scholarly journals THE LACTASE ACTIVITY OF THE INTESTINAL MUCOSA OF THE DOG AND SOME CHARACTERISTICS OF INTESTINAL LACTASE

1935 ◽  
Vol 109 (1) ◽  
pp. 159-168
Author(s):  
F.A. Cajori
Keyword(s):  
Intestinal Mucosa ◽  
Lactase Activity

Essential fatty acid deficiency in mice impairs lactose digestion

2008 ◽  
Vol 295 (3) ◽  
pp. G605-G613 ◽  
Author(s):  
S. Lukovac ◽  
E. L. Los ◽  
F. Stellaard ◽  
E. H. H. M. Rings ◽  
H. J. Verkade
Keyword(s):  
Small Intestine ◽  
Fatty Acid ◽  
Mrna Expression ◽  
Essential Fatty Acid ◽  
Intestinal Mucosa ◽  
Intestinal Morphology ◽  
Lactase Activity ◽  
Intestinal Histology ◽  
Fat Malabsorption ◽  
Small Intestinal

Essential fatty acid (EFA) deficiency in mice induces fat malabsorption. We previously reported indications that the underlying mechanism is located at the level of the intestinal mucosa. We have investigated the effects of EFA deficiency on small intestinal morphology and function. Mice were fed an EFA-deficient or control diet for 8 wk. A 72-h fat balance, the EFA status, and small intestinal histology were determined. Carbohydrate absorptive and digestive capacities were assessed by stable isotope methodology after administration of [U-13C]glucose and [1-13C]lactose. The mRNA expression and enzyme activity of lactase, and concentrations of the EFA linoleic acid (LA) were measured in small intestinal mucosa. Mice fed the EFA-deficient diet were markedly EFA-deficient with a profound fat malabsorption. EFA deficiency did not affect the histology or proliferative capacity of the small intestine. Blood [13C6]glucose appearance and disappearance were similar in both groups, indicating unaffected monosaccharide absorption. In contrast, blood appearance of [13C]glucose, originating from [1-13C]lactose, was delayed in EFA-deficient mice. EFA deficiency profoundly reduced lactase activity (−58%, P < 0.01) and mRNA expression (−55%, P < 0.01) in mid-small intestine. Both lactase activity and its mRNA expression strongly correlated with mucosal LA concentrations ( r = 0.77 and 0.79, respectively, P < 0.01). EFA deficiency in mice inhibits the capacity to digest lactose but does not affect small intestinal histology. These data underscore the observation that EFA deficiency functionally impairs the small intestine, which in part may be mediated by low LA levels in the enterocytes.

scholarly journals Human small-intestinal β-galactosidases. Separation and characterization of one lactase and one hetero β-galactosidase

1969 ◽  
Vol 114 (2) ◽  
pp. 351-359 ◽  
Author(s):  
Nils-Georg Asp ◽  
Arne Dahlqvist ◽  
Otakar Koldovský
Keyword(s):  
Intestinal Mucosa ◽  
Gel Filtration ◽  
Competitive Inhibitor ◽  
The Other ◽  
Artificial Substrates ◽  
Small Intestinal Mucosa ◽  
Lactase Activity ◽  
Ph Optimum ◽  
Small Intestinal

1. Two β-galactosidases from human small-intestinal mucosa were separated by gel-filtration chromatography and the properties of the two enzymes were studied. Lactose and four hetero β-galactosides were used as substrates. 2. One of the enzymes was particle-bound and could be partially solubilized with papain. Of the substrates hydrolysed by this enzyme, lactose was hydrolysed most rapidly. This enzyme is thus essentially a disaccharidase and is named lactase. It is presumably identical with the ‘lactase 1’ described earlier. 3. The other enzyme was mainly soluble and hydrolysed all artificial substrates used, whereas no lactase activity could be detected. This enzyme has therefore been designated hetero β-galactosidase. 4. p-Chloromercuribenzoate (0·1mm) inhibited the hetero β-galactosidase completely but did not influence the activity of the lactase. Tris was a competitive inhibitor of both enzymes. 5. The residual lactase activity in the mucosa of lactose-intolerant patients may be exerted by a small amount of remaining lactase as such, or possibly by a third enzyme with a more acid pH optimum.

