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1.
Mol Biol Rep ; 47(11): 8903-8909, 2020 Nov.
Article in English | MEDLINE | ID: mdl-33130966

ABSTRACT

Luliconazole is an imidazole antifungal agent used in topical form for the treatment of onychomycosis and dermatophytosis. In vitro activity of luliconazole against dermatophytes, Candida, black fungi, Fusarium and Aspergillus species have been investigated. Rhodotorula spp. are environmental yeasts and emerged as opportunistic pathogens among immunocompromised patients. Rhodotorula's human infections are usually resistant to treatment with antifungal drugs especially triazoles and echinocandins. The present study aimed at the molecular detection of environmental isolates of Rhodotorula spp. Then, antifungal efficacy of luliconazole was evaluated against isolates and compared to other routine systemic antifungals including; caspofungin, posaconazole, fluconazole, itraconazole, amphotericin B, and voriconazole. The biofilm production of Rhodotorula isolates was also evaluated. In this study, 39 isolates of Rhodotorula spp. were isolated from the environment, detected using molecular methods, and tested against luliconazole. Then, the anti-fungal activity of luliconazole compared with several routine antifungals. Also, biofilm formation by using a crystal violet staining assay was performed. Our finding showed that luliconazole has a very high minimum inhibitory concentration (MIC) value (1-8 µg/ml) against Rhodotorula spp. Besides, 100% of Rhodotorula strains were resistant to caspofungin, followed by fluconazole 94.7% and voriconazole 74.4%. Amphotericin B was demonstrated excellent in vitro activity against this genus. Our result indicated that 59% of Rhodotorula spp. were in the mid-range of biofilm production. Our results indicated that luliconazole does not effective against the genus Rhodotorula. Furthermore, amphotericin B is the best drug against this genus in comparison to caspofungin and other azole drugs.


Subject(s)
Biofilms/drug effects , Imidazoles/pharmacology , Microbial Sensitivity Tests/methods , Rhodotorula/drug effects , Amphotericin B/pharmacology , Antifungal Agents/pharmacology , Biofilms/growth & development , Caspofungin/pharmacology , DNA, Fungal/genetics , DNA, Ribosomal Spacer/genetics , Fluconazole/pharmacology , Humans , Itraconazole/pharmacology , Phylogeny , Rhodotorula/classification , Rhodotorula/physiology , Species Specificity , Triazoles/pharmacology , Voriconazole/pharmacology
2.
Ecotoxicol Environ Saf ; 194: 110441, 2020 May.
Article in English | MEDLINE | ID: mdl-32155484

ABSTRACT

Vesicles (Ves) within fungal cells are the critical linkage between intracellular and extracellular systems. This study explored the application of Pb2+ to probe the physiology of intracellular Ves in Rhodotorula mucilaginosa (Rho). At low Pb2+ levels (0-500 mg/L), there was no evident change in the content of extracellular polymeric substances (EPS) or microbial activity. At medium-high levels (1000-2000 mg/L), the sizes of Ves within the Rho cells were significantly enlarged, with abundant lead nano-particles (Pb NPs) formed either on the cell surface or interior, whereas the EPS content and bioactivity were still stable. At a high level (2500 mg/L), the Rho cells were severely deformed, with cell counts reduced by more than 99%. However, the EPS contents and the respiration rate of the surviving cells dramatically increased to the maximum values (i.e., 1785 mg/1010 cells and 37 mg C 10-10 cells h-1, respectively). The Ves surface adsorbed Pb cations with higher density, compared with the cell membrane. Moreover, fusion of some Ves to the membrane (functioning in transport) was observed under transmission electron microscope (TEM). Three pathways of detoxification via intracellular Ves were finally proposed, i.e., Ve-mediated transport (from intracellular to extracellular) of EPS components, absorption of Pb NPs on the Ve surface, and accumulation of Pb NPs within Ves. This study sheds light on the possibility of exploring microbial physiology via Pb2+ cations.


