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PubMed2004

Biomass burning as the main source of organic aerosol particulate matter in Malaysia during haze episodes.

The haze episodes that occurred in Malaysia in September-October 1991, August-October 1994 and September-October 1997 have been attributed to suspended smoke particulate matter from biomass burning in southern Sumatra and Kalimantan, Indonesia. In the present study, polar organic compounds in aerosol particulate matter from Malaysia are converted to their trimethylsilyl derivatives and analyzed by gas chromatography-mass spectrometry in order to better assess the contribution of the biomass burning component during the haze episodes. On the basis of this analysis, levoglucosan was found to be the most abundant organic compound detected in almost all samples. The monosaccharides, alpha- and beta-mannose, the lignin breakdown products, vanillic and syringic acids and the minor steroids, cholesterol and beta-sitosterol were also present in some samples. The presence of the tracers from smoke overwhelmed the typical signatures of emissions from traffic and other anthropogenic activities in the urban areas.

Air Pollution↗
PubMed1994

ATP inhibits the hydrosmotic effect of AVP in rabbit CCT: evidence for a nucleotide P2u receptor.

In rabbit renal cortical collecting tubule (CCT), perfused in vitro at 38 degrees C, ATP in concentrations of 10(-7) M and greater inhibits arginine vasopressin (AVP)-stimulated osmotic water permeability (Pf). The P1-purinergic receptor antagonist 8-phenyltheophylline did not attenuate the inhibitory action of ATP, and the poorly hydrolyzable ATP analogue, 5'-adenylylimidodiphosphate (AMP-PNP), mimicked the effect of ATP, arguing against an effect of ATP on a P1 receptor or the "P site." Purinergic receptor agonists inhibited AVP-stimulated Pf with the following rank order efficacy: ATP = ADP = UTP = AMP-PNP = alpha, beta-methylene-ATP > 2-methylthio-ATP >> AMP > adenosine, consistent with the pharmacology of a "nucleotide" receptor subtype. Pertussis toxin pretreatment attenuated the action of 10(-5) and 10(-6) MATP; however, 10(-4) MATP failed to inhibit the hydrosmotic action of forskolin or 8-bromoadenosine 3',5'-cyclic monophosphate. Pretreatment with the phosphodiesterase inhibitor RO20-1724 or indomethacin did not inhibit the action of ATP. Staurosporin and 3,4,5-trimethoxybenzoic acid 8-(diethylamino)octyl ester significantly attenuated the inhibition of Pf by lower concentrations of ATP. These data suggest that ATP activates nucleotide receptors on the CCT, mobilizing intracellular Ca2+, which inhibits the hydrosmotic action of AVP.

Adenosine Triphosphate↗
PubMed1999

Lignin-modifying enzymes of the white rot basidiomycete Ganoderma lucidum.

Ganoderma lucidum, a white rot basidiomycete widely distributed worldwide, was studied for the production of the lignin-modifying enzymes laccase, manganese-dependent peroxidase (MnP), and lignin peroxidase (LiP). Laccase levels observed in high-nitrogen (HN; 24 mM N) shaken cultures were much greater than those seen in low-nitrogen (2.4 mM N), malt extract, or wood-grown cultures and those reported for most other white rot fungi to date. Laccase production was readily seen in cultures grown with pine or poplar (100-mesh-size ground wood) as the sole carbon and energy source. Cultures containing both pine and poplar showed 5- to 10-fold-higher levels of laccase than cultures containing pine or poplar alone. Since syringyl units are structural components important in poplar lignin and other hardwoods but much less so in pine lignin and other softwoods, pine cultures were supplemented with syringic acid, and this resulted in laccase levels comparable to those seen in pine-plus-poplar cultures. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of concentrated extracellular culture fluid from HN cultures showed two laccase activity bands (M(r) of 40,000 and 66, 000), whereas isoelectric focusing revealed five major laccase activity bands with estimated pIs of 3.0, 4.25, 4.5, 4.8, and 5.1. Low levels of MnP activity ( approximately 100 U/liter) were detected in poplar-grown cultures but not in cultures grown with pine, with pine plus syringic acid, or in HN medium. No LiP activity was seen in any of the media tested; however, probing the genomic DNA with the LiP cDNA (CLG4) from the white rot fungus Phanerochaete chrysosporium showed distinct hybridization bands suggesting the presence of lip-like sequences in G. lucidum.

