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Maedica Mar 2022is a widely distributed fungus that has evolved as an important pathogen, especially in immunocompromised individuals, causing fungemias, central nervous system...
is a widely distributed fungus that has evolved as an important pathogen, especially in immunocompromised individuals, causing fungemias, central nervous system infections, peritoneal dialysis-associated peritonitis and keratitis. Even though there are a few reports of skin and soft tissue infections caused by , all these cases involve immunocompromised individuals. is a Gram-positive bacterium known to cause several infections such as bloodstream, urinary tract and skin and soft tissue infections. We report a mixed and skin and soft tissue infection in a 63-year-old woman with well controlled type 2 diabetes mellitus and no other known history of immunosuppression, suffering from skin and soft tissue infection of the right lower extremity. The patient did not respond to treatment with broad spectrum antimicrobials, but had a successful outcome with fluconazole, after was isolated from pus of the skin ulcer. The antifungal treatment led to eradication of the infection, while no recurrence was observed during a follow-up period of two years. Clinicians should be aware that can cause infection even in immunocompetent patients.
PubMed: 35733763
DOI: 10.26574/maedica.2022.17.1.211 -
Frontiers in Nutrition 2022, as a member of the family , is of great value in the field of biotechnology. However, the evolutionary relationship of X-20 with , , and are not well understood, and...
, as a member of the family , is of great value in the field of biotechnology. However, the evolutionary relationship of X-20 with , , and are not well understood, and its metabolic pathways such as carotenoid biosynthesis are not well resolved. Here, genome sequencing and comparative genome techniques were employed to improve the understanding of X-20. Phytoene desaturase (crtI) and 15-cis-phytoene synthase/lycopene beta-cyclase (crtYB), key enzymes in carotenoid pathway from X-20 were more efficiently expressed in INVSc1 than in CEN.PK2-1C. High yielding engineered strains were obtained by using synthetic biology technology constructing carotenoid pathway in and optimizing the precursor supply after fed-batch fermentation with palmitic acid supplementation. Genome sequencing analysis and metabolite identification has enhanced the understanding of evolutionary relationships and metabolic pathways in X-20, while heterologous construction of carotenoid pathway has facilitated its industrial application.
PubMed: 35782944
DOI: 10.3389/fnut.2022.918240 -
Frontiers in Nutrition 2023Tofu whey wastewater (TWW) is the wastewater of tofu processing, which is rich in a variety of nutrients. can make full use of TWW to ferment and reproduce yeast cells,...
BACKGROUND
Tofu whey wastewater (TWW) is the wastewater of tofu processing, which is rich in a variety of nutrients. can make full use of TWW to ferment and reproduce yeast cells, produce carotenoids and other nutrients, improve the utilization value of TWW, and reduce environmental pollution and resource waste.
METHODS
In this study, the nutrient composition changes of TWW treated by were analyzed to reformulate TWW medium, and the optimal composition and proportion of TWW medium that can improve the biomass and carotenoids production of were explored. Meanwhile, the liquid obtained under these conditions was used to prepare biological feed for laying hens, and the effect of growing on TWW as substrate on laying performance and egg quality of laying hens were verified.
RESULTS
The results showed that the zinc content of TWW after fermentation increased by 62.30%, the phosphorus content decreased by 42.31%, and the contents of vitamin B1, B2 and B6 increased to varying degrees. The optimal fermentation conditions of in the TWW medium were as follow: the initial pH was 6.40, the amount of soybean oil, glucose and zinc ions was 0.80 ml/L, 16.32 g/L, and 20.52 mg/L, respectively. Under this condition, the biomass of reached 2.23 g/L, the carotenoids production was 832.86 μg/g, and the number of effective viable yeast count was 7.08 × 10 cfu/ml. In addition, the laying performance and egg quality of laying hens fed biological feed were improved.
DISCUSSION
In this study, we analyzed the composition changes of TWW, optimized the fermentation conditions of in TWW medium, explored the influence of utilizing TWW on laying layers, and provided a new idea for the efficient utilization of TWW.
PubMed: 36908914
DOI: 10.3389/fnut.2023.1125720 -
BMC Microbiology Aug 2020Yeasts, which are ubiquitous in agroecosystems, are known to degrade various xenobiotics. The aim of this study was to analyze the effect of fungicides on the abundance...
