Electron Microscopic Characterization of Insect Hemocytes

Author(s):  
Gertraude Wittig

The fine structure of insect hemocytes has been the subject of very few investigations. In particular, the hemocytes of Lepidoptera have received almost no attention. The study presented here was carried out on the armyworm, Pseudaletia unipuncta. Hemocytes of the larva were fixed 2 to 4 days after molt to the sixth instar and studied in ultrathin sections.Microplasmatocytes (Fig. 1) were the most important phagocytes of army-worm hemolymph. They were relatively small, spherical cells with a small, round or lobed nucleus. Distensions of the perinuclear cisterna (p) were frequent and sometimes continuous with the rough endoplasmic reticulum (e). The latter formed greatly distended cisternae which almost filled the whole cytoplasm. The cisternae contained an amorphous material which appeared to be condensed in certain sacs (at e). Mitochondria (m) were rare, and they had tubular cristae. Up to four Golgi complexes (g) were identified in a microplasmatocyte section. Structured granules (sg) were specific for this cell type. Microfibrils (f) traversed the whole cytoplasm but were most frequent around the nucleus (N) and under the cell membrane.

Author(s):  
J. P. Petrali ◽  
E. J. Donati ◽  
L. A. Sternberger

Specific contrast is conferred to subcellular antigen by applying purified antibodies, exhaustively labeled with uranium under immunospecific protection, to ultrathin sections. Use of Seligman’s principle of bridging osmium to metal via thiocarbohydrazide (TCH) intensifies specific contrast. Ultrathin sections of osmium-fixed materials were stained on the grid by application of 1) thiosemicarbazide (TSC), 2) unlabeled specific antiserum, 3) uranium-labeled anti-antibody and 4) TCH followed by reosmication. Antigens to be localized consisted of vaccinia antigen in infected HeLa cells, lysozyme in monocytes of patients with monocytic or monomyelocytic leukemia, and fibrinogen in the platelets of these leukemic patients. Control sections were stained with non-specific antiserum (E. coli).In the vaccinia-HeLa system, antigen was localized from 1 to 3 hours following infection, and was confined to degrading virus, the inner walls of numerous organelles, and other structures in cytoplasmic foci. Surrounding architecture and cellular mitochondria were unstained. 8 to 14 hours after infection, antigen was localized on the outer walls of the viral progeny, on cytoplasmic membranes, and free in the cytoplasm. Staining of endoplasmic reticulum was intense and focal early, and weak and diffuse late in infection.


1961 ◽  
Vol 11 (2) ◽  
pp. 333-347 ◽  
Author(s):  
Susumu Ito

An electron microscopic survey has been made of the gastric parietal or oxyntic cell of the human, cat, beaver, dog, hamster, rat, mouse, and bat, and of the corresponding cell type in two species of frog, two species of toad, and the horned lizard. A feature consistently found in the parietal cells of the mammals or their equivalent in the lower vertebrates is the agranular endoplasmic reticulum, which takes the form of branching and anastomosing small tubules approximately 200 to 500 A in diameter, sometimes expanded into flattened cisternae. In mammalian parietal cells this form of the endoplasmic reticulum is found only in limited amounts, but in the corresponding secretory cells of the amphibia and reptilia the tubular agranular reticulum is abundant. It is believed to comprise a more or less continuous system of channels, but owing to their tortuous course only short profiles are seen in thin sections. Immediately subjacent to the plasmalemma at the free surface, the cytoplasm is relatively free of organelles but is occasionally traversed by the agranular reticulum, which appears to be continuous at some points with the cell surface. The possible participation of the agranular endoplasmic reticulum in hydrochloric acid secretion is discussed.


