Maize Allergens during seed development: transgenic versus non-transgenic

Recombinant DNA technology, also known as genetic engineering, allows the transfer of genes between unrelated species. As a result, a genetically modified organism (GMO) may contain one or more proteins coming from other organism/s. The application of genetic engineering to plants improvement and food production is becoming a common practice. New and diverse plant varieties have been obtained which are pest and disease resistant, more productive and with improved nutritional quality, flavour and shelf life. In spite of all these potential benefits, some apprehension persist regarding genetically modified organisms putative effects over human health and environment. One of the main concerns regards GMO’s potential allergenicity. One of the possibilities is that the introduction of a new/ altered gene may putatively alter the expression of others, namely endogenous allergens. In maize, there are already some proteins characterized as allergens, namely a lipid transport protein (Pastorello et al. 2000), a tioredoxin Zea m25 (Weichel et al. 2006), two glutelins Zea m27kD (Frisner et al. 2000) and 50kD Zein (Pasini et al. 2002) and one trypsin inhibitor (Pastorello et al. 2000). In this study, we have evaluated the expression of these 5 allergens, throughout MON 810 vs its non-transgenic counterpart seed development (10, 16 and 23 days after pollination). The expression profile of each one of these allergens varies during seed development, although the observed differences between Transgenic and Non-Transgenic maize were not statistical significant (t-test). Since there is a lack of experimental data regarding the correlation of allergen expression with food allergy clinical relevance, we are now comparing the immunologic response of maize allergic individuals against MON 810 maize vs its non transgenic control. We also intend to characterize the encountered potential maize allergens by mass spectrometry

Environmental stress is the major cause of transcriptomic and proteomic changes in GM and non-GM plants

The approval of genetically modified (GM) crops is preceded by years of intensive research to demonstrate safety to humans and environment. We recently showed that in vitro culture stress is the major factor influencing proteomic differences of GM vs. non-GM plants. This made us question the number of generations needed to erase such “memory”. We also wondered about the relevance of alterations promoted by transgenesis as compared to environment-induced ones. Here we followed three rice lines (1-control, 1-transgenic and 1-negative segregant) throughout eight generations after transgenesis combining proteomics and transcriptomics, and further analyzed their response to salinity stress on the F6 generation. Our results show that: (a) differences promoted during genetic modification are mainly short-term physiological changes, attenuating throughout generations, and (b) environmental stress may cause far more proteomic/transcriptomic alterations than transgenesis. Based on our data, we question what is really relevant in risk assessment design for GM food crops.This work was supported by Fundação para a Ciência e a Tecnologia (FCT) Project PTDC/EBB-BIO/098983/2008 and research unit GREEN-it “Bioresources for Sustainability” (UID/Multi/04551/2013). S.N. acknowledges funding from King Abdullah University of Science and Technology (KAUST).info:eu-repo/semantics/publishedVersio

Lettuce (Lactuca sativa L.) leaf-proteome profiles after exposure to cylindrospermopsin and a microcystin-LR/cylindrospermopsin mixture: A concentration-dependent response

The intensification of agricultural productivity is an important challenge worldwide. However, environmental stressors can provide challenges to this intensification. The progressive occurrence of the cyanotoxins cylindrospermopsin (CYN) and microcystin-LR (MC-LR) as a potential consequence of eutrophication and climate change is of increasing concern in the agricultural sector because it has been reported that these cyanotoxins exert harmful effects in crop plants. A proteomic-based approach has been shown to be a suitable tool for the detection and identification of the primary responses of organisms exposed to cyanotoxins. The aim of this study was to compare the leaf-proteome profiles of lettuce plants exposed to environmentally relevant concentrations of CYN and a MC-LR/CYN mixture. Lettuce plants were exposed to 1, 10, and 100 lg/l CYN and a MC-LR/CYN mixture for five days. The proteins of lettuce leaves were separated by twodimensional electrophoresis (2-DE), and those that were differentially abundant were then identified by matrix-assisted laser desorption/ionization time of flight-mass spectrometry (MALDI-TOF/TOF MS). The biological functions of the proteins that were most represented in both experiments were photosynthesis and carbon metabolism and stress/defense response. Proteins involved in protein synthesis and signal transduction were also highly observed in the MC-LR/CYN experiment. Although distinct protein abundance patterns were observed in both experiments, the effects appear to be concentration-dependent, and the effects of the mixture were clearly stronger than those of CYN alone. The obtained results highlight the putative tolerance of lettuce to CYN at concentrations up to 100 lg/l. Furthermore, the combination of CYN with MC-LR at low concentrations (1 lg/l) stimulated a significant increase in the fresh weight (fr. wt) of lettuce leaves and at the proteomic level resulted in the increase in abundance of a high number of proteins. In contrast, many proteins exhibited a decrease in abundance or were absent in the gels of the simultaneous exposure to 10 and 100 lg/l MC-LR/CYN. In the latter, also a significant decrease in the fr. wt of lettuce leaves was obtained. These findings provide important insights into the molecular mechanisms of the lettuce response to CYN and MC-LR/CYN and may contribute to the identification of potential protein markers of exposure and proteins that may confer tolerance to CYN and MC-LR/CYN. Furthermore, because lettuce is an important crop worldwide, this study may improve our understanding of the potential impact of these cyanotoxins on its quality traits (e.g., presence of allergenic proteins)

