Molecular analysis of the adaptive response in Salmonella Typhimurium after starvation in salty conditions

Abstract

Introduction: The pathogenic bacterium Salmonella enterica serovar Typhimurium elicits a variety of genetic programs to adapt to stress conditions encountered within hostile environments such as host phagocytes and preserved food. Methodology: In this work, differential display (DD) methodology was used to investigate the effect of one month starvation in a salty microcosm (0.5 M NaCl) on transcript profiling in a Salmonella Typhimurium LT2 strain. cDNA fragments resulting from differentially expressed mRNA were eluted from the gel, re-amplified, cloned, and then sequenced. Results: A total of 21 differentially expressed bands were detected by DD reverse transcription-polymerase chain reaction (RT-PCR). However, only 12 of them were successfully identified as upregulated genes in stressed cells. Based on the sequencing data and BLAST analysis, these genes were sopA, ssaD, yhhK, gmK, cspC, uspA, ompR, phoP, stcC, fimA, acrA,and yehZ. As a confirmation of the differential expression, RT-PCR was carried out using a set of specific primers. Remarkably, the expression levels of these genes were significantly increased in starved bacteria compared to standard laboratory conditions. Conclusions: Our results indicate that the starvation of Salmonella Typhimurium over one month in a salty microcosm changes the expression of stress proteins, response regulator in a two-component system, outer membrane proteins, effector proteins translocated by Salmonella pathogenicity island SPI1 and SPI2 type III secretion systems (TTSS), several metabolic enzymes, efflux pumps, and transport proteins. This suggests that the expression of the identified genes is important for the response of this pathogen to starvation in salt.

Conserved ABC Transport System Regulated by the General Stress Response Pathways of Alpha- and Gammaproteobacteria

“…The primary structure of YehZ closely resembles known quaternary ammonium-compatible solute (osmoprotectant)-binding proteins, but our functional data for B. abortus ( Fig. 2 and 3) and published functional data on Yeh transporters of E. coli and S. enterica do not support a role for YehZ in osmoprotection (17)(18)(19)(20). We took a phylogenetic approach to evaluate whether YehZ proteins from E. coli (Protein Data Bank [PDB] ID 4WEP) (19), Agrobacterium tumefaciens (PDB ID 4NE4), and B. abortus form a distinct group among PBPs involved in osmolyte uptake (Fig.…”

“…The operon encodes a predicted ABC transporter. The PBP component of the operon (gene locus bab1_0226) is most closely related to Escherichia coli and Salmonella enterica YehZ, which has been described as a component of a putative compatible solute osmoprotectant transport system, YehZYXW (17)(18)(19)(20). The Yeh system is related in primary structure to the glycine betaine OsmU/ ProU uptake systems of S. enterica and E. coli and the OpuB/OpuC choline transporter of Bacillus subtilis (17,(20)(21)(22)(23).…”

Aplikasi Basic Local Alignment Search Tool (BLAST) NCBI Pada Penelitian Molekuler Salmonella SPP

“…Hasil penelusuran menggunakan kata kunci Salmonella dan BLAST, mesin pencarian jurnal Google Scholar dan PUBMED menemukan sebanyak masing-masing 26200 dan 32 artikel (Gambar 1) Fungsi 1 BLAST: Mengidentifikasi Sekuens Pencarian sekuens homolog menjadi langkah informatif pada analisis identifikasi organism (Elabed, Merghni, Hamza, Bakhrouf, & Gaddour, 2016). BLAST melakukan pencarian sekuens homolog dengan cara menyaring data sesuai dengan filter yang ditentukan untuk menemukan kemiripan sekuens pada database (Forslund, Pekkari, & Sonnhammer, 2011).…”

“…Berdasarkan jurnal yang telah di review, aplikasi penggunaan BLAST pada Salmonella dengan memanfaatkan fungsi BLAST yaitu menemukan DNA target dengan efisien dapat diaplikasikan untuk berbagai macam tujuan, seperti untuk mengembangkan metode deteksi Salmonella dengan menggunakan gen target spesifik (Rehman, Yin, Persaud-Lachhman, & Diarra, 2017), untuk menemukan gen yang bertanggung jawab (overexpression) pada Salmonella dengan kondisi lingkungan tertentu atau terpapar faktor stress untuk menemukan gen pada Salmonella yang memiliki karakteristik tertentu seperti ketahanan terhadap antimikroba atau antibiotic (Rinanda, 2011). Elabed et al (2016) melaporkan hasil BLAST bahwa gen yang bertanggung jawab pada kondisi stress kekurangan makanan dan salinitas tinggi pada Salmonella Typhimurium adalah gen sopA, ssaD, yhhK, gmK, cspC, uspA, ompR, phoP, stcC, fimA, acrA, andyehZ. Hennebry et al (Rosniawati, Rahayu, Kusumaningrum, Indrotristanto, & Nikastri, 2020).…”