Functional analysis of the baculovirus per os infectivity factors 3 and 9 by imaging the interaction between fluorescently labelled virions and isolated midgut cells

Baculovirus occlusion-derived viruses (ODVs) contain ten known per os infectivity factors (PIFs). These PIFs are crucial for midgut infection of insect larvae and form, with the exception of PIF5, an ODV entry complex. Previously, R18-dequenching assays have shown that PIF3 is dispensable for binding and fusion with midgut epithelial cells. Oral infection nevertheless fails in the absence of PIF3. PIF9 has not been analysed in much depth yet. Here, the biological role of these two PIFs in midgut infection was examined by monitoring the fate of fluorescently labelled ODVs when incubated with isolated midgut cells from Spodoptera exigua larvae. Confocal microscopy showed that in the absence of either PIF3 or PIF9, the ODVs bound to the brush borders, but the nucleocapsids failed to enter the cells. Finally, we discuss how the results obtained for PIF3 with dequenching assays and confocal microscopy can be explained by a two-phase fusion process.

Download Full-text

The role of Exocyst complex in the fusion process of KCa3.1 at the basolateral membrane of epithelial cells

The FASEB Journal ◽

10.1096/fasebj.2018.32.1_supplement.750.26 ◽

2018 ◽

Vol 32 (S1) ◽

Author(s):

Rachel E. Farquhar ◽

Fiona J. McDonald ◽

Kirk L. Hamilton

Keyword(s):

Epithelial Cells ◽

Basolateral Membrane ◽

Fusion Process ◽

Exocyst Complex

Download Full-text

The role of acid phosphatase in the fusion of the secondary palate

Development ◽

10.1242/dev.20.1.15 ◽

1968 ◽

Vol 20 (1) ◽

pp. 15-23

Author(s):

D. Angelici ◽

M. Pourtois

Keyword(s):

Electron Microscopy ◽

Acid Phosphatase ◽

Epithelial Cells ◽

Organ Culture ◽

Fusion Process ◽

Culture Methods ◽

Secondary Palate ◽

Subsequent Step ◽

Cell Layers

Complete closure of the secondary palate must progress through two consecutive events: the converging movement of the palatal shelves and their subsequent fusion at the line of contact. Each step is indispensable in normal palatal development since, theoretically, a palatal cleft might be the consequence of a failure of either. Until recently, the mechanisms of shelf movement received most attention (Peter, 1924; Lazarro, 1940; Walker & Fraser, 1956; Larsson, 1960). However, recent investigations have focused on the subsequent step, properly referred to as fusion. These studies, based on organ culture methods (Pourtois, 1966) and electron microscopy (Mato, Aikawa & Katahira, 1966; Farbman, 1967; Smiley & Dixon, 1967), have emphasized the complexity of the fusion process. This process may be viewed as a sequence of four interdependent events: (1) differentiation of the cell layers at the edge of the shelves resulting in the formation of a ‘zone of stickiness’ (Pourtois, 1968); (2) fusion of these differentiated epithelial cells leading to the formation of a laminated wall of epithelium between the shelves; (3) rupture of that partition permitting contact between the elements of the mesenchyme from either side; and (4) finally, degeneration of the epithelial remains of the seam marking the completion of the fusion process.

Download Full-text

Effect of Calcium on the Growth and Differentiation of Cultured Rat Esophageal Epithelial Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053383 ◽

1982 ◽

Vol 40 ◽

pp. 132-133

Author(s):

W.T. Gunning ◽

M.R. Marino ◽

M.S. Babcock ◽

G.D. Stoner

Keyword(s):

Epithelial Cells ◽

Cell Types ◽

Replication Rate ◽

Enzymatic Dissociation ◽

Growth Assay ◽

Epidermal Growth ◽

Fetal Bovine ◽

Esophageal Epithelial Cells ◽

Cellular Replication

The role of calcium in modulating cellular replication and differentiation has been described for various cell types. In the present study, the effects of Ca++ on the growth and differentiation of cultured rat esophageal epithelial cells was investigated.Epithelial cells were isolated from esophagi taken from 8 week-old male CDF rats by the enzymatic dissociation method of Kaighn. The cells were cultured in PFMR-4 medium supplemented with 0.25 mg/ml dialyzed fetal bovine serum, 5 ng/ml epidermal growth factor, 10-6 M hydrocortisone 10-6 M phosphoethanolamine, 10-6 M ethanolamine, 5 pg/ml insulin, 5 ng/ml transferrin, 10 ng/ml cholera toxin and 50 ng/ml garamycin at 36.5°C in a humidified atmosphere of 3% CO2 in air. At weekly intervals, the cells were subcultured with a solution containing 1% polyvinylpyrrolidone, 0.01% EGTA, and 0.05% trypsin. After various passages, the replication rate of the cells in PFMR-4 medium containing from 10-6 M to 10-3 M Ca++ was determined using a clonal growth assay.

Download Full-text

Adenomatoid Tumor of the Testis, A Mesonephric Hamartoma

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100065638 ◽

1971 ◽

Vol 29 ◽

pp. 318-319

Author(s):

Raoul Fresco ◽

Mary Chang-Lo

Keyword(s):

Electron Microscopy ◽

Epithelial Cells ◽

Fibrous Tissue ◽

Salient Feature ◽

Luminal Surface ◽

Adenomatoid Tumor ◽

Ultrastructural Studies ◽

Epithelial Origin ◽

Brush Borders ◽

Cell Processes

Confusion surrounds the nature of the “adenomatoid tumor” of the testis, as evidenced by the large number of synonyms which have been ascribed to it. Various authors have considered the tumor to be of endothelial, mesothelial or epithelial origin. There appears to be no controversy as to the stromal elements of the tumor, which consists mainly of smooth muscle and fibrous tissue. It is the irregular gland-like spaces which have given rise to the numerous theories as to its histogenesis, and even recent ultrastructural studies fail to agree on the origin of these structures.Electron microscopy of a typical intrascrotal adenomatoid tumor showed the gland-like spaces to be lined by epithelial cells (Fig. 1), rich in cytoplasmic tonofibrils and united to each other by numerous desmosomes (Fig. 2). The most salient feature of these epithelial cells was the presence on their luminal surface of numerous long and repeatedly branching microvillous structures of the type known as stereocilia (Fig. 3). These are extremely long slender cell processes which are as much as three to four times the length of those in brush borders.

Download Full-text