Corrigendum: Genetic liability for diet-derived circulating antioxidants, oxidative stress, and risk of osteoarthritis: a Mendelian randomization study.

[This corrects the article DOI: 10.3389/fnut.2023.1233086.].

Prostaglandin D2 is involved in the regulation of inflammatory response in Staphylococcus aureus-infected mice macrophages.

Staphylococcus aureus (S. aureus) is one of the most infamous and widespread bacterial pathogens, causing a hard-to-estimate number of uncomplicated skin infections and probably hundreds of thousands to millions of more severe, invasive infections globally per year. S. aureus may also be acquired from animals, especially in the livestock industry. The interaction mechanism of host and S. aureus has significance for finding ways to against S. aureus infection and control inflammatory response of host, while the molecular biological activities after S. aureus infection, particular in inflammatory and immune cells are not fully clear. The present study aimed to explore whether pattern recognition receptors (PRRs) mediate prostaglandin D2 (PGD2) synthesis and PGD2 participates in the regulation of inflammatory response in macrophages during S. aureus infection or synthetic bacterial lipopeptide (Pam2CSK4) stimulation. PGD2 secretion level was enhanced by mice peritoneal macrophages infected with the S. aureus. The results indicated that PGD2 secretion was impaired in S. aureus infected-macrophages from toll-like receptors 2 (TLR2)-deficient and NLR pyrin domain-containing 3 (NLRP3)-deficient mice. PGD2 synthetase (hematopoietic PGD synthase, HPGDS) inhibitors could reduce the activation of macrophage mitogen-activated protein kinase (MAPK)/nuclear factor-κ-gene binding (NF-κB) signaling pathways. HPGDS inhibition impaired cytokines (TNF-α, IL-1ß, IL-10 and RANTES) secretion and macrophage phagocytosis during S. aureus infection. In addition, inhibition of endogenous PGD2 synthesis was unable to affect the TLR2 and NLRP3 expression in S. aureus-infected macrophages. Taken together, macrophage PGD2 secretion after S. aureus infection depended on receptors TLR2 and NLRP3, and the induced PGD2 participated in the regulation of inflammatory response in S. aureus-infected macrophages. Interestingly, it was found that exogenous PGD2 down-regulated the cytokines secretion and had no effect on phagocytosis in the S. aureus-infected macrophages.

Prostaglandin D2 regulates Escherichia coli-induced inflammatory responses through TLR2, TLR4, and NLRP3 in macrophages.

Prostaglandin D2 (PGD2) synthesis is closely associated with the innate immune response mediated by pattern recognition receptors (PPRs). We determined PGD2 synthesis whether mediated by Toll-like receptor 2 (TLR2), TLR4 and Nod-like receptor pyrin domain-containing protein 3 (NLRP3) in Escherichia coli (E. coli)-, lipopolysaccharide (LPS)- and Braun lipoprotein (BLP)-stimulated macrophages. Our data demonstrate that TLR2, TLR4, and NLRP3 could regulate the synthesis of PGD2 through cyclo-oxygenase-2 (COX-2) and hematopoietic PGD synthase (H-PGDS) in E. coli-, LPS- or BLP-stimulated macrophages, suggesting that TLR2, TLR4, and NLRP3 are critical in regulating PGD2 secretion by controlling PGD2 synthetase expression in E. coli-, LPS- or BLP-stimulated macrophages. The H-PGDS (a PGD2 specific synthase) inhibitor pre-treatment could down-regulate the secretion of TNF-α, RANTES and IL-10 in LPS- and E. coli-stimulated macrophage. Meanwhile, H-PGDS inhibitor could down-regulate the secretion of TNF-α, while up-regulated RANTES and IL-10 secretion in BLP-stimulated macrophages, suggesting that PGD2 could regulate the secretion of cytokines and chemokines in E. coli-, LPS- or BLP-stimulated macrophages. Furthermore, exogenous PGD2 regulates the secretion of cytokines and chemokines through activation of MAPK and NF-κB signaling pathways after E. coli-, LPS- or BLP stimulation in macrophages. Taken together, PGD2 is found able to regulate E. coli-induced inflammatory responses through TLR2, TLR4, and NLRP3 in macrophages.

Does ghrelin regulate intestinal motility in rabbits? An in vitro study using isolated duodenal strips.

