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Polyphasic taxonomy of Aspergillus section Usti

¹ CBS Fungal Biodiversity Centre, PO Box 85167, NL-3508 AD Utrecht, the Netherlands
² BioCentrum-DTU, Søltofts Plads, Building 221, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
³ Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6701 Szeged, P.O. Box 533, Hungary

^* Correspondence: J. Houbraken, j.houbraken{at}cbs.knaw.nl

	Abstract

TOP Abstract INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION References

 
Aspergillus ustus is a very common species in foods, soil and indoor environments. Based on chemical, molecular and morphological data, A. insuetus is separated from A. ustus and revived. A. insuetus differs from A. ustus in producing drimans and ophiobolin G and H and not producing ustic acid and austocystins. The molecular, physiological and morphological data also indicated that another species, A. keveii sp. nov. is closely related but distinct from A. insuetus. Aspergillus section Usti sensu stricto includes 8 species: A. ustus, A. puniceus, A. granulosus, A. pseudodeflectus, A. calidoustus, A. insuetus and A. keveii together with Emericella heterothallica.

Taxonomic novelties: Aspergillus insuetus revived, Aspergillus keveii sp. nov.

Keywords actin / Aspergillus / β-tubulin / calmodulin / extrolite profiles / ITS / phylogenetics / polyphasic taxonomy.

	INTRODUCTION

TOP Abstract INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION References

 
Aspergillus ustus is a very common filamentous fungus found in foods, soil and indoor air environments (Samson et al. 2002). This species is considered as a rare human pathogen that can cause invasive infection in immunocompromised hosts. However, A. ustus has been noted increasingly as causes of invasive aspergillosis in tertiary care centres in the US (Malani & Kaufman 2007). Up to date, 22 invasive aspergillosis cases have been reported to be caused by A. ustus (Verweij et al. 1999; Pavie et al. 2005; Panackal et al. 2006; Yildiran et al. 2006). Several studies indicate that A. ustus isolates are resistant to amphotericin B, echinocandins and azole derivatives (Verweij et al. 1999; Pavie et al. 2005; Gene et al. 2001; Garcia-Martos et al. 2005). Other species related to A. ustus can also cause human or animal infections. Aspergillus granulosus was found to cause disseminated infection in a cardiac transplant patient (Fakih et al. 1995), while A. deflectus has been reported to cause disseminated mycosis in dogs (Robinson et al. 2000; Kahler et al. 1990; Jang et al. 1986).

A. ustus is a variable species. Raper & Fennell (1965) stated that "not a single strain can be cited as wholly representative of the species as described". Indeed, A. ustus isolates may vary in their colony colour from mud brown to slate grey, with colony reverse colours from uncoloured through yellow to dark brown (Raper & Fennell 1965; Kozakiewicz 1989). Molecular data also indicate that this species is highly variable; RAPD analysis carried out in various laboratories could be used to detect clustering of the isolates (Rath et al. 2002; Panackal et al. 2006), and sequence analysis of parts of the ribosomal RNA gene cluster also detected variability within this species (Henry et al. 2000; Peterson 2000; Hinrikson et al. 2005).

We examined a large set of A. ustus isolates and related species originating from environmental and clinical sources to clarify the taxonomic status of the species, and to clarify the taxonomy of Aspergillus section Usti. The methods used include sequence analysis of the ITS region (intergenic spacer region and the 5.8 S rRNA gene of the rRNA gene cluster), and parts of the β-tubulin, calmodulin and actin genes, analysis of extrolite profiles, and macro- and micromorphological analysis of the isolates.

	MATERIALS AND METHODS

TOP Abstract INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION References

 
Morphological examination. The strains examined are listed in Table 1. Both clinical and environmental strains were grown as 3-point inoculations on Czapek yeast agar (CYA), malt extract agar (MEA), creatine agar (CREA) and yeast extract sucrose agar (YES) at 25 °C, and on CYA at 37 °C for 7 d (medium compositions according to Samson et al. 2004). For micro morphological examination light microscopy (Olympus BH2 and Zeiss Axioskop 2 Plus) was employed.

Extrolite analysis. Extrolites were analysed by HPLC using alkylphenone retention indices and diode array UV-VIS detection as described by Frisvad & Thrane (1987), with minor modifications as described by Smedsgaard (1997). Standards of ochratoxin A and B, aflavinine, asperazine, austamide, austdiol, kotanin and other extrolites from the collection at Biocentrum-DTU were used to compare with the extrolites from the species under study.

Isolation and analysis of nucleic acids. The cultures used for the molecular studies were grown on malt peptone (MP) broth using 10 % (v/v) of malt extract (Brix 10) and 0.1 % (w/v) bacto peptone (Difco), 2 mL of medium in 15 mL tubes. The cultures were incubated at 25 °C for 7 d. DNA was extracted from the cells using the Masterpure^TM yeast DNA purification kit (Epicentre Biotechnol.) according to the instructions of the manufacturer. Fragments containing the ITS region were amplified using primers ITS1 and ITS4 as described previously (White et al. 1990). Amplification of part of the β-tubulin gene was performed using the primers Bt2a and Bt2b (Glass 1995). Amplifications of the partial calmodulin and actin genes were set up as described previously (Hong et al. 2005). Sequence analysis was performed with the Big Dye Terminator Cycle Sequencing Ready Reaction Kit for both strands, and the sequences were aligned with the MT Navigator software (Applied Biosystems). All the sequencing reactions were purified by gel filtration through Sephadex G-50 (Amersham Pharmacia Biotech, Piscataway, NJ) equilibrated in double-distilled water and analyzed on the ABI PRISM 310 Genetic Analyzer (Applied Biosystems).

Data analysis. The sequence data was optimised using the software package Seqman from DNAStar Inc. Sequence alignments were performed by using CLUSTAL-X (Thompson et al. 1997) and improved manually. The neighbour-joining (NJ) method was used for the phylogenetic analysis. For NJ analysis, the data were first analysed using the Tamura-Nei parameter distance calculation model with gamma-distributed substitution rates (Tamura & Nei 1993), which were then used to construct the NJ tree with MEGA v. 3.1 (Kumar et al. 2004). To determine the support for each clade, a bootstrap analysis was performed with 1000 replications.

