Previous studies have suggested the possibility that the non-steroidal antiflammatory drug (NSAID), ibuprofen, may inhibit thromboxane (TX) A2 synthase activity in addition to inhibiting cyclooxygenase activity. Microsomal fractions isolated from the cat lung contain cyclooxygenase as well as prostacyclin (PGI2) synthase, TX synthase, and a GSH-dependent prostaglandin (PG) E2 isomerase activities. When [1-14C] PG endoperoxide H2 (PGH2) was used as substrate, ibuprofen, indomethacin, and meclofenamate exhibited differential effects on terminal enzyme activities. Ibuprofen, at concentrations up to 1 mM, had no effect on the activities of PGI2 synthase, TXA2 synthase of GSH-dependent PGE2 isomerase, whereas indomethacin selectively inhibited PGI2 synthase activity at 5 X 10(-4) M and 10(-3) M. Meclofenamate selectively inhibited TXA2 synthase activity at 5 X 10(-4) M and 10(-3) M. At concentrations of 5 X 10(-3) M, this selectivity was not observed, and indomethacin and meclofenamate decreased the formation of both 6-keto-PGF1 alpha and TXB2. These data indicate that the choice of NSAID and the concentration employed may specifically alter PGH2 metabolism. This action may affect the physiologic consequences of the exchange of PGH2 between cells. The data further indicate that indomethacin has the potential for use as a tool to specifically attenuate PGI2 synthase activity in vitro.

Incubation of [1-14C]arachidonic acid (AA) and [1-14C]prostaglandin (PG)H2 with rabbit spleen homogenate and microsomes resulted in the formation of a substance with the chromatographic properties of thromboxane (Tx)B2. The radiolabeled material was indistinguishable from authentic TxB2 on TLC in three solvent systems and on radiometric gas chromatography. The generation of TxB2-like material from AA and PGH2 was not observed after boiling of the homogenate and microsomes, and was completely inhibited by imidazole (5 mM). The transformation of AA into the TxB2-like material was not observed during incubation in the presence of indomethacin (28 microM). These results indicate that TxB2 is the principal product of arachidonic acid metabolism by the homogenate or microsomes of rabbit spleen.

Cumulative dose-response curves for histamine induced responses in mesometrial (ME) and antimesometrial (AME) regions of uterine horns isolated from rats at 7th, 16th and 22nd days of pregnancy, were constructed. Histamine inhibited, in dose-related fashion, the isometric developed tension in ME and AME strips obtained at the 7th day of pregnancy, an action antagonized by cimetidine (10(-4)-10(-5) M). On the contrary, at the 16th and 22nd days, histamine (10(-5)-10(-3) M), stimulated spontaneous contractions in the ME region but had no effect in the AME segment. Although histamine and SKF-71481-A2,aH1-receptor agonist, both at 10(-4) M, enhanced similarly ME inotropism at the 16th and at 22nd days of pregnancy, the positive contractile action of histamine was greater at the 16th than at the 22nd day. Moreover, cumulative dose-response curves for histamine and SKF-71481-A2 in the ME region of uteri isolated at the 16th day of gestation, showed that both agonists have approximately the same inotropic potency and efficacy. On the other hand, pyrilamine (at 10(-4) M, but not at 10(-5) M aH1-receptor antagonist, shifted to the right the dose-response curve for histamine in ME strips from uteri at the 16th day of pregnancy and attenuated significantly, the magnitude of the positive inotropism evoked by the amine. Similar findings were observed in the presence of chlorpheniramine (at 10(-6) M), another H1-receptor blocker. In addition, the positive uterine inotropism evoked by histamine in the ME region of preparations isolated at the 16th day of pregnancy, was significantly reduced by an antagonist of phospholipase A2 (mepacrine, 10(-4) M) as well as by acetylsalicylic acid (ASA at 10(-4) M), an inhibitor of cyclooxygenase. Results also indicate that the excitatory uterine inotropism elicited by the agonistic amine in ME strips isolated from rats at the 16th day of pregnancy, was coincident with an enhanced release of prostaglandins (PGs) E2 and F2 alpha, but not of PGE1 and that both augmenting actions of histamine were antagonized by histamine H1 receptor-blockers, namely pyrilamine (mepyramine or chlorpheniramine. Results suggest that histamine at early pregnancy diminished myometrial inotropism via its interaction with H2-receptors, whereas from mid pregnancy up to the moment of parturition it evokes contractile stimulation, most likely due to the activation of H1-receptor located at the mesometrial region of rat uterine horns.(ABSTRACT TRUNCATED AT 400 WORDS)

An isolated fundic mucosal preparation of dog stomach which is capable of exhibiting an alkaline secretion is described. A stable secretion was established 40 min to 1 hr after the mucosa was pretreated with the H2-antagonist cimetidine to block spontaneous acid output. Alkaline secretion decreased when Ca2+ was removed from the nutrient solution. This secretion was stimulated by dibutyryl cyclic GMP, but was not altered by acetylcholine, carbachol, or 16,16-dimethyl PGE2. Alkaline secretion from a similar antral mucosal preparation was stimulated by 16,16-dimethyl PGE2. We conclude that the 16,16-dimethyl PGE2-stimulated bicarbonate secretion previously demonstrated in in vivo canine fundic mucosa is not the result of a direct effect of PG on gastric mucosal cells and that an intact blood circulation or cholinergic innervation is required for this action to occur.

