FIGURE 7.

The proposed model for biological fitness mediated by malate in L. hongkongensis. Malate can be utilized as a sole carbon source and enhance the central metabolism, urease-mediated nitrogen metabolism, sulfate assimilation and respiratory metabolism. On the other hand, this process is precisely regulated by the transcription factor CRP, which can negatively balance this process by regulating other transcription factors (TFs) or target genes directly or indirectly, to form transcriptional regulatory networks and delicate feedback loop, thereby finely monitoring bacterial adaptation to various stresses.