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Servain-Viel S, Aknin ML, Domenichini S, Perlemuter G, Cassard AM, Schlecht-Louf G, Moal VLL. A flow cytometry method for safe detection of bacterial viability. Cytometry A 2024; 105:146-156. [PMID: 37786349 DOI: 10.1002/cyto.a.24794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 08/18/2023] [Accepted: 09/04/2023] [Indexed: 10/04/2023]
Abstract
Flow cytometry is a relevant tool to meet the requirements of academic and industrial research projects aimed at estimating the features of a bacterial population (e.g., quantity, viability, activity). One of the remaining challenges is now the safe assessment of bacterial viability while minimizing the risks inherent to existing protocols. In our core facility at the Paris-Saclay University, we have addressed this issue with two objectives: measuring bacterial viability in biological samples and preventing bacterial contamination and chemical exposure of the staff and cytometers used on the platform. Here, we report the development of a protocol achieving these two objectives, including a viability labeling step before bacteria fixation, which removes the risk of biological exposure, and the decrease of the use of reagents such as propidium iodide (PI), which are dangerous for health (CMR: carcinogenic, mutagenic, and reprotoxic). For this purpose, we looked for a non-CMR viability dye that can irreversibly label dead bacteria before fixation procedures and maintain intense fluorescence after further staining. We decided to test on the bacteria, eFluor Fixable Viability dyes, which are usually used on eukaryotic cells. Since the bacteria had size and granularity characteristics very similar to those associated with flow cytometry background signals, a step of bacterial DNA labeling with SYTO or DRAQ5 was necessarily added to differentiate them from the background. Three marker combinations (viability-DNA) were tested on LSR Fortessa and validated on pure bacterial populations (Gram+ , Gram- ) and polybacterial cultures. Any of the three methods can be used and adapted to the needs of each project and allow users to adapt the combination according to the configuration of their cytometer. Having been tested on six bacterial populations, validated on two cytometers, and repeated at least two times in each evaluated condition, we consider this method reliable in the context of these conditions. The reliability of the results obtained in flow cytometry was successfully validated by applying this protocol to confocal microscopy, permeabilization, and also to follow cultures over time. This flow cytometry protocol for measuring bacterial viability under safer conditions also opens the prospect of its use for further bacterial characterization.
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Affiliation(s)
- S Servain-Viel
- Plateforme CYM - UMS-IPSIT, Université Paris-Saclay, Inserm, CNRS, Ingénierie et Plateformes au Service de l'Innovation Thérapeutique, Orsay, France
| | - M-L Aknin
- Plateforme CYM - UMS-IPSIT, Université Paris-Saclay, Inserm, CNRS, Ingénierie et Plateformes au Service de l'Innovation Thérapeutique, Orsay, France
| | - S Domenichini
- Plateforme MIPSIT - UMS-IPSIT, Université Paris-Saclay, Inserm, CNRS, Ingénierie et Plateformes au Service de l'Innovation Thérapeutique, Orsay, France
| | - G Perlemuter
- Inflammation, Microbiome and Immunosurveillance, UMR-996, Université Paris-Saclay, Inserm, Orsay, France
- Service d'Hépato-Gastroentérologie Et Nutrition, Hôpital Antoine-Béclère, AP- HP Université Paris-Saclay, Clamart, France
| | - A-M Cassard
- Inflammation, Microbiome and Immunosurveillance, UMR-996, Université Paris-Saclay, Inserm, Orsay, France
| | - G Schlecht-Louf
- Inflammation, Microbiome and Immunosurveillance, UMR-996, Université Paris-Saclay, Inserm, Orsay, France
| | - V Lievin-Le Moal
- Inflammation, Microbiome and Immunosurveillance, UMR-996, Université Paris-Saclay, Inserm, Orsay, France
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Bidan N, Lores S, Vanhecke A, Nicolas V, Domenichini S, López R, de la Fuente M, Mura S. Before in vivo studies: In vitro screening of sphingomyelin nanosystems using a relevant 3D multicellular pancreatic tumor spheroid model. Int J Pharm 2022; 617:121577. [PMID: 35167901 DOI: 10.1016/j.ijpharm.2022.121577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 02/07/2022] [Accepted: 02/09/2022] [Indexed: 12/13/2022]
Abstract
Sphingomyelin nanosystems have already shown to be promising carriers for efficient delivery of anticancer drugs. For further application in the treatment of pancreatic tumor, the investigation on relevant in vitro models able to reproduce its physio-pathological complexity, is mandatory. Accordingly, a 3D heterotype spheroid model of pancreatic tumor has been herein constructed to investigate the potential of bare and polyethylene glycol-modified lipids nanosystems in terms of their ability to penetrate the tumor mass and deliver drugs. Regardless of their surface properties, the lipid nanosystems successfully diffused through the spheroid without inducing toxicity, showing a clear safety profile. Loading of the bare nanosystems with a lipid prodrug of gemcitabine was used to evaluate their therapeutic potential. While the nanosystems were more effective than the free drug on 2D cell monocultures, this advantage, despite their efficient penetration capacity, was lost in the 3D tumor model. The latter, being able to mimic the tumor and its microenvironment, was capable to provide a more realistic information on the cell sensitivity to treatments. These results highlight the importance of using appropriate 3D tumour models as tools for proper in vitro evaluation of nanomedicine efficacy and their timely optimisation, so as to identify the best candidates for later in vivo evaluation.
