A Strong Protective Action of Guttiferone-A, a Naturally Occurring Prenylated Benzophenone, Against Iron-Induced Neuronal Cell Damage

Guttiferone-A (GA) is a natural occurring polyisoprenylated benzophenone with several reported pharmacological actions. We have assessed the protective action of GA on iron-induced neuronal cell damage by employing the PC12 cell line and primary culture of rat cortical neurons (PCRCN). A strong protection by GA, assessed by the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carbox-anilide (XTT) assay, was revealed, with IC(50) values <1 mu M. GA also inhibited Fe(3+)-ascorbate reduction, iron-induced oxidative degradation of 2-deoxiribose, and iron-induced lipid peroxidation in rat brain homogenate, as well as stimulated oxygen consumption by Fe(2+) autoxidation. Absorption spectra and cyclic voltammograms of GA Fe(2+)/Fe(3+) complexes suggest the formation of a transient charge transfer complex between Fe(2+) and GA, accelerating Fe(2+) oxidation. The more stable Fe(3+) complex with GA would be unable to participate in Fenton-Haber Weiss-type reactions and the propagation phase of lipid peroxidation. The results show a potential of GA against neuronal diseases associated with iron-induced oxidative stress.

Extracellular alkalinization induces endothelium-derived nitric oxide dependent relaxation in rat thoracic aorta

Aim: To investigate the mechanism through which the extracellular alkalinization promotes relaxation in rat thoracic aorta. Methods: The relaxation response to NaOH-induced extracellular alkalinization (7.4-8.5) was measured in aortic rings pre-contracted with phenylephrine (Phe, 10(-6) M). The vascular reactivity experiments were performed in endothelium-intact and -denuded rings, in the presence or and absence of indomethacin (10(-5) M), NG-nitro-L-arginine methyl ester (L-NAME, 10(-4) M), N-(6-Aminohexyl)-5-chloro-1-naphthalenesulfonamide/HCl (W-7, 10(-7) M), 2,5-dimethylbenzimidazole (DMB, 2 x 10(-5) M) and methyl-B-cyclodextrin (10(-2) M). In addition, the effects of NaOH-induced extracellular alkalinization (pH 8.0 and 8.5) on the intracellular nitric oxide (NO) concentration was evaluated in isolated endothelial cells loaded with diaminofluorescein-FM diacetate (DAF-FM DA, 5 mu M), in the presence and absence of DMB (2 x 10(-5) M). Results: The extracellular alkalinization failed to induce any change in vascular tone in aortic rings pre-contracted with KCl. In rings pre-contracted with Phe, the extracellular alkalinization caused relaxation in the endothelium-intact rings only, and this relaxation was maintained after cyclooxygenase inhibition; completely abolished by the inhibition of nitric oxide synthase (NOS), Ca(2+)/calmodulin and Na(+)/Ca(2+). exchanger (NCX), and partially blunted by the caveolae disassembly. Conclusions: These results suggest that, in rat thoracic aorta, that extracellular alkalinization with NaOH activates the NCX reverse mode of endothelial cells in rat thoracic aorta, thereby the intracellular Ca(2+) concentration and activating the Ca(2+)/calmodulin-dependent NOS. In turn, NO is released promoting relaxation. (C) 2010 Elsevier Inc. All rights reserved.

Photoreactions of n-alkyl-3-nitrophenyl ethers with aromatic amines in SDS micelles: A laser flash photolysis study

The quenching of the triplet state of three n-alkyl 3-nitrophenyl ethers: 3-nitroanisol (3-NA), n-butyl 3-nitrophenyl ether (3-NB) and n-decyl 3-nitrophenyl ether (3-ND) by four aniline derivatives: aniline (AN), N,N-dimethylaniline (DMA), 2,4,6-trimethylaniline (TMA), and 4-tetradecylaniline (TDA), was investigated in aqueous micellar SDS solutions by laser flash photolysis. The transient absorption spectra for 3-NA and 3-NB reveal the formation of long-lived intermediate species in the presence of all four quenchers. while for 3-ND no amine-induced intermediates are observed. Comparison of the transient absorption spectra of the probe 3-NA in the presence of DMA in aqueous and micellar solutions shows that the intermediate species are favored by the SDS micelles. With DMA and TMA as quenchers the intermediates are suggested to be the ion radicals generated by single electron transfer from the amine to the probe in the triplet excited state. For the quenchers AN and TDA, the intermediates may be a-complexes. The relative quenching efficiencies generally decrease as the affinity of the quencher for the micellar phase (AN < DMA < TMA < TDA) increases and the mobility of the excited probe (3-NA > 2-NB) decreases. (C) 2011 Elsevier B.V. All rights reserved.

