D mannose

Polygonatum sibiricum was collected from Baiyun Mountain, Luoyang City, Henan Province, China. P. kingianum was collected from Mile Mountain, Mile City, Yunnan Province, China. P. cyrtonema was collected from Longcanggou, Yingjing County, Yaan City, Sichuan Province, China. It was identified as Polygonatum sibiricum by Dr. Lixia Li, College of Veterinary Medicine, Sichuan Agricultural University. The rhizomes of all materials were washed, sliced, steamed for 60 mins, and then dried at 50°C.
Standard acetic acid, propionic acid, and butyric acid were purchased from Sigma-Aldrich. EMB medium, MRS medium, and BS medium were obtained from Hope Bio Biotechnology Co., Ltd. (Qingdao, China). H&E and AB-PAS stain kits were purchased from Solarbio (Beijing, China). RevertAid First Strand cDNA was purchased from Thermo Fisher Scientific. SYBR Green Supermix was purchased from Bio-Rad.
The standards of D-Mannose (Man); L-Rhamnose (Rha); D-Glucuronic acid (GlcA); D-Galactose (Gal); D-Glucose (Glc); D-Galacturonic acid (GalA); D-Fucose (Fuc); D-Xylose (Xyl); L-Arabinose (Ara); and D-Fructose (Fru) were purchased from Solarbio (Beijing, China). All other chemicals, such as phenol, sulfuric acid, trichloromethane, isopropyl alcohol, ethanal, etc., were all of analytical grade and obtained from the Kelong Chemical factory (Chengdu, China).

A549 cells seeded in 96-well plates were incubated with the K. pneumoniae strains, supernatants, inosine (Abmole Bioscience Inc., Houston, TX, USA), or D-mannose (Solarbio, Beijing, China). Then, CCK-8 was used to detect the cell viability at OD 450 with a microplate reader (BioTek Gen5; BioTek Instruments, Winooski, VT, USA), according to the instructions of Cell Counting kit-8 (M4839, 500 test/5 mL, Abmole Bioscience Inc., Houston, TX, USA).

A549 cells were seeded in 96-well plates at 5000 cells per well. After 24 h, the A549 cells were separately treated with 1–8 mM inosine (Abmole Bioscience Inc., Houston, TX, USA) diluted in PBS. inosine was inhibited by a 30 min pre-treatment of the A_2AR antagonist ZM241385 (Abmole Bioscience Inc., Houston, TX, USA) at a concentration of 10 nM. D-Mannose (Solarbio, Beijing, China) was diluted in the cell medium at a concentration of 0.1–10 mM. For strain supernatant stimulation, A549 cells were treated by addition of 10, 20, 30 μL of supernatants to the medium, with or without the Kp-S (MOI 1).