Basidiomycota↗
PubMed2002

Absorption and metabolism of antioxidative polyphenolic compounds in red wine.

We have shown that drinking red wine reduces oxidation of LDL. This reduction in oxidation has been attributed to the polyphenolic compounds in red wine, but the mechanisms of absorption and metabolism of these compounds has been unclear. We therefore investigated the absorption and metabolism of polyphenols using rats to identify their active forms in biological fluids. We also investigated the effect of tartaric acid (TA), a major organic acid in wine, on the absorption of polyphenols. Our results suggested that low molecular weight polyphenols are absorbed in the intestine and metabolized to their glucuronide conjugates, which exhibit antioxidative activity in plasma, and that TA can enhance the bioavailability of wine polyphenols.

Absorption↗
PubMed1999

Prostaglandin D2 induces interleukin-6 synthesis via Ca2+ mobilization in osteoblasts: regulation by protein kinase C.

We previously showed that prostaglandin (PG) D2 stimulates Ca2+ influx from extracellular space and activates phosphoinositidic (PI)-hydrolyzing phospholipase C and phosphatidylcholine (PC)-hydrolyzing phospholipase D independently from PGE2 or PGF2alpha in osteoblast-like MC3T3-E1 cells. In the present study, we investigated the effect of PGD2 on the synthesis of interleukin-6 (IL-6) and its regulatory mechanism in MC3T3-E1 cells. PGD2 significantly stimulated IL-6 synthesis dose-dependently in the range between 10 nM and 10 microM. The depletion of extracellular Ca2+ by EGTA reduced the PGD2-induced IL-6 synthesis. TMB-8, an inhibitor of intracellular Ca2+ mobilization, significantly inhibited the PGD2-induced IL-6 synthesis. On the other hand, calphostin C, a specific inhibitor of protein kinase C (PKC), enhanced the synthesis of IL-6 induced by PGD2. In addition, U-73122, an inhibitor of phospholipase C, and propranolol, a phosphatidic acid phosphohydrolase inhibitor, enhanced the PGD2-induced IL-6 synthesis. These results strongly suggest that PGD2 stimulates IL-6 synthesis through intracellular Ca2+ mobilization in osteoblasts, and that the PKC activation by PGD2 itself regulates the over-synthesis of IL-6.

Animals↗
PubMed1997

Basic fibroblast growth factor induces interleukin-6 synthesis in osteoblasts: autoregulation by protein kinase C.

We previously reported that basic fibroblast growth factor (bFGF) stimulates both phospholipases C and D via independent pathways in osteoblastlike MC3T3-E1 cells. In this study, we investigated the effect of bFGF on interleukin-6 (IL-6) synthesis in these cells. bFGF stimulated the IL-6 synthesis dose-dependently in the range between 1 and 30 ng/ml. The depletion of extracellular Ca2+ by EGTA suppressed the bFGF-induced IL-6 synthesis. TMB-8, an inhibitor of intracellular Ca2+ mobilization, also inhibited the IL-6 synthesis by bFGF. bFGF stimulated the Ca2+ influx from extracellular space. Genistein, a tyrosine kinase inhibitor, suppressed the bFGF-induced Ca2+ influx. Staurosporine, an inhibitor for protein kinases, enhanced the bFGF-induced IL-6 synthesis. Calphostin C, a highly potent and specific inhibitor for protein kinase C (PKC), also enhanced the IL-6 synthesis by bFGF. The bFGF-induced IL-6 synthesis was amplified in PKC down-regulated cells. U-73122, a phospholipase C inhibitor, enhanced the bFGF-induced IL-6 synthesis. Propranolol, a phosphatidic acid phosphohydrolase inhibitor, also enhanced the IL-6 synthesis by bFGF. These results strongly suggest that bFGF stimulates IL-6 synthesis, which depends on intracellular Ca2+ mobilization in osteoblastlike cells, and that the IL-6 synthesis by bFGF is autoregulated due to PKC activation.

