Regulation of Multidrug Resistance-Associated Protein 2 by Calcium Signaling in Mouse Liver

Mu hiding resistance associated protein 2 (Mrp2) is a canalicular transporter responsible for organic anion secretion into bile. Mrp2 activity is regulated by insertion into the plasma membrane; however, the factors that control this are not understood. Calcium (Ca(2+)) signaling regulates exocytosis of vesicles in most cell types, and the type II inositol 1,4,5-triphosphate receptor (InsP(3)R2) regulates Ca(2+) release in the canalicular region of hepatocytes. However, the role of InsP(3)R2 and of Ca(2+) signals in canalicular insertion and function of Mrp2 is not known. The aim of this study was to determine the role of InsP(3)R2-mediated Ca(2+) signals in targeting Mrp2 to the canalicular membrane. Livers, isolated hepatocytes, and hepatocytes in collagen sandwich culture from wild-type (WT) and InsP(3)R2 knockout (KO) mice were used for western blots, confocal immunofluorescence, and time-lapse imaging of Ca(2+) signals and of secretion of a fluorescent organic anion. Plasma membrane insertion of green fluorescent protein (GFP)-Mrp2 expressed in HepG2 cells was monitored by total internal reflection microscopy. InsP(3)R2 was concentrated in the canalicular region of WT mice but absent in InsP(3)R2 KO livers, whereas expression and localization of InsP(3)R1 was preserved, and InsP(3)R3 was absent from both WT and KO livers. Ca(2+) signals induced by either adenosine triphosphate (ATP) or vasopressin were impaired in hepatocytes lacking InsP(3)R2. Canalicular secretion of the organic anion 5-chloromethylfluorescein diacetate (CMFDA) was reduced in KO hepatocytes, as well as in WT hepatocytes treated with 1,2-bis(o-aminophenoxy)ethane-N,N,N`,N`-tetra-acetic acid (BAPTA). Moreover, the choleretic effect of tauroursodeoxycholic acid (TUDCA) was impaired in InsP(3)R2 KO mice. Finally, ATP increased GFP-Mrp2 fluorescence in the plasma membrane of HepG2 cells, and this also was reduced by BAPTA. Conclusion: InsP(3)R2-mediated Ca(2+) signals enhance organic anion secretion into bile by targeting Mrp2 to the canalicular membrane. (HEPATOLOGY 2010;52:327-337)

Exercise training enhances rat pancreatic islets anaplerotic enzymes content despite reduced insulin secretion

Endurance exercise has been shown to reduce pancreatic islets glucose-stimulated insulin secretion (GSIS). Anaplerotic/cataplerotic pathways are directly related to GSIS signaling. However, the effect of endurance training upon pancreatic islets anaplerotic enzymes is still unknown. In this sense, we tested the hypothesis that endurance exercise decreases GSIS by reducing anaplerotic/cataplerotic enzymes content. Male Wistar rats were randomly assigned to one of the four experimental groups as follows: control sedentary group (CTL), trained 1 day per week (TRE1x), trained 3 days per week (TRE3x) and trained 5 days per week (TRE5x) and submitted to an 8 weeks endurance-training protocol. After the training protocol, pancreatic islets were isolated and incubated with basal (2.8 mM) and stimulating (16.7 mM) glucose concentrations for GSIS measurement by radioimmunoassay. In addition, pyruvate carboxylase (PYC), pyruvate dehydrogenase (PDH), pyruvate dehydrogenase kinase 4 (PDK4), ATP-citrate lyase (ACL) and glutamate dehydrogenase (GDH) content were quantified by western blotting. Our data showed that 8 weeks of chronic endurance exercise reduced GSIS by 50% in a dose-response manner according to weekly exercise frequency. PYC showed significant twofold increase in TRE3x. PYC enhancement was even higher in TRE5x (p < 0.0001). PDH and PDK4 reached significant 25 and 50% enhancement, respectively compared with CTL. ACL and GDH also reported significant 50 and 75% increase, respectively. The absence of exercise-induced correlations among GSIS and anaplerotic/cataplerotic enzymes suggests that exercise may control insulin release by activating other signaling pathways. The observed anaplerotic and cataplerotic enzymes enhancement might be related to beta-cell surviving rather than insulin secretion.

