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PubMed2001

Effects of phosphoprotein phosphatase inhibitors (phenylarsine oxide and cantharidin) on Tetrahymena.

The effects of phenylarsine oxide (PAO) (phosphotyrosine phosphatase inhibitor) and cantharidin (serine/threonine phosphatase [PP2A] inhibitor) treatments were analysed on the synthesis of phospholipids and glycolipids, and on the cytoskeletal elements (F-actin and tubulin containing structures) of Tetrahymena pyriformis. Both phosphatase inhibitors reduced the amount of incorporated 32P of the whole phospholipid content, but the ratio of phosphatidylserine (PS) and phosphatidylcholine (PC) to the total phospholipid content increased. Both treatments influenced the phosphatidylinositol (PI) system. These inhibitors also influenced the incorporation of palmitic acid into the phospholipids: in general PAO decreased, whereas cantharidin increased the amount of incorporated palmitic acid; 1 microM cantharidin significantly increased the labelling of PE and PA. The incorporation of mannose and glucosamine was influenced differently by PAO and cantharidin treatments: the latter elevated, while PAO decreased the labelling of glycolipids with these sugars. The effects of these treatments were visible also in the case of confocal scanning laser microscopic (CSLM) images: after treatments with both inhibitors, the F-actin containing cortical elements were destroyed, but the tubulin containing ones (longitudinal and transversal microtubules, oral apparatus and deep fibres) did not display significant alterations. The different effects of phosphatase inhibitors were visible also on the scanning electron microscopic (sEM) images: cantharidin treatments (1 microM) decreased the amount of dissolved membrane lipids after chemical dehydration of the cells with 2, 2-dimethoxy propane (DMP), but in the case of treatments with 10 microM, the surface pattern of cells was similar to the controls. On the other hand, after PAO treatments the surface pattern of Tetrahymena showed significant alterations. Both phosphatase inhibitors inhibited the phagocytotic activity of the cells. On the basis of present experiments we suppose that these treatments are able to influence signalling systems (e.g. PI) of Tetrahymena, and also the structure of the cytoskeleton and the functions (e.g. phagocytosis) which are connected with skeletal elements.

Actins↗
PubMed1979

Fetal to maternal transfer of palmitic and linoleic acids across the sheep placenta.

Maternal and fetal blood samples were obtained at 2.5, 10 and 20 min after the injection of 3H-palmitic acid and 14C-linoleic acid into the fetal circulation of pregnant ewes. 3H-palmitic acid was easily detected in the maternal circulation within 2.5 min after its injection into the fetus resulting in an appreciable accumulation in the maternal plasma by the 20th min after injection. In contrast the presence of 14C-linoleic acid in the maternal circulation was barely detectable over the 20-min sampling period. The concentrations of total lipid and unesterified fatty acids within the fetal plasma were considerably lower than in the maternal plasma thereby providing an adverse concentration gradient for the passage of fatty acids between fetus and mother. The differential permeability of the placenta to the passage of the 3H-palmitic acid and 14C-linoleic acid is discussed in relation to their passage from fetus to mother in non-ruminant species and the adverse essential fatty acid status known to exist in the developing ruminant fetus.

Animals↗
PubMed1994

Psyllium husk fibre supplementation to soybean and coconut oil diets of humans: effect on fat digestibility and faecal fatty acid excretion.

The effects of psyllium fibre supplementation to polyunsaturated fatty acid rich soybean oil and saturated fatty acid rich coconut oil diets on fat digestibility and faecal fatty acid excretion were investigated in healthy humans. The study consisted of four 7-day experimental periods. Participants consumed soybean oil (SO), soybean oil plus psyllium fibre (20 g/day) (SO+PF), coconut oil (CO) and coconut oil plus psyllium fibre (20 g/day) (CO+PF) diets. Laboratory diet provided 30% calories from fat (20% from test oils and 10% from basal diet), 15% calories from protein and 55% calories from carbohydrate. Fat digestibility was significantly lower and faecal fat excretion was significantly higher with SO+PF diet than SO diet and with CO+PF diet than CO diet. Faecal excretion of myristic and lauric acids was not affected by test diets. Percent faecal palmitic acid excretion was significantly higher during psyllium supplementation periods. Higher faecal linoleic acid excretion was observed with soybean oil diets compared with coconut oil diets. Increased faecal fat loss, decreased fat digestibility and increased faecal palmitic acid excretion with psyllium supplementation may partly explain the hypocholesterolaemic action of psyllium fibre.

