Pectin limits epithelial barrier disruption by Citrobacter rodentium through anti-microbial effects

SCOPE: C. rodentium is the murine equivalent of Enteropathogenic Escherichia. coli (EPEC) and Enterohemorrhagic Escherichia coli (EHEC) which induce damage to the intestinal epithelial barrier that results in diarrhea and intestinal inflammation. Dietary fibre intake can be an effective approach to limit epithelial damage by these enteric pathogens. Therefore, the protective effect of dietary fibre pectin against dysfunction of epithelial barrier integrity upon C. rodentium infection was investigated. METHODS AND RESULTS: Pectins that structurally differed in the degree and distribution of methylesters were tested on barrier protective effects on epithelial cells against C. rodentium by measuring transepithelial electrical resistance and lucifer yellow fluxes. All three pectins protected the epithelial barrier from C. rodentium induced damage in a structure-independent manner. These barrier protective effects were also independent of pectin-induced TLR2 activation. Furthermore, the pectins induced anti-adhesive effects on C. rodentium by interacting with C. rodentium and not with epithelial cells. This may be explained by antimicrobial effects of pectins on C. rodentium and not on other enteric bacteria including Lactobacillus plantarum and E. coli. A competition ELISA for binding of C. rodentium to pectin supported this finding as it showed that pectin interacts strongly with C. rodentium, whereas it interacts weakly or not with L. plantarum or E. coli. CONCLUSION: These findings demonstrate that pectin protects the epithelial barrier from C. rodentium induced damage by inducing anti-microbial effects

Attenuation of Doxorubicin-Induced Small Intestinal Mucositis by Pectins is Dependent on Pectin's Methyl-Ester Number and Distribution

Scope Intestinal mucositis is a common side effect of the chemotherapeutic agent doxorubicin, which is characterized by severe Toll-like receptor (TLR) 2-mediated inflammation. The dietary fiber pectin is shown to prevent this intestinal inflammation through direct inhibition of TLR2 in a microbiota-independent manner. Recent in vitro studies show that inhibition of TLR2 is determined by the number and distribution of methyl-esters of pectins. Therefore, it is hypothesized that the degree of methyl-esterification (DM) and the degree of blockiness (DB) of pectins determine attenuating efficacy on doxorubicin-induced intestinal mucositis. Methods and Results Four structurally different pectins that differed in DM and DB are tested on inhibitory effects on murine TLR2 in vitro, and on doxorubicin-induced intestinal mucositis in mice. These data demonstrate that low DM pectins or intermediate DM pectins with high DB have the strongest inhibitory impact on murine TLR2-1 and the strongest attenuating effect on TLR2-induced apoptosis and peritonitis. Intermediate DM pectin with a low DB is, however, also effective in preventing the induction of doxorubicin-induced intestinal damage. Conclusion These pectin structures with stronger TLR2-inhibiting properties may prevent the development of doxorubicin-induced intestinal damage in patients undergoing chemotherapeutic treatment with doxorubicin

Determination of Immunoglobulin Y Concentration in Yolk Extract Prepared by Water Dilution Method: Comparisons among Three Strains of Chickens

In avian species, immunoglobulin Y (IgY) is found abundantly in egg yolk as well as in blood. Although the concentration of IgY in yolk has been previously reported by many investigators, the reported IgY concentrations have varied from 1 to 25mg/g yolk. In the present study, we determined yolk IgY concentration in three strains of chickens, taking into consideration the IgY recovery rate in yolk extract; in addition, we estimated the concentration factor of yolk IgY against plasma IgY. Egg yolk and plasma samples were collected from two commercial layers, Dekalb and Nagoya, and one inbred strain, PNP/DO. Extraction of yolk IgY was followed by the water dilution method reported by Akita and Nakai (Journal of Food Science 57, 629-634, 1992) with minor modification, and IgY concentration was measured by ELISA. The recovery of IgY from the yolk was in the 50 to 60% range, and no significant difference was observed among the strains. PNP/DO showed the highest concentration of IgY expressed as mg/g yolk (12.2), and Dekalb and Nagoya had almost the similar concentration of IgY (Dekalb, 6.2; Nagoya, 5.7). In all strains, the concentration of plasma IgY was proportional to that of yolk IgY, and the concentration factor of yolk IgY against plasma IgY was approximately 0.8. On the other hand, when the yolk IgY concentration was expressed as mg/mL water in yolk, the concentration factor of yolk IgY against plasma IgY represented approximately 1.7 regardless of the strains. Taken together, our findings suggest that the concentration of IgY in the yolk should be determined by considering the recovery rate during the process of IgY extraction; in addition, it raised the possibility that blood IgY might be concentrated in egg yolks of chickens

Characteristics of retinal reflectance changes induced by transcorneal electrical stimulation in cat eyes.

