Toxic effects of pentachlorophenol on Lemna minor.
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Araceae↗
Biomedical subjects
Z H Song
Publications and source records attributed to Z H Song.
Distinction of water-soluble constituents between natural and cultured Cordyceps by capillary electrophoresis.
Cordyceps is an expensive traditional Chinese medicine, which has anti-tumor activity and significant effects on the immune system. In Southeast Asia, Cordyceps is commonly sold in capsule form as a health food product. Most of these products are derived from cultured Cordyceps mycelia. Because of the price difference, some manufacturers claim their products are from natural Cordyceps. In order to distinguish among various types of Cordyceps in the market, the profiles of water-soluble constituents derived from different sources of Cordyceps were determined by capillary electrophoresis (CE). Both natural and cultured Cordyceps showed three peak clusters migrated at 5-7, 9-11 and 12-13 min, and the height and resolution of these peak clusters were rather distinct. Peak cluster at 9-11 min was identified as adenosine, guanosine and uridine, and shared a similarity between natural and cultured products. In contrast, the peak cluster at 5-7 min was characteristic of natural Cordyceps, regardless of hosts and sources. By using the peak characteristics of CE profiles of different Cordyceps samples, hierarchical clustering analysis was performed. The result shows that those samples of natural Cordyceps were grouped together distinct from the cultured and commercial products. Thus, the CE profiles could serve as fingerprints for the quality control of Cordyceps.
Agriculture↗
Effects of D3.49A, R3.50A, and A6.34E mutations on ligand binding and activation of the cannabinoid-2 (CB2) receptor.
In several G protein-coupled receptors (GPCRs), the Asp-Arg-Tyr (DRY) motif at the bottom of third transmembrane domain and the amino acid at position 6.34 in the sixth transmembrane domain have been shown to play important roles in signal transduction. In this study, we propose that in the cannabinoid-2 (CB2) receptor, R3.50 in the DRY motif may be crucial for interacting with G proteins, and D3.49 and A6.34 may be important for constraining the receptor in an inactive conformation. To test our hypothesis, R3.50A, D3.49A, and A6.34E mutations of the human CB2 receptor were made by site-directed mutagenesis. These mutant receptors were stably transfected into human embryonic 293 cells, and their ligand binding and signal transduction properties were analyzed. Similar to other GPCRs, R3.50 of the CB2 receptor is crucial for signal transduction. Unlike other GPCRs, D3.49 and A6.34 of the CB2 receptor do not seem to be important for keeping the receptor in an inactive state. Furthermore, D3.49A and A6.34E mutations abolished ligand binding, and all three mutations abolished constitutive activity of the wild-type CB2 receptor.
Adenylyl Cyclases↗
Absence of a conserved proline and presence of a conserved tyrosine in the CB2 cannabinoid receptor are crucial for its function.
A majority (84%) of G protein-coupled receptors have a proline (P5.50) in the middle of the fifth transmembrane domain. However, one of the unique structural features of cannabinoid receptors is the replacement of the conserved P5.50 by a leucine (L5.50). It has been shown that a conserved tyrosine (Y5.58), located at the cytoplasmic side of P5.50, is crucial for the signal transduction of several G protein-coupled receptors. We proposed that the replacement of P5.50 by L5.50 and the presence of the conserved Y5.58 in this context are important for the function of CB2. Mutating L5.50 to a proline abolished ligand binding, whereas mutating Y5.58 to an alanine resulted in a rightward shift of the competition binding curves. Both of these mutations led to a complete loss of the ability of cannabinoid agonists to inhibit forskolin-stimulated cAMP accumulation.
Amino Acid Sequence↗
CB1 cannabinoid receptor-mediated tyrosine phosphorylation of focal adhesion kinase-related non-kinase.
