Phosphorus (P) plays an important role in regulating primary production in estuarine environments. However, knowledge of the P-functional gene composition of microbial communities and the mechanisms of microbial adaptation to changes in available P in estuaries remain limited. This study coupling 16 s rDNA and metagenomics sequencing was conducted to reveal the relationship between P cycling functional genes, microbial interactions, and P availability in the Jiulong River Estuary. The results showed that the relative abundance of P cycling functions genes was highest in winter, and lowest in summer. Spatially, the total relative abundance of P cycling functions genes was higher in the riverward than that in the seaward. P cycling functional microbial interactions and P cycling gene coupling were strongest in summer and in the seaward. Changes in both temperature and salinity had significant direct and indirect effects on P cycling function, and the influence of salinity on P cycling function was greater than that on the microbial community in the estuary. Salinity had significant direct negative effects on inorganic P-solubilization (IP), organic P-mineralization (OP), and P uptake and transport functions (PT). Whereas, salinity had a significant positive effect on P-starvation response regulation (PR) function. Thus, salinity and microbial communities regulate the soluble reactive phosphate concentrations in estuarine environments by strengthening internal coupling among P cycling functions, promoting PR function, and facilitating PT gene expression. PR is the most important predictors, PR, PT, and PR-PT together explained 38.56 % of the overall soluble reactive phosphorus (SRP) variation. Over 66 % of the explained SRP variations can be predicted by the PR, PT, and PR-PT functional genes. This finding improves the knowledge base of the microbial processes for P cycling and provides a foundation for eutrophication management strategies in the estuary.
Hypoxia-inducible factors(HIFs)are the key transcription factors that sense and regulate cellular oxygen concentration in vivo. HIF-1 is composed of 2 subunits,α and β,in which,the molecular regulatory mechanism of HIF-1α involves the main processes of its degradation and activation. The degradation of HIF-1α is regulated by oxygen-dependent pathways,including "von hippel-lindau protein(pVHL)-dependent pathway" and "pVHL-independent pathway". The activation of HIF-1α is regulated by oxygen-independent pathways,including mammalian target of rapamycin(mTOR)/eukaryotic initiation factor 4 E-binding protein 1(4 EBP1)/HIF-1α pathway,phosphatidylinositol 3-kinase(PI3 K)/proteirrserinc-threonine kinases(Akt)/HIF-1α pathway and silent information regulator1(Sirt1)/HIF-1α pathway. In recent years,based on the molecular regulatory mechanism of HIFs,Roxadustat,a new drug for the treatment of renal anemia has been developed. Besides, some macromolecular substances with similar pharmacological effect to HIFs have been found in the extracts from Chinese herbal medicine(CHM),such as emodin,notoginseng triterpenes,honokiol and clematichinenoside. These natural macromolecular substances play the regulatory roles in inflammatory response,epigenetic modification and auto-phagy. It is worth noting that,for common hypoxic-related diseases including diabetic kidney disease,HIFs-mediated "pyroptosis" may be a new target of CHMs for clearing dampness and heat and its representative classical prescriptions(Ermiao Pills)in treating inflammatory injury in cells and tissues.