scholarly journals Isolation and Characterization of Bacteriophages That Infect Citrobacter rodentium, a Model Pathogen for Intestinal Diseases

Viruses ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 737
Author(s):  
Carolina M. Mizuno ◽  
Tiffany Luong ◽  
Robert Cederstrom ◽  
Mart Krupovic ◽  
Laurent Debarbieux ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Phage Therapy ◽  
Lytic Cycle ◽  
Citrobacter Rodentium ◽  
Low Oxygen ◽  
In Vivo Models ◽  
Isolation And Characterization ◽  
Oxygen Conditions ◽  
Phage Strain

Enteropathogenic Escherichia coli (EPEC) is a major pathogen for diarrheal diseases among children. Antibiotics, when used appropriately, are effective; however, their overuse and misuse have led to the rise of antibiotic resistance worldwide. Thus, there are renewed efforts into the development of phage therapy as an alternative antibacterial therapy. Because EPEC in vivo models have shortcomings, a surrogate is used to study the mouse pathogen Citrobacter rodentium in animal models. In this study, two new phages CrRp3 and CrRp10, which infect C. rodentium, were isolated and characterized. CrRp3 was found to be a new species within the genus Vectrevirus, and CrRp10 is a new strain within the species Escherichia virus Ime09, in the genus Tequatrovirus. Both phages appear to have independently evolved from E. coli phages, rather than other Citrobacter spp. phages. Neither phage strain carries known genes associated with bacterial virulence, antibiotic resistance, or lysogeny. CrRp3 is more potent, having a 24-fold faster adsorption rate and shorter lytic cycle when compared to the same properties of CrRp10. However, a lysis curve analysis revealed that CrRp10 prevented growth of C. rodentium for 18 h, whereas resistance developed against CrRp3 within 9 h. We also show that hypoxic (5% oxygen) conditions decreased CrRp3 ability to control bacterial densities in culture. In contrast, low oxygen conditions did not affect CrRp10 ability to replicate on C. rodentium. Together, CrRp10 is likely to be the better candidate for future phage therapy investigations.

scholarly journals Isolation and characterization of bacteriophages that infect Citrobacter rodentium, a model pathogen for investigating human intestinal diseases

2018 ◽  
Author(s):  
Carolina M. Mizuno ◽  
Tiffany Luong ◽  
Robert Cedarstrom ◽  
Mart Krupovic ◽  
Laurent Debarbieux ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Phage Therapy ◽  
Limit Of Detection ◽  
Lytic Cycle ◽  
Citrobacter Rodentium ◽  
E Coli ◽  
Isolation And Characterization ◽  
A New Species

AbstractEnteropathogenic Escherichia coli (EPEC) is a major etiology for diarrheal diseases among children. Antibiotics, when used appropriately, are effective; however, their overuse and misuse has led to the rise of antibiotic resistance worldwide. Thus, there are renewed efforts into the development of phage therapy. Due to the drawbacks of EPEC in vivo models, a surrogate is the mouse-restricted gut pathgoen Citrobacter rodentium. In this study, two new phages CrRp3 and CrRp10, which infect C. rodentium, were isolated and characterized. CrRp3 was found to be a new species within the genus Vectrevirus and CrRp10 is a new strain within the genus Tequatrovirus. Neither phage carries known genes associated with bacterial virulence, antibiotic resistance, or lysogeny. CrRp3 and CrRp10 appear to have independently evolved from E. coli phages. CrRp3 appears to be the more ‘potent’ being 24x more likely to find a host cell and has a shorter lytic cycle, while CrRp10 at MOI 0.001 was able to maintain bacterial density below the limit of detection after 18 h. We found that hypoxia (5% O2 and 5% CO2) inhibited CrRp3 ability to reverse exponential bacterial growth. It is unclear whether the subtle characteristic differences between CrRp3 and CrRp10 will influence treatment efficacy in future phage therapy in vivo investigations.

scholarly journals Antibiotics Act with vB_AbaP_AGC01 Phage against Acinetobacter baumannii in Human Heat-Inactivated Plasma Blood and Galleria mellonella Models

