scholarly journals Life without Division: Physiology ofEscherichia coliFtsZ-Deprived Filaments

mBio ◽  
2016 ◽  
Vol 7 (5) ◽  
Author(s):  
Alicia Sánchez-Gorostiaga ◽  
Pilar Palacios ◽  
Rocío Martínez-Arteaga ◽  
Manuel Sánchez ◽  
Mercedes Casanova ◽  
...  
Keyword(s):  
Solid Medium ◽  
Membrane Integrity ◽  
Test Tube ◽  
Antimicrobial Compounds ◽  
Liquid Form ◽  
Altered Expression ◽  
E Coli ◽  
Ftsz Ring ◽  
Altered Expression Pattern ◽  
The Stability

ABSTRACTWhen deprived of FtsZ,Escherichia colicells (VIP205) grown in liquid form long nonseptated filaments due to their inability to assemble an FtsZ ring and their failure to recruit subsequent divisome components. These filaments fail to produce colonies on solid medium, in which synthesis of FtsZ is induced, upon being diluted by a factor greater than 4. However, once the initial FtsZ levels are recovered in liquid culture, they resume division, and their plating efficiency returns to normal. The potential septation sites generated in the FtsZ-deprived filaments are not annihilated, and once sufficient FtsZ is accumulated, they all become active and divide to produce cells of normal length. FtsZ-deprived cells accumulate defects in their physiology, including an abnormally high number of unsegregated nucleoids that may result from the misplacement of FtsK. Their membrane integrity becomes compromised and the amount of membrane proteins, such as FtsK and ZipA, increases. FtsZ-deprived cells also show an altered expression pattern, namely, transcription of several genes responding to DNA damage increases, whereas transcription of some ribosomal or global transcriptional regulators decreases. We propose that the changes caused by the depletion of FtsZ, besides stopping division, weaken the cell, diminishing its resiliency to minor challenges, such as dilution stress.IMPORTANCEOur results suggest a role for FtsZ, in addition to its already known effect in the constriction ofE. coli, in protecting the nondividing cells against minor stress. This protection can even be exerted when an inactive FtsZ is produced, but it is lost when the protein is altogether absent. These results have implications in fields like synthetic biology or antimicrobial discovery. The construction of synthetic divisomes in the test tube may need to preserve unsuspected roles, such as this newly found FtsZ property, to guarantee the stability of artificial containers. Whereas the effects on viability caused by inhibiting the activity of FtsZ may be partly overcome by filamentation, the absence of FtsZ is not tolerated byE. coli, an observation that may help in the design of effective antimicrobial compounds.

scholarly journals In vitro activity of antimicrobial peptide CDP-B11 alone and in combination with colistin against colistin-resistant and multidrug-resistant Escherichia coli

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kaitlin S. Witherell ◽  
Jason Price ◽  
Ashok D. Bandaranayake ◽  
James Olson ◽  
Douglas R. Call
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Peptide ◽  
Membrane Integrity ◽  
Antibiotic Resistance Genes ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Multidrug Resistant Bacteria ◽  
E Coli ◽  
Minimal Media