Relaxation evoked by extracellular Ca(2+) in rat aorta is nerve-independent and involves sarcoplasmic reticulum and L-type Ca(2+) channell

The perivascular nerve network expresses a Ca(2+) receptor that is activated by high extracellular Ca(2+) concentrations and causes vasorelaxation in resistance arteries. We have verified the influence of perivascular nerve fibers on the Ca(2+)-induced relaxation in aortic rings. To test our hypothesis, either pre-contracted aortas isolated from rats after sensory denervation with capsaicin or aortic rings acutely denervated with phenol were stimulated to relax with increasing extracellular Ca(2+) concentration. We also studied the role of the endothelium on the Ca(2+)-induced relaxation, and we verified the participation of endothelial/nonendothelial nitric oxide and cyclooxygenise-arachidonic acid metabolites. Additionally, the role of the sarcoplasmic reticulum, K(+) channels and L-type Ca(2+) channels on the Ca(2+)-induced relaxation were evaluated. We have observed that the Ca(2+)-induced relaxation is completely nerve independent, and it is potentiated by endothelial nitric oxide (NO). In endothelium-denuded aortic rings, indomethacin and AH6809 (PGF(2 alpha) receptor antagonist) enhance the relaxing response to Ca(2+). This relaxation is inhibited by thapsigargin and verapamil, while was not altered by tetraethylammonium. In conclusion, we have shown that perivascular nervous fibers do not participate in the Ca(2+)-induced relaxation, which is potentiated by endothelial NO. In endothelium-denuded preparations, indomethacin and AH6809 enhance the relaxation induced by Ca(2+). The relaxing response to Call was impaired by verapamil and thapsigargin, revealing the importance of L-type Ca(2+) channels and sarcoplasmic reticulum in this response. (c) 2008 Elsevier Inc. All rights reserved.

Molecular characterization of the Aspergillus fumigatus NCS-1 homologue, NcsA

Here, we characterize the Aspergillus homologue ncsA Neuronal Calcium Sensor. We that ncsA is not an essential gene and Delta ncsA growth decreased in the presence of EGTA and SDS. the Delta ncsA mutant is more resistant to calcium NcsA: mRFP localizes to the cytoplasm and its localization is not affected by the cellular response to calcium chloride or EGTA. The Delta ncsA mutant strain more sensitive to voriconazole, itraconazole, and Polar growth in the Delta ncsA mutant was also more aVected by lovastatin than in the wild type The Spitzenkorper can be visualized in both strains although the vacuolar system does not seem to be very different, there is an increase in the staining intensity on the germling surface of the Delta ncsA strain. NcsA promotes pmcA and pmcB expression and therefore there is a reduced expression of these ion pumps in the Delta ncsA mutant background, and also of other genes involved in the response to calcium in A. fumigatus. The ncsA inactivation mutation is not causing loss of virulence in a low dose murine infection when compared to the corresponding wild type strain.

