Flavonas, lignanas e terpeno de Piper umbellata (Piperaceae)

The phytochemical investigation of Piper umbellata leaves yielded nine compounds including one terpenoid glucoside, five flavones (vitexin 2"-O-β-glucopyranoside, apigenin 8-C-β-D-glucopyranoside,orientin 8-C-β-D-glucopyranoside,5-hydroxy-7,3',4'-trimethoxy-flavone and velutin), two lignans (sesamin e dihydrocubebin) and 4-nerolidylcathecol. Excepting 4-nerolidylcathecol, all compounds have not been described from this species yet.

Overview of the taxonomy and of the major secondary metabolites and their biological activities related to human health of the Laurencia complex (Ceramiales, Rhodophyta) from Brazil

In Brazil, the Laurencia complex is represented by twenty taxa: Laurencia s.s. with twelve species, Palisada with four species (including Chondrophycus furcatus now that the proposal of its transference to Palisada is in process), and Osmundea and Yuzurua with two species each. The majority of the Brazilian species of the Laurencia complex have been phylogenetically analyzed by 54 rbcL sequences, including five other Rhodomelacean species as outgroups. The analysis showed that the Laurencia complex is monophyletic with high posterior probability value. The complex was separated into five clades, corresponding to the genera: Chondrophycus, Laurencia, Osmundea, Palisada, and Yuzurua. A bibliographical survey of the terpenoids produced by Brazilian species showed that only six species of Laurencia and five of Palisada (including C. furcatcus) have been submitted to chemical analysis with 48 terpenoids (47 sesquiterpenes and one triterpene) isolated. No diterpenes were found. Of the total, 23 sesquiterpenes belong to the bisabolane class and eighteen to the chamigrene type, whose biochemical precursor is bisabolane, two are derived from lauranes and four are triquinols. Despite the considerable number of known terpenes and their ecological and pharmacological importance, few experimental biological studies have been performed. In this review, only bioactivities related to human health were considered.

A multi-screening approach for marine-derived fungal metabolites and the isolation of cyclodepsipeptides from Beauveria felina

Extracts obtained from 57 marine-derived fungal strains were analyzed by HPLC-PDA, TLC and ¹H NMR. The analyses showed that the growth conditions affected the chemical profile of crude extracts. Furthermore, the majority of fungal strains which produced either bioactive of chemically distinctive crude extracts have been isolated from sediments or marine algae. The chemical investigation of the antimycobacterial and cytotoxic crude extract obtained from two strains of the fungus Beauveria felina have yielded cyclodepsipeptides related to destruxins. The present approach constitutes a valuable tool for the selection of fungal strains that produce chemically interesting or biologically active secondary metabolites.

A new constitutive theory extending Hypoplasticity

The purpose of the present theory is to improve Hypoplasticity, especially in relation to reloading processes. This is done by means of two hypoplastic equations (a classical equation along with a new one containing a so-called mnemonic tensor), a cone in stress space and a criterion defining loading, unloading and reloading. (C) 2010 Elsevier Ltd. All rights reserved.

Constitutive model for long term municipal solid waste mechanical behavior

This paper presents some improvements in the model proposed by Machado et al. [Machado SL, Carvalho MF, Vilar OM. Constitutive model for municipal solid waste. J Geotech Geoenviron Eng ASCE 2002; 128(11):940-51] now considering the influence of biodegradation of organic matter in the mechanical behavior of municipal solid waste. The original framework considers waste as composed of two component groups; fibers and organic paste. The particular laws of behavior are assessed for each component group and then coupled to represent waste behavior. The improvements introduced in this paper take into account the changes in the properties of fibers and mass loss due to organic matter depletion over time. Mass loss is indirectly calculated considering the MSW gas generation potential through a first order decay model. It is shown that as the biodegradation process occurs the proportion of fibers increases, however, they also undergo a degradation process which tends to reduce their ultimate tensile stress and Young modulus. The way these changes influence the behavior of MSW is incorporated in the final framework which captures the main features of the MSW stress-strain behavior under different loading conditions. (C) 2007 Elsevier Ltd. All rights reserved.