Polyamines such as spermine or putrescine, resulting from increased activity of ornithine decarboxylase (ODC), are known for gastroprotective and mucosal growth promoting effects but little information is available about their role in the acceleration of the healing of stress-induced gastric lesions by epidermal growth factor (EGF). In this study, rats with intact or suppressed ODC activity by alpha-difluoromethylornithine (DFMO, 400 mg/kg i.p.) were subjected to 3.5 h of water immersion and restraint stress (WRS) without or with intragastric (i.g.) administration of spermine and putrescine or with subcutaneous (s.c.) injection of EGF. At 0, 2, 6, 12 and 24 h after stress, rats were killed and the number of gastric lesions was counted, gastric blood flow (GBF) was recorded by the H2-gas clearance technique, the gene expression of ODC mRNA using reverse-transcriptase polymerase chain reaction (RT-PCR) and the ODC activity in this mucosa were determined in oxyntic mucosa. Stress produced gastric lesions combined with decreased GBF (by approximately 43%), but at 2, 6, 12 and 24 h after stress, these lesions and the fall in GBF were gradually attenuated. Healing of stress lesions was accompanied by strong stimulation of ODC mRNA expression and by an immediate increase in enzyme activity, with a peak occurring about 6 h after stress. Pretreatment with DFMO or salivectomy (which resulted in a marked fall in luminal EGF levels and mucosal DNA synthesis) delayed significantly the healing of stress lesions. EGF or spermine significantly accelerated the ulcer healing and raised the GBF. Suppression of endogenous generation of prostaglandins (PGs) with indomethacin (5 mg/kg i.p.) almost completely reversed the EGF- and spermine-induced acceleration of the healing of stress lesions and the accompanying rise in GBF. DFMO significantly reduced the enhancement in healing and the rise in the GBF induced by EGF, but failed to influence those induced by exogenous spermine. The acceleration of the healing induced by spermine or EGF and accompanying hyperemia were not affected by salivectomy. We conclude that (1) upregulation of the ODC transcript, increased ODC activity and polyamines play an important role in mucosal recovery from stress lesions due to acceleration of mucosal repair and an increase in gastric microcirculation, (2) increased ODC activity and resulting excessive polyamine release appear to act as primary mediators of EGF-induced acceleration of healing of stress lesions and (3) endogenous PGs cooperate with EGF and polyamines in mucosal repair from stress ulcerations.

Prostaglandins (PGs) and aluminum-containing antacids (Al.AAs) are effective in preventing gastric and duodenal lesions induced by neutralizing agents. The efficacy of Al.AAs is thought to be due to neutralizing properties and to stimulation of endogenous PGs synthesis. Liquid Maalox has the same effect as cimetidine 400 mg on postprandial duodenal acid load. In numerous prospective studies, Al.AAs have been shown to be as effective as cimetidine in the short-term treatment of duodenal ulcer (DU). Maalox TC at a dosage of 3 tablets b.i.d. provides an effective method for preventing DU relapse. Its effect is similar to that of nighttime cimetidine. Meta-analysis of prospective trials suggests that Al.AAs prevent stress ulcers more effectively than does cimetidine. It has been suggested that Al.AA acts by inducing surface epithelial cell disruption. Al-induced mucosal protection could be caused by a stimulated release of endogenous PGs, induced by Al microcrystal penetration of cells. In a recent study, we showed that small amounts of Al were absorbed by human gastric mucosa and accumulated in lysosomes; however, we did not observe any histological or ultrastructural lesions of the gastric mucosa. Prostaglandins (enprostil, misoprostol, and rioprostil) are as effective as cimetidine, but less effective than ranitidine, in healing DU. Enprostil and rioprostil have been shown to be as effective as ranitidine in treating gastric ulcer (GU). Moreover, enprostil inhibits postprandial gastrin release, whereas H2-blockers increase gastrin levels. Coadministration of misoprostol with aspirin is highly effective in healing aspirin-induced gastroduodenal lesions. Moreover, cotreatment with misoprostol was associated with a marked decrease in GU in patients with osteoarthritis receiving NSAIDs chronically.(ABSTRACT TRUNCATED AT 250 WORDS)

