Effect of E. coli L-form cytoplasmic membranes on the phagocytosis of Yersinia pseudotuberculosis PYV (+) cells: Transmission electron microscopy

1997 ◽  
Vol 56 (1-3) ◽  
pp. 119
Author(s):  
I Janchev
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Yersinia Pseudotuberculosis ◽  
E Coli ◽  
Transmission Electron ◽  
Cytoplasmic Membranes

An Ultrastructural Study of Chronic Pyelonephritis in Macaca Arctoides

1976 ◽  
Vol 34 ◽  
pp. 310-311
Author(s):  
T.W. Smith ◽  
J.A. Roberts ◽  
B.J. Martin
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ultrastructural Study ◽  
Effective Means ◽  
Chronic Pyelonephritis ◽  
Macaca Arctoides ◽  
Left Ureter ◽  
E Coli ◽  
Transmission Electron ◽  
Sizeable Number

Chronic pyelonephritis is one of the most common diseases of the kidney and accounts for a sizeable number of cases of renal insufficiency in man, however its pathogenesis requires further elucidation. Transmission electron microscopy may serve as a uniquely effective means of observing details of the nature of this disease. The present paper describes preliminary results of an ultrastructural study of chronic pyelonephritis in Macaca arctoides (stumptail monkey).The infection was induced in these experiments in a retrograde fashion by means of a unilateral catheterization of the left ureter whereby an innoculum of 10 cc of broth containing approximately 2 billion E. coli per cc and radio-opaque dye were injected under pressure (mimicing vesico-ureteric reflux).

scholarly journals Antimicrobial Properties of a Chitosan Dextran-Based Hydrogel for Surgical Use

2011 ◽  
Vol 56 (1) ◽  
pp. 280-287 ◽  
Author(s):  
Manal A. Aziz ◽  
Jaydee D. Cabral ◽  
Heather J. L. Brooks ◽  
Stephen C. Moratti ◽  
Lyall R. Hanton
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Bacterial Species ◽  
Antimicrobial Properties ◽  
Sinus Surgery ◽  
Peptide Bonds ◽  
Content Type ◽  
E Coli ◽  
Transmission Electron

ABSTRACTA chitosan dextran-based (CD) hydrogel, developed for use in endoscopic sinus surgery, was tested for antimicrobial activityin vitroagainst a range of pathogenic microorganisms. The microdilution technique was used to determine minimum inhibitory, minimum bactericidal, and minimum fungicidal concentrations. In addition, the time-kill efficacy of CD hydrogel was determined for two bacterial species. Scanning and transmission electron microscopy were carried out to elucidate the antimicrobial mechanism of this compound. CD hydrogel was found to be effective againstStaphylococcus aureus,Streptococcus pyogenes,Escherichia coli, andClostridium perfringensat its surgical concentration of 50,000 mg/liter. Minimum bactericidal concentrations ranged from 2,000 to 50,000 mg/liter. Dextran aldehyde (DA) was found to be the antimicrobial component of the CD hydrogel with MBC ranging from 2,000 to 32,000 mg/liter.S. aureusappeared to be killed at a slightly faster rate thanE. coli. Candida albicansandPseudomonas aeruginosawere more resistant to CD hydrogel and DA. Scanning and transmission electron microscopy ofE. coliandS. aureusincubated with CD hydrogel and DA alone revealed morphological damage, disrupted cell walls, and loss of cytosolic contents, compatible with the proposed mode of action involving binding to cell wall proteins and disruption of peptide bonds. Motility and chemotaxis tests showedE. colito be inhibited when incubated with DA. The antibacterial activity of CD hydrogel may make it a useful postsurgical aid at other body sites, especially where there is a risk of Gram-positive infections.

Determination of Bacterial Cell Dry Mass by Transmission Electron Microscopy and Densitometric Image Analysis

1998 ◽  
Vol 64 (2) ◽  
pp. 688-694 ◽  
Author(s):  
M. Loferer-Krößbacher ◽  
J. Klima ◽  
R. Psenner
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Image Analysis ◽  
Bacterial Biomass ◽  
Dry Weight ◽  
Dry Mass ◽  
Bacterial Cells ◽  
E Coli ◽  
Transmission Electron ◽  
Bacterial Assemblages