1989 ◽  
Vol 17 (4_part_2) ◽  
pp. 782-788 ◽  
Author(s):  
Stephen K. Durham ◽  
Abraham Brouwer

Recent results (3) indicate that 200 mg 3,4,3′,4′-tetrachlorobiphenyl induces hepatomegaly accompanied by significant decreases in serum and hepatic retinoid content and hepatocyte morphologic alterations of proliferated and vesiculated endoplasmic reticulum and megamitochondria with paracrystalline inclusions. There was also an associated change in the number, size, and distribution of lipid droplets in hepatocytes and fat-storing cells. Electron microscopic autoradiographic techniques were utilized to determine the cellular and subcellular distribution of 3H-3,4,3′,4′-tetrachlorobiphenyl (3H-TCB) in the adult rat liver and determine if there is any relationship between subcellular morphologic change and radiolabel localization. Adult female WAG/Rij rats received a single intraperitoneal injection of 200 mg TCB/kg containing 1.85 mCi of 3H-TCB and were sacrificed at 1, 3, 7, and 14 days following exposure. The vast majority of 3H-TCB-derived radioactivity was located in the hepatocyte at all time points examined, ranging from 79–86% of the total number of autoradiographic grains counted over the liver cells. Sequential order of radiolabel localization per liver cell type at 1, 3, and 7 days was hepatocyte > > > Kupffer cell > fat-storing cell > endothelial cell. At day 14, the sequential order of radiolabel localization per liver cell type was hepatocyte > > > fat-storing cell > Kupffer cell > endothelial cell, which indicates that there was some shift movement of label over time. The lipid droplet, mitochondria, and endoplasmic reticulum were the subcellular structures or organelles of hepatocytes having the highest number of 3H-TCB-derived grains at all time periods examined. The predominant morphological alterations induced following TCB intoxication were observed in these organelles. The results of this study suggests that there is an association between TCB localization and morphologic change induced in mitochondria and endoplasmic reticulum of hepatocytes following TCB exposure.


1978 ◽  
Vol 26 (12) ◽  
pp. 1103-1108 ◽  
Author(s):  
M H Greider ◽  
D J Gersell ◽  
R L Gingerich

The F cell of the dog pancreas has been identified as the specific cell type containing pancreatic polypeptide. This localization of pnacreatic polypeptide was accomplished by immunocytochemical staining of ultrathin sections and direct electron microscopic identification. Verification of the specificity of the reaction was obtained by blocking experiments on serial sections of the same cell. It is proposed that the name F cell be used for defining in all species the islet cell that contains pancreatic polypeptide.


1955 ◽  
Vol s3-96 (34) ◽  
pp. 151-159
Author(s):  
GEORGE A. EDWARDS ◽  
HELMUT RUSKA

Electron microscopic observations on ultrathin sections of the red thoracic flightmuscles and white leg muscles of Hydrophilus and Dytiscus are reported. In red muscle-fibres with high values in frequency of contraction, oxygen consumption, and dehydrogenase activity, the single fibrils are completely surrounded by huge mitochondria. Tracheoles penetrate the sarcolemma and supply the mitochondria with oxygen by intracellular branches. In the less active white muscle fibres, mitochondria are found irregularly scattered between the fibrils or along the I band. The intracellular tracheolization is sparse but an endoplasmic reticulum is widely spread between the synfibrillar contractile material. The same muscles of the two insects differ considerably in detail.


1968 ◽  
Vol 38 (2) ◽  
pp. 392-402 ◽  
Author(s):  
Martha E. Fedorko ◽  
James G. Hirsch ◽  
Zanvil A. Cohn

Continuous phase-contrast observations have been made on macrophages following exposure to chloroquine. The initial abnormality is the appearance in the Golgi region of small vacuoles with an intermediate density between that of pinosomes and granules. Over the course of 1–2 hr these vacuoles grow larger and accumulate amorphous material or lipid. Pinosomes or granules frequently fuse with the toxic vacuoles. Chloroquine derivatives can be seen by fluorescence microscopy; the drug is rapidly taken up by macrophages and localized in small foci in the Golgi region. Chloroquine continues to produce vacuoles when pinocytosis is suppressed. Electron microscopic studies of chloroquine effects on macrophages preincubated with colloidal gold to label predominately pinosomes or granules suggest that toxic vacuoles can arise from unlabeled organelles. Later vacuoles regularly acquire gold label, apparently by fusion, from both granules and pinosomes. L cells also develop autophagic vacuoles after exposure to chloroquine. Smooth endoplasmic reticulum apparently is involved early in the autophagic process in these cells. Information now available suggests an initial action of chloroquine on Golgi or smooth endoplasmic reticulum vesicles, and on granules, with alterations in their membranes leading to fusion with one another and with pinosomes.


