The Ultrastructure And Pathobiology Of Urinary Bladder Cancer
George T. Bryan, Samuel M. Cohen in The Pathology of Bladder Cancer, 2017
The Golgi apparatus of the mammalian urinary bladder consists of a complex membrane system (see Figure 5). Its degree of development and its location within the cell is different in the various cell layers.40,43 In basal cells, the Golgi complex is small and positioned laterally to the nucleus in the perinuclear cytoplasm. It consists of two to three curved parallel flattened vacuoles or cisternae that are often expanded at their ends. A few transport vesicles are associated with the concave inner surface of the stacks of cisternae. In the intermediate cell layer of normal urinary bladder epithelium, the Golgi complex is much larger and is often multicentric. Most of the Golgi fields are located in the perinuclear cytoplasm, facing the lumen of the bladder. Golgi complexes are more fully developed, as evidenced by increases in the lengths of the stacked lamellae. Transport vesicles are found along both the convex and the concave surfaces of the lamellae. In superficial cells, Golgi complexes may be located anywhere within the perinuclear cytoplasm, although a basal orientation is most common. Golgi complexes may occur singly or in several locations within the perinuclear cytoplasm. Transport vesicles are numerous in superficial cells.
The Transfer of Passive and Active Immunity
Gérard Chaouat in The Immunology of the Fetus, 2020
In the human, a similar pathway is likely to effect transport across the syncytiotro-phoblast. Ockleford27 and Ockleford and Whyte28 found large numbers of coated vesicles (Figure 3) located in a position (the cell surface) in which uptake would be possible. Coated vesicle transport systems are typically vehicles for receptor-mediated uptake of proteins and particles.29-31 These coated vesicles formed in the membrane previously shown to be bearing Fc receptors. Whyte32 discovered the glycocalyx lining the coated pits and vesicles of the human placenta to be rich in galactosamine and poor in sialic acid, which is consistent with the finding of Niezgodka et al.17 that the binding of IgG to human placental membrane is chaotrope sensitive, yet neuraminidase insensitive.
Beyond Enzyme Kinetics
Clive R. Bagshaw in Biomolecular Kinetics, 2017
where [X]i and [X]o represent the concentration of component X on either side of the membrane. Pumping components against the concentration gradient requires an energy source, such as ATP hydrolysis. Several decades ago, the kinetics of pump proteins were better understood than channel proteins because the associated ATPase activity provided a convenient assay for both purification and characterization. Such proteins, when solubilized using detergents, can be investigated using methods developed for ordinary enzymes. In order to measure transport activity, the protein under investigation can be incorporated into a lipid vesicle. The substrate to be transported, typically radiolabeled, is added to the external solution and the sample is rapidly filtered and washed to determine the amount of substrate trapped within the vesicle [259]. Continuous assays have been developed using fluorescence pH indicators to monitor uptake weak acids or bases [260].
The neurosciences at the Max Planck Institute for Biophysical Chemistry in Göttingen
Published in Journal of the History of the Neurosciences, 2023
The early 1990s were the “golden years” for the discovery of proteins, which play a decisive role in binding vesicles to the outer cell membrane and in the subsequent fusion and secretion (Südhof 2014). Three groups made significant contributions here, with different model systems and working methods. James E. Rothman and colleagues studied intracellular vesicle transport in a cell-free assay with the biochemical method. They found NSF, SNAP, and named the proteins that are involved in binding the vesicle to the cell membrane the SNARE complex (Söllner et al. 1993). Randy W. Schekman and his colleagues used genetic screens to study yeast mutants in which the secretion was impaired. They cloned the corresponding gene and discovered the biochemical reactions that play a role in secretion. Thomas C. Südhof, Pietro de Camilli, and Reinhard Jahn researched the proteins that control the fusion of the vesicles with the cell membrane in nerve cells, contributing to the release of neurotransmitters using biochemical, genetic, physiological, and electron-microscopic methods. All three groups discovered similar proteins and mechanisms, which shows that secretion is an evolutionarily old and conserved mechanism (Bennett and Scheller 1993).
Encounters with adenovirus
Published in Upsala Journal of Medical Sciences, 2019
Fewer changes in cellular gene expression take place at 36 hpi when the infection has proceeded beyond the late phase and suppression is more pronounced (Figure 3). The most significant function of the up-regulated genes is protein translation, including genes for ribosomal proteins, translation initiation factors, and translation elongation factors. Genes involved in the generation of metabolites and energy, as well as oxidation/reduction, also become evident. The most outstanding function of the suppressed genes is the cellular macromolecule catabolic process including numerous genes mediating ubiquitination and subsequent proteasomal degradation. Another important function is signal transduction, involved in vesicle transport. At 36 hpi, different sets of TF binding sites are significant in the up-regulated genes, including SP1, STRA13, and NF-Y, in addition to GABP, while the binding sites for E2F become less important.
Copper oxide nanoparticles alter cellular morphology via disturbing the actin cytoskeleton dynamics in Arabidopsis roots
Published in Nanotoxicology, 2020
Honglei Jia, Sisi Chen, Xiaofeng Wang, Cong Shi, Kena Liu, Shuangxi Zhang, Jisheng Li
In plants, it has been reported that endocytosis may be an important pathway for uptake of NPs (Wang et al. 2012). The endosome is a vesicle structure, which is the main transport carrier for endocytosis in eukaryotic cells. The endocytosis inhibitor markedly decreased the accumulation of carbon nanotubes (SWNT) in tobacco cells (Lin et al. 2009). Our study observed that CuO NPs may enter the root tip cell through endocytosis and form black particles (Figure 1(b); Supplementary Figure S3). This result is similar to the uptake of CuO NPs in maize cells (Wang et al. 2012). CuO NPs treatment also caused the slight accumulation of copper in shoot (Figure 1(a)), which resulted in the low translocation rate of CuO NPs treatment compared with the treatment of Cu2+. However, black particles were not found in leaves, and the phenotype of mesophyll cells did not change (Figure 1(d)). These data implied that the transfer ability of CuO NPs was weak (Figure 1(a)). The most probable reason for this weakness is that CuO NPs fuze with the endosome but not directly enter into the cytoplasm. Therefore, root cells were the main target of CuO NP toxicity in Arabidopsis.
Related Knowledge Centers
- Cell Biology
- Lipid Bilayer
- Liposome
- Cell Membrane
- Lysosome
- Exocytosis
- Cell
- Endocytosis
- Unilamellar Liposome
- Lamellar Phase