Proteomic analysis of Spirogyra varians mutant with high starch content and growth rate induced by gamma irradiation

Gamma irradiation protect the developing wheat endosperm from oxidative damage by balancing the trade-off between the defence network and grains quality

Gamma irradiation has been reported to modulate the biochemical and molecular parameters associated with the tolerance of plant species under biotic/ abiotic stress. Wheat is highly sensitive to heat stress (HS), as evident from the decrease in the quantity and quality of the total grains. Here, we studied the effect of pre-treatment of wheat dry seeds with different doses of gamma irradiation (0.20, 0.25 and 0.30 kGy) on tolerance level and quality of developing wheat endospermic tissue under HS (38 °C, 1 h; continuously for three days). Expression analysis of genes associated with defence and starch metabolism in developing grains showed maximum transcripts of HSP17 (in response to 0.25 kGy + HS) and AGPase (under 0.30 kGy), as compared to control. Gamma irradiation was observed to balance the accumulation of H₂O₂ by enhancing the activities of SOD and GPx in both the cvs. under HS. Gamma irradiation was observed to stabilize the synthesis of starch and amylose by regulating the activities of AGPase, SSS and α-amylase under HS. The appearance of isoforms of gliadins (α, β, γ, ω) were observed more in gamma irradiated seeds (0.20 kGy), as compared to control. Gamma irradiation (0.25 kGy in HD3118 & 0.20 kGy in HD3086) was observed to have positive effect on the width, length and test seed weight of the grains under HS. The information generated in present investigation provides easy, cheap and user-friendly technology to mitigate the effect of terminal HS on the grain-development process of wheat along with development of robust seeds with high nutrient density.

Proteomic studies on anti-tumor agent ansamitocin P-3 producer Actinosynnema pretiosum in response to ammonium and isobutanol

Our previous work showed that the biosynthesis of ansamitocin P-3 (AP-3), an anti-tumor agent, by Actinosynnema pretiosum was depressed by ammonium but enhanced by isobutanol in the medium. Here we show proteomics analyses on A. pretiosum in different fermentation conditions with and without ammonium or isobutanol using two-dimensional electrophoresis (2-DE), matrix-assisted laser desorption/ionization, and linear ion trap quadrupole mass spectrometry. Pairwise comparison of repetitive 2-DE maps was performed to find differentially expressed spots, and eight proteins were identified as functionally annotated ones. Among these proteins, D-3-phosphoglycerate dehydrogenase (PGDH) and glyceraldehyde 3-phosphate dehydrogenase showed statistically significant up-regulation in ammonium vs. basic or isobutanol medium, while fatty acid synthetase, histidine-tRNA ligase, transposase, molecular chaperone GroEL, SAM-dependent methyltransferase, and Crp/Fnr family transcriptional regulator were overexpressed in ammonium vs. basic medium. Based on the 2-DE data, exogenous L-serine which could inhibit the PGDH activity was added to the cultures with isobutanol, and a lower AP-3 production was confirmed under 2.5 mM serine addition (24 or 48 h).

Enhancing the growth rate and astaxanthin yield of Haematococcus pluvialis by nuclear irradiation and high concentration of carbon dioxide stress

Unicellular green microalgae Haematococcus pluvialis was mutated with (60)Co-γ irradiation to promote growth rate and increase astaxanthin yield under high concentration of CO2 stress. The average specific growth rate of H. pluvialis mutated with 4000 Gy γ-ray irradiation was increased by 15% compared with the original strain with air aeration. The mutant grew best with 6% CO2 (the maximum specific growth rate was 0.60/d) when it was cultured with high concentrations of CO2 (2-10%). The peak biomass productivity (0.16 g/L/d) of the mutant cultured with 6% CO2 was 82% higher than that of the mutant with air. The astaxanthin yield and lipid content of the mutant induced with 6% CO2 and high light (108 μmol photons m(-2) s(-1)) increased to 46.0mg/L and 45.9%, which were 2.4 and 1.3 times higher than those of the wild-type strain, respectively.