Diversification and Species Boundaries of Rhinebothrium (Cestoda; Rhinebothriidea) in South American Freshwater Stingrays (Batoidea; Potamotrygonidae)

Background: Neotropical freshwater stingrays (Batoidea: Potamotrygonidae) host a diverse parasite fauna, including cestodes. Both cestodes and their stingray hosts are marine-derived, but the taxonomy of this host/parasite system is poorly understood. Methodology: Morphological and molecular (Cytochrome oxidase I) data were used to investigate diversity in freshwater lineages of the cestode genus Rhinebothrium Linton, 1890. Results were based on a phylogenetic hypothesis for 74 COI sequences and morphological analysis of over 400 specimens. Cestodes studied were obtained from 888 individual potamotrygonids, representing 14 recognized and 18 potentially undescribed species from most river systems of South America. Results: Morphological species boundaries were based mainly on microthrix characters observed with scanning electron microscopy, and were supported by COI data. Four species were recognized, including two redescribed (Rhinebothrium copianullum and R. paratrygoni), and two newly described (R. brooksi n. sp. and R. fulbrighti n. sp.). Rhinebothrium paranaensis Menoret & Ivanov, 2009 is considered a junior synonym of R. paratrygoni because the morphological features of the two species overlap substantially. The diagnosis of Rhinebothrium Linton, 1890 is emended to accommodate the presence of marginal longitudinal septa observed in R. copianullum and R. brooksi n. sp. Patterns of host specificity and distribution ranged from use of few host species in few river basins, to use of as many as eight host species in multiple river basins. Significance: The level of intra-specific morphological variation observed in features such as total length and number of proglottids is unparalleled among other elasmobranch cestodes. This is attributed to the large representation of host and biogeographical samples. It is unclear whether the intra-specific morphological variation observed is unique to this freshwater system. Nonetheless, caution is urged when using morphological discontinuities to delimit elasmobranch cestode species because the amount of variation encountered is highly dependent on sample size and/or biogeographical representation.

Meiobenthic community underneath the carcass of a stingray: a snapshot after natural death

The impact of large food falls and carrion on meiobenthic communities remains little understood. The objective of the present study was to investigate whether the carcass of a stingray, encountered fortuitously in an Australian estuary, affects the underlying meiobenthic community, in particular nematode assemblages. The integrity of the skeleton and the low redox values observed under the carcass suggest that the cadaver had been slowly and chiefly decomposed by microbes. The abundance and number of meiofaunal taxa, as well as nematode abundance and nematode-species richness, were significantly lower under the carcass when compared to samples outside the carcass. Nonetheless, a few nematode species, typical of hypoxic/anoxic sediments, were more abundant under the carcass. Interestingly, all these species were absent or rare in samples near, but not under, the carcass, suggesting that they may take advantage of the reduced environment created by the carcass and the consequent lack of competition to prosper. As observed for other marine environments, carcasses in estuaries create a microhabitat that supports a characteristic meiobenthic fauna, distinct from those inhabiting the surrounding sediments, but similar to those of reduced habitats.

Meiobenthic communities of seagrass beds (Zostera capricorni) and unvegetated sediments along the coast of New South Wales, Australia

Seagrass beds have higher biomass, abundance, diversity and productivity of benthic organisms than unvegetated sediments. However, to date most studies have analysed only the macrofaunal component and ignored the abundant meiofauna present in seagrass meadows. This study was designed to test if meiobenthic communities, especially the free-living nematodes, differed between seagrass beds and unvegetated sediments. Sediment samples from beds of the eelgrass Zostera capricorni and nearby unvegetated sediments were collected in three estuaries along the coast of New South Wales, Australia. Results showed that sediments below the seagrass were finer, with a higher content of organic material and were less oxygenated than sediments without seagrass. Univariate measures of the fauna (i.e. abundance, diversity and taxa richness of total meiofauna and nematode assemblages) did not differ between vegetated and unvegetated sediments. However multivariate analysis of meiofaunal higher taxa showed significant differences between the two habitats, largely due to the presence and absence of certain taxa. Amphipods, tanaidacea, ostracods, hydrozoans and isopods occurred mainly in unvegetated sediments, while kinorhyncs, polychaetes, gastrotrichs and turbellarians were more abundant in vegetated sediments. Regarding the nematode assemblages, 32.4% of the species were restricted to Z. capricorni and 25% only occurred in unvegetated sediments, this suggests that each habitat is characterized by a particular suite of species. Epistrate feeding nematodes were more abundant in seagrass beds, and it is suggested that they graze on the microphytobenthos which accumulates underneath the seagrass. Most of the genera that characterized these estuarine unvegetated sediments are also commonly found on exposed sandy beaches. This may be explained by the fact that Australian estuaries have very little input of freshwater and experience marine conditions for most of the year. This study demonstrates that the seagrass and unvegetated sediments have discrete meiofaunal communities, with little overlap in species composition. (C) 2010 Elsevier Ltd. All rights reserved.

