Assuntos
Alérgenos/química , Candida/isolamento & purificação , Cryptococcus/isolamento & purificação , Pólen/microbiologia , Rhodotorula/isolamento & purificação , Adsorção , Alnus/química , Alnus/fisiologia , Betula/química , Betula/fisiologia , Candida/classificação , Candida/genética , Corylus/química , Corylus/fisiologia , Cryptococcus/classificação , Cryptococcus/genética , Humanos , Pólen/química , Análise de Componente Principal , RNA Ribossômico/genética , Rhodotorula/classificação , Rhodotorula/genética , Federação Russa , VentoRESUMO
No abstract available.
Assuntos
Humanos , Masculino , Pessoa de Meia-Idade , Anfotericina B/uso terapêutico , Antifúngicos/farmacologia , Criptococose/diagnóstico , Cryptococcus/classificação , DNA Ribossômico/química , Fluconazol/uso terapêutico , Testes de Sensibilidade Microbiana , Diálise Peritoneal Ambulatorial Contínua , Peritonite/diagnóstico , Filogenia , Saccharomyces cerevisiae/efeitos dos fármacos , Homologia de Sequência do Ácido NucleicoRESUMO
A deep-sea yeast, Cryptococcus liquefaciens strain N6, produces two polygalacturonases, p36 and p40 (N6-PGases). These N6-PGases were highly active at 0-10 degrees C in comparison to a PGase from Aspergillus japonicus. The hydrolytic activity of these N6-PGases remained almost unchanged up to a hydrostatic pressure of 100 MPa at 24 degrees C with a very small activation volume of -1.1 ml/mol. At 10 degrees C, however, the activation volume increased to 3.3 or 5.4 ml/mol (p36 and p40, respectively), suggesting that the enzyme-substrate complexes can expand at their transition states. We speculate that such a volume expansion upon forming the enzyme-substrate complexes contributes to decreasing the activation energy for hydrolysis. This can account for the high activity of N6-PGases at low-temperature.
Assuntos
Temperatura Baixa , Cryptococcus/classificação , Cryptococcus/enzimologia , Poligalacturonase/metabolismo , Água do Mar/microbiologia , Ativação Enzimática , Hidrólise , Cinética , Oceanos e Mares , Pectinas/metabolismo , PressãoRESUMO
AIMS: The present study was conducted to screen for psychrophilic yeasts that are able to degrade pectin compounds at low temperature, and to examine the cold-active pectinolytic enzymes produced by the isolated psychrophilic yeasts. METHODS AND RESULTS: Psychrophilic yeasts, which grow on pectin as a sole carbon source, pectinolytic-psychrophilic yeast (PPY) strains PPY-3, 4, 5 and 6, were isolated from soil from Abashiri (Hokkaido, Japan). The sequences of 28S rDNA D1/D2 of strains PPY-3 and 4 indicated a taxonomic affiliation to Cryptococcus cylindricus and Mrakia frigida, respectively, strains PPY-5 and 6 belonged to Cystofilobasidium capitatum. The isolated strains were able to grow on pectin at below 5 degrees C, and showed the activities of several cold-active pectinolytic enzymes. CONCLUSION: The findings of this study indicate the possibility that the isolated strains produce novel pectinolytic enzymes that are able to degrade pectin compounds at low temperature. SIGNIFICANCE AND IMPACT OF THE STUDY: It is possible that the cold-active pectinolytic enzymes from the isolated strains can be applied to the food industry, e.g. the clarification of fruit juice below 5 degrees C.
Assuntos
Basidiomycota , Temperatura Baixa , Cryptococcus , Pectinas/metabolismo , Microbiologia do Solo , Basidiomycota/classificação , Basidiomycota/enzimologia , Basidiomycota/genética , Basidiomycota/isolamento & purificação , Hidrolases de Éster Carboxílico/metabolismo , Cryptococcus/classificação , Cryptococcus/enzimologia , Cryptococcus/genética , Cryptococcus/isolamento & purificação , DNA Ribossômico/análise , Estabilidade Enzimática , Glicosídeo Hidrolases/metabolismo , Dados de Sequência Molecular , Filogenia , Polissacarídeo-Liases/metabolismo , RNA Ribossômico 28S/genética , Análise de Sequência de DNA , Especificidade por SubstratoRESUMO
We report the first case of Cryptococcus laurentii meningitis and a rare case of Cryptococcus albidus cryptococcaemia in AIDS patients. Both infections were treated with amphotericin B and flucytosine. The C. laurentii meningitis was controlled after 2 weeks of treatment with no evidence of infection 20 months later. The patient with C. albidus cryptococcaemia, despite the amphotericin B/flucytosine combination therapy, died on the 14th day of treatment. The minimum inhibitory concentrations (MICs) for C. laurentii, as determined by Etest on RPMI 1640 agar, were 0.25 microg ml(-1) of amphotericin B, 1.25 microg ml(-1) flucytosine, 4 microg ml(-1) fluconazole, 0.50 microg ml(-1) itraconazole and 1.0 microg ml(-1) of ketoconazole. The MIC of amphotericin B for C. albidus was 0.5 microg ml(-1), flucytosine 1.25 microg ml(-1), fluzonazole 4 microg ml(-1), itraconazole 0.5 microg ml(-1) and ketonazole 0.25 microg ml(-1). The agreement of the amphotericin B MIC values obtained in antibiotic medium 3 by the broth microdilution method, with those obtained on casitone medium by Etest, was within a two-dilution range for both isolates. C. laurentii may cause meningitis and may also involve the lungs in AIDS patients.