scholarly journals Carbohydrase activities in the bovine digestive tract

1968 ◽  
Vol 108 (5) ◽  
pp. 839-844 ◽  
Author(s):  
R. C. Siddons
Keyword(s):  
Small Intestine ◽  
Digestive Tract ◽  
Intestinal Mucosa ◽  
Distal Part ◽  
Amylase Activity ◽  
Proximal Part ◽  
Lactase Activity ◽  
Uniform Pattern ◽  
Maltase Activity ◽  
Intestinal Sucrase

1. The carbohydrase activities of homogenates of mucosa from the abomasum, small intestine, caecum and colon, and of the pancreas of cattle were studied. 2. The disaccharidase activities were located mainly in the small intestine and showed a non-uniform pattern of distribution along the small intestine; trehalase activity was highest in the proximal part, lactase and cellobiase activities were highest in the proximal and middle parts and maltase activity was highest in the distal part. 3. The intestinal lactase and cellobiase activities were highest in the young calf and decreased with age, whereas the intestinal maltase and trehalase activities, which were very low compared with the lactase activity, did not change with age. 4. No intestinal sucrase or palatinase activity was detected in the calf or in the adult cow. 5. Homogenates of intestinal mucosa also exhibited amylase and dextranase activity. 6. Homogenates of the pancreas possessed a strong amylase activity and a weak maltase activity. The maltase activity did not change with age, whereas the amylase activity increased with age. 7. No marked differences were observed between the carbohydrase activities of calves fed solely on milk and those of calves given a concentrate–hay diet from 6 weeks of age.

scholarly journals Human small-intestinal β-galactosidases. Separation and characterization of three forms of an acid β-galactosidase

1971 ◽  
Vol 121 (2) ◽  
pp. 299-308 ◽  
Author(s):  
Nils-Georg Asp
Keyword(s):  
Intestinal Mucosa ◽  
Total Activity ◽  
Small Intestinal Mucosa ◽  
Lactase Activity ◽  
Considerable Part ◽  
Ph Optimum ◽  
Rate Of Hydrolysis ◽  
Small Intestinal ◽  
Hydrolysis Of

1. An acid β-galactosidase, optimum pH4.0–4.5, in the human small-intestinal mucosa was separated and characterized. 2. Autolysis of mucosal homogenates at acid pH inactivated the lactase and hetero β-galactosidase; the total activity of the acid β-galactosidase was only slightly depleted, but a greater proportion of the enzyme was solubilized by this treatment. 3. Separation on a Sephadex G-200 column revealed that the acid β-galactosidase could occur in at least three different forms, probably representing monomer, dimer and octamer or polymer of the enzyme. 4. The properties of the different forms of the acid β-galactosidase were studied with regard to pH optimum, Km, rate of hydrolysis of different substrates, and sensitivity to p-chloromercuribenzoate and tris as inhibitors. All these properties were the same for the different forms of the enzyme. 5. The acid β-galactosidase hydrolyses lactose as well as hetero β-galactosides and contributes to the lactase activity of intestinal biopsies also when measured at pH 6. This enzyme may therefore be responsible for a considerable part of the residual lactase activity found in lactose-intolerant patients.

Activation of isolated heterophils from chicks stimulated in vivo with salmonella enteritidis-immune lymphokines

1996 ◽  
Vol 54 ◽  
pp. 760-761
Author(s):  
R. B. Moyes ◽  
R. E. Droleskey ◽  
M. H. Kogut ◽  
J. R. DeLoach
Keyword(s):  
Lamina Propria ◽  
Intestinal Mucosa ◽  
Salmonella Enteritidis ◽  
Intestinal Tract ◽  
Polymorphonuclear Cells ◽  
Subclinical Infection ◽  
Egg Products ◽  
Immune Lymphokines ◽  
Organ Invasion

Salmonella enteritidis (SE) is of great concern to the poultry industry due to the organism's ability to penetrate the intestinal mucosa of the laying hen and subsequently colonize the ovaries and yolk membrane. The resultant subclinical infection can lead to SE infection of raw eggs and egg products. Interference with the ability of the organism to invade has been linked to the activation and recruitment of inflammatory polymorphonuclear cells, heterophils, to the lamina propria of the intestinal tract.Recently it has been established that heterophil activation and increased resistance to SE organ invasion can be accomplished by the administration of SE-immune lymphokines (SE-ILK) obtained from supernatants of concanavalin-A stimulated SE immune T lymphocytes from SE hyperimmunized hens. Invasion of SE into the lamina propria provides a secondary signal for directing activated heterophils to the site of SE invasion.

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