Three-dimensional reconstruction of a pathogenic yeast<i>Exophiala dermatitidis</i>cell by freeze-substitution and serial sectioning electron microscopy

Yamaguchi, Masashi; Biswas, Sondip K.; Suzuki, Yasuyo; Furukawa, Hiromitsu; Takeo, Kanji

doi:10.1016/s0378-1097(02)01181-3

Cited by 26 publications

(13 citation statements)

References 11 publications

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“…This could explain why yeast walls are sometimes described as having a three-layered structure (34,35). A similar three-layered wall structure has been described for Exophiala dermatitidis (36,37). For a more detailed description of the molecular architecture of the walls of both S. cerevisiae and C. albicans and their wall proteomes, the reader is referred to recent reviews (31-34, 38, 39).…”

Section: Quantitative Analysis Of the Cell Walls Of S Cerevisiae Andmentioning

confidence: 85%

“…Our data can further be used as a starting point for a more quantitative analysis of other yeasts such as Candida glabrata (62) and other Candida spp., the industrial yeast Kluyveromyces lactis (85), and the fission yeast Schizosaccharomyces pombe (86,87). Interestingly, the haploid yeast form of E. dermatitidis (exponential-phase cells growing in rich medium) has been studied in depth by serial sectioning followed by a quantitative three-dimensional structural analysis (36,37). Although these two studies used freeze-substituted cells, presumably resulting in cell contraction, many of their measurements, such as the number of ribosomes/ cell (ϳ2 ϫ 10 5 ) (36), probably predict the corresponding values in haploid, exponential-phase S. cerevisiae cells reasonably well.…”

Section: Growth Rates and Surface Expansion Rates Of S Cerevisiae Anmentioning

confidence: 99%

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Cell Wall-Related Bionumbers and Bioestimates of Saccharomyces cerevisiae and Candida albicans

2014

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Bionumbers and bioestimates are valuable tools in biological research. Here we focus on cell wall-related bionumbers and bioestimates of the budding yeast Saccharomyces cerevisiae and the polymorphic, pathogenic fungus Candida albicans. We discuss the linear relationship between cell size and cell ploidy, the correlation between cell size and specific growth rate, the effect of turgor pressure on cell size, and the reason why using fixed cells for measuring cellular dimensions can result in serious underestimation of in vivo values. We further consider the evidence that individual buds and hyphae grow linearly and that exponential growth of the population results from regular formation of new daughter cells and regular hyphal branching. Our calculations show that hyphal growth allows C. albicans to cover much larger distances per unit of time than the yeast mode of growth and that this is accompanied by strongly increased surface expansion rates. We therefore predict that the transcript levels of genes involved in wall formation increase during hyphal growth. Interestingly, wall proteins and polysaccharides seem barely, if at all, subject to turnover and replacement. A general lesson is how strongly most bionumbers and bioestimates depend on environmental conditions and genetic background, thus reemphasizing the importance of well-defined and carefully chosen culture conditions and experimental approaches. Finally, we propose that the numbers and estimates described here offer a solid starting point for similar studies of other cell compartments and other yeast species.

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Section: Quantitative Analysis Of the Cell Walls Of S Cerevisiae Andmentioning

confidence: 85%

Section: Growth Rates and Surface Expansion Rates Of S Cerevisiae Anmentioning

confidence: 99%

Cell Wall-Related Bionumbers and Bioestimates of Saccharomyces cerevisiae and Candida albicans

2014

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“…Cells were collected by centrifugation, sandwiched between two 3-mm-diameter copper discs, and rapidly frozen by plunging into propane slush kept in liquid nitrogen (70). The discs were transferred to liquid nitrogen and separated to expose the cells.…”

