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Peripheral Mechanisms of Mammalian Sweet Taste
Published in Robert H. Cagan, Neural Mechanisms in Taste, 2020
William Jakinovich, Dorothy Sugarman
In a structure-activity study using the gerbils’s whole nerve response, Jakinovich9 found that turanose and palatinose, two disaccharides which closely resemble sucrose, are not as potent stimuli as sucrose (Figure 1, Table 2). Even though these two compounds contain the same monosaccharides as sucrose (glucose and fructose) with alpha glycosidic linkages, the linkage carbons of the fructose molecules are different, thus allowing the fructose moiety to mutarotate. Among the glucopyranosides tested, those with the alpha linkage, such as maltose and maltitol, are more potent stimuli than those with the beta linkage, such as cellobiose and cellobiitol. On the other hand, galactopyranosides with the beta linkage, such as lactose and lactitol, are more potent to the gerbil than melibiose and melibiitol, which contain the alpha linkage. In human psychophysical investigations, Moskowitz21 and Lee30 reported maltose to be sweeter than cellobiose and lactose to be sweeter than melibiose, suggesting that humans and gerbils have the same structure-activity requirements for these disaccharides.
Elucidating the survival and response of carbapenem resistant Klebsiella pneumoniae after exposure to imipenem at sub-lethal concentrations
Published in Pathogens and Global Health, 2018
Ye Mun Low, Chun Wie Chong, Ivan Kok Seng Yap, Lay Ching Chai, Stuart C. Clarke, Sasheela Ponnampalavanar, Kartini Abdul Jabar, Mohd Yasim Md Yusof, Cindy Shuan Ju Teh
All three CRKP strains utilized a wide range of amino acids, carbohydrates and carboxylic acids but were selective in the utilization of alcohol, amide, ester and polymer. Generally, these strains demonstrated better carbon utilization after exposure to imipenem. Carbohydrates such as 3-θ-β-D-Galactopyranosyl-D-Arabinose, D-Raffinose and stachyose were metabolized by K/1310–33 and K/1309–38 only after exposure to imipenem. It is noteworthy that K/1310–33 and K/1309–38 belonging to the same sequence type (ST), ST101 and harboring blaOXA-48 and blaKPC-2 showed varying carbon utilization. Maltitol and turanose were metabolized by K/1310–33 after imipenem treatment but these carbons were metabolized by K/1309–38 only in imipenem-free cells. After imipenem treatment, carboxylic acid metabolism for D-Malic acid and 4-Hydroxybenzoic acid were disrupted in K/1310–33 while amino acid utilization (L-Arginine, Hydroxyl-L-Proline, L-Phenylalanine) ceased in K/1309–38. In contrast, K/1309–39, a ST147 strain which harbored blaNDM-1 and blaIMP-8 exhibited similar carbon utilization regardless of the presence or absence of imipenem treatment (with the exception of palatinose, D-raffinose and β-hydroxybutryric acid) but did not utilize fatty acids (Tween 20, Tween 40, Tween 80) unlike K/1310–33 and K/1309–38 (Supplementary Table 1).
Ginsenosides Rd monomer inhibits proinflammatory cytokines production and alleviates DSS-colitis by NF-κB and P38MAPK pathways in mice
Published in Immunopharmacology and Immunotoxicology, 2022
Bo Qu, Ting Cao, Miao Wang, Shuang Wang, Wanying Li, Hui Li
Over the past decades, a variety of animal models of IBD have not only provided indispensable insights into the histopathological and morphologic changes of IBD but also played an important role in evaluating various treatment options. DSS-induced colitis is the most widely used experimental model and can rapidly cause epithelial damage in animals by orally administering DSS in their daily drinking water. Besides, DSS colitis is superior in reproducibility, availability, practicality, and cost-effectiveness to other chemical-induced experimental animal models [20]. Moreover, DSS-induced colitis models are suitable and advantaged to investigate the mechanisms of epithelial integrity or membrane permeability, mucus composition, and innate immune response in various stages of UC [21]. It is an ideal model to study the role of macrophages in the inflammatory process. Furthermore, the DSS-colitis model is a valuable tool to survey the effects of natural products as well as anti-inflammatory agents. Jia et al. [22] reported that curcumin combined with fish oil could inhibit NF-κB activation in DSS-induced colitis. Brückner et al. [23] and Bitzer et al. [24] noted polyphenol epigallocatechin-3-gallate in green tea has antioxidative activity and is a promising therapeutic extract for shorting colonic length, decreasing bloody diarrhea, and alleviating intestinal inflammation of DSS mice. In addition, many natural productions, including palmatine, krill oil-incorporated liposomes, turanose, daucosterol, peanut shell extract, aqueous extract of inonotus obliquus, compound sophorae decoction, rape bee pollen extract, and dried apple peel powder, have exhibited their effect to inhibit cytokines and enzymes, regulate the intestinal microbiota, moderate the immune responses, and alleviated colitis in DSS models [21]. Generally, DSS induced model is a mature and appropriate tool to perform colitis inflammation researches. In our study, we successfully established a mouse model of DSS-induced colitis and used it as an estimation tool to examine the efficacy of GRd. We found GRd also reduces the severity of DSS-induced colitis. Taken together, although the lack of efficacy data in human patients, various natural products have shown their function and effectiveness in the prevention or treatment of UC in DSS colitis.