The in vitro Synergistic Inhibitory Effect of Human Amniotic Fluid and Gentamicin on Growth of Escherichia coli

Chemotherapy ◽  
1996 ◽  
Vol 42 (3) ◽  
pp. 206-209 ◽  
Author(s):  
P.A. Miglioli ◽  
U. Schoffel ◽  
L. Gianfranceschi
Keyword(s):  
Escherichia Coli ◽  
Amniotic Fluid ◽  
Inhibitory Effect ◽  
Human Amniotic Fluid ◽  
Synergistic Inhibitory Effect

scholarly journals Genome-Wide fitness analysis of group B Streptococcus in human amniotic fluid reveals a transcription factor that controls multiple virulence traits

2021 ◽  
Vol 17 (3) ◽  
pp. e1009116
Author(s):  
Allison N. Dammann ◽  
Anna B. Chamby ◽  
Andrew J. Catomeris ◽  
Kyle M. Davidson ◽  
Hervé Tettelin ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Amniotic Fluid ◽  
Deletion Strain ◽  
Growth Defect ◽  
Wild Type ◽  
Human Amniotic Fluid ◽  
Wide Range ◽  
Pregnant Mice ◽  
Group B

Streptococcus agalactiae (group B Streptococcus; GBS) remains a dominant cause of serious neonatal infections. One aspect of GBS that renders it particularly virulent during the perinatal period is its ability to invade the chorioamniotic membranes and persist in amniotic fluid, which is nutritionally deplete and rich in fetal immunologic factors such as antimicrobial peptides. We used next-generation sequencing of transposon-genome junctions (Tn-seq) to identify five GBS genes that promote survival in the presence of human amniotic fluid. We confirmed our Tn-seq findings using a novel CRISPR inhibition (CRISPRi) gene expression knockdown system. This analysis showed that one gene, which encodes a GntR-class transcription factor that we named MrvR, conferred a significant fitness benefit to GBS in amniotic fluid. We generated an isogenic targeted deletion of the mrvR gene, which had a growth defect in amniotic fluid relative to the wild type parent strain. The mrvR deletion strain also showed a significant biofilm defect in vitro. Subsequent in vivo studies showed that while the mutant was able to cause persistent murine vaginal colonization, pregnant mice colonized with the mrvR deletion strain did not develop preterm labor despite consistent GBS invasion of the uterus and the fetoplacental units. In contrast, pregnant mice colonized with wild type GBS consistently deliver prematurely. In a sepsis model the mrvR deletion strain showed significantly decreased lethality. In order to better understand the mechanism by which this newly identified transcription factor controls GBS virulence, we performed RNA-seq on wild type and mrvR deletion GBS strains, which revealed that the transcription factor affects expression of a wide range of genes across the GBS chromosome. Nucleotide biosynthesis and salvage pathways were highly represented among the set of differentially expressed genes, suggesting that MrvR may be involved in regulating nucleotide availability.

scholarly journals Antibacterial and Antifungal Capacity of Three Commercially Available Mouthwashes with Different Concentrations of Chlorhexidine

2021 ◽  
pp. 380-391
Author(s):  
Daniel Chavarría-Bolaños ◽  
Vicente Esparza-Villalpando ◽  
Karol Ramírez
Keyword(s):  
Escherichia Coli ◽  
Dental Plaque ◽  
Inhibitory Effect ◽  
Low Doses ◽  
Antifungal Effect ◽  
Antibacterial And Antifungal ◽  
Antiseptic Solutions ◽  
Antifungal Efficacy ◽  
Support Evidence

Chlorhexidine was introduced almost seven decades ago and has a myriad of applications in dentistry. Few studies have evaluated the antimicrobial and antifungal capacity of different concentrations of chlorhexidine mouthwashes. Therefore, the aim of this study, was to evaluate in vitro, the antibacterial and antifungal capacity of three commercially available mouthwashes in Costa Rica, with different concentrations of chlorhexidine, 0.12%, 0.06%, and 0.03%. The experimental method selected was the Kirby-Bauer method to evaluate the antibacterial and antifungal effect of each compound by measuring the inhibitory effect on Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Candida albicans strains, exposed to the antiseptic solutions. All samples showed some degree of antibacterial and antifungal effect. Even though we provide in vitro results, our findings are of relevance since all the species used in our experiment are microorganisms that may be present in dental plaque. Our results further support evidence that oral hygiene regimens may include mouthwashes with low doses of chlorhexidine and maintain reasonable antibacterial and antifungal efficacy.

