RESUMEN
The presence of red (RNA) and green (DNA) fluorescent material identifying nucleic acids in the chlamydospores of Candida albicans has been well documented. Red fluorescence in chlamydospores is relatively diffused and ranges from small spots, observed in hyphal cells, to the entire protoplasmic content. Green fluorescence is rarely visible in these structures and, when present it can be observed next to the plasmalemma. The initial percentage values of the two curves related to the cell counts of red fluorescence of the suspensor cells and chlamydospores showed remarkable differences between the two structures. About 54% of the chlamydospores showed red fluorescence compared to about 28% of the suspensor cells. It seems from the results obtained in this study that much RNA was produced and/or accumulated in the chlamydospores and suspensor cells, rather than in mycelium where red fluorescence was not observed. The results obtained sustain the hypothesis that a chlamydospore should he considered a fully functional cell that is morphologically and physiologically active and independent from mycelium.
Asunto(s)
Candida albicans/fisiología , Ácidos Nucleicos/metabolismo , Naranja de Acridina , Candida albicans/efectos de los fármacos , Candida albicans/metabolismo , Cicloheximida/farmacología , ADN de Hongos/metabolismo , Colorantes Fluorescentes , Microscopía Fluorescente , ARN de Hongos/metabolismo , Esporas Fúngicas/efectos de los fármacos , Esporas Fúngicas/metabolismoRESUMEN
By incubating starved and unstarved yeast cells in synthetic media with a pH of 4.5 or 6.7 at 37 degrees C the effect of a 3 hours' glucose starvation on germ-tube production by Candida albicans was evaluated. In addition the endocellular content of total carbohydrates, glycogen, trehalose and proteins after and before the starvation were dosed. The most interesting result was the overcoming of the pH-regulated dimorphism, thanks to the starvation treatment. In fact the starved cultures produced germ-tubes indifferently in neutral or acid media, whereas the filamentation of the unstarved cultures was more copious in pH 6.7 medium. The endocellular content of trehalose and protein was unchanged, whereas total carbohydrates and glycogen showed a shortage after the 3 hours' glucose starvation. The possible involvements of these metabolic changes in the regulation of dimorphic transition are discussed.
Asunto(s)
Candida albicans/crecimiento & desarrollo , Glucosa/metabolismo , Candida albicans/metabolismo , Reproducibilidad de los ResultadosRESUMEN
Se estudió un total de 90 casos de dermatofitosis durante 9 meses en la ciudad del Cusco (Perú) y alrededores. Los grupos de edad más comprometidos fueron de 1-10 y 11-20 años. La tiña más común fue tina capitis (13.3 por ciento) y tiña ungueal (11.1 por ciento). Se aislaron solamente 4 especies de dermatofitos: Microsporum canis (52.4 por ciento), Trichophyton mentagrophytes (35.7 por ciento), Trychophyton rubrun (9.5 por ciento) y Epidermophyton floccosum (2.4 por ciento). El clima seco, la baja temperatura y la gran altura no parecen afectar la proliferación y las reinfecciones por dermatofitos.
Asunto(s)
Trichophyton , Dermatomicosis , Arthrodermataceae , Epidermophyton , Microsporum , PerúRESUMEN
Candida albicans starved cells were incubated in minimal synthetic liquid media containing different concentrations of ammonium sulphate (0.00, 0.02, 0.05, 0.10, 0.03, 0.50 g/L). Culture growth was monitored by measuring daily the optical density and by evaluating RNA and protein cellular content after 48 and 96 hours from the inoculum. The environmental availability of ammonium ion influenced the biomass production, that was maximum when its concentration was 0.10 and 0.30 g/L. In addition, an effect on cell duplication time was observed, this was particularly evident when the (NH4)2SO4 concentration was 0.10 g/L. The protein content increased in relation to the increase of ammonium ion availability, with a peak in correspondence to 0.30 g/L and a drop when the greatest concentrations were employed. RNA production was inversely proportional in respect to protein production. The optimal range of ammonium sulphate concentration for C. albicans growth was 0.10-0.30 g/L; over these concentrations there was an inhibitory effect. The rate of the protein and RNA syntheses seems to indicate the growth phase and the nitrogen nutritional conditions of the cultures, respectively.