The effect of cannabinoid on the tyrosine phosphorylation of focal adhesion kinase (FAK) and focal adhesion kinase-related non-kinase (FRNK) was investigated in differentiated mouse neuroblastoma N1E-115 cells. HU-210, a potent cannabinoid agonist, elicited a time-dependent enhancement of tyrosine phosphorylation of FRNK, but not FAK. Pretreatment of cells with antisense oligodeoxynucleotide targeting CB1 cannabinoid receptor abolished HU-210-induced FRNK tyrosine phosphorylation. In addition, pretreatment of cells with 8-Br-cAMP also blocked HU-210-induced FRNK tyrosine phosphorylation. These data demonstrated that HU-210 induces FRNK tyrosine phosphorylation by activating G(i)-coupled CB1 cannabinoid receptor in N1E-115 cells. This newly discovered, cannabinoid-induced FRNK tyrosine phosphorylation might be a novel mechanism for cannabinoid-induced functional changes.
8-Bromo Cyclic Adenosine Monophosphate↗
CB1 cannabinoid receptor-mediated neurite remodeling in mouse neuroblastoma N1E-115 cells.
The morphological remodeling of neuronal cells influences neurogenesis and brain functions. We hypothesize that psychoactive and neurotoxic effects of cannabinoids may be mediated, at least in part, by their morphoregulatory activities. In the present study, mouse neuroblastoma N1E-115 cells were used as an in vitro model to investigate cannabinoid-induced neurite remodeling effects and to identify the involvement of cannabinoid receptors in this neurite remodeling process. Using reverse transcription-polymerase chain reaction and immunofluorescence microscopy, the endogenously expressed CB1, but not CB2, cannabinoid receptors were detected in morphologically differentiated N1E-115 cells. Activation of these natively expressed CB1 cannabinoid receptors by cannabinoid agonist HU-210 led to a concentration-dependent inhibition of adenylate cyclase activity. Importantly, HU-210 treatment induced neurite retraction in a concentration-dependent manner. Pretreatment of N1E-115 cells with a CB1 antisense oligodeoxynucleotide (ODN) suppressed HU-210-induced inhibition of forskolin-stimulated cAMP accumulation, indicating that the knocking down of functional CB1 cannabinoid receptor expression was achieved. Antisense ODN pretreatment also abolished HU-210-induced neurite retraction, demonstrating the involvement of CB1 cannabinoid receptors in mediating the neurite remodeling effects of HU-210. In addition, reversing HU-210-induced intracellular cAMP declination by 8-Br-cAMP partially prevented HU-210-induced neurite retraction, indicating the involvement of cAMP-dependent signaling pathways in mediating the neurite remodeling function of CB1 cannabinoid receptors in N1E-115 cells. These data demonstrate that neurite remodeling is a newly discovered function of CB1 cannabinoid receptors. This morphoregulatory function of CB1 cannabinoid receptors might be a new mechanism that mediates the psychoactive and neurotoxic effects of cannabinoids in developing and adult brain.
8-Bromo Cyclic Adenosine Monophosphate↗
Functional roles of the tyrosine within the NP(X)(n)Y motif and the cysteines in the C-terminal juxtamembrane region of the CB2 cannabinoid receptor.
In G protein-coupled receptors, a NP(X)(n)Y motif in the seventh transmembrane domain and cysteine residues in the C-terminal juxtamembrane region are conserved. In the current study, the roles of Y299 within the NPVIY motif and C313 and C320 in the C-terminal juxtamembrane region of the human CB2 cannabinoid receptor were investigated by site-directed mutagenesis. Replacing Y299 with alanine resulted in a complete loss of ligand binding and a severe impairment of cannabinoid-induced inhibition of forskolin-stimulated cAMP accumulation. The C313A and C320A mutations markedly reduced functional coupling to adenylate cyclase, but had no effect on ligand binding and agonist-induced receptor desensitization.
Adenylyl Cyclases↗
Effect of triphenyltin on duckweed Lemna minor.
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Chloroplasts↗
[Separation of echinacoside by reversed-phase preparative high performance liquid chromatography].
