Choline-phosphate cytidyltransferase activity and phosphatidylcholine synthesis in rat granular pneumocytes are increased with exogenous fatty acids

We investigated the effect of exogenous fatty acids on phosphatidylcholine (PC) and disaturated phosphatidylcholine (DSPC) synthesis by rat granular pneumocytes in primary culture. Synthesis of PC and DSPC from [3H-methyl]choline, as evaluated by increasing specific activity (pmol choline incorporated/microgram phosphorus), was linear for 3 h. Exogenous palmitic, oleic, linoleic, or linolenic acid (100 microM each) increased the synthesis of PC by approx. 50% during incubation for 3 h. In contrast, synthesis of DSPC was increased only by palmitic acid. The increase in DSPC synthesis was approx. 150% after 3 h. Conversion of choline phosphate to PC was increased in the presence of palmitic or oleic acid as indicated by pulse-chase studies with [3H-methyl]choline in the intact cells. Cells incubated for 3 h with either oleic or palmitic acid showed increased choline-phosphate cytidyltransferase activity in the cells and the microsomal fraction. In addition, oleic acid increased the activity of this enzyme in the cytosolic fraction. The distribution of this enzyme in cytosolic and microsomal fraction was 24 and 76% in the cells incubated with palmitic acid and 32 and 68% in control cells. These results suggest that exogenous fatty acids stimulate the de novo pathway of PC synthesis in granular pneumocytes by increasing the microsomal choline-phosphate cytidyltransferase activity.     

Molecular link between dietary fibre,gut microbiota and health

Molecular Biology Reports - Natural polysaccharides cellulose, hemicelluloses, inulin etc., galactooligosaccharides (GOS), and fructooligosaccharides (FOS) play a significant role in the...     

Lipase activity of Lactobacillus brevis

Summary The intracellular lipase from a strain of Lactobacillus brevis was partially purified and properties of the enzyme studied. Of the simple triglycerides, tripropionin was hydrolysed most easily by the enzyme as compared to others such as tributyrin, tricaproin and tricaprylin. Of the natural triglycerides such as butter oil and coconut oil, the former was degraded more readily than the latter. Among unsaturated triglycerides, the enzyme preferentially hydrolysed triolein as compared to olive oil. Highest enzymatic activity was observed at 30° C after 3.5 h incubation at pH 6.5. Salts of manganese, magnesium, sodium and calcium stimulated lipase activity while silver, mercury and Zinc were inhibitory. The enzyme was completely inactivated at 62.8° C after 30 min and at 71.7° C after 16 sec.     

Effect of acute hypobaric hypoxia on 32-P incorporation into phospholipids of alveolar surfactant, lung, liver and plasma of rat.

Exposure of adult rats to hypobaric hypoxia caused hypolipidemia, hypotriglyceridemia and hypophospholipidemia. Hypobaric hypoxia produced an increase in liver triglyceride and cholesterol levels and a decrease in lung triglyceride, total phospholipid and phosphatidyl choline. The proportion of phosphatidyl choline in the pulmonary surfactant fraction I phospholipids (responsible for reducing surface tension) decreased (55.2% as compared to 80.4% in control animals). Incorporation of 32-P into liver phosphatidyl ethanolamine was significantly increased, incorporation into lung phosphatidyl choline and phosphatidyl ethanolamine was increased whereas a decreased incorporation into plasma phosphatidyl choline was observed. The data suggest an enhanced lipid synthesis in liver with a probable impairment of mobilization into plasma.     

Common protozoans as an uncommon cause of respiratory ailments in HIV-associated immunodeficiency

Opportunistic infections (OIs) are the leading cause of mortality and morbidity among HIV-positive subjects. The breadth of reports of the rare occurrence of OIs in HIV/AIDS has been increasing over the years and more recent studies have outlined the changing trends in the emergence of newer pathogens. Recent reports of the association of certain protozoans that normally do not infect sites other than their normal sites of localization have generated huge interest among scientists. The complete depression of the immune system, followed by the onset of OIs, especially due to protozoans, i.e. toxoplasmosis, isosporiasis, leishmaniasis, cyclosporosis, microsporidiosis and cryptosporidiosis, is not uncommon in AIDS. The immunologic and pathologic basis behind the susceptibility of immunodepressed individuals to these 'non-site-specific parasites' is likely to have a huge impact on HIV disease progression. Certain possible shortcomings in the immunologic armory of immunodeficient subjects, their failure to contain the establishment of these 'uncommon' agents in the human host and their significance in HIV disease progression are discussed.