A Model for comparing reduced impact logging with conventional logging for an Eastern Amazonian Forest

Using data from a logging experiment in the eastern Brazilian Amazon region, we develop a matrix growth and yield model that captures the dynamic effects of harvest system choice on forest structure and composition. Multinomial logistic regression is used to estimate the growth transition parameters for a 10-year time step, while a Poisson regression model is used to estimate recruitment parameters. The model is designed to be easily integrated with an economic model of decisionmaking to perform tropical forest policy analysis. The model is used to compare the long-run structure and composition of a stand arising from the choice of implementing either conventional logging techniques or more carefully planned and executed reduced-impact logging (RIL) techniques, contrasted against a baseline projection of an unlogged forest. Results from log and leave scenarios show that a stand logged according to Brazilian management requirements will require well over 120 years to recover its initial commercial volume, regardless of logging technique employed. Implementing RIL, however, accelerates this recovery. Scenarios imposing a 40-year cutting cycle raise the possibility of sustainable harvest volumes, although at significantly lower levels than is implied by current regulations. Meeting current Brazilian forest policy goals may require an increase in the planned total area of permanent production forest or the widespread adoption of silvicultural practices that increase stand recovery and volume accumulation rates after RIL harvests. Published by Elsevier B.V.

Variation of wood density and relationship with the tree-ring width of mahogany trees, Swietenia macrophylla, from Amazonian tropical forest of Peru

Mahogany trees, Swietenia macrophylla, occur in open rainforest, semi deciduous and deciduous and dense rainforest of Peruvian Amazonian tropical forest. They occur, preferentially, in areas with a defined dry season, with typical phenology and seasonal variation activity, forming distinct tree-rings. The present work had as aim to determine the wood density radial variation of 14 mahogany trees, of two populations of the Peruvian Amazonian tropical forest, through the X-ray densitometry and to evaluate their application as methodology, compared to the classic method of measurement table, for the determination of the treering width. The radial wood apparent density of the trees profiles rendered it possible to delimit the areas of juvenile-adult wood and of the heartwood-sapwood, relative to the anatomical structure and chemical composition differences, due to the extractives and the vessels obstruction by tyloses. The mean, minimum and maximum wood apparent density of the mahogany trees for the Populations A and B were of 0.70; 0.29; 1.01 g.cm(-3) and 0.81; 0.29; 1.19 g.cm(-3), respectively. The analysis of the variance and mean test indicate differences of mean wood density among the mahogany trees of each population, probably due to the age of the trees. There was no correlation between mean wood density of mahogany trees among the two populations, as well as, between the tree-ring width and the respective mean density. The X-ray densitometry technique is an important tool in the evaluation of the radial variation of wood apparent density and the delimitation of tree-ring boundaries, with correlations of 0.94 and 0.93 in relation to measurement table, for each sampled population.

A phospholipase A(2) from Bothrops asper snake venom activates neutrophils in culture: Expression of cyclooxygenase-2 and PGE(2) biosynthesis

In this study, the production of prostaglandin E(2) (PGE(2)) and up-regulation in cyclooxygenase (COX) pathway induced by a phospholipase A(2) (PLA(2)), myotoxin-III (MT-III), purified from Bothrops asper snake venom, in isolated neutrophils were investigated. The arachidonic acid (AA) production and the participation of intracellular PLA(2)s (cytosolic PLA(2) and Ca(2+)-independent PLA(2)) in these events were also evaluated. MT-III induced COX-2, but not COX-1 gene and protein expression in neutrophils and increased PGE(2) levels. Pretreatment of neutrophils with COX-2 and COX-1 inhibitors reduced PGE(2) production induced by MT-III. Arachidonyl trifluoromethyl ketone (AACOCF(3)), an intracellular PLA(2) inhibitor, but not bromoenol lactone (BEL), an iPLA(2) inhibitor, suppressed the MT-III-induced AA and PGE(2) release. In conclusion, MT-III directly stimulates neutrophils inducing COX-2 mRNA and protein expression followed by production of PGE(2). COX-2 isoform is preeminent over COX-1 for production of PGE(2) stimulated by MT-III. PGE(2) and AA release by MT-III probably is related to cPLA(2) activation. (c) 2010 Elsevier Ltd. All rights reserved.