Small infusions of strong acid create large elevations in heart rate (HR), mean arterial pressure (MAP), adrenocorticotropic hormone (ACTH), cortisol, and thromboxane A2 (TxA2). We hypothesized that TxA2 is responsible for these hormonal and hemodynamic responses. Conscious sheep received HCl (1 N, 1 ml/min for 30 min) with or without receiving SQ-29548 [a TxA2/prostaglandin (PG) H2 receptor antagonist]. HCl increased TxB2 from 133 +/- 44 to 1,213 +/- 531 (SE) pg/ml while SQ-29548 + HCl increased TxB2 from 141 +/- 41 to 1,051 +/- 518 pg/ml. HCl decreased pH (7.464 +/- 0.015 to 7.413 +/- 0.011), arterial PCO2 (31.6 +/- 1.3 to 25.9 +/- 1.8 mmHg), and arterial PO2 (98.0 +/- 2.2 to 90.5 +/- 3.2 mmHg), and increased MAP (75 +/- 2 to 88 +/- 5 mmHg), HR (72 +/- 4 to 93 +/- 8 beats/min), hematocrit (25 +/- 1 to 29 +/- 2%), ACTH (154 +/- 41 to 549 +/- 217 pg/ml), and aldosterone (25 +/- 1 to 151 +/- 74 pg/ml) while these responses were prevented by SQ-29548. SQ-29548 reduced but did not prevent the cortisol response to HCl (9 +/- 2 to 23 +/- 10 ng/ml compared with 6 +/- 2 to 17 +/- 4 pg/ml after SQ-29548). K+ and aldosterone also increased after the end of SQ-29548 + HCl treatment (4.0 +/- 0.1 to 4.5 +/- 0.1 meq/l and 53 +/- 21 to 147 +/- 61 pg/ml, respectively). We conclude that TxA2 mediates the blood gas, MAP, HR, ACTH, and aldosterone responses to HCl infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Products of cyclooxygenase activity have been proposed to mediate the pulmonary hypertension and increased microvascular permeability associated with phorbol myristate acetate- (PMA) induced acute lung injury. Previously, we reported that thromboxane (Tx) does not mediate PMA-induced pulmonary hypertension in intact anesthetized dogs. In the present study, PMA was administered to isolated canine lungs perfused with autologous blood at constant flow to investigate a possible role for Tx in the PMA-induced increase in microvascular permeability. Changes in permeability were assessed by determining changes in the capillary filtration coefficient (Kfc). In lobes pretreated with papaverine to prevent PMA-induced increases in pulmonary vascular resistance, Kfc increased from a baseline value of 0.2 +/- 0.03 to 1.5 +/- 0.29 ml.min-1.cmH2O-1.100 g wet lobe wt-1 (P < 0.01) 30 min after PMA (5.8 x 10(-8) M, n = 10). Concomitantly, TxB2, the stable metabolite of TxA2, increased from 138 +/- 44 to 1,498 +/- 505 pg/ml (P < 0.05) in the blood. Both the selective Tx synthase inhibitor, OKY-046 (7 x 10(-4) M, n = 6), and the cyclooxygenase inhibitor, indomethacin (10(-4) M, n = 7), prevented the PMA-induced increase in TxB2, but neither compound attenuated the PMA-induced increase in Kfc. ONO-3708 (10(-6) M), a selective prostaglandin (PG) H2/TxA2 receptor antagonist, prevented the vasoconstriction resulting from administration of U-46619, a stable PGH2/TxA2 receptor agonist, but it did not prevent the PMA-induced increases in Kfc (n = 6).(ABSTRACT TRUNCATED AT 250 WORDS)

A highly sensitive one-step immunocapture EIA for the detection of influenza A virus antigen directly in a clinical specimen was developed. The sensitivity was achieved by using two high-affinity cross-reactive influenza type A-specific monoclonal antibodies, recognizing independent nonoverlapping epitopes on the influenza A nucleoprotein. One of the two MAbs was used as a capture antibody, while the other was coupled with enzyme peroxidase and served as a detector. Sensitivity to detection of highly purified recombinant influenza A virus nucleoprotein by EIA reached approximately 10 pg. Fifteen purified human influenza A virus strains of H1, H2 and H3 subtypes, isolated during the period 1934-1992, were tested by this system. All the influenza A viruses tested positive, whereas two influenza B viruses used as a control were negative. The efficiency of the system for detection of influenza A viral antigen directly in clinical specimens was confirmed by testing nasal and nasopharyngeal washes and aspirates, tested previously by time-resolved fluoroimmunoassay and by virus culture confirmation assay.

