Effect of heat shock on protein synthesis in flax rust uredosporelings

1985 ◽  
Vol 63 (11) ◽  
pp. 2069-2076 ◽  
Author(s):  
Maichael Shaw ◽  
Rosalinda Boasson ◽  
Leroy Scrubb

In uredosporelings of Melampsora lini (Ehrenb.) Lév. germinated for 3 h, uptake of [35S]methionine and its incorporation into protein were depressed during a 2-h heat shock induced by transfer from 17 ± 0.5 to 31 °C. Spectrophotometric scans of fluorograms, prepared after one-dimensional sodium dodecyl sulphate – polyacrylamide gel electrophoresis of aliquots of protein extracts containing equal numbers of disintegrations per minute (1 dps = 1 Bq) in protein, showed that heat shock induced statistically significant changes in the relative degrees of incorporation of [35S]methionine into 15 polypeptide bands. Increased labelling occurred in seven bands, which appear to be heat shock proteins with apparent molecular masses of 84, 71, 43.5, 30.5, 19.5, 18, and 17 kD. Decreased labelling occurred in eight bands, which appear to be heat stroke proteins with apparent molecular masses of 56, 54, 48, 46, 34, 32, 31.5, and 14 kD. When [35S]methionine was administered during heat shock at 31 °C the same pattern of polypeptide labelling was observed in extracts made immediately without return to 17 °C and in extracts made after uredosporelings were returned to 17 °C for 24 h. Thus label incorporated into each polypeptide during heat shock was retained for at least 24 h after the return to 17 °C. Administration of [35S]methionine at 17 °C after completion of the heat shock showed that the "normal" or "nonshock" pattern of labelling began to be resumed within 2 h after transfer from 31 to 17 °C. The results are discussed in relation to the effect of heat shock in promoting the initiation and growth of mycelial colonies from uredosporelings in axenic culture.

2008 ◽  
Vol 71 (11) ◽  
pp. 2289-2294 ◽  
Author(s):  
MING-LUN CHIANG ◽  
WEI-LI HO ◽  
ROCH-CHUI YU ◽  
CHENG-CHUN CHOU

Cells of Vibrio parahaemolyticus 690 were subjected either to heat shock at 42°C for 45 min or to ethanol shock in the presence of 5% ethanol for 60 min. The protein profiles of the unstressed and stressed V. parahaemolyticus cells were compared. Additionally, the induction of DnaK- and GroEL-like proteins in the unstressed and stressed cells of V. parahaemolyticus was also examined. Analysis with one-dimensional sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) indicated that three proteins with molecular masses of 93, 77, and 58 kDa were induced by both heat shock and ethanol shock. The protein patterns revealed by two-dimensional electrophoresis were more detailed than those revealed by one-dimensional SDS-PAGE. It was found that heat shock and ethanol shock affected the expression of a total of 28 proteins. Among them, four proteins with molecular masses of 94, 32.1, 26.7, and 25.7 kDa were enhanced by both heat shock and ethanol shock. Furthermore, immunoblot analysis showed the presence of a GroEL-like protein with a molecular mass of 61 kDa in the test organism, with the heat-shocked and ethanol-shocked cells producing a GroEL-like protein in a larger quantity than the unstressed cells. However, DnaK-like protein was not detectable in either the unstressed or the stressed cells.


1990 ◽  
Vol 68 (3) ◽  
pp. 609-615 ◽  
Author(s):  
J. R. Halle ◽  
S. Ghosh ◽  
E. B. Dumbroff ◽  
J. J. Heikkila

Leaf segments of Brassica napus were exposed to 22, 35, 38, or 40 °C for up to 4 h. Analysis of radiolabeled proteins by two-dimensional sodium dodecyl sulfate – polyacrylamide gel electrophoresis and fluorography revealed two major groups of heat shock proteins (HSPs). One group comprised HSPs 70, 76, and 87, with (pIs) isoelectric points ranging from 5.7 to 6.1, whereas the second group had molecular masses ranging from 23 to 16 kilodaltons (kDa) and pIs from 5.6 to 6.9. Immunoblot analysis using antibodies directed against the large (RLSU) and small (RSSU) subunits of ribulose-1,5-bisphosphate carboxylase (RUBISCO) showed that increasing temperatures from 35 to 38° or 40 °C for the duration of thermal stress (i.e., from 1 to 5 h) did not affect levels of the RSSU (15 kDa), whereas levels of the RLSU (52 kDa) fell sharply. Nevertheless, the activity of RUBISCO was not adversely affected at 38 °C for periods of up to 5 h. Northern blot analysis revealed that the increase observed in HSP 70 synthesis during heat shock may be transcriptionally regulated, but the decrease in the RLSU was not accompanied by a corresponding reduction in levels of its mRNA.Key words: Brassica, heat shock, ribulose-1,5-bisphosphate carboxylase, gene expression.