Rabbit duodenum has been used for examining the ability of motilin to cause muscle contraction in vitro. A motilin-related peptide, ghrelin, is known to be involved in the regulation of gastrointestinal (GI) motility in various animals, but its ability to cause rabbit GI contraction have not been well examined. The aim of this study is to clarify the action of rat ghrelin and its interaction with motilin in the rabbit duodenum. The mRNA expression of ghrelin and motilin receptors was also examined using RT-PCR. Rat ghrelin (10-9-10-6 M) did not change the contractile activity of the duodenum measured by the mean muscle tonus and area under the curve of contraction waves. In agreement with this result, the distribution of ghrelin receptor mRNA in the rabbit GI tract varied depending on the GI region from which the samples were taken; the expression level in the duodenum was negligible, but that in the esophagus or stomach was significant. On the other hand, motilin (10-10-10-6 M) caused a concentration-dependent contraction by means of increased mean muscle tonus, and consistently, motilin receptor mRNA was expressed heterogeneously depending on the GI region (esophagus = stomach = colon = rectum < duodenum = jejunum = ileum < cecum). Expression level of motilin receptor was comparable to that of ghrelin receptor in the esophagus and stomach. Pretreatment with ghrelin (10-6 M) prior to motilin did not affect the contractile activity of motilin in the duodenum. In conclusion, ghrelin does not affect muscle contractility or motilin-induced contraction in the rabbit duodenum, which is due to the lack of ghrelin receptors. The present in vitro results suggest that ghrelin might not be a regulator of intestinal motility in rabbits.

Besides TLR2 and TLR4, NLRP3 is also involved in regulating Escherichia coli infection-induced inflammatory responses in mice.

The host Toll-like Receptor-2 (TLR2) and Toll-like Receptor-4 (TLR4) play critical roles in defense against Escherichia coli (E. coli) infection is well-known. The NLR pyrin domain-containing 3 (NLRP3) inflammasome is also an important candidate during the host-recognized pathogen, while the roles of NLRP3 in the host inflammatory response to E. coli infection remains unclear. This study aimed to explore the roles of NLRP3 in regulating the inflammatory response in E. coli infection-induced mice. Our result indicated that compared to wild-type mice, the TLR2-deficient (TLR2-/-), TLR4-deficient (TLR4-/-), and NLRP3-deficient (NLRP3-/-) mice had significant decrease in liver damage after stimulation with Lipopolysaccharide (LPS, 1 µg/mL), Braun lipoprotein (BLP, 1 µg/mL), or infected by WT E. coli (1 × 107 CFU, MOI 5:1). Meanwhile, compared with wild-type mice, the TNF-α and IL-1ß production in serum decreased in TLR2-/-, TLR4-/-, and NLRP3-/- mice after LPS, BLP treatment, or WT E. coli infection. In macrophages from NLRP3-/- mice showed significantly reduced secretion of TNF-α and IL-1ß in response to stimulation with LPS, BLP, or WT E. coli infection compared with macrophages from wild-type mice. These results indicate that besides TLR2 and TLR4, NLRP3 also plays a critical role in host inflammatory responses to defense against E. coli infection, and might provide a therapeutic target in combating disease with bacterium infection.

Staphylococcus aureus increases Prostaglandin E2 secretion in cow neutrophils by activating TLR2, TLR4, and NLRP3 inflammasome signaling pathways.

Introduction: In clinical settings, dairy cows are often attacked by pathogenic bacteria after delivery, especially Staphylococcus aureus (S. aureus). Neutrophils have long been regarded as essential for host defense against S. aureus. Prostaglandin E2 (PGE2) can additionally be used as an inflammatory mediator in pathological conditions to promote the repair of inflammatory injuries. However, whether S. aureus can promote the accumulation of PGE2 after the infection of neutrophils in cows and its mechanism remain unclear. Lipoprotein is an important immune bioactive ingredient of S. aureus. Methods: In this study, the changes in neutrophils were monitored in dairy cows infected with wild-type S. aureus (SA113) and an S. aureus lipoprotein-deficient strain (Δlgt); meanwhile, we established whether pattern recognition receptors mediate this process and whether S. aureus lipoproteins are necessary for causing the release of PGE2 from cow neutrophils. Results: The results showed that Δlgt was less effective than SA113 in inducing the production of IL-1ß, IL-6, IL-8, IL-10, and PGE2 within neutrophils; furthermore, TLR2, TLR4, and NLRP3 receptors were found to mediate the inducible effect of lipoprotein on the above inflammation mediators and cytokines, which depended on MAPK and Caspase-1 signaling pathways. In addition, TLR2, TLR4, and NLRP3 inhibitors significantly inhibited PGE2 and cytokine secretion, and PGE2 was involved in the interaction of S. aureus and neutrophils in dairy cows, which could be regulated by TLR2, TLR4, and NLRP3 receptors. We also found that S. aureus was more likely to be killed by neutrophils when it lacked lipoprotein and TLR2, TLR4, and NLRP3 were involved, but PGE2 seemed to have no effect. Discussion: Taken together, these results suggest that lipoprotein is a crucial component of S. aureus in inducing cytokine secretion by neutrophils as well as killing within neutrophils, which could be accomplished by the accumulation of PGE2 by activating MAPK and the Caspase-1 signaling pathways through TLR2, TLR4, and NLRP3 receptors. These results will contribute to a better understanding of the interaction between S. aureus and host immune cells in dairy cows.