A Gram-staining-positive, motile, rod-shaped, aerobic bacterial strain FJAT-25496 ^T was isolated from a forest soil sample collected from Dafu County, Chengdu City, Sichuan Province, China. Strain FJAT-25496 ^T grew at 15-50 °C (optimum 35 °C), pH 6.0-10.0 (optimum 8.0), and NaCl tolerance of 0-4.0% (w/v) (optimum 0%). The strain contained iso-C_15:0 and anteiso-C_15:0 as the predominant cellular fatty acids as well as MK-7 as the only menaquinone. The major polar lipids were diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), and phosphatidyl glycerol (PG). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain FJAT-25496 ^T was a member of the genus Bacillus, and most closely related to Bacillus solani FJAT-18043 ^T (97.8%), Bacillus praedii FJAT-25547 ^T (97.8%), Bacillus depressus BZ1^T (97.7%), Bacillus oceanisediminis H2^T (97.7%), and Bacillus ciccensis 5L6^T (97.6%). Based on complete genome comparisons between strain FJAT-25496 ^T and the type strains of its closely related species, the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values were 73.4-76.3% and 21.7-23.2%, respectively. The genomic DNA G + C content of strain FJAT-25496 ^T was 36.9%. On the basis of phenotypic, phylogenetic, chemotaxonomic, and genomic features, strain FJAT-25496 ^T is considered to represent a novel species of the genus Bacillus, for which the name Bacillus dafuensis sp. nov. is proposed. The type strain is FJAT-25496 ^T (= CCTCC AB 2019182 ^T = KCTC 43120 ^T).

An enzyme-free fluorometric assay is described for the determination of zearalenone (ZEN). The method combines (a) catalyzed hairpin assembly (CHA), (b) ultrahigh fluorescent light-up G-rich DNA sequences in proximity to silver nanoclusters (Ag NCs), and (c) the use of aptamers (Apt). In the presence of ZEN, the inhibit sequence (Inh) is released from the aptamer-trigger sequence (Apt-T) via the binding of ZEN and the aptamer of Apt-T. The free Apt-T acts as a switch that opens the hairpins H1 and H2 to generate H1-H2 complex. The released Apt-T is available to trigger the next round of CHA between H1 and H2. Finally, the hybridization between H1 and the Ag NCs probe (P) causes the G-rich sequence to be in close proximity to the dark Ag NCs encapsulated by P. This leads to highly efficient lighting up of the Ag NCs and the production of amplified fluorescence with excitation/emission peaks at 575/628 nm. Under the optimized conditions, a linear correlation was observed with concentrations ranging from 1.3 pg mL^-1 to 100 ng mL^-1, and the limit of detection was 0.32 pg mL^-1 (at S/N = 3). The method was successfully validated by analyzing maize and beer for levels of ZEN after a simple sample preparation procedure. Graphical abstractSchematic of the assay. The inhibit sequence (Inh) is released from aptamer-trigger sequence (Apt-T) via binding of ZEN and aptamer. The free Apt-T triggers catalyzed hairpin assembly (CHA).G-rich DNA is in proximity to silver nanoclusters (Ag NCs) and fluorescence intensity increases to detect ZEN.

OBJECTIVE

To observe the changes in heme oxygenase-1 (HO-1) expression in lung tissue with ventilator induced lung injury (VILI) in rats, and to explore the mechanism of preventive effect of HO-1 inducer hemin on VILI.

METHODS

Fifty-six male Sprague-Dawley (SD) rats were randomly divided into control group (group C), VILI model group (group M), hemin group 1, 2, 3, 4 (group H1, H2, H3, H4, with intraperitoneal injection of hemin 40, 80, 120, 160 micromol/kg, respectively, 24 hours before model was reproduced), and suppressor Z group (intraperitoneal injection of ZnPP 10 micromol/kg 24 hours before reproduction of the model). After 4 hours of ventilation, all rats, except those of group C, were sacrificed, and bronchoalveolar lavage fluid (BALF) was collected. Total protein, the contents of tumor necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10) in BALF were measured. The lung tissue specimen was collected, the wet-to-dry weight ratio (W/D), the level of lactate dehydrogenase (LDH), superoxide dismutase (SOD), malondialdehyde (MDA) and HO-1 protein expression were determined. Lung pathological changes were observed with microscope.

RESULTS

In group M, rat lung tissue was seriously damaged, and total protein in BALF, TNF-alpha, IL-10, W/D of lung, MDA and LDH activity, as well as HO-1 protein expression were markedly higher than those in group C, denoting that VILI model was successfully reproduced. Compared with group M, the total protein in BALF (g/L) in group H1, H2, H3 was gradually reduced (0.74+/-0.06, 0.73+/-0.07, 0.70+/-0.07 vs. 0.84+/-0.08, all P<0.01) with an increase in hemin dose. W/D of lung was reduced (4.93+/-0.27, 4.91+/-0.24, 4.87+/-0.23 vs. 5.53+/-0.48, all P<0.01). The activity of SOD (U/mg) was higher (85+/-9, 82+/-15, 93+/-11 vs. 55+/-12, all P<0.01), and the content of MDA (nmol/mg) was decreased (15+/-3, 15+/-3, 13+/-2 vs. 18+/-4, P<0.05 or P<0.01). The content of IL-10 (pg/L) in BALF was higher (0.42+/-0.06, 0.46+/-0.06, 0.47+/-0.05 vs. 0.36+/-0.07), and the content of TNF-alpha (pg/L) was decreased (0.18+/-0.07, 0.14+/-0.03, 0.10+/-0.07 vs. 0.23+/-0.06), but only the difference between group H2, H3 and group M was statistically significant (all P<0.01). The activity of LDH (U/g) was decreased (11 353+/-1 317, 11 516+/-1 613, 9 631+/-1 520 vs. 12 361+/-1 841), but only the difference between group H3 and group M was statistically significant (P<0.01). HO-1 expression [absorbance (A) value] was increased compared with that of group M (0.164+/-0.010, 0.190+/-0.149, 0.205+/- 0.018 vs. 0.122+/-0.016, all P<0.01), and the degree of lung injury was reduced with increase in dosage. With the further increase of hemin dose, lung injury in group H4 was more serious than that of group H1, H2 and H3. With ZnPP to inhibit HO-1 expression, the protective effect of HO-1 disappeared.