2020 ◽  
Vol 21 (12) ◽  
pp. 4390
Author(s):  
Bartłomiej Grygorcewicz ◽  
Marta Roszak ◽  
Piotr Golec ◽  
Daria Śleboda-Taront ◽  
Natalia Łubowska ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Phage Therapy ◽  
Galleria Mellonella ◽  
Ex Vivo ◽  
Bacterial Species ◽  
Larval Survival ◽  
Broad Host Range ◽  
Phenotypic Analysis ◽  
In Vivo Models

Increasing multidrug resistance has led to renewed interest in phage-based therapy. A combination of the bacteriophages and antibiotics presents a promising approach enhancing the phage therapy effectiveness. First, phage candidates for therapy should be deeply characterized. Here we characterize the bacteriophage vB_AbaP_AGC01 that poses antibacterial activity against clinical Acinetobacter baumannii strains. Moreover, besides genomic and phenotypic analysis our study aims to analyze phage–antibiotic combination effectiveness with the use of ex vivo and in vivo models. The phage AGC01 efficiently adsorbs to A. baumannii cells and possesses a bacteriolytic lifecycle resulting in high production of progeny phages (317 ± 20 PFU × cell−1). The broad host range (50.27%, 93 out of 185 strains) against A. baumannii isolates and the inability of AGC01 to infect other bacterial species show its high specificity. Genomic analysis revealed a high similarity of the AGC01 genome sequence with that of the Friunavirus genus from a subfamily of Autographivirinae. The AGC01 is able to significantly reduce the A. baumannii cell count in a human heat-inactivated plasma blood model (HIP-B), both alone and in combination with antibiotics (gentamicin (GEN), ciprofloxacin (CIP), and meropenem (MER)). The synergistic action was observed when a combination of phage treatment with CIP or MER was used. The antimicrobial activity of AGC01 and phage-antibiotic combinations was confirmed using an in vivo larva model. This study shows the greatest increase in survival of G. mellonella larvae when the combination of phage (MOI = 1) and MER was used, which increased larval survival from 35% to 77%. Hence, AGC01 represents a novel candidate for phage therapy. Additionally, our study suggests that phages and antibiotics can act synergistically for greater antimicrobial effect when used as combination therapy.

Isolation and Characterization of Bacteria Capable of Degrading Phenol and Reducing Nitrate Under Low-Oxygen Conditions

2003 ◽  
Vol 47 (6) ◽  
Author(s):  
Seung-Hun Baek ◽  
Kyoung-Ho Kim ◽  
Cheng-Ri Yin ◽  
Che Ok Jeon ◽  
Wan-Taek Im ◽  
...  
Keyword(s):  
Low Oxygen ◽  
Isolation And Characterization ◽  
Oxygen Conditions

scholarly journals Transfer of Antibiotic Resistance Marker Genes between Lactic Acid Bacteria in Model Rumen and Plant Environments

2009 ◽  
Vol 75 (10) ◽  
pp. 3146-3152 ◽  
Author(s):  
Niamh Toomey ◽  
�ine Monaghan ◽  
S�amus Fanning ◽  
Declan Bolton
Keyword(s):  
Antibiotic Resistance ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Marker Genes ◽  
Natural Environments ◽  
In Vivo Models ◽  
Filter Mating ◽  
Mating Method

ABSTRACT Three wild-type dairy isolates of lactic acid bacteria (LAB) and one Lactococcus lactis control strain were analyzed for their ability to transfer antibiotic resistance determinants (plasmid or transposon located) to two LAB recipients using both in vitro methods and in vivo models. In vitro transfer experiments were carried out with the donors and recipients using the filter mating method. In vivo mating examined transfer in two natural environments, a rumen model and an alfalfa sprout model. All transconjugants were confirmed by Etest, PCR, pulsed-field gel electrophoresis, and Southern blotting. The in vitro filter mating method demonstrated high transfer frequencies between all LAB pairs, ranging from 1.8 � 10−5 to 2.2 � 10−2 transconjugants per recipient. Transconjugants were detected in the rumen model for all mating pairs tested; however, the frequencies of transfer were low and inconsistent over 48 h (ranging from 1.0 � 10−9 to 8.0 � 10−6 transconjugants per recipient). The plant model provided an environment that appeared to promote comparatively higher transfer frequencies between all LAB pairs tested over the 9-day period (transfer frequencies ranged from 4.7 � 10−4 to 3.9 � 10−1 transconjugants per recipient). In our test models, dairy cultures of LAB can act as a source of mobile genetic elements encoding antibiotic resistance that can spread to other LAB. This observation could have food safety and public health implications.

