scholarly journals Electron Microscopic Observations on the Penetration of Bdellovibrio bacteriovorus into Gram-negative Bacterial Hosts1

1968 ◽  
Vol 96 (4) ◽  
pp. 1366-1381 ◽  
Author(s):  
Jeffrey C. Burnham ◽  
T. Hashimoto ◽  
S. F. Conti
Keyword(s):  
Electron Microscopic ◽  
Bdellovibrio Bacteriovorus ◽  
Gram Negative

Ultrastructural studies of Chlamydia psittaci 6BC variant strains. I. Ultrastructure of the surface layers of egg-passaged 6BC strain

1973 ◽  
Vol 19 (8) ◽  
pp. 887-894
Author(s):  
Linda Poffenroth ◽  
J. W. Costerton ◽  
Nonna Kordová ◽  
John C. Wilt
Keyword(s):  
Chick Embryo ◽  
Microscopic Examination ◽  
Electron Microscopic Examination ◽  
Chlamydia Psittaci ◽  
Gram Negative Bacteria ◽  
Surface Layers ◽  
Electron Microscopic ◽  
Gram Negative ◽  
Ultrastructural Studies ◽  
First Time

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.

scholarly journals Growth Control of Adherent-Invasive Escherichia coli (AIEC) by the Predator Bacteria Bdellovibrio bacteriovorus: A New Therapeutic Approach for Crohn’s Disease Patients

2019 ◽  
Vol 8 (1) ◽  
pp. 17 ◽  
Author(s):  
Giulia Bonfiglio ◽  
Bruna Neroni ◽  
Giulia Radocchia ◽  
Arianna Pompilio ◽  
Francesco Mura ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Growth Control ◽  
Coli Strain ◽  
Bdellovibrio Bacteriovorus ◽  
Gram Negative ◽  
Intestinal Dysbiosis ◽  
Predatory Bacteria ◽  
Human Ecosystems

In Crohn’s disease (CD) patients, intestinal dysbiosis with an overgrowth of Proteobacteria, mainly Escherichia coli, has been reported. A new pathotype of E. coli, the adherent-invasive Escherichia coli strain (AIEC), has been isolated from the mucosae of CD patients. AIEC strains play an important role in CD pathogenesis, increasing intestinal mucosa damage and inflammation. Several studies have been undertaken to find possible strategies/treatments aimed at AIEC strain reduction/elimination from CD patients’ intestinal mucosae. To date, a truly effective strategy against AIEC overgrowth is not yet available, and as such, further investigations are warranted. Bdellovibrio bacteriovorus is a predator bacterium which lives by invading Gram-negative bacteria, and is usually present both in natural and human ecosystems. The aim of this study was to evaluate a novel possible strategy to treat CD patients’ mucosae when colonized by AIEC strains, based on the utilization of the Gram-negative predatory bacteria, B. bacteriovorus. The overall results indicate that B. bacteriovorus is able to interfere with important steps in the dynamics of pathogenicity of AIEC strains by its predatory activity. We indicate, for the first time, the possibility of counteracting AIEC strain overgrowth by exploiting what naturally occurs in microbial ecosystems (i.e., predation).

Fine structure of selected species of the genus Thiobacillus as revealed by chemical fixation and freeze-etching

1974 ◽  
Vol 20 (10) ◽  
pp. 1347-1351 ◽  
Author(s):  
Stanley C. Holt ◽  
J. M. Shively ◽  
J. W. Greenawalt
Keyword(s):  
Inclusion Bodies ◽  
Convex Surface ◽  
Cell Envelope ◽  
Electron Microscopic Examination ◽  
Gram Negative Bacteria ◽  
Chemical Fixation ◽  
Electron Microscopic ◽  
Gram Negative ◽  
Freeze Etching ◽  
Outer Plasma Membrane

An electron-microscopic examination of selected species of the genus Thiobacillus was undertaken using the techniques of chemical fixation and freeze-etching. The architecture of the cells was typical of gram-negative bacteria. The multilayered cell envelope was revealed as a complex of smooth, rough, and particle-studded membranes. The particles which covered the outer plasma membrane (convex surface) appeared to contain a differentiated region which might permit a channeling between the exterior and interior of the cell. Inclusion bodies, including paracrystalline arrays, carboxysomes, and granules were present.

scholarly journals Antibacterial Properties of Some Cyclic Organobismuth(III) Compounds