AbstractMultidrug-resistant bacteria are a growing global concern, and with increasingly prevalent resistance to last line antibiotics such as colistin, it is imperative that alternative treatment options are identified. Herein we investigated the mechanism of action of a novel antimicrobial peptide (CDP-B11) and its effectiveness against multidrug-resistant bacteria including Escherichia coli #0346, which harbors multiple antibiotic-resistance genes, including mobilized colistin resistance gene (mcr-1). Bacterial membrane potential and membrane integrity assays, measured by flow cytometry, were used to test membrane disruption. Bacterial growth inhibition assays and time to kill assays measured the effectiveness of CDP-B11 alone and in combination with colistin against E. coli #0346 and other bacteria. Hemolysis assays were used to quantify the hemolytic effects of CDP-B11 alone and in combination with colistin. Findings show CDP-B11 disrupts the outer membrane of E. coli #0346. CDP-B11 with colistin inhibits the growth of E. coli #0346 at ≥ 10× lower colistin concentrations compared to colistin alone in Mueller–Hinton media and M9 media. Growth is significantly inhibited in other clinically relevant strains, such as Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae. In rich media and minimal media, the drug combination kills bacteria at a lower colistin concentration (1.25 μg/mL) compared to colistin alone (2.5 μg/mL). In minimal media, the combination is bactericidal with killing accelerated by up to 2 h compared to colistin alone. Importantly, no significant red blood hemolysis is evident for CDP-B11 alone or in combination with colistin. The characteristics of CDP-B11 presented here indicate that it can be used as a potential monotherapy or as combination therapy with colistin for the treatment of multidrug-resistant infections, including colistin-resistant infections.

scholarly journals Modulation of IGF2 Expression in the Murine Thymus and Thymic Epithelial Cells Following Coxsackievirus-B4 Infection

2021 ◽  
Vol 9 (2) ◽  
pp. 402
Author(s):  
Hélène Michaux ◽  
Aymen Halouani ◽  
Charlotte Trussart ◽  
Chantal Renard ◽  
Hela Jaïdane ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Cell Line ◽  
Thymic Epithelial Cells ◽  
Altered Expression ◽  
Coxsackievirus B4 ◽  
Gene Coding ◽  
Self Tolerance ◽  
Stat3 Phosphorylation ◽  
The Stability

Coxsackievirus B4 (CV-B4) can infect human and murine thymic epithelial cells (TECs). In a murine TEC cell line, CV-B4 can downregulate the transcription of the insulin-like growth factor 2 (Igf2) gene coding for the self-peptide of the insulin family. In this study, we show that CV-B4 infections of a murine TEC cell line decreased Igf2 P3 promoter activity by targeting a region near the transcription start site; however, the stability of Igf2 transcripts remained unchanged, indicating a regulation of Igf2 transcription. Furthermore, CV-B4 infections decreased STAT3 phosphorylation in vitro. We also showed that mice infected with CV-B4 had an altered expression of Igf2 isoforms as detected in TECs, followed by a decrease in the pro-IGF2 precursor in the thymus. Our study sheds new light on the intrathymic regulation of Igf2 transcription during CV-B4 infections and supports the hypothesis that a viral infection can disrupt central self-tolerance to insulin by decreasing Igf2 transcription in the thymic epithelium.

Altered Expression Pattern of Acid-Sensing Ion Channel Isoforms in Piriform Cortex After Seizures

2015 ◽  
Vol 53 (3) ◽  
pp. 1782-1793 ◽  
Author(s):  
Hao Wu ◽  
Chao Wang ◽  
Bei Liu ◽  
Huanfa Li ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Ion Channel ◽  
Expression Pattern ◽  
Piriform Cortex ◽  
Altered Expression ◽  
Altered Expression Pattern

scholarly journals Altered expression pattern of testican-1 mRNA after brain injury

2011 ◽  
Vol 32 (6) ◽  
pp. 373-378 ◽  
Author(s):  
Ken Iseki ◽  
Seita Hagino ◽  
Yuxiang Zhang ◽  
Tetsuji Mori ◽  
Nobuko Sato ◽  
...  
Keyword(s):  
Brain Injury ◽  
Expression Pattern ◽  
Altered Expression ◽  
Altered Expression Pattern

scholarly journals Bactericidal and virucidal efficacies of food additive grade calcium hydroxide under various concentrations, organic material conditions, exposure duration, and its stability

2019 ◽  
Vol 12 (9) ◽  
pp. 1383-1389
Author(s):  
Sakchai Ruenphet ◽  
Kornkamon Paditporn ◽  
Darsaniya Punyadarsaniya ◽  
Tippawan Jantafong ◽  
Kazuaki Takehara
Keyword(s):  
Calcium Hydroxide ◽  
Organic Material ◽  
Exposure Duration ◽  
Organic Materials ◽  
Exposure Period ◽  
Food Additive ◽  
E Coli ◽  
Dry Conditions ◽  
Material Conditions ◽  
The Stability

