Effect of gamma-ray irradiation on Escherichia coli motility

2014 ◽  
Vol 9 (10) ◽  
pp. 909-914 ◽  
Author(s):  
Tatsuo Atsumi ◽  
Eriko Fujimoto ◽  
Masakazu Furuta ◽  
Mikio Kato
Keyword(s):  
Escherichia Coli ◽  
Gamma Rays ◽  
Swimming Speed ◽  
Gamma Ray ◽  
Lethal Dose ◽  
Dependent Manner ◽  
Survival Ratio ◽  
Cellular Machinery ◽  
Cellular Dna ◽  
Dose Dependent

AbstractThe effects of ionizing radiation on bacteria are generally evaluated from the dose-dependent survival ratio, which is determined by colony-forming ability and mutation rate. The mutagenic damage to cellular DNA induced by radiation has been extensively investigated; however, the effects of irradiation on the cellular machinery in situ remain unclear. In the present work, we irradiated Escherichia coli cells in liquid media with gamma rays from 60Co (in doses up to 8 kGy). The swimming speeds of the cells were measured using a microscope. We found that the swimming speed was unaltered in cells irradiated with a lethal dose of gamma rays. However, the fraction of motile cells decreased in a dose-dependent manner. Similar results were observed when protein synthesis was inhibited by treatment with kanamycin. Evaluation of bacterial swimming speed and the motile fraction after irradiation revealed that some E. coli cells without the potential of cell growth and division remained motile for several hours after irradiation.

scholarly journals Effects of gamma rays from 60Co source on dwarf Dendrobium cross-breeding

2020 ◽  
Vol 19 (01) ◽  
pp. 32-40
Author(s):  
Vinh V. Nguyen
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Lethal Dose ◽  
Survival Ratio ◽  
Cross Breeding ◽  
60Co Source ◽  
60Co Gamma ◽  
Effective Doses ◽  
Higher Doses

In this research, seeds of DM12x13 dwarf Dendrobium cross-breeding germinated on (1 )/2 MS medium after 40 days were irradiated by 60Co source with various doses to determine LD50 (Lethal Dose 50%). After LD50 had been determined, protocorms of DM12x13 dwarf Dendrobium cross-breeding was irradiated by gamma rays from 60Co source in 5 doses: 0 Gy (control), 20 Gy, 40 Gy, 60 Gy and 80 Gy, dose rate 90 Gy/h to study the effect of gamma radiation on mutagenicity and evaluate the growth of these mutations in vitro. The result showed that the lethal dose of hybrid DM12x13 Dendrobium protocorm under the effect of 60Co gamma ray was 68 Gy. Survival ratio, growth and the ability to growth of plants reduced in higher doses and dead ratio were 100% when irradiated more than 80 Gy after 7 months. The effective doses for treating protocorm of DM12x13 crossbred lines were 20, 40 and 60 Gy. These doses were suitable for increased frequency of variation with generating wide-spread, diverse in structure and color of stems and leaves

scholarly journals Optimal Lethal Dose Determination for Gamma Rays and EMS Induced Mutagenesis in TMV7 and SVPR1 Sesame (Sesamum indicum L.) Varieties

2020 ◽  
pp. 136-144
Author(s):  
G. Parthasarathi ◽  
M. Arumugam Pillai ◽  
R. Kannan ◽  
S. Merina Prem Kumari ◽  
Asish K. Binodh
Keyword(s):  
Seed Germination ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Lethal Dose ◽  
Germination Percentage ◽  
Probit Analysis ◽  
Dependent Relationship ◽  
Methane Sulphonate ◽  
Induced Mutagenesis ◽  
Dose Dependent

