Physio-biochemical Responses of In Vitro Cooking Banana Musa paradisiaca cv Lang towards Pseudo Induced Drought Stress by Polyethylene Glycol (PEG)

Musa paradisiaca cv Lang belongs to cooking banana group, and it has high potential to be used in banana chips production. Like other cultivars, M. paradisiaca cv Lang is susceptible towards water shortage, therefore affecting banana growth and productivity. In this study, to mimic the drought condition, pseudo-drought stress was given to in vitro Lang banana seedlings by adding polyethylene glycol (PEG). Overall, decrement of roots length and chlorophyll (Chl) content was displayed by the seedlings exposed to 1%, 2%, 3%, 4%, and 5% (w/v) of PEG after three weeks of exposure. The proline content, total soluble protein content, and antioxidant capacity in leaf and roots, however, countered differently towards different levels of drought. Proline content showed the highest in leaf of 2% (w/v) PEG-treated seedling (12.66±0.38 µmoles/g) while the total soluble protein content showed the highest in roots of 5% (w/v) of PEG-treated seedling (30.65±1.07 mg/g FW). Antioxidant capacity of stressed seedlings revealed the catalase (CAT), guaiacol peroxidase (POD), and ascorbate peroxidase (APX) activities were the highest in the leaf of 1% (w/v) (10.69±5.06 µmol/min/mg), 4% (w/v), (0.079±0.03 µmol/min/mg), and 5% (w/v) (9.11±8.47 µmol/min/mg) of PEG- treated seedlings, respectively. Meanwhile, the highest CAT, POD, and APX activities in the roots were determined in 3% (w/v) (0.49±0.04 µmol/min/mg), 2% (w/v) (0.03±0.02 µmol/min/mg), and 3% (w/v) (16.69±0.5 µmol/min/mg) of PEG-treated seedlings, respectively. These data show that PEG can be a priming agent to induce defense system at seedling stage of banana, which could enhance their survivability during ex vitro acclimatization.

Effect of selenium enriched wheat substrate on the nutritional and antioxidant properties of Pleurotus spp.

The study demonstrated that cultivation of Pleurotus ostreatus var. florida, Pleurotus eryngii, Pleurotus cornucopiae and Pleurotus djamor on selenium enriched substrate did not significantly affect biological efficiency (%), but total soluble protein content, total phenolic content, flavonoid content and free radical scavenging activity (%) were found to be significantly improved in Se enriched fruit bodies as compared to the control. Elemental analysis of the Se biofortified Pleurotus mushrooms through SEM-EDS showed signals characteristic for selenium on surface of P. ostreatus. var. florida and P. djamor confirming that selenium was incorporated into the cell wall of these fruiting bodies. The Se content was found to be 22.34 μg g−1 dw in Se enriched wheat straw and 0.059 μg g−1 dw in respective non-enriched wheat straw. Se contents of Se-enriched fruit bodies were found to be higher compared to non-enriched Pleurotus spp. FT-IR spectra of proteins from Pleurotus spp. indicated an increase in the flexibility, unfolding, hydrophilicity of the proteins upon Se supplementation.

Protein pattern of canola (Brassica napus L.) changes in response to salt and salicylic acid in vitro

The effect of salicylic acid (SA) on the salt (NaCl) tolerance mechanism was studied in canola plants (oilseed rape, Brassica napus L.) by molecular and physiological experiments in plant tissue culture. Seeds of B. napus ‘Ocapy’ were germinated at 0, 50, and 100 mM NaCl on Murashige and Skoog (MS) medium containing different levels (0, 2, and 5 μM) of SA for 4 weeks. Total chlorophyll, carotenoid, and flavonoid content increased in response to interactive effects of SA and NaCl treatments at some concentrations. Proline content was increased under salt and SA treatments in shoot and root tissues. Salt alone and in combination with SA increased the total soluble protein content of shoots only, while the different concentrations of SA in the culture media affected variously the total soluble protein content. Protein patterns of shoots and roots showed some remarkable differences, based on gel electrophoresis and the consequent analysis of bands by ImageJ program. The relative expression of 15 and 12 protein bands in shoots and roots, respectively, differed under the applied treatments. In addition, the protein profile indicated that salinity and SA regulate the expression of salt-stress-inducible proteins as well as induced de novo synthesis of specific polypeptides. The findings may help to explain the salt tolerance mechanisms and to produce salt-tolerant canola plants.