Coconut Oil↗
PubMed1985

Cerulenin inhibition of lipid synthesis and its reversal by exogenous fatty acids in Mycobacterium smegmatis ATCC 607.

Cerulenin inhibited the lipid synthesis of Mycobacterium smegmatis ATCC 607 over the range of 0.5-1.8 microgram/mL with complete inhibition at 1.8 microgram/mL, as monitored by [14C]glycerol incorporation into lipids. Exogenous fatty acids failed to restore the lipid synthesis at 1.8 microgram/mL; however, the addition of palmitic acid to the growth medium partially restored the lipid synthesis when cerulenin concentration was decreased to 1.6 microgram/mL. Fatty acid analysis of cerulenin plus palmitic acid supplemented cultures revealed that exogenously supplied fatty acid was incorporated into cellular phospholipids. Further investigations with 1.6 microgram/mL of cerulenin and [14C]acetate and [32P]orthophosphoric acid showed that cerulenin inhibited the synthesis of saturated plus unsaturated fatty acids and phospholipids. Pulse-chase studies with [14C]acetate revealed decreased synthesis and degradation of each of the phospholipid components.

Antifungal Agents↗
PubMed1976

Determination of free fatty acids as pentafluorobenzyl esters by electron capture gas chromatography.

A method for the determination of free fatty acids in minute serum samples has been developed. The acids are esterified by extractive alkylation, using tetrabutylammonium as a counter ion and pentafluorobenzyl bromide as alkylating reagent. The derivatization of palmitic acid required a reaction time of 25 min. The excess of pentafluorobenzyl bromide is removed by coupling it with a phenoalkylamine and extraction of the product into an acidic aqueous phase. Quantitation is carried out by gas chromatography with electron capture detection. The precision achieved in the determination of 6.2 mug of palmitic acid in 50 mul of mouse serum was 6.1% (S.D.).

Alkylation↗
PubMed1980

The influence of paraquat on the in vivo incorporation of lecithin precursors in lung tissue and 'alveolar' lecithin.

Rats were injected with paraquat (1,1'-dimethyl-4,4'-bipyridyliumdichloride, 35 mg/kg) and killed 14 or 48 h later. Twelve hours prior to sacrifice labelled choline or palmitic acid was injected. Immediately after sacrifice alveolar lavage was performed in situ and the lungs were removed and homogenized. Lipid extracts from lavage fluid and lung homogenates were prepared and their lecithin content analysed by thin layer chromatography. Lecithin was quantitated by phosphorous determination, the incorporation rate of the lecithin precursors in 'alveolar' and lung tissue lecithin was measured by liquid scintillation, and the fatty acid composition of lecithin was determined by gas liquid chromatography. In comparison with controls, the content of lecithin was reduced in lavage fluid from paraquat-injected rats. These animals also had reduced incorporation of choline in alveolar lecithin. The rate of incorporation of palmitic acid was the same in experimental animals and controls, so was the incorporation of choline in lung tissue lecithin. The findings suggest that paraquat interferes with the synthesis of alveolar lecithin by the phosphocholine transferase pathway, but not with the formation of lung tissue lecithin.

Animals↗
PubMed1998

Mapping fatty acid binding to beta-lactoglobulin: Ligand binding is restricted by modification of Cys 121.

Native beta-lactoglobulin (Blg) binds 1 mole of palmitic acid per mole of protein with a dissociation constant of 0.6 microM for the primary fatty acid binding site. Chemical modification of Cys 121, which lies at the external putative hydrophobic binding site of Blg, does not affect retinol or 4,4'-bis 1-(phenylamino)-8-naphthalenesulfonate (bis-ANS) binding to the protein, indicating that the incorporated appendages do not perturb the internal hydrophobic site within the beta-barrel of Blg (i.e., the retinoid site is unaffected). On the other hand, methylation of Cys 121, reduces the affinity of Blg for palmitic acid by 10-fold as monitored by intrinsic fluorescence. Modification of the Cys 121 with methylmethanethiosulfonate or a thiol-specific spin label appears to either further weaken or totally eliminate fatty acid binding, respectively, due to steric hindrance. Furthermore, this binding pattern has been independently verified using a spin labeled fatty acid analog and monitoring ESR as well as by bis-ANS fluorescence when bound to the protein. These results suggest that fatty acids bind at the "external site" of beta-lactoglobulin, between the sole alpha-helix and the beta-barrel. In addition, structural stability studies of native and chemically modified Blg appear to confirm this observation as well.

