Fine Structure and Radiation Resistance in Acinetobacter: Studies on a Resistant Strain

1968 ◽  
Vol 3 (2) ◽  
pp. 273-294
Author(s):  
MARGARET J. THORNLEY ◽  
AUDREY M. GLAUERT
Keyword(s):  
Cell Wall ◽  
Fine Structure ◽  
Radiation Resistance ◽  
Cell Walls ◽  
Proteolytic Enzymes ◽  
Gram Negative Bacteria ◽  
Intact Cells ◽  
Thin Sections ◽  
Gram Negative ◽  
Isolated Cell

An electron-microscope study of thin sections and negatively stained preparations of intact cells and isolated cell walls of a bacterium which is moderately resistant to ionizing radiation, Acinetobacter strain 199A, showed that it is similar to other Gram-negative bacteria except for its mode of division and for the fine structure of some of the surface layers. During division the cells form a fairly thick septum similar to those observed in Gram-positive bacteria. An examination of the appearance and chemical composition of isolated cell walls before and after treatment with enzymes, detergents and lipid solvents revealed that three layers, each with a characteristic fine structure, are present in the cell wall: (1) an outer membrane with an array of peg-like subunits; (2) a layer of wrinkled material which is digested by proteolytic enzymes; and (3) a smooth, rigid layer, which contains the mucopeptide components of the cell wall. These observations are compared with the results of other workers for various Gram-negative bacteria. From comparisons with the structure of more radiation-sensitive strains of Acinetobacter, it appears that layer (2) may be associated with the radiation resistance of the organism.

LYSOZYME SENSITIVITY OF THE CELL WALL OF PSEUDO-MONAS AERUGINOSA: FURTHER EVIDENCE FOR THE ROLE OF THE NON-PEPTIDOGLYCAN COMPONENTS IN CELL WALL RIGIDITY

1966 ◽  
Vol 12 (1) ◽  
pp. 105-108 ◽  
Author(s):  
K. Jane Carson ◽  
R. G. Eagon
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cell Wall ◽  
Electron Micrographs ◽  
Cell Walls ◽  
Gram Negative Bacteria ◽  
Normal Cells ◽  
Thin Sections ◽  
Gram Negative ◽  
Cell Wall Rigidity

Electron micrographs of thin sections of normal cells of Pseudomonas aeruginosa showed the cell walls to be convoluted and to be composed of two distinct layers. Electron micrographs of thin sections of lysozyme-treated cells of P. aeruginosa showed (a) that the cell walls lost much of their convoluted nature; (b) that the layers of the cell walls became diffuse and less distinct; and (c) that the cell walls became separated from the protoplasts over extensive cellular areas. These results suggest that the peptidoglycan component of the unaltered cell walls of P. aeruginosa is sensitive to lysozyme. Furthermore, it appears that the peptidoglycan component is not solely responsible for the rigidity of the cell walls of Gram-negative bacteria.

scholarly journals THE FINE STRUCTURE OF STALKED BACTERIA BELONGING TO THE FAMILY CAULOBACTERACEAE

1964 ◽  
Vol 23 (3) ◽  
pp. 587-607 ◽  
Author(s):  
Jeanne L. Stove Poindexter ◽  
Germaine Cohen-Bazire
Keyword(s):  
Cell Wall ◽  
Fine Structure ◽  
Cell Membrane ◽  
Multilayered Structure ◽  
Gram Negative Bacteria ◽  
Thin Sections ◽  
Gram Negative ◽  
Cytoplasmic Region ◽  
The Core ◽  
The Family

The fine structure of a series of stalked bacteria belonging to the genera Caulobacter and Asticcacaulis has been examined in thin sections. The cell wall has the multilayered structure typical of many Gram-negative bacteria, and continues without interruption throughout the length of the stalk. The core of the stalk, continuous with the cytoplasmic region of the cell, is enclosed in an extension of the cell membrane, and contains a system of internal membranes: it is devoid of ribosomes and nucleoplasm. A membranous organelle occupies the juncture of stalk and cell, separating the ribosomal region from the core of the stalk. Typical mesosomes also occur in the cell, being particularly frequent at the plane of division. The secreted holdfast is located at the tip of the stalk in Caulobacter, and at the pole of the cell adjacent to the stalk in Asticcacaulis.

scholarly journals FINE STRUCTURE OF THE GRAM-NEGATIVE BACTERIUM ACETOBACTER SUBOXYDANS

1964 ◽  
Vol 20 (2) ◽  
pp. 217-233 ◽  
Author(s):  
G. W. Claus ◽  
L. E. Roth
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Cell Walls ◽  
Negative Staining ◽  
Homogeneous Layer ◽  
Physical Treatment ◽  
Thin Sections ◽  
Gram Negative ◽  
Acetobacter Suboxydans ◽  
Negative Cell

