Peroxidase Localization in Hartmanella Trophozoites

Author(s):  
George E. Childs ◽  
Joseph H. Miller

Biochemical and differential centrifugation studies have demonstrated that the oxidative enzymes of Acanthamoeba sp. are localized in mitochondria and peroxisomes (microbodies). Although hartmanellid amoebae have been the subject of several electron microscopic studies, peroxisomes have not been described from these organisms or other protozoa. Cytochemical tests employing diaminobenzidine-tetra HCl (DAB) and hydrogen peroxide were used for the ultrastructural localization of peroxidases of trophozoites of Hartmanella sp. (A-l, Culbertson), a pathogenic strain grown in axenic cultures of trypticase soy broth.

1986 ◽  
Vol 34 (12) ◽  
pp. 1687-1690 ◽  
Author(s):  
W E Müller ◽  
B Diehl-Seifert ◽  
C Sobel ◽  
A Bechtold ◽  
Z Kljajić ◽  
...  

The secondary metabolite avarol, a potent cytostatic and antibacterial sesquiterpenoid hydroquinone, is present in large amounts only in the sponge Dysidea avara (2.7 g avarol/1 kg of fresh material). The present study was designed to determine the storage site of this compound within the organism. Light and transmission electron microscopic studies revealed that avarol is probably stored only in spherular cells. The compound is compartmented in intracellular cytoplasmic vesicles in a paracrystalline form, and therefore can have no inhibitory effect on the sponge cells. Quantitative analysis utilizing high-pressure liquid chromatography revealed that avarol is present at a concentration of 3.2 micrograms/10(6) spherular cells. It appears that avarol is released from the cells into the extracellular space in a merocrine manner. We suggest that it is involved in regulating the bacteria with which the sponge is symbiotically associated.


1968 ◽  
Vol 170 (1020) ◽  
pp. 319-329 ◽  

By differential centrifugation of extracts of pigmented Rhodopseudomonas spheroides a number of constituents, phospholipid and lipid ornithine, and enzymes, zinc protoporphyrin chelatase, succinic dehydrogenase and S-adenosylmethionine-magnesium protoporphyrin methyltransferase, have been found to be associated both with chromatophores and with non-pigmented particulate material. These components are present in both types of material at about the same level. In extracts of non-pigmented organisms the particulate material contains some of the above components, but others are only present in low amounts. The subcellular structures present in the particulate material—ribosomes, cell wall and cytoplasmic membrane—have only been partially separated but, by comparing the distribution of the components listed above with those of known components of ribosomes and cell wall, it is probable that they are associated with cytoplasmic membrane. These studies suggest that the cytoplasmic membrane, apart from lacking the photosynthetic pigments, has a composition similar to that of chromatophores. The data are consistent with the conclusion drawn from electron microscopic studies that chromatophores are derived by invagination of the cytoplasmic membrane.


1986 ◽  
Vol 34 (2) ◽  
pp. 159-165 ◽  
Author(s):  
S Angermüller ◽  
H D Fahimi

Ultrastructural localization of uricase (urate: oxygen oxidoreductase, E.C.1.7.3.3.) in rat liver parenchymal cells has been studied with the cerium technique. The cerous ions react with H2O2 generated by the activity of the enzyme in the presence of urate, forming the electron-dense reaction product of cerous perhydroxide. Tissue fixation is carried out by perfusion for 5 min with a low concentration (0.25%) of glutaraldehyde. Since in a biochemical assay it was found that the activity of uricase determined in Trismaleate buffer is substantially weaker than in the Pipes buffer, the classical medium of Briggs et al. (6) was modified, and the latter buffer was substituted for the Trismaleate. Vibratome sectons are incubated at 37 degrees C for 60 min in 0.1 M Pipes buffer, pH 7.8, containing 3 mM cerium chloride and 0.1 mM sodium urate. Under these conditions, the reaction product is localized in the crystalline cores of hepatic peroxisomes. The intensity of the staining is dependent on the concentration of the substrate and the incubation time. In control preparations incubated without urate or with 2,6,8-trichloropurine, a specific inhibitor of uricase, staining is almost completely abolished. In sections incubated with 5 mM cerium and 0.1 mM sodium urate, fine granules with a distribution corresponding to peroxisomes are also visible at the light microscopic level. This latter observation is invaluable for correlative light and electron microscopic studies.