Anilino Naphthalenesulfonates↗
PubMedDate not supplied

The use of sesame oil and other vegetable oils in the inhibition of human colon cancer growth in vitro.

Sesame contains large quantities of the essential polyunsaturated fatty acid (PUFA), linoleic acid, in the form triglycerides. The antineoplastic properties of many PUFAs such as linoleic acid and their metabolites are known. We tested the hypothesis that natural vegetable oils, such as sesame oil and its component linoleic acid, when added to human colon adenocarcinoma cells growing in tissue culture would inhibit their growth and that normal colon cells would not be similarly affected. Three human colon cancer cell lines and one normal human colon cell line were exposed to the following: (1) pure linoleic acid; (2) lipase-digested sesame oil; (3) undigested sesame oil; (4) five additional common vegetable oils; (5) mineral oil. Linoleic acid inhibited the in vitro growth of all three malignant human colon adenocarcinoma cell lines. The normal colon cell line showed dramatically less inhibition of growth. Lipase-digested sesame oil (LDSO) and undigested sesame oil (UDSO) produced greater inhibition of growth of all three malignant colon cell lines than of the normal colon cells. Five other common vegetable oils containing various amounts of PUFAs such as corn, soybean, safflower, olive and coconut oils, all in their lipase-digested form, were found to dramatically inhibit the growth of the HT-29 malignant human colon cell line. Undigested olive and safflower oils also inhibited the HT-29 cells although not as markedly as the lipase-digested oils. Mineral oil did not inhibit the growth of HT-29 cells. Both lauric and palmitic acid, which are saturated fatty acids found in abundance in coconut oil inhibits the HT-29 cells more strongly than linoleic acid, while oleic acid did not inhibit. We conclude that many vegetable oils including sesame contain in vitro antineoplastic properties and that this finding warrants further investigation both in vitro and in vivo to assess their possible chemotherapeutic potential.

Adenocarcinoma↗
PubMed2001

Identification of a mammalian long chain fatty acyl elongase regulated by sterol regulatory element-binding proteins.

Fatty acids are synthesized de novo from acetyl-CoA and malonyl-CoA through a series of reactions mediated by acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS). In rodents, the principal fatty acid produced by FAS is palmitic acid (16:0). Sterol regulatory element-binding proteins (SREBPs) enhance the transcription of many genes responsible for fatty acid synthesis. In transgenic mice that overexpress SREBPs in liver, the rate of fatty acid synthesis is markedly increased, owing to the activation of these biosynthetic genes, which include ATP citrate lyase, ACC, FAS, and stearoyl-CoA desaturase. The fatty acids that accumulate in livers of SREBP transgenic mice are 18 carbons rather than 16 carbons in length, suggesting that the enzymes required for the elongation of palmitic to stearic acid may be induced. Here, we report the cDNA cloning of a murine long chain fatty acyl elongase (LCE) that was identified initially by oligonucleotide array analysis of mRNA from SREBP transgenic mouse livers. LCE mRNA is highly expressed in liver and adipose tissue. The cDNA encodes a protein of 267 amino acids that shares sequence identity with previously identified very long chain fatty acid elongases. Cells that overexpress LCE show enhanced addition of 2-carbon units to C12-C16 fatty acids. We provide evidence that LCE catalyzes the rate-limiting condensing step in this reaction. The current studies suggest that mouse LCE expression is increased by SREBPs and that the enzyme is a component of the elusive mammalian elongation system that converts palmitic to stearic acid.

Acetyltransferases↗
PubMed1986

Cyclic AMP increases incorporation of exogenous fatty acids into triacylglycerols in hamster fibroblasts.

