scholarly journals Genetically Modified Vibrio harveyiStrains as Potential Bioindicators of Mutagenic Pollution of Marine Environments

2000 ◽  
Vol 66 (2) ◽  
pp. 599-605 ◽  
Author(s):  
Agata Czyz˙ ◽  
Jacek Jasiecki ◽  
Adam Bogdan ◽  
Hanna Szpilewska ◽  
Grzegorz We˛grzyn
Keyword(s):  
Marine Bacterium ◽  
Genetically Modified ◽  
Marine Environments ◽  
Simple Method ◽  
Naturally Occurring ◽  
Low Concentrations ◽  
Serovar Typhimurium ◽  
Wild Type Counterpart ◽  
Mutagenic Pollution ◽  
Selection Of

ABSTRACT For biodetection of mutagenic pollution of marine environments, an organism naturally occurring in these habitats should be used. We found that marine bacterium Vibrio harveyi may be an appropriate bioindicator of mutagenic pollution. For positive selection of mutants, we developed a simple method for isolation of V. harveyimutants resistant to neomycin. We constructed genetically modifiedV. harveyi strains that produce significantly more neomycin-resistant mutants upon treatment with low concentrations of mutagens than the wild-type counterpart. The sensitivity of the mutagenicity test with the V. harveyi strains is at least comparable to (if not higher than) that of the commonly used Ames test, which uses Salmonella enterica serovar Typhimurium strains. Therefore, we consider that the V. harveyi strains described in this report could be used as potential bioindicators of mutagenic pollution of marine environments.

Optimization of the selection of analysis methods for the determination of naturally occurring radionuclides

Kerntechnik ◽  
2008 ◽  
Vol 73 (3) ◽  
pp. 118-121
Author(s):  
T. Heinrich ◽  
L. Funke ◽  
M. Köhler ◽  
U.-K. Schkade ◽  
F. Ullrich ◽  
...  
Keyword(s):  
Naturally Occurring ◽  
Analysis Methods ◽  
Naturally Occurring Radionuclides ◽  
Selection Of

scholarly journals Evaluating the impact of exposure to environmental contaminants on human health

1996 ◽  
Vol 42 (8) ◽  
pp. 1345-1349 ◽  
Author(s):  
J B Silkworth ◽  
J F Brown
Keyword(s):  
Chemical Substances ◽  
The Public ◽  
Aromatic Hydrocarbon Receptor ◽  
Naturally Occurring ◽  
Synthetic Chemicals ◽  
Low Concentrations ◽  
Polycyclic Aromatic ◽  
Coplanar Polychlorinated Biphenyls ◽  
Proportional Contribution ◽  
The Impact

Abstract Humans are exposed daily to low concentrations of many different chemical substances, natural and some man-made. Although many of these substances can be toxic at high levels, typical exposures are far below the effect levels. The responses produced by man-made aromatic hydrocarbon receptor agonists, such as dioxins, polychlorinated dibenzofurans, coplanar polychlorinated biphenyls, and polycyclic aromatic hydrocarbons, are also produced, often to greater extents [corrected], by naturally occurring constituents of fried meat, cabbage, broccoli, cauliflower, cocoa, and curry. Our society seems to be concerned about the health risks associated only with the synthetic chemicals, regardless of their proportional contribution to the total agonist activity, and regulates on the basis of such concerns. It would be more protective of the public health to determine acceptable concentrations for each type of response, regardless of the origin of the inducing agent, and issue advisories or regulations accordingly.

scholarly journals Contribution of Target Gene Mutations and Efflux to Decreased Susceptibility of Salmonella enterica Serovar Typhimurium to Fluoroquinolones and Other Antimicrobials

2006 ◽  
Vol 51 (2) ◽  
pp. 535-542 ◽  
Author(s):  
Sheng Chen ◽  
Shenghui Cui ◽  
Patrick F. McDermott ◽  
Shaohua Zhao ◽  
David G. White ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Efflux Pump ◽  
Critical Role ◽  
Gene Mutations ◽  
Efflux Pumps ◽  
Fluoroquinolone Resistance ◽  
Naturally Occurring ◽  
Serovar Typhimurium ◽  
Resistant Mutants ◽  
Increased Susceptibility

