scholarly journals Novel Phage Group Infecting Lactobacillus delbrueckii subsp. lactis, as Revealed by Genomic and Proteomic Analysis of Bacteriophage Ldl1

2014 ◽  
Vol 81 (4) ◽  
pp. 1319-1326 ◽  
Author(s):  
Eoghan Casey ◽  
Jennifer Mahony ◽  
Horst Neve ◽  
Jean-Paul Noben ◽  
Fabio Dal Bello ◽  
...  
Keyword(s):  
Burst Size ◽  
Bacterial Species ◽  
Lactobacillus Delbrueckii ◽  
Comparative Genomic ◽  
Phage Group ◽  
Content Type ◽  
Large Head ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

ABSTRACTLdl1 is a virulent phage infecting the dairy starterLactobacillus delbrueckiisubsp.lactisLdlS. Electron microscopy analysis revealed that this phage exhibits a large head and a long tail and bears little resemblance to other characterized phages infectingLactobacillus delbrueckii.In vitropropagation of this phage revealed a latent period of 30 to 40 min and a burst size of 59.9 ± 1.9 phage particles. Comparative genomic and proteomic analyses showed remarkable similarity between the genome of Ldl1 and that ofLactobacillus plantarumphage ATCC 8014-B2. The genomic and proteomic characteristics of Ldl1 demonstrate that this phage does not belong to any of the four previously recognizedL. delbrueckiiphage groups, necessitating the creation of a new group, called group e, thus adding to the knowledge on the diversity of phages targeting strains of this industrially important lactic acid bacterial species.

scholarly journals Characterization and Comparative Genomic Analysis of a Novel Bacteriophage, SFP10, Simultaneously Inhibiting both Salmonella enterica and Escherichia coli O157:H7

2011 ◽  
Vol 78 (1) ◽  
pp. 58-69 ◽  
Author(s):  
Minjung Park ◽  
Ju-Hoon Lee ◽  
Hakdong Shin ◽  
Minsik Kim ◽  
Jeongjoon Choi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Burst Size ◽  
Genomic Analysis ◽  
Comparative Genomic ◽  
Tail Fiber ◽  
Content Type ◽  
E Coli ◽  
Development Of Resistance

ABSTRACTSalmonella entericaandEscherichia coliO157:H7 are major food-borne pathogens causing serious illness. Phage SFP10, which revealed effective infection of bothS. entericaandE. coliO157:H7, was isolated and characterized. SFP10 contains a 158-kb double-stranded DNA genome belonging to the Vi01 phage-like familyMyoviridae.In vitroadsorption assays showed that the adsorption constant rates to bothSalmonella entericaserovar Typhimurium andE. coliO157:H7 were 2.50 × 10−8ml/min and 1.91 × 10−8ml/min, respectively. One-step growth analysis revealed that SFP10 has a shorter latent period (25 min) and a larger burst size (>200 PFU) than ordinaryMyoviridaephages, suggesting effective host infection and lytic activity. However, differential development of resistance to SFP10 inS.Typhimurium andE. coliO157:H7 was observed; bacteriophage-insensitive mutant (BIM) frequencies of 1.19 × 10−2CFU/ml forS.Typhimurium and 4.58 × 10−5CFU/ml forE. coliO157:H7 were found, indicating that SFP10 should be active and stable for control ofE. coliO157:H7 with minimal emergence of SFP10-resistant pathogens but may not be forS.Typhimurium. Specific mutation ofrfaLinS.Typhimurium andE. coliO157:H7 revealed the O antigen as an SFP10 receptor for both bacteria. Genome sequence analysis of SFP10 and its comparative analysis with homologousSalmonellaVi01 andShigellaphiSboM-AG3 phages revealed that their tail fiber and tail spike genes share low sequence identity, implying that the genes are major host specificity determinants. This is the first report identifying specific infection and inhibition ofSalmonellaTyphimurium andE. coliO157:H7 by a single bacteriophage.

scholarly journals Genomic Investigation of Lysogen Formation and Host Lysis Systems of the Salmonella Temperate Bacteriophage SPN9CC