Incorporation of various exogenous saturated or unsaturated [14C]labeled fatty acids (palmitic, stearic, oleic, linoleic and arachidonic) into triacylglycerols by hamster fibroblasts was markedly enhanced (two- to fourfold) in the presence of theophylline or dibutyryl cyclic adenosine monophosphate (dbcAMP). This effect was observed for short-term (1-6 hr) as well as long-term (15-24 hr) preincubation with dbcAMP. In the presence of sodium fluoride, a phosphoprotein phosphatase inhibitor, measurement of diacylglycerol acyltransferase (DGAT) activity in cells pretreated with dbcAMP pointed out a marked increase (3 X) in specific activity. The results suggest that DGAT activity in fibroblasts could be activated by a cAMP-dependent phosphorylation process.

Acyltransferases↗
PubMed1968

Metabolism of glycerol ether-containing lipids in dog fish (Squalus acanthias).

Dogfish (Squalus acanthias) received intrahepatic injections of either palmitic acid-1-(14)C or chimyl alcohol-1-(14)C. The lipids of the liver were then analyzed for incorporated radioactivity. The experiments with labeled palmitic acid demonstrated that fatty acids are reductively incorporated into the alkyl and alkenyl ether chains of glycerolipids. Significantly lower specific activities were found for the diacyl alk-1'-enyl ethers and diacyl glycerol ethers than for other glycerol ether-containing lipids. These compounds may therefore represent terminal points in ether-lipid metabolism. The studies with labeled chimyl alcohol indicate that dogfish liver contains enzymes that have a high capacity for oxidatively cleaving alkyl ether linkages. Furthermore, it is probable that alkyl ethers are converted directly to alkenyl ethers, possibly via a biodehydrogenation reaction.

Alcohols↗
PubMed1993

Mutations of the alpha 2A-adrenergic receptor that eliminate detectable palmitoylation do not perturb receptor-G-protein coupling.

The alpha 2A-adrenergic receptor (alpha 2AAR) is coupled to a variety of effectors via pertussis toxin-sensitive GTP-binding proteins. Like most members of the G-protein-coupled receptor superfamily, the primary structure of the alpha 2AAR possesses a putative consensus sequence for palmitoylation in the COOH terminus at Cys-442. This study demonstrates that the alpha 2AAR incorporates [3H] palmitic acid in metabolic labeling studies and that mutation of Cys-442 to Ala or Ser eliminates detectable 3H-palmitoylation. However, mutation of Cys-442 does not alter adrenergic ligand specificity or allosteric modulation by amphipathic agents, such as amiloride analogs. Since reports in the literature suggest that a homologous mutation in the beta 2-adrenergic receptor attenuates coupling to Gs (O'Dowd, B. F., Hnatowich, M., Caron, M. G., Lefkowitz, R. J., and Bouvier, M. (1989) J. Biol. Chem. 264, 7564-7569) whereas chemical removal of palmitate from bovine rhodopsin enhances coupling to Gt (Morrison, D. F., O'Brien, P. J., and Pepperberg, D. R. (1991) J. Biol. Chem. 266, 20118-20123), we examined if mutation of Cys-442 and parallel loss of detectable palmitoylation alter alpha 2AAR coupling to G-proteins. Several independent cell lines of Madin-Darby canine kidney II cells expressing wild-type (Cys-442) or mutant (Ala-442 and Ser-442) alpha 2AARs were established. Metabolic labeling of Madin-Darby canine kidney cells expressing wild-type (Cys-442) or mutant (Ala-442) alpha 2AARs with [3H]palmitic acid indicated that only wild-type Cys-442-containing receptors incorporated [3H]palmitate, monitored following isolation of the alpha 2AAR detergent extracts using yohimbine-agarose chromatography. Receptor-G-protein coupling was assessed by evaluating sensitivity of receptor-agonist interactions to guanine nucleotides in competition for [3H]yohimbine antagonist binding, guanyl-5'-yl imidotrisphosphate sensitivity of pertussis toxin-sensitive p-[125I]iodoclonidine agonist binding, and agonist-stimulated guanosine 5'-O-(thiotriphosphate) binding. Using all three approaches, no detectable change in alpha 2AAR-G-protein coupling was apparent, in contrast to apparent opposite effects on the beta 2-adrenergic receptor-Gs and rhodopsin-Gt coupling reported previously by others. One interpretation is that this conserved cysteine may play differing roles at different receptor-G-protein interfaces. Alternatively, this shared structural motif may play a role in not yet investigated pathways, such as receptor expression, turnover, and localization.