Genetically supported causality between gut microbiota, gut metabolites and low back pain: a two-sample Mendelian randomization study.

Background: Previous studies have implicated a vital association between gut microbiota/gut microbial metabolites and low back pain (LBP), but their causal relationship is still unclear. Therefore, we aim to comprehensively investigate their causal relationship and identify the effect of gut microbiota/gut microbial metabolites on risk of LBP using a two-sample Mendelian randomization (MR) study. Methods: Summary data from genome-wide association studies (GWAS) of gut microbiota (18,340 participants), gut microbial metabolites (2,076 participants) and LBP (FinnGen biobank) were separately obtained. The inverse variance-weighted (IVW) method was used as the main MR analysis. Mendelian randomization pleiotropy residual sum and outlier (MR-PRESSO) and MR-Egger regression were conducted to evaluate the horizontal pleiotropy and to eliminate outlier single-nucleotide polymorphisms (SNPs). Cochran's Q-test was applied for heterogeneity detection. Besides, leave-one-out analysis was conducted to determine whether the causal association signals were driven by any single SNP. Finally, a reverse MR was performed to evaluate the possibility of reverse causation. Results: We discovered that 20 gut microbial taxa and 2 gut microbial metabolites were causally related to LBP (p < 0.05). Among them, the lower level of family Ruminococcaceae (OR: 0.771, 95% CI: 0.652-0.913, FDR-corrected p = 0.045) and Lactobacillaceae (OR: 0.875, 95% CI: 0.801-0.955, FDR-corrected p = 0.045) retained a strong causal relationship with higher risk of LBP after the Benjamini-Hochberg Corrected test. The Cochrane's Q test revealed no Heterogeneity (p > 0.05). Besides, MR-Egger and MR-PRESSO tests showed no significant horizontal pleiotropy (p > 0.05). Furthermore, leave-one-out analysis confirmed the robustness of MR results. After adding BMI to the multivariate MR analysis, the 17 gut microbial taxa exposure-outcome effect were significantly attenuated and tended to be null. Conclusion: Our findings confirm the the potential causal effect of specific gut microbiota and gut microbial metabolites on LBP, which offers new insights into the gut microbiota-mediated mechanism of LBP and provides the theoretical basis for further explorations of targeted prevention strategies.

Braun Lipoprotein Protects against Escherichia coli-Induced Inflammatory Responses and Lethality in Mice.

Escherichia coli (E. coli), a Gram-negative bacterium, is an important pathogen that causes several mammalian diseases. The outer membrane components of E. coli, namely, lipopolysaccharide (LPS) and bacterial lipoprotein, can induce the host innate immune response through pattern recognition receptors (PRRs). However, the detailed roles of the E. coli Braun lipoprotein (BLP) in the regulation of host inflammatory response to E. coli infection remain unclear. In this study, we sought to determine the effects of BLP on E. coli-induced host inflammatory response and lethality using mouse models. Experiments using the E. coli DH5α strain (BLP-positive), E. coli JE5505 strain (BLP-negative), and E. coli JE5505 strain combined with BLP indicated that the presence of BLP could alleviate mortality and organ (liver and lung) damage and decrease proinflammatory cytokine (tumor necrosis factor alpha [TNF-α] and interleukin-1ß [IL-1ß]) and chemokine (regulated on activation normal T-cell expressed and secreted [RANTES]) production in mouse serum and organs. Conversely, E. coli JE5505, E. coli DH5α strain, and E. coli JE5505 combined with BLP treatment induce enhanced anti-inflammatory cytokine (interleukin 10 [IL-10]) production in mouse serum and organs. In addition, BLP could regulate the secretion of proinflammatory cytokines (TNF-α and IL-1ß), chemokines (RANTES), and anti-inflammatory factors (IL-10) through mitogen-activated protein kinase (MAPK) and nuclear factor-kappaB (NF-κB) signaling pathways in macrophages. Altogether, our results demonstrate that the bacterial component BLP plays crucial and protective roles in E. coli-infected mice, which may influence the outcome of inflammation in host response to E. coli infection. IMPORTANCE In this study, we investigated the roles of bacterial outer membrane component BLP in regulating inflammatory responses and lethality in mice that were induced by a ubiquitous and serious pathogen, Escherichia coli. BLP could alleviate the mortality of mice and organ damage, as well as decrease proinflammatory cytokines and chemokine production and enhance anti-inflammatory cytokine production in mouse serum and organs. Overall, our results demonstrate that the bacterial component BLP plays crucial and protective roles in E. coli-infected mice through regulating the production of an inflammatory mediator, which may influence the outcome of inflammation in host response to E. coli infection. Our findings provide new information about the basic biology involved in immune responses to E. coli and host-bacterial interactions, which have the potential to translate into novel approaches for the diagnosis and treatment of E. coli-related medical conditions, such as bacteremia and sepsis.