Echinacoside, one kind of phenylethanoid glycosides (PhGs), was isolated from the stems of Cistanche tubulosa (Schenk) R. Wight with a series of steps, including solvent extraction, D101 polymer adsorption column separation, Sephadex LH-20 separation, C18 column reversed-phase preparative high performance liquid chromatographic (RP-prep-HPLC) preparation and polyamide thin-layer chromatographic detection. The purity of the product was over 98%. The chemical structure of echinacoside was identified by 1H NMR and 13C NMR. To find out the optimum condition of mobile phase of RP-prep-HPLC, several systems were used in this work. Finally acetonitrile-1% HCOOH water (18:82, V/V) system was found to be the best. On the other hand D101 polymer adsorption column and Sephadex LH-20 were also effective for PhGs separation.
Chromatography, High Pressure Liquid↗
[Metabolic regulation of phenylethanoid glycosides from Herba cistanches in dogs' gastrointestine].
AIM: To study the metabolic process of phenylethanoid glycosides (PhGs) in the gastrointestine of beagle dogs that were administered intragastrially process, and develop some new methods of biopharmacology on the effective position of traditional Chinese medicine. METHODS: High-performance liquid chromatography was used to purify constituents from faeces and analyze relative contents of the three main compounds in the gastrointestinal tract at different times and in the faeces of dogs. Every sample was collected, extracted with methanol and analyzed with integration. RESULTS: Four compounds, based on reference substances, were identified as echinacoside, acteoside, isoacteoside, and 2'-acetylacteoside from extraction of faces of dogs. Quantitative "with HPLC" analysis reveals that variation of ratios of the three main compounds is not distinct when moving in the gastrointestinal tract 7 h, that is quite different from those in faeces, in which the content of echinacoside fell from 48.0% to 16.0%, and acteoside increased from 11.0% to 34.7%. CONCLUSION: PhGs are mainly metabolized in large intestine. Among them, a portion of echinacoside is transformed into aceteoside.
Animals↗
[A chemiluminescence flow sensor for vitamin B1].
AIM: To determine vitamin B1 in pharmaceutical preparations by chemiluminescence (CL) flow sensor. METHODS: When 200 microL of Na3PO4 was passed through an anion exchange column, K3Fe(CN)6 was eluted from the resin and then mixed with the vitamin B1 stream containing NaOH to product CL, by the fast oxidation reaction between vitamin B1 and K3Fe(CN)6 in alkaline solution. RESULTS: The CL emission intensity was correlated with the vitamin B1 concentration in the range 1.0 x 10(-5) to 1.0 x 10(-3) mol.L-1 and the detection limit was 8.0 x 10(-6) mol.L-1 (3 sigma). A complete analysis, including sampling and washing, can be performed within 2 min with a relative standard deviation of less than 4.0%. CONCLUSION: The vitamin B1 flow sensor was stable for over 200 analyses and has been applied successfully to determination of vitamin B1 in pharmaceutical preparations.
Injections↗
Long circulating liposomes encapsulating organophosphorus acid anhydrolase in diisopropylfluorophosphate antagonism.
These studies are focused on antagonizing organophosphorous (OP) intoxications by a new conceptual approach using recombinant enzymes encapsulated within sterically stabilized liposomes to enhance diisopropylfluorophosphate (DFP) degradation. The OP hydrolyzing enzyme, organophosphorous acid anhydrolase (OPAA), encapsulated within the liposomes, was employed either alone or in combination with pralidoxime (2-PAM) and/or atropine. The recombinant OPAA enzyme, from the ALTEROMONAS: strain JD6, has high substrate specificity toward a wide range of OP compounds, e.g., DFP, soman, and sarin. The rate of DFP hydrolysis by liposomes containing OPAA (SL)* was measured by determining the changes in fluoride-ion concentration using a fluoride ion-selective electrode. This enzyme carrier system serves as a biodegradable protective environment for the OP-metabolizing enzyme (OPAA), resulting in an enhanced antidotal protection against the lethal effects of DFP. Free OPAA alone showed some antidotal protection; however, the protection with 2-PAM and/or atropine was greatly enhanced when combined with (SL)*.
