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Journal of Fungi (Basel, Switzerland) May 2023One hundred twenty-five yeast strains isolated from table grapes and apples were evaluated for the control of in vitro and in vivo. Ten strains were selected for their...
One hundred twenty-five yeast strains isolated from table grapes and apples were evaluated for the control of in vitro and in vivo. Ten strains were selected for their ability to inhibit mycelial growth of in vitro. In the in vivo assays, these yeasts were tested at 20 °C on 'Thompson Seedless' berries for 7 days; only three were selected (m11, me99 and ca80) because they significantly reduced the incidence of gray mold. These three yeast strains were then evaluated at different concentrations (1 × 10, 1 × 10 and 1 × 10 cells mL) on 'Thompson Seedless' grape berries at 20 °C. The strains m11, me99 and ca80 reduced the incidence of to 11.9, 26.1 and 32.1%, respectively, when the berries were submerged in a yeast suspension at a concentration of 1 × 10 cells mL 24 h before inoculation with . The most favorable pH for antifungal activity was 4.6 in the three isolates. The three yeast strains secreted the hydrolytic enzymes chitinase and β-1-glucanase, and two strains (me99 and ca80) produced siderophores. The three yeast strains exhibited low oxidative stress tolerance and only strain m11 had the ability to produce biofilms. The strains were identified using 5.8S-ITS rDNA PCR-RFLP and correspond to the (m11) and (me99 and ca80) species.
PubMed: 37233268
DOI: 10.3390/jof9050557 -
Microbiology Resource Announcements May 2023The black-yeast-like is discussed as a versatile cell factory for many biotechnological applications. This article describes the 25.05-Mb draft genome sequence of...
The black-yeast-like is discussed as a versatile cell factory for many biotechnological applications. This article describes the 25.05-Mb draft genome sequence of Aureobasidium pullulans NRRL 62031, which was isolated in Thailand. The genome sequence provides evidence for a plethora of synthesis pathways for valuable secondary metabolites.
PubMed: 37039700
DOI: 10.1128/mra.00458-22 -
Frontiers in Plant Science 2023The use of biocontrol agents (BCAs) represents a promising alternative to conventional methods for the management of gray mold in vineyards during the berry ripening...
The use of biocontrol agents (BCAs) represents a promising alternative to conventional methods for the management of gray mold in vineyards during the berry ripening stage. The main advantages of BCAs are the short preharvest interval and lack of chemical fungicide residues in wine. In this study, eight commercial BCAs (based on different or species and strains, , , and ) and a reference fungicide (boscalid) were applied to a vineyard during berry ripening over three seasons to evaluate the dynamics over time in terms of their relative efficacies in gray mold control. At 1-13 days after application of BCAs to the berry surfaces in field conditions, the berries were collected and artificially inoculated with conidia of under controlled laboratory conditions, and gray mold severity was observed after 7 days of incubation. Significant differences were observed in gray mold severity among years, according to the number of days the BCAs grew on the berry surface before inoculation, and the season by day interaction (altogether accounting for >80% of the experimental variance). The variability in BCA efficacy was closely related to the environmental conditions at the time of application and in the following days. Overall, the BCA efficacy increased with the degree days accumulated between BCA application in the vineyard and inoculation in the dry (no rain) periods (r = 0.914, P = 0.001). Rainfall and the associated drop in temperature caused a relevant reduction of BCA efficacy. These results demonstrate that BCAs are an effective alternative to conventional chemicals for the preharvest control of gray mold in vineyards. However, environmental conditions can considerably affect the BCA efficacy.
PubMed: 36993848
DOI: 10.3389/fpls.2023.1154370 -
Polymers Mar 2023Discoloration of wood coatings due to fungal growth negatively affects the aesthetic properties of the coatings, and new ways to control fungal growth on coatings are...
Discoloration of wood coatings due to fungal growth negatively affects the aesthetic properties of the coatings, and new ways to control fungal growth on coatings are needed. For this reason, silver nanoparticles (AgNPs) have been incorporated in acrylic latexes as antifungal agents. Using miniemulsion polymerization, latexes were prepared with two types of initiators (hydrophilic and hydrophobic) to assess the influence of the initiator type on AgNPs dispersion, both within the latex particles and the dry film. In addition, the impact of NP dispersion on resistance to black-stain fungi () was also evaluated. Inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis indicates that acrylic latexes prepared with azobisisobutyronitrile (AIBN) as the initiator contain more AgNPs than those prepared with potassium persulfate (KPS). Cryo-TEM and SEM analyses show that the distribution of the AgNPs within the polymer particles is influenced by the nature of the initiator. When AIBN, a hydrophobic initiator, is used, the AgNPs appear to be closer to the surface of the polymer particles and more evenly distributed. However, the antifungal efficiency of the AgNPs-embedded latexes against is found to be higher when KPS is used, despite this initiator leading to a smaller amount of incorporated AgNPs and a less uniform dispersion of the nanoparticles.