Multisite chronic pain and the risk of autoimmune diseases: A Mendelian randomization study.

Background: Accumulating evidence has demonstrated that an association between chronic pain and autoimmune diseases (AIDs). Nevertheless, it is unclear whether these associations refer to a causal relationship. We used a two-sample Mendelian randomization (MR) method to determine the causal relationship between chronic pain and AIDs. Methods: We assessed genome-wide association study (GWAS) summary statistics for chronic pain [multisite chronic pain (MCP) and chronic widespread pain (CWP)], and eight common AIDs, namely, amyotrophic lateral sclerosis (ALS), celiac disease (CeD), inflammatory bowel disease (IBD), multiple sclerosis (MS), rheumatoid arthritis (RA), systemic lupus Erythematosus (SLE), type 1 diabetes (T1D) and psoriasis. Summary statistics data were from publicly available and relatively large-scale GWAS meta-analyses to date. The two-sample MR analyses were first performed to identify the causal effect of chronic pain on AIDs. The two-step MR and multivariable MR were used to determine if mediators (BMI and smoking) causally mediated any connection and to estimate the proportion of the association mediated by these factors combined. Results: With the utilization of MR analysis, multisite chronic pain was associated with a higher risk of MS [odds ratio (OR) = 1.59, 95% confidence interval (CI) = 1.01-2.49, P = 0.044] and RA (OR = 1.72, 95% CI = 1.06-2.77, P = 0.028). However, multisite chronic pain had no significant effect on ALS (OR = 1.26, 95% CI = 0.92-1.71, P = 0.150), CeD (OR = 0.24, 95% CI = 0.02-3.64, P = 0.303), IBD (OR = 0.46, 95% CI = 0.09-2.27, P = 0.338), SLE (OR = 1.78, 95% CI = 0.82-3.88, P = 0.144), T1D (OR = 1.15, 95% CI = 0.65-2.02, P = 0.627) or Psoriasis (OR = 1.59, 95% CI = 0.22-11.26, P = 0.644). We also found positive causal effects of MCP on BMI and causal effects of BMI on MS and RA. Moreover, there were no causal connections between genetically predicted chronic widespread pain and the risk of most types of AIDs disease. Conclusion: Our MR analysis implied a causal relationship between MCP and MS/RA, and the effect of MCP on MS and RA may be partially mediated by BMI.

Motilin is a regulator of gastric contraction in Japanese fire belly newts (Cynops pyrrhogaster), in vitro studies using isolated gastrointestinal strips of newts, rabbits, and chickens.

The effects of newt motilin on the contractility of the isolated gastrointestinal (GI) tract from Japanese fire belly newts (newt) were examined to clarify whether motilin regulates GI motility in urodele amphibians. In addition, contractile responsiveness to motilins from seven species of vertebrates (human, chicken, turtle, alligator, axolotol, newt and zebrafish) were compared in GI preparations from three different animals (rabbit duodenum, chicken ileum and newt stomach) to determine the species-specific action of motilin. Newt motilin (10-10 M - 10-6 M) caused a contraction of cognate gastric strips, while the upper, middle, and lower intestinal strips were insensitive. The rank order of motilins for contractile activity in newt gastric strips was newt > alligator > axolotol > chicken > turtle > human ≫ zebrafish. On the other hand, newt motilin caused a weak contraction in the rabbit duodenum (human > alligator = chicken > turtle > newt ≧ axolotol > zebrafish), and it was ineffective in the chicken ileum (chicken > turtle > alligator > human ≫ newt, axolotol and zebrafish). This study demonstrates that motilin induces contraction in the GI tract of a urodele amphibian, the newt, in a region (stomach)-specific manner and further indicates that a ligand-receptor interaction of the motilin system is a species-specific manner probably due to differences in the amino acid sequence of motilin.

