Antifungal effects of a 1,3,4-thiadiazole derivative determined by cytochemical and vibrational spectroscopic studies.

Compounds belonging to the group of 5-substituted 4-(1,3,4-thiadiazol-2-yl) benzene-1,3-diols exhibit a broad spectrum of biological activity, including antibacterial, antifungal, and anticancer properties. The mechanism of the antifungal activity of compounds from this group has not been described to date. Among the large group of 5-substituted 4-(1,3,4-thiadiazol-2-yl) benzene-1,3-diol derivatives, the compound 4-(5-methyl-1,3,4-thiadiazole-2-yl) benzene-1,3-diol, abbreviated as C1, was revealed to be one of the most active agents against pathogenic fungi, simultaneously with the lowest toxicity to human cells. The C1 compound is a potent antifungal agent against different Candida species, including isolates resistant to azoles, and molds, with MIC100 values ranging from 8 to 96 µg/ml. The antifungal activity of the C1 compound involves disruption of the cell wall biogenesis, as evidenced by the inability of cells treated with C1 to maintain their characteristic cell shape, increase in size, form giant cells and flocculate. C1-treated cells were also unable to withstand internal turgor pressure causing protoplast material to leak out, exhibited reduced osmotic resistance and formed buds that were not covered with chitin. Disturbances in the chitin septum in the neck region of budding cells was observed, as well as an uneven distribution of chitin and ß(1→3) glucan, and increased sensitivity to substances interacting with wall polymerization. The ATR-FTIR spectral shifts in cell walls extracted from C. albicans cells treated with the C1 compound suggested weakened interactions between the molecules of ß(1→3) glucans and ß(1→6) glucans, which may be the cause of impaired cell wall integrity. Significant spectral changes in the C1-treated cells were also observed in bands characteristic for chitin. The C1 compound did not affect the ergosterol content in Candida cells. Given the low cytotoxicity of the C1 compound to normal human dermal fibroblasts (NHDF), it is possible to use this compound as a therapeutic agent in the treatment of surface and gastrointestinal tract mycoses.

Effects of dietary hydrolyzed yeast (Rhodotorula mucilaginosa) on growth performance, immune response, antioxidant capacity and histomorphology of juvenile Nile tilapia (Oreochromis niloticus).

An 8 weeks feeding experiment was conducted to evaluate the effects of dietary supplementation with hydrolyzed yeast (HY) (Rhodotorula mucilaginosa) on growth performance, hematological parameters, immune response and antioxidant ability of juvenile Nile tilapia. Five isonitrogenous and isolipidic diets (32% protein and 4% lipid) with different levels (0%, 0.125%, 0.25%, 0.5%, 1%) of HY were formulated. Each diet was randomly assigned to quadruplicate groups of fish (initial body weight 19.1 ±â€¯0.01 g). Results indicated that significantly higher specific growth rate (SGR) and lower feed conversion rate (FCR) were obtained in fish fed 1% HY diet than that of fish fed 0% HY diet (P < 0.05). Fish fed 0.25% HY diet showed the lowest value of hepatopancreas somatic indices (HSI) and significantly lower than that of fish fed 0% HY diet (P < 0.05). Meanwhile, protein and ash in the whole-body content of fish fed 1% HY diet was significantly higher than that of fish fed 0%-0.5% HY diets. Serum immunological parameters showed that the lysozyme (LZM) activity and Complement C3 content were significantly increased by dietary supplementation of 0.5%-1% HY (P < 0.05). However, dietary supplementation with 0.125%-1% HY significantly decreased the activity of myeloperoxidase (MPO) (P < 0.05). Antioxidant status in serum and liver was significantly enhanced by dietary supplementation of 0.25%-1% HY through the remarkably improved superoxide dismutase (SOD) activity both in serum and liver, the raised total antioxidative capacity (T-AOC) of serum as well as the notably reduced malondialdehyde (MDA) content in the liver (P < 0.05). However, T-AOC in the liver was not significantly influenced among all diet treatments (P > 0.05). Villi height and intraepithelial lymphocytes (IEFs) of mid-intestine were significantly higher in fish fed 0.5%-1% HY diets (P < 0.05). The challenge test demonstrated the enhanced protection against Streptococcus iniae strain by the obtained higher cumulative survival rate. In conclusion, dietary supplementation of 1% HY could maintain the better growth performance, nutrient composition as well as immune response and antioxidant capacity for juvenile Nile tilapia.