2013 ◽  
Vol 80 (1) ◽  
pp. 374-384 ◽  
Author(s):  
Hakdong Shin ◽  
Ju-Hoon Lee ◽  
Hyunjin Yoon ◽  
Dong-Hyun Kang ◽  
Sangryeol Ryu
Keyword(s):  
Host Cell ◽  
Burst Size ◽  
Group Analysis ◽  
Genomic Analysis ◽  
Gene Clusters ◽  
Cell Lysis ◽  
Comparative Genomic ◽  
Phage Group ◽  
Content Type ◽  
Lysis Activity

ABSTRACTTo understand phage infection and host cell lysis mechanisms in pathogenicSalmonella, a novelSalmonella entericaserovar Typhimurium-targeting bacteriophage, SPN9CC, belonging to thePodoviridaefamily was isolated and characterized. The phage infectsS. Typhimurium via the O antigen of lipopolysaccharide (LPS) and forms clear plaques with cloudy centers due to lysogen formation. Phylogenetic analysis of phage major capsid proteins revealed that this phage is a member of the lysogen-forming P22-like phage group. However, comparative genomic analysis of SPN9CC with P22-like phages indicated that their lysogeny control regions and host cell lysis gene clusters show very low levels of identity, suggesting that lysogen formation and host cell lysis mechanisms may be diverse among phages in this group. Analysis of the expression of SPN9CC host cell lysis genes encoding holin, endolysin, and Rz/Rz1-like proteins individually or in combinations inS. Typhimurium andEscherichia colihosts revealed that collaboration of these lysis proteins is important for the lysis of both hosts and that holin is a key protein. To further investigate the role of the lysogeny control region in phage SPN9CC, a ΔcImutant (SPN9CCM) of phage SPN9CC was constructed. The mutant does not produce a cloudy center in the plaques, suggesting that this mutant phage is virulent and no longer temperate. Subsequent comparative one-step growth analysis and challenge assays revealed that SPN9CCM has shorter eclipse/latency periods and a larger burst size, as well as higher host cell lysis activity, than SPN9CC. The present work indicates the possibility of engineering temperate phages as promising biocontrol agents similar to virulent phages.

Effects of Various Antioxidant Pretreatment Modalities on Adhesion to Sound and Caries-Affected Dentin: An In Vitro Study

2021 ◽  
pp. 232020682199798
Author(s):  
Beyza Unalan Degirmenci ◽  
Alperen Degirmenci ◽  
Emine Kara
Keyword(s):  
Bond Strength ◽  
In Vitro Study ◽  
Natural Antioxidants ◽  
Microtensile Bond Strength ◽  
Mandibular Molar ◽  
Electron Microscopy Analysis ◽  
Molar Teeth ◽  
Microscopy Analysis ◽  
Two Parameters

Aim: Natural antioxidants were offered as the answer of dentin adhesion issue. The aim of this study is to investigate the effects of proanthocyanidin and lycopene as pretreatment agents on the sound and caries-affected dentin surface on microtensile bond strength and microleakage. Materials and Methods: This study was designed as in vitro because of that 84 mandibular molar teeth were collected. Forty-two of the included teeth were carious teeth, while the other 42 were without caries. Sixty of them were used for microleakage and 24 for microtensile bond strength testing and scanning electron microscopy analysis. The samples were divided into six subgroups randomly according to dentin pretreatments: 5% proanthocyanidin, 5% lycopene, and no antioxidant application. After the restorative procedures, samples were attached to the microtensile tester. Samples were subjected to tensile stress in the load cell until they broke at a speed of 0.5 mm per min. Microtensile bond strength (µTBS) and microleakage test data were analyzed with two-way analysis of variance, Bonferroni correction, and Tamhane’s T2 tests. Results: Two-way variance analysis showed that dentin pretreatment applications, dentin substrate, and the interaction between these two parameters had statistically significant effects on µTBS values ( P < .001). There was no difference between dentin pretreatment applications in terms of microleakage scores ( P > .05). Conclusion: The application of dentin pretreatment with proanthocyanidin is a successful procedure that increases the bond strength in both dentin substrate, while pretreatment with lycopene in caries-affected dentin reduces it.