Biocontrol proteomics:Implication of the pentoses phosphates pathway in the antagonist effect of Pichia anomala against Botrytis cinerea on apple

The growing interest of the consumers for the wholesome food and the protection of the environment as well as the development of resistant pathogens to pesticides, stimulate the interest of growers to apply biological control methods. Pichia anomala strain K was previously identified as an efficient biocontrol agent of the main apple pathogens, Botrytis cinerea and Penicillum expansum. Further study demonstrated the complexicity of the mode of action of P. anomala against B. cinerea. A cDNA-AFLP and gene disruption study revealed implication of exo-β-1,3-glucanases in the mode of action of P. anomala strain Kh6 (a haploid form of P. anomala strain K displaying the same biocontrol properties). However, these studies suggested also implication of other factors. The present study aims to increase our knowledge of the mode of action of P. anomala strain Kh6 against B. cinerea using an in situ approach allowing the triple interaction, host/pathogen/antagonist and the proteomic tool allowing to study the ultime expression of the genome without a priori. One 50mm wound per apple were covered by a membrane and inoculated by a P. anomala suspension then by B. cinerea or not. Samples were collected during the exponential and stationary phase to identify the early and later responses to the presence of B. cinerea. After extraction, proteins were separated on 2-D gels. Spots influenced by the presence of B. cinerea in exponential and stationary phases were identified by MALDI-ToF. One hundred five and sixty spots of proteins were influenced by the presence of B. cinerea in exponential and stationary phases respectively. In exponential phase, P. anomala Kh6 in absence of B. cinerea uses mainly the glycolysis pathway, whereas in presence of pathogen, it orientates its energetic metabolism to the oxidative phosphorylation and sets up the pentose phosphate pathway. Thanks to this new orientation, P. anomala Kh6 probably obtains energy and nucleic acids allowing to colonize the wound as fast as in absence of B. cinerea and prevents the use of nutrients by the pathogen. In stationary phase, no differences in the P. anomala Kh6 energetic metabolism, in absence and in presence of B. cinerea were observed. During that phase, P. anomala Kh6 seems to use the alcoholic fermentation in order to face the nutrients impoverishment of the substrate

Maize IgE binding proteins: each plant a different profile?

Background: Allergies are nearly always triggered by protein molecules and the majority of individuals with documented immunologic reactions to foods exhibit IgE hypersensitivity reactions. In this study we aimed to understand if natural differences, at proteomic level, between maize populations, may induce different IgE binding proteins profiles among maize-allergic individuals. We also intended to deepen our knowledge on maize IgE binding proteins. Results: In order to accomplish this goal we have used proteomic tools (SDS-PAGE and 2-D gel electrophoresis followed by western blot) and tested plasma IgE reactivity from four maize-allergic individuals against four different protein fractions (albumins, globulins, glutelins and prolamins) of three different maize cultivars. We have observed that maize cultivars have different proteomes that result in different IgE binding proteins profiles when tested against plasma from maize-allergic individuals. We could identify 19 different maize IgE binding proteins, 11 of which were unknown to date. Moreover, we found that most (89.5%) of the 19 identified potential maize allergens could be related to plant stress. Conclusions: These results lead us to conclude that, within each species, plant allergenic potential varies with genotype. Moreover, considering the stress-related IgE binding proteins identified, we hypothesise that the environment, particularly stress conditions, may alter IgE binding protein profiles of plant components

Toxin Induction and Protein Extraction from Fusariumspp. Cultures for Proteomic Studies

Fusaria are filamentous fungi able to produce different toxins. Fusarium mycotoxins such as deoxynivalenol, nivalenol, T2, zearelenone, fusaric acid, moniliformin, etc... have adverse effects on both human and animal health and some are considered as pathogenicity factors. Proteomic studies showed to be effective for deciphering toxin production mechanisms (Taylor et al., 2008) as well as for identifying potential pathogenic factors (Paper et al., 2007, Houterman et al., 2007) in Fusaria. It becomes therefore fundamental to establish reliable methods for comparing between proteomic studies in order to rely on true differences found in protein expression among experiments, strains and laboratories. The procedure that will be described should contribute to an increased level of standardization of proteomic procedures by two ways. The filmed protocol is used to increase the level of details that can be described precisely. Moreover, the availability of standardized procedures to process biological replicates should guarantee a higher robustness of data, taking into account also the human factor within the technical reproducibility of the extraction procedure

Proteomic changes in rat hippocampus and adrenals following short-term sleep deprivation

