Seven compounds (1–7) were identified from the cultivation of the endophytic fungus Exophiala oligosperma (EN-21) that was isolated from the inner tissue of the marine red alga Laurencia similis. Their structures wer...Seven compounds (1–7) were identified from the cultivation of the endophytic fungus Exophiala oligosperma (EN-21) that was isolated from the inner tissue of the marine red alga Laurencia similis. Their structures were identified with spectroscopic and chemical methods as 2-phenoxynaphthalene (1), (2S, 3R, 4E, 8E)-1-O-β-D-glucopyranosyl-3-hydroxy-2-[(R)-2′-hydroxyoctadecanoyl] amino-9-methyl-4, 8-octadeca-diene (2), (22E,24R)-ergosta-7,22-dien-3β,5α,6β-triol (3), (22E, 24R)-3β, 5α, 9α-trihydroxy- ergosta-7, 22-dien-6-one (4), (22E, 24R)-5α, 6α-epoxy-ergosta-8, 22-dien-3β, 7α-diol (5), (22E, 24R)- ergosta-4, 6, 8(14), 22-tetraen-3-one (6), and euphorbol (7). This paper reports for the first time the chemical constituents of fungus Exophiala oligosperma and the discovery of compound 1 as a natural product from the fungus.展开更多
Zinc is an essential element, which is toxic for organisms in their natural environments in excessive amounts. The zinc accumulation characteristics of a Zn-tolerant strain (H93, EC50 = 1010 mg·L–1 Zn2+) and a Z...Zinc is an essential element, which is toxic for organisms in their natural environments in excessive amounts. The zinc accumulation characteristics of a Zn-tolerant strain (H93, EC50 = 1010 mg·L–1 Zn2+) and a Zn-sensitive strain (B40-3, EC50 = 26 mg·L–1 Zn2+), Exophiala spp. and their antioxidant response to Zn2+ stress were comparatively characterized. Under their respective Zn2+ median effective concentrations, H93 absorbed 2.5-fold and accumulated 5.2-fold more Zn than B40-3. An elution experiment using CaCl2 revealed that Zn mainly accumulated intracellularly in the mycelia of the two fungal strains. The modulation of antioxidant components and antioxidant enzyme activities of the two fungal strains were comparatively analyzed under different Zn2+ concentrations. The activity of the total superoxide dismutase, peroxidase, and glutathione of H93 was always higher than that of B40-3, and the malondialdehyde content in H93 was also higher than that of B40-3. The current results suggested that the Zn tolerance of Exophiala strain may be attributed to their various instinctive behaviors with different rates of Zn accumulation and modulation of antioxidant components.展开更多
Exophiala is a genus comprising several species of opportunistic black yeasts,which belongs to Ascomycotina.It is a rare cause of fungal infections.However,infections are often chronic and recalcitrant,and while the n...Exophiala is a genus comprising several species of opportunistic black yeasts,which belongs to Ascomycotina.It is a rare cause of fungal infections.However,infections are often chronic and recalcitrant,and while the number of cases is steadily increasing in both immunocompromised and immunocompetent people,detailed knowledge remains scarce regarding infection mechanisms,virulence factors,specific predisposing factors,risk factors,and host response.The most common manifestations of Exophiala infection are skin infections,and the most frequent type of deep infection is pulmonary infection due to inhalation.The invasive disease ranges from cutaneous or subcutaneous infection to systemic dissemination to internal organs.The final identification of the causative organism should be achieved through a combination of several methods,including the newly introduced diagnostic analysis,matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry,together with sequencing of the ribosomal ribonucleic acid internal transcribed spacer region of the fungi,and histological and culture findings.Regarding treatment,because anti-infective agents and natural compounds exhibited poor antibiofilm activity,few treatments have ultimately been found to be effective for specific antifungal therapy,so the optimal antifungal therapy and duration of therapy for these infections remain unknown.Therefore,most forms of disease caused by Exophiala dermatitidis require aggressive combination therapies:Both surgical intervention and aggressive antifungal therapy with novel compounds and azoles are necessary for effective treatment.展开更多
To confirm species delimitations in the‘jeanselmeiclade’in the Chaetothyriales,four independent markers were analysed,and phylogenetic trees were reconstructed using different algorithms.Reproductive isolation withi...To confirm species delimitations in the‘jeanselmeiclade’in the Chaetothyriales,four independent markers were analysed,and phylogenetic trees were reconstructed using different algorithms.Reproductive isolation within the complex and reproductive modes in the species involved were determined,in order to explore specific borderlines using Genealogical Concordance Phylogenetic Species Recognition(GCPSR).Sequences of the Internal Transcribed Spacer(ITS),partial Translation Elongation Factor 1-α(TEF1),β-Tubulin(BT2),and Actin(ACT1)genes were analysed for a set of 81 strains.Phylogenetic reconstruction was performed using neighbour-joining(NJ),maximum parsimony(MP),maximum likelihood(ML)and Bayesian analysis(BA)to evaluate the concordance of topologies obtained under different optimization criteria.Incongruence among lineages was detected by Partition Homogeneity Test(PHT).Most Exophiala species analysed in this study seemed to be preponderantly clonal.A group of species around Exophiala spinifera showed a tendency toward human pathogenicity,whereas species around E.bergeri were often associated with environments rich in hydrocarbons.Though the tree topologies were not completely identical when different algorithms were used,the four gene lineages were nearly congruent and the trees of the combined multilocus data set did not provide more phylogenetic information than those of separate data sets.ITS data are sufficient for identification of species in the‘jeanselmei-clade’.展开更多
