Advances in gene editing and natural product synthesis of Rhodotorula toruloides / 生物工程学报

Rhodotorula toruloides is a non-conventional red yeast that can synthesize various carotenoids and lipids. It can utilize a variety of cost-effective raw materials, tolerate and assimilate toxic inhibitors in lignocellulosic hydrolysate. At present, it is widely investigated for the production of microbial lipids, terpenes, high-value enzymes, sugar alcohols and polyketides. Given its broad industrial application prospects, researchers have carried out multi-dimensional theoretical and technological exploration, including research on genomics, transcriptomics, proteomics and genetic operation platform. Here we review the recent progress in metabolic engineering and natural product synthesis of R. toruloides, and prospect the challenges and possible solutions in the construction of R. toruloides cell factory.

Rhodotorula fungemia in a patient with acute lymphoblastic leukemia / Fungemia de Rhodotorula em paciente com leucemia linfoblástica aguda / Fungemia por Rhodotorula en un paciente con leucemia linfoblástica aguda

Objectives: Rhodotorula is an environmental yeast that belongs to Basidiomycota Phylum. Rhodotorula species are ubiquitous in nature, can be found in soil and freshwater. Immunocompromised patients can develop Rhodotorulosis due to wide-ranging exposure to Rhodotorula in the hospital environment. Case Discussion: The patient was a 3-year-old male with a diagnosis of Pro B-Acute Lymphoblastic Leukemia (ALL). He was admitted to the hospital with complaints of malaise, fatigue, weight loss, and diarrhea between courses of chemotherapy. Rhodotorula was isolated from the patient's blood culture obtained during the elevation of temperature. After 14 days of amphotericin B treatment, clinical situation of the patient was improved and he was discharged. Conclusion: Rhodotorula spp. as a rare yet emerging pathogen, often presents as fever of unknown etiology resistant to antibacterial treatment and can be associated with fungemia and other severe complications.(AU)

Objetivos: Rhodotorula é uma levedura ambiental que pertence ao filo Basidiomycota. As espécies de Rhodotorula são onipresentes na natureza, podem ser encontradas no solo e na água doce. Pacientes imunocomprometidos podem desenvolver rodotorulose devido à ampla exposição a Rhodotorula no ambiente hospitalar. Descrição do caso: O paciente era uma criança de 3 anos de idade com diagnóstico de Leucemia Linfoblástica Aguda Pro B (LLA). O paciente deu entrada no hospital com queixas de mal-estar, cansaço, perda de peso e diarreia entre os ciclos de quimioterapia. A Rhodotorula foi isolada da hemocultura do paciente obtida durante a elevação da temperatura. Após 14 dias de tratamento com anfotericina B, a situação clínica do paciente melhorou e o paciente recebeu alta. Conclusão: Rhodotorula spp. como um patógeno raro, porém emergente, frequentemente se apresenta como febre de etiologia desconhecida resistente ao tratamento antibacteriano e pode estar associada a fungemia e outras complicações graves.(AU)

Objetivos: Rhodotorula es una levadura ambiental que pertenece al filo Basidiomycota. Las especies de Rhodotorula son ubicuas en la naturaleza, se pueden encontrar en el suelo y en agua dulce. Los pacientes inmunodeprimidos pueden desarrollar Rhodotorulosis debido a una amplia exposición a Rhodotorula en el entorno hospitalario. Descripción del caso: El paciente era un niño de 3 años con diagnóstico de leucemia linfoblástica aguda Pro B (LLA). El paciente ingresó en el hospital con quejas de malestar, fatiga, pérdida de peso y diarrea entre ciclos de quimioterapia. Se aisló Rhodotorula del hemocultivo del paciente que se obtuvo durante la elevación de la temperatura. Después de 14 días de tratamiento con anfotericina B, la situación clínica del paciente mejoró y fue dado de alta. Conclusión: Rhodotorula spp. como patógeno poco común pero emergente, a menudo se presenta como fiebre de etiología desconocida resistente al tratamiento antibacteriano y puede asociarse con fungemia y otras complicaciones graves.(AU)

Avaliação da interação entre leveduras isoladas de kombucha e bactérias probióticas / Evaluation of the interaction between isolated kombucha yeasts and probiotic bacteria