Influence of NaHCO(3) Powder on Translucency of Microfilled Composite Resin Immersed in Different Mouthrinses

The regular use of mouthrinses, particularly when combined with the use of air-powder polishing, could affect the appearance of tooth-colored restorations. The current study sought to evaluate the effect of NaHCO(3) powder on translucency of a microfilled composite resin immersed in different mouthrinses, at distinct evaluation periods. Eighty disk-shaped specimens of composite resin (Durafill VS, Heraeus Kulzer GmbH & Co. KG, Hanau, Germany) were prepared. The composite specimens were then randomly allocated into two groups according to the surface treatment: exposure to NaHCO(3) powder (10 seconds) or nonexposure, and they were randomly assigned into four subgroups, according to the mouthrinses employed (N = 10): Periogard (Colgate/Palmolive, Sao Bernardo do Campo, SP, Brazil), Cepacol (Aventis Pharma, Sao Paulo, SP, Brazil), Plax (Colgate/Palmolive), and distilled water (control group). The samples were immersed for 2 minutes daily, 5 days per week, over a 4-month test period. Translucency was measured with a transmission densitometer at seven evaluation periods. Statistical analyses (analysis of variance and Tukey`s test) revealed that: distilled water presented higher translucency values (86.72%); Periogard demonstrated the lowest translucency values (72.70%); and Plax (74.05%) and Cepacol (73.32%) showed intermediate translucency values, which were statistically similar between them (p > 0.01). NaHCO(3) air-powder polishing increased the changes in translucency associated with the mouthrinses. Air-powder polishing alone had no effect on material translucency. Translucency percent was gradually decreased from 1 week of immersion up to 4 months. It may be concluded that the NaHCO(3) powder and the tested mouthrinses have affected the translucency of microfilled composite resin, according to the tested time. CLINICAL SIGNIFICANCE During the last decade, the demand for composite resin restorations has grown considerably, however, controversy persists regarding the effect of surface roughness on color stability.

LAURENCIA MARILZAE (CERAMIALES, RHODOPHYTA) FROM THE MEXICAN CARIBBEAN: A NEW RECORD FOR THE TROPICAL WESTERN ATLANTIC

Laurencia marilzae Gil-Rodriguez, Senties & MT Fujii is recorded for the first time for the tropical western Atlantic Ocean, occurring in Isla Mujeres, Quintana Roo, Mexican Caribbean. The specimens were collected in November 2008 and June 2009, growing epilithically in the lower intertidal zone on moderately exposed rocky shores. This species is characterized by its distinctive yellow-orange color in the natural environment, four pericentral cells per vegetative axial segment, the presence of secondary pit-connections between adjacent cortical cells, which are markedly projecting at the apices, and by the presence of one ""corp en cerise"" per cell in all cells of the thallus: cortical, medullary, including pericentral and axial cells, and trichoblasts. Morphological similarities and molecular data support the determination of this material as L. marilzae. The present study expands the geographical distribution of L. marilzae to the Caribbean Sea in the tropical Western Atlantic Ocean.

Postnatal fluoxetine treatment affects the development of serotonergic neurons in rats

The goal of the present study was to investigate morphological changes in the serotonergic neurons/terminals in the dorsal (DR) and median (MnR) raphe nuclei and on the hippocampal dentate gyrus (DG) in neonatal rats treated from the 1st to the 21st postnatal day with fluoxetine (10 mg/kg sc, daily) or drug vehicle (0 9% saline 1 ml/kg). The results show that postnatal chronic treatment with fluoxetine promoted. (1) a smaller body weight increase during the pre-weaning period; (2) smaller number of 5-HT neurons in the DR, (3) smaller 5-HT neuronal cell bodies (area, perimeter and diameter) in the DR and the MnR and (4) diminished serotonergic terminals in the DG. These data suggest that the development of the serotonergic system was impaired and that early exposure to fluoxetine damaged the morphology of 5-HT neurons in young adult rats While these findings are consistent with other work, more studies are needed to better clarify the effects of postnatal chronic treatment with fluoxetine on the serotonergic system and, consequently, on the functions modulated by serotonin (C) 2010 Elsevier Ireland Ltd All rights reserved

Distinctive Immunomodulatory and Inflammatory Properties of the Escherichia coli Type II Heat-Labile Enterotoxin LT-IIa and Its B Pentamer following Intradermal Administration