Section: Methodsmentioning

confidence: 99%

Contribution of the Mannan Backbone of Cryptococcal Glucuronoxylomannan and a Glycolytic Enzyme ofStaphylococcus aureusto Contact-Mediated Killing ofCryptococcus neoformans

et al. 2007

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The fungal pathogen Cryptococcus neoformans is killed by the bacterium Staphylococcus aureus, and the killing is inhibited by soluble capsular polysaccharides. To investigate the mechanism of killing, cells in coculture were examined by scanning and transmission electron microscopy. S. aureus attached to the capsule of C. neoformans, and the ultrastructure of the attached C. neoformans cells was characteristic of dead cells. To identify the molecules that contributed to the fungal-bacterial interaction, we treated each with NaIO 4 or protease. Treatment of C. neoformans with NaIO 4 promoted adherence. It was inferred that cleavage of xylose and glucuronic acid side chains of glucuronoxylomannan (GXM) allowed S. aureus to recognize mannose residues in the backbone, which resisted periodate oxidation. On the other hand, treatment of S. aureus with protease decreased adherence, suggesting that protein contributed to attachment in S. aureus. In confirmation, side chain-cleaved polysaccharide or defined ␣-(133)-mannan inhibited the killing at lower concentrations than native GXM did. Also, these polysaccharides reduced the adherence of the two species and induced clumping of pure S. aureus cells. ␣-(133)-Mannooligosaccharides with a degree of polymerization (DP) of >3 induced cluster formation of S. aureus in a dose-dependent manner. Surface plasmon resonance analyses showed interaction of GXM and surface protein from S. aureus; the interaction was inhibited by oligosaccharides with a DP of >3. Conformations of ␣-(133) oligosaccharides were predicted. The three-dimensional structures of mannooligosaccharides larger than triose appeared curved and could be imagined to be recognized by a hypothetical staphylococcal lectin. Native polyacrylamide gel electrophoresis of staphylococcal protein followed by electroblotting, enzyme-linked immunolectin assay, protein staining, and N-terminal amino acid sequencing suggested that the candidate protein was triosephosphate isomerase (TPI). The enzymatic activities were confirmed by using whole cells of S. aureus. TPI point mutants of S. aureus decreased the ability to interact with C. neoformans. Thus, TPI on S. aureus adheres to the capsule of C. neoformans by recognizing the structure of mannotriose units in the backbone of GXM; we suggest that this contact is required for killing of C. neoformans.

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“…They were freeze-substituted in acetone containing 2% osmium tetroxide at -80°C for 2-3 days and embedded in epoxy resin 7,8 . Ultrathin sections were obtained using a diamond knife, stained with uranyl acetate and lead citrate 9 , and examined by a JEM 1200EX transmission electron microscope JEOL Ltd., Tokyo .…”

Section: Electron Microscopymentioning

confidence: 99%

Cytological Study of Cell Cycle of the Pathogenic Yeast Cryptococcus neoformans

Yamaguchi

Ohkusu

Biswas

et al. 2007

Nippon Ishinkin Gakkai Zasshi

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Cryptococcus neoformans is an opportunistic human pathogen belonging to basidiomycetous fungi and has unique properties in cell cycle progression. The purpose of this study was to measure the duration of the cell cycle in this yeast. Under standard liquid culture conditions 1% yeast extract, 1% polypeptone, and 1% glucose; 24°C; and 150 rpm , the doubling time of exponentially growing C. neoformans was 132 ± 16 min mean ± standard deviation , and the durations of the G1, S, G2, and M phases were about 71, 18, 25, and 18 min, respectively. DNA synthesis started before bud emergence, and finished by the time the size of the bud became 1/4 that of the mother cell. The doubling time of the daughter cells was about twice that of the mother cells. The spindle pole body was located on the outer nuclear envelope and showed a duplicated form from the G1 phase to the G2 phase. These data form a basis for further cell cycle study of C. neoformans.

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Three-dimensional reconstruction of a pathogenic yeastExophiala dermatitidiscell by freeze-substitution and serial sectioning electron microscopy

Cited by 26 publications

References 11 publications

Cell Wall-Related Bionumbers and Bioestimates of Saccharomyces cerevisiae and Candida albicans

Cell Wall-Related Bionumbers and Bioestimates of Saccharomyces cerevisiae and Candida albicans

Contribution of the Mannan Backbone of Cryptococcal Glucuronoxylomannan and a Glycolytic Enzyme ofStaphylococcus aureusto Contact-Mediated Killing ofCryptococcus neoformans

Cytological Study of Cell Cycle of the Pathogenic Yeast Cryptococcus neoformans

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