T follicular regulatory (Tfr) cell is a recently discovered subset of T regulatory (Treg) cells. The main function of Tfr cells is thought to suppress germinal cancer reaction and inhibit B cell proliferation and Ig production. However, recent studies demonstrate that Tfr cells may be required for high-affinity Ig formation during acute virus infections. The role of Tfr cells in breast cancer is not thoroughly investigated. In this study, total circulating CD4 T cells were sorted into CD25+CXCR5− Treg-like, CD25+CXCR5+ Tfr-like, and CD25−CXCR5+ Tfh-like subsets. Data showed that the Tfr-like subset presented intermediate levels of both Foxp3 and Bcl-6, while the Treg-like subset was high in Foxp3 and low in Bcl-6, and the Tfh-like was high in Bcl-6 and low in Foxp3. Of note, the frequencies of Tfr-like and Treg-like cells were significantly elevated in breast cancer (BC) patients than in non-cancer (NC) controls. Tfr-like cells in BC patients also expressed significantly higher levels of Foxp3 than those in NC controls. Neither Treg-like nor Tfr-like cells could support Ig production from naive B cells, while Tfh-like cells potently supported Ig production from naive B cells. Tfr-like cells increased the availability of IL-10, both by directly producing IL-10 and by increasing IL-10 production from B cells. Interestingly, Tfr-like cells increased IL-10 production from B cells synergistically with Tfh cells, but at the same time, significantly reduced Ig production in the Tfh-B cell coculture. These Tfr-mediated effects on Tfh cells were not found in canonical Treg cells. Overall, this study demonstrates several distinctive features in circulating Tfr cells and suggests that Tfr cells may promote the formation of IL-10-producing B cells in BC.
Some species of mycobacteria have been modified to transform sterols to valuable steroid synthons. The unique cell wall of mycobacteria has been recognized as an important organelle to absorb sterols. Some cell wall inhibitors (e.g., vancomycin and glycine) have been validated to enhance sterol conversion by interfering with transpeptidation in peptidoglycan biosynthesis. Therefore, two transpeptidase genes, pbpA and pbpB, were selected to rationally modify the cell wall to simulate the enhancement effect of vancomycin and glycine on sterol conversion in a 22‐hydroxy‐23,24‐bisnorchol‐4‐ene‐3‐one (4‐HBC) producing strain (WIII). Unexpectedly, the pbpA or pbpB gene augmentation was conducive to the utilization of sterols. The pbpB augmentation strain WIII‐pbpB was further investigated for its better performance. Compared to WIII, the morphology of WIII‐pbpB was markedly changed from oval to spindle, indicating alterations of the cell wall. Biochemical analysis indicated that the altered cell wall properties of WIII‐pbpB might contribute to the positive effect on sterol utilization. The productivity of 4‐HBC was enhanced by 28% in the WIII‐pbpB strain compared to that of WIII. These results demonstrated that the modification of peptidoglycan synthesis can improve the conversion of sterols to steroid synthons in mycobacteria. 相似文献
Parasitology Research - In our previous study, we obtained a large number of differentially expressed genes (DEGs) between second-generation merozoites (MZ-2) and third-generation merozoites (MZ-3)... 相似文献
Virus Genes - As an opportunist pathogen, Vibrio alginolyticus (V. alginolyticus), causes disease in marine animals. Bacterial contamination of seafood is not uncommon, and phage therapy is... 相似文献
Cellulose is a kind of natural polymer material, which is composed of bundle-like fibrils. By peeling the fibrils layer by layer, the size of cellulose can be nanocrystallized, and nanofibers and nanocrystals with unique and potentially useful features can be prepared. As an emerging functional polymer material, nanocellulose has become a research hotspot in the field of technology. This review discusses the preparation of nanocellulose, including the commonly used hydrolysis, oxidation, physical and environmentally friendly ionic liquid methods. The advantages and disadvantages of different methods are also compared. And the review introduced the application of nanofiberized cellulose and nanocellulose crystals in the fields of thermosetting and thermoplastics, such as polylactic acid, polypropylene, epoxy resin and so on. The critical factors in the manufacturing of nanocellulose composites and mechanical properties are discussed to provide a reference for the further application and development of nanocellulose. 相似文献