BjussuSP-I: A new thrombin-like enzyme isolated from Bothrops jararacussu snake venom

A thrombin-like enzyme named BjussuSP-I, isolated from B. jararacussu snake venom, is an acidic single chain glycoprotein with approximately 6% sugar, Mr = 61,000 under reducing conditions and pI similar to 3.8, representing 1.09% of the chromatographic A(280) recovery. BjussuSP-I is a glycosylated scrine protease containing both N-linked carbohydrates and sialic acid in its structure. BjussuSP-I showed a high clotting activity upon human plasma, which was inhibited by PMSF, leupeptin, heparin and 1,10-phenantroline. This enzyme showed high stability regarding coagulant activity when analyzed at different temperatures (-70 to 37 degrees C), pHs (4.5 to 8.0), and presence of two divalent metal ions (Ca2+ and Mg2+). It also displayed TAME esterase and proteolytic activities toward natural (fibrinogen and fibrin) and synthetic (BAPNA) substrates, respectively, being also inhibited by PMSF and leupeptin. BjussuSP-I can induce production of polyclonal antibodies able to inhibit its clotting activity, but unable to inhibit its proteolytic activity on fibrinogen. The enzyme also showed crossed immunoreactivity against I I venom samples of Bothrops, I of Crotalus, and I of Calloselasma snakes, in addition of LAAO isolated from B. moojeni venom. It displayed neither hemorrhagic, myotoxic, edema-inducing profiles nor proteolytic activity on casein. BjussuSP-I showed an N-terminal sequence (VLGGDECDfNEHPFLA FLYS) similar to other thrombin-like enzymes from snake venoms. Based on its biochemical, enzymatic and pharmacological characteristics, BjussuSP-I was identified as a new thrombin-like enzyme isoform from Bothrops jararacussu snake venom. (C) 2007 Elsevier Inc. All rights reserved.

Myotoxic phospholipases A(2) isolated from Bothrops brazili snake venom and synthetic peptides derived from their C-terminal region: Cytotoxic effect on microorganism and tumor cells

This paper reports the purification and biochemical/pharmacological characterization of two myotoxic phospholipases A(2) (PLA(2)S) from Bothrops brazili venom, a native snake from Brazil. Both myotoxins (MTX-I and II) were purified by a single chromatographic step on a CM-Sepharose ion-exchange column up to a high purity level, showing M-r similar to 14,000 for the monomer and 28,000 Da for the dimer. The N-terminal and internal peptide amino acid sequences showed similarity with other myotoxic PLA2S from snake venoms, MTX-I belonging to Asp49 PLA(2) class, enzymatically active, and MTX-II to Lys49 PLA(2)S, catalytically inactive. Treatment of MTX-I with BPB and EDTA reduced drastically its PLA(2) and anticoagulant activities, corroborating the importance of residue His48 and Ca2+ ions for the enzymatic catalysis. Both PLA(2)S induced myotoxic activity and dose-time dependent edema similar to other isolated snake venom toxins from Bothrops and Crotalus genus. The results also demonstrated that MTXs and cationic synthetic peptides derived from their 115-129 C-terminal region displayed cytotoxic activity on human T-cell leukemia (JURKAT) lines and microbicidal effects against Escherichia coli, Candida albicans and Leishmania sp. Thus, these PLA(2) proteins and C-terminal synthetic peptides present multifunctional properties that might be of interest in the development of therapeutic strategies against parasites, bacteria and cancer. (C) 2008 Elsevier Inc. All rights reserved.

Use of Carnobacterium maltaromaticum cultures and hydroalcoholic extract of Lippia sidoides Cham. against Listeria monocytogenes in fish model systems

