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1.
Codon usage in the vertebrate hemoglobins and its implications 总被引:2,自引:0,他引:2
A study of codon usage in vertebrate hemoglobins revealed an evolutionary
trend toward elevated numbers of CpG codon boundary pairs in mammalian
hemoglobin alpha genes. Selection for CpG codon boundaries countering the
generally observed CpG suppression is strongly suggested by these data.
These observations parallel recently published experimental results that
indicate that constitutive expression of the human alpha-globin gene
appears to be determined by regulatory information encoded within the
structural gene. The possibility is raised that, in the absence of
selection, CpG decay can be used to date the evolutionary origin of a
mammalian alpha pseudogene from its active alpha gene.
相似文献
2.
Manessi A Papaefstathiou GS Raptopoulou CP Terzis A Zafiropoulos TF 《Journal of inorganic biochemistry》2004,98(12):2052-2062
As part of our interest into the bioinorganic chemistry of gallium, gallium(III) complexes of the peptide ligand N-(2-(4-imidazolyl)ethyl)pyridine-2-carboxamide (pypepH2) resembling a fragment of the metal-binding domain of bleomycins (BLMs), have been isolated. Reaction of pypepH2 with (Et4N)[GaCl4] and Ga(acac)3 [acac- is the acetylacetonate(-1) ion] affords the mononuclear complex [Ga(pypepH)2]Cl.2H2O (1) and the tetranuclear complex [Ga4(acac)4(pypep)4].4.4H2O (2), respectively. Both complexes were characterized by single-crystal X-ray crystallography, IR spectroscopy and thermal decomposition data. The pypepH- ion in 1 behaves as a N(pyridyl), N(deprotonated amide), N(pyridine-type imidazole) chelating ligand. The doubly deprotonated pypep2- ion in 2 behaves as a N(pyridyl), N(deprotonated amide), N(imidazolate), N'(imidazolate) mu2 ligand and binds to one Ga(III) atom at its pyridyl, amide and one of the imidazolate nitrogens, and to a second metal ion at the other imidazolate nitrogen; a chelating acac- ligand completes six coordination at each Ga(III) centre. The IR data are discussed in terms of the nature of bonding and known structures. The 1H NMR spectrum of 1 suggests that the cation of the complex maintains its integrity in dimethylsulfoxide (DMSO) solution. Complexes 1 and 2 are the first synthetic analogues of metallobleomycins with gallium(III). 相似文献
3.
Baritaki S Zafiropoulos A Georgopoulos E Souris S Krambovitis E 《Cancer immunology, immunotherapy : CII》2001,50(2):109-114
It has been demonstrated that IgG antibodies can be generated to self-antigen peptides as well as against viral antigens
by an antigen-specific in vitro immunization system of resting human peripheral B-lymphocytes. Using a synthetic peptide from
the consensus variable tandem-repeat region of the MUC3 mucin (TSSITTTGTTSHSTPSP) as the B cell epitope, we immunized blood
donor B-lymphocytes in vitro and tested for MUC3-specific antibodies by ELISA. After the primary activation step all antibodies
were IgM. At the end of the secondary immunization step we obtained 1.8% (21/1138) of the cultures with IgG-switched antibodies.
In a competitive inhibition ELISA using the MUC1, MUC2, MUC3, MUC4 and PIP2 peptides, only one culture (F8.1) gave satisfactory
specific inhibition. Using this antibody in fluorometric studies, it stained cells from two colon carcinoma cell lines predominantly
in the cytoplasm, whereas those from a breast cancer cell line stained predominantly the cell surface. In a preliminary immunohistological
evaluation with formalin-fixed sections, the antibody appeared to moderately stain colon sections, but not breast sections
or lymph node. This method of in vitro immunization may be a useful tool in generating IgG antibodies specific to self-antigens
and could find applications in tumour targeting and immunotherapy.
Received: 12 October 2000 / Accepted: 11 January 2001 相似文献
4.
G. Chatzinikolaou D. Nikitovic A. Berdiaki A. Zafiropoulos P. Katonis N. K. Karamanos† G. N. Tzanakakis 《Cell proliferation》2010,43(1):9-18
Objectives: Heparin acts as an extracellular stimulus capable of activating major cell signalling pathways. Thus, we examined the putative mechanisms utilized by heparin to stimulate HT29, SW1116 and HCT116 colon cancer cell growth.