For parsimony analysis, the PAUP v. 4.0 software was used (Swofford 2000). Alignment gaps were treated as a fifth character state and all characters were unordered and of equal weight. Maximum parsimony analysis was performed for all data sets using the heuristic search option with 100 random taxa additions and tree bisection and reconstruction (TBR) as the branch-swapping algorithm. Branches of zero length were collapsed and all multiple, equally parsimonious trees were saved. The robustness of the trees obtained was evaluated by 1000 bootstrap replications (Hillis & Bull 1993). An Aspergillus versicolor isolate was used as outgroup in these experiments. Unique sequences of the ITS, actin, calmodulin and β-tubulin gene sequences have been deposited in the GenBank under accession numbers EU076344 [GenBank] -EU76377.

	RESULTS

TOP Abstract INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION References

 
Phylogenetic analyses
For the molecular analysis, four genomic regions, the ITS region, and parts of the actin, calmodulin and β-tubulin genes were amplified and sequenced. Phylogenetic analysis of the data was carried out using the neighbour-joining technique and parsimony analysis. The trees obtained by the different approaches were identical, neighbour-joining trees based on the different data sets are shown in Figs 1, 2, 3 and 4. During analysis of part of the β-tubulin gene, 487 characters were analyzed, 111 of which were found to be parsimony informative. The topology of the tree is the same as that of one of the more than 10⁴ maximum parsimony trees constructed by the PAUP program (length: 216 steps, consistency index: 0.8148, retention index: 0.9679). The calmodulin data set included 474 characters, with 172 parsimony informative characters (1 MP tree, tree length: 360, consistency index: 0.8083, retention index: 0.9550). The actin data set included 406 characters, with 161 parsimony informative characters (3 MP trees, tree length: 292, consistency index: 0.8870, retention index: 0.9633). The ITS data set included 482 characters, 26 of which were parsimony informative (>10⁴ MP trees, tree length: 71, consistency index: 0.9155, retention index: 0.9781).

View larger version (9K): [in this window] [in a new window]   Fig. 1. Neighbour-joining tree based on β-tubulin sequence data of Aspergillus section Usti. Numbers above branches are bootstrap values. Only values above 70 % are indicated.

View larger version (10K): [in this window] [in a new window]   Fig. 2. Neighbour-joining tree based on calmodulin sequence data of Aspergillus section Usti. Numbers above branches are bootstrap values. Only values above 70 % are indicated.

View larger version (9K): [in this window] [in a new window]   Fig. 3. Neighbour-joining tree based on actin sequence data of Aspergillus section Usti. Numbers above branches are bootstrap values. Only values above 70 % are indicated.

View larger version (10K): [in this window] [in a new window]   Fig. 4. Neighbour-joining tree based on ITS sequence data of Aspergillus section Usti. Numbers above branches are bootstrap values. Only values above 70 % are indicated.

Morphological and physiological studies
Phenotypic comparison of the different members of the section Usti showed that eight taxa could be distinguished. Various characters showed to be valuable for differentiation (see also Table 2). One of the main criteria is the growth rate on CYA at 37 °C. A. calidoustus, A. pseudodeflectus and A. granulosus had high growth rates at this temperature, while E. heterothallica only grew restrictedly. The other members of this section were unable to grow at 37 °C, which reduces the potential of these species to become opportunistic human pathogens. The growth rate and the mycelium colour on creatin agar (CREA) also proved to be a good tool to differentiate between the species examined. Some species, like A. ustus, A. puniceus, A. insuetus and A. keveii have a good growth on this medium. Since sporulation on this medium is often inhibited, this medium was also useful to determine the colour of the mycelium. The colours varied from bright yellow by A. puniceus and E. heterothallica to faint yellow in A. ustus to colourless in the other species. Another useful character was the use of the Ehrlich test to detect the presence of indol metabolites. This feature gave, with the exception of A. keveii, very clear-cut results. Besides these features, the colony diam on YES was also suitable to differentiate between A. insuetus and the other species.

Extrolite profiles
Aspergillus ustus has been claimed to produce a range of extrolites including austdiol (Vleggaar et al. 1974), Austin (Chexal et al. 1976), austocystins (Steyn & Vleggaar 1974; Kfir et al. 1986), brevianamide A (Steyn 1973), sterigmatocystin (Rabie et al. 1977), austalides (de Jesus et al. 1987), austamide (Steyn 1971), dehydroaustin (Scott et al. 1986), pergillin (Cutler et al. 1980), dehydropergillin (Cutler et al. 1981), phenylahistin (Kanoh et al. 1997), ophiobolins G & H (Cutler et al. 1984), drimans (Hayes et al. 1996), diacetoxyscirpenol (Tuomi et al. 2000) and ustic acid (Raistrick & Strickings 1951).

The mycotoxins and other extrolites found to be produced by the examined species in this study are listed in Table 3. Species assigned to section Usti could clearly be divided in three chemical groups based on the extrolites produced by them. A. ustus, A. granulosus and A. puniceus produced ustic acids in common. A. ustus and A. puniceus also produced austocystins and versicolorins. In the second chemical group, A. pseudodeflectus produced drimans (Hayes et al. 1996) in common with the other species in this group, and also several unique unknown compounds. A. calidoustus isolates produced drimans and ophiobolins in common with A. insuetus and A. keveii, but also produced austins not identified in other species of section Usti. A. insuetus isolates also produced pergillin, while A. keveii together with some other isolates produced nidulol. In the third chemical group, E. heterothallica has been reported to produce emethallicins A-F (Kawahara et al. 1989, 1990a, 1990b), 5"-hydroxyaveranthin (Yabe et al. 1991), emeheterone (Kawahara et al. 1988), emesterones A & B (Hosoe et al. 1998), 5"-hydroxyaveranthin (Yabe et al. 1991), Mer-NF8054X (Mizuno et al. 1995). This latter compound is an 18,22-cyclosterol derivative, and was also identified in an A. ustus isolate (Mizuno et al. 1995). Apart from this chemical similarity Emericella heterothallica appear to be quite different from the anamorphic species in section Usti, in agreement with actin sequencing data. Austamide, deoxybrevianamide E and austdiol could not be detected in any of the strains examined here and the strain producing these mycotoxins should be reexamined.