Bioprospecting microbes for single-cell oil production from starchy wastes.

Production of lipid from oleaginous yeast using starch as a carbon source is not a common practice; therefore, the purpose of this investigation was to explore the capability of starch assimilating microbes to produce oil, which was determined in terms of biomass weight, productivity, and lipid yield. Saccharomyces pastorianus, Rhodotorula mucilaginosa, Rhodotorula glutinis, and fungal isolate Ganoderma wiiroense were screened for the key parameters. The optimization was also performed by one-factor-at-a-time approach. Considering the specific yield of lipid and cell dry weight yield, R. glutinis and R. mucilaginosa showed superiority over other strains. G. wiiroense, a new isolate, would also be a promising strain for starch waste utilization in terms of extracellular and intracellular specific yield of lipids. Extracellular specific yield of lipid was highest in R. glutinis culture (0.025 g g-1 of biomass) followed by R. mucilaginosa (0.022 g g-1 of biomass) and G. wiiroense (0.020 g g-1 of biomass). Intracellular lipid was again highest in R. glutinis (0.048 g g-1 of biomass). The most prominent fatty acid methyl esters among the lipid as detected by GC-MS were saturated lipids mainly octadecanoic acid, tetradecanoate, and hexadecanoate. Extracellular lipid produced on starch substrate waste would be a cost-effective alternative for energy-intensive extraction process in biodiesel industry.

Characterization, antioxidativity, and anti-carcinoma activity of exopolysaccharide extract from Rhodotorula mucilaginosa CICC 33013.

The water-soluble exopolysaccharide REPS2-A was isolated and characterized from R. mucilaginosa CICC 33013. REPS2-A was composed of galactose, arabinose, glucose, and mannose at a molar ratio of 63.1:0.2:18.3:18.3, respectively, with a molecular weight of 7.125×106Da. Based on FT-IR, NMR, and methylation analysis, REPS2-A was identified to be a highly branched polysaccharide with a backbone of (1→3)-linkedGal with Man, Gal, and Ara terminals. The branches were identified as (1→2)-linked Glc, (1→4)-linked Man, (1→3)-linked Glc, (1→4,6)-linked Man, and (1→2,3,4)-linked Ara. In addition, REPS2-A exhibited excellent free radical scavenging (DPPH, ABTS, and reducing power) and antitumor activities. These results indicate its activity against growth of the human hepatocarcinoma cell HepG2 with IC50 values of 1.0mg/mL, compared to lower cytotoxic effects on normal human hepatocyte cell L02. Studying the underlying mechanisms indicated that REPS2-A induced both dose- and time-dependent cell cycle arrest at the G1/S phase.

Probable fungemia por Rhodotorula mucilaginosa asociada a catéter venoso central en un paciente pediátrico: presentación de un caso / Probable fungemia by rhodotorula mucilaginosa associated to a central venous catheter in a pediatric pacient: a case report

Las levaduras del género Rhodotorula son patógenos oportunistas emergentes, especialmente en pacientes inmunocomprometidos. Se presenta el caso de un niño de 9 años con sarcoma de Ewing en tratamiento con quimioterapia que cursó con una probable fungemia por Rhodotorula mucilaginosa. Se identificaron varios factores de riesgo tales como la presencia de un catéter venoso central (CVC) y una neoplasia maligna sólida. El diagnóstico se realizó a través de un hemocultivo de una rama del CVC. Nuestra cepa fue identificada como R. Mucilaginosa por morfofisiología y pruebas bioquimicas. El éxito terapeutico se basó en el retiro del CVC y en el tratamiento con anfotericina B desoxicolato como primera alternativa.

