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Applied Microbiology and Biotechnology Jan 2024Honeybee (Apis mellifera) is an important agricultural pollinator and a model for sociality. In this study, a deep knowledge on yeast community characterizing the...
Honeybee (Apis mellifera) is an important agricultural pollinator and a model for sociality. In this study, a deep knowledge on yeast community characterizing the honeybees' environmental was carried out. For this, a total of 93 samples were collected: flowers as food sources, bee gut mycobiota, and bee products (bee pollen, bee bread, propolis), and processed using culture-dependent techniques and a molecular approach for identification. The occurrence of yeast populations was quantitatively similar among flowers, bee gut mycobiota, and bee products. Overall, 27 genera and 51 species were identified. Basidiomycetes genera were predominant in the flowers while the yeast genera detected in all environments were Aureobasidium, Filobasidium, Meyerozyma, and Metschnikowia. Fermenting species belonging to the genera Debaryomyces, Saccharomyces, Starmerella, Pichia, and Lachancea occurred mainly in the gut, while most of the identified species of bee products were not found in the gut mycobiota. Five yeast species, Meyerozyma guilliermondii, Debaryomyces hansenii, Hanseniaspora uvarum, Hanseniaspora guilliermondii, and Starmerella roseus, were present in both summer and winter, thus indicating them as stable components of bee mycobiota. These findings can help understand the yeast community as a component of the bee gut microbiota and its relationship with related environments, since mycobiota characterization was still less unexplored. In addition, the gut microbiota, affecting the nutrition, endocrine signaling, immune function, and pathogen resistance of honeybees, represents a useful tool for its health evaluation and could be a possible source of functional yeasts. KEY POINTS: • The stable yeast populations are represented by M. guilliermondii, D. hansenii, H. uvarum, H. guilliermondii, and S. roseus. • A. pullulans was the most abondance yeast detective in the flowers and honeybee guts. • Aureobasidium, Meyerozyma, Pichia, and Hanseniaspora are the main genera resident in gut tract.
Topics: Bees; Animals; Yeasts; Ascomycota; Pichia; Gastrointestinal Microbiome; Flowers
PubMed: 38276993
DOI: 10.1007/s00253-023-12942-1 -
Frontiers in Microbiology 2023The organoleptic profile and quality of wine are affected by the presence of different non-s species and strains. Therefore, the identification and characterization of...
The organoleptic profile and quality of wine are affected by the presence of different non-s species and strains. Therefore, the identification and characterization of non-s yeasts are the first step to understand their function, and to develop a better strain selection program for winemaking. This study investigated the biodiversity of non- yeasts associated with spontaneous fermentation of Cabernet Sauvignon wines from five sub-regions (Shi Zuishan, Yinchuan, Yu Quanying, Qing Tongxia and Hong Sibu) in Ningxia, China. Yeast species were identified by sequencing the 26S rRNA D1/D2 region, and strains at the subspecies level were discriminated using tandem repeat-tRNA (TRtRNA) PCR analysis. A total of 524 yeast colonies were isolated, and 19 non- yeast species belonging to 10 genera were identified, including , , sp., , , , , , sp., , , , , , , and . , , and were the three most dominated species, while other non- species were only present in the early stage of spontaneous fermentations at different levels. Further, for the yeast discrimination at strain level, 34 profiles were obtained by amplification with primer pairs TtRNASC/5CAG, while 40 profiles were obtained with primer pairs TtRNASC/ISSR-MB. This study explored the diversity of non- species in Ningxia, China, and made an important contribution of genetic resources for further strain development.
PubMed: 37664125
DOI: 10.3389/fmicb.2023.1253969 -
Scientific Reports Aug 2023The effect of three independent variables (i.e., tyrosine, sucrose, and incubation time) on melanin production by Aureobasidium pullulans AKW was unraveled by two...
