ABSTRACT
Sorbin is a newly isolated intestinal peptide that has been purified because of its ability to induce water absorption. The effects that sorbin and some synthetic peptides corresponding to its C-terminal sequence have on duodenal absorption of water, chloride, and sodium were studied in comparison with the effects of vasoactive intestinal peptide (VIP), [D-Ala,Met]-enkephalinamide (DAMA), and angiotensin II. The technique of an in situ ligated duodenal loop in the rat was used for all peptides. Under the experimental conditions used, a low basal secretion of water, chloride, and sodium was obtained; VIP induced an increase of the secretion, whereas DAMA induced an absorption, both in the nanomolar dose range. Angiotensin II and sorbin induced an absorption in the picomolar dose range. The most effective doses of sorbin peptides but not of angiotensin induced the lowest final concentrations of Na+ and Cl- obtainable without inducing secondary water secretion. All synthetic peptides containing the C-terminal heptapeptide of sorbin were active in the picomolar dose range. Contrary to angiotensin, they had no effect on blood pressure.
Subject(s)
Duodenum/physiology , Intestinal Absorption/drug effects , Peptides/pharmacology , Water-Electrolyte Balance/drug effects , Amino Acid Sequence , Angiotensin II/pharmacology , Animals , Blood Pressure/drug effects , Chlorine/metabolism , Enkephalin, Methionine/analogs & derivatives , Enkephalin, Methionine/pharmacology , Male , Molecular Sequence Data , Rats , Rats, Sprague-Dawley , Sodium/metabolism , Vasoactive Intestinal Peptide/pharmacology , Water/metabolismABSTRACT
Sorbin has been isolated from extracts of porcine upper intestine, and the biological activity in absorbing water and electrolytes utilized to monitor the purification procedure. Pure sorbin was obtained in a yield of about 1 mg/Mg boiled intestine. The protein chain has 153 amino acid residues and the primary structure was determined by analyses of CNBr-cleaved fragments and four enzymatic digests. The protein has a free N-terminal Met and an amidated C-terminal Ala. No structural similarity was observed with other known proteins in data bases, but several segments have special properties and the C-terminal half is rich in Pro and Arg.
Subject(s)
Intestines/chemistry , Peptides/isolation & purification , Absorption , Amino Acid Sequence , Amino Acids/analysis , Animals , Cyanogen Bromide , Gallbladder/drug effects , Gallbladder/metabolism , Guinea Pigs , Molecular Sequence Data , Peptide Fragments/chemistry , Peptides/chemistry , Peptides/pharmacology , Swine , Water/metabolismABSTRACT
Free ceramide, glucosylceramide, and sphingomyelin were isolated from mature cells of adult rat small intestine. Free ceramide and ceramide cleaved from sphingomyelin by enzymatic hydrolysis were fractionated by thin-layer chromatography on borate-impregnated silica gel plates. Sphingoid bases were characterized by gas-liquid chromatography of aldehydes formed upon periodate oxidation. Fatty acids were quantified as methyl esters. Ceramide structures were confirmed by direct-inlet mass spectrometry. Free ceramide was found to contain two major long-chain bases in nearly equal quantity: sphingosine, mainly linked to palmitic acid, and 4D-hydroxysphinganine associated with C20 to C24 fatty acids, 22% being hydroxylated. Sphinganine occurred as a minor component linked to nonhydroxy fatty acids. Sphingomyelin contained the three long-chain bases and 63% of its ceramide was N-palmitoyl-sphingosine. Mass spectrometry of glucosylceramide confirmed 4D-hydroxyshingamine as the major sphingoid base associated preferentially with longer chain hydroxy fatty acids.
Subject(s)
Ceramides/analysis , Cerebrosides/analysis , Glucosylceramides/analysis , Intestine, Small/analysis , Sphingomyelins/analysis , Animals , Chromatography, Gas , Fatty Acids/analysis , In Vitro Techniques , Male , Mass Spectrometry , RatsABSTRACT
A Corynebacterium hydrocarboclastus culture isolated in our laboratory (see, Zajic and Knettig, Developments in Industrial Microbiology, 1971, p. 87) has been shown to produce an extracellular biopolymer with emulsifying properties when grown on a mixture of linear hydrocarbons. This microorganism was found to grow well on a variety of carbohydrates and hydrocarbons. However, the best substrates were pure linear hydrocarbons and particularly, n-C12, n-C13, and n-C14. The substrates supporting good growth gave good polymer production. Maximum cell mass of 10-11 g/liter and a maximum amount of polymer of 5-6 g/liter were recorded. The polymers recovered from the different substrates were found to be complex molecules or mixtures with a protein, a lipid, and a carbohydrate moiety. All the polymers are surface active and have two critical micelle concentrations.
Subject(s)
Corynebacterium/metabolism , Surface-Active Agents/isolation & purification , Bacterial Proteins/analysis , Carbohydrates/analysis , Emulsions , Hydrocarbons/metabolism , Lipids/analysis , Macromolecular Substances , Micelles , Polymers/isolation & purification , Structure-Activity RelationshipABSTRACT
An extracellular polymer was produced by continuous fermentation of Corynebacterium hydrocarboclastus on kerosene in a 24 liter reactor. This polymer was composed of protein, lipid, and carbohydrates. The polymer possessed surface active properties, and had two critical micelle concentrations. Its effectiveness was quite comparable to the effectiveness of synthetic surface active agents such as Tween 80 and Span 20; however, its efficiency was much lower. The polymer also had emulsifying properties. Maximum emulsification was obtained at pH 6. The emulsifying properties were unaffected by high salt concentration [up to 5% (w/v) in Na+], and tolerated a water hardness up to 5,000 ppm. A 2 hr treatment of the polymer at temperatures higher than 65 degrees C resulted in a loss of its emulsifying properties. Two microorganisms, named SLYS and Y, isolated from soil, were able to grow on the polymer as sole carbon and energy source, thus proving its biodegradability. SLYS was tentatively identified as Flavobacterium breve and Y as Flavobacterium devorans.