The type I and type II heat-labile enterotoxins (LT-I and LT-II) are strong mucosal adjuvants when they are coadministered with soluble antigens. Nonetheless, data on the parenteral adjuvant activities of LT-II are still limited. Particularly, no previous study has evaluated the adjuvant effects and induced inflammatory reactions of LT-II holotoxins or their B pentameric subunits after delivery via the intradermal (i.d.) route to mice. In the present report, the adjuvant and local skin inflammatory effects of LT-IIa and its B subunit pentamer (LT-IIaB(5)) were determined. When coadministered with ovalbumin (OVA), LT-IIa and, to a lesser extent, LT-IIaB(5) exhibited serum IgG adjuvant effects. In addition, LT-IIa but not LT-IIaB(5) induced T cell-specific anti-OVA responses, particularly in respect to induction of antigen-specific cytotoxic CD8(+) T cell responses. LT-IIa and LT-IIaB(5) induced differential tissue permeability and local inflammatory reactions after i.d. injection. Of particular interest was the reduced or complete lack of local reactions, such as edema and tissue induration, in mice i.d. inoculated with LT-IIa and LT-IIaB(5), respectively, compared with mice immunized with LT-I. In conclusion, the present results show that LT-IIa and, to a lesser extent, LT-IIaB(5) exert adjuvant effects when they are delivered via the i.d. route. In addition, the low inflammatory effects of LT-IIa and LT-IIaB(5) in comparison to those of LT-I support the usefulness of LT-IIa and LT-IIaB(5) as parenterally delivered vaccine adjuvants.

Circadian phase and intertrial interval interfere with social recognition memory

A modified version of the social habituation/dis-habituation paradigm was employed to examine social recognition memory in Wistar rats during two opposing (active and inactive) circadian phases, using different intertrial intervals (30 and 60 min). Wheel-running activity was monitored continuously to identify circadian phase. To avoid possible masking effects of the light-dark cycle, the rats were synchronized to a skeleton photoperiod, which allowed testing during different circadian phases under identical lighting conditions. In each trial, an infantile intruder was introduced into an adult`s home-cage for a 5-minute interaction session, and social behaviors were registered. Rats were exposed to 5 trials per day for 4 consecutive days: oil days I and 2, each resident was exposed to the same intruder; on days 3 and 4, each resident was exposed to a different intruder in each trial. I he resident`s social investigatory behavior was more intense when different intruders were presented compared to repeated presentation of the same intruder, suggesting social recognition memory. This effect was stronger when the rats were tested during the inactive phase and when the intertrial interval was 60 min, These findings Suggest that social recognition memory, as evaluated in this modified habituation/dis-habituation paradigm, is influenced by the circadian rhythm phase during which testing is performed, and by intertrial interval. (C) 2008 Elsevier Inc. All rights reserved.

Analysis of genotypic variation in genes associated with virulence in Aggregatibacter actinomycetemcomitans clinical isolates

Background and Objective: Although certain serotypes of Aggregatibacter actinomycetemcomitans are associated more with aggressive periodontitis than are other serotypes, the correlation between distinct lineages and virulence traits in this species is poorly understood. This study aimed to evaluate the polymorphism of genes encoding putative virulence factors of clinical isolates, and to correlate these findings with A. actinomycetemcomitans serotypes, genotypes and periodontal status of the hosts. Material and Methods: Twenty-six clinical isolates from diverse geographic populations with different periodontal conditions were evaluated. Genotyping was performed using pulse-field gel electrophoresis. Polymorphisms in the genes encoding leukotoxin, Aae, ApaH and determinants for serotype-specific O polysaccharide were investigated. Results: The isolates were classified into serotypes a-f, and exhibited three apaH genotypes, five aae alleles and 25 macrorestriction profiles. Two serotype b isolates (7.7%), obtained from Brazilian patients with aggressive periodontitis, were associated with the highly leukotoxic genotype; these isolates showed identical fingerprint patterns and aae and apaH genotypes. Serotype c, obtained from various periodontal conditions, was the most prevalent among Brazilian isolates, and isolates were distributed in two aae alleles, but formed a genetically distinct group based on apaH analysis. Cluster analysis showed a close relationship between fingerprinting genotypes and serotypes/apaH genotypes, but not with aae genotypes. Conclusion: Apart from the deletion in the ltx promoter region, no disease-associated markers were identified. Non-JP2-like strains recovered from individuals with periodontal disease exhibited considerable genetic variation regarding aae/apaH genotypes, serotypes and XhoI DNA fingerprints.