Yeasts from Rhodotorula genus are opportunistic pathogen that emerge especially in immunocompromised patients. We report a case of a 9-years-old boy, he developed an Ewing’s sarcoma that was treated with chemotherapy an underwent with problable fungemia by Rhodotorula mucilaginosa. Several risk factors were identified such as presence of a central venous catheter (CVC) and a solid malignant neoplasm. The diagnosis was made by blood culture of a branch of the CVC. Our isolated was identified as R. mucilaginosa by morphofisiology and biochemical test. The therapy did success based on withdrawal of CVC and treatment with amphotericin B deoxycholate as the first alternative.

Lipids of Rhodotorula mucilaginosa IIPL32 with biodiesel potential: Oil yield, fatty acid profile, fuel properties.

This study analyzes the single cell oil (SCO), fatty acid profile, and biodiesel fuel properties of the yeast Rhodotorula mucilaginosa IIPL32 grown on the pentose fraction of acid pre-treated sugarcane bagasse as a carbon source. The yeast biomass from nitrogen limiting culture conditions (15.3 g L-1 ) was able to give the SCO yield of 0.17 g g-1 of xylose consumed. Acid digestion, cryo-pulverization, direct in situ transesterification, and microwave assisted techniques were evaluated in comparison to the Soxhlet extraction for the total intracellular yeast lipid recovery. The significant differences were observed among the SCO yield of different methods and the in situ transesterification stood out most for effective yeast lipid recovery generating 97.23 mg lipid as FAME per gram dry biomass. The method was fast and consumed lesser solvent with greater FAME yield while accessing most cellular fatty acids present. The yeast lipids showed the major presence of monounsaturated fatty esters (35-55%; 18:1, 16:1) suitable for better ignition quality, oxidative stability, and cold-flow properties of the biodiesel. Analyzed fuel properties (density, kinematic viscosity, cetane number) of the yeast oil were in good agreement with international biodiesel standards. The sugarcane bagasse-derived xylose and the consolidated comparative assessment of lab scale SCO recovery methods highlight the necessity for careful substrate choice and validation of analytical method in yeast oil research. The use of less toxic co-solvents together with solvent recovery and recycling would help improve process economics for sustainable production of biodiesel from the hemicellulosic fraction of cheap renewable sources.

Some biological activities of pigments extracted from Micrococcus roseus (PTCC 1411) and Rhodotorula glutinis (PTCC 5257).

The importance of replacing synthetic pigments with natural types is increasing day by day in the food industry due to the harmful effects of some synthetic pigments. Microorganisms are a major source of natural pigments, which nowadays have attracted the attention of researchers. In this study, carotenoid pigments were produced by Micrococcus roseus and Rhodotorula glutinis, and some of their biological properties such as antimicrobial, antioxidant, anticancer, and anti-inflammatory activities were evaluated. Given the results, bacteria, especially gram-positive bacteria, had higher sensitivity to the pigments extracted from M. roseus (PEM) and R. glutinis (PER) compared to molds so that Bacillus cereus and Alternaria citri had the highest and the lowest sensitivity, respectively. PER showed a higher antioxidant activity compared with PEM in the various methods of measuring antioxidant activity. In vitro and in vivo anti-tumor-promoting activities of PER were measured significantly more than PEM (P <0.05). Both pigment extracts remarkably inhibited the 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation, so that ID50 (50% inhibitory dose) of PEM and PER were 0.22 and 0.09 mg/ear, respectively.

Proteomic analysis of an environmental isolate of Rhodotorula mucilaginosa after arsenic and cadmium challenge: Identification of a protein expression signature for heavy metal exposure.