Secretory phospholipases A(2) isolated from Bothrops asper and from Crotalus durissus terrificus snake venoms induce distinct mechanisms for biosynthesis of prostaglandins E-2 and D-2 and expression of cyclooxygenases

The effects of myotoxin III (MT-III), a phospholipase A(2) (sPLA(2)) from Bothrops asper snake venom, and crotoxin B (CB), a neurotoxic and myotoxic sPLA2 from the venom of Crotalus durissus terrificus, on cyclooxygenases (COXs) expression and biosynthesis of prostaglandins (PGs) were evaluated, together with the mechanisms involved in these effects. Upon intraperitoneal injection in mice, both sPLA(2)s promoted the synthesis of PGD(2) and PGE(2), with a different time-course. MT-III, but not CB, induced COX-2 expression by peritoneal leukocytes without modification on COX-1 constitutive expression, whereas CB increased the constitutive activity of COX-1. MT-III increased the enzymatic activity of COX-1 and COX-2. Similar effects were observed when these sPLA(2)s were incubated with isolated macrophages, evidencing a direct effect on these inflammatory cells. Moreover, both toxins elicited the release of arachidonic acid from macrophages in vitro. inhibition of cPLA(2) by AACOCF(3), but not of iPLA(2) by PACOCF(3) or BEL, significantly reduced PGD2, PGE2 and arachidonic acid (AA) release promoted by MT-III. These inhibitors did not affect MT-III-induced COX-2 expression. In contrast, cPLA2 inhibition did not modify the effects of CB, whereas iPLA2 inhibition reduced PGD2 and AA production induced by CB. These findings imply that distinct regulatory mechanisms leading to PGs` synthesis are triggered by these snake venom sPLA(2)s. Such differences are likely to explain the dissimilar patterns of inflammatory reaction elicited by these sPLA(2)s in vivo. (C) 2008 Elsevier Ltd. All rights reserved.

Gas Chromatographic Analysis of Dimethyltryptamine and beta-Carboline Alkaloids in Ayahuasca, an Amazonian Psychoactive Plant Beverage

Introduction - Ayahuasca is obtained by infusing the pounded stems of Banisteriopsis caapi in combination with the leaves of Psychotria viridis. P. viridis is rich in the psychedelic indole N,N-dimethyltryptamine, whereas B. caapi contains substantial amounts of beta-carboline alkaloids, mainly harmine, harmaline and tetrahydroharmine, which are monoamine-oxidase inhibitors. Because of differences in composition in ayahuasca preparations, a method to measure their main active constituents is needed. Objective - To develop a gas chromatographic method for the simultaneous determination of dimethyltryptamine and the main beta-carbolines found in ayahuasca preparations. Methodology - The alkaloids were extracted by means of solid phase extraction (C(18)) and detected by gas chromatography with nitrogen/phosphorous detector. Results - The lower limit of quantification (LLOQ) was 0.02 mg/mL for all analytes. The calibration curves were linear over a concentration range of 0.02-4.0 mg/mL (r(2) > 0.99). The method was also precise (RSD < 10%). Conclusion - A simple gas chromatographic method to determine the main alkaloids found in ayahuasca was developed and validated. The method can be useful to estimate administered doses in animals and humans for further pharmacological and toxicological investigations of ayahuasca. Copyright (C) 2009 John Wiley & Sons, Ltd.

