The genus Thapsia as a source of petroselinic acid

We describe the results from the isolation and structural identification of the acylglycerol constituents of fruits from wild plants belonging to different species of Thapsia (Apiaceae). The isolated lipid fractions were analyzed and characterized by chemical, chromatographic, and spectroscopic means. In particular, 13C nuclear magnetic resonance data allowed the identification of petroselinic acid as the major fatty acid esterified to glycerol in the fruit oils from all the plant samples. This was also confirmed by gas chromatography (GC) and GC-mass spectrometry analyses of fatty acid methyl and butyl esters derivatives from Thapsia oil. The genus Thapsia should be regarded as a useful source for the extraction of petroselinic acid, which represents an important oleochemical raw material.

Separation of glyceride positional isomers by silver ion chromatography

Separation of triglyceride and diglyceride positional isomers by silver ion high-performance liquid chromatography coupled with an evaporative light-scattering detector is described. The triglyceride isomers had a fatty acid composition of CLC and CCL, where C and L were caprylic acid and linoleic acid, respectively. Diglyceride isomers, 1,2(2,3)-diglyceride and 1,3-diglyceride, which contained caprylic acid were separated too. A solvent system based on n-hexane, 2-propanol, ethyl acetate, and acetonitrile with a flow-rate of 0.8 ml/min was developed. Calibration curves of CLC and CCL were achieved with triolein as internal standard. Using this method, the incorporation of linoleic acid onto specific a position of glycerol backbone can be monitored.

A new phenolic compound from Nigella damascena seeds

A new phenolic ester has been isolated from the seeds of Nigella damascena and the structure was established as 1-O-(2,4-dihydroxy)phenylacetyl glycerol (1) by 1H and 13C-NMR spectral data and EI-MS analysis.

2-arachidonyl glyceryl ether, an endogenous agonist of the cannabinoid CB1 receptor

Two types of endogenous cannabinoid-receptor agonists have been identified thus far. They are the ethanolamides of polyunsaturated fatty acids--arachidonoyl ethanolamide (anandamide) is the best known compound in the amide series--and 2-arachidonoyl glycerol, the only known endocannabinoid in the ester series. We report now an example of a third, ether-type endocannabinoid, 2-arachidonyl glyceryl ether (noladin ether), isolated from porcine brain. The structure of noladin ether was determined by mass spectrometry and nuclear magnetic resonance spectroscopy and was confirmed by comparison with a synthetic sample. It binds to the CB(1) cannabinoid receptor (K(i) = 21.2 +/- 0.5 nM) and causes sedation, hypothermia, intestinal immobility, and mild antinociception in mice. It binds weakly to the CB(2) receptor (K(i) > 3 microM).

Do glycerolipids display lateral heterogeneity in the thylakoid membrane?

The lateral heterogeneity of lipids in the thylakoid membrane has been questioned for over 20 yrs. It is generally believed that glycerolipids are asymmetrically distributed within the plane of the membrane. In the present investigation, we isolated several thylakoid membrane domains by using sonication followed by separation in an aqueous dextran-polyethylene glycol two-phase system. This technique, which avoids detergent treatments, allowed us to obtain stroma and grana lamellae vesicles as well as grana central core and grana margin vesicles from thylakoids. The relative distribution of the four lipid classes, i.e., monogalactosyldiacylglycerol, digalactosyldiacylglycerol, sulfoquinovosyldiacylglycerol, and phosphatidylglycerol, was found to be statistically identical in all four thylakoid fractions and in whole thylakoids. Similarly, the relative amount of fatty acids in each individual lipid and the eight main phosphatidylglycerol molecular species was identical in all thylakoid membrane fractions tested as well as in the intact thylakoid membrane. Based on presently available procedures for obtaining thylakoid subfractions that are unable to discriminate microdomains within the membrane, it is concluded that glycerolipids are evenly distributed within the plane of the thylakoid membrane. These data are discussed in terms of "bulk" and "specific" lipids.