UNLABELLED: A metal-resistant Rhodotorula mucilaginosa strain was isolated from an industrial wastewater. Effects on reduced/oxidized glutathione (GSSG/GSH), antioxidant enzymes and proteome were assessed on metal challenge (100mg/L). Increased GSH (mM/g) was found with CdCl2 (18.43±3.34), NaAsO2 (14.76±2.14), CuSO4 (14.73±2.49), and Pb(NO3)2 (15.74±5.3) versus control (7.67±0.95). GSH:GSSG ratio decreased with CdCl2, NaAsO2, and Pb(NO3)2 but not with CuSO4 and cysteine-containing protein levels increased with CdCl2 and NaAsO2. NaAsO2 exposure enhanced glutathione transferase activity but this decreased with CdCl2. Both metals significantly increased glutathione reductase and catalase activities. Metabolism-dependent uptake of Cd and As (12-day exposure) of approximately 65mg/g was observed in live cells with greater cell surface interaction for As compared to Cd. A particular role for arsenic oxidase in As resistance was identified. One dimensional electrophoresis revealed higher oxidation of protein thiols in response to NaAsO2 than to CdCl2. Two dimensional electrophoresis showed altered abundance of some proteins on metal treatment. Selected spots were excised for mass spectrometry and seven proteins identified. Under oxidative stress conditions, xylose reductase, putative chitin deacetylase, 20S proteasome subunit, eukaryotic translation elongation factor 2, valine-tRNA ligase and a metabolic enzyme F0F1 ATP synthase alpha subunit were all expressed as well as a unique hypothetical protein. These may comprise a protein expression signature for metal-induced oxidation in this yeast. SIGNIFICANCE: Fungi are of widespread importance in agriculture, biodegradation and often show extensive tolerance to heavy metals. This makes them of interest from the perspective of bioremediation. In this study an environmental isolate of R. mucilaginosa showing extensive tolerance of a panel of heavy metals, in particular cadmium and arsenic, was studied. Several biochemical parameters such as activity of antioxidant enzymes, status of reduced and oxidized glutathione and thiols associated with proteins were all found to be affected by metal exposure. A detailed analysis with arsenic and cadmium pointed to a particular role for arsenic oxidase in arsenic bioaccumulation and tolerance. This is the first time this has been reported in R. mucilaginosa, and suggests that this isolate may have potential in biosorption of these metals in the environment. Proteomic analysis revealed that seven proteins with a variety of roles - ATP synthesis, protein degradation/synthesis, and metabolism of xylose and chitin - were differentially affected by metal exposure in a manner consistent with oxidative stress. These may therefore represent a protein expression signature for exposure to cadmium and arsenic.

Yeast-based Biochemical Oxygen Demand Sensors Using Gold-modified Boron-doped Diamond Electrodes.

A gold nanoparticle modified boron-doped diamond electrode was developed as a transducer for biochemical oxygen demand (BOD) measurements. Rhodotorula mucilaginosa UICC Y-181 was immobilized in a sodium alginate matrix, and used as a biosensing agent. Cyclic voltammetry was applied to study the oxygen reduction reaction at the electrode, while amperometry was employed to detect oxygen, which was not consumed by the microorganisms. The optimum waiting time of 25 min was observed using 1-mm thickness of yeast film. A comparison against the system with free yeast cells shows less sensitivity of the current responses with a linear dynamic range (R(2) = 0.99) of from 0.10 mM to 0.90 mM glucose (equivalent to 10 - 90 mg/L BOD) with an estimated limit of detection of 1.90 mg/L BOD. However, a better stability of the current responses could be achieved with an RSD of 3.35%. Moreover, less influence from the presence of copper ions was observed. The results indicate that the yeast-immobilized BOD sensors is more suitable to be applied in a real condition.

The radiation resistance and cobalt biosorption activity of yeast strains isolated from the Lanyu low-level radioactive waste repository in Taiwan.