Animals↗
PubMed2003

Differential regulation of genes encoding manganese peroxidase (MnP) in the basidiomycete Ceriporiopsis subvermispora.

We previously identified and characterized three mnp genes coding for manganese peroxidase (MnP) in the white rot fungus Ceriporiopsis subvermispora. In this work, we assessed transcript levels of mnp genes in liquid cultures of this fungus grown under various conditions. In the absence of Mn(2+), mnp1 and mnp2 mRNA were detected by Northern hybridization, irrespective of the lack of extracellular MnP activity. Addition of Mn(2+) to the cultures led to a marked increase in both transcripts, the highest titers being observed at 10 micro M Mn(2+). mnp1 mRNA was not detected at Mn(2+ )concentrations above 80 micro M, whereas mnp2 mRNA was still observed at 320 micro M Mn(2+). Differential regulation of these genes was confirmed by the addition of Cu(2+), Zn(2+), Ag(+) and Cd(2+). These metal ions dramatically elevated both transcripts and also allowed the detection of the mnp3 transcript. In most cases, the increase in mRNA levels was partially abolished by the simultaneous presence of Mn(2+), although the latter was strictly required to detect extracellular MnP activity. However, the lignin-related compound syringic acid specifically increased the mnp1 transcript, although only in the absence of Mn(2+). These results indicate that there is no clear correlation between mnp mRNA levels and MnP activity. In addition, they strongly suggest that Mn(2+) plays a post-transcriptional role which is essential for the presence of active MnP in the extracellular fluid.

Gallic Acid↗
PubMed2005

The South African and Namibian populations of the resurrection plant Myrothamnus flabellifolius are genetically distinct and display variation in their galloylquinic acid composition.

The polyphenol contents and compositions in desiccated leaves of Myrothamnus flabellifolius plants collected in various locations in Namibia and South Africa were analyzed using UV spectroscopy and high-performance liquid chromatography-mass spectrometry. A study of the genetic relatedness of these populations was also performed by determination of the DNA sequence of the intergenic spacer region between the psbA and the trnH genes in the chloroplast genome. Namibian M. flabellifolius plants contained significantly more polyphenols than South African plants. Namibian plants essentially contained a single polyphenol, 3,4,5-tri-O-galloylquinic acid, whereas South African plants contained a variety of galloylquinic acids including 3,4,5-tri-O-galloylquinic acid together with higher molecular weight galloylquinic acids. Sequence analysis revealed a 1.4% divergence between Namibian and South African plants corresponding to the separation of these populations of approximately 4 x 10(6) years. The significance of the poly-phenol content and composition to the desiccation tolerance of the two populations is discussed.

Base Sequence↗
PubMed1975

Studies on mode of antagonism between adrenergic beta-mimetics and beta-blocking agents (I). Beta-blocking action of mescaline and its derivatives.

In order to clarify whether or not trimetoquinol (TMQ) and isoproterenol (ISO) interact with the same receptor, the pA2 values of propranolol (PR) and certain trimethoxybenzene derivatives were measured, using isolated guinea pig tracheal chains. Each of PR, mescaline (MES) and its derivatives gave almost the same pA2 values for TMQ and ISO. Introduction of an alkyl group into the N atom of MES increased the affinity to the receptor in the order of methyl and isopropyl as well as the structureactivity relationship of catecholamines, while that of hydroxyl group in the beta-position of the side chain decreased pA2 values. The slopes of the regression lines for anti-TMQ action of MES derivatives as well as PR were almost one, but those for their anti-ISO action were less than 0.3. 3,4,5-Trimethoxyaniline and 3,4,5-trimethoxybenzoic acid had little activity as beta-blocking agents. These results suggest the possibility that TMQ and ISO would interact with the same receptor sites. The importance of the trimethoxybenzene and the phenethylamine moieties in the MES-derivatives for anti-TMQ action is discussed.

