Direct-ink-write cross-linkable bottlebrush block copolymers for on-the-fly control of structural color.

Additive manufacturing capable of controlling and dynamically modulating structures down to the nanoscopic scale remains challenging. By marrying additive manufacturing with self-assembly, we develop a UV (ultra-violet)-assisted direct ink write approach for on-the-fly modulation of structural color by programming the assembly kinetics through photo-cross-linking. We design a photo-cross-linkable bottlebrush block copolymer solution as a printing ink that exhibits vibrant structural color (i.e., photonic properties) due to the nanoscopic lamellar structures formed post extrusion. By dynamically modulating UV-light irradiance during printing, we can program the color of the printed material to access a broad spectrum of visible light with a single ink while also creating color gradients not previously possible. We unveil the mechanism of this approach using a combination of coarse-grained simulations, rheological measurements, and structural characterizations. Central to the assembly mechanism is the matching of the cross-linking timescale with the assembly timescale, which leads to kinetic trapping of the assembly process that evolves structural color from blue to red driven by solvent evaporation. This strategy of integrating cross-linking chemistry and out-of-equilibrium processing opens an avenue for spatiotemporal control of self-assembled nanostructures during additive manufacturing.

Mannose metabolism normalizes gut homeostasis by blocking the TNF-α-mediated proinflammatory circuit.

Mannose is a naturally occurring sugar widely consumed in the daily diet; however, mechanistic insights into how mannose metabolism affects intestinal inflammation remain lacking. Herein, we reported that mannose supplementation ameliorated colitis development and promoted colitis recovery. Macrophage-secreted inflammatory cytokines, particularly TNF-α, induced pathological endoplasmic reticulum stress (ERS) in intestinal epithelial cells (IECs), which was prevented by mannose via normalization of protein N-glycosylation. By preserving epithelial integrity, mannose reduced the inflammatory activation of colonic macrophages. On the other hand, mannose directly suppressed macrophage TNF-α production translationally by reducing the glyceraldehyde 3-phosphate level, thus promoting GAPDH binding to TNF-α mRNA. Additionally, we found dysregulated mannose metabolism in the colonic mucosa of patients with inflammatory bowel disease. Finally, we revealed that activating PMM2 activity with epalrestat, a clinically approved drug for the treatment of diabetic neuropathy, elicited further sensitization to the therapeutic effect of mannose. Therefore, mannose metabolism prevents TNF-α-mediated pathogenic crosstalk between IECs and intestinal macrophages, thereby normalizing aberrant immunometabolism in the gut.

Effects of Bu Shen Hua Zhuo formula on the LPS/TLR4 pathway and gut microbiota in rats with letrozole-induced polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in gynecology. Traditional Chinese medicine (TCM) is widely used for the treatment of PCOS in China. The Bu Shen Hua Zhuo formula (BSHZF), a TCM decoction, has shown great therapeutic efficacy in clinical practice. However, the mechanism underlying the BSHZF function in PCOS remains unclear. This study aimed to identify the potential mechanisms of action of BSHZF in the treatment of PCOS. PCOS-model rats treated with letrozole were administered different doses of BSHZF, metformin, and 1% carboxymethylcellulose. Serum sex hormones, fasting blood glucose, and fasting insulin levels were measured, and the morphology of the ovaries was observed in each group, including the normal group. The structure and abundance of the gut microbiota in rats were measured using 16S ribosomal RNA gene sequencing. Toll-like receptor 4 (TLR4) and phospho-NF-κB p65 levels in the ovarian tissue of the rats were detected using Western blotting. Furthermore, the levels of lipopolysaccharide (LPS) and inflammatory cytokines TNF-α, IL-6, and IL-8 in the serum of rats were detected by ELISA. The results showed that BSHZF administration was associated with a decrease in body weight, fasting blood glucose, fasting insulin, and testosterone and changes in ovarian morphology in PCOS-model rats. Moreover, BSHZF was associated with an increase in the α-diversity of gut microbiota, decrease in the relative abundance of Firmicutes, and increase in Lactobacillus and short chain fatty acid-producing bacteria (Allobaculum, Bacteroides, Ruminococcaceae_UCG-014). Furthermore, BSHZF may promote carbohydrate and protein metabolism. In addition, BSHZF was associated with a decrease in the serum level of LPS and TLR4 expression, thereby inhibiting the activation of the NF-κB signaling-mediated inflammatory response in ovarian tissue. Therefore, the beneficial effects of BSHZF on PCOS pathogenesis are associated with its ability to normalize gut microbiota function and inhibit PCOS-related inflammation.

Concentration-Driven Self-Assembly of PS-b-PLA Bottlebrush Diblock Copolymers in Solution.

