Evaluation of the in vitro and in vivo antimicrobial activity of alkaloids prepared from Chelidonium majus L. using MRSA- infected C. elegans as a model host.

Chelidonium majus L. contained alkaloids as its main component, exhibiting various biological activities, particularly antibacterial activity. This study aimed to extract alkaloids from C. majus L. (total alkaloids) and evaluate their antibacterial activity both in vitro and in vivo. Reflux extraction was carried out on C. majus L., and the extract was purified with HPD-600 macroporous resin and 732 cation exchange resin columns. Infection modeling of Caenorhabditis elegans (C. elegans) was established to investigate the impact of Methicillin-resistant Staphylococcus aureus (MRSA) and Methicillin-sensitive Staphylococcus aureus (MSSA) on the motility, longevity, and reactive oxygen species (ROS) levels of wild-type worms (N2 strain). The effects of total alkaloids on longevity and ROS were further evaluated in infected N2 worms. Additionally, the effect of total alkaloids on the stress resistance of C. elegans and the mechanism of action were investigated. By utilizing CB1370, DR26 and CF1038 transgenic strains of C. elegans to identify whether the antibacterial activity of total alkaloids was dependent on DAF-2/DAF-16 pathway. The results showed that total alkaloids exhibited a significant antibacterial activity against both MRSA and MSSA (MIC 31.25 µg/mL). Compared with MSSA, the MRSA exhibited a stronger inhibitory effect on the movement behavior and development of worms, along with faster pathogenicity and unique virulence factors. Total alkaloids also displayed the ability to extend the lifespan of C. elegans under oxidative stress and heat stress, and reduce the expression of ROS. The antibacterial activity of total alkaloids was primarily dependent on the DAF-2/DAF-16 pathway, and the presence of functional DAF-2 was deemed essential in total alkaloids mediated immune response against MRSA. Moreover, the antibacterial and anti-infection effects of total alkaloids were found to be associated with the daf-16 gene fragment.

Glycine regulates mucosal immunity and the intestinal microbial composition in weaned piglets.

Glycine is an amino acid with a diverse array of health benefits regarding metabolism, immunity, and development. The aim of this study was to test the hypothesis that glycine supplementation alters the intestinal microbial composition and improves the intestinal mucosal immunity of weaned piglets. One hundred and twenty-eight weaned piglets divided into 4 groups were fed with a corn- and soybean meal-based diet supplemented with 0 (control), 0.5, 1, or 2% glycine for 7 days. The intestinal microbiota and tissue samples from the control and the 2% glycine-supplemented piglets were collected for determination of the composition of microbial community and the intestinal mucosal barrier function. Piglets fed with diet containing 2% glycine, instead of 0.5% or 1% glycine, presented elevated average daily gain and feed conversion ratio, as compared with the control. 2% glycine enhanced the abundance of mucins in the jejunum and ileum and mRNA level of porcine ß-defensin (pBD) 2 and pBD-3, as well as the protein level of secretory immunoglobulin A (sIgA) in the jejunum. The mRNA expression of tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, and IL-6, and the protein level of phosphorylated p38 mitogen-activated protein kinase (MAPK), signal transducer and activator of transcription 3 (STAT3), nuclear factor (NF)-κB p65, and claudin-2 in the jejunum were lower in the 2% glycine group than that in the control. In addition, an elevated ratio of CD4+/CD8+ T lymphocytes was observed in the jejunum of piglets receiving diet supplemented with 2% glycine. The colon content of piglets fed with 2% glycine exhibited a reduction in abundance of pathogenic bacteria (Escherichia-Shigella, Clostridium, and Burkholderiales) and an increase in short-chain fatty acid-producing bacteria (Blautia, Lachnospiraceae, Anaerostipes, and Prevotella) in comparison with the control. We conclude that dietary supplementation with 2% glycine improves the intestinal immunological barrier function and the microbial composition, therefore, contributing to the growth performance of weaned piglets.

[Research progress on terpenes and pharmacological effects of Saussurea lappa].

Saussurea lappa originates in India, and now mainly grow in Yunnan, Sichuan and other places in China. It is one of the commonly used traditional herbal medicines in Tibet and other minority regions, with effects in regulating qi to relieve pain and invigo-rating spleen to promote food. It has been used in clinic for gastrointestinal diseases, such as Qi stagnation syndrome of spleen and stomach, diarrhea and tenesmus. More than 200 compounds have been identified from S. lappa. Among them, sesquiterpenoids attracted much attention. In terms of the number of compounds, eudesmanetype is dominant, guaiane and germacranetypes have also been reported frequently. Pharmacological studies have involved extracts, volatile oils and monomeric components represented by dehydrocostus lactone. Anti-tumor, anti-inflammatory and anti-bacterial effects on digestive system have attracted great attention. However, due to the complex sources of S. lappa and widely used in clinical practice, there is few research progress on relevant chemical constituents and pharmacological activities. This paper systematically summarizes terpenes and the pharmacological effects of S. lappa, in order to provide basis for further studies and clinical applications.

l-Glutamine Represses the Unfolded Protein Response in the Small Intestine of Weanling Piglets.

