Effect of arsenic-phosphorus interaction on arsenic-induced oxidative stress in chickpea plants

Arsenic-induced oxidative stress in chickpea was investigated under glasshouse conditions in response to application of arsenic and phosphorus. Three levels of arsenic (0, 30 and 60 mg kg−1) and four levels of P (50, 100, 200, and 400 mg kg−1) were applied to soil-grown plants. Increasing levels of both arsenic and P significantly increased arsenic concentrations in the plants. Shoot growth was reduced with increased arsenic supply regardless of applied P levels. Applied arsenic induced oxidative stress in the plants, and the concentrations of H2O2 and lipid peroxidation were increased. Activity of superoxide dismutase (SOD) and concentrations of non-enzymatic antioxidants decreased in these plants, but activities of catalase (CAT) and ascorbate peroxidase (APX) were significantly increased under arsenic phytotoxicity. Increased supply of P decreased activities of CAT and APX, and decreased concentrations of non-enzymatic antioxidants, but the high-P plants had lowered lipid peroxidation. It can be concluded that P increased uptake of arsenic from the soil, probably by making it more available, but although plant growth was inhibited by arsenic the P may have partially protected the membranes from arsenic-induced oxidative stress

Identification of QTLs for Arsenic Accumulation in Maize (Zea mays L.) Using a RIL Population

The Arsenic (As) concentration in different tissues of maize was analyzed using a set of RIL populations derived from an elite hybrid, Nongda108. The results showed that the trend of As concentration in the four measured tissues was leaves>stems>bracts>kernels. Eleven QTLs for As concentration were detected in the four tissues. Three QTLs for As concentration in leaves were mapped on chromosomes 1, 5, and 8, respectively. For As concentration in the bracts, two QTLs were identified, with 9.61% and 10.03% phenotypic variance. For As concentration in the stems, three QTLs were detected with 8.24%, 14.86%, and 15.23% phenotypic variance. Three QTLs were identified for kernels on chromosomes 3, 5, and 7, respectively, with 10.73%, 8.52%, and 9.10% phenotypic variance. Only one common chromosomal region between SSR marker bnlg1811 and umc1243 was detected for QTLs qLAV1 and qSAC1. The results implied that the As accumulation in different tissues in maize was controlled by different molecular mechanism. The study demonstrated that maize could be a useful plant for phytoremediation of As-contaminated paddy soil, and the QTLs will be useful for selecting inbred lines and hybrids with low As concentration in their kernels

The deuteron: structure and form factors

A brief review of the history of the discovery of the deuteron in provided. The current status of both experiment and theory for the elastic electron scattering is then presented.Comment: 80 pages, 33 figures, submited to Advances in Nuclear Physic

Differential pain response at local and remote muscle sites following aerobic cycling exercise at mild and moderate intensity

Physical exercise has been shown to inhibit experimental pain response in the post-exercise period. Modulation of the pain system may be differentiated between muscle sites engaging in contractile activity. The purpose of this study was to assess the pain response at remote and local muscle sites following aerobic exercise at different work intensities. Participants included 10 healthy and physically active males (mean age ± SD, 21.2 ± 3.4). Somatic pressure pain threshold (PPT) at the rectus femoris (local) and brachioradialis (remote) muscle site was measured at before (Pre), 5 min after (Post1), and 15 min after (Post2) aerobic cycling exercise at 70 and 30 % of peak oxygen uptake (VO(2peak)) performed on different occasions in a counterbalanced order, separated by minimum of 3 days interval. Repeated measures ANOVA for PPT reveals significant main effect for time (f = 3.581, p = 0.049, observed power = 0.588) and muscle site (f = 17.931, p = 0.002, observed power = 0.963). There was a significant interaction shown for exercise intensity by time (f = 11.390, p = 0.012, observed power = 0.790). PPT at rectus femoris following cycling exercise at 70 % of VO(2peak) reveals a significant increase between Pre-Post1 (p = 0.040). PPT for rectus femoris following cycling exercise at 30 % of VO(2peak) revealed a significant decrease between Pre-Post1 (p = 0.026) and Pre-Post2 (p = 0.008). The PPT for brachioradialis following cycling exercise at 30 % of VO(2peak) revealed a significant decrease between Pre-Post1 (p = 0.011) and Pre-Post2 (p = 0.005). These results show that aerobic exercise increases PPT locally at the exercise muscle site following exercise at 70 % of VO(2peak) but reduces PPT following exercise at 30 % of VO(2peak)

