Authors:Katalin Jámbrik, C. Máthé, G. Vasas, I. Bácsi, G. Surányi, S. Gonda, G. Borbély, and Márta M.-Hamvas
The toxic effects of cylindrospermopsin (cyanobacterial toxin) on animals have been examined extensively, but little research has focused on their effects on plants. In this study cylindrospermopsin (CYN) caused alterations of growth, soluble protein content and protease enzyme activity were studied on two aquatic plants Lemna minor and Wolffia arrhiza in short-term (5 days) experiments. For the treatments we used CYN containing crude extracts of Aphanizomenon ovalisporum (BGSD-423) and purified CYN as well. The maximal inhibitory effects on fresh weight of L. minor and W. arrhiza caused by crude extract were 60% and 54%, respectively, while the maximum inhibitory effects were 30% and 43% in the case of purified CYN at 20 μg ml−1 CYN content of culture medium. In CYN-treated plants the concentration of soluble protein showed mild increases, especially in W. arrhiza. Protease isoenzyme activity gels showed significant alterations of enzyme activities under the influence of CYN. Several isoenzymes were far more active and new ones appeared in CYN-treated plants. Treatments with cyanobacterial crude extract caused stronger effects than the purified cyanobacterial toxins used in equivalent CYN concentrations.
The germination and water uptake of Vicia faba seeds were suppressed in response to the treatments with the different concentrations of sea water (5%, 25% and 50%). The following parameters were increased: the osmotic potential, Na+, Cl, proline and protease activity. While K+, K+/Na+ ratio, Ca2+, amylase activity and total soluble sugars were decreased. Gibberellic acid treatments to the seeds counteracted the harmful effect which were induced by sea water treatments. In turn the germination percentage, water uptake, K+, K+/Na+ ratio, Ca2+, total soluble sugars, a-amylase and protease activities were increased, while Na+, Cl, and proline were decreased. The changes in protein banding pattern in Vicia faba germinated seeds in sea water were investigated. Salinization induced de novo synthesis of some salt responsive proteins. The salt responsive proteins might be osmotin (M wt 23.39 and 26.86 KDa), dehydrin (36.79 and 40.63 KDa) and ubiquitin (8.81 KDa) which were apparent in Vicia faba seeds. The seeds priming soaking in GA and germinated in sea water induced de novo synthesis of some responsive proteins. This indicated that gibberellic acid had a synergistic effect on the induction of the salt gene which is responsible for the synthesis of the mentioned proteins.
Grain Protein Content (GPC) of wheat is significant for enhanced nutritional value and is one of the most important aspects effecting pasta and bread making quality as well. Seventy seven Pakistani wheat varieties and advance lines were analysed to access the allelic distribution at microsatellite Xuhw89 locus using functional SSR marker. Overall, 42% of tested wheat genotypes were found to carry 126 + 130-bp allele while a 126-bp allele was detected in 58% of genotypes. A target band of 126-bp was amplified in all tested genotypes, however, an additional band of 130-bp was also detected along with 126-bp band in 32 genotypes. Genotypes i.e. (Punjab-96) total soluble protein and (MEXI PAK) globulin with 126 + 130-bp allele while (Faisalabad-2008) salt soluble protein and (TC-4928) albumin with allele of 126-bp depicted highest grain protein content. The alleles identification associated with maximum grain protein content in Pakistani wheat germplasm will assist in accelerating the breeding program in future.
