Mitochondrial Extensions Associated with Microtubules in Outgrowing Processes from Chick Spinal Cord in Vitro

1969 ◽  
Vol 4 (3) ◽  
pp. 729-737
Author(s):  
FELICITY GRAINGER ◽  
D. W. JAMES

Electron-microscopic examination of processes growing out from chick spinal cord cultivated in vitro raises the possibility that mitochondria may be continuous with a system of membrane-bound profiles ramifying within the cytoplasm. These profiles are distinctive in appearance, and appear to establish a particular spatial relationship with microtubules. In this, dense material extends from the profiles to constitute a meshwork within whose interstices tubules lie. The suggestion is made that these appearances may reflect the utilization of the products of mitochondrial activity for transport by microtubules.

Author(s):  
Frank R. Galey

Histological studies have demonstrated an hexachlorophene induced change of the cerebral white matter in rats (Kimbrough). The following report is an ultrastructural description of the changes as seen in monkeys, with an attempt to explain the molecular mechanism by which the changes develop.A dose of 3 mg of hexachlorophene per kg was administered subcutaneously to four juvenile (3-4 yrs) monkeys (Macaca mulatta) twice daily for 3 months. At the end of the experiment four treated monkeys and two stock control monkeys were sacrificed under anesthesia. The head region was perfused with 2.5% glutaraldehyde in a modified Tyrode's solution and tissues were sampled from spinal cord, superior colliculus, thalamus-callosum, cerebellum and optic nerve, and prepared for electron microscopic examination.Light microscopic examination revealed the development of cystic spaces in the thalamus-callosum samples from all of the treated animals. Optic nerve and spinal cord samples also demonstrated cystic spaces, but not as extensively as in thalamus-callosum.


1971 ◽  
Vol 134 (5) ◽  
pp. 1155-1169 ◽  
Author(s):  
Fred G. Gudat ◽  
T. N. Harris ◽  
Susanna Harris ◽  
Klaus Hummeler

Mice injected with sheep RBC and then, 4 days later with thymidine-3H, were sacrificed on the day of thymidine-3H injection or 1 or 2 days later. Hemolytic antibody plaque preparations were made of cells from the draining lymph nodes by a thin-plating procedure permitting collection of isolated PFC for electron microscopic examination and radioautography. Of cells obtained on the day of thymidine-3H injections, 65% of the labeled PFC were in the lymphocytic category, in comparison with 13% found previously in the entire population of such cells. The remaining 35% were plasmablasts in early stages of differentiation. Cells obtained 1 day after the thymidine-3H injections showed a shift to a majority of labeled cells in the plasmacytic category. Also, the plasmablasts were substantially more differentiated than those of the previous day, and some mature plasma cells were now seen. The labeled PFC obtained on day 2 gave no indication of further differentiation. Cells of rabbit lymph nodes labeled in vitro with thymidine-3H showed a range of labeled PFC. The majority were in the plasmacytic category, including some mature plasma cells. The data from the experiments with in vivo labeling suggest a direct differentiation from antibody-synthesizing lymphocytes to plasma cells. Further, the in vivo experiments indicated that differentiation from nascent lymphocyte to plasma cell could be essentially completed within 1 day.


Author(s):  
K. S. McCarty ◽  
R. F. Weave ◽  
L. Kemper ◽  
F. S. Vogel

During the prodromal stages of sporulation in the Basidiomycete, Agaricus bisporus, mitochondria accumulate in the basidial cells, zygotes, in the gill tissues prior to entry of these mitochondria, together with two haploid nuclei and cytoplasmic ribosomes, into the exospores. The mitochondria contain prominent loci of DNA [Fig. 1]. A modified Kleinschmidt spread technique1 has been used to evaluate the DNA strands from purified whole mitochondria released by osmotic shock, mitochondrial DNA purified on CsCl gradients [density = 1.698 gms/cc], and DNA purified on ethidium bromide CsCl gradients. The DNA appeared as linear strands up to 25 u in length and circular forms 2.2-5.2 u in circumference. In specimens prepared by osmotic shock, many strands of DNA are apparently attached to membrane fragments [Fig. 2]. When mitochondria were ruptured in hypotonic sucrose and then fixed in glutaraldehyde, the ribosomes were released for electron microscopic examination.


Author(s):  
Veronika Burmeister ◽  
N. Ludvig ◽  
P.C. Jobe

Electron microscopic immunocytochemistry provides an important tool to determine the ultrastructural distribution of various molecules in both normal and pathologic tissues. However, the specific immunostaining may be obscured by artifactual immunoreaction product, misleading the investigator. Previous observations show that shortening the incubation period with the primary antibody from the generally used 12-24 hours to 1 hour substantially reduces the artifactual immunostaining. We now extend this finding by the demonstration of artifact-free ultrastructural localization of the Ca2/calmodulindependent cyclic nucleotide phosphodiesterase (CaM-dependent PDE) immunoreactivity in brain.Anesthetized rats were perfused transcardially with phosphate-buffered saline followed by a fixative containing paraformaldehyde (4%) and glutaraldehyde (0.25%) in PBS. The brains were removed, and 40μm sections were cut with a vibratome. The sections were processed for immunocytochemistry as described by Ludvig et al. Both non-immune rabbit serum and specific CaM-dependent PDE antibodies were used. In both experiments incubations were at one hour and overnight. The immunostained sections were processed for electron microscopic examination.


1973 ◽  
Vol 19 (8) ◽  
pp. 887-894
Author(s):  
Linda Poffenroth ◽  
J. W. Costerton ◽  
Nonna Kordová ◽  
John C. Wilt

Electron microscopic examination of a semipurified Chlamydia psittaci 6BC strain attenuated in chick embryo yolk sac revealed for the first time two morphologically distinct small elementary bodies which differ both in the ultrastructure of their surface layers and in their buoyant densities in sucrose gradients. Also, the morphology of the surface layers of the larger reticulate forms in cell-free systems is described for the first time. Many points of difference between the surface envelopes and internal structure of chlamydial particles and those of Gram-negative bacteria are discussed.


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