Butyrate Enhances Disease Resistance of Chickens by Inducing Antimicrobial Host Defense Peptide Gene Expression

Host defense peptides (HDPs) constitute a large group of natural broad-spectrum antimicrobials and an important first line of immunity in virtually all forms of life. Specific augmentation of synthesis of endogenous HDPs may represent a promising antibiotic-alternative approach to disease control. In this study, we tested the hypothesis that exogenous administration of butyrate, a major type of short-chain fatty acids derived from bacterial fermentation of undigested dietary fiber, is capable of inducing HDPs and enhancing disease resistance in chickens. We have found that butyrate is a potent inducer of several, but not all, chicken HDPs in HD11 macrophages as well as in primary monocytes, bone marrow cells, and jejuna and cecal explants. In addition, butyrate treatment enhanced the antibacterial activity of chicken monocytes against Salmonella enteritidis, with a minimum impact on inflammatory cytokine production, phagocytosis, and oxidative burst capacities of the cells. Furthermore, feed supplementation with 0.1% butyrate led to a significant increase in HDP gene expression in the intestinal tract of chickens. More importantly, such a feeding strategy resulted in a nearly 10-fold reduction in the bacterial titer in the cecum following experimental infections with S. enteritidis. Collectively, the results indicated that butyrate-induced synthesis of endogenous HDPs is a phylogenetically conserved mechanism of innate host defense shared by mammals and aves, and that dietary supplementation of butyrate has potential for further development as a convenient antibiotic-alternative strategy to enhance host innate immunity and disease resistance

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

A three-dimensional vision measurement method based on double-line combined structured light

Abstract In this paper, a structured light vision measurement method using a scanning laser line and a positioning laser line is proposed. The novel method enables the scanning laser plane to slide along a slide rail while maintaining intersection with the positioning laser plane, eliminating the need to determine the scanning direction and moving step. During the measurement process, the laser plane equations need to be recalibrated for each new position, so a real-time calibration method is given. Initially, the geometric barycenter method is employed to detect the subpixel coordinates of the light stripe intersection point. Subsequently, these coordinates are projected into the camera coordinate system using the initial equations of the positioning laser plane. Finally, leveraging the normal information of the initial equation of the scanning laser plane and the three-dimensional coordinates of the light stripe intersection point, the real-time calibration of the scanning laser plane equations can be accomplished. The proposed method enables the three-dimensional reconstruction of objects, and its accuracy is verified through measurements on gauge blocks. Experimental results demonstrate that this method achieves precise and stable three-dimensional reconstruction of object surface shape

A Three-Dimensional Structured Light Vision System by Using a Combination of Single-Line and Three-Line Lasers

A multi-line structured light measurement method that combines a single-line and a three-line laser, in which precision sliding rails and displacement measurement equipment are not required, is proposed in this paper. During the measurement, the single-line structured light projects onto the surface of an object and the three-line structured light remains fixed. The single-line laser is moved and intersects with the three-line laser to form three intersection points. The single-line light plane can be solved using the camera coordinates of three intersection points, thus completing the real-time calibration of the scanned light plane. The single-line laser can be scanned at any angle to determine the overall complete three-dimensional (3D) shape of the object during the process. Experimental results show that this method overcomes the difficulty of obtaining information about certain angles and locations and can effectively recover the 3D shape of the object. The measurement system’s repetition error is under 0.16 mm, which is sufficient to measure the 3D shapes of complicated workpieces

Butyrate Enhances Disease Resistance of Chickens by Inducing Antimicrobial Host Defense Peptide Gene Expression

Host defense peptides (HDPs) constitute a large group of natural broad-spectrum antimicrobials and an important first line of immunity in virtually all forms of life. Specific augmentation of synthesis of endogenous HDPs may represent a promising antibiotic-alternative approach to disease control. In this study, we tested the hypothesis that exogenous administration of butyrate, a major type of short-chain fatty acids derived from bacterial fermentation of undigested dietary fiber, is capable of inducing HDPs and enhancing disease resistance in chickens. We have found that butyrate is a potent inducer of several, but not all, chicken HDPs in HD11 macrophages as well as in primary monocytes, bone marrow cells, and jejuna and cecal explants. In addition, butyrate treatment enhanced the antibacterial activity of chicken monocytes against Salmonella enteritidis, with a minimum impact on inflammatory cytokine production, phagocytosis, and oxidative burst capacities of the cells. Furthermore, feed supplementation with 0.1% butyrate led to a significant increase in HDP gene expression in the intestinal tract of chickens. More importantly, such a feeding strategy resulted in a nearly 10-fold reduction in the bacterial titer in the cecum following experimental infections with S. enteritidis. Collectively, the results indicated that butyrate-induced synthesis of endogenous HDPs is a phylogenetically conserved mechanism of innate host defense shared by mammals and aves, and that dietary supplementation of butyrate has potential for further development as a convenient antibiotic-alternative strategy to enhance host innate immunity and disease resistance.This article is from PLoS One 6 (2011): e27225, doi:10.1371/journal.pone.0027225.</p