Authors:A. Sattar, M.A. Cheema, A. Sher, T. Abbas, M. Ijaz, S. Ul-Allah, M. Butt, A. Qayyum, and M. Hussain
The impact of trinexapac-ethyl (TE) on salinity subjected wheat plants was evaluated via pot based experiment. The treatments applied to wheat seedlings included (Ck) control (no NaCl nor TE spray), foliar spray of TE (1.95 ml L−1), only NaCl (50 mM) and NaCl+ TE (50 mM + 1.95 ml L−1). Foliar application of TE was done seven days after imposition of salinity. Growth parameters (root length, shoot length, fresh weight, and dry weight) and photosynthetic pigments content (chlorophyll a, b, a + b and a/b), water relation (water potential, osmotic potential, turgor potential and relative water contents) as well as catalase (CAT) activity exhibited marked reduction in comparison to control. In addition, an increment was noted in organic solutes content (proline, soluble protein and soluble sugar) and enzyme activity of superoxide dismutase (SOD), peroxidase (POD), and ascorbate peroxidase (APX) in stressed seedlings over control seedlings. The foliar applied TE mostly enhanced growth of salt stressed seedlings, accompanied by reinforcement in photosynthetic pigments, organic solutes, and enzyme activity (SOD, CAT, POD, and APX) in comparison to stressed seedlings. It is worthy to mention that, TE has potential to enhance salt tolerance of wheat seedlings. Thus, our findings suggest that seedling treated with TE is an effective strategy that can be used to enhance salt tolerance of wheat crop.
Drought is one of most important environmental factors inhibiting photosynthesis and decreasing growth and productivity of plants. The sensitivity of crop plants such as wheat to soil drought is particularly serious during reproductive phase is extremely sensitive to plant water status. The aim of this work was to study the effects of drought stress on photosynthesis, photosynthetic pigments, soluble proteins, a-tocopherol and abscisic acid content in six wheat genotypes, two tolerant (Daric and 92 Zhong), two moderately tolerant (Sabalan and DH-2049-3) and two sensitive (Shark and Tevee’s’). Total chlorophyll content, relative water content and chlorophyll a/b ratio decreased after long-time drought stress, that decrease in sensitive genotypes was higher than others. Net photosynthesis and stomatal conductance decreased significantly (P < 0.05) in flag leaves of our genotypes under drought stress after pollination, that decrease in sensitive genotypes was higher, too. Abscisic acid content, soluble protein content and a-tocopherol increased under drought stress, that increase in tolerant genotypes was higher. There was a significant negative correlation (P < 0.05) between photosynthesis factors and abscisic acid content in flag leaves of all genotypes. It can be concluded that Daric and 92 Zhong had a better photosynthesis factors compared to other genotypes and showed a higher capacity to tolerate drought stress.
Authors:Roghieh Hajiboland, Sara Bahrami-Rad, and Soodabeh Bastani
Modification in the metabolism of phenolic compounds under boron (B) deficiency conditions was studied in tea plants. Plants were grown from seed, treated with low B in hydroponic medium under environmentally controlled conditions for six weeks. Dry matter production and B content of plants were significantly declined under B deficiency conditions. Boron starvation resulted in rising phenylalanine ammonia lyase activity in the young leaves and declining polyphenol oxidase activity in the roots. Soluble phenolics fraction was increased up to 3.4-fold in the young leaves while did not influence by B nutrition in the old leaves and roots. Cell wall (CW) bound phenolics and lignin content was lower in B-deficient plants compared with B-sufficient ones. Boron deficiency increased significantly activity of soluble peroxidase (POD) only in the leaves. Activity of ionically bound POD was decreased in the old leaf and roots while it increased in the young leaves upon B deprivation. Activity of covalently bound POD decreased in the roots and leaves of different age in low B plants. Our results suggested that tea plant is highly tolerant species to B deficiency and CW tightening and accumulation of oxidized phenolics are not mechanisms for growth inhibition under B deficiency conditions.
