Abstract
Escherichia coli O157:H7 EDL933 exposed to low-shear modeled microgravity (LSMMG) and normal gravity (NG) was used for a transcriptomic analysis. The modified Gompertz model (R2 = 0.81–0.99) showed an increased growth rate of E. coli O157:H7 under LSMMG. The mechanism of this active growth was associated with highly upregulated genes in nutrient and energy metabolism, including the TCA cycle, glycolysis, and pyruvate metabolism. Green fluorescent protein-labeled E. coli O157:H7 also formed significantly thick biofilms (fluorescent unit: NG, 1,263; LSMMG, 1,533; P = 0.0473) under LSMMG, whereas bacterial mobility decreased slightly (P = 0.0310). The transcriptomic analysis revealed that genes encoding glycogen biosynthesis (glgCAP operon) were upregulated (1.40 to 1.82 of log fold change [FC]) due to the downregulation of csrA (2.17 of log FC), which is the global regulator of biofilm formation of E. coli. We also identified 52 genes in E. coli O157:H7 EDL933 that were involved in the secretion pathway, 32 of which showed ≥2-fold significant changes in transcription levels after cultivation under LSMMG. Notably, all downregulated genes belonged to the type III and VI secretion systems, indicating that host cell contact secretion was dysregulated in the LSMMG cultures compared to the NG cultures. LSMMG also stimulates the pathogenicity of E. coli O157:H7 via transcriptional upregulation of Shiga toxin 1 (1.36 to 2.81 log FC) and toxin HokB (6.1 log FC). Our results suggest LSMMG affects bacterial growth, biofilm formation, and E. coli O157:H7 pathogenicity at some transcriptional levels, which indicates the importance of understanding biological consequences.
Original language | English |
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Article number | 111013 |
Journal | Food Research International |
Volume | 154 |
DOIs | |
Publication status | Published - 2022 Apr |
Bibliographical note
Funding Information:This research was supported by the Korea Research Foundation (NRF-2011-0012712). The authors thank the School of Life Sciences and Biotechnology of the Korea University for BK 21 PLUS, and the Institute of Biomedical Science and Food Safety, Korea University Food Safety Hall, for enabling access to their equipment and facilities.
Funding Information:
This research was supported by the Korea Research Foundation ( NRF-2011-0012712 ). The authors thank the School of Life Sciences and Biotechnology of the Korea University for BK 21 PLUS, and the Institute of Biomedical Science and Food Safety, Korea University Food Safety Hall, for enabling access to their equipment and facilities.
Publisher Copyright:
© 2022 Elsevier Ltd
ASJC Scopus subject areas
- Food Science