scholarly journals Modulation of oxidative stress by β-carotene in chicken embryo fibroblasts

1995 ◽  
Vol 73 (6) ◽  
pp. 841-850 ◽  
Author(s):  
Susan M. Lawlor ◽  
Nora M. O'brien

The ability of β-carotene to protect against oxidative stressin vitrowas assessed. Primary cultures of chicken embryo fibroblasts (CEF) were oxidatively stressed by exposure to paraquat (PQ). Activities of the antioxidant enzymes superoxide dismutase (SOD;EC1.15.1.1), catalase (CAT;EC1.11.1.6) and glutathione peroxidase (GSH-Px;EC1.11.1.9) were measured as indices of oxidative stress. CEF incubated with 0·25 mM-PQ for 18 h exhibited increased SOD and CAT activities and decreased GSH-Px activity compared with the control (P< 0·001). Incorporation of added β-carotene (0·1 μM) into 0·25 mM-PQ-treated CEF returned SOD activity to that seen in non-PQ-treated cells. β-Carotene (0·1 μM) reduced the CAT activity from that seen in PQ-treated cells and returned the GSH-Px activity to its control value thus protecting the cells against PQ-induced oxidative stress. However, at higher concentrations of β-carotene (10 μM), SOD and CAT activities increased significantly (P< 0·001) relative to non-PQ-treated cells and GSH-Px activity decreased relative to its control value. Similar trends were observed when CEF grown in β-carotene-enricbed media (0·1–10μM) were oxidatively stressed by exposure to 0·25 mM-PQ for 18 h.β-Carotene: Chicken embryo fibroblasts: Oxidative stress Antioxidant enzymes

1997 ◽  
Vol 77 (1) ◽  
pp. 133-140 ◽  
Author(s):  
Susan M. Lawlor ◽  
Nora M. O'Brien

The efficiency with which β-carotene protects against oxidative stress in chicken embryo fibrobiasts (CEF) at low O2 partial pressures was assessed. Primary cultures of CEF were grown at low O2 partial pressures and oxidatively stressed by exposure to paraquat (PQ). Activities of the antioxidant enzymes superoxide dismutase (EC 1.15.1.1; SOD), catalase (EC 1.11.1.6; CAT) and glutathione peroxidase (EC 1.11.1.9; GSH-Px) were measured as indices of oxidative stress. CEF incubated with 0·25–1·0 mM—PQ for 18 h exhibited increased SOD and CAT activities compared with non-PQ-treated control cells (P < 0·001). No cytotoxicity as indicated by lactate dehydrogenase (EC 1.1.1.27; LDH) release was observed at PQ concentrations below 2·0 mM. Incorporation of added β-carotene into 0·25 mM-PQ-treated cells prevented the PQ-induced increases in SOD and CAT, and activities were similar to those seen in non-PQ-treated control cells. GSH-Px activity decreased relative to its control value on exposure to 0·25 mM-PQ and β-carotene prevented this decrease in a dose-dependent manner. The proportion of LDH released from the CEF treated with β-carotene remained below the control value of 2·5% at all times.


1987 ◽  
Vol 7 (3) ◽  
pp. 1139-1147
Author(s):  
J W Ryder ◽  
J A Gordon

We have compared the tyrosine kinase activity of pp60c-src isolated from intact chicken embryo fibroblasts treated with micromolar sodium orthovanadate for 4 h and from untreated cells. We found an approximate 50% reduction in both autophosphorylation of pp60c-src and phosphorylation of casein when examined in the immune complex kinase assay. The reduction of in vitro enzymatic activity correlated with a vanadate-induced increase in in vivo phosphorylation of pp60c-src at the major site of tyrosine phosphorylation in the carboxyl-terminal half of the molecule and at serine in the amino-terminal half of the molecule. Our observations in vivo and those of Courtneidge in vitro (EMBO J. 4:1471-1477, 1985) suggest that vanadate may enhance a cellular regulatory mechanism that inhibits the activity of pp60c-src in normal cells. A likely candidate for this mechanism is phosphorylation at a tyrosine residue distinct from tyrosine 416, probably tyrosine 527 in the carboxyl-terminal sequence of amino acids unique to pp60c-src. The regulatory role, if any, of serine phosphorylation in pp60c-src remains unclear. The 36-kilodalton phosphoprotein, a substrate of pp60v-src, showed a significant phosphorylation at tyrosine after treatment of normal chicken embryo fibroblasts with vanadate. Assuming that pp60c-src is inhibited intracellularly by vanadate, either another tyrosine kinase is stimulated by vanadate (e.g., a growth factor receptor) or the 36-kilodalton phosphoprotein in normal cells is no longer rapidly dephosphorylated by a tyrosine phosphatase in the presence of vanadate.


1993 ◽  
Vol 13 (9) ◽  
pp. 5225-5232 ◽  
Author(s):  
X Liu ◽  
L E Marengere ◽  
C A Koch ◽  
T Pawson

Fibroblasts transformed by v-src or by related oncogenes encoding activated tyrosine kinases contain elevated levels of polyphosphoinositides with phosphate at the D-3 position of the inositol ring, as a result of the activation of phosphatidylinositol (PI) 3'-kinase. v-src-transformed cells also contain increased levels of PI 3'-kinase activity immunoprecipitable with anti-phosphotyrosine antibodies; furthermore, PI 3'-kinase can be detected in association with the v-Src tyrosine kinase. To identify regions of v-Src that can interact with PI 3'-kinase, the v-Src SH2 and SH3 domains were expressed in bacteria and incubated with lysates of normal chicken embryo fibroblasts. In vitro, the v-Src SH3 domain, but not the SH2 domain, bound PI 3'-kinase in lysates of uninfected chicken embryo fibroblasts. Substitutions of two highly conserved SH3 residues implicated in ligand binding abolished the ability of the v-Src SH3 domain to associate with PI 3'-kinase. Furthermore, the v-Src SH3 domain bound in vitro to the amino-terminal region of the p85 alpha subunit of PI 3'-kinase. These results suggest that the v-Src SH3 domain may mediate an interaction between the v-Src tyrosine kinase and PI 3'-kinase, by direct binding to p85.


