Cecilia Cristina Carmaran

Diversity and significance of fungal endophytes from living stems of naturalized trees from Argentina

Fungal endophytes inhabit healthy tissues of all terrestrial taxa studied to date; however, fungi associated with woody tissue have been frequently overlooked. Here, we examined endophytes associated with healthy living stems of tree species exotic to Argentina (Broussonetia papyrifera, Celtis occidentalis and Ligustrum lucidum) in a natural reserve. To achieve this objective, fungi were induced to develop within the wood by drying sections of branches. For comparison purposes, a study of the organisms present on superficial and inner bark was carried out. Fifty-seven strains belonging to 12 different taxa, dominated by the anamorphic states of ascomycetes, were obtained from the 180 cultured chips. Coprinellus micaceus, Lecythophora hoffmannii and Rhizopus microsporus are cited for the first time as endophytes. Only two taxa appeared on more than one tree species. Assemblages of fungi obtained from each tree species were different and the fungal endophytes isolated were very different from those previously recorded for leaves of the same hosts in the same area. Thus, it is probable that the endophytes exhibit host- and tissue-specificity. Considering three main factors: 1. the invasive nature of two of the selected hosts, 2. the evaluation of woody tissue and 3. the taxonomic identity of the fungal isolations, hypotheses concerning ecological implications are here discussed. In this sense, Broussonetia papyrifera and Ligustrum lucidum could be considered as sources of potential inoculum for native plants, especially in protected areas, and the high diversity of fungal species living within the tissues of the hosts studied suggests their potential as important fungal reservoirs to be taken into account in conservation issues.

Influence of strong bases on the synthesis of silver nanoparticles (AgNPs) using the ligninolytic fungi Trametes trogii

Silver nanoparticles (AgNPs) were biosynthesized using fungal extract of Trametes trogii, a white rot basidiomycete involved in wood decay worldwide, which produces several ligninolytic enzymes. According to previous studies using fungi, enzymes are involved in nanoparticles synthesis, through the so-called green synthesis process, acting as reducing and capping agents. Understanding which factors could modify nanoparticles’ shape, size and production efficiency is relevant. The results showed that under the protocol used in this work, this strain of Trametes trogii is able to synthesize silver nanoparticles with the addition of silver nitrate (AgNO3) to the fungal extract obtained with an optimal incubation time of 72 h and pH 13, using NaOH to adjust pH. The progress of the reaction was monitored using UV–visible spectroscopy and synthesized AgNPs was characterized by scanning electron microscope (SEM), through in-lens and QBDS detectors, and energy-dispersive X-ray spectroscopy (EDX). Additionally, SPR absorption was modeled using Mie theory and simple nanoparticles and core-shell configurations were studied, to understand the morphology and environment of the nanoparticles. This protocol represents a simple and cheap synthesis in the absence of toxic reagents and under an environmentally friendly condition.

Physicochemical Properties and Field Evaluation of Monolithic Wax Formulations for the Controlled Release of a Forest Pest Pheromone

Fil: Slodowicz, Mariel Pamela. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Investigaciones Cientificas y Tecnicas para la Defensa. Centro de Investigacion de Plagas e Insecticidas; Argentina

Autofluorescence and Ultrastructure in the Myxomycete Diachea leucopodia (Physarales)

Autofluorescence is reported for the first time in Myxomycete fruiting bodies. Ultrastructure of stalked sporangia of Diachea leucopodia (Didymiaceae, Physarales) was studied using scanning and transmission electron microscopy, energy-dispersive X-ray microanalysis, and fluorescence microscopy. External and internal properties of the peridium that surround the spores and capillitium exhibit autofluorescence. The stalk is composed of calcareous granules and energy-dispersive X-ray microanalysis demonstrates that the elemental composition of the peridium, capillitium, and stalk has varying concentrations of calcium.