Relationship between calcium and uroinic acids in the encystment of Azotobacter vinelandii.

Encystment of Azotobacter vinelandii (ATCC 12837) in modified Burk nitrogen-free medium (pH 7.0) containing 0.2 percent beta-hydroxybutyrate occurs optimally in 0.37 to 0.44 mM solutions of calcium ions. Suspension of cells in media deficient in calcium results in abortive encystment characterized by the release of viscous cyst coat material. Mature cysts rupture in ethylene glycol-bis-(beta-aminoethyl ether)-N,N'-tetraacetic acid, suggesting that calcium is a structural component of the cyst coat. Maximal stimulation of encystment by calcium ions occurs prior to the completion of the cyst exine or outer coat. The uronic acid composition of cyst components is dependent on calcium levels in the medium. Uronic acids account for 31.7 percent of the intine (inner coat) and 13 percent of the exine dry weight, and only mannuronic and guluronic acids are present in these fractions. These can be extracted as homo- and heteropolymeric sequence "blocks" characteristic of alginic acids. The polyuronic acid fraction of both the cyst coats contain approximately equal amounts of heteropolymeric (mannuronic acid/guluronic acid) blocks. The exine, however, is richer in polyguluronic acid and the intine is richer in polymannuronic acid. As a result, the mannuronic acid/guluronic acid ratio of the exine is lower than that of the intine. Slimes that form in abortive encystment are rich in polymannuronic acid and have a high mannuronic acid/guluronic acid ratio. A polymannuronic acid 5-epimerase is active in the mature cyst central body and the encystment culture fluid.     

The biosynthesis of alginic acid by Azotobacter vinelandii.

The sequence of reactions by which alginic acid is biosynthesized from sucrose in Azotobacter vinelandii was determined both by feeding radioactive individual enzymes involved. Results indicate that the first polymeric substance formed in the synthesis is polymannuronic acid and that mannuronic acid units are epimerized to guluronic acid at the polymer level. Guluronic acid does not appear to be formed at the monomer level, either free or in combination with GDP.     

P. aeruginosa SGNH Hydrolase-Like Proteins AlgJ and AlgX Have Similar Topology but Separate and Distinct Roles in Alginate Acetylation

The O-acetylation of polysaccharides is a common modification used by pathogenic organisms to protect against external forces. Pseudomonas aeruginosa secretes the anionic, O-acetylated exopolysaccharide alginate during chronic infection in the lungs of cystic fibrosis patients to form the major constituent of a protective biofilm matrix. Four proteins have been implicated in the O-acetylation of alginate, AlgIJF and AlgX. To probe the biological function of AlgJ, we determined its structure to 1.83 Å resolution. AlgJ is a SGNH hydrolase-like protein, which while structurally similar to the N-terminal domain of AlgX exhibits a distinctly different electrostatic surface potential. Consistent with other SGNH hydrolases, we identified a conserved catalytic triad composed of D190, H192 and S288 and demonstrated that AlgJ exhibits acetylesterase activity in vitro. Residues in the AlgJ signature motifs were found to form an extensive network of interactions that are critical for O-acetylation of alginate in vivo. Using two different electrospray ionization mass spectrometry (ESI-MS) assays we compared the abilities of AlgJ and AlgX to bind and acetylate alginate. Binding studies using defined length polymannuronic acid revealed that AlgJ exhibits either weak or no detectable polymer binding while AlgX binds polymannuronic acid specifically in a length-dependent manner. Additionally, AlgX was capable of utilizing the surrogate acetyl-donor 4-nitrophenyl acetate to catalyze the O-acetylation of polymannuronic acid. Our results, combined with previously published in vivo data, suggest that the annotated O-acetyltransferases AlgJ and AlgX have separate and distinct roles in O-acetylation. Our refined model for alginate acetylation places AlgX as the terminal acetlytransferase and provides a rationale for the variability in the number of proteins required for polysaccharide O-acetylation.     

