0000000000089195
AUTHOR
Hamdy M.a Hassanein
showing 11 related works from this author
Induction of Hsp70 by the Herbicide Oxyfluorfen (Goal) in the Egyptian Nile Fish, Oreochromis niloticus
1999
This paper deals with the expression of the biomarker hsp70 in the liver and kidney of the freshwater fish Oreochromis niloticus following exposure to the herbicide oxyfluorfen (Goal). Fishes were exposed to three concentrations, the 96-h LC50 (3 mg/L), the 96-h (1/2)LC50 (1.5 mg/L), and the 96-h (1/4)LC50 (0.75 mg/L) of oxyfluorfen for 6, 15, and 24 days, respectively, and samples were taken at three different time periods for each concentration. The livers responded to the herbicide by an induction of the expression of both the constitutive (hsp75; Mr 75 kDa) and the inducible (hsp73; Mr 73 kDa) hsp70 proteins. In kidney, the herbicide induced a time-dependent increase in the expression o…
Identification and Expression of the SOS Response, aidB-Like, Gene in the Marine Sponge Geodia cydonium: Implication for the Phylogenetic Relationshi…
1998
Sponges (Porifera) are the phylogenetically oldest metazoan organisms. From one member of the siliceous sponges, Geodia cydonium, the cDNA encoding a putative SOS protein, the AidB-like protein of the Ada system from bacteria, was isolated and characterized. The cDNA, GCaidB, comprises an open reading frame of 446 amino acid (aa) residues encoding a polypeptide with a calculated Mr of 49,335. This molecule shows high similarity to the bacterial AidB proteins from Mycobacterium tuberculosis and Escherichia coli and somewhat lower similarities to acyl-CoA dehydrogenases (ADHs) and acyl-CoA oxidases (AOXs). Northern blot analysis confirmed the presence of the complete transcript. The deduced s…
Expression of the human XPB/ERCC-3 excision repair gene-homolog in the sponge Geodia cydonium after exposure to ultraviolet radiation.
1998
Abstract The marine demosponge Geodia cydonium encodes a gene, termed GCXPB , which displays 62% identity to the human XPB/ERCC-3 gene that specifically corrects the repair defect in xeroderma pigmentosum and in Cockayne's syndrome. The cDNA was isolated and characterized the deduced aa sequence, XPB_GEOCY, with the calculated size of 91,541 Da comprises the characteristic domains found in the related helicases. Phylogenetic tree analysis revealed that the sponge sequence is grouped to the metazoan related XPB/ERCC-3 polypeptides. Northern Blot analyses have been performed with sponge samples collected at different depths, thus exposed to different intensities of UV sunlight in the field. T…
Induction of DNA damage and expression of heat shock protein HSP70 by polychlorinated biphenyls in the marine sponge Suberites domuncula Olivi
1999
The effects of different polychlorinated biphenyls (PCBs) including toxic coplanar non-ortho (PCB77) and non-planar mono-ortho (PCB118) and di-ortho (PCB153) congeners on the extent of DNA damage as well as on the expression of heat shock protein 70 (HSP70) were investigated in the marine sponge Suberites domuncula Olivi (Porifera; Demospongiae). A time-dependent increase in the number of DNA single-strand breaks, expressed as strand scission factor (SSF), was found after injection of a single dose of 25 mu g of PCB 118 or PCB 153 per gram wet mass of S. domuncula, using Fast Micromethod assay, which is based on the unwinding of DNA under alkaline conditions. The number of strand breaks ind…
Inhibitory effects of extracts from the marine alga Caulerpa taxifolia and of toxin from Caulerpa racemosa on multixenobiotic resistance in the marin…
1998
The invasive growth of the introduced green alga Caulerpa taxifolia, already affecting the richness and diversity of the littoral ecosystems, has become a major ecological problem in the Mediterranean Sea. Previously, we demonstrated that the water pollutant tributyltin induces apoptosis in tissue of the marine sponge Geodia cydonium at concentrations of 3 μM and higher. Here we show that exposure of G. cydonium to low (non-toxic) concentrations of Caulerpa extract or purified caulerpin (10 μg/ml) together with low doses of tributyltin (1 μM; non-toxic), results in a strong apoptotic effect. Evidence is presented that the enhancement of toxicity of tributyltin by Caulerpa extract is at leas…
17β-Estradiol-dependent regulation of chaperone expression and telomerase activity in the marine sponge Geodia cydonium
1999
It is known that species belonging to the lowest metazoan phylum, the Porifera (sponges), do not develop tumors. Sponge cells share with tumor cells of higher animals at least one characteristic; they contain high levels of telomerase activity, suggesting that they possess a high proliferation capacity. This assumption, however, has not been substantiated experimentally. In addition, sponges show a specific bauplan, leading us to postulate that they undergo apoptosis to replace a given set of cells at a given time. In the present study, 17β-estradiol (βE2) was used as a defined agent to assess its effect on both the telomerase activity and the process of apoptosis in the marine sponge Geodi…
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 …
A homolog of the putative tumor suppressor QM in the sponge Suberites domuncula: downregulation during the transition from immortal to mortal (apopto…
1999
Abstract The activation of components of the transcription factors such as AP-1 or c-jun is essential for a physiological response of metazoan cells during aging. The activity of such proto-oncoproteins is under enzymatic control. The function of c-jun is additionally modulated by the QM protein. Here, we studied the expression of the gene, encoding the QM-like protein in the sponge Suberites domuncula . These animals contain high levels of telomerase in their somatic cells. To understand the switch from telomerase-positive immortal cells to telomerase-negative mortal cells which undergo apoptosis, the expression of the QM-like gene was measured in this system. The cDNA, termed QMSD , encod…
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…
Induction of heat-shock (stress) protein gene expression by selected natural and anthropogenic disturbances in the octocoral Dendronephthya klunzinge…
2000
Previously it was found that the expression of selected heat-shock proteins is upregulated in corals after exposure to elevated temperature. We published that HSPs are suitable markers in sponges to monitor the degree of environmental stress on these animals. In the present study the heat-shock proteins (HSPs) with a molecular weight of 90 kDa have been selected to prove their potential usefulness as biomarkers under controlled laboratory conditions and in the field. The studies have been performed with the octocoral Dendronephthya klunzingeri from which the cDNA coding for HSP90 was cloned first. The expression of the HSP90 gene is upregulated by thermal stress; treatment of the animals fo…
Functional Molecular Biodiversity: Assessing the Immune Status of Two Sponge Populations (Suberites domuncula) on the Molecular Level
2004
. Porifera (sponges) are sessile filter feeders living primarily in the marine environment. In this study the population diversity of one species, the demosponge Suberites domuncula, has been investigated in an isolated area, the Limski Canal (LC) near Rovinj (Croatia; Mediterranean Sea), in comparison to that in the open sea (OS), only 10–20 km apart from the LC. The immune competence of the S. domuncula specimens was studied in response to exposure to the bacterial endotoxin LPS. The level of phosphorylation of the p38 kinase from specimens collected in LC is significantly lower than that of OS animals. To confirm the biochemical data on the molecular level, the technique of identificati…