BACKGROUND
Yeasts, which are ubiquitous in agroecosystems, are known to degrade various xenobiotics. The aim of this study was to analyze the effect of fungicides on the abundance of natural yeast communities colonizing winter wheat leaves, to evaluate the sensitivity of yeast isolates to fungicides in vivo, and to select yeasts that degrade propiconazole.
RESULTS
Fungicides applied during the growing season generally did not affect the counts of endophytic yeasts colonizing wheat leaves. Propiconazole and a commercial mixture of flusilazole and carbendazim decreased the counts of epiphytic yeasts, but the size of the yeast community was restored after 10 days. Epoxiconazole and a commercial mixture of fluoxastrobin and prothioconazole clearly stimulated epiphyte growth. The predominant species isolated from leaves were Aureobasidium pullulans and Rhodotorula glutinis. In the disk diffusion test, 14 out of 75 yeast isolates were not sensitive to any of the tested fungicides. After 48 h of incubation in an aqueous solution of propiconazole, the Rhodotorula glutinis Rg 55 isolate degraded the fungicide in 75%. Isolates Rh. glutinis Rg 92 and Rg 55 minimized the phytotoxic effects of propiconazole under greenhouse conditions. The first isolate contributed to an increase in the dry matter content of wheat seedlings, whereas the other reduced the severity of chlorosis.
CONCLUSION
Not sensitivity of many yeast colonizing wheat leaves on the fungicides and the potential of isolate Rhodotorula glutinis Rg 55 to degrade of propiconazole was established. Yeast may partially eliminate the ecologically negative effect of fungicides.
Topics: Colony Count, Microbial; Fungicides, Industrial; Microbial Sensitivity Tests; Microbial Viability; Plant Leaves; Triazoles; Triticum; Yeasts
PubMed: 32758148
DOI: 10.1186/s12866-020-01885-6 -
Microbial Cell Factories Aug 2022The regioselective hydroxylation of phenolic compounds, especially flavonoids, is still a bottleneck of classical organic chemistry that could be solved using enzymes...
BACKGROUND
The regioselective hydroxylation of phenolic compounds, especially flavonoids, is still a bottleneck of classical organic chemistry that could be solved using enzymes with high activity and specificity. Yeast Rhodotorula glutinis KCh735 in known to catalyze the C-8 hydroxylation of flavones and flavanones. The enzyme F8H (flavonoid C8-hydroxylase) is involved in the reaction, but the specific gene has not yet been identified. In this work, we present identification, heterologous expression and characterization of the first F8H ortho-hydroxylase from yeast.
RESULTS
Differential transcriptome analysis and homology to bacterial monooxygenases, including also a FAD-dependent motif and a GD motif characteristic for flavin-dependent monooxygenases, provided a set of coding sequences among which RgF8H was identified. Phylogenetic analysis suggests that RgF8H is a member of the flavin monooxygenase group active on flavonoid substrates. Analysis of recombinant protein showed that the enzyme catalyzes the C8-hydroxylation of naringenin, hesperetin, eriodyctiol, pinocembrin, apigenin, luteolin, chrysin, diosmetin and 7,4'-dihydroxyflavone. The presence of the C7-OH group is necessary for enzymatic activity indicating ortho-hydroxylation mechanism. The enzyme requires the NADPH coenzyme for regeneration prosthetic group, displays very low hydroxyperoxyflavin decupling rate, and addition of FAD significantly increases its activity.
CONCLUSIONS
This study presents identification of the first yeast hydroxylase responsible for regioselective C8-hydroxylation of flavonoids (F8H). The enzyme was biochemically characterized and applied in in vitro cascade with Bacillus megaterium glucose dehydrogenase reactions. High in vivo activity in Escherichia coli enable further synthetic biology application towards production of rare highly antioxidant compounds.
Topics: Flavin-Adenine Dinucleotide; Flavins; Flavonoids; Hydroxylation; Mixed Function Oxygenases; Phylogeny; Rhodotorula; Substrate Specificity
PubMed: 36038906
DOI: 10.1186/s12934-022-01899-x -
Frontiers in Bioengineering and... 2020PAL (phenylalanine ammonia lyase) is important for secondary metabolite production in plants and microorganisms. There is broad interest in engineering PAL for its...
