scholarly journals ELECTRON MICROSCOPE STUDIES ON THE CELLS OF THE MALPIGHIAN TUBULES OF THE GRASSHOPPER (ORTHOPTERA, ACRIDIDAE)

1955 ◽  
Vol 1 (3) ◽  
pp. 197-202 ◽  
Author(s):  
H. W. Beams ◽  
T. N. Tahmisian ◽  
R. L. Devine
Keyword(s):  
Electron Microscope ◽  
Cell Membrane ◽  
Cell Body ◽  
Basal Cell ◽  
Brush Border ◽  
Malpighian Tubules ◽  
Cell Cytoplasm ◽  
Small Bodies ◽  
Dense Cores ◽  
Basal Zone

For purposes of description, the cells of the Malpighian tubules of the grasshopper may be divided into basal, intermediate, and apical zones. The basal zone of the cell contains what appears to be an elaborate infolding of the cell membrane at the base. This condition results in the basal cell cytoplasm being divided into many compartments. The compartments contain mitochondria that are often arranged in rows. Other small bodies which possess relatively dense outer borders and less dense cores were observed within the compartments. These bodies are unidentified. The brush border of the apical zone contains a multitude of vertically arranged protoplasmic processes. Stages were found which suggest that the filamentous mitochondria migrate from the cell body to the base of the protoplasmic processes, where they enter them and move apically. Some of the mitochondria were observed at the very tips of the processes where they enlarge producing an accompanying bulging of the tips. This condition is interpreted as a stage in the pinching off of the mitochondria-laden tips of the protoplasmic processes.

scholarly journals Action of activated 27,000 Mr toxin from Bacillus thuringiensis var. israelensis on Malpighian tubules of the insect, Rhodnius prolixus

1989 ◽  
Vol 94 (3) ◽  
pp. 601-608
Author(s):  
S.H. Maddrell ◽  
J.A. Overton ◽  
D.J. Ellar ◽  
B.H. Knowles
Keyword(s):  
Bacillus Thuringiensis ◽  
Cell Membrane ◽  
Basal Cell ◽  
Time Course ◽  
Fluid Secretion ◽  
Rhodnius Prolixus ◽  
Malpighian Tubules ◽  
Bathing Solution ◽  
Concentrated Solutions ◽  
Intracellular Milieu

The action of activated 27,000 Mr toxin from Bacillus thuringiensis var. israelensis (Bti toxin) on Malpighian tubules of Rhodnius prolixus has been investigated. Its binding to the tubules is slowed by low temperature but is not prevented even at 0 degree C. The binding is less effective at pH 10 than at pH7. Pretreatment of the tubules with 0.1 mmol l-1 ouabain or bumetanide or 1 mumol l-1 5-hydroxytryptamine did not affect the toxicity of the toxin. The toxin causes very large changes in the trans-epithelial potential difference; it changes from 40 mV, lumen negative, often to more than 100 mV, lumen positive. This reflects an initial collapse of the potential of the basal cell membrane, followed by a large positive-going potential change at the luminal cell membrane. Just prior to the effects of the toxin on rapid fluid secretion, the basal cell membrane becomes permeable to sucrose molecules. Raffinose at 170 mmol l-1 in the bathing solution does not protect the tubules from Bti toxin action but dextran, Mr5000, at 60 mmol l-1 significantly delayed failure of fluid secretion and, even more, the onset of staining of the tubule cells with Trypan Blue. Exposing tubules to saline that is calcium-free and/or magnesium-free, or has a composition adjusted to be similar to that of the intracellular milieu, does not affect the time course of failure of fluid secretion induced by the toxin. There is no evidence that effective aggregates of Bti toxin molecules are formed in concentrated solutions.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals A NEW APICAL MICROTUBULE-ASSOCIATED ORGANELLE IN THE STERNAL GLAND OF ZOOTERMOPSIS NEVADENSIS (HAGEN), ISOPTERA

1965 ◽  
Vol 24 (2) ◽  
pp. 277-283 ◽  
Author(s):  
P. Satir ◽  
A. M. Stuart
Keyword(s):  
Electron Microscope ◽  
Cell Membrane ◽  
Cell Organelle ◽  
Sternal Gland ◽  
Opaque Zone ◽  
Cell Cytoplasm ◽  
Apical Portion ◽  
Smooth Membrane ◽  
Membrane Bound ◽  
Columnar Cells