Occurrence of a novel cannabimimetic molecule 2-sciadonoylglycerol (2-eicosa-5',11',14'-trienoylglycerol) in the umbrella pine Sciadopitys verticillata seeds

The umbrella pine Sciadopitys verticillata seeds were found to contain a substantial amount (16.7 nmol/g) of sciadonic acid (all-cis-5,11,14-eicosatrienoic acid)-containing 2-monoacylglycerol, i.e., 2-sciadonoylglycerol (2-eicosa-5',11',14'-trienoylglycerol). Because the structure of 2-sciadonoylglycerol closely resembles that of 2-arachidonoylglycerol, the endogenous natural ligand for the cannabinoid receptor, we examined whether or not 2-sciadonoylglycerol exhibits cannabimimetic activity using NG108-15 neuroblastomaxglioma hybrid cells which express the cannabinoid CB1 receptor. We found that 2-sciadonoylglycerol induces rapid transient elevation of intracellular free Ca2+ concentration in NG108-15 cells through a cannabinoid CBI receptor-dependent mechanism similar to the case of 2-arachidonoylglycerol, yet the activity of 2-sciadonoylglycerol was apparently lower than that of 2-arachidonoylglycerol. The activity of 2-sciadonoylglycerol was detectable from 3-10 nM, reaching a maximum at around 10 microM. To our knowledge, this is the first report showing the occurrence of a cannabimimetic monoacylglycerol in higher plants.

Reinvestigation of positional distribution of fatty acids in docosahexaenoic acid-rich fish oil triacyl-sn-glycerols

Positional distribution of fatty acids in triacyl-sn-glycerols of docosahexaenoic acid (DHA)-rich tuna orbital and bonito head oils has been reanalyzed by a method based on chromatographic separation of isomeric and enantiomeric monoacyl-sn-glycerol (MAG) derivatives. When boric acid thin-layer chromatography (TLC) was used for separation of 1(3)- and 2-MAG analytical intermediates, the stereospecific analysis showed the preferential association of DHA to the sn-2 position followed by the sn-3 position. This distribution pattern differed from that obtained by silicic acid TLC of their bis-3,5-dinitrophenylurethane (DNPU) derivatives. Reversed-phase high-performance liquid chromatography elution profiles of 1(3)- and 2-MAG intermediates revealed that 1(3)- and 2-MAG made up of both short- and long-chain lengths cannot be clearly resolved by TLC after preparation of the DNPU derivatives. The 1(3)- and 2-MAG must be resolved by boric acid TLC prior to derivatization.

High resistance to oxygen radicals and heat is caused by a galactoglycerolipid in Microbacterium sp. M874

Microbacterium sp. M874 produced a glyceroglycolipid, di-O-12-methyl-tetradecanoyl-3-O-beta-D-galactopyranosyl-sn-glycerol, at about the 50 microM level. Though the strain was highly resistant to tertiary-butyl hydroperoxide (tBHP) in a glycolipid-productive medium, the resistance was reduced in a nonproductive medium. Exogenous addition of the glycolipid to the nonproductive culture restored the resistance. This addition also increased the resistance to heat, ethanol, and 4-chloro-1-naphthol, in which oxygen radicals might participate. The parallel relationship found in strain M874 mutants between glycolipid productivity and resistance to tBHP or heat suggested that the resistance was mainly caused by the glycolipid. On addition of the glycolipid to a glycolipid-nonproductive culture, it was immediately incorporated into the cells and functioned as an anti-oxygen radical reagent. Thereafter, its intracellular level remained largely unchanged for at least 5 h, even in the presence of tBHP, and its activity was maintained. The glycolipid at 142 microM was sufficient to prevent the cytotoxicity induced by 88.9 mM tBHP. The glycolipid production was not induced by pretreatment with a low level of tBHP or a sublethal heat shock. In brief, the glycolipid might play an essential role in the prevention of damage by oxygen radicals in the glycolipid-producing bacterium.

