The fine structure of RNA-storing archaeocytes from gemmules of fresh-water sponges

1965 ◽  
Vol s3-106 (73) ◽  
pp. 99-114
Author(s):  
AUGUST RUTHMANN
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Fresh Water ◽  
Structural Integrity ◽  
Structural Aspect ◽  
Ground Substance ◽  
Annulate Lamellae ◽  
Golgi Bodies ◽  
High Concentrations ◽  
Cytoplasmic Ground Substance

Gemmules of fresh-water sponges contain about 500 binucleated cells (‘archaeocytes’) which are loaded with reserve substances including ribonucleoprotein, acidophilic proteins, lipids, and polysaccharides. These substances are utilized during the early phase of histogenesis after germination of the gemmules. Apart from the presence of reserve bodies, the basic fine structure of metabolically inactive archaeocytes within the closed system of a gemmule is not fundamentally different from actively metabolizing cells of rapidly growing tissues. In particular, ribosomes, endoplasmic reticulum, mitochondria, Golgi bodies, and RNA-containing nucleoli are present during inactivity as well as after germination and resumption of growth and synthesis. Changes in cellular fine structure after germination include an increased density of the cytoplasmic ground substance, the appearance of small vesicles in the vicinity of the Golgi bodies and of annulate lamellae and a large, cylindrical centriole near the nuclear envelope. Two general conclusions are drawn from these results. Neither the ultra-structural aspect of a cell nor the presence of high concentrations of RNA in cytoplasm and nucleolus is a valid indication of cellular activity or inactivity. The persistence of Golgi bodies and endoplasmic reticulum through long periods of inactivity shows that their structural integrity is not dependent upon continuous energy input, although these intracellular membrane systems are undoubtedly dynamic structures in metabolically active cells.

Organisation in the Structure of the Cytoplasmic Ground Substance

1978 ◽  
Vol 36 (3) ◽  
pp. 627-639
Author(s):  
K.R. Porter
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Random Distribution ◽  
Ground Substance ◽  
The Matrix ◽  
Cell Processes ◽  
Cytoplasmic Ground Substance

Most types of cells are known from their structure and overall form to possess a characteristic organization. In some instances this is evident in the non-random disposition of organelles and such system subunits as cisternae of the endoplasmic reticulum or the Golgi complex. In others it appears in the distribution and orientation of cytoplasmic fibrils. And in yet others the organization finds expression in the non-random distribution and orientation of microtubules, especially as found in highly anisometric cells and cell processes. The impression is unavoidable that in none of these cases is the organization achieved without the involvement of the cytoplasmic ground substance (CGS) or matrix. This impression is based on the fact that a matrix is present and that in all instances these formed structures, whether membranelimited or filamentous, are suspended in it. In some well-known instances, as in arrays of microtubules which make up axonemes and axostyles, the matrix resolves itself into bridges (and spokes) between the microtubules, bridges which are in some cases very regularly disposed and uniform in size (Mcintosh, 1973; Bloodgood and Miller, 1974; Warner and Satir, 1974).

CHANGES IN CELL FINE STRUCTURE OF LIMA BEAN AXES DURING EARLY GERMINATION

1966 ◽  
Vol 44 (3) ◽  
pp. 331-340 ◽  
Author(s):  
Shimon Klein ◽  
Yehuda Ben-Shaul
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Cell Walls ◽  
Lipid Droplets ◽  
Lima Bean ◽  
Amorphous Substance ◽  
Golgi Bodies ◽  
Early Germination ◽  
Almost All ◽  
Vacuolar Content

Changes in cell fine structure were studied in axes of green lima bean seeds soaked in water for 1–48 hours. At the beginning of the imbibition period the cortical and pith cells and to a smaller degree the cells of the future conductive tissues contain several vacuoles filled with an amorphous substance. Almost all of the cells contain lipid droplets arranged exclusively along cell walls. The endoplasmic reticulum appears in the form of long tubules, predominantly occupying the peripheral parts of the cell, surrounding the nucleus. A large concentration of ribosomes, mostly unattached, can be found in the cytoplasm. Similar particles make up the bulk of the nucleolus, but could not be found in plastids, which frequently contained starch, but were devoid of internal membranes. Only very few Golgi bodies occur. No changes in fine structure seem to occur during the first 4 hours of imbibition, but after 24 hours the lipid droplets and the vacuolar content have disappeared, the endoplasmic reticulum is more evenly distributed throughout the cells, and a large number of Golgi bodies can be seen.

