Biology subjects

Meijler, M. M.

Publications and source records attributed to Meijler, M. M..

5 recordsLinked to original sources

bioRxiv2026

A phage communication peptide alters Bacillus subtilis colony development and promotes sporulation

Temperate Bacillus phages use arbitrium peptides to coordinate lysis-lysogeny decisions, but whether the mature communication peptide can be sensed directly by Bacillus subtilis and affect its physiology and behavior is unknown. Here we show that the {varphi}3T arbitrium peptide SAIRGA elicits a sequence- and stereochemistry-dependent response in Bacillus subtilis that is strongly expressed in surface-grown colony biofilms but is not accompanied by comparable changes in planktonic growth or static-liquid pellicle morphology. The response persists in the absence of AimR, the canonical arbitrium receptor. Within colonies, SAIRGA alters spatial PtapA activity and increases heat-resistant spore formation without increasing total viable cell yield. Untargeted metabolomics reveals broad dose-dependent remodeling that tracks peptide activity, while program-level proteomics independently converges on late-sporulation and mature-spore-associated states. This study highlights how a phage-derived peptide may act as a signal, enabling the host to pivot toward a survival-focused developmental state.

microbiology↗

bioRxiv2025

Chemical Crosstalk between the Common Soil Bacteria Pseudomonas chlororaphis and Bacillus subtilis

Chemical conversations between soil inhabitants are of tremendous importance to the health of many ecosystems, and at the same time detailed molecular knowledge underlying these conversations is surprisingly scarce. One of the major bacterial genera inhabiting the rhizosphere is Pseudomonas, of which most species are known to produce phenazines, which carry antibiotic properties. Pseudomonas chlororaphis, a common rhizosphere dwelling species with plant growth-promoting traits, produces phenazine-1-carboxamide (PCN). This study examines how the production of PCN by Pseudomonas affects another common species in soil that it often encounters, namely Bacillus subtilis. When both species were cultured at close distance, distinct and visible changes in colony morphologies were observed with-out changes in growth rates. Interestingly, a clear transformation occurred in the morphology of B. subtilis colonies in the presence of supplemented PCN, indicating the role of phenazines in affecting colony morphology. In addition, untargeted metabolomics analyses showed a decrease in the production of plipastatin and surfactin by B. subtilis in the presence of P. chlororaphis. Our results indicate that PCN induces changes in morphology and signaling of B. subtilis without significantly affecting its growth. We hypothesize that P. chlororaphis and B. subtilis sense one another and act to conserve energy while avoiding competition.

microbiology↗

bioRxiv2023

Metabolic rewiring of the probiotic bacterium Lacticaseibacillus rhamnosus GG contributes to cell wall remodeling and antimicrobials production

Lacticaseibacillus rhamnosus GG (LGG) is a Gram-positive beneficial bacterium that resides in the human intestinal tract and belongs to the family of lactic acid bacteria (LAB). This bacterium is a widely used probiotic and was suggested to provide numerous benefits for human health. However, as in most LAB strains, the molecular mechanisms that mediate the competitiveness of probiotics under different diets remain unknown. Fermentation is a fundamental process in LAB, allowing the oxidation of simple carbohydrates (e.g., glucose, mannose) for energy production under conditions of oxygen limitation, as in the human gut. Our results indicate that fermentation reshapes the metabolome, volatilome, and proteome architecture in LGG. Furthermore, fermentation alters cell envelope remodeling and peptidoglycan biosynthesis, which leads to altered cell wall thickness, aggregation properties, and cell wall composition. In addition, fermentable sugars induced secretion of known and novel metabolites and proteins targeting the enteric pathogens Enterococcus faecalis and Salmonella Enterica serovar Typhimurium. Overall, our results link the common metabolic regulation of cell wall remodeling, aggregation to host tissues, biofilm formation in probiotic strains, and connect the production of antimicrobial effectors with metabolome reprogramming. These findings provide novel insights into the role of nutrition in the establishment of LGG in the gastrointestinal tract.

microbiology↗

bioRxiv2021

GNPS Dashboard: Collaborative Analysis of Mass Spectrometry Data in the Web Browser

Access to web-based platforms has enabled scientists to perform research remotely. A critical aspect of mass spectrometry data analysis is the inspection, analysis, and visualization of the raw data to validate data quality and confirm statistical observations. We developed the GNPS Dashboard, a web-based data visualization tool, to facilitate synchronous collaborative inspection, visualization, and analysis of private and public mass spectrometry data remotely.

bioinformatics↗

bioRxiv2020

Algorithmic Learning for Auto-deconvolution of GC-MS Data to Enable Molecular Networking within GNPS.

Gas chromatography-mass spectrometry (GC-MS) represents an analytical technique with significant practical societal impact. Spectral deconvolution is an essential step for interpreting GC-MS data. No public GC-MS repositories that also enable repository-scale analysis exist, in part because deconvolution requires significant user input. We therefore engineered a scalable machine learning workflow for the Global Natural Product Social Molecular Networking (GNPS) analysis platform to enable the mass spectrometry community to store, process, share, annotate, compare, and perform molecular networking of GC-MS data. The workflow performs auto-deconvolution of compound fragmentation patterns via unsupervised non-negative matrix factorization, using a Fast Fourier Transform-based strategy to overcome scalability limitations. We introduce a "balance score" that quantifies the reproducibility of fragmentation patterns across all samples. We demonstrate the utility of the platform with breathomics analysis applied to the early detection of oesophago-gastric cancer, and by creating the first molecular spatial map of the human volatilome.

bioinformatics↗