scholarly journals Extracellular Vesicles: Intercellular Communication Mediators in Antiphospholipid Syndrome

2021 ◽  
Author(s):  
Ula Štok ◽  
Saša Čučnik ◽  
Snežna Sodin-Šemrl ◽  
Polona Žigon
Keyword(s):  
Extracellular Vesicles ◽  
Antiphospholipid Syndrome ◽  
Intercellular Communication ◽  
Systemic Autoimmune Disease ◽  
In Vivo Models ◽  
Isolation And Characterization ◽  
Increased Risk ◽  
Insight Into

Antiphospholipid syndrome (APS) is a systemic autoimmune disease characterized by thrombosis, obstetric complications and the presence of antiphospholipid antibodies (aPL) that cause endothelial injury and thrombophilia. Extracellular vesicles are involved in endothelial and thrombotic pathologies and may therefore have an influence on the prothrombotic status of APS patients. Intercellular communication and connectivity are important mechanisms of interaction between healthy and pathologically altered cells. Despite well-characterized in vitro and in vivo models of APS pathology, the field of extracellular vesicles is still largely unexplored and could therefore provide an insight into the APS mechanism and possibly serve as a biomarker to identify patients at increased risk. The analysis of EVs poses a challenge due to the lack of standardized technology for their isolation and characterization. Recent findings in the field of EVs offer promising aspects that may explain their role in the pathogenesis of various diseases, including APS.

scholarly journals Emergent Bacteria in Cystic Fibrosis:In VitroBiofilm Formation and Resilience under Variable Oxygen Conditions

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Susana P. Lopes ◽  
Nuno F. Azevedo ◽  
Maria O. Pereira
Keyword(s):  
Bacterial Species ◽  
Low Oxygen ◽  
Antibiotic Susceptibilities ◽  
Oxygen Conditions ◽  
Mode Of Life ◽  
Lung Infections ◽  
Biofilm Development ◽  
The Impact

Concurrent to conventional bacterial pathogens, unusual microbes are emerging from cystic fibrosis (CF) airways. Nonetheless, little is known about the contribution of these newly microbes to the resilience of CF-associated biofilms, particularly under variable-oxygen concentrations that are known to occurin vivoin the mucus of CF patients. Two CF-emergent bacterial species,Inquilinus limosusandDolosigranulum pigrum, and the major pathogenPseudomonas aeruginosawere studied in terms of biofilm development and antibiotic susceptibilities underin vitroatmospheres with different oxygen availabilities. All species were able to developin vitrobiofilms under different oxygen-available environments, withD. pigrumaccumulating high amounts of biomass and respiratory activities. When established, biofilms were of difficult eradication, with antibiotics losing their effectiveness in comparison with the corresponding planktonic populations. Surprisingly, biofilms of each emergent organism displayed multidrug resistance under aerobic environments, enduring even in low-oxygen atmospheres. This study suggests a potential prospect on the impact of nonconventional organismsI. limosusandD. pigrumon CF lung infections, demonstrating capacity to adapt to biofilm mode of life under restricted-oxygen atmospheres resembling CF airways, which may ultimately endanger the efficacy of currently used antibiotic regimens.