Minimally processed refrigerated ready-to-eat fishes may offer health risk of severe infection to susceptible individuals due to contamination by the psychrotolerant bacterium L monocytogenes. In this work, inhibition of L monocytogenes by a plant extract and lactic acid bacteria (IAB) was studied in model fish systems kept at 5 degrees C for 35 days. For that, fillets of tropical fish ""surubim"" (Pseudoplatystoma sp.) and hydroalcoholic extract of the plant Lippia sidoides Cham. (""alecrim pimenta"") were used. Fish peptone broth (FPB), ""surubim"" broth and ""surubim"" homogenate were inoculated with combinations of L monocytogenes and bacteriocin-producing Carnobacterium maltaromaticum (C2 and A9b(+)) and non bacteriocin-producing C. maltaromaticum (A9b(-)), in the presence or absence of extract of ""alecrim pimenta"" (EAP). In all model systems, monocultures of L monocytogenes and carnobacteria reached final populations >= 10(8) CFU/ml after 35 days, except for L monocytogenes in ""surubim"" homogenate (10(4) CFU/ml). In FPB, EAP alone and combined with cultures of LAB inhibited L monocytogenes but carnobacteria without EAP were only weakly antilisterial. In ""surubim"" broth, EAP alone did not prevent L monocytogenes growth but cultures of carnobacteria combined or not with EAP inhibited L monocytogenes, with more pronounced effect being observed for C maltaromaticum C2, which produced bacteriocin. In ""surubim"" homogenate, EAP alone and combined with cultures of C. maltaromaticum A9b(-) and A9b(+) were strongly inhibitory to L monocytogenes, while C maltaromaticum C2 with EAP caused transient inhibition of L monocytogenes. No significant inhibition of L monocytogenes was observed for carnobacteria in ""surubim"" homogenate without EAP. In conclusion, it was observed that the use of EAP and cultures of carnobacteria have potential to inhibit L monocytogenes in fish systems and the applications should be carefully studied, considering the influence of food matrix. (c) 2011 Elsevier B.V. All rights reserved.

Enzymatic and structural characterization of a basic phospholipase A(2) from the sea anemone Condylactis gigantea

This work aimed at the isolation and structural/functional characterization of a phospholipase A(2) (CgPLA(2)) from the extract of the anemone Condylactis gigantea. CgPLA2 was isolated with a high purity level through three chromatographic steps, showing pT8.6 and molecular weights of 14,500 and 29,000 for the monomer and dimer, respectively. CgPLA2 showed a high catalytic activity upon fluorescent phospholipids inducing no direct hemolytic activity. This enzyme, which is Ca2+-dependent, showed a lower stability against temperature and pH variations when compared with snake venom enzymes. The enzymatic activity was significantly reduced or completely abolished after chemical modification of CgPLA2 with BPB. Its cDNA was then obtained, with 357 base pairs which codified for a mature protein of 119 amino acid residues. A comparative analysis of the primary structure of CgPLA2 revealed 84%, 61%, 43% and 42% similarity to the PLA2s from Adamsia carciniopados, Nematostella vectensis, Vipera russelli russelli and Both raps jararacussu, respectively. (C) 2010 Elsevier Masson SAS. All rights reserved.

MBCNS2 Example Book

MBCNS2 is a small collection of programs for the simulation of transient two-dimensional (or axisymmetric) flows. It is part of the larger collection of compressible flow simulation codes found at http://www.mech.uq.edu.au/cfcfd/. This manual is a collection of example simulations: scripts, results and commentary. It may be convenient for new users of the code to identify an example close to the situation that they wish to model and then adapt the scripts for that example.

A wavelet-based adaptive technique for adsorption problems involving steep gradients

A general, fast wavelet-based adaptive collocation method is formulated for heat and mass transfer problems involving a steep moving profile of the dependent variable. The technique of grid adaptation is based on sparse point representation (SPR). The method is applied and tested for the case of a gas–solid non-catalytic reaction in a porous solid at high Thiele modulus. Accurate and convergent steep profiles are obtained for Thiele modulus as large as 100 for the case of slab and found to match the analytical solution.

High frequency (1000 Hz) tympanometry in normal neonates

The characteristics of high frequency (1000 Hz) acoustic admittance results obtained from normal neonates were described in this study. Participants were 170 healthy neonates (96 boys and 74 girls) aged between 1 and 6 days (mean = 3.26 days, SD = 0.92). Transient evoked otoacoustic emissions (TEOAEs), and 226 Hz and 1000 Hz probe tone tympanograms were obtained from the participants using a Madsen Capella OAE/middle ear analyser. The results showed that of the 170 neonates, 34 were not successfully tested in both ears, 14 failed the TEOAE screen in one or both ears, and 122 (70 boys, 52 girls) passed the TEOAE screen in both ears and also maintained an acceptable probe seal during tympanometry. The 1000 Hz tympanometric data for the 122 neonates (244 ears) showed a single-peaked tympanogram in 225 ears (92.2 %), a flat-sloping tympanogram in 14 ears (5.7 %), a double-peaked tympanogram in 3 ears (1.2 %) and other unusual shapes in 2 ears (0.8 %). There was a significant ear effect, with right ears showing significantly higher mean peak compensated static admittance and tympanometric width, but lower mean acoustic admittance at +200 daPa and gradient than left ears. No significant gender effects or its interaction with ear were found. The normative tympanometric data derived from this cohort may serve as a guide for detecting middle ear dysfunction in neonates.