Asunto(s)
Sulfato de Amonio/metabolismo , Candida albicans/crecimiento & desarrollo , Candida albicans/metabolismo , Proteínas Fúngicas/biosíntesis , ARN de Hongos/biosíntesis , Sulfato de Amonio/toxicidad , Candida albicans/efectos de los fármacos , División Celular , Medios de CultivoRESUMEN
By using the fluorescent, DNA specific stain DAPI (4',6-diamidino-2-phenylindole) some microscopic observations of Candida albicans pseudomycelium and chlamydoconidia were performed. In this manner blue fluorescent dots were noted both in yeasts, psudomycelium and chlamydoconidia, so evidencing the presence of a nucleus in C. albicans chlamydoconidia.
Asunto(s)
Candida albicans/ultraestructura , Núcleo Celular , ADN de Hongos/análisis , Colorantes Fluorescentes , IndolesRESUMEN
A cohort of 69 children born to HIV-1 positive women was studied to evaluate types, prevalences and relationships to clinical stages of HIV-1-related oral lesions. In addition, relationships among C. albicans biotypes, clinical features of oral candidiasis and HIV-1 disease were investigated. C. albicans biotypes did not correlate with clinical features of oral lesions, disease stages and CD4+ lymphocyte count. Of 8 patients with recurrent oral candidiasis, 4 changed clinical features and 5 changed biotype. Our study pointed out the high frequency (28.9%) of oral lesions, especially caused by fungi and the importance of the examination of the oral cavity in children born to HIV-1 positive women.
Asunto(s)
Infecciones Oportunistas Relacionadas con el SIDA/congénito , Candidiasis Bucal/congénito , Seropositividad para VIH/complicaciones , VIH-1 , Enfermedades de la Boca/congénito , Relación CD4-CD8 , Candidiasis Bucal/etiología , Candidiasis Bucal/microbiología , Niño , Preescolar , Estudios de Cohortes , Femenino , Humanos , Lactante , Masculino , Enfermedades de la Boca/etiología , Embarazo , Complicaciones Infecciosas del EmbarazoRESUMEN
The growth of Cryptococcus neoformans in a minimal liquid synthetic medium with or without thiamine (10 micrograms/ml) was investigated. In these media the presence or absence of thiamine had no effect on the development of C. neoformans. To check these results, we performed a series of experiments on a solid form of the minimal synthetic medium. In this study a series of six serial transfers were carried out to starve the cells of nutrients that may have been carried over from their growth on rich media. In each of the transfers on the solid synthetic medium, C. neoformans showed a similar and scarce growth. This finding indicates that C. neoformans could be autotrophic in respect to thiamine.
Asunto(s)
Cryptococcus neoformans/crecimiento & desarrollo , Tiamina/fisiología , Medios de CultivoRESUMEN
A study of the vaginal yeast flora in pregnant women living in Cusco and in its region (Peru), located approximately 3000 m above sea level, is reported. We observed 300 pregnant, healthy and non-diabetic women who attended a gynaecological clinic in the Lorena, Regional or IPSS (Instituto Peruano de Seguridad Social) hospitals in Cusco. A comprehensive clinical history was obtained from each patient. It included age, work, parity, time of pregnancy, use of contraceptives or antibiotics, type of vaginal symptoms, type and amount of vaginal secretion. The yeasts were isolated from 44.3% of the cases. The positive cases were more frequently found in the following categories: 20-30 year-old patients (69.2%), ninth month of pregnancy (49.6%), first pregnancy (41.4%), no delivery (58.7%) and no abortion (66.9%). Most women complained of leukorrhea (75.9%) with mucus, scarce without odour (18.8%) or lumpy, regular, without odour (15.8%) secretion. The yeasts isolated were Candida albicans (66.2%), other Candida species (12.8%), Torulopsis glabrata (8.3%) or other Torulopsis species (2.2%), Saccharomyces cerevisiae (7.5%), Rhodotorula sp. (1.5%) and Trichosporon cutaneum (1.5%).