Isolation and characterization of macrovascular and microvascular endothelial cells from human hearts

1994 ◽  
Vol 267 (6) ◽  
pp. H2138-H2148 ◽  
Author(s):  
M. Grafe ◽  
W. Auch-Schwelk ◽  
K. Graf ◽  
D. Terbeek ◽  
H. Hertel ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Plasminogen Activator Inhibitor ◽  
Microvascular Endothelial Cells ◽  
Plasminogen Activator Inhibitor 1 ◽  
In Vivo Models ◽  
Isolation And Characterization ◽  
Microvascular Endothelial ◽  
Paramagnetic Beads

In vivo models to investigate mechanisms of local hemostasis in the macro- and microvascular coronary circulation are not available. Therefore, we established a culture system of human macro- and microvascular endothelial cells with high cellular yield and high endothelial cell purity. Microvascular endothelial cells from human hearts were isolated by enzymatic treatment of cardiac muscle preparations obtained during heart transplantation. The isolated microvessels were used to start cultures that were subsequently separated and purified from contaminating nonendothelial cells by paramagnetic beads linked to the lectin Ulex europaeus agglutinin I. Macrovascular endothelial cells were isolated from epicardial coronary arteries and purified by paramagnetic beads as well. With this method high purity (< 2% nonendothelial cells) was achieved as judged from fluorescence-activated cell sorting. Immunochemistry demonstrated the expression of several typical endothelial markers. The two endothelial cell types displayed functional heterogeneity in respect to bradykinin degradation and plasminogen activator inhibitor-1 activity. Thus the ability to selectively isolate and culture human macro- and microvascular cardiac endothelial cells provides a valuable tool to systematically investigate endothelial function in human hearts.

scholarly journals A Family of acr-Coregulated Mycobacterium tuberculosis Genes Shares a Common DNA Motif and Requires Rv3133c (dosR or devR) for Expression

2003 ◽  
Vol 71 (9) ◽  
pp. 5332-5343 ◽  
Author(s):  
Matthew A. Florczyk ◽  
Lee Ann McCue ◽  
Anjan Purkayastha ◽  
Egidio Currenti ◽  
Meyer J. Wolin ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Fluorescent Protein ◽  
Culture Conditions ◽  
Sequence Motif ◽  
Low Oxygen ◽  
Protein Fusion ◽  
Dna Motif ◽  
Oxygen Conditions ◽  
Green Fluorescent

ABSTRACT Previous work has shown that the divergently transcribed Mycobacterium tuberculosis genes acr (hspX, Rv2031c) and acg (Rv2032) are induced under conditions of shallow standing culture and low oxygen and intracellularly within macrophages. We used a combination of computational and experimental methods to identify promoters for eight additional genes that are regulated in a similar manner and that comprise an acr-coregulated promoter (ACP) family. Transcriptional regulation of these ACP family members was evaluated by using a plasmid-based promoter-green fluorescent protein fusion system and flow cytometry. All promoters showed increased expression in shallow standing versus shaking cultures, in low- versus high-oxygen conditions, and intracellularly within macrophages versus extracellularly in tissue culture medium. However, there were quantitative differences in expression among promoters and among conditions for each promoter. A conserved 18-bp palindromic sequence motif was identified in all ACPs by Gibbs sampling-based computational analyses. Two such motifs overlap regions in the acr and acg promoters that were previously shown to be required for their expression. In addition, we found that 5% carbon dioxide was required for growth of Mycobacterium bovis BCG under microaerophilic (1.3% O2) culture conditions and fully prevented the growth cessation typically associated with rapid removal of oxygen. These findings are likely to be relevant to the in vivo environment and will contribute to our understanding of the pathogenesis of tuberculosis infection.

scholarly journals Sperm-specific COX6B2 enhances oxidative phosphorylation, proliferation, and survival in lung adenocarcinoma

2020 ◽  
Author(s):  
Chun-Chun Cheng ◽  
Joshua Wooten ◽  
Zane Gibbs ◽  
Kathleen McGlynn ◽  
Prashant Mishra ◽  
...  
Keyword(s):  
Oxidative Phosphorylation ◽  
Lung Adenocarcinoma ◽  
Cell Metabolism ◽  
Low Oxygen ◽  
Complex Iv ◽  
Cancer Testis Antigens ◽  
Oxygen Conditions ◽  
Necessary And Sufficient ◽  
Proliferative Advantage