Genetic liability for diet-derived circulating antioxidants, oxidative stress, and risk of osteoarthritis: a Mendelian randomization study.

Background: Although well-documented, the causal relationships between diet-derived circulating antioxidants, oxidative stress, and osteoarthritis (OA) are equivocal. The objective of this study is to employ two-sample Mendelian randomization (MR) to investigate possible causal relationships among dietary-derived circulating antioxidants, oxidative stress damage indicators, and OA risk. Methods: Single-nucleotide polymorphisms for diet-derived circulating antioxidants (ascorbate, ß-carotene, lycopene, retinol, and α-and γ-tocopherol), assessed as absolute levels and metabolites, as well as oxidative stress injury biomarkers (GSH, GPX, CAT, SOD, albumin, and total bilirubin), were retrieved from the published data and were used as genetic instrumental variables. Summary statistics for gene-OA associations were obtained from publicly available and two relatively large-scale GWAS meta-analyses to date. The inverse-variance weighting method was utilized as the primary MR analysis. Moreover, multivariable MR was used to determine if mediators (BMI and smoking) causally mediated any connection. Furthermore, for each exposure, MR analyses were conducted per outcome database and then meta-analyzed. Results: Genetically predicted absolute retinol level was causally associated with hip OA risk [odds ratios (ORs) = 0.40, 95% confidence interval (CI) = 0.24-0.68, FDR-corrected p = 0.042]. Moreover, genetically predicted albumin level was causally associated with total OA risk (OR = 0.80, 95% CI = 0.75-0.86, FDR-corrected p = 2.20E-11), as well as the risk of hip OA (OR = 0.75, 95% CI = 0.68-0.84, FDR-corrected p = 1.38E-06) and knee OA (OR = 0.82, 95% CI = 0.76-0.89, FDR-corrected p = 4.49E-06). In addition, MVMR confirmed that the effect of albumin on hip OA is independent of smoking initiation, alcoholic drinks per week, and moderate-to-vigorous physical activity levels but may be influenced by BMI. Conclusion: Evidence from our study supports a potentially protective effect of high levels of retinol and albumin on OA risk.

Prostaglandin E receptor 2 mediates the inducible effects of prostaglandin E2 on expression of growth factors and enzymes in cattle endometrial epithelial cells and explants.

Prostaglandin E2 (PGE2 ) is able to induce the expression of several growth factors and enzymes in cattle endometria. However, the specific type of PGE2 receptors which mediates this effect is not fully clear. In this study, the role of prostaglandin E receptor 2 (PTGER2) in PGE2 -mediated induction of growth factors and enzymes expression in cattle endometrial explants and epithelial cells were investigated. PTGER2 was blocked by a PTGER2 antagonist, AH6809, before PGE2 treatment, then the mRNA and protein expression levels of several growth factors and enzymes were compared with that in PGE2 alone treatment group by real-time RT-PCR and Western blotting analysis in endometrial epithelial cells and explants. Results indicated that PGE2 significantly increased the mRNA and protein levels of these growth factors and enzymes, while the rates of increment in the expression of these growth factors and enzymes were inhibited by AH6809. In addition, a PTGER2 agonist, butaprost, significantly increased the expression levels of these growth factors and enzymes, and the effect could be blocked by AH6809. In conclusion, PTGER2 was found to be one dominant receptor mediating the inducible effects of PGE2 on the expression of these growth factors and enzymes in cattle endometrial explants and epithelial cells.

TLR2, TLR4, and NLRP3 mediated the balance between host immune-driven resistance and tolerance in Staphylococcus aureus-infected mice.

