Search results for "Conidium"
showing 10 items of 41 documents
Colonization of flax roots and early physiological responses of flax cells inoculated with pathogenic and nonpathogenic strains of Fusarium oxysporum
2003
ABSTRACT Fusarium oxysporum includes nonpathogenic strains and pathogenic strains that can induce necrosis or tracheomycosis in plants. The objective of this study was to compare the abilities of a pathogenic strain (Foln3) and a nonpathogenic strain (Fo47) to colonize flax roots and to induce early physiological responses in flax cell culture suspensions. Both strains colonized the outer cortex of the root; however, plant defense reactions, i.e., the presence of wall appositions, osmiophilic material, and collapsed cells, were less frequent and less intense in a root colonized by Foln3 than by Fo47. Early physiological responses were measured in flax cell suspensions confronted with germin…
Inhibition of Metarhizium anisopliae in the alimentary tract of the eastern subterranean termite Reticulitermes flavipes
2009
Reticulitermes flavipes workers were individually inoculated with 10,000 conidia of the entomopathogenic fungus Metarhizium anisopliae. After being kept in groups of 20 individuals for 1–6 d, histopathological approach showed that most of the inoculated conidia were groomed from the surface of the cuticle by nestmates within 24 h, and that a large number of conidia was subsequently found in different parts of the gut of the groomers. Our observations showed that, among thousands of conidia found in the termite's gut, conidial germination never occurred in all inspected specimens, even when the conidia had the chance to bind to the surface of the cuticular lining of the gut. In addition, whe…
INHIBITION OF THE FUNGAL PATHOGEN METARHIZIUM ANISOPLIAE IN THE ALIMENTARY TRACTS OF FIVE TERMITE (ISOPTERA) SPECIES
2010
We previously showed that in the subterranean termite Reticulitermes flavipes conidia of Metarhizium anisopliae did not germinate in the alimentary tract of living termites and the antifungal activity remained for 2 d post mortem in the gut. We have confirmed that this mechanism is common throughout the termite phylogeny by extending our observations to 5 additional species, from 5 different families. Grooming and ingestion of microorganisms from the cuticle ofnestmate was found to be consistent in all the species and none of the conidia found in the alimentary tracts germinated.
Cellular encapsulation in the eastern subterranean termite, Reticulitermes flavipes (Isoptera), against infection by the entomopathogenic fungus Meta…
2009
Reticulitermes flavipes workers were topically inoculated with approximately 10,000 conidia of the entomopathogenic fungus Metarhizium anisopliae. After being kept in groups of 20 individuals for 1-9 d, histopathological examination showed that termites had an individual immune reaction. The nodule formation at the point of entrance of the fungal hyphae was identified as a cellular encapsulation and the different steps in the nodule formation are described. The relative number of hemocytes per termite increased 24h after fungal exposure and remained high in the hemolymph for at least 3 d before decreasing back to pre-exposure levels. The role of an individual immune cellular reaction in soc…
Effects of resveratrol on the ultrastructure of Botrytis cinerea conidia and biological significance in plant/pathogen interactions
2012
International audience; Many roles have been ascribed to stilbenes, namely as antimicrobial, deterrent or repellent compounds in plants, protecting them from attacks by fungi, bacteria, nematodes or herbivores, acting both as constitutive and active defense (phytoalexin) compounds. More recently, stilbenes (especially resveratrol and its derivatives) were acclaimed for their wondrous effects and wide range of purported healing and preventive powers as cardioprotective, antitumor, neuroprotective and antioxidant agents. Although there is a huge number of works concerning the role of resveratrol in human health, reports on the antifungal activity of this compound are still scarce. This study …
Assessment of azole fungicides as a tool to control growth of Aspergillus flavus and aflatoxin B1 and B2 production in maize
2017
ABSTRACTAspergillus flavus is a highly aflatoxin (AF)-producing species infecting maize and other crops. It is dominant in tropical regions, but it is also considered an emerging problem associated with climate change in Europe. The aim of this study was to assess the efficacy of azole fungicides (prochloraz, tebuconazole and a 2:1 (w/w) mixture of prochloraz plus tebuconazole) to control the growth of A. flavus and AF production in yeast-extract–sucrose (YES) agar and in maize kernels under different water activities (aw) and temperatures. Aflatoxins B1 and B2 were determined by LC with fluorescence detection and post-column derivatisation of AFB1. In YES medium and maize grains inoculated…
Verrucous Plaque With Unusually Large Candida Blastoconidia: A Unique Clinicopathological Presentation of Systemic Mucocutaneous Candidiasis.
2018
Mucocutaneous candidiasis is a common infection affecting both immunocompetent and immunosuppressed individuals. Diversity in the clinical and histopathological presentation of mucocutaneous candidiasis is well known. However, the occurrence of cutaneous verrucous lesions and giant yeast-like structures has been rarely reported. In this article, we describe a case of disseminated mucocutaneous candidiasis in an immunosuppressed patient who presented as a verrucous plaque on the scrotum with giant Candida blastoconidia. This peculiar presentation expands the clinicopathological spectrum of mucocutaneous candidiasis and highlights the wide range of clinical manifestations and great morphologi…
Inoculation of airborne conidia of Penicillium chrysogenum on the surface of a solid medium
2016
International audience; To reproduce a fungal contamination of food products by airborne conidia, a method to inoculate a few number (in the range 1-9) of conidia on the surface of agar media was developed. This technique would allow to determine accurately the time to detection of fungal colonies, then the mould free shelf-life of food products by using dry conidia. The method was based on dry-harvesting the conidia in the lid by gently taping the bottom of the dishes where sporulating mycelium was grown, retaining the conidia on glass beads, and, aseptically transferring the beads to successive Petri dishes to "dilute" the samples. Among the eleven factors tested by means of an experiment…
Assessment of allyl isothiocyanate as a fumigant to avoid mycotoxin production during corn storage
2016
The occurrence of fungi and mycotoxins in foods modify sensorial properties and represents a health risk for consumers, and the use of natural antimicrobials may be an alternative to reduce this problem. The objective of this study was evaluate the potential of allyl isothiocyanate (AITC) in inhibit the production of mycotoxins in corn kernels by Aspergillus parasticus, Fusarium tricinctum, Fusarium verticillioides, Alternaria alternata and Gibberela zeae. Kernels were treated with gaseous AITC at 50, 100 or 500 μL/L during 48 h in hermetic flasks. Then, flasks were opened for 24 h and 100 g of corn were inoculated with 105 conidia/g of either fungal species. Flasks were kept at 23 °…
Immunodetection of CD45 epitopes on the surface of Candida albicans cells in culture and infected human tissues.
2000
Candida albicans is a leading cause of disseminated fungal infection in immunocompromised patients. Candida-host cell interactions are mediated at the cell surface. Since blood-group I epitopes have been detected on the surface of C albicans cells, we investigated whether CD45, the molecule that carries the I antigen on human lymphocytes, is present on the C albicans cell surface, in culture and in human tissue specimens of human candidiasis. By using monoclonal antibodies to CD45, CD45RO, and CD45RA, we found a strong immunoreactivity at the cell surface of blastoconidia bearing germ tubes but weak or no immunostaining of the germ tubes themselves. In human tissues, immunostaining of C alb…