The Trichoderma atroviride putative transcription factor Blu7 controls light responsiveness and tolerance.

BACKGROUND: Most living organisms use sunlight as a source of energy and/or information about their environment. Consequently, they have developed mechanisms to sense light quality and quantity. In the fungus Trichoderma atroviride blue-light is perceived through the Blue Light Regulator Complex, which in turn up-regulates a set of genes (blu) and down-regulates another set (bld), triggering asexual reproduction. To gain insight into this process, we characterized the blu7 gene, which encodes a protein containing a C2H2 zinc finger domain. RESULTS: Δblu7 mutants show reduced conidiation at low light fluences, which is still clear even when exposed to saturating light. For the first time we show a genome wide survey of light regulated gene expression in T. atroviride, including RNA-seq analyses of the wild type and the Δblu7 strains after brief exposure to blue-light. Our data show a reduction in the number of induced genes and an increase in down-regulated genes in the mutant. Light activates stress responses and several metabolic processes in the wild type strain that are no longer activated in the mutant. In agreement with the misregulation of metabolic processes, continuous exposure to white light strongly inhibited growth of the ∆blu7 mutant, in a carbon source dependent fashion. RNA-seq analyses under constant white light using glucose as sole carbon source revealed that localization and transport process present the opposite regulation pattern in the ∆blu7 and wild type strains. Genes related to amino acid, sugar and general transporters were enriched in the induced genes in the mutant and the repressed genes of the wild type. Peptone supplemented in the media restored growth of the ∆blu7 mutant in constant light, suggesting a role of Blu7 in the regulation of nitrogen metabolism in the presence of light. CONCLUSIONS: Blu7 appears to regulate light sensitivity in terms of induction of conidiation, and to play a major role in supporting growth under continuous exposure to light. The diminished conidiation observed in ∆blu7 mutants is likely due to misregulation of the cAMP signaling pathway and ROS production, whereas their low tolerance to continuous exposure to light indicates that Blu7 is required for adaptation.

Identification of a novel carbohydrate esterase from Bjerkandera adusta: structural and function predictions through bioinformatics analysis and molecular modeling.

A new gene from Bjerkandera adusta strain UAMH 8258 encoding a carbohydrate esterase (designated as BacesI) was isolated and expressed in Pichia pastoris. The gene had an open reading frame of 1410 bp encoding a polypeptide of 470 amino acid residues, the first 18 serving as a secretion signal peptide. Homology and phylogenetic analyses showed that BaCesI belongs to carbohydrate esterases family 4. Three-dimensional modeling of the protein and normal mode analysis revealed a breathing mode of the active site that could be relevant for esterase activity. Furthermore, the overall negative electrostatic potential of this enzyme suggests that it degrades neutral substrates and will not act on negative substrates such as peptidoglycan or p-nitrophenol derivatives. The enzyme shows a specific activity of 1.118 U mg(-1) protein on 2-naphthyl acetate. No activity was detected on p-nitrophenol derivatives as proposed from the electrostatic potential data. The deacetylation activity of the recombinant BaCesI was confirmed by measuring the release of acetic acid from several substrates, including oat xylan, shrimp shell chitin, N-acetylglucosamine, and natural substrates such as sugar cane bagasse and grass. This makes the protein very interesting for the biofuels production industry from lignocellulosic materials and for the production of chitosan from chitin.

Long-read sequencing and de novo genome assembly data of Candida parapsilosis HMC1 and Rhodotorula mucilaginosa LBMH1012, two novel isolates with antifungal resistance signatures.

Candida parapsilosis and Rhodotorula mucilaginosa are opportunistic pathogens affecting mostly immunocompromised hosts. Both species have emerged as causes of invasive candidiasis and sepsis respectively. Here we present high-quality long-read genome assemblies for a strain of C. parapsilosis isolated from human breast milk, with multiple predicted signatures consistent with Candida Drug Resistance CDR1/CDR2 and Multi Drug Resistance MDR1-type genes, also for an environmental strain of R. mucilaginosa with multiresistance to azole antifungals. The genome sequencing was performed using the R9.4.1 flowcell with the MinION Mk1B sequencer (Oxford Nanopore Technologies, Oxford, UK). The draft genome of C. parapsilosis HMC1 was assembled from 85,745 long-reads and has 13,114,208 bp in length and comprises 10 contigs making it a highly contiguous assembly. The R. mucilaginosa LBMH1012 assembly has 23,636,156 bp in length and comprises 54 contigs. The genome completeness was estimated as 94.02 % and 91.40 % respectively using BUSCO. These data may be useful to explore the genetic diversity landscape in both species, infer potential causal genes for antifungal resistance and virulence, and represent an addition to the useful sequence space on emerging fungal pathogens.