Clopidogrel, independent of the vascular P2Y(12) receptor, improves arterial function in small mesenteric arteries from Angll-hypertensive rats

The P2Y(12) receptor antagonist clopidogrel blocks platelet aggregation, improves systemic endothelial nitric oxide bioavailability and has anti-inflammatory effects. Since P2Y(12) receptors have been identified in the vasculature, we hypothesized that clopidogrel ameliorates Angll (angiotensin II)-induced vascular functional changes by blockade of P2Y(12) receptors in the vasculature. Male Sprague Dawley rats were infused with Angll (60 ng/min) or vehicle for 14 days. The animals were treated with clopidogrel (10 mg . kg(-1) of body weight . day(-1)) or vehicle. Vascular reactivity was evaluated in second-order mesenteric arteries. Clopidogrel treatment did not change systolic blood pressure [(mmHg) control-vehicle, 117 +/- 7.1 versus control-clopidogrel, 125 +/- 4.2; Angll vehicle, 197 +/- 10.7 versus Angll clopidogrel, 198 +/- 5.2], but it normalized increased phenylephrine-induced vascular contractions [(%KCI) vehicle-treated, 182.2 +/- 18% versus clopidogrel, 133 +/- 14%), as well as impaired vasodilation to acetylcholine [(%) vehicle-treated, 71.7 +/- 2.2 versus clopidogrel, 85.3 +/- 2.8) in Angll-treated animals. Vascular expression of P2Y(12) receptor was determined by Western blot. Pharmacological characterization of vascular P2Y(12) was performed with the P2Y(12) agonist 2-MeS-ADP [2-(methylthio) adenosine 5`-trihydrogen diphosphate trisodium]. Although 2-MeS-ADP induced endothelium-dependent relaxation [(Emax %) = 71 +/- 12%) as well as contractile vascular responses (Emax % = 83 +/- 12%), these actions are not mediated by P2Y(12) receptor activation. 2-MeS-ADP produced similar vascular responses in control and Angll rats. These results indicate potential effects of clopidogrel, such as improvement of hypertension-related vascular functional changes that are not associated with direct actions of clopidogrel in the vasculature, supporting the concept that activated platelets contribute to endothelial dysfunction, possibly via impaired nitric oxide bioavailability.

Glucocorticoids in Vivo Induce Both Insulin Hypersecretion and Enhanced Glucose Sensitivity of Stimulus-Secretion Coupling in Isolated Rat Islets

Although glucocorticoids are widely used as antiinflammatory agents in clinical therapies, they may cause serious side effects that include insulin resistance and hyperinsulinemia. To study the potential functional adaptations of the islet of Langerhans to in vivo glucocorticoid treatment, adult Wistar rats received dexamethasone (DEX) for 5 consecutive days, whereas controls (CTL) received only saline. The analysis of insulin release in freshly isolated islets showed an enhanced secretion in response to glucose in DEX-treated rats. The study of Ca(2+) signals by fluorescence microscopy also demonstrated a higher response to glucose in islets from DEX-treated animals. However, no differences in Ca(2+) signals were found between both groups with tolbutamide or KCl, indicating that the alterations were probably related to metabolism. Thus, mitochondrial function was explored by monitoring oxidation of nicotinamide dinucleotide phosphate autofluorescence and mitochondrial membrane potential. Both parameters revealed a higher response to glucose in islets from DEX-treated rats. The mRNA and protein content of glucose transporter-2, glucokinase, and pyruvate kinase was similar in both groups, indicating that changes in these proteins were probably not involved in the increased mitochondrial function. Additionally, we explored the status of Ca(2+)-dependent signaling kinases. Unlike calmodulin kinase II, we found an augmented phosphorylation level of protein kinase C alpha as well as an increased response of the phospholipase C/inositol 1,4,5-triphosphate pathway in DEX-treated rats. Finally, an increased number of docked secretory granules were observed in the beta-cells of DEX animals using transmission electron microscopy. Thus, these results demonstrate that islets from glucocorticoid-treated rats develop several adaptations that lead to an enhanced stimulus-secretion coupling and secretory capacity. (Endocrinology 151: 85-95, 2010)

Adsorption of Pb(2+), Cu(2+) and Cd(2+) in FDU-1 silica and FDU-1 silica modified with humic acid