In vitro survival of Listeria monocytogenes in human amniotic fluid

1999 ◽  
Vol 202 (5) ◽  
pp. 377-382 ◽  
Author(s):  
Clelia Altieri ◽  
Giuseppe Maruotti ◽  
Costanzo Natale ◽  
Salvatore Massa
Keyword(s):  
Listeria Monocytogenes ◽  
Amniotic Fluid ◽  
Human Amniotic Fluid ◽  
In Vitro Survival

G-CSF and Erythropoietin Stability in Amniotic Fluid during Simulated in vitro Digestion Conditions

2002 ◽  
Vol 18 (6) ◽  
pp. 310-315 ◽  
Author(s):  
Darlene A Calhoun ◽  
Brooke E Richards ◽  
Jason A Gersting ◽  
Sandra E Sullivan ◽  
Robert D Christensen
Keyword(s):  
Amniotic Fluid ◽  
Preterm Neonate ◽  
In Vitro Digestion ◽  
Human Amniotic Fluid ◽  
Time Zero ◽  
Simulated Digestion ◽  
The Stability ◽  
Stimulating Factor ◽  
Degree Of Degradation

Objective: To determine the stability of granulocyte colony-stimulating factor (G-CSF) and erythropoietin (Epo) in human amniotic fluid and recombinant G-CSF (Neupogen) and Epo (Epogen) in simulated amniotic fluid to digestions at pH concentrations of 3.2, 4.5, and 5.8 to assess their bioavailability to the neonate. Design: A simulated amniotic fluid containing Neupogen and Epogen was subjected to in vitro conditions that mimicked preprandial and postprandial neonatal intestinal digestion. Human amniotic fluid was tested using identical digestion conditions as well as human amniotic fluid to which Epogen and Neupogen had been added. Main Outcome Measures: The percentages of G-CSF/Epo and Neupogen/Epogen remaining after 1 and 2 hours of simulated digestions were compared with those at time zero, and concentrations at 2 hours were compared with those at 1 hour and time zero. Results: In simulated amniotic fluid at pH 3.2, significant degradation of G-CSF was observed at 1 hour (p = 0.03). No differences were observed at 1 or 2 hours for either pH 4.5 (p = 0.30 and 0.11, respectively) or pH 5.8 (p = 0.20 and 0.49, respectively). Human amniotic fluid exhibited significant degradation pH 3.2 (p = 0.04) and pH 4.5 (p < 0.05) at 1 hour; no difference was noted at pH 5.8 at 1 hour (p = 0.34). When additional Neupogen was added to human amniotic fluid, significant degradation was observed at pH 3.2 (p < 0.05) and pH 4.5 (p = 0.03) at 1 hour; no difference was noted at 1 hour at pH 5.8 (p = 0.11). In simulated amniotic fluid at pH 3.2, significant degradation of Epo occurred at 1 hour (p < 0.05). There were no differences at 1 hour for pH 4.5 (p = 0.50) or pH 5.8 (p = 0.17). Human amniotic fluid exhibited significant degradation at pH 3.2 (p < 0.05) and pH 4.5 (p < 0.05) at 1 hour; no difference was noted at 1 hour at pH 5.8 (p = 0.34). When additional Epogen was added to human amniotic fluid, significant degradation was observed at pH 3.2 (p = 0.001) and pH 4.5 (p = 0.003); no difference was noted at 1 hour at pH 5.8 (p = 0.31). Conclusions: G-CSF/Epo in human amniotic fluid and Neupogen/Epogen in simulated amniotic fluid are preserved to varying degrees during simulated digestion conditions. The degree of degradation of both cytokines was time- and pH-dependent. Measurable quantities of G-CSF and Epo are biologically available when swallowed by the fetus or a preterm neonate.