Subject(s)
Hazardous Substances/toxicity , Lead/toxicity , Rhodotorula/physiology , Adsorption , Cations , Toxicity Tests
3.
J Basic Microbiol ; 59(9): 879-889, 2019 Sep.
Article in English | MEDLINE | ID: mdl-31339587

ABSTRACT

Metallothionein (MT) is a low-molecular-weight protein with a high metal binding capacity and plays a key role in organism adaptation to heavy metals. In this study, a metallothionein gene was successfully cloned and sequenced from Antarctic sea-ice yeast Rhodotorula mucilaginosa AN5. Nucleotide sequencing and analysis revealed that the gene had four exons interrupted by three introns. MTs complementary DNA (named as RmMT) had an open reading frame of 321 bp encoding a 106 amino acid protein with a predicted molecular weight of 10.3 kDa and pI of 8.49. The number of amino acids and distribution of cysteine residues indicated that RmMT was a novel family of fungal MTs. Quantitative real-time polymerase chain reaction analysis showed that RmMT expression was elevated under copper-induced stress. The RmMT gene was transferred into E. coli and the RmMT expressing bacteria showed improved tolerance to copper ion and increased accumulation of heavy metals, such as Cu2+ , Pb2+ , Zn2+ , Cd2+ , and Ag+ . Moreover, in vitro studies, purified recombinant RmMT demonstrated that it could be used as a good scavenger of superoxide anion, hydroxyl, and 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radicals. In summary, these results demonstrate that RmMT plays a key role in the tolerance and bioaccumulation of heavy metals.


Subject(s)
Ice Cover/microbiology , Metallothionein/genetics , Metallothionein/metabolism , Metals, Heavy/metabolism , Rhodotorula/genetics , Adaptation, Physiological/genetics , Antarctic Regions , Antioxidants/isolation & purification , Antioxidants/metabolism , Base Sequence , Cloning, Molecular , Copper/metabolism , Escherichia coli/genetics , Escherichia coli/physiology , Fungal Proteins/genetics , Fungal Proteins/isolation & purification , Fungal Proteins/metabolism , Gene Expression , Metallothionein/isolation & purification , Open Reading Frames , Recombinant Proteins/genetics , Recombinant Proteins/isolation & purification , Recombinant Proteins/metabolism , Rhodotorula/physiology
4.
J Appl Microbiol ; 127(4): 1069-1079, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31237965

ABSTRACT

AIMS: To evaluate an aqueous extract of Macrocystis pyrifera as a nutrient source for the production of carotenoids by a marine Rhodotorula mucilaginosa isolated from seaweed samples. MATERIALS AND RESULTS: The effect of different culture conditions on the concentration of biomass and total pigments was evaluated using a Box-Behnken experimental design. The seaweed extract contained 15% w w-1 of protein and 20% w w-1 of carbohydrate; the main sugar in this fraction was trehalose (78%). The culture conditions that maximize the total pigment concentration (1·84 ± 0·03 mg l-1 ) were initial pH equal to 7, yeast extract as nitrogen source at a concentration of 4 g l-1 , seaweed extract concentration at 25% v v-1 , incubation performed at 25°C and 150 rev min-1 during 6 days. Under optimal growth conditions, three carotenoids were identified among the pigments produced by R. mucilaginosa, lycopene (38·4 ± 9·4%), ß-carotene (21·8 ± 1·5%) and astaxanthin (1·8 ± 0·3%). CONCLUSIONS: Carotenoids of commercial interest (lycopene, ß-carotene and astaxanthin) can be produced using a marine R. mucilaginosa cultivated with an aqueous extract of M. pyrifera as nutrient source. The total pigment concentration in the culture ranged between 0·82 and 1·84 mg l-1 , and was significantly affected by the concentration of the seaweed extract, and yeast extract. SIGNIFICANCE AND IMPACT OF THE STUDY: This work demonstrates that M. pyrifera can be used as a nutrient source for the production of carotenoids by the marine yeast.


Subject(s)
Carotenoids , Macrocystis/chemistry , Rhodotorula , Biomass , Bioreactors , Carotenoids/analysis , Carotenoids/metabolism , Culture Media , Rhodotorula/metabolism , Rhodotorula/physiology
5.
DNA Res ; 26(2): 131-146, 2019 Apr 01.
Article in English | MEDLINE | ID: mdl-30615101