The effect of three independent variables (i.e., tyrosine, sucrose, and incubation time) on melanin production by Aureobasidium pullulans AKW was unraveled by two distinctive approaches: response surface methodology (i.e. Box Behnken design (BBD)) and artificial neural network (ANN) in this study for the first time ever using a simple medium. Regarding BBD, sucrose and incubation intervals did impose a significant influence on the output (melanin levels), however, tyrosine did not. The validation process exhibited a high consistency of BBD and ANN paradigms with the experimental melanin production. Concerning ANN, the predicted values of melanin were highly comparable to the experimental values, with minor errors competing with BBD. Highly comparable experimental values of melanin were achieved upon using BBD (9.295 ± 0.556 g/L) and ANN (10.192 ± 0.782 g/L). ANN accurately predicted melanin production and showed more improvement in melanin production by about 9.7% higher than BBD. The purified melanin structure was verified by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction pattern (XRD), and thermogravimetric analysis (TGA). The results verified the hierarchical architecture of the particles as small compasses by SEM analysis, inter-layer spacing in the XRD analysis, maximal atomic % for carbon, and oxygen atoms in the EDX analysis, and the great thermal stability in the TGA analysis of the purified melanin. Interestingly, the current novel endophytic strain was tyrosine-independent, and the uniquely applied ANN paradigm was more efficient in modeling the melanin production with appreciate amount on a simple medium in a relatively short time (168 h), suggesting additional optimization studies for further maximization of melanin production.
Topics: Melanins; Tyrosine; Neural Networks, Computer; Sucrose
PubMed: 37598271
DOI: 10.1038/s41598-023-40549-z -
International Journal of Molecular... Dec 2023Pullulan, which is a microbial exopolysaccharide, has found widespread applications in foods, biomedicines, and cosmetics. Despite its versatility, most wild-type...
Pullulan, which is a microbial exopolysaccharide, has found widespread applications in foods, biomedicines, and cosmetics. Despite its versatility, most wild-type strains tend to yield low levels of pullulan production, and their mutants present genetic instability, achieving a limited increase in pullulan production. Therefore, mining new wild strains with robust pullulan-producing abilities remains an urgent concern. In this study, we found a novel strain, namely, ZH27, that had a remarkable pullulan-producing capacity and optimized its cultivation conditions using the one-factor-at-a-time method. To elucidate the reasons that drove the hyper-production of pullulan, we scrutinized changes in cell morphology and gene expressions. The results reveal that strain ZH27 achieved 115.4 ± 1.82 g/L pullulan with a productivity of 0.87 g/L/h during batch fermentation within 132 h under the optimized condition (OC). This pullulan titer increased by 105% compared with the initial condition (IC). Intriguingly, under the OC, swollen cells featuring 1-2 large vacuoles predominated during a rapid pullulan accumulation, while these swollen cells with one large vacuole and several smaller ones were prevalent under the IC. Moreover, the expressions of genes associated with pullulan accumulation and by-product synthesis were almost all upregulated. These findings suggest that swollen cells and large vacuoles may play pivotal roles in the high level of pullulan production, and the accumulation of by-products also potentially contributes to pullulan synthesis. This study provides a novel and promising candidate for industrial pullulan production.
Topics: Fermentation; Aureobasidium; Fungi; Glucans
PubMed: 38203490
DOI: 10.3390/ijms25010319 -
Access Microbiology 2023Fungal keratitis is a time-sensitive ocular infection that often requires a high index of suspicion followed by intensive medical/surgical interventions to achieve a...
Fungal keratitis is a time-sensitive ocular infection that often requires a high index of suspicion followed by intensive medical/surgical interventions to achieve a successful clinical outcome. COVID-19 pandemic-related restrictions, necessitated the modification of conventional protocols and guidelines associated with the treatment of keratomycosis. We report four cases of atypical fungal keratitis with poorly differentiated clinical characteristics. The challenges faced during their management were (1) the dilemma of clinically differentiating fungal () and bacterial keratitis; (2) treatment of and keratitis with natamycin monotherapy; (3) mixed infection of and and continuing medications before rescraping the corneal ulcer against the recommended treatment guidelines; (4) phenotypic identification and differentiation among morphologically resembling fungi; and (5) decision making arising out of disparities between KOH and fungal culture results. Three patients responded well to conservative treatments. The fourth patient underwent therapeutic keratoplasty but was lost to follow-up due to travelrelated pandemic restrictions. This case series seeks to broaden the clinician's knowledge of rare and emerging moulds as presumptive aetiologies of keratomycosis. It also intends to emphasize the significance of early microbiological investigations, (direct microscopy and culture), in resource-limited settings, for initiating empirical treatment for a better visual prognosis.
