Trichoderma stromaticum, T. rossicum and newly discovered species form a unique lineage in Trichoderma. Phylogenetic and phenotypic diversity in Trichoderma stromaticum are examined in the light of reported differences in ecological parameters and AFLP patterns. Multilocus phylogenetic analysis using 4 genes (tef1, rbp2, cal, chi18-5) did not reveal phylogenetic basis for the two reported divergent AFLP patterns or for ecological parameters; however, this analysis does indicate incomplete speciation with one supported clade derived from within T. stromaticum that corresponds to AFLP Group 2 of de Souza et al. (2006, Phytopathology 96:61-67). Trichoderma stromaticum is known only from tropical America and is typically found in association with Theobroma cacao infected with Moniliophthora perniciosa. It is reported here for the first time on pseudostromata of M. roreri in Peru. Strains of T. stromaticum also have been isolated as endophytes from stems of Theo. cacao. There are no recognized close relatives of T.stromaticum in tropical America. The closest relatives of T. stromaticum are collected in Africa and Thailand; somewhat more distantly related are T. rossicum and T. barbatum, both found in north temperate regions.

Glioblastomas (GBM) are aggressive brain tumors with very poor prognosis. While silver nanoparticles represent a potential new strategy for anticancer therapy, the silver/silver chloride nanoparticles (Ag/AgCl-NPs) have microbicidal activity, but had not been tested against tumor cells. Here, we analyzed the effect of biogenically produced Ag/AgCl-NPs (from yeast cultures) on the proliferation of GBM02 glioblastoma cells (and of human astrocytes) by automated, image-based high-content analysis (HCA). We compared the effect of 0.1-5.0 µg mL Ag/AgCl-NPs with that of 9.7-48.5 µg mL temozolomide (TMZ, chemotherapy drug currently used to treat glioblastomas), alone or in combination. At higher concentrations, Ag/AgCl-NPs inhibited GBM02 proliferation more effectively than TMZ (up to 82 and 62% inhibition, respectively), while the opposite occurred at lower concentrations (up to 23 and 53% inhibition, for Ag/AgCl-NPs and TMZ, respectively). The combined treatment (Ag/AgCl-NPs + TMZ) inhibited GBM02 proliferation by 54-83%. Ag/AgCl-NPs had a reduced effect on astrocyte proliferation compared with TMZ, and Ag/AgCl-NPs + TMZ inhibited astrocyte proliferation by 5-42%. The growth rate and population doubling time analyses confirmed that treatment with Ag/AgCl-NPs was more effective against GBM02 cells than TMZ (~ 67-fold), and less aggressive to astrocytes, while Ag/AgCl-NP + TMZ treatment was no more effective against GBM02 cells than Ag/AgCl-NPs monotherapy. Taken together, our data indicate that 2.5 µg mL Ag/AgCl-NPs represents the safest dose tested here, which affects GBM02 proliferation, with limited effect on astrocytes. Our findings show that HCA is a useful approach to evaluate the antiproliferative effect of nanoparticles against tumor cells.

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