scholarly journals Antiparasitic Properties of Cardiovascular Agents against Human Intravascular Parasite Schistosoma mansoni

2021 ◽  
Vol 14 (7) ◽  
pp. 686
Author(s):  
Raquel Porto ◽  
Ana C. Mengarda ◽  
Rayssa A. Cajas ◽  
Maria C. Salvadori ◽  
Fernanda S. Teixeira ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Screening Strategy ◽  
Early Infection ◽  
Global Public Health ◽  
Parasitic Worm ◽  
Electron Microscopy Analysis ◽  
Health Significance ◽  
Microscopy Analysis

The intravascular parasitic worm Schistosoma mansoni is a causative agent of schistosomiasis, a disease of great global public health significance. Praziquantel is the only drug available to treat schistosomiasis and there is an urgent demand for new anthelmintic agents. Adopting a phenotypic drug screening strategy, here, we evaluated the antiparasitic properties of 46 commercially available cardiovascular drugs against S. mansoni. From these screenings, we found that amiodarone, telmisartan, propafenone, methyldopa, and doxazosin affected the viability of schistosomes in vitro, with effective concentrations of 50% (EC50) and 90% (EC90) values ranging from 8 to 50 µM. These results were further supported by scanning electron microscopy analysis. Subsequently, the most effective drug (amiodarone) was further tested in a murine model of schistosomiasis for both early and chronic S. mansoni infections using a single oral dose of 400 mg/kg or 100 mg/kg daily for five consecutive days. Amiodarone had a low efficacy in chronic infection, with the worm and egg burden reduction ranging from 10 to 30%. In contrast, amiodarone caused a significant reduction in worm and egg burden in early infection (>50%). Comparatively, treatment with amiodarone is more effective in early infection than praziquantel, demonstrating the potential role of this cardiovascular drug as an antischistosomal agent.

scholarly journals Enhancing Terpene Yield from Sugars via Novel Routes to 1-Deoxy-d-Xylulose 5-Phosphate

2014 ◽  
Vol 81 (1) ◽  
pp. 130-138 ◽  
Author(s):  
James Kirby ◽  
Minobu Nishimoto ◽  
Ruthie W. N. Chow ◽  
Edward E. K. Baidoo ◽  
George Wang ◽  
...  
Keyword(s):  
Bacterial Species ◽  
Xylose Reductase ◽  
Pentose Phosphate ◽  
Terpene Biosynthesis ◽  
Content Type ◽  
E Coli ◽  
Pathway Expression ◽  
Terpene Synthesis ◽  
Selection For

ABSTRACTTerpene synthesis in the majority of bacterial species, together with plant plastids, takes place via the 1-deoxy-d-xylulose 5-phosphate (DXP) pathway. The first step of this pathway involves the condensation of pyruvate and glyceraldehyde 3-phosphate by DXP synthase (Dxs), with one-sixth of the carbon lost as CO2. A hypothetical novel route from a pentose phosphate to DXP (nDXP) could enable a more direct pathway from C5sugars to terpenes and also circumvent regulatory mechanisms that control Dxs, but there is no enzyme known that can convert a sugar into its 1-deoxy equivalent. Employing a selection for complementation of adxsdeletion inEscherichia coligrown on xylose as the sole carbon source, we uncovered two candidate nDXP genes. Complementation was achieved either via overexpression of the wild-typeE. coliyajOgene, annotated as a putative xylose reductase, or via various mutations in the nativeribBgene.In vitroanalysis performed with purified YajO and mutant RibB proteins revealed that DXP was synthesized in both cases from ribulose 5-phosphate (Ru5P). We demonstrate the utility of these genes for microbial terpene biosynthesis by engineering the DXP pathway inE. colifor production of the sesquiterpene bisabolene, a candidate biodiesel. To further improve flux into the pathway from Ru5P, nDXP enzymes were expressed as fusions to DXP reductase (Dxr), the second enzyme in the DXP pathway. Expression of a Dxr-RibB(G108S) fusion improved bisabolene titers more than 4-fold and alleviated accumulation of intracellular DXP.