Um dos maiores desafios no desenvolvimento de produtos probióticos é entender como os microrganismos interagem entre si e com o hospedeiro. Quando falamos em alimentos fermentados tradicionais, este obstáculo aumenta porque a matriz alimentar já possui um microbioma intrínseco. No entanto, também é conhecido que muitos microrganismos podem interagir e cooperar para sobreviver quando condições de estresse são encontradas. Assim, o objetivo deste trabalho foi isolar leveduras de quatro diferentes kombuchas em distintos momentos fermentativos e verificar a influência que leveduras isoladas de kombucha têm na manutenção da viabilidade da bactéria probiótica Bifidobacterium animalis subsp. lactis HN019 em condições de aerobiose. Meyerozyma guilliermondii, Candida albicans, Rhodotorula mucilaginosa e Pichia membranifaciens foram leveduras encontradas nas kombuchas, das quais as duas últimas favoreceram a manutenção da alta viabilidade de HN019 em cocultura por 14 dias. Observou-se a viabilidade da bactéria acima de 9 log ao longo de todo o experimento, o que não foi observado em monocultura. Ademais, utilizou-se de análise de autoagregação, hidrofobicidade, atividade enzimática de proteases e fosfolipases das leveuras para analisar seu potencial patogênico. Observou-se que R. mucilaginosa demonstrou características semelhantes à Saccharomyces cerevisiae subsp. boulardii, e sua interação benéfica com HN019 reforça a possibilidade de que esta levedura seja uma chave para a inserção da bactéria em uma kombucha probiótica. Análises metabólicas foram realizadas e encontrou-se uma vasta diversidade de dipeptídeos, principalmente os compostos de prolina, durante a cocultura da bactéria com as leveduras. Tais dipeptídeos apresentam importantes mecanismos de ação no controle biológico e quorum sensing de bactérias e leveduras, e supostamente regulam a manutenção das relações mutualísticas entre ambos microrganismo

One of the biggest challenges in the development of probiotic products is to understand how microorganisms interact with each other and with the host. When we talk about traditional fermented foods, this obstacle increases because the food matrix already has an intrinsic microbiome. However, it is also known that many microorganisms can interact and cooperate to survive when stressful situations are encountered. Thus, the objective of this work was to isolate yeasts from four different kombuchas at different fermentation times and to verify the influence that yeasts isolated from kombucha have on maintaining the viability of the probiotic bacterium Bifidobacterium animalis subsp. lactis HN019 under aerobic conditions. Meyerozyma guilliermondii, Candida albicans, Rhodotorula mucilaginosa and Pichia membranifaciens were yeasts found in kombuchas, of which the last two favored the maintenance of HN019 high viability in co-culture for 14 days. Bacteria viability above 9 log was observed throughout the experiment, which was not observed in monoculture. In addition, analysis of autoaggregation, hydrophobicity, enzyme activity of proteases and phospholipases of yeasts was used to analyze their pathogenic potential. It was observed that R. mucilaginosa demonstrated characteristics similar to Saccharomyces cerevisiae subsp. boulardii, and its beneficial interaction with HN019 reinforces the possibility that this yeast is a key to the insertion of the bacterium in a probiotic kombucha. Metabolic analysis were performed and a wide diversity of dipeptides, mainly proline-based, was found during the co-culture of the bacteria with the yeasts. Such dipeptides have important mechanisms of action in the biological control and quorum sensing of bacteria and yeast, and supposedly regulate the maintenance of mutualistic relationships between both microorganism

Rastreio de leveduras patogênicas isoladas de fezes de pombos no Distrito Federal-Pombos: propagadores de fungos patogênicos? / Screening for pathogenic yeasts isolated from pigeon droppings in the Federal District-Pigeons: propagators of pathogenic fungi? / Detección de levaduras patógenas aisladas de excrementos de paloma en el Distrito Federal-Palomas: ¿propagadores de hongos patógenos?

Objetivo: Investigar a presença de fungos patogênicos isolados a partir de amostras de fezes de pombos, em locais de atenção a pacientes imunocomprometidos no DF. Método: As amostras foram coletadas em hospitais onde se oferta atendimento a pacientes HIV/AIDS e que tenha uma presença massiva de pombos. Colônias de leveduras foram previamente selecionados em meio Ágar Sabouraud Dextrose acrescido de cloranfenicol, seguindo-se com análise microscópica das estruturas leveduriformes. Colônias de leveduras com suspeita de pertencerem ao gênero Candida spp. ou Cryptococcus sp., foram inoculadas no meio Ágar Cromogênico para identificação das espécies de Candida e em meio Ágar quimicamente definido para indução dos fenótipos de virulência característicos de Cryptococcus sp. Resultados: 100% das amostras analisadas apresentaram crescimento de leveduras do gênero Candida spp. e Rhodotorula sp. No meio Ágar Cromogênico foram identificadas nas amostras C. krusei em 75%; C. tropicalis em 50% e C. glabrata em 15%. Em 15% das amostras foi identificado leveduras do gênero Cryptococcus sp. Conclusão: Dados deste estudo sugerem que fezes de pombo podem estar dispersando leveduras patogênicas e contribuindo com a incidência de infecções fúngicas no DF.