Acylation↗
PubMed1980

The metabolism of exogenous fatty acids by preimplantation mouse embryos developing in vitro.

The utilization of fatty acids from the culture medium has been examined in preimplantation mouse embryos developing in vitro. Incorporation of exogenous fatty acid into embryo lipids was examined by culturing 8-cell mouse embryos for 2h in a medium containing 0.1 mM [9, 10-3H]palmitic acid (900 mCi/mmol). Lipids were extracted from the embryos, and the total lipid extract was fractionated into various neutral lipid and polar lipid classes by thin-layer chromatography. Most of the radioactivity, over 93%, was recovered in neutral glycerides (mono- di-, and triacylglycerols). About 2% of the total radioactivity was recovered in other neutral lipid species including fatty acids, fatty alcohols, and sterol esters. The remainder of the radioactivity was recovered in polar lipids. Seventy-four per cent of the polar lipid radioactivity was present in the amine phosphatides, inositol and/or serine phosphatides, sphingomyelin, choline lysophosphatides, sulfatides, cerebrosides, and monoglycosylglycerides. Chemical degradation studies of labelled embryo lipids indicated that the tritium lable was entering into embryo lipids as the fatty acid and not via metabolic recycling. The oxidation of exogenous fatty acids by mouse embryos was assessed by incubating variously staged embryos for 4h in medium containing 0.1 mM [U-14C]palmitic acid (50 mCi/mmol) and quantitating the production of 14CO2. The rate of fatty acid oxidation was found to be relatively constant from the unfertilized egg up to the 8-cell stage and then increase significantly between the 8-cell and late blastocyst stages. The results suggest that preimplantation mouse embryos developing in vitro can utilize fatty acids from the medium both for incorporation into embryo lipids and for energy production via oxidation.

Animals↗
PubMed2003

Characterization of fatty acid synthase activity using scintillation proximity.

FAS is a 544-kDa dimeric enzyme consisting of seven functional catalytic components that synthesize long-chain fatty acids from acetyl-CoA and malonyl-CoA using NADPH as a cofactor. We have developed a novel radiometric, homogeneous procedure that directly detects FAS activity. The assay determines incorporation of [(3)H]acetyl-CoA into palmitic acid as catalyzed by FAS from rat liver. Radiolabeled palmitic acid is captured on a 384-well phospholipid-coated microtiter plate and is brought into close proximity with embedded scintillant, stimulating the emission of photons. Because it uses acetyl-CoA and malonyl-CoA as substrates, the procedure mimics the classical reductase assay. However, this method eliminates such labor-intensive steps as organic extraction, aspirations and washes, phase separations, and sample transfers. Furthermore, it offers advantages over photometric and fluorometric methods that indirectly measure FAS activity via NADPH absorbance. We present here kinetic and inhibition data for FAS using scintillation proximity. The assay is shown to be robust and reproducible.

Acetyl Coenzyme A↗
PubMed1991

Effects of maternal diabetes or in vitro hyperglycemia on uptake of palmitic and arachidonic acid by rat embryos.

Altered transfer of nutrients from mother to conceptus may be involved in the pathogenesis of the developmental disturbances in offspring of diabetic mothers. In our study, the embryonic uptake of a saturated (palmitic acid) and a nonsaturated (arachidonic acid) fatty acid was evaluated in a normal and a diabetes-like environment under in vivo and in vitro conditions that yield growth retardation and somatic malformations in the embryos. The palmitic acid uptake in embryos from diabetic rats and in embryos cultured in vitro in 30 mmol/L D-glucose did not differ from the respective controls. Only embryos cultured in the highest D-glucose concentration (60 mmol/L) showed slightly increased uptake, which suggests that alterations in palmitic acid transfer have no role in the processes of embryonic maldevelopment in diabetic pregnancy. In contrast, the results showed that a diabetes-like environment both in vivo and in vitro causes increased embryonic uptake of arachidonic acid. Consequently, if the teratogenic mechanisms of diabetic pregnancy involve decreased embryonic levels of arachidonic acid, as has been suggested, this would not be the effect of a decreased uptake per se, but rather of an altered intracellular metabolism or decreased extracellular availability of this fatty acid.

Animals↗
PubMed1995

Correlations between the intensity of fMLP-dependent respiratory burst and cellular fatty acid composition in human neutrophils.