Aim: This study aimed to evaluate the bactericidal and virucidal activity of food additive grade calcium hydroxide (FdCa(OH)2) under various concentrations, organic material conditions, and exposure duration including its stability. Materials and Methods: The FdCa(OH)2 powder as well as the 0.17% and 3% solutions were evaluated for bacteria and virus inactivating efficacies against Salmonella infantis (SI), Escherichia coli, Newcastle disease virus (NDV), and avian influenza virus (AIV), in the absence or presence of organic materials. In addition, the stability of FdCa(OH)2, was also examined using wet-dry conditions and under sunlight. Results: The FdCa(OH)2 powder could inactivate both NDV and AIV in the absence and presence of organic materials within a 3 min exposure period. The bactericidal efficacy using solution form revealed that 0.17% and 3% of FdCa(OH)2 could inactivate SI in the absence and presence of organic materials within 3 min of exposure. However, 3% of FdCa(OH)2 inactivated E. coli both with and without organic materials within 3min, while 0.17% required 5 min to be efficacious. The virucidal efficacy also showed that 0.17% FdCa(OH)2 could inactivate NDV in the absence and presence of organic materials within 10 min and 30 min, respectively. However, AIV inactivation was achieved within 30 sec under all conditions. In addition, under wet and dry conditions, FdCa(OH)2 powder demonstrated high efficacy when re-suspended at least 16 times for NDV and 7 times for AIV. Simultaneously, the FdCa(OH)2 powder retained its efficacy under the sunlight during up to 4 months for NDV and at least 6 months for AIV. Conclusion: The present study indicates that FdCa(OH)2 powder and solutions could inactivate SI, E. coli, NDV, and AIV while retaining good stability under challenging environmental conditions. Finally, the FdCa(OH)2 is safe for consumers because it is of food additive grade and can be useful as an alternative disinfectant, especially for biosecurity enhancement on and around poultry farms.

scholarly journals Effect of Essential Oils on Growth Inhibition, Biofilm Formation and Membrane Integrity of Escherichia coli and Staphylococcus aureus

Antibiotics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1474
Author(s):  
Andrés Martínez ◽  
Marcela Manrique-Moreno ◽  
Maria C. Klaiss-Luna ◽  
Elena Stashenko ◽  
German Zafra ◽  
...  
Keyword(s):  
Essential Oils ◽  
Lipid Bilayers ◽  
Biofilm Formation ◽  
Method Development ◽  
Membrane Integrity ◽  
Thymus Vulgaris ◽  
Hydrophobic Core ◽  
Synthetic Membranes ◽  
E Coli ◽  
Microdilution Method

Biofilm as a cellular conformation confers survival properties to microbial populations and favors microbial resistance. Here, we investigated the antimicrobial, antibiofilm, antimotility, antihemolytic activity, and the interaction with synthetic membranes of 15 essential oils (EOs) on E. coli ATCC 25922 and S. aureus ATCC 29213. Antimicrobial activity of EOs was determined through microdilution method; development of the biofilm was assessed using the crystal violet assay and SEM microscopy. Results indicate that Lippia origanoides thymol–carvacrol II chemotype (LTC II) and Thymus vulgaris (TV) exhibited a significant antibacterial activity, with MIC values of 0.45 and 0.75 mg/mL, respectively. The percentage of biofilm formation inhibition was greater than 70% at subinhibitory concentrations (MIC50) for LTC II EO. The results demonstrate that these two oils had significantly reduced the hemolytic effect of S. aureus by 54% and 32%, respectively, and the mobility capacity by swimming in E. coli with percentages of decrease of 55% and 47%, respectively. The results show that LTC II and TV EOs can interact with the hydrophobic core of lipid bilayers and alter the physicochemical properties of membranes. The findings suggest that LTC II and TV oils may potentially be used to aid in the treatment of S. aureus and E. coli infections.

