scholarly journals A role for glyceraldehyde-3-phosphate dehydrogenase in the development of thermotolerance in Xenopus laevis embryos.

1988 ◽  
Vol 107 (5) ◽  
pp. 1901-1909 ◽  
Author(s):  
R W Nickells ◽  
L W Browder
Keyword(s):  
Enzyme Activity ◽  
Heat Shock ◽  
Xenopus Laevis ◽  
Heat Shock Protein ◽  
Specific Activity ◽  
Glycolytic Enzyme ◽  
Polyacrylamide Gels ◽  
Different Temperatures ◽  
Peptide Maps ◽  
Xenopus Laevis Embryos

During heat shock, Xenopus laevis embryos exhibit an increase in the rate of accumulation of lactate and a loss of ATP relative to non-heat-shocked control embryos. These results suggest that heat shock stimulates a shift in energy metabolism to anaerobic glycolysis while at the same time causing an increase in the demand for ATP. We have evidence indicating that the embryo may meet such demands placed on it by increasing the levels of some glycolytic enzymes. In this report, we show that heat shock stimulates increases in the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase [( EC 1.2.1.12] GAPDH). The specific activity of GAPDH shows a significant increase after heat shock, which correlates with the accumulation of GAPDH in heat-shocked embryos as detected by immunoblotting. Increases in GAPDH-specific activity are variable, however, and are inversely proportional to the levels of specific activity in control embryos; i.e., constitutive enzyme activity. We further analyzed the heat-enhanced accumulation of GAPDH by electrophoretically separating GAPDH isozymes on nondenaturing polyacrylamide gels. Control embryos exhibit a single isozyme of GAPDH, whereas heat-shocked embryos exhibit two isozymes of GAPDH. When these isozymes are labeled with [35S]methionine, separated by nondenaturing gel electrophoresis, and analyzed by fluorography, a heat-shock protein is found to comigrate with the isozyme unique to the heat-shocked sample. Enzyme activity assays at different temperatures suggest that this isozyme has optimum enzymatic activity only at heat-shock temperatures. We have correlated a 35-kD heat-shock protein (hsp35) with GAPDH using the following evidence: this hsp comigrates with GAPDH on one-dimensional SDS polyacrylamide gels; heat-enhanced increases in GAPDH specific activity correlate with hsp35 synthesis; and hsp35 and GAPDH have similar peptide maps. This relationship also provides a compelling explanation for the restriction of hsp35 synthesis to the vegetal hemisphere cells of heat-shocked early gastrulae reported previously (Nickells, R. W., and L. W. Browder. 1985. Dev. Biol. 112:391-395).

Factors influencing the heat shock response of Xenopus laevis embryos

1989 ◽  
Vol 67 (10) ◽  
pp. 687-695 ◽  
Author(s):  
Robert W. Nickells ◽  
Leon W. Browder ◽  
Theresa I. Wang
Keyword(s):  
Heat Shock ◽  
Heat Shock Proteins ◽  
Xenopus Laevis ◽  
Heat Shock Response ◽  
Specific Activity ◽  
Developmental Regulation ◽  
Glycolytic Enzyme ◽  
Shock Response ◽  
Shock Proteins ◽  
Xenopus Laevis Embryos

We have further characterized the heat shock response of Xenopus laevis embryos. Xenopus embryos respond to heat shock by consistently synthesizing four major heat shock proteins (hsps) of 62, 70, 76, and 87 kilodaltons. In addition to these hsps, heat-shocked embryos also exhibit the synthesis of several minor hsps. The synthesis of these hsps is often variable. We have monitored the effects of different temperatures and lengths of heat shock on the pattern and intensity of hsp synthesis. In general, the four major hsps are induced more strongly at higher temperatures and during increasing intervals of heat shock. The temperature and duration of heat shock can affect the synthesis of the minor hsps, however. Some hsps are synthesized at lower temperatures only (i.e., below 37 °C), whereas others are synthesized only at higher temperatures (i.e., above 37 °C). We have extensively examined the characteristics of hsp 35 synthesis, one of the most variably synthesized hsps. This hsp is characteristically synthesized at temperatures above 35 °C and usually during the first 40 min of heat shock, after which it becomes undetectable. In some experiments, its synthesis is restimulated during later intervals of heat shock. Hsp 35 is also under developmental regulation. It is not synthesized by heat-shocked embryos until the late blastula to early gastrula stage. After this brief period of inducibility, its synthesis is dramatically reduced in mid- to late gastrulae, but reappears in heat-shocked neurulae. We have previously demonstrated that hsp 35 is related to the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The induction of hsp 35 synthesis is inversely correlated with the constitutive levels of GAPDH specific activity. In this paper we document further correlations between the synthesis of hsp 35 and GAPDH specific activity during early Xenopus development.Key words: glyceraldehyde-3-phosphate dehydrogenase (GAPDH), pyruvate kinase (PK), heat shock proteins (hsps), heat shock response, thermotolerance, Xenopus laevis.