Characterization of AlgMsp,an Alginate Lyase from Microbulbifer sp. 6532A

Alginate is a polysaccharide produced by certain seaweeds and bacteria that consists of mannuronic acid and guluronic acid residues. Seaweed alginate is used in food and industrial chemical processes, while the biosynthesis of bacterial alginate is associated with pathogenic Pseudomonas aeruginosa. Alginate lyases cleave this polysaccharide into short oligo-uronates and thus have the potential to be utilized for both industrial and medicinal applications. An alginate lyase gene, algMsp, from Microbulbifer sp. 6532A, was synthesized as an E.coli codon-optimized clone. The resulting 37 kDa recombinant protein, AlgMsp, was expressed, purified and characterized. The alginate lyase displayed highest activity at pH 8 and 0.2 M NaCl. Activity of the alginate lyase was greatest at 50°C; however the enzyme was not stable over time when incubated at 50°C. The alginate lyase was still highly active at 25°C and displayed little or no loss of activity after 24 hours at 25°C. The activity of AlgMsp was not dependent on the presence of divalent cations. Comparing activity of the lyase against polymannuronic acid and polyguluronic acid substrates showed a higher turnover rate for polymannuronic acid. However, AlgMSP exhibited greater catalytic efficiency with the polyguluronic acid substrate. Prolonged AlgMsp-mediated degradation of alginate produced dimer, trimer, tetramer, and pentamer oligo-uronates.     

Protuberic acid-hydrolytic enzyme in Kobayasia nipponica and characterization of the hydrolytic products

When the cold water-extract of Kobayasia nipponica containing a glycuronan, protuberic acid (PA), was allowed to stand at room temperature, PA was hydrolyzed. The optimum conditions for this PA-hydrolysis were 37 degrees C and pH 4-5 in 0.1 M acetate buffer. Characterization of the hydrolytic products was performed by chemical analysis, and by 1H- and 13C-NMR spectroscopy. They were identified as D-GlcUA and O-(alpha-L-IdUAp)-(1-4)-D-GlcUA. These results suggest that PA-hydrolytic enzyme(s) include at least endo-beta-D-glucuronidase.     

Alginate synthesis by mucoid strains of Pseudomonas aeruginosa PAO

Summary Alginic acid production by Pseudomonas aeruginosa PAO strains was studied in yeast extract/2% (w/v) gluconate medium. In all of the five strains studied, synthesis of the alginic acid was shown to occur in the stationary phase of growth. Each strain produced similar amounts of alginic acid at both 30° C and 37° C. However the amount of alginic acid varied from 7.5–11.5 gl^–1 depending upon the strain. The alginic acid was isolated, purified and its chemical composition determined. All strains produced a polysaccharide rich in polymannuronic acid which contained only polymannuronic acid blocks, polyguluronic acid blocks appeared to be absent. The amount of O-acetylation varied considerably from 2.3–14.7%. Analysis of the chain length distribution by poly-acrylamide gel electropheresis indicated that a homogeneous size of polymer was synthesised when compared to a high viscosity algal sample.     

The effects of barbiturates on the metabolism of phosphatidic acid and phosphatidylinositol in rat brain synaptosomes.

Barbiturates and diphenylhydantoin inhibit the carbamoylcholine-stimulated increase in 32P incorporation into phosphatidylinositol and phosphatidic acid, but have a relatively slight effect on the incorporation of 32P into these lipids in the absence of carbamoylcholine and no effect on 32P incorporation into phosphatidylcholine and phosphatidylethanolamine. Inhibition of the carbamoylcholine-stimulated increase was observed for pentobarbital, thiopental, phenobarbital, 5-(1,3-dimethylbutyl)-5-ethylbarbiturate, (+)- and (-)-5-ethyl-N-methyl-5-propylbarbituate and diphenylhydantoin. Similar concentrations of barbiturates and diphenylhydantoin were previously reported to inhibit the K+-stimulated Ca2+ influx, and therefore other agents that affect Ca2+ influx were tested to find whether they had any effect on 32P incorporation into these lipids. K+ (35 mM) increases 32P incorporation into phosphatidic acid, but to a smaller degree than 100 micrometer-carbamoylcholine, and its effect was inhibited by pentobarbital. Veratridine (75 micrometer) does not increase 32P incorporation into either phosphatidic acid or phosphatidylinositol, but did inhibit the carbamoylcholine-stimulated increase in 32P incorporation into phosphatidylinositol. The possible relationship between the phospholipid effect and stimulated Ca2+ influx is discussed.     

Phosphatidic acid and phosphatidylinositol labelling in adipose tissue. The role of endogenously formed adenosine.