1981 ◽  
Vol 29 (6) ◽  
pp. 687-692 ◽  
Author(s):  
G M Gilad ◽  
V H Gilad

The present work describes a new method for cytochemical localization of enzymes using ornithine decarboxylase (ODC) as an example. The method is based on the preservation of the characteristic-specific and irreversible binding of the inhibitor alpha-difluoromethylornithine (alpha-DFMO) following its conjugation to "label" molecules. The inhibitor has been conjugated to the fluorescent molecule rhodamine-B-isothiocyanate, and its localization in tissue sections was detected directly by fluorescence cytochemistry. Alternatively, alpha-DFMO has been conjugated to biotin and its cytochemical localization determined indirectly following its binding with avidin conjugated to horseradish peroxidase (HRP) and visualization of the HRP reaction product. Both labeled inhibitor molecules were successfully localized cytochemically within specific cells of the developing rat cerebellum and rat liver following thioacetamide injection where ODC activity is greatly enhanced. This novel technique should be of general application 1) in other tissues, 2) for other enzymes, and 3) in electron microscopic studies for ultrastructural localization of the enzyme.


1971 ◽  
Vol 19 (6) ◽  
pp. 361-368 ◽  
Author(s):  
W. D. KUHLMANN ◽  
S. AVRAMEAS

A new staining procedure for glucose oxidase at both the light and the electron microscopic level has been developed. The procedure was equally effective for the detection of galactose oxidase. It appears that the method can be applied to all oxidoreductases which catalyze the production of hydrogen peroxide. Aspergillus niger glucose oxidase and Dacytlium dendroides galactose oxidase were used to immunize rabbits and mice in order to trace the distribution of specific antibodies in the immunocytes of the popliteal lymph nodes.


1991 ◽  
Vol 39 (12) ◽  
pp. 1725-1728 ◽  
Author(s):  
G J van Dam ◽  
B J Bogitsh ◽  
J A Fransen ◽  
D Kornelis ◽  
R J van Zeyl ◽  
...  

We report the application of a fluorescein isothiocyanate (FITC)-anti-FITC method to localize antigens at the ultrastructural level. In the systems studied, the anti-FITC-based detection method displays high specificity and sensitivity. These observations, combined with ease of production and with availability of FITC-protein conjugates, suggest that the FITC-anti-FITC method is a good alternative to presently used methods and is widely applicable to immunochemical and immunocytochemical procedures. The same preparation and protocol can be used for light and electron microscopic studies, thereby reducing possible artifacts introduced if different procedures are used. In the present study, two systems were used to test the method. One system used an FITC-labeled monoclonal antibody (MAb) to schistosome circulating cathodic antigen. In this system, the label was detected in the gut of adult Schistosoma mansoni by an anti-FITC MAb conjugated to 10-nm gold particles. The second system used human IgM antibodies pooled from patients infected with Schistosoma mansoni. In this system detection was accomplished using an anti-human IgM-FITC conjugate followed by the anti-FITC-Au antibody conjugate.


Author(s):  
Jan Zarzycki ◽  
Joseph Szroeder

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.


Author(s):  
F. G. Zaki ◽  
E. Detzi ◽  
C. H. Keysser

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.


Author(s):  
T. Mullin ◽  
G. Yee ◽  
M. Aheam ◽  
J. Trujillo

There have been numerous reports in the current literature suggesting that hematopoietic precursor cells in some human chronic myelocytic leukemias (CML) undergo lymphoblastic transformation at the time of the acute blast crisis (BC) stage. The primary evidence offered in support of this transformation theory--lymphoblastic appearing morphology, increased terminal deoxynucleotidyl transferase (TdT) activity, and chemotherapeutic sensitivity to vincristine and prednisone--has been indirect, however, since these features may occur in nonlymphoid cells. More direct support for the Pre-B lineage of these cells has recently been provided by immunofluorescent light microscopic studies demonstrating the presence of intracytoplasmic immunoglobulin M (IgM) in these CML-BC cells.


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