LOX1- and PLP1-dependent transcriptional reprogramming is essential for injury-induced conidiophore development in a filamentous fungus.

IMPORTANCE: In addition to being considered a biocontrol agent, the fungus Trichoderma atroviride is a relevant model for studying mechanisms of response to injury conserved in plants and animals that opens a new landscape in relation to regeneration and cell differentiation mechanisms. Here, we reveal the co-functionality of a lipoxygenase and a patatin-like phospholipase co-expressed in response to wounding in fungi. This pair of enzymes produces oxidized lipids that can function as signaling molecules or oxidative stress signals that, in ascomycetes, induce asexual development. Furthermore, we determined that both genes participate in the regulation of the synthesis of 13-HODE and the establishment of the physiological responses necessary for the formation of reproductive aerial mycelium ultimately leading to asexual development. Our results suggest an injury-induced pathway to produce oxylipins and uncovered physiological mechanisms regulated by LOX1 and PLP1 to induce conidiation, opening new hypotheses for the novo regeneration mechanisms of filamentous fungi.

Improvement and Validation of a Genomic DNA Extraction Method for Human Breastmilk.

The human milk microbiota (HMM) of healthy women can vary substantially, as demonstrated by recent advances in DNA sequencing technology. However, the method used to extract genomic DNA (gDNA) from these samples may impact the observed variations and potentially bias the microbiological reconstruction. Therefore, it is important to use a DNA extraction method that is able to effectively isolate gDNA from a diverse range of microorganisms. In this study, we improved and compared a DNA extraction method for gDNA isolation from human milk (HM) samples to commercial and standard protocols. We evaluated the extracted gDNA using spectrophotometric measurements, gel electrophoresis, and PCR amplifications to assess its quantity, quality, and amplifiability. Additionally, we tested the improved method's ability to isolate amplifiable gDNA from fungi, Gram-positive and Gram-negative bacteria to validate its potential for reconstructing microbiological profiles. The improved DNA extraction method resulted in a higher quality and quantity of the extracted gDNA compared to the commercial and standard protocols and allowed for polymerase chain reaction (PCR) amplification of the V3-V4 regions of the 16S ribosomal gene in all the samples and the ITS-1 region of the fungal 18S ribosomal gene in 95% of the samples. These results suggest that the improved DNA extraction method demonstrates better performance for gDNA extraction from complex samples such as HM.

Soil Type Influences Novel "Milpa" Isolates of Trichoderma virens and Aspergillus tubingensis That Promote Solubilization, Mineralization, and Phytoabsorption of Phosphorus in Capsicum annuum L.

The Capsicum genus has significant economic importance since it is cultivated and consumed worldwide for its flavor and pungent properties. In 2021, Mexico produced 3.3 billion tons on 45,000 hectares which yielded USD 2 billion in exports to the USA, Canada, Japan, etc. Soil type has a dramatic effect on phosphorus (P) availability for plantsdue to its ion retention.In a previous study, novel fungal isolates were shown to solubilize and mineralize P in different kinds of soils with different P retention capacities. The aim of this work was to study the effects of the mineralogy of different kinds of "milpa" soils on the germination, biomass production, and P absorption of chili plants (Capsicum annuum). The germination percentage, the germination speed index, and the mean germination time were significantly increased in the plants treated with dual inoculation. Foliar phosphorus, growth variables, and plant biomass of chili plants grown in a greenhouse were enhanced in different soil types and with different inocula. Correlation studies suggested that the most significant performance in the foliar P concentration and in the growth response of plants was achieved in Vertisol with dual inoculation of 7 × 106 mL-1 spores per chili plant, suggesting this would be an appropriate approach to enhance chili cultivation depending on the soil type. This study stresses the importance of careful analysis of the effect of the soil type in the plant-microbe interactions.