Bottlebrush polymers are a class of semiflexible, hierarchical macromolecules with unique potential for shape-, architecture-, and composition-based structure-property design. It is now well-established that in dilute to semidilute solution, bottlebrush homopolymers adopt a wormlike conformation, which decreases in extension (persistence length) as the concentration and molecular overlap increase. By comparison, the solution phase self-assembly of bottlebrush diblock copolymers (BBCP) in a good solvent remains poorly understood, despite critical relevance for solution processing of ordered phases and photonic crystals. In this work, we combine small-angle X-ray scattering, coarse-grained simulation, and polymer synthesis to map the equilibrium phase behavior and conformation of a set of large, nearly symmetric PS-b-PLA bottlebrush diblock copolymers in toluene. Three BBCP are synthesized, with side chains of number-averaged molecular weights of 4500 (PS) and 4200 g/mol (PLA) and total backbone degrees of polymerization of 100, 255, and 400 repeat units. The grafting density is one side chain per backbone repeat unit. With increasing concentration in solution, all three polymers progress through a similar structural transition: from dispersed, wormlike chains with concentration-dependent (decreasing) extension, through the onset of disordered PS/PLA compositional fluctuations, to the formation of a long-range ordered lamellar phase. With increasing concentration in the microphase-separated regimes, the domain spacing increases as individual chains partially re-extend due to block immiscibility. Increases in the backbone degree of polymerization lead to changes in the scattering profiles which are consistent with the increased segregation strength. Coarse-grained simulations using an implicit side-chain model are performed, and concentration-dependent self-assembly behavior is qualitatively matched to experiments. Finally, using the polymer with the largest backbone length, we demonstrate that lamellar phases develop a well-defined photonic band gap in solution, which can be tuned across the visible spectrum by varying polymer concentration.

Development and evaluation of an inactivated coxsackievirus A16 vaccine in gerbils.

Coxsackievirus A16 (CVA16) is one of the major pathogens responsible for human hand, foot, and mouth disease (HFMD), which has threatened the health of young children, particularly in Asia-Pacific nations. Vaccination is an effective strategy for protecting children from CVA16 infection. However, there is currently no licensed CVA16 vaccine for use in humans. In this study, we isolated a high-growth CVA16 virus strain in MRC-5 cells and developed an MRC-5-adapted vaccine candidate strain termed CVA16-393 via two rounds of plaque purification. The CVA16-393 strain was grouped into the B1b subgenotype and grew to a titre of over 107 TCID50/ml in MRC-5 cells. The VP1 gene region of this strain, which contains the major neutralizing epitopes, displayed high stability during serial passages. The inactivated whole-virus vaccine produced by the CVA16-393 strain induced an effective neutralizing antibody response in Meriones unguiculatus (gerbils) after two doses of intraperitoneal inoculation. One week after the booster immunization, the geometric mean titres of the neutralizing antibodies for the 10246, 40812TXT, 11203SD, TJ-224 and CA16-194 strains from different regions of China were 137.8, 97.8, 113.4, 64.1 and 122.3, respectively. A CVA16 vaccine dose above 25 U was also able to provide 100% cross-protection against lethal challenges with these five clinical strains in gerbils. Immunization at a one-week interval could maintain a high level of neutralizing antibody titres for at least 8 weeks. Thus, the vaccine produced by this CVA16-393 strain might be promising.

A fluorescent microsphere-based immunochromatographic strip is effective for quantitative fecal blood testing in colorectal cancer screening.

Background: Colorectal cancer (CRC) represents a major health concern that can be screened for by the fecal immunochemical test (FIT), which detects blood in the stool. CRC detection sensitivity for hemoglobin (Hb) combined with transferrin (Tf) is higher than for hemoglobin alone. Methods: We developed a europium fluorescent microsphere-based quantitative lateral flow immunochromatography strip to detect fecal Hb and Tf. Performance was tested using fecal samples from 51 patients with CRC and 122 normal subjects. Test strips were generated using paired mouse anti-human Hb and mouse anti-human Tf monoclonal antibodies and tested using standard Hb and Tf samples. Fluorescence was observed at 365 nm and quantitatively measured using a portable fluorescent strip reader. Results: At cutoff values of 100 ng/mL (10 µg/g feces) and 25 ng/mL (2.5 µg/g feces) for Hb and Tf, respectively, the positive rates for Hb, Tf, and Hb+Tf in normal subjects were 6.56%, 5.74%, and 10.66%, respectively, compared to 88.24%, 64.71%, and 94.12% in patients with CRC. The sensitivity and specificity of the FIT combined detection technique were 87.5% and 89.2%, respectively, and the area under the curve (AUC) was 0.92. The sensitivity, specificity, and AUC for the Tf assay were 63.8%, 68.4%, and 0.759, respectively, and those for Hb testing were 69.7%, 70.2%, and 0.774, respectively. The AUC for Hb+Tf was significantly higher than those for Tf or Hb alone (P < 0.001). Conclusions: Fluorescent microsphere-based immunochromatographic strips sensitively detect fecal Hb and Tf, and sensitivity and specificity are improved for Hb+Tf. This system represents a rapid and portable alternative for on-site early CRC screening.