Ordered mesoporous silica with cubic structure, type FDU-1, was synthesized under strong acid media using B-50-6600 poly(ethylene oxide)-poly(butilene oxide)-poly(ethylene oxide) triblock copolymer (EO(39)BO(47)EO(39)) and tetraethyl orthosilicate (TEOS). Humic acid (HA) was modified to the synthesis process at a concentration of 1.5 mmol per gram of SiO(2). Thermogravimetry, small angle X-ray diffraction, nitrogen adsorption and high resolution transmission electron microscopy were used to characterize the samples. The pristine FDU-1 and FDU-1 with incorporated 1.5 mmol of HA were tested for adsorption of Pb(2+), Cu(2+) and Cd(2+) in aqueous solution. Incorporation of humic acid into the FDU-1 silica afforded an adsorbent with strong affinity for Cd(2+), Cu(2+) and Pb(2+) from single ion solutions. Adsorption of Cu(2+) was significantly enhanced after incorporation of humic acid, a fact that can be explained by the formation of complexes with carboxylic and phenolic groups at low concentrations of the metal cation. The results demonstrated the potential applicability of FDU-1 with incorporated HA in the removal of low concentrations of heavy metal cations from aqueous solution, such as wastewaters, after usual precipitation of metal hydroxides in alkaline medium and proper pH conditioning in the range between 6 and 7. (C) 2007 Elsevier Inc. All rights reserved.

Chemostratigraphy of the Tamengo Formation (Corumba Group, Brazil) A contribution to the calibration of the Ediacaran carbon-isotope curve

The Corumba Group cropping out in the southern Paraguay Belt in Brazil is one of the most complete Ediacaran sedimentary archives of palaeogeographic climatic biogeochemical and biotic evolution in southwestern Gondwana The unit hosts a rich fossil record including acritarchs vendotaenids (Vendo taenia Eoholynia) soft-bodied metazoans (Corumbella) and skeletal fossils (Cloudina Titanotheca) The Tamengo Formation made up mainly of limestones and marls provides a rich bio- and chemostratigraphic record Several outcrops formerly assigned to the Cuiaba Group are here included in the Tamengo Formation on the basis of lithological and chemostratigraphical criteria High-resolution carbon isotopic analyses are reported for the Tamengo Formation showing (from base to top) (1) a positive delta(13)C excursion to +4 parts per thousand PDB above post-glacial negative values (2) a negative excursion to -3 5 parts per thousand associated with a marked regression and subsequent transgression (3) a positive excursion to +5 5 parts per thousand and (4) a plateau characterized by delta(13)C around +3 parts per thousand A U-Pb SHRIMP zircon age of an ash bed Interbedded in the upper part of the delta(13)C positive plateau yielded 543 +/- 3 Ma which is considered as the depositional age (Babinski et al 2008a) The positive plateau in the upper Tamengo Formation and the preceding positive excursion are ubiquitous features in several successions worldwide including the Nama Group (Namibia) the Dengying Formation (South China) and the Nafun and Ara groups (Oman) This plateau is constrained between 542 and 551 Ma thus consistent with the age of the upper Tamengo Formation The negative excursion of the lower Tamengo Formation may be correlated to the Shuram-Wonoka negative anomaly although delta(13)C values do not fall beyond -3 5 parts per thousand in the Brazilian sections Sedimentary breccias occur just beneath this negative excursion in the lower Tamengo Formation One possible interpretation of the origin of these breccias is a glacioeustatic sea-level fall but a tectonic interpretation cannot be completely ruled out Published by Elsevier B V

P-T-Fluid evolution and graphite deposition during retrograde metamorphism in Ribeira Fold Belt, SE Brazil: Oxygen fugacity, fluid inclusions and C-O-H isotopic evidence

