6 results on '"Agnès Roba"'
Search Results
2. Histidine auxotroph mutant is defective for cell separation and allows the identification of crucial factors for cell division in Brucella abortus
- Author
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Agnès Roba, Elodie Carlier, Pierre Godessart, Cerine Naili, and Xavier De Bolle
- Subjects
Bacterial Proteins ,Brucella abortus ,Humans ,Histidine ,Cell Separation ,Peptidoglycan ,Brucella ,Molecular Biology ,Microbiology ,Brucellosis ,Cell Division - Abstract
The pathogenic bacterium Brucella abortus invades and multiplies inside host cells. To grow inside host cells, B. abortus requires a functional histidine biosynthesis pathway. Here, we show that a B. abortus histidine auxotroph mutant also displays an unexpected chaining phenotype. The intensity of this phenotype varies according to the culture medium and is exacerbated inside host cells. Chains of bacteria consist of contiguous peptidoglycan, and likely result from the defective cleavage of peptidoglycan at septa. Genetic suppression of the chaining phenotype unearthed two essential genes with a role in B. abortus cell division: dipM and cdlP. Loss of function of dipM and cdlP generates swelling at the division site. While DipM is strictly localized at the division site, CdlP is localized at the growth pole and the division site. Altogether, the unexpected chaining phenotype of a hisB mutant allowed the discovery of new crucial actors in cell division in B. abortus.
- Published
- 2022
3. Prevention of horizontal transfer of laboratory plasmids to environmental bacteria: comparison of the effectiveness of a few disinfection approaches to degrade DNA
- Author
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Suzanne Marie LORET, Boutaina HABIB, Pierre ROMAIN, Agnès ROBA, and Angéline REBOUL
- Abstract
The routine work of any molecular biology laboratory includes the daily use of microorganisms, including strains of E. coli, transformed with a variety of plasmids expressing at least one antibiotic resistance gene (ARG). To verify the effectiveness of disinfection methods on laboratory liquid waste, bacteria isolated from laboratory and research institute drains were identified by 16S ribosomal RNA sequencing and tested for the presence of an origin of replication and several ARGs frequently found in laboratory plasmids. Surprisingly, the origin of replication of Enterobacteriaceae plasmids was detected in strains of non-Enterobacteriaceae bacteria suggesting that interspecific transfer of laboratory plasmids had occurred. Using quantitative Polymerase Chain Reaction, we determined the Decimal reduction value (D-value, expressed as concentration of disinfectant or length of physical treatment) of several decontamination methods for their DNA degradation effect on cultures of E. coli Top10 transformed with a kanamycin resistant plasmid (pET28A + or pEGFP-C2). The estimated D-values were 0,7 M for Sulfuric, 6,3% for a commercial P3 disinfectant, 25 minutes for steam sterilization at 121°C and 49 minutes for disinfection by UVC. A 20-minute treatment of bacteria cultures with a final concentration of 1–10% sodium hypochlorite was found to be ineffective in completely destroying a bacteria plasmid gene marker (coding for the pBR322 origin of replication). Residual DNA from HClO treated cells was 60%, while it decreased under 10% using the commercial disinfectant P3 diluted at 5%. As the degradation was uncomplete in both cases, to prevent the horizontal transfer of laboratory ARGs to environmental bacteria, disinfected liquid waste should not be released in sewage without additional plasmid destruction treatment.
- Published
- 2023
4. Prevention of horizontal transfer of laboratory plasmids to environmental bacteria: how to select disinfection methods that are also effective in destroying DNA
- Author
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Suzanne Marie LORET, Boutaina HABIB, Pierre Romain, Agnès Roba, and Angéline Reboul
- Abstract
Routine work of any molecular biology laboratory includes the daily use of microorganisms, including non-pathogenic E coli strains, transformed with a variety of plasmids expressing at least one antibiotic resistance gene (ARG). To check the efficacy of neutralization methods, bacteria isolated from wastewater from laboratories and research institutes were identified using the 16S ribosomal RNA sequencing and they were tested for the presence of an origin of replication and several ARGs frequently found in laboratory plasmids. Surprisingly, the origin of replication of Enterobacteriaceae was detected in non-Enterobacteriaceae bacteria strains suggesting that an interspecies transfer of laboratory plasmids had occurred. Using quantitative Polymerase Chain Reaction (qPCR), we determined the Decimal reduction value (D-value, expressed as concentration of disinfectant or length of physical treatment) of several neutralization methods for their DNA-bd effect: i.e. 0.7M for Sulfuric, 3.2% for a commercial disinfectant P3, 25 minutes for steam sterilization at 121°C and 49 minutes for UVC. A 20-minute treatment of laboratory liquid waste (LLW) with 1–10% sodium chlorine is ineffective in destroying completely plasmid gene markers intreated cells. Therefore, to prevent the horizontal transfer of laboratory ARGs to environmental bacteria, bleach-treated liquid waste should not be released in sewage without additional plasmid destruction treatment.