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Affiliation(s)
- Nadege Bidan
- Institut Galien Paris-Saclay, UMR 8612, CNRS, Université Paris-Saclay, Faculté de Pharmacie, 5 rue Jean-Baptiste Clément, F92296 Châtenay-Malabry cedex, France
| | - Saínza Lores
- Nano-Oncology and Translational Therapeutics Unit, Health Research Institute of Santiago de Compostela (IDIS), SERGAS, 15706 Santiago de Compostela, Spain
| | - Aure Vanhecke
- Institut Galien Paris-Saclay, UMR 8612, CNRS, Université Paris-Saclay, Faculté de Pharmacie, 5 rue Jean-Baptiste Clément, F92296 Châtenay-Malabry cedex, France
| | - Valérie Nicolas
- UMS-IPSIT MIPSIT Microscopy facility, Université Paris-Saclay, Inserm, CNRS, Ingénierie et Plateformes au Service de l'Innovation Thérapeutique, 92296, Châtenay-Malabry, France
| | - Severine Domenichini
- UMS-IPSIT MIPSIT Microscopy facility, Université Paris-Saclay, Inserm, CNRS, Ingénierie et Plateformes au Service de l'Innovation Thérapeutique, 92296, Châtenay-Malabry, France
| | - Rafael López
- Translational Medical Oncology group (ONCOMET), Health Research Institute of Santiago de Compostela (IDIS), SERGAS, 15706 Santiago de Compostela, Spain; Biomedical Research Networking Center on Oncology (CIBERONC), Madrid, 28029, Spain
| | - María de la Fuente
- Nano-Oncology and Translational Therapeutics Unit, Health Research Institute of Santiago de Compostela (IDIS), SERGAS, 15706 Santiago de Compostela, Spain; Biomedical Research Networking Center on Oncology (CIBERONC), Madrid, 28029, Spain.
| | - Simona Mura
- Institut Galien Paris-Saclay, UMR 8612, CNRS, Université Paris-Saclay, Faculté de Pharmacie, 5 rue Jean-Baptiste Clément, F92296 Châtenay-Malabry cedex, France.
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Concia L, Veluchamy A, Ramirez-Prado JS, Martin-Ramirez A, Huang Y, Perez M, Domenichini S, Rodriguez Granados NY, Kim S, Blein T, Duncan S, Pichot C, Manza-Mianza D, Juery C, Paux E, Moore G, Hirt H, Bergounioux C, Crespi M, Mahfouz MM, Bendahmane A, Liu C, Hall A, Raynaud C, Latrasse D, Benhamed M. Wheat chromatin architecture is organized in genome territories and transcription factories. Genome Biol 2020; 21:104. [PMID: 32349780 PMCID: PMC7189446 DOI: 10.1186/s13059-020-01998-1] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 03/12/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Polyploidy is ubiquitous in eukaryotic plant and fungal lineages, and it leads to the co-existence of several copies of similar or related genomes in one nucleus. In plants, polyploidy is considered a major factor in successful domestication. However, polyploidy challenges chromosome folding architecture in the nucleus to establish functional structures. RESULTS We examine the hexaploid wheat nuclear architecture by integrating RNA-seq, ChIP-seq, ATAC-seq, Hi-C, and Hi-ChIP data. Our results highlight the presence of three levels of large-scale spatial organization: the arrangement into genome territories, the diametrical separation between facultative and constitutive heterochromatin, and the organization of RNA polymerase II around transcription factories. We demonstrate the micro-compartmentalization of transcriptionally active genes determined by physical interactions between genes with specific euchromatic histone modifications. Both intra- and interchromosomal RNA polymerase-associated contacts involve multiple genes displaying similar expression levels. CONCLUSIONS Our results provide new insights into the physical chromosome organization of a polyploid genome, as well as on the relationship between epigenetic marks and chromosome conformation to determine a 3D spatial organization of gene expression, a key factor governing gene transcription in polyploids.
