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W Harder - One of the best experts on this subject based on the ideXlab platform.

  • Performance of a styrene-degrading biofilter containing the yeast Exophiala jeanselmei.
    Biotechnology and bioengineering, 1997
    Co-Authors: Huub H. J. Cox, W. N. M. Van Heiningen, H. J. Doddema, R. E. Moerman, S. Van Baalen, W Harder
    Abstract:

    A general mathematical model developed for a description of pollutant degradation in a biofilm was used to evaluate the performance of a biofilter for the purification of styrene-containing gas. The biofilter contained perlite as an inert support on which a biofilm was present composed of a mixed microbial population containing the fungus Exophiala jeanselmei as a major styrene-degrading microorganism. Although styrene is a moderately hydrophobic compound, the biofilter was reaction limited at a styrene gas phase concentration of 0.1–2.4 g/m3. Limitation of biofilter performance by the mass transfer of styrene was only observed at styrene concentrations lower than 0.06 g/m3. A maximal styrene degradation rate of 62 g/(m3 · h) was maintaind for over 1 year. At a high styrene concentration, the maximal styrene degradation rate could be increased to 91 g/(m3 · h) by increasing the oxygen concentration in the gas from 20 to 40%. After 300 days of operation, the dry-weight biomass concentration of the filter bed was 41% (w/w), and an average biofilm thickness of 240–280 μm, but maximal up to 600 μm, was observed. Experimental results and model calculations indicated an effective biofilm thickness of about 80 μm. It is postulated that the thickness of the effective biofilm is determined by the oxygen availability in the biofilm. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng53: 259–266, 1997.

  • Influence of the water content and water activity on styrene degradation by Exophiala jeanselmei in biofilters
    Applied Microbiology and Biotechnology, 1996
    Co-Authors: Huub H. J. Cox, H. J. Doddema, F. J. Magielsen, W Harder
    Abstract:

    The performance at low water availability of styrene-degrading biofilters with the fungus Exophiala jeanselmei growing on perlite, the inert support, was investigated. E. jeanselmei degrades styrene at a water activity of 0.91–1. In biofilters, the styrene elimination capacity at a water activity of 0.91 is 5% of the maximal elimination capacity of 79 g m-3 h-1 (water activity 1). Application of dry air results in a rapid loss of styrene degradation activity, even at 40%–60% (w/w) water in the filter bed and at a water activity of 1. Humidification of the gas and an additional supply of water to the filter bed are necessary to maintain a high and stable styrene elimination capacity.

  • Styrene metabolism in Exophiala jeanselmei and involvement of a cytochrome P-450-dependent styrene monooxygenase.
    Applied and environmental microbiology, 1996
    Co-Authors: Huub H. J. Cox, B. W. Faber, W. N. M. Van Heiningen, H. Radhoe, H. J. Doddema, W Harder
    Abstract:

    The yeast-like fungus Exophiala jeanselmei degrades styrene via initial oxidation of the vinyl side chain to phenylacetic acid, which is subsequently hydroxylated to homogentisic acid. The initial reactions are catalyzed by a NADPH- and flavin adenine dinucleotide-dependent styrene monooxygenase, a styrene oxide isomerase, and a NAD(+)-dependent phenylacetaldehyde dehydrogenase. The reduced CO-difference spectrum of microsomal preparations of styrene-grown cells shows a characteristic absorption maximum at 450 nm, which strongly suggests the involvement of a cytochrome P-450-dependent styrene monooxygenase. Inhibition of styrene monooxygenase activity in cell extracts by cytochrome P-450 inhibitors SKF-525-A, metyrapone, and CO confirms this assumption.

  • Growth of the black yeast Exophiala jeanselmei on styrene and styrene-related compounds
    Applied Microbiology and Biotechnology, 1993
    Co-Authors: J. H. M. Houtman, Hans J. Doddema, W Harder
    Abstract:

    The black yeast Exophiala jeanselmei can grow on styrene as the sole source of carbon and energy in concentrations up to 0.36 mm. No growth is observed at higher styrene concentrations. Styrene oxidation is induced by styrene or styrene-related compounds, whereas glucose represses this styrene oxidation. E. jeanselmei shows a broad substrate specificity: various aromatic compounds are used as the sole source of carbon and energy. Styrene-grown cells can oxidize styrene, styrene oxide, phenylacetaldehyde, phenylacetic acid and 2-phenylethanol at a rate of 1.3 to 3.2 μg O2·min−1·mg−1 protein. A pathway for the degradation of styrene in E. jeanselmei is suggested.

