Authors:X.L. Jiang, G.F. Chen, X.J. Li, G. Li, Z.G. Ru and J.C. Tian
This study aimed to clarify the genetic mechanisms behind wheat flour color. Flour colorrelated traits (L*, a*, and b*) and polyphenol oxidase (PPO) activity are important parameters that influence the end-use quality of wheat. Dissecting the genetic bases and exploring important chromosomal loci of these traits are extremely important for improving wheat quality. The diverse panel of 205 elite wheat varieties (lines) was genotyped using a highdensity Illumina iSelect 90K single-nucleotide polymorphisms (SNPs) assay to disclose the genetic mechanism of flour color-related traits and PPO activity. In 2 different environments and their mean values (MV), 28, 30, 24, and 12 marker-trait associations (MTAs) were identified for L*, a*, b* traits, and PPO activity, respectively. A single locus could explain from 5.52% to 20.01% of the phenotypic variation for all analyzed traits. Among them, 5 highly significant SNPs (P ≤ 0.0001), 11 stable SNPs (detected in all environments) and 25 multitrait MTAs were identified. Especially, BS00000020_51 showed pleiotropic effects on L*, a*, and b*, and was detected in all environments with the highest phenotypic contribution rates. Furthermore, this SNP was also found to be co-associated with wheat grain hardness, ash content, and pasting temperature of starch in previous studies. The identification of these significantly associated SNPs is helpful in revealing the genetic mechanisms of wheat colorrelated traits, and also provides a reference for follow-up molecular marker-assisted selection in wheat breeding.
Authors:A. Kamalakannan, L. Mohan, K. Kavitha, S. Harish, R. Radjacommare, S. Nakkeeran, V. K. Parthiban, R. Karuppiah and T. Angayarkanni
Five isolates of Trichoderma viride, Pseudomonas fluorescens and four isolates of Bacillus subtilis were evaluated for their ability to control Rhizoctonia solani, the causal agent of stem and stolon rot of peppermint (Mentha piperita Lin.). Of the various isolates of T. viride, P. fluorescens and B. subtilis tested, TVUV10, PFMMP and BSG3 showed the maximum inhibition of mycelial growth of R. solani. Among these isolates, P. fluorescens, PFMMP recorded the highest inhibition zone against R. solani in vitro and was very effective in reducing disease incidence in greenhouse condition. The effective isolates were evaluated for their ability to induce defense related enzymes and chemicals in plants. Increased activity of phenylalanine ammonia lyase (PAL), peroxidase (PO), polyphenoloxidase (PPO) and total phenolics were recorded in the biocontrol agents pretreated peppermint plants challenged with R. solani. P. fluorescens isolate PFMMP recorded early and increased synthesis of all defense related enzymes and total phenol. Thus, the present study shows that application of biocontrol agents; induce defense related enzymes involved in phenyl propanoid pathway in addition to direct antagonism which collectively contribute for enhanced resistance against invasion of R. solani in M. piperita.
Authors:Y. Gautam, A. Sharma, S. Sharma, K. Rao, J. Kumar, V. Kumar, B. Singh, A. Kumar and A. Hedge
Atmospheric tritium activity is measured regularly around Narora Atomic Power Station (NAPS) since gaseous waste, which contains
tritium, is being released through a 145 m high stack at NAPS site. Atmospheric data collected during 2004–2008 shows a large
variation of 3H concentration in air, fluctuating in the range of ≤0.2–91.6 Bq m−3. Significantly, higher tritium levels were measured in samples near the site boundary (1.6 km) of NAPS compared to off-site
locations. The atmospheric dilution factor was found to be in the range of 1.1 × 10−7–7.3 × 10−7 s m−3. The scavenging ratio of NAPS site was found to be varying from 0.2 × 104 to 14.1 × 104 (Bq m−3 rain water per Bq m−3 air). The inhalation dose to a member of general public at different distances (1.6–30 km) from NAPS site was found to be
ranged from 0.08–0.21 μSv year−1.
The phenolic profile and specific activity of oxidative enzymes in sorghum leaves and stem resistant and susceptible to
(Swinhoe) were analyzed at 45 and 60 days after germination. Resistant varieties had higher content of total phenols, o-dihydric phenols, flavanols and tannins than the susceptible varieties at both the stages of plant growth and the concentration of these biomolecules increased after infestation as well as with plant age in both sets of varieties. Moreover, resistant varieties exhibited higher specific activity of polyphenol oxidase, peroxidase, phenylalanine ammonia-lyase and tyrosine ammonia-lyase in their leaves and stem in comparison to the corresponding activities in susceptible ones. Peroxidase activity was several folds than the polyphenol oxidase. Healthy leaves of susceptible varieties showed higher catalase activity in comparison with resistant ones at day 45 and this trend was reversed at day 60. Role of phenolic compounds and oxidative enzymes particularly the peroxidase in determining resistance against stem borer has been high lighted.