Materials and methods: Possible participation of the mitogen-activated protein kinase (MAPK) cascade on heparin-induced HT29, SW1116 and HCT116 colon cancer cell growth was evaluated using specific MAPK cascade inhibitors, Western blot analysis, real-time quantitative PCR and FACS apoptosis analysis.
Results: Treatment with a highly specific p38 kinase inhibitor, SB203580, significantly (50–70%) inhibited heparin-induced colon cancer cell growth, demonstrating that p38 MAPK signalling is involved in their heparin-induced proliferative response. This was shown to be correlated with increased (up to 3-fold) phosphorylation of 181/182 threonine/tyrosine residues on p38 MAP kinase. Furthermore, heparin inhibited cyclin-dependent kinase inhibitor p21 WAF1 / CIP1 and p53 tumour suppressor gene and protein expression up to 2-fold or 1.8-fold, respectively, and stimulated cyclin D1 expression up to 1.8-fold, in these cell lines through a p38-mediated mechanism. On the other hand, treatment with heparin did not appear to affect HT29, SW1116 and HCT116 cell levels of apoptosis.
Conclusions: This study demonstrates that an extracellular glycosaminoglycan, heparin, finely modulates expression of genes crucial to cell cycle regulation through specific activation of p38 MAP kinase to stimulate colon cancer cell growth. 相似文献
Materials and methods: Possible participation of the mitogen-activated protein kinase (MAPK) cascade on heparin-induced HT29, SW1116 and HCT116 colon cancer cell growth was evaluated using specific MAPK cascade inhibitors, Western blot analysis, real-time quantitative PCR and FACS apoptosis analysis.
Results: Treatment with a highly specific p38 kinase inhibitor, SB203580, significantly (50–70%) inhibited heparin-induced colon cancer cell growth, demonstrating that p38 MAPK signalling is involved in their heparin-induced proliferative response. This was shown to be correlated with increased (up to 3-fold) phosphorylation of 181/182 threonine/tyrosine residues on p38 MAP kinase. Furthermore, heparin inhibited cyclin-dependent kinase inhibitor p21
Conclusions: This study demonstrates that an extracellular glycosaminoglycan, heparin, finely modulates expression of genes crucial to cell cycle regulation through specific activation of p38 MAP kinase to stimulate colon cancer cell growth. 相似文献
5.
Zafiropoulos GG Weiss O Kasaj A Willershausen B Plancak D 《Collegium antropologicum》2006,30(4):951-957
Aggressive periodontitis is characterized by rapid attachment and bone loss with no underlying systemic disease and is associated with specific bacteria like Actinobacillus actinomycetemcomitans (Aa) and Porphyromonas gingivalis (Pg). In this case series 25 patients were diagnosed with aggressive periodontitis by the aid of DNA probes for Aa and Pg and other periodontal pathogens. The use of DNA probes for the detection of periodontal pathogens may aid in the diagnosis and treatment of aggressive periodontitis. Clinical experience suggests that lowering periodontal pathogens to undetectable levels could improve the long-term stability of periodontal health. 相似文献
6.
Visualization by live-cell microscopy of disruption of ND10 during herpes simplex virus type 1 infection 下载免费PDF全文
ND10 structures are disrupted during herpes simplex virus type 1 (HSV-1) infection by viral regulatory protein ICP0. The significance of this effect remains controversial, partly because of a report that high-level expression of the major ND10 promyelocytic leukemia (PML) protein precludes ND10 disruption yet does not inhibit HSV-1 infection. Here we demonstrate dramatic reorganization of ND10 during HSV-1 infection by live-cell microscopy, even in the presence of overexpressed PML. 相似文献
7.