ABSTRACT

Endophytic yeasts of genus Rhodotorula are gaining importance for their ability to improve plant growth. The nature of their interaction with plants, however, remains unknown. Rhodotorula mucilaginosa JGTA-S1 was isolated as an endophyte of Typha angustifolia and promoted growth in the host. To investigate the life-strategy of the yeast from a genomics perspective, we used Illumina and Oxford Nanopore reads to generate a high-quality annotated draft assembly of JGTA-S1 and compared its genome to three other Rhodotorula yeasts and the close relative Rhodosporidium toruloides. JGTA-S1 is a haploid yeast possessing several genes potentially facilitating its endophytic lifestyle such as those responsible for solubilizing phosphate and producing phytohormones. An intact mating-locus in JGTA-S1 raised the possibility of a yet unknown sexual reproductive cycle in Rhodotorula yeasts. Additionally, JGTA-S1 had functional anti-freezing genes and was also unique in lacking a functional nitrate-assimilation pathway-a feature that is associated with obligate biotrophs. Nitrogen-fixing endobacteria were found within JGTA-S1 that may circumvent this defective N-metabolism. JGTA-S1 genome data coupled with experimental evidence give us an insight into the nature of its beneficial interaction with plants.


Subject(s)
Endophytes , Genome, Fungal , Metabolic Networks and Pathways , Rhodotorula/genetics , Symbiosis , Bacteria/metabolism , Genomics , Nitrogen/metabolism , Pseudomonas stutzeri/metabolism , Rhodotorula/metabolism , Rhodotorula/physiology , Sequence Analysis, DNA , Typhaceae
6.
Int J Biol Macromol ; 121: 55-62, 2019 Jan.
Article in English | MEDLINE | ID: mdl-30290257

ABSTRACT

The capability of plant growth promoting microbes to survive under abiotic stresses has important significance for improving plant growth and productivity. Among the various plant growth promoting biomolecules produced by microbes, exopolysaccharide (EPS) help microbes to survive in inhospitable environments and endure environmental stressful conditions. In the present study, a yeast strain CAH2 was isolated from Beta vulgaris rhizosphere soil and identified as Rhodotorula sp., based on the partial 18S rRNA gene sequence analysis. Rhodotorula sp. strain CAH2 was found to tolerate higher concentrations of Al (6 mM), NaCl (150 mM) and PEG-6000 (15%, w/v). The strain CAH2 was shown to produce 7.5 g L-1 of EPS in the production medium with sucrose and yeast extract as a carbon and nitrogen sources, respectively. The EPS yield was increased constantly with increasing concentrations of Al, NaCl and PEG-6000. The structural feature of EPS studied through FT-IR and NMR spectral analysis confirmed the presence of glucose, mannose and galactose. The yeast strain CAH2 was produced multiple plant growth promoting traits in the presence and absence of abiotic stresses. Finally, these results indicate that the production of EPS could be safeguard the plant growth promoting Rhodotorula sp. strain CAH2 from unfavourable environmental conditions.


Subject(s)
Fungal Polysaccharides/biosynthesis , Plant Development , Plants/microbiology , Rhodotorula/physiology , Stress, Physiological , Fungal Polysaccharides/chemistry , Rhodotorula/metabolism
7.
Fish Physiol Biochem ; 45(2): 511-521, 2019 Apr.
Article in English | MEDLINE | ID: mdl-30519984

ABSTRACT

Defense mechanisms of fish are investigated in many aspects. One of the most interesting systems is that based on non-specific immune factors whose mechanisms of biocontrol have evolved in complex processes of microbiological co-existence. The wild fish devoid of probiotic stimulation have developed their own system to control the biosynthesis of immunostimulating compounds based on commensal microflora. Results of this study demonstrated the gastrointestinal tract (GI) of wild fish (Abramis brama, Rutilus rutilus, Perca fluviatilis) was colonized by permanently residing strains of Rhodotorula mucilaginosa. The genetic profile of the tested strains (PCR-random amplification of polymorphic DNA) indicated their affinity only to the GI of the analyzed fish. The capability for biosynthesis of ß-carotene, torulene, torularhodin, and exopolysaccharides (EPS) under conditions of fish gastrointestinal tract was found to be a strain-specific trait. Rhodotorula spp. interactions with fish should be considered as a mechanism of symbiotic relations based on the stimulation of non-specific mechanisms of fish immunoprotection and antioxidative properties of yeast.