Objective: To investigate the presence of pathogenic fungi isolated from pigeon stool samples, in places of care for immunocompromised patients in the Federal District. Method: The samples were collected in hospitals where care is offered to HIV / AIDS patients and which has a massive presence of pigeons. Yeast colonies were previously selected on Sabouraud Dextrose Agar plus chloramphenicol, followed by microscopic analysis of the yeast structures. Yeast colonies suspected of belonging to the genus Candida spp. or Cryptococcus sp., were inoculated in the Chromogenic Agar medium to identify Candida species and in chemically defined Agar medium to induce the virulence phenotypes characteristic of Cryptococcus sp. Results: 100% of the analyzed samples showed growth of yeasts of the genus Candida spp. and Rhodotorula sp. In the chromogenic agar medium, 75% were identified in C. krusei samples; C. tropicalis in 50% and C. glabrata in 15%. In 15% of the samples, yeasts of the genus Cryptococcus sp. Conclusion: Data from this study suggest that pigeon feces may be dispersing pathogenic yeasts and contributing to the incidence of fungal infections in DF

Objetivo: Investigar la presencia de hongos patógenos aislados de muestras de heces de palomas, en los lugares de atención a pacientes inmunodeprimidos del Distrito Federal. Método: Las muestras se recolectaron en hospitales donde se brinda atención a pacientes con VIH / SIDA y que tiene una presencia masiva de palomas. Las colonias de levadura se seleccionaron previamente en Sabouraud Dextrose Agar más cloranfenicol, seguido de un análisis microscópico de las estructuras de la levadura. Las colonias de levaduras sospechosas de pertenecer al género Candida spp. o Cryptococcus sp., se inocularon en medio de agar cromogénico para identificar especies de Candida y en medio de agar químicamente definido para inducir los fenotipos de virulencia característicos de Cryptococcus sp. Resultados: el 100% de las muestras analizadas presentó crecimiento de levaduras del género Candida spp. y Rhodotorula sp. En el medio agar cromogénico, el 75% se identificó en muestras de C. krusei; C. tropicalis en 50% y C. glabrata en 15%. En el 15% de las muestras, levaduras del género Cryptococcus sp. Conclusión: Los datos de este estudio sugieren que las heces de las palomas pueden estar dispersando levaduras patógenas y contribuyendo a la incidencia de infecciones fúngicas en el DF.

Directed evolution of tyrosine ammonia-lyase to improve the production of p-coumaric acid in Escherichia coli / 生物工程学报

p-coumaric acid is an important natural phenolic compound with a variety of pharmacological activities, and also a precursor for the biosynthesis of many natural compounds. It is widely used in foods, cosmetics and medicines. Compared with the chemical synthesis and plant extraction, microbial production of p-coumaric acid has many advantages, such as energy saving and emission reduction. However, the yield of p-coumaric acid by microbial synthesis is too low to meet the requirements of large-scale industrial production. Here, to further improve p-coumaric acid production, the directed evolution of tyrosine ammonia lyase (TAL) encoded by Rhodotorula glutinis tal gene was conducted, and a high-throughput screening method was established to screen the mutant library for improve the property of TAL. A mutant with a doubled TAL catalytic activity was screened from about 10,000 colonies of the mutant library. There were three mutational amino acid sites in this TAL, namely S9Y, A11N, and E518A. It was further verified by a single point saturation mutation. When S9 was mutated to Y, I or N, or A11 was mutated to N, T or Y, the catalytic activity of TAL increased by more than 1-fold. Through combinatorial mutation of three types of mutations at the S9 and A11, the TAL catalytic activity of S9Y/A11N or S9N/A11Y mutants were significantly higher than that of other mutants. Then, the plasmid containing S9N/A11Y mutant was transformed into CP032, a tyrosine-producing E. coli strain. The engineered strain produced 394.2 mg/L p-coumaric acid, which is 2.2-fold higher than that of the control strain, via shake flask fermentation at 48 h. This work provides a new insight for the biosynthesis study of p-coumaric acid.