Staphylococcus aureus (S. aureus) is a gram-positive pathogen that can cause infectious diseases in mammals. S. aureus-induced host innate immune responses have a relationship with Toll-like receptor 2 (TLR2), TLR4, and Nod-like receptor pyrin domain-containing protein 3 (NLRP3). However, the detailed roles of TLR2, TLR4, and NLRP3 in regulating the host inflammatory response to S. aureus infection remain unclear. Our data indicated that the S. aureus-induced mortality was aggravated by deficiency of TLR2, TLR4, and NLRP3 in mice. In the subsequent experiment, we found that during S. aureus infection, the roles of TLR2, TLR4, and NLRP3 seemed to be different at multiple timepoints. The deficiency of TLR2, TLR4, or NLRP3 attenuated the expression of High-mobility group box protein 1 (HMGB1) and Hyaluronic acid-binding protein 2 (HABP2), which is accompanied by decreased proinflammatory cytokine (TNF-α), chemokine (RANTES), and anti-inflammatory cytokine (IL-10) production in lungs and serum at 3 h and 6 h post-infection. However, with S. aureus infection prolonged (24 h post-infection), the trend was diametrically opposite. The results showed that deficiency of TLR2, TLR4, or NLRP3 aggravated HABP2 and HMGB1 expression, which is accompanied by enhanced proinflammatory cytokine (TNF-α), chemokine (RANTES), and anti-inflammatory cytokine (IL-10) production in lungs and serum. These results were consistent with the data observed in S. aureus-infected bone marrow-derived macrophages (BMDMs). All these results suggested that during S. aureus infection, TLR2, TLR4, and NLRP3 has time-dependent effect in regulating the balance between immune-driven resistance and tolerance.

Codonopsis pilosula polysaccharides attenuate Escherichia coli-induced acute lung injury in mice.

Acute lung injury (ALI) is an inflammatory lung disease that is caused by bacterial infection. Lipopolysaccharide (LPS), a prototype pathogen-associated molecular pattern (PAMP) from Gram-negative bacteria such as Escherichia coli (E. coli), is an essential risk factor for ALI. LPS and E. coli induced the activation of mitogen-activated protein kinase (MAPK) and nuclear factor kappaB (NF-κB) signaling pathways, which led to the increasing immune molecule transcription, including pro-inflammatory cytokine and chemokine secretion. Codonopsis pilosula polysaccharides (CPPS) exhibit various biological activities and pharmacological effects. However, the effect of CPPS on ALI caused by LPS stimulation or E. coli infection remains unclear. Our results showed that CPPS (6.25, 12.5, 25, or 50 µg mL-1) could attenuate the secretion of TNF-α and IL-1ß and impair the phosphorylation of ERK, p38 and p65 in E. coli-infected macrophages without causing toxic reactions. In addition to regulating the secretion of pro-inflammatory cytokines and the activation of MAPK and NF-κB signaling pathways, CPPS could enhance bacterial phagocytosis and intracellular killing in macrophages, and inhibit the bacterial growth of E. coli. In vivo experiments showed that CPPS attenuated LPS- and E. coli-induced lung damage in mice, which was characterized by decreased pro-inflammatory cytokine (TNF-α, IL-1ß and IL-6) and chemokine (RANTES) production and production of the biomarkers of tissue damage (HABP2 and HMGB1) in the lungs. Altogether, this study demonstrated that CPPS have a protective effect on the lungs in LPS- and E. coli-induced ALI mouse models, suggesting that CPPS could be a potential drug for the treatment of ALI.

Study on the drug resistance and pathogenicity of Escherichia coli isolated from calf diarrhea and the distribution of virulence genes and antimicrobial resistance genes.

Introduction: The unscientific and irrational use of antimicrobial drugs in dairy farms has led to the emergence of more serious drug resistance in Escherichia coli. Methods: In this study, cases of calf diarrhea in cattle farms around the Hohhot area were studied, and Escherichia coli were identified by PCR and biochemical methods, while the distribution of virulence and drug resistance genes of the isolates was analyzed. Results: The results showed that 21 strains of Escherichia coli were isolated from the diseased materials, and the isolation rate was 60%. The isolated strains belong to 15 ST types. The drug resistance levels of the isolated strains to 20 kinds of antimicrobial agent viz., penicillin, ampicillin, cefotaxime, cefepime, cefoxitin, and ceftriaxone were more than 50%. The resistance rate to meropenem was 10%. The resistance rates to tetracycline and doxycycline were 33% and 29%, to ciprofloxacin, levofloxacin and enrofloxacin were 48%, 33%, and 33%, to amikacin, kanamycin and gentamicin were 19%, 24% and 38%, to cotrimoxazole and erythromycin were 48% and 15%, to florfenicol, chloramphenicol and polymyxin B were 29%, 33%, and 5%. Nine strains of pathogenic calf diarrhea Escherichia coli were isolated by mouse pathogenicity test. The detection rates of virulence genes for the adhesion class were fimC (95%), IuxS (95%), eaeA (76%), fimA (62%), ompA (52%), and flu (24%). The detection rates for iron transporter protein like virulence genes were iroN (33%), iutA (19%), fyuA (14%), irp5 (9.5%), Iss (9.5%), and iucD (9.5%). The detection rates for toxin-like virulence genes were phoA (90%), Ecs3703 (57%), ropS (33%), hlyF (14%), and F17 (9.5%). The detection rates of tetracycline resistance genes in isolated strains were tetB (29%), tetA (19%) and tetD (14%). The detection rates for fluoroquinolone resistance genes were parC (Y305H, P333S, R355G) (9.5%), gyrA (S83L, D87N) (28%), qnrD (43%), and qnrS (9.5%). The detection rates for ß-lactam resistance genes were bla CTX-M (29%), bla TEM (29%), and bla SHV (9.5%). The detection rates for aminoglycoside resistance genes were strA-B (57%), aacC (33%), aac(3')-IIa (29%), and aadAI (24%). The detection rates of chloramphenicol resistance genes floR and sulfa resistance genes sul2 were 24 and 33%. Conclusion: Pathogenic Escherichia coli causing diarrhea in calves contain abundant virulence genes and antibiotic resistance genes.

