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

1971 ◽  
Vol 17 (2) ◽  
pp. 143-150 ◽  
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.

scholarly journals Host cell adhesion to Schistosoma mansoni larvae in the peritoneal cavity of naive mice: histological and scanning electron microscopic studies

1993 ◽  
Vol 35 (1) ◽  
pp. 17-22 ◽  
Author(s):  
Alan Lane de Melo ◽  
Conceição Ribeiro da Silva Machado ◽  
Leógenes Horácio Pereira
Keyword(s):  
Cell Adhesion ◽  
Schistosoma Mansoni ◽  
Host Cell ◽  
Peritoneal Cavity ◽  
Mononuclear Cells ◽  
Close Contact ◽  
Histological Study ◽  
Electron Microscopic ◽  
Microscopic Studies ◽  
Scanning Electron

Cercariae of Schistosoma mansoni inoculated into the peritoneal cavity of naive mice induced host cell adhesion to their surface, but after 90 minutes the number of adherent cells sharply decreased. The cell detachment is progressive and simultaneous to the cercaria-schistosomule transformation. The histological study showed mainly neutrophils in close contact with the larvae. Mononuclear cells and some eosinophils were occasionally seen surrounding the adherent neutrophils. The scanning electron microscopy showed cells displaying twisted microvilli and several microplicae contacting or spreading over the larval surface, and larvae completely surrounded by clusters of cells. These results suggest that the neutrophils recognize molecules on the cercarial surface which induce their spreading

scholarly journals An Electron Microscope Study of Snow Crystal Nuclei

1953 ◽  
Vol 2 (13) ◽  
pp. 176-180
Author(s):  
Ukichiro Nakaya
Keyword(s):  
Electron Microscope ◽  
Electron Microscope Study ◽  
Condensation Nuclei ◽  
Electron Microscopic ◽  
Carbon Particles ◽  
Snow Crystal ◽  
Microscopic Studies ◽  
Snow Crystals ◽  
Micro Organisms ◽  
Collodion Film

AbstractSnow crystals were received on the collodion film of the holder of an electron microscope, and made to sublimate without melting. These specimens were investigated under an electron microscope. One solid nucleus was always observed in the central portion of a snow crystal. These centre nuclei were of sizes between 0.5 and 8μ. Most of them were presumed to be kaolin, clay or carbon particles; some were considered to be micro-organisms. In the other parts of snow crystals numerous smaller nuclei were observed, whose dimensions were of the order of those of condensation nuclei. These condensation nuclei were found to be of two kinds, the larger ones most frequently having a diameter of about 0.15μ, the smaller ones of about 0.05μ. A new theory was proposed from the data of the electron microscopic studies and those of the conditions of formation of snow crystals. In this theory it is proposed that minute water droplets of 1μor so play an important rôls in the process of snow crystal growth.

Electron microscopic observations of the envelopes of isolated algal packets of Azolla

1991 ◽  
Vol 69 (7) ◽  
pp. 1418-1419 ◽  
Author(s):  
Eiji Uheda ◽  
Shunji Kitoh
Keyword(s):  
Electron Microscope ◽  
Nitric Acid ◽  
Sodium Hydroxide ◽  
Key Words ◽  
Layer Structure ◽  
Sodium Dodecylsulfate ◽  
Electron Microscopic ◽  
Microscopic Studies ◽  
20 Nm

The envelopes of isolated algal packets from cyanobiont-containing and cyanobiont-free Azolla were examined with the electron microscope. Both types of envelope were 10–20 nm thick and composed of three layers. The three-layer structure was also observed when algal packets were treated with cellulase, pectinase, lipase, protease, sodium hydroxide, nitric acid, or sodium dodecylsulfate. Thus, the envelopes do not appear to be membrane-like in nature and the presence and ultrastructure of the envelopes are not affected by cyanobiont filaments. Key words: algal packet, cyanobiont-free Azolla, Azolla, electron microscopic studies, envelope.