Infección por Rhodotorula rubra en el lactante con leucemia linfoblástica aguda. Reporte de un caso / Rhodotorula rubra infection in infants with acute lymphoblastic leukemia. Case report

Rhodotorula especies (spp.) son levaduras comensales de la familia Sporidiobolaceae. Rhodotorula rubra es un patógeno oportunista y emergente que tiene la habilidad de colonizar e infectar a los pacientes susceptibles como son los que padecen de enfermedades hematológicas malignas, y está asociado con el uso de catéteres venosos centrales. Hay pocos reportes de casos en niños inmunocomprometidos. Presentamos el caso de una paciente lactante con diagnóstico de leucemia linfoblástica aguda (LLA) B común, que presentó infección fúngica por Rhodotorula rubra.

Rhodotorula species (spp.) are commensal yeasts of the family Sporidiobolaceae. Rhodotorula rubra is an opportunistic and emerging pathogen with the ability to colonize and infect susceptible patients like patients with malignant haematological diseases and it is associated with the use of central venous catheters. Only a few reports have linked found in immunocompromised children. In this article we present the case report of a lactating patient with a diagnosis of common acute lymphoblastic leukemia (B), who presented a fungal infection by Rhodotorula rubra.

Process conditions for a rapid in situ transesterification for biodiesel production from oleaginous yeasts

BACKGROUND: Microbial oils produced by diverse microorganisms are being considered as alternative sources of triglycerides for biodiesel production. However, the standalone production of biodiesel from microorganisms is not currently economically feasible. In case of yeasts, the use of low-value nutrient sources in microbial production and the implementation of cost-efficient downstream processes could reduce costs and make microbial lipids competitive with other commodity-type oils in biodiesel production. Industrial biodiesel synthesis from oleaginous seeds is currently based on a multistep process. However, a simple process called in situ transesterification (ISTE), which takes place within the biomass without a previous lipid extraction step, is receiving increasing interest. In this work, the optimal conditions for an ISTE process to obtain biodiesel from previously selected oleaginous yeast (Rhodotorula graminis S1/S2) were defined using the response surface methodology (RSM). RESULTS: Using the RSM approach, the optimal conditions for the maximum yield with minimum reaction time included a methanol-to-biomass ratio of 60:1, 0.4 M H2SO4, and incubation at 70°C for 3 h. The optimized in situ process yield was significantly higher (123%) than that obtained with a two-step method in which fatty acids from saponifiable lipids were first extracted and then esterified with methanol. The composition of the fatty acid methyl ester mixture obtained from R. graminis S1/S2 by ISTE met Uruguayan standards for biodiesel. CONCLUSION: The characteristics achieved by the optimized method make microbial oil a potential alternative for biodiesel production from yeast at an industrial scale.

Carotenoid production in sugarcane juice and synthetic media supplemented with nutrients by Rhodotorula rubra l02

ABSTRACT In order for the use of biological carotenoids to become feasible, it is necessary to have adequate low cost sources and improved methods of cultivation. The aim of this study was to evaluate the effect of supplementation with nitrogen, phosphorus, zinc, and magnesium, on the biomass and carotenoid volumetric production by yeast Rhodotorula rubra L02 using a complex medium (sugarcane juice) and synthetic media (sucrose and maltose) as substrates. The experimental design used for each substrate was randomized in blocks with 16 treatments and 3 repetitions. The treatments were compound for 15 different combinations of nutrients (N; Mg; Zn; P, N + Mg; N + Zn; N + P; Mg + Zn; Mg + P; Zn + P; N + P + Zn; N + P + Mg; N + Zn + Mg; P + Zn + Mg; N + Zn + Mg + P) alone and combined, and a control. The results were submitted to analysis of variance and Tukey test at 5% significance level. Among the treatments evaluated, the highest production of dry biomass, with both maltose and sucrose, was observed for Mg (1.60 g/L and 1.94 g/L, respectively). Additionally, another treatment that stood out in terms of biomass production was the control treatment with maltose (1.54 g/L). After the incubation time, killer activity was not observed since there was no formation of inhibition halo around the L02 yeast.