Gary W. Procop - One of the best experts on this subject based on the ideXlab platform.

  • Relapsing Exophiala jeanselmei phaeohyphomycosis in a lung‐transplant patient
    Transplant Infectious Disease, 2001
    Co-Authors: Jimmy Chua, Steven M. Gordon, J. Banbury, Gerri S. Hall, Gary W. Procop
    Abstract:

    Dematiaceous fungi are a cause of a variety of human infections, including phaeohyphomycosis, that may affect patients with solid organ or bone marrow transplants. Exophiala jeanselmei, the most common cause of the pheomycotic cyst/subcutaneous phaeohyphomycosis in the United States, has been shown to cause disease in transplant recipients. We report a lung-transplant patient with relapsing and invasive E. jeanselmei phaeohyphomycosis, who previously had a pheomycotic cyst excised and treated with oral fluconazole. The patient was subsequently treated with re-excision and an 8-month course of oral itraconazole without relapse as to date.

  • relapsing Exophiala jeanselmei phaeohyphomycosis in a lung transplant patient
    Transplant Infectious Disease, 2001
    Co-Authors: Jimmy Chua, Steven M. Gordon, J. Banbury, Gerri S. Hall, Gary W. Procop
    Abstract:

    Dematiaceous fungi are a cause of a variety of human infections, including phaeohyphomycosis, that may affect patients with solid organ or bone marrow transplants. Exophiala jeanselmei, the most common cause of the pheomycotic cyst/subcutaneous phaeohyphomycosis in the United States, has been shown to cause disease in transplant recipients. We report a lung-transplant patient with relapsing and invasive E. jeanselmei phaeohyphomycosis, who previously had a pheomycotic cyst excised and treated with oral fluconazole. The patient was subsequently treated with re-excision and an 8-month course of oral itraconazole without relapse as to date.

Huub H. J. Cox - One of the best experts on this subject based on the ideXlab platform.

  • Performance of a styrene-degrading biofilter containing the yeast Exophiala jeanselmei.
    Biotechnology and bioengineering, 1997
    Co-Authors: Huub H. J. Cox, W. N. M. Van Heiningen, H. J. Doddema, R. E. Moerman, S. Van Baalen, W Harder
    Abstract:

    A general mathematical model developed for a description of pollutant degradation in a biofilm was used to evaluate the performance of a biofilter for the purification of styrene-containing gas. The biofilter contained perlite as an inert support on which a biofilm was present composed of a mixed microbial population containing the fungus Exophiala jeanselmei as a major styrene-degrading microorganism. Although styrene is a moderately hydrophobic compound, the biofilter was reaction limited at a styrene gas phase concentration of 0.1–2.4 g/m3. Limitation of biofilter performance by the mass transfer of styrene was only observed at styrene concentrations lower than 0.06 g/m3. A maximal styrene degradation rate of 62 g/(m3 · h) was maintaind for over 1 year. At a high styrene concentration, the maximal styrene degradation rate could be increased to 91 g/(m3 · h) by increasing the oxygen concentration in the gas from 20 to 40%. After 300 days of operation, the dry-weight biomass concentration of the filter bed was 41% (w/w), and an average biofilm thickness of 240–280 μm, but maximal up to 600 μm, was observed. Experimental results and model calculations indicated an effective biofilm thickness of about 80 μm. It is postulated that the thickness of the effective biofilm is determined by the oxygen availability in the biofilm. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng53: 259–266, 1997.

  • Influence of the water content and water activity on styrene degradation by Exophiala jeanselmei in biofilters
    Applied Microbiology and Biotechnology, 1996
    Co-Authors: Huub H. J. Cox, H. J. Doddema, F. J. Magielsen, W Harder
    Abstract:

    The performance at low water availability of styrene-degrading biofilters with the fungus Exophiala jeanselmei growing on perlite, the inert support, was investigated. E. jeanselmei degrades styrene at a water activity of 0.91–1. In biofilters, the styrene elimination capacity at a water activity of 0.91 is 5% of the maximal elimination capacity of 79 g m-3 h-1 (water activity 1). Application of dry air results in a rapid loss of styrene degradation activity, even at 40%–60% (w/w) water in the filter bed and at a water activity of 1. Humidification of the gas and an additional supply of water to the filter bed are necessary to maintain a high and stable styrene elimination capacity.