Study of sunless tanning formulas using molted snake skin as an alternative membrane model

Sunless tanning formulas have become increasingly popular in recent years for their ability to give people convincing tans without the dangers of skin cancer. Most sunless tanners currently on the market contain dihydroxyacetone (DHA), a keto sugar with three carbons. The temporary pigment provided by these formulasis designed to resemble a UV-induced tan. This study evaluated the effectiveness of carbomer gels and cold process self emulsifying bases on skin pigmentation, using different concentrations of a chemical system composed of DHA and N-acetyl tyrosine, which are found in moulted snake skins and their effectiveness was tested by Mexameter (R) MX 18. Eight different sunless tanning formulas were developed, four of which were gels and four of which were emulsions (base, base plus 4.0%, 5.0% and 6.0% (w/w) of a system of DHA and N-acetyl tyrosine). Tests to determine the extent of artificial tanning were done by applying 30 mg cm(-2) of each formula onto standard sizes of moulted snake skin (2.0 cm x 3.0 cm). A Mexameter (R) MX 18 was used to evaluate the extent of coloration in the moulted snake skin at T(0) (before the application) and after 24, 48, 72, 168, 192 and 216 h. The moulted snake skins can be used as an alternative membrane model for in vitro sunless tanning efficacy tests due to their similarity to the human stratum corneum. The DHA concentration was found to influence the initiation of the pigmentation in both sunless tanning systems (emulsion and gel) as well as the time required to increases by a given amount on the tanning index. In the emulsion system, the DHA concentration also influenced the final value on the tanning index. The type of system (emulsion or gel) has no influence on the final value in the tanning index after 216 h for samples with the same DHA concentration.

A new acidic myotoxic, anti-platelet and prostaglandin I(2) inductor phospholipase A(2) isolated from Bothrops moojeni snake venom

Phospholipase A(2) (PLA(2), EC 3.1.1.4), a major component of snake venoms, specifically catalyzes the hydrolysis of fatty acid ester bonds at position 2 of 1,2-diacyl-sn-3-phosphoglycerides in the presence of calcium. This article reports the purification and biochemical/functional characterization of BmooTX-I, a new myotoxic acidic phospholipase A(2) from Bothrops moojeni snake venom. The purification of the enzyme was carried out through three chromatographic steps (ion-exchange on DEAE-Sepharose, molecular exclusion on Sephadex G-75 and hydrophobic chromatography on Phenyl-Sepharose). BmooTX-I was found to be a single-chain protein of 15,000 Da and pI 4.2. The N-terminal sequence revealed a high homology with other acidic Asp49 PLA(2)S from Bothrops snake venoms. It displayed a high phospholipase activity and platelet aggregation inhibition induced by collagen or ADP. Edema and myotoxicity in vivo were also induced by BmooTX-I. Analysis of myotoxic activity was carried out by optical and ultrastructural microscopy, demonstrating high levels of leukocytary infiltrate. Previous treatment of BmooTX-1 with BPB reduced its enzymatic and myotoxic activities, as well as the effect on platelet aggregation. Acidic myotoxic PLA(2)S from Bothrops snake venoms have been little explored and the knowledge of its structural and functional features will be able to contribute for a better understanding of their action mechanism regarding enzymatic and toxic activities. (C) 2008 Elsevier Ltd. All rights reserved.

Isolation and functional characterization of proinflammatory acidic phospholipase A(2) from Bothrops leucurus snake venom

In the present study, an acidic PLA(2), designated BI-PLA(2), was isolated from Bothrops leucurus snake venom through two chromatographic steps: ion-exchange on CM-Sepharose and hydrophobic chromatography on Phenyl-Sepharose. Bl-PLA(2) was homogeneous on SDS-PAGE and when submitted to 2D electrophoresis the molecular mass was 15,000 Da and pl was 5.4. Its N-terminal sequence revealed a high homology with other Asp49 acidic PLA(2)s from snake venoms. Its specific activity was 159.9 U/mg and the indirect hemolytic activity was also higher than that of the crude venom. Bl-PLA(2) induced low myotoxic and edema activities as compared to those of the crude venom. Moreover, the enzyme was able to induce increments in IL-12p40, TNF-alpha, IL-1 beta and IL-6 levels and no variation of IL-8 and IL-10 in human PBMC stimulated in vitro, suggesting that Bl-PLA2 induces proinflammatory cytokine production by human mononuclear cells. Bothrops leucurus venom is still not extensively explored and knowledge of its components will contribute for a better understanding of its action mechanism. (C) 2011 Elsevier Inc. All rights reserved.