PubMed: 37691845
DOI: 10.1099/acmi.0.000570.v3 -
Environmental Pollution (Barking, Essex... May 2024Particulate matter with an aerodynamic diameter of 2.5 μm or less (PM) harbors a diverse microbial community. To assess the ecological dynamics and potential health...
Particulate matter with an aerodynamic diameter of 2.5 μm or less (PM) harbors a diverse microbial community. To assess the ecological dynamics and potential health risks associated with airborne microorganisms, it is crucial to understand the factors influencing microbial communities within PM. This study investigated the influence of abiotic parameters, including air pollutants, PM chemical composition (water-soluble ions and organics), and meteorological variables, on microbial communities in PM samples collected in Seoul during the spring season. Results revealed a significant correlation between air pollutants and water-soluble ions of PM with microbial α-diversity indices. Additionally, air pollutants exerted a dominant effect on the microbial community structure, with stronger correlations observed for fungi than bacteria, whereas meteorological variables including temperature, pressure, wind speed, and humidity exerted a limited influence on fungal α-diversity. Furthermore, the results revealed specific water-soluble ions, such as SO, NO, and NH, as important factors influencing fungal α-diversity, whereas K negatively correlated with both microbial α-diversity. Moreover, PM microbial diversity was affected by organic compounds within PM, with fatty acids exhibited a positive correlation with fungal diversity, while dicarboxylic acids exhibited a negative correlation with it. Furthermore, network analysis revealed direct links between air pollutants and dominant bacterial and fungal genera. The air pollutants exhibited a strong correlation with bacterial genera, such as Arthrospira and Clostridium, and fungal genera, including Aureobasidium and Cladosporium. These results will contribute to our understanding of the ecological dynamics of airborne microorganisms and provide insights into the potential risks associated with PM exposure.
Topics: Seasons; Seoul; Environmental Monitoring; Air Microbiology; Particulate Matter; Air Pollutants; Bacteria; Microbiota; Ions; Water
PubMed: 38518971
DOI: 10.1016/j.envpol.2024.123834 -
Chemistry & Biodiversity Jun 2024Three new C and C aliphatic δ-lactones (1-3), three new fatty acid methyl esters (4-6), and eight known compounds (7-14) were isolated from the marine Aureobasidium sp....
Three new C and C aliphatic δ-lactones (1-3), three new fatty acid methyl esters (4-6), and eight known compounds (7-14) were isolated from the marine Aureobasidium sp. LUO5. Their structures were established by detailed analyses of the NMR, HRESIMS, optical rotation, and ECD data. All isolates were tested for their inhibitory effects on nitric oxide production in LPS-induced BV-2 cells. Notably, compound 4 displayed the strongest inhibitory effect with the IC value of 120.3 nM.
Topics: Animals; Mice; Aureobasidium; Cell Line; Lipopolysaccharides; Molecular Conformation; Molecular Structure; Nitric Oxide; Lactones
PubMed: 38606561
DOI: 10.1002/cbdv.202400507 -
Journal of Food Science May 2024Xylanases are mainly utilized in bakery industry for the hydrolysis of dietary fiber-based fractions. Their applications in gluten-free products have not been considered...
Exploitation of Aureobasidium pullulans NRRL Y-2311-1 xylanase in mulberry and rice flours-based gluten-free cookie formulation: Effects on dough properties and cookie characteristics.