  • Styrene metabolism in Exophiala jeanselmei and involvement of a cytochrome P-450-dependent styrene monooxygenase.
    Applied and environmental microbiology, 1996
    Co-Authors: Huub H. J. Cox, B. W. Faber, W. N. M. Van Heiningen, H. Radhoe, H. J. Doddema, W Harder
    Abstract:

    The yeast-like fungus Exophiala jeanselmei degrades styrene via initial oxidation of the vinyl side chain to phenylacetic acid, which is subsequently hydroxylated to homogentisic acid. The initial reactions are catalyzed by a NADPH- and flavin adenine dinucleotide-dependent styrene monooxygenase, a styrene oxide isomerase, and a NAD(+)-dependent phenylacetaldehyde dehydrogenase. The reduced CO-difference spectrum of microsomal preparations of styrene-grown cells shows a characteristic absorption maximum at 450 nm, which strongly suggests the involvement of a cytochrome P-450-dependent styrene monooxygenase. Inhibition of styrene monooxygenase activity in cell extracts by cytochrome P-450 inhibitors SKF-525-A, metyrapone, and CO confirms this assumption.

Jimmy Chua - One of the best experts on this subject based on the ideXlab platform.

  • Relapsing Exophiala jeanselmei phaeohyphomycosis in a lung‐transplant patient
    Transplant Infectious Disease, 2001
    Co-Authors: Jimmy Chua, Steven M. Gordon, J. Banbury, Gerri S. Hall, Gary W. Procop
    Abstract:

    Dematiaceous fungi are a cause of a variety of human infections, including phaeohyphomycosis, that may affect patients with solid organ or bone marrow transplants. Exophiala jeanselmei, the most common cause of the pheomycotic cyst/subcutaneous phaeohyphomycosis in the United States, has been shown to cause disease in transplant recipients. We report a lung-transplant patient with relapsing and invasive E. jeanselmei phaeohyphomycosis, who previously had a pheomycotic cyst excised and treated with oral fluconazole. The patient was subsequently treated with re-excision and an 8-month course of oral itraconazole without relapse as to date.

  • relapsing Exophiala jeanselmei phaeohyphomycosis in a lung transplant patient
    Transplant Infectious Disease, 2001
    Co-Authors: Jimmy Chua, Steven M. Gordon, J. Banbury, Gerri S. Hall, Gary W. Procop
    Abstract:

    Dematiaceous fungi are a cause of a variety of human infections, including phaeohyphomycosis, that may affect patients with solid organ or bone marrow transplants. Exophiala jeanselmei, the most common cause of the pheomycotic cyst/subcutaneous phaeohyphomycosis in the United States, has been shown to cause disease in transplant recipients. We report a lung-transplant patient with relapsing and invasive E. jeanselmei phaeohyphomycosis, who previously had a pheomycotic cyst excised and treated with oral fluconazole. The patient was subsequently treated with re-excision and an 8-month course of oral itraconazole without relapse as to date.

Kazuko Nishimura - One of the best experts on this subject based on the ideXlab platform.

  • Intra-species variation of genotypes of Exophiala jeanselmei isolated from patients in Japan.
    Nihon Ishinkin Gakkai zasshi = Japanese journal of medical mycology, 2005
    Co-Authors: Masako Kawasaki, Hiroshi Ishizaki, Takashi Mochizuki, Kazushi Anzawa, Hiroshi Tanabe, Kazuko Nishimura
    Abstract:

    Isolates of Exophiala jeanselmei have been classified into 15 types based on their mitochondrial DNA (mtDNA). Thirteen of the 15 types and E. spinifera, which has been classified as E. jeanselmei Type 14, were confirmed to be also clearly differentiated by restriction fragment length polymorphism (RFLP) in internal transcribed spacer (ITS) regions of ribosomal RNA genes in their nuclear DNA (nDNA). Twenty strains of E. jeanselmei, newly identified or isolated from patients in Japan, were examined for mtDNA-RFLP and ITS-RFLP. The twenty isolates were comprised of: 11 E. jeanselmei Type 5, 6 E. jeanselmei Type 6, 2 Type 10, and 1 Type 8. E. jeanselmei Type 6 was the second most common strain in Japan after Type 5. Type 5 was definitely identified as E. jeanselmei var. jeanselmei and Type 8 was identified as E. jeanselmei var. lecanii-corni based on the genotypes of type strains of these species. However, two other types were still designated as E. jeanselmei Type 6 and E. jeanselmei Type 10.