ABSTRACT We applied transmission electron microscopy and densitometric image analysis to measure the cell volume (V) and dry weight (DW) of single bacterial cells. The system was applied to measure the DW ofEscherichia coli DSM 613 at different growth phases and of natural bacterial assemblages of two lakes, Piburger See and Gossenköllesee. We found a functional allometric relationship between DW (in femtograms) and V (in cubic micrometers) of bacteria (DW = 435 · V 0.86); i.e., smaller bacteria had a higher ratio of DW to V than larger cells. The measured DW of E. coli cells ranged from 83 to 1,172 fg, and V ranged from 0.1 to 3.5 μm3(n = 678). Bacterial cells from Piburger See and Gossenköllesee (n = 465) had DWs from 3 fg (V = 0.003 μm3) to 1,177 fg (V = 3.5 μm3). Between 40 and 50% of the cells had a DW of less than 20 fg. By assuming that carbon comprises 50% of the DW, the ratio of carbon content to Vof individual cells varied from 466 fg of C μm−3 forVs of 0.001 to 0.01 μm3 to 397 fg of C μm−3 (0.01 to 0.1 μm3) and 288 fg of C μm−3 (0.1 to 1 μm3). Exponentially growing and stationary cells of E. coli DSM 613 showed conversion factors of 254 fg of C μm−3 (0.1 to 1 μm3) and 211 fg of C μm−3 (1 to 4 μm3), respectively. Our data suggest that bacterial biomass in aquatic environments is higher and more variable than previously assumed from volume-based measurements.

Screening of Condensed Tannins from Canadian Prairie Forages for Anti–Escherichia coli O157:H7 with an Emphasis on Purple Prairie Clover (Dalea purpurea Vent)†

2013 ◽  
Vol 76 (4) ◽  
pp. 560-567 ◽  
Author(s):  
Y. WANG ◽  
L. JIN ◽  
K. H. OMINSKI ◽  
M. HE ◽  
Z. XU ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Transmission Electron Microscopy ◽  
Condensed Tannins ◽  
Brown Seaweed ◽  
Coli Strain ◽  
Escherichia Coli O157 ◽  
Canadian Prairie ◽  
E Coli ◽  
Transmission Electron

Tannins from forages grown (n = 10) on the Canadian prairie, as well as from Quebracho, Rhus semialata, and brown seaweed (Ascophyllum nodosum), were screened for anti–Escherichia coli O157:H7 activity against E. coli O157:H7 strain 3081 at a concentration of 400 μg/ml for each tannin type, except for brown seaweed, which was at 50 μg/ml. Growth of the bacteria was assessed by measuring the optical density at 600 nm over 24 h. Tannin from seaweed at a concentration of 50 μg/ml inhibited growth of strain 3081. Among the terrestrial forages, only condensed tannins (CT) from purple prairie clover (Dalea purpurea Vent; PPC) increased (P < 0.05) the lag time and reduced (P < 0.05) the growth rate of E. coli O157:H7. The anti–E. coli O157:H7 activity of PPC CT was further assessed by culturing E. coli strain ATCC 25922 and eight strains of E. coli O157:H7 with PPC CT at 0, 25, 50, 100, or 200 μg/ml. Selected strains were enumerated after 0, 6, and 24 h of incubation, and fatty acid composition was determined after 24 h of incubation. E. coli strain 25922 was cultured with 0, 50, or 200 μg of CT per ml and harvested during the exponential growth phase for examination by transmission electron microscopy. Increasing CT concentration linearly increased (P < 0.001) the lag times of seven strains and linearly reduced (P < 0.001) the growth rates of eight E. coli O157:H7 strains. Proportions of unsaturated fatty acids in the total fatty acids were decreased (P < 0.01) by CT at 50 μg/ml. Transmission electron microscopy showed that CT disrupted the outer membrane structure. Anti–E. coli O157:H7 activity of PPC CT at levels of up to 200 μg/ml was bacteriostatic rather than bactericidal, and the mechanism of anti–E. coli activity may involve alteration in the fatty acid composition and disruption of the outer membrane of the cell.

scholarly journals Comparison in Gnotobiotic Pigs of Lesions Caused by Verotoxigenic and Non-verotoxigenic Escherichia coli

1988 ◽  
Vol 25 (3) ◽  
pp. 205-210 ◽  
Author(s):  
G. A. Hall ◽  
N. Chanter ◽  
A. P. Bland
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Transmission Electron Microscopy ◽  
Intestinal Tissue ◽  
E Coli ◽  
Histological Sections ◽  
Transmission Electron ◽  
Colony Forming Units ◽  
Gnotobiotic Pigs