BACKGROUND: Dysfunction of the endoplasmic reticulum (ER) results in apoptosis, inflammation, and enhanced proteolysis in the small intestine of humans and animals. l-Glutamine (Gln) is required for intestinal mucosal homeostasis in piglets. However, a functional role of the ER in the enterocytes of weanling piglets and its contribution to intestinal mucosal integrity remain largely unknown. OBJECTIVE: This study was conducted to test the hypothesis that preweaning administration of Gln alleviates the activation of unfolded protein response (UPR) in the small intestine of weanling piglets. METHODS: Eighteen sow-reared piglets aged 7 d from 3 litters (6 piglets/litter) were assigned randomly into 1 of 3 treatment groups. Piglets were reared by sows until age 24 d, or were reared by sows and orally administered either l-alanine [1.84 g · kg body weight (BW)-1 · d-1] or Gln (1.52 g · kg BW-1 · d-1) twice daily between 7 and 21 d of age, and then weaned to a corn- and soybean meal-based diet. The small-intestinal samples were collected at 24 d of age for analyses of abundance of proteins related to ER stress and apoptosis, concentrations of inflammatory cytokines, and mRNA abundance for genes implicated in protein degradation. RESULTS: Compared with age-matched suckling piglets, weaning stress increased apoptosis and decreased cell proliferation in the jejunum. The abundance of proteins related to ER stress [binding immunoglobulin protein, activating transcription factor 6α, phosphorylated (p)-inositol-requiring kinase 1α, and p-eukaryotic initiation factor 2α] was elevated by 200% to 320%, and that of apoptotic proteins (CCAAT/enhancer-binding protein homologous protein, p-Jun-N-terminal kinase, caspase-12, cleaved caspase-3, and Bcl-2-associated X) was augmented by 100% to 350% in the jejunum of weanling piglets. The protein abundance for IL-1ß, TNF-α, and IL-8 was increased by 100% to 230% in the jejunum of weanling piglets. These alterations in gene and protein expression were markedly abrogated by Gln supplementation. The mRNA concentration of F-Box protein 32 in the jejunum of weanling piglets was increased by 70%, compared with the control group, and was not affected by Gln supplementation. CONCLUSION: Our results indicate that preweaning administration of Gln to nursing piglets alleviates the weaning-activated UPR.

Glycine supplementation to breast-fed piglets attenuates post-weaning jejunal epithelial apoptosis: a functional role of CHOP signaling.

This study was conducted to test the hypothesis that preweaning  glycine supplementation to breast-fed piglets alleviated the post-weaning  apoptosis of jejunal epithelium through CHOP signaling. Seven-day-old sow-reared piglets were orally administrated with 0, 50, 100, or 200% of glycine intake from sow's milk twice daily for 14 days and then were weaned at 21 days of age. Tissue samples were collected at 28 days of age for determining intestinal morphology, serum diamine oxidase (DAO) activity, abundances of proteins involved in ER stress and apoptosis. Glycine (100-200%) administration increased villus height, the ratio of villus height to crypt depth in the jejunum. Glycine supplementation (200%) enhanced average daily weight gain during the first 2 weeks post-weaning. Serum DAO activity and jejunal epithelium apoptosis were decreased, but the number of goblet cells in the jejunum was increased. Western blot analysis showed that 100-200% glycine enhanced the protein levels of occludin, claudin-1, and zonula occludens (ZO)-1 without affecting those of claudin-3, ZO-2, and ZO-3. Further studies showed that protein abundances of glucose-regulated protein 78 (BiP/GRP78) and p-IRE1α, instead of ATF6α, were reduced by glycine. Among the proteins related to apoptosis, abundances of CHOP and p53 were reduced, whereas those of Bcl-2 and Bcl-xL were enhanced in the jejunum of 100-200% glycine-supplemented piglets. Collectively, our results indicated that preweaning glycine supplementation improved the intestinal development of post-weaning piglets. The beneficial effect of glycine was associated with improved intestinal mucosal barrier and reduced apoptosis of enterocytes through CHOP signaling.

Vitamin A Deficiency Impairs Mucin Expression and Suppresses the Mucosal Immune Function of the Respiratory Tract in Chicks.

The chicken immune system is immature at the time of hatching. The development of the respiratory immune system after hatching is vital to young chicks. The aim of this study was to investigate the effect of dietary vitamin A supplement levels on respiratory mucin and IgA production in chicks. In this study, 120 one-day-old broiler chicks were randomly divided into 4 groups consisting of three replicates of 10 broilers and subjected to dietary vitamin A supplement levels of 0, 1,500, 6,000, or 12,000 IU/kg for seven days. Compared with control birds, vitamin A supplementation significantly increased the mucin and IgA levels in the bronchoalveolar lavage fluid (BALF) as well as the IgA level in serum. In the lungs, vitamin A supplementation downregulated TNF-α and EGFR mRNA expression. The TGF-ß and MUC5AC mRNA expression levels were upregulated by vitamin A supplementation at a dose of 6,000 IU/kg, and the IL-13 mRNA expression level was increased at the 12,000 IU/kg supplement level. Vitamin A deficiency (control) significantly decreased the mRNA expression levels of MUC2, IgA, EGFR, IL-13 and TGF-ß in trachea tissue. Histological section analysis revealed that the number of goblet cells in the tracheal epithelium was less in the 0 and 12,000 IU/kg vitamin A supplement groups than in the other groups. In conclusion, vitamin A deficiency suppressed the immunity of the airway by decreasing the IgA and mucin concentrations in neonatal chicks. This study suggested that a suitable level of vitamin A is essential for the secretion of IgA and mucin in the respiratory tract by regulating the gene expression of cytokines and epithelial growth factors.