Detection of accase target-site resistant Alopecurus myosuroides huds (black-grass) in Belgian populations

Black-grass is a common grass weed, widely spread in Northern Europe and also in Belgium. For ages, it has been an increasing problem in industrial crops, especially winter cereals. The first case of resistance in Belgium was reported in 1996 by Robert Bulcke (Eelen et al., 1996). Yet the resistance mechanism was not specified. Since then, no more information was published about the evolution Belgium, while research continued in the United Kingdom and in France. Moreover, during the last decade, progress in molecular biology allowed to highlight the mechanism of target-site resistance. A simple PCR method allows to detect the mutation conferring resistance to herbicide. After two years of resistance monitoring in Belgium, mostly in the Walloon part, some populations have been clearly identified as highly resistant to ACCase inhibitor. These populations have been tested by molecular biology so as to detect the single nucleotide polymorphism (SNP) involved in this case. The method employed was the Polymerase Chain Reaction Allele Specific Assays (PASA: Délye, 2002a) for the mutation Ile-1781-Leu that confers a target-site resistance to ACCase inhibitors. Those analyses were performed on plant material issued from bioassays, either in glasshouses or in Petri dishes. Leaves have been collected from plants which survived a fenoxaprop-P treatment applied in a glasshouse single dose assay. Seedlings from resistant populations grown in Petri dishes containing either fenoxaprop-P or cycloxydim provided the second type of sample. Ile1781 mutants were discovered within three populations. Each mutant plant was heterozygote. Five of those samples have been sequenced to confirm PASA results and everyone was matching. Moreover, they were all issued from Petri dishes containing cycloxydim, known to be unaffected by enhanced metabolism, confirming that theses populations are indeed target-site resistant

A preliminary study of cross correlation between lithology and K airborne radiometry in the Belgian Ardennes

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The Natural Element Method Applied to Solve Electromagnetic Scattering Problem

International audienceIn this paper, the natural element method with the traditional first order absorbing boundary condition (NEM-ABC) is applied to solve the classical electromagnetic scattering problem. The result is compared with the well known FEM-ABC and shows the applicability of the method and its relevanc

Data-driven Modeling of Building Consumption Profile for Optimal Flexibility: Application to Energy Intensive Industry

International audienceDespite the vast research on the flexibility of buildings consumption, current literature is more about predicting the impacts of energy flexibility than fo-cusing on its modeling. In this paper, a methodology is provided to go from data-driven modeling of the load consumption to an optimization problem with a Mixed-Integer Linear Programming (MILP) formulation. Illustrated on an Energy Intensive Industries (EII) with an economic point of view, the methodology is suitable for any consumption site, allowing optimal energy planning studies at the district scale. Thus, it facilitates the definition of flexibility strategies to exploit the complementary of uses of the districts

Molecular characterisation of Staphylococcus aureus strains isolated from small and large ruminants reveals a host rather than tissue specificity.

International audienceStaphylococcus aureus is an important pathogen in domestic ruminants. The main objective of this study was to determine the similarity of epidemiologically unrelated S. aureus isolates from bovine, ovine, and caprine hosts regardless the locus of isolation (nares and udder). By pulsed-field gel electrophoresis, seven major pulsotypes were identified among 153 isolates recovered from 12 different regions of France as well as from Brazil, the USA and Belgium. Typing of the accessory gene regulator (agr) and capsular (cap) serotype was carried out on all the isolates and revealed the predominance of agr I and III and of cap8 regardless the ruminant host species. Screening for methicilin-resistant S. aureus (MRSA) was carried out by disk diffusion and revealed a prevalence of only 3.2% of MRSA among the strains tested. These results suggest the existence of a host rather than tissue specificity among S. aureus isolates colonising the ruminant species and suggest a limited transmission of those isolates between large (bovine) and small (ovine-caprine) ruminants. The agr class and cap types correlated with pulsotype clusters rather than with a specific host species. Antimicrobial resistance appears not to have contributed to the predominance of any given genotypes, and MRSA prevalence appears very low in ruminant isolates

New thermal insulation fiberboards from cake generated during biorefinery of sunflower whole plant in a twin-screw extruder

The objective of this study was to manufacture new thermal insulation fiberboards by thermo-pressing. The starting material was a slightly deoiled cake (17.6% oil content), generated during the biorefinery of sunflower (Helianthus annuus L.) whole plant in a co-rotating (Clextral BC 45, France) twin-screw extruder. All fiberboards produced were cohesive mixtures of proteins and lignocellulosic fibers, acting respectively as binder and reinforcing fillers in what could be considered as a natural composite. The molding experiments were conducted using a 400 ton capacity heated hydraulic press (Pinette Emidecau Industries, France). The influence of molding conditions on board density, mechanical properties and heat insulation properties was examined. Molding conditions included mold temperature (140-200°C), pressure applied (150-250 kgf/cm²) and molding time (40-76 s), and these greatly affected board density and thus the mechanical and heat insulation properties. Board density increased with increasingly extreme molding conditions, rising from 500 to 858 kg/m³. The mechanical properties increased at the same time (from 52 to 660 kPa for flexural strength at break, from 5.9 to 49.4 MPa for elastic modulus, from 0.5 to 7.7 kJ/m² for Charpy impact strength, and from 19.2 to 47.1° for Shore D surface hardness). Conversely, heat insulation properties improved with decreasing board density, and the lowest thermal conductivity (88.5 mW/m K at 25°C) was obtained with the least dense fiberboard. The latter was produced with a 140°C mold temperature, a 150 kgf/cm² pressure applied and a 40 s molding time. A medium mold temperature (160°C) was needed to obtain a good compromise between mechanical properties (272 kPa for flexural strength at break, 26.3 MPa for elastic modulus, 3.2 kJ/m² for Charpy impact strength, and 37.3° for Shore D surface hardness), and heat insulation properties (99.5 mW/m K for thermal conductivity).The corresponding board density was medium (687 kg/m³). Because of their promising heat insulation properties, these new fiberboards could be positioned on walls and ceilings for thermal insulation of buildings. The bulk cake also revealed very low thermal conductivity properties (only 65.6 mW/m K at 25°C) due to its very low bulk density (204 kg/m³). It could be used as loose fill in the attics of houses

