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The Journal of Cell Biology Oct 2024Aureobasidium pullulans is a ubiquitous polymorphic black yeast with industrial and agricultural applications. It has recently gained attention amongst cell biologists...
Aureobasidium pullulans is a ubiquitous polymorphic black yeast with industrial and agricultural applications. It has recently gained attention amongst cell biologists for its unconventional mode of proliferation in which multinucleate yeast cells make multiple buds within a single cell cycle. Here, we combine a chemical transformation method with genome-targeted homologous recombination to yield ∼60 transformants/μg of DNA in just 3 days. This protocol is simple, inexpensive, and requires no specialized equipment. We also describe vectors with codon-optimized green and red fluorescent proteins for A. pullulans and use these tools to explore novel cell biology. Quantitative imaging of a strain expressing cytosolic and nuclear markers showed that although the nuclear number varies considerably among cells of similar volume, total nuclear volume scales with cell volume over an impressive 70-fold size range. The protocols and tools described here expand the toolkit for A. pullulans biologists and will help researchers address the many other puzzles posed by this polyextremotolerant and morphologically plastic organism.
Topics: Aureobasidium; Cell Nucleus; Genetic Vectors; Green Fluorescent Proteins; Homologous Recombination; Luminescent Proteins; Red Fluorescent Protein; Transformation, Genetic; Genetic Techniques
PubMed: 38935076
DOI: 10.1083/jcb.202402114 -
World Journal of Microbiology &... Jun 2024Liamocins, a group of high-density glycolipids, are only produced by certain strains of the yeast-like fungi in the genus Aureobasidium. Until now, few studies have...
Liamocins, a group of high-density glycolipids, are only produced by certain strains of the yeast-like fungi in the genus Aureobasidium. Until now, few studies have focused on the surfactant properties of liamocins produced from the highly diverse tropical strains of Aureobasidium. Therefore, the aims of this research were to screen the liamocin production from tropical strains of Aureobasidium spp. and to characterize their surfactant properties. A total of 41 strains of Thai Aureobasidium spp. were screened for their ability to produce liamocins, and the products were detected using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and thin-layer chromatography. Of those strains, 30 strains of Aureobasidium spp. tested were found to produce liamocins with yields ranging from 0.53 to 10.60 g/l. The nature of all crude liamocins was heterogeneous, with different compositions and ratios depending on the yeast strain. These liamocins exhibited relatively high emulsifying activity against vegetable oils tested, with an emulsification index of around 40-50%; the emulsion stability of some liamocins was up to 30 days. The obtained critical micelle concentration values were varied, with those of liamocins produced from A. pullulans, A. melanogenum and A. thailandense falling in ranges from 7.70 to 119.78, 10.73 to > 1,000, and 68.56 to > 1,000 mg/l, respectively. The emulsification activity of liamocins was higher than that of the analytical grade rhamnolipids. These compounds showed strong surface tension reduction in a sodium chloride concentration range of 2-12% (w/v), pH values between 3 and 7, and temperatures between 4 and 121 °C. This is the first report of liamocins produced by A. thailandense.
Topics: Glycolipids; Aureobasidium; Surface-Active Agents; Thailand; Chromatography, Thin Layer; Plant Oils; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Emulsifying Agents; Emulsions
PubMed: 38914906
DOI: 10.1007/s11274-024-04058-z -
Scientific Reports Jun 2024Southern Asian flowers offer honeybees a diversity of nectar. Based on its geographical origin, honey quality varies. Traditional methods are less authentic than...
Southern Asian flowers offer honeybees a diversity of nectar. Based on its geographical origin, honey quality varies. Traditional methods are less authentic than DNA-based identification. The origin of honey is determined by pollen, polyphenolic, and macro-microorganisms. In this study, amplicon sequencing targets macro-microorganisms in eDNA using the ITS1 region to explore honey's geographical location and authentication. The variety of honey samples was investigated using ITS1 with Illumina sequencing. For all four honey samples, raw sequence reads showed 979,380 raw ITS1 amplicon reads and 375 ASVs up to the phylum level. The highest total number of 202 ASVs up to phylum level identified Bali honey with 211,189 reads, followed by Banggi honey with 309,207 a total number of 111 ASVs, and Lombok represents only 63 ASVs up to phylum level with several read 458,984. Based on Shannon and Chao1, honey samples from Bali (B2) and (B3) exhibited higher diversity than honey from Lombok (B1) and green honey from Sabah (B4), while the Simpson index showed that Banggi honey (B4) had higher diversity. Honey samples had significant variance in mycobiome taxonomic composition and abundance. Zygosaccharomyces and Aspergillus were the main genera found in Lombok honey, with percentages of 68.81% and 29.76% respectively. Bali honey samples (B2 and B3) were identified as having a significant amount of the genus Aureobasidium, accounting for 40.81% and 25% of the readings, respectively. The microbiome composition of Banggi honey (B4) showed a high presence of Zygosaccharomyces 45.17% and Aureobasidium 35.24%. The ITS1 analysis effectively distinguishes between honey samples of different origins and its potential as a discriminatory tool for honey origin and authentication purposes.
