scholarly journals Relevance of Biofilms in the Pathogenesis of Shiga-Toxin-ProducingEscherichia coliInfection

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Natalia Angel Villegas ◽  
José Baronetti ◽  
Inés Albesa ◽  
Rosana Polifroni ◽  
Alberto Parma ◽  
...  
Keyword(s):  
Shiga Toxin ◽  
Biofilm Formation ◽  
Vero Cells ◽  
Oxygen Species ◽  
Cytotoxic Effects ◽  
Cytotoxicity Studies ◽  
Reactive Nitrogen Intermediates ◽  
Low Levels ◽  
High Level ◽  
Griess Assay

The present study was designed to determine the relationships among biofilm formation, cellular stress and release of Shiga toxin (Stx) by three different clinical Shiga toxin-producingEscherichia coli(STEC) strains. The biofilm formation was determined using crystal violet stain in tryptic soy broth or thioglycollate medium with the addition of sugars (glucose or mannose) or hydrogen peroxide. The reactive oxygen species (ROSs) were detected by the reduction of nitro blue tetrazolium and reactive nitrogen intermediates (RNI) determined by the Griess assay. In addition, the activities of two antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), were studied. For the cytotoxicity studies, Vero cells were cultured with Stx released of STEC biofilms. The addition of sugars in both culture mediums resulted in an increase in biofilm biomass, with a decrease in ROS and RNI production, low levels of SOD and CAT activity, and minimal cytotoxic effects. However, under stressful conditions, an important increase in the antioxidant enzyme activity and high level of Stx production were observed. The disturbance in the prooxidant-antioxidant balance and its effect on the production and release of Stx evaluated under different conditions of biofilm formation may contribute to a better understanding of the relevance of biofilms in the pathogenesis of STEC infection.

scholarly journals The Deleterious Effects of Shiga Toxin Type 2 Are Neutralized In Vitro by FabF8:Stx2 Recombinant Monoclonal Antibody

Toxins ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 825
Author(s):  
Daniela Luz ◽  
Fernando D. Gómez ◽  
Raíssa L. Ferreira ◽  
Bruna S. Melo ◽  
Beatriz E. C. Guth ◽  
...  
Keyword(s):  
Shiga Toxin ◽  
Therapeutic Option ◽  
Primary Cultures ◽  
Age Groups ◽  
Vero Cells ◽  
Dependent Manner ◽  
Cytotoxic Effects ◽  
Uremic Syndrome

Hemolytic Uremic Syndrome (HUS) associated with Shiga-toxigenic Escherichia coli (STEC) infections is the principal cause of acute renal injury in pediatric age groups. Shiga toxin type 2 (Stx2) has in vitro cytotoxic effects on kidney cells, including human glomerular endothelial (HGEC) and Vero cells. Neither a licensed vaccine nor effective therapy for HUS is available for humans. Recombinant antibodies against Stx2, produced in bacteria, appeared as the utmost tool to prevent HUS. Therefore, in this work, a recombinant FabF8:Stx2 was selected from a human Fab antibody library by phage display, characterized, and analyzed for its ability to neutralize the Stx activity from different STEC-Stx2 and Stx1/Stx2 producing strains in a gold standard Vero cell assay, and the Stx2 cytotoxic effects on primary cultures of HGEC. This recombinant Fab showed a dissociation constant of 13.8 nM and a half maximum effective concentration (EC50) of 160 ng/mL to Stx2. Additionally, FabF8:Stx2 neutralized, in different percentages, the cytotoxic effects of Stx2 and Stx1/2 from different STEC strains on Vero cells. Moreover, it significantly prevented the deleterious effects of Stx2 in a dose-dependent manner (up to 83%) in HGEC and protected this cell up to 90% from apoptosis and necrosis. Therefore, this novel and simple anti-Stx2 biomolecule will allow further investigation as a new therapeutic option that could improve STEC and HUS patient outcomes.

Antibacterial and Cytotoxic Effects of Silver Nanoparticles on Staphylococcus aureus and Normal Vero Cells

2019 ◽  
Vol 22 (10) ◽  
pp. 184-190
Author(s):  
Rasha Hadi Saleh ◽  
Entisar J. Al-Mukhtar ◽  
Zaytoon A. Al-Khafaji ◽  
Mohammed H. Al Hasnawy ◽  
Huda H. Al-Hasnawy
Keyword(s):  
Staphylococcus Aureus ◽  
Silver Nanoparticles ◽  
Vero Cells ◽  
Cytotoxic Effects

High world sugar prices: is Asia’s production cycle to blame?