Wavelet-Galerkin method for one-dimensional elastoplasticity and damage problems: Constitutive modeling and computational aspects

This work presents an analysis of the wavelet-Galerkin method for one-dimensional elastoplastic-damage problems. Time-stepping algorithm for non-linear dynamics is presented. Numerical treatment of the constitutive models is developed by the use of return-mapping algorithm. For spacial discretization we can use wavelet-Galerkin method instead of standard finite element method. This approach allows to locate singularities. The discrete formulation developed can be applied to the simulation of one-dimensional problems for elastic-plastic-damage models. (C) 2007 Elsevier Inc. All rights reserved.

Scaling of structures subject to impact loads when using a power law constitutive equation

It is well known that structures subjected to dynamic loads do not follow the usual similarity laws when the material is strain rate sensitive. As a consequence, it is not possible to use a scaled model to predict the prototype behaviour. In the present study, this problem is overcome by changing the impact velocity so that the model behaves exactly as the prototype. This exact solution is generated thanks to the use of an exponential constitutive law to infer the dynamic flow stress. Furthermore, it is shown that the adopted procedure does not rely on any previous knowledge of the structure response. Three analytical models are used to analyze the performance of the technique. It is shown that perfect similarity is achieved, regardless of the magnitude of the scaling factor. For the class of material used, the solution outlined has long been sought, inasmuch as it allows perfect similarity for strain rate sensitive structures subject to impact loads. (C) 2009 Elsevier Ltd. All rights reserved.

Recombinant rabies virus glycoprotein synthesis in bioreactor by transfected Drosophila melanogaster S2 cells carrying a constitutive or an inducible promoter

S2 cell populations (S2AcRVGP2K and S2MtRVGP-Hy) were selected after transfection of gene expression vectors carrying the cDNA encoding the rabies virus glycoprotein (RVGP) gene under the control of the constitutive (actin) or inductive (metallothionein) promoters. These cell populations were cultivated in a 1 L bioreactor mimicking a large scale bioprocess. Cell cultures were carried out at 90 rpm and monitored/controlled for temperature (28 degrees C) and dissolved oxygen (10 or 50% air saturation). Cell growth attained similar to 1.5-3 x 10(7) cells/mL after 3-4 clays of cultivation. The constitutive synthesis of RVGP in S2AcRVGP2K cells led to values of 0.76 mu g/10(7) cells at day 4 of culture. The RVGP synthesis in S2MtRVGP-Hy cell fraction increased upon CuSO(4) induction attaining specific productivities of 1.5-2 mu g/10(7) cells at clays 4-5. RVGP values in supernatant as a result of cell lysis were always very low (<0.2 mu g/mL) indicating good integrity of cells in culture. Overall the RVGP productivity was of 1.5-3 mg/L. Our data showed an important influence of dissolved oxygen on RVGP synthesis allowing a higher and sustained productivity by S2MtRVGP-Hy cells when cultivated with a DO of 10% air saturation. The RVGP productivity in bioreactors shown here mirrors those previously observed for T-flasks and shaker bottles and allow the preparation of the large RVGP quantities required for studies of structure and function. (C) 2010 Elsevier B.V. All rights reserved.

Secondary metabolites produced by Propionicimonas sp (ENT-18) induce histological abnormalities in the sclerotia of Sclerotinia sclerotiorum

Sclerotinia sclerotiorum is a highly aggressive pathogen that causes great economic losses, especially in temperate climates. Several biological control agents are available, but actinobacteria have seldom been used to control this fungus. Our objective was to evaluate the efficiency and ultrastructural effects of the secondary metabolites produced by the ant-associated actinobacterium Propionicimonas sp. ENT-18 in controlling the sclerotia of S. sclerotiorum. We demonstrated total inhibition of sclerotia treated with 62.5 mu g/10 mu l of an ethyl acetate extract of compounds produced by ENT-18, and calculated an LC(50) of 1.69 mu g/sclerotia. Histological and ultrastructural analysis indicated that the cells of the treated sclerotia were severely damaged, suggesting direct action of the biomolecule(s) produced by the actinobacterium ENT-18 on the cell structure of the medullae and rind cell wall. This is the first report demonstrating a novel property of Propionicimonas sp.-antifungal activity against S. sclerotiorum.