Topics: Honey; Bees; Animals; Mycobiome; Asia, Southeastern; DNA, Intergenic; Fungi; Pollen; Islands; Southeast Asian People
PubMed: 38898099
DOI: 10.1038/s41598-024-64838-3 -
Biotechnology For Biofuels and... Jun 2024Non-conventional yeasts hold significant potential as biorefinery cell factories for microbial bioproduction. Currently, gene editing systems used for these yeasts rely...
BACKGROUND
Non-conventional yeasts hold significant potential as biorefinery cell factories for microbial bioproduction. Currently, gene editing systems used for these yeasts rely on antibiotic and auxotrophic selection mechanisms. However, the drawbacks of antibiotics, including high costs, environmental concerns, and the dissemination of resistance genes, make them unsuitable for large-scale industrial fermentation. For auxotrophic selection system, the engineered strains harboring auxotrophic marker genes are typically supplemented with complex nutrient-rich components instead of precisely defined synthetic media in large-scale industrial fermentations, thus lack selection pressure to ensure the stability of heterologous metabolic pathways. Therefore, it is a critical to explore alternative selection systems that can be adapted for large-scale industrial fermentation.
RESULTS
Here, a novel glucose-dependent selection system was developed in a high pullulan-producing non-conventional strain A. melanogenum P16. The system comprised a glucose-deficient chassis cell Δpfk obtained through the knockout of the phosphofructokinase gene (PFK) and a series of chromosomal integration plasmids carrying a selection marker PFK controlled by different strength promoters. Utilizing the green fluorescent protein gene (GFP) as a reporter gene, this system achieved a 100% positive rate of transformation, and the chromosomal integration numbers of GFP showed an inverse relationship with promoter strength, with a customizable copy number ranging from 2 to 54. More importantly, the chromosomal integration numbers of target genes remained stable during successive inoculation and fermentation process, facilitated simply by using glucose as a cost-effective and environmental-friendly selectable molecule to maintain a constant and rigorous screening pressure. Moreover, this glucose-dependent selection system exhibited no significant effect on cell growth and product synthesis, and the glucose-deficient related selectable marker PFK has universal application potential in non-conventional yeasts.
CONCLUSION
Here, we have developed a novel glucose-dependent selection system to achieve customizable and stable multilocus chromosomal integration of target genes. Therefore, this study presents a promising new tool for genetic manipulation and strain enhancement in non-conventional yeasts, particularly tailored for industrial fermentation applications.
PubMed: 38886802
DOI: 10.1186/s13068-024-02531-3 -
Biochemical Genetics Jun 2024Endophytic fungi associated with plants may contain undiscovered bioactive compounds. Under standard laboratory conditions, most undiscovered compounds are inactive,...
Endophytic fungi associated with plants may contain undiscovered bioactive compounds. Under standard laboratory conditions, most undiscovered compounds are inactive, whereas their production could be stimulated under different cultivation conditions. In this study, six endophytic fungi were isolated from the bark of Koelreuteria paniculata in Quancheng Park, Jinan City, Shandong Province, one of which was identified as a new subspecies of Aureobasidium pullulans, named A. pullulans KB3. Additionally, metabolomic tools were used to screen suitable media for A. pullulans KB3 fermentation, and the results showed that peptone dextrose medium (PDM) was more beneficial to culture A. pullulans KB3 for isolation of novel compounds. Sphaerolone, a polyketone compound, was initially isolated from A. pullulans KB3 via scaled up fermentation utilizing PDM. Additionally, the whole-genome DNA of A. pullulans KB3 was sequenced to facilitate compound isolation and identify the biosynthesis gene clusters (BGCs). This study reports the multi-omics (metabolome and genome) analysis of A. pullulans KB3, laying the foundation for discovering novel compounds of silent BGCs and identifying their biosynthesis pathway.
