Efficient production of butyric acid from lignocellulosic biomass by revealing the mechanisms of Clostridium tyrobutyricum tolerance to phenolic inhibitors.

Phenolic compounds (PCs) generated during pretreatment of lignocellulosic biomass severely hinder the biorefinery by Clostridia. As a hyperbutyrate-producing strain, Clostridium tyrobutyricum has excellent tolerance to PCs, but its tolerance mechanism is poorly understood. In this study, a comprehensive transcriptome analysis was applied to elucidate the response of C. tyrobutyricum to four typical PCs. The findings revealed that the expression levels of genes associated with PC reduction, HSPs, and membrane transport were significantly altered under PC stress. Due to PCs being reduced to low-toxicity alcohols/acids by C. tyrobutyricum, enhancing the reduction of PCs by overexpressing reductase genes could enhance the strain's tolerance to PCs. Under 1.0 g/L p-coumaric acid stress, compared with the wild-type strain, ATCC 25755/sdr1 exhibited a 31.2 % increase in butyrate production and a 38.5 % increase in productivity. These insights contribute to the construction of PC-tolerant Clostridia, which holds promise for improving biofuel and chemical production from lignocellulosic biomass.

Expert consensus on the clinical application of totally implantable venous access devices in the upper arm (2022 Edition).

With the widespread adoption of ultrasound guidance, Seldinger puncture techniques, and intracardiac electrical positioning technology for the placement of peripherally inserted central catheters in recent years, an increasing number of medical staff and patients now accept peripheral placement of totally implantable venous access devices (TIVADs) in the upper arm. This approach has the advantage of completely avoiding the risks of hemothorax, pneumothorax, and neck and chest scarring. Medical specialties presently engaged in this study in China include internal medicine, surgery, anesthesiology, and interventional departments. However, command over implantation techniques, treatment of complications, and proper use and maintenance of TIVAD remain uneven among different medical units. Moreover, currently, there are no established quality control standards for implantation techniques or specifications for handling complications. Thus, this expert consensus is proposed to improve the success rate of TIVAD implantation via the upper-arm approach, reduce complication rates, and ensure patient safety. This consensus elaborates on the technical indications and contraindications, procedures and technical points, treatment of complications, and the use and maintenance of upper-arm TIVAD, thus providing a practical reference for medical staff.

Baicalein inhibits MMP-2 expression in human ovarian cancer cells by suppressing the p38 MAPK-dependent NF-κB signaling pathway.

Matrix metalloproteinases (MMPs) secreted by ovarian cancer play essential roles in tumor invasion and metastasis. In this study, we investigated the effect of baicalein, which is isolated from the traditional Chinese herbal medicine Scutellaria baicalensis Georgi, on human ovarian cancer cell lines by measuring MMP-2 expression, invasive potential, and the underlying molecular mechanisms. Analysis of MMP-2 was carried out by western blots and RT-PCR. The invasion ability of ovarian cancer cells was determined using a Transwell invasion assay. Nuclear factor-κB (NF-κB) and p38 MAPK activation was assessed by western blots. The results of the present study showed that baicalein reduced the expression of MMP-2 in a dose-dependent manner and the invasion of ovarian cancer cells was also significantly suppressed by baicalein. We also found that baicalein reduced the activation of NF-κB signaling molecules; in addition, the MMP-2 expression and invasion ability of ovarian cancer cells were abolished with the treatment of the NF-κB inhibitor, pyrrolidine dithiocarbamate. However, the addition of p38 MAPK inhibitor SB203580 significantly reduced the activation of NF-κB; meanwhile, baicalein was shown to exert an inhibitory effect on p38 activation. Furthermore, the MMP-2 expression and invasion ability of ovarian cancer cells were significantly inhibited by SB203580. In conclusion, baicalein inhibits the MMP-2 expression and invasion ability of ovarian cancer cells, possibly by the p38 MAPK-dependent NF-κB signaling pathway; these findings may provide insights into the potential of using baicalein as a therapeutic strategy against ovarian cancer.