To compare the pathogenesis of calf and rabbit strains of E. coli. gnotobiotic pigs were infected with 1010 colony forming units (cfu) of verotoxigenic strain RDEC-1 or S102-9, or a non-verotoxigenic E. coli (X114/83). Pigs were killed 4 days later, and intestinal tissue was fixed and examined by light, scanning, and transmission electron microscopy. Strains S102-9 and RDEC-1 caused diarrhea, attached to enterocytes, and effaced microvilli, confirming that the calf and rabbit strains possessed similar mechanisms of pathogenicity. Non-verotoxigenic strain X114/83 did not cause diarrhea, but in 5/5 piglets it was detected in histological sections adherent to enterocyte surfaces. Exfoliated enterocytes were seen in 4/5. Bacteria attached to enterocytes by “cups” and “pedestals,” with effacement of microvilli, were seen by electron microscopy in 1/5 piglets. It was concluded that strain S102-9 appears to be an animal equivalent of human enterohemorrhagic E. coli. that verotoxin is not essential in the pathogenesis of attaching and effacing lesions, and that the lesions induced by S102-9 are more severe in gnotobiotic pigs than in gnotobiotic or conventional calves.

scholarly journals Structure-Function Relationship of Antibacterial Synthetic Peptides Homologous to a Helical Surface Region on Human Lactoferrin against Escherichia coli Serotype O111

1998 ◽  
Vol 66 (6) ◽  
pp. 2434-2440 ◽  
Author(s):  
Daniel S. Chapple ◽  
David J. Mason ◽  
Christopher L. Joannou ◽  
Edward W. Odell ◽  
Vanya Gant ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Transmission Electron Microscopy ◽  
Flow Cytometry ◽  
Antibacterial Activity ◽  
Synthetic Peptides ◽  
Membrane Integrity ◽  
E Coli ◽  
Transmission Electron ◽  
Helical Region

ABSTRACT Lactoferricin includes an 11-amino-acid amphipathic alpha-helical region which is exhibited on the outer surface of the amino-terminal lobe of lactoferrin. Synthetic peptides homologous to this region exhibited potent antibacterial activity against a selected range of both gram-negative and gram-positive bacteria. An analog synthesized with methionine substituted for proline at position 26, which is predicted to disrupt the helical region, abolished antibacterial activity against Escherichia coli and considerably reduced antibacterial activity against Staphylococcus aureus and anAcinetobacter strain. The mode of action of human lactoferrin peptide (HLP) 2 against E. coli serotype O111 (NCTC 8007) was established by using flow cytometry, surface plasmon resonance, and transmission electron microscopy. Flow cytometry was used to monitor membrane potential, membrane integrity, and metabolic processes by using the fluorescent probes bis-1,3-(dibutylbarbituric acid)-trimethine oxonol, propidium iodide, and carbonyl cyanide m-chlorophenylhydrazone, respectively. HLP 2 was found to act at the cell membrane, causing complete loss of membrane potential after 10 min and of membrane integrity within 30 min, with irreversible damage to the cell as shown by rapid loss of viability. The number of particles, measured by light scatter on the flow cytometer, dropped significantly, showing that bacterial lysis resulted. The peptide was shown to bind toE. coli O111 lipopolysaccharide by using surface plasmon resonance. Transmission electron microscopy revealed bacterial distortion, with the outer membrane becoming detached from the inner cytoplasmic membrane. We conclude that HLP 2 causes membrane disruption of the outer membrane, resulting in lysis, and that structural considerations are important for antibacterial activity.

Effect of Slightly Acidic Electrolyzed Water for Inactivating Escherichia coli O157:H7 and Staphylococcus aureus Analyzed by Transmission Electron Microscopy

2010 ◽  
Vol 73 (12) ◽  
pp. 2211-2216 ◽  
Author(s):  
SONGJIAN NAN ◽  
YONGYU LI ◽  
BAOMING LI ◽  
CHAOYUAN WANG ◽  
XIAODONG CUI ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Transmission Electron Microscopy ◽  
Treatment Time ◽  
Escherichia Coli O157 ◽  
Electrolyzed Water ◽  
E Coli ◽  
Transmission Electron ◽  
And Staphylococcus Aureus