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Affiliation(s)
- Lorenzo Concia
- Institute of Plant Sciences Paris of Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Orsay, France
| | - Alaguraj Veluchamy
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Juan S Ramirez-Prado
- Institute of Plant Sciences Paris of Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Orsay, France
| | | | - Ying Huang
- Institute of Plant Sciences Paris of Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Orsay, France
| | - Magali Perez
- Institute of Plant Sciences Paris of Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Orsay, France
| | - Severine Domenichini
- Institute of Plant Sciences Paris of Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Orsay, France
| | | | - Soonkap Kim
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Thomas Blein
- Institute of Plant Sciences Paris of Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Orsay, France
| | - Susan Duncan
- Earlham Institute, Norwich Research Park, Norwich, NR4 7UG, UK
| | - Clement Pichot
- Institute of Plant Sciences Paris of Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Orsay, France
| | - Deborah Manza-Mianza
- Institute of Plant Sciences Paris of Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Orsay, France
| | - Caroline Juery
- INRA UMR1095 Genetics, Diversity and Ecophysiology of Cereals, 5 chemin de Beaulieu, 63039, Clermont-Ferrand, France
| | - Etienne Paux
- INRA UMR1095 Genetics, Diversity and Ecophysiology of Cereals, 5 chemin de Beaulieu, 63039, Clermont-Ferrand, France
| | - Graham Moore
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Heribert Hirt
- Institute of Plant Sciences Paris of Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Orsay, France
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Catherine Bergounioux
- Institute of Plant Sciences Paris of Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Orsay, France
| | - Martin Crespi
- Institute of Plant Sciences Paris of Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Orsay, France
| | - Magdy M Mahfouz
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Abdelhafid Bendahmane
- Institute of Plant Sciences Paris of Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Orsay, France
| | - Chang Liu
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, 72076, Tübingen, Germany
| | - Anthony Hall
- Earlham Institute, Norwich Research Park, Norwich, NR4 7UG, UK
| | - Cécile Raynaud
- Institute of Plant Sciences Paris of Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Orsay, France
| | - David Latrasse
- Institute of Plant Sciences Paris of Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Orsay, France
| | - Moussa Benhamed
- Institute of Plant Sciences Paris of Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Orsay, France.
- Institut Universitaire de France (IUF), Paris, France.
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Stevens R, Grelon M, Vezon D, Oh J, Meyer P, Perennes C, Domenichini S, Bergounioux C. A CDC45 homolog in Arabidopsis is essential for meiosis, as shown by RNA interference-induced gene silencing. Plant Cell 2004; 16:99-113. [PMID: 14660803 PMCID: PMC301398 DOI: 10.1105/tpc.016865] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2003] [Accepted: 10/04/2003] [Indexed: 05/17/2023]
Abstract
CDC45 is required for the initiation of DNA replication in yeast and cell proliferation in mammals and functions as a DNA polymerase alpha loading factor in Xenopus. We have cloned a CDC45 homolog from Arabidopsis whose expression is upregulated at the G1/S transition and in young meiotic flower buds. One-third of Arabidopsis 35S:CDC45 T1 RNA interference lines are partially to completely sterile, and the proportion of sterile plants is increased by using a dmc1 promoter. T1 plants have decreased levels of the CDC45 transcript and contain 21- to 23-bp RNA fragments specific to the CDC45 gene. T2 transgenic lines, in which small RNA fragments are still present, were used to analyze S-phase entry by 5-bromodeoxyuridine incorporation, which was not altered compared with that in the wild type. However, microarray data show that other cell cycle genes are upregulated or downregulated. T2 plants also have highly reduced fertility. The severity of the phenotype is correlated with the levels of the CDC45 transcript and small RNA fragments. Severe chromosome fragmentation arising during meiosis, which is not the result of a defect in the repair of SPO11-induced double strand breaks, leads to abnormal chromosome segregation and defective pollen and ovule development.
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Affiliation(s)
- Rebecca Stevens
- Institut de Biotechnologie des Plantes, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8618, Université de Paris-Sud, 91405 Orsay, France.
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