Search results for " microbial"

Pyrosequencing vs. culture-dependent approaches to analyze lactic acid bacteria associated to chicha, a traditional maize-based fermented beverage fr…

2015

The diversity of lactic acid bacteria (LAB) associated with chicha, a traditional maize-based fermented alcoholicbeverage from Northwestern Argentina, was analyzed using culture-dependent and culture-independent approaches.Samples corresponding to 10 production steps were obtained from two local producers at Maimará(chicha M) and Tumbaya (chicha T). Whereas by culture-dependent approach a few number of species(Lactobacillus plantarum and Weissella viridescens in chicha M, and Enterococcus faecium and Leuconostocmesenteroides in chicha T) were identified, a higher quantitative distribution of taxa was found in both beveragesby pyrosequencing. The relative abundance of OTUs was higher in chic…

Fermentative stress adaptation of hybrids within the Saccharomyces sensu stricto complex.

2008

Along the fermentation process yeasts are affected by a succession of stress conditions that affect their viability and fermentation efficiency. Among the stress conditions the most relevant are high sugar concentration and low pH in musts, temperature and, as fermentation progresses, ethanol accumulation. Nowadays, due to the demanding nature of modern winemaking practices and sophisticated wine markets, there is an ever-growing search for particular wine yeast strains possessing a wide range of optimized, improved or novel enological characteristics. Traditionally, the species S. cerevisiae and S. bayanus within the Saccharomyces sensu stricto species are considered some of the most impor…

Ultraviolet B Irradiation Affects Resistance of Rainbow Trout (Oncorhynchus mykiss) Against Bacterium Yersinia ruckeri and Trematode Diplostomum spat…

2007

Ultraviolet B (UVB) radiation is known to have various effects on the immune system of fish, but the effect on the actual disease resistance has remained largely unknown. Here we studied the effect of UVB on the resistance of rainbow trout (Oncorhynchus mykiss) against a bacterium Yersinia ruckeri, the causative agent of enteric red mouth disease, and a trematode parasite Diplostomum spathaceum, which causes cataracts in fish. The fish were exposed to UVB irradiation seven times in 14 days, and inoculated intraperitoneally with Y. ruckeri on day 5 after the first irradiation. On day 2 postinfection (p.i.), the number of viable bacteria in the kidney was lower in UVB-exposed than in unexpose…

Comparative efficacy of Zataria multiflora Boiss., Origanum compactum and Eugenia caryophyllus essential oils against E. coli O157:H7, feline caliciv…

2013

Abstract Ready-to-eat salads using baby-leaf and multi-leaf mixes are one of the most promising developments in the fresh-cut food industry. There is great interest in developing novel decontamination treatments, which are both safe for consumers and more efficient against foodborne pathogens. In this study, emulsions of essential oils (EOs) from Origanum compactum (oregano), Eugenia caryophyllus (clove), and Zataria multiflora Boiss (zataria) were applied by spray (0.8 ml) after the sanitizing washing step. The aim was to investigate their ability to control the growth of potentially cross-contaminating pathogens and endogenous microbiota in commercial baby leaves, processed in a fresh-cut…

A spatially explicit model to simulate soil microbial communities’ dynamics at an agricultural landscape scale

2021

Soil microorganisms play a major role in soil functions and are an efficient indicator to evaluate the impact of agricultural practices on soil quality. Biogeographical studies over wide scales ranging from landscape to countries have concluded that soil microbial abundance and soil prokaryotic richness is following a heterogeneous distribution in space under the dependence of soil properties (e.g. pH, soil texture, organic matter content) and agricultural practices. The goal of this study is the creation of a model that can predict dynamics of soil microbial communities depending on the agricultural management over time. For this, we focus on a monitored landscape (Fénay landscape, 1.200 h…

A new tool to assess the ecotoxicological impact of β-triketone herbicides on soil microbial communities

2018

International audience; The β-triketone herbicides are post-emergence maize selective herbicides that have beenintroduced on the market, in replacement of atrazine, banned in Europe in 2004. Qualified as “eco-friendly”, since they are based on natural phytotoxin properties, these herbicides target an enzymeinvolved in carotenoid biosynthesis called 4-hydroxyphenylpyruvate dioxygenase (HPPD) encoded bythe hppd gene. The inhibition of this enzyme provokes bleaching symptoms, necrosis and death ofweeds.The hppd gene is not only find in eukaryotes such as plants, animals and humans but also inprokaryotes such as fungi, yeasts and bacteria. In recent studies, we showed that, within the soil bact…

Comparison of different tillage systems in organic farming : effect of soil structure and organic matter repartition on soil micro-organisms and thei…

2009

Over the last decades, the surface traditionally ploughed has tended to decrease and replaced by shallow working tillage techniques without soil inversion, i.e., no tillage or reduced tillage with tines or discs. These techniques were mostly developed in conventional farming systems but nowadays they are also developed in organic farming systems. Nevertheless, these tillage techniques could generate crop nutrients deficiencies and a deterioration of soil structure, especially during the first years of their application. As the use of synthetic fertilizers is forbidden in organic farming, a decrease of the soil fertility could be very detrimental for crop growth. Indeed, soil micro-organisms…

Innovative tools to diagnose the impact of land use practices on soil microbial communities

2018

International audience; Preservation and sustainable use of soil biological communities represent major challenges in the current agroecological context. Indeed, most of soil ecosystem services results from biological functions particularly driven by taxonomic and functional assemblages of microbiological communities (i.e. nutrient cycling, soil aggregation, depollution, etc.). Consequently, soil microbial communities are logical candidates as effective indicators of soil quality and sustainability. But, good biological indicators must be associated with references that encompass an operating range of measured values that allow performing the desired diagnosis. Even if numerous studies have…

Assemblage, structuration et évolution des communautés microbiennes terrestres

2020

Ecological role of mycotoxins produced by Fusarium graminearum : consequences of the presence of deoxynivalenol (DON) in crop residues on the soil mi…

2012

Fusarium graminearum is a plant pathogenic fungus, causing devastating disease “Fusarium head blight” (FHB) in cereals including wheat and maize. It also contaminates the grains with mycotoxins including deoxynivalenol (DON) which are toxic to human and animals. This disease has resulted in the serious losses in grain yield and quality. We established through a first bibliographic review that during off season fungus survives saprophytically on the crop residues (ecological habitat) and serves as primary inoculum for the next season crop. However, we noticed also that the literature was poor about the role mycotoxins could play in the establishment of F. graminearum in such a habitat. The m…