Incorporation of [32P]Pi into phosphatidic acid and phosphatidylinositol of hamster epididymal adipocytes was partially inhibited by 3-isobutyl-1-methylxanthine. This effect of 3-isobutyl-1-methylxanthine was antagonized by isopropyl-N6-phenyladenosine but not by 2',5'-dideoxyadenosine, prostaglandin E1 or clonidine. N6-Phenylisopropyladenosine did not affect incorporation of [32P]Pi into phosphatidic acid or phosphatidylinositol when 3-isobutyl-1-methylxanthine was not present. In contrast with 3-isobutyl-1-methylxanthine inhibition of [32P]Pi incorporation into phospholipids, which was blocked only by N6-phenylisopropyladenosine, accelerated lipolysis was blocked by prostaglandin E1, clonidine and 2',5'-dideoxyadenosine as well as by N6-phenylisopropyladenosine. Phospholipid labelling was also decreased in the presence of adenosine deaminase, but not in the presence of isoprenaline (isoproterenol). The stimulatory effect of N6-phenylisopropyladenosine on [32P]Pi incorporation into phospholipids in cells exposed to 3-isobutyl-1-methylxanthine was evident as soon as 3 min after addition of the adenosine analogue and maximum 10 min after its addition. As observed by others, [32P]Pi incorporation into phospholipids was increased by the alpha 1-selective agonist methoxamine. The stimulatory effect of methoxamine occurred with a time course similar to that of N6-phenylisopropyladenosine and was present at nearly equal magnitude in the absence or presence of 3-isobutyl-1-methylxanthine. The inhibitory effects of 3-isobutyl-1-methylxanthine and adenosine deaminase on phospholipid labelling are attributed to blockade of the action, or to the enzymic removal, of adenosine formed in and released from the fat-cells during their incubation. Supporting this view is the selective reversal of the actions of 3-isobutyl-1-methylxanthine and of adenosine deaminase by N6-phenylisopropyladenosine. These findings suggest an important role for endogenous adenosine in regulation of phospholipid turnover in adipocytes.     

Studies on Inhibition of the Intestinal Absorption of Radioactive Strontium: IX. Relationship Between Biological Activity and Electron Microscopic Appearance of Alginic Acid Components

The inhibitory action of alginate on intestinal absorption of radioactive strontium was investigated in order to correlate the biological activity with the chemical composition. Alginate from Laminaria hyperborea was partially hydrolyzed with oxalic acid and the degradation products were fractionated into polymannuronic and polyguluronic acid. The activity of these products was assessed biologically in rats and morphologically by electron microscopy. Sodium polymannuronate was found to be less effective than sodium polyguluronate in preventing absorption of radiostrontium. The inhibition of absorption of radio-calcium was low and not affected by hydrolysis or fractionation. When dried from dilute aqueous solutions, the polymannuronate retained the original helical structure of alginate, while the polyguluronate showed a strong tendency to coagulate, forming granules. The variation in the biological activity was attributed to the morphological differences between these alginic acid components and it is suggested that the degree of uncoiling of the polyguluronate chain in water is greater than that of the polymannuronate chain, thus making the carboxylate ions more accessible to strontium.     

Effects of cyclic adenosine 3',5'-monophosphate on amino acid transport and incorporation into protein in the rat aorta.

To assess the effects of cyclic AMP on amino acid transport and incorporation into aortic tissue protein, rat aortic rings were incubated with the cyclic AMP analog, N6-monobutyryl cyclic AMP (MBcAMP), the phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine (MIX), and radiolabeled amino acids. Subsequently, the aortic rings were homogenized in 5% trichloroacetic acid (TCA) and processed for liquid scintillation counting. Radioactivity present in the TCA supernatant following centrifugation was used to estimate amino acid transport. TCA-precipitable radioactivity was used as a measure of amino acid incorporation into protein. MBcAMP induced an increase in the uptake of [3H]alpha-aminoisobutyric acid into aortic rings and an increase in the incorporation of radiolabeled proline and leucine into TCA-precipitable protein. Similar effects were observed with low concentrations of MIX (0.025-0.25 mM); however, at higher concentrations of MIX, there was an attenuation of the effect or frank inhibition. Maximum stimulation of transport was observed within 90-120 min of the addition of MIX or MBcAMP to the incubation medium, whereas the effect on amino acid incorporation was not detectable until after 12 h of exposure to MIX or MBcAMP. The effects of cyclic AMP on transport were observed in both the tunica media and the tunica adventitia, whereas the effects on amino acid incorporation into protein were observed only in the tunica media. These data are consistent with a possible role for cyclic AMP in promoting changes in the tunica media that could lead to the development of vascular hypertrophy.     