Changes in the hemolymph and fat body metabolites of Diatraea saccharalis (Fabricius) (Lepidoptera : Crambidae) parasitized by Cotesia flavipes (Cameron) (Hymenoptera : Braconidae)

The koinobiont Cotesia flavipes responds to and is influenced by biochemical changes in the host hemolymph composition, Diatraea saccharalis. Changes in the composition of macronutrients may occur due to the hosts own development or by changes induced after parasitization. These changes occur to facilitate parasitoid invasion and to make the host internal environment suitable to parasitoid immature development. Therefore, changes in the availability of stored and circulating nutrients may correlate with the nutritional requirements of specific parasitoid immature stages. In here, we describe changes in the biochemical composition of parasitized and control larvae at different stages of parasitoid development to gain information on C flavipes host regulation and on its quantitative immature nutritional requirements. Total proteins, lipids and carbohydrates free in the hemolymph or stored in host fat bodies, and the SDS-PAGE protein profile of the hemolymph were evaluated in control and parasitized 6th instar during the whole parasitoid development. Changes in the total protein available in the host hemolymph were detected soon after parasitization, but carbohydrate and lipids were observed to differ only towards parasitoid larvae egression. Although C. flavipes affected the availability of all macronutrients observed in the host hemolymph, lipids and proteins stored in the host fat bodies were unaffected. However, carbohydrate concentration at the end of parasitoid larval development was much lower in parasitized than in control larvae at the same stage of development. SDS-PAGE analysis indicated C flavipes up-regulated two host proteins (125 and 48 kDa) and released two parasitism-specific proteins towards the end of parasitoid larval development. We provide a discussion on the role these changes may have on the process of host regulation and their possible requirement to sustain parasitoid development. (C) 2007 Elsevier Inc. All rights reserved.

Oviposition by a moth suppresses constitutive and herbivore-induced plant volatiles in maize

Plant volatiles function as important signals for herbivores, parasitoids, predators, and neighboring plants. Herbivore attack can dramatically increase plant volatile emissions in many species. However, plants do not only react to herbivore-inflicted damage, but also already start adjusting their metabolism upon egg deposition by insects. Several studies have found evidence that egg deposition itself can induce the release of volatiles, but little is known about the effects of oviposition on the volatiles released in response to subsequent herbivory. To study this we measured the effect of oviposition by Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) moths on constitutive and herbivore-induced volatiles in maize (Zea mays L.). Results demonstrate that egg deposition reduces the constitutive emission of volatiles and suppresses the typical burst of inducible volatiles following mechanical damage and application of caterpillar regurgitant, a treatment that mimics herbivory. We discuss the possible mechanisms responsible for reducing the plant`s signaling capacity triggered by S. frugiperda oviposition and how suppression of volatile organic compounds can influence the interaction between the plant, the herbivore, and other organisms in its environment. Future studies should consider oviposition as a potential modulator of plant responses to insect herbivores.

Relationships between gene polymorphisms of folate-related proteins and vitamins and metabolites in pregnant women and neonates

Background: The methylenetetrahydrofolate reductase (MTHFR), glutamate carboxypeptidase II (GCPII) and reduced folate carrier (RFC1) gene polymorphisms were associated with folate status. We investigated the effects of these polymorphisms on serum folate (SF) and folate-related metabolites in mothers and their neonates. Methods: Cobalamin (Cbl), SF, total homocysteine (tHcy), methylmalonic acid (MMA), S-adenosylmethionine (SAM), and S-adenosylhomocysteine (SAH) were measured in 275 healthy women and their neonates. MTHFR C677T, GCPII C1561T and RFC1 A80G polymorphisms were determined by PCR-RFLP. Results: Maternal tHcy was affected individually by MTHFR C677T and GCPII C1561T polymorphisms and by combined genotypes MTHFR 677TT/GCPII 1561CC and MTHFR 677TT/RFC1 80AG. The MTHFR and RFC1 polymorphisms were not associated with variations in vitamins or SAM, SAH and MMA in neonates. Neonatal tHcy was predicted directly by maternal tHcy and inversely by maternal SF, neonatal Cbl and neonatal RFC1 80G allele (AG+GG genotypes). Maternal MMA and SAM/SAH were predicted by creatinine and Cbl, respectively. Neonatal MMA was predicted by maternal MMA and GCPII 1561T allele (CT+TT genotypes) and by neonatal Cbl. Conclusions: Maternal tHcy was affected by MTHFR C677T, RFC1 A80G and GCPII C1561T polymorphisms. Maternal GCPII C1561T variant was associated with neonatal MMA. Neonatal RFC1 A80G polymorphism influenced tHcy in neonates. (C) 2008 Elsevier B.V. All rights reserved.

