García Katherine, Yáñez Cristian, Plaza Nicolás, Peña Francisca, Sepúlveda Pedro, Pérez-Reytor Diliana, Espejo Romilio T
Centro de Investigación Biomédica, Facultad de Ciencias de la Salud, Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Av. El Llano Subercaseaux, 2801, Santiago, Chile.
Institute of Nutrition and Food Technology, Universidad de Chile, Av. El Líbano 5524, Macul, Santiago, Chile.
BMC Microbiol. 2017 May 19;17(1):118. doi: 10.1186/s12866-017-1030-6.
Vibrio parahaemolyticus is an autochthonous marine bacterial species comprising strains able to grow in broth containing bile salts at 37 °C, a condition seldom found in the ocean. However, this condition is used for isolation in the laboratory because it is considered a necessary property for pathogenesis. In this context, revealing how gene expression enables V. parahaemolyticus to adapt to this particular condition -common to almost all V. parahaemolyticus isolates- will improve our understanding of the biology of this important pathogen. To determine the genes of V. parahaemolyticus differentially expressed when growing in isolation condition (37 °C, 0.9% NaCl, and 0.04% bile salts) referred to those at the temperature and salt concentration prevailing in ocean south of Chile (marine-like condition; 12 °C, 3% NaCl, and absence of bile salts) we used high-throughput sequencing of RNA.
Our results showed that in the isolation condition, among the 5034 genes annotated in the V. parahaemolyticus RIMD2210633 genome, 344 were upregulated and 433 downregulated referred to the marine-like condition, managing an adjusted P-value (Padj) < E. Between the 50 more highly expressed genes, among the small RNAs (sRNA), the three carbon storage regulators B (CsrB) were up four to six times, while RyhB, related to iron metabolism besides motility control, was down about eight times. Among proteins, BfdA, a hemolysin-co-regulated protein (Hcp1) secreted by T6SS1, one of the most highly expressed genes, was about 140 times downregulated in isolation condition. The highest changes in relative expression were found among neighboring genes coding for proteins related to respiration, which were about 40 times upregulated.
When V. parahaemolyticus is grown in conditions used for laboratory isolation 777 genes are up- or downregulated referred to conditions prevailing in the marine-like condition; the most significantly overrepresented categories among upregulated processes were those related to transport and localization, while secretion and pathogenesis were overrepresented among downregulated genes. Genes with the highest differential expression included the sRNAs CsrB and RhyB and the mRNAs related with secretion, nutritional upshift, respiration and rapid growing.
副溶血性弧菌是一种本地海洋细菌物种，其菌株能够在含有胆盐的肉汤中于37°C生长，而这种条件在海洋中很少见。然而，这种条件在实验室中用于分离，因为它被认为是致病的必要特性。在这种情况下，揭示基因表达如何使副溶血性弧菌适应这种几乎所有副溶血性弧菌分离株都共有的特殊条件，将增进我们对这种重要病原体生物学特性的理解。为了确定副溶血性弧菌在分离条件下（37°C、0.9%氯化钠和0.04%胆盐）生长时差异表达的基因，与在智利南部海洋中普遍存在的温度和盐浓度条件下（类海洋条件；12°C、3%氯化钠且无胆盐）的基因相比，我们使用了RNA高通量测序。
我们的结果表明，在分离条件下，在副溶血性弧菌RIMD2210633基因组中注释的5034个基因中，与类海洋条件相比，有344个基因上调，433个基因下调，调整后的P值（Padj）<E。在50个表达量更高的基因中，在小RNA（sRNA）中，三个碳储存调节因子B（CsrB）上调了四到六倍，而除了运动控制外还与铁代谢相关的RyhB下调了约八倍。在蛋白质中，T6SS1分泌的溶血素共调节蛋白（Hcp1）BfdA是表达量最高的基因之一，在分离条件下下调了约140倍。在编码与呼吸相关蛋白质的相邻基因中发现相对表达变化最大，上调了约40倍。
当副溶血性弧菌在实验室分离所用条件下生长时，与类海洋条件下的基因相比，有777个基因上调或下调；上调过程中最显著富集的类别是与转运和定位相关的类别，而下调基因中分泌和致病相关的类别富集。差异表达最高的基因包括sRNA CsrB和RhyB以及与分泌、营养上调、呼吸和快速生长相关的mRNA。