Studies on the inhibition of protein synthesis by selenodiglutathione.

Amino acid incorporation in a cell-free system derived from rat liver has previously been found to be inhibited by GSSeSG (selenodiglutathione). In the present experiments the effect of GSSeSG on protein synthesis in 3T3-f cells, on growth and protein synthesis in Escherichia coli, and on amino acid incorporation in a cell-free system derived from E. coli, was studied. GSSeSG inhibits the incorporation of [3H]leucine into protein by 3T3-f cells. This inhibition cannot be reversed by removing GSSeSG and is correlated with the uptake of GSSeSG. Sodium selenite (Na2SeO3) and oxidized glutathione had no inhibitory effect in this system. [3H]Uridine or [3H]thymidine incorporation into RNA or DNA was not inhibited, indicating that the primary action of GSSeSG was on protein synthesis. GSSeSG did not influence the growth of E. coli in a synthetic medium, although enhanced amino acid incorporation was observed. In the cell-free system derived from E. coli, amino acid incorporation was not changed by GSSeSG, indicating that elongation factor G, in contrast to elongation factor 2 of mammalian cell systems, is not blocked by GSSeSG.     

Studies on the biosynthesis of phenols in fungi. Conversion of [14C]orsellinic acid and [14C]orcinol into fumigatol by Aspergillus fumigatus I.M.I. 89353

1. Sodium [1-(14)C]acetate was incorporated into orsellinic acid and fumigatol by Aspergillus fumigatus. 2. [(14)C]Orsellinic acid was prepared biosynthetically. It was converted almost entirely into fumigatol and fumigatin within 2 days of supplementation of the medium. The apparent decrease in incorporation after a longer period of growth was due to decomposition of radioactive fumigatol and the production of relatively unlabelled material. The addition of orcinol to these cultures decreased the conversion of [(14)C]orsellinic acid into fumigatol. [(14)C]Orsellinic acid was incorporated into 3,4-dihydroxytoluquinol in both sets of cultures. 3. [(14)C]Orcinol was prepared from [(14)C]orsellinic acid after acid hydrolysis. It was also very effective as a precursor of fumigatol (60% incorporation). 4. The specific activity of fumigatin was lower than that of fumigatol at early stages of growth (4-5 days after inoculation) with all the labelled substrates that were tested. This indicated that fumigatin arose from fumigatol after oxidation in the medium. 5. The presence of orcinol in the medium greatly stimulated the incorporation of radioactivity (presumably derived from the (14)CO(2)H of orsellinic acid) into the isoprenoid compounds, ergosterol and ubiquinone, in the mycelium.     

The protein coats or ghosts or coliphage T2. III. Metabolic studies of Escherichia coli B infected with T2 bacteriophage ghosts

Assimilation of oxygen, inorganic phosphate, and ammonia nitrogen by normal T2 phage and T2 ghost-infected E. coli B was studied. The rate of oxygen and phosphorus uptake by ghost-infected bacteria is similar to that of normal and phage-infected cells. The R.Q. in glucose-salts medium remains approximately 1. Assimilation of ammonia nitrogen by ghost-infected bacteria is maintained at a rate approximately 80 per cent of normal. The inorganic phosphate which is assimilated was found to be incorporated into TCA-soluble compounds which were rapidly released into the medium. Within 5 minutes after absorption of the ghosts there was a loss from the cell of TCA-soluble constituents including organic phosphorus and compounds which absorb at 260 mmicro. No corresponding breakdown of nucleic acid present in the cell prior to infection could be detected. The incorporation of inorganic phosphate into organic linkages in the ghost-infected cell and its release into the medium were found to proceed at a rate approaching that of the incorporation of inorganic phosphorus into the nucleic acid of normal cells. The net increase in 260 mmicro absorbing compounds appeared to be inhibited.     

Cell surface sialoglycopeptide metabolism and surface glycosyl transferase activity in the Ehrlich ascites cell.