Asunto(s)
Micosis/epidemiología , Complicaciones Infecciosas del Embarazo/epidemiología , Enfermedades Vaginales/epidemiología , Adolescente , Adulto , Femenino , Hongos/aislamiento & purificación , Humanos , Micosis/microbiología , Perú/epidemiología , Embarazo , Complicaciones Infecciosas del Embarazo/microbiología , Enfermedades Vaginales/microbiologíaRESUMEN
The MIC values of the antifungal drug ketoconazole were evaluated on 66 Candida albicans strains. These strains were isolated from 26 HIV-1 infected patients with oral recurrent candidosis. Each episode of oral candidosis observed in these patients was orally treated with ketoconazole (200 mg/day) until the clinical disappearance of the lesions. The most frequent MIC values were 20 micrograms/ml and 10 micrograms/ml, observed in 37 and 19 isolates respectively. Only strains from five patients showed changes in their susceptibility to ketoconazole. This fact could indicate that a different strain causes the subsequent reappearance of the oral lesions, rather than the drug selecting resistant fungal strains. Our results stress the role of host characteristics in the occurrence of candidal infections, pointing to the progressing failure of the immunological response as the most important factor responsible for the recurrence of oral candidosis during HIV-1 infection.
Asunto(s)
Infecciones Oportunistas Relacionadas con el SIDA/tratamiento farmacológico , Candida albicans/efectos de los fármacos , Candidiasis Bucal/tratamiento farmacológico , Cetoconazol/uso terapéutico , Adulto , Femenino , Infecciones por VIH/microbiología , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , RecurrenciaRESUMEN
A new minimal synthetic medium, with low amount of glucose, without aminoacids, vitamins and neutral pH, which induces germ-tubes production in Candida albicans, is reported in this work. The results indicate a perfect agreement between the germ-tube test performed with the standard method in human or animal serum and this test performed in minimal synthetic medium. In this medium the germ-tube test for the presumptive identification of Candida albicans can be performed with the same formality, time and reproducibility as those in human or animal serum. This constitutes an interesting finding because it is easy to prepare, to store and is highly reproducible.
Asunto(s)
Candida albicans/fisiología , Medios de Cultivo , Candida albicans/clasificación , HumanosRESUMEN
A prospective 19-month study of 26 human immunodeficiency virus type 1-infected patients with episodes of erythematous or pseudomembranous oral candidiasis was done to evaluate the significance of Candida albicans biotypes in patients treated with antifungal therapy. Changes in the biotype of C. albicans were frequently noted in recurrent oral candidiasis. However, no correlation was found between the various biotypes and the clinical features of oral candidiasis, the clinical stage of human immunodeficiency virus type 1 infection, or the number of CD4+ lymphocytes. On the contrary, a significant correlation appeared among clinical lesion features, CD4+ cell numbers, and time of clinical disappearance of the oral lesions. Changes in the biotype of C. albicans were observed at the end of the antifungal therapy in 17 of 26 patients who had a second appearance of oral candidiasis as well as in 10 of 14 subjects who experienced a third reappearance of oral candidiasis.
Asunto(s)
Síndrome de Inmunodeficiencia Adquirida/complicaciones , Antifúngicos/uso terapéutico , Candida albicans/aislamiento & purificación , Candidiasis Bucal/microbiología , Síndrome de Inmunodeficiencia Adquirida/microbiología , Adulto , Linfocitos T CD4-Positivos/microbiología , Candidiasis Bucal/complicaciones , Candidiasis Bucal/tratamiento farmacológico , Eritema/complicaciones , Eritema/tratamiento farmacológico , Eritema/patología , Femenino , Humanos , Incidencia , MasculinoRESUMEN
A total of 90 cases of suspected dermatophytoses was observed over a period of 9 months in the city of Cusco (Peru) and in its environs. The age groups most commonly infected were 1-10 and 11-20 year old. The most common tineae diagnosed were tinea capitis (13.3%) and tinea unguium (11.1%). Only four species of dermatophytes were isolated: Microsporum canis (52.4%), Trichophyton mentagrophytes (35.7%), Tr. rubrum (9.5%) and Epidermophyton floccosum (2.4%). Dry weather, low temperature and high altitude do not seem to affect proliferation and infections by dermatophytes.
Asunto(s)
Dermatomicosis/epidemiología , Adolescente , Adulto , Factores de Edad , Anciano , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Perú/epidemiología , Prevalencia , Factores SexualesRESUMEN
Candida albicans strain B 311-10 with and without starvation was cultivated in the minimal synthetic medium of Shepherd et al., modified without biotin, amino acids, low glucose concentration and with decreasing amounts of (NH4)2SO4, to determine the optimal growth requirement for this strain. All the experiments were carried out under sterile conditions at 25 degrees C in a thermostat with initial O.D.s (675 nm) of 0.500 and 0.100. Cell growth was generally monitored everyday for six days with a spectrophotometer by determining the absorbance of the cultures at 675 nm. All the experiments were repeated three times and a statistical analysis of the data with a probability of 99% and 1% of error was performed to confirm the validity of the results. Best growth was obtained with starved cells at an initial O.D. of 0.100 and with a 0.1 g/L concentration of (NH4)2SO4. At this concentration, the growth of C. albicans B 311-10 was best between the first and the fourth day with the maximum at the third day. With (NH4)2SO4 concentrations of 0.05 and 0.5 g/L, cell growth was the same.