Dermatite fúngica associada à Rhodotorula glutinis em cão - Canis familiaris ): relato de caso / Fungal dermatitis associated to Rhodotorula glutinis in dog (Canis familiaris): case report

O fungo Rhodotorula sp. era considerado como não patogênico, mas, com o aumento de casos de humanos imunossuprimidos nas últimas duas décadas, as espécies R. mucilaginosa, R. glutinis e R. minuta se tornaram agentes potencialmente patogênicos. Poucos relatos clínicos veterinários associados à Rhodotorula spp. foram descritos, e o objetivo deste trabalho foi descrever um caso de dermatite fúngica causada por R. glutinis em cão imunossuprimido devido à leishmaniose visceral e osteossarcoma, na cidade de Cuiabá-Mato Grosso. Um cão, macho, 11 anos, sem raça definida, foi trazido ao Hospital Veterinário apresentando lesões de pele com diagnóstico de dermatofitose e foi prescrito tratamento tópico à base de óleo de melaleuca, sem melhora após um mês de tratamento. O animal retornou ao Hospital Veterinário com hemorragia na região lesionada da cauda, e foi realizada biópsia para exames microbiológico e histopatológico. Nas análises microbiológica e histopatológica, foi isolada uma levedura e detectada a presença de estrutura semelhante a leveduras na coloração de prata, respectivamente. A levedura isolada foi identificada como R. glutinis por meio do sequenciamento do DNA. Um novo tratamento foi instituído, sem melhora do quadro clínico. O animal foi diagnosticado também com leishmaniose e osteossarcoma, provavelmente ocasionando a immunossupressão, e seu quadro evoluiu a óbito.(AU)

The fungi Rhodotorula sp was considered nonpathogenic, but with the increase of immunosuppressed humans in the last two decades, the species R. mucilaginosa, R. glutinis and R. minuta became potentially pathogenic agents. There have been few veterinary clinical reports associated with Rhodotorula spp. and this work aims to describe the first case of fungal dermatitis caused by R. glutinis in immunosuppressed dog due to visceral leishmaniasis and osteosarcoma in the city of Cuiabá-Mato Grosso. An 11-year-old male mongrel dog was examined to the Veterinary Hospital with skin lesions and the diagnosis was dermatophytosis and the treatment was implemented with topical tea tree oil for one month, but the treatment failed. The animal returned to the Veterinary Hospital with bleeding in the injured area of the tail and biopsy was performed for microbiological and histopathology evaluation. In the microbiological and histopathological analysis, yeast was isolated and yeast-like structures in silver staining were observed, respectively. The isolated yeast was identified as R. glutinis by DNA sequencing. A new treatment was implemented without clinical improvement. The animal was diagnosed with leishmaniasis and osteosarcoma, which probably caused immunosuppression, and its clinical conditions evolved to death.(AU)

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.

Effect of initial pH of medium with potato wastewater and glycerol on protein, lipid and carotenoid biosynthesis by Rhodotorula glutinis

Background: Rhodotorula glutinis is capable of synthesizing numerous valuable metabolites with extensive potential industrial usage. This paper reports the effect of initial culture medium pH on growth and protein, lipid, and carotenoid biosynthesis by R. glutinis. Results: The highest biomass yield was obtained in media with pH 4.0­7.0, and the value after 72 h was 17.2­19.4 gd.w./L. An initial pH of the medium in the range of 4.0­7.0 has no significant effect on the protein (38.5­41.3 g/100 gd.w.), lipid (10.2­12.7 g/100 gd.w.), or carotenoid (191.7­202.9 µg/gd.w.) content in the biomass or on the profile of synthesized fatty acids and carotenoids. The whole pool of fatty acids was dominated by oleic (48.1­53.4%), linoleic (21.4­25.1%), and palmitic acids (13.0­15.8%). In these conditions, the yeast mainly synthesized torulene (43.5­47.7%) and ß-carotene (34.7­38.6%), whereas the contribution of torularhodin was only 12.1­16.8%. Cultivation in medium with initial pH 3.0 resulted in a reduction in growth (13.0 gd.w./L) and total carotenoid (115.8 µg/gd.w.), linoleic acid (11.5%), and torularhodin (4.5%) biosynthesis. Conclusion: The different values of initial pH of the culture medium with glycerol and deproteinized potato wastewater had a significant effect on the growth and protein, lipid, and carotenoid biosynthesis by R. glutinis.