Subject(s)
Fishes/microbiology , Fishes/physiology , Gastrointestinal Tract/microbiology , Rhodotorula/physiology , Animals , Budesonide, Formoterol Fumarate Drug Combination , Genetic Variation , Rhodotorula/genetics
8.
Trends Biotechnol ; 36(3): 304-317, 2018 03.
Article in English | MEDLINE | ID: mdl-29132754

ABSTRACT

Moving our society towards a bioeconomy requires efficient and sustainable microbial production of chemicals and fuels. Rhodotorula (Rhodosporidium) toruloides is a yeast that naturally synthesizes substantial amounts of specialty chemicals and has been recently engineered to (i) enhance its natural production of lipids and carotenoids, and (ii) produce novel industrially relevant compounds. The use of R. toruloides by companies and research groups has exponentially increased in recent years as a result of recent improvements in genetic engineering techniques and the availability of multiomics information on its genome and metabolism. This review focuses on recent engineering approaches in R. toruloides for bioproduction and explores its potential as a biotechnological chassis.


Subject(s)
Biotechnology , Genetic Engineering , Metabolic Engineering , Rhodotorula/physiology , Carotenoids/biosynthesis , Gene Editing , Genome, Fungal/genetics , Genomics , Lipids/biosynthesis , Metabolomics , Proteomics , Rhodotorula/genetics
9.
Water Sci Technol ; 76(3-4): 806-812, 2017 Aug.
Article in English | MEDLINE | ID: mdl-28799927

ABSTRACT

The aim of the study was to examine heavy metal tolerance (Cd2+, Zn2+, Ni2+ and Cu2+) of single- and mixed-species biofilms (Rhodotorula mucilaginosa and Escherichia coli) and to determine metal removal efficiency (Cd2+, Zn2+, Ni2+, Cu2+, Pb2+ and Hg2+). Metal tolerance was quantified by crystal violet assay and results were confirmed by fluorescence microscopy. Metal removal efficiency was determined by batch biosorption assay. The tolerance of the mixed-species biofilm was higher than the single-species biofilms. Single- and mixed-species biofilms showed the highest sensitivity in the presence of Cu2+ (E. coli-MIC 4 mg/ml, R. mucilaginosa-MIC 8 mg/ml, R. mucilaginosa/E. coli-MIC 64 mg/ml), while the highest tolerance was observed in the presence of Zn2+ (E. coli-MIC 80 mg/ml, R. mucilaginosa-MIC 161 mg/ml, R. mucilaginosa-E. coli-MIC 322 mg/ml). The mixed-species biofilm exhibited better efficiency in removal of all tested metals than single-species biofilms. The highest efficiency in Cd2+ removal was shown by the E. coli biofilm (94.85%) and R. mucilaginosa biofilm (97.85%), individually. The highest efficiency in Cu2+ (99.88%), Zn2+ (99.26%) and Pb2+ (99.52%) removal was shown by the mixed-species biofilm. Metal removal efficiency was in the range of 81.56%-97.85% for the single- and 94.99%-99.88% for the mixed-species biofilm.


Subject(s)
Biofilms/growth & development , Escherichia coli/drug effects , Metals, Heavy/metabolism , Metals, Heavy/toxicity , Rhodotorula/drug effects , Escherichia coli/physiology , Rhodotorula/physiology
11.
Can J Microbiol ; 61(10): 763-9, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26308797

ABSTRACT

The aim of this study was to characterize the yeast microbiota of natural cavities of manatees kept in captivity in Brazil. Sterile swabs from the oral cavity, nostrils, genital opening, and rectum of 50 Trichechus inunguis and 26 Trichechus manatus were collected. The samples were plated on Sabouraud agar with chloramphenicol and incubated at 25 °C for 5 days. The yeasts isolated were phenotypically identified by biochemical and micromorphological tests. Overall, 141 strains were isolated, of which 112 were from T. inunguis (Candida albicans, Candida parapsilosis sensu stricto, Candida orthopsilosis, Candida metapsilosis, Candida guilliermondii, Candida pelliculosa, Candida tropicalis, Candida glabrata, Candida famata, Candida krusei, Candida norvegensis, Candida ciferri, Trichosporon sp., Rhodotorula sp., Cryptococcus laurentii) and 29 were from T. manatus (C. albicans, C. tropicalis, C. famata, C. guilliermondii, C. krusei, Rhodotorula sp., Rhodotorula mucilaginosa, Rhodotorula minuta, Trichosporon sp.). This was the first systematic study to investigate the importance of yeasts as components of the microbiota of sirenians, demonstrating the presence of potentially pathogenic species, which highlights the importance of maintaining adequate artificial conditions for the health of captive manatees.


