Reevaluation of the effect of lysoyzme onEscherichia coli employing ultrarapid freezing followed by cryoelectronmicroscopy or freeze substitution

Wild, P.; Gabrieli, Arianna; Schraner, Elisabeth M.; Pellegrini, Antonio; Thomas, Ursula; Frederik, PM Peter; Stuart, Marc C. A.; Fellenberg, R. von

doi:10.1002/(sici)1097-0029(19971101)39:3<297::aid-jemt8>3.0.co;2-h

Cited by 44 publications

(36 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…However, the cell wall structure of P. kessleri was barely visible, not only in young autospores but also in adult cells, because of low contrast (Neˇmkova´and Kalina 2000). Conventional specimen preparation techniques for electron microscopy have several disadvantages when the objective is to preserve fine structural details (Steinbrecht 1993;Wild et al 1997;Lonsdale et al 1999). In this study, we used rapid freezing and freeze substitution methods for electron microscopy to show that cell wall structure in P. kessleri differed from that of the other three Chlorella species, C. vulgaris, C. sorokiniana, and C. lobophora.…”

Section: Discussionmentioning

confidence: 99%

“…This is impossible with chemical fixatives since the cell's reaction to the fixatives is relatively slow (Hayat 1989;Wild et al 1997). In particular, rapid freezing followed by freeze substitution results in the retention of lipoidal subcellular components and preserves both the cell membranes and the cytoplasmic components of the cell (Nicolas and Bassot 1993;Hippe-Sanwald 1993;Wild et al 1997). This technique preserves cells in a form close to that of living cells and consequently allows the observation of fine cell structures.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Late type of daughter cell wall synthesis in one of the Chlorellaceae, Parachlorella kessleri (Chlorophyta, Trebouxiophyceae)

Yamamoto

Kurihara

Kawano

2005

Planta

View full text Add to dashboard Cite

Autosporulation is a common mode of propagation for unicellular algae. Autospore-forming species of Chlorellaceae, Chlorella vulgaris Beijerinck, C. sorokiniana Shihira et Krauss, C. lobophora Andreyeva, and Parachlorella kessleri (Fott et Nováková) Krienitz et al. have glucosamine as the main constituent of their rigid cell wall. Recent phylogenetic analyses have showed that the Chlorellaceae divided into two sister groups: the Chlorella-clade and the Parachlorella-clade. We compared the cell wall structure and synthesis of the daughter cell wall in the four species by electron microscopy using rapid freezing and freeze substitution methods. The cell wall of C. vulgaris, C. sorokiniana, and C. lobophora consisted of an electron-dense thin layer with an average thickness of 17-20, 22, and 19 nm, respectively. In these three species, daughter cell wall synthesis occurred on the outer surface of the plasma membrane in the early cell-growth phase. The cell wall of P. kessleri, however, was electron-transparent and 54-59 nm in thickness. Ruthenium red staining of P. kessleri indicated that ruthenium-red-specific polysaccharides accumulated over the outer surface of the plasma membrane. Immunoelectron microscopic observation with an anti-beta-1, 3-glucan antibody and staining with wheat germ agglutinin (WGA) indicated that the cell wall contained beta-1, 3-glucan and WGA specific N-acetyl-beta-D-glucosamine. In P. kessleri, daughter cell wall synthesis began after successive protoplast division. The daughter cell wall synthesis during autosporulation in the four species of Chlorellaceae can be classified into two types-the early and the late types.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Late type of daughter cell wall synthesis in one of the Chlorellaceae, Parachlorella kessleri (Chlorophyta, Trebouxiophyceae)

Yamamoto

Kurihara

Kawano

2005

Planta

View full text Add to dashboard Cite

show abstract

“…However, the conventional techniques used to prepare specimens for electron microscopy have several disadvantages when the objective is to preserve fine structural details (Steinbrecht 1993;Wild et al 1997;Lonsdale et al 1999). By contrast, rapid freezing fixation arrests intracellular movement in milliseconds, which is impossible with chemical fixatives, as their reaction is very slow (Hayat 1989;Wild et al 1997). In particular, rapid freezing followed by freeze substitution results in the retention of lipoidal subcellular components.…”

Section: Introductionmentioning

confidence: 99%

Regeneration and maturation of daughter cell walls in the autospore-forming green alga Chlorella vulgaris (Chlorophyta, Trebouxiophyceae)