Clinical Usefulness of PCR-REBA for Diagnosis of Onychomycosis / 대한의진균학회지

BACKGROUND: PCR-based reverse blot hybridization assay (PCR-REBA) has high sensitivity and specificity, can be performed directly on nail samples, is relatively cheaper than other molecular biologic methods, and is useful for diagnosing onychomycosis. OBJECTIVE: This study aims to compare the diagnostic efficacy of fungal culture and REBA Fungus-ID® which is a commercial PCR-REBA-based kit used for onychomycosis diagnosis. METHODS: Fifty nail samples were collected from 50 patients diagnosed with onychomycosis via direct microscopic examination using KOH preparation, and subjected to fungal culture and REBA Fungus-ID® test. RESULTS: The sensitivity of conventional fungal culture and REBA Fungus-ID® was 56% and 100%, respectively. In REBA Fungus-ID®, 43 of 50 samples were found to be infected with Trichophyton rubrum. Four of the remaining 7 samples were identified as infected with Trichophyton spp., one with Trichophyton mentagrophytes, and two revealed a panfungal DNA sequence. In fungal culture, 28 of 50 samples showed growth, of which 18 samples were identified as T. rubrum, 3 as Rhodotorula mucilaginosa, 3 as Cladosporium spp., 1 as Cyphellophora europaea, 1 as Penicillium cvjetkovicii, 1 as Lachnum soppittii, and 1 as non-dermatophytic mold. REBA Fungus-ID® and fungal culture were identical in 20 cases (40%). The non-dermatophytic fungi identified in fungal culture were considered contaminants. CONCLUSION: Nail specimens can be used directly for REBA Fungus-ID®, which has a high sensitivity for onychomycosis diagnosis. Therefore, it can be considered useful for diagnosis and identification of the causative organism in mixed infections like onychomycosis.

Interaction of Acidithiobacillus ferrooxidans, Rhizobium phaseoli and Rhodotorula sp. in bioleaching process based on Lotka-Volterra model

Background: Nowadays, leaching-ore bacteria, especially Acidithiobacillus ferrooxidans is widely used to retrieve heavy metals, many researches reflected that extra adding microorganism could promote bioleaching efficiency by different mechanisms, but few of them discussed the interaction between microorganisms and based on growth model. This study aimed to provide theoretical support for the collaborative bioleaching of multiple microorganisms by using the Lotka-Volterra (L-V) model. Results: This study investigated the interaction of Acidithiobacillus ferrooxidans, Rhizobium phaseoli,and Rhodotorula sp. Results showed that the individual growth of the three microorganisms fit the logistic curves. The environmental capacities of A. ferrooxidans, R. phaseoli, and Rhodotorula sp. were 1.88 x 109, 3.26 x 108, and 2.66 x 108 cells/mL, respectively. Co-bioleaching showed mutualism between A. ferrooxidans and R. phaseoli with mutualism coefficients of a =1.19and /3 = 0.31, respectively. The relationship between A. ferrooxidans and Rhodotorula sp. could be considered as commensalism. The commensalism coefficient y of the effect of Rhodotorula sp. on A. ferrooxidans was 2.45. The concentrations of A. ferrooxidans and R. phaseoli were 3.59 x 109 and 1.44 x 109 cells/mL in group E, respectively, as predicted by the model. The concentrations of A. ferrooxidans and Rhodotorula sp. were 2.38 x 109 and 2.66 x 108 cells/mL, respectively. The experimental peak values of the concentrations in microorganism groups E and F were detected on different days, but were quite close to the predicted values. Conclusion: The relationship among microorganisms during leaching could be described appropriately by Lotka-Volterra model between the initial and peak values. The relationship of A. ferrooxidans and R. phaseoli could be considered as mutualism, whereas, the relationship of A. ferrooxidans and R. phaseoli could be considered as commensalism.

Peritonitis fúngica por Rhodotorula mucilaginosa en una paciente en diálisis peritoneal automatizada: revisión de la literatura / Fungal peritonitis due to Rhodotorula mucilaginosa in a patient with automated peritoneal dialysis: literature review

Fungal peritonitis is a major complication of peritoneal dialysis associated with high mortality. Most survivors have a high rate of abandonment of peritoneal dialysis. We report a case of fungal peritonitis due to an unusual agent. An 83 year-old woman, with a history of type 2 diabetes mellitus and multiple episodes of bacterial peritonitis associated to technical flaws in the implementation of automated peritoneal dialysis, was admitted due to abdominal pain and cloudy peritoneal fluid. Rhodotorula mucilaginosa was identified in the peritoneal fluid by MALDI-TOF. She was treated with catheter removal and oral posaconazole for 14 days showing clinical resolution and non-recurrence.

