Search results for "pathogenic"
showing 10 items of 203 documents
Biocontrol of Phelipanche ramosa, a parasitic weed of rapeseed in France, using soil-borne fungi
2021
National audience; Phelipanche ramosa is a major holoparasitic weed, which became a major agronomic problemfor rapeseed crops in France. Weed control in rapeseed does not have a direct impact on thisparasitic weed whose half of the reproductive cycle occurs on the root system of its host. Since1990, broomrape expanded its distribution area starting from the Poitou-Charentes region.Necrosis symptoms on broomrapes from this region should be indicators of potentialpathogenic fungi. Furthermore, these pathogenic fungi should be able to infest differentbroomrape stages. The aim of my thesis is to contribute to the evaluation of an integrated controlsolution for this parasitic weed and focus on t…
Relationship between HLA I surface expression and different cytopathic effects produced after herpes simplex virus infection in vitro.
1992
In the present study, we investigated the effects of herpes simplex virus (HSV) infection on the expression of HLA class I antigens and beta 2-microglobulin in human fibroblasts. The mRNA abundance for HLA class I was shown to be strongly reduced after infection with HSV strains either producing cell rounding or fusion from within (FFWI), however, HLA class I expression on the surface of cells is strongly reduced only after appearance of FFWI. Using a ts mutant (ts 78R) or CyA in combination with a fusion from without (FFWO) inducing strain of HSV, this loss of HLA class I antigens is assumed to be correlated to the rearrangement of the cell membrane during the fusion process itself as a la…
An investigation of the bacteriocinogenic potential of lactic acid bacteria associated with wheat (triticum durum) kernels and non-conventional flours
2008
One hundred and thirty-seven lactic acid bacteria (LAB), previously isolated from wheat (Triticum durum) grains and non-conventional flour samples, were tested for the production of antibacterial substances. A total of 16 strains (5 Enterococcus faecium, 5 Enterococcus mundtii, 4 Pediococcus pentosaceus, 1 Lactobacillus coryniformis and 1 Lactococcus garvieae) were found to inhibit the growth of Listeria innocua. The antibacterial activities were preliminarily investigated for their general behaviour with proteolytic (proteinase K, protease B and trypsin), amylolytic (α-amylase) and lipolytic (lipase) enzymes, after heat treatment, and exposure to different pHs and ethanol concentrations. B…
Metarhizium anisopliae, a potential agent for the control of grape phylloxera
2004
This investigation deals with the control effects of the insect pathogenic fungus Metarhizium anisopliae var. anisopliae on Daktulosphaira vitifoliae. In pot experiments, the soil surrounding phylloxera-infected grapes was inoculated with barley colonised with M. anisopliae. After thirty-two days, ineight of ten Metarhizium-applied pots nofresh phylloxera infections could be observed.In two of ten plants, a few fresh nodositiessingly occupied with phylloxera or phylloxeraeggs could be found. In all untreated plants,fresh nodosities with either single (two of sixplants) or multiple (four of six plants)occupation with phylloxera could be observed.M. anisopliae could be re-isolated in aconcent…
Differences in Attachment and Phagocytosis of Salmonella minnesota Strains (S Form, Re Mutant) by Mouse Peritoneal Macrophages: Participation of Endo…
1985
The virulence of bacteria in many phagocytic systems has been studied for several years and it is known that macrophages play an important role in host defence against invading microorganisms and in cooperation with cellular and humoral immune mechanisms. Pathogenic bacteria can be divided into two groups with regard to their fate within phagocytes: (a) extracellular bacteria which are promptly killed after phagocytosis and (b) facultative intracellular bacteria which are resistant to intracellular killing unless macrophages are activated. Humoral immune mechanisms (antibody, complement) deal mainly with extracellular bacteria, while cellular immune mechanisms (T cells, macrophages) deal wi…
Wanted : pathogenesis-related marker molecules for Fusarium oxysporum
2003
Summary Although Fusarium oxysporum pathogens cause severe wilts in about 80 botanical species, the mechanisms of pathogenicity and symptom induction are poorly understood. Knowledge about the genetic and biochemical pathways involved in the pathogenesis of F. oxysporum would be invaluable in getting targets for both fungicide development and search for biocontrol agents. In this respect, we described the main approaches that have been developed to identify some mechanisms underlying the pathogenesis of F. oxysporum . During the last decades, the potential functions triggering of F. oysporum pathogenicity have mainly been investigated by comparing soilborne pathogenic strains with nonpathog…
Probiotic properties of Brevibacillus brevis and its influence on sea bass (Dicentrarchus labrax) larval rearing
2012
Efficacy of Brevibacillus brevis strain and its influence on larval rearing of sea bass (Dicentrarchus labrax) were investigated in the present work. Biochemical analyses permit to identify this strain as B. brevis. This bacterium has an inhibitory effect against fish pathogenic bacteria, especially the genus of Vibrio. Enzymatic characterization revealed that B. brevis was lipase positive, amylase, lecithinase and caseinase negative. Adherence assays to abiotic surfaces and challenge test with Artemia larvae demonstrate that B. brevis was fairly adherent and play an important role in the enhancement of the protection of Artemia culture against pathogens. Treatment of sea bass larvae with B…
Modulation of immune responses ofRhynchophorus ferrugineus(Insecta: Coleoptera) induced by the entomopathogenic nematodeSteinernema carpocapsae(Nemat…
2014
Aim of this study was to investigate relationships between the red palm weevil (RPW) Rhynchophorus ferrugineus (Olivier) and the entomopathogenic nematode Steinernema carpocapsae (EPN); particularly, the work was focused on the immune response of the insect host in naive larvae and after infection with the EPN. Two main immunological processes have been addressed: the activity and modulation of host prophenoloxidase-phenoloxidase (proPO) system, involved in melanization of not-self and hemocytes recognition processes responsible for not-self encapsulation. Moreover, immune depressive and immune evasive strategies of the parasite have been investigated. Our results suggest that RPW possess a…
Latent measles virus infection in Vero cells depending on a temperature-sensitive phenomenon.
1978
A latent infection by measles virus in a line of Vero cells could be maintained only at 37 degrees C. The conditions of temperature nonpermissiveness were associated with some block in virus production and/or release and with the establishment of an autointerference phenomenon. Reduction of the incubation temperature to 33.5 degrees C induced a rather rapid transition from the latent to a lytical infection with a recue of virus. The rescued virus exhibited a restricted capacity to grow at 37 degrees C.
Laccases: structure, reactions, distribution
2004
Laccases (EC 1.10.3.2, p-diphenol: dioxygen oxidoreductases) are multi-copper proteins that use molecular oxygen to oxidize various aromatic and non-aromatic compounds by a radical-catalyzed reaction mechanism. The enzymes are involved in the pathogenicity, immunity and morphogenesis of organisms and in the metabolic turnover of complex organic substances such as lignin or humic matter. Owing to their high non-specific oxidation capacity, laccases are useful biocatalysts for diverse biotechnological applications. Until recently, laccases were only found in eukaryotes (fungi, higher plants, insects), but now there is strong evidence for their widespread distribution in prokaryotes and the fi…