scholarly journals A study of pili onPseudomonas aeruginosa

1972 ◽  
Vol 19 (1) ◽  
pp. 39-51 ◽  
Author(s):  
David E. Bradley
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Current Knowledge ◽  
Genetic Material ◽  
Filamentous Phage ◽  
Supporting Evidence ◽  
Bacterial Strains ◽  
Structural Comparison ◽  
Male Specific ◽  
Rna Phage

SUMMARYPseudomonas aeruginosacarries polar pili which act as receptors for RNA-containing bacteriophages. In order to confirm, that these pili were not involved in the transfer of the sex factor FP 2, eleven bacterial strains, both FP 2+and FP 2−, were examined in the electron microscope for the presence of pili and tested for sensitivity to the RNA phage PP7. Pili were found on all strains save one which was resistant to phage PP7. It was also found by electron microscopy that about 25 times more pili per cell were present after PP7 adsorption than before it. This result is discussed with reference to the pilus retraction theory, providing further evidence that some kinds of pili retract instead of acting as simple tubes for the transfer of genetic material. The strong supporting evidence provided by the infective processes of male-specific coliphages is discussed and compared to current knowledge ofP. aeruginosaRNA phages.It was also found that pili were present on the host strain for theP. aeruginosafilamentous phage Pf. Although similar in appearance to RNA phage pili, these differed in that they did not adsorb phage PP7. However, it seemed likely that they were receptors for Pf. A structural comparison is made betweenP. aeruginosapili andEscherichia coliF-pili. It is possible thatP. aeruginosapili could be coded for by a plasmid other than FP 2.

scholarly journals Cryo-Transmission Electron Microscopy of Frozen-Hydrated Sections of Escherichia coli and Pseudomonas aeruginosa

2003 ◽  
Vol 185 (20) ◽  
pp. 6112-6118 ◽  
Author(s):  
Valério R. F. Matias ◽  
Ashraf Al-Amoudi ◽  
Jacques Dubochet ◽  
Terry J. Beveridge
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Genetic Material ◽  
Supporting Evidence ◽  
Periplasmic Space ◽  
High Pressure Freezing ◽  
Transmission Electron ◽  
K 12 ◽  
Peptidoglycan Layer

ABSTRACT High-pressure freezing of Escherichia coli K-12 and Pseudomonas aeruginosa PAO1 in the presence of cryoprotectants provided consistent vitrification of cells so that frozen-hydrated sections could be cut, providing ∼2-nm resolution of structure. The size and shape of the bacteria, as well as their surface and cytoplasmic constituents, were nicely preserved and compared well with other published high-resolution techniques. Cells possessed a rich cytoplasm containing a diffuse dispersion of ribosomes and genetic material. Close examination of cells revealed that the periplasmic space was compressed during cryosectioning, a finding which provided supporting evidence that this space is filled by a compressible gel. Since the outer membrane and peptidoglycan layer are bonded together via lipoproteins, the space between them (although still part of the periplasmic space) was not as compacted. Even when this cryosectioning compression was taken into account, there was still substantial variability in the width of the periplasmic space. It is possible that the protoplast has some capacity to float freely within the periplasm.

scholarly journals The Isolation and Oharacterization of An Rna Bacteriophage

1964 ◽  
Vol 17 (3) ◽  
pp. 719 ◽  
Author(s):  
CI Davern
Keyword(s):  
Escherichia Coli ◽  
Dna Synthesis ◽  
Culture Medium ◽  
Buoyant Density ◽  
Sedimentation Coefficient ◽  
Caesium Chloride ◽  
Specific Phage ◽  
K 12 ◽  
Male Specific ◽  
Rna Phage

An enrichment procedure for the isolation of RNA bacteriophage is described. The method involves the inoculation of sewage samples into cultures of Escherichia coli K-12 Hfr under conditions where DNA synthesis is restricted by the addition of 5-fiuorodeoxyuridine to the culture medium. Six phage isolates were made and all of them were shown to be male-specific. One of the male-specific phage was further characterized as an RNA phage, having very similar properties to RNA phage already isolated in other parts oftha world. This RNA phage has a buoyant density of 1�42 g/cm3 in caesium chloride. and has a sedimentation coefficient of 79'5 Sin O'Ol:M Tria-HOI buffer, pH 7� 4, at 20�0.

scholarly journals Various morphological aspects of Escherichia coli lysis by two distinct RNA bacteriophages

2002 ◽  
Vol 83 (10) ◽  
pp. 2601-2606 ◽  
Author(s):  
Tohru Nishihara
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Cell Wall ◽  
Cell Surfaces ◽  
Morphological Aspects ◽  
Lysis Gene ◽  
Transmission Electron ◽  
Group A ◽  
Group B ◽  
Rna Phage

