Discrete genetic loci in human gut Bacteroides thetaiotaomicron confer pectin metabolism.

Although the polysaccharide utilization loci (PULs) activated by pectin have been defined, due to the complex of side-chain structure, the degradative mechanisms still remain vague. Thus, we hypothesize that there may have other specific PULs to target pectin. Here, we characterize loci-encoded proteins expressed by Bacteroides thetaiotaomicron (BT) that are involved in the pectin capturing, importation, de-branching and degradation into monosaccharides. Totally, four PULs contain ten enzymes and four glycan binding proteins which including a novel surface enzyme and a surface glycan binding protein are identified. Notably, PUL2 and PUL3 have not been reported so far. Further, we show that the degradation products support the growth of other Bacteroides spp. and probiotics. In addition, genes involved in this process are conservative in other Bacteroides spp. Our results further highlight the contribution of Bacteroides spp. to metabolism the pectic network.

Construction of a small-caliber tissue-engineered blood vessel using icariin-loaded ß-cyclodextrin sulfate for in situ anticoagulation and endothelialization.

The rapid endothelialization of tissue-engineered blood vessels (TEBVs) can effectively prevent thrombosis and inhibit intimal hyperplasia. The traditional Chinese medicine ingredient icariin is highly promising for the treatment of cardiovascular diseases. ß-cyclodextrin sulfate is a type of hollow molecule that has good biocompatibility and anticoagulation properties and exhibits a sustained release of icariin. We studied whether icariin-loaded ß-cyclodextrin sulfate can promote the endothelialization of TEBVs. The experimental results showed that icariin could significantly promote the proliferation and migration of endothelial progenitor cells; at the same time, icariin could promote the migration of rat vascular endothelial cells (RAVECs). Subsequently, we used an electrostatic force to modify the surface of the TEBVs with icariin-loaded ß-cyclodextrin sulfate, and these vessels were implanted into the rat common carotid artery. After 3 months, micro-CT results showed that the TEBVs modified using icariin-loaded ß-cyclodextrin sulfate had a greater patency rate. Scanning electron microscopy (SEM) and CD31 immunofluorescence results showed a better degree of endothelialization. Taken together, icariin-loaded ß-cyclodextrin sulfate can achieve anticoagulation and rapid endothelialization of TEBVs to ensure their long-term patency.

Development of a simple IgE-independent anaphylactic model using buckwheat antigen and B-type CpG oligodeoxynucleotide from Streptococcus thermophilus.

We developed a severe anaphylactic model in mice using buckwheat antigen and B-type CpG-oligodeoxynucleotides (CpG-ODNs) from Streptococcus thermophilus genome. In typical systemic anaphylaxis models, animals are challenged with large quantity of antigens via an intravenous (i.v.) route. Here, we showed a simple anaphylactic shock after challenge via intraperitoneal (i.p.) route. The i.p. method is simpler than i.v. administration and has a lower risk for failure. To generate this anaphylactic model, 5-week-old female BALB/c mice were first i.p. sensitized with buckwheat antigen mixed with B-type CpG-ODN. After 2 weeks, mice were challenged with antigen to induce anaphylactic shock, which was evaluated by scoring the severity symptoms and measuring serum levels of various proteins and splenic cell producing cytokines. Immunoglobulin (Ig)G2a production and interferon-γ positive cells were markedly increased in mice immunized with antigen mixed with B-type CpG-ODN, whereas serum IgE levels were decreased by B-type CpG-ODN. We also examined the effects of various ODNs (A, B and C-type CpG-ODNs) and antigens (buckwheat, α-casein, ß-lactoglobulin and ovalbumin) on anaphylactic severity, and found that the combination of buckwheat and B-type CpG-ODN induced the most intense anaphylactic shock. This model is expected to contribute to the study of the prevention of anaphylactic shock.