Animals↗
Involvement of cannabinoid receptors in the intraocular pressure-lowering effects of WIN55212-2.
It is known that marijuana smoking and administration of natural cannabinoids reduce intraocular pressure. However, it has not been established whether the intraocular pressure-lowering effects of cannabinoids are mediated by cannabinoid receptors. Aminoalkylindoles are a new class of cannabimimetics with structures entirely different from those of natural cannabinoids. WIN55212-2, a prototypic aminoalkylindole, has been shown to bind cannabinoid receptors and to exhibit cannabinoid-like activities. The objective of this study was to determine whether aminoalkylindoles lower intraocular pressure and whether the effects of aminoalkylindoles are mediated by ocular cannabinoid receptors. The intraocular pressure of New Zealand White rabbits was measured with the use of applanation pneumatonography. After the measurement of baseline intraocular pressure, drugs were applied topically and the intraocular pressure was monitored. The topical application of WIN55212-2 significantly reduced intraocular pressure in the treated eyes. The intraocular pressure-lowering effects of WIN55212-2 were time and dose dependent, and the maximal reduction was 4.7 +/- 0.5 mm Hg at a dose of 100 microg. In contrast to treated eyes, the intraocular pressure on the contralateral eyes was not significantly affected. The topical application of WIN55212-3, the enantiomer of WIN55212-2, had no effect on intraocular pressure. Furthermore, the intraocular pressure-lowering effects of WIN55212-2 were significantly reduced by topically administered SR141716A, a selective antagonist for the CB1 cannabinoid receptor. The dose-response curve of WIN55212-2 is shifted parallel to the right by SR141716A. These data demonstrate that like natural cannabinoids, WIN55212-2 also reduces intraocular pressure, and the effects of WIN55212-2 are mediated at least in part by the CB1 cannabinoid receptors in the eye.
Administration, Topical↗
CB1 cannabinoid receptor-mediated cell migration.
Recent studies have suggested that cell migratory responses are often mediated by G(i) protein-coupled receptors. Because it is known that CB1 cannabinoid receptors are coupled to pertussis toxin-sensitive G proteins, we proposed that CB1 may mediate cell migration. To test this hypothesis, modified Boyden chamber assays were used to investigate cell migration mediated by CB1 cannabinoid receptors. HU-210, WIN55212-2, and anandamide, three cannabinoid agonists with distinct chemical structures, induced migration of human embryonic kidney 293 cells stably transfected with human CB1 gene, but not 293 cells transfected with an empty expression vector. These migratory responses were concentration-dependent. The EC(50) values for HU-210, WIN55212-2, and anandamide were 0.19 +/- 0.04, 12. 2 +/- 1.4, and 39.9 +/- 3.7 nM, respectively. The maximal migration index for HU-210, WIN55212-2, and anandamide were 8.9 +/- 1.6, 9.5 +/- 1.6, and 8.8 +/- 1.3, respectively. Pretreating cells with 100 ng/ml pertussis toxin eliminated the cannabinoid agonist-induced cell migration. SR141716A, a selective antagonist for CB1, inhibited the cannabinoid agonist-induced migratory responses in a concentration-dependent manner. Checkerboard analysis demonstrated that anandamide-induced cell migrations are due to chemotaxis as well as chemokinesis. Furthermore, anandamide-induced migratory responses were inhibited, in a concentration-dependent manner, by PD098059, an inhibitor of mitogen-activated protein kinase activation, but not by 8-bromoadenosine-3',5'-cyclic monophosphate, a cell-permeable cAMP analog. These data demonstrate that cannabinoid agonists are able to induce chemotaxis and chemokinesis, and that these migratory responses are mediated by G protein-coupled, CB1 cannabinoid receptors. In addition, these data suggest that activation of mitogen-activated protein kinase plays an important role, whereas inhibition of adenylate cyclase is probably not involved in the cell migration mediated by CB1.
