Nuclear hormone receptors promote gut and glia detoxifying enzyme induction and protect C. elegans from the mold P. brevicompactum

Animals encounter microorganisms in their habitats, adapting physiology and behavior accordingly. The nematode Caenorhabditis elegans is found in microbe-rich environments; however, its responses to fungi are not extensively studied. Here we describe interactions of C. elegans and Penicillium brevicompactum, an ecologically-relevant mold. Transcriptome studies reveal that co-culture upregulates stress-response genes, including xenobiotic metabolizing enzymes (XMEs), in C. elegans intestine and AMsh glial cells. The nuclear hormone receptors (NHR) NHR-45 and NHR-156 are key induction regulators, and mutants that cannot induce XMEs in the intestine when exposed to P. brevicompactum experience mitochondrial stress and exhibit developmental defects. Different C. elegans wild isolates harbor sequence polymorphisms in nhr-156, resulting in phenotypic diversity in AMsh glia responses to microbe exposure. We propose that P. brevicompactum mitochondria-targeting mycotoxins are deactivated by intestinal detoxification, allowing tolerance to moldy environments. Our studies support the idea that C. elegans NHR gene expansion/diversification underlies adaptation to microbial environments.

Comparative Study for the Production of Mycophenolic Acid using Penicillium brevicompactum in Batch, Fed-batch and Continuous Fermentation Process

Mycophenolic acid (MPA) is, due to its immunosuppressive and biological activities, a potential compound. It is the secondary metabolite produced in submerged cultivation by the microfungus Penicillium brevicompactum. Batch, fed-batch, and continuous mode of cultivation for mycophenolic acid production were performed and compared in the current work. To increase productivity, mycophenolic acid production was studied in batch, fed-batch, and continuous bioreactors. These experiments were conducted with a 2.5 L working volume in a 3.7 L continuous stirred tank bioreactor. In all cases, operating conditions such as temperature, pH, agitation, and aeration, 28 °C, 5.5, 200 rpm, and 2 vvm, respectively, were the same. In fed-batch fermentation, the MPA concentration obtained was 1.91 g/L higher than the value obtained in batch culture, 1.55 g/L, while in continuous fermentation, 1.67 g/L was obtained. The mycophenolic acid productivity obtained in the continuous fermentation process was 0.025 g/L/h, which was maximum MPA productivity, compared to 0.007 g/L/h in the fed-batch fermentation process and 0.006 g/L/h in the batch fermentation process. The impact of substrate inhibition on the product formation can effectively bring down by continuous fermentation processes. The MPA productivity was increased in continuous fermentation relative to batch and fed-batch processing. The finding indicates that continuous culture of Penicillium brevicompactum is a promising strategy for the synthesis of mycophenolic acid.

Revealing the hidden diversity of marine fungi in Portugal with the description of two novel species, Neoascochyta fuci sp. nov. and Paraconiothyrium salinum sp. nov.

Fungi are ubiquitous organisms with a wide distribution in almost all ecosystems, including marine environments. Coastal and estuarine ecosystems remain poorly unexplored as fungal habitats, potentially harbouring a hidden diversity with important ecological roles. During an extensive survey of marine fungi in coastal and estuarine Portuguese environments, a collection of 612 isolates was obtained from water, algae, sponges and driftwood. From these, 282 representative isolates were selected through microsatellite-primed PCR (MSP-PCR) fingerprinting analysis, which were identified based on DNA sequence data. The collection yielded 117 taxa from 38 distinct genera, which were identified using DNA sequence analysis. Overall, fungal community composition varied with host/substrate, but the most abundant taxa in the collection were Cladosporium cladosporioides, Penicillium terrigenum, Penicillium brevicompactum and Fusarium equiseti/incarnatum complex. The occurrence of a high fungal diversity harbouring novel species was disclosed. Through a multilocus phylogeny based on ITS, tub2 and tef1-α sequences, in conjunction with morphological and physiological data, we propose Neoascochyta fuci sp. nov. and Paraconiothyrium salinum sp. nov.

Interacción de hongos micorrízicos arbusculares y una cepa fosfato solubilizadora en Canavalia ensiformis (Fabaceae)

Antecedentes: Canavalia ensiformis es una leguminosa forrajera de origen tropical ampliamente utilizada como abono verde. El uso de hongos micorrízicos y solubilizadores de fósforo es una alternativa agronómicamente viable y sustentable aplicada en cultivos de importancia económica. Hipótesis: La interacción de hongos micorrízicos arbusculares y solubilizadores de fósforo favorecerá la colonización micorrízica, la disponibilidad de fósforo y el crecimiento de las plantas de C. ensiformis. Métodos: Este estudio se realizó de marzo 2018-agosto 2019 en un invernadero con a planta cobertera C. ensiformis, un inóculo micorrízico y Penicillium brevicompactum, todas las posibles combinaciones con tres repeticiones en tres ciclos. Se evalúo la altura, número de hojas y nódulos por planta. Se tomaron muestras de raíces y suelo para determinar colonización micorrízica y P soluble. Los datos fueron analizados mediante ANOVA Factorial y test de Tukey (α=0.05). Resultados: En los tres ciclos, la micorrización fue significativamente mayor en las plantas inoculadas con la interacción HMA+HSF (Tukey < 0.05). Esta interacción favoreció un incremento de 3.07 mg/Kg de P soluble en el suelo. Los tratamientos de HSF y HMA+HSF incrementaron significativamente las variables de crecimiento de las plantas (altura y número de hojas) (p < 0.05). El número de nódulos osciló entre 46-76 y se detectó un efecto significativo del factor HMA (p < 0.05) y del HSF (p < 0.05). Conclusiones: La aplicación de las interacciones de HMA y HSF aumentó la colonización micorrízica, la disponibilidad de fósforo en el suelo y el crecimiento de las plantas de C. ensiformis.

Bacterial and mold resistance of selected tropical wood species

The biological resistance of 21 tropical wood species against bacteria and molds was studied. The gram-positive bacterium Staphylococcus aureus and the gram-negative bacterium Escherichia coli had none or negligible activity on surfaces of zebrano and maçaranduba (up to 1 ×106 CFU/mL), and they had negligible or medium activity on surfaces of macassar ebony, ovengol, santos rosewood, and iroko (from 1 ×106 up to 1 ×107 CFU/mL). These bacteria had high activity on surfaces of okoumé, tineo, doussié, makoré, and both reference woods, beech and Scots pine (usually over 1 ×107 CFU/mL). The mold growth activity (MGA) of Aspergillus niger and Penicillium brevicompactum was minimal on surfaces of ipé, yellow balau, macassar ebony, doussié, bubinga, and merbau, but it was strong on surfaces of okoumé, cerejeira, ovengol, wengé, sapelli, and both reference woods. When comparing individual biological tests of (a) bacterial and mold but also (b) bacterial, mold and rot with decaying fungi C. puteana and T. versicolor, no significant relationships were found. These results confirm that the bio-durability of woods is influenced not only by their molecular structure, but also by the attacking biological pest group.