PubMed: 38877158
DOI: 10.1007/s10528-024-10866-7 -
Fungal Biology Jun 2024Volatile organic compounds (VOCs) produced by yeasts can positively affect crops, acting as antifungals or biostimulants. In this study, Aureobasidium pullulans and...
Volatile organic compounds (VOCs) produced by yeasts can positively affect crops, acting as antifungals or biostimulants. In this study, Aureobasidium pullulans and Metschnikowia pulcherrima were evaluated as potential antagonists of Trichoderma spp., common fungal pathogen in mushroom cultivation. To assess the biocontrol ability and biostimulant properties of the selected yeast species, in vitro co-culture and VOCs exposure assays were conducted. In both assays, VOCs produced by Aureobasidium spp. showed the stronger antifungal activity with a growth inhibition up to 30 %. This result was further confirmed by the higher volatilome alcohol content revealed by solid phase microextraction-gas chromatography mass spectrometry (SPME/GC-MS). Overall, Aureobasidium strains can be potentially used as biocontrol agent in Pleorotus ostreatus and Cyclocybe cylindracea mycelial growth, without affecting their development as demonstrated by VOCs exposure assay and Fourier-transform infrared spectroscopy (FT-IR). Conversely, M. pulcherrima was characterized by a lower or absent antifungal properties and by a volatilome composition rich in isobutyl acetate, an ester often recognized as plant growth promoter. As confirmed by FT-IR, Lentinula mycelia exposed to M. pulcherrima VOCs showed a higher content of proteins and lipids, suggesting an improvement of some biochemical properties. Our study emphasizes that VOCs produced by specific yeast strains are potentially powerful alternative to synthetic fungicide in the vegetative growth of mushroom-forming fungi and also able to modify their biochemical composition.
Topics: Volatile Organic Compounds; Mycelium; Agaricales; Gas Chromatography-Mass Spectrometry; Antifungal Agents; Biological Control Agents; Metschnikowia; Antibiosis; Aureobasidium; Trichoderma; Solid Phase Microextraction
PubMed: 38876538
DOI: 10.1016/j.funbio.2024.05.007 -
Fungal Biology Jun 2024Post-harvest decay of fresh agricultural produce is a major threat to food security globally. Synthetic fungicides, commonly used in practice for managing the...
Antagonistic potential of endophytic fungal isolates of tomato (Solanum lycopersicum L.) fruits against post-harvest disease-causing pathogens of tomatoes: An in vitro investigation.
Post-harvest decay of fresh agricultural produce is a major threat to food security globally. Synthetic fungicides, commonly used in practice for managing the post-harvest losses, have negative impacts on consumers' health. Studies have reported the effectiveness of fungal isolates from plants as biocontrol agents of post-harvest diseases, although this is still poorly established in tomatoes (Solanum lycopersicum L. cv. Jasmine). In this study, 800 endophytic fungi were isolated from mature green and ripe untreated and fungicide-treated tomato fruits grown in open soil and hydroponics systems. Of these, five isolates (Aureobasidium pullulans SUG4.1, Coprinellus micaceus SUG4.3, Epicoccum nigrum SGT8.6, Fusarium oxysporum HTR8.4, Preussia africana SUG3.1) showed antagonistic properties against selected post-harvest pathogens of tomatoes (Alternaria alternata, Fusarium solani, Fusarium oxysporum, Geotrichum candidum, Rhizopus stolonifera, Rhizoctonia solani), with Lactiplantibacillus plantarum as a positive control. P. africana SUG3.1 and C. micaceus SUG4.3 significantly inhibited growth of all the pathogens, with antagonistic capabilities comparable to that exhibited by L. plantarum. Furthermore, the isolates produced an array of enzymes, including among others, amylase, cellulose and protease; and were able to utilize several carbohydrates (glucose, lactose, maltose, mannitol, sucrose). In conclusion, P. africana SUG3.1 and C. micaceus SUG4.3 may complement L. plantarum as biocontrol agents against post-harvest pathogens of tomatoes.
Topics: Solanum lycopersicum; Plant Diseases; Fruit; Endophytes; Fungi; Antibiosis; Biological Control Agents; Fungicides, Industrial
PubMed: 38876537
DOI: 10.1016/j.funbio.2024.05.006 -
Genomic deletions in Aureobasidium pullulans by an AMA1 plasmid for gRNA and CRISPR/Cas9 expression.Fungal Biology and Biotechnology Jun 2024Aureobasidium pullulans is a generalist polyextremotolerant black yeast fungus. It tolerates temperatures below 0 °C or salt concentrations up to 18%, among other...