In the present study two sesame varieties viz., TMV7 and SVPR1 were treated with varying doses of gamma rays (250, 300, 350, 400 and 450 Gy) and Ethyl Methane Sulphonate (EMS) of different concentrations viz.,0.20, 0.40 and 0.60%. The seed germination percentage was greatly affected by mutagenic treatment of gamma rays and EMS which showed a negative dose dependent relationship in both the varieties. The expected LD50 values were calculated through probit analysis. The LD50 values for TMV7 and SVPR1 were fixed at 416.86 Gy and 389.04 Gy for gamma rays and 0.490 % and 0.349% for EMS. The germination percentage of SVPR1 was greatly reduced (17.80 & 20.55 %) and the lethal dose to kill fifty per cent of mutated population was lower (6.68% & 28.78%) than that of TMV7 in both gamma ray and EMS treatment. EMS treatment exhibited significant reduction in seed germination (62.16 % & 66.67 %) than gamma irradiation (56.76 % & 54.55 %) in TMV7 and SVPR1 respectively. The study concluded that both the mutagens are effective to produce significant variations in sesame which can be further explored for mutation mapping.

Lethal Dose (LD50) Fixation and Sensitivity of Fenugreek (Trigonellafoenum-graecumL.) to Gamma Radiation for Induction of Mutation

2017 ◽  
Vol 4 (04) ◽  
Author(s):  
ANURADHA PATEL ◽  
POONAM VERMA ◽  
SHARDA CHOUDHARY ◽  
ARVIND KUMAR VERMA
Keyword(s):  
Genetic Variability ◽  
Gamma Rays ◽  
Growth Parameters ◽  
Seedling Survival ◽  
Lethal Dose ◽  
Germination Percentage ◽  
Mutation Breeding ◽  
Vigour Index ◽  
Small Flower ◽  
Dose Dependent

Fenugreek (Trigonella foenum-graecumL.) is an annual crop, mainly used as a spiceand leafy vegetable crop in many parts of the world. Classical breeding in fenugreek is restricted due to its low genetic variability and small flower size which hamper manual emasculation and pollination. Mutation breeding is an effective way to enrich genetic variability in crop plants. An experiment was conducted to determine the lethal dose of the physical mutagen gamma rays in fenugreek. The dry seeds of fenugreek were exposed to different doses of gamma rays i.e. 150Gy, 200Gy, 250Gy, 300Gy and 350Gy. These irradiated seeds were sown in the Petri plates with non-irradiated seeds (control). As the dose of gamma rays increased, there was a decrease in germination percentage, seedling survival, root length, shoot length and vigour index. Among five doses of gamma rays, the maximum seed germination was observed at lowest dose 150Gy (93%), followed by 200Gy (83%), 250Gy (76%), 300Gy (76%) and 350Gy (64%). The seedling survival was decreased from 90% (in control) to 56% in 350Gy dose of gamma rays. The gamma rays dose of 150Gy gave stimulatory effect on seedlings growth. The growth parameters were dose dependent, as the dose of gamma rays increased from 200Gy to 350Gy. The gamma rays dose of 350Gy showed 64% seeds germination and 56% of seedlings survival. Therefore, it is concluded that the LD50 dose for fenugreek is close to 350Gy. This information would be highly useful for initiating mutation breeding programme in fenugreek

scholarly journals Intracellular Free Iron and Its Potential Role in Ultrahigh-Pressure-Induced Inactivation of Escherichia coli

2012 ◽  
Vol 79 (2) ◽  
pp. 722-724 ◽  
Author(s):  
Yuan Yan ◽  
Joy G. Waite-Cusic ◽  
Periannan Kuppusamy ◽  
Ahmed E. Yousef
Keyword(s):  
Escherichia Coli ◽  
Iron Chelator ◽  
Ultrahigh Pressure ◽  
Dependent Manner ◽  
Paramagnetic Resonance ◽  
Free Iron ◽  
Content Type ◽  
E Coli ◽  
Electron Paramagnetic ◽  
Dose Dependent

ABSTRACTIntracellular free iron ofEscherichia coliwas determined by whole-cell electron paramagnetic resonance spectrometry. Ultrahigh pressure (UHP) increased both intracellular free iron and cell lethality in a pressure-dose-dependent manner. The iron chelator 2,2′-dipyridyl protected cells against UHP treatments. A mutation that produced iron overload conditions sensitizedE. colito UHP treatment.