The apical portion of the columnar cells of the sternal gland of the termite Zootermopsis nevadensis (Hagen) has been examined with the electron microscope. The cell surface abutting the cuticle is thrown into ridges upon which stand microvilli. Sections show a network of smooth membrane-bound cisternae penetrating the interior of the microvilli. At the bottom of the crevasses between the ridges, an inpocketing of the cell membrane is often found. This is surrounded by a 40-mµ electron-opaque zone that is the insertion of a 22-mµ microtubular component of the cell cytoplasm. The pouch-like structures and their associated microtubules are considered to represent a new cell organelle.

scholarly journals Two Atypical Enteropathogenic Escherichia coli Strains Induce the Production of Secreted and Membrane-Bound Mucins To Benefit Their Own Growth at the Apical Surface of Human Mucin-Secreting Intestinal HT29-MTX Cells

2010 ◽  
Vol 78 (3) ◽  
pp. 927-938 ◽  
Author(s):  
Mônica A. M. Vieira ◽  
Tânia A. T. Gomes ◽  
Antonio J. P. Ferreira ◽  
Terezinha Knöbl ◽  
Alain L. Servin ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Membrane ◽  
Brush Border ◽  
Apical Surface ◽  
Enteropathogenic Escherichia Coli ◽  
Typical Epec ◽  
Membrane Bound

ABSTRACT In rabbit ligated ileal loops, two atypical enteropathogenic Escherichia coli (aEPEC) strains, 3991-1 and 0421-1, intimately associated with the cell membrane, forming the characteristic EPEC attachment and effacement lesion of the brush border, induced a mucous hypersecretion, whereas typical EPEC (tEPEC) strain E2348/69 did not. Using cultured human mucin-secreting intestinal HT29-MTX cells, we demonstrate that apically aEPEC infection is followed by increased production of secreted MUC2 and MUC5AC mucins and membrane-bound MUC3 and MUC4 mucins. The transcription of the MUC5AC and MUC4 genes was transiently upregulated after aEPEC infection. We provide evidence that the apically adhering aEPEC cells exploit the mucins' increased production since they grew in the presence of membrane-bound mucins, whereas tEPEC did not. The data described herein report a putative new virulence phenomenon in aEPEC.

An Electron Microscope study of a Small Free-living Amoeba (Hartmanella astronyxis)

1959 ◽  
Vol s3-100 (49) ◽  
pp. 13-15
Author(s):  
K. DEUTSCH ◽  
M. M. SWANN
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Cell Membrane ◽  
Nuclear Membrane ◽  
Layered Structure ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Honeycomb Structure ◽  
Free Living ◽  
Free Living Amoeba

The fine structure of a species of small free-living amoeba, Hartmanella astronyxis, has been investigated. The mitochondria resemble those of other species of amoeba. Structureless bodies of about the same size as mitochondria are sometimes found in association with them. Double membranes are common in the cytoplasm, and may show granules along their outer borders. The nuclear membrane is a double-layered structure, with a honeycomb structure evident in tangential sections. The cell membrane is also double-layered, or occasionally multi-layered.

scholarly journals An Electron Microscope Study of the Source and Distribution of Ferritin in Hepatic Parenchymal Cells of the Newborn Rabbit

Blood ◽  
1960 ◽  
Vol 15 (4) ◽  
pp. 480-490 ◽  
Author(s):  
JAMES C. HAMPTON
Keyword(s):  
Electron Microscope ◽  
Microscope Study ◽  
Light Microscope ◽  
Electron Microscope Study ◽  
Hepatic Cell ◽  
Cell Cytoplasm ◽  
Electron Microscopic ◽  
Newborn Rabbit ◽  
Blue Reaction ◽  
Parenchymal Cells

Abstract Evidence that erythrocytes are phagocytized and dismantled by hepatic parenchymal cells in the newborn rabbit is presented. It is concluded that in these cells iron is recovered from disintegrating erythrocytes, synthesized into ferritin and released into the hepatic cell cytoplasm and into the biliary passages. These conclusions are based upon observations on the distribution of material giving the Prussian blue reaction in sections of liver as revealed by the light microscope and upon electron microscopic images of particles displaying the size, density and configuration of the ferritin molecule.

