Mucus subunits

V. cholerae is a gram-negative bacillus. Vibrios pass through the stomach to colonize the upper small intestine. Vibrios have filamentous protein extensions that attach to receptors on the intestinal mucosa, and their motility assists with penetration of the mucus layer.2 The cholera enterotoxin consists of two subunits, one of which (subunit A) is transported into the cells and causes an increase in cyclic AMP, which leads to a deluge of fluid into the small intestine.20 This large volume of fluid results in the watery diarrhea that is characteristic of cholera. The stools are an electrolyte-rich isotonic fluid, the loss of which results in blood volume depletion followed by low blood pressure and shock.2 Of note, the diarrheal fluid is highly infectious. 

Fig. 3.3. Schematic illustration of the proposed architecture of mucus glycoproteins, (a) Subunits constitute a linear array of oligosaccharide clusters interspersed with naked stretches of protein. (b) Trypsin digestion affords glycopeptides corresponding to the oligosaccharide clusters. (c) The whole mucins are formed by an end-to-end association of subunits via disulphide bonds, (d) The hydrodynamic model of mucus glycoproteins conforms to a random coil within a spheroidal solvent domain. (After Allen et al., 1984.)...

MNNG A-methyl-A -nitro-TV-nitrosoguanidine. monomer single subunit of a compound such as a protein, monomorphic with one form, mucosa mucus membrane. 

The cystic fibrosis transmembrane conductance regulator (CFTR) was named for its role in cystic fibrosis. A mutation in the gene encoding its transmembrane subunits results in dried mucus accumulation in the airways and pancreatic ducts. 

Figure 3-4. Adrian Allen s "Bottle Brush" structure for each of the four subunits of hog gastric mucus. This figure is from a late publication, but an essentially similar one was shown and published before 1975. (From Allen A, The structure and function of gastrointestinal mucus, in Harmon JW, ed Basic Mechanisms of Gastrointestinal Mucosal Cell Injury and Protection. Baltimore Williams Wilkins, 1981, pp 351-365. Copyright 1981 reproduced by permission.)...

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