Cloning and expression of a functional rat liver D-β-hydroxybutyrate dehydrogenase-β-galactosidase fusion protein in Escherichia coli

1991 ◽  
Vol 69 (9) ◽  
pp. 670-673
Author(s):  
Sharon Churchill ◽  
Perry Churchill
Keyword(s):  
Escherichia Coli ◽  
Rat Liver ◽  
Polyclonal Antibodies ◽  
Cloning And Expression ◽  
Dependent Manner ◽  
Bacteriophage Λ ◽  
Expression Library ◽  
Expression Plasmid ◽  
E Coli ◽  
Dose Dependent

A rat liver bacteriophage λ expression library was probed using polyclonal antibodies raised to purified rat liver D-β-hydroxybutyrate dehydrogenase (BDH). A clone was selected that contained a 1.2-kb insert. The insert placed in an expression plasmid was utilized to transform Escherichia coli. These cells were shown to possess phosphatidylcholine-dependent BDH activity. Cells transformed with only the plasmid had no detectable BDH activity in the presence of phosphatidylcholine. The expressed activity in E. coli could be inhibited in a dose-dependent manner by BDH antiserum.Key words: D-β-hydroxybutyrate dehydrogenase, cloning, expression.

scholarly journals The Escherichia coli Common Pilus and the Bundle-Forming Pilus Act in Concert during the Formation of Localized Adherence by Enteropathogenic E. coli

2009 ◽  
Vol 191 (11) ◽  
pp. 3451-3461 ◽  
Author(s):  
Zeus Saldaña ◽  
Ayşen L. Erdem ◽  
Stephanie Schüller ◽  
Iruka N. Okeke ◽  
Mark Lucas ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cells ◽  
Cultured Cells ◽  
Dependent Manner ◽  
Triple Mutant ◽  
E Coli ◽  
Accessory Factor ◽  
Isogenic Mutants ◽  
Dose Dependent ◽  
Background Expression

ABSTRACT Although the bundle-forming pilus (BFP) of enteropathogenic Escherichia coli (EPEC) mediates microcolony formation on epithelial cells, the adherence of BFP-deficient mutants is significantly abrogated, but the mutants are still adherent due to the presence of intimin and possibly other adhesins. In this study we investigated the contribution of the recently described E. coli common pilus (ECP) to the overall adherence properties of EPEC. We found that ECP and BFP structures can be simultaneously observed in the course (between zero time and 7 h during infection) of formation of localized adherence on cultured epithelial cells. These two pilus types colocalized at different levels of the microcolony topology, tethering the adhering bacteria. No evidence of BFP disappearance was found after prolonged infection. When expressed from a plasmid present in nonadherent E. coli HB101, ECP rendered this organism highly adherent at levels comparable to those of HB101 expressing the BFP. Purified ECP bound in a dose-dependent manner to epithelial cells, and the binding was blocked with anti-ECP antibodies, confirming that the pili possess adhesin properties. An ECP mutant showed only a modest reduction in adherence to cultured cells due to background expression levels of BFP and intimin. However, isogenic mutants not expressing EspA or BFP were significantly less adherent when the ecpA gene was also deleted. Furthermore, a ΔespA ΔecpA double mutant (unable to translocate Tir and to establish intimate adhesion) was at least 10-fold less adherent than the ΔespA and ΔecpA single mutants, even in the presence of BFP. A Δbfp ΔespA ΔecpA triple mutant showed the least adherence compared to the wild type and all the isogenic mutant strains tested, suggesting that ECP plays a synergistic role in adherence. Our data indicate that ECP is an accessory factor that, in association with BFP and other adhesins, contributes to the multifactorial complex interaction of EPEC with host epithelial cells.

