ABSTRACT
Management of the Mediterranean flat-headed root-borer, Capnodis tenebrionis, is critical due to the larvae's root localization. Neonate larvae can be exposed to natural enemies before penetrating the roots. Application of Metarhizium brunneum strain Mb7 and Beauveria bassiana strain GHA formulations on rice granules was investigated for their efficacy against C. tenebrionis larvae. Mb7 application, evaluated on apricot twigs, significantly and dose-dependently reduced colonization rates of neonates, with highest mortality at 108 conidia/g soil. Neonate susceptibility to Mb7 and GHA was evaluated on potted rootstocks (GF677 almond × peach, 2729 plum) planted in entomopathogenic fungi (EPF)-premixed soil (1.3-1.6 × 105 conidia/cm3 soil) or in EPF-free soil surface-treated with 5 g Mb7 fungal granules (1.25 × 109 conidia). Larval colonization rates were reduced 7.4-fold in 2729 by both fungi; only Mb7 completely prevented colonization of GF677 by larvae. Larvae inside plant galleries exhibited mycosis with EPF-treated soils and both fungi proliferated on larval frass. Mb7 conidia germinated in the rhizosphere of GF677, and conidia of both fungi remained viable throughout the trial. Galleria baiting technique was used on EPF-treated soil to evaluate EPF infectivity over time; Mb7 and GHA persisted 180 and 90 days post inoculation, respectively. The formulation (fungus-covered rice grains), delivery method (mixing with soil) and persistence (3-6 months) of Mb7 and GHA are feasible for potential field application to control C. tenebrionis.
ABSTRACT
Los PCBs por sus propiedades físicas y químicas son usados en diferentes sectores industriales; sus productos de desechos y su almacenamiento inadecuado han contaminado ambientes como suelos y aguas poniendo en peligro la supervivencia en los ecosistemas. Sin embargo, algunos seres vivos son capaces de adaptarse. Los bifenilos policlorados (PCBs) son compuestos orgánicos de hidrocarburos sintéticos formados por dos anillos de benceno unidos por un enlace de carbono; comprenden una clase de 209 compuestos individuales, isómeros y congéneres. Su objetivo fue aislar e identificar hongos filamentosos capaces de tolerar y adaptarse para sobrevivir en condiciones adversas en el ecosistema suelo contaminado por el xenobiótico PCBs, presente en aceites dieléctricos usados (ADU) en un sector industrial de Barranquilla. Los hongos aislados de los géneros Aspergillus sp, Alternaría sp, Phoma sp, Rhizopus sp. sobrevivieron a concentraciones de ADU 20 %, y a 200 ppm de PCBs
PCBs for their physical and chemical properties are used in different industrial sectors; waste products and inadequate storage have polluted environments such as soils and water that endanger ecosystem survival. However, some living beings are able to adapt. Polychlorinated biphenyls (PCBs) are organic synthetic hydrocarbon compounds formed by two benzene rings bonded by a carbon bond, comprise a class of 209 individual compounds, isomers and congeners. Its objective was the isolation and identification of filamentous fungi capable of tolerating and adapting to survive in adverse conditions in the soil ecosystem contaminated by the xenobiotic PCBs, present in used dielectric oils (ADU) in an industrial sector of Barranquilla. The isolated fungi of the genus Aspergillus sp, Alternaria sp, Phoma sp, Rhizopus sp. survived concentrations of 20% ADU, and 200 ppm of PCBs.
Subject(s)
Polychlorinated Biphenyls , Saturated Soils , Ecosystem , FungiABSTRACT
Paracoccidioides brasiliensis PbP27 gene encodes a protein localized in both the fungal cytoplasm and cell wall. The parasitic infectious form produces this protein preferentially with the gene's expression varying between the fungus phylogenetic species. The biological function of the native p27 has yet to be determined during either growth of the yeast or host infection. Therefore, in this study, through the use of antisense RNA technology and Agrobacterium tumefaciens-mediated transformation, we generated mitotically stable PbP27 mutants (PbP27 aRNA) with the goal to evaluate the role of p27 in the biology and virulence of this fungus. PbP27 expression was reduced 60-75% in mutants, as determined by real-time PCR in correlation with a decrease in p27 expression. No alterations in the growth curve or in the ability to shift from mycelia to yeast or from yeast to mycelia were observed in PbP27 aRNA strains; however, we did observe a reduction in cell vitality. Moreover, a decrease in cell viability of PbP27 aRNA yeast cells after interaction with IFN-γ-stimulated macrophages was detected. Based on these results, we propose that p27 plays a role in yeast cell architecture and represents one of the mechanisms employed by this fungus for its interaction with the monocyte/macrophage system.