Subject(s)
Microbiota , Trichechus/microbiology , Animals , Brazil , Candida/isolation & purification , Candida/physiology , Cryptococcus/isolation & purification , Cryptococcus/physiology , Female , Male , Rhodotorula/isolation & purification , Rhodotorula/physiology , Trichechus inunguis/microbiology , Trichechus manatus/microbiology , Trichosporon/isolation & purification , Trichosporon/physiology
12.
Yeast ; 32(11): 683-90, 2015 Nov.
Article in English | MEDLINE | ID: mdl-26284451

ABSTRACT

This study aimed to investigate the correlation between the cold adaptation of Rhodotorula glutinis YM25079 and the membrane fluidity, content of polyunsaturated fatty acids and mRNA expression level of the Δ(12)-desaturase gene. The optimum temperature for YM25079 growth was analysed first, then the composition changes of membrane lipid in YM25079 were detected by GC-MS and membrane fluidity was evaluated by 1-anilinonaphthalene-8-sulphonate (ANS) fluorescence. Meanwhile, the encoding sequence of Δ(12)-fatty acid desaturase in YM25079 was cloned and further transformed into Saccharomyces cerevisiae INVScl for functional analysis. The mRNA expression levels of Δ(12)-fatty acid desaturase at 15°C and 25°C were analysed by real-time PCR. YM25079 could grow at 5-30°C, with the optimum temperature of 15°C. The membrane fluidity of YM25079 was not significantly reduced when the culture temperature decreased from 25°C to 15°C, but the content of polyunsaturated fatty acids (PUFAs), including linoleic acid and α-Linolenic acid increased significantly from 29.4% to 55.39%. Furthermore, a novel Δ(12)-fatty acid desaturase gene YM25079RGD12 from YM25079 was successfully identified and characterized, and the mRNA transcription level of the Δ(12)-desaturase gene was about five-fold higher in YM25079 cells grown at 15°C than that at 25°C. These results suggests that the cold adaptation of Rhodotorula glutinis YM25079 might result from higher expression of genes, especially the Δ(12)-fatty acid desaturase gene, during polyunsaturated fatty acids biosynthesis, which increased the content of PUFAs in the cell membrane and maintained the membrane fluidity at low temperature.


Subject(s)
Adaptation, Physiological/physiology , Fatty Acids, Unsaturated/metabolism , Rhodotorula/physiology , Amino Acid Sequence , Cell Membrane/physiology , Cloning, Molecular , Cold Temperature , Fatty Acid Desaturases/genetics , Fatty Acid Desaturases/metabolism , Fatty Acids, Unsaturated/genetics , Gene Expression , Linoleic Acid/metabolism , Membrane Fluidity/physiology , Molecular Sequence Data , RNA, Messenger/genetics , RNA, Messenger/metabolism , Rhodotorula/genetics , Rhodotorula/growth & development , Rhodotorula/metabolism , Saccharomyces cerevisiae/genetics , alpha-Linolenic Acid/metabolism
13.
Biocontrol Sci ; 20(2): 91-7, 2015.
Article in English | MEDLINE | ID: mdl-26133506

ABSTRACT

The killing effect of peppermint vapor (PMV) against pink-slime forming microorganisms, Methylobacterium mesophilicum as a bacterium and Rhodotorula mucilaginosa as a yeast, was investigated by the agar vapor assay. In this method, microbial cells were spread over the agar surface exposed to PMV in a petri dish, and then transferred into a recovery liquid. When 60µl of the peppermint liquid was added to a paper disc, a marked killing effect of PMV was observed after 48h against M. mesophilicum and after 168h against R. mucilaginosa. M. mesophilicum and R. mucilaginosa were found to be more resistant to PMV than Escherichia coli and Candida albicans, used as reference microorganisms, respectively. With the addition of 0.03% sodium pyruvate as a hydrogen peroxide scavenger in agar, the killing effect of PMV against E. coli and C. albicans was decreased, whereas it was little changed against M. mesophilicum and R. mucilaginosa. In fact, the properties of the killing effect of hydrogen peroxide solution at 0.2-1.0mM was in accord with those of PMV. M. mesophilicum and R. mucilaginosa were more resistant to the oxidant than E. coli and C. albicans, respectively. Results obtained suggested that reactive oxygen species (ROS) may be involved in the killing action of PMV and therefore pink-slime formers are more resistant to PMV than non-pink-slime formers because of the presence of carotenoids as an antioxidant in cells. We also suggest that the use of PMV appeared to be a potential tool for the control of pink-slime forming microorganisms occurring in wet areas of houses such as the bathroom and washing room.