Long-term postharvest aroma evolution of tomatoes with the alcobaça (alc) mutation

The postharvest evolution of Penjar tomatoes has been studied in four accessions representative of the variability of the varietal type. The long-term shelf life of these materials, which carry the alc allele, was confirmed with 31.2-59.1% of commercial fruits after 6 months of effective conservation at room temperature and a limited loss of weight (21.1-27.9%). Aroma in Penjar tomatoes is differentiated from other tomato varieties by a characteristic 'sharp-floral' aroma descriptor. The evolution of the 'sharp-floral' aroma during postharvest showed a peak of intensity at 2 months of postharvest, though in one accession a delay of 2 months in this response was detected. Out of 25 volatiles analysed, including main and background notes, a reverse iPLS variable selection revealed that the main candidates behind this aromatic behaviour are ¿-terpineol, trans-2-hexenal, 6-methyl-5-hepten-2-one, trans-2-octenal, ¿-pinene, ß-ionone, 2 + 3-methylbutanol and phenylacetaldehyde. Between harvest and 2 months postharvest, most compounds reduced considerably their concentration, while the intensity of the 'sharp-floral' descriptor increased, which means that probably there is a rearrangement of the relative concentrations among volatiles that may lead to masking/unmasking processes. © 2011 Springer-Verlag.This work was supported by grants from the Conselleria de Agricultura, Pesca y Alimentacio de la Comunidad Valenciana, the Fundacion de la Comunidad Valenciana para la Investigacion Agroalimentaria (AGROALIMED) and from the Departament d'Agricultura, Alimentacio i Accio Rural (DAR) de la Generalitat de Catalunya.Casals Missio, J.; Cebolla Cornejo, J.; Rosello Ripolles, S.; Beltran Arandes, J.; Casanas, F.; Nuez Viñals, F. (2011). Long-term postharvest aroma evolution of tomatoes with the alcobaça (alc) mutation. European Food Research and Technology. 233(2):331-342. doi:10.1007/s00217-011-1517-6S3313422332Petro-Turza M (1987) Flavor of tomato and tomato products. Food Rev Int 2:309–351Butterry RG (1993) Quantitative and sensory aspects of flavor of tomato and other vegetables and fruits. In: Acree TE, Teranishi R (eds) Flavor science: sensible principles and techniques. American Chemical Society, WashingtonGoff SA, Klee HJ (2006) Plant volatile compounds: sensory cues for health and nutritional value? Science 311:815–819Tieman DM, Zeigler M, Schmelz EA, Taylor MG, Bliss P, Kirst M, Klee MJ (2006) Identification of loci affecting flavour volatile emissions in tomato fruits. J Exp Bot 57:887–896Zanor MI, Rambla JL, Chaïb J, Steppa A, Medina A, Granell A, Fernie AR, Causse M (2009) Metabolic characterization of loci affecting sensory attributes allows an assessment of the influence of the levels of primary metabolites and volatile organic contents. J Exp Bot 60:2139–2154Ortiz-Serrano P, Gil JV (2010) Quantitative comparison of free and bound volatiles of two commercial tomato cultivars (Solanum lycopersicum L.) during ripening. J Agric Food Chem 58:1106–1114Boukobza F, Taylor AJ (2002) Effect of postharvest treatment on flavour volatiles of tomatoes. Postharvest Biol Technol 25:321–331Vrebalov J, Ruezinsky D, Padmanabhan V, White R, Medrano D, Drake R, Schuch W, Giovannoni J (2002) A MADS-box gene necessary for fruit ripening at the tomato ripening-inhibitor (rin) locus. Science 296:343–346Giovannoni JJ, Tanksley SD, Vrebalov J, Noensie E (2004) NOR gene for use in manipulation of fruit quality and ethylene response. US Patent No 5,234,834 issued 13 July 2004McGlasson WB, Last JH, Shaw KJ, Meldrum SK (1987) Influence of the non-ripening mutants rin and nor on the aroma of tomato fruit. HortScience 22:632–634Baldwin EA, Scott JW, Shewmaker CK, Schuch W (2000) Flavor trivia and tomato aroma: biochemistry and possible mechanisms for control of important aroma components. HortScience 35:1013–1022Kovács K, Rupert CF, Tikunov Y, Graham N, Bradley G, Seymour GB, Bovy AG, Grierson D (2009) Effect of pleiotropic ripening mutations on flavour volatile biosynthesis. Phytochemistry 70:1003–1008Gao HY, Zhu BZ, Zhu HL, Zhang YL, Xie YH, Li YC, Luo YB (2007) Effect of suppression of ethylene biosynthesis on flavour products in tomato fruits. Russ J Plant Physiol 54:80–88Lewinsohn E, Sitrit Y, Bar E, Azulay Y, Meir A, Zamir D, Tadmor Y (2005) Carotenoid pigmentation affects the volatile composition of tomato and watermelon