Comparing the extrolites profiles of section Usti with other sections within subgenus Nidulantes, nidulol and versicolorins are also produced by members of sections Versicolores and Nidulantes (Cole & Schweikert 2003). Interestingly, versicolorins and 5"-hydroxyaveranthin are intermediates of the aflatoxin biosynthetic pathway and also produced by species assigned to Aspergillus section Flavi and Ochraceorosei (Yabe et al. 1991; Frisvad et al. 2005). However, while the versicolorins are precursors of sterigmatocystin in section Ochraceorosei, Versicolores and Nidulantes, they are precursors of austocystins in section Usti.

Section Usti contains the only Aspergillus species known to produce pergillins, ophiobolins, austins, austocystins, ustic acids, drimans, Mer-NF8054X, austalides, deoxybrevianamides and austamide and thus this section is chemically unique. We have not examined the species for production of emethallicins, emesterones and emeheterones, as standards of these compounds were not available.

	DISCUSSION

TOP Abstract INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION References

 
Raper and Fennell (1965) classified A. ustus in the Aspergillus ustus group together with four other species: A. panamensis, A. puniceus, A. conjunctus and A. deflectus. Later, Kozakiewicz (1989) revised the taxonomy of the group, and included A. ustus, A. pseudodeflectus, A. conjunctus, A. puniceus, A. panamensis and A. granulosus into the A. ustus species group, and established the A. deflectus group including A. deflectus, A pulvinus and A. silvaticus based on morphological studies. Klich (1993) treated A. granulosus as member of section Versicolores, and found that A. pseudodeflectus is only weakly related to this section based on morphological treatment of section Versicolores. Peterson (2000) transferred most species of section Usti to section Nidulantes based on sequence analysis of part of the 28 S rRNA gene. On his cladogram, A. ustus, A. pseudodeflectus, A. granulosus and A. puniceus form a well-supported branch closely related to A. versicolor and its allies, while A. deflectus is on another branch related to A. elongatus and A. lucknowensis. Peterson (2000) transferred A. conjunctus, A. funiculosus, A. silvaticus, A. panamensis and A. anthodesmis to section Sparsi. Recently Varga et al. (submitted) studied large numbers of isolates from clinical and other sources using molecular, morphological and physiological approaches. Phylogenetic analysis of partial β-tubulin, calmodulin, actin and ITS sequences indicated that none of the clinical isolates recognised previously as A. ustus belong to the A. ustus species. All but two of these isolates formed a well-defined clade related to A. pseudodeflectus based on sequence analysis of protein coding regions. Morphological and physiological examination of the isolates indicated that they are able to grow above 37 °C, in contrast with A. ustus isolates, and give a positive Ehrlich reaction, in contrast with related species including A. granulosus, A. ustus, and A. pseudodeflectus. These isolates were described as A. calidoustus.

Aspergillus ustus (Bainier) Thom & Church was redescribed by Thom & Church (1926) based on Sterigmatocystis usta Bainier. In this manual, A. insuetus (Bainier) Thom & Church was also accepted based on S. insueta Bainier (Thom & Chuch, 1926), but later A. insuetus was abandoned (Thom and Raper, 1945) and included in the broad description of A. ustus in Raper and Fennell (1965). Our studies clarified that A. insuetus is a valid species which can be distinguished from A. ustus and other species assigned to Aspergillus section Usti. A. insuetus could be separated from the other members of the section Usti by various phenotypic characters. The most important one is the slower growth rate on YES agar and clear differences in extrolite profiles (Table 2). This finding was supported by all the different data sets used to characterise section Usti. The molecular data showed that this species is more related to A. calidoustus and A. pseudodeflectus than A. ustus. Also different extrolite patterns were observed. There were many differences between A. ustus and A. insuetus, and, like the molecular data, this species was mostly related to A. calidoustus and A. pseudodeflectus. The main difference between the latter species was the production of a pergillin-like compound by A. insuetus (Table 3).

Our polyphasic taxonomic approach revealed that Aspergillus section Usti includes eight species: A. ustus, A. puniceus, A. granulosus, A. pseudodeflectus, A. calidoustus, A. insuetus and A. keveii sp. nov. The phylogenetic trees based on ITS, calmodulin and β-tubulin sequence data indicated that E. heterothallica also belongs to this section. This species has similar morphology of the conidiophores and Hülle cells. In our study we were not able to observe ascospores by crossing the two mating strains but these are described by Raper and Fennell (1965: 502-503).

Aspergillus calidoustus Varga et al. Eukaryotic Cell submitted. Fig. 5.

View larger version (150K): [in this window] [in a new window]   Fig. 5. Aspergillus calidoustus. A-B. Colonies at 25 °C after 7 d. A. CYA. B. MEA. C-E, G-H Conidiophores. F. Hülle cells. I. Conidia. Scale bars = 10 µm, except F = 30 µm

Other no. of the type: strain 677

Description strain
Colony diam, 7 d, in mm: CYA25 27-32; CYA37 20-35; MEA25 35-48; YES 36-41

Colony colour on CYA: blond/greyish yellow, brownish grey or greyish brown

Conidiation on CYA: abundant

Reverse colour (CYA): yellow with beige or olive brown centre

Colony texture: floccose

Conidial heads: loosely columnar

Stipe: 150-300 x 4-7 µm, smooth, brown

Vesicle diam/shape: 9-15 µm, pyriform to broadly spathulate

Conidium size/shape/surface texture: 2.7-3.5 x µm, globose, very rough ornamentation (0.5-0.8 µm high), inner and outer wall visible

Hülle cells: sparsely produced, irregularly elongated, in scattered groups

Ehrlich reaction: violet

Growth on creatine: weak to moderate growth with hyaline mycelium, no acid production

Diagnostic features: good growth at 37 °C, violet Ehrlich reaction, coarsely roughened to echinulate conidia

Cultures examined: CBS 121589, 121601-121616

Similar species: A. pseudodeflectus

Distribution: U.S.A., Turkey, Finland, Germany, Netherlands

Ecology and habitats: indoor air, rubber, construction material, human

Extrolites: Drimans, ophiobolins G and H, austins

Pathogenicity: pathogenic to humans (Verweij et al. 1999; Weiss & Thiemke 1983; Pavie et al. 2005; Panackal et al. 2006; Yildiran et al. 2006; Iwen et al. 1998)

Aspergillus granulosus Raper & Thom, Mycologia 36: 565. 1944. Fig. 6.