Subject(s)
Anti-Infective Agents/pharmacology , Biofilms/drug effects , Mentha piperita/chemistry , Methylobacterium/drug effects , Rhodotorula/drug effects , Volatile Organic Compounds/pharmacology , Anti-Infective Agents/isolation & purification , Candida albicans/drug effects , Candida albicans/physiology , Escherichia coli/drug effects , Escherichia coli/physiology , Methylobacterium/physiology , Microbial Viability/drug effects , Rhodotorula/physiology , Volatile Organic Compounds/isolation & purification
14.
J Zhejiang Univ Sci B ; 16(4): 275-85, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25845361

ABSTRACT

A total of 20 strains of yeast isolated from Tibetan fermented products were screened for antagonism against blue mold of pear caused by Penicillium expansum. Six isolates that inhibited incidence of postharvest decay by 35% or more were selected for further screening. Among them, the most effective was Rhodotorula mucilaginosa. The results showed that washed cell suspensions of R. mucilaginosa yielded better antagonistic efficacy than unwashed cell-culture mixtures, cell-free culture filtrates, and autoclaved cell cultures. Biocontrol activity improved with increasing concentrations of incubated cells. The best concentration was 1×10(8) cells/ml, at which the incidence of decay was only 16.7% after 6 d of incubation. The germination of conidia of P. expansum in vitro was significantly inhibited by both washed cell-suspensions and unwashed cell-culture mixtures. Rapid colonization by yeast at different concentrations showed a relationship between yeast-cell concentration and biocontrol activity. Although the titratable acidity of pear fruits increased after treatment, R. mucilaginosa did not affect the total soluble solids or ascorbic acid content. This is the first study to report that the yeast R. mucilaginosa from Tibet Autonomous Region of China may have potential as an antagonist to control the postharvest decay of pear fruits.


Subject(s)
Penicillium/physiology , Pest Control, Biological/methods , Plant Diseases/microbiology , Plant Diseases/prevention & control , Pyrus/microbiology , Rhodotorula/physiology , Tibet
15.
J Basic Microbiol ; 55(8): 1029-39, 2015 Aug.
Article in English | MEDLINE | ID: mdl-25727311

ABSTRACT

A yeast producing a cold-adapted phytase was isolated from Antarctic deep-sea sediment and identified as a Rhodotorula mucilaginosa strain JMUY14 of basidiomycetous yeasts. It was cultured in fermentation optimized by a response surface methodology based on the Box-Behnken design. The maximum activity of phytase reached 205.447 U ml(-1), which was close to the predicted value of 201.948 U ml(-1) and approximately 3.4 times higher than its initial activity. The extracellular phytase was purified by 15.2-fold to homogeneity with a specific activity of 31,635 U mg(-1) by (NH4 )2 SO4 precipitation, and a combination of DEAE Sepharose Fast Flow, SP Sepharose Fast Flow, and Sephadex G-100. The molecular weight of the purified enzyme was estimated to be 63 kDa and its pI was 4.33. Its optimal temperature and pH were 50 °C and 5.0, respectively. Its activity was 85% at 37 °C, and showed good stability at pH 3.0 ∼ 7.0. When compared with mesophilic counterparts, the phytase not only exhibited a higher activity during 20 ∼ 30 °C but also had a low Km (247 µM) and high kcat (1394 s(-1)). The phytase activity was slightly stimulated in the presence of Mg(2+), Fe(2+), Fe(3+), K(+), Na(+), Ca(2+), EDTA, and EGTA and moderately inhibited by Cu(2+), Zn(2+), Mn(2+), Ag(+), PMSF, SDS, and phenylgloxal hydrate. It was resistant to both pepsin and trypsin. Since the phytase produced by the R. mucilaginosa JMUY14 showed a high specific activity, good pH stability, strong protease resistance, and high activity at low temperature, it has great potential for feed applications, especially in aquaculture.


