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The chain of events that leads to the sensitization of the immune system to environmental antigens, resulting in the onset of allergic disease, has been studied in great detail over the past 30 years. However, during this time, the rate of allergic diseases has increased exponentially, indicating the need to concentrate our studies on host-environmental factors that contribute to the onset of disease. Monocyte-derived dendritic cells (DCs) play a key role in driving localized and systemic immune responses. In this study, we developed a platform for screening the molecular signature and phenotypic profile of DCs activated by allergenic stimuli, including TSLP, IL-25, IL-33, IL-1a, Vit-D3 (1α,25-Dihydroxyvitamin D3), PAR1-AP Peptide, Papain, and recombinant human DerP1 protein to induce a type II associated inflammatory signature. Following activation with allergenic stimuli, modulated DCs are subjected to deep phenotyping via flow cytometry for surface and intracellular markers to detect and/or validate immunomodulatory properties. RNA sequencing is further used to compare the gene expression profiles of DCs responding to either allergenic or microbial stimuli, including the TLR3 agonist dsRNA Poly I:C and TLR4 agonist LPS. In our study, we aimed to identify key molecular signatures of DCs involved in the development of asthma and allergy based on their comparative activation with this broad panel of allergens. We expect to determine central control modules of transcription factors in DCs associated with Th2 induction.

The soybean cyst nematode (SCN),Heterodera glycines, is a widespread pest in most soybean-producing areas, causing serious damage to soybean crops and resulting in economic losses. We have previously reported that bean sprout residue might function as an environmentally-friendly control agent against SCN. In order to understand the role of water extracted from bean sprout residue as a possible factor in lowering the number of SCN, either water extract of bean sprout residue (WE) or water (W) was applied to pots containing soil infested with SCN, and komatsuna plants, a leafy vegetable, were grown in these pots. After 2 months, the number of SCN, estimated with real-time PCR, was 80% lower in WE than in W and the biomass of komatsuna plants was 100% higher in WE than in W, suggesting that WE has not only an SCN eradication effect but also a fertilisation effect. In field experiments, WE or W was applied ten times during the experimental period from July 2010 to June 2011. The number of SCN decreased by 82% in WE and by 36% in W; however, the marked decrease was observed only between July and September and between April and June. Green soybean plants were grown in the field where WE or W had been applied and the yield was markedly higher in WE (750 g m−2) than in W (200 g m−2). The hatching stimulation of SCN eggs by WE was tested at four different temperatures (10, 20, 25, 30°C) and was observed only at 25°C. These results show that water extract of bean sprout residue decreases the density of SCN and thereby damage to green soybeans, and that the suppressive effect depends on soil temperature.

Food industry tends towards the use of controlled microorganisms in order to improve its technologies including frozen starter production. The fungus Geotrichum candidum, which is currently found in various environments, is widely used as ripening agent in some specific cheese making process. In order to optimize the cryopreservation of this microorganism, freezing experiments were carried out using a Peltier cooler-heater incubator, which permits to control the temperature downshift from +20 to -10 degrees C in time period ranges from 20 to 40min depending on the experiments. Concomitantly, study of the effect of an industrial ice nucleator protein derived from Pseudomonas syringae (SNOMAX) on the dynamic of freezing of G. candidum was carried out. Our results showed that the addition of this protein in the microbiological suspension has different complementary effects: (i) the synchronization of the different samples nucleation, leading to an homogeneous and earlier freezing, (ii) the increase of the freezing point temperature from -8.6 to -2.6 degrees C, (iii) a significant decrease of the lethality of G. candidum cells subjected to a freezing-thawing cycles challenge.

International audience; Geotrichum candidum is a micro-fungus widely used as a ripening starter in cheese making. In anthropogenic environments such as dairy industries, this microorganism is subjected to many environmental and technological stresses including low temperature exposure. Our aim was to study the proteomic response of G. candidum to cold stress using a comparative proteomic approach by two-dimensional Differential In Gel Electrophoresis (2D DIGE). This technique consists on the labeling of proteins by specific fluorescent dyes (CyDyes). The results, obtained with G. candidum cells subjected to cold temperature, show significant proteomic patterns differences compared with the standard conditions. Furthermore, this biochemical response seems strain specific. 2D DIGE technology combined with SameSpots™ software analysis support these results through an important statistical validity. The comparative studies in a single gel, using two different fluorescent CyDyes (Cy3 and Cy5), lead to proteins differentiation. Selected spots were treated and analyzed by mass spectrometry.

Any modification of the environment that leads to a physiological, genetic, or epigenetic adaptive response in microorganisms may be considered as a stress. Historically, forms of stresses affecting biological structures were classified either as non-thermal, such as osmotic, oxidative, or acid stress or as thermal stress, hot or cold. Currently, the classification in biology is as abiotic, including physical and chemical stress, or biotic. The aim of this mini-review is to show, through the example of microorganisms, that the response to stress can be considered, in biology, as a global phenomenon, which can be extended to anthropogenic pressure.