Proliferation of bovine endometrial epithelial cells is promoted by prostaglandin E2-PTGER2 signaling through cell cycle regulation.

It is known that prostaglandin E2 (PGE2) induces proliferation of epithelia in bovine endometrial explants, however, the detailed mechanism of regulation of PGE2 in inducing bovine endometrial epithelial cell (bEEC) proliferation is unclear. In this study, we determined whether proliferation of bEECs is promoted by PGE2-prostaglandin E receptor 2 (PTGER2) signaling activation through cell cycle regulation. The results demonstrated that bEECs proliferation was induced by treatment of PGE2 and PTGER2 agonist butaprost. These processes were down-regulated by PTGER2 antagonist AH6809 and CDK inhibitors (LEE011, CDK2 Inhibitor II and Ro 3306). PGE2 and butaprost induced cyclins (A, B1, D1, D3 and E2), cyclin-dependent kinases (CDKs, 1, 2, 4 and 6), and epidermal growth factor (EGF) expression were inhibited by AH6809 treatment in bEECs. Moreover, proliferating cell nuclear antigen (PCNA), cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), and PTGER2 expression in bEECs were up-regulated by PGE2 and butaprost treatment. Our data demonstrate that PGE2-PTGER2 signaling activation has a direct molecular association with cell cycle regulation and cell proliferation in bEECs. Collectively, these findings will improve our understanding of the roles for PGE2-PTGER2 signaling activation in the physiological and pharmacological processes of bovine endometrium.

Pheasant motilin, its distribution and gastrointestinal contractility-stimulating action in the pheasant.

Previously, pheasant motilin was identified as a 22-amino acid peptide with a sequence of FVPFFTQSDI QKMQEKERIK GQ. In the present study, the distribution of pheasant motilin mRNA was determined and compared with that of ghrelin, a motilin-related peptide. The effects of pheasant motilin on the cognate gastrointestinal (GI) muscle strips were also examined in an in vitro contraction study. The expression of pheasant motilin mRNA was highest in the small intestine (duodenum, jejunum and ileum), moderate in the colon and very low in the brain, lung, heart, pancreas, esophagus, proventriculus, gizzard and caecum, and this distribution was in contrast with that of ghrelin mRNA. Pheasant motilin caused contraction of the cognate GI tract in a region-dependent manner, similar to chicken motilin. The contraction in the small intestine was large and was not affected by atropine. In contrast, contraction in the proventriculus was small and was decreased by atropine. The crop and colon were insensitive to pheasant motilin. Neither GM109 nor MA2029, mammalian motilin receptor antagonists inhibited the contractions of pheasant motilin. Erythromycin was ineffective in the pheasant ileum, although it caused contraction of the rabbit duodenum. These results indicate that pheasant motilin caused contraction through an action on smooth muscles in the small intestine and an action on enteric cholinergic nerves in the proventriculus. This high responsiveness of the small intestine suggests that motilin is a regulator of small intestinal motility in avians, and the characteristic of the motilin receptor in the pheasant might be different from that in mammals, as is that in chickens.

Purification, Identification, Activity Evaluation, and Stability of Antioxidant Peptides from Alcalase Hydrolysate of Antarctic Krill (Euphausia superba) Proteins.

