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Previously, our study reported that β-(1→3,1→6)-ᴅ-glucans produced by endophytes Diaporthe sp. G27-60 and G65-65 (GenBank accession codes JF766998 and JF767007, respectively) are promising antiproliferative agents against human breast carcinoma (MCF-7) and hepatocellular carcinoma (HepG2-C3A) cells. However, effects of Diaporthe exopolysaccharides on eukaryotic healthy cells are not described in current literature. The fungus Metarhizium anisopliae has been employed as teste-system to evaluate the toxicity of pharmaceutical and agricultural-interest substances, considering, among other parameters, conidia germination speed. The current study aimed to verify the effect of different concentrations of Diaporthe β-glucans on the germination speed of M. anisopliae. Conidia were incubated with β-glucans treatments (50, 200 and 400 μg/mL) at 28 ºC, sampled throughout 24 h and analyzed by light microscopy. At the end of 24 h of incubation, the amount of germinated conidia was ≈99% for controls and ranged from 97.7 to 98.6% for treatments. Bayesian analysis indicated that Diaporthe glucans had no toxicity on M. anisopliae and the curve of germination occurred as expected for this fungal strain. Considering the validity of filamentous fungi as model systems, these results are important data about the toxicity of these endophytic EPS on healthy cells and may be associated with previous results obtained for these polymers against tumor cells. Keywords: bayesian analysis, conidia germination, endophytic fungi, exopolysaccharide, fungal model-system.

Previously, our study reported that β-(1→3,1→6)-ᴅ-glucans produced by endophytes Diaporthe sp. G27-60 and G65-65 (GenBank accession codes JF766998 and JF767007, respectively) are promising antiproliferative agents against human breast carcinoma (MCF-7) and hepatocellular carcinoma (HepG2-C3A) cells. However, effects of Diaporthe exopolysaccharides on eukaryotic healthy cells are not described in current literature. The fungus Metarhizium anisopliae has been employed as teste-system to evaluate the toxicity of pharmaceutical and agricultural-interest substances, considering, among other parameters, conidia germination speed. The current study aimed to verify the effect of different concentrations of Diaporthe β-glucans on the germination speed of M. anisopliae. Conidia were incubated with β-glucans treatments (50, 200 and 400 μg/mL) at 28 ºC, sampled throughout 24 h and analyzed by light microscopy. At the end of 24 h of incubation, the amount of germinated conidia was ≈99% for controls and ranged from 97.7 to 98.6% for treatments. Bayesian analysis indicated that Diaporthe glucans had no toxicity on M. anisopliae and the curve of germination occurred as expected for this fungal strain. Considering the validity of filamentous fungi as model systems, these results are important data about the toxicity of these endophytic EPS on healthy cells and may be associated with previous results obtained for these polymers against tumor cells.

Endoglucanases are enzymes widely employed in different industrial fields, albeit with high production costs. Studies on new microbial sources and low-cost substrates are highly relevant, including those on agro-industrial. Current analysis evaluates peanut hull (PH) and sawdust (SD) as substrates for submerged cultures of 14 endophytic fungi isolated from grapevine (Vitis labrusca L.) cultivars Bordô and Concord. Endophytes were grown on a carboxymethylcellulose (CMC) medium and the cup plate assay showed that eight strains (belonging to genera Cochliobolus, Diaporthe, Fusarium and Phoma) had positive results: enzymatic halos ranged from 10.8±0.02 to 15.5±0.07 mm in diameter. Diaporthe sp. strains (GenBank accession codes KM362392, KM362368 and KM362378) and Fusarium culmorum KM362384 were highlighted as the most promising sources. Further, PH and SD as substrates for the fermentation of these fungi were evaluated by the cup plate assay and endoglucanase activity assay. Highest halo diameters were obtained for Diaporthe sp. KM362392: 16.1±0.01 mm (CMC), 14.5±0.01 mm (PH) and 14.7±0.03 mm (SD). The fungus also presented the highest levels of endoglucanase activity: analysis of variance revealed that CMC (3.52±0.98 μmol/min), PH (2.93±0.23 μmol/min) and SD (3.26±0.38 μmol/min) were similarly efficient as substrates. Results deepen knowledge on V. labrusca endophytes that may be endoglucanase sources, even though further optimizations in submerged cultures with PH and SD should be undertaken to increase the enzymatic production from these wastes.

Endoglucanases are enzymes widely employed in different industrial fields, albeit with high production costs. Studies on new microbial sources and low-cost substrates are highly relevant, including those on agro-industrial. Current analysis evaluates peanut hull (PH) and sawdust (SD) as substrates for submerged cultures of 14 endophytic fungi isolated from grapevine (Vitis labrusca L.) cultivars Bordô and Concord. Endophytes were grown on a carboxymethylcellulose (CMC) medium and the cup plate assay showed that eight strains (belonging to genera Cochliobolus, Diaporthe, Fusarium and Phoma) had positive results: enzymatic halos ranged from 10.8±0.02 to 15.5±0.07 mm in diameter. Diaporthe sp. strains (GenBank accession codes KM362392, KM362368 and KM362378) and Fusarium culmorum KM362384 were highlighted as the most promising sources. Further, PH and SD as substrates for the fermentation of these fungi were evaluated by the cup plate assay and endoglucanase activity assay. Highest halo diameters were obtained for Diaporthe sp. KM362392: 16.1±0.01 mm (CMC), 14.5±0.01 mm (PH) and 14.7±0.03 mm (SD). The fungus also presented the highest levels of endoglucanase activity: analysis of variance revealed that CMC (3.52±0.98 μmol/min), PH (2.93±0.23 μmol/min) and SD (3.26±0.38 μmol/min) were similarly efficient as substrates. Results deepen knowledge on V. labrusca endophytes that may be endoglucanase sources, even though further optimizations in submerged cultures with PH and SD should be undertaken to increase the enzymatic production from these wastes.