ABSTRACT The mechanisms involved in fluoroquinolone resistance in Salmonella enterica include target alterations and overexpression of efflux pumps. The present study evaluated the role of known and putative multidrug resistance efflux pumps and mutations in topoisomerase genes among laboratory-selected and naturally occurring fluoroquinolone-resistant Salmonella enterica serovar Typhimurium strains. Strains with ciprofloxacin MICs of 0.25, 4, 32, and 256 μg/ml were derived in vitro using serovar Typhimurium S21. These mutants also showed decreased susceptibility or resistance to many nonfluoroquinolone antimicrobials, including tetracycline, chloramphenicol, and several β-lactams. The expression of efflux pump genes acrA, acrB, acrE, acrF, emrB, emrD, and mdlB were substantially increased (≥2-fold) among the fluoroquinolone-resistant mutants. Increased expression was also observed, but to a lesser extent, with three other putative efflux pumps: mdtB (yegN), mdtC (yegO), and emrA among mutants with ciprofloxacin MICs of ≥32 μg/ml. Deletion of acrAB or tolC in S21 and its fluoroquinolone-resistant mutants resulted in increased susceptibility to fluoroquinolones and other tested antimicrobials. In naturally occurring fluoroquinolone-resistant serovar Typhimurium strains, deletion of acrAB or tolC increased fluoroquinolone susceptibility 4-fold, whereas replacement of gyrA double mutations (S83F D87N) with wild-type gyrA increased susceptibility >500-fold. These results indicate that a combination of topoisomerase gene mutations, as well as enhanced antimicrobial efflux, plays a critical role in the development of fluoroquinolone resistance in both laboratory-derived and naturally occurring quinolone-resistant serovar Typhimurium strains.

Study of Red Halophilic Bacteria in Solar Salt and Salted Fish: II. Bacto-oxgall as a Selective Agent for Differentiation

1956 ◽  
Vol 13 (2) ◽  
pp. 195-199 ◽  
Author(s):  
H. P. Dussault
Keyword(s):  
Halophilic Bacteria ◽  
Partial Identification ◽  
Selective Medium ◽  
Selective Agent ◽  
Simple Method ◽  
Solar Salt ◽  
Salted Fish ◽  
Low Concentrations ◽  
Fish Samples

A simple method, based on oxgall tolerance, is proposed for differentiating red halophilic bacteria commonly found in solar salt and discoloured salted codfish. Tests carried out on 18 strains isolated from various sources have shown that the rod forms are inhibited by low concentrations of Bacto-oxgall and that the coccus forms tolerate relatively high ones. Bacto-oxgall can thus be used as the basis of a simple selective medium. This test has been found useful for the isolation, purification and partial identification of unidentified strains and also for determining the relative proportions of the two main types of red halophilic bacteria present in solar salt and salted fish samples.

scholarly journals Selection of dancer member using simple additive weighting

2018 ◽  
Vol 7 (3) ◽  
pp. 1096 ◽  
Author(s):  
Hana Adela ◽  
Kamarul Azmi Jasmi ◽  
Bushrah Basiron ◽  
Miftachul Huda ◽  
Andino Maseleno
Keyword(s):  
Community Life ◽  
Simple Method ◽  
Unitary State ◽  
Simple Additive Weighting ◽  
Selection Of

Travel and dance form in Indonesia is closely related to the development of community life, both in terms of ethnic structure and within the scope of the unitary state. This study determines the criteria for selecting dancer members and how to apply the qualified Simple method. Based on predetermined criteria is the ability to dance physical flexibility, skilled, nimble, confident, have the ability, fill out the form, and certificate of achievement. From the results obtained values then V1, V2, V3, V4, V5 is a member of a qualified dancer and has a highest value with a score of 100 which was obtained from V2. 

scholarly journals Gelation or molecular recognition; is the bis-(α,β-dihydroxy ester)s motif an omnigelator?

2010 ◽  
Vol 6 ◽  
pp. 1079-1088 ◽  
Author(s):  
Peter C Griffiths ◽  
David W Knight ◽  
Ian R Morgan ◽  
Amy Ford ◽  
James Brown ◽  
...  
Keyword(s):  
Molecular Recognition ◽  
Neutron Scattering ◽  
Spin Echo ◽  
Inelastic Neutron ◽  
Gelation Mechanism ◽  
Regular Structures ◽  
Low Concentrations ◽  
Wide Range ◽  
History Of ◽  
Selection Of

Understanding the gelation of liquids by low molecular weight solutes at low concentrations gives an insight into many molecular recognition phenomena and also offers a simple route to modifying the physical properties of the liquid. Bis-(α,β-dihydroxy ester)s are shown here to gel thermoreversibly a wide range of solvents, raising interesting questions as to the mechanism of gelation. At gelator concentrations of 5–50 mg ml−1, gels were successfully formed in acetone, ethanol/water mixtures, toluene, cyclohexane and chloroform (the latter, albeit at a higher gelator concentration). A range of neutron techniques – in particular small-angle neutron scattering (SANS) – have been employed to probe the structure of a selection of these gels. The universality of gelation in a range of solvent types suggests the gelation mechanism is a feature of the bis-(α,β-dihydroxy ester) motif, with SANS demonstrating the presence of regular structures in the 30–40 Å range. A correlation between the apparent rodlike character of the structures formed and the polarity of the solvent is evident. Preliminary spin-echo neutron scattering studies (SESANS) indicated the absence of any larger scale structures. Inelastic neutron spectroscopy (INS) studies demonstrated that the solvent is largely unaffected by gelation, but does reveal insights into the thermal history of the samples. Further neutron studies of this kind (particularly SESANS and INS) are warranted, and it is hoped that this work will stimulate others to pursue this line of research.