Interaction potential for coarse-grained models of bottlebrush polymers.

Bottlebrush polymers are a class of highly branched macromolecules that show promise for applications such as self-assembled photonic materials and tunable elastomers. However, computational studies of bottlebrush polymer solutions and melts remain challenging due to the high computational cost involved in explicitly accounting for the presence of side chains. Here, we consider a coarse-grained molecular model of bottlebrush polymers where the side chains are modeled implicitly, with the aim of expediting simulations by accessing longer length and time scales. The key ingredients of this model are the size of a coarse-grained segment and a suitably coarse-grained interaction potential between the non-bonded segments. Prior studies have not focused on developing explicit forms of such potentials, instead, relying on scaling arguments to model non-bonded interactions. Here, we show how to systematically calculate an interaction potential between the coarse-grained segments of bottlebrush from finer grained explicit side chain models using Monte Carlo and Brownian dynamics and then incorporate it into an implicit side chain model. We compare the predictions from our coarse-grained implicit side chain model with those obtained from models with explicit side chains in terms of the potential of mean force, the osmotic second virial coefficient, and the interpenetration function, highlighting the range of applicability and limitations of the coarse-grained representation. Although presented in the context of homopolymer bottlebrushes in athermal solvents, our proposed method can be extended to other solvent conditions as well as to different monomer chemistries. We expect that our implicit side chain model will prove useful for accelerating large-scale simulations of bottlebrush solutions and assembly.

Functional analysis of a novel repressor LuxR in Comamonas testosteroni.

Comamonas testosteroni (C. testosteroni) ATCC11996 is a gram negative bacterium which can use steroid as a carbon and energy source. 3,17ß-hydroxysteroid dehydrogenase (3,17ß-HSD) is a key enzyme for the degradation of steroid hormones in C. testosteroni. The LuxR regulation family is a group of regulatory proteins which play important role in gram negative bacterium. The luxr gene is located on 58 kb upstream of 3,17ß-HSD gene with the opposite transcription orientation in the chromosomal DNA of C. testosteroni. An open reading frame of this putative luxr gene consists of 1125 bp and is translated into a protein containing 374 amino acids. The luxr gene was cloned into plasmid pK18 and plasmid pK-LuxR1 was obtained. E. coli HB101 was co-transformed by pK-LuxR1 and pUC912-10, pUC1128-5 or pUC3.2-4 (which contain ßhsd gene and different length promoter, repeat sequences). The result of ELISA showed that LuxR protein is a negative regulator for 3,17ß-HSD expression. The luxr gene in C. testosteroni was knock-out by homologous integration. 3,17ß-HSD expression was increased in the mutant (C.T.-L-KO1) comparing to that in wild-type C. testosteroni (C.T.) after 0.5 mM testosterone induction. The mutant C.T.-L-KO1 and wild-type C. testosteroni were cultured at 27 °C and 37 °C. The result of growth curve proved that LuxR has also effect on the bacterial growth.

Isolation and identification of a repressor TetR for 3,17ß-HSD expressional regulation in Comamonas testosteroni.

Comamonas testosteroni (C. testosteroni) is able to catabolize a variety of steroids and polycyclic aromatic hydrocarbons. 3,17ß-Hydroxysteroid dehydrogenase (3,17ß-HSD) from C. testosteroni is a key enzyme in steroid degradation. Understanding the mechanism of 3,17ß-HSD gene (ßhsd) induction may help us to elucidate its complete molecular regulation. Sequencing the C. testosteroni ATCC11996 genome lead us to identify the tetR (522 bp) downstream of ßhsd. Two repeat sequences (RS; 13 bp), that are separated to each other by 1661 bp, were found upstream of ßhsd. A bioinformatic analysis revealed that TetR family proteins act as transcriptional repressors which are sensitive to environmental signals. Since, C. testosteroni responds to environmental steroid induction and upregulates steroid catabolic genes, we hypothesized that TetR might act in C. testosteroni as repressor for ßhsd expression. The tetR was cloned into different plasmids, including an EGFP reporter system, for functional characterization and/or overexpression. The data indicate that, indeed, TetR acts as a repressor for 3,17ß-HSD expression. Testosterone in turn, which is known to induce ßhsd expression, could not resolve TetR repression. To further substantiate TetR as repressor for ßhsd expression, a tetR gene knock-out mutant of C. testosteroni was generated. TetR gene knock-out mutants showed the same basal low level of ßhsd expression as the C. testosteroni wild type cells. Interestingly, testosterone induction leads to a strong increase in ßhsd expression, especially in the tetR gene knock-out mutants. The result with the knock-out mutant, in principle, supports our hypothesis that TetR is a repressor for ßhsd expression, but the exact role of testosterone in this context remains unknown. Finally, it turned out that TetR is obviously also involved in the regulation of the hsdA gene.