Combined fluid inclusion (FI) microthermometry, Raman spectroscopy, X-ray diffraction, C-O-H isotopes and oxygen fugacities of granulites from central Ribeira Fold Belt, SE Brazil, provided the following results: i) Magnetite-Hematite fO(2) estimates range from 10(-11.5) bar (QFM + 1) to 10(-18.3) bar (QFM - 1) for the temperature range of 896 degrees C-656 degrees C, implying fO(2) decrease from metamorphic peak temperatures to retrograde conditions; ii) 5 main types of fluid inclusions were observed: a) CO(2) and CO(2)-N(2) (0-11 mol%) high to medium density (1.01-0.59 g/cm(3)) FI; b) CO(2) and CO(2)-N(2) (0-36 mol%) low density (0.19-0.29 g/cm(3)) FI; c) CO(2) (94-95 mol%)-N(2) (3 mol%)-CH(4) (2-3 mol%)-H(2)O (water phi(v) (25 degrees C) = 0.1) FI; d) low-salinity H(2)O-CO(2) FI; and e) late low-salinity H(2)O FI; iii) Raman analyses evidence two graphite types in khondalites: an early highly ordered graphite (T similar to 450 degrees C) overgrown by a disordered kind (T similar to 330 degrees C); iv) delta(18)O quartz results of 10.3-10.7 parts per thousand, imply high-temperature CO(2) delta(18)O values of 14.4-14.8 parts per thousand, suggesting the involvement of a metamorphic fluid, whereas lower temperature biotite delta(18)O and delta D results of 7.5-8.5 parts per thousand and -54 to -67 parts per thousand respectively imply H(2)O delta(18)O values of 10-11 parts per thousand and delta D(H2O) of -23 to -36 parts per thousand suggesting delta(18)O depletion and increasing fluid/rock ratio from metamorphic peak to retrograde conditions. Isotopic results are compatible with low-temperature H(2)O influx and fO(2) decrease that promoted graphite deposition in retrograde granulites, simultaneous with low density CO(2), CO(2)-N(2) and CO(2)-N(2)-CH(4)-H(2)O fluid inclusions at T = 450-330 degrees C. Graphite delta(13)C results of -10.9 to -11.4 parts per thousand imply CO(2) delta(13)C values of -0.8 to -1.3 parts per thousand suggesting decarbonation of Cambrian marine carbonates with small admixture of lighter biogenic or mantle derived fluids. Based on these results, it is suggested that metamorphic fluids from the central segment of Ribeira Fold Belt evolved to CO(2)-N(2) fluids during granulitic metamorphism at high fO(2), followed by rapid pressure drop at T similar to 400-450 degrees C during late exhumation that caused fO(2) reduction induced by temperature decrease and water influx, turning carbonic fluids into CO(2)-H(2)O (depleting biotite delta(18)O and delta D values), and progressively into H(2)O. When fO(2) decreased substantially by mixture of carbonic and aqueous fluids, graphite deposited forming khondalites. (C) 2010 Elsevier Ltd. All rights reserved.

Boron isotope composition of tourmalinite and vein tourmalines associated with gold mineralization, Serra do Itaberaba Group, central Ribeira Belt, SE Brazil

Important concentrations of tourmaline occur as gold-bearing stratiform tourmalinites and in mineralized quartz-tourmaline veins at the Tapera Grande and Quartzito gold prospects in the Mesoproterozoic Serra do Itaberaba Group, central Ribeira Belt (Sao Paulo State, SE Brazil). The main rock types in both prospects constitute the volcanic-sedimentary Morro da Pedra Preta Formation, which formed in a submarine back-arc setting. At Tapera Grande, the volcanic-sedimentary sequence is composed of metabasic and metavolcaniclastic rocks, graphitic and sulfur-rich metapelites, banded iron formation, metandesite, metarhyolite, calcsilicates, tourmalinites and metahydrothermalites derived from mafic and felsic rocks. The Mesoproterozoic rocks at Quartzito prospect are lithologically similar but they have been affected by Neoproterozoic faulting and shearing and by the emplacement of granitic rocks, resulting in the formation of tourmaline-rich quartz-carbonate veins with gold and base metal mineralization. We conducted a chemical and B-isotope study of tourmalines in order to better understand the origin of the stratiform tourmalinites in the Morro da Pedra Preta Formation and their relationship with gold mineralization. The overall range of delta(11)B values obtained for the tourmalinite and vein tourmalines is between - 15%. and -5 parts per thousand, with the tourmalinites failing at the low end of this range (-15 to -8 parts per thousand). Such values are typical for continental crust and inconsistent with a primary marine boron signature as expected from the submarine-exhalative model for the gold prospects. We conclude from this that tourmaline formed or recrystallized from crustal fluids related to the amphibolite-grade metamorphism which affected the Serra do Itaberaba Group and that gold deposition occurred syn- to post-peak metamorphism by phase immiscibility, as attested by fluid inclusions in Tapera Grande tourmalinite tourmaline and quartz. The vein-hosted tourmalines at Quartzito have isotopically variable boron signatures, with heavier delta(11)B values of -5 parts per thousand to -8 parts per thousand for acicular green tourmalines and lighter values (-15 parts per thousand to -7 parts per thousand for light blue, Ti-firee tourmaline from quartz-carbonate veins). We attribute the heavier boron to fluids derived from the volcano-sedimentary rocks of marine affinity whereas the lighter boron was contributed by crustal fluids related to the granitoids or metasediments in the continental crust. (c) 2009 Elsevier B.V. All rights reserved.