Interaction between orally administrated heparin and intestinal microbiota in mice / 生物工程学报

The development of orally administrated heparin drugs requires a systematic understanding of the interaction between heparin and gut flora. The in vivo distribution of fluorescein-labeled heparin that is orally administrated by mice was observed using fluorescein microscopy. In addition, the stability of heparin in simulated gastric and intestinal fluids, as well as the in vitro degradation of heparin by gut flora were detected by HPLC. The results show that orally administrated heparin was mainly distributed in the gastrointestinal tract of mice, and exerted structural stability under the condition of simulated gastric and intestinal fluids in vitro. However, heparin could be degraded by intestinal flora cultured in medium containing heparin. In order to further study the effect of orally administrated heparin on intestinal flora in mice, the fecal microbiota 16S rRNA fragment of C57BL/6J mice was tested by the Illumina Mi-Seq high-throughput sequencing technology. Compared with the gut flora of mice that orally administrated by saline, the biodiversity of gut flora in mice with orally administrated heparin was decreased. The difference of microflora structure was not significant at the phylum level, and the relative abundance of Alistipes, Parasutterella and Akkermansia was increased at the genus level, and the relative abundance of Bilophila, Enterorhabdus, Ruminiclostridium, Prevotellaceae_UCG_001, Ruminiclostridium-9, Bacteroides, Lachnoclostridium, Candidatus, Saccharimonas, Intestinimonas and Dubosiella was reduced. These findings indicate that heparin could influence the gut flora of mice. In addition, no obvious toxic and side effects were found in mice that orally administrated heparin, suggesting the safety of orally administrated heparin.

Kinetics of bioconversion of linoleic acid to conjugated linoleic acid by permeabilized Lactobacillus acidophilus cells / 生物工程学报

In this study, we analyzed the kinetics of bioconversion of conjugated linoleic acid (CLA) by permeabilized Lactobacillus acidophilus cells. The effects of cell mass, linoleic acid (LA) concentration, reaction pH and temperature on the bioconversion of CLA by permeabilized cells were investigated and the model system of bioconversion of CLA was established. The results showed that the production of CLA was increased by permeabilized cells. The optimal cell mass, pH and temperature of bioconversion of CLA were 10 x 10(10) ufc/mL, 4.5 and 45 degrees C, respectively. A marked LA inhibition phenomenon existed, and the early reaction rate of producing CLA reached the maximum (17.8 microg/mL x min) when LA concentration was 0.6 mg/mL. Michaelis constant was obtained by double-reciprocal plot and Hanes-Woolf plot. The reaction rate equation followed the classic Michaelis-Mentent equation at the low LA concentration, while there was a marked LA inhibition phenomenon at the high LA concentration. With the evaluated model parameters, the model system appeared to provide a description for the bioconversion of CLA by permeabilized Lactobacillus acidophilus cells.