Asunto(s)
Sulfato de Amonio/metabolismo , Candida albicans/crecimiento & desarrollo , Candida albicans/metabolismo , Medios de CultivoRESUMEN
Eight cases of sporotrichosis originating from the metropolitan area of Cusco, Peru, and its region are described, including the circumstances of infection and the isolation of Sporothrix schenckii from the lesions. This finding classifies this particular area with high altitude, low temperature and dry weather as an endemic zone of interest in the epidemiological and ecological study of Andean sporotrichosis. Among the eight cases observed, five were of the fixed cutaneous type and three were lymphocutaneous. Six patients were male and two female. Two paediatric cases were also observed. Therapy with potassium iodide was very satisfactory, whereas poor results were obtained with ketoconazole.
Asunto(s)
Dermatomicosis/epidemiología , Cetoconazol/uso terapéutico , Yoduro de Potasio/uso terapéutico , Sporothrix/aislamiento & purificación , Esporotricosis/epidemiología , Adolescente , Adulto , Anciano , Niño , Preescolar , Dermatomicosis/tratamiento farmacológico , Femenino , Humanos , Masculino , Perú/epidemiología , Esporotricosis/tratamiento farmacológicoRESUMEN
The growth of some opportunistic yeasts (Candida albicans, Cryptococcus neoformans, Torulopsis glabrata, Rhodotorula rubra, Geotrichum candidum, Trichosporon cutaneum, Saccharomyces cerevisiae) was essayed in a solid minimal synthetic medium without vitamins. From the preliminary results some species (Candida albicans, Cryptococcus neoformans, Rhodotorula rubra, Geotrichum candidum and Saccharomyces cerevisiae) seem to be autotrophic regarding the growth factor considered indispensable for their metabolism and for this reason normally added to the common synthetic media employed.
Asunto(s)
Levaduras/crecimiento & desarrollo , Candida/crecimiento & desarrollo , Candida albicans/crecimiento & desarrollo , Cryptococcus neoformans/crecimiento & desarrollo , Medios de Cultivo , Rhodotorula/crecimiento & desarrollo , Saccharomyces cerevisiae/crecimiento & desarrollo , Trichosporon/crecimiento & desarrollo , Vitaminas/metabolismo , Levaduras/metabolismoRESUMEN
Cells of Candida albicans, after 24 hours of growth in YM, were starved, alternatively, in citrate buffer, physiological solution, MMS deprived of glucose or ammonium sulphate. The eventual growth was monitored by determining the absorbance at 675 nm. Simultaneously, the cell morphology was also controlled. In a second series of experiments, the C. albicans cells taken from YM were starved for 72 hours in one of the mediums as stated above, and then reinoculated in MMS liquid without, alternatively, glucose or ammonium sulphate. Again the eventual growth was monitored as in the above method. The achieved results indicate the presence of a reserve of nitrogen, which can be utilized when a source of C is given to the cell. We therefore discuss the apparent lack of glucidic reserve and we propose a method for the consumption of nitrogen reserve. The aim of the work is to define how to obtain cells that contain the smallest amount possible of endogenous reserve.
Asunto(s)
Candida albicans/crecimiento & desarrollo , Sulfato de Amonio/farmacología , Candida albicans/efectos de los fármacos , Candida albicans/metabolismo , Medios de Cultivo/farmacología , Metabolismo Energético , Glucosa/metabolismo , Glucosa/farmacología , Nitrógeno/metabolismoRESUMEN
Different physical and chemical methods were used to detach the chlamydoconidia of Candida albicans from its mycelium. The action of concentrated H2SO4 acid for a 4-min period on cultures lysed both the mycelium and the outer but not the inner wall layer of the chlamydoconidia. The sulfuric acid procedure is recommended as the best method to obtain mycelium free chlamydoconidia because of its simplicity, rapidity and low cost.