Xylanases are mainly utilized in bakery industry for the hydrolysis of dietary fiber-based fractions. Their applications in gluten-free products have not been considered before. In the present study, the xylanase produced by Aureobasidium pullulans NRRL Y-2311-1 was utilized in a mulberry and rice flours-based gluten-free cookie formulation for the first time. Effects of various xylanase concentrations on gluten-free dough rheology and cookie characteristics were elucidated. Only rice flour-based cookie and only wheat flour-based cookie formulations were also prepared as comparison. Incorporation of xylanase into all cookie recipes resulted in softer cookie doughs with lower absolute stickiness. The hardness and absolute stickiness of the cookie doughs prepared by the mixture of mulberry and rice flours decreased by the addition of the enzyme into the formulation in a concentration-dependent manner. Enzyme concentrations above 100 U/100 g flour did not provide statistically significant further changes on gluten-free cookie doughs. Incorporation of xylanase into the cookie recipes resulted in increased baking loss and spread ratio in an enzyme concentration-dependent manner for all cookie types. Hardness values of both types of gluten-free cookies decreased by xylanase incorporation. Different effects on fracturability were observed depending on the cookie type and enzyme concentration. Enzyme concentration of 100 U/100 g flour provided mulberry and rice flours-based cookies with a more flexible and softer structure. No significant effects on color parameters of cookies were observed by xylanase incorporation.
Topics: Flour; Oryza; Morus; Diet, Gluten-Free; Rheology; Ascomycota; Food Handling; Endo-1,4-beta Xylanases; Hardness; Cooking; Dietary Fiber; Triticum; Glutens
PubMed: 38563094
DOI: 10.1111/1750-3841.17054 -
Frontiers in Bioengineering and... 2024Polyol lipids (a.k.a. liamocins) produced by the polyextremotolerant, yeast-like fungus are amphiphilic molecules with high potential to serve as biosurfactants. So...
Polyol lipids (a.k.a. liamocins) produced by the polyextremotolerant, yeast-like fungus are amphiphilic molecules with high potential to serve as biosurfactants. So far, cultivations of have been performed in media with complex components, which complicates further process optimization due to their undefined composition. In this study, we developed and optimized a minimal medium, focusing on biosurfactant production. Firstly, we replaced yeast extract and peptone in the best-performing polyol lipid production medium to date with a vitamin solution, a trace-element solution, and a nitrogen source. We employed a design of experiments approach with a factor screening using a two-level-factorial design, followed by a central composite design. The polyol lipid titer was increased by 56% to 48 g L, and the space-time yield from 0.13 to 0.20 g L h in microtiter plate cultivations. This was followed by a successful transfer to a 1 L bioreactor, reaching a polyol lipid concentration of 41 g L. The final minimal medium allows the investigation of alternative carbon sources and the metabolic pathways involved, to pinpoint targets for genetic modifications. The results are discussed in the context of the industrial applicability of this robust and versatile fungus.
PubMed: 38511129
DOI: 10.3389/fbioe.2024.1379707 -
Plants (Basel, Switzerland) Sep 2023The growth of four commercial biocontrol agents (BCAs: (BAD), (APD), (MFN), and (TAS)) was evaluated using turbidimetric assays on artificial substrates mimicking...
The growth of four commercial biocontrol agents (BCAs: (BAD), (APD), (MFN), and (TAS)) was evaluated using turbidimetric assays on artificial substrates mimicking the chemical berry composition at four stages: pea-sized berries, veraison, softening, and ripe berries. The response of BCA growth differed among BCAs. Subsequently, the BCAs' population size was assessed after 1 to 13 days of incubation on the substrate mimicking ripe berries at 15 to 35 °C. The population size of BAD increased with temperatures, while that of MFN decreased; the population sizes of APD and TAS showed bell-shaped patterns with lower growth at 15 or 35 °C. Finally, the BCAs were applied to ripe berries and then incubated at 15 to 30 °C. After 1 to 13 days, the berries were inoculated with and incubated for 7 days, after which the BCA control efficacy was assessed. The highest control was observed at 25 °C for BAD and APD, at 15 to 20 °C for MFN, and at 25 to 30 °C for TAS. The results confirm that the plant substrates and temperature affect the population size of the BCA following application; temperature also affects the preventative efficacy of BCA against .
PubMed: 37836169
DOI: 10.3390/plants12193430