PAL (phenylalanine ammonia lyase) is important for secondary metabolite production in plants and microorganisms. There is broad interest in engineering PAL for its biocatalytic applications in industry, agriculture, and medicine. The production of quantities of high-activity enzymes has been explored by gene cloning and heterogeneous expression of the corresponding protein. Here, we cloned the cDNA of PAL (PAL) and introduced codon optimization to improve protein expression in and enzyme activities . The PAL gene was cloned by reverse transcription and named -wt. It had a full-length of 2,121 bp and encoded a 706-amino-acid protein. The -wt was inefficiently expressed in , even when the expression host and physical conditions were optimized. Therefore, codon optimization was used to obtain the corresponding gene sequence, named -opt, in order to encode the same amino acid for the PAL protein. The recombinant protein encoded by -opt, named PAL-opt, was successfully expressed in and then purified to detect its enzymatic activity . Consequently, 55.33 ± 0.88 mg/L of PAL-opt protein with a specific activity of 1,219 ± 147 U/mg and value of 609 μM for substrate L-phenylalanine was easily obtained. The enzyme protein also displayed tyrosine ammonia lyase (TAL)-specific activity of 80 ± 2 U/mg and value of 13.3 μM for substrate L-tyrosine. The bifunctional enzyme PAL/TAL (PAL-opt) and its easy expression advantage will provide an important basis for further applications.
PubMed: 33614604
DOI: 10.3389/fbioe.2020.610506 -
Iranian Journal of Microbiology Feb 2023Carotenoid pigments are among the most important pigments and have many applications in various food, cosmetics, hygiene industries and biotechnology. These pigments are...
BACKGROUND AND OBJECTIVES
Carotenoid pigments are among the most important pigments and have many applications in various food, cosmetics, hygiene industries and biotechnology. These pigments are produced by plants and microorganisms including spp. This research intended to study the antimicrobial and antibiofilm effects of the carotenoid pigment from on food spoilage bacteria ( and Typhimurium).
MATERIALS AND METHODS
The was isolated from milk samples of cows with mastitis and ITS sequence-based typing was performed on them. After extracting the pigment from , its purity was examined using thin-layer chromatography. Following that, the broth microdilution method was used to evaluate antimicrobial effects of the pigment and MtP assay and subsequently scanning electron microscopy were used to assess the antibiofilm effects. In addition, the sub-MIC effects of the pigment on expression of quorum-sensing (QS) genes in . Typhimurium isolates ( and ) and isolates () were studied. Finally, the degree of toxicity of the pigment was analyzed using the MTT assay.
RESULTS
ITS sequence analysis of revealed that the recently separated isolates exhibited strong differences with the strains recorded in NCBI database in genetic structure. The pigment produced by had strong antimicrobial effects and its mean MIC against Typhimurium isolates (17.0 μl.ml) was higher than the mean MIC against the isolates (4.1 μl.ml). Electron microscope images and real-time observations indicated that the sub-MIC values of the pigment suppressed biofilm formation by suppressing expression of QS genes. In addition, the mentioned pigment at high MIC concentrations did not have toxic effects on Vero cells.
CONCLUSION
This research suggests that pigment is effective in destroying the planktonic form of food spoilage bacteria and degrading food spoilage biofilm-forming bacteria. Moreover, considering the low toxicity level of pigment for eukaryotic cells, we can suggest its use as a natural antibacterial preservative in various food materials.
PubMed: 37069901
DOI: 10.18502/ijm.v15i1.11922 -
Frontiers in Microbiology 2021Diazinon is an organophosphorus pesticide widely used to control cabbage insects, cotton aphids and underground pests. The continuous application of diazinon in... (Review)
Review
Diazinon is an organophosphorus pesticide widely used to control cabbage insects, cotton aphids and underground pests. The continuous application of diazinon in agricultural activities has caused both ecological risk and biological hazards in the environment. Diazinon can be degraded via physical and chemical methods such as photocatalysis, adsorption and advanced oxidation. The microbial degradation of diazinon is found to be more effective than physicochemical methods for its complete clean-up from contaminated soil and water environments. The microbial strains belonging to sp., sp., , , , , and were found to be very promising for the ecofriendly removal of diazinon. The degradation pathways of diazinon and the fate of several metabolites were investigated. In addition, a variety of diazinon-degrading enzymes, such as hydrolase, acid phosphatase, laccase, cytochrome P450, and flavin monooxygenase were also discovered to play a crucial role in the biodegradation of diazinon. However, many unanswered questions still exist regarding the environmental fate and degradation mechanisms of this pesticide. The catalytic mechanisms responsible for enzymatic degradation remain unexplained, and ecotechnological techniques need to be applied to gain a comprehensive understanding of these issues. Hence, this review article provides in-depth information about the impact and toxicity of diazinon in living systems and discusses the developed ecotechnological remedial methods used for the effective biodegradation of diazinon in a contaminated environment.