Deep Understanding of Strong Metal Interface Confinement: A Journey of Pd/FeOx Catalysts

Tuning the atomic interface configuration of noble metals (NMs) and transition-metal oxides is an effective straightforward yet challenging strategy to modulate the activity and stability of heterogeneous catalysts. Herein, Pd supported on mesoporous Fe2O3 with a high specific surface area was rationally designed and chosen to construct the Pd/iron oxide interface. As a versatile model, the physicochemical environments of Pd nanoparticles (NPs) could be precisely controlled by taming the reduction temperature. The experimental and density functional theory calculation results unveiled that the catalyst in the support-metal interface confinement (SMIC) state showed significantly enhanced catalytic activity and sintering resistance for CO oxidation. The constructed Fe sites at the interfaces between FeOx overlayers and Pd NPs not only provided additional coordinative unsaturated ferrous sites for the adsorption and activation of O-2, thereby facilitating the activation efficiency of O-2, but also impressively changed the reaction pathway of CO oxidation. As a result, the catalyst followed the Pd/Fe dual-site mechanism instead of the classical Mars-van Krevelen mechanism. For the catalyst in the strong metal-support interaction (SMSI) state, its catalytic activity was seriously suppressed because of the excessive encapsulation of the active Pd sites by FeOx overlayers. The present study therefore provides detailed insights into the SMIC and SMSI in ferric oxide-supported Pd catalysts, which could guide the preparation of highly efficient supported catalysts for practical applications

Gold Microbeads Enabled Proximity Electrochemiluminescence for Highly Sensitive and Size-Encoded Multiplex Immunoassays

Developing highly sensitive multiplex immunoassays is urgently needed to guide medical research and improve clinical diagnosis. Here, we report the proximity electrochemiluminescence (ECL) generation enabled by gold microbeads (GMBs) for improving the detection sensitivity and multiplexing capacity of ECL immunoassays (ECLIAs). As demonstrated by microscopy and finite element simulation, GMBs can function as spherical ultramicroelectrodes for triggering ECL reactions in solutions. Employing GMBs as solid carriers in the bead-based ECLIA, the electrochemical oxidation of a coreactant can occur at both the GMB surface and the substrate electrode, allowing the coreactant radicals to diffuse only a short distance of ∼100 nm to react with ECL luminophores that are labeled on the GMB surface. The ECL generation via this proximity low oxidation potential (LOP) route results in a 21.7-fold increase in the turnover frequency of ECL generation compared with the non-conductive microbeads that rely exclusively on the conventional LOP route. Moreover, the proximity ECL generation is not restricted by the diffusion distance of short-lived coreactant radicals, which enables the simultaneous determination of multiple acute myocardial infarction biomarkers using size-encoded GMB-based multiplex ECLIAs. This work brings new insight into the understanding of ECL mechanisms and may advance the practical use of multiplex ECLIAs

Anionic Polymerization of Oxadiazole-Containing 2‑Vinylpyridine by Precisely Tuning Nucleophilicity and the Polyelectrolyte Characteristics of the Resulting Polymers