The effects of diuron, a photosystem II inhibiting herbicide, on lipid peroxidation, photosynthetic pigments, soluble protein, proline contents and some antioxidant enzymes in maize leaves were studied and protective effects of polyamines against diuron toxicity were investigated. Diuron significantly increased lipid peroxidation, suggesting oxidative damage in the plants and proline content, while it decreased total chlorophyll, carotenoid and soluble protein levels in the leaves during the experiments. Pretreatment with polyamines statistically decreased lipid peroxidation induced by diuron and spermine (SPM) proved to be the most effective polyamine. Also, pretreatment with polyamines significantly prevented the losses of total chlorophyll, carotenoid and soluble protein induced by diuron. On the other hand, pretreatment with polyamines significantly increased proline contents of the leaves in comparison with the leaves treated with diuron. Superoxide dismutase (SOD), guaiacol peroxidase (GPX) and glutathione reductase (GR) activities increased in the leaves treated with diuron while catalase (CAT ) activity decreased. Pretreatment with spermidine (SPD) did not change significantly SOD activity at 24 and 72 hrs of diuron treatment but prevented the increase in SOD activity induced by diuron at 48 h. However, pretreatment with SPD increased GPX activity at 24 h and GR activity at 48 and 72 hrs. CAT activity in the leaves pretreated with SPD was similar to that of the leaves treated with diuron. Pretreatment with SPM prevented the increase in SOD activity induced by diuron at 48 h but significantly increased it at 72 h of diuron treatment. However, pretreatment with SPM did not significantly change GPX and GR activities during the experiments but reversed the decrease in CAT activity induced by diuron at 72 h. Pretreatment with putrescine (PUT) prevented the increase in SOD activity induced by diuron at 48 and 72 hrs while it increased GPX and GR activities at 48 h of diuron treatment. Also, the decrease in CAT activity induced by diuron at 72 h was completely prevented by PUT. It can be concluded that pretreatment of maize leaves with polyamines reduced the damage produced by diuron and the protective effects of polyamines against diuron toxicity were closely associated with antioxidant system.
Authors:S. Hu, H. Shu, J.L. Yuan, J.Y. Gao, P.Y. Mu, C.Z. Ren, W. Sang, L.C. Guo, and H.B. Chen
-accepted quality ( Wani & Kumar, 2016 ) and improved antioxidant activity ( Smarma et al., 2012 ). Among whole grains, oat has well-recognised health beneﬁts. The Food and Drug Administration conﬁrmed that soluble ﬁbres (β-glucan) from oats can reduce low
Authors:Dóra Rédei, Norbert Kúsz, Máté Szabó, Gyula Pinke, István Zupkó, and Judit Hohmann
The present work is the first phytochemical investigation of Euphorbia davidii Subils. After multistep separation process, three flavonoid glycosides were obtained from the ethyl acetate soluble fraction of the methanol extract of the whole plant. The structures of the isolated compounds were determined as kaempferol 3-O-rhamnoside, myricetin 3-O-rhamnoside, and quercetin 3-O-rhamnoside. Aqueous and organic extracts of the plant were screened in vitro for antiproliferative activity against HeLa (cervix epithelial adenocarcinoma), A431 (skin epidermoid carcinoma), A2780 (ovarian carcinoma) and MCF7 (breast epithelial adenocarcinoma) cells, using the MTT assay. n-Hexane and chloroform extracts demonstrated moderately dose-dependent cell growth inhibitory activity against all four cell lines.
Authors:J. Kerrigan, C. Ragunath, Lili Kandra, GYöngyi Gyémánt, A. Lipták, L. Jánossy, J. Kaplan, and N. Ramasubbu
Bacteria in a biofilm are enmeshed in a self-synthesized extracellular polysaccharide matrix (PGA), which is a linear polymer of β(1,6)-linked N-acetylglucosamine (GlcNAc) residues. Dispersin B (DspB), a soluble glycoside hydrolase produced by the periodontal pathogen
degrades PGA. The enzyme DspB is an α/β TIM-barrel protein and belongs to family 20 glycosyl hydrolases members. The enzyme activity of DspB with regard to its substrate specificity towards β(1,6)-linked GlcNAc polymers and its endo/exo character was investigated through ligand docking and the hydrolysis of synthetic oligosaccharides. Ligand docking analysis suggested that β(1,6)-linked GlcNAc oligosaccharide bound to the active site better that β(1,4)-linked GlcNAc oligosaccharide. Our combined results indicate that DspB is an exo-acting enzyme that hydrolyzes β(1,6)-linked N-acetylglucosamine oligomers.