Changes in Vibrio natriegens Growth Under Simulated Microgravity

Area of Science:

• Microbiology
• Genomics
• Biophysics

Background:

• Bacterial growth rates can be influenced by environmental factors like simulated microgravity (SMG).
• Vibrio natriegens is a fast-growing bacterium, making it a model for studying rapid growth.
• Long-term SMG culturing aimed to enhance V. natriegens growth but resulted in a slower-growing mutant.

Purpose of the Study:

• To investigate the molecular mechanisms behind the slower growth rate of a V. natriegens mutant under SMG.
• To gain insights into the genetic and structural basis of rapid bacterial growth.

Main Methods:

• Multi-omics integration analysis (transcriptomics, Hi-C, whole genome re-sequencing).
• Long-term continuous culturing of V. natriegens under simulated microgravity.
• Comparative analysis of a slower-growing mutant against the wild type (WT).

Main Results:

• Transcriptome analysis showed differential gene expression, with up-regulation in mechanical signal transduction and flagellin biogenesis, and down-regulation in adaptive responses, metabolism, and cell vitality.
• Genome-wide chromosome conformation capture (Hi-C) revealed SMG-induced 3D genome organization changes correlated with differentially expressed genes (DEGs).
• Whole genome re-sequencing identified structure variations (SVs) in regions with low interaction frequency and down-regulated genes, potentially indicating prophage regions and affecting chromosome replication.

Conclusions:

• Simulated microgravity influences V. natriegens growth rate by altering 3D genome organization and gene expression.
• Changes in genome conformation may be a mechanism for sensing stress and regulating genes involved in flagellin, adaptability, and chromosome segregation.
• These alterations affect physiological characteristics, impacting growth rate and metabolic capacity.