Surface Characteristics of Aspergillus Conidia

Hess, W. M.; Stocks, Dayna L.

doi:10.1080/00275514.1969.12018769

Cited by 51 publications

(11 citation statements)

References 4 publications

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“…These are clearly visible in situ on spore sheaths of Streptomyces griseus, S. venezuelae and S. coelicolor (Wildermuth et al 1971) and fragments from them rodlets ') are easily detached. Similar surface patterns have been observed on spores of Aspergillus and Penicillium species (Hess, Sassen & Remsen, 1968;Hess & Stocks, 1969) and on spore coats of some Bacillus species . In other species (e.g.…”

Section: Discussionsupporting

confidence: 56%

Fine Structure of the Spore Sheath of Some Streptomyces Species

Williams

Bradshaw

Costerton

et al. 1972

Journal of General Microbiology

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S U M M A R YThe fine structure of the spore sheaths of some Streptomyces species was studied by carbon replication of intact and freeze-etched specimens and by negative staining. Young vegetative hyphae lacked a sheath but developed one before the onset of sporing. Substructures were observed on all sheath material; these differed between species and in sporogenous hyphae at different stages of development. Four components were recognized : hollow or grooved elements; amorphous material ; fine fibrillar elements; and subunits of spines and hairs. The interrelationships of the components and the possible roles of the sheath were discussed. I N T R O D U C T I O NStreptomyces spore chains are enclosed during their development by a thin sheath. Spores of some species appear to be ornamented when examined by electron microscopy. The ornaments, which may be warts, spines, hairs (Kiister, 1955) (Wildermuth, 1972 a, b).When spores are detached from their chains, the sheath may remain partially covering them or they may become free from it (Williams & Sharples, 1970). Properties of spores, such as their hydrophobicity, are often assigned to the 'spore surface' and the contribution of the sheath is obscure. More information about the structure and composition of the sheath is therefore required. The results from a survey of sheath structure in several species are reported here. METHODS Cultures.The following strains were used : Streptomyces finZayi (hairy sheath), S. gZaucescens (hairy), S. griseus (smooth), S. thermoflavus (knobbly), S. venezuelae (smooth), S. viridochromogenes (spiny) and Streptomyces sp. (FI) (smooth). They were grown on oatmeal agar (Waksman, 1961) at 25 "C for 2 to 3 weeks, with the exception of S. thermofavus which was grown at 45 "C for 3 days. In studies of germinating spores, spore imprints were made on sterile coverslips which were then incubated in moist sterile sand for 24 to 48 h.

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Section: Discussionsupporting

confidence: 56%

Fine Structure of the Spore Sheath of Some Streptomyces Species

Williams

Bradshaw

Costerton

et al. 1972

Journal of General Microbiology

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“…Subsequently, it was shown that products of one such gene (SC3) possessed the remarkable property of spontaneously polymerising at gas-water interfaces into SDS-insoluble amphipathic sheets with the highly hydrophobic surface facing the gas and the hydrophilic surface facing the water Wösten, 2001). Under transmission electron microscopy (TEM) these sheets comprised regular arrays of microfibrils, closely resembling the rodlet layers recognised on the cell surface of many dry-spored mould fungi (Hess et al, 1968;Hess et al, 1969;Dempsey and Beever, 1979) (Fig. 2).…”

Section: Discovery Of Hydrophobinsmentioning

confidence: 99%

Structural analysis of hydrophobins

Sunde

Kwan

Templeton

et al. 2008

Micron

203

123

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“…Previous electron microscopy studies have shown "rodlet" structures on the Aspergillus nidulans spore wall (18). These are composed primarily of protein (4,10,31) and are thought to serve several different functions (31).…”

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Assessment of Elasticity and Topography of Aspergillus nidulans Spores via Atomic Force Microscopy

Zhao

Schaefer

Marten

2005

Appl Environ Microbiol

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Previous studies have described both surface morphology and adhesive properties of fungal spores, but little information is currently available on their mechanical properties. In this study, atomic force microscopy (AFM) was used to investigate both surface topography and micromechanical properties of Aspergillus nidulans spores. To assess the influence of proteins covering the spore surface, wild-type spores were compared with spores from isogenic rodA ؉ and rodA ؊ strains. Tapping-mode AFM images of wild-type and rodA ؉ spores in air showed characteristic "rodlet" protein structures covering a granular spore surface. In comparison, rodA ؊ spores were rodlet free but showed a granular surface structure similar to that of the wild-type and rodA ؉ spores. Rodlets were removed from rodA ؉ spores by sonication, uncovering the underlying granular layer. Both rodlet-covered and rodlet-free spores were subjected to nanoindentation measurements, conducted in air, which showed the stiffnesses to be 110 ؎ 10, 120 ؎ 10, and 300 ؎ 20 N/m and the elastic moduli to be 6.6 ؎ 0.4, 7.0 ؎ 0.7, and 22 ؎ 2 GPa for wild-type, rodA ؉ and rodA ؊ spores, respectively. These results imply the rodlet layer is significantly softer than the underlying portion of the cell wall.Fungal spores are of importance medically (25), agriculturally (9), and industrially (3) and provide fungi a natural means of reproduction, dispersion, and survival in adverse environmental conditions (22,29). These benefits are in large part due to the spore cell wall, which has been compared to a man-made composite material (24). The wall is typically composed of various polysaccharide and protein components (17) and imparts great strength and resistance to chemical attack (24).Knowledge of spore cell wall mechanical properties is necessary for a complete understanding of molecular component ultrastructure. Spore mechanical properties are also relevant during wall expansion which occurs as part of the germination process. It has been pointed out that changes in cell wall mechanical properties are central to the emergence of the germ tube (6, 21). While a number of studies have described surface morphology (4, 13, 14, 31) and adhesive properties (7, 27) of fungal spores, no information is currently available on their relevant micromechanical properties (e.g., elasticity).The elasticity of an object can be described in terms of stress and strain. Stress is defined as the force applied per unit area, while strain is the resulting amount of deformation per unit length. The ratio of stress to strain (for an elastic material following Hooke's law) is defined as the elastic modulus (E), and describes the mechanical resistance of a material during elongation or compression. A large E implies a stiff or strong material, while a small E implies a softer material. To measure E, as well as other micromechanical properties, of different types of biological materials, a number of authors have used atomic force microscopy (AFM) (1, 2, 32, 33). To carry out these types of tests, a...

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Surface Characteristics of Aspergillus Conidia

Cited by 51 publications

References 4 publications

Fine Structure of the Spore Sheath of Some Streptomyces Species

Fine Structure of the Spore Sheath of Some Streptomyces Species

Structural analysis of hydrophobins

Assessment of Elasticity and Topography of Aspergillus nidulans Spores via Atomic Force Microscopy

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