scholarly journals Efficient markerless integration of genes in the chromosome of probiotic E. coli Nissle 1917 by bacterial conjugation

2021 ◽  
Author(s):  
Elena M. Seco ◽  
Luis Ángel Fernández
Keyword(s):  
Bacterial Conjugation ◽  
E Coli

scholarly journals Antimicrobial resistance and R-plasmid in Salmonella spp from swine and abattoir environments

2004 ◽  
Vol 24 (2) ◽  
pp. 57-60 ◽  
Author(s):  
Norma S. Lázaro ◽  
Anita Tibana ◽  
Dália P. Rodrigues ◽  
Eliane M.F. Reis ◽  
Bianca R. Quintaes ◽  
...  
Keyword(s):  
Public Health ◽  
Gene Transfer ◽  
Antimicrobial Resistance ◽  
Animal Species ◽  
Bacterial Conjugation ◽  
Standard Strain ◽  
Salmonella Spp ◽  
Pathogenic Potential ◽  
E Coli ◽  
Transfer Phenomenon

Salmonella serovars isolated from swine are of particular interest not only because of the pathogenic potential for this animal species, but also due to its relevance with regard to public health. On basis of the profile of resistance to antimicrobials, 13 Salmonella strains were selected which belonged to the serovars Muenster (7), Derby (4), Typhimurium (1), and Braenderup (1). They were isolated from healthy swine as well as from the abattoir environment in the state of Rio de Janeiro. All strains of Salmonella were subjected to bacterial conjugation, and the E. coli K12 Nal r Lac+ F standard strain was used as receptor, with the purpose to verify the ability to transfer the resistance marks. Gene transfer phenomenon was detected in seven strains, and except SalmonellaTyphimurium which transconjugated to Sm, Tc and Su, the remaining ones were characterized by transferring mark Su only. By plasmidial analysis of strains used and their respective transconjugants, 63 Kb plasmid was found, which was probably related to S. Typhimurium resistance.

scholarly journals A quick and efficient method for interruption of bacterial conjugation

1965 ◽  
Vol 6 (2) ◽  
pp. 300-303 ◽  
Author(s):  
Brooks Low ◽  
T. H. Wood
Keyword(s):  
Efficient Method ◽  
Bacterial Conjugation ◽  
High Shear ◽  
Shear Forces ◽  
Entire Sample ◽  
Chromosome Transfer ◽  
E Coli ◽  
Sample Chamber ◽  
K 12 ◽  
Type Mixer

Jacob & Wollman (1961) produced interruption of chromosome transfer during conjugation in E. coli K-12 by exposing conjugating pairs to high shear forces created by a propeller-type mixer (a Waring blendor). In our laboratory, efforts to use this method were not completely successful because of the relatively long times required to ‘blend’ each sample and the large variations from sample to sample in the efficiency of separating mating couples (‘blending efficiency’). The variations in blending efficiency were thought to be due to lack of homogeneity of mixing in the blendor chamber. We have obtained much more satisfactory results by using a vibratory mixer which shakes the entire sample chamber and thoroughly agitates all the cells. Furthermore this vibratory blendor is much easier to use and permits taking at least twice as many samples per unit time, as compared to the usual blendor method.

scholarly journals Complete DNA Sequence, Comparative Genomics, and Prevalence of an IncHI2 Plasmid Occurring among Extraintestinal Pathogenic Escherichia coli Isolates

2006 ◽  
Vol 50 (11) ◽  
pp. 3929-3933 ◽  
Author(s):  
Timothy J. Johnson ◽  
Yvonne M. Wannemeuhler ◽  
Jennifer A. Scaccianoce ◽  
Sara J. Johnson ◽  
Lisa K. Nolan
Keyword(s):  
Escherichia Coli ◽  
Comparative Genomics ◽  
Dna Sequence ◽  
Antimicrobial Agents ◽  
Virulence Plasmid ◽  
Bacterial Conjugation ◽  
Large Plasmid ◽  
E Coli ◽  
Pathogenic Escherichia Coli

ABSTRACT We have sequenced a large plasmid that occurs among avian pathogenic Escherichia coli isolates. This plasmid, pAPEC-O1-R, is a 241,387-bp IncHI2 plasmid which is cotransmissible via bacterial conjugation with a ColBM virulence plasmid, encodes resistance to eight antimicrobial agents, and appears to occur at low rates among extraintestinal E. coli isolates.

