scholarly journals THE ABSORPTION OF FAT BY INTESTINE OF GOLDEN HAMSTER IN VITRO

1963 ◽  
Vol 17 (3) ◽  
pp. 597-607 ◽  
Author(s):  
Elliott W. Strauss
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Bile Salts ◽  
Intracellular Transport ◽  
Light And Electron Microscopy ◽  
Lipid Absorption ◽  
Apical Cytoplasm ◽  
Everted Sacs

Everted sacs of intestine from golden hamsters were incubated at 37°C for at least 1 hour in vitro with emulsified lipid after removal of both pancreatic lipase and bile salts. The fine structure of intestinal epithelium is well preserved under these conditions. Absorption of fat by the intestinal mucosa in vitro closely resembles lipid absorption in vivo, as observed by both light and electron microscopy. The physiological significance of these observations is discussed. Tubular elements of the agranular endoplasmic reticulum are often strikingly abundant in the apical cytoplasm of intestinal absorptive cells. These have a role in the intracellular transport of fat since they frequently contain droplets of lipid derived from the incubation medium. The rate of fat accumulation in the epithelium appears to be proportional to the concentration in the medium.

scholarly journals AN ANALYSIS OF COLLAGEN SECRETION BY ESTABLISHED MOUSE FIBROBLAST LINES

1964 ◽  
Vol 22 (1) ◽  
pp. 227-258 ◽  
Author(s):  
Burton Goldberg ◽  
Howard Green
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Mouse Fibroblast ◽  
In Vivo Studies ◽  
In Vitro Synthesis ◽  
Collagen Secretion ◽  
Golgi System ◽  
Alternative Theories

In vitro synthesis of collagen by established mouse fibroblast lines has been examined by electron microscopy. During rapid growth (log phase), when collagen could not be detected in the cultures, the cells lacked a well developed granular ergastoplasm and Golgi system. Upon cessation of growth (stationary phase), collagen accumulated in the cultures and the cells demonstrated highly developed granular and smooth ergastoplasm. Collagen appeared to be synthesized in the rough-surfaced endoplasmic reticulum and to be transported as a soluble protein to the cell surface by vesicular elements of the agranular ergastoplasm. Fusion of the limiting membranes of these vesicles with the cell membrane permitted the discharge of the soluble collagen into the extracellular space, where fibrils of two diameter distributions formed. The secretion of collagen is concluded to be of the merocrine type. Alternative theories of collagen secretion are discussed and the data for established lines compared with the results of other in vitro and in vivo studies of collagen fibrillogenesis.

scholarly journals LECITHIN SYNTHESIS, INTRACELLULAR TRANSPORT, AND SECRETION IN RAT LIVER

1969 ◽  
Vol 40 (2) ◽  
pp. 461-483 ◽  
Author(s):  
Olga Stein ◽  
Yechezkiel Stein
Keyword(s):  
Endoplasmic Reticulum ◽  
Liver Cell ◽  
Phosphatidyl Choline ◽  
Intracellular Transport ◽  
Phosphatidyl Ethanolamine ◽  
Specific Activity ◽  
Perfused Liver ◽  
Precursor Pool

Injection of choline-3H into choline-deficient rats resulted in an enhanced incorporation of the label into liver lecithin, as compared to the incorporation of label into liver lecithin of normal rats. The results obtained with the use of different lecithin precursors indicate that in the intact liver cell, both in vivo and in vitro, exchange of choline with phosphatidyl-choline is not significant. The synthesis and secretion of lecithins by the choline-deficient liver compare favorably with the liver of choline-supplemented rats, when both are presented with labeled choline or lysolecithin as lecithin precursors. Radioautography of the choline-deficient liver shows that 5 min after injection of choline-3H the newly synthesized lecithin is found in the endoplasmic reticulum (62%), mitochondria (13%), and at the "cell boundary" (20%). The ratio of the specific activity of microsomal and mitochondrial lecithin, labeled with choline, glycerol, or linoleate, was 1.53 at 5 min after injection, but the ratio of the specific activity of phosphatidyl ethanolamine (PE), labeled with ethanolamine, was 5.3. These results indicate that lecithin and PE are synthesized mainly in the endoplasmic reticulum, and are transferred into mitochondria at different rates. The site of a precursor pool of bile lecithin was studied in the intact rat and in the perfused liver. Following labeling with choline-3H, microsomal lecithin isolated from perfused liver had a specific activity lower than that of bile lecithin, but the specific activity of microsomal linoleyl lecithin was comparable to that of bile lecithin between 30 and 90 min of perfusion. It is proposed that the site of the bile lecithin pool is located in the endoplasmic reticulum and that the pool consists mostly of linoleyl lecithin.