1984 ◽  
Vol 32 (1) ◽  
pp. 117-121 ◽  
Author(s):  
C D Figueroa ◽  
I Caorsi ◽  
J Subiabre ◽  
C P Vío

The cellular and subcellular localization of immunoreactive kallikrein was studied in the rat kidney using the peroxidase-antiperoxidase (PAP) method for the electron microscope. The effect of various tissue-processing protocols on ultrastructural preservation and immunocytochemical staining was evaluated by fixing kidneys with four different mixtures. The tissues were immunostained and further stained with OsO4 or silver methenamine. The best ultrastructural and immunocytochemical staining was obtained with Zamboni's-glutaraldehyde fixative. The kallikrein-immunoreactive cell type was identified, according to its localization and ultrastructural features, as the connecting-tubule cell. Immunoreactive kallikrein was concentrated mainly in the upper one-third of the cell and at both sides of the nuclei, and to a less extent was associated with the plasma membranes and basolateral infoldings. The immunoreactivity was related to free polyribosomes, the rough endoplasmic reticulum (RER), and the Golgi complex, suggesting that kallikrein is actively synthesized in this particular type of cell.


1961 ◽  
Vol 11 (3) ◽  
pp. 627-649 ◽  
Author(s):  
H. Robert Dudley ◽  
David Spiro

An electron microscopic study of Araldite-embedded, undecalcified human woven and chick lamellar bone is presented. The fine structure of the cells of bone in their normal milieu is described. Active osteoblasts possess abundant granular endoplasmic reticulum, numerous small vesicles, and a few secretion droplets. Their long cytoplasmic processes penetrate the osteoid. The transition of osteoblasts into osteoid osteocytes and then into osteocytes is traced and found to involve a progressive reduction of cytoplasmic organelles. Adjoining the osteocytes and their processes is a layer of amorphous material which is interposed between the cell surfaces and the bone walls of their respective cavities. Osteoclasts contain numerous non-membrane-associated ribosomes, abundant mitochondria, and little granular endoplasmic reticulum, thus differing markedly from other bone cells. The brush border is a complex of cytoplasmic processes adjacent to a resorption zone in bone. No unmineralized collagen is seen at resorption sites and it appears that collagen is removed before or at the time of mineral solution. All bone surfaces are covered by cells, some of which lack distinctive qualities and are designated endosteal lining cells. The structure of osteoid, bone, and early mineralization sites is illustrated and discussed.


Author(s):  
Kosuke Ueda ◽  
Hiroto Washida ◽  
Nakazo Watari

IntroductionHemoglobin crystals in the red blood cells were electronmicroscopically reported by Fawcett in the cat myocardium. In the human, Lessin revealed crystal-containing cells in the periphral blood of hemoglobin C disease patients. We found the hemoglobin crystals and its agglutination in the erythrocytes in the renal cortex of the human renal lithiasis, and these patients had no hematological abnormalities or other diseases out of the renal lithiasis. Hemoglobin crystals in the human erythrocytes were confirmed to be the first case in the kidney.Material and MethodsTen cases of the human renal biopsies were performed on the operations of the seven pyelolithotomies and three ureterolithotomies. The each specimens were primarily fixed in cacodylate buffered 3. 0% glutaraldehyde and post fixed in osmic acid, dehydrated in graded concentrations of ethanol, and then embedded in Epon 812. Ultrathin sections, cut on LKB microtome, were doubly stained with uranyl acetate and lead citrate.


Author(s):  
G. Rowden ◽  
M. G. Lewis ◽  
T. M. Phillips

Langerhans cells of mammalian stratified squamous epithelial have proven to be an enigma since their discovery in 1868. These dendritic suprabasal cells have been considered as related to melanocytes either as effete cells, or as post divisional products. Although grafting experiments seemed to demonstrate the independence of the cell types, much confusion still exists. The presence in the epidermis of a cell type with morphological features seemingly shared by melanocytes and Langerhans cells has been especially troublesome. This so called "indeterminate", or " -dendritic cell" lacks both Langerhans cells granules and melanosomes, yet it is clearly not a keratinocyte. Suggestions have been made that it is related to either Langerhans cells or melanocyte. Recent studies have unequivocally demonstrated that Langerhans cells are independent cells with immune function. They display Fc and C3 receptors on their surface as well as la (immune region associated) antigens.


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