ABSTRACTCancer testis antigens (CTAs) are genes whose expression is normally restricted to the testis but anomalously activated in cancer. In sperm, a number of CTAs promote energy generation, however whether these proteins contribute to tumor cell metabolism is not understood. Here we describe COX6B2, a sperm-specific component of cytochrome c oxidase (complex IV). COX6B2 is frequently expressed in human lung adenocarcinoma (LUAD) and expression correlates with reduced survival time in patients. COX6B2, but not its somatic isoform COX6B1, enhances activity of complex IV, increasing mitochondrial oxidative phosphorylation (OXPHOS) and NAD+ generation.Consequently, COX6B2-expressing cells display a proliferative advantage, particularly in low oxygen conditions. Conversely, depletion of COX6B2 attenuates OXPHOS and collapses mitochondrial membrane potential leading to cell death or senescence.Furthermore, COX6B2 is both necessary and sufficient for growth of tumors in vivo. Our findings reveal a previously unappreciated, tumor specific metabolic pathway hijacked from one of the most ATP-intensive processes in the animal kingdom: sperm motility.

scholarly journals Isolation and Characterization of the Novel Phage JD032 and Global Transcriptomic Response during JD032 Infection of Clostridioides difficile Ribotype 078

mSystems ◽  
2020 ◽  
Vol 5 (3) ◽  
Author(s):  
Tinghua Li ◽  
Yan Zhang ◽  
Ke Dong ◽  
Chih-Jung Kuo ◽  
Chong Li ◽  
...  
Keyword(s):  
Gene Expression ◽  
Phage Therapy ◽  
Lytic Infection ◽  
Lytic Cycle ◽  
Bacterial Host ◽  
Content Type ◽  
Isolation And Characterization ◽  
Intestinal Pathogens ◽  
Ribotype 078

ABSTRACT Insights into the interaction between phages and their bacterial hosts are crucial for the development of phage therapy. However, only one study has investigated global gene expression of Clostridioides (formerly Clostridium) difficile carrying prophage, and transcriptional reprogramming during lytic infection has not been studied. Here, we presented the isolation, propagation, and characterization of a newly discovered 35,109-bp phage, JD032, and investigated the global transcriptomes of both JD032 and C. difficile ribotype 078 (RT078) strain TW11 during JD032 infection. Transcriptome sequencing (RNA-seq) revealed the progressive replacement of bacterial host mRNA with phage transcripts. The expressed genes of JD032 were clustered into early, middle, and late temporal categories that were functionally similar. Specifically, a gene (JD032_orf016) involved in the lysis-lysogeny decision was identified as an early expression gene. Only 17.7% (668/3,781) of the host genes were differentially expressed, and more genes were downregulated than upregulated. The expression of genes involved in host macromolecular synthesis (DNA/RNA/proteins) was altered by JD032 at the level of transcription. In particular, the expression of the ropA operon was downregulated. Most noteworthy is that the gene expression of some antiphage systems, including CRISPR-Cas, restriction-modification, and toxin-antitoxin systems, was suppressed by JD032 during infection. In addition, bacterial sporulation, adhesion, and virulence factor genes were significantly downregulated. This study provides the first description of the interaction between anaerobic spore-forming bacteria and phages during lytic infection and highlights new aspects of C. difficile phage-host interactions. IMPORTANCE C. difficile is one of the most clinically significant intestinal pathogens. Although phages have been shown to effectively control C. difficile infection, the host responses to phage predation have not been fully studied. In this study, we reported the isolation and characterization of a new phage, JD032, and analyzed the global transcriptomic changes in the hypervirulent RT078 C. difficile strain, TW11, during phage JD032 infection. We found that bacterial host mRNA was progressively replaced with phage transcripts, three temporal categories of JD032 gene expression, the extensive interplay between phage-bacterium, antiphage-like responses of the host and phage evasion, and decreased expression of sporulation- and virulence-related genes of the host after phage infection. These findings confirmed the complexity of interactions between C. difficile and phages and suggest that phages undergoing a lytic cycle may also cause different phenotypes in hosts, similar to prophages, which may inspire phage therapy for the control of C. difficile.

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