Urea

AGS cells were cultured in two 12 well plates and incubated with lactobacilli (MOI = 100) and H. pylori P12-GFP (MOI = 100) for 6h. At the end of incubation, one plate of the cells was washed thrice with PBS and photographed by fluorescence and white light. A Urease detection reagent was prepared by adding concentrated hydrochloric acid into the PBS (pH=7.4) to adjust the solution to pH=6.8. Urea (Solarbio) and phenol red (Solarbio) were weighed and added to reach concentrations of 110mmol/L and 10mg/L, respectively, and then dissolved by vigorously shaking. To the other 12well plates, 1 ml Urease detection reagent was added. After 1-7 hours of reaction, 80μl medium was withdrawn to record the absorbance value at 540nm(Shmuely et al., 2004 (link); Rokka et al., 2008 (link); Tharmalingam et al., 2014 (link); Yang et al., 2020 (link)).

Zearalenone (ZEN), α-zearalenol (α-ZOL), and β-zearalenol (β-ZOL) standards were purchased from Sigma-Aldrich (St. Louis, MO, USA) and stored at −20 °C. Stock solutions of ZEN (1 mg/L), α-ZOL (1 mg/L), and β-ZOL (1 mg/L) were prepared by dissolving them in 100% methanol. The standard solutions for high-performance liquid chromatography (HPLC) calibration were prepared by diluting the stock solution with a methanol/water (50/50, v/v) mixture. Other chemicals such as urea, sodium dodecyl sulfate (SDS), m-periodate, ploymyxin B, protease E, and lipase were purchased from Solarbio Science & Technology Co., Ltd. (Beijing, China). The Lactobacillus biochemical identification Kit and De Man Rogosa and Sharpe (MRS) medium were provided by Huankai Microbial Science & Technology Co., Ltd. (Guangzhou, China). All the other chemicals used in this experiment were of chromatographic or analytical grade.

Pro and Pep were purchased from the Nutrily Biotechnology, Ltd. (Anyang, Henan, China). Lactobacillus acidophilus JCM 1132 was purchased from the China General Microbiological Culture Collection Center (Beijing, China). Pepsin and trypsin were purchased from the Novozymes (Beijing, China). Bicinchoninic acid (BCA) protein assay kit, acrylamide, glycine, sodium dodecyl sulfate (SDS), Tris, urea and loading buffer were purchased from Solarbio (Beijing, China). Ammonium persulfate and tetramethylethylenediamine (TEMED) were purchased from Amersco (Framingham, USA). Coomassie Brilliant Blue R-250 was purchased from Bio-Rad (Richmond, CA, USA). MRS broth and MRS agar were purchased from Aobox Biotechnology, Ltd. (Beijing, China). Bis trifluoroacetamide (BSTFA), fatty acid methyl ester (FAME), methoxy amination hydrochloride, trimethyl chlorosilane (TMCS), standards of lactic acid, acetic acid, glycine, Gly-Gly-Gly, bacitracin and insulin were purchased from Sigma-Aldrich (St. Louis, MO, USA). 2-Chloro-l-phenylalanine was purchased from Hengbai Biological Technology, Ltd. (Shanghai, China). High performance liquid chromatography (HPLC) grades of acetonitrile, methanol, chloroform, pyridine and trifluoroacetic acid (TFA) were purchased from Fisher Scientific (Ottawa, ON, Canada).

SPI (92% protein) for the preparation of peptides was purchased from Shandong Yuxin Bio-Tech Co., Ltd. (Shandong, China). Neutral and alkaline proteases used for enzymolysis of the SPI were provided by Novozymes (Beijing, China). Rainbow pre-stained protein marker (11–180 kDa) was purchased from Genview (Glenview, USA); Laemmli sample buffer was purchased from Bio-Rad (Hercules, USA); Tris-glycine-SDS, 30% Acrylamide/Bis solution, and urea were purchased from Solarbio (Beijing, China); and ammonium persulfate, β-mercaptoethanol, and tetramethylethylenediamine (TEMED) were purchased from Ameresco (Framingham, USA). Pentobarbital Sodium was purchased from Aikon Biomedicine Co., Ltd. (Jiangsu, China). Rat IgM, IgG, IgA, IL-1β, TNF-α, and RANTES ELISA quantification kits were purchased from Myhalic Biotechnology Co., Ltd (Catalog number: RA20444 for IgM, RA20096 for IgG, RA20442 for IgA, RA20020 for IL-1β, RA20035 for TNF-α, RA20511 for RANTES, Bioswamp, Wuhan, China).