A Versatile Peroxidase from the Fungus Bjerkandera adusta Confers Abiotic Stress Tolerance in Transgenic Tobacco Plants.

White-rot fungi are efficient lignin degraders due to the secretion of lignin peroxidase, manganese peroxidase, laccase, and versatile peroxidase (VP) on decayed wood. The VP is a high-redox-potential enzyme and could be used to detoxify reactive oxygen species (ROS), which accumulate in plants during biotic and abiotic stresses. We cloned the VP gene and expressed it via the Agrobacterium transformation procedure in transgenic tobacco plants to assay their tolerance to different abiotic stress conditions. Thirty independent T2 transgenic VP lines overexpressing the fungal Bjerkandera adustaVP gene were selected on kanamycin. The VP22, VP24, and VP27 lines showed significant manganese peroxidase (MnP) activity. The highest was VP22, which showed 10.87-fold more manganese peroxidase activity than the wild-type plants and led to a 34% increase in plant height and 28% more biomass. The VP22, VP24, and VP27 lines showed enhanced tolerance to drought, 200 mM NaCl, and 400 mM sorbitol. Also, these transgenics displayed significant tolerance to methyl viologen, an active oxygen-generating compound. The present data indicate that overproducing the VP gene in plants increases significantly their biomass and the abiotic stress tolerance. The VP enzyme is an effective biotechnological tool to protect organisms against ROS. In transgenic tobacco plants, it improves drought, salt, and oxidative stress tolerance. Thus, the VP gene represents a great potential for obtaining stress-tolerant crops.

Effects on Capsicum annuum Plants Colonized with Trichoderma atroviride P. Karst Strains Genetically Modified in Taswo1, a Gene Coding for a Protein with Expansin-like Activity.

Here, we analyzed the effects on Capsicum annuum plants of Trichoderma atroviride P. Karst strains altered in the expression of SWOLLENIN (SWO1), a protein with amorphogenic activity on plant cell wall components. Strains of T. atroviride that overexpressed the Taswo1 gene were constructed as well as deletion mutants. A novel, cheap and accurate method for assessing root colonization was developed. Colonization assays showed that the Taswo1 overexpressing strains invaded the host root better than the WT, resulting in a stronger plant growth-promoting effect. The expression of plant defense marker genes for both the systemic acquired resistance and induced systemic resistance pathways was enhanced in plants inoculated with Taswo1 overexpressing strains, while inoculation with deletion mutant strains resulted in a similar level of expression to that observed upon inoculation with the wild-type strain. Response to pathogen infection was also enhanced in the plants inoculated with the Taswo1 overexpressing strains, and surprisingly, an intermediate level of protection was achieved with the mutant strains. Tolerance to abiotic stresses was also higher in plants inoculated with the Taswo1 overexpressing strains but was similar in plants inoculated with the wild-type or the mutant strains. Compatible osmolyte production in drought conditions was studied. This study may contribute to improving Trichoderma biocontrol and biofertilization abilities.

In vivo assessment and characterization of lactic acid bacteria with probiotic profile isolated from human milk powder.

INTRODUCTION: Introduction: breast milk (MH) contains nutrients and bioactive compounds for child development, including probiotic bacteria, which contribute to intestinal maturation. This benefit accompanies the individual until adulthood. There are new methods such as spray drying that give this compound a good conservation without loss of microbiota. Objective: the aim of this study was to analyze the viability of lactic acid bacteria isolated from human milk with probiotic potential after the spray drying process, as well as to evaluate the possible adhesion in the colon of mice of the Balb/C strain after feeding them powdered human milk and a commercial formula milk. Method: we isolated and identified the presence of lactic acid bacteria with possible probiotic potential in powdered human milk using the MALDI-TOF MS technique. Powdered human milk and a commercial formula milk were fed to mice of the Bald/C strain for 14 weeks. Glucose level and weight were measured in the mice. The feces were collected to verify the presence of lactic bacteria. The mice were sacrificed and their intestines were weighed, isolating the lactic acid bacteria both from the intestines and from the feces. The strains isolated from mice fed human milk were evaluated for their probiotic potential, analyzing their ability to inhibit pathogens, resistance to pH, temperature, adhesion, and hydrophobicity. Results: the presence of Lactobacillus fermentum LH01, Lactobacillus rhamnosus LH02, Lactobacullis reuteri LH03, and Lactobacillus plantarum LH05 in powdered human milk was identified. All strains showed a possible probiotic profile due to the ability of bacteria to resist low pH, bile salts, and exposure to gastric enzymes, as well as their hydrophobicity and self-aggregation capacity, and their failure to show hemagglutination or hemolysis activity in a culture medium rich in erythrocytes. We observed that the consumption of powdered human milk prevented weight gain and constipation in mice. Conclusions: after spray drying, strains with possible probiotic potential may be preserved in human milk. The consumption of powdered human milk with probiotic bacteria prevents constipation and weight gain in mice, when compared to those fed a commercial formula milk.

