Tributyltin in Crustacean Tissues: Analytical Performance and Validation of Method

The hermit crab Clibanarius vittatus is a typical organism from intertidal regions being considered as a good bioindicator of tributyltin presence at these environments. Thus this study presents the analytical performance and validation method for TBT quantification in tissues of C. vittatus by gas chromatography with pulsed flame photometric detector (GC-PFPD) after extraction with an apolar solvent (toluene) and Grignard derivatization. The limits of detection of the method (LOD) were 2.0 and 2.8 ng g(-1) for TBT and DBT (dibutyltin), respectively, and its limits of quantification (LOQ) were 6.6 and 8.9 ng g(-1) for TBT and DBT, respectively. The method was applied to samples from Santos Estuary, Sao Paulo State, Brazil. TBT and DBT concentrations ranged from 26.7 to 175.0 ng g(-1) and from 46.2 to 156.0 ng g(-1), respectively. These concentrations are worrisome since toxic effects (such as endocrine disruption) have been reported for other organisms even under lower levels of registred at this study.

Tributyltin in crustacean tissues: analytical performance and validation of method

The hermit crab Clibanarius vittatus is a typical organism from intertidal regions being considered as a good bioindicator of tributyltin presence at these environments. Thus this study presents the analytical performance and validation method for TBT quantification in tissues of C. vittatus by gas chromatography with pulsed flame photometric detector (GC-PFPD) after extraction with an apolar solvent (toluene) and Grignard derivatization. The limits of detection of the method (LOD) were 2.0 and 2.8 ng g-1 for TBT and DBT (dibutyltin), respectively, and its limits of quantification (LOQ) were 6.6 and 8.9 ng g-1 for TBT and DBT, respectively. The method was applied to samples from Santos Estuary, São Paulo State, Brazil. TBT and DBT concentrations ranged from 26.7 to 175.0 ng g-1 and from 46.2 to 156.0 ng g-1, respectively. These concentrations are worrisome since toxic effects (such as endocrine disruption) have been reported for other organisms even under lower levels of registred at this study.

Temporal, diel and spatial variability of decapod larvae from St Paul`s Rocks, an equatorial oceanic island of Brazil

Temporal, spatial and diel variation in the distribution and abundance of organisms is an inherent property of ecological systems. The present study describes these variations and the composition of decapod larvae from the surface waters of St Paul`s Rocks. The expeditions to the archipelago were carried out in April, August and November 2003, March 2004 and May 2005. Surface plankton samples were collected during the morning and dusk periods, inside the inlet and in increasing distances around the archipelago (similar to 150, 700 and 1500 m). The identification resulted in 51 taxa. Seven species, six genera and larvae of the families Pandalidae and Portunidae were identified for the first time in the area. The mean larval density varied from zero to 150.2 +/- 69.6 individuals 100 m(-3) in the waters surrounding the archipelago and from 1.7 +/- 3.0 to 12,827 +/- 15,073 individuals 100 m(-3) inside the inlet. Significant differences on larval density were verified between months and period of the day, but not among the three sites around the archipelago. Cluster and non-metric multidimensional scaling analysis indicated that the decapod larvae community was divided into benthic and pelagic assemblages. Indicator species analysis (ISA) showed that six Brachyura taxa were good indicators for the inlet, while three sergestids were the main species from the waters around the archipelago. These results suggest that St Paul`s Rocks can be divided into two habitats, based on larval composition, density and diversity values: the inlet and the waters surrounding the archipelago.

Signaling Events During Cyclic Guanosine Monophosphate-Regulated Pigment Aggregation in Freshwater Shrimp Chromatophores

Crustacean color change results partly from granule aggregation induced by red pigment concentrating hormone (RPCH). In shrimp chromatophores, both the cyclic GMP (3', 5'-guanosine monophosphate) and Ca2+ cascades mediate pigment aggregation. However, the signaling elements upstream and downstream from cGMP synthesis by GC-S (cytosolic guanylyl cyclase) remain obscure. We investigate post-RPCH binding events in perfused red ovarian chromatophores to disclose the steps modulating cGMP concentration, which regulates granule translocation. The inhibition of calcium/calmodulin complex (Ca2+/CaM) by N-(6-aminohexyl)-5-chloro-1-naphthalenesulphonamide (W7) induces spontaneous aggregation but inhibits RPCH-triggered aggregation, suggesting a role in pigment aggregation and dispersion. Nitric oxide synthase inhibition by N omega-nitro-L-arginine methyl ester hydrochloride (L-NAME) strongly diminishes RPCH-induced aggregation; protein kinase G inhibition (by rp-cGMPs-triethylamine) reduces RPCH-triggered aggregation and provokes spontaneous dispersion, disclosing NO/PKG participation in aggregation signaling. Myosin light chain phosphatase inhibition (by cantharidin) accelerates RPCH-triggered aggregation, whereas Rho-associated protein kinase inhibition (by Y-27632, H-11522) reduces RPCH-induced aggregation and accelerates dispersion. MLCP (myosin light chain kinase) and ROCK (Rho-associated protein kinase) may antagonistically regulate myosin light chain (MLC) dephosphorylation/phosphorylation during pigment dispersion/aggregation. We propose the following general hypothesis for the cGMP/Ca2+ cascades that regulate pigment aggregation in crustacean chromatophores: RPCH binding increases Ca2+ (int), activating the Ca2+/CaM complex, releasing NOS-produced nitric oxide, and causing GC-S to synthesize cGMP that activates PKG, which phosphorylates an MLC activation site. Myosin motor activity is initiated by phosphorylation of an MLC regulatory site by ROCK activity and terminated by MLCP-mediated dephosphorylation. Qualitative comparison reveals that this signaling pathway is conserved in vertebrate and invertebrate chromatophores alike.