Authors:Irina Petreanu, Daniela Ebrasu, Claudia Sisu and Mihai Varlam
and aromatic hydrocarbon polymers; (3) using inorganic–organic composites; (4) membranes based on acid–base polymers [ 1 ].
Poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) is an engineering plastic, thermally and chemically stable, that could be
Authors:G.P. Li, D. Zhou, L.N. Kan, Y.W. Wu, J.F. Fan and J. Ouyang
The inhibitory effects of phytic acid (PA) on the browning of fresh-cut chestnuts and the associated mechanisms of PA on polyphenol oxidase (PPO) and peroxidase (POD) activities were investigated. The enzymatic browning of chestnut surfaces and interiors was suppressed by soaking shelled and sliced chestnuts in a PA solution. The specific activities of PPO and POD extracted from chestnuts declined due to inhibition by PA. PA was determined to be a competitive inhibitor of both PPO and POD by Lineweaver-Burk plots. The binding modes of PA with PPO and POD were analysed by AutoDock 4.2.
Authors:I. Szedljak, K. Szántai-Kőhegyi, M. Tóth and B. Bernhardt
Millet has attracted a great deal of interest due to its valuable agricultural, nutritional, and functional properties. In this study the aim was the investigation of millet usability in dry pasta products. Chemical, enzymological, and sensory parameters were measured and monitored in Triticum aestivum, Triticum durum, and millet containing pasta products during a 12-month-long storage period. According to our results, during the storage, millet had a strong effect on different parameters: because of increased acid value, the shelf life was reduced, and millet significantly influenced the pH value and the water soluble polyphenol content. The highest scores were measured in T. durum and T. durum-millet pasta samples in the sensory test, while the T. aestivum-millet mixture pasta got the lowest scores. Also in our experiment we tested how the drying temperature modifies polyphenol oxidase enzyme (PPO) activity right after drying and during storage. The samples containing millet flour had higher PPO activity in all cases after drying, while pasta made with T. durum had the lowest PPO activity. Our results showed that drying temperature has a significant impact on PPO activity.
Slow evaporation of toluene from poly(2,6-dimethyl-1,4-phenylene oxide), PPO, at 23°C produced crystals which melt between 185 and 265°C and have a crystallinityof 0.58. About 8 wt% of the crystals appear to melt temperatures below 220°C. The lattertemperature marks the end of the glass transition interval for this polymer.
Authors:Zoltán Mayer, Nguyen Hong Duc, Zita Sasvári and Katalin Posta
The association between terrestrial plants and arbuscular mycorrhizal (AM) fungi is one of the most common and widespread mutualistic plant-fungi interaction. AM fungi are of beneficial effects on the water and nutrient uptake of plants and increase plant defense mechanisms to alleviate different stresses. The aim of this study was to determine the level of polyphenol oxidase (PPO), guaiacol peroxidase (POX) and glutathione S-transferase (GST) enzyme activities and to track the expression of glutathione S-transferase (GST) gene in plant-arbuscular mycorrhizal system under temperature- and mechanical stress conditions. Our results suggest that induced tolerance of mycorrhizal sunflower to high temperature may be attributed to the induction of GST, POX and PPO enzyme activities as well as to the elevated expression of GST. However, the degree of tolerance of the plant is significantly influenced by the age which is probably justified by the energy considerations.
Authors:R. Avtar, A. S. Rathi, D. S. Jatasra and U. N. Joshi
The contents of total phenols and orthodihydric phenols, specific activities of polyphenol oxidase (PPO), peroxidase (PO) and catalase in leaves of powdery mildew resistant (NLM and HM 350) and susceptible (T 8 and HM 65) genotypes of fenugreek were estimated at 40, 80 and 100 days after sowing (DAS) in inoculated (E1) and natural (E2) environments. The levels of all the biochemical constituents were higher in resistant genotypes than in susceptible ones before the appearance of disease (40 DAS) in both the environments. In response to infection, an increase was observed in contents of all the parameters except catalase activity in all the genotypes. However, at higher disease severity levels of all the biochemical parameters decreased invariably in all the genotypes except activities of PPO and PO which increased further in susceptible genotypes in both the environments. The role of phenolics and oxidative enzymes in determining resistance in fenugreek against powdery mildew disease has been highlighted.