Aspergillus sydowii is a fungus that causes several diseases in humans. It has been implicated in the death of sea fan corals ( Gorgonia spp.) in the Caribbean Sea.
Taxonomy
The species was first described in 1913 as
Sterigmatocystis sydowii by
Georges Bainier and Auguste Theodore Sartory.
and Margaret Brooks Church transferred it to
Aspergillus in 1926.
Description
When grown in
pure culture on agar plates,
A. sydowii produces blue-green colonies with reddish-brown shades. The
heads are effuse (spread out), while the stalks of the
are
hyaline (translucent), smooth, and measure up to 500
micrometre. Swollen cells (vesicles) are spherical or nearly so, and the conidiogenous cells (cells that produce conidia) are biseriate—having
that arise from metulae (sterile cells below the phialides). The conidia are echinulate (spiky), roughly spherical, and measure 2.5–4.0 μm in diameter.
Habitat and distribution
Aspergillus sydowii is a
Saprophyte fungus found in soil that can contaminate food and is occasionally pathogenic to humans. It is the predominant fungus found on wheat
Qu, the most widely used source of raw microorganisms and crude enzymes for Chinese
rice wine brewing.
Since the 1990s it has been found to be present in sea water in the Caribbean region and has been shown to be the cause of
aspergillosis in sea fans.
[ It is not known to reproduce in the marine environment and several hypotheses exist as to its source. The infective agent may have always existed in the ocean but not previously caused the disease or it may have accumulated after run-off of soil from land. The hypothesis that it entered the ocean via dust blown across the Atlantic from Africa seems unlikely to be correct as none of the samples of dust collected from African locations contained A. sydowii though they did contain other species of Aspergillus. A more likely vector seems to be the flamingo tongue snail ( Cyphoma gibbosum), a specialist Predation on sea fans, and the fungus has been found in its faeces.]
Pathogenicity
Aspergillus sydowii has been implicated in the pathogenesis of several human diseases, including aspergillosis, onychomycosis, and keratomycosis.
Infection of sea fans
The sea fan Gorgonia ventalina can be infected by Aspergillus sydowii. An epizootic epidemic occurred in the 1990s in the Caribbean resulting in the death or injury of many gorgonians. Large individuals were more affected than small ones and reproduction was reduced in infected specimens. The immune response of the sea fan included increased production of melanin and other secondary metabolites including chitinase and peroxidase, and the aggregation of at the infection site.[
]
Bioactive compounds
Several indole alkaloids have recently (2012) been isolated from laboratory-grown pure culture of the fungus. The compounds 4-(2-methoxyphenyl)-1-piperazinyl(1-methyl-1H-indol-3-yl)-methanone, cyclotryprostatin B, fumiquinazoline D, fumitremorgin B, fumiquinazoline C, fumiquinazoline B, fumiquinazoline A, fumiquinazoline F, fumiquinazoline G are all previously known to science, having been found in other Aspergillus species. Cyclotryprostatin E is a novel compound, known only from this species.
The strain A. sydowii F5, originally isolated from Chinese wheat, contains an alpha-galactosidase enzyme; this enzyme, which hydrolysis the terminal alpha-galactosyl moieties from and , is used in enzyme replacement therapy to functionally compensate for genetic alpha-galactosidase A deficiency.