Salt Stress and Homobrassinosteroid Interactions during Germination in Barley Roots

Potential alleviation effects of Homobrassinosteroid (HBR) (0.5 and 1 µM HBR) on root germination, cell division and antioxidant system enzymes (superoxide dismutase and catalase) of barley (Hordeum vulgare L. cv. ‘Hilal’) roots grown under different salt concentrations (150 mM and 250 mM) were investigated during 48 and 72 h at dark with their controls. Salt applications decreased primary root lengths, seminal root lengths, number of roots from one seed, mitotic activity and induced mitotic abnormalities. In addition, salt application decreased protein content but increased enzyme activities both at 48 h and 72 h when compared to control. Roots treated with HBR enhanced root lengths and root number. HBR-treated roots showed more mitotic activity, mitotic abnormalities and significant enlargements at the root tips when compared to controls and only salt-treated samples. Salt + HBR applications stimulated root lengths and showed more mitotic activity and mitotic abnormalities when compared to only salt-treated samples. Salt application increased superoxide dismutase and catalase activities both at 48 h and 72 h. However, HBR application decreased total soluble protein content and increased enzyme activities especially at 48 h compared to control. Depending on concentration and timing, salt + HBR treatments showed varying results in total soluble protein content and enzyme activities. There was also a significant change in protein banding patterns of experimental groups separated by SDS-PAGE. These findings are expected to contribute to understanding of how HBR affect barley roots grown under different salt concentrations.

ZnO/SnO2/Montmorillonite Composite for Inhibition of Cyanobacterial Bloom

ZnO/SnO2/montmorillonite that could flocculate and restrict the growth of Microcystis aeruginosa used as a probe of cyanobacterial was prepared and characterized by means of XRD and TEM. In ZnO/SnO2/montmorillonite, ZnO and SnO2nanoparticles disperse on montmorillonite surface. The determinations of chlorophyll a levels and total soluble protein content demonstrate that ZnO/SnO2/montmorillonite has stronger flocculation effect on Microcystis aeruginosa compared with natural montmorillonit under visible light, and has a good photocatalytic degradation effect on Microcystis aeruginosa under UV irradiation. Under UV, 96.79% removal efficiency is achieved for Microcystis aeruginosa in 1h using 50mg.L-1ZnO/SnO2/montmorillonite. The synergy of absorption flocculation and photocatalysis of ZnO/SnO2/montmorillonite promotes the removal of Microcystis aeruginosa.

Changes of Araucaria araucana seed reserves during germination and early seedling growth

Changes in the starch and protein reserves of Araucaria araucana (Mol.) Koch embryo and megagametophyte tissue during the first 90 h after the start of imbibition have been measured by colorimetric and by chromatographic methods. The starch content (about 30%) of the embryo decreases rapidly until radicle protrusion–germination (40 h) and remains relatively constant (at about 9%) after that. Starch content of the megagametophyte decreases slowly throughout the 90 h. Amylase activity and soluble carbohydrate content of the embryo peak rapidly at 20 h, decline rapidly until germination, and increase slowly thereafter. Total amylase activity of the megagametophyte does not change markedly. Total soluble-protein content of the embryo decreases during the first 20 h and increases thereafter. The embryo protein bodies also disappear during the first 20 h. The hypocotyl enlarges to a bulbous shape and may serve as a secondary protected reserve.

Biochemical changes in cultured foetal rat liver explants

Liver explants from 20-day-old foetuses cultured for 48h in the absence of serum released 70% of their total soluble protein content into the medium. In the presence of serum this loss still amounted to 60%. The concentration of total particulate protein remained unchanged but there was some translocation of mitochondrial enzymes to the cytosol, and enzymes expected to increase during this stage of development failed to do so. The addition of cortisol plus glucagon (to serum-containing media) did not decrease the loss of total soluble protein from the explants but induced considerable tyrosine aminotransferase activity which was not released into the medium. The observations suggest that under the usual culture conditions a minority of the cells retain their functional integrity. The extent of deterioration, not reflected in histologically visible necrosis or cell damage, can be conveniently monitored by the malate dehydrogenase activity released to the medium.

Antioxidant activity in Brassica napus L. plants expressing lox-dependent BAR gene

Aim. The study of possible unintended biochemical peculiarities of newly obtained herbicide-resistant canola (Brassica napus L.) plants expressing the lox-dependent BAR gene was the aim. Methods. Total soluble protein content, total free radical scavenging activity, and superoxide dismutase activity have been investigated using Bradford’s, DPPH, and nitroblue tetrazolium assays, respectively. Fresh weight of plants grown on media with or without phosphinothricin was also measured. Results. The antioxidant activity of leaf extracts of untransformed plants under in vitro growth condi-tions had no significant differences in comparison with ones of phospinothricin-resistant plants in the third generation. No significant changes in parameters investigated were observed in transgenic plants cultivated on media with herbicide addition compared to ones grown on media without it. Fresh weight and total soluble protein content were similar in transgenic and untransformed canola plants under growth without phosphinothricin. Conclusions. Lox-dependent BAR gene introduction and expression resulted in no significant differences in leaf antioxidant activity in transgenic canola plants comparing to untransformed controls.Keywords: Brassica napus, antioxidant activity, DPPH, glufosinate, superoxide dismutase.