Electron Microscopic Studies of Fillers in Rubber. III. Effect of Milling on the Dispersion of Fillers

1956 ◽  
Vol 29 (3) ◽  
pp. 1003-1010 ◽  
Author(s):  
Eiji Suito ◽  
Masafumi Arakawa ◽  
Hiroshi Hasegawa ◽  
Yonemasa Furusawa
Keyword(s):  
Electron Microscope ◽  
Marked Effect ◽  
The State ◽  
Replica Method ◽  
Interesting Problem ◽  
Electron Microscopic ◽  
Vulcanized Rubber ◽  
Microscopic Studies ◽  
Filler Particles ◽  
The Relationship

Abstract In the study of types of fillers which have a marked effect on the properties of rubber, information as to how the filler particles are dispersed in rubber is a prerequisite. The authors have already reported on the state of dispersion of various fillers in vulcanized rubber, observed under an electron microscope by the replica method. How the dispersion of these fillers affects the properties of rubber is an interesting problem. Since, in the earlier work, filler particles were observed to orient themselves in certain directions, in this report the relationship between the state of dispersion observed under an electron microscope of filler particles in rubber milled in different ways and the resulting characteristics of the mixtures were examined.

Structure and host–actinomycete interactions in developing root nodules of Comptonia peregrina

1978 ◽  
Vol 56 (5) ◽  
pp. 502-531 ◽  
Author(s):  
William Newcomb ◽  
R. L. Peterson ◽  
Dale Callaham ◽  
John G. Torrey
Keyword(s):  
Host Cell ◽  
Root Nodules ◽  
Host Cells ◽  
Electron Microscopic ◽  
Cortical Cells ◽  
Host Cytoplasm ◽  
Transmission Electron ◽  
Microscopic Studies ◽  
Host Plasma Membrane ◽  
Soil Actinomycete

Correlated fluorescence, bright-field, transmission electron, and scanning electron microscopic studies were made on developing root nodules of Comptonia peregrina (L.) Coult. (Myricaceae) produced by a soil actinomycete which invades the root and establishes a symbiosis leading to fixation of atmospheric dinitrogen. After entering the host via a root hair infection, the hyphae of the endophyte perforate root cortical cells by local degradation of host cell walls and penetration of the host cytoplasm. The intracellular hyphae are always surrounded by host plasma membrane and a thick polysaccharide material termed the capsule. (For convenience, term intracellular refers to the endophyte being inside a Comptonia cell as distinguished from being intercellular, i.e.. between host cells, even though the former is actually extracellular as the endophyte is separated from the host cytoplasm by the host plasmalemma.) Numerous profiles of vesiculate rough endoplasmic reticulum (RER) occur near the growing hyphae. Although the capsule shows a positive Thiery reaction indicating its polysaccharide nature, the fibrillar contents of the RER do not, leaving uncertain whether the capsule results from polymers derived from the RER. Amyloplasts of the cortical cells lose their starch deposits during hyphal proliferation. The hyphae branch extensively in specific layers of the cortex, penetrating much of the host cytoplasm. At this stage, hyphal ends become swollen and form septate club-shaped vesicles within the periphery of the host cells. Lipid-like inclusions and Thiery-positive particles, possibly glycogen, are observed in the hyphae at this time. Associated with hyphal development is an increase in average host cell volume, although nuclear volume appears to remain constant. Concomitant with vesicle maturation, the mitochondrial population increases sharply, suggesting a possible relationship to vesicle function. The intimate interactions between host and endophyte during development of the symbiotic relationship are emphasized throughout.

Electron microscope study on the glial filaments of astrocytes in the rat brain

1978 ◽  
Vol 36 (2) ◽  
pp. 618-619
Author(s):  
S. Mori ◽  
K. Furukawa ◽  
H. Abe
Keyword(s):  
Body Weight ◽  
Electron Microscope ◽  
Glial Cells ◽  
Microscope Study ◽  
Phosphate Buffer ◽  
Electron Microscope Study ◽  
Gold Chloride ◽  
Electron Microscopic ◽  
New Knowledge ◽  
Microscopic Studies

With the electron microscope, it was demonstrated that the glial filaments existed in astrocytes and could be impregnated by Cajal's gold chloride sublimate solution. By this conspicuous structure of glial filaments, thus, the astrocytes have long been differentiated from other glial cells from the classical light microscopic studies till the recent electron microscopic observations. Further investigations could add the new knowledge on this important component of glial cells in this laboratory that the actin- like filaments might be contained among the glial filaments. It will be shown in this report that glial filaments of astrocytes are consisted of the heterogenous groups of filaments, and some of them can bind with the heavy meromyosins (HMM).Normal rats (about 120 g body weight) were anesthetized with Nembutal and fixed by perfusion through the heart for 30 minutes with the fixative. This fluid was consisted of 3 % glutaraldehyde, 2 % paraformaldehyde, 4 % sucrose and 0. 5 mM CaCl2 in 0. 1 M phosphate buffer at PH 7. 4.

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