Hepatic cysteine sulphinic acid decarboxylase depletion and defective taurine metabolism in a rat partial nephrectomy model of chronic kidney disease.

BACKGROUND: Taurine depletion occurs in patients with end-stage chronic kidney disease (CKD). In contrast, in the absence of CKD, plasma taurine is reported to increase following dietary L-glutamine supplementation. This study tested the hypothesis that taurine biosynthesis decreases in a rat CKD model, but is rectified by L-glutamine supplementation. METHODS: CKD was induced by partial nephrectomy in male Sprague-Dawley rats, followed 2 weeks later by 2 weeks of 12% w/w L-glutamine supplemented diet (designated NxT) or control diet (NxC). Sham-operated control rats (S) received control diet. RESULTS: Taurine concentration in plasma, liver and skeletal muscle was not depleted, but steady-state urinary taurine excretion (a measure of whole-body taurine biosynthesis) was strongly suppressed (28.3 ± 8.7 in NxC rats versus 78.5 ± 7.6 µmol/24 h in S, P < 0.05), accompanied by reduced taurine clearance (NxC 0.14 ± 0.05 versus 0.70 ± 0.11 ml/min/Kg body weight in S, P < 0.05). Hepatic expression of mRNAs encoding key enzymes of taurine biosynthesis (cysteine sulphinic acid decarboxylase (CSAD) and cysteine dioxygenase (CDO)) showed no statistically significant response to CKD (mean relative expression of CSAD and CDO in NxC versus S was 0.91 ± 0.18 and 0.87 ± 0.14 respectively). Expression of CDO protein was also unaffected. However, CSAD protein decreased strongly in NxC livers (45.0 ± 16.8% of that in S livers, P < 0.005). L-glutamine supplementation failed to rectify taurine biosynthesis or CSAD protein expression, but worsened CKD (proteinuria in NxT 12.5 ± 1.2 versus 6.7 ± 1.5 mg/24 h in NxC, P < 0.05). CONCLUSION: In CKD, hepatic CSAD is depleted and taurine biosynthesis impaired. This is important in view of taurine's reported protective effect against cardio-vascular disease - the leading cause of death in human CKD.

Analysis of Bacterial Flora Structure of Patients with Cerebral Hemorrhage Due to Hyperactivity of Liver-Yang by 16S rRNA Gene Sequencing Technique / 中国实验方剂学杂志

Objective: To explore the difference of intestinal flora between the patients with acute cerebral hemorrhage due to hyperactivity of liver-Yang and the healthy population. Method: The fecal samples of 9 patients with acute cerebral hemorrhage due to hyperactivity of liver-Yang from the first affiliated hospital of Guangzhou university of traditional Chinese medicine in 2018 were selected as observation group,and 6 stool samples from healthy subjects were selected as the control group.The total bacterial DNA was extracted from the two groups of samples,amplified according to the 16S rRNA V4 region,and paired-end sequencing was performed on the Illumina MiSeq platform.The sequencing results were analyzed by bioinformatics analysis software.The flora composition and structure of the samples from two groups were compared. Result:Venn analysis of operational taxonomic units(OTU) showed significant difference in OTU numbers between the observation group and control group.Partial least squares-discriminant analysis(PLS-DA) showed that there was a significant difference in the composition of intestinal flora between patients with acute cerebral hemorrhage and healthy subjects.On the analysis of species and abundance,at the classification level of phylum,compared with the control group,the ratio of relative abundance values of Firmicutes and Bacteroidetes(F/B) in the observation group was significantly increased,and the relative abundance of Verrucomicrobia was significantly decreased(PPrevotella,Bacteroides,Akkermansia,Blautia and Acidaminococcus(PPBacteroides and Prevotella(B/P) in the observation group was significantly higher than that of the control group;at the classification level of species,there were significant differences between the two groups in P. copri,A. muciniphila,B. ovatus,B. fragilis and Ruminococcus callidus(PPConclusion:Acute cerebral hemorrhage due to hyperactivity of liver-Yang is associated with structural disorder of intestinal flora,which is closely related to the decrease in relative abundance of P. copri and A. muciniphila.

Cloning, microbial expression and structure-activity relationship of polyphenol oxidases from Camellia sinensis.

Polyphenol oxidase (PPO) can be used for organic synthesis and degradation of wastes and dyes in industries. Lack of enzyme sources is a major barrier for its application. A PPO gene, with a full length of 1.8kb without introns, was cloned by PCR from genomic DNA of five common cultivars of Camellia sinensis. They had a 98.2-99.9% degree of identity in nucleotides and 94.7-96.1% in amino acids and encoded a polypeptide of 599 amino acids with a signal peptide targeting the chloroplast and three Cu-binding domains. The mature PPO showed high expression and enzyme activity after refolding the inclusion bodies in Escherichia coli BL21 (DE3) using pET30c expression vector, but low expression in Pichia pastoris GS115 using both the secretory and non-secretory vectors pPICZalphaA and pPICZA. The expression of PPO mutants demonstrated that the signal sequences prevented recombinant gene expression in E. coli. PPO activity was not affected by the C-terminus and was slightly inhibited by the CuC domain. Other domains were important for its activity. A 3.1-fold increase in PPO activity over non-recombinant controls was obtained by expressing the PPO fragment without signal sequences and the CuC domain in E. coli BL21 (DE3) using the pET30c vector.