View larger version (146K): [in this window] [in a new window]   Fig. 6. Aspergillus granulosus. A-B. Colonies at 25 °C after 7 d. A. CYA. B. MEA. C-H Conidiophores. I. Conidia. Scale bars = 10 µm, except C = 30 µm.

Other no. of the type: ATCC 16837, NRRL 1932, WB 1932, CBS 452.93

Description
Colony diam, 7 d, in mm: CYA25 30-48; CYA37 30-51; MEA25 25-37; YES25 35-45; CZA25 17-25

Colony colour: buff to dull brown

Conidiation: moderate

Reverse colour (CYA): dull yellow to red brown

Colony texture: floccose, plane or irregularly furrowed

Conidial head: hemispherical to radiate

Stipe: 100-600 x 5.5-8 µm, thin-walled, smooth, straight, tan to light brown

Vesicle diam/shape: 15-25 x 12-18 µm, ovoid to elliptical

Conidium size/shape/surface texture: (3.3-)4-4.5(-5.5) µm, globose, delicately echinulate

Hülle cells: irregularly globose, ovoid to elongate, 12-30 µm, in colourless clusters at colony margins

Ehrlich reaction: violet

Growth on creatine: poor growth with inconspicuous mycelium, no acid production

Cultures examined: CBS 119.58, CBS 588.65, IBT 23478

Diagnostic features: small colourless clusters of irregularly globose Hülle cells, giving the colony a characteristic granular appearance, good growth at 37 °C and violet Ehrlich reaction

Similar species: -

Distribution: U.S.A.

Ecology and habitats: soil

Extrolites: Ustic acids, a compound resembling sterigmatocystin, nidulol, drimans

Pathogenicity: pathogenic to humans (Fakih et al. 1995)

Aspergillus insuetus (Bainier) Thom & Church, Manual of the aspergilli: 153. 1929. Fig. 7.

View larger version (149K): [in this window] [in a new window]   Fig. 7. Aspergillus insuetus. A-B. Colonies at 25 °C after 7 d. A. CYA. B. MEA. C-H Conidiophores. I. Conidia. Scale bars = 10 µm, except C = 30 µm.

• = Sterigmatocystis insueta Bainier (1908)
  

Type: CBS 107.25, from South Africa, Sartory

Other no. of the type: ATCC 1033; IFO 4128; NRRL 279; NRRL 1726; Thom No. 4658.245

Description
Colony diam, 7 d, in mm: CYA 28-32; CYA37 no growth; MEA25 36-41; YES 23-30

Colony colour: almost black in center, shading through gray to white sterile floccose marginal areas

Conidiation on CYA: moderate to good

Reverse colour (CYA): yellow olive to blackish brown with age

Colony texture: floccose

Conidial head: radiate to hemispherical

Stipe: 300 x 4-8 µm, smooth, brown

Vesicle diam/shape: 11-16 µm, hemispherical to subglobose

Conidium size/shape/surface texture: 3.2-4 µm, globose, distinct roughened and inner and outer wall visible, fuligeneous, the colour mostly aggregated into echinulations of the cell-wall, and even forming bars and tubercules at times

Hülle cells: variously coiled or curved, in scattered groups

Ehrlich reaction: violet

Growth on creatine: good growth with hyaline mycelium, no acid production

Cultures examined: CBS 107.25, CBS 119.27, CBS 102278

Similar species: A. keveii

Distribution: South Africa, Spain

Diagnostic features: no growth at 37 °C, violet Ehrlich reaction, restricted growth on YES, coarsely roughened to echinulate conidia

Ecology and habitats: soil (?), human

Extrolites: Drimans, ophiobolins G and H, pergillin-like

Pathogenicity: caused subcutaneous infection (Gené et al. 2001)

Aspergillus keveii sp. nov. Varga, Frisvad & Samson - MycoBank MB505570. Fig. 8.

View larger version (152K): [in this window] [in a new window]   Fig. 8. Aspergillus kerveii. A-B. Colonies at 25 °C after 7 d. A. CYA. B. MEA. C-H Conidiophores. I. Conidia. Scale bars = 10 µm.

Coloniae in 7 dieibus et 25 °C in agaro MEA 36-41 mm, in CYA 30-39 mm, in YES 40-46 mm, in CREA 25-32 mm diam; auctus in 7 dieibus et 37 °C in agaro CYA nullus. Sporulatio in CYA abundans; colonia brunneogrisea vel subroseobrunnea; textura coloniae floccosa; colonia reversa flavide olivaceobrunnea vel atrobrunnea. Capitula conidialia laxe columnaria; stipites 150-300 x 4-6 µm, pariete laevi, brunneo; vesciculae pyriformes, 9-13 µm in lat., biseriatae; metulae 4.7-6.7 x 2.8-3.6 µm; phialides 5.7-7 x 2-3 µm; conidia globosa, 2.4-2.8 µm diam., ornamento exasperato vel echinulato. Cellulae "hülle" irregulariter elongatae, (10-) 25-40(-65) µm in long., in cumulis dispersis.

Colonies on MEA 36-41 mm, on CYA 30-39 mm, on YES 40-46 mm, on CREA 25-32 mm in diam. after 7 d at 25 °C, no growth on CYA after 7 d at 37 °C. Conidial heads abundant on CYA, colony colour brownish grey to pinkish brown, colony texture floccose, reverse yellow olive brown to dark brown. Conidial heads loosely columnar; stipes 150-300 x 4-6 µm, smooth walled, brown in colour; vesicles 9-13 µm wide, pyriform, biseriate; metulae covering the upper half to three-fourths of the vesicle, measuring 4.7-6.7 x 2.8-3.6 µm µm; phialides 5.7-7 x 2-3 µm; conidia globose 2.4-2.8 µm, coarsely roughened to echinulate. Hülle cells (10-)25-40(-65) µm, irregularly elongated, produced in scattered groups.

Etymology: named after Prof. Ferenc Kevei, eminent mycologist devoting his life to Aspergillus research.