A sensitive endocannabinoid assay. The simultaneous analysis of N-acylethanolamines and 2-monoacylglycerols

Mammalian cells produce both N-arachidonoylethanolamine (20:4n-6 NAE, anandamide) and 2-arachidonoylglycerol (2-AG), lipid signaling molecules that activate cannabinoid receptors. Because both agonists occur in the presence of receptor-inactive congeners, we have developed a sensitive method for the simultaneous assay of N-acylethanolamines (NAEs) and 2-monoacylglycerols (2-MAG). These lipid classes are isolated from total lipids by solid phase extraction and converted to tert-butyldimethylsilyl (tBDMS) derivatives in the presence of deuterated analogs. The tBDMS derivatives are analyzed by gas chromatography/mass spectrometry using selected ion monitoring programs specific for NAE and 2-MAG. Individual NAEs and 2-MAGs can be quantified in the nanogram and subnanogram range. The NAE and 2-MAG compositions of rat organs and cultured JB6 cells are reported.

Polar glycerolipids of Chlamydomonas moewusii

The fatty acid and polar lipid compositions of the unicellular green alga Chlamydomonas moewusii were characterized. Since this organism is an important plant model for phospholipid-based signal transduction, interest was focused on the lipids phosphatidic acid, phosphatidylinositolphosphate and phosphatidylinositolbisphosphate. A phosphatidylinositol:phosphatidylinositolphosphate: phosphatidylinositolbisphosphate ratio of 100:1.7:1.3 was found. The polyphosphoinositides accounted for 0.8 mol% of the total phospholipids and their fatty acid compositions were similar to that of phosphatidylinositol except for the enrichment of linolenic acid in phosphatidylinositol phosphate. Phosphatidic acid accounted for 0.67 mol% of the phospholipids. Major structural glycerolipids were monogalactosyldiacylglycerol (35 mol%), digalactosyldiacylglycerol (15 mol%), sulfoquinovosyldiacylglycerol (10 mol%), diacylglyceryltrimethylhomoserine (16 mol%), phosphatidylglycerol (9 mol%), phosphatidylethanolamine (8 mol%) and phosphatidylinositol (6 mol%). Relative changes in the total fatty acid compositions found during growth on nutrient-limited medium reflected mainly alterations in the compositions of the chloroplast lipids phosphatidylglycerol and monogalactosyldiacylglycerol. [32P]Pi-incorporation studies revealed that it took 6 days before the amount of label in the major phospholipids was proportional to their abundance.

Inactivation of microsomal triglyceride transfer protein impairs the normal redistribution but not the turnover of newly synthesized glycerolipid in the cytosol, endoplasmic reticulum and Golgi of primary rat hepatocytes

The requirements for microsomal triglyceride transfer protein (MTP) during the turnover and transfer of glycerolipids from intracellular compartments into secretory very low-density lipoprotein (VLDL) were studied by pre-labelling lipids with [(3)H]glycerol and [(14)C]oleate in primary cultures of rat hepatocytes. The intracellular redistribution of pre-labelled glycerolipids was then compared at the end of subsequent chase periods during which the MTP inhibitor BMS-200150 was either present or absent in the medium. Inhibition of MTP resulted in a decreased output of VLDL triacylglycerol (TAG) and a delayed removal of labelled TAG from the cytosol and from the membranes of the smooth endoplasmic reticulum (SER), the cis- and the trans-Golgi. Inactivation of MTP did not decrease the bulk lipolytic turnover of cellular TAG as reflected by changes in its [(3)H]glycerol:[(14)C]oleate ratios. However, a larger proportion of the resultant TAG fatty acids was re-esterified and remained with the membranes of the various subcellular fractions rather than emerging as VLDL. The effects of BMS-200150 on the pattern of phospholipid (PL) mechanism and redistribution suggested that inhibition of MTP prevented the normal lipolytic transfer of PL-derived fatty acids out of the SER, cis- and trans-Golgi membrane pools. Finally, changes in the (14)C specific radioactivities of the cytosolic and membrane pools of TAG suggested that inhibition of MTP prevented a normal influx of relatively unlabelled fatty acids into these pools during the chase period.