Fine structure and early fertilization changes of the animal pole in eggs of the river lamprey, Lampetra fluviatilis

Development ◽  
1968 ◽  
Vol 19 (3) ◽  
pp. 319-326
Author(s):  
Lennart Nicander ◽  
Björn A. Afzelius ◽  
Inger Sjödén
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Electron Microscope ◽  
Marine Invertebrates ◽  
Bivalve Mollusc ◽  
Annulate Lamellae ◽  
Animal Pole ◽  
River Lamprey ◽  
Vertebrate Eggs

Fertilization is accompanied by changes in the structure of the egg cytoplasm (cf. Rothschild, 1958; Raven, 1961). At the level of fine structure such changes have mainly been studied in some marine invertebrates with small eggs that can easily be fertilized in vitro (Pasteels & de Harven, 1963; Schäfer, 1966). Vertebrate eggs are less favourable in this respect, but electron microscope studies have been made on eggs of mammals (Fléchon, 1966; Zamboni & Mastroianni, 1966; Zamboni, Mishell, Bell & Baca, 1966) and Xenopus (van Gansen, 1966). Changes generally observed soon after fertilization include the formation of polysomes or an increase in their number, a hypertrophy of the Golgi complexes, and the appearance of granulated endoplasmic reticulum and annulate lamellae. Afzelius (1957) observed the dispersal of mitochondria in fertilized sea-urchin eggs. Pasteels & de Harven (1963) reported that the structure and distribution of cytoplasmic organelles in eggs of the bivalve mollusc, Barnea Candida, are not altered by fertilization.

scholarly journals Stereological analysis of hepatic fine structure in the Fischer 344 rat. Influence of sublobular location and animal age.

1978 ◽  
Vol 78 (2) ◽  
pp. 319-337 ◽  
Author(s):  
D L Schmucker ◽  
J S Mooney ◽  
A L Jones
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Surface Area ◽  
Structural Parameters ◽  
Male Rats ◽  
Ground Substance ◽  
Stereological Analysis ◽  
Fischer 344 ◽  
Age Related ◽  
Old Rats

Stereological analysis of hepatic fine structure in Fischer 344 male rats at 1, 6, 10, 16, 20, 25, and 30 mo of age revealed differences in the amounts and distributions of hepatocellular organelles as a function of sublobular location or animal age. Between 1 and 16 mo of age, both the centrolobular and periportal hepatocytes increased in volume by 65 and 35%, respectively. Subsequently, the cell volumes declined until the hepatocytes of 30-mo-old rats approached the size of those found in the youngest animals. Regardless of animal age, the centrolobular cells were consistently larger than the corresponding periportal hepatocytes. The cytoplasmic and ground substance compartments reflected similar changes in their volumes, although there was no significant alteration in the nuclear volume. The volumes of the mitochondrial and microbody compartments increased and decreased concomitant with the changes in average hepatocyte size. Both lobular zones in the 30-mo-old rats contained significantly smaller relative volumes of mitochondria than similar parenchyma in 16-mo-old animals. The volume density of the dense bodies (lysosomes) increased markedly in both lobular zones between 1 and 30 mo of age, confirming reports of an age-dependent increase in this organelle. The surface area of the endoplasmic reticulum in the centrolobular and periportal hepatocytes reached its maximum level in the 10-mo-old rats and subsequently declined to amounts which approximated those measured in the 1-mo-old animals. This age-related loss of intracellular membrane is attributable to a significant reduction in the surface area of the smooth-surfaced endoplasmic reticulum (SER) in animals beyond 16 mo of age. The amount of rough-surfaced endoplasmic reticulum (RER) in the periportal parenchymal cells was unaffected by aging, but the centrolobular hepatocytes of 30-mo-old animals contained 90% more RER than similar cells in the youngest rats. The centrolobular parenchyma contained more SER and the portal zones more RER throughout the age span studied. These quantitative data suggest that (a) certain hepatic fine structural parameters undergo marked changes as a function of animal age, (b) there exists a gradient in hepatocellular fine structure across the entire liver lobule, and (c) there are remarkable similarities in hepatocyte ultrastructure between very young and senescent animals, including cell size and the amount of SER.

