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Category: Clinical Microbiology; Fungi and Fungal Pathogenesis
Phospholipases of Aspergillus fumigatus, Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555815523/9781555814380_Chap07-1.gif /docserver/preview/fulltext/10.1128/9781555815523/9781555814380_Chap07-2.gifAbstract:
Phospholipases are a group of esterases that are composed of two major categories, the acyl hydrolases and the phosphodiesterases. Investigations on the phospholipases of Aspergillus species have been very limited to date. Indirect evidence for extracellular phospholipase activity was demonstrated in Aspergillus fumigatus by identifying the accumulation of phospholipid breakdown products in cultures of A. fumigatus grown on lecithin using fast atom bombardment spectroscopy based on their mass ratios. On the basis of the specific degradation products found, it was predicted that A. fumigatus secretes multiple extracellular phospholipases, including phospholipase A (PLA), phospholipase B (PLB), phospholipase C (PLC), and phospholipase D (PLD). More recently, the extracellular phospholipase activity was investigated in clinical and environmental isolates of A. fumigatus. In a survey to investigate the extracellular phospholipase activity in clinical and environmental isolates of A. fumigatus, the production of extracellular phospholipase of A. fumigatus collected from different centers worldwide was compared. Pathogenicity of gene knockout strains in a pulmonary animal model are required to determine the significance of PLB activity in lung infection and disease progression. Phospholipases play an important role in the induction of cytokines in mammalian cells; for example, PLC activity from Clostridium perfringens has been reported to induce the expression of interleukin-8 (IL-8) by endothelial cells. Similarly, researchers have reported that injury of endothelial cells by phospholipases following exposure to Rickettsia conorii led to the synthesis of IL-6 and IL-8.
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General structure of a phospholipid. R1 and R2 represent fatty acyl side chains and “Head” represents the polar head group (generally choline, ethanolamine, serine, inositol, or glycerol).
Phylogentic relationship of PLAs from fungi and other organisms. Fungi abbreviations: Acap, Ajellomyces capsulatus; Acla, Aspergillus clavatus; Afla, Aspergillus flavus; Afum, Aspergillus fumigatus; Anid, Aspergillus nidulans; Aory, Aspergillus oryzae; Ater, Aspergillus terreus; Bfuc, Botryotinea fuckeliana; Cimm, Coccidiodes immitis; Cglo, Chaetomium globosum; Fgra, Fusarium graminearum; Mgri, Magnaporthe grisea; Ncra, Neurospora crassa; Nfis, Neosartorya fischeri; Nhae, Nectria haematococca; Sscl, Sclerotinia sclerotiorum. Mammalian abbreviations: Btau, Bos taurus; Hsap, Homo sapiens; Mmus, Mus musculus. Bacteria abbreviations: Save, Streptomyces avermitilis; Scoe, Streptomyces coelicolor. The neighbor-joining tree was constructed using ClustalW, and predicted protein sequences were only selected from organisms for which the whole genome was sequenced and the annotation was publicly available. *, signal peptide predicted; **, signal anchor predicted.
Phylogentic relationship of PLBs from fungi and other organisms. Fungi abbreviations: Acap, Ajellomyces capsulatus; Acla, Aspergillus clavatus; Afla, Aspergillus flavus; Afum, Aspergillus fumigatus; Anid, Aspergillus nidulans; Aory, Aspergillus oryzae; Ater, Aspergillus terreus; Calb, Candida albicans; Cimm, Coccidiodes immitis; Cglo, Chaetomium globosum; Dhan, Debaromyces hansenii; Fgra, Fusarium graminearum; Klac, Kluyveromyces lactis; Lelo, Lodderomyces elongisporus; Mgri, Magnaporthe grisea; Ncra, Neurospora crassa; Nfis, Neosartorya fischeri; Scer, Saccharomyces cerevisiae. Mammalian abbreviations: Btau, Bos taurus; Hsap, Homo sapiens; Mmus, Mus musculus. Protist abbreviations: Ddis, Dictyostelium discoideum; Glam, Giardia lamblia. The neighbor-joining tree was constructed using ClustalW, and predicted protein sequences were only selected from organisms for which the whole genome was sequenced and the annotation was publicly available. *, signal peptide predicted; **, signal anchor predicted.
Phylogentic relationship of PLCs from fungi and other organisms. Fungi abbreviations: Acap, Ajellomyces capsulatus; Acla, Aspergillus clavatus; Afla, Aspergillus flavus; Afum, Aspergillus fumigatus; Anid, Aspergillus nidulans; Aory, Aspergillus oryzae; Ater, Aspergillus terreus; Cimm, Coccidiodes immitis; Fgra, Fusarium graminearum; Nfis, Neosartorya fischeri; Rory, Rhizopus oryzae; Tres, Trichoderma reesei. Plant abbreviations: Atha, Arabidopsis thaliani; Osat, Oryza sativa. Protist abbreviation: Tthe, Tetrahymena thermophila. Bacteria abbreviations: Bper, Burkholderia mallei; Bpsu, Burkholderia psuedomallei; Btha, Burkholderia thailandensis; Ccre, Caulobacter crescentus; Mtub, Mycobacterium tuberculosis; Paer, Pseudomonas aeruginosa; Rsol, Ralstonia solanacearum; Save, Streptomyces avermitilis; Scoe, Streptomyces coelicolor; Xcam, Xanthomonas campestris; Xory, Xanthomonas oryzae. The neighbor-joining tree was constructed using ClustalW, and predicted protein sequences were only selected from organisms for which the whole genome was sequenced and annotation was publicly available. *, signal peptide predicted; **, signal anchor predicted.
Properties of predicted phospholipases from A. fumigatus