The morphological features of the cell wall, plasma membrane, protoplasmic constituents, and flagella of Acetobacter suboxydans (ATCC 621) were studied by thin sectioning and negative staining. Thin sections of the cell wall demonstrate an outer membrane and an inner, more homogeneous layer. These observations are consistent with those of isolated, gram-negative cell-wall ghosts and the chemical analyses of gram-negative cell walls. Certain functional attributes of the cell-wall inner layer and the structural comparisons of gram-negative and gram-positive cell walls are considered. The plasma membrane is similar in appearance to the membrane of the cell wall and is occasionally found to be folded into the cytoplasm. Certain features of the protoplasm are described and discussed, including the diffuse states of the chromatinic material that appear to be correlated with the length of the cell and a polar differentiation in the area of expected flagellar attachment. Although the flagella appear hollow in thin sections, negative staining of isolated flagella does not substantiate this finding. Severe physical treatment occasionally produces a localized penetration into the central region of the flagellum, the diameter of which is much smaller then that expected from sections. A possible explanation of this apparent discrepancy is discussed.

scholarly journals Ionic Relations of Cells of Ohara Australis I. Ion Exchange in the Cell Wall

1959 ◽  
Vol 12 (4) ◽  
pp. 395 ◽  
Author(s):  
J Dainty ◽  
AB Hope
Keyword(s):  
Cell Wall ◽  
Ion Exchange ◽  
Free Space ◽  
Cell Walls ◽  
Plant Cells ◽  
External Solution ◽  
Exchangeable Cations ◽  
Intact Cells ◽  
Donnan Free Space ◽  
Isolated Cell

Measurements of ion exchange were made between isolated cell walls of Ohara australis and an external solution. Comparison between intact cells and cell walls showed that nearly all the easily exchangeable cations are located in the cell wall. The wall is hown to consist of "water free space" (W.F.S.) and "Donnan free space" (D.F.S.); the concentration of in diffusible anions in the D.F.S. is about O� 6 equivjl. This finding is contrary to past suggestions that the D.F.S. is in the cytoplasm of plant cells.

The effects of phospholipid depletion on the cleavage pattern of the cell walls of frozen Gram-negative bacteria

1973 ◽  
Vol 19 (8) ◽  
pp. 1056-1057 ◽  
Author(s):  
A. Forge ◽  
J. W. Costerton
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Cytoplasmic Membrane ◽  
Gram Negative Bacteria ◽  
Cleavage Pattern ◽  
Gram Negative ◽  
Whole Cells ◽  
The Cross ◽  
Double Track ◽  
Chloroform Methanol

Extraction of whole cells of the marine pseudomonad (B-16) with chloroform–methanol causes the disappearance of the cleavage planes, and the cross-sectioned profile of both the cytoplasmic membrane and the double-track layer of the cell wall.

scholarly journals Fine Structure and Radiation Resistance in Acinetobacter: A Comparison Of A Range Of Strains

1971 ◽  
Vol 8 (1) ◽  
pp. 19-41
Author(s):  
AUDREY M. GLAUERT ◽  
MARGARET J. THORNLEY
Keyword(s):  
Cell Wall ◽  
Fine Structure ◽  
Outer Membrane ◽  
Radiation Resistance ◽  
Resistant Strain ◽  
The Other ◽  
Dense Layer ◽  
Gram Negative ◽  
Comparative Results ◽  
Resistance To Ionizing Radiation

Nine strains of the Gram-negative bacterium, Acinetobacter, showed a wide variation in resistance to ionizing radiation; all gave sigmoid survival curves, with D10 values for the exponential portion ranging from 70 to 460 J kg-1 (7-46 krd). The fine structure of these strains was studied by electron microscopy. Results for a resistant strain were described earlier and the present paper gives comparative results for the other 8 strains. The mode of division varied, 5 strains dividing predominantly by constriction of all the layers of the cell wall, while the other 4strains showed ingrowth of thick septa. These 4 included the 3 most resistant strains and I strain of intermediate resistance. The arrangement of surface layers was the same as that usually found in Gram-negative bacteria. In 1 strain an extra layer was visible outside the outer membrane; this layer does not appear to influence radiation resistance since it is lacking in another strain of similar resistance. The layer of wrinkled material, previously observed in the resistant strain between, the outer membrane and the intermediate dense layer of the cell wall, in negatively stained preparations of isolated cell walls, was seen in 5 other strains of intermediate and high resistance, while in 3 sensitive strains finely granular material appeared to occupy a corresponding position in the cell wall. These observations suggest that morphological features, such as the wrinkled layer of the cell wall, and possibly the mode of cell division, may influence the radiation resistance of Acinetobacter strains, but their function is not yet known.