For utilizing the largest source of marine proteins, Antarctic krill (Euphausia superba) proteins were defatted and hydrolyzed separately using pepsin, alcalase, papain, trypsin, and netrase, and alcalase hydrolysate (EPAH) showed the highest DPPH radical (DPPH·) and hydroxyl radical (HO·) scavenging activity among five hydrolysates. Using ultrafiltration and chromatography methods, fifteen antioxidant peptides were purified from EPAH and identified as Asn-Gln-Met (NQM), Trp-Phe-Pro-Met (WFPM), Gln-Asn-Pro-Thr (QNPT), Tyr-Met-Asn-Phe (YMNF), Ser-Gly-Pro-Ala (SGPA), Ser-Leu-Pro-Tyr (SLPY), Gln-Tyr-Pro-Pro-Met-Gln-Tyr (QYPPMQY), Glu-Tyr-Glu-Ala (EYEA), Asn-Trp-Asp-Asp-Met-Arg-Ile-Val-Ala-Val (NWDDMRIVAV), Trp-Asp-Asp-Met-Glu-Arg-Leu-Val-Met-Ile (WDDMERLVMI), Asn-Trp-Asp-Asp-Met-Glu-Pro-Ser-Phe (NWD-DMEPSF), Asn-Gly-Pro-Asp-Pro-Arg-Pro-Ser-Gln-Gln (NGPDPRPSQQ), Ala-Phe-Leu-Trp-Asn (AFLWA), Asn-Val-Pro-Asp-Met (NVPDM), and Thr-Phe-Pro-Ile-Tyr-Asp-Tyr-Pro-Gln (TFPIYDPQ), respectively, using a protein sequencer and ESI/MS. Among fifteen antioxidant peptides, SLPY, QYPPMQY and EYEA showed the highest scavenging activities on DPPH· (EC50 values of 1.18 ± 0.036, 1.547 ± 0.150, and 1.372 ± 0.274 mg/mL, respectively), HO· (EC50 values of 0.826 ± 0.027, 1.022 ± 0.058, and 0.946 ± 0.011 mg/mL, respectively), and superoxide anion radical (EC50 values of 0.789 ± 0.079, 0.913 ± 0.007, and 0.793 ± 0.056 mg/mL, respectively). Moreover, SLPY, QYPPMQY and EYEA showed strong reducing power, protective capability against H2O2-damaged plasmid DNA, and lipid peroxidation inhibition ability. Furthermore, SLPY, QYPPMQY, and EYEA had high stability under temperatures lower than 80 °C, pH values ranged from 6-8, and simulated GI digestion for 180 min. The results showed that fifteen antioxidant peptides from alcalase hydrolysate of Antarctic krill proteins, especially SLPY, QYPPMQY and EYEA, might serve as effective antioxidant agents applied in food and health products.

Indicator Compounds Representative of Contaminants of Emerging Concern (CECs) Found in the Water Cycle in the United States.

The presence of contaminants of emerging concern (CECs) in the aquatic environment has recently become a global issue. The very large number of CECs reported in the literature makes it difficult to interpret potential risks as well as the removal efficiencies, especially for the more recalcitrant compounds. As such, there is a need for indicator compounds that are representative of CECs detected in systems worldwide. In an effort to develop such a list, five criteria were used to address the potential for applying indicator compounds; these criteria include usage, occurrence, resistance to treatment, persistence, and physicochemical properties that shed light on the potential degradability of a class of compounds. Additional constraints applied included the feasibility of procuring and analyzing compounds. In total, 22 CECs belonging to 13 groups were selected as indicator compounds. These compounds include acetaminophen and ibuprofen (analgesic); erythromycin, sulfamethoxazole, and trimethoprim (antibiotics); diazepam and fluoxetine (antidepressants); carbamazepine (antiepileptic); atenolol and propranolol (ß-blockers); gemfibrozil (blood lipid regulator); tris(2-chloroethyl)phosphate (TCEP) (fire retardant); cotinine (nicotine metabolite); atrazine, metolachlor, and N,N-diethyl-meta-toluamide (DEET) (pesticides); 17ß-estradiol and cholesterol (steroids); caffeine (psychomotor stimulant); perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) (surfactants); and iopromide (X-ray contrast agent). These thirteen groups of compounds represent CECs with the greatest resistance to treatment processes, most persistent in surface waters, and detected with significant frequency throughout the water cycle. Among the important implications of using indicator compounds are the ability to better understand the efficacy of treatment processes as well as the transport and fate of these compounds in the environment.