Sheaths of the Motor Axons of the Crab Carcinus

1964 ◽  
Vol s3-105 (70) ◽  
pp. 175-181
Author(s):  
G. A. HORRIDGE ◽  
R. A. CHAPMAN
Keyword(s):  
Cell Membrane ◽  
Glial Cell ◽  
Cross Section ◽  
Glial Cells ◽  
Fibrous Material ◽  
Motor Axons ◽  
Cell Cytoplasm ◽  
Fibrous Sheath ◽  
Outer Sheath ◽  
Sheath Structure

In crab leg nerves, the largest axons, which are the motor axons usually isolated for physiological experiments, have a sheath structure which is different from that in medium sized and smaller axons of the same nerve or of any other described nerves. Axons with a diameter over 20 µ have (a) an outer sheath, about 5µ thick, of wellspaced layers of alternating glial cell cytoplasm and extracellular fibrous material, formed from fewer cells than there are layers, and (b) an inner sheath of elongated cells which creep along the axon longitudinally and interdigitate where they meet, as seen 2 or 3 times round the outside of the membranes of axons in cross-section. Therefore, possible channels between inner glial cells are elongated and few. On these structural grounds, together with physiological evidence, they seem unlikely to be preferred pathways of diffusion of ions in crab axons. Smaller axons have simple sheaths; some occur in groups within a fibrous sheath; the thinnest axons frequently occur in bundles and have no glial cell membrane in contact with them.

Cytological and cytochemical studies of centrifuged eggs of the slug Avion ater rufus L.

Development ◽  
1972 ◽  
Vol 27 (1) ◽  
pp. 1-13
Author(s):  
A. H. Sathananthan
Keyword(s):  
Electron Microscope ◽  
Cell Membrane ◽  
Sea Urchin ◽  
Cell Organelles ◽  
Chemical Substances ◽  
Important Chemical ◽  
Equatorial Band ◽  
Hyaline Zone ◽  
Egg Cortex

The stratification of various cell organelles and of important chemical substances have been studied in the eggs of the slug, after moderate centrifugation. As in other molluscs the egg contents stratify typically into three well-defined zones - lipid, L hyaline and yolky zones - but a distinct equatorial band of inclusions consisting mainly of F phagosomes and associated lysosomes was detected in the most centrifugal region of the hyaline zone. The sub-stratification of various cell inclusions in their respective zones was determined in some detail. The role of the cell membrane and egg cortex in the redistribution of these inclusions and the nature of the ergastoplasm are discussed in the light of electron-microscope studies of eggs of this slug and of the sea urchin.

Quantitative ultrastructure and functional correlates in proximal tubule of Ambystoma and Necturus

1984 ◽  
Vol 246 (5) ◽  
pp. F710-F724 ◽  
Author(s):  
A. B. Maunsbach ◽  
E. L. Boulpaep
Keyword(s):  
Cell Membrane ◽  
Structure Function ◽  
Proximal Tubule ◽  
Basal Cell ◽  
Basolateral Membrane ◽  
Ambystoma Tigrinum ◽  
Solvent Interactions ◽  
Quantitative Ultrastructure ◽  
A Site ◽  
Lateral Cell

The functional properties of the proximal tubule in the salamander Ambystoma tigrinum have been well characterized but its ultrastructure has not been examined. We therefore analyzed the qualitative and quantitative ultrastructure of the proximal tubule in this species as a basis for structure-function correlations. In addition, a comparative study between species was performed between Ambystoma and Necturus. In Ambystoma the basal cell membrane but not the lateral cell membrane has a highly elaborate organization and is greatly amplified at the basal cell surface. Therefore, the bulk of the basolateral membrane does not face the lateral intercellular space but faces a basal extracellular labyrinth immediately adjacent to the peritubular space. We suggest that this intraepithelial compartment may serve as a site for solute-solvent interactions. The morphometric comparative analysis provides quantitative estimates of tubule dimensions, volume of cells and extracellular channels, areas of luminal, lateral, and basal cell membranes as well as averaged dimensions of the lateral intercellular spaces. Structure-function correlations show that when certain functional parameters are normalized on the basis of ultrastructural rather than epithelial dimensions the interspecies variability decreases.

starch grains in macerated cells

IAWA Journal ◽  
2014 ◽  
Vol 35 (2) ◽  
pp. 155-157
Author(s):  
Vinay R. Patel ◽  
Karumanchi S. Rao
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Crucial Role ◽  
Grain Shape ◽  
Cell Cytoplasm ◽  
Thin Sections ◽  
Starch Grains ◽  
Microscope Images ◽  
Starch Grain ◽  
Scanning Electron

A modified Jeffrey’s method for localization of starch grains in wood samples macerated between 15–25 °C is described here. Time and temperature played a crucial role in maintaining starch grain shape in cell cytoplasm. Starch grain shape in macerated xylem cells was confirmed by comparison with scanning electron microscope images and thin sections (10 to 15 μm thick) from the same wood samples.

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