INTRODUCCIÓN: Introducción: la leche materna (HM) contiene los nutrientes y compuestos bioactivos necesarios para el desarrollo infantil, incluidas bacterias probióticas, que contribuyen a la maduración intestinal. Objetivo: el objetivo de este estudio fue analizar la viabilidad de las bacterias acidolácticas aisladas de la leche humana con potencial probiótico, después del proceso de secado, así como evaluar su posible adhesión en el colón de ratones (BAlb/C) alimentados con leche humana en polvo y leche de una fórmula comercial. Método: se aislaron e identificaron mediante la técnica de Maldi-Tof-MS las bacterias acidolácticas con posible potencial probiótico en la leche humana en polvo. Se alimentó con leche humana en polvo y leche de una fórmula comercial a ratones de la cepa Bald/C durante 14 semanas. Se midieron el nivel de glucosa y el peso. Las heces se recolectaron para verificar la presencia de bacterias lácticas. Los ratones se sacrificaron y se pesaron los intestinos, aislando las bacterias lácticas tanto de los intestinos como de las heces. En las cepas aisladas de la leche humana se evaluó el potencial probiótico analizando su capacidad para inhibir patógenos, resistir distintos pH y temperaturas, adherirse y mostrar hidrofobicidad. Resultados: se identificó la presencia de Lactobacillus fermentum LH01, Lactobacillus rhamnosus LH02, Lactobacullis reuteri LH03 y L. plantarum LH05 en la leche humana en polvo. Todas las cepas mostraron resistencia a los pH bajos, a las sales biliares y a la exposición a enzimas gástricas, así como una buena hidrofobicidad y capacidad de autoagregación. Además, no presentaron actividad de hemaglutinación o hemólisis en un medio de cultivo rico en eritrocitos. Observamos que el consumo de leche humana en polvo evita en los ratones el aumento de peso y el estreñimiento. Conclusiones: después del secado por aspersión, las cepas con posible potencial probiótico pueden conservarse en la leche materna. El consumo de leche humana en polvo con bacterias probióticas evita el estreñimiento y el aumento de peso en los ratones, en comparación con los alimentados con leche de una formula comercial.

Characterization of lignocellulolytic activities from fungi isolated from the deep-sea sponge Stelletta normani.

Extreme habitats have usually been regarded as a source of microorganisms that possess robust proteins that help enable them to survive in such harsh conditions. The deep sea can be considered an extreme habitat due to low temperatures (<5°C) and high pressure, however marine sponges survive in these habitats. While bacteria derived from deep-sea marine sponges have been studied, much less information is available on fungal biodiversity associated with these sponges. Following screening of fourteen fungi isolated from the deep-sea sponge Stelletta normani sampled at a depth of 751 metres, three halotolerant strains (TS2, TS11 and TS12) were identified which displayed high CMCase and xylanase activities. Molecular based taxonomic approaches identified these strains as Cadophora sp. TS2, Emericellopsis sp. TS11 and Pseudogymnoascus sp. TS 12. These three fungi displayed psychrotolerance and halotolerant growth on CMC and xylan as sole carbon sources, with optimal growth rates at 20°C. They produced CMCase and xylanase activities, which displayed optimal temperature and pH values of between 50-70°C and pH 5-8 respectively, together with good thermostability and halotolerance. In solid-state fermentations TS2, TS11 and TS12 produced CMCases, xylanases and peroxidase/phenol oxidases when grown on corn stover and wheat straw. This is the first time that CMCase, xylanase and peroxidase/phenol oxidase activities have been reported in these three fungal genera isolated from a marine sponge. Given the biochemical characteristics of these ligninolytic enzymes it is likely that they may prove useful in future biomass conversion strategies involving lignocellulosic materials.