PubMed: 36987366
DOI: 10.3390/polym15061586 -
Polymers Mar 2023Pullulan is a biodegradable, renewable, and environmentally friendly hydrogel biopolymer, with potential uses in food, medicine, and cosmetics. New endophytic...
Pullulan is a biodegradable, renewable, and environmentally friendly hydrogel biopolymer, with potential uses in food, medicine, and cosmetics. New endophytic (accession number; OP924554) was used for the biosynthesis of pullulan. Innovatively, the fermentation process was optimized using both Taguchi's approach and the decision tree learning algorithm for the determination of important variables for pullulan biosynthesis. The relative importance of the seven tested variables that were obtained by Taguchi and the decision tree model was accurate and followed each other's, confirming the accuracy of the experimental design. The decision tree model was more economical by reducing the quantity of medium sucrose content by 33% without a negative reduction in the biosynthesis of pullulan. The optimum nutritional conditions (g/L) were sucrose (60 or 40), KHPO (6.0), NaCl (1.5), MgSO (0.3), and yeast extract (1.0) at pH 5.5, and short incubation time (48 h), yielding 7.23% pullulan. The spectroscopic characterization (FT-IR and H-NMR spectroscopy) confirmed the structure of the obtained pullulan. This is the first report on using Taguchi and the decision tree for pullulan production by a new endophyte. Further research is encouraged for additional studies on using artificial intelligence to maximize fermentation conditions.
PubMed: 36987200
DOI: 10.3390/polym15061419 -
Molecules (Basel, Switzerland) Mar 2023Pullulan is a linear exopolysaccharide, produced in the fermentation media of , with a variety of applications in the food and pharmaceutical industries. Pullulan...
Pullulan is a linear exopolysaccharide, produced in the fermentation media of , with a variety of applications in the food and pharmaceutical industries. Pullulan derivatives have growing potential for biomedical applications, but the high cost of pullulan biofabrication currently restricts its commercial use. Better control over pullulan yield, molecular weight and melanin production by altering fermentation conditions could improve the economics. In this study, the effects of sugar and mineral salt stresses on the pullulan production of ATCC 42023 were examined in batch processes. The chemical structure of the recovered pullulan was characterized by FTIR and NMR spectroscopy, and the molecular weight distribution was obtained via SEC. Pullulan yield and melanin production varied when the conditions were adjusted, and pullulans with different molar masses were obtained. Higher-yield pullulan production and a lower polydispersity index were observed when CuSO was added to the fermentation in comparison with the control and with the addition of sugars and other salts. Biofabrication of pullulan under stress conditions is a promising strategy to enhance biopolymer yield and to obtain pullulan with a targeted molecular weight.
Topics: Salts; Sugars; Melanins; Ascomycota; Fermentation; Minerals
PubMed: 36985449
DOI: 10.3390/molecules28062478 -
Journal of Fungi (Basel, Switzerland) Feb 2023Flax ( L.) is attacked by numerous devastating fungal pathogens, including , , and (). The effective control of flax diseases follows the paradigm of extensive...
Flax ( L.) is attacked by numerous devastating fungal pathogens, including , , and (). The effective control of flax diseases follows the paradigm of extensive molecular research on pathogenicity. However, such studies require quality genome sequences of the studied organisms. This article reports on the approaches to assembling a high-quality fungal genome from the Oxford Nanopore Technologies data. We sequenced the genomes of , , and () and received different volumes of sequencing data: 1.7 Gb, 3.9 Gb, and 11.1 Gb, respectively. To obtain the optimal genome sequences, we studied the effect of input data quality and genome coverage on assembly statistics and tested the performance of different assembling and polishing software. For , the most contiguous and complete assembly was obtained by the Flye assembler and the Homopolish polisher. The genome coverage had more effect than data quality on assembly statistics, likely due to the relatively low amount of sequencing data obtained for . The final assembly was 53.4 Mb long and 96.4% complete (according to the glomerellales_odb10 BUSCO dataset), consisted of 42 contigs, and had an N50 of 4.4 Mb. For and (), the best assemblies were produced by Canu-Medaka and Canu-Homopolish, respectively. The final assembly of had a length of 29.5 Mb, 99.4% completeness (dothideomycetes_odb10), an N50 of 2.4 Mb and consisted of 32 contigs. () assembly was 44.1 Mb long, 97.8% complete (hypocreales_odb10), consisted of 54 contigs, and had an N50 of 4.4 Mb. The obtained results can serve as a guideline for assembling a de novo genome of a fungus. In addition, our data can be used in genomic studies of fungal pathogens or plant-pathogen interactions and assist in the management of flax diseases.
PubMed: 36983469
DOI: 10.3390/jof9030301 -
Vaccine Apr 2023A potential risk associated with vaccines for COVID-19 is antibody-dependent disease enhancement (ADE) in which vaccine induced antibody mediated immune responses may...