CONCLUSIONS

A moderate expression of HO-1 as induced by hemin can alleviate VILI, and the best dose of hemin is 120 micromol/kg. Its protective effect on lung tissue may possibly be attributed by its anti-inflammatory effect and anti-oxidative stress.

Inhibition of nitric oxide (NO) synthesis results in coronary vasoconstriction. Using a Langendorff rat heart preparation, we tested the hypothesis that this vasoconstriction is caused by the unopposed effect of the autacoids prostaglandin H2 (PGH2) or thromboxane A2 (TxA2) or both through a mechanism that involves oxygen free radicals. The vasoconstriction induced by NO synthesis inhibition was studied with two different NO synthase inhibitors, N(omega)-nitro-L-arginine methyl ester (L-NAME) and N(omega)-monomethyl-L-arginine (L-NMMA). We found that the decrease in coronary flow (CF) induced by L-NAME (from 19.3 +/- 0.9 to 13.2 +/- 0.9 ml/min; p < 0.001) and L-NMMA (from 20.1 +/- 0.4 to 15.0 +/- 0.3 ml/min; p < 0.001) was completely blocked by the cyclooxygenase inhibitor indomethacin. A different cyclooxygenase inhibitor (ibuprofen), a PGH2/TxA2-receptor antagonist (SQ29548), and a TxA2 synthase inhibitor (CGS 13080) also completely abolished the vasoconstrictor effect of L-NAME, suggesting that this vasoconstriction is mediated by TxA2. Two different scavengers of superoxide radical anions (O2-), the enzyme superoxide dismutase (SOD) and a cell-permeable SOD mimic, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (Tempol), also blocked the vasoconstriction induced by NO synthesis inhibition. In contrast, catalase, which inactivates hydrogen peroxide (H2O2), failed to do so, indicating that O2- is needed for the vasoconstrictor effect of L-NAME, whereas H2O2 is not. To determine whether O2- acts on the conversion of PGH2 to TxA2 or at the receptor or postreceptor level, we studied whether the vasoconstriction induced by exogenous PGH2 or the TxA2 receptor agonist U46619 is blocked by scavengers of O2-. CF decreased by 50% with PGH2 (from 21 +/- 2.1 to 10.6 +/- 5.8 ml/min; p < 0.01), and this decrease was abolished by SOD and Tempol but not catalase. However, SOD had no effect on the vasoconstriction induced by U46619, which decreased CF by 45% (from 17.3 +/- 2.5 to 9.5 +/- 1.8 ml/min; p < 0.01). In addition, PGH2 increased the release of TxB2 (the stable metabolite of TxA2) in the coronary effluent (from 5.1 +/- 1.2 to 136.1 +/- 11.8 pg/ml/min). The release of TxB2 was significantly lower in hearts treated with SOD (76.8 +/- 14.2 pg/ml/min) and CGS (65.7 +/- 13.9 pg/ml/min). We conclude that the coronary vasoconstriction induced by inhibition of NO synthesis is the result of the unopposed effect of the autacoid TxA2 through activation of its receptor, and that O2- is necessary for conversion of PGH2 to TxA2.

The gas-adsorption behaviors of small molecules CO, H2O, H2S, NH3, SO2, and NO on pristine penta-graphene (PG) were investigated using first-principles calculations to explore their potential for use as advanced gas-sensing materials. Results show that, except for CO, H2O, H2S, NH3, and SO2 are physically adsorbed on the surface of penta-graphene with considerable adsorption energy and moderate charge transfer, while NO is prone to be chemically adsorbed on the surface of penta-graphene. Moreover, the electronic properties of PG can be effectively modified after H2O, H2S, NH3, SO2, and NO are adsorbed, and penta-graphene has potential for using in gas sensors via the charge-transfer mechanism.