[Steroids and lipids from Spirodela polyrrhiza]

Two steroids and two lipids were isolated from the ethanolic extract of Spirodela polyrrhiza. Their structures were identified by spectral analysis and chemical evidence, which were identified as stigmasterol, monopalmitic glycerate, daucosterol and palmitic acid. Monopalmitic glycerate was discovered from this plant for the first time.

An entourage effect: inactive endogenous fatty acid glycerol esters enhance 2-arachidonoyl-glycerol cannabinoid activity

2-Arachidonoyl-glycerol (2-Ara-GI) has been isolated from various tissues and identified as an endogenous ligand for both cannabinoid receptors, CB1 and CB2. Here we report that in spleen, as in brain and gut, 2-Ara-GI is accompanied by several 2-acyl-glycerol esters, two major ones being 2-linoleoyl-glycerol (2-Lino-Gl) and 2-palmitoyl-glycerol (2-Palm-Gl). These two esters do not bind to the cannabinoid receptors, nor do they inhibit adenylyl cyclase via either CB1 or CB2; however, they significantly potentiate the apparent binding of 2-Ara-Gl and its apparent capacity to inhibit adenylyl cyclase. Together these esters also significantly potentiate 2-Ara-Gl inhibition of motor behavior, immobility on a ring, analgesia on a hot plate and hypothermia caused by 2-Ara-Gl in mice. 2-Lino-Gl, but not 2-Palm-GI, significantly inhibits the inactivation of 2-Ara-Gl by neuronal and basophilic cells. These data indicate that the biological activity of 2-Ara-Gl can be increased by related, endogenous 2-acyl-glycerols, which alone show no significant activity in any of the tests employed. This effect ('entourage effect') may represent a novel route for molecular regulation of endogenous cannabinoid activity.

Reassessment of stereochemical configuration of natural phosphatidylglycerols by chiral-phase high-performance liquid chromatography and electrospray mass spectrometry

Using chiral-phase high-performance liquid chromatography (HPLC) and electrospray ionization-mass spectrometry (ESI/MS), we have redetermined the stereochemical configuration of some natural and synthetic phosphatidylglycerols (PG). For this purpose, the synthetic and natural PG were converted to their bis-3,5-dinitrophenylurethanes (DNPU), which were separated by HPLC using two columns having chiral phases of opposite configuration, (R)-(+)- and (S)-(-)-1-(1-naphthyl)ethylamine polymers. The molecular species were identified by on-line negative-ion ESI/MS. Absolute configurations of the resolved peaks were assigned by comparison with the elution order of the corresponding 1(3)-monoacyl-sn-glycerol enantiomers as bis-DNPU derivatives on the same column. The results clearly showed that the PG from cabbage leaf lipids and soybean phospholipids consisted of single R,S isomers (1,2-diacyl-sn-glycero-3-phospho-1'-sn-glycerols), despite the presence of nonstereospecific phospholipase D in the tissues. On the other hand, the PG derived from egg yolk phosphatidylcholine and glycerol by transphosphatidylation with cabbage phospholipase D was a mixture of 45% R,S isomers (1, 2-diacyl-sn-glycero-3-phospho-1'-sn-glycerols) and 55% R,R isomers (1,2-diacyl-sn-glycero-3-phospho-3'-sn-glycerols). The PG from Escherichia coli lipids was a mixture of 89% R,S and 11% R,R isomers. The present study demonstrates that chiral-phase HPLC and negative-ion ESI/MS provide direct and unambiguous information about the configuration, identity, and quantity of molecular species in natural and synthetic PG.

Induced termination of pregnancy by purified extracts of Azadirachta Indica (Neem): mechanisms involved

PROBLEM

To develop a self-administered, orally delivered method for abrogation of early pregnancy.

METHOD

Use of purified Neem extracts containing immunomodulators stimulating Th1 cells and macrophages; test animals, rats, baboons, and monkeys, onset of pregnancy confirmed by surgery and counting of implants on day 7 in rats and by chorionic gonadotropin (CG) and progesterone assays in primates; termination defined by complete resorption on day 15 in rats and by bleeding and decline of CG and progesterone in baboons.