A potential risk associated with vaccines for COVID-19 is antibody-dependent disease enhancement (ADE) in which vaccine induced antibody mediated immune responses may lead to enhanced SARS CoV- 2 acquisition or increased disease severity. Though ADE has not been clinically demonstrated with any of the COVID-19 vaccines so far, when neutralizing antibodies are suboptimal, the severity of COVID-19 has been reported to be greater. ADE is presumed to occur via abnormal macrophages induced by the vaccine based immune response by antibody-mediated virus uptake into Fc gamma receptor IIa (FcγRIIa) or by the formation of Fc-mediated excessive antibody effector functions. Beta-glucans which are naturally occurring polysaccharides known for unique immunomodulation by capability to interact with macrophages, eliciting a specific beneficial immune-response and enhancing all arms of the immune system, importantly without over-activation are suggested as safer nutritional supplement-based vaccine adjuvants for COVID-19.
Topics: Humans; Antibodies, Neutralizing; Antibodies, Viral; beta-Glucans; COVID-19; COVID-19 Vaccines; Immunoglobulin Fc Fragments; SARS-CoV-2; Vaccination
PubMed: 36906407
DOI: 10.1016/j.vaccine.2023.03.005 -
Biomedicines Feb 2023β-glucan, a plant polysaccharide, mainly exists in plant cell walls of oats, barley, and wheat. It is attracting attention due to its high potential for use as...
β-glucan, a plant polysaccharide, mainly exists in plant cell walls of oats, barley, and wheat. It is attracting attention due to its high potential for use as functional foods and pharmaceuticals. We have previously reported that low-molecular-weight -fermented β-D-glucan (LMW-AP-FBG) could inhibit inflammatory responses by inhibiting mitogen-activated protein kinases and nuclear factor-κB signaling pathways. Bases on previous results, the objective of the present study was to investigate the therapeutic potential of LMW-AP-FBG in BALB/c mice intracutaneously transplanted with CT-26 colon cancer cells onto their backs. Daily intraperitoneal injections of LMW-AP-FBG (5 mg/kg) for two weeks significantly suppressed tumor growth in mice bearing CT-26 tumors by reducing tumor proliferation and inducing apoptosis as compared to phosphate buffer-treated control mice. In addition, LMW-AP-FBG treatment reduced the viability of CT-26 cells in a dose-dependent manner by inducing apoptosis with loss of mitochondrial transmembrane potential and increased activated caspases. Taken together, LMW-AP-FBG exhibits anticancer properties both in vivo and in vitro.
PubMed: 36831065
DOI: 10.3390/biomedicines11020529 -
Food Technology and Biotechnology Dec 2022Wine yeasts are a heterogeneous microbial group with high enzymatic potential that makes them a useful tool in winemaking. With a better understanding of their...
RESEARCH BACKGROUND
Wine yeasts are a heterogeneous microbial group with high enzymatic potential that makes them a useful tool in winemaking. With a better understanding of their oenological properties, selection procedures can be optimised to obtain more efficient strains. The present study aims to isolate and select yeasts from wine grape surface by studying their production of enzymes that hydrolyse plant cell wall polymers and by linking them to different technological parameters and antioxidant activity of wines.
EXPERIMENTAL APPROACH
Yeasts that are able to produce carbohydrolases and related enzymes of oenological importance were firstly selected on plates and subsequently identified. Then, a secondary selection of yeasts was carried out according to technological effects of their extracellular enzyme extracts on short macerations. In this way, the colour extraction, total polyphenol content, clarification, filterability and antioxidant activity were studied. This approach makes it possible to correlate the microorganism capacity to produce cell wall-depolymerizing enzymes with their technological effects.
RESULTS AND CONCLUSIONS
From 366 isolates, 96 strains (26.2%) showed at least one of the polysaccharidase activities and 55 strains (57.3%) of them exhibited activities of multiple enzymes that degrade plant cell wall polymers. Sixteen strains were selected and identified as , , and . Pectinolytic enzymes had the highest hydrolytic activity. had a broader enzyme blend and higher activity, dominated by pectinases and followed by xylanases and cellulases. Moreover, the m7-2 strain produced high amounts of polysaccharidase and this was strain-dependent. Strains that produced enzyme extracts with a wide range of activities that were also the highest, also had the best chromatic and technological properties. Cluster analysis confirmed that R-22, m11-2, m86-1 and m86-2 and m7-2 could be correlated with a better effect on filterability, clarification and extraction of bioactive compounds, encouraging future studies regarding their application in winemaking.
NOVELTY AND SCIENTIFIC CONTRIBUTION
The study of yeast multi-enzymatic systems impacting the grape maceration process enables a proper selection criterion for wine yeasts to improve colour extraction, technological parameters and antioxidant activity of Malbec wine. This work shows that and have a high enzymatic potential for oenological purposes.
PubMed: 36816877
DOI: 10.17113/ftb.60.04.22.7777