Type: CBS 209.92

Ehrlich reaction: violet, with exception of CBS 113227

Growth on creatine: good growth with hyaline mycelium, no or weak acid production

Diagnostic features: no growth at 37 °C, good growth on CREA and YES, coarsely roughened to echinulate conidia; Hülle cells in scattered groups, violet Ehrlich reaction

Cultures examined: CBS 561.65, CBS 209.92 and CBS 113227

Similar species: A. insuetus

Distribution: U.S.A., Turkey, Finland, Germany, Netherlands

Ecology and habitats: indoor air, rubber, construction material, human

Extrolites: Drimans, ophiobolins G and H, nidulol

Pathogenicity: not reported

Notes: CBS 113227 is deviating in having larger conidial heads and small (2.6 µm), finely roughened pinkish brown coloured conidia

Aspergillus pseudodeflectus Samson & Mouchacca, Antonie van Leeuwenhoek 41(3): 325. 1975. Fig. 9.

View larger version (144K): [in this window] [in a new window]   Fig. 9. Aspergillus pseudodeflectus. A-C. Colonies at 25 °C after 7 d. A. MEA + 40 % sucrose. B. CYA + 20 % sucrose. C. MEA. D-I. Conidiophores. H. Conidia. Scale bars = 10 µm.

Other no. of the type: IMI 278381

Description
Colony diam, 7 d, in mm: CYA25 43-49; CYA37 15-20; MEA25 35-45; YES 20-30; CZA25 25-26

Colony colour: white mycelial felt intermixed with brown conidiogenous structures

Conidiation: sparse

Reverse colour (CZA): yellow

Colony texture: velvety appearance, no sporulation

Conidial head: radiate, brown

Stipe: 35-200 x 2.5-3.5 µm, rough-walled with warty protuberances, brown

Vesicle diam/shape: 4-12 µm, globose to clavate

Conidium size/shape/surface texture: 3.5-5 µm, globose to ellipsoidal, brown, ornamented with small warts and colour bars

Hülle cells: absent

Ehrlich reaction: none

Growth on creatine: weak to moderate growth with hyaline mycelium, no acid production

Diagnostic features: Growth at 37 °C, curved brown conidiophores and the ornamented conidia, absence of Hülle cells

Cultures examined: CBS 756.74, CBS 596.65

Similar species: A. calidoustus

Distribution: Egypt, U.S.A.

Ecology and habitats: soil

Extrolites: Drimans (Hayes et al. 1996), unknown compounds

Pathogenicity: not reported

Aspergillus puniceus Kwon and Fennell, The genus Aspergillus: 547. 1965. Fig. 10.

View larger version (149K): [in this window] [in a new window]   Fig. 10. Aspergillus puniceus. A-B. Colonies at 25 °C after 7 d. A. CYA. B. MEA. C-H Conidiophores. I. Sclerotia. J. Conidia. Scale bars = 10 µm, except D = 30 µm.

• = A. ustus var. laevis Blochwitz (1945)
  

Type: CBS 495.65, from soil, Zarcero, Costa Rica

Other no. of the type: ATCC 16800; IMI 126692; WB 5077

Description
Colony diam, 7 d, in mm: CYA 40-50; CYA37 no growth; MEA25 40-45; YES 48-53; CZA25: 40-50 mm

Colony colour: pinkish orange near vinaceous pink, with wine red exudate droplets

Conidiation: moderate

Reverse colour (CYA): dark yellow brown or crème brown

Colony texture: floccose

Conidial head: radiate to short columnar, dull green becoming light drab with age

Stipe: 150-250(-300) x 5.5-6(-8) µm, aerially borne stipes up to 135 x 3-4 µm, straight, smooth

Vesicle diam/shape: 8-16 µm (subglobose), 15-18 x 13-15 µm (elliptical)

Conidium size/shape/surface texture: 2.5-3.3 µm, globose, roughened

Hülle cells: elongate, crescent shaped or irregularly twisted, often aggregated into yellowish masses

Ehrlich reaction: no reaction

Growth on creatine: moderate to good growth with bright yellow mycelium, no acid production (in some isolates weak acid production under colony)

Cultures examined: CBS 495.65, CBS 122.33, CBS 128.62, 9377, V41-02, NRRL 29173

Diagnostic features: No growth at 37 °C, good growth on creatine with brightly pigmented yellow mycelium, Hülle cells aggregated into yellowish masses

Similar species: A. ustus

Distribution: Costa Rica, U.S.A., Canada, Netherlands

Ecology and habitats: soil, indoor air, human

Extrolites: ustic acids, austocystins, nidulol, versicolorins, phenylahistin, sterigmatocystin-related compound (in CBS 128.62)

Pathogenicity: isolated from mouth wash and faeces

Aspergillus ustus (Bainier) Thom & Church, The aspergilli: 152. 1924. Fig. 11.

View larger version (146K): [in this window] [in a new window]   Fig 11. Aspergillus ustus. A-B. Colonies at 25 °C after 7 d. A. CYA. B. MEA. C-E. G-H Conidiophores. F. Hülle cells. I. Conidia. Scale bars = 10 µm, except F = 30µm.

• = Sterigmatocystis usta Bainier (1881)
  
• = Aspergillus humus Abbott (1926)
  

Type: CBS 261.67, culture contaminant, U.S.A.

Other no. of the type: ATCC 1041; ATCC 16818; IMI 211805; NRRL 275; QM 7477; WB 275; Thom 3556

Description
Colony diam, 7 d, in mm: CYA 36-43; CYA37 no growth; MEA25 39-46; YES 42-50

Colony colour: greyish brown to dark brown

Conidiation on CYA: moderate

Reverse colour (CZA): yellow-olive edge with olive brown centre

Colony texture: floccose, plane, sulcate or umbonate

Conidial head: radiate to hemispherical

Stipe: 400 x 3-6 µm, aerially borne stipes up to 125 x 2-5 µm, smooth, brownish

Vesicle diam/shape: 7-15 µm, hemispherical to subglobose

Conidium size/shape/surface texture: 3.2-4.5 µm, globose, roughened, greenish to dark yellow brown

Hülle cells: irregularly ovoid or elongate, usually scattered

Ehrlich reaction: no reaction

Growth on creatine: good growth with faint yellow mycelium, no acid production

Cultures examined: CBS 116057, CBS 114901, CBS 261.67, CBS 133.55, CBS 239.90, CBS 113233, CBS 113232, NRRL 285, NRRL 280, NRRL 1609, NRRL 29172

Diagnostic features: No growth at 37 °C; good growth on creatine with faint yellow pigmented mycelium; Hülle cells typically scattered or form irregular masses and not associated with pigmented mycelium

Similar species: A. puniceus

Distribution: U.S.A., Poland, Netherlands, Canada

Ecology and habitats: soil, indoor air, bat dung

Extrolites: Ustic acids, austocystins, versicolorins, austalides, a compound related to sterigmatocystin, nidulol

Pathogenicity: isolated from biopsy of man with brain tumour (CBS 239.90). However, this isolate does not grow at 37 °C on normal agar media and might therefore be a culture contamination.