2021 ◽  
Vol 22 (5) ◽  
pp. 2591
Author(s):  
Pengfei Ma ◽  
Jie Li ◽  
Lei Qi ◽  
Xiuzhu Dong

Small heat shock proteins (sHsps) are widely distributed among various types of organisms and function in preventing the irreversible aggregation of thermal denaturing proteins. Here, we report that Hsp17.6 from Methanolobus psychrophilus exhibited protection of proteins from oxidation inactivation. The overexpression of Hsp17.6 in Escherichia coli markedly increased the stationary phase cell density and survivability in HClO and H2O2. Treatments with 0.2 mM HClO or 10 mM H2O2 reduced malate dehydrogenase (MDH) activity to 57% and 77%, whereas the addition of Hsp17.6 recovered the activity to 70–90% and 86–100%, respectively. A similar effect for superoxide dismutase oxidation was determined for Hsp17.6. Non-reducing sodium dodecyl sulfate polyacrylamide gel electrophoresis assays determined that the Hsp17.6 addition decreased H2O2-caused disulfide-linking protein contents and HClO-induced degradation of MDH; meanwhile, Hsp17.6 protein appeared to be oxidized with increased molecular weights. Mass spectrometry identified oxygen atoms introduced into the larger Hsp17.6 molecules, mainly at the aspartate and methionine residues. Substitution of some aspartate residues reduced Hsp17.6 in alleviating H2O2- and HClO-caused MDH inactivation and in enhancing the E. coli survivability in H2O2 and HClO, suggesting that the archaeal Hsp17.6 oxidation protection might depend on an “oxidant sink” effect, i.e., to consume the oxidants in environments via aspartate oxidation


1998 ◽  
Vol 64 (4) ◽  
pp. 1298-1302 ◽  
Author(s):  
Marguerite Dols ◽  
M. Remaud-Simeon ◽  
R. M. Willemot ◽  
M. Vignon ◽  
P. Monsan

ABSTRACT When grown in glucose or fructose medium in the absence of sucrose,Leuconostoc mesenteroides NRRL B-1299 produces two distinct extracellular dextransucrases named glucose glucosyltransferase (GGT) and fructose glucosyltransferase (FGT). The production level of GGT and FGT is 10 to 20 times lower than that of the extracellular dextransucrase sucrose glucosyltransferase (SGT) produced on sucrose medium (traditional culture conditions). GGT and FGT were concentrated by ultrafiltration before sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. Their molecular masses were 183 and 186 kDa, respectively, differing from the 195 kDa of SGT. The structural analysis of the dextran produced from sucrose and of the oligosaccharides synthesized by acceptor reaction in the presence of maltose showed that GGT and FGT are two different enzymes not previously described for this strain. The polymer synthesized by GGT contains 30% α(1→2) linkages, while FGT catalyzes the synthesis of a linear dextran only composed of α(1→6) linkages.


1981 ◽  
Author(s):  
K J Clemetson ◽  
J L McGregor ◽  
E James ◽  
M Dechavanne ◽  
E F Lüscher

It is well established that Bernard-Soulier syndrome (BSS) platelets are deficient in a major membrane glycoprotein (lb). In order to investigate if this is the only defect in this disorder and to see if the β-subunit of glycoprotein lb is also diminished, platelets from 3 BSS patients and from healthy donors were isolated, washed and surface labelled by lactoperoxidase-catalysed iodination, pèriodate/NaB3H4 or neuraminidase/ galactose oxidase/NaB3H4. Labelled platelets were solubilized in sodium dodecyl sulphate and separated by 2-dimensional gel electrophoresis (isoelectric focusing, discontinuous polyacrylamide gel electrophoresis). Glycoprotein Ibα was virtually absent in 2 patients and strongly decreased in the third patient. The 3-subunit was also absent in the 2 patients and present at about 40 % of normal in the third. Glycoprotein IIbβ was present normally in all patients. In addition, a further low molecular weight glycoprotein with a M.WT. of 17,000 and a pI of 6.8-7.5 was absent or present at levels paralleling glycoprotein Ibβ. The thrombin cleavable glycoprotein (GP IV or V) appeared greatly diminished with BSS platelets labelled by carbo-hydrate specific methods though no difference could be seen with iodination. This finding was confirmed in a fourth BSS patient using one dimensional gel electrophoresis.The defects in BSS platelets are thus more complex than previously thought.


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