scholarly journals An Evolutionary Link between Natural Transformation and CRISPR Adaptive Immunity

mBio ◽  
2012 ◽  
Vol 3 (5) ◽  
Author(s):  
Peter Jorth ◽  
Marvin Whiteley
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Bacterial Diversity ◽  
Natural Transformation ◽  
Bacterial Species ◽  
Comparative Genomic ◽  
Content Type ◽  
Immune Systems ◽  
Adaptive Immune ◽  
Adaptive Immune Systems

ABSTRACTNatural transformation by competent bacteria is a primary means of horizontal gene transfer; however, evidence that competence drives bacterial diversity and evolution has remained elusive. To test this theory, we used a retrospective comparative genomic approach to analyze the evolutionary history ofAggregatibacter actinomycetemcomitans, a bacterial species with both competent and noncompetent sister strains. Through comparative genomic analyses, we reveal that competence is evolutionarily linked to genomic diversity and speciation. Competence loss occurs frequently during evolution and is followed by the loss of clustered regularly interspaced short palindromic repeats (CRISPRs), bacterial adaptive immune systems that protect against parasitic DNA. Relative to noncompetent strains, competent bacteria have larger genomes containing multiple rearrangements. In contrast, noncompetent bacterial genomes are extremely stable but paradoxically susceptible to infective DNA elements, which contribute to noncompetent strain genetic diversity. Moreover, incomplete noncompetent strain CRISPR immune systems are enriched for self-targeting elements, which suggests that the CRISPRs have been co-opted for bacterial gene regulation, similar to eukaryotic microRNAs derived from the antiviral RNA interference pathway.IMPORTANCEThe human microbiome is rich with thousands of diverse bacterial species. One mechanism driving this diversity is horizontal gene transfer by natural transformation, whereby naturally competent bacteria take up environmental DNA and incorporate new genes into their genomes. Competence is theorized to accelerate evolution; however, attempts to test this theory have proved difficult. Through genetic analyses of the human periodontal pathogenAggregatibacter actinomycetemcomitans, we have discovered an evolutionary connection between competence systems promoting gene acquisition and CRISPRs (clustered regularly interspaced short palindromic repeats), adaptive immune systems that protect bacteria against genetic parasites. We show that competentA. actinomycetemcomitansstrains have numerous redundant CRISPR immune systems, while noncompetent bacteria have lost their CRISPR immune systems because of inactivating mutations. Together, the evolutionary data linking the evolution of competence and CRISPRs reveals unique mechanisms promoting genetic heterogeneity and the rise of new bacterial species, providing insight into complex mechanisms underlying bacterial diversity in the human body.

scholarly journals RNA G-Quadruplex Structures Mediate Gene Regulation in Bacteria

mBio ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiaolong Shao ◽  
Weitong Zhang ◽  
Mubarak Ishaq Umar ◽  
Hei Yuen Wong ◽  
Zijing Seng ◽  
...  
Keyword(s):  
Gene Regulation ◽  
Cell Envelope ◽  
Bacterial Species ◽  
Virulence Gene ◽  
Content Type ◽  
Cellular Processes ◽  
Wide Range ◽  
G Quadruplex ◽  
Eukaryotic Organisms