8-Bromo Cyclic Adenosine Monophosphate↗
[Studies on chemical constituents of Cistanche tubulosa (Schenk) R. Wight].
OBJECTIVE: To investigate the chemical constituents of Cistanche tubulosa. METHOD: The chemical constituents were isolated by solvent extraction together with various chromatographic techniques including preparative HPLC. The structures were elucidated on the basis of chemical evidence and spectral data. RESULTS: Four iridoid glycosides, one lignan glycoside and one monoterpenoid were isolated from the 95% ethanol extract from the stem of C. tubulosa and identified as adoxosidic acid(I), 8-epiloganic acid(II), geniposidic acid (III), mussaenosidic acid(IV), (+)-syringaresinol-O-beta-D-gluco pyranoside(V) and 8-hydroxygeraniol(VI). CONCLUSION: Compounds I and VI were isolated from the genus of Cistanche for the first time. Compounds III, IV and V were isolated from this plant for the first time.
Carboxylic Acids↗
Determination of the thermogenesis curves and studies of the thermodynamics and thermokinetics of seed germination.
The thermogenesis curves of the germination of different rice and tree seeds were determined and studied by using a newly constructed microcalorimeter. The thermogenesis curves of the germination of the seeds demonstrate the existence of physiological triphasic patterns, which include imbibition, activation and growth stages in the germination process. The thermodynamics and thermokinetics of the main growth phase of the growth stage in the germination process have been studied. The growth heat effect (deltaH), the growth rate constant (k), the growth inhibitory factor (s) and deceleration rate constant (beta) have been determined and calculated, In addition, the experimental thermokinetic equations of the growth stage in the seed germination process have been established.
Calorimetry↗
Interactions between dibutyl phthalate and aquatic organisms.
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Algorithms↗
The difference between the CB(1) and CB(2) cannabinoid receptors at position 5.46 is crucial for the selectivity of WIN55212-2 for CB(2).
It has been reported that WIN55212-2, a prototypic aminoalkylindole, has higher affinity for CB(2) than for CB(1). To explain the selectivity of WIN55212-2 for CB(2), molecular modeling studies were performed to probe the interacting sites between WIN55212-2 and cannabinoid receptors. In TMH5 the position 5.46 is a Phe in CB(2) versus a Val in CB(1). Docking of WIN55212-2 into the models of CB(1) and CB(2) predicts that F5.46 will result in a greater aromatic stacking of CB(2) with WIN55212-2. Using site-directed mutagenesis, this hypothesis was tested by exchanging the amino acids at position 5.46 between CB(1) and CB(2). Two mutations, including a Phe to Val mutation at the position 5.46 in CB(2) (CB2F5. 46V), and a corresponding Val to Phe mutation at the position 5.46 in CB(1) (CB(1)V5.46F), were made. The mutant receptors were transfected into 293 cells, and stable cell lines expressing similar numbers of receptors as wild-type receptors were chosen for additional ligand binding and cAMP accumulation studies. In ligand- binding assays, the CB(2)F5.46V mutation decreased the affinity of WIN55212-2 for CB(2) by 14-fold. In contrast, the CB(1)V5.46F mutation increased the affinity of WIN55212-2 for CB(1) by 12-fold. However, these mutations did not change the affinity of HU-210, CP-55940, and anandamide for CB(1) and CB(2). In cAMP accumulation assays, the changes in EC(50) values of WIN55212-2 were consistent with the changes in its binding affinity caused by the mutations. These results strongly support the hypothesis that the selectivity of WIN55212-2 for CB(2) over CB(1) is attributable to the change from Val in CB(1) at position 5.46 to Phe in CB(2).
Benzoxazines↗