2010 ◽  
pp. 169-173
Author(s):  
Martin Todd
Keyword(s):  
Supply Chain ◽  
Supply And Demand ◽  
Production Cycle ◽  
Low Levels ◽  
High Level ◽  
High World

The current high world sugar prices reflect a major imbalance between global supply and demand, which has reduced stocks to very low levels. Although it remains to be seen whether prices will rise much above current values, it is clear that the supply chain will remain stretched throughout 2010 and this will help to maintain prices at a high level.

Toxic Effect of 2-ethyl (bicyclo[2.2.1] heptane) on Bacterial Cells

2019 ◽  
Vol 35 (6) ◽  
pp. 67-72 ◽  
Author(s):  
I.V. Manukhov ◽  
L.S. Yaguzhinsky ◽  
M.V. Bermeshev ◽  
M.A. Zisman ◽  
V.G. Pevgov ◽  
...  
Keyword(s):  
Toxic Effect ◽  
Atmospheric Oxygen ◽  
Inducible Promoter ◽  
Oxygen Species ◽  
Bacterial Cells ◽  
Unique Identifier ◽  
E Coli ◽  
Lux Biosensors ◽  
High Level ◽  
Ministry Of Higher Education

Toxic effect of 2-ethylnorbornane (2-ethyl(bicyclo[2.2.1]heptane) (EBH)) on bacteria has been studied using the E. coli pRecA-lux and E. coli pKatG- lux cells as lux-biosensors. It was shown that the addition of EBH to the incubation medium leads to death and growth retardation, high level oxidative stress and DNA damage in E. coli cells. It is assumed that the oxidation of EBH with atmospheric oxygen causes the formation of reactive oxygen species in the medium, which makes a major contribution to the toxicity of this substance. biosensor, luciferase, bioluminescence, inducible promoter, PrecA, PkatG The authors are grateful to Stanislav Filippovich Chalkin for the development of interdisciplinary ties in the scientific community. The work was financially supported by the Ministry of Higher Education and Science of Russia (Project Unique Identifier RFMEFI60417X0181, Agreement No. 14.604.21.0181 of 26.09.2017).

scholarly journals Testing Todd: family types and development

2021 ◽  
pp. 1-18
Author(s):  
Jerg Gutmann ◽  
Stefan Voigt
Keyword(s):  
Rule Of Law ◽  
Civil Society Organizations ◽  
The Rule Of Law ◽  
State Fragility ◽  
Family Types ◽  
Low Levels ◽  
Parsimonious Model ◽  
The One ◽  
High Level

Abstract Many years ago, Emmanuel Todd came up with a classification of family types and argued that the historically prevalent family types in a society have important consequences for its economic, political, and social development. Here, we evaluate Todd's most important predictions empirically. Relying on a parsimonious model with exogenous covariates, we find mixed results. On the one hand, authoritarian family types are, in stark contrast to Todd's predictions, associated with increased levels of the rule of law and innovation. On the other hand, and in line with Todd's expectations, communitarian family types are linked to racism, low levels of the rule of law, and late industrialization. Countries in which endogamy is frequently practiced also display an expectedly high level of state fragility and weak civil society organizations.

scholarly journals Selective Cytotoxicity of Piperine over Multidrug Resistance Leukemic Cells

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 934
Author(s):  
Julia Quarti ◽  
Daianne N. M. Torres ◽  
Erika Ferreira ◽  
Raphael S. Vidal ◽  
Fabiana Casanova ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Black Pepper ◽  
Leukemic Cells ◽  
Glycoprotein P ◽  
Cytotoxic Effects ◽  
Collateral Sensitivity ◽  
Main Challenge ◽  
Independent Mechanism ◽  
High Level ◽  
Parp 1

Multidrug resistance (MDR) is the main challenge in the treatment of chronic myeloid leukemia (CML), and P-glycoprotein (P-gp) overexpression is an important mechanism involved in this resistance process. However, some compounds can selectively affect MDR cells, inducing collateral sensitivity (CS), which may be dependent on P-gp. The aim of this study was to investigate the effect of piperine, a phytochemical from black pepper, on CS induction in CML MDR cells, and the mechanisms involved. The results indicate that piperine induced CS, being more cytotoxic to K562-derived MDR cells (Lucena-1 and FEPS) than to K562, the parental CML cell. CS was confirmed by analysis of cell metabolic activity and viability, cell morphology and apoptosis. P-gp was partially required for CS induction. To investigate a P-gp independent mechanism, we analyzed the possibility that poly (ADP-ribose) polymerase-1 (PARP-1) could be involved in piperine cytotoxic effects. It was previously shown that only MDR FEPS cells present a high level of 24 kDa fragment of PARP-1, which could protect these cells against cell death. In the present study, piperine was able to decrease the 24 kDa fragment of PARP-1 in MDR FEPS cells. We conclude that piperine targets selectively MDR cells, inducing CS, through a mechanism that might be dependent or not on P-gp.