Emericella heterothallica (Kwon-Chung, Fennell & Raper) Malloch & Cain [anamorph: A. compatibilis Samson & Gams], Can. J. Bot. 50: 62. 1972. Fig. 12.

View larger version (144K): [in this window] [in a new window]   Fig. 12. Emericella heterothallica. A-C. Colonies at 25 °C after 7 d. A. CYA. B. MEA. C. Crossing of mating strains. D-E, F-H. Conidiophores. I. Conidia. Scale bars = 10 µm.

Other no. of the type: ATCC 16824; IHEM 2064; IMI 139278; RV 34434; WB 5097; IBT 22604

Description
Colony diam, 7 d, in mm: CYA25 35-39; CYA37 5-8; MEA25 40-42; YES25 38-42

Colony colour: cream to yellow to orange

Conidiation: limited

Reverse colour (CYA): yellow to orange to pink becoming dark reddish brown

Colony texture: floccose

Conidial head: hemispherical to short columnar

Stipe: 185-410 x 5-11 µm, generally sinuous, brownish with age, smooth

Vesicle diam/shape: 13-20 µm

Conidium size/shape/surface texture: 2.5-4 µm, globose, echinulate, yellow green

Hülle cells: 600-700(-1000) µm, pyriform to oval to elongate to twisted, in globose to subglobose masses

Cleistothecia: produced in a heterothallic manner, 270-510 µm, cinnamon to dark purple, surrounded by Hülle cells

Ascospores: 4-4.5 x 3.5-4 µm, lenticular, orange brown in colour, with two pleated equatorial crests (1.5-2 µm), with convex smooth

Ehrlich reaction: none

Growth on creatine: weak growth with yellow coloured mycelium, no acid production

Diagnostic features: heterothallic species, weak growth at 37 °C

Cultures examined: CBS 489.65, CBS 488.65 = IBT 22607

Similar species: -

Distribution: Costa Rica

Ecology and habitats: soil

Extrolites: Found in this study: Sterigmatocystin, versicolorins, Mer-NF8054X. Literature data: emethallicins A-F (Kawahara et al. 1989, 1990a), 5"-hydroxyaveranthin (Yabe et al. 1991), emeheterone (Kawahara et al. 1988), emesterones A & B (Hosoe et al. 1998), 5"-hydroxyaveranthin (Yabe et al. 1991), Mer-NF8054X (Mizuno et al. 1995).

Pathogenicity: not reported

	Acknowledgments

 
We would like to thank the Danish Technical Research Council for support to Center for Microbial Biotechnology and Ellen Kirstine Lyhne for technical support. Dr Emory Simmons kindly provided a Latin diagnosis for the new species.

	References

TOP Abstract INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION References

 

Chexal KK, Spinger JP, Clardy J, Cole RJ, Kirksey JW, Dorner JW, Cutler HG, Strawter BJ (1976). Austin, a novel polyisoprenoid mycotoxin from Aspergillus ustus. Journal of the American Chemical Society 98:6748 .[CrossRef][Medline]

Cole RJ, Cox RH (1981). Handbook of toxic fungal metabolites. New York: Academic Press.

Cole RJ, Schweikert MA (2003). Handbook of secondary fungal metabolites. Vols. 1-3. Amsterdam: Elsevier Academic Press.

Cutler HG, Crumley FG, Springer JP, Cox RH (1981). Dihydropergillin: a fungal metabolite with moderate plant growth inhibiting properties from Aspergillus ustus. Journal of Agricultural and Food Chemistry 29:981 -983.[CrossRef]

Cutler HG, Crumley FG, Springer JP, Cox RH, Cole RJ, Dorner JW, Thean JE (1980). Pergillin: a nontoxic fungal metabolite with moderate plant growth inhibiting properties from Aspergillus ustus. Journal of Agricultural and Food Chemistry 28:989 -991.[CrossRef]

Cutler HG, Crumley FG, Cox RH, Springer JP, Arrendale RF, Cole RJ, Cole PD (1984). Ophiobolins G and H: new fungal metabolites from a novel source, Aspergillus ustus. Journal of Agricultural and Food Chemistry 32:778 -782.[CrossRef]

Fakih MG, Barden GE, Oakes CA, Berenson CS (1995). First reported case of Aspergillus granulosus infection in a cardiac transplant patient. Journal of Clinical Microbiology 33:471 -473.[Abstract]

Frisvad JC, Skoube P, Samson RA (2005). Taxonomic comparison of three different groups of aflatoxin producers and a new efficient producer of aflatoxin B1, sterigmatocystin and 3-O-methylsterigmatocystin, Aspergillus rambellii sp. nov. Systematic and Applied Microbiology 28:442 -453.[CrossRef][Medline]

Frisvad JC, Thrane U (1987). Standardized high performance liquid chromatography of 182 mycotoxins and other fungal metabolites based on alkylphenone retention indices and UV-VIS spectra (diode array detection). Journal of Chromatography 404:195 -214.[CrossRef][Medline]

Frisvad JC, Thrane U (1993). Liquid chromatography of mycotoxins. Journal of Chromatography Library 54:253 -372.

Gams W, Christensen M, Onions AH, Pitt JI, Samson RA (1985). Infrageneric taxa of Aspergillus. In: Advances in Penicillium and Aspergillus Systematics. (Samson RA, Pitt JI, eds). New York: Plenum Press:55 -62.

