Sulpholipid formation in rat submandibular gland

Impaired Ratio of Unsaturated to Saturated Non-Esterified Fatty Acids in Saliva from Patients with Cystic Fibrosis

Impaired salivary non-esterified fatty acids (NEFA) levels have been previously observed in cystic fibrosis (CF). This study aimed to characterize the salivary NEFA profile in CF and to examine whether the alterations are related to the pancreatic status and/or lung disease severity. We analyzed salivary NEFA, cholesterol and interleukin-6 (IL-6) in CF patients (n = 66) and healthy subjects (n = 48). CF patients showed higher salivary levels of cholesterol, total NEFA (that was negatively correlated with serum triglycerides), unsaturated NEFA/saturated NEFA (U/S NEFA) ratio and IL-6 than controls. The U/S NEFA ratio was positively correlated with IL-6 in both patients and controls, suggesting an association between this parameter and local inflammation independently from the disease. No correlation between salivary lipids and pancreatic status was observed, while the U/S NEFA ratio was higher in patients with severe lung disease than mild/moderate severity and may represent a prognostic marker of lung disease in CF.

Enzymatic sulfation of triglucosyl monoalkylmonoacylglycerol in rat salivary glands

A sulfotransferase activity present in the cytosol fraction of rat submandibular and parotid salivary glands catalyzes the transfer of sulfate group from 3'-phosphoadenosine-5'-phosphosulfate to C-6 of the terminal glucose residue of Glc alpha 1 leads to 6Glc alpha 1 leads to 6Glc alpha 1 leads to 3-1, (3)-0-alkyl-2-0-acylglycerol to form sulfated triglucosyl glyceroglucolipid. The reaction proceeds at its optimum at pH 7.8, and requires the detergent Triton X-100, F1- and Mg2+. The enzyme does not catalyze the sulfation of glycosphingolipids. The apparent Km of the submandibular enzyme for triglucosyl glyceroglucolipid is 78.4 microM, and that of parotid, 58.8 microM. Analysis of the permethylated 35S-labeled enzymatic product demonstrated that the sulfate group is located at C-6 of the terminal glucose residue.

In-vitro biosynthesis of sulphatoglycosphingolipids by rat submandibular salivary glands

A sulphotransferase activity, concentrated mainly in the microsomal fraction, which catalyses the transfer of sulphate group from 3'-phosphoadenosine-5'-phosphosulphate to galactosylceramide and lactosylceramide was demonstrated in rat submandibular and sublingual glands. However, the sulphotransferase activity of this fraction in submandibular glands was about ten times higher than in sublingual glands. Optimum enzyme activity was obtained using the detergent Triton X-100, F-, and Mg2+ at a pH of 6.8. The enzyme did not catalyse the transfer of sulphate to glucosylceramide, trihexosylceramide and triglucosyl glyceroglucolipid. The sulphotransferase exhibited similar affinity for both galactosyl- and lactosylceramide. The apparent Km of the enzyme for galactosylceramide was 3.8 X 10(-5) M, and for lactosylceramide, 4.3 X 10(-5) M. The results of compositional analysis and periodate-oxidation studies of the 35S-labelled products of the enzyme reactions established that in both [35S]-sulphatoglycosphingolipids the sulphate-ester group is located at C-3 of the galactose residue.

Lipid composition of human parotid and submandibular saliva from caries-resistant and caries-susceptible adults

The lipid content and composition of parotid and submandibular saliva from caries-resistant (DMFS of 0) and caries-susceptible (DMFS greater than 15) adults was investigated. Lipids were extracted from dialysed and lyophilized saliva, collected from 10 subjects in each group, and fractionated into neutral lipids, glycolipids and phospholipids. The lipids in each fraction were separated into individual components by thin-layer chromatography and quantitated. The parotid and submandibular saliva of caries-resistant subjects contained 37 and 35 per cent fewer lipids/100 ml of saliva than that of the caries-susceptible group, and had less (p less than 0.001) neutral lipids and phospholipids. The neutral lipids of caries-resistant saliva contained (mg/100 ml of saliva) considerably (p less than 0.001) fewer free fatty acids, triglycerides and cholesterol esters. The glycolipids consisted exclusively of glyceroglucolipids and their content was similar in both groups. The content of phospholipids in the salivas of the caries-resistant was 25 and 33 per cent lower than that of the caries-susceptible. The data suggest a relationship between the level of lipids in salivary secretions and resistance to caries.

Cerebroside sulfotransferase in rat gastric mucosa

1. Cerebroside sulfotransferase activity was demonstrated in rat gastric mucosa. This enzyme preparation catalyzes the transfer of sulfate group from 3'-phosphoadenosine-5'-phosphosulfate to added cerebroside and lactosylceramide. 2. Psychosine also serves as an acceptor for sulfate group. 3. Both hydroxy-fatty acid and non-hydroxy-fatty acid containing cerebrosides are equally sulfated. However, this enzyme is inactive toward glucosylceramide. 4. The optimum pH is around 6.0. The reaction is stimulated by the addition of 0.4-0.9% of Triton X-100. 5. The presence of 2-4 mM ATP moderately stimulates the reaction, but is inhibitory when the concentration exceeds 6 mM. 6. EDTA has no effect. 7. Both Mg2+ and Ca2+ stimulate at lower concentrations (less than 16 mM), but inhibit at higher concentrations (greater than 20 mM). Mn2+, however, is a strong inhibitor even at 8 mM concentration. 8. The apparent Km for cerebroside is 0.04 mM, while that for 3'-phosphoadenosine-5'-phosphosulfate is 0.45 microM.