La peritonitis fúngica es una complicación mayor de la diálisis peritoneal, con una alta mortalidad asociada y la mayoría de los sobrevivientes presentan una alta tasa de abandono de diálisis peritoneal como terapia de reemplazo renal. Se presenta un caso de peritonitis fúngica por un agente infrecuente. Mujer de 83 años, diabética con múltiples episodios de peritonitis bacteriana asociada a fallas técnicas en la ejecución de diálisis peritoneal automatizada, ingresa por cuadro clínico de dolor abdominal y líquido peritoneal turbio. Se confirmó la presencia de Rhodotorula mucilaginosa en líquido peritoneal mediante MALDI-TOF. Fue tratada con retiro del catéter y posaconazol oral por 14 días, presentando una evolución favorable.

Lipid synthesis by an acidic acid tolerant Rhodotorula glutinis / 生物工程学报

Acetic acid, as a main by-product generated in the pretreatment process of lignocellulose hydrolysis, significantly affects cell growth and lipid synthesis of oleaginous microorganisms. Therefore, we studied the tolerance of Rhodotorula glutinis to acetic acid and its lipid synthesis from substrate containing acetic acid. In the mixed sugar medium containing 6 g/L glucose and 44 g/L xylose, and supplemented with acetic acid, the cell growth was not:inhibited when the acetic acid concentration was below 10 g/L. Compared with the control, the biomass, lipid concentration and lipid content of R. glutinis increased 21.5%, 171% and 122% respectively when acetic acid concentration was 10 g/L. Furthermore, R. glutinis could accumulate lipid with acetate as the sole carbon source. Lipid concentration and lipid yield reached 3.20 g/L and 13% respectively with the initial acetic acid concentration of 25 g/L. The lipid composition was analyzed by gas chromatograph. The main composition of lipid produced with acetic acid was palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid, including 40.9% saturated fatty acids and 59.1% unsaturated fatty acids. The lipid composition was similar to that of plant oil, indicating that lipid from oleaginous yeast R. glutinis had potential as the feedstock of biodiesel production. These results demonstrated that a certain concentration of acetic acid need not to be removed in the detoxification process when using lignocelluloses hydrolysate to produce microbial lipid by R. glutinis.

Sepsis Due to Rhodotorula mucilaginosa in a Patient with Advanced Non-Small Cell Lung Cancer

Rhodotorula species are round to oval-shaped, multilateral budding, encapsulated yeasts that produce urease and do not ferment carbohydrates. Rhodotorula species form characteristic salmon-pink colored colonies owing to carotenoid pigment production. These yeasts form a part of the normal flora of moist skin and are found in the environment. Rhodotorula was traditionally considered a contaminant but is now progressively recognized as a human pathogen, especially in immunocompromised patients with central venous catheters. However, isolation of Rhodotorula species from blood has been very rarely reported in Korea. We report a case of sepsis due to Rhodotorula mucilaginosa infection in a patient who had received chemotherapy and supportive care for non-small cell lung cancer.

Biodegradation of deproteinized potato wastewater and glycerol during cultivation of Rhodotorula glutinis yeast

Background Deproteinized potato wastewater and glycerol are two by-products which are difficult to dispose. The objective of this study was to determine the ability of Rhodotorula glutinis to use glycerol and nitrogen compounds present in deproteinized potato wastewater and to evaluate the ability of simultaneous biodegradation of potato wastewater and glycerol via microbiological methods. Results It has been found that R. glutinis used glycerol and potato wastewater as a source of carbon and nitrogen, respectively. The highest degree of glycerol content (70.6%) reduction was found after cultivation of the investigated strain using a medium with 5% glycerol. In this medium, a significant reduction in the total protein content, estimated at 61%, was observed. The process of 72 h cultivation of yeast in a medium containing potato wastewater and 5% glycerol reduced the chemical oxygen demand (COD) more than 77%. Supplementation of media with high doses of glycerol (i.e. 20 and 25%) led to decreased metabolic activity in the yeast strain tested. Conclusion It has been found that there is a possibility of simultaneous biodegradation of potato wastewater and glycerol during the cultivation of R. glutinis.