scholarly journals Virulent Bacteriophages Can Target O104:H4 Enteroaggregative Escherichia coli in the Mouse Intestine

2012 ◽  
Vol 56 (12) ◽  
pp. 6235-6242 ◽  
Author(s):  
Damien Maura ◽  
Matthieu Galtier ◽  
Chantal Le Bouguénec ◽  
Laurent Debarbieux
Keyword(s):  
Escherichia Coli ◽  
Dependent Manner ◽  
Content Type ◽  
Intestinal Pathogens ◽  
Colonization Model ◽  
Mouse Intestine ◽  
Further Development ◽  
Dose Dependent

ABSTRACTIn vivobacteriophage targeting of enteroaggregativeEscherichia coli(EAEC) was assessed using a mouse intestinal model of colonization with the O104:H4 55989Str strain and a cocktail of three virulent bacteriophages. The colonization model was shown to mimic asymptomatic intestinal carriage found in humans. The addition of the cocktail to drinking water for 24 h strongly decreased ileal and weakly decreased fecal 55989Str concentrations in a dose-dependent manner. These decreases in ileal and fecal bacterial concentrations were only transient, since 55989Str concentrations returned to their original levels 3 days later. These transient decreases were independent of the mouse microbiota, as similar results were obtained with axenic mice. We studied the infectivity of each bacteriophage in the ileal and fecal environments and found that 55989Str bacteria in the mouse ileum were permissive to all three bacteriophages, whereas those in the feces were permissive to only one bacteriophage. Our results provide the first demonstration that bacterial permissivity to infection with virulent bacteriophages is not uniform throughout the gut; this highlights the need for a detailed characterization of the interactions between bacteria and bacteriophagesin vivofor the further development of phage therapy targeting intestinal pathogens found in the gut of asymptomatic human carriers.

scholarly journals Significant passive protective effect against anthrax by antibody to Bacillus anthracis inactivated spores that lack two virulence plasmids

Microbiology ◽  
2006 ◽  
Vol 152 (10) ◽  
pp. 3103-3110 ◽  
Author(s):  
Jargalsaikhan Enkhtuya ◽  
Keiko Kawamoto ◽  
Yoshiyasu Kobayashi ◽  
Ikuo Uchida ◽  
Neeraj Rana ◽  
...  
Keyword(s):  
Protective Effect ◽  
Bacillus Anthracis ◽  
Protective Antigen ◽  
Lethal Dose ◽  
Dependent Manner ◽  
Protective Effects ◽  
Virulence Plasmids ◽  
Somatic Antigens ◽  
Dose Dependent ◽  
Formalin Fixed

The protective-antigen (PA)-based cell-free vaccine is the only vaccine licensed for use against Bacillus anthracis infection in humans. Although the PA shows strong immunogenicity, the capsule or spore-associated somatic antigens may be important as additional vaccine targets for full protection against anthrax. In this study, the protective effect of spore-associated antigens against B. anthracis infection was determined. Rabbits were immunized with formalin-fixed spores of a non-toxigenic unencapsulated B. anthracis strain that lacked the two virulence plasmids pXO1 and pXO2, and the protective effects of the immune antibody were evaluated. Immunostaining and Western blot analysis revealed that the anti-B. anthracis (anti-BA)-spore IgG specifically bound to the surface of spores or endospores of B. anthracis, but not to vegetative cells, or closely related Bacillus species, such as Bacillus cereus, Bacillus subtilis and Bacillus thuringiensis. Passively transferred anti-BA-spore IgG protected mice from intraperitoneal challenge with a lethal dose of fully virulent B. anthracis spores, and increased the survival rate in a dose-dependent manner. Pre-incubation of spores with antibody also reduced their infectivity in a dose-dependent manner. The number of bacteria (c.f.u.) in spleens and livers of infected mice was significantly lower in antibody-treated mice than in untreated mice. Treatment with anti-BA-spore IgG also inhibited the germination of spores in J774.1 macrophages, suggesting that opsonization of spores promotes phagocytosis and subsequent killing by macrophages. These results indicate the usefulness of spore surface antigens as vaccine targets. In combination with major virulence factors such as the PA, spore-associated antigens may offer a safer and more effective multicomponent vaccine for B. anthracis infection.