Garcia-Martos P, Garcia-Agudo L, Gutierrez-Calzada J, Ruiz-Aragon J, Saldarreaga A, Marin P (2005). In vitro activity of amphotericin B, itraconazole and voriconazole against 20 species of Aspergillus using the Sensititre microdilution method. Enfermedades Infecciosas y Microbiología Clínica 23:15 -18 [in Spanish][CrossRef][Medline]

Gene J, Azon-Masoliver A, Guarro J, De Febrer G, Martinez A, Grau C, Ortoneda M, Ballester F (2001). Cutaneous infection caused by Aspergillus ustus, an emerging opportunistic fungus in immunosuppressed patients. Journal of Clinical Microbiology 39:1134 -1136.[Abstract/Free Full Text]

Glass NL, Donaldson GC (1995). Development of primer sets designed for use with the PCR to amplify conserved genes from filamentous ascomycetes. Applied and Environmental Microbiology 61:1323 -1330.[Abstract]

Hayes MA, Wrigley SK, Chetland I, Reynolds EE, Ainsworth AM, Renno DV, Latif MA, Cheng XM, Hupe DJ, Charlton P, Doherty AM (1996). Novel drimane sesquiterpene esters from Aspergillus ustus var. pseudodeflectus with endothelin receptor binding activity. Journal of Antibiotics 49:505 -512.[Medline]

Henry T, Iwen PC, Hinrichs SH (2000). Identification of Aspergillus species using internal transcribed spacer regions 1 and 2. Journal of Clinical Microbiology 38:1510 -1515.[Abstract/Free Full Text]

Hillis DM, Bull JJ (1993). An empirical test of bootstrapping as a method for assessing confidence in phylogenetic analysis. Systematic Biology 42:182 -192.[CrossRef][ISI]

Hinrikson HP, Hurst SF, Lott TJ, Warnock DW, Morrison CJ (2005). Assessment of ribosomal large-subunit D1-D2, internal transcribed spacer 1, and internal transcribed spacer 2 regions as targets for molecular identification of medically important Aspergillus species. Journal of Clinical Microbiology 43:2092 -2103.[Abstract/Free Full Text]

Hong SB, Go SJ, Shin HD, Frisvad JC, Samson RA (2005). Polyphasic taxonomy of Aspergillus fumigatus and related species. Mycologia 97:1316 -1329.[Abstract/Free Full Text]

Hosoe T, Sameshima T, Dobashi K, Kawai KI (1998). Structures of two new 18,22-cyclosterols, emesterones A and B, from Emericella heterothallica. Chemical and Pharmaceutical Bulletin 46:850 -852.

Iwen PC, Rupp ME, Bishop MR, Rinaldi MG, Sutton DA, Tarantolo S, Hinrichs SH (1998). Disseminated aspergillosis caused by Aspergillus ustus in a patient following allogeneic peripheral stem cell transplantation. Journal of Clinical Microbiology 36:3713 -3717.[Abstract/Free Full Text]

Jang SS, Dorr TE, Biberstein EL, Wong A (1986). Aspergillus deflectus infection in four dogs. Journal of Medical and Veterinary Mycology 24:95 -104.[CrossRef]

Jesus AE de, Horak RM, Steyn PS, Vleggaar R (1987). Metabolites of Aspergillus ustus. Part 4. Stable-isotope labelling studies on the biosynthesis of the austalides. Journal of the Chemical Society Perkin Transactions 1 1987:2253 -2257.

Kahler JS, Leach MW, Jang S, Wong A (1990). Disseminated aspergillosis attributable to Aspergillus deflectus in a springer spaniel. Journal of the American Veterinary Medical Association 197:871 -874.[Medline]

Kanoh K, Kohno S, Asari T, Harada T, Katada J, Muramatsu M, Kawashima H, Sekiya H, Uno I (1997). (-)-Phenylahistin: A new mammalian cell cycle inhibitor produced by Aspergillus ustus. Bioorganical and Medicinal Chemistry Letters 7:2847 -2852.[CrossRef]

Kawahara N, Nakajima S, Yamazaki M, Kawai K (1989). Structure of a novel epidithiodioxopiperazine, emethallicin A, a potent inhibitor of histamine release from Emericella heterothallica. Chemical and Pharmaceutical Bulletin 37:2592 -2595.

Kawahara N, Nozawa K, Nakajima S, Kawai K (1988). Emeheterone, a pyrazinone derivative from Emericella heterothallica. Phytochemistry 27:3022 -3024.[CrossRef]

Kawahara N, Nozawa K, Yamazaki M, Nakajima S, Kawai K (1990b). Structures of novel epipolythiodioxopiperazines, emethallicins B, C, and D, potent inhibitors of histamine release, from Emericella heterothallica. Chemical and Pharmaceutical Bulletin 38:73 -78.

Kawahara N, Nozawa K, Yamazaki M, Nakajima S, Kawai KI (1990a). Novel epidithiodioxopiperazines, emethallicins E and F, from Emericella heterothallica. Heterocycles 30:507 -515.

Kfir R, Johannsen E, Vleggaar R (1986). Mutagenic activity of austocystins - secondary metabolites of Aspergillus ustus. Bulletin of Environmental Contaminants and Toxicology 37:643 -650.[CrossRef]

Klich MA (1993). Morphological studies of Aspergillus section Versicolores and related species. Mycologia 85:100 -107.[CrossRef]

Kozakakiewicz Z (1989). Aspergillus species in stored products. Mycological Papers 161: 1-188.

Kumar S, Tamura K, Nei M (2004). MEGA3: Integrated Software for Molecular Evolutionary Genetics Analysis and Sequence Alignment. Briefings in Bioinformatics 5: 150-163.[Abstract/Free Full Text]

Malani AN, Kauffman CA (2007). Changing epidemiology of rare mould infections: implications for therapy. Drugs 67:1803 -1812.[CrossRef][Medline]

Mizuno R, Kawahara N, Nozawa K, Yamazaki M, Nakajima S, Kawai K (1995). Stereochemistry of an 18,22-Cyclosterol, Mer-NF8054X, from Emericella heterothallica and Aspergillus ustus. Chemical and Pharmaceutical Bulletin 43: 9-11.

Nakai K, Kanda Y, Mineishi S, Hori A, Chizuka A, Niiya H, Tanimoto T, Ohnishi M, Kami M, Makimoto A, Tanosaki R, Matsuno Y, Yamazaki N, Tobinai K, Takaue Y (2002). Primary cutaneous aspergillosis caused by Aspergillus ustus following reduced-intensity stem cell transplantation. Annals of Hematology 81:593 -596.[CrossRef][Medline]

Panackal AA, Imhof A, Hanley EW, Marr KA (2006). Aspergillus ustus infections among transplant recipients. Emerging Infectious Diseases 12:403 -408.[ISI][Medline]

Pavie J, Lacroix C, Hermoso DG, Robin M, Ferry C, Bergeron A, Feuilhade M, Dromer F, Gluckman E, Molina JM, Ribaud P (2005). Breakthrough disseminated Aspergillus ustus infection in allogeneic hematopoietic stem cell transplant recipients receiving voriconazole or caspofungin prophylaxis. Journal of Clinical Microbiology 43:4902 -4904.[Abstract/Free Full Text]

Peterson SW (2000). Phylogenetic relationships in Aspergillus based on rDNA sequence analysis. In: Integration of modern taxonomic methods for Penicillium and Aspergillus classification. Samson RA, Pitt JI, eds. Amsterdam: Harwood Academic Publishers: 323-355.