Isolation, functional, and partial biochemical characterization of galatrox, an acidic lectin from Bothrops atrox snake venom

Snake venom lectins have been studied in regard to their chemical structure and biological functions. However, little is known about lectins isolated from Bothrops atrox snake venom. We report here the isolation and partial functional and biochemical characterization of an acidic glycan-binding protein called galatrox from this venom. This lectin was purified by affinity chromatography using a lactosyl-sepharose column, and its homogeneity and molecular mass were evaluated by high-performance liquid chromatography, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry. The purified galatrox was homogeneous and characterized as an acidic protein (pI 5.2) with a monomeric and dimeric molecular mass of 16.2 and 32.5 kDa, respectively. Alignment of N-terminal and internal amino acid sequences of galatrox indicated that this protein exhibits high homology to other C-type snake venom lectins. Galatrox showed optimal hemagglutinating activity at a concentration of 100 mu g/ml and this effect was drastically inhibited by lactose, ethylenediaminetetraacetic acid, and heating, which confirmed galatrox`s lectin activity. While galatrox failed to induce the same level of paw edema or mast cell degranulation as B. atrox crude venom, galatrox did alter cellular viability, which suggested that galatrox might contribute to venom toxicity by directly inducing cell death.

Elevated levels of selenium in the typical diet of Amazonian riverside populations

Selenium (Se) intake is generally from food, whose Se content depends on soil Se and plant accumulation. For humans, adequate Se intake is essential for several selenoenzymes. In the Lower Tapajos region of the Brazilian Amazon, Se status is elevated with large inter-community variability. Se intake in this region, where Hg exposure is among the highest in the world, may be important to counteract mercury (Hg) toxicity. The present study was conducted in 2006 with 155 persons from four communities of the Lower Tapajos. The objectives were: i) to evaluate Se content in their typical diet and drinking water; ii) to compare food Se concentrations with respect to geographic location; and iii) to examine the contribution of consumption of different food items to blood Se. More than 400 local foods and 40 drinking water samples were collected. Participants responded to an interview-administered food frequency questionnaire and provided blood samples. Food, water and blood Se levels were assessed by ICP-MS. Since Brazil nuts may also contain significant levels of barium (Ba) and strontium (Sr), these elements were likewise analyzed in nuts. The highest Se concentrations were found in Brazil nuts, but concentrations were highly variable (median: 13.9 mu g/g; range: 0.4-158.4 mu g/g). Chicken, game meat, eggs and beef also contained considerable levels of Se, with median concentrations from 0.3 to 1.4 mu g/g. There was no particular geographic distribution of food Se. Se concentration in drinking water was very low (<1.4 mu g/L). Blood Se covered a (103-1500 mu g/L), and was positively related to regular consumption of Brazil nuts, domestic chicken and game meat. Brazil nuts were found to contain highly variable and often very high concentrations of Ba (88.0 mu g/g, 1.9-1437 mu g/g) and Sr (38.7 mu g/g, 3.3-173 mu g/g). Further studies should address multiple nutrient/toxic interactions in the diet and related effects on health. (c) 2010 Elsevier B.V. All rights reserved.

