Cytochrome P450 Mining for Bufadienolide Diversification.

Bufadienolides are a class of steroids with a distinctive α-pyrone ring at C17, mostly produced by toads and consisting of over 100 orthologues. They exhibit potent cardiotonic and antitumor activities and are active ingredients of the traditional Chinese medicine Chansu and Cinobufacini. Direct extraction from toads is costly, and chemical synthesis is difficult, limiting the accessibility of active bufadienolides with diverse modifications and trace content.

Self-Assembled Saccharide-Functionalized Amphiphilic Metallacycles as Biofilms Inhibitor via "Sweet Talking".

Bacterial biofilms are troublesome in the treatment of bacterial infectious diseases due to their inherent resistance to antibiotic therapy. Exploration of alternative antibiofilm reagents provides opportunities to achieve highly effective treatments. Herein, we propose a strategy to employ self-assembled saccharide-functionalized amphiphilic metallacycles (, , and ) with multiple positive charges as a different type of antibacterial reagent, marrying saccharide functionalization that interact with bacteria via "sweet talking".

Efficient circular gene knockout system for Burkholderiales strain DSM 7029 and Mycobacterium smegmatis mc2 155.

Multiple gene knockouts are often employed in studies of microbial physiology and genetics. However, the selective markers that confer antibiotic resistance are generally limited, so it is necessary to remove these resistance genes before the next round of using, which is time consuming and labor intensive. Here, we created a universal circular gene knockout system for both the gram-negative bacterial Burkholderiales strain DSM 7029 and the gram-positive bacterial Mycobacterium smegmatis mc2 155, by combining the homologous recombination with multiple serine integrase-meditated site-specific recombination systems.

Site-specificity of serine integrase demonstrated by the attB sequence preference of ɸBT1 integrase.

Serine integrases mediate site-specific recombination and are extensively applied in genetic engineering and synthetic biology. However, which regions of the attachment sites determine site-specificity and how these regions function in recombination remain elusive. Here, we explored the sequence features of attB attachment sites recognized by ɸBT1 integrase, a representative serine integrase.

Bxb1 integrase serves as a highly efficient DNA recombinase in rapid metabolite pathway assembly.

Phage-encoded serine integrases are widely used in genetic engineering. They also have the potential to serve as efficient DNA assemblers, demonstrated by the method of site-specific recombination-based tandem assembly (SSRTA) that can combine biological parts into devices, pathways, and systems. Here, four serine integrases, ϕBT1, TG1, ϕRv1, and Bxb1, were investigated to ascertain their in vitro DNA assembly activities.