In vivo assessment and characterization of lactic acid bacteria with probiotic profile isolated from human milk powder / Evaluación y caracterización in vivo de bacterias acidolácticas con perfil probiótico aisladas a partir de leche materna en polvo

INTRODUCTION: breast milk (MH) contains nutrients and bioactive compounds for child development, including probiotic bacteria, which contribute to intestinal maturation. This benefit accompanies the individual until adulthood. There are new methods such as spray drying that give this compound a good conservation without loss of microbiota. OBJECTIVE: the aim of this study was to analyze the viability of lactic acid bacteria isolated from human milk with probiotic potential after the spray drying process, as well as to evaluate the possible adhesion in the colon of mice of the Balb/C strain after feeding them powdered human milk and a commercial formula milk. METHOD: we isolated and identified the presence of lactic acid bacteria with possible probiotic potential in powdered human milk using the MALDI-TOF MS technique. Powdered human milk and a commercial formula milk were fed to mice of the Bald/C strain for 14 weeks. Glucose level and weight were measured in the mice. The feces were collected to verify the presence of lactic bacteria. The mice were sacrificed and their intestines were weighed, isolating the lactic acid bacteria both from the intestines and from the feces. The strains isolated from mice fed human milk were evaluated for their probiotic potential, analyzing their ability to inhibit pathogens, resistance to pH, temperature, adhesion, and hydrophobicity. RESULTS: the presence of Lactobacillus fermentum LH01, Lactobacillus rhamnosus LH02, Lactobacullis reuteri LH03, and Lactobacillus plantarum LH05 in powdered human milk was identified. All strains showed a possible probiotic profile due to the ability of bacteria to resist low pH, bile salts, and exposure to gastric enzymes, as well as their hydrophobicity and self-aggregation capacity, and their failure to show hemagglutination or hemolysis activity in a culture medium rich in erythrocytes. We observed that the consumption of powdered human milk prevented weight gain and constipation in mice. CONCLUSIONS: after spray drying, strains with possible probiotic potential may be preserved in human milk. The consumption of powdered human milk with probiotic bacteria prevents constipation and weight gain in mice, when compared to those fed a commercial formula milk

INTRODUCCIÓN: la leche materna (HM) contiene los nutrientes y compuestos bioactivos necesarios para el desarrollo infantil, incluidas bacterias probióticas, que contribuyen a la maduración intestinal. OBJETIVO: el objetivo de este estudio fue analizar la viabilidad de las bacterias acidolácticas aisladas de la leche humana con potencial probiótico, después del proceso de secado, así como evaluar su posible adhesión en el colón de ratones (BAlb/C) alimentados con leche humana en polvo y leche de una fórmula comercial. MÉTODO: se aislaron e identificaron mediante la técnica de Maldi-Tof-MS las bacterias acidolácticas con posible potencial probiótico en la leche humana en polvo. Se alimentó con leche humana en polvo y leche de una fórmula comercial a ratones de la cepa Bald/C durante 14 semanas. Se midieron el nivel de glucosa y el peso. Las heces se recolectaron para verificar la presencia de bacterias lácticas. Los ratones se sacrificaron y se pesaron los intestinos, aislando las bacterias lácticas tanto de los intestinos como de las heces. En las cepas aisladas de la leche humana se evaluó el potencial probiótico analizando su capacidad para inhibir patógenos, resistir distintos pH y temperaturas, adherirse y mostrar hidrofobicidad. RESULTADOS: se identificó la presencia de Lactobacillus fermentum LH01, Lactobacillus rhamnosus LH02, Lactobacullis reuteri LH03 y L. plantarum LH05 en la leche humana en polvo. Todas las cepas mostraron resistencia a los pH bajos, a las sales biliares y a la exposición a enzimas gástricas, así como una buena hidrofobicidad y capacidad de autoagregación. Además, no presentaron actividad de hemaglutinación o hemólisis en un medio de cultivo rico en eritrocitos. Observamos que el consumo de leche humana en polvo evita en los ratones el aumento de peso y el estreñimiento. CONCLUSIONES: después del secado por aspersión, las cepas con posible potencial probiótico pueden conservarse en la leche materna. El consumo de leche humana en polvo con bacterias probióticas evita el estreñimiento y el aumento de peso en los ratones, en comparación con los alimentados con leche de una formula comercial

