Behavioral and electrophysiological response of Rhynchophorus palmarum (L., 1764) (Coleoptera: Curculionidae) to volatile compounds of natives entomopatogenic fungi

Rhynchophorus palmarum es plaga relevante en palmeras (Arecaceae) en Brasil. Su respuesta comportamental (olfatometría) y electrofisiológica (electroantenografía, sola y acoplada a cromatografía) se estudió frente a compuestos orgánicos volátiles emitidos por hongos entomopatógenos nativos aislados en Coruripe (Alagoas, Brasil) mediante aireación durante 24 horas. El aislado CVAD01 no originó respuesta comportamental significativa, pero el CVAD02 originó atracción significativa en machos. Los bioensayos electrofisiológicos mostraron actividad antenal en los dos sexos de R. palmarum frente a los componentes volátiles de los extractos de los dos hongos identificados. Los análisis cromatográficos de los extractos indicaron perfiles de compuestos orgánicos volátiles con la presencia de dos alcoholes, tres hidrocarburos aromáticos, dos monoterpenos, tres cetonas y tres hidrocarburos lineales. Rhynchophorus palmarum is a major pest of palms (Arecaceae) in Brasil. Both the behavioral (olfactometry) and electrophysiological (electroantennography, both alone and coupled to chromatography) was studied against volatile organic compounds emitted by native entomopathogenic fungi isolated from Coruripe (Alagoas, Brazil). Fungal isolates were identified by aeration system for 24 hours. CVAD01 did not cause a significant behavioral response; however, males were significantly attracted to CVAD02 extracts. Electrophysiological bioassays showed antennal activity, in both sexes, to volatile components of the two identified native fungi. The chromatographic analysis of the extracts indicated profiles of volatile organic compounds with the presence of three alcohol, three aromatics, three ketones, and four hydrocarbons.

Bioaugmentation of Native Fungi, an Efficient Strategy for the Bioremediation of an Aged Industrially Polluted Soil With Heavy Hydrocarbons

The concurrence of structurally complex petroleum-associated contaminants at relatively high concentrations, with diverse climatic conditions and textural soil characteristics, hinders conventional bioremediation processes. Recalcitrant compounds such as high molecular weight polycyclic aromatic hydrocarbons (HMW-PAHs) and heavy alkanes commonly remain after standard soil bioremediation at concentrations above regulatory limits. The present study assessed the potential of native fungal bioaugmentation as a strategy to promote the bioremediation of an aged industrially polluted soil enriched with heavy hydrocarbon fractions. Microcosms assays were performed by means of biostimulation and bioaugmentation, by inoculating a defined consortium of six potentially hydrocarbonoclastic fungi belonging to the genera Penicillium, Ulocladium, Aspergillus, and Fusarium, which were isolated previously from the polluted soil. The biodegradation performance of fungal bioaugmentation was compared with soil biostimulation (water and nutrient addition) and with untreated soil as a control. Fungal bioaugmentation resulted in a higher biodegradation of total petroleum hydrocarbons (TPH) and of HMW-PAHs than with biostimulation. TPH (C14-C35) decreased by a 39.90 ± 1.99% in bioaugmented microcosms vs. a 24.17 ± 1.31% in biostimulated microcosms. As for the effect of fungal bioaugmentation on HMW-PAHs, the 5-ringed benzo(a)fluoranthene and benzo(a)pyrene were reduced by a 36% and 46%, respectively, while the 6-ringed benzoperylene decreased by a 28%, after 120 days of treatment. Biostimulated microcosm exhibited a significantly lower reduction of 5- and 6-ringed PAHs (8% and 5% respectively). Higher TPH and HMW-PAHs biodegradation levels in bioaugmented microcosms were also associated to a significant decrease in acute ecotoxicity (EC50) by Vibrio fischeri bioluminiscence inhibition assays. Molecular profiling and counting of viable hydrocarbon-degrading bacteria from soil microcosms revealed that fungal bioaugmentation promoted the growth of autochthonous active hydrocarbon-degrading bacteria. The implementation of such an approach to enhance hydrocarbon biodegradation should be considered as a novel bioremediation strategy for the treatment of the most recalcitrant and highly genotoxic hydrocarbons in aged industrially polluted soils.

Hordeum vulgare marketed as food contains potential fungi that synthesize mycotoxin.

The grains of H. Vulgare commonly used for the elaboration of meals for humans and animals, could be contaminated with propagules of native fungi resulted from the intensive agricultural system of production. In addition, the unsuitable storage conditions could strongly influence the growing of undesirable fungi which could potential synthetiz emyco toxins. The aim of the present research work was the isolation of Aspergillus potential to synthetize ochratoxin A from the commercially available in H. vulgare. To this purpose, the grains were collected from various local stores, from grain of H. vulgare. Aspergillus were isolated in potato dextrose and in a Sabourauddextroseagar to determine the density and diversity. The potential for the synthesis of ochratoxin A by Aspergillus strains was then evaluated. The results were statistically evaluated using the software Anova/Turkey. Results indicate the presence of a relatively high number of propagules of Aspergillus spp which are contaminating the H. vulgare. Furthermore, 67% of the fungi present in H. vulgare have the potential to synthetize ochratoxin A. These results demonstrate the risk of consumption of those grains by humans.