The ubiquitous nature of microbes has made them the pioneers in radionuclides adsorption and transport. In this study, the radiation resistance and nuclide biosorption capacity of microbes isolated from the Lanyu low-level radioactive waste (LLRW) repository in Taiwan was assessed, the evaluation of the possibility of using the isolated strain as biosorbents for (60)Co and Co (II) from contaminated aqueous solution and the potential impact on radionuclides release. The microbial content of solidified waste and broken fragments of containers at the Lanyu LLRW repository reached 10(5) CFU/g. Two yeast strains, Candida guilliermondii (CT1) and Rhodotorula calyptogenae (RT1) were isolated. The radiation dose necessary to reduce the microbial count by one log cycle of CT1 and RT1 was 2.1 and 0.8 kGy, respectively. Both CT1 and RT1 can grow under a radiation field with dose rate of 6.8 Gy/h, about 100 times higher than that on the surface of the LLRW container in Lanyu repository. CT1 and RT1 had the maximum (60)Co biosorption efficiency of 99.7 ± 0.1% and 98.3 ± 0.2%, respectively in (60)Co aqueous solution (700 Bq/mL), and the (60)Co could stably retained for more than 30 days in CT 1. Nearly all of the Co was absorbed and reached equilibrium within 1 h by CT1 and RT1 in the 10 µg/g Co (II) aqueous solution. Biosorption efficiency test showed almost all of the Co (II) was adsorbed by CT1 in 20 µg/g Co (II) aqueous solution, the efficiency of biosorption by RT1 in 10 µg/g of Co (II) was lower. The maximum Co (II) sorption capacity of CT1 and RT1 was 5324.0 ± 349.0 µg/g (dry wt) and 3737.6 ± 86.5 µg/g (dry wt), respectively, in the 20 µg/g Co (II) aqueous solution. Experimental results show that microbial activity was high in the Lanyu LLRW repository in Taiwan. Two isolated yeast strains, CT1 and RT1 have high potential for use as biosorbents for (60)Co and Co (II) from contaminated aqueous solution, on the other hand, but may have the impact on radionuclides release from LLRW repository.

Enhanced biocontrol activity of Rhodotorula mucilaginosa cultured in media containing chitosan against postharvest diseases in strawberries: possible mechanisms underlying the effect.

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.

Microbial metabolism. Part 11. Metabolites of flutamide.

The yeast culture, Rhodotorula mucilaginosa (ATCC 20129) transformed flutamide (1) to three metabolites: 4-nitro-3-(trifluoromethyl)aniline (2), 2-methyl-N-[4-amino-3-(trifloromethyl)phenyl]propanamide (3) and N-[4-amino-3-(trifluoromethyl)phenyl]acetamide (4). The structures were established by spectroscopic methods.

Cadmium-resistance in growing Rhodotorula sp. Y11.

The uptake of cadmium and responses to this metal were studied in growing Rhodotorula sp. Y11. In presence of cadmium, Y11 showed a similar lag phase with decreased mu(max) in comparison to the control cultures in the absence of cadmium. Different changes in contents of cell elemental composition (carotenoids, total protein, total soluble sugar, and phosphate content) were observed under cadmium pressure. Growing Rhodotorula sp. Y11 took up cadmium in a biphasic mode, involving an initial energy-independent biosorption to the cell surface, followed by a slower energy-dependent intracellular accumulation. In the presence of metabolic inhibitors, intracellular cadmium uptake of growing Y11 was significantly influenced.

L-asparaginase: a promising chemotherapeutic agent.

This article comprises detailed information about L-asparaginase, encompassing topics such as microbial and plant sources of L-asparaginase, treatment with L-asparaginase, mechanism of action of L-asparaginase, production, purification, properties, expression and characteristics of l-asparaginase along with information about studies on the structure of L-asparaginase. Although L-asparaginase has been reviewed by Savitri and Azmi (2003), our effort has been to include recent and updated information about the enzyme covering new aspects such as structural modification and immobilization of L-asparaginase, recombinant L-asparaginase, resistance to L-asparaginase, methods of assay of L-asparagine and L-asparaginase activity using the biosensor approach, L-asparaginase activity in soil and the factors affecting it. Also, side-effects of L-asparaginase treatment in acute lymphoblastic leukemia (ALL) have been discussed in the current review. L-asparaginase has been and is still one of the most widely studied therapeutic enzymes by researchers and scientists worldwide.