Comparative Systems Analysis of Opportunistic Gram-Negative Pathogens

Acinetobacter sp. HO-1-N, a gram-negative hydrocarbon oxidizing bacterium previously designated Micrococcus cerificans, has been shown to sequester the hydrocarbon into intracytoplasmic pools as a result of growth on this substrate. In hydrocarbon grown cells, an intracytoplasmic membrane system was also observed along with a doubling of cellular phospholipids (Z). However, using conventional dehydration and embedding procedures in preparing thin sectioned material, the hydrocarbon is extracted from the cells. This may lead to structural distortion, consequently, the freeze-etch technique was applied to preserve the integrity of the cell.

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Bacterial-Mucosal Cell Junctional Complexes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100050731 ◽

1974 ◽

Vol 32 ◽

pp. 144-145

Author(s):

Roger C. Wagner

Keyword(s):

Intestinal Wall ◽

Rat Colon ◽

Mucosal Cell ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Mucosal Cells ◽

Mucosal Lining ◽

Degenerative Alterations ◽

Junctional Complexes ◽

Intestinal Mucosal Cells

Bacteria exhibit the ability to adhere to the apical surfaces of intestinal mucosal cells. These attachments either precede invasion of the intestinal wall by the bacteria with accompanying inflammation and degeneration of the mucosa or represent permanent anchoring sites where the bacteria never totally penetrate the mucosal cells.Endemic gram negative bacteria were found attached to the surface of mucosal cells lining the walls of crypts in the rat colon. The bacteria did not intrude deeper than 0.5 urn into the mucosal cells and no degenerative alterations were detectable in the mucosal lining.

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Microanatomy of the Periplasm of Bacillus Licheniformis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100065365 ◽

1971 ◽

Vol 29 ◽

pp. 262-263

Author(s):

B.K. Ghosh

Keyword(s):

Cell Wall ◽

Plasma Membrane ◽

Bacillus Licheniformis ◽

External Environment ◽

Permeability Barrier ◽

Periplasmic Space ◽

Modified Technique ◽

Gram Positive ◽

Gram Negative ◽

Gram Positive Bacteria

Periplasm of bacteria is the space outside the permeability barrier of plasma membrane but enclosed by the cell wall. The contents of this special milieu exterior could be regulated by the plasma membrane from the internal, and by the cell wall from the external environment of the cell. Unlike the gram-negative organism, the presence of this space in gram-positive bacteria is still controversial because it cannot be clearly demonstrated. We have shown the importance of some periplasmic bodies in the secretion of penicillinase from Bacillus licheniformis.In negatively stained specimens prepared by a modified technique (Figs. 1 and 2), periplasmic space (PS) contained two kinds of structures: (i) fibrils (F, 100 Å) running perpendicular to the cell wall from the protoplast and (ii) an array of vesicles of various sizes (V), which seem to have evaginated from the protoplast.

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