ABSTRACT Talaromyces marneffei is a thermally dimorphic fungus causing life-threatening systemic mycosis in immunocompromised patients. The emergence of azole-resistant clinical isolates, especially those with reduced susceptibility to voriconazole (VOC) and fluconazole (FLC), presents a critical therapeutic challenge. Although target-gene alterations and efflux-related mechanisms have been reported in pathogenic fungi, the broader molecular basis distinguishing high-minimum-inhibitory concentration (MIC) and low-MIC T. marneffei clinical isolates remains incompletely defined. Here, we performed integrated transcriptomic (RNA-seq), proteomic (DIA-LC-MS/MS), and RT-qPCR analyses comparing four resistant and four susceptible T. marneffei clinical isolates. Differentially expressed genes and proteins were identified, functionally interpreted, and integrated to prioritize resistance-associated molecular candidates. The multi-omics results supported a constitutive, multitiered resistance-associated state involving transport and cell wall processes, redox-detoxification, mitochondrial metabolism, and stress regulatory adaptation. Signals involving coilin, CatA, and other discriminant features contributed to the multi-omics prioritization layer. RT-qPCR supported a 17-gene panel associated with transport, redox-detoxification, mitochondrial metabolism, and stress regulation. Five genes, PMAA_008970, PMAA_058960, PMAA_070510, PMAA_088690, and PMAA_092180, showed statistically significant R/S differences, while the remaining panel members were detectable and trend-supporting within the same functional framework. These findings refine a hierarchical azole-resistance model in T. marneffei and provide a focused candidate panel for future mechanistic validation.
Yanqing Zheng, Gao-Yuan Peng, Xiao-Feng Pang et al.· Antimicrobial Agents and Che...· 0 citations
The Type VI secretion system (T6SS) is a key nanoweapon in Gram-negative bacteria that mediates microbial competition and pathogenesis via toxic effector delivery. Three functionally distinct T6SS clusters (H1-H3) are known in Pseudomonas aeruginosa, yet the broader evolutionary diversity and regulatory networks of T6SS in this pathogen remain poorly defined. Here, we identify Sfa4, a transcriptional regulator linked to a fourth T6SS (H4-T6SS) in clinical isolate LYSZa7. Sfa4 directly binds amrZ and H4-T6SS cluster to activate their transcription. AmrZ, in turn, directly regulates all four T6SS clusters. We further show that c-di-GMP receptor FleQ directly binds the promoters of all four T6SS clusters, revealing a direct regulatory link between c-di-GMP signaling and T6SS transcription. This regulation, together with Sfa4-mediated elevation of intracellular c-di-GMP levels, coordinately enhances H4-T6SS activity, biofilm formation, and virulence in A549 alveolar epithelial cells and Galleria mellonella models. Phylogenetic analysis shows Sfa4 homologs are present in Gram-negative bacteria, implying a potential T6SS-regulatory function. Collectively, our findings shed light on regulatory cascades and provide a mechanistic basis for understanding how clinically acquired T6SS clusters may be integrated into existing virulence networks.
Yizhou Zhang, T. Ye, Jie Deng et al.· International Journal of Bio...· 0 citations
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