Lactobacillus inhibitor production against Escherichia coli and coaggregation ability with uropathogens

1988 ◽  
Vol 34 (3) ◽  
pp. 344-351 ◽  
Author(s):  
Gregor Reid ◽  
Jacqueline A. McGroarty ◽  
Rosanne Angotti ◽  
Roger L. Cook
Keyword(s):  
Escherichia Coli ◽  
Defense Mechanism ◽  
Inhibitory Effect ◽  
Second Phase ◽  
Vitro Assay ◽  
E Coli ◽  
Host Defense Mechanism ◽  
Important Host ◽  
Two Phases

Previous investigations have shown that certain strains of lactobacilli can competitively exclude uropathogens from attaching to uroepithelial cells and from causing urinary tract infection in animals. The finding of an inhibitory effect produced by Lactobacillus casei ssp. rhamnosus GR-1 against the growth of uropathogens was investigated further using two Escherichia coli indicator strains Hu 734 and ATCC 25922. There were two phases to the inhibitor studies. The first one using an agar sandwich technique showed that the inhibitor activity was heat stable and inhibitory to the E. coli. The second phase showed that MRS broth provided optimum lactobacilli growth and inhibitor production. In addition, the inhibition was present under conditions buffering for acid and pH. The data indicated that the inhibitory effect was not due to bacteriophages or hydrogen peroxide. Strain GR-1 was found to coaggregate with E. coli ATCC 25922 in urine, a phenomenon that has not previously been reported for urogenital bacteria. An in vitro assay system was developed to study the coaggregation of various lactobacilli and uropathogens. The results demonstrated that highest coaggregation scores occurred after 4 h incubation at 37 °C with lactobacilli and two type-1 fimbriated E. coli strains. Of the nine lactobacilli strains tested, each was found to coaggregate with 2 or more of the 13 uropathogens. The dominance of inhibitor-producing lactobacilli on the urogenital epithelium and the ability of these organisms to interact closely with uropathogens would constitute an important host defense mechanism against infection.

Ce-Based Nanoparticles Loaded with Cisplatin for Tumour Radiotherapy

2020 ◽  
Vol 16 (10) ◽  
pp. 1482-1494
Author(s):  
Li Sun ◽  
Chang Jiang ◽  
Wenhai Li ◽  
Zelai He ◽  
Gengming Wang ◽  
...  
Keyword(s):  
Photoelectric Effect ◽  
Inhibitory Effect ◽  
Precipitation Method ◽  
Treatment Mode ◽  
X Ray ◽  
Transmission Electron ◽  
Good Biocompatibility ◽  
Synergistic Inhibitory Effect

The combination of radiotherapy and chemotherapy is a common and useful treatment mode for tumours. But traditional methods inevitably lead to a variety of side effects. A drug delivery system (DDS), which has good biocompatibility and strong anti-tumour ability, is expected to solve this problem. Studies have shown that Ce-based nanoparticles (NPs) have good radiosensitization effect through the photoelectric effect. Hence, cisplatin-loaded LiLuF4 :Ce3+scintillation NPs (NP + Cis) were first constructed in this study, which was synthesized by the crystal precipitation method and characterized by transmission electron microscopy (TEM). Subsequently, its toxicity was verified, and the radiosensitization effect and basic radiosensitization mechanism on tumour cells and tumour-bearing mice were researched. Results showed that NP + Cis triggered massive DNA damage and effectively inhibited cell viability in vitro under the exposure of X-ray irradiation (IR). Moreover, the experiments in vivo showed that the NP + Cis had higher biosafety, which could absorb enough irradiation and produce a synergistic inhibitory effect on tumours through the releasing of Cis. NP + Cis can improve the performance of DDS in chemoradiotherapy.

scholarly journals Role of F1C Fimbriae, Flagella, and Secreted Bacterial Components in the Inhibitory Effect of Probiotic Escherichia coli Nissle 1917 on Atypical Enteropathogenic E. coli Infection

2014 ◽  
Vol 82 (5) ◽  
pp. 1801-1812 ◽  
Author(s):  
Sylvia Kleta ◽  
Marcel Nordhoff ◽  
Karsten Tedin ◽  
Lothar H. Wieler ◽  
Rafal Kolenda ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Molecular Mechanisms ◽  
Inhibitory Effect ◽  
Host Cells ◽  
Single Infection ◽  
Content Type ◽  
E Coli ◽  
Initial Adhesion