Subject(s)
6-Phytase/isolation & purification , 6-Phytase/metabolism , Adaptation, Physiological , Cold Temperature , Geologic Sediments/microbiology , Rhodotorula/enzymology , 6-Phytase/antagonists & inhibitors , 6-Phytase/chemistry , Amino Acid Sequence , Antarctic Regions , Aquaculture , Enzyme Stability , Fermentation , Hydrogen-Ion Concentration , Kinetics , Molecular Weight , Pepsin A/metabolism , Phylogeny , Rhodotorula/isolation & purification , Rhodotorula/physiology , Substrate Specificity , Trypsin/metabolism
16.
Int J Food Microbiol ; 193: 152-8, 2015 Jan 16.
Article in English | MEDLINE | ID: mdl-25462935

ABSTRACT

The use of antagonistic yeasts to control postharvest pathogens is a promising alternative to fungicides. The effectiveness of the antagonists against fungal pathogens is greatly dependent on their viability, which is usually mediated by reactive oxygen species (ROS). Here, we investigated the effects of H2O2-induced oxidative stress on the viability and biocontrol efficacy of Rhodotorula glutinis and, using flow cytometric analysis, observed the changes of ROS accumulation and apoptosis in the yeast cells with or without H2O2 treatment. We found that the viability of R. glutinis decreased in a time- and dose-dependent manner under H2O2-induced oxidative stress. Compared to the control, yeast cells exposed to oxidative stress exhibited more accumulation of ROS and higher levels of protein oxidative damage, but showed lower efficacy for biocontrol of Penicillium expansum causing blue mold rot on peach fruit. The results indicate that apoptosis is a main cause of the cell viability loss in R. glutinis, which is attributed to ROS accumulation under oxidative stress. These findings offer a plausible explanation that oxidative stress affects biocontrol efficacy of R. glutinis via regulating its viability and cell apoptosis.


Subject(s)
Food Microbiology , Hydrogen Peroxide/pharmacology , Microbial Viability , Oxidative Stress/drug effects , Rhodotorula/drug effects , Rhodotorula/physiology , Antibiosis/drug effects , Apoptosis/drug effects , Fungicides, Industrial/pharmacology , Penicillium/growth & development , Prunus/microbiology , Reactive Oxygen Species/metabolism
17.
PLoS One ; 9(5): e97221, 2014.
Article in English | MEDLINE | ID: mdl-24825453

ABSTRACT

Novel hybrid magnetic cross-linked enzyme aggregates of phenylalanine ammonia lyase (HM-PAL-CLEAs) were developed by co-aggregation of enzyme aggregates with magnetite nanoparticles and subsequent crosslinking with glutaraldehyde. The HM-PAL-CLEAs can be easily separated from the reaction mixture by using an external magnetic field. Analysis by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) indicated that PAL-CLEAs were inlayed in nanoparticle aggregates. The HM-PAL-CLEAs revealed a broader limit in optimal pH compared to free enzyme and PAL-CLEAs. Although there is no big difference in Km of enzyme in CLEAs and HM-PAL-CLEAs, Vmax of HM-PAL-CLEAs is about 1.75 times higher than that of CLEAs. Compared with free enzyme and PAL-CLEAs, the HM-PAL-CLEAs also exhibited the highest thermal stability, denaturant stability and storage stability. The HM-PAL-CLEAs retained 30% initial activity even after 11 cycles of reuse, whereas PAL-CLEAs retained 35% of its initial activity only after 7 cycles. These results indicated that hybrid magnetic CLEAs technology might be used as a feasible and efficient solution for improving properties of immobilized enzyme in industrial application.


Subject(s)
Biotechnology/methods , Magnetite Nanoparticles/chemistry , Phenylalanine Ammonia-Lyase/metabolism , Protein Aggregates/physiology , Rhodotorula/enzymology , Cross-Over Studies , Glutaral/metabolism , Hydrogen-Ion Concentration , Kinetics , Magnetics , Microscopy, Confocal , Microscopy, Electron, Scanning , Rhodotorula/physiology
18.
J Agric Food Chem ; 62(18): 4214-24, 2014 May 07.
Article in English | MEDLINE | ID: mdl-24724730

ABSTRACT

The effect of Rhodotorula mucilaginosa cultured in media containing chitosan on its antogonistic activity against postharvest diseases of strawberries and the possible mechanisms involved are discussed. Two-dimensional gel electrophoresis were applied in the analysis of the proteins of R. mucilaginosa in response to chitosan. Compared with the application of R. mucilaginosa alone, the biocontrol efficacy of the yeast combined with 0.5% chitosan was enhanced greatly, with significant increase in chitinase activity of antagonistic yeast, polyphenoloxidase, peroxidase, phenylalanine ammonia lyase, chitinase and ß-1,3-glucanase activity, and with an inhibition of lipid peroxidation of strawberries. The population of R. mucilaginosa harvested from NYDB amended with chitosan at 0.5% increased rapidly in strawberry wounds compared with those harvested from NYDB without chitosan. In the cellular proteome, several differentially expressed proteins were identified, most of which were related to basic metabolism.