Effects of Beef Juice on Biofilm Formation by Shiga Toxin–Producing Escherichia coli on Stainless Steel

2020 ◽  
Vol 17 (4) ◽  
pp. 235-242 ◽  
Author(s):  
Zhi Ma ◽  
Kim Stanford ◽  
Xiao M. Bie ◽  
Yan D. Niu ◽  
Tim A. McAllister
Keyword(s):  
Escherichia Coli ◽  
Stainless Steel ◽  
Shiga Toxin ◽  
Biofilm Formation

Flavonoids and UV Photoprotection in Arabidopsis Mutants

2001 ◽  
Vol 56 (9-10) ◽  
pp. 745-754 ◽  
Author(s):  
Ken G Ryan ◽  
Ewald E Swinny ◽  
Chris Winefield ◽  
Kenneth R Markham
Keyword(s):  
Crucial Role ◽  
Hydroxycinnamic Acid ◽  
Ultraviolet B ◽  
Uvb Radiation ◽  
Wild Type ◽  
Hydroxycinnamic Acid Derivatives ◽  
Quercetin Glycosides ◽  
Kaempferol Glycosides ◽  
Low Levels ◽  
High Level

AbstractWild-type Arabidopsis L. leaves exposed to low ultraviolet-B (U V B ) conditions contained predominantly kaempferol glycosides, with low levels of quercetin glycosides. The flavonoid level doubled on treatment with UVB and an increase in the ratio of quercetin: kaempferol was observed. These results suggest that flavonols protect Arabidopsis plants from UVB damage, and indicate that the flavonoid 3’-hydroxylase (F3’H) enzyme, which converts dihydrokaempferol to dihydroquercetin, may play a crucial role. The tt7 mutant lacks this gene and, after treatment with sub-ambient UVB, contained kaempferol glycosides exclusively, to a level of total flavonols similar to that in wild-type Arabidopsis. Total flavonols after enhanced UVB treatment were higher in tt7 than in similarly treated wild-type plants, and only kaempferol glycosides were detected. Despite this high level, tt7 plants were less tolerant of UVB radiation than wild-type plants. These observations suggests that kaempferol is a less effective photoprotectant than quercetin. The chalcone isomerase (CHI) mutant (tt5) surprisingly did not accumulate naringenin chalcone, and this suggests that the mutation may not be restricted to the CHI gene alone. The concentration of hydroxycinnamic acid derivatives did not change with UVB treatment in most varieties indicating that their role in UV photoprotection may be subordinate to that of the flavonoids.

scholarly journals Antioxidants, Phytochemicals, and Cytotoxicity Studies onPhaleria macrocarpa(Scheff.) Boerl Seeds

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Ma Ma Lay ◽  
Saiful Anuar Karsani ◽  
Behrooz Banisalam ◽  
Sadegh Mohajer ◽  
Sri Nurestri Abd Malek
Keyword(s):  
Human Cancer ◽  
Cytotoxic Effects ◽  
Nutritional Values ◽  
Water Fraction ◽  
Human Cancer Cells ◽  
Fiber Protein ◽  
Cytotoxicity Studies ◽  
Normal Human ◽  
Lung Cell Line ◽  
Mcf 7

In recent years, the utilization of certain medicinal plants as therapeutic agents has drastically increased.Phaleria macrocarpa(Scheff.) Boerl is frequently used in traditional medicine. The present investigation was undertaken with the purpose of developing pharmacopoeial standards for this species. Nutritional values such as ash, fiber, protein, fat, and carbohydrate contents were investigated, and phytochemical screenings with different reagents showed the presence of flavonoids, glycosides, saponin glycosides, phenolic compounds, steroids, tannins, and terpenoids. Our results also revealed that the water fraction had the highest antioxidant activity compared to the methanol extract and other fractions. The methanol and the fractionated extracts (hexane, chloroform, ethyl acetate, and water) ofP. macrocarpaseeds were also investigated for their cytotoxic effects on selected human cancer cells lines (MCF-7, HT-29, MDA-MB231, Ca Ski, and SKOV-3) and a normal human fibroblast lung cell line (MRC-5). Information from this study can be applied for future pharmacological and therapeutic evaluations of the species, and may assist in the standardization for quality, purity, and sample identification. To the best of our knowledge, this is the first report on the phytochemical screening and cytotoxic effect of the crude and fractionated extracts ofP. macrocarpaseeds on selected cells lines.

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