scholarly journals Bacterial exposure leads to variable mortality but not a measurable increase in surface antimicrobials across ant species

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10412
Author(s):  
Omar Halawani ◽  
Robert R. Dunn ◽  
Amy M. Grunden ◽  
Adrian A. Smith
Keyword(s):  
Staphylococcus Epidermidis ◽  
Solenopsis Invicta ◽  
Antimicrobial Compounds ◽  
Inhibitory Effects ◽  
E Coli ◽  
Aphaenogaster Rudis ◽  
Wide Range ◽  
Health Threats ◽  
Environmental Bacteria ◽  
Significant Mortality

Social insects have co-existed with microbial species for millions of years and have evolved a diversity of collective defenses, including the use of antimicrobials. While many studies have revealed strategies that ants use against microbial entomopathogens, and several have shown ant-produced compounds inhibit environmental bacterial growth, few studies have tested whether exposure to environmental bacteria represents a health threat to ants. We compare four ant species’ responses to exposure to Escherichia coli and Staphylococcus epidermidis bacteria in order to broaden our understanding of microbial health-threats to ants and their ability to defend against them. In a first experiment, we measure worker mortality of Solenopsis invicta, Brachymyrmex chinensis, Aphaenogaster rudis, and Dorymyrmex bureni in response to exposure to E. coli and S. epidermidis. We found that exposure to E. coli was lethal for S. invicta and D. bureni, while all other effects of exposure were not different from experimental controls. In a second experiment, we compared the antimicrobial ability of surface extracts from bacteria-exposed and non-exposed S. invicta and B. chinensis worker ants, to see if exposure to E. coli or S. epidermidis led to an increase in antimicrobial compounds. We found no difference in the inhibitory effects from either treatment group in either species. Our results demonstrate the susceptibility to bacteria is varied across ant species. This variation may correlate with an ant species’ use of surface antimicrobials, as we found significant mortality effects in species which also were producing antimicrobials. Further exploration of a wide range of both bacteria and ant species is likely to reveal unique and nuanced antimicrobial strategies and deepen our understanding of how ant societies respond to microbial health threats.

scholarly journals In Vitro and In Vivo Assessment of the Potential of Escherichia coli Phages to Treat Infections and Survive Gastric Conditions

2021 ◽  
Vol 9 (9) ◽  
pp. 1869
Author(s):  
Joanna Kaczorowska ◽  
Eoghan Casey ◽  
Gabriele A. Lugli ◽  
Marco Ventura ◽  
David J. Clarke ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Galleria Mellonella ◽  
Enterotoxigenic Escherichia Coli ◽  
E Coli ◽  
Composite Mixture ◽  
Ph Conditions ◽  
The Stability ◽  
Higher Sensitivity

Enterotoxigenic Escherichia coli (ETEC) and Shigella ssp. infections are associated with high rates of mortality, especially in infants in developing countries. Due to increasing levels of global antibiotic resistance exhibited by many pathogenic organisms, alternative strategies to combat such infections are urgently required. In this study, we evaluated the stability of five coliphages (four Myoviridae and one Siphoviridae phage) over a range of pH conditions and in simulated gastric conditions. The Myoviridae phages were stable across the range of pH 2 to 7, while the Siphoviridae phage, JK16, exhibited higher sensitivity to low pH. A composite mixture of these five phages was tested in vivo in a Galleria mellonella model. The obtained data clearly shows potential in treating E. coli infections prophylactically.