Transmission electron micrographs of Escherichia coli cells induced by cloned lysis genes from RNA bacteriophages GA (group A-II) and SP (group B-IV) revealed various morphological aspects of intermediates of lysing cells. Cells induced by the SP lysis gene became stretched and also tapered in shape and fragmentation of parts of the cells had also occurred. Cells induced by the GA lysis gene showed many ballooning structures on the cell surfaces and others leaked material through the cell wall. Some balloon-like structures also appeared on the surfaces of cells induced by the cloned lysis gene of RNA phage SP and material also appeared to be leaking through the cell wall in the photographs. The lysing cells observed by transmission electron microscopy showed various morphological aspects of intermediates of the lysing process.

scholarly journals Protective Effects of Natural Products and Their Derivatives on Genetic Material: A Critical Review

2021 ◽  
Vol 15 (6) ◽  
pp. 433-462
Author(s):  
Muhammad Torequl Islam ◽  
Cristina Quispe ◽  
Mohammad S. Mubarak ◽  
Bahare Salehi ◽  
Željko Reiner ◽  
...  
Keyword(s):  
Natural Products ◽  
Current Knowledge ◽  
Genetic Material ◽  
Micronucleus Assay ◽  
Dna Lesions ◽  
Protective Effects ◽  
Bacterial Strains ◽  
Animal Cells ◽  
Carcinogenic Agent ◽  
Test Systems

Although treatment with natural products and the substances derived from them has gained much attention, it is important to know the genomic safety of these substances prior to their use in humans. The present review aims to present the current knowledge on the genoprotective effects and possible mechanism of actions of natural compounds. Therefore, an up-to-date search was conducted using known databases such as PubMed, ScienceDirect, and Clinicaltrials.gov. For the investigation of genotoxic/genoprotective activity of these substances, comet or micronucleus assay were frequently used models applied through eukaryotic test systems, bacterial strains, cultured animal cells or tissues (e.g., mice, rats) but also human by using oxidizing or carcinogenic agent-induced DNA damage capacity. Findings suggest that several extracts, including those from medicinal plants, marine algae or their preparations, antioxidants such as quercetin, retinoids, resveratrol, hyaluronic acid, carnosol, rosmarinic acid, and naringin have shown genoprotective effects in various test systems. Antioxidant, anti-inflammatory, mitogenic, reduction of DNA strand breaks and DNA lesions, formation of micronucleus, and chromosomal aberrations were the observed mechanisms of action of genoprotective substances. In conclusion, this review highlights the importance of natural products, especially dietary antioxidants, which can be safely used for the treatment of various diseases.

scholarly journals Host specificities of RNA phages

1972 ◽  
Vol 70 (1) ◽  
pp. 55-61 ◽  
Author(s):  
Sheena Dennison ◽  
R. W. Hedges
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Male Specific ◽  
Rna Phage

SUMMARYHost ranges of members of four groups of male-specific RNA coliphages were determined by plating on hosts carrying various derepressed plasmids. An RNA phage originally isolated onPseudomonas aeruginosafailed to form plaques on any of the strains ofEscherichia coli.

scholarly journals Salmonella hybrids containing genic material of multiple origins

1971 ◽  
Vol 17 (2) ◽  
pp. 133-138
Author(s):  
F. B. Armstrong ◽  
George F. Sprague
Keyword(s):  
Escherichia Coli ◽  
Minimal Medium ◽  
Genetic Material ◽  
Low Frequency ◽  
The Other ◽  
Supporting Evidence ◽  
Biosynthetic Pathways ◽  
Multiple Origins ◽  
Base Sequences ◽  
Close Relatedness

SUMMARYBacterial hybrids were produced to contain genetic material ofSalmonella typhimurium, Escherichia coli, S. montevideoandS. abonyorigins. Analyses by transduction provide evidence that 6% of the originaltyphimuriumgenome has been replaced in the production of these hybrids. Although a number of biosynthetic pathways are affected by this gene substitution, the growth rate of these hybrids in minimal medium is unchanged. Supporting evidence for the close relatedness betweenS. typhimuriumand the other three species is not observed in recombination studies. Available results favour the concept that differences in base sequences are responsible for the low frequency of recombination obtained in heterologous crosses.

Structural organization of escherichia coli ribosomes as determined by immuno electron microscopy

1978 ◽  
Vol 36 (2) ◽  
pp. 166-167 ◽  
Author(s):  
G. Stöffler ◽  
R.W. Bald ◽  
J. Dieckhoff ◽  
H. Eckhard ◽  
R. Lührmann ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Ribosomal Proteins ◽  
Structural Organization ◽  
Three Dimensional ◽  
Ribosomal Subunit ◽  
Spatial Arrangement ◽  
Small Subunit ◽  
Antibody Binding ◽  
Immuno Electron Microscopy

A central step towards an understanding of the structure and function of the Escherichia coli ribosome, a large multicomponent assembly, is the elucidation of the spatial arrangement of its 54 proteins and its three rRNA molecules. The structural organization of ribosomal components has been investigated by a number of experimental approaches. Specific antibodies directed against each of the 54 ribosomal proteins of Escherichia coli have been performed to examine antibody-subunit complexes by electron microscopy. The position of the bound antibody, specific for a particular protein, can be determined; it indicates the location of the corresponding protein on the ribosomal surface.The three-dimensional distribution of each of the 21 small subunit proteins on the ribosomal surface has been determined by immuno electron microscopy: the 21 proteins have been found exposed with altogether 43 antibody binding sites. Each one of 12 proteins showed antibody binding at remote positions on the subunit surface, indicating highly extended conformations of the proteins concerned within the 30S ribosomal subunit; the remaining proteins are, however, not necessarily globular in shape (Fig. 1).