Adrenergic beta-Agonists↗
PubMed1991

Distinct patterns of chemotactic peptide-induced calcium mobilization in differentiated myeloid leukemia cells and peripheral blood neutrophils.

Flow cytometry was used to compare intracellular calcium mobilization in mature neutrophilic granulocytes (PMN) with HL-60 promyelocytic leukemia cells induced to differentiate with dibutyryl cyclic adenosine 3',5'-monophosphate (dbcAMP). Using the calcium-specific probe indo-1 acetoxymethyl ester, we found that the ability of differentiating HL-60 cells to mobilize calcium in response to N-formyl-methionyl-leucyl-phenylalanine (fMLP) developed concomitantly with expression of receptors on the cells for this peptide. Mobilization of calcium in HL-60 cells, as well as in PMN, in response to fMLP was dose dependent and was related to the presence of calcium in the culture medium. In calcium-free medium, tenfold higher concentrations of fMLP were required to induce calcium mobilization than in calcium-containing medium. In HL-60 cells, calcium mobilization occurred more rapidly than in PMN and was independent of extracellular calcium. Furthermore, the response of HL-60 cells to fMLP was more prolonged than the response of PMN and was also of greater magnitude. Calcium mobilization in both HL-60 cells and PMN was partially inhibited by the calcium channel blocker, verapamil, but completely blocked by trimethylbenzoic acid 8-(diethylamino) octyl ester, an intracellular calcium antagonist. These results indicate that although both cell types mobilize calcium in response to fMLP, the characteristics of the responses are distinct. These differences may underlie distinct functional responses of PMN and differentiated HL-60 cells to fMLP.

Biological Transport, Active↗
PubMed1991

Inhibition of the activation of Hageman factor (factor XII) by human vascular endothelial cell culture supernates.

The supernatant fluid (conditioned medium) of cultured human vascular endothelial cells inhibits activation of Hageman factor (factor XII), whether by ellagic acid, bovine brain sulfatides, or bismuth subgallate; inhibition appears to be a property of one or more proteins in the culture supernates. This phenomenon may contribute to maintaining the fluidity of circulating blood by inhibiting surface activation of the intrinsic pathway of coagulation.

Cells, Cultured↗
PubMed1988

Arginine vasopressin promotes growth of rat glomerular mesangial cells in culture.

Arginine vasopressin (AVP) binds specifically to vascular smooth muscle-like mesangial cells (MCs) and affects contraction. We tested whether this peptide also modulates growth behavior of rat MCs in early subculture (passage 2-5). Subconfluent, serum-starved MCs were exposed to AVP (10(-10)-10(-6) M) in the presence or absence of insulin (5 micrograms/ml). To assess DNA replication, MC uptake of [3H]thymidine (24-h pulse) was determined on days 1, 2, and 3. AVP alone averaged a 1.97-fold increase in DNA synthesis at 24 h, whereas the mean stimulatory effects of AVP at 48 and 72 h were 7.21- and 5.42-fold, respectively. MCs exposed simultaneously to AVP and insulin showed potentiation of the mitogenic response to AVP alone. The V1-receptor antagonist [1-(beta-mercapto-beta,beta-cyclopentamethylene proprionic acid), 2-(O-methyl-Tyr)-Arg]vasopressin (PMP) inhibited only AVP-induced promotion of MC growth (maximal inhibition of -78.3%). The phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA) acutely stimulated MC proliferation but did not add to the AVP effect. Preincubation of MCs with 600 nM of TPA for 48 h significantly inhibited AVP-induced mitogenesis (-87.2%). By use of fura-2, intracellular calcium (Cai) was assessed by spectrofluorometry. The addition of AVP (10(-12)-10(-6) M) led to a rapid, transient, dose-dependent increase in Cai of 154-383%, respectively. The AVP-induced increase in Cai was greatly inhibited by 3,4,5-trimethoxybenzoic acid 8-(diethylamino)octyl ester hydrochloride (TMB-8) (10(-8)-10(-6) M), an inhibitor of Cai release (-23.9 to -72.1%), and it was blunted by the atrial natriuretic peptide AP-28 (-38.3%).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1998

