Search results for "Microbial"

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

Mapping, understanding and predicting soil microbial diversity across France

2018

International audience; Microorganisms are extremely abundant and diverse in soils. Their huge diversity is central in soil functioning regarding the diversity of functions it supports (mineralization, detoxification, stability of soil…) and is more and more studied, especially in a context of increasing pressure on soil resources. Conversely to macroorganisms whose distribution on a wide scale has been studied for over a century, spatial scaling and determinism distribution of soil microorganisms on nationwide scale still needs to be documented, notably to decipher the environmental filters shaping these communities. communities were investigated at the scale of France to characterize thei…

Étude multi-isotopique de microbialites actuels au sein d'analogues Précambriens (lacs de cratères volcaniques alcalins)

2021

Extraction of essential oil from Aloysia citriodora Palau leaves using continuous and pulsed ultrasound: Kinetics, antioxidant activity and antimicro…

2018

International audience; The impact of continuous and pulsed ultrasound pre-treatments (15, 30 and 45 min) followed by conventional hydrodistillation on the characteristics of extracted essential oils (EOs) from dried leaves of Aloysia citriodora Palau was evaluated for the first time. Chemical composition of EOs, antibacterial and antioxidant activities, as well as the contents in heavy metals (iron, copper, lead, arsenic, and cadmium) were determined. Pretreating the leaves with ultrasound (continuous and pulsed), before hydrodistillation, resulted in shorter extraction time (93.81–121.16 min) and higher extraction yields (2.8 (v/w) %) (p < 0.05), compared to the non-sonicated leaves (extr…

Osmotic stress affects the stability of freeze-dried Lactobacillus buchneri R1102 as a result of intracellular betaine accumulation and membrane char…

2014

Aims To help cells to better resist the stressful conditions associated with the freeze-drying process during starter production, we investigated the effect of various osmotic conditions on growth, survival and acidification activity of Lactobacillus buchneri R1102, after freeze-drying and during storage for 3 months at 25°C. Methods and Results High survival rates during freeze-drying, but not during storage, were obtained when 0·1 mol l−1 KCl was added at the beginning of fermentation, without any change in membrane properties and betaine accumulation. This condition made it possible to maintain a high acidification rate throughout the process. In contrast, the addition of 0·6 mol l−1 KCl…

Exploring the diversity of listeria monocytogenes biofilm architecture by high-throughput confocal laser scanning microscopy and the predominance of …

2015

ABSTRACT Listeria monocytogenes is involved in food-borne illness with a high mortality rate. The persistence of the pathogen along the food chain can be associated with its ability to form biofilms on inert surfaces. While most of the phenotypes associated with biofilms are related to their spatial organization, most published data comparing biofilm formation by L. monocytogenes isolates are based on the quantitative crystal violet assay, which does not give access to structural information. Using a high-throughput confocal-imaging approach, the aim of this work was to decipher the structural diversity of biofilms formed by 96 L. monocytogenes strains isolated from various environments. Pr…

Abundance of NARG, NIRK and NOSZ genes of denirifying bacteria during primary successions of a glacier foreland

2007

Le Priming Effect dans le sol : mécanismes, acteurs et conséquences sur les services écosystémiques dans un contexte de changement global

2022

The priming effect (PE) is a key mechanism contributing to the carbon balance of the soil ecosystem. Almost 100 years of research since its discovery in 1926 have led to a rich body of scientific publications to identify the drivers and mechanisms involved. A few review articles have summarised the acquired knowledge; the last major one was published in 2010. Since then, knowledge on the soil microbial communities involved in PE and in PE + C sequestration mechanisms has been considerably renewed.This article reviews current knowledge on soil PE to state to what extent new insights may improve our ability to understand and predict the evolution of soil C stocks. We propose a framework to un…

Acute Postcataract Surgery Endophthalmitis Due to Streptococcus Species Differs From Endophthalmitis Due to Staphylococcus Species at Presentation

2009

Purpose: : To correlate the presenting clinical ophthalmic features with the bacterial identification in 100 patients with acute post catarcat endophthalmitis enrolled in the FRench Instutionnal ENdophthalmitis Study (FRIENDS).Methods: : Demographic data, past medical history and initial eye examination were recorded in a standardized form in 100 patients with acute endophthalmitis after cataract extraction (< 6 weeks) in a prospective multicenter study. Relationship between microbiological identification (using conventional cultures and panbacterial PCR) and clinical factors at baseline was studied using univariate (ANOVA).Results: : 100 patients were hospitalized for endophthalmitis treat…