scholarly journals FORMATION OF BONE TISSUE IN CULTURE FROM ISOLATED BONE CELLS

1974 ◽  
Vol 61 (2) ◽  
pp. 427-439 ◽  
Author(s):  
Itzhak Binderman ◽  
Dan Duksin ◽  
Arieh Harell ◽  
Ephraim Katzir (Katchalski) ◽  
Leo Sachs
Keyword(s):  
Electron Microscopy ◽  
Bone Tissue ◽  
Bone Cells ◽  
Light And Electron Microscopy ◽  
Bone Collagen ◽  
The Matrix ◽  
Three Stages ◽  
And Function

A system is described for the formation of bone tissue in culture from isolated rat bone cells. The isolated bone cells were obtained from embryonic rat calvarium and periosteum or from traumatized, lifted periosteum of young rats. The cells were cultured for a period of up to 8 wk, during which time the morphological, biochemical, and functional properties of the cultures were studied. Formation of bone tissue by these isolated bone cells was shown, in that the cells demonstrated osteoblastic morphology in light and electron microscopy, the collagen formed was similar to bone collagen, there was mineralization specific for bone, and the cells reacted to the hormone calcitonin by increased calcium ion uptake. Calcification of the fine structure of the cells and the matrix is described. Three stages in the calcification process were observed by electron microscopy. It is concluded that these bone cells growing in vitro are able to function in a way similar to such cells in vivo. This tissue culture system starting from isolated bone cells is therefore suitable for studies on the structure and function of bone.

scholarly journals ON THE SITE OF SULFATION IN COLONIC GOBLET CELLS

1964 ◽  
Vol 21 (3) ◽  
pp. 339-351 ◽  
Author(s):  
Nathan Lane ◽  
Lucien Caro ◽  
Luis R. Otero-Vilardebó ◽  
Gabriel C. Godman
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Goblet Cell ◽  
Sodium Sulfate ◽  
Goblet Cells ◽  
Rat Colon ◽  
Time Points

The location of bound S35 in the goblet cell of the rat colon at time points from 2 to 60 minutes after administration of S35 as sodium sulfate has been observed in vivo and in vitro by radioautographic techniques. Grains were first observed by electron microscopy over the stacked lamellae of the paranuclear part of the Golgi apparatus. The label was subsequently found associated with the supranuclear Golgi lamellae and was then seen associated with the smooth membranes limiting the mucin granules in the goblet. Finally, between ½ and 1 hour, the secreted mucus product in the crypts became radioactive. Neither mitochondria nor the endoplasmic reticulum was labeled. It is concluded that the Golgi apparatus is the organelle in which sulfation occurs.

scholarly journals In vitro fusion of Acanthamoeba phagolysosomes. I. Demonstration and quantitation of vacuole fusion in Acanthamoeba homogenates.

1976 ◽  
Vol 68 (2) ◽  
pp. 319-338 ◽  
Author(s):  
P J Oates ◽  
O Touster
Keyword(s):  
Electron Microscopy ◽  
Blood Cells ◽  
Fusion Reaction ◽  
Light And Electron Microscopy ◽  
Yeast Cells ◽  
Eosin Y ◽  
Vacuole Fusion ◽  
Lysosomal System

Fusion of phagolysosomes (PLs) has been demonstrated to occur in vitro. Two separate cell homogenates of the ameba Acanthamoeba sp. (Neff) were prepared, each rich in PLs labeled with distinctive particulate markers. Portions of each were incubated together in vitro and fusion occurred as evidenced by the appearance of PLs containing both types of markers. Fusion was confirmed by electron microscopy, including serial sectioning. The membranes of fused vacuoles excluded the dye eosin Y. Surviving cells in the homogenates were not responsible for the observed fusion. Fusion was obtained using either synthetic markers (polystyrene and polyvinyltoluene latex) or biological markers (autoclaved yeast cells and glutaraldehyde-fixed goat red blood cells), or a combination of both. The specificity of PL fusion in vivo appeared to be maintained in vitro. As determined by light and electron microscopy, the fusion reaction was dependent on time and temperature, and on the initial presence of membrane around both marker particles. A minimum of 10% of the vacuoles fused by 10 min of incubation at 30 degrees C, and no rupture of the vacuoles was detected during this time. After 10 min of incubation, vacuole rupture began and fusion ceased. At a constant initial vacuole concentration, the extent of PL fusion in vitro was quantitatively reproducible. This appears to be a promising system for further investigation of membrane fusion in the lysosomal system.