The effect of a number of anti-tumour agents on prostaglandin (PG) production from arachidonate by sheep seminal vesicles has been investigated. Of the drugs examined only those belonging to the alkylating agent type series showed inhibition of enzyme activity. Unlike most inhibitors of PG synthetase (EC 1.14.99.1) these agents caused an inhibition of prostaglandin E2 (PGE2) production, while unaffecting the formation of prostaglandin F 2alpha (PGF2 alpha). This suggests the site of inhibition is the isomerase converting prostaglandin H2 (PGH2) to PGE2. Kinetic studies indicated that merophan [DL-o-micron-(di-2-chloroethylamino)phenylalanine] inhibited the synthetase competitively with respect to substrate. The kinetics of the inhibition were also consistent with the formation of a reversible enzyme-alkylating agent complex prior to irreversible inactivation of the enzyme. The inactivation process could be described by the Main equation from which a dissociation constant (Kd) and a reaction rate constant (k2) were calculated. The inhibition of PG synthetase may be important in the anti-tumour effect of these agents.

Previously we reported that tumor-promoting phorbol esters stimulate phospholipase D (PLD) independent of protein kinase C (PKC) activation in bovine lymph node lymphocytes. (Cao et al., Biochem. Biophys. Res. Commun. 171, 955-962, 1990; 217, 908-915, 1995). In the present study, we examined the effects of prostagladins (PGs), E2, F2 alpha, D2, and H2 on PLD activity as measured by conversion of [1-14C] arachidonic acid-labeled phospholipids into phosphatidylethanol (PEt) in bovine lymph node lymphocytes. Prostaglandins stimulated the formation of PEt at an optimal concentration of 10 microM with relative stimulatory effect on the order of PGE2>> PGF2 alpha>> PGH2>> PGD2. The PGE2-stimulated formation of PEt was dose-dependent in the range of 0.1 to 10 microM and was not inhibited by PKC inhibitors staurosporine and K252a. When both PGE2 and 12-0-tetradecanoylphorbol-13-acetate (TPA) were included, their effect on the PLD activation was additive. Furthermore, NaF, a G-protein activator, stimulated the PEt formation. Interestingly, the stimulatory effects of PGE2 and NaF were not additive; however, the formation of PEt by NaF and TPA was additive. These results suggest that similar to TPA, PGs increase PLD activity independent of PKC and the stimulation by PGs and TPA in lymphocytes may involve both G-protein-dependent and G-protein-independent signaling pathways.

A novel actinomycete, designated strain NEAU-Jh2-17(T), was isolated from muddy soil collected from a riverbank in Jilin Province, northern China, and characterized using a polyphasic approach. The 16S rRNA gene sequence of strain NEAU-Jh2-17(T) showed highest similarity to those of Streptomonospora nanhaiensis 12A09(T) (99.26%), Nocardiopsis rosea YIM 90094(T) (97.31%), Streptomonospora halophila YIM 91355(T )(97.24%) and Streptomonospora arabica S186(T) (97.02%). Phylogenetic analysis based on 16S rRNA gene sequences demonstrated that strain NEAU-Jh2-17(T) fell within a cluster consisting of the type strains of species of the genus Streptomonospora and formed a stable clade with S. nanhaiensis 12A09(T) in trees generated with two algorithms. Key morphological and chemotaxonomic properties also confirmed the affiliation of strain NEAU-Jh2-17(T) to the genus Streptomonospora. The cell wall contained meso-diaminopimelic acid as the diagnostic diamino acid and whole-cell hydrolysates contained glucose, ribose and galactose. The polar lipids were diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), phosphatidylcholine (PC), phosphatidylinositol (PI), phosphatidylinositol mannoside (PIM), two unknown phospholipids (PLs) and two unknown glycolipids (GLs). The predominant menaquinones were MK-10(H2), MK-10(H8), MK-10(H6) and MK-10(H4). Major fatty acids were C18 : 0 10-methyl, anteiso-C17 : 0, C16 : 0 10-methyl, iso-C15 : 0, C17 : 0 10-methyl and C18 : 0. The DNA G+C content was 71.82 mol%. However, a combination of DNA-DNA hybridization results and some phenotypic characteristics demonstrated that strain NEAU-Jh2-17(T) could be distinguished from its closely related relatives. Therefore, strain NEAU-Jh2-17(T) is considered to represent a novel species of the genus Streptomonospora, for which the name Streptomonospora halotolerans sp. nov. is proposed. The type strain is NEAU-Jh2-17(T) ( = CGMCC 4.7218(T) = JCM 30347(T)).

In this study, we firstly propose a novel smartphone-assisted visualization SNP genotyping method termed competitive activation cross amplification (CACA). The mutation detection strategy depends on the ingenious design of both a start primer and a verification probe with ribonucleotide insertion through competitive combination and perfect matching with the target DNA, Meanwhile, the RNase H2 enzyme was utilized to specifically cleave ribonucleotide insertion and achieve extremely specific dual verification. Simultaneously, the results allow both colorimetric and fluorescence product dual-mode visualization by using self-designed 3D-printed dual function cassette. We validated this novel CACA by analyzing the Salmonella Pullorum rfbS gene at the 237th site, successfully solve the current bottleneck of specific identification and visual detection of this pathogen. The concentration detection limits of the plasmid and genomic DNA were 1500 copies/μL and 3.98 pg/μL, respectively, and as low as the presence of 0.1% mutant-type can be distinguished from 99.9% wild-type. Combined with a powerful hand-warmer, which can provide heating more than 60 °C for 20 h to realize power-free, dual function cassette and smartphone quantitation, our novel CACA platform firstly realizes user-friendly, cost-effective, portable, rapid, and accurate POC detection of SNP.