scholarly journals Characterization of RNA damage under oxidative stress in Escherichia coli

2012 ◽  
Vol 393 (3) ◽  
pp. 123-132 ◽  
Author(s):  
Min Liu ◽  
Xin Gong ◽  
Ravi Kumar Alluri ◽  
Jinhua Wu ◽  
Tene’ Sablo ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Short Exposure ◽  
Dependent Manner ◽  
Ribosomal Rnas ◽  
Rna Oxidation ◽  
Folded Rna ◽  
Dose Dependent

Abstract We have examined the level of 8-hydroxyguanosine (8-oxo-G), an oxidized form of guanosine, in RNA in Escherichia coli under normal and oxidative stress conditions. The level of 8-oxo-G in RNA rises rapidly and remains high for hours in response to hydrogen peroxide (H2O2) challenge in a dose-dependent manner. H2O2 induced elevation of 8-oxo-G content is much higher in RNA than that of 8-hydroxydeoxyguanosine (8-oxo-dG) in DNA. Under normal conditions, the 8-oxo-G level is low in RNA isolated from the ribosome and it is nearly three times higher in non-ribosomal RNAs. In contrast, 8-oxo-G generated by a short exposure to H2O2 is almost equally distributed in various RNA species, suggesting that although ribosomal RNAs are normally less oxidized, they are not protected against exogenous H2O2. Interestingly, highly folded RNA is not protected from oxidation because 8-oxo-G generated by H2O2 treatment in vitro increases to approximately the same levels in tRNA and rRNA in both native and denatured forms. Lastly, increased RNA oxidation is closely associated with cell death by oxidative stress. Our data suggests that RNA is a primary target for reactive oxygen species and RNA oxidation is part of the paradox that cells have to deal with under oxidative stress.

scholarly journals Comparison of the Effects of Deferiprone versus Deferoxamine on Growth and Virulence of Yersinia enterocolitica

2002 ◽  
Vol 46 (6) ◽  
pp. 1741-1745 ◽  
Author(s):  
Biliana Lesic ◽  
Jeannine Foulon ◽  
Elisabeth Carniel
Keyword(s):  
Chelation Therapy ◽  
Lethal Dose ◽  
Iron Chelation ◽  
Defined Medium ◽  
Dependent Manner ◽  
Chemically Defined Medium ◽  
Mouse Model Of Infection ◽  
Orally Active ◽  
Dose Dependent

ABSTRACT Deferoxamine, a drug used to treat patients with iron overload, has the capacity to promote systemic Y. enterocolitica infections in humans. The aim of this study was to determine whether deferiprone, the only orally active alternative treatment, has the same potential. When Y. enterocolitica IP864 was grown in an iron-poor chemically defined medium, addition of deferoxamine promoted its growth, while various concentrations of deferiprone did not display this activity. Similarly, on iron-poor agar plates, various Y. enterocolitica strains were able to grow around paper disks impregnated with deferoxamine in a dose-dependent manner, while no growth was observed around the deferiprone disks. In a mouse experimental model of infection, the 50% lethal dose (LD50) of strain IP864 was decreased by more than 5 log units in mice pretreated with deferoxamine, while a deferiprone pretreatment did not affect it. Therefore, in contrast to deferoxamine, deferiprone does not enhance growth of pathogenic Y. enterocolitica in vitro and does not have the potential to promote Y. enterocolitica septicemia in a mouse model of infection. Deferiprone may thus represent a useful alternative iron-chelation therapy during invasive Y. enterocolitica infections.

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