Fine structure of the thraustochytrid Ulkenia amoeboidea. II. The amoeboid stage and formation of zoospores

1982 ◽  
Vol 60 (7) ◽  
pp. 1103-1114 ◽  
Author(s):  
S. Raghu Kumar
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Fine Structure ◽  
Nuclear Division ◽  
Smooth Endoplasmic Reticulum ◽  
Dense Granule ◽  
Multivesicular Bodies ◽  
Golgi Bodies ◽  
Dense Bodies ◽  
Spindle Microtubules

In the thraustochytrid Ulkenia amoeboidea (Bahnweg & Sparrow) Gaertner the contents of the mature vegetative thallus escape from the cell wall in the form of a limax cell. The limax cell is covered by a layer of scales and possesses a nucleus, a paranuclear body, Golgi bodies, mitochondria, bands of smooth endoplasmic reticulum, vacuoles, multivesicular bodies, and cisternae with filamentous contents. The posterior end is filled with smooth endoplasmic reticulum and fusiform vesicles. The anterior end is organelle free and filled with cytoplasm with free ribosomes. Subspherical dense bodies, bounded by a single membrane, are present. The limax cell rounds up prior to mitosis and the Golgi bodies increase in number. During mitosis, the nuclear membrane breaks down totally. Chromosomes are not well defined. Spindle microtubules arise from the centriole and enter the nucleus. After nuclear division, the nuclear envelope is reformed. Cytokinesis is by cleavage into two cells, accompanied by formation of microtubules along the cleavage furrows. The zoospore possesses a nucleus, a paranuclear body, mitochondria, vesicles with presumptive mastigonemes and kinetosome rootlet microtubules and they are covered by a layer of scales. An electron-dense granule and two peripheral thickenings are present within the lumen of the kinetosome.

scholarly journals The Fine Structure of the Wheat Scutellum Before Germination

1972 ◽  
Vol 25 (1) ◽  
pp. 9 ◽  
Author(s):  
JG Swift ◽  
TP O'brien
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Coat Protein ◽  
Storage Protein ◽  
Cell Walls ◽  
Lipid Droplets ◽  
Light And Electron Microscopy ◽  
Ground Substance ◽  
Nuclear Chromatin

The structure of the cells of the scutellar epithelium and parenchyma is described and illustrated by light and electron microscopy of air-dry grains and compared with that seen in grains soaked for 3 hr. In the air-dry state, nuclear chromatin is strongly aggregated, mitochondria and plastids appear to be intact, endoplasmic reticulum is present but not abundant, and dictyosomes cannot be readily identified. The ground substance contains an abundance of free ribosomes which appear to coat protein bodies, lipid droplets, and mitochondria. In material soaked only for 3 hr, endoplasmic reticulum and dictyosomes are apparent, the nuclear chromatin has dispersed, and some mobilization of storage protein appears to have begun in the scutellar epithelium. No differences in fine structure of other organelles or in the cell walls could be detected.

scholarly journals OBSERVATIONS ON A SUBMICROSCOPIC BASOPHILIC COMPONENT OF CYTOPLASM

1953 ◽  
Vol 97 (5) ◽  
pp. 727-750 ◽  
Author(s):  
Keith R. Porter
Keyword(s):  
Endoplasmic Reticulum ◽  
Dark Field ◽  
Ground Substance ◽  
Adjacent Cell ◽  
Submicroscopic Structure ◽  
Dark Field Microscopy ◽  
Reticular System ◽  
Living Unit ◽  
Cytoplasmic Ground Substance

The cytoplasmic ground substance of animal tissue cells grown in vitro has been found by electron microscopy to contain, as a part of its submicroscopic structure, a complex reticulum of strands, to be referred to as the endoplasmic reticulum. It has been found in all types of cells extensively studied. The components of this reticular system vary considerably in size and form, apparently in some relation to physiological changes in the cell. Thus in one cell of a culture colony it may be finely divided into strands or canaliculi, 50 to 100 mµ in diameter, whereas in an adjacent cell of the same type the components of the reticulum may be relatively coarse, 600 mµ in diameter, and vesiculated. The membrane, which can be shown to limit the system and separate it from the rest of the ground substance, is similar in thickness to the plasma membrane surrounding the cell. Photomicrographs of living cells taken by phase contrast and dark field microscopy define a structure of similar form and indicate that the reticulum of the electron microscope image has its equivalent in the living unit. Where its component units are sufficiently large, a structure of identical form can be resolved by light microscopy in cells stained with hematoxylin or with toluidine blue. This indicated that the endoplasmic reticulum is to be identified with the basophilic or chromophilic component (the ergastoplasm) of the cytoplasm and that such properties of this component as have been determined by cytochemical methods, such as a high RNA content, may be assigned to this "submicroscopic" system.

scholarly journals Nonuniform distribution of sodium in the rat hepatocyte.