Keywords: Competitive activation cross amplification; Point-of-care testing; RNase H2 enzyme; Single nucleotide polymorphism; Smartphone.

Sonoluminescence spectra in relation with sonochemical activity of water sparged with Ar/N2 gas mixtures were systematically studied at two ultrasonic frequencies (20 and 359 kHz). At 20 kHz, solely the molecular emission of OH (A(2)Σ(+)-X(2)Πi) is observed in addition to a broad continuum typical for multibubble sonoluminescence. On the contrary, at high frequency a second emission band is present around 336 nm which is assigned to the NH (A(3)Π-X(3)Σ(-)) system. In addition, the sonolysis of a 0.2 M NH3·H2O solution at 359 kHz in the presence of pure Ar yields the emission bands of NH (A(3)Π - X(3)Σ(-)) (336 nm) and NH (C(1)Π-A(1)Δ) (322 nm) systems confirming the sonochemical production of NH radicals. The N2 (C(3)Πu-B(3)Πg) emission band is absent at both frequencies. This uncommon phenomenon can be explained by the quenching of the N2 (C(3)Πu) excited state with water molecules inside the bubbles. The sonoluminescence of NH radicals at 359 kHz indicates more effective intrabubble dissociation of N2 molecules at high ultrasonic frequency compared to low-frequency (20 kHz) ultrasound. Its absence at 20 kHz may also be related to strong quenching, e.g., by water molecules. The kinetic study of the formation of principal sonochemical products (H2, H2O2, HNO3, HNO2) confirmed the more drastic conditions produced during bubble collapse at higher ultrasonic frequency.

A novel electrochemical magnetoimmunosensor for fast and ultrasensitive detection of H9N2 avian influenza virus particles (H9N2 AIV) was designed based on the combination of high-efficiency immunomagnetic separation, enzyme catalytic amplification, and the biotin-streptavidin system. The reusable, homemade magneto Au electrode (M-AuE) was designed and used for the direct sensing. Immunocomplex-coated magnetic beads (IMBs) were easily accumulated on the surface of the M-AuE to obtain the catalytically reduced electrochemical signal of H2 O2 after the immunoreaction. The transducer was regenerated through a simple washing procedure, which made it possible to detect all the samples on a single electrode with higher reproducibility. The magnetic-bead-based electrochemical immunosensor showed better analytical performance than the planar-electrode-based immunosensor with the same sandwich construction. Amounts as low as 10 pg mL(-1) H9N2 AIV could be detected even in samples of chicken dung. This electrochemical magnetoimmunosensor not only provides a simple platform for the detection of the virus with high sensitivity, selectivity, and reproducibility but also shows great potential in the early diagnosis of diseases.

Two prostaglandin (PG) H synthases encoded by Ptgs genes, colloquially known as cyclooxygenase (COX)-1 and COX-2, catalyze the formation of PG endoperoxide H2, the precursor of the major prostanoids. To address the functional interchangeability of these two isoforms and their distinct roles, we have generated COX-2>COX-1 mice whereby Ptgs2 is knocked in to the Ptgs1 locus. We then "flipped" Ptgs genes to successfully create the Reversa mouse strain, where knock-in COX-2 is expressed constitutively and knock-in COX-1 is lipopolysaccharide (LPS) inducible. In macrophages, flipping the two Ptgs genes has no obvious impact on COX protein subcellular localization. COX-1 was shown to compensate for PG synthesis at high concentrations of substrate, whereas elevated LPS-induced PG production was only observed for cells expressing endogenous COX-2. Differential tissue-specific patterns of expression of the knock-in proteins were evident. Thus, platelets from COX-2>COX-1 and Reversa mice failed to express knock-in COX-2 and, therefore, thromboxane (Tx) production in vitro and urinary Tx metabolite formation in COX-2>COX-1 and Reversa mice in vivo were substantially decreased relative to WT and COX-1>COX-2 mice. Manipulation of COXs revealed isoform-specific compensatory functions and variable degrees of interchangeability for PG biosynthesis in cells/tissues.