Supramolecular polymer vesicles (SPVs) with stimuli‐responsive features are promising multifunctional nanocarriers; however, improving the stability and developing multiple‐drug‐loaded SPVs remain key issues in this field. In this work, cross‐linked supramolecular hyperbranched polymer vesicles (SHPVs) with redox‐responsiveness are first constructed based on an AB2‐type macromonomer‐synthesized SHP. The obtained cross‐linked SHPVs exhibit much better size stability than those of non‐cross‐linked branched self‐assemblies, and higher double‐drug‐loading capacity compared with linear supramolecular polymer self‐assemblies. Particularly, these cross‐linked SHPVs exhibit a redox‐triggered, controlled double‐drug release behavior upon the addition of H2O2. 相似文献
Injectable self‐healing hydrogels have drawn growing attention for their extensive applications in biomedical fields. Hydrogels containing nanoparticles also exhibit promising potentials in catalysis, wastewater treatment, and organic synthesis. Inspired by the multifunction of gallol presented herein, a simple one‐pot method to produce a gallol‐tethered gelatin hydrogel via Schiff base under oxidizing conditions using various oxidants is presented. The hydrogels prepared by NaIO4‐induced cross‐linking present a high self‐healing rate (up to 84.5%), injectable ability, tunable mechanical property, flexible viscoelasticity, and macroporous structure owing to the combination of covalent cross‐linking and supramolecular interactions. HAuCl4 contributes to the 3D structure formation of the gelatin hydrogel via oxidation cross‐linking. It is reduced by the gallol groups to produce nanogold (AuNP)‐decorated hydrogel (Au‐gel). This Au‐gel is fully characterized by UV–vis, XRD, TEM, SEM, EDX, and ICP‐MS and exhibits a high‐catalytic activity for the reduction of 4‐nitrophenol. The solid Au‐gel catalyst is robust, easily recyclable, and reused at least eight times. 相似文献
Efficient production of high‐quality, functionalized graphene is highly desirable for large‐scale applications of graphene. Herein, a route for producing high‐quality, polystyrene (PS)‐functionalized graphene is demonstrated via graphite exfoliation in chloroform with a heterobifunctional hyperbranched polyethylene, HBPE@Py@PS, as stabilizer. The HBPE@Py@PS, possessing a pyrene‐functionalized hyperbranched polyethylene backbone and multiple PS side chains, is synthesized by combining chain walking polymerization and atom transfer radical polymerization techniques. It is confirmed that the HBPE@Py@PS can effectively promote graphite exfoliation in chloroform under sonication to render stable dispersions of high‐quality graphene, with an exfoliation efficiency high as 15% and a monolayer proportion, 61%. Meanwhile, it can irreversibly adsorb on the exfoliated graphene surface based on the π–π stacking interactions, concurrently rendering PS‐functionalized graphene that is fluorescent and highly dispersible in chloroform, with a film conductivity reaching 1100 S m?1. The as‐produced graphene may find its applications as nanofiller for various PS‐based graphene nanocomposites. 相似文献
In the last several years, multiple‐shape memory liquid crystalline networks (LCNs) have received more and more attention due to the basic theoretical research on them and their wide potential applications. In this article, a novel main‐chain/side‐chain liquid crystalline monomer and its corresponding polymer networks based on the thiol‐ene click reaction are reported. Properties of the synthesized liquid crystalline monomer are well studied with nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) spectra, differential scanning calorimetry (DSC), and polarized optical microscopy (POM). The as‐prepared free‐standing LCN films are investigated well by FTIR, DSC, POM, and X‐ray diffraction (XRD), which show them having good liquid crystalline properties. Tensile test and dynamical mechanical analysis (DMA) results indicate the LCN films have excellent thermal mechanical properties. By adjusting the crosslinking densities, LCN films exhibit two thermal transition temperatures (Tg and TNI) that can be utilized to trigger the triple‐shape memory behaviors. The cyclic thermal mechanical analysis conducted by DMA reveals that LCN films exhibit good triple‐shape memory properties with high‐shape fixity ratio (Rf (S1→S2) is 99.2% and Rf (S2→S3) is 99.3%) and shape recovery ratio (Rr (S3→S2) is 92.4% and Rr (S2→S1) is 98.5%). 相似文献