Anionic polymerization is one of the most powerful techniques for preparation of well-defined polymers. However, this well-known and widely employed polymerization technique encounters major limitations for the polymerization of functional monomers containing heteroatoms. This work presents the anionic polymerization of 2-phenyl-5-(6-vinylpyridin-3-yl)-1,3,4-oxadiazole (VPyOzP), a heteroatom monomer that contains both oxadiazole and pyridine substituents within the same pendant group, using various initiating systems based on diphenyl­methyl potassium (DPM-K) and triphenyl­methyl potassium (TPM-K). Remarkably, well-defined poly­(2-phenyl-5-(6-vinylpyridin-3-yl)-1,3,4-oxadiazole) (PVPyOzP) polymers having predicted molecular weights (MW) ranging from 2200 to 21 100 g/mol and polydispersity indices (PDI) ranging from 1.11 to 1.15 were prepared with TPM-K, without any additional additives, at −78 °C. The effect of temperature on the polymerization of PVPyOzP was also studied at −78, −45, 0, and 25 °C, and it was observed that increasing the polymerization temperature produced materials with unpredictable MW’s and broader molecular weight distributions. Furthermore, the nucleophilicity of PVPyOzP was investigated through copolymerization with methyl methacrylate and acrylonitrile, where only living poly­(methyl methacrylate) (PMMA) prepared by DPM-K/VPPy and in the absence of additives such as lithium chloride (LiCl) and diethyl zinc (ZnEt₂) could be used to produce the well-defined block copolymer of PMMA-<i>b</i>-PVPyOzP. It was also demonstrated by sequential monomer addition that the nucleophilicity of living PVPyOzP is located between that of living PMMA and polyacrylonitrile (PAN). The pyridine moiety of the pendant group also allowed for quaternization and produced PQVPyOzP homopolymer using methyl iodide (CH₃I) and bis­(trifluoro­methyl­sulfonyl)­amide [Tf₂N^–]. The resulting charged polymer and counterion complexes were manipulated and investigated for potential use as membranes for carbon dioxide (CO₂) capture

Additional file 1 of Risks of digestive diseases in long COVID: evidence from a population-based cohort study

Additional file 1: Figure S1. Directed Acyclic Graphs (DAG) for covariate selection. Figure S2. Flow chart of eligible participants’ selection. Figure S3. Distribution of follow-up time in the contemporary cohort (A) and the historical cohort (B). Figure S4. Hazard ratio of digestive outcomes in COVID-19 group and the contemporary comparison by severity of COVID-19. Table S1. Respiratory support treatments definition. Table S2. Outcome ascertainment. Table S3. The numbers (percentages) of participants with missing covariates. Table S4. Baseline characteristics of COVID-19 group and contemporary comparisons before weighting. Table S5. Hazard ratio of digestive outcomes in COVID-19 group and the contemporary comparison at different follow-up times. Table S6. Baseline characteristics of COVID-19, contemporary comparisons by severity of COVID-19 before weighting. Table S7. Baseline characteristics of COVID-19, contemporary comparisons by severity of COVID-19 after weighting. Table S8. Baseline characteristics of COVID-19 group and contemporary comparisons by status of SARS-CoV reinfection before weighting. Table S9. Baseline characteristics of COVID-19 group and contemporary comparisons by severity of SARS-CoV reinfection after weighting. Table S10. Hazard ratio of digestive outcomes in the reinfected group, single SARS-CoV-2 infection group, and non-infected comparisons. Table S11. Hazard ratio of digestive outcomes in reinfected group and single SARS-CoV-2 infection group in head-to-head comparison. Table S12. Baseline characteristics of COVID-19 group and contemporary comparisons in the sensitive analysis restricting to the period before vaccination was available before weighting. Table S13. Baseline characteristics of COVID-19 group and contemporary comparisons in the sensitive analysis restricting to the period before vaccination was available after weighting. Table S14. Hazard ratio of digestive outcomes in COVID-19 group and contemporary and historical comparisons in subgroups in the sensitive analysis restricting to the period before vaccination was available. Table S15. Hazard ratio of digestive outcomes in COVID-19 group compared to the contemporary and historical comparisons by pooling estimates across all five imputed datasets. Table S16. Hazard ratio of digestive outcomes compared with contemporary and historical comparisons in subgroups. Table S17. Hazard ratio of digestive outcomes in COVID-19 group, the contemporary and historical comparison by sex. Table S18. Baseline characteristics of COVID-19 group and historical comparisons before weighting. Table S19. Baseline characteristics of COVID-19 group and historical comparisons after weighting. Table S20. Baseline characteristics of COVID-19 group and historical comparisons by severity of COVID-19 before weighting. Table S21. Baseline characteristics of COVID-19 group and historical comparisons by severity of COVID-19 after weighting. Table S22. Baseline characteristics of COVID-19 group and historical comparisons in the sensitive analysis restricting to the period before vaccination was available before weighting. Table S23. Baseline characteristics of COVID-19 group and historical comparisons in the sensitive analysis restricting to the period before vaccination was available after weighting. Table S24. Hazard ratio of digestive outcomes in COVID-19 group and the historical comparison by severity of COVID-19