ABSTRACT Guanine (G)-rich sequences in RNA can fold into diverse RNA G-quadruplex (rG4) structures to mediate various biological functions and cellular processes in eukaryotic organisms. However, the presence, locations, and functions of rG4s in prokaryotes are still elusive. We used QUMA-1, an rG4-specific fluorescent probe, to detect rG4 structures in a wide range of bacterial species both in vitro and in live cells and found rG4 to be an abundant RNA secondary structure across those species. Subsequently, to identify bacterial rG4 sites in the transcriptome, the model Escherichia coli strain and a major human pathogen, Pseudomonas aeruginosa, were subjected to recently developed high-throughput rG4 structure sequencing (rG4-seq). In total, 168 and 161 in vitro rG4 sites were found in E. coli and P. aeruginosa, respectively. Genes carrying these rG4 sites were found to be involved in virulence, gene regulation, cell envelope synthesis, and metabolism. More importantly, biophysical assays revealed the formation of a group of rG4 sites in mRNAs (such as hemL and bswR), and they were functionally validated in cells by genetic (point mutation and lux reporter assays) and phenotypic experiments, providing substantial evidence for the formation and function of rG4s in bacteria. Overall, our study uncovers important regulatory functions of rG4s in bacterial pathogenicity and metabolic pathways and strongly suggests that rG4s exist and can be detected in a wide range of bacterial species. IMPORTANCE G-quadruplex in RNA (rG4) mediates various biological functions and cellular processes in eukaryotic organisms. However, the presence, locations, and functions of rG4 are still elusive in prokaryotes. Here, we found that rG4 is an abundant RNA secondary structure across a wide range of bacterial species. Subsequently, the transcriptome-wide rG4 structure sequencing (rG4-seq) revealed that the model E. coli strain and a major human pathogen, P. aeruginosa, have 168 and 161 in vitro rG4 sites, respectively, involved in virulence, gene regulation, cell envelope, and metabolism. We further verified the regulatory functions of two rG4 sites in bacteria (hemL and bswR). Overall, this finding strongly suggests that rG4s play key regulatory roles in a wide range of bacterial species.

scholarly journals Nitroxide Functionalized Antibiotics Are Promising Eradication Agents against Staphylococcus aureus Biofilms

2019 ◽  
Vol 64 (1) ◽  
Author(s):  
Anthony D. Verderosa ◽  
Rabeb Dhouib ◽  
Kathryn E. Fairfull-Smith ◽  
Makrina Totsika
Keyword(s):  
Staphylococcus Aureus ◽  
Bacterial Biofilms ◽  
Gram Positive ◽  
Gram Negative ◽  
Content Type ◽  
Microscopy Analysis ◽  
Biofilm Dispersal ◽  
Biofilm Structure ◽  
Dispersal Activity

ABSTRACT Treatment of biofilm-related Staphylococcus aureus infections represents an important medical challenge worldwide, as biofilms, even those involving drug-susceptible S. aureus strains, are highly refractory to conventional antibiotic therapy. Nitroxides were recently shown to induce the dispersal of Gram-negative biofilms in vitro, but their action against Gram-positive bacterial biofilms remains unknown. Here, we demonstrate that the biofilm dispersal activity of nitroxides extends to S. aureus, a clinically important Gram-positive pathogen. Coadministration of the nitroxide CTEMPO (4-carboxy-2,2,6,6-tetramethylpiperidin-1-yloxyl) with ciprofloxacin significantly improved the biofilm eradication activity of the antibiotic against S. aureus. Moreover, covalently linking the nitroxide to the antibiotic moiety further reduced the ciprofloxacin minimal biofilm eradication concentration. Microscopy analysis revealed that fluorescent nitroxide-antibiotic hybrids could penetrate S. aureus biofilms and enter cells localized at the surface and base of the biofilm structure. No toxicity to human cells was observed for the nitroxide CTEMPO or the nitroxide-antibiotic hybrids. Taken together, our results show that nitroxides can mediate the dispersal of Gram-positive biofilms and that dual-acting biofilm eradication antibiotics may provide broad-spectrum therapies for the treatment of biofilm-related infections.

A new insight into corrosion inhibition process of mild steel in sulfuric acid medium: a combined experimental and theoretical study

2019 ◽  
Vol 66 (6) ◽  
pp. 835-852 ◽  
Author(s):  
Aziz Boutouil ◽  
My Rachid Laamari ◽  
Ilham Elazhary ◽  
Hafid Anane ◽  
Abdeslem Ben Tama ◽  
...  
Keyword(s):  
Mild Steel ◽  
Inhibition Efficiency ◽  
Electrochemical Impedance ◽  
Acid Corrosion ◽  
Content Type ◽  
Sulfuric Acid Medium ◽  
Ir Studies ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
Structural Parts