1. The in vivo incorporation of radioactivity from [3H]glucosamine into a trypsin labile, cell surface sialoglycopeptide fraction (SGP) of Ehrlich ascites cells was studied in the presence and absence of puromycin pretreatment. The results indicated a much more complete inhibition of incorporation into the surface SGP than in the average intracellular acid insoluble glycoproteins. No evidence of turnover of the carbohydrate portion of the surface SGP independent of protein synthesis could be obtained. 2. However, when intact cells were incubated with labelled uridine 5'-diphosphate-N-actely glucosamine or cytidine 5'-monophosphate (CMP)-sialic acid there was some incorporation largely into acid insoluble material, suggesting the presence of glycosyl transferase activity in the surface. Further evidence for surface activity was obtained when neuraminidase pretreatment of intact cells stimulated incorporation of labelled CMP-sialic acid sixfold and almost all of the incorporated counts could be released by subsequent neuraminidase treatment. Furthermore, a much greater proportion of the incorporated counts could be released by papain than by trypsin treatment of the intact cells. These results suggest that the surface acceptor for exogenously added CMP-sialic acid is not identical to the endogenously synthesized trypsin labile surface SGP.     

Sterol biosynthesis in the echinoderm Asterias rubens.

1. [2(-14)C]Mevalonic acid injected into the echinoderm Asterias rubens (Class Asteroidea) was effectively incorporated into the non-saponifiable lipid. 2. The most extensively labelled compounds were squalene and the 4,4-dimethyl sterols with much lower incorporations into the 4alpha-monomethyl and 4-demethyl sterol fractions. 3. Labelled compounds identified were squalene, lanosterol, 4,4-dimethyl-5alpha-cholesta-8,24-dien-3beta-ol and 4alpha-methyl-5alpha-cholest-7-en-3beta-ol; these are all intermediates in sterol biosynthesis. 4. The major sterol in A. rubens, 5alpha-cholest-7-en-3beta-ol, was also labelled showing that this echinoderm is capable of sterol biosynthesis de novo. 5. No evidence was obtained for the incorporation of [2(-14)C]mevalonic acid into the C28 and C29 components of the 4-demethyl sterols or 9beta,19-cyclopropane sterols found in A. rubens and it is assumed that these sterols are of dietary origin. 6. Another starfish Henricia sanguinolenta also incorporated [2(-14)C]mevalonic acid into squalene and lanosterol. 7. Various isolated tissues of A. rubens were all capable of incorporation of [2(-14)C]mevalonic acid into the nonsaponifiable lipid. With the body-wall and stomach tissues radioactivity accumulated in squalene and the 4,4-dimethyl sterols, but with the gonads and pyloric caecae there was a more efficient incorporation of radioactivity into the 4-demethyl sterols, principally 5alpha-cholest-7-en-3beta-ol.     

Amino acid analogues: uptake, pool formation and incorporation of phenylalanine and two halogenated derivatives in cultured mammalian cells.

HeLa cells take up Phe and two of its ring halogenated derivatives (pFPhe and pClPhe) with rpaidity, concentrating them against the external medium both at 4 and 37 degrees C. The majority of amino acid (greater than 90%) is accumulated without energy expenditures at 4 degrees C, and can be quickly discharged by normal cell washing procedures in saline. At 37 degrees C the freely-diffusible (FDP) pool is accompanied by another which develops more slowly and cannot diffuse out freely during washings with saline but is extractable with trichloracetic acid (the slowly-diffusible pool, SDP, or more conventionally, the acid-soluble pool). Both of the analogues produced larger pools of the latter type than Phe itself from external concentrations ranging from 10(-5) to 10(-3) M. The incorporation of pFPhe into proteins over these same concentrations ranged from 30 to 90--95% of Phe incorporation, whereas pClPhe showed negligible incorporation. From these and similar analyses it can be concluded that amino acid pools form largely independently of protein synthesis, but bear a close relationship with the external amino acid concentration. The fraction of total uptake into cellular pools entering the SDP was relatively constant over a wide range of external concentrations. pFPhe incorporation into cellular proteins produced the same labelling distribution of Phe. It appears to ener all proteins, the vast majority of which have similar half-lives and turnover rates to Phe proteins. In competition, little or no interference was experienced between the analogue and Phe in uptake and pool formation until excessive amounts of one or the other were present (50--100x). By contrast, incorporation of pFPhe into protein was markedly reduced by the presence of Phe. However, the development of normal or large pools of pFPhe or Phe in cells prior to 3H-Phe incorporation did not affect the linear incorporation pattern of the radioisotope into protein. The relationship of pools to protein synthesis is discussed, and it is concluded that, although the SDP could contain potential precursor molecules for protein synthesis, it does not usually act as the direct supplier of amino acid for protein synthesis. Alternative explanations for precursor supply are discussed.     