- Published
- 2022
5. Occurrence and repair of alkylating stress in the intracellular pathogen Brucella abortus
- Author
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Xavier De Bolle, Arnaud Machelart, Katy Poncin, Eric Muraille, Emanuele G. Biondi, Nayla Francis, Agnès Roba, Kevin Willemart, Nicolas Zeippen, Georges Potemberg, Antonella Fioravanti, Stéphane P. Vincent, Ravikumar Jimmidi, Department of Bio-engineering Sciences, Research Unit in Molecular Biology (URBM-NARILIS), Université de Namur [Namur] (UNamur), Unité de Chimie Organique University of Namur, Unité de Glycobiologie Structurale et Fonctionnelle UMR 8576 (UGSF), Université de Lille-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de chimie bactérienne (LCB), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Institut de Microbiologie de la Méditerranée (IMM), University of Oxford [Oxford], Fédération Wallonie-Bruxelles (ARC 17/22-087) and by the FRS-FNRS 'Brucell-cycle' (PDR T.0060.15), ANR-11-JSV3-0003,CASTACC,Analyse comparative des facteurs de transduction des signaux contrôlant la régulation du cycle cellulaire chez les alpha-protéobactéries(2011), Université de Namur [Namur], Unité de Glycobiologie Structurale et Fonctionnelle - UMR 8576 (UGSF), Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), ANR: Analyse comparative des facteurs de transduction des signaux contrôlant la régulation du cycle cellulaire chez les alpha-protéobactéries – CASTACC,Projet CASTACC,ANR-JCJC-2011-Castacc, Université de Lille-Centre National de la Recherche Scientifique (CNRS), and University of Oxford
- Subjects
0301 basic medicine ,Alkylation ,DNA Repair ,[SDV]Life Sciences [q-bio] ,Cellular microbiology ,Brucella abortus ,General Physics and Astronomy ,medicine.disease_cause ,DNA damage response ,Mice ,chemistry.chemical_compound ,lcsh:Science ,Pathogen ,Multidisciplinary ,3. Good health ,Technologie de l'environnement, contrôle de la pollution ,Host-Pathogen Interactions ,Pathogens ,DNA repair ,Science ,030106 microbiology ,Biology ,Article ,Brucellosis ,General Biochemistry, Genetics and Molecular Biology ,Microbiology ,03 medical and health sciences ,Stress, Physiological ,medicine ,Animals ,Chimie ,Gene ,Escherichia coli ,Transcription factor ,Physique ,Macrophages ,DNA adducts ,Pathogenic bacteria ,General Chemistry ,DNA Methylation ,Astronomie ,RAW 264.7 Cells ,030104 developmental biology ,chemistry ,Vacuoles ,lcsh:Q ,DNA ,DNA Damage - Abstract
It is assumed that intracellular pathogenic bacteria have to cope with DNA alkylating stress within host cells. Here we use single-cell reporter systems to show that the pathogen Brucella abortus does encounter alkylating stress during the first hours of macrophage infection. Genes encoding direct repair and base-excision repair pathways are required by B. abortus to face this stress in vitro and in a mouse infection model. Among these genes, ogt is found to be under the control of the conserved cell-cycle transcription factor GcrA. Our results highlight that the control of DNA repair in B. abortus displays distinct features that are not present in model organisms such as Escherichia coli., SCOPUS: ar.j, info:eu-repo/semantics/published
- Published
- 2019
6. Service contracting as a policy response for public transport recovery during the Covid-19 Pandemic: A preliminary evaluation
- Author
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Varsolo Sunio, Wilhansen Joseph Li, Joemier Pontawe, Albert Dizon, Joel Bienne Valderrama, and Agnes Robang
- Subjects
Service contracting ,Covid-19 pandemic ,Policy evaluation ,Global South ,Transportation and communications ,HE1-9990 - Abstract
We examine and assess the service contracting (SC) program implemented for the first time in Metro Manila, Philippines as a response to the impact of the pandemic on road-based public transport sector. We develop an evaluation framework, consisting of three indicators: social amelioration, increase in transport supply and performance improvement. These indicators are the purported objectives of SC. Using a mix of qualitative and quantitative methods, our evaluation suggests that although SC has brought positive impact in terms of the first two indicators, there is no robust evidence so far that may suggest that SC has improved the performance of public transport service delivery. We also find that while the primary objective of providing social amelioration to affected operators is appropriate during the time of the pandemic, this has also brought challenges in financially sustaining the program and in effecting improvements to public transport services. Our work aims to contribute as an empirical case study on the upsides and downsides of service contracting implemented as a business model for public transport provision during the pandemic.
- Published
- 2022
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