ABSTRACTEnteropathogenicEscherichia coli(EPEC) is recognized as an important intestinal pathogen that frequently causes acute and persistent diarrhea in humans and animals. The use of probiotic bacteria to prevent diarrhea is gaining increasing interest. The probioticE. colistrain Nissle 1917 (EcN) is known to be effective in the treatment of several gastrointestinal disorders. While bothin vitroandin vivostudies have described strong inhibitory effects of EcN on enteropathogenic bacteria, including pathogenicE. coli, the underlying molecular mechanisms remain largely unknown. In this study, we examined the inhibitory effect of EcN on infections of porcine intestinal epithelial cells with atypical enteropathogenicE. coli(aEPEC) with respect to single infection steps, including adhesion, microcolony formation, and the attaching and effacing phenotype. We show that EcN drastically reduced the infection efficiencies of aEPEC by inhibiting bacterial adhesion and growth of microcolonies, but not the attaching and effacing of adherent bacteria. The inhibitory effect correlated with EcN adhesion capacities and was predominantly mediated by F1C fimbriae, but also by H1 flagella, which served as bridges between EcN cells. Furthermore, EcN seemed to interfere with the initial adhesion of aEPEC to host cells by secretion of inhibitory components. These components do not appear to be specific to EcN, but we propose that the strong adhesion capacities enable EcN to secrete sufficient local concentrations of the inhibitory factors. The results of this study are consistent with a mode of action whereby EcN inhibits secretion of virulence-associated proteins of EPEC, but not their expression.

In vitro differentiation into insulin-producing β-cells of stem cells isolated from human amniotic fluid and dental pulp

2013 ◽  
Vol 45 (8) ◽  
pp. 669-676 ◽  
Author(s):  
Gianluca Carnevale ◽  
Massimo Riccio ◽  
Alessandra Pisciotta ◽  
Francesca Beretti ◽  
Tullia Maraldi ◽  
...  
Keyword(s):  
Stem Cells ◽  
Amniotic Fluid ◽  
Dental Pulp ◽  
In Vitro Differentiation ◽  
Β Cells ◽  
Human Amniotic Fluid

scholarly journals Nuclear Nox4 Role in Stemness Power of Human Amniotic Fluid Stem Cells

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Tullia Maraldi ◽  
Marianna Guida ◽  
Manuela Zavatti ◽  
Elisa Resca ◽  
Laura Bertoni ◽  
...  
Keyword(s):  
Stem Cells ◽  
Transcription Factors ◽  
Amniotic Fluid ◽  
Human Stem Cells ◽  
Human Amniotic Fluid ◽  
Differentiation Potential ◽  
Amniotic Fluid Stem Cells ◽  
Target Molecules ◽  
Cellular Compartments

Human amniotic fluid stem cells (AFSC) are an attractive source for cell therapy due to their multilineage differentiation potential and accessibility advantages. However the clinical application of human stem cells largely depends on their capacity to expandin vitro, since there is an extensive donor-to-donor heterogeneity. Reactive oxygen species (ROS) and cellular oxidative stress are involved in many physiological and pathophysiological processes of stem cells, including pluripotency, proliferation, differentiation, and stress resistance. The mode of action of ROS is also dependent on the localization of their target molecules. Thus, the modifications induced by ROS can be separated depending on the cellular compartments they affect. NAD(P)H oxidase family, particularly Nox4, has been known to produce ROS in the nucleus. In the present study we show that Nox4 nuclear expression (nNox4) depends on the donor and it correlates with the expression of transcription factors involved in stemness regulation, such as Oct4, SSEA-4, and Sox2. Moreover nNox4 is linked with the nuclear localization of redox sensitive transcription factors, as Nrf2 and NF-κB, and with the differentiation potential. Taken together, these results suggest that nNox4 regulation may have important effects in stem cell capability through modulation of transcription factors and DNA damage.

Sign in / Sign up

Export Citation Format

Share Document