Electron-Microscopic Studies on the Activity of the Reactions of Acid Phosphatase in Rats with Transplantable Guérin Epithelioma

Histochemical procedures show a concentrated zone of phosphomonoesterase activity in the substantia gelatinosa of mouse spinal cord which represents at least two enzymic activities. At pH 7,5'-nucleotidase activity is observed in both somata and neuropil, while at pH 5 the reaction is evident only in somata. An acid phosphatase of unknown specificity is seen in somata only and exhibits optimal activity near pH 5. No comparable enzymic reactions are observed in cat spinal cord sections. Electron microscopic studies demonstrate separate cytologic distributions of the two enzymic activities in substantia gelatinosa. With nucleotides, the reaction is confined to boundaries of processes within the neuropil and to nuclei at pH 7. At pH 5 using an acid phosphatase substrate, β-glycerol phosphate, slight reactions were noted within nerve fibers. Use of β-glycerol phosphate near pH 7 demonstrates both types of activity simultaneously, the boundary reactions typical of the nucleotidase and the reactions within axons and dendrites characteristic of the phosphatase.

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Electron microscopic studies of the rickettsia Coxiella burnetii: entry, lysosomal response, and fate of rickettsial DNA in L-cells

Canadian Journal of Microbiology ◽

10.1139/m71-025 ◽

1971 ◽

Vol 17 (2) ◽

pp. 143-150 ◽

Cited By ~ 28

Author(s):

Paul R. Burton ◽

Nonna Kordová ◽

David Paretsky

Keyword(s):

Electron Microscope ◽

Acid Phosphatase ◽

Host Cell ◽

Coxiella Burnetii ◽

Cell Nucleus ◽

Tritiated Thymidine ◽

Electron Microscopic ◽

Dynamic Interactions ◽

L Cells ◽

Microscopic Studies

The rickettsial agent Coxiella burneti was studied in cultured mouse L cells by use of the electron microscope. Rickettsiae gain entry to the host cell in an apparently passive manner through phagocytic activity by L cells. The L cells show a lysosomal response to the presence of rickettsiae, as determined by cytochemical tests for acid phosphatase and 5′-nucleotidase. Further, examination of C. burneti within lysosomes suggests that rickettsiae can be degraded by the host cell. Autoradiographic analyses using tritiated thymidine show that rickettsial DNA is largely restricted to the dense nucleoid region, and when such labeled rickettsiae are used to inoculate L cells, most of the label becomes localized in the host cell nucleus. The above information is discussed in terms of dynamic interactions between C. burneti and infected L cells.

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The Accumulation of Lipofuscin in the Epithelium of the Midgut of the Aging Housefly, Musca Domestica.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100117108 ◽

1975 ◽

Vol 33 ◽

pp. 696-697

Author(s):

S.L. Duncan ◽

R.S. Sohal ◽

V.F. Allison

Keyword(s):

Acid Phosphatase ◽

Musca Domestica ◽

Fat Body ◽

Osmic Acid ◽

Electron Microscopic ◽

Age Related ◽

Transmission Electron ◽

Cellular Autophagy ◽

Somatic Tissues ◽

Microscopic Studies

Since somatic tissues in adult dipteran insects are entirely composed of post-mitotic cells, they are especially suited to studies concerned with structural alterations associated with aging. Previous reports mainly concerned with laboratory mammals and human tissues indicate an age-related accumulation of lipofuscin. Electron microscopic studies on aging houseflies have reported age-associated changes which include an increase in cellular autophagy and lipofuscin accumulation in nervous tissue, fat body and heart. The present study is concerned with electron microscopic and histochemical examination of the epithelium of the midgut of the housefly, Musca domestica. Special attention is given to the formation of lipofuscin and to the localization of acid phosphatase activity in aging animals.Tissue was acquired from the midgut of houseflies of known ages, fixed in gluteraldehyde and refixed in osmic acid. Samples were prepared by the method of Gomori for acid phosphatase localization. The preparations were embedded in Maraglas and studied with the Hitachi HUllB-2 transmission electron microscope.

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Electron microscopic studies on ultrathin frozen sections of lactating mouse mammary gland

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081097 ◽

1978 ◽

Vol 36 (2) ◽

pp. 46-47

Author(s):

Jan Zarzycki ◽

Joseph Szroeder

Keyword(s):

Mammary Gland ◽

Protein Denaturation ◽

Chemical Constituents ◽

Freeze Substitution ◽

Electron Microscopic Examination ◽

Mouse Mammary Gland ◽

Electron Microscopic ◽

Preparation Methods ◽

Microscopic Studies ◽

Ultrathin Frozen Sections

The mammary gland ultrastructure in various functional states is the object of our investigations. The material prepared for electron microscopic examination by the conventional chemical methods has several limitations, the most important are the protein denaturation processes and the loss of large amounts of chemical constituents from the cells. In relevance to this,one can't be sure about a degree the observed images are adequate to the realy ultrastructure of a living cell. To avoid the disadvantages of the chemical preparation methods,some autors worked out alternative physical methods based on tissue freezing / freeze-drying, freeze-substitution, freeze-eatching techniqs/; actually the technique of cryoultraraicrotomy,i,e.cutting ultrathin sections from deep frozen specimens is assented as a complete alternative method. According to the limitations of the routine plastic embbeding methods we were interested to analize the mammary gland ultrastructure during lactation by the cryoultramicrotomy method.

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Early Development of Drug-Induced Hepatic Necrosis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100066942 ◽

1971 ◽

Vol 29 ◽

pp. 576-577

Author(s):

F. G. Zaki ◽

E. Detzi ◽

C. H. Keysser

Keyword(s):

Early Development ◽

Hepatic Necrosis ◽

Screening Tests ◽

Dense Matrix ◽

Sprague Dawley ◽

Electron Microscopic ◽

Drug Induced ◽

Hepatocellular Damage ◽

Sprague Dawley Rats ◽

Microscopic Studies

This study represents the first in a series of investigations carried out to elucidate the mechanism(s) of early hepatocellular damage induced by drugs and other related compounds. During screening tests of CNS-active compounds in rats, it has been found that daily oral administration of one of these compounds at a dose level of 40 mg. per kg. of body weight induced diffuse massive hepatic necrosis within 7 weeks in Charles River Sprague Dawley rats of both sexes. Partial hepatectomy enhanced the development of this peculiar type of necrosis (3 weeks instead of 7) while treatment with phenobarbital prior to the administration of the drug delayed the appearance of necrosis but did not reduce its severity.Electron microscopic studies revealed that early development of this liver injury (2 days after the administration of the drug) appeared in the form of small dark osmiophilic vesicles located around the bile canaliculi of all hepatocytes (Fig. 1). These structures differed from the regular microbodies or the pericanalicular multivesicular bodies. They first appeared regularly rounded with electron dense matrix bound with a single membrane. After one week on the drug, these vesicles appeared vacuolated and resembled autophagosomes which soon developed whorls of concentric lamellae or cisterns characteristic of lysosomes (Fig. 2). These lysosomes were found, later on, scattered all over the hepatocytes.

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