scholarly journals Introduction of DNA into Actinomycetes by bacterial conjugation from E. coli—An evaluation of various transfer systems

2005 ◽  
Vol 120 (2) ◽  
pp. 146-161 ◽  
Author(s):  
Franca Blaesing ◽  
Agnes Mühlenweg ◽  
Silke Vierling ◽  
Günter Ziegelin ◽  
Stefan Pelzer ◽  
...  
Keyword(s):  
Bacterial Conjugation ◽  
E Coli

Identification of some Events in Bacterial Conjugation of E. Coli

1969 ◽  
Vol 27 ◽  
pp. 234-235
Author(s):  
Schreil W. ◽  
Christensen R.J. ◽  
Felluga B.
Keyword(s):  
Escherichia Coli ◽  
Cell Walls ◽  
Dna Transfer ◽  
Bacterial Chromosome ◽  
Bacterial Conjugation ◽  
E Coli ◽  
Receptor Cells ◽  
Cytoplasmic Membranes

In bacterial conjugation in the Escherichia coli system, two cells with heterosexual properties, donor and receptor cells, form a temporary pair and DNA is transferred up to the amount of a whole bacterial chromosome which would represent, if stretched out, a 1 mm long molecule. The physical mode of DNA transfer between two cells which have tight cell walls and cytoplasmic membranes is far from clear.

Endotoxin Alteration of the Mucopolysaccharide Blood Vessel Coating in Rats

1974 ◽  
Vol 32 ◽  
pp. 148-149
Author(s):  
D. E. Philpott ◽  
A. Takahashi
Keyword(s):  
Skeletal Muscle ◽  
Endothelial Cells ◽  
Salivary Gland ◽  
Carotid Artery ◽  
Basement Membrane ◽  
Coronary Vessels ◽  
Ruthenium Red ◽  
E Coli ◽  
Old Rats ◽  
The Brain

Two month, eight month and two year old rats were treated with 10 or 20 mg/kg of E. Coli endotoxin I. P. The eight month old rats proved most resistant to the endotoxin. During fixation the aorta, carotid artery, basil arartery of the brain, coronary vessels of the heart, inner surfaces of the heart chambers, heart and skeletal muscle, lung, liver, kidney, spleen, brain, retina, trachae, intestine, salivary gland, adrenal gland and gingiva were treated with ruthenium red or alcian blue to preserve the mucopolysaccharide (MPS) coating. Five, 8 and 24 hrs of endotoxin treatment produced increasingly marked capillary damage, disappearance of the MPS coating, edema, destruction of endothelial cells and damage to the basement membrane in the liver, kidney and lung.

Ribosome Structural Organization

1974 ◽  
Vol 32 ◽  
pp. 332-333
Author(s):  
James A. Lake
Keyword(s):  
Ribosomal Proteins ◽  
Structural Organization ◽  
Three Dimensional ◽  
Small Subunit ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Specific Antibodies ◽  
X Ray ◽  
E Coli ◽  
Complete Sequences

The understanding of ribosome structure has advanced considerably in the last several years. Biochemists have characterized the constituent proteins and rRNA's of ribosomes. Complete sequences have been determined for some ribosomal proteins and specific antibodies have been prepared against all E. coli small subunit proteins. In addition, a number of naturally occuring systems of three dimensional ribosome crystals which are suitable for structural studies have been observed in eukaryotes. Although the crystals are, in general, too small for X-ray diffraction, their size is ideal for electron microscopy.

Sites of Adsorption of the Bacteriophages T3 and T5 on the Wall of Escherichia Coli B.