基金Supported by the Programs from the Ministry of Science and Technology of China (Nos.2007AA09Z446,2010CB833802)the Knowledge Innovation Program of Chinese Academy of Sciences (KZCX2-YW-211-04)
文摘Seven compounds (1–7) were identified from the cultivation of the endophytic fungus Exophiala oligosperma (EN-21) that was isolated from the inner tissue of the marine red alga Laurencia similis. Their structures were identified with spectroscopic and chemical methods as 2-phenoxynaphthalene (1), (2S, 3R, 4E, 8E)-1-O-β-D-glucopyranosyl-3-hydroxy-2-[(R)-2′-hydroxyoctadecanoyl] amino-9-methyl-4, 8-octadeca-diene (2), (22E,24R)-ergosta-7,22-dien-3β,5α,6β-triol (3), (22E, 24R)-3β, 5α, 9α-trihydroxy- ergosta-7, 22-dien-6-one (4), (22E, 24R)-5α, 6α-epoxy-ergosta-8, 22-dien-3β, 7α-diol (5), (22E, 24R)- ergosta-4, 6, 8(14), 22-tetraen-3-one (6), and euphorbol (7). This paper reports for the first time the chemical constituents of fungus Exophiala oligosperma and the discovery of compound 1 as a natural product from the fungus.
文摘Zinc is an essential element, which is toxic for organisms in their natural environments in excessive amounts. The zinc accumulation characteristics of a Zn-tolerant strain (H93, EC50 = 1010 mg·L–1 Zn2+) and a Zn-sensitive strain (B40-3, EC50 = 26 mg·L–1 Zn2+), Exophiala spp. and their antioxidant response to Zn2+ stress were comparatively characterized. Under their respective Zn2+ median effective concentrations, H93 absorbed 2.5-fold and accumulated 5.2-fold more Zn than B40-3. An elution experiment using CaCl2 revealed that Zn mainly accumulated intracellularly in the mycelia of the two fungal strains. The modulation of antioxidant components and antioxidant enzyme activities of the two fungal strains were comparatively analyzed under different Zn2+ concentrations. The activity of the total superoxide dismutase, peroxidase, and glutathione of H93 was always higher than that of B40-3, and the malondialdehyde content in H93 was also higher than that of B40-3. The current results suggested that the Zn tolerance of Exophiala strain may be attributed to their various instinctive behaviors with different rates of Zn accumulation and modulation of antioxidant components.
文摘Exophiala is a genus comprising several species of opportunistic black yeasts,which belongs to Ascomycotina.It is a rare cause of fungal infections.However,infections are often chronic and recalcitrant,and while the number of cases is steadily increasing in both immunocompromised and immunocompetent people,detailed knowledge remains scarce regarding infection mechanisms,virulence factors,specific predisposing factors,risk factors,and host response.The most common manifestations of Exophiala infection are skin infections,and the most frequent type of deep infection is pulmonary infection due to inhalation.The invasive disease ranges from cutaneous or subcutaneous infection to systemic dissemination to internal organs.The final identification of the causative organism should be achieved through a combination of several methods,including the newly introduced diagnostic analysis,matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry,together with sequencing of the ribosomal ribonucleic acid internal transcribed spacer region of the fungi,and histological and culture findings.Regarding treatment,because anti-infective agents and natural compounds exhibited poor antibiofilm activity,few treatments have ultimately been found to be effective for specific antifungal therapy,so the optimal antifungal therapy and duration of therapy for these infections remain unknown.Therefore,most forms of disease caused by Exophiala dermatitidis require aggressive combination therapies:Both surgical intervention and aggressive antifungal therapy with novel compounds and azoles are necessary for effective treatment.
文摘To confirm species delimitations in the‘jeanselmeiclade’in the Chaetothyriales,four independent markers were analysed,and phylogenetic trees were reconstructed using different algorithms.Reproductive isolation within the complex and reproductive modes in the species involved were determined,in order to explore specific borderlines using Genealogical Concordance Phylogenetic Species Recognition(GCPSR).Sequences of the Internal Transcribed Spacer(ITS),partial Translation Elongation Factor 1-α(TEF1),β-Tubulin(BT2),and Actin(ACT1)genes were analysed for a set of 81 strains.Phylogenetic reconstruction was performed using neighbour-joining(NJ),maximum parsimony(MP),maximum likelihood(ML)and Bayesian analysis(BA)to evaluate the concordance of topologies obtained under different optimization criteria.Incongruence among lineages was detected by Partition Homogeneity Test(PHT).Most Exophiala species analysed in this study seemed to be preponderantly clonal.A group of species around Exophiala spinifera showed a tendency toward human pathogenicity,whereas species around E.bergeri were often associated with environments rich in hydrocarbons.Though the tree topologies were not completely identical when different algorithms were used,the four gene lineages were nearly congruent and the trees of the combined multilocus data set did not provide more phylogenetic information than those of separate data sets.ITS data are sufficient for identification of species in the‘jeanselmei-clade’.