Acquisition of fungi from the environment modifies ambrosia beetle mycobiome during invasion

Microbial symbionts can play critical roles when their host attempts to colonize a new habitat. The lack of symbiont adaptation can in fact hinder the invasion process of their host. This scenario could change if the exotic species are able to acquire microorganisms from the invaded environment. Understanding the ecological factors that influence the take-up of new microorganisms is thus essential to clarify the mechanisms behind biological invasions. In this study, we tested whether different forest habitats influence the structure of the fungal communities associated with ambrosia beetles. We collected individuals of the most widespread exotic (Xylosandrus germanus) and native (Xyleborinus saxesenii) ambrosia beetle species in Europe in several old-growth and restored forests. We characterized the fungal communities associated with both species via metabarcoding. We showed that forest habitat shaped the community of fungi associated with both species, but the effect was stronger for the exotic X. germanus. Our results support the hypothesis that the direct contact with the mycobiome of the invaded environment might lead an exotic species to acquire native fungi. This process is likely favored by the occurrence of a bottleneck effect at the mycobiome level and/or the disruption of the mechanisms sustaining co-evolved insect-fungi symbiosis. Our study contributes to the understanding of the factors affecting insect-microbes interactions, helping to clarify the mechanisms behind biological invasions.

Biodegradation of Residues from the Palo Santo (Bursera graveolens) Essential Oil Extraction and Their Potential for Enzyme Production Using Native Xylaria Fungi from Southern Ecuador

The degradation dynamics of lignin and cellulose were analyzed by means of a solid state biodegradation experiment, using residues from the essential oil extraction of the Palo Santo tree (Bursera graveolens). As such, two native Xylaria spp. and an exotic mushroom Trametes versicolor were incubated on the spent substrate (Residues of B. Graveolens, BGR’s). The relatively high lignin and cellulose contents of the BGRs (9.1% and 19%, respectively) indicated the potential of this resource for the production of methane (biogas) and ethanol. However, the degradation of the lignin and cellulose content could be traced back to the relatively high activity of the enzymes laccase, cellulase, and xylanase, produced by the fungi. The results showed that laccase (30.0 U/L and 26.6 U/L), cellulase (27.3 U/L and 35.8 U/L) and xylanase (189.7U/L and 128.3 U/L) activities of Xylaria feejeensis and Xylaria cf. microceras were generally higher than T. versicolor (9.0 U/L, 29.5 U/L, 99.5 U/L respectively). Furthermore, the total carbon (TC: 47.3%), total nitrogen (TN: 1.5%), total phosphorus (TP: 0.2%) and total potassium (TK: 1.2%) dynamics were analyzed during the experiment and their importance for the degradation process highlighted. The results of this work might serve as guidance for future studies in dry forest areas, while furthering the understanding of the potential use of native fungi as ecologic lignocellulosic decomposers and for industrial proposes.

Isolation and identification of native degrading fungi from Wastewater's pollutants in cardboard recycling industry

Introduction: By increasing the amount and diversity of bio-environmental wastewater pollutants, it is essential to be controlled and planed the environmental contaminants to eliminate or minimize. Cardboard recycling industry wastewater has the potential of environmental pollution; it is contaminated with various fungal species that may be effective in the decomposition and removal of pollutants. The aim of this study was the isolation and identification of native fungal species that decontaminate organic pollutants in the cardboard recycling industry wastewaters. Methods: In this study, which is a descriptive study, samples were randomly taken from different area of wastewater of cardboard recycling industry. Samples were cultured on Saboraud dextrose agar medium for isolation of probable fungal species, which decomposers of wastewater. The isolated fungal colonies were enumerated and purified based on morphological characteristics and microscopic analyzing as far as possible. Results: The average count of the total number of fungi species in wastewater of cardboard recycling industry was 2.5×102 CFU/ml of these 2.1×101 were saprophytic fungi. The most prevalent fungal species were identificated from the wastewater include Aspergillus niger, Aspergillus flavus, Penicillum, Geotrichum, Mucor, Drechselera, Paecillomyces, Alternaria, Fusarium and Absidia. The highest frequency of fungal species Aspergillus nige, Aspergillus flavus and Penicillum were 30.89%, 22.76% and 14.63% respectively. Conclusion: It seems that native fungi isolated from the cardboard recycling industry wastewater in this study are from fungi that have the potential for bioremediation of wastewater contaminants based on scientific literature and can be used for evaluating of their ability to decompose wastewater from this industry.