The use of different available chlorine concentrations (ACCs) of slightly acidic electrolyzed water (SAEW; 0.5 to 30 mg/liter), different treatment times, and different temperatures for inactivating Escherichia coli O157:H7 and Staphylococcus aureus was evaluated. The morphology of both pathogens also was analyzed with transmission electron microscopy. A 3-min treatment with SAEW (pH 6.0 to 6.5) at ACCs of 2 mg/liter for E. coli O157:H7 and 8 mg/liter for S. aureus resulted in 100% inactivation of two cultures (7.92- to 8.75-log reduction) at 25°C. The bactericidal activity of SAEW was independent of the treatment time and temperature at a higher ACC (P > 0.05). E. coli O157:H7 was much more sensitive than S. aureus to SAEW. The morphological damage to E. coli O157:H7 cells by SAEW was significantly greater than that to S. aureus cells. At an ACC as high as 30 mg/liter, E. coli O157:H7 cells were damaged, but S. aureus cells retained their structure and no cell wall damage or shrinkage was observed. SAEW with a near neutral pH may be a promising disinfectant for inactivation of foodborne pathogens.

Transmission Electron Microscopy Study of Enterohemorrhagic Escherichia coli O157:H7 in Apple Tissue

2005 ◽  
Vol 68 (2) ◽  
pp. 216-224 ◽  
Author(s):  
MARLENE E. JANES ◽  
K. S. KIM ◽  
M. G. JOHNSON
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Transmission Electron Microscopy ◽  
Plasma Membranes ◽  
Single Cells ◽  
Enterohemorrhagic Escherichia Coli ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Transmission Electron ◽  
Apple Tissue

We investigated the ability of enterohemorrhagic Escherichia coli O157:H7 to spread in wounded apple tissue by transmission electron microscopy. Red Delicious apples were wounded with an artist knife (7 mm depth) and either inoculated with 10 μl per wound of decimally diluted E. coli O157:H7 or submerged into E. coli O157:H7 suspended in sterile distilled water and then stored at 37°C for 24 h. Transmission electron microscopy showed E. coli O157:H7 formed bacterial aggregates near the apple cell walls, and single cells were in close proximity to the apple cell wall surfaces and to plasma membranes. E. coli O157:H7 presence caused degradation of plasma membranes and release of the cytoplasm contents of the apple cortical cells into the central vacuole. Apple tissue turgor pressure tests showed that the apple cells infected with E. coli O157:H7 isolates were more likely to rupture than the control noninoculated apple cells. E. coli O157:H7 cells grown in apple tissue showed the formation of granules and vesicles within the bacterial cytoplasma and separation of the plasma membranes. Our study shows that E. coli O157:H7 can grow and survive in the apple tissue environment by causing degradation of the apple cellular components.

scholarly journals Assessing the Expression of Enterotoxigenic Escherichia coli-specific Surface Antigens in Recombinant Strains by Transmission Electron Microscopy and Immunolabeling

2006 ◽  
Vol 54 (4) ◽  
pp. 473-477 ◽  
Author(s):  
Stefan Lüdi ◽  
Joachim Frey ◽  
Didier Favre ◽  
Michael H. Stoffel
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Transmission Electron Microscopy ◽  
Surface Antigens ◽  
Negative Staining ◽  
Enterotoxigenic Escherichia Coli ◽  
Wild Type ◽  
E Coli ◽  
Recombinant Strains ◽  
Transmission Electron

Infections with enterotoxigenic Escherichia coli (ETEC) are a major cause of travelers' diarrhea worldwide. Colonization of the small intestine mucosa is dependent on specific colonization factor antigens (CFA) and coli surface (CS) antigens. CFA/1, CS3, and CS6 are the most prevalent fimbrial antigens found in clinical isolates. The goal of our study was to visualize the morphology of CS3 and CS6 fimbriae in wild-type and recombinant E. coli strains by means of transmission electron microscopy in conjunction with negative staining and immunolabeling. Corresponding ETEC genes were cloned into E. coli K12 strain DH10B. Expression of fimbriae was dependent on culture conditions and sample handling. Specific immunolabeling of fimbriae unequivocally demonstrated the presence of all types of surface antigens investigated. Negative staining was effective in revealing CS3 but not CS6. In addition, this technique clearly demonstrated differences in the morphology of genetically and immunologically identical CS3 surface antigens in wild-type and recombinant strains. This paper provides a basis for the assessment of recombinant vaccines.

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