Characterization of pectinase activity for enology from yeasts occurring in Argentine Bonarda grape

Pectinolytic enzymes are greatly important in winemaking due to their ability to degrade pectic polymers from grape, contributing to enhance process efficiency and wine quality. This study aimed to analyze the occurrence of pectinolytic yeasts during spontaneous fermentation of Argentine Bonarda grape, to select yeasts that produce extracellular pectinases and to characterize their pectinolytic activity under wine-like conditions. Isolated yeasts were grouped using PCR-DGGE and identified by partial sequencing of 26S rRNA gene. Isolates comprised 7 genera, with Aureobasidium pullulans as the most predominant pectinolytic species, followed by Rhodotorula dairenensis and Cryptococcus saitoi. No pectinolytic activity was detected among ascomycetous yeasts isolated on grapes and during fermentation, suggesting a low occurrence of pectinolytic yeast species in wine fermentation ecosystem. This is the first study reporting R. dairenensis and Cr. saitoi species with pectinolytic activity. R. dairenensis GM-15 produced pectinases that proved to be highly active at grape pH, at 12 °C, and under ethanol and SO₂ concentrations usually found in vinifications (pectinase activity around 1.1 U/mL). This strain also produced cellulase activity at 12 °C and pH 3.5, but did not produce β-glucosidase activity under these conditions. The strain showed encouraging enological properties for its potential use in low-temperature winemaking.

Clinical significance of the isolation of Candida species from hospitalized patients

In this study, we isolated and phenotypically identified 108 yeast strains from various clinical specimens collected from 100 hospitalized patients at three tertiary hospitals in São Luís-Maranhão, Brazil, from July to December 2010. The isolates were analyzed for their susceptibility to four of the most widely used antifungal agents in the surveyed hospitals, amphotericin B, fluconazole, 5-flucytosine and voriconazole. The species identified were Candida albicans (41.4%), Candida tropicalis (30.1%), C. glabrata (7.4%), Candida parapsilosis (5.5%), Candida krusei (4.6%), Cryptococcus neoformans (4.6%), Trichosporon spp. (3.7%), Candida norvegensis (0.9%), Rhodotorula glutinis (0.9%) and Pichia farinosa (0.9%). A higher isolation rate was observed in the following clinical specimens: urine (54 isolates; 50%), respiratory tract samples (21 isolates; 19.4%) and blood (20 isolates; 18.6%). Candida albicans isolates were 100% sensitive to all antifungal agents tested, whereas Candida krusei and Crytococcus neoformans displayed intermediate resistance to 5-flucytosine, with Minimal Inhibitory Concentration (MIC) values of 8 mg/mL and 16 mg/mL, respectively. Both strains were also S-DD to fluconazole with an MIC of 16 mg/mL. C. tropicalis was resistant to 5-flucytosine with an MIC of 32 μg/mL. This study demonstrates the importance of identifying the yeast species involved in community and nosocomial infections.

Controle pós-colheita da antracnose do pimentão pela levedura Rhodotorula glutinis / Post-harvest control anthracnose in pepper by yeast Rhodotorula glutinis

Considerando as perdas causadas em pós-colheita pela antracnose no pimentão e à ineficácia das medidas de controle atualmente utilizadas, este trabalho teve por objetivo estudar a potencialidade antagônica in vitro e in vivo de quinze isolados de leveduras à Colletotrichum sp., agente causal da antracnose em pimentão. Foi calculada a porcentagem de inibição do crescimento do fungo dos tratamentos em relação à testemunha nos testes in vitro e determinado o tamanho da área lesionada em frutos através da mensuração do comprimento da lesão em dois sentidos diametricamente opostos nos testes in vivo. As leveduras que obtiveram o melhor resultado no controle da antracnose foram identificadas através de características macroscópicas, microscópicas, fisiológicas, bioquímicas e por taxonomia molecular, sendo os isolados de levedura 13E e 13A1, os que obtiveram as melhores respostas no controle do fitopatógeno tanto in vitro quanto in vivo, identificados como pertencentes à espécie Rhodotorula glutinis.

Considering the losses caused by post-harvest anthracnose in sweet pepper chili and ineffectiveness of control measures currently used, this study had the objective of evaluate the antagonistic potential in vitro and in vivo of fifteen isolates of yeast to Colletotrichum sp., the causal agent of anthracnose on pepper. By calculating the percentage growth inhibition of the fungus treatment compared to the control tests in vitro and determining the size of lesions via the measurement of lesion length in both directions diametrically affixed in vivo tests. Yeasts who obtained the best result in controlling anthracnose were identified by characteristic macroscopic, microscopic, physiological, biochemical and molecular taxonomy. In this study, the yeast isolates 13E and 13A1, which obtained the best results in controlling the pathogen both in vitro and in vivo of the species Rhodotorula glutinis.