Xenobiotic Compounds Degradation by Heterologous Expression of a Trametes sanguineus Laccase in Trichoderma atroviride.

Fungal laccases are enzymes that have been studied because of their ability to decolorize and detoxify effluents; they are also used in paper bleaching, synthesis of polymers, bioremediation, etc. In this work we were able to express a laccase from Trametes (Pycnoporus) sanguineus in the filamentous fungus Trichoderma atroviride. For this purpose, a transformation vector was designed to integrate the gene of interest in an intergenic locus near the blu17 terminator region. Although monosporic selection was still necessary, stable integration at the desired locus was achieved. The native signal peptide from T. sanguineus laccase was successful to secrete the recombinant protein into the culture medium. The purified, heterologously expressed laccase maintained similar properties to those observed in the native enzyme (Km and kcat and kcat/km values for ABTS, thermostability, substrate range, pH optimum, etc). To determine the bioremediation potential of this modified strain, the laccase-overexpressing Trichoderma strain was used to remove xenobiotic compounds. Phenolic compounds present in industrial wastewater and bisphenol A (an endocrine disruptor) from the culture medium were more efficiently removed by this modified strain than with the wild type. In addition, the heterologously expressed laccase was able to decolorize different dyes as well as remove benzo[α]pyrene and phenanthrene in vitro, showing its potential for xenobiotic compound degradation.

Characterization of lignocellulolytic activities from a moderate halophile strain of Aspergillus caesiellus isolated from a sugarcane bagasse fermentation.

A moderate halophile and thermotolerant fungal strain was isolated from a sugarcane bagasse fermentation in the presence of 2 M NaCl that was set in the laboratory. This strain was identified by polyphasic criteria as Aspergillus caesiellus. The fungus showed an optimal growth rate in media containing 1 M NaCl at 28°C and could grow in media added with up to 2 M NaCl. This strain was able to grow at 37 and 42°C, with or without NaCl. A. caesiellus H1 produced cellulases, xylanases, manganese peroxidase (MnP) and esterases. No laccase activity was detected in the conditions we tested. The cellulase activity was thermostable, halostable, and no differential expression of cellulases was observed in media with different salt concentrations. However, differential band patterns for cellulase and xylanase activities were detected in zymograms when the fungus was grown in different lignocellulosic substrates such as wheat straw, maize stover, agave fibres, sugarcane bagasse and sawdust. Optimal temperature and pH were similar to other cellulases previously described. These results support the potential of this fungus to degrade lignocellulosic materials and its possible use in biotechnological applications.

Characterization of cellulolytic activities of Bjerkandera adusta and Pycnoporus sanguineus on solid wheat straw medium / Caracterización de las actividades celulolíticas de Bjerkandera adusta y Pycnoporus sanguineus en un medio sólido de paja de trigo

Cellulolytic properties of two white rot fungi, Bjerkandera adusta and Pycnoporus sanguineus, cultivated on wheat straw agar medium, were characterized and compared. Optimal growing parameters for maximum enzyme production for both fungi were wheat straw medium pH 5 and 28ºC. B. adusta showed, on the 6th day of culture, carboxymethylcellulose (CMC)ase activity levels 1.6 times higher than maximal P. sanguineus activity, achieved on the 8th day. B. adusta supernatants also displayed higher activity levels towards xylan (3.6-fold) compared to those of P. sanguineus. However, enzymes from P. sanguineus were more robust resisting one hour incubation at high temperatures (up to 80ºC), and exhibiting activity and stability in pH range from 2 to 8. Cellulolytic activities, with molecular masses ranging from 25 to 90 kDa, from the two species were detected in zymograms.