BthMP: a new weakly hemorrhagic metalloproteinase from Bothrops moojeni snake venom

In this work, a new weakly hemorrhagic metalloproteinase (BthMP) was purified from Bothrops moojeni snake venom. This enzyme was homogeneous by native and SDS-PAGE. It showed a polypeptide chain of 23.5 kDa, pI=7.1, and N-terminal blocked. BthMP is comprised of high proteolytic activity on casein, fibrin and bovine fibrinogen, with no coagulating, esterase or phospholipase A(2) activities; it was inhibited by EDTA, EGTA and 1,10-phenanthroline and maintained its activity on pH from 7.0 to 9.0 and temperature from 5-40 degrees C. Assays with metal ions showed that Ca(2+) is an activator, whereas Zn(2+) and Hg(2+) inhibited about 50 and 80% of its activity, respectively. The edema evidenced the important role of the toxin in the inflammatory activity of the venom. BthMP also caused unclotting, and provoked histological alterations in the gastrocnemius muscle of mice inducing hemorrhage, necrosis and leukocytic infiltrate. The molecular mass and the inhibition assays suggest that the metal loproteinase BthMP belongs to class P-I of SVMPs. (c) 2008 Elsevier Ltd. All rights reserved.

Evidence of caspase-mediated apoptosis induced by L-amino acid oxidase isolated from Bothrops atrox snake venom

The aim of this work was to investigate the involvement of caspases in apoptosis induced by L-amino acid oxidase isolated from Bothrops atrox snake venom. The isolation of LAAO involved three chromatographic steps: molecular exclusion on a G-75 column; ion exchange column by HPLC and affinity chromatography on a Lentil Lectin column. SDS-PAGE was used to confirm the expected high purity level of BatroxLAA0. It is a glycoprotein with 12% sugar and an acidic character, as confirmed by its amino acid composition, rich in ""Asp and Glu"" residues. It displays high specificity toward hydrophobic L-amino acids. The N-terminal amino acid sequence and internal peptide sequences showed close structural homology to other snake venom LAAOs. This enzyme induces in vitro platelet aggregation, which may be due to H(2)O(2) production by LAAOs, since the addition of catalase completely inhibited the aggregation effect. It also showed cytotoxicity towards several cancer cell lines: HL60, Jurkat, B16F10 and PC12. The cytotoxicity activity was abolished by catalase. A fluorescence microscopy evaluation revealed a significant increase in the apoptotic index of these cells after BatroxLAAO treatment. This observation was confirmed by phosphatidyl serine exposure and activation of caspases. BatroxLAAO is a protein with various biological functions that can be involved in envenomation. Further investigations of its function will contribute to toxicology advances. Published by Elsevier Inc.

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.

Antiviral and antiparasite properties of an L-amino acid oxidase from the Snake Bothrops jararaca: Cloning and identification of a complete cDNA sequence (Retracted article. See vol. 80, pg. 288, 2010)

L-Amino acid oxidases (LAAOs, EC 1.4.3.2) are flavoenzymes that catalyze the stereospecific oxidative deamination of an L-amino acid substrate to the corresponding a-ketoacid with hydrogen peroxide and ammonia production. The present work describes the first report on the antiviral (Dengue virus) and antiprotozoal (trypanocidal and leishmanicide) activities of a Bothrops jararaca L-amino acid oxidase (BjarLAAO-I) and identify its cDNA sequence. Antiparasite effects were inhibited by catalase, suggesting that they are mediated by H(2)O(2) production. Cells infected with DENV-3 virus previously treated with BjarLAAO-I, showed a decrease in viral titer (13-83-fold) when compared with cells infected with untreated viruses. Untreated and treated promastigotes (T. cruzi and L. amazonensis) were observed by transmission electron microscopy with different degrees of damage. Its complete cDNA sequence, with 1452 bp, encoded an open reading frame of 484 amino acid residues with a theoretical molecular weight and pl of 54,771.8 and 5.7, respectively. The cDNA-deduced amino acid sequence of BjarLAAO shows high identity to LAAOs from other snake venoms. Further investigations will be focused on the related molecular and functional correlation of these enzymes. Such a study should provide valuable information for the therapeutic development of new generations of microbicidal drugs. (C) 2008 Elsevier Inc. All rights reserved.