1985 ◽  
Vol 5 (5) ◽  
pp. 949-956
Author(s):  
U Bond ◽  
M J Schlesinger

Clones containing heat-inducible mRNA sequences were selected from a cDNA library prepared from polyadenylated RNA isolated from heat-shocked chicken embryo fibroblasts. One recombinant DNA clone, designated clone 7, hybridized to a 1.2-kilobase RNA that was present in normal cells and increased fivefold during heat shock. Clone 7 also hybridized to an RNA species of 1.7 kilobases that was present exclusively in heat-shocked cells. In vitro translation of mRNA hybrid selected from clone 7 produced a protein product with a molecular weight of approximately 8,000. Increased synthesis of a protein of similar size was detected in chicken embryo fibroblasts after heat shock. DNA sequence analysis of clone 7 indicated its protein product has amino acid sequences identical to bovine ubiquitin. In addition, clone 7 contains tandem copies of the ubiquitin sequences contiguous to each other with no untranslated sequences between them. We discuss some possible roles for ubiquitin in the heat shock response.


1986 ◽  
Vol 6 (5) ◽  
pp. 1545-1551
Author(s):  
S Kornbluth ◽  
F R Cross ◽  
M Harbison ◽  
H Hanafusa

The middle T antigen of polyomavirus transformed primary chicken embryo fibroblasts when expressed from a replication-competent avian retrovirus. This in vitro-constructed retrovirus, SRMT1, is a variant of Rous sarcoma virus that encodes the middle T antigen in place of v-src. Inoculation of SRMT1 into 1-week-old chickens rapidly induced hemangiomas and hemangiosarcomas. As shown with mammalian cells infected with polyomavirus, polyomavirus middle T antigen appears to be associated with p60c-src in chicken cells infected with SRMT1. When lysates of SRMT1-infected cells immunoprecipitated with either a monoclonal antibody against p60src or anti-T serum were assayed in an in vitro kinase reaction, the middle T antigen was heavily phosphorylated. To see whether an excess of p60c-src could alter the extent of phosphorylation of the middle T protein or the process of cell transformation by middle T, cells were doubly infected with SRMT1 and NY501, a virus which overexpresses p60c-src. Doubly infected chicken embryo fibroblasts transformed with the same kinetics and were morphologically indistinguishable from chicken embryo fibroblasts infected with SRMT1 alone. Phosphorylation of the middle T antigen was elevated two- to fivefold relative to cells infected only with SRMT1.


1988 ◽  
Vol 8 (4) ◽  
pp. 1657-1663 ◽  
Author(s):  
J P Trempe ◽  
Y I Lindstrom ◽  
M Leffak

We used an in vitro nuclear runoff replication assay to analyze the direction of replication of the active and inactive histone H5 genes in avian cells. In embryonic erythrocytes the transcribed histone H5 gene displayed sensitivity to endogenous nuclease cleavage. In contrast, this gene was insensitive to endogenous nuclease digestion under the same conditions in nuclei of the lymphoblastoid cell line MSB-1, and histone H5 gene transcripts were not detectable by dot-blot analysis of MSB-1 cell RNA. When nuclei were isolated from embryonic erythrocytes and incubated with bromodeoxyuridine triphosphate, runoff replication from endogenous nuclease cleavage sites led to a relative enrichment for fragments near the 3' end of the histone H5 gene in the density-labeled DNA. In nuclei of MSB-1 cells or chicken embryo fibroblasts, however, runoff replication from restriction enzyme-cut sites (or induced endogenous nuclease-cut sites in MSB-1 nuclei) led to a relative enrichment for fragments near the 5' end of the H5 gene in dense DNA. Based on the enhanced incorporation of bromodeoxyuridine into origin-distal regions of DNA during the in vitro runoff replication assay, we conclude that the active histone H5 gene in embryonic erythrocytes is preferentially replicated in the transcriptional direction from an origin in the 5'-flanking DNA, whereas its inactive counterparts in MSB-1 cells and chicken embryo fibroblasts are preferentially replicated in the opposite direction.


2012 ◽  
Vol 56 (4) ◽  
pp. 441-446 ◽  
Author(s):  
Jowita Samanta Niczyporuk ◽  
Grzegorz Woźniakowski ◽  
Elżbieta Samorek-Salamonowicz ◽  
Hanna Czekaj

Abstract The aim of the study was to determine the influence of simultaneous infection of chicken embryo fibroblasts (CEF) with different doses of adenovirus field strain serotype 7 (FAdV-7 JN-5/10j) and turkey herpesvirus strain FC126 (FC126 HVT) on replication of the herpesvirus in in vitro cultures. Three experiments were performed: simultaneous infection of CEF with adenovirus and HVT; inoculation of CEF culture with adenovirus, followed by infection with HVT after 24 h; and inoculation of CEF with HVT, followed by the infection with adenovirus 24 h later. In order to detect the presence of HVT and adenovirus strains in CEF culture, SORF 1 and hexon genes were determined, respectively. The infection with adenovirus lowered replication of FC126 HVT in chicken embryo fibroblast.


Virus Genes ◽  
2007 ◽  
Vol 36 (1) ◽  
pp. 35-44 ◽  
Author(s):  
Maria Beatriz Borges ◽  
Elena Caride ◽  
Alfredo V. Jabor ◽  
José Marcus N. Malachias ◽  
Marcos S. Freire ◽  
...  

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