1967 ◽  
Vol 25 ◽  
pp. 96-97
Author(s):  
Manfred E. Bayer
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Electron Microscope ◽  
Uranyl Acetate ◽  
E Coli ◽  
Receptor Sites ◽  
Rigid Cell Wall ◽  
Host Cell Surface ◽  
Bacterial Viruses ◽  
Escherichia Coli B

Bacterial viruses adsorb specifically to receptors on the host cell surface. Although the chemical composition of some of the cell wall receptors for bacteriophages of the T-series has been described and the number of receptor sites has been estimated to be 150 to 300 per E. coli cell, the localization of the sites on the bacterial wall has been unknown.When logarithmically growing cells of E. coli are transferred into a medium containing 20% sucrose, the cells plasmolize: the protoplast shrinks and becomes separated from the somewhat rigid cell wall. When these cells are fixed in 8% Formaldehyde, post-fixed in OsO4/uranyl acetate, embedded in Vestopal W, then cut in an ultramicrotome and observed with the electron microscope, the separation of protoplast and wall becomes clearly visible, (Fig. 1, 2). At a number of locations however, the protoplasmic membrane adheres to the wall even under the considerable pull of the shrinking protoplast. Thus numerous connecting bridges are maintained between protoplast and cell wall. Estimations of the total number of such wall/membrane associations yield a number of about 300 per cell.

Emigration of neutrophils in the central nervous system

1983 ◽  
Vol 41 ◽  
pp. 788-789
Author(s):  
John L.Beggs ◽  
John D. Waggener ◽  
Wanda Miller ◽  
Jane Watkins
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Osmium Tetroxide ◽  
White Blood Cells ◽  
Arterial Perfusion ◽  
E Coli ◽  
Intracisternal Injection ◽  
The Central Nervous System ◽  
Brain And Spinal Cord ◽  
Interendothelial Junctions

Studies using mesenteric and ear chamber preparations have shown that interendothelial junctions provide the route for neutrophil emigration during inflammation. The term emigration refers to the passage of white blood cells across the endothelium from the vascular lumen. Although the precise pathway of transendo- thelial emigration in the central nervous system (CNS) has not been resolved, the presence of different physiological and morphological (tight junctions) properties of CNS endothelium may dictate alternate emigration pathways.To study neutrophil emigration in the CNS, we induced meningitis in guinea pigs by intracisternal injection of E. coli bacteria.In this model, leptomeningeal inflammation is well developed by 3 hr. After 3 1/2 hr, animals were sacrificed by arterial perfusion with 3% phosphate buffered glutaraldehyde. Tissues from brain and spinal cord were post-fixed in 1% osmium tetroxide, dehydrated in alcohols and propylene oxide, and embedded in Epon. Thin serial sections were cut with diamond knives and examined in a Philips 300 electron microscope.

Use of Uranium-Labeled Antibodies for Electron Microscopic Localization of Various Antigens in Mammalian Cells

1967 ◽  
Vol 25 ◽  
pp. 136-137
Author(s):  
J. P. Petrali ◽  
E. J. Donati ◽  
L. A. Sternberger
Keyword(s):  
Endoplasmic Reticulum ◽  
Hela Cells ◽  
Mammalian Cells ◽  
Specific Antiserum ◽  
Electron Microscopic ◽  
E Coli ◽  
Cytoplasmic Membranes ◽  
Viral Progeny ◽  
Ultrathin Sections ◽  
Electron Microscopic Localization

Specific contrast is conferred to subcellular antigen by applying purified antibodies, exhaustively labeled with uranium under immunospecific protection, to ultrathin sections. Use of Seligman’s principle of bridging osmium to metal via thiocarbohydrazide (TCH) intensifies specific contrast. Ultrathin sections of osmium-fixed materials were stained on the grid by application of 1) thiosemicarbazide (TSC), 2) unlabeled specific antiserum, 3) uranium-labeled anti-antibody and 4) TCH followed by reosmication. Antigens to be localized consisted of vaccinia antigen in infected HeLa cells, lysozyme in monocytes of patients with monocytic or monomyelocytic leukemia, and fibrinogen in the platelets of these leukemic patients. Control sections were stained with non-specific antiserum (E. coli).In the vaccinia-HeLa system, antigen was localized from 1 to 3 hours following infection, and was confined to degrading virus, the inner walls of numerous organelles, and other structures in cytoplasmic foci. Surrounding architecture and cellular mitochondria were unstained. 8 to 14 hours after infection, antigen was localized on the outer walls of the viral progeny, on cytoplasmic membranes, and free in the cytoplasm. Staining of endoplasmic reticulum was intense and focal early, and weak and diffuse late in infection.

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