  • A case of subcutaneous phaeohyphomycotic cyst due to Exophiala jeanselmei complicated with systemic lupus erythematosus.
    Mycoses, 2003
    Co-Authors: Noriko Murayama, Reiko Takimoto, Masaaki Kawai, M. Hiruma, Kenji Takamori, Kazuko Nishimura
    Abstract:

    Summary We report a case of subcutaneous phaeohyphomycosis by Exophiala jeanselmei that appeared on the extensor surface of the left lower leg of a 34-year-old woman with systemic lupus erythematosus (SLE). The superficial symptoms were a subcutaneous nodule 2.5 × 2 cm in size discharging a serous exudate from its center. Histopathological examination revealed granulomatous changes including large numbers of neutrophils in the dermis and the subcutaneous tissues. In addition, periodic acid-Schiff-positive fungal elements consisting of many yeast-like cells and chains of cells with hyphae were seen. The statistics on E. jeanselmei infections in Japan indicated that 54 cases (24 in men and 30 in women) had been reported, of which 50 (21 in men and 29 in women) were phaeohyphomycosis, and about half had underlying diseases; and the sites of the lesions were mainly on the extremities. Zusammenfassung Wir berichten uber eine subkutane Phaeohyphomykose, verursacht durch Exophiala jeanselmei auf der Streckseite des linken Unterschenkels einer 35jahrigen Patientin mit systemischem Lupus erythematodes. Eine Statistik uber Exophiala jeanselmei-infektionen in Japan fasst 54 Kasuistiken zusammen, von denen 50 Phaeohyphomykosen waren, die Halfte davon mit pradisponierender Grundkrankheit; Infektionslokalisation waren meist die Extremitaten.

  • Identification, Classification, and Phylogeny of the Pathogenic Species Exophiala jeanselmei and Related Species by Mitochondrial Cytochrome b Gene Analysis
    Journal of clinical microbiology, 2001
    Co-Authors: Li Wang, Makoto Miyaji, Koji Yokoyama, Kazuko Nishimura
    Abstract:

    We analyzed a 402-bp sequence of the mitochondrial cytochrome b gene of 34 strains of Exophiala jeanselmei and 16 strains representing 12 related species. The strains of E. jeanselmei were classified into 20 DNA types and 17 amino acid types. The differences between these strains were found in 1 to 60 nucleotides and 1 to 17 amino acids. On the basis of the identities and similarities of nucleotide and amino acid sequences, some strains were reidentified: i.e., two strains of E. jeanselmei var. hetermorpha and one strain of E. castellanii as E. dermatitidis (including the type strain), three strains of E. jeanselmei as E. jeanselmei var. lecanii-corni (including the type strain), three strains of E. jeanselmei as E. bergeri (including the type strain), seven strains of E. jeanselmei as E. pisciphila (including the type strain), seven strains of E. jeanselmei as E. jeanselmei var. jeanselmei (including the type strain), one strain of E. jeanselmei as Fonsecaea pedrosoi (including the type strain), and one strain of E. jeanselmei as E. spinifera (including the type strain). Some E. jeanselmei strains showed distinct nucleotide and amino acid sequences. The amino-acid-based UPGMA (unweighted pair group method with the arithmetic mean) tree exhibited nearly the same topology as those of the DNA-based trees obtained by neighbor joining, maximum parsimony, and maximum likelihood methods.

  • Mitochondrial DNA analysis of Exophiala jeanselmei var. lecanii-corni and Exophiala castellanii
    Mycopathologia, 1999
    Co-Authors: Masako Kawasaki, Kazuko Nishimura, Hiroshi Ishizaki, Tadahiko Matsumoto, Tetsuo Matsuda, Makoto Miyaji
    Abstract:

    A Japanese clinical isolate (KU-A-0094) which was identified by de Hoog et al. as Exophiala jeanselmei var. lecanii-corni with difficulty, was compared with 5 strains including the type cultures of E. jeanselmei var. lecanii-corni , var. jeanselmei and E. castellanii using RFLP (restriction fragment length polymorphism) patterns of mtDNA (mitochondrial DNA). RFLP patterns of KUA-0094 were identical with those of E. jeanselmei var. lecanii-corni and different from those of E. castellanii with restriction enzymes of Hae III, Msp I and hin dIII. Therefore, de Hoog et al.'s identification of KU-A-0094 was confirmed. Additionally, mtDNA-RFLP patterns of E. jeanselmei var. lecanii-corni and E. jeanselmei var. jeanselmei were also different from each other. Consequently E. jeanselmei var. lecanii-corni seem to be a species in its own right rather than a variant of E. jeanselmei .