Dissolution of a solid sphere in an unbounded, stagnant liquid

An exact analytical solution is obtained for the transient dissolution of solid spheres in a diffusion-controlled environment. This result provides a useful reference point for drug testing in humans. The dimensionless solution is expressed in terms of a single parameter, which accounts for solubility, bulk flow, and stagnant fluid composition. A simple, explicit and exact expression was found to predict time-to-complete dissolution (TCD). An approximate solution was also found which tracks the exact case for low solubility conditions.

Effect of ionic strength and clay mineralogy on Na-Ca exchange and the SAR-ESP relationship

The relationship between sodium adsorption ratio (SAR) and exchangeable sodium percentage (ESP) for all soils has traditionally been assumed to be similar to that developed by the United States Salinity Laboratory (USSL) in 1954. However, under certain conditions, this relationship has been shown not to be constant, but to vary with both ionic strength and clay mineralogy. We conducted a detailed experiment to determine the effect of ionic strength on the Na+-Ca2+ exchange of four clay minerals (kaolinite, illite, pyrophyllite, and montmorillonite), with results related to the diffuse double-layer (DDL) model. Clays in which external exchange sites dominated (kaolinite and pyrophyllite) tended to show an overall preference for Na+, with the magnitude of this preference increasing with decreasing ESP. For these external surfaces, increases in ionic strength were found to increase preference for Na+. Although illite (2:1 non-expanding mineral) was expected to be dominated by external surfaces, this clay displayed an overall preference for Ca2+, possibly indicating the opening of quasicrystals and the formation of internal exchange surfaces. For the expanding 2:1 clay, montmorillonite, Na+-Ca2+ exchange varied due to the formation of quasicrystals (and internal exchange surfaces) from individual clay platelets. At small ionic strength and large ESP, the clay platelets dispersed and were dominated by external exchange surfaces (displaying preference for Na+). However, as ionic strength increased and ESP decreased, quasicrystals (and internal exchange surfaces) formed, and preference for Ca2+ increased. Therefore, the relationship between SAR and ESP is not constant and should be determined directly for the soil of interest.

The effects of prepulse-blink reflex trial repetition and prepulse change on blink reflex modification at short and long lead intervals

Prepulse inhibition and facilitation of the blink reflex are said to reflect different responses elicited by the lead stimulus, transient detection and orienting response respectively. Two experiments investigated the effects of trial repetition and lead stimulus change on blink modification. It was hypothesized that these manipulations will affect orienting and thus blink facilitation to a greater extent than they will affect transient detection and thus blink inhibition. In Experiment 1 (N = 64), subjects were trained with a sequence of 12 lead stimulus and 12 blink stimulus alone presentations, and 24 lead stimulus-blink stimulus pairings. Lead interval was 120 ms for 12 of the trials and 2000 ms for the other 12. For half the subjects this sequence was followed by a change in pitch of the lead stimulus. In Experiment 2 (N = 64), subjects were trained with a sequence of 36 blink alone stimuli and 36 lead stimulus-blink stimulus pairings. The lead interval was 120 ms for half the subjects and 2000 ms for the other half. The pitch of the lead stimulus on prestimulus trials 31-33 was changed for half the subjects in each group. In both experiments, the amount of blink inhibition decreased during training whereas the amount of blink facilitation remained unchanged. Lead stimulus change had no effect on blink modification in either experiment although it resulted in enhanced skin conductance responses and greater heart rate deceleration in Experiment 2. The present results are not consistent with the notion that blink facilitation is linked to orienting whereas blink inhibition reflects a transient detection mechanism. (C) 1998 Elsevier Science B.V.