Germinal Vesicle Breakdown in the Mouse Oocyte

1972 ◽  
Vol 10 (2) ◽  
pp. 369-385 ◽  
Author(s):  
PATRICIA G. CALARCO ◽  
R. P. DONAHUE ◽  
D. SZOLLOSI
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Chromatin Condensation ◽  
Germinal Vesicle ◽  
Uniform Density ◽  
Multivesicular Bodies ◽  
Cortical Granules ◽  
Germinal Vesicle Breakdown

Germinal vesicle breakdown in mouse oocytes in vivo and in vitro has been examined by electron microscopy. In vitro oocytes were studied immediately after release from follicles and at various times (0.5-11 h) in culture. Approximately 30 min after oocyte release, chromatin condensation begins along the convoluted nuclear envelope (NE). Chromatin granules are common in all condensing chromosomes. Heterochromatin, visible from early condensation until chromosomes are of uniform density, often is observed near the kinetochores. The nucleolus breaks down after peripheral incorporation of separate nucleolus-associated bodies composed of 25-nm diameter fibrils. These bodies are later found free in the cytoplasm. As chromosome condensation progresses, the NE becomes highly convoluted, then discontinuous, finally forming NE doublets. Spindle formation begins with the appearance near the NE of small medium-dense areas from which microtubules emanate. No centrioles are present. Dark granules and mitochondria move centrally in the oocyte and surround the spindle. Peripheral cortical granules and large aggregations of multivesicular bodies are present at all stages. The Golgi apparatus is not well developed. Very little rough endoplasmic reticulum is present, although free ribosomal clusters are common. There are no significant ultrastructural differences between eggs maturing in vivo and in vitro.

scholarly journals An Endoplasmic Reticulum Protein, p180, Is Highly Expressed in Human Cytomegalovirus-Permissive Cells and Interacts with the Tegument Protein Encoded by UL48

2002 ◽  
Vol 76 (5) ◽  
pp. 2350-2362 ◽  
Author(s):  
K. Ogawa-Goto ◽  
S. Irie ◽  
A. Omori ◽  
Y. Miura ◽  
H. Katano ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Human Cytomegalovirus ◽  
Intracellular Transport ◽  
Late Phase ◽  
Terminal Region ◽  
Electron Microscopic ◽  
Replication Process ◽  
Overlay Assay

ABSTRACT We have used a virus overlay assay to detect cellular proteins associated with human cytomegalovirus (HCMV) particles. The radiolabeled HCMV particles specifically bound to two host proteins with molecular sizes of 150 and 180 kDa. By a micro-amino-acid sequencing technique, the 180-kDa protein was identified as a human homologue of the ES130/p180 ribosome receptor (p180), which is an integral endoplasmic reticulum (ER) membrane protein possessing a very unique tandem repeat domain at its N-terminal region. The virus overlay assay using truncated p180 polypeptides revealed that HCMV binding to human p180 occurred through the N-terminal region. In HCMV-permissive cells the high level of expression of the human p180 protein was clearly observed regardless of cell type. Furthermore, we showed that p180 binds to the UL48 gene product, which is one of the predominant tegument proteins of HCMV and which is considered to be tightly associated with the capsid. The interaction between the two proteins was assumed to be specific and was observed both in vitro and in vivo. During the late phase of infection, the unique relocation of human p180 was observed, that is, to the juxtanuclear region, which appeared to be in the vicinity of the area where naked virions were frequently observed in an electron-microscopic study. Thus our data suggest that p180 interacts with the HCMV tegument, at least through pUL48, during the HCMV replication process. We discuss the possible role of the interaction between p180 and pUL48 in the intracellular transport of HCMV virions.

A quick, simple method for purifying Leishmania mexicana amastigotes in large numbers

Parasitology ◽  
1981 ◽  
Vol 82 (3) ◽  
pp. 345-355 ◽  
Author(s):  
D. T. Hart ◽  
K. Vickerman ◽  
G. H. Coombs
Keyword(s):  
Electron Microscopy ◽  
Buoyant Density ◽  
Light And Electron Microscopy ◽  
Host Cells ◽  
Leishmania Mexicana ◽  
Cell Debris ◽  
Simple Method ◽  
Large Numbers

SUMMARYA rapid method for the bulk isolation of purified Leishmania mexicana mexicana amastigotes from parasite-induced lesions in experimentally infected mice is described. The procedure includes purification steps based on differences in net cell charge, lysis susceptibility and buoyant density between parasite and host cells. Yields of up to 2 × 1010 untransformed amastigotes with minimal contamination with host cells and cell debris can be obtained. At least 90 % of the purified amastigotes are viable as judged by light and electron microscopy, the staining of their lysosomes with acridine orange, their ability to transform to promastigotes and their infectivity to macrophages in vivo and in vitro.

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