The Protective Effect of Marsdenia tenacissima against Cisplatin-Induced Nephrotoxicity Mediated by Inhibiting Oxidative Stress, Inflammation, and Apoptosis.

Cisplatin (Cis) is considered to be one of the most effective drugs for killing cancer cells and remains a first-line chemotherapeutic agent. However, Cis's multiple toxicities (especially nephrotoxicity) have limited its clinical use. Marsdenia tenacissima (Roxb.) Wight et Arn. (MT), a traditional Chinese medicine (TCM) employed extensively in China, not only enhances the antitumor effect in combination with Cis, but is also used for its detoxifying effect, as it reduces the toxic side effects of chemotherapy drugs. The aim of this study was to explore the therapeutic effect of MT on Cis-induced nephrotoxicity, along with its underlying mechanisms. In this study, liquid-mass spectrometry was performed to identify the complex composition of the extracts of MT. In addition, we measured the renal function, antioxidant enzymes, and inflammatory cytokines in mice with Cis-induced nephrotoxicity and conducted renal histology evaluations to assess renal injury. The expressions of the proteins related to antioxidant, anti-inflammatory, and apoptotic markers in renal tissues was detected by Western blotting (WB). MT treatment improved the renal function, decreased the mRNA expression of the inflammatory factors, and increased the antioxidant enzyme activity in mice. A better renal histology was observed after MT treatment. Further, MT inhibited the expression of the phospho-NFκB p65 protein/NFκB p65 protein (p-p65)/p65, phospho-inhibitor of nuclear factor kappa B kinase beta subunit/inhibitor of nuclear factor kappa B kinase beta subunit (p-IKKß/IKKß), Bcl-2-associated X (Bax), and Cleaved Caspase 3/Caspase 3 proteins, while the expression of nuclear factor-erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), Recombinant NADH Dehydrogenase, Quinone 1 (NQO1), and B-cell lymphoma-2 (Bcl-2) was increased. The present study showed that MT ameliorated renal injury, which mainly occurs through the regulation of the Nrf2 pathway, the NF-κB pathway, and the suppression of renal tissue apoptosis. It also suggests that MT can be used as an adjuvant to mitigate the nephrotoxicity of Cis chemotherapy.

Response surface optimization of poly-ß-hydroxybutyrate synthesized by Bacillus cereus L17 using acetic acid as carbon source.

A strain of Bacillus that can tolerate 10 g/L acetic acid and use the volatile fatty acids produced by the hydrolysis and acidification of activated sludge to produce polyhydroxyalkanoate was screened from the activated sludge of propylene oxide saponification wastewater. The strain was identified by 16S rRNA sequencing and phylogenetic tree analysis and was named Bacillus cereus L17. Various characterization methods showed that the polymer synthesized by strain L17 is poly-ß-hydroxybutyrate, which has low crystallinity, good ductility and toughness, high thermal stability and a low polydispersity coefficient. It has wide thermoplastic material operating space as well as industrial and medicinal applications. The optimal fermentation conditions were determined by single factor optimization. Then, Plackett-Burman and Box-Behnken design experiments were carried out according to the single factor optimization results, and the response surface optimization was completed. The final results were: initial pH 6.7, temperature 25 °C, and loading volume 124 mL. The verification experiment showed that the yield of poly-ß-hydroxybutyrate after optimization increased by 35.2 % compared to that before optimization.

Production of polyhydroxyalkanoate by mixed cultivation of Brevundimonas diminuta R79 and Pseudomonas balearica R90.

The microflora in the activated sludge of propylene oxide saponification wastewater is characterized by a clear succession after enrichment and domestication, and the specifically enriched strains can significantly increase the yield of polyhydroxyalkanoate. In this study, Pseudomonas balearica R90 and Brevundimonas diminuta R79, which are dominant strain after domestication, were selected as models to examine the interactive mechanisms associated with the synthesis of polyhydroxyalkanoate by co-cultured strains. RNA-Seq analysis revealed the up-regulated expression of the acs and phaA genes of strains R79 and R90 in the co-culture group, which enhanced their utilization of acetic acid and synthesis of poly-ß-hydroxybutyrate. Cell dry weight and the yield of poly-ß-hydroxybutyrate in the co-culture group were accordingly considerably higher than those in the respective pure culture groups. In addition, two-component system, quorum-sensing, flagellar synthesis-related, and chemotaxis-related genes were enriched in strain R90, thereby indicating that compared with the R79 strain, R90 can adapt more rapidly to a domesticated environment. Expression of the acs gene was higher in R79 than in R90, and consequently, strain R79 could more efficiently assimilate acetate in the domesticated environment, and thus predominated in the culture population at the end of the fermentation period.