RESULTS

Pregnancy was terminated successfully in both rodents and primates with no significant side effects. Fertility was regained in both species after one or two irregular cycles. Progeny born had normal developmental landmarks and mothered normal litters in the course of time. The active principle in Neem has been partially fractionated by activity-guided purification. A cascade of events are involved in abrogation of pregnancy. In primates, a decrease in progesterone is an early event. A transient increase in CD4 and CD8 cells is noted in spleen at 96 hr and in mostly CD8 cells in mesenteric lymph nodes. Treatment causes an elevation of both immunoreactive and bioactive TNF-alpha and gamma-interferon in serum, mesenteric lymph nodes, and foetoplacental tissue.

CONCLUSION

Immunomodulators of plant origin are potentially usable for termination of unwanted pregnancy

Biologically active acylglycerides from the berries of saw-palmetto (Serenoa repens)

Brine shrimp lethality-directed fractionation of the 95% EtOH extract of the powdered, dried berries of Serenoa repens (Bart.) Small (saw-palmetto) (Palmae) led to the isolation of two monoacylglycerides, 1-monolaurin (1) and 1-monomyristin (2). Compounds 1 and 2 showed moderate biological activities in the brine shrimp lethality test and against renal (A-498) and pancreatic (PACA-2) human tumor cells; borderline cytotoxicity was exhibited against human prostatic (PC-3) cells. The fruits and extracts of saw-palmetto are taken orally as an herbal medicine to prevent prostatic hyperplasias.

Purification and characterization of deep sea shark Centrophorus squamosus liver oil 1-O-alkylglycerol ether lipids

The 1-O-alkylglycerol composition of the liver oil of the deep sea shark Centrophorus squamosus, a species which provides edible flesh, has been determined. After various fractionations of the oil, the unsaponifiable fraction was characterized by means of gas chromatography/mass spectrometry, electron impact, and positive-ion chemical ionization. The oil is composed of 60% unsaponifiable matter, containing 45% squalene, 4.5% cholesterol, and 10% of linear saturated and monounsaturated glycerol ethers with 14-18 carbon atoms. After a first separation by chromatography on silicic acid, monounsaturated glycerol ethers have been separated from the saturated homologues, in particular from 1-O-octadecylglycerol (batyl alcohol) and 1-O-hexadecylglycerol (chimyl alcohol), via urea complexation. This newer application of the urea method, already used in the past to extract saturated from polyunsaturated fatty acids, allowed the purification of the main components of the complex unsaturated glycerol ether fraction, namely, 1-O-octadecen-9'ylglycerol (selachyl alcohol) and 1-O-hexadecen-9'ylglycerol.

Growth-dependent accumulation of monoalkylglycerol in Madin-Darby canine kidney cells. Evidence for a role in the regulation of protein kinase C