8-(N,N-diethylamino)-n-octyl-3,4,5-trimethoxybenzoate reduced [Ca2+]i elevation induced by histamine, serotonin, and glutamate in cultured calf basilar artery smooth muscle cells.

AIM: To study the effects of 8-(N,N-diethylamino)-n-octyl-3,4,5- trimethoxybenzoate (TMB-8) on intracellular free calcium ([Ca2+]i) in cultured calf basilar artery smooth muscle cells. METHODS: [Ca2+]i was examined by a system of measurement of AR-CM-MIC, using Fura 2-AM as a fluorescent indicator. RESULTS: In the presence of extracellular Ca2+ 1.3 mmol.L-1, histamine (His), serotonin (5-HT), and sodium glutamate (Glu) markedly increased the [Ca2+]i which was attenuated by TMB-8. In Ca2+ free Hanks' solution containing egtazic acid 0.1 mmol.L-1, TMB-8 not only reduced the resting [Ca2+]i, but also inhibited the elevation of [Ca2+]i evoked by His and 5-HT. CONCLUSION: TMB-8 reduced the resting [Ca2+]i and attenuated His-, 5-HT-, and Glu-induced increases of [Ca2+]i in basilar artery smooth muscle cells.

Animals↗
PubMed2002

[Simultaneous determination of five antioxidants in food by HPLC with fluorescence detection].

An HPLC method with fluorescence detection was developed for the determination of propyl gallate, nordihydroguaiaretic acid, butylated hydroxyanisole (2- and 3-tert-butyl-4-hydroxyanisole), tert-butylhydroquinone and octyl gallate in edible oils and foods. The antioxidants in edible oil were isolated directly with acetonitrile saturated with n-hexane. The antioxidants in food were extracted with ethyl acetate and the extract was concentrated under vacuum. They were isolated from the residue with acetonitrile saturated with n-hexane. The acetonitrile layer was centrifuged at 5,000 rpm for 10 min. The HPLC separation was performed on a Symmetry C18 column (3.5 microns, 4.6 mm i.d. x 150 mm) using a mixture of 5% acetic acid-acetonitrile-methanol (4:3:3, v/v/v) as the mobile phase and monitored by using a fluorescence detector with time programming. Sample peaks were identified by comparison of the fluorescence spectra with those of antioxidant standards. Average recoveries of fortified antioxidants at 100 micrograms/g were 72.1-99.6%. Coefficients of variation were 0.7-7.2%.

Antioxidants↗
PubMed2007

Slow-binding inhibition of soybean lipoxygenase-1 by dodecyl gallate.

Dodecyl gallate inhibited the soybean lipoxygenase-1 (EC 1.13.11.12, type-1) catalyzed peroxidation of linoleic acid with an IC50 of 0.007 microM without being oxidized. The progress curves for enzyme reactions were recorded by both spectrophotometric and polarographic methods, and the inhibition kinetics revealed competitive and slow-binding inhibition. Both the initial velocity and steady-state rate in the progress curve decreased with increasing dodecyl gallate. The kinetic parameters that described the inhibition by dodecyl gallate were evaluated by nonlinear regression fits.

Enzyme Inhibitors↗
PubMed1995

Multiple second messenger systems act sequentially to mediate rolipram-induced prolongation of prostaglandin E2-induced mechanical hyperalgesia in the rat.