Transcorneal electrical stimulation (TES) activates retinal neurons leading to visual sensations. How the retinal cells are activated by TES has not been definitively determined. Investigating the reflectance changes of the retina is an established technique and has been used to determine the mechanism of retinal activation. The purpose of this study was to evaluate the reflectance changes elicited by TES in cat eyes. Eight eyes of Eight cats were studied under general anesthesia. Biphasic electrical pulses were delivered transcornealy. The fundus images observed with near-infrared light (800-880 nm) were recorded every 25 ms for 26 s. To improve the signal-to-noise ratio, the images of 10 consecutive recordings were averaged. Two-dimensional topographic maps of the reflective changes were constructed by subtracting images before from those after the TES. The effects of different stimulus parameters, e.g., current intensity, pulse duration, frequency, and stimulus duration, on the reflective changes were studied. Our results showed that after TES, the reflective changes appeared on the retinal vessels and optic disc. The intensity of reflectance changes increased as the current intensity, pulse duration, and stimulation duration increased (P<0.05 for all). The maximum intensity of the reflective change was obtained when the stimulus frequency was 20 Hz. The time course of the reflectance changes was also altered by the stimulation parameters. The response started earlier and returned to the baseline later with higher current intensities, longer pulse durations, but the time of the peak of the response was not changed. These results showed that the reflective changes were due to the activation of retinal neurons by TES and might involve the vascular changes induced by an activation of the retinal neurons

Production of a selective antibacterial fatty acid against Staphylococcus aureus by Bifidobacterium strains

Aims: C16 monounsaturated fatty acid (C16:1) show antibacterial activity against Staphylococcus aureus, a pathogen associated with various diseases such as atopic dermatitis and bacteremia, while the compound does not exhibit antibacterial activity against Staphylococcus epidermidis, an epidermal commensal that inhibits the growth of S. aureus. In this study, we aimed to find bifidobacterial strains with the ability to produce C16:1 and to find a practical manner to utilize C16:1-producing strains in industry.Methods: Various Bifidobacterium strains were screened for their content of C16:1. The chemical identity of C16:1 produced by a selected strain was analyzed by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS). Medium components that affect the C16:1 content of the selected strain were investigated. Antibacterial activity against staphylococci was compared between the authentic C16:1 isomers and total fatty acids (TFA) extracted from the selected strain.Results: B. adolescentis 12451, B. adolescentis 12-111, B. boum JCM 1211, and Bifidobacterium sp. JCM 7042 showed high C16:1 content among the tested strains. TFA extracted from Bifidobacterium sp. JCM 7042 contained C16:1 at 2.3% as the fatty acid constituent (2.4 mg/L of broth). Through GC-MS and LC-MS analyses, the C16:1 synthesized by Bifidobacterium sp. JCM 7042 was identified as 7-cis-hexadecenoic acid (7-cis-C16:1). The authentic 7-cis-C16:1 showed strong and selective antibacterial activity against S. aureus, similar to 6-cis-C16:1, with a minimum inhibitory concentration (MIC) of &lt; 10 µg/mL. Components that increase C16:1 productivity were not found in the MRS and TOS media; however, Tween 80 was shown to considerably reduce the C16:1 ratio in TFA. Antibacterial activity against S. aureus was observed when the TFA extracted from Bifidobacterium sp. JCM 7042 contained high level of 7-cis-C16:1 (6.1% in TFA) but not when it contained low level of 7-cis-C16:1 (0.1% in TFA).Conclusion: The fatty acid, 7-cis-C16:1, which can selectively inhibit the S. aureus growth, is accumulated in TFA of several bifidobacteria. The TFA extracted from cultured cells of Bifidobacterium sp. JCM 7042 demonstrated antibacterial activity. From a practical viewpoint, our findings are important for developing an efficient method to produce novel skin care cosmetics, functional dairy foods, and other commodities

Deep-learning approach to detect childhood glaucoma based on periocular photograph

Abstract Childhood glaucoma is one of the major causes of blindness in children, however, its diagnosis is of great challenge. The study aimed to demonstrate and evaluate the performance of a deep-learning (DL) model for detecting childhood glaucoma based on periocular photographs. Primary gaze photographs of children diagnosed with glaucoma with appearance features (corneal opacity, corneal enlargement, and/or globe enlargement) were retrospectively collected from the database of a single referral center. DL framework with the RepVGG architecture was used to automatically recognize childhood glaucoma from photographs. The average receiver operating characteristic curve (AUC) of fivefold cross-validation was 0.91. When the fivefold result was assembled, the DL model achieved an AUC of 0.95 with a sensitivity of 0.85 and specificity of 0.94. The DL model showed comparable accuracy to the pediatric ophthalmologists and glaucoma specialists in diagnosing childhood glaucoma (0.90 vs 0.81, p = 0.22, chi-square test), outperforming the average of human examiners in the detection rate of childhood glaucoma in cases without corneal opacity (72% vs. 34%, p = 0.038, chi-square test), with a bilateral corneal enlargement (100% vs. 67%, p = 0.03), and without skin lesions (87% vs. 64%, p = 0.02). Hence, this DL model is a promising tool for diagnosing missed childhood glaucoma cases