Genetic research enables the evolution of novel biochemical reactions for the production of valuable chemicals from environmentally-friendly raw materials. However, the choice of appropriate microorganisms to support these reactions, which must have strong robustness and be capable of a significant product output, is a major difficulty. In the present study, the complete genome of the Clostridium tyrobutyricum strain CCTCC W428, a hydrogen- and butyric acid-producing bacterium with increased oxidative tolerance was analyzed. A total length of 3,011,209 bp of the C. tyrobutyricum genome with a GC content of 31.04% was assembled, and 3038 genes were discovered. Furthermore, a comparative clustering of proteins from C. tyrobutyricum CCTCC W428, C. acetobutylicum ATCC 824, and C. butyricum KNU-L09 was conducted. The results of genomic analysis indicate that butyric acid is produced by CCTCC W428 from butyryl-CoA through acetate reassimilation via CoA transferase, instead of the well-established phosphotransbutyrylase-butyrate kinase pathway. In addition, we identified ten proteins putatively involved in hydrogen production and 21 proteins associated with CRISPR systems, together with 358 ORFs related to ABC transporters and transcriptional regulators. Enzymes, such as oxidoreductases, HNH endonucleases, and catalase, were also found in this species. The genome sequence illustrates that C. tyrobutyricum has several desirable traits, and is expected to be suitable as a platform for the high-level production of bulk chemicals as well as bioenergy.
Targeting tumor markers is one of the most important approaches to tumor therapy, and the “suicide” pattern of tumor marker response is a very challenging study. Telomerase, as one of the key factors associated with human longevity and cancer progression, is considered to be an emerging biomarker for cancer diagnosis. The targeted drug delivery nanobomb─BIBR1532@HSN/FQDNA/MUC1 aptamer (B@HDA) is prepared in this study based on hollow silica nanoparticles (HSN) and CRISPR systems. Amino-modified FQDNA and amino-modified MUC1 aptamer are covalently attached to the surface of carboxyl-functionalized HSN. The modified MUC1 aptamer directs the nanobomb to specifically target breast cancer cells (MCF-7) and FQDNA sequesters the telomerase inhibitor (BIBR1532) within the HSN. Telomerase primers (TPs) is recognized by the highly expressed telomerase in MCF-7 cells and is elongated to form DNA substrates. The substrate pairs with crRNA bases to effectively activate CRISPR-Cas12a. The activated CRISPR-Cas12a precisely cut FQDNA, releasing BIBR1532, which inhibits telomerase activity. This strategy achieves telomerase “suicide”. The nanobomb described above has the following advantages. (1) The “closing” effect of FQDNA contributes to reducing the nonspecific release of BIBR1532. (2) B@HDA, combined with CRISPR, regulates mitochondrial dysfunction and cell senescence in MCF-7 cells. (3) In the tumor-bearing mouse model, B@HDA, combined with CRISPR, exhibits good biocompatibility and an obvious tumor ablation effect on MCF-7 tumors, suggesting potential application prospects across a wide range of cancer cell lines. In summary, the proposed nanobomb provides a tunable switch approach for the specific inhibition of telomerase and the reduction of tumor cell growth, representing a promising avenue for promoting senescence and treating cancer.
危险品化学品经营许可证（带存储）