Purpose This study aims to investigate the inhibition effect of a newly synthesized1,2,3-triazole containing a carbohydrate and imidazole substituents, namely, 1-((1-((2,2,7,7-tetramethyltetrahydro-5H-bis([1,3]dioxolo)[4,5-b:4′,5′-d]pyran-5-yl)methyl)-1H-1,2,3-triazol-4-yl)methyl)-1H-benzo[d]imidazole (TTB) on the corrosion of mild steel in aerated 1 M H2SO4. Design/methodology/approach The authors have used weight loss measurement, potentiodynamic polarization, electrochemical impedance spectroscopy, FT-IR studies, scanning electron microscopy analysis and energy dispersive X-ray (EDX) spectroscopy techniques. Findings It is found that, in the working range of 298-328 K, the inhibition efficiency of TTB increases with increasing concentration to attain the highest value (92 per cent) at 2.5 × 10−3 M. Both chemisorption and physisorption of TTB take place on the mild steel, resulting in the formation of an inhibiting film. Computational methods point to the imidazole and phenyl ring as the main structural parts responsible of adsorption by electron-donating to the steel surface, while the triazol ring is responsible for the electron accepting. Such strong donating–accepting interactions lead to higher inhibition efficiency of TTB in the aqueous working system. Originality/value This work is original with the aim of finding new acid corrosion inhibitors.

scholarly journals Interspecies Inhibition ofPorphyromonas gingivalisby Yogurt-DerivedLactobacillus delbrueckiiRequires Active Pyruvate Oxidase

2019 ◽  
Vol 85 (18) ◽  
Author(s):  
Louis P. Cornacchione ◽  
Brian A. Klein ◽  
Margaret J. Duncan ◽  
Linden T. Hu
Keyword(s):  
Hydrogen Peroxide ◽  
Periodontal Disease ◽  
Microbial Interactions ◽  
Lactobacillus Delbrueckii ◽  
Species Selection ◽  
Probiotic Bacteria ◽  
Pyruvate Oxidase ◽  
Hydrogen Peroxide Production ◽  
Content Type

ABSTRACTDespite a growing interest in using probiotic microorganisms to prevent disease, the mechanisms by which probiotics exert their action require further investigation.Porphyromonas gingivalisis an important pathogen implicated in the development of periodontitis. We isolated several strains ofLactobacillus delbrueckiifrom dairy products and examined their ability to inhibitP. gingivalisgrowthin vitro. We observed strain-specific inhibition ofP. gingivalisgrowthin vitro. Whole-genome sequencing of inhibitory and noninhibitory strains ofL. delbrueckiirevealed significant genetic differences supporting the strain specificity of the interaction. Extracts of theL. delbrueckiiSTYM1 inhibitory strain contain inhibitory activity that is abolished by treatment with heat, proteinase K, catalase, and sodium sulfite. We purified the inhibitory protein(s) fromL. delbrueckiiSTYM1 extracts using ammonium sulfate precipitation, anion-exchange chromatography, and gel filtration chromatography. Pyruvate oxidase was highly enriched in the purified samples. Lastly, we showed that purified, catalytically active, recombinant pyruvate oxidase is sufficient to inhibitP. gingivalisgrowthin vitrowithout the addition of cofactors. Further, using a saturated transposon library, we isolated transposon mutants ofP. gingivalisin thefeoB2(PG_1294) gene that are resistant to killing by inhibitoryL. delbrueckii, consistent with a mechanism of hydrogen peroxide production by pyruvate oxidase. Our results support the current understanding of the importance of strain selection, not simply species selection, in microbial interactions. SpecificL. delbrueckiistrains or their products may be effective in the treatment and prevention ofP. gingivalis-associated periodontal disease.IMPORTANCEP. gingivalisis implicated in the onset and progression of periodontal disease and associated with some systemic diseases. Probiotic bacteria represent an attractive preventative therapy for periodontal disease. However, the efficacy of probiotic bacteria can be variable between studies. Our data support the known importance of selecting particular strains of bacteria for probiotic use, not simply a single species. Specifically, in the context of probiotic intervention of periodontitis, our data suggest that high-level expression of pyruvate oxidase with hydrogen peroxide production inL. delbrueckiicould be an important characteristic for the design of a probiotic supplement or a microbial therapeutic.

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