The central and peripheral adrenergic systems are involved in the regulation of gastric secretion but little is known about the role of alpha- and beta-adrenoceptors in gastroprotection. In this study, acute gastric lesions were produced by an intragastric (i.g.) application of 100% ethanol and gastric blood flow (GBF) was determined by H2-gas clearance technique in rats with or without i.g. or intraperitoneal (i.p.) administration of alpha- or beta-adrenoceptor agonists or antagonists. Phenylephrine, alpha1-adrenergic agonist, and clonidine, alpha2-agonist, significantly augmented the ethanol-induced lesions while decreasing the GBF and these effects were reversed by the blockade of alpha1-adrenoceptors with prazosin and alpha2-adrenoceptors with yohimbine. In contrast, isoproterenol (ISO) (0.01-10 mg/kg i.g.), beta-adrenoceptor agonist, reduced dose-dependently ethanol-induced mucosal injury and this effect was accompanied by an elevation of the GBF similarly as after epidermal growth factor (EGF) (100 microg/kg x h s.c.) or after classic protective agent, 16,16-dimethyl-PGE2 (PGE2) (10 microg/kg i.g.). The pretreatment with beta-antagonist, propranolol, diminished the protective and hyperemic effects of ISO and EGF but failed to affect those induced by PGE2. Suppression of nitric oxide (NO) synthase activity by L-NAME or sensory denervation with capsaicin attenuated significantly the ISO- and EGF-induced gastroprotection and elevation of GBF, whereas the inhibition of PG biosynthesis by indomethacin remained without any significant effect. Adrenal medullectomy or chemical sympathectomy by 6-hydroxydopamine by itself failed to influence significantly the ethanol-induced damage but completely abolished the protective and hyperemic effects of EGF being without any influence on those induced by PGE2. ISO combined with EGF, restored the protective and hyperemic effects of this peptide in medullectomized rats. We conclude that (1) local activation of beta-adrenoceptors by ISO affords protection and elevation of GBF, both these effects being mediated by arginine-NO pathway and sensory nerves and (2) sympathetic system and adrenal medulla contribute to the protective and hyperemic activity of EGF.

Herein, a novel signal-on photoelectrochemical (PEC) biosensor with nearly zero background noise (ZBN) was first fabricated to determine the presence of organophosphorus pesticide based on in situ formation of DNA-templated Ag₂S photoactive materials, accompanied by hybridization chain reaction (HCR) signal amplification. The capture probe (S1) on the gold nanoparticle-modified electrode can hybridize with the aptamer molecule to generate a simple PEC biosensor. In the presence of a target molecule, the aptamer molecule is released on the double-stranded DNA (dsDNA)-modified PEC biosensor. Meanwhile, the capture probe remains on the electrode and can open the DNA hairpins (H1, H2) which are rich in cytosine, to trigger the HCR reaction. The rich "C" strands are uncovered after formation of a long dsDNA polymer strand, which can assemble multiple silver ions (Ag⁺) by means of by C-Ag⁺-C chelation. Then, a large number of Ag₂S can be generated by challenging with S^2- solution, producing a satisfactory photocurrent signal. The photoactive material is formed in situ, which eliminates the laborious operation. Moreover, the signal can be highly amplified with nearly zero background noise and HCR signal amplification. Under optimal conditions, the ZBN aptasensor exhibited high sensitivity and selectivity, with a low detection limit of 2 pg mL^-1 for malathion. Importantly, the sensing platform can also be applied to determine the presence of malathion in real samples. In this assay, a novel signal-on photoelectrochemical biosensor with nearly zero background noise was first fabricated to determine the presence of organophosphorus pesticide based on in situ formation of DNA-templated Ag₂S photoactive materials, accompanied by hybridization chain reaction signal amplification.

Keywords: Ag2S; Hybridization chain reaction; Malathion; Photoelectrochemical aptasensor; Zero background.

Theoretical ab initio calculations are reported of the cross sections for dissociative recombination of the lowest four excited vibrational levels of N2(+) at electron energies from 0.001 to 1.0 eV. Rydberg vibrational levels contributing to the cross section structures are identified as are dissociative channels contributing more than 10(-16) cm(2) to the total cross sections. In contrast to the prior study of v = 0 (S. L. Guberman, J. Chem. Phys. 137, 074309 (2012)), which showed 2(3)Πu to be the dominant dissociative channel, 4(3)Πu is dominant for v = 1. Both 2 and 4(3)Πu are major routes for dissociative recombination from v = 2-4. Other routes including 2(3)Σu(+), 3(3)Πu, 2(1)Πu, 2(3)Πg, 2(1)Σg(+), 1(1)Δg, and b('1)Σu(+) are significant in narrow energy ranges. The results show that minor dissociative routes, included here for N2(+), must be included in theoretical studies of other molecular ions (including the simplest ions H2(+) and H3(+)) if cross section agreement is to be found with future high resolution dissociative recombination experiments. The calculated predissociation lifetimes of the Rydberg resonances are used in a detailed comparison to two prior storage ring experiments in order to determine if the prior assumption of isotropic atomic angular distributions at "zero" electron energy is justified. The prior experimental assumption of comparable cross sections for v = 0-3 is shown to be the case at "zero" but not at nonzero electron energies. Circumstances are identified in which indirect recombination may be visualized as a firefly effect.