Interaction specificity between the chaperone and proteolytic components of the cyanobacterial Clp protease

2012 ◽  
Vol 446 (2) ◽  
pp. 311-320 ◽  
Author(s):  
Anders Tryggvesson ◽  
Frida M. Ståhlberg ◽  
Axel Mogk ◽  
Kornelius Zeth ◽  
Adrian K. Clarke
Keyword(s):  
Escherichia Coli ◽  
Active Sites ◽  
Terminal Sequence ◽  
Core Complex ◽  
Clp Protease ◽  
E Coli ◽  
Loop Region ◽  
N Terminus ◽  
Specific Association ◽  
The Stability

The Clp protease is conserved among eubacteria and most eukaryotes, and uses ATP to drive protein substrate unfolding and translocation into a chamber of sequestered proteolytic active sites. In plant chloroplasts and cyanobacteria, the essential constitutive Clp protease consists of the Hsp100/ClpC chaperone partnering a proteolytic core of catalytic ClpP and noncatalytic ClpR subunits. In the present study, we have examined putative determinants conferring the highly specific association between ClpC and the ClpP3/R core from the model cyanobacterium Synechococcus elongatus. Two conserved sequences in the N-terminus of ClpR (tyrosine and proline motifs) and one in the N-terminus of ClpP3 (MPIG motif) were identified as being crucial for the ClpC–ClpP3/R association. These N-terminal domains also influence the stability of the ClpP3/R core complex itself. A unique C-terminal sequence was also found in plant and cyanobacterial ClpC orthologues just downstream of the P-loop region previously shown in Escherichia coli to be important for Hsp100 association to ClpP. This R motif in Synechococcus ClpC confers specificity for the ClpP3/R core and prevents association with E. coli ClpP; its removal from ClpC reverses this core specificity.

scholarly journals Antibiofilm Activity of an Experimental Ricinus Communis Dentifrice on Soft Denture Liners

2019 ◽  
Vol 30 (3) ◽  
pp. 252-258 ◽  
Author(s):  
Maurício Malheiros Badaró ◽  
Vanessa Maria Fagundes Leite-Fernandes ◽  
Luciano Trevisan Martin ◽  
Viviane de Cássia Oliveira ◽  
Evandro Watanabe ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Culture Medium ◽  
Solid Medium ◽  
Ricinus Communis ◽  
Positive Control ◽  
Antibiofilm Activity ◽  
Candida Spp ◽  
E Coli ◽  
Liquid Culture Medium ◽  
Denture Liners

Abstract The disadvantage of liners materials is the difficulty of biofilm control. It was compared an experimental dentifrice contained Ricinus communis, with commercials dentifrices as antibiofilm activity against microorganisms on denture liner. Six hundred specimens were distributed in 5 groups (n=18/ microorganism): water; experimental dentifrice; specific dentifrice for denture and two conventional dentifrices against C. albicans; C. glabrata; S. mutans; S. aureus; E. coli. Each group had a negative (n=5; without contamination) and positive control (n=15/ microorganism; without cleaning). The antibiofilm activity was evaluated by the method of biofilm formation in triplicate. The specimens were contaminated in a standard way and incubated. After that, manual brushing was performed (60 s), washed with PBS, immersed in liquid culture medium for resuspension and sowing in solid medium. The results (mean of triplicates) were expressed in CFU/mL. The data was submitted to Shapiro-Wilk, ANOVA and Tukey test (p<0.05). The specific dentifrice (1.27±1.20) was the most effective against S. mutans, followed by conventional (Trihydral, 3.13±0.88; Colgate, 2.16±2.02) and experimental (3.81±1.37) dentifrices, which were similar to each other (p=0.008). All of them were different from water (4.79±1.42). The specific (0.21±0.21) and experimental (0.36±0.25) dentifrices were similar against S. aureus, with a higher mean of CFU when compared to conventional (Colgate, 0.06±0.13), which was more efficient (p=0.000). For C. albicans, C. glabrata and E. coli, all dentifrices were similar to water (p=0.186). It was concluded, that the experimental dentifrice was effective against S. aureus and had not efficacy against Candida spp.; S. mutans; E. coli, as occurred with the commercials dentifrices.

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