Electron Microscopic Observations on the Effects of Polymixin B Sulfate to Cell Walls of Chlamydia Organisms

1972 ◽  
Vol 30 ◽  
pp. 326-327
Author(s):  
Akira Matsumoto
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Present Report ◽  
Bactericidal Effect ◽  
Chlamydia Psittaci ◽  
Gram Negative Bacteria ◽  
Electron Microscopic ◽  
Cell Content ◽  
Gram Negative ◽  
Reticulate Body

Cell walls of the both types of bodies, mature elementary body(EB) and developmental reticulate body(RB) of Chlamydia psittaci appear the triple layered membrane in thin section. However, in the preparations shadowcast or stained negatively EB cell wall shows hexagonally arrayed structure composed of subunits, 180A in diameter on the inside surface, whereas RB cell wall does not have this structure. Chemical analysis demonstrated that EB cell wall contained a similar amino acid composition with the cell walls of gram-negative bacteria, such as E.coli. The bactericidal effect of polymixin group against gram-negative bacilli is understood that the drug affects to the cell wall and destroys its osmotic regulation. Electron microscopy on the effects of the drug against the gram-negative bacteria revealed the formation of numerous number of projections on the cell wall surface and leakage of cell content through the projections. The present report is concerned with further studies on the fine structure of EB cell walls based on the observation on their response to polymixin B sulfate.

Elektronenoptische und chemische Untersuchungen an Zellwänden der Blaualge Phormidium uncinatum

1962 ◽  
Vol 17 (4) ◽  
pp. 262-268 ◽  
Author(s):  
H. Frank ◽  
Marcelle Lefort ◽  
H. H. Martin
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Quantitative Chemical Analysis ◽  
Cell Wall Component ◽  
Thin Sections ◽  
Blue Green Algae ◽  
Phormidium Uncinatum ◽  
Localized Defects ◽  
Isolated Cell ◽  
Supporting Membrane

Quantitative chemical analysis of isolated cell walls of Phormidium uncinatum demonstrated the presence of a mucopolymer component resembling in composition that found in the cell walls of gramnegative bacteria. Electronmicroscopical investigations showed that each cell of a filament of Phormidium is lined with a mucopolymer supporting membrane, which is responsible for the rigidity of the cell wall and which can be digested by lysozyme.Growing filaments of Phormidium, exposed to penicillin, produce well recognizable localized defects in the mucopolymer layer of their cell walls and in the corresponding layers of septa still growing. These defects appear to indicate regions of growth.Electronmicroscopical examination of thin sections of intact filaments extend and confirm the morphological observations on isolated cell walls.The demonstration in blue-green algae of a mucopolymer cell wall component closely resembling that previously found in cell walls of bacteria provides further evidence for a taxonomic relationship between the two classes of organisms.

Metal fixation by bacterial cell walls

1985 ◽  
Vol 22 (12) ◽  
pp. 1893-1898 ◽  
Author(s):  
T. J. Beveridge ◽  
W. S. Fyfe
Keyword(s):  
Cell Wall ◽  
Metal Binding ◽  
Bacterial Cell ◽  
Cell Walls ◽  
Nucleation And Growth ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Element Transport ◽  
Cell Wall Polymers

All biomass contains a significant quantity of metallic constituents, and mineralization in living and dead biodebris may contribute to element transport from the hydrosphere into sediments. The anionic cell walls of bacteria are remarkable in their ability to fix metals and provide sites for nucleation and growth of minerals. Results presented show the types of cell wall polymers that are responsible for metal binding in walls of Gram-positive and Gram-negative bacteria.

Ultrastructural changes in the conidia of Penicillium notatum during germination

1973 ◽  
Vol 19 (7) ◽  
pp. 797-801 ◽  
Author(s):  
J. F. Martin ◽  
F. Uruburu ◽  
J. R. Villanueva
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Ultrastructural Changes ◽  
Dense Layer ◽  
Penicillium Notatum ◽  
Thin Sections ◽  
Resting Spores ◽  
Different Types ◽  
Germ Tubes ◽  
Isolated Cell

To study the changes in the cell wall of Penicillium notatum during germination, thin sections of resting, swollen, and germinating spores, and mycelium were compared with thin sections of the isolated cell walls. In the cell wall of resting spores four distinct layers were found. The outermost layer of the cell wall of resting spores was released during swelling and the two inner layers were extended to form the cell wall of the germ tube. The cell wall of young germ tubes had only two layers but a new electron-dense layer was formed later on the outside. Mycelial cell walls which appeared thinner than those of conidia showed three distinct layers. Large mitochondria that divide during germination were present in both resting and swollen spores. Two different types of vacuoles were found, both of which decreased in size and in number during germination. Endoplasmic reticulum was almost absent in resting spores but increased substantially during swelling.

Sign in / Sign up

Export Citation Format

Share Document