BACKGROUND
Aureobasidium pullulans is a generalist polyextremotolerant black yeast fungus. It tolerates temperatures below 0 °C or salt concentrations up to 18%, among other stresses. A. pullulans genome sequencing revealed a high potential for producing bioactive metabolites. Only few molecular tools exist to edit the genome of A. pullulans, hence it is important to make full use of its potential. Two CRISPR/Cas9 methods have been proposed for the protoplast-based transformation of A. pullulans. These methods require the integration of a marker gene into the locus of the gene to be deleted, when the deletion of this gene does not yield a selectable phenotype. We present the adaptation of a plasmid-based CRISPR/Cas9 system developed in Aspergillus niger for A. pullulans to create deletion strains.
RESULTS
The A. niger CRISPR/Cas9 plasmid led to efficient genomic deletions in A. pullulans. In this study, strains with deletions ranging from 30 to 862 bp were obtained by using an AMA1 plasmid-based genome editing strategy.
CONCLUSION
The CRISPR/Cas9 transformation system presented in this study provides new opportunities for strain engineering of A. pullulans. This system allows expression of Cas9 and antibiotic resistance while being easy to adapt. This strategy could open the path to intensive genomic engineering in A. pullulans.
PubMed: 38824542
DOI: 10.1186/s40694-024-00175-4 -
Ecotoxicology and Environmental Safety Jul 2024Abrus cantoniensis Hance (ACH) is an ancient Chinese medicine herb known for its therapeutic effects. This study investigated the potential protective effect of ACH...
Abrus cantoniensis Hance (ACH) is an ancient Chinese medicine herb known for its therapeutic effects. This study investigated the potential protective effect of ACH against carbon tetrachloride (CCl)-induced liver damage in mice. Fifty (n= 50) ICR mice were grouped into five groups. CCl was intraperitoneally injected into different mice groups: AM (CCl induced), AD (ACH-treated with 25 mg/kg), AZ (ACH-treated with 50 mg/kg), and AG (ACH-treated with100mg/kg) after every three days for a total of 31 days. The control group was denoted as AC. Additionally, groups AD, AZ, and AG received daily doses of ACH via gavage throughout the study period. According to our findings, ACH administration prominently mitigated liver pathological lesions and the increased liver index induced by CCl in mice (p < 0.05). Treatment with ACH resulted in a dose-dependent recovery of GSH-px, SOD, and CAT activities (p < 0.001). Moreover, the levels of TNF-α, MDA, and ALT showed significanlty decreasing trends with various doses of ACH (p < 0.001). Furthermore, 16 S rRNA gene sequencing demonstrated that ACH increased the abundance of beneficial genera of Comoclathris, Aureobasidium, and Kazachstania while decreased the presence of pathogenic genera such as Sporobolomyces and Filobasidium. Additionally, ACH treatment ameliorated the changes in liver metabolism due to CCl and enhanced the beneficial liver metabolites. In conclusion, ACH shows potential in protecting the liver against oxidative stress and inflammation caused by CCl exposure, possibly through its effects on gut microbiota and liver metabolism. Therefore, the use of ACH may offer an effective approach for alleviating CCl-induced liver injury.
Topics: Animals; Mice, Inbred ICR; Gastrointestinal Microbiome; Liver; Mice; Chemical and Drug Induced Liver Injury; Male; Carbon Tetrachloride; Abrus; Protective Agents; Drugs, Chinese Herbal; Oxidative Stress
PubMed: 38820876
DOI: 10.1016/j.ecoenv.2024.116495 -
Medical Mycology Case Reports Jun 2024Spontaneous mycosis caused by is documented in roach in a cyprinid-prevalent water reservoir in Czechia. Gross pathological lesions included pale gills and...
Spontaneous mycosis caused by is documented in roach in a cyprinid-prevalent water reservoir in Czechia. Gross pathological lesions included pale gills and splenomegaly, as revealed during necropsy examination. Histological examination showed extensive foci with fungal elements in the kidney. The isolated fungus was identified through phenotypic and molecular characterization, including phylogeny. This report represents the first case of infection in fish and cold-blooded vertebrates, to the best of our knowledge.
PubMed: 38799503
DOI: 10.1016/j.mmcr.2024.100652