ABSTRACT: BACKGROUND: To identify the biochemical changes induced by sleep deprivation at a proteomic level, we compared the hippocampal proteome of rats either after 4 hours of sleep or sleep deprivation obtained by gentle handling. Because sleep deprivation might induce some stress, we also analyzed proteomic changes in rat adrenals in the same conditions. After sleep deprivation, proteins from both tissues were extracted and subjected to 2D-DIGE analysis followed by protein identification through mass spectrometry and database search. RESULTS: In the hippocampus, 87 spots showed significant variation between sleep and sleep deprivation, with more proteins showing higher abundance in the latter case. Of these, 16 proteins were present in sufficient amount for a sequencing attempt and among the 12 identified proteins, inferred affected cellular functions include cell metabolism, energy pathways, transport and vesicle trafficking, cytoskeleton and protein processing. Although we did not observe classical, macroscopic effect of stress in sleep-deprived rats, 47 protein spots showed significant variation in adrenal tissue between sleep and sleep deprivation, with more proteins showing higher abundance following sleep. Of these, 16 proteins were also present in sufficient amount for a sequencing attempt and among the 13 identified proteins, the most relevant cellular function that was affected was cell metabolism. CONCLUSION: At a proteomic level, short term sleep deprivation is characterized by a higher expression of some proteins in the hippocampus and a lower abundance of other proteins in the adrenals (compared to normal sleep control). Altogether, this could indicate a general activation of a number of cellular mechanisms involved in the maintenance of wakefulness and in increased energy expenditure during sleep deprivation. These findings are relevant to suggested functions of sleep like energy repletion and the restoration of molecular stocks or a more global homeostasis of synaptic processes

Selection of the best comparator for the risk assessment of GM plants- conventional counterpart vs. negative segregant

Abstract for 12th international Symposium on biosafety of genetically modified organisms The identification of similarities and differences between GM plants and derived food/feed and their comparators plays a central role in risk assessment strategy. Therefore, selecting the right comparators must be one of the top priorities. The question is which control would allow us to better evaluate the potential unintended effects related directly to the transgene and/or DNA rearrangements, discounting the potential effects caused by in vitro culture procedures; since, these are non-controversial procedures also used in conventional breeding. Aiming to answer the previous question we have used Multiplex fluorescence 2D gel electrophoresis technology (DyeAGNOSTICS Refraction-2D) coupled with MS to characterize the proteome of three different rice lines (Oriza sativa L. ssp. Japonica cv Nipponbare): A control conventional counterpart. An Agrobacterium transformed transgenic line. A negative segregant (homozygous negative progeny) from a different transgenic line. We have observed that transgenic and negative segregant plant lines grouped together (only 1 differentially regulated spot - fold difference > 1.5, ANOVA, P1.5, ANOVA, P<0.05, in both transgenic and negative segregant lines comparing to control line). Additionally, the 35 proteins identified (using MS) in this study, were already associated with stress response by other authors. The only feature in common between the transgenic and negative segregant lines is that they have both suffered in vitro culture procedures. Hence, the results obtained indicate that, in this study, different gene disruption and/or DNA rearrangements and the presence/absence of transgene were factors with less impact on rice proteome than the proteomic promoted differences caused by in vitro culture, and eventually the stress caused by this process. This work highlights the importance of continuous revision and upgrade of the guidance criteria to be followed for the selection of suitable comparators in GMO risk assessment

An in‑planta comparative study of Plasmopara viticola proteome reveals diferent infection strategies towards susceptible and Rpv3‑mediated resistance hosts

Plasmopara viticola, an obligate biotrophic oomycete, is the causal agent of one of the most harmful grapevine diseases, downy mildew. Within this pathosystem, much information is gathered on the host, as characterization of pathogenicity and infection strategy of a biotrophic pathogen is quite challenging. Molecular insights into P. viticola development and pathogenicity are just beginning to be uncovered, mainly by transcriptomic studies. Plasmopara viticola proteome and secretome were only predicted based on transcriptome data. In this study, we have identified the in-planta proteome of P. viticola during infection of a susceptible ('Trincadeira') and a Rpv3-mediated resistance ('Regent') grapevine cultivar. Four hundred and twenty P. viticola proteins were identified on a label-free mass spectrometry-based approach of the apoplastic fluid of grapevine leaves. Overall, our study suggests that, in the compatible interaction, P. viticola manipulates salicylic-acid pathway and isoprenoid biosynthesis to enhance plant colonization. Furthermore, during the incompatible interaction, development-associated proteins increased while oxidoreductases protect P. viticola from ROS-associated plant defence mechanism. Up to our knowledge this is the first in-planta proteome characterization of this biotrophic pathogen, thus this study will open new insights into our understanding of this pathogen colonization strategy of both susceptible and Rpv3-mediated resistance grapevine genotypes.info:eu-repo/semantics/publishedVersio