fruits, as revealed by comparative genetic analyses. J Agric Food Chem 53:3142–3148Kopeliovitch E, Mizrahi Y, Rabinowitch D, Kedar N (1980) Physiology of the mutant alcobaca. Physiol Plant 48:307–311Casals J, Pacual L, Cañizares J, Cebolla-Cornejo J, Casañas F, Nuez F (2011) Genetic basis of long shelf life and variability into Penjar tomato. Genet Resour Crop Evol. doi: 10.1007/s10722-011-9677-6Kuzyomenskii AV (2007) Effect of cumulative polymery of tomato keeping life genes. Cytol Genet 41:268–275Paran I, van der Knaap E (2007) Genetic and molecular regulation of fruit and plant domestication traits in tomato and pepper. J Exp Bot 58:3841–3852Moretti CL, Baldwin EA, Sargent SA, Huber DJ (2002) Internal bruising alters aroma volatile profiles in tomato fruit tisúes. HortScience 37:378–382Buttery RG, Teranishi R, Ling LC (1987) Fresh tomato aroma volatiles: a qualitative study. J Agric Food Chem 35:540–544Romero del Castillo R, Valero J, Casañas F, Costell E (2008) Training validation and maintenance of a panel to evaluate the texture of dry beans (Phaseolus vulgaris L.). J Sens Stud 23:303–319Beltran J, Serrano E, López FJ, Peruga A, Valcárcel M, Roselló S (2006) Comparison of two quantitative GC-MS methods for analysis of tomato aroma based on purge-and-trap and on solid-phase microextraction. Anal Bioanal Chem 385:1255–1264Martens H, Naes T (1989) Multivariate Calibration. Wiley, New YorkWise BM, Gallagher NB, Bro R, Shaver JM, Windig W, Koch RS (2006) Chemometrics tutorial for PLS_Toolbox and Solo. Eigenvector Research, WenatcheeHongsoongnern P, Chambers E (2008) A lexicon for texture and flavor characteristics of fresh and processed tomatoes. J Sens Stud 23:583–599Norgaard L, Saudland A, Wagner J, Nielsen JP, Munck L, Engelsen SB (2000) Interval partial least-squares regression (iPLS): A comparative chemometric study with an example from near-infrared spectroscopy. Appl Spectrosc 54:413–419Javanmardi J, Kubota C (2006) Variation of lycopene, antioxidant activity, total soluble solids and weight loss of tomato during postharvest storage. Postharvest Biol Technol 41:151–155Kader AA (1986) Effects of postharvest handling procedures on tomato quality. Acta Hort 190:209–222Maul F, Sargent SA, Sims CA, Baldwin EA, Balaban MO, Huber DJ (2000) Tomato flavor and aroma quality as affected by storage temperature. J Food Sci 65:1228–1237Krumbein A, Auerswald H (1998) Characterization of aroma volatiles in tomatoes by sensory analyses. Nahrung 6:S395–S399Tandon KS, Baldwin EA, Shewfelt RL (2000) Aroma perception of individual volatile compounds in fresh tomatoes (Lycopersicon esculentum Mill.) as affected by the medium of evaluation. Postharvest Biol Technol 20:261–268Cebolla-Cornejo J, Roselló S, Valcárcel M, Serrano E, Beltran J, Nuez F (2011) Evaluation of genotype and environment effects on taste and aroma flavour components of Spanish fresh tomato varieties. J Agric Food Chem 59:2440–2450Carbonell-Barrachina AA, Agustí A, Ruiz JJ (2006) Analysis of flavor volatile compounds by dynamic headspace in traditional and hybrid cultivars of Spanish tomatoes. Eur Food Res Technol 222:536–542Alonso A, Vázquez-Araújo L, García-Martínez S, Ruiz JJ, Carbonell Barrachina AA (2009) Volatile compounds of traditional and virus-resistant breeding lines of Muchamiel tomatoes. Eur Food Res Technol 230:315–323Liggett E, Drake MA, Delwiche JF (2008) Impact of flavor attributes on consumer liking of Swiss cheese. J Dairy Sci 91:466–476Ortiz-Serrano P, Gil JV (2007) Quantitation of free and glycosidically bound volatiles in and effect of glycosidase addition on three tomato varieties (Solanum lycopersicum L.). J Agric Food Chem 55:9170–9176Xu Y, Barringer S (2010) Comparison of tomatillo and tomato volatile compounds in the headspace by selected ion flow tube mass spectrometry (SIFT-MS). J Food Sci 75:C268–C273Berna AZ, Lammertyn J, Saevels S, Di Natale C, Nicolai BM (2004) Electronic nose systems to study shelf life and cultivar effect on tomato aroma profile. Sens Actuators B Chem 97:324–333Baldwin EA, Scott JW, Einstein MA, Malundo TMM, Carr BT, Shewfelt RL, Tandon KS (1998) Relationship between sensory and instrumental analysis for tomato flavor. J Am Soc Hortic Sci 12:906–915Krumbein A, Peters P, Brückner B (2004) Flavour compounds and a quantitative descriptive analysis of tomatoes (Lycopersicon esculentum Mill.) of different cultivars in short-term storage. Postharvest Biol Technol 32:15–2

