC cell biology》2010,11(1):99
Background
In cancer cells the three-dimensional (3D) telomere organization of interphase nuclei into a telomeric disk is heavily distorted and aggregates are found. In Hodgkin's lymphoma quantitative FISH (3D Q-FISH) reveals a major impact of nuclear telomere dynamics during the transition form mononuclear Hodgkin (H) to diagnostic multinuclear Reed-Sternberg (RS) cells. In vitro and in vivo formation of RS-cells is associated with the increase of very short telomeres including "t-stumps", telomere loss, telomeric aggregate formation and the generation of "ghost nuclei". 相似文献10.
Selectivity of Ferric Enterobactin Binding and Cooperativity of Transport in Gram-Negative Bacteria 总被引:1,自引:5,他引:1 下载免费PDF全文
Padmamalini Thulasiraman Salete M. C. Newton Jide Xu Kenneth N. Raymond Christine Mai Angela Hall Marjorie A. Montague Phillip E. Klebba 《Journal of bacteriology》1998,180(24):6689-6696
The ligand-gated outer membrane porin FepA serves Escherichia coli as the receptor for the siderophore ferric enterobactin. We characterized the ability of seven analogs of enterobactin to supply iron via FepA by quantitatively measuring the binding and transport of their 59Fe complexes. The experiments refuted the idea that chirality of the iron complex affects its recognition by FepA and demonstrated the necessity of an unsubstituted catecholate coordination center for binding to the outer membrane protein. Among the compounds we tested, only ferric enantioenterobactin, the synthetic, left-handed isomer of natural enterobactin, and ferric TRENCAM, which substitutes a tertiary amine for the macrocyclic lactone ring of ferric enterobactin but maintains an unsubstituted catecholate iron complex, were recognized by FepA (Kd ≈ 20 nM). Ferric complexes of other analogs (TRENCAM-3,2-HOPO; TREN-Me-3,2-HOPO; MeMEEtTAM; MeME-Me-3,2-HOPO; K3MECAMS; agrobactin A) with alterations to the chelating groups and different net charge on the iron center neither adsorbed to nor transported through FepA. We also compared the binding and uptake of ferric enterobactin by homologs of FepA from Bordetella bronchisepticus, Pseudomonas aeruginosa, and Salmonella typhimurium in the native organisms and as plasmid-mediated clones expressed in E. coli. All the transport proteins bound ferric enterobactin with high affinity (Kd ≤ 100 nM) and transported it at comparable rates (≥50 pmol/min/109 cells) in their own particular membrane environments. However, the FepA and IroN proteins of S. typhimurium failed to efficiently function in E. coli. For E. coli, S. typhimurium, and P. aeruginosa, the rate of ferric enterobactin uptake was a sigmoidal function of its concentration, indicating a cooperative transport reaction involving multiple interacting binding sites on FepA. 相似文献