Staphylococcus aureus seroproteomes discriminate ruminant isolates causing mild or severe mastitis

Staphylococcus aureus is a major cause of mastitis in ruminants. In ewe mastitis, symptoms range from subclinical to gangrenous mastitis. S. aureus factors or host-factors contributing to the different outcomes are not completely elucidated. In this study, experimental mastitis was induced on primiparous ewes using two S. aureus strains, isolated from gangrenous (strain O11) or subclinical (strain O46) mastitis. Strains induced drastically distinct clinical symptoms when tested in ewe and mice experimental mastitis. Notably, they reproduced mild (O46) or severe (O11) mastitis in ewes. Ewe sera were used to identify staphylococcal immunoreactive proteins commonly or differentially produced during infections of variable severity and to define core and accessory seroproteomes. Such SERological Proteome Analysis (SERPA) allowed the identification of 89 immunoreactive proteins, of which only 52 (58.4%) were previously identified as immunogenic proteins in other staphylococcal infections. Among the 89 proteins identified, 74 appear to constitute the core seroproteome. Among the 15 remaining proteins defining the accessory seroproteome, 12 were specific for strain O11, 3 were specific for O46. Distribution of one protein specific for each mastitis severity was investigated in ten other strains isolated from subclinical or clinical mastitis. We report here for the first time the identification of staphylococcal immunogenic proteins common or specific to S. aureus strains responsible for mild or severe mastitis. These findings open avenues in S. aureus mastitis studies as some of these proteins, expressed in vivo, are likely to account for the success of S. aureus as a pathogen of the ruminant mammary gland

Development of serological proteome analysis of mastitis by Staphylococcus aureus in ewes.

International audienceStaphylococcus aureus is a major agent of mastitis in ruminants worldwide. So far, efficient measures for its prophylaxis (including vaccination) have proven to be unsuccessful and there is a need for a better understanding of the host response to udder infection by S. aureus. Serological proteome analysis (SERPA) is a promising technique that can be used to identify S. aureus immuno-dominant determinants providing that bacterial culture conditions used to grow S. aureus strains for protein sample preparation mimic the context of mastitis. A S. aureus strain was used in experimental mastitis to generate sheep serum used to determine the best growth conditions for SERPA. Sera collected in the field from different ewes suffering from mastitis by S. aureus were used to confirm experimental observations. Three different culture media (BHI, whey and iron-depleted RPMI) were tested. The influence of aeration and growth phase on protein production was also evaluated by immuno-detection of protein samples prepared from cultures grown in different conditions and obtained from different culture fractions (supernatant, cell wall, and total lysates). Our results showed that culturing in iron-depleted RPMI with (secreted proteins, prepared from stationary phase) or without aeration (cell wall proteins, prepared from early stationary phase, and total proteins, prepared from exponential phase) is the condition that best mimics growth in vivo during mastitis and this in vitro growth condition is to be used henceforth in experiments involving SERPA

Molecular Basis of Virulence in Staphylococcus aureus Mastitis

S. aureus is one of the main pathogens involved in ruminant mastitis worldwide. The severity of staphylococcal infection is highly variable, ranging from subclinical to gangrenous mastitis. This work represents an in-depth characterization of S. aureus mastitis isolates to identify bacterial factors involved in severity of mastitis infection

The Cyst-Dividing Bacterium Ramlibacter tataouinensis TTB310 Genome Reveals a Well-Stocked Toolbox for Adaptation to a Desert Environment

Ramlibacter tataouinensis TTB310T (strain TTB310), a betaproteobacterium isolated from a semi-arid region of South Tunisia (Tataouine), is characterized by the presence of both spherical and rod-shaped cells in pure culture. Cell division of strain TTB310 occurs by the binary fission of spherical “cyst-like” cells (“cyst-cyst” division). The rod-shaped cells formed at the periphery of a colony (consisting mainly of cysts) are highly motile and colonize a new environment, where they form a new colony by reversion to cyst-like cells. This unique cell cycle of strain TTB310, with desiccation tolerant cyst-like cells capable of division and desiccation sensitive motile rods capable of dissemination, appears to be a novel adaptation for life in a hot and dry desert environment. In order to gain insights into strain TTB310's underlying genetic repertoire and possible mechanisms responsible for its unusual lifestyle, the genome of strain TTB310 was completely sequenced and subsequently annotated. The complete genome consists of a single circular chromosome of 4,070,194 bp with an average G+C content of 70.0%, the highest among the Betaproteobacteria sequenced to date, with total of 3,899 predicted coding sequences covering 92% of the genome. We found that strain TTB310 has developed a highly complex network of two-component systems, which may utilize responses to light and perhaps a rudimentary circadian hourglass to anticipate water availability at the dew time in the middle/end of the desert winter nights and thus direct the growth window to cyclic water availability times. Other interesting features of the strain TTB310 genome that appear to be important for desiccation tolerance, including intermediary metabolism compounds such as trehalose or polyhydroxyalkanoate, and signal transduction pathways, are presented and discussed