The peripheral blood neutrophils were isolated from a group of normal subjects and their fatty acid composition determined by capillary gas-chromatography. The superoxide (O2-) release by the same cell preparation in response to formyl-methionyl-leucyl-phenylalanine was also determined following cytochrome c reduction in a microplate assay. A strong negative correlation was found between C18:2 (linoleic acid) (r = 0.703, P = 0.001) and C:16:0 (palmitic acid) (r = 0.569, P = 0.009) and fMLP-stimulated O2- release, whereas C20:4 (arachidonic acid) correlated positively (r = 0.448, P = 0.048). Other fatty acids, namely C12:0, C14:0, C16:1, C18:1, C18:3, C18:4, C20:0, C20:1, C20:2, C20:5, C22:0, C22:1, C22:6, C24:0 and C26:0, were not correlated with O2-. No correlations were found between fatty acid composition and O2- release from resting cells and from cells stimulated by phorbol-myristate acetate. These results suggest that the fatty acid composition of blood neutrophils may be a critical factor determining the capability of releasing free radicals in response to formylpeptides. Moreover, since a concomitant increase of arachidonic acid and decrease of its precursor linoleic acid has been found in high-responsive neutrophils, the rate of the enzymes of the arachidonic acid biosynthetic pathway (elongases and desaturases) appear to play an important role.

Arachidonic Acid↗
PubMed1969

Effect of mixed micellar lipid on the absorption of cholesterol and vitamin D3 into lymph.

The absorption of endogenous cholesterol, labeled with tracer doses of cholesterol (14)C or cholesterol-(3)H and of near physiological doses of vitamin D(3)-(3)H was studied in rats with cannulated intestinal lymphatics. The effects of administering mixed micellar solutions of fatty acid, monoglyceride, and bile salt on the absorption of these labeled sterols was determined. It was observed that the specific activity of free cholesterol and the amounts of vitamin D(3) appearing in lymph were significantly increased during the intraduodenal administration of mixed micellar solutions of either linoleic or palmitic acid, in contrast to control rats receiving a micellar solution of taurocholate. These increases were related linearly to the lymph triglyceride level. In addition it was observed that when the linoleic acid solution was administered there was a more marked increase in the ratio of the specific activities of free and esterified cholesterol in lymph than with either the palmitic acid or taurocholate solutions. Additional studies in rats with intact lymphatics showed that the uptake of labeled cholesterol and vitamin D(3) from the intestinal lumen into the wall was similar whether the sterols were administered in taurocholate or in mixed micellar solution. These findings suggest that mixed micellar lipid increased the rate of appearance of labeled free cholesterol and vitamin D(3) in lymph by enhancing their transport out of the intestinal mucosa, rather than by an effect on uptake.

Animals↗
PubMedDate not supplied

Hydrophobic transmembrane-peptide lipid conjugations enhance membrane binding and functional activity in T-cells.

Application of different delivery methods for therapeutic peptides has gained much attention in recent years. In this paper we conjugated a transmembrane hydrophobic peptide (core peptide; CP) derived from the T-cell antigen receptor alpha-chain sequence with either one (LP1), two (LP2), or three (LP3) palmitic acids through a Tris linkage. The effect of these lipopeptides (LPs) were compared to CP's activity both in vitro and in model membrane binding experiments using surface plasmon resonance. The influence of charged amino acids, arginine and lysine, within the CP sequence was examined by synthesizing analogues where arginine and lysine were replaced by the neutral amino acid alanine and these analogues were subsequently Tris-lipid conjugated with either one (XP1), two (XP2), or three (XP3) palmitic acids through a Tris linkage. The results indicated that the amount of irreversible binding for LPs were all greater than that of the underivatized CP in model membranes. None of the LPs could be dissociated from the liposome membranes, even after prolonged washing. Binding results for the neutral conjugates showed that only the XP1 bound to model membranes. This binding was 20% as efficient compared to LP1. In biological assays it was found that LP1 and XP1 were toxic to cells. LP3 inhibited IL-2 production more effectively than CP. Control lipopeptides (XP2, XP3) did not inhibit IL-2 production. These results demonstrate that the number of lipids conjugated to peptide, and the charged amino acids of CP, are both essential factors for peptide function and activity that can be enhanced by lipidation.

Amino Acid Sequence↗