Search results for "Hsp70"
showing 10 items of 206 documents
Induction of DNA strand breaks and expression of HSP70 and GRP78 homolog by cadmium in the marine sponge Suberites domuncula
1998
The marine sponge Suberites domuncula was used as a bioindicator to study the effects of cadmium on the occurrence of DNA strand breakage and on the induction of the expression of the stress biomarkers, heat shock protein 70 (HSP70) and glucose-regulated protein 78 (GRP78) homolog. The cDNA encoding GRP78 homolog from S. domuncula was isolated and characterized. The GRP78 cDNA has a length of 2.1 kb and displays characteristic features of the HSP70 family ; it encodes an aa sequence of M-r 72, 000. Exposure of S. domuncula to 1 mg/L of cadmium chloride for 24 h caused a strong(16.6-fold) increase in cadmium content to 7.7 mu g/g wet weight of sponge tissue ; after an incubation period of 6 …
Correlation between the level of the potential biomarker, heat-shock protein, and the occurrence of DNA damage in the dab, Limanda limanda: a field s…
2000
In the present study, heat-shock protein of M-r 70 kDa (HSP70), a marker of cellular stress response, was validated as a potential biomarker under field conditions. The dab, Limanda limanda (female, size greater than or equal to 25 cm, spawning maturity stage 2) was used as the indicator organism. The data on HSP level were correlated with the occurrence of DNA damage, measured in the same specimens of L. limanda, to prove the usefulness of the method. The area under investigation was the North Sea. Four locations were selected: station N01, close to Heligoland, in the North Sea; station N04 at the Dogger Bank; station N06 at the Firth of Forth; and station G08 in the English Channel. Ten a…
Cloning and sequencing of the dnaK region of Streptomyces coelicolor A3(2)
1993
Abstract The dnaK homologue of Streptomyces coelicolor A3(2) strain M145 has been cloned and sequenced. Nucleotide sequence analysis of a 2.5-kb region revealed an open reading frame (ORF) encoding a predicted DnaK protein of 618 amino acids (Mr = 66 274). The dnaK coding sequence displays extreme codon bias and shows a strong preference for CGY and GGY, for Arg and Gly codons, respectively. The predicted DnaK sequence has a high Lys:Arg ratio which is not typical of streptomycete proteins. The region immediately downstream from dnaK contains an ORF for a GrpE-like protein; the predicted start codon of grpE overlaps the last two codons of dnaK, indicating that the two genes are translationa…
Cold stress defense in the freshwater sponge Lubomirskia baicalensis
2007
The endemic freshwater sponge Lubomirskia baicalensis lives in Lake Baikal in winter (samples from March have been studied) under complete ice cover at near 0 degrees C, and in summer in open water at 17 degrees C (September). In March, specimens show high metabolic activity as reflected by the production of gametes. L. baicalensis lives in symbiosis with green dinoflagellates, which are related to Gymnodinium sanguineum. Here we show that these dinoflagellates produce the toxin okadaic acid (OA), which is present as a free molecule as well as in a protein-bound state. In metazoans OA inhibits both protein phosphatase-2A and protein phosphatase-1 (PP1). Only cDNA corresponding to PP1 could …
Evolutionary relationships of Metazoa within the eukaryotes based on molecular data from Porifera
1999
Recent molecular data provide strong support for the view that all metazoan phyla, including Porifera, are of monophyletic origin. The relationship of Metazoa, including the Porifera, to Plantae, Fungi and unicellular eukaryotes has only rarely been studied by using cDNAs coding for proteins. Sequence data from rDNA suggested a relationship of Porifera to unicellular eukaryotes (choanoflagellates). However, ultrastructural studies of choanocytes did not support these findings. In the present study, we compared amino acid sequences that are found in a variety of metazoans (including sponges) with those of Plantae, Fungi and unicellular eukaryotes, to obtain an answer to this question. We use…
Studies on heat shock proteins in sea urchin development
1999
Work on stress proteins in sea urchin embryos carried out over the last 20 years is reviewed and the following major results are described. Entire sea urchin embryos, if subjected to a rise in temperature at any postblastular stage undergo a wave of heat shock protein (hsp) synthesis and survive. If subjected to the same rise between fertilization and blastula formation, they are not yet able to synthesize hsp and die. Four clones coding for the major hsp, hsp70, have been isolated and sequenced; evidence for the existence of a heat shock factor has been provided, and a mechanism for the developmental regulation of hsp synthesis discussed. Intra- embryonic and intracellular hsp location has…
Sea urchin HSF activity in vitro and in transgenic embryos.
1997
Evidence is provided for the presence at the physiological temperature of 20 degrees C of a heat shock transcriptor factor, HSF, in the nuclei of P.lividus embryos. This HSF is able to specifically bind in vitro the heat shock element, HSE, of the promoter of the hsp70 gene i.v., as suggested by DNA-protein binding reactions and DNAse I protection assays. Upon heat-shock, at the temperature of 31 degrees C, its ability to bind the HSE units becomes much higher. The HSF activated by heat-shock drives in vivo the transcription of the beta-galactosidase reporter gene in transgenic sea urchin gastrulae. An ATF-like transcription factor, widely described in other organisms but not at all in sea …
Membrane-bound exosomal HSP70 as a biomarker for detection and monitoring of malignant solid tumours: a pilot study
2019
Abstract Background Cancer is the second leading cause of death globally. Early detection and disease management lead to a better survival rate. Consequently, discovery of novel methods in cancer early diagnosis is a field of active research. Minimally invasive liquid biopsies are generating growing interest. Circulating tumour cells (CTCs) have been identified in patients’ blood; nevertheless, these cells are rare and heterogeneous. Exosomes are extracellular nanovesicles released into the extracellular environment via the endosomal vesicle pathway and found in different body fluids. Exosomes deliver bioactive cargo such as proteins, mRNA and miRNA to recipient cells in the tumour environm…
High levels of the molecular chaperone Mdg1/ERdj4 reflect the activation state of endothelial cells
2003
Mdg1/ERdj4, a mammalian chaperone that belongs to the HSP40 protein family, has been reported to be located in the endoplasmic reticulum (ER), is induced by ER stress, and protects ER stressed cells from apoptosis. Here we show that under normal physiological conditions, Mdg1/ERdj4 is expressed at various levels in the vasculature due to different activation states of the endothelium. To elucidate the stimuli that induce ER stress and thus upregulate Mdg1/ERdj4, we investigated the effect of several endothelium specific stressors on its expression. Mdg1/ERdj4 mRNA is induced by activated macrophages, by nitric oxide (NO) and heat shock, and during terminal cell differentiation, whereas shea…
Curcumin entrapped into lipid nanosystems inhibits neuroblastoma cancer cell growth and activates Hsp70 protein
2010
Curcumin is a natural anti-cancer compound utilized on a wide variety of human cancer cell lines and animal carcinogenesis models. However, its clinical application has been limited for its minimal systemic bioavailability. Nanoparticle-based drug delivery approaches have the potential for rendering hydrophobic molecules such as curcumin dispersible in aqueous media, thus overtaking the limits of its poor solubility. In this paper, we reported the preparation and chemical-physical characterization of Nanostructured Lipid Carriers (NLC) containing curcumin, based on Imwitor, Compritol or Precirol as lipid matrix. By in vitro experiments, we have demonstrated that these nano-systems are able …