Correlation of Carbohydrate Catabolism and Synthesis of Macromolecules During Enzyme Synthesis in Pseudomonas fluorescens.

Kirkland, Jerry J. (Oklahoma State University, Stillwater), and Norman N. Durham. Correlation of carbohydrate catabolism and synthesis of macromolecules during enzyme synthesis in Pseudomonas fluorescens. J. Bacteriol. 90: 23-28. 1965.-Glucose, ribose, and fructose shorten the lag period required for synthesis of protocatechuate oxygenase. Radioactivity from uracil-2-C(14) is incorporated into the hot trichloroacetic acid-soluble fraction after a lag period of approximately 20 min after addition of protocatechuic acid. Addition of glucose or ribose simultaneously with the inducer shortens the lag period to approximately 5 min and increases the rate of uracil incorporation. The inducer must be present to initiate incorporation of radioactivity, and the exogenous carbon source accelerates incorporation but is not sufficient to initiate synthesis by itself. The addition of protocatechuic acid increases the rate and total incorporation of radioactivity from uniformly labeled glucose or ribose-1-C(14) into the hot trichloroacetic acid-soluble fraction. Ribose decreases the incorporation of radioactivity from uniformly labeled glucose into the hot trichloroacetic acid-soluble fraction, and glucose shows a similar effect on incorporation of radioactivity from ribose-1-C(14), indicating the two sugars are serving in the same capacity to enhance enzyme synthesis. Radioactivity from glucose-1-C(14) is not incorporated into the hot trichloroacetic acid-soluble fraction. The results suggest that glucose and ribose shorten the lag period for inducible enzyme formation by serving as a "specific" carbon source for synthesis of macromolecules such as ribonucleic acid.     

Incorporation of 5-Methyl- and 5-Hydroxy-Tryptophan into the Protein of Bacillus subtilis

Addition of the tryptophan analogues 5-methyl-tryptophan, 5-hydroxy-tryptophan, and 7-aza-tryptophan, during tryptophan starvation of a tryptophan auxotroph of Bacillus subtilis, stimulated amino acid incorporation. Two of the analogues tested, 5-methyl-tryptophan and 5-hydroxy-tryptophan, competed with each other, but their addition did not prevent tryptophan incorporation into acid-insoluble material. The incorporation of tryptophan and 5-hydroxy-tryptophan was stimulated when a mixture of phenylalanine and tyrosine was present in the medium. The two analogues 5-methyl-tryptophan and 5-hydroxy-tryptophan were recovered in protein hydrolysates of analogue-grown cultures, and there is evidence suggesting that the analogues are not chain terminators. Neither analogue prevented the polysome degradation that occurs during tryptophan starvation.     

The interaction of xylosyltransferase and glucuronyltransferase involved in glucuronoxylan synthesis in pea (Pisum sativum) epicotyls.

A particulate enzyme preparation from etiolated pea (Pisum sativum) epicotyls was found to incorporate xylose from UDP-D-xylose into beta-(1----4)-xylan. The ability of this xylan to act as an acceptor for incorporation of [14C]glucuronic acid from UDP-D-[14C]glucuronic acid in a subsequent incubation was very limited, even though glucuronic acid incorporation was greatly prolonged when UDP-D-xylose was present in the same incubation as UDP-D-[14C]glucuronic acid. This indicated that glucuronic acid could not be added to preformed xylan. However, the presence of UDP-D-glucuronic acid inhibited incorporation of [14C]xylose from UDP-D-[14C]xylose into beta-(1----4)-xylan, and neither S-adenosylmethionine nor acetyl-CoA stimulated either the xylosyltransferase or the glucuronyltransferase.     

Parathyroid hormone-mediated incorporation of 32P-orthophosphate into phosphatidic acid and phosphatidylinositol in renal cortical slices.

Parathyroid hormone increased the incorporation of Na2H32PO4 into phosphatidic acid and phosphatidylinositol in cat renal cortical slices. Incorporation was not observed into any other phospholipid. The effects were seen as early as one minute for phosphatidic acid and ten minutes for phosphatidylinositol. 8-Bromoadnosine 3',5'-monophosphate did not mimic the effects of parathyroid hormone. Concentrations of parathyroid hormone, 1 x 10(-8)M to 1 x 10(-7)M, which increased the incorporation of 32p into phosphatidic acid and phosphatidylinositol maximally, did not alter tissue cyclic AMP levels suggesting that the incorporation of 32p was independent of cyclic AMP.