Alien shrimps in evidence: new records of the genus Athanas Leach, 1814 on the coast of So Paulo, southern Brazil (Caridea: Alpheidae)

The occurrence of two alien alpheid shrimps of the genus Athanas Leach, 1814 [in Leach 1813-1814], the Indo-West Pacific A. dimorphus Ortmann, 1894 and the Eastern Atlantic A. nitescens (Leach, 1813 [in Leach 1813-1814]), on the coast of the state of So Paulo, Brazil, is reported. The presence of A. dimorphus extends the range of this species in the western Atlantic farther to the south in Brazil, whereas A. nitescens is reported for the first time in the western Atlantic, representing the second alien alpheid species on this side of the Atlantic and the twenty-first decapod crustacean introduced in Brazil. We provide morphological accounts of the material examined and illustrate the most important diagnostic characters of both species. An overview of the possible mechanisms of their introduction on the coast of So Paulo is also provided.

Ontogenetic and evolutionary change of external morphology of the neotropical shrimp potimirim (Holthuis, 1954) explained by a molecular phylogeny of the genus

A phylogenetic analysis of a fragment of the mitochondrial gene 16S was used to test the monophyletic status of Potimirim. Existing doubts on the taxonomic status of brasiliana (once P glabra) and P potimirim (once P mexicana) were clarified. Potimirim mexicana and P potimirim are distinct species according to molecular data and appendix masculina morphology. A new species (Potimirim sp. 1) from Puerto Rico was revealed with molecular data, and it is evolutionarily related to P potimirim and P mexicana according to our analysis. We found out three distinct species under the name P glabra. Then, we recommend the application of the name P glabra for the populations of the Pacific slope of Central America and revalidation of P brasiliana for the Brazilian ones. The need for a new name to those "P glabra" of the Caribbean is highlighted, and it was provisionally referred as Potimirim sp. 2. The ontogenetic (juveniles to adults) development of the appendix masculina of P brasiliana was observed and compared to the other species of Potimirim (adults). In the light of our phylogenetic hypothesis, we postulate a pattern of character addition for the evolution of the appendix masculina of Potimirim. This hypothesis is plausible for two key reasons. First. Potimirim is a monophyletic group according to our hypothesis. Second, the shape of appendix masculina found in adults of P. americana is similar and comparable to those found in the earliest juvenile stages of P brasiliana, a derived species according to our phylogeny (P americana, ((P mexicana, Potimirim sp. 1. P potimirim), (P glabra, (brasiliana, Potimirim sp. 2)))). As so, the basal P americana retain the ancestral morphological state of the appendix masculina when compared to the other species of Potimirim. In our interpretation the ontogeny of the appendix masculina recapitulated the proposed phylogeny, giving further support to it.

Composition and Seasonal Variation of Brachyura and Anomura (Crustacea, Decapoda) Associated with Brown Mussel Farms at Praia da Cocanha, Brazil

The composition and seasonal variation of brachyuran and anomuran species associated with mussel farms were evaluated at Praia da Cocanha, Sao Paulo between May 2007 and February 2008. Nine mussel ropes were sampled at random in each quarter, and 1,208 organisms were identified, comprising five families and 28 species. The most numerous species was the porcellanid Pachycheles laevidactylus (18.5%), followed by the xanthids Acantholobulus schmitti (16.6%), Hexapanopeus paulensis (11.3%), Panopeus americanus (10.2%), and Menippe nodifrons (8.4%). The exotic crab Charybdis hellerii was recorded throughout the study period. The ecological descriptors, except Pielou evenness index, varied significantly over the time. The highest abundance and diversity of the species were recorded during November and February. This pattern was reversed for Berger-Parker dominance, with the lowest values recorded in February. The development of epifauna was correlated with the different stages of the mussel farms, since the mean size of mussels and consequently the abundance of epibiotic organisms and the structural complexity on the mussel ropes increased from May (seeding) until February (harvest). Despite this, the temporal population variations in recruitment patterns of the different epibionts should not be overlooked. The results indicated that the mussel farms provided favorable conditions for the development of these crustacean groups, which could be used in environmental monitoring programs and / or be exploited for the aquarium trade.

Composition and seasonal variation of brachyura and anomura (Crustacea, Decapoda) associated with brown mussel farms at Praia da Cocanha, Brazil

The composition and seasonal variation of brachyuran and anomuran species associated with mussel farms were evaluated at Praia da Cocanha, São Paulo between May 2007 and February 2008. Nine mussel ropes were sampled at random in each quarter, and 1,208 organisms were identified, comprising five families and 28 species. The most numerous species was the porcellanid Pachycheles laevidactylus (18.5%), followed by the xanthids Acantholobulus schmitti (16.6%), Hexapanopeus paulensis (11.3%), Panopeus americanus (10.2%), and Menippe nodifrons (8.4%). The exotic crab Charybdis hellerii was recorded throughout the study period. The ecological descriptors, except Pielou evenness index, varied significantly over the time. The highest abundance and diversity of the species were recorded during November and February. This pattern was reversed for Berger-Parker dominance, with the lowest values recorded in February. The development of epifauna was correlated with the different stages of the mussel farms, since the mean size of mussels and consequently the abundance of epibiotic organisms and the structural complexity on the mussel ropes increased from May (seeding) until February (harvest). Despite this, the temporal population variations in recruitment patterns of the different epibionts should not be overlooked. The results indicated that the mussel farms provided favorable conditions for the development of these crustacean groups, which could be used in environmental monitoring programs and / or be exploited for the aquarium trade.