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Rohmer, C.

Publications and source records attributed to Rohmer, C..

2 recordsLinked to original sources

Automated evaluation of multiple sequence alignment methods to handle third generation sequencing errors

Most third-generation sequencing (TGS) processing tools rely on multiple sequence alignment (MSA) methods to manage sequencing errors. Despite the broad range of MSA approaches available, a limited selection of implementations are commonly used in practice for this type of application, and no comprehensive comparative assessment of existing tools has been under-taken to date. In this context, we have developed an automatic pipeline, named MSA_Limit, designed to facilitate the execution and evaluation of diverse MSA methods across a spectrum of conditions representative of TGS reads. MSA_Limit offers insights into alignment accuracy, time efficiency, and memory utilization. It serves as a valuable resource for both users and developers, aiding in the assessment of algorithmic performance and assisting users in selecting the most appropriate tool for their specific experimental settings. Through a series of experiments using real and simulated data, we demonstrate the value of such exploration. Our findings reveal that in certain scenarios, popular methods may not consistently exhibit optimal efficiency and that the choice of the most effective method varies depending on factors such as sequencing depth, genome characteristics, and read error patterns. MSA_Limit is open source is freely available at gitlab.cristal.univ-lille.fr/crohmer/msa-limit and all presented results and necessary information to reproduce the experiments are available at gitlab.cristal.univ-lille.fr/crohmer/msa-limit

bioinformatics↗

The capsular polysaccharide obstructs wall teichoic acid functions in Staphylococcus aureus

BackgroundThe cell envelope of Staphylococcus aureus contains two major secondary cell wall glycopolymers: capsular polysaccharide (CP) and wall teichoic acid (WTA). Both the CP and the WTA are attached to the cell wall and play distinct roles in S. aureus colonization, pathogenesis, and bacterial evasion of host immune defenses. ObjectiveWe aimed to investigate whether CP interferes with WTA-mediated properties. MethodsStrains with natural heterogeneous expression of CP, strains with homogeneous high CP expression and CP-deficient strains were compared to WTA deficient controls regarding WTA dependent phage binding, cell adhesion, IgG deposition, and virulence in vivo. ResultsWTA-mediated phage adsorption, specific antibody deposition and cell adhesion were negatively correlated with CP expression. WTA, but not CP, enhanced the bacterial burden in a mouse abscess model, while CP overexpression resulted in intermediate virulence in vivo. ConclusionsCP protects the bacteria from WTA-dependent opsonization and phage binding. This protection comes at the cost of diminished adhesion to host cells. The highly complex regulation and mostly heterogeneous expression of CP has probably evolved to ensure the survival and optimal physiological adaptation of the bacterial population as a whole.

microbiology↗