1-O-Alkyl-sn-glycerol (alkylglycerol) forms the backbone of complex ether-linked glycerolipids, including biologically active lipids such as platelet-activating factor. Synthetic alkylglycerol itself possesses several potent pharmacological activities and has been shown to inhibit protein kinase C (PKC) in vitro. In spite of these properties, free alkylglycerol has been regarded only as a potential product of the inflammatory degradation of complex ether lipids rather than a natural cell constituent. To explore the possibility that endogenous alkylglycerol functions as a physiological regulator in normal cells, we measured its content, along with related monoglycerides and diglycerides, by high performance liquid chromatography and gas-liquid chromatography in Madin-Darby canine kidney (MDCK) cells. The content of free alkylglycerol increased up to 20-fold during the growth of MDCK cell cultures to a confluent density. The increase was greatest during the log phase of growth, in which the content of alkylglycerol rose from 6.0 +/- 1.3 nmol/10(8) cells in preconfluent cultures to 23.6 +/- 3.4 nmol/10(8) cells in confluent cultures. Analysis of the molecular species of alkylglycerol showed that the higher content in quiescent MDCK cells was due primarily to an increase in 1-O-octadecyl-sn-glycerol. In contrast, the levels of monoacylglycerol and the PKC activator diacylglycerol were lower in confluent, quiescent cultures than in preconfluent, proliferating cultures. A similar pattern of changes in the monoglyceride and diglyceride content was observed in interleukin-3-dependent CFTL-12 mast cells when cell proliferation was blocked by growth factor withdrawal. Growth of MDCK cells to a confluent density resulted in a decrease in particulate PKC enzyme activity to a level that was only 6% of that in proliferating cells. To explore whether the accumulation of cellular alkylglycerol contributes to growth-dependent changes in PKC activity, we examined the effects of adding alkylglycerol to the activity and subcellular distribution of the enzyme in MDCK cells. Treatment of cells with 1-O-dodecyl-sn-glycerol resulted in a decrease in the activity of membrane-associated PKC activity and inhibited 12-O-tetradecanoylphorbol-13-acetate-stimulated translocation of PKC from the cytosol to the membrane fraction. Alkylglycerol was also shown to inhibit the activity of purified PKC in vitro when present at levels similar to that of the diacylglycerol activator. We propose that the accumulation of alkylglycerol during the growth of MDCK cells to a confluent density contributes to the decrease in PKC activity. The control of cellular alkylglycerol levels may be a novel mechanism for the regulation of cellular physiology.

AKD-2A, B, C and D, new antibiotics from Streptomyces sp. OCU-42815. Taxonomy, fermentation, isolation, structure elucidation and biological activity

An antibiotic complex, AKD-2, was isolated from the mycelial cake of Streptomyces sp. OCU-42815. The lipophilic substances in this complex were further purified by a recycling HPLC procedure and were designated AKD-2A, C and D. AKD-2B was obtained as a mixture of AKD-2B1 and AKD-2B2. These substances were identified as monoglycerides having branched chain fatty acids and exhibited both antibacterial and antifungal activities.

Comparison of extraction procedures on the immunocontraceptive activity of neem seed extracts

Azadirachta indica (Neem) seed extracts are known to activate the local cell-mediated immune reactions after a single intrauterine administration, leading to a long term reversible block of fertility. In order to identify and characterize the active fraction responsible for this activity, neem seeds were extracted by both mechanical expression and solvent extraction using a range of polar to non-polar solvents which yielded 3 broad fractions. The mechanically expressed oil was fractionated using different approaches and studied for antifertility activity. The hexane extract and a corresponding column fraction showed potent and reproducible antifertility activity. Other fractions were less stable with regard to reproducibility of effects and composition. It is our conclusion that for subsequent fractionation to reach the last active fraction, the hexane extract is the most useful starting material.

Long and very long chain polyunsaturated fatty acids of the n-6 series in rat seminiferous tubules. Active desaturation of 24:4n-6 to 24:5n-6 and concomitant formation of odd and even chain tetraenoic and pentaenoic fatty acids up to C32

The formation of long and very long chain (VLC) n-6 polyunsaturated fatty acids (PUFA) in isolated rat seminiferous tubules was investigated by following the metabolism of three 1-14C-labeled n-6 tetraenoic fatty acids (20:4, 24:4, and 32:4) and [U-14C]acetate. In contrast to [14C]32:4, which was poorly incorporated and altered, [14C]20:4 and [14C]24:4 were efficiently taken up by the tubules, esterified into lipids, elongated to VLCPUFA, and desaturated to pentaenoic fatty acids; the rate of [14C]24:4 desaturation to [14C]24:5 was notably high. The main products with [14C]acetate as precursor were labeled saturates and VLCPUFA, most of the label in tetraenoic and pentaenoic acids appearing in 24:4 and 24:5, respectively. These two C24 polyenes, connected by a delta 6 desaturation, may play a central role in n-6 PUFA metabolism, in their capacity as potential precursors of longer polyenes via elongation and of shorter ones, such as 22:5n-6, via retroconversion. Triacylglycerols, rich in C22 and C24 polyenes, incorporated the greatest amounts of both [14C] acetate-derived and exogenous 14C-PUFA, suggesting that this lipid class is involved in the traffic and metabolism of testicular PUFA. The detection of a series of unusual odd-chain tetraenoic and pentaenoic acids, also labeled with [U-14C]acetate, suggests that a PUFA chain shortening mechanism occurs in testis involving alpha- in addition to beta-oxidation. We speculate that alpha-oxidation plays a role in the retroconversion of PUFA.