PubMed: 34790174
DOI: 10.3389/fmicb.2021.717286 -
Bioengineered Dec 2019Selenium-enriched yeast can transform toxic inorganic selenium into absorbable organic selenium, which is of great significance for human health and pharmaceutical...
Selenium-enriched yeast can transform toxic inorganic selenium into absorbable organic selenium, which is of great significance for human health and pharmaceutical industry. A yeast X-20 we obtained before has good selenium-enriched ability, but its selenium content is still low for industrial application. In this study, strategies of process optimization and transport regulation of selenium were thus employed to further improve the cell growth and selenium enrichment. Through engineering phosphate transporters from into X-20, the selenium content was increased by 21.1%. Through using mixed carbon culture (20 g L, glycerol: glucose 3:7), both biomass and selenium content were finally increased to 5.3 g L and 5349.6 µg g (cell dry weight, DWC), which were 1.14 folds and 6.77 folds compared to their original values, respectively. Our results indicate that high selenium-enrichment ability and biomass production can be achieved through combining process optimization and regulation of selenium transport.
Topics: Biological Transport; Biomass; Culture Media; Fermentation; Gene Expression; Glucose; Glycerol; Metabolic Engineering; Phosphate Transport Proteins; Phosphates; Plasmids; Proton-Phosphate Symporters; Rhodotorula; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Selenium; Sodium-Phosphate Cotransporter Proteins, Type III; Transgenes
PubMed: 31322471
DOI: 10.1080/21655979.2019.1644853 -
Biotechnology For Biofuels May 2021Microbial oils, generated from lignocellulosic material, have great potential as renewable and sustainable alternatives to fossil-based fuels and chemicals. By...
BACKGROUND
Microbial oils, generated from lignocellulosic material, have great potential as renewable and sustainable alternatives to fossil-based fuels and chemicals. By unravelling the diversity of lipid accumulation physiology in different oleaginous yeasts grown on the various carbon sources present in lignocellulose hydrolysate (LH), new targets for optimisation of lipid accumulation can be identified. Monitoring lipid formation over time is essential for understanding lipid accumulation physiology. This study investigated lipid accumulation in a variety of oleaginous ascomycetous and basidiomycetous strains grown in glucose and xylose and followed lipid formation kinetics of selected strains in wheat straw hydrolysate (WSH).
RESULTS
Twenty-nine oleaginous yeast strains were tested for their ability to utilise glucose and xylose, the main sugars present in WSH. Evaluation of sugar consumption and lipid accumulation revealed marked differences in xylose utilisation capacity between the yeast strains, even between those belonging to the same species. Five different promising strains, belonging to the species Lipomyces starkeyi, Rhodotorula glutinis, Rhodotorula babjevae and Rhodotorula toruloides, were grown on undiluted wheat straw hydrolysate and lipid accumulation was followed over time, using Fourier transform-infrared (FTIR) spectroscopy. All five strains were able to grow on undiluted WSH and to accumulate lipids, but to different extents and with different productivities. R. babjevae DVBPG 8058 was the best-performing strain, accumulating 64.8% of cell dry weight (CDW) as lipids. It reached a culture density of 28 g/L CDW in batch cultivation, resulting in a lipid content of 18.1 g/L and yield of 0.24 g lipids per g carbon source. This strain formed lipids from the major carbon sources in hydrolysate, glucose, acetate and xylose. R. glutinis CBS 2367 also consumed these carbon sources, but when assimilating xylose it consumed intracellular lipids simultaneously. Rhodotorula strains contained a higher proportion of polyunsaturated fatty acids than the two tested Lipomyces starkeyi strains.
CONCLUSIONS
There is considerable metabolic diversity among oleaginous yeasts, even between closely related species and strains, especially when converting xylose to biomass and lipids. Monitoring the kinetics of lipid accumulation and identifying the molecular basis of this diversity are keys to selecting suitable strains for high lipid production from lignocellulose.
PubMed: 34051838
DOI: 10.1186/s13068-021-01974-2