Rabie CJ, Steyn M, van Schalkwyk GC (1977). New species of Aspergillus producing sterigmatocystin. Applied and Environmental Microbiology 33:1023 -1025.[Abstract/Free Full Text]

Raistrick H, Stickings CE (1951). Studies in the biochemistry of micro-organisms; ustic acid, a metabolic product of Aspergillus ustus (Bainier) Thom & Church. Biochemical Journal 48:53 -66.[Medline]

Raper KB, Fennell DI (1965). The genus Aspergillus. Baltimore: Williams & Wilkins.

Rath PM, Petermeier K, Verweij PE, Ansorg R (2002). Differentiation of Aspergillus ustus strains by random amplification of polymorphic DNA. Journal of Clinical Microbiology 40:2231 -2233.[Abstract/Free Full Text]

Robinson WF, Connole MD, King TJ, Pitt JI, Moss SM (2000). Systemic mycosis due to Aspergillus deflectus in a dog. Australian Veterinary Journal 78:600 -602.[Medline]

Samson RA, Hoekstra ES, Frisvad JC (eds) (2004). Introduction to food and airborne fungi. 7th ed. Utrecht: Centraal Bureau voor Schimmelcultures.

Samson RA, Mouchacca J (1975). Additional notes on species of Aspergillus, Eurotium and Emericella from Egyptian desert soil. Antonie van Leeuwenhoek 41:343 -451.[CrossRef][Medline]

Scott FE, Simpson TJ, Trimble LA, Vederas JC (1986). Biosynthesis of meroterpenoid austin by Aspergillus ustus: synthesis and incorporation of 13C, 18O-labelled ethyl 3,5 dimethylorsellinate. Journal of the Chemical Society. Chemical Communications 1986:214 -215.

Singh SB, Smith JL, Sabnis GS, Dombrowski AW, Schaeffer JM, Goetz MA, Bills GF (1991). Structure and conformation of ophiobolin K y 6-epiophiobolin K from Aspergillus ustus as a nematocidal agent. Tetrahedron 47:6931 -6938.[CrossRef]

Smedsgaard J (1997). Micro-scale extraction procedure for standardized screening of fungla metabolite production in cultures. Journal of Chromatography A 760:264 -270.[CrossRef][Medline]

Steyn PS (1971). Austamide, a new toxic metabolite from Aspergillus ustus. Tetrahedron Letters 1971:3331 -3334.

Steyn PS (1973). The structures of five diketopiperazines from Aspergillus ustus. Tetrahedron 29:107 -120.[CrossRef]

Steyn PS, Vleggaar R (1974). Austocystins. Six novel dihydrofuro (3",2":4,5) furo(3,2-b)xanthenones from Aspergillus ustus. Journal of the Chemical Society Perkin Transactions 1 1974:2250 -2256.

Stiller MJ, Teperman L, Rosenthal SA, Riordan A, Potter J, Shupack JL, Gordon MA (1994). Primary cutaneous infection by Aspergillus ustus in a 62-year-old liver transplant recipient. Journal of the American Academy of Dermatology 31:344 -347.[Medline]

Swofford T (2000). PAUP: Phylogenetic analysis using parsimony. v. 4.0. Sunderland: Sinauer Associates.

Tamura K, Nei M (1993). Estimation of the number of nucleotide substitutions in the control region of mitochondrial DNA in humans and chimpanzees. Molecular Biology and Evolution 10:512 -526.[Abstract]

Thom C, Church MB (1926). The aspergilli. Baltimore: Williams and Wilkins.

Thom C, Raper KB (1945). Manual of the aspergilli. Baltimore: Williams and Wilkins.

Tuomi T, Reijula K, Johnsson T, Hemminki K, Hintikka EL, Lindroos O, Kalso S, Koukila-Kahkola P, Mussalo-Rauhamaa H, Haahtela T (2000). Mycotoxins in crude building materials from water-damaged buildings. Applied and Environmental Microbiology 66:1899 -1904.[Abstract/Free Full Text]

Vasilenko OV, Bezmelnitsyn NV, Keselman SA, Shulutko EM, Pivnik AV (2002). Fungemia caused by Aspergillus ustus in a patient with acute myeloblastic leukemia: case report Unpublished: See Entrez "AJ316611" at NCBI: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=nucleotide&list_uids=15706255&dopt=GenBank

Verweij PE, van den Bergh MF, Rath PM, de Pauw BE, Voss A, Meis JF (1999). Invasive aspergillosis caused by Aspergillus ustus: case report and review. Journal of Clinical Microbiology 37:1606 -1609.[Abstract/Free Full Text]

Vleggaar R, Steyn PS, Nagel DW (1974). Constitution and absolute configuration of austdiol, the main toxic metabolite from Aspergillus ustus. Journal of the Chemical Society Perkin Transactions 1 1974:45 -49.

Weiss LM, Thiemke WA (1983). Disseminated Aspergillus ustus infection following cardiac surgery. American Journal of Clinical Pathology 80:408 -411.[Medline]

White TJ, Bruns T, Lee S, Taylor J (1990). Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. In: PCR Protocols: A guide to methods and applications. (Innis MA, Gelfand DH, Sninsky JJ, White TJ, eds). New York: Academic Press: 315-322.

Yabe K, Nakamura Y, Nakajima H, Ando Y, Hamasaki T (1991). Enzymatic conv. of norsolorinic acid to averufin in aflatoxin biosynthesis. Applied and Environmental Microbiology 57:1340 -1345.[Abstract/Free Full Text]

Yildiran ST, Mutlu FM, Saracli MA, Uysal Y, Gonlum A, Sobaci G, Sutton DA (2006). Fungal endophthalmitis caused by Aspergillus ustus in a patient following cataract surgery. Medical Mycology 44:665 -669.[CrossRef][Medline]

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