scholarly journals Regulatory Effect of SlyA onrcsBExpression inSalmonella entericaSerovar Typhimurium

2018 ◽  
Vol 201 (4) ◽  
Author(s):  
María F. Ballesteros ◽  
Mónica F. Torrez Lamberti ◽  
Juan V. Farizano ◽  
María M. Pescaretti ◽  
Mónica A. Delgado
Keyword(s):  
Virulence Gene ◽  
Content Type ◽  
Virulence Gene Expression ◽  
Low Concentrations ◽  
Antagonistic Behavior ◽  
Serovar Typhimurium ◽  
Direct Binding ◽  
High Concentrations ◽  
Encoding Genes ◽  
Different Levels

ABSTRACTTheSalmonella entericaserovar Typhimurium RcsCDB system regulates the synthesis of colanic acid and the flagellum as well as the expression of virulence genes. We previously demonstrated that thercsC11mutant, which constitutively activates the RcsB regulator, attenuatesSalmonellavirulence in an animal model. This attenuated phenotype was also produced by deletion of theslyAgene. In this work, we investigated if this antagonistic behavior is produced by modulating the expression of both regulator-encoding genes. We demonstrated that SlyA overproduction negatively regulatesrcsBtranscription. A bioinformatics analysis enabled us to identify putative SlyA binding sites on both promoters, PrcsDBand PrcsB, which controlrcsBtranscriptional levels. We also determined that SlyA is able to recognize and bind to these predicted sites to modulate the activity of bothrcsBpromoters. According to these results, SlyA repressesrcsBtranscription by direct binding to specific sites located on thercsBpromoters, thus accounting for the attenuated/virulence antagonistic behaviors. Moreover, we showed that the opposite effect between both regulators also physiologically affects theSalmonellamotility phenotype. In this sense, we observed that under SlyA overproduction, PrcsBis repressed, and consequently, bacterial motility is increased. On the basis of these results, we suggest that during infection, the different RcsB levels produced act as a switch between the virulent and attenuated forms ofSalmonella. Thereby, we propose that higher concentrations of RcsB tilt the balance toward the attenuated form, while absence or low concentrations resulting from SlyA overproduction tilt the balance toward the virulent form.IMPORTANCEThe antagonistic behavior of RcsB and SlyA on virulence gene expression led us to hypothesize that there is interplay between both regulators in a regulatory network and these could be considered coordinators of this process. Here, we report that the SlyA virulence factor influences motility behavior by controllingrcsBtranscription from the PrcsBpromoter. We also demonstrate that SlyA negatively affects the expression of thercsBgene by direct binding to PrcsDBand PrcsBpromoters. We suggest that different levels of RcsB act as a switch between the virulent and attenuated forms ofSalmonella, where high concentrations of the regulator tend to tilt the balance toward the attenuated form and low concentrations or its absence tilt it toward the virulent form.

scholarly journals Root-specific expression of opine genes and opine accumulation in some cultivars of the naturally occurring genetically modified organismNicotiana tabacum

2016 ◽  
Vol 87 (3) ◽  
pp. 258-269 ◽  
Author(s):  
Ke Chen ◽  
François Dorlhac de Borne ◽  
Emilie Julio ◽  
Julie Obszynski ◽  
Patrick Pale ◽  
...  
Keyword(s):  
Genetically Modified ◽  
Specific Expression ◽  
Naturally Occurring

scholarly journals Transoperative refusion: a simple and safe method in emergency surgery

2014 ◽  
Vol 41 (4) ◽  
pp. 292-296
Author(s):  
Luiz Carlos Buarque Gusmão ◽  
Sérgio Henrique Chagas Valoes ◽  
José da Silva Leitão Neto
Keyword(s):  
Cost Benefit ◽  
Blood Transfusions ◽  
Factor V ◽  
West Nile Fever ◽  
Clotting Factors ◽  
Blood Contamination ◽  
Simple Method ◽  
Cost Benefit Ratio ◽  
The Cost ◽  
Selection Of

The objective is to reinforce the importance of blood reinfusion as a cheap, safe and simple method, which can be used in small hospitals, especially those in which there is no blood bank. Moreover, even with the use of devices that perform the collection and filtration of blood, more recent studies show that the cost-benefit ratio is much better when autologous transfusion is compared with blood transfusions, even when there is injury to hollow viscera and blood contamination. It is known that the allogeneic blood transfusion carries a number of risks to patients, among them are the coagulation disorders mediated by excess enzymes in the conserved blood, and deficiency in clotting factors, mainly the Factor V, the proacelerin. Another factor would be the risk of contamination with still unknown pathogens or that are not investigated during screening for selection of donors, such as the West Nile Fever and Creutzfeldt-Jacob, better known as "Mad Cow" disease. Comparing both methods, we conclude that blood autotransfusion has numerous advantages over heterologous transfusion, even in large hospitals. We are not against blood transfusions, just do not agree that the patient's own blood is discarded without making sure there will be enough blood in stock to get him out of the hemorrhagic shock.

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