Electron microscopy of swelling and germinating conidiospores of<i>Aspergillus niger</i>

Tsukahara, Tohru

doi:10.1080/00362176885190371

Cited by 19 publications

(10 citation statements)

References 15 publications

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“…Within 12 to 16 h following inoculation into the synthetic medium, the conidia became swollen with partial to complete 10ss of the echinate outer hull. These observations were similar to those for the hydrated conidia of other species of Aspergillus (Tsukahara, 1968;Florance, Denison & Allen, 1972). The hydrated conidium shown in fig.…”

Section: Figures 1 and 2 Illustrate Cross Sections Of Permanganate-fisupporting

confidence: 83%

Ultrastructural studies of induced morphogenesis byAspergillus parasiticus

Garrison¹,

Boyd²

1974

Med Mycol

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Vegetative development of Aspergillus parasiticus may follow two patterns of morphogenesis depending upon the presence or absence of manganese ions in the medium. This alteration of morphology is suggestive of a hyphal-yeastlike dimorphism. Aspects of this morphogenesis of A. parasiticus are illustrated and described. Anomalies of the fine structural appearance of the cell wall of hydrated conidia following inoculation into a manganese-deficient synthetic medium occurred prior to germ tube formation. After approximately 96 h incubation, ceils of A. parasiticus underwent alteration to thick-walled, slightly elongate forms resembling arthrospores. These altered forms had scanty cytoplasm and 3 distinct cell wall layers. The thick inner layer had multiple, slightly undulating parallel boundaries perhaps resulting from the repeated deposition of newly synthesized cell wall material. Along these boundaries, small areas of electron-dense material were associated with delicate membrane-like microstructures suggestive of bilayer leaflets. Ultrastructurally, these altered forms of A. parasiticus do not resemble closely those reported previously for the yeastlike phases of certain of those fungi exhibiting true hyphal-yeastlike dimorphism.Aspergillusparasiticus Speare is of interest because of its ability to produce aflatoxin B1, a potent hepatocarcinogen (Wogan, 1969). In a study of the biosynthesis of aflatoxin B1, Detroy & Ceigler (1971) observed that vegetative development of A. parasiticus may follow 2 patterns of morphogenesis depending upon the presence or absence of manganese ions in the culture medium. When conidia ofA. parasiticus were inoculated into complex media containing yeast extract, the fungus grew in its normal hyphal form. When cultured in a manganese-deficient synthetic medium, it grew as large spherical, "yeastlike" structures which appeared to be a stable, morphogenetic form. Upon subsequent transfer of the "yeastlike" forms to synthetic medium containing manganese, further growth produced filamentous hyphal cells. These 2 patterns of morphogenesis suggested a hyphal-yeastlike dimorphism as characterized by certain of the important fungal pathogens of man and animals.It is the purpose of this study to describe the fine structure of the 2 vegetative forms of A. parasiticus, and to examine certain aspects of ultrastructural reorganization occurring during the culturally induced morphogenesis as characterized by this fungal organism. MATERIALS AND METHODSStock cultures of A. parasiticus ATCC 15517 were maintained on potato dextrose agar (Difco) slants at 30°C. Conidia were harvested from 5-day old slant cultures by flooding them with sterile deionized water and gently dislodging the conidia with an inoculating loop. The conidial suspensions were washed several times by centrifugation with sterile deionized water. Five ml samples of a heavy suspension of washed conidia were inoculated into 50 ml vol of the synthetic medium described by Detroy & Ciegler 179 Med Mycol Downloaded from informahealthcare.com...

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Section: Figures 1 and 2 Illustrate Cross Sections Of Permanganate-fisupporting

confidence: 83%

Ultrastructural studies of induced morphogenesis byAspergillus parasiticus

Garrison¹,

Boyd²

1974

Med Mycol

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“…In A. niger melanin is mainly present in the cell wall of conidia but is not formed in germinating spores and young hyphae (Tsukahara, 1968). To confirm this notion in our experimental system we compared expression of the alb1 gene in sporulating cultures with its activity in mycelia developing in submerged shaking culture by RT-PCR analysis.…”

Section: Alb1 Is Expressed In Sporulating But Not In Dormant or Germimentioning

confidence: 67%

“…Consistently, expression of the alb1/pksP gene, which encodes a polyketide synthase essential for melanin biosynthesis in Aspergillus fumigatus, is in vitro mostly confined to spore forming cultures (Tsai et al, 1998;Langfelder et al, 2001). During germination, Aspergillus spores typically shed an outer cell wall layer carrying most of the melanin (Tsukahara, 1968;Tronchin et al, 1995).…”

Section: Introductionmentioning

confidence: 90%

“…While we observed opposite aggregation behavior of ungerminated spores of alb1 and AB1:13 at pH 2.0 and 3.5, further pellet development was indistinguishable between mutant and wild type under the culture conditions used in our experiments. Melanin is mainly present in an outer layer of ungerminated spores, which is shed during germination (Tsukahara, 1968). Thus, the lack of melanin should mostly affect the interaction of ungerminated spores but to a much lesser extend those of germ tubes and/or hyphae.…”

Section: Aggregation Of Ungerminated Spores Does Not Contribute Signimentioning

confidence: 99%

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The role of initial spore adhesion in pellet and biofilm formation in Aspergillus niger

Priegnitz

Wargenau

Brandt

et al. 2012

Fungal Genetics and Biology

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“…Several investigators (16,17,35) have observed similar patterns of conidial germination. Bartnicki-Garcia (2) considered this was the most common mode of germination in fungi.…”

Section: Discussionmentioning

confidence: 73%

Electron microscopic studies of saprobic and parasitic forms ofCoccidioides immitis

Sun¹,

Sekhon

Huppert

1979

Med Mycol

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During studies of both saprobic and parasitic cycles of Coccidioides immitis, we found that the hyphae contained septa with simple pores, Woronin bodies, pinocytotie vesicles and/or lomasomes. The alternating thallic arthroconidia were released by fracturing of the adjacent sterile cells. The endospores were formed by progressive cleavage of the spherules. The taxonomic classification of C. immitis still remains obscure.

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Electron microscopy of swelling and germinating conidiospores ofAspergillus niger

Cited by 19 publications

References 15 publications

Ultrastructural studies of induced morphogenesis byAspergillus parasiticus

Ultrastructural studies of induced morphogenesis byAspergillus parasiticus

The role of initial spore adhesion in pellet and biofilm formation in Aspergillus niger

Electron microscopic studies of saprobic and parasitic forms ofCoccidioides immitis

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