1976 ◽  
Vol 67 (4) ◽  
pp. 469-474 ◽  
Author(s):  
G Hooper ◽  
D A Dick
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Rat Hepatocytes ◽  
Nonuniform Distribution ◽  
Flame Photometry ◽  
Ground Substance ◽  
Rat Hepatocyte ◽  
Correlation Parameters ◽  
Cytoplasmic Ground Substance

The volume of the nucleus, endoplasmic reticulum (including Golgi complex), mitochondria, and cytoplasmic ground substance was measured in rat hepatocytes by stereological methods. The Na content was also measured by flame photometry. Variations in Na content correlated significantly with variations in volume of nucleus and endoplasmic reticulum. From the correlation parameters, Na concentrations were estimated as follows: nucleus, 108 mM; endoplasmic reticulum (ER) (including Golgie complex) 27 mM; cytoplasm (including and remaining organelles) 16 mM.

Insect frontal ganglion: fine structure of its neurosecretory cells in diapause and non-diapause larvae of Diatraea grandiosella

1975 ◽  
Vol 53 (8) ◽  
pp. 1093-1100 ◽  
Author(s):  
C.-M. Yin ◽  
G. M. Chippendale
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Neurosecretory Cells ◽  
Granular Endoplasmic Reticulum ◽  
Diatraea Grandiosella ◽  
Corn Borer ◽  
Golgi Bodies ◽  
Juvenile Hormone Mimic ◽  
Frontal Ganglion ◽  
Southwestern Corn Borer

The fine structure of the neurosecretory (NS) cells of the frontal ganglion (FG) of diapause and non-diapause mature larvae of the southwestern corn borer, Diatraea grandiosella, was compared. Two large (15- to 20-μm diam) NS cells are typically found in each FG. Their cytoplasm stained deeply purple with paraldehyde fuchsin and contained granules 1500–2500 Å in diameter. The granules in the NS cells of non-diapause larvae were often associated with Golgi bodies whereas those of the diapause larvae were associated with dilated cisternae of the granular endoplasmic reticulum. Fewer Golgi bodies were observed in sections of NS cells of the FG of diapause larvae than in those of non-diapause larvae. Sections prepared from diapause larvae obtained conventionally by exposure to low temperatures, and experimentally by treatment with a juvenile hormone mimic, gave similar results.Our findings show that granules accumulate in the perikaryon of the NS cells of the FG of diapause larvae and suggest that the granular endoplasmic reticulum is involved in their formation. The shutdown of the transport of these NS granules from the FG appears to be a factor in some yet to be determined phase of the neuroendocrine regulation of diapause.

scholarly journals The Fine Structure of the Parathyroid Gland

1958 ◽  
Vol 4 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Jerry Steven Trier
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Connective Tissue ◽  
Light Microscope ◽  
Parenchymal Cell ◽  
Cell Types ◽  
Perivascular Spaces ◽  
Chief Cells ◽  
Golgi Bodies ◽  
Endocrine Tissues

The fine structure of the parathyroid of the macaque is described, and is correlated with classical parathyroid cytology as seen in the light microscope. The two parenchymal cell types, the chief cells and the oxyphil cells, have been recognized in electron micrographs. The chief cells contain within their cytoplasm mitochondria, endoplasmic reticulum, and Golgi bodies similar to those found in other endocrine tissues as well as frequent PAS-positive granules. The juxtanuclear body of the light microscopists is identified with stacks of parallel lamellar elements of the endoplasmic reticulum of the ergastoplasmic or granular type. Oxyphil cells are characterized by juxtanuclear bodies and by numerous mitochondria found throughout their cytoplasm. Puzzling lamellar whorls are described in the cytoplasm of some oxyphil cells. The endothelium of parathyroid capillaries is extremely thin in some areas and contains numerous fenestrations as well as an extensive system of vesicles. The possible significance of these structures is discussed. The connective tissue elements found in the perivascular spaces of macaque parathyroid are described.

Sign in / Sign up

Export Citation Format

Share Document