An improved extraction and nonradioactive thin-layer chromatography detection method of mycolic acid / 生物工程学报

Mycolic acids (MAs), i.e. 2-alkyl, 3-hydroxy long-chain fatty acids, are the hallmark of the cell envelope of Mycobacterium tuberculosis and are related with antibiotic resistance and host immune escape. Nowadays, they've become hot target of new anti-tuberculosis drugs. There are two main methods to detect MAs, 14C metabolic labeling thin-layer chromatography (TLC) and liquid chromatograph mass spectrometer (LC-MS). However, the user qualification of 14C or the lack of standards for LC-MS hampered the easy use of this method. TLC is a common way to analyze chemical substance and can be used to analyze MAs. In this study, we used tetrabutylammonium hydroxide and methyl iodide to hydrolyze and formylate MAs from mycobacterium cell wall. Subsequently, we used diethyl ether to extract methyl mycolate. By this method, we can easily extract and analyze MA in regular biological labs. The results demonstrated that this method could be used to compare MAs of different mycobacterium in different growth phases, MAs of mycobacteria treated by anti-tuberculosis drugs or MAs of mycobacterium mutants. Therefore, we can use this method as an initial validation for the changes of MAs in researches such as new drug screening without using radioisotope or when the standards are not available.

Apoptosis of lumbar spinal cord neurons in cauda equina syndrome rats / 药物分析学报

Objective To explore the law of apoptosis of lumbar spinal cord neurons in cauda equina syndrome (CES). Methods Cauda equina of rats was compressed by a piece of silica gel stick. From day 1 to day 28, the lumbar spinal cord specimens were harvested and assessed by Nissl's staining and TUNEL staining. Results Compression of cauda equina caused lesion and apoptosis of neurons in lumbar spinal cord, and the extent of apoptosis reached the peak on 7th day after compression. Conclusion Apoptosis of neurons in lumbar spinal cord might be one of the reasons why patients with CES get poor prognosis.