et al. 2004

View full text Add to dashboard Cite

Cell-wall synthesis in Chlorella vulgaris, an autospore-forming alga, was observed using the cell wall-specific fluorescent dye Fluostain I. The observation suggested two clearly distinguishable stages in cell-wall synthesis: moderate synthesis during the cell-growth process and rapid synthesis at the cell-division stage. We used electron microscopy to examine the structural changes that occurred with growth in the premature daughter cell wall during the cell-growth and cell-division phases. The cell began to synthesize a new daughter cell wall shortly after its release from the autosporangium. A very thin daughter cell wall, with a thickness of about 2 nm, was formed inside the mother cell wall and completely enveloped the outer surface of the plasma membrane of the cell. The daughter cell wall gradually increased in thickness from 2 to 3.8 nm. During the protoplast-division phase in the cell-division stage, the daughter cell wall expanded on the surface of the invaginating plasma membrane of the cleavage furrow, accompanied by active synthesis of the cell wall, which increased in thickness from 3.8 to 6.1 nm. The daughter cell matured into an autospore while completely enclosed by its own thickening (from 6.1 to 17 nm) wall. Finally, the released daughter cell was enclosed by its own cell wall after the mother cell wall burst. The daughter cell with mature wall thickness (17-21 nm) emerged as a small, but complete, autospore.

show abstract

“…In an attempt to gain more detailed information on interactions between the "primary" envelope and the outer nuclear membrane, we employed a technique that allows arresting of cellular processes in the range of milliseconds (38) and that keeps membranes in place even though they are disintegrating (60). Instead of fusion events at the outer nuclear membrane, we found (i) capsids budding from the cytoplasm into the perinuclear space (62) and (ii) impaired nuclear pores with capsids entering the cytoplasmic matrix in bovine herpesvirus 1 (BHV-1)-infected cells (59).…”

mentioning

confidence: 99%

Herpes Simplex Virus 1 Envelopment Follows Two Diverse Pathways

Leuzinger¹,

Ziegler

Schraner³

et al. 2005

J Virol

106

View full text Add to dashboard Cite

Herpesvirus envelopment is assumed to follow an uneconomical pathway including primary envelopment at the inner nuclear membrane, de-envelopment at the outer nuclear membrane, and reenvelopment at the trans-Golgi network. In contrast to the hypothesis of de-envelopment by fusion of the primary envelope with the outer nuclear membrane, virions were demonstrated to be transported from the perinuclear space to rough endoplasmic reticulum (RER) cisternae. Here we show by high-resolution microscopy that herpes simplex virus 1 envelopment follows two diverse pathways. First, nuclear envelopment includes budding of capsids at the inner nuclear membrane into the perinuclear space whereby tegument and a thick electron dense envelope are acquired. The substance responsible for the dense envelope is speculated to enable intraluminal transportation of virions via RER into Golgi cisternae. Within Golgi cisternae, virions are packaged into transport vacuoles containing one or several virions. Second, for cytoplasmic envelopment, capsids gain direct access from the nucleus to the cytoplasm via impaired nuclear pores. Cytoplasmic capsids could bud at the outer nuclear membrane, at membranes of RER, Golgi cisternae, and large vacuoles, and at banana-shaped membranous entities that were found to continue into Golgi membranes. Envelopes originating by budding at the outer nuclear membrane and RER membrane also acquire a dense substance. Budding at Golgi stacks, designated wrapping, results in single virions within small vacuoles that contain electron-dense substances between envelope and vacuolar membranes.Much controversy has arisen about the pathway of herpesvirus capsids from their nuclear origin to the site of their release into the extracellular space (e.g., see references 4, 13, 19, 50, 52, 53, 55, and 56). The current widely accepted view suggests the formation of primary virions comprising capsid, primary tegument, and a primary envelope that originates by budding at the inner nuclear membrane into the perinuclear space (37). For de-envelopment, the primary envelope is assumed to be inserted into the outer nuclear membrane by fusion, releasing capsid and the primary tegument into the cytoplasm (14). In contrast to de-envelopment, many investigations clearly demonstrate that "primary" virions are transported from the perinuclear space into rough endoplasmic reticulum (RER) cisternae (12,15,45,51,52,58,62) and that "primary" wild-type virions can accumulate within the perinuclear space-RER compartment (55). Intraluminal accumulations of virions have also been explained as a failure in deenvelopment, e.g., due to the lack of US3 protein in pseudorabies virus (25). The de-envelopment theory also does not consider that membrane fusion is a fast but well-studied process starting by close apposition of the membranes to allow fusion followed by pore formation (24,27,32,36). Recognizing close apposition and pore formation is imperative to distinguishing fusion from budding and fission. To our knowledge, pore formation between "prim...

show abstract

Reevaluation of the effect of lysoyzme onEscherichia coli employing ultrarapid freezing followed by cryoelectronmicroscopy or freeze substitution

Cited by 44 publications

References 29 publications

Late type of daughter cell wall synthesis in one of the Chlorellaceae, Parachlorella kessleri (Chlorophyta, Trebouxiophyceae)

Late type of daughter cell wall synthesis in one of the Chlorellaceae, Parachlorella kessleri (Chlorophyta, Trebouxiophyceae)

Regeneration and maturation of daughter cell walls in the autospore-forming green alga Chlorella vulgaris (Chlorophyta, Trebouxiophyceae)

Herpes Simplex Virus 1 Envelopment Follows Two Diverse Pathways

Contact Info

Product

Resources

About