2005 ◽  
Vol 49 (7) ◽  
pp. 2729-2734 ◽  
Author(s):  
Toshiaki Kotani ◽  
Daisuke Nagai ◽  
Kensuke Asahi ◽  
Hitomi Suzuki ◽  
Fumiaki Yamao ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Properties ◽  
Cell Number ◽  
Viable Cell Number ◽  
Electron Microscopic ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Ring Compounds ◽  
Medical Disorders

ABSTRACT Bismuth compounds are known for their low levels of toxicity in mammals, and various types of bismuth salts have been used to treat medical disorders. As part of our program to probe this aspect of bismuth chemistry, cyclic organobismuth compounds 1 to 8 bearing a nitrogen or sulfur atom as an additional ring member have been synthesized, and their antimicrobial activities against five standard strains of gram-negative and gram-positive bacteria were assessed. The eight-membered-ring compounds, compounds 1 to 3, exhibited MICs of less than 0.5 μg/ml against Staphylococcus aureus and were more active than the six-membered ones, compounds 5 to 8 (MICs, 4.0 to 16 μg/ml). The gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, and Enterococcus faecalis) were more susceptible to both types of ring compounds than the gram-negative ones (Escherichia coli and Pseudomonas aeruginosa). Treatment with polymyxin B nonapeptide increased the susceptibility of E. coli to cyclic organobismuth compounds, indicating the low permeability of the outer membrane of gram-negative bacteria to the compounds. Compound 1 also had activity against methicillin-resistant S. aureus, which had an MIC for 90% of the hospital stock strains of 1.25 μg/ml. The killing curves for S. aureus treated with compound 1 or 3 revealed a static effect at a low dose (2× the MIC). However, when S. aureus was treated with 10× the MIC of compound 1 or 3, there was an approximately 3-log reduction in the viable cell number after 48 h of treatment. Electron microscopic inspection demonstrated a considerable increase in the size of S. aureus and the proportion of cells undergoing cell division after treatment with compound 1 at 0.5× the MIC.

The caceum of the Koala, Phascolarctos cinereus: Light, scanning and transmission electron microscopic observations on its epithelium and flora

1978 ◽  
Vol 26 (2) ◽  
pp. 249 ◽  
Author(s):  
RA McKenzie
Keyword(s):  
Columnar Epithelium ◽  
Electron Microscopic ◽  
Gram Positive ◽  
Phascolarctos Cinereus ◽  
Gram Negative ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
Different Types

The pseudostratified columnar epithelium of the koala caecum is surmounted on its luminal border by a tall palisade fringe of bacteria of different types including Gram-positive and Gram-negative bacilli, cocci and actinomycete-like organisms. Ultrastructure of the epithelium indicates that it absorbs water and nutrients from the caecal lumen, and secretes mucus to lubricate the passage of ingesta.

scholarly journals A CYTOCHEMICAL LOCALIZATION OF REDUCTIVE SITES IN A GRAM-NEGATIVE BACTERIUM

1964 ◽  
Vol 20 (3) ◽  
pp. 377-387 ◽  
Author(s):  
Woutera van Iterson ◽  
W. Leene
Keyword(s):  
Plasma Membrane ◽  
Electron Scattering ◽  
Gram Negative Bacteria ◽  
Proteus Vulgaris ◽  
Electron Microscopic ◽  
Cytochemical Localization ◽  
Gram Negative ◽  
Living State ◽  
Granular Matrix ◽  
Reducing Activity

In order to obtain information on the exact location of the respiratory enzyme chain in Gram-negative bacteria, an electron microscopic study was made of the sites of reducing activity of cells that had, in the living state, incorporated tellurite. In the test object Proteus vulgaris, the reduced tellurite was found to be deposited in bodies contiguous with the plasma membrane but different in structure from those described in the Gram-positive Bacillus subtilis (2). In fact, the bodies proved to consist of a conglomerate of elements which contained the strongly electron-scattering reduced tellurite and a delicately granular "matrix." A limiting membrane was not observed around these complexes. In serial sections details of the complexes are illustrated. Reduced tellurite was not deposited in the plasma membrane to any important degree. Since no other sites of deposition of the reduced product were revealed, it is assumed that the complexes represent the mitochondrial equivalents in the investigated organism. In addition, the bodies might function as the basal granules of the flagella.

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