Aspergillus fumigatus is an opportunistic pathogen threatening human health, but the function of its ipi1 gene remains unclear. An ipi1 deletion strain (Δipi1), a complemented strain (Δipi1::ipi1+), and an overexpression strain (ipi1-OE) were constructed by homologous recombination. The phenotypic characteristics, stress responses, antioxidant enzyme activities, reactive oxygen species (ROS) levels, mitochondrial membrane potential (MMP), and transcriptomic profiles were analyzed. Larval mortality was recorded in the Galleria mellonella infection model and analyzed by survival analysis. Compared with the wild-type strain (WT), both the Δipi1 and ipi1-OE strains exhibited slower growth and altered responses to oxidative and osmotic stress. The Δipi1 strain exhibited increased sporulation density and abnormal hyphal morphology, and was associated with more rapid larval mortality. The ipi1-OE strain exhibited transiently increased sporulation density and fewer conidial heads and was associated with lower larval mortality. Both mutants exhibited decreased T-SOD and CAT activities, elevated ROS levels, reduced MMP, and altered transcript levels of genes involved in transmembrane transport and metabolism. Conclusions: ipi1 plays an important role in growth, stress responses, antioxidant defense, mitochondrial function, and sporulation in A. fumigatus, and its deletion or overexpression is associated with altered larval mortality in the G. mellonella infection model.
In Northeast China, long-term large-scale monoculture farming has caused a decrease in soil nutrients. To maintain crop yields, excessive amounts of chemical fertilizers are frequently used, resulting in multiple problems. In recent years, diversified cropping systems (such as corn–soybean rotation) have been increasingly introduced into Northeast China to help preserve soil nutrients. Additionally, conservation tillage methods (such as straw return) have been widely adopted in Chinese agriculture to enhance soil fertility and reduce chemical fertilizer application. However, the characteristics of soil phosphorus cycling under combined agricultural practices are yet to be fully clarified, not to mention the mechanism of P cycling enzyme changes driven by soil functional microorganisms. Therefore, this study investigated the impact of straw return combined with fertilizer reduction from a field experiment on soil phosphatase activity and the phoC gene characteristics. The results of the field experiment show that straw return combined with fertilizer reduction based on the maize–soybean rotation system exhibited no significant effects on the contents of soil organic matter, total phosphorus and other nutrients (with declines of less than 10%), indicating that soil nutrient status was well maintained. Organic material addition also increased soil phosphatase activity and phosphatase functional gene abundance, significantly improving their diversity and community structure. Linear regression results show that the variation in phoC gene abundance is an important molecular mechanism driving the differences in soil phosphatase activity under various agronomic methods. Our results offer important guidance for implementing effective strategies to reduce fertilizer use in agricultural practices in Northeast China.
Cyanobacterial blooms are a widespread concern in freshwater ecosystems worldwide because of their impacts on water quality, ecosystem functioning, and human health. Bloom-forming cyanobacteria such as Microcystis coexist with diverse bacterial assemblages whose metabolic capabilities may contribute to the organization of the bloom-associated microbial environment, yet these traits remain comparatively understudied at genome resolution, particularly in South American freshwater systems. Here, we characterized a microbial community recovered after laboratory enrichment of Microcystis-dominated cyanobacterial biomass recovered from the El Loto urban wetland in southern Chile, using high-throughput DNA sequencing, co-assembly, and genome-resolved metabolic reconstruction. Five independent enrichments yielded 40 metagenome-assembled genomes (MAGs) across seven bacterial phyla, of which 19 (>90% completeness, <5% contamination) were retained for metabolic reconstruction. Pathway predictions were evaluated against pathway-specific diagnostic genes. Central carbon and respiratory functions were broadly represented, whereas carbon fixation, phototrophy, and nutrient-related traits showed more restricted, lineage-associated distributions. The Calvin–Benson–Bassham cycle was supported in four MAGs, while alternative carbon-fixation pathways lacked diagnostic-gene support. Oxygenic photosynthetic machinery was restricted to the two Cyanobacteriota MAGs, whereas seven Pseudomonadota encoded syntenic gene clusters consistent with anoxygenic phototrophic potential. Nitrogen fixation and canonical ammonia oxidation were not represented among the retained MAGs, although associated genes were detected in the community gene catalogue. Phosphonate-related traits were also unevenly distributed, with phnJ and the associated C–P lyase system detected in five Pseudomonadota MAGs, while phosphonate transport-related genes occurred more broadly. Taken together, these results reveal a broadly shared core metabolic repertoire alongside a more restricted, lineage-associated distribution of other metabolic traits within the enrichment-derived microbial community.
Reassortment between the 2009 pandemic H1N1 virus (pdm/09) and endemic swine influenza viruses has generated zoonotic viruses, including A/Swine/Guangxi/NS2783/2010 (H3N2; SW2783). How host microRNAs shape the outcome of such transmission remains poorly defined. We combined iTRAQ-based quantitative proteomics of A549 cells infected with SW2783, the classical swine H1N1 virus SW3861, or the pdm/09 strain CA09 with our previous miRNA-mRNA dataset. Among 2398 proteins consistently quantified, an integrative analysis identified 118 candidate proteins (49, downregulated and 69 upregulated), of which eight, including PPIA and IFIT2, were prioritized as potential virus-response factors. Western blotting showed that RPS29, HMGA2, IFIT2, and PPIA were specifically upregulated in SW2783-infected cells. miR-140-5p reduced nPPIA and IFIT2 protein levels, and dual-luciferase assays supported direct regulation of the IFIT2 3′ UTR, whereas PPIA appeared to be regulated indirectly. Overexpression of miR-140-5p increased SW2783 M-gene transcripts, HA titers, and TCID50 values (p < 0.01) but did not affect replication of SW3861 or CA09. Together, these findings suggest that miR-140-5p promotes replication of the zoonotic reassortant swine H3N2 virus SW2783, at least in part through direct suppression of IFIT2, while its effect on PPIA appears to be indirect. These results identify the miR-140-5p/IFIT2 axis as a potential host regulatory pathway associated with replication of reassortant swine influenza viruses and warrant further investigation of its relevance to zoonotic risk.