Trypanosome metabolism of myristate, the fatty acid required for the variant surface glycoprotein membrane anchor

The trypanosome variant surface glycoprotein (VSG) is anchored to the outer leaflet of the parasite plasma membrane by a glycosyl phosphatidylinositol (GPI). The VSG anchor is unique among GPIs in containing exclusively dimyristoylglycerol as its lipid moiety. Myristate is incorporated into the anchor precursor by sequential deacylation and specific reacylation with myristate. Although myristate is required for the VSG anchor, trypanosomes cannot synthesize this fatty acid and must import their entire supply from the host bloodstream, where it exists in low abundance. Chemical analysis of these parasites reveals that most of their myristate is in VSG protein, with no major lipid storage form. Unexpectedly, when these cells are radiolabeled with [3H]myristate in culture, most of the label is incorporated into phospholipids, with little into VSG. This apparent contradiction is explained by the fact that trypanosomes in culture medium elongate much of the [3H]myristate into palmitate and stearate, probably because the medium (with only 5% serum) contains limiting amounts of these fatty acids. In contrast, trypanosomes radiolabeled in whole blood (with higher concentrations of palmitate and stearate) do not modify most of the [3H]myristate, and instead utilize the major portion of it for GPI synthesis. Our studies suggest that bloodstream trypanosomes have evolved highly efficient means of directing myristate into the GPI biosynthetic pathway.

The production of a bactericidal monoglyceride in staphylococcal abscesses

The treatment of abscess homogenates with calcium ionophores stimulated the production of a bactericidal lipid with properties indistinguishable from those of a previously unidentified bactericidal lipid that had been detected in staphylococcal abscesses. The lipid was identified as a monoglyceride by thin layer chromatography. It resembled the unidentified lipid in that it had a high specific activity, exhibited differential activity, was inhibited by Staphylococcus aureus delta toxin, lecithin and Ca++, and its activity was reduced by oxidation. Stimulation of monoglyceride production by calcium ionophore requires the joint presence of components from the sedimented and supernatant fractions of abscess homogenates, and was not produced if boiled homogenate was used. The addition of verapamil interfered with the production of monoglyceride in homogenates treated with calcium ionophore. Monoglyceride was produced only in abscess homogenates and not in homogenates of other normal tissues or tissues taken from mice infected with S. aureus. Calcium ionophore could be replaced by inositol triphosphate, suggesting that monoglyceride production involved the release of calcium from intracellular stores. The 2-monoglyceride was the form originally produced in abscess homogenates, but this spontaneously isomerized to the 1-monoglyceride. The fatty-acid moiety of the monoglyceride consisted primarily of 16:0 and 16:1 fatty acids.

6-Gingesulfonic acid, a new anti-ulcer principle, and gingerglycolipids A, B, and C, three new monoacyldigalactosylglycerols, from zingiberis rhizoma originating in Taiwan

By monitoring the effects on HCl/ethanol-induced gastric lesions in rats, a new antiulcer principle named 6-gingesulfonic acid was isolated from Zingiberis Rhizoma, the dried rhizome of Zingiber officinale Roscoe (cultivated and processed in Taiwan) together with three new monoacyldigalactosylglycerols named gingerglycolipids A, B and C. Their chemical structures were elucidated on the basis of chemical and physicochemical evidence. 6-Gingesulfonic acid showed more potent anti-ulcer activity than 6-gingerol and 6-shogaol.