In vitro characterization of rosiglitazone metabolites and determination of the kinetic parameters employing rat liver microsomal fraction

Rosiglitazone (RSG), a thiazolidinedione antidiabetic drug, is metabolized by CYP450 enzymes into two main metabolites: N-desmethyl rosiglitazone (N-Dm-R) and rho-hydroxy rosiglitazone (rho-OH-R). In humans, CYP2C8 appears to have a major role in RSG metabolism. On the other hand, the in vitro metabolism of RSG in animals has not been described in literature yet. Based on these concerns, the kinetic metabolism study of RSG using rat liver microsomal fraction is described for the first time. Maximum velocity (V (max)) values of 87.29 and 51.09 nmol/min/mg protein were observed for N-Dm-R and rho-OH-R, respectively. Michaelis-Menten constant (K (m)) values were of 58.12 and 78.52 mu M for N-Dm-R and rho-OH-R, respectively. Therefore, these results demonstrated that this in vitro metabolism model presents the capacity of forming higher levels of N-Dm-R than of rho-OH-R, which also happens in humans. Three other metabolites were identified employing mass spectrometry detection under positive electrospray ionization: ortho-hydroxy-rosiglitazone (omicron-OH-R) and two isomers of N-desmethyl hydroxy-rosiglitazone. These metabolites have also been observed in humans. The results observed in this study indicate that rats could be a satisfactory model for RSG metabolism.

Enantioselective determination of chloroquine and its n-dealkylated metabolites in plasma using liquid-phase microextraction and LC-MS

A selective method using three-phase liquid-phase microextraction (LPME) in conjunction with LC-MS-MS was devised for the enantioselective determination of chloroquine and its n-dealkylated metabolites in plasma samples. After alkalinization of the samples, the analytes were extracted into n-octanol immobilized in the pores of a polypropylene hollow fiber membrane and back extracted into the acidic acceptor phase (0.1 M TFA) filled into the lumen of the hollow fiber. Following LPME, the analytes were resolved on a Chirobiotic V column using methanol/ACN/glacial aceti acid/diethylamine (90:10:0.5:0.5 by volume) as the mobile phase. The MS detection was carried out using multiple reaction monitoring with ESI in the positive ion mode. The optimized LPME method yielded extraction recoveries ranging from 28 to 66%. The method was linear over 5 - 500 ng/mL and precision (RSD) and accuracy (relative error) values were below 15% for all analytes. The developed method was applied to the determination of the analytes in rat plasma samples after oral administration of the racemic drug.

Enantioselective analysis of zopiclone and its metabolites in plasma by liquid chromatography/tandem mass spectrometry

A high-performance liquid chromatographic method with triple-quadrupole mass spectrometry detection (LC-MS-MS) was developed and validated for the first time for the simultaneous quantification of zopiclone and its metabolites in rat plasma samples. The analytes were isolated from rat plasma by liquid-liquid extraction and separated using a chiral stationary phase based on an amylose derivative, Chiralpak ADR-H column, and ethanol-methanol-acetonitrile (50:45:5, v/v/v) plus 0.025% diethylamine as the mobile phase, at a flow-rate of 1.0 mL min(-1). Moclobemide was used as the internal standard. The developed method was linear over the concentration range of 7.5-500 ng mL(-1). The mean absolute recoveries were 74.6 and 75.7; 61.6 and 56.9; 72.5, and 70.7 for zopiclone enantiomers, for N-desmethyl zopiclone enantiomers and for zopiclone-N-oxide enantiomers, respectively, and 75.9 for the internal standard. Precision and accuracy were within acceptable levels of confidence (<15%). The method application in a pilot study of zopiclone kinetic disposition in rats showed that the levels of (+)-(S)-zopiclone were always higher than those of (-)-R-zopiclone. Higher concentrations were also observed for (+)-(S)-N-desmethyl zopiclone and (+)-(S)-N-oxide zopiclone, confirming the stereoselective disposition of zopiclone.