Phyto-fabrication of Iron Nanoparticles: Characterization and Antibacterial Capacity

2020 ◽  
Vol 16 ◽  
Author(s):  
Asma S. Algebaly ◽  
Afrah E. Mohammed ◽  
Mudawi M. Elobeid
Keyword(s):  
Electron Microscopy ◽  
Plant Extracts ◽  
Large Scale ◽  
Iron Nanoparticles ◽  
Ethanolic Extract ◽  
Green Technology ◽  
Resistant Bacteria ◽  
Scale Production ◽  
Bacterial Strains ◽  
Plant Sources

Introduction: Fabrication of iron nanoparticles (FeNPs) has recently gained a great concern for their varied applications in remediation technologies of the environment. Objective: The current study aimed to fabricate iron nanoparticles by green technology approach using different plant sources, Azadirachta indica leaf and Calligonum comosum root following two extraction methods. Methods: Currently, a mixture of FeCl2 and FeCl3 was used to react with the plant extracts which are considered as reducing and stabilizing agents for the generation of FeNPs in one step. Different techniques were used for FeNPs identification. Results: Immediately after mixing of the two reaction components, the color changed to dark brown as an indication of safe conversion of Fe ions to FeNPs, that later confirmed by zeta sizer, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). FeNPs fabricated by C. comosum showed smaller size when compared by those fabricated by A. indica. Using both plant sources, FeNPs fabricated by the aqueous extract had smaller size in relation to those fabricated by ethanolic extract. Furthermore, antibacterial ability against two bacterial strains was approved. Conclusion: The current results indicated that, at room temperature plant extracts fabricated Fe ion to Fe nanoparticles, suggesting its probable usage for large scale production as well as its suitability against bacteria. It could also be recommended for antibiotic resistant bacteria.

scholarly journals Antimicrobial activity of Syzygium aromaticum L. essential oil on extended-spectrum beta-lactamases-producing Escherichia coli

2020 ◽  
Vol 44 (1) ◽  
Author(s):  
E. L. Mejía-Argueta ◽  
J. G. Santillán-Benítez ◽  
M. M. Canales-Martinez ◽  
A. Mendoza-Medellín
Keyword(s):  
Escherichia Coli ◽  
Essential Oil ◽  
Genetic Material ◽  
Gastrointestinal Diseases ◽  
Syzygium Aromaticum ◽  
Antibiotic Resistant ◽  
Plant Essential Oils ◽  
E Coli ◽  
Extended Spectrum ◽  
Tract Infections

Abstract Background To test the antimicrobial potential of clove essential oil that has been less investigated on antimicrobial-resistant organisms (extended-spectrum β-lactamase-ESBL-producing Escherichia coli), we collected 135 ESBL-producing Escherichia coli strains given that E. coli is the major organism increasingly isolated as a cause of complicated urinary and gastrointestinal tract infections, which remains an important cause of therapy failure with antibiotics for the medical sector. Then, in this study, we evaluated the relationship between the antibacterial potential activity of Syzygium aromaticum essential oil (EOSA) and the expression of antibiotic-resistant genes (SHV-2, TEM-20) in plasmidic DNA on ESBL-producing E. coli using RT-PCR technique. Results EOSA was obtained by hydrodistillation. Using Kirby-Baüer method, we found that EOSA presented a smaller media (mean = 15.59 mm) in comparison with chloramphenicol (mean = 17.73 mm). Thus, there were significant differences (p < 0.0001). Furthermore, EOSA had an antibacterial activity, particularly on ECB132 (MIC: 10.0 mg/mL and MBC: 80.0 mg/mL), and a bacteriostatic effect by bactericidal kinetic. We found that the expression of antibiotic-resistant gene blaTEM-20 was 23.52% (4/17 strains) and no expression of blaSHV-2. EOSA presented such as majority compounds (eugenol, caryophyllene) using the GC–MS technique. Conclusions Plant essential oils and their active ingredients have potentially high bioactivity against a different target (membranes, cytoplasm, genetic material). In this research, EOSA might become an important adjuvant against urinary and gastrointestinal diseases caused by ESBL-producing E. coli.

Sign in / Sign up

Export Citation Format

Share Document