Zafiropoulos A Tsentelierou E Linardakis M Kafatos A Spandidos DA 《The international journal of biochemistry & cell biology》2005,37(2):409-415
Loss of genomic rDNA has been associated with cellular and organismal ageing. The rDNA locus in humans comprises multiple copies of the 5.8S, 28S and 18S genes. Aim of the present study was to test the effect of aging on the copy number of the three rDNA genes individually in post-mitotic human tissue. We utilized real time polymerase chain reaction relative quantification to measure the copy number of 5.8S, 28S and 18S rDNA genes individually. We obtained adipose tissue from 120 male individuals aged from 9 to 94 years. The available data of each subject corresponding to the time of tissue sampling included: age, height, weight and calculated body mass index. Each rDNA gene was directly tested with Pearson correlation against age and body mass index. We found a significant negative correlation of the gene copy of 5.8S (P < 0.001) and 28S (P < 0.003) with age. Interestingly 18S gene copy displayed a different pattern with no statistically significant correlation with age. Conversely, we observed a significant negative correlation of the 18S gene copy with body mass index (P = 0.004) and a marginally non-significant negative correlation of the 5.8S (P = 0.097) gene copy with body mass index. In summary our results indicate that the rDNA recombination events in humans can be differentially targeted and regulated in response to ageing and/or fat accumulation. The proposed model generates possible implications regarding the effects of each rDNA gene loss in cell function as well as the mechanism of recombination targeting. 相似文献
8.
Proliferating cell nuclear antigen (PCNA) as a proliferative marker during embryonic and adult zebrafish hematopoiesis 总被引:4,自引:1,他引:3
Leung AY Leung JC Chan LY Ma ES Kwan TT Lai KN Meng A Liang R 《Histochemistry and cell biology》2005,124(2):105-111
We investigated the expression of proliferative cell nuclear antigen (PCNA) in zebrafish to delineate the proliferative hematopoietic
component during adult and embryonic hematopoiesis. Immunostaining for PCNA and enhanced green fluorescence protein (eGFP)
was performed in wild-type and fli1-eGFP (endothelial marker) and gata1-eGFP (erythroid cell marker) transgenic fish. Expression
of PCNA mRNA was examined in wild-type and chordin morphant embryos. In adult zebrafish kidney, the renal tubules are surrounded
by endothelial cells and it is separated into hematopoietic and excretory compartments. PCNA was expressed in hematopoietic
progenitor cells but not in mature neutrophils, eosinophils or erythroid cells. Some PCNA+ cells are scattered in the hematopoietic
compartment of the kidney while others are closely associated with renal tubular cells. PCNA was also expressed in spermatogonial
stem cells and intestine crypts, consistent with its role in cell proliferation and DNA synthesis. In embryos, PCNA is expressed
in the brain, spinal cord and intermediate cell mass (ICM) at 24 h-post fertilization. In chordin morphants, PCNA is significantly
upregulated in the expanded ICM. Therefore, PCNA can be used to mark cell proliferation in zebrafish hematopoietic tissues
and to identify a population of progenitor cells whose significance would have to be further investigated. 相似文献
9.
Baritaki S Zafiropoulos A Sioumpara M Politis M Spandidos DA Krambovitis E 《Biochemical and biophysical research communications》2002,298(4):574-580
We have reported that the principal neutralizing domain of V3 of the HIV-1 gp120 induces an antigen-specific activation apoptosis of responding effector CD4+ T lymphocytes, a phenomenon inhibited by RANTES, an agonist of CCR5. Here, addressing the question of how a hypervariable region could induce such a selective reaction, we demonstrated that the magnitude of the activation phase was dependent on the number of basic amino acids present in the V3 peptide, an observation confirmed by using V3 peptides with appropriate basic amino acid substitutions. The relative position of the amino acids in the V3 peptide did not affect the biological phenomenon. Using surface plasmon resonance biosensor analysis, we also provided direct evidence of the influence of basic amino acids in the interaction between V3 and the amino terminal domain of CCR5. Sulphation of tyrosines in the CCR5 peptide was essential. Our results confirm gp120 modelling predictions and demonstrate simple molecular ionic interactions as capable of affecting key cell events, the wider biological implications of which need to be further explored. 相似文献
10.
Sheung-Tak Cheng Rosanna WL Lau Emily PM Mak Natalie SS Ng Linda CW Lam Helene H Fung Julian CL Lai Timothy Kwok Diana TF Lee 《Trials》2012,13(1):1-10