Endoplasmic reticulum, vacuolation

Figure 1-7 Electron micrograph of a thin section of a young epidermal cell of a sunflower. The tissue was fixed and stained with uranyl acetate and lead citrate. Clearly visible are the nucleus (N), mitochondria (M), chloroplasts (C), a Golgi body dictyosome (G), endoplasmic reticulum, vacuole (V), cell wall, plasmodesmata, and cuticle (upper right, thin dark layer). Micrograph courtesy of H. T. Horner.

The ultramicrostructural alterations of the thyroid caused by overdosed iodine included a decrease of microvilli, dilation of rough endoplasmic reticulum, vacuolation of mitochondria, an increase in peroxidates and secondary lyso-somes, an increase in myelin-sheath structures in cytoplasm, and apoptosis and necrosis of thyroid epithelial cells. In contrast to Wistar rats, iodine excess could also cause infiltration of lymphocytes and proliferation of fibrous tissue in NOD. H-2 mice, which showed a positive correlation with the iodine dose. Similar results were found in other susceptible animals (Li et ai, 1993 Bagchi et at, 1995). When human thyroid cells were cultured with excessive iodine in vitro, Many et al. (1992) observed the same phenomenon under the electron microscope, such as dilated mitochondria, rough endoplasmic reticulum, increased secondary lysosomes, apoptosis and necrosis of epithelial cells, and a positive correlation between the ratio of apoptosis and iodine. 

Mimnaugh BG, Xu W, Vos M et al. (2006) Endoplasmic reticulum vacuolization and valosin-containing protein relocalization result from simultaneous hsp90 inhibition by geldanamycin and proteasome inhibition by velcade. Mol Cancer Resi(9), 667-681. 

Nucleus, Mitochondria, Chloroplasts, Endoplasmic reticulum, Golgi apparatus. Vacuole... 

Fig. 2.6 The moqjhological events of sporulation in Saccharomyces cerevisiae. (a) starved cell V, vacuole LG, lipid granule ER, endoplasmic reticulum CW, cell wall M, mitochondrion S, spindle pole SM, spindle microtubules N, nucleus NO, nucleolus, (b) Synaptonemal complex (SX) and development of polycomplex body (PB) along with division of spindle pole body in (c). (d) First meiotic division which is completed in (e). (f) Prepararation for meiosis II. (g) Enlargement of prospore wall, culminating in enclosure of separate haploid nuclei (h). (i) Spore coat (SC) materials produced and deposited, giving rise to the distinct outer spore coat (OSC) seen in the completed spores of the mature ascus (j). Reproduced from the review by Dickinson (1988) with permission from Blackwell Science Ltd.

Fig. 3 Representation of matiu-e secretory gland originated from C. sativa. The separate compartments of the glandular trichome are clearly shown, and the places where THC accumulates. Black areas nuclei, V vacuole, L vesicle, P plastid, ER endoplasmic reticulum. Picture obtained from http //www.hempreport.com/issues/17/malhodyl7.html...

Fig. 7.5. A schematic indication of some of the different membrane separated compartments in an advanced cell. PEROX is a peroxisome MITOCHLORO is either a mitochondrion or a chloroplast CHROMO is a vesicle of, say, the chromaffin granule ENDO is a reticulum, e.g. the endoplasmic reticulum. Other compartments are lysosomes, vacuoles, calcisomes and so on. Localised metal concentrations are shown. The figure is of a transverse section. To appreciate a cell fully it is necessary to have serial plane sections in parallel along the. "-direction.

Surprisingly, it turned out that some of peroxisomal membrane proteins are synthesized at the ER, cotranslationally. This seems a unique example that breaks the independence between the free ribosome system and the membrane-bound ribosome system (another example is found in a sorting mechanism into the vacuole). This phenomenon may be interpreted that the peroxisome may originate from the endoplasmic reticulum, evolutionally. 

Organelles Specific particles of membrane-bound organized living substances present in eukaryotic cells, such as the mitochondria the golgi apparatus endoplasmic reticulum lysomomes plastids and vacuoles. [NIH]... 

The most important membranes in animal cells are the plasma membrane, the inner and outer nuclear membranes, the membranes of the endoplasmic reticulum (ER) and the Golgi apparatus, and the inner and outer mitochondrial membranes. Lysosomes, peroxisomes, and various vesicles are also separated from the cytoplasm by membranes. In plants, additional membranes are seen in the plastids and vacuoles. All membranes show polarity—e., there is a difference in the composition of the inner layer (facing toward the cytoplasm) and the outer layer (facing away from it). 

The cell organellae in woody plants are the nucleus, mitochondrion, rough-endoplasmic reticulum (r-ER), smooth endoplasmic reticulum (s-ER), Golgi-body, plastid, vacuole, microbody, etc. Their functions are very complicated, and some have definite roles in the biosynthesis of cell-wall components. Hence, changes in size of cell organellae are likely to occur, since cell-wall composition depends upon the stage of wall development. 

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