Examination of heat shock protein mRNA accumulation in early Xenopus laevis embryos

1987 ◽  
Vol 65 (2) ◽  
pp. 87-94 ◽  
Author(s):  
J. J. Heikkila ◽  
N. Ovsenek ◽  
P. Krone
Keyword(s):  
Heat Shock ◽  
Xenopus Laevis ◽  
Heat Shock Protein ◽  
Incubation Temperature ◽  
Effect Of Temperature ◽  
Continuous Exposure ◽  
Hsp 70 ◽  
Mrna Accumulation ◽  
Mrna Induction ◽  
Xenopus Laevis Embryos

Elevation of the incubation temperature of Xenopus laevis neurulae from 22 to 33–35 °C induced the accumulation of heat shock protein (hsp) 70 mRNA (2.7 kilobases (kb)) and a putative hsp 87 mRNA (3.2 kb). While constitutive levels of both hsp mRNAs were detectable in unfertilized eggs and cleavage-stage embryos, heat-induced accumulation was not observed until after the mid-blastula stage. Exposure of Xenopus laevis embryos to other stressors, such as sodium arsenite or ethanol, also induced a developmental stage-dependent accumulation of hsp 70 mRNA. To characterize the effect of temperature on hsp 70 mRNA induction, neurulae were exposed to a range of temperatures (27–37 °C) for 1 h. Heat-induced hsp 70 mRNA accumulation was first detectable at 27 °C, with relatively greater levels at 30–35 °C and lower levels at 37 °C. A more complex effect of temperature on hsp 70 mRNA accumulation was observed in a series of time course experiments. While continuous exposure of neurulae to heat shock (27–35 °C) induced a transient accumulation of hsp 70 mRNA, the temporal pattern of hsp 70 mRNA accumulation was temperature dependent. Exposure of embryos to 33–35 °C induced maximum relative levels of hsp 70 mRNA within 1–1.5 h, while at 30 and 27 °C peak hsp 70 mRNA accumulation occurred at 3 and 12 h, respectively. Finally, placement of Xenopus neurulae at 22 °C after a 1-h heat shock at 33 °C produced an initial decrease in hsp 70 mRNA within 15–30 min, followed by a transient increase in hsp 70 mRNA at 1–2 h before decaying to background levels by 7 h.

Influence of stock density on digestive enzyme activity (trypsin), heat shock protein 70 (HSP70), and oxidative stress biomarkers of narrow clawed crayfish, Astacus leptodactylus Eschscholtz, 1823 (Decapoda, Astacidae)

Crustaceana ◽  
2016 ◽  
Vol 89 (10) ◽  
pp. 1193-1202 ◽  
Author(s):  
Ö. Aksu ◽  
F. Kutluyer ◽  
E. Can ◽  
M. Eri̇şi̇r ◽  
F. Benzer
Keyword(s):  
Oxidative Stress ◽  
Enzyme Activity ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Heat Shock Protein 70 ◽  
Digestive Enzyme ◽  
Stocking Density ◽  
Astacus Leptodactylus ◽  
Oxidative Stress Biomarkers ◽  
Stress Biomarkers

Stocking density causes changes in behaviour and physiology of aquatic animals and high density can cause oxidative damage in living cells. Therefore, experiments were designed to investigate the effects of stocking density on the oxidant-antioxidant response (glutathione (GSH), glutathione peroxidase (GSH-Px), catalase (CAT), and malondialdehyde (MDA)), digestive enzyme activity (trypsin), and heat shock protein 70 (HSP70) of narrow clawed crayfish (Astacus leptodactylus). The experiment was conducted to assess effects by stocking 3, 6, 9 and 12 crayfish/m2. Crayfish were stocked into 12 fiberglass tanks, three replicates per treatment and fed for 45 days. Our results indicated that activity of GSH-Px, MDA, and GSH levels increased in hepatopancreas () and muscle tissues () with increasing stock concentration while CAT activity decreased (). Trypsin and HSP70 insignificantly increased in haemolymph. In conclusion, oxidative stress biomarkers were negatively influenced by increased quantitative changes in stocking density.

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