In this study we have evaluated the mechanisms mediating the prolonged hyperalgesia induced by administration of prostaglandin E2 plus rolipram, an inhibitor of type IV phosphodiesterase. The Randall-Selitto paw pressure device was employed to measure the effect of intradermal injection of test agents on the time course of the decrease in mechanical nociceptive threshold produced by prostaglandin E2 plus rolipram in the hairy skin of the hindpaw of the rat. The intradermal injection of prostaglandin E2 produced a dose-dependent decrease in the nociceptive threshold which lasted approximately 2 h. While rolipram alone had no significant effect on nociceptive threshold, it enhanced and prolonged (> 72 h) prostaglandin E2-induced hyperalgesia. WIPTIDE, a protein kinase A inhibitor, when administered 30 min after prostaglandin E2, or with prostaglandin E2 plus rolipram, a time when prostaglandin E2-induced hyperalgesia was at its peak, produced a significant reduction in hyperalgesia. However, at 90 or at 180 min after injection of prostaglandin E2 plus rolipram, WIPTIDE was found to be without effect. H-8, a protein kinase G inhibitor, and okadaic acid, a protein phosphatase inhibitor, when administered 30 min after prostaglandin E2, or 180 min after prostaglandin E2 plus rolipram, produced no significant effect. However, when administered 90 min after prostaglandin E2 plus rolipram, each produced a significant reduction in the hyperalgesia induced by prostaglandin E2 plus rolipram.(ABSTRACT TRUNCATED AT 250 WORDS)

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed2006

Aqueous chlorination of the antibacterial agent trimethoprim: reaction kinetics and pathways.

Trimethoprim (TMP), one of the antibacterials most frequently detected in municipal wastewaters and surface waters, reacts readily with free available chlorine (i.e., HOCl) at pH values between 3 and 9 (e.g., the pH-dependent apparent second-order rate constant, k''(app)=5.6 x 10(1)M(-1)s(-1), at pH 7). Solution pH significantly affects the rate of TMP reaction with HOCl. The reaction kinetics in reagent water systems can be well described by a second-order kinetic model incorporating speciation of both reactants and accounting for acid-mediated halogenation of TMP's 3,4,5-trimethoxybenzyl moiety. Studies with the substructure model compounds 2,4-diamino-5-methylpyrimidine and 3,4,5-trimethoxytoluene show that TMP reacts with HOCl primarily via its 3,4,5-trimethoxybenzyl moiety at acidic pH, and with its 2,4-diaminopyrimidinyl moiety at circumneutral and alkaline pH. LC/MS product analyses indicate that the TMP structure is not substantially degraded upon reactions with HOCl. Instead, a wide variety of (multi)chlorinated and hydroxylated products are formed. Experiments with real drinking water and wastewater matrixes confirmed that substantial TMP transformation can be expected for conditions typical of wastewater and drinking water chlorination.

Anti-Bacterial Agents↗
PubMed2006

[Chemical constituents in root of Zanthoxylum nitidum].

OBJECTIVE: To study the chemical constituents of Zanthoxylum nitidum. METHOD: Column chromatography on Silica gel and Sephadex LH - 20, and recrystallization were applied for the isolation and purification of the constituents. The structures were elucidated on the basis of spectral analysis, chemical evidences and by comparison with the data reported in literature. RESULT: From the CHCl3 fraction and n-butanol fraction of the EtOH extract of the roots of Z. nitidum, 10 compounds were isolated and identified as 2, 4-dihydroxypyrimidine (1), syringic acid (2) , 2, 6-dimethoxy-1, 4-benzoquinone (3) , 4-hydroxybenzoic acid (4), ethylparaben (5), (Z)-3-(2, 3, 4-trimethoxyphenyl) acrylic acid (6), 5, 6, 7-trimethoxycoumarin (7), stigmast-9 (11) -en-3-ol (8), daucosterol (9), beta-sitosterol (10). CONCLUSION: Compounds 1-9 were isolated and identified from the roots of Z. nitidum for the first time. Furthermore, we note here the first isolation of compound 6 as a natural product.

Acrylates↗