Subject(s)
Antibiosis , Chitosan/metabolism , Fragaria/microbiology , Plant Diseases/prevention & control , Rhodotorula/growth & development , Rhodotorula/physiology , Chitinases/chemistry , Chitinases/genetics , Chitinases/metabolism , Culture Media/chemistry , Culture Media/metabolism , Fragaria/chemistry , Fungal Proteins/chemistry , Fungal Proteins/genetics , Fungal Proteins/metabolism , Plant Diseases/microbiology , Rhodotorula/chemistry , Rhodotorula/genetics
19.
Carbohydr Polym ; 98(1): 366-71, 2013 Oct 15.
Article in English | MEDLINE | ID: mdl-23987356

ABSTRACT

The influence of adding burdock fructooligosaccharide (BFO) in the culture media on the efficacy of Rhodotorula mucilaginosa in controlling postharvest decay of peaches and its possible mode of action were investigated. The antagonistic activity of R. mucilaginosa to Rhizopus decay and blue mold decay of peaches was greatly enhanced through cultivation in the nutrient yeast dextrose agar (NYDA) medium amended with BFO at the concentration of 0.32%, compared with that cultivated in NYDB without BFO. R. mucilaginosa at 1×10(8) cells/mL cultivation in the NYDB media did not reduce the natural decay incidence of peaches, compared with the control after 30 d at 4 °C followed by 7d at 20 °C. However, R. mucilaginosa cultivation in the NYDB media amended with BFO at the concentration of 0.32% reduced the natural decay incidence of peaches. The population of R. mucilaginosa harvested from NYDB amended with BFO at 0.32% increased rapidly in peach wounds compared to that harvested from NYDB without BFO no matter peaches were stored at 20 °C or 4 °C. The activities of chitinase and ß-1,3-glucanase of cell-free culture filtrate of R. mucilaginosa harvested from NYDB amended with BFO at 0.32% were higher than that at other concentrations and the control.


Subject(s)
Arctium/chemistry , Oligosaccharides/pharmacology , Prunus/microbiology , Rhodotorula/drug effects , Rhodotorula/physiology , Chitinases/metabolism , Culture Media/chemistry , Food Quality , Glucan 1,3-beta-Glucosidase/metabolism , Rhizopus/physiology , Rhodotorula/enzymology , Rhodotorula/growth & development
20.
Microbiol Res ; 168(10): 630-8, 2013 Dec 14.
Article in English | MEDLINE | ID: mdl-23827647

ABSTRACT

A series of gemini quaternary ammonium chlorides and bromides with various alkyl chain and spacer lengths was synthesized. The most active compounds against fungi were chlorides with 10 carbon atoms within the hydrophobic chain. Among these compounds were few with no hemolytic activity at minimal inhibitory concentrations. None of the tested compounds were cytotoxic and mutagenic. Cationic gemini surfactants poorly reduced the adhesion of microorganisms to the polystyrene plate, but inhibited the filamentation of Candida albicans. One of the tested compounds eradicated C. albicans and Rodotorula mucilaginosa biofilm, what could be important in overcoming catheter-associated infections. It was also shown that gemini surfactants enhanced the sensitivity of C. albicans to azoles and polyenes, thus they might be potentially used in combined therapy against fungi.


Subject(s)
Antifungal Agents/pharmacology , Quaternary Ammonium Compounds/pharmacology , Animals , Antifungal Agents/chemical synthesis , Biofilms/drug effects , Candida albicans/drug effects , Candida albicans/physiology , Cell Adhesion/drug effects , Erythrocytes/drug effects , Hemolysis , Microbial Sensitivity Tests , Microbial Viability/drug effects , Mutation Rate , Quaternary Ammonium Compounds/chemical synthesis , Rhodotorula/drug effects , Rhodotorula/physiology , Saccharomyces cerevisiae/drug effects , Saccharomyces cerevisiae/physiology , Salmonella typhimurium/drug effects , Sheep
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