Prediction of Cellular Burden with Host--Circuit Models

Heterologous gene expression draws resources from host cells. These resources include vital components to sustain growth and replication, and the resulting cellular burden is a widely recognised bottleneck in the design of robust circuits. In this tutorial we discuss the use of computational models that integrate gene circuits and the physiology of host cells. Through various use cases, we illustrate the power of host-circuit models to predict the impact of design parameters on both burden and circuit functionality. Our approach relies on a new generation of computational models for microbial growth that can flexibly accommodate resource bottlenecks encountered in gene circuit design. Adoption of this modelling paradigm can facilitate fast and robust design cycles in synthetic biology

Characterization and mitigation of gene expression burden in mammalian cells

Despite recent advances in circuit engineering, the design of genetic networks in mammalian cells is still painstakingly slow and fraught with inexplicable failures. Here, we demonstrate that transiently expressed genes in mammalian cells compete for limited transcriptional and translational resources. This competition results in the coupling of otherwise independent exogenous and endogenous genes, creating a divergence between intended and actual function. Guided by a resource-aware mathematical model, we identify and engineer natural and synthetic miRNA-based incoherent feedforward loop (iFFL) circuits that mitigate gene expression burden. The implementation of these circuits features the use of endogenous miRNAs as elementary components of the engineered iFFL device, a versatile hybrid design that allows burden mitigation to be achieved across different cell-lines with minimal resource requirements. This study establishes the foundations for context-aware prediction and improvement of in vivo synthetic circuit performance, paving the way towards more rational synthetic construct design in mammalian cells