Diversity of free-living marine nematodes (Enoplida) from Baja California assessed by integrative taxonomy

We used morphological and molecular approaches to evaluate the diversity of free-living marine nematodes (order Enoplida) at four coastal sites in the Gulf of California and three on the Pacific coast of Baja California, Mexico. We identified 22 morphological species belonging to six families, of which Thoracostomopsidae and Oncholaimidae were the most diverse. The genus Mesacanthion (Thoracostomopsidae) was the most widespread and diverse. Five allopatric species, genetically and morphologically differentiated, were found in two localities in the Gulf of California (M. sp1 and M. sp2) and three in the Pacific coast (M. sp3, M. sp4 and M. sp5). Overall, we produced 19 and 20 sequences for the 18S and 28S genes, respectively. Neither gene displayed intraspecific polymorphisms, which allowed us to establish that some morphological variation was likely either ontogenetic or due to phenotypic plasticity. Although 18S and 28S phylogenies were topologically congruent (incongruence length difference test, P > 0.05), divergences between species were much higher in the 28S gene. Moreover, this gene possessed a stronger phylogenetic signal to resolve relationships involving Rhabdodemania and Bathylaimus. On the other hand, the close relationship of Pareurystomina (Enchilidiidae) with oncholaimids warrants further study. The 28S sequences (D2D3 domain) may be better suited for DNA barcoding of marine nematodes than those from the 18S rDNA, particularly for differentiating closely related or cryptic species. Finally, our results underline the relevance of adopting an integrative approach encompassing morphological and molecular analyses to improve the assessment of marine nematode diversity and advance their taxonomy.

A sampling device to quantify offspring release of sessile marine invertebrates

Quantifying the rate of propagule release is of most importance to estimate reproductive output of natural populations, but simple methods to obtain such data are seldom reported. We designed and tested an inexpensive apparatus capable of reliably measure the release of gametes, eggs or larvae of sessile marine invertebrates in vertical walls. A population of the acom barnacle Chthamalus bisinuatus was sampled with this trap over 68d to obtain a time series of naupliar release. An apparent semilunar trend is shown, indicating the effectiveness of this sampling method.

Influence of the slice position on chloride migration tests for concrete in marine conditions

Chloride migration tests are used to measure the concrete capacity to inhibit chloride attack. Many researchers carry out this test in a slice of concrete extracted from the central part of cylindrical specimens, discarding about 75% of the concrete used to mold the specimens. This fact generated the question: would it be possible to extract more slices from a same specimen without losing the confidence in the results? The main purpose of this work is to answer this question. Moreover, another aim of this study was to show the difference of chloride penetration between finished faces and the formwork surfaces of concrete beams and slabs. The results indicated that it is possible to use more slices of a single specimen for a chloride migration test. Moreover, it was demonstrated that there is a significant difference of chloride penetration between the finished surface and the formwork surface of the specimens. (C) 2008 Elsevier Ltd. All rights reserved.

Surface treatment of reinforced concrete in marine environment: Influence on chloride diffusion coefficient and capillary water absorption

There are currently many types of protective materials for reinforced concrete structures and the influence of these materials in the chloride diffusion coefficient still needs more research. The aim of this paper is to study the efficacy of certain surface treatments (such as hydrophobic agents, acrylic coating, polyurethane coating and double systems) in inhibiting chloride penetration in concrete. The results indicated that all tested surface protection significantly reduced the sorptivity of concrete (reduction rate > 70%). However, only the polyurethane coating was highly effective in reducing the chloride diffusion coefficient (reduction rate of 86%). (C) 2008 Elsevier Ltd. All rights reserved.

Exploration of the acarine fauna on coconut palm in Brazil with emphasis on Aceria guerreronis (Acari : Eriophyidae) and its natural enemies

Coconut is an important crop in tropical and subtropical regions. Among the mites that infest coconut palms, Aceria guerreronis Keifer is economically the most important. We conducted surveys throughout the coconut growing areas of Brazil. Samples were taken from attached coconuts, leaflets, fallen coconuts and inflorescences of coconut palms in 112 localities aiming to determine the Occurrence and the distribution of phytophagous mites, particularly A. guerreronis, and associated natural enemies. Aceria guerreronis was the most abundant phytophagous mite followed by Steneotarsonemus concavuscutum Lofego & Gondim Jr. and Steneotarsonemus furcatus De Leon (Tarsonemidae). Infestation by A. guerreronis was recorded in 87% of the visited localities. About 81% of all predatory mites belonged to the family Phytoseiidae, mainly represented by Neoseiulus paspalivorus De Leon, Neoseiulus baraki Athias-Henriot and Amblyseius largoensis Muma; 12% were Ascidae, mainly Proctolaelaps bickleyi Bram, Proctolaelaps sp nov and Lasioseius subterraneus Chant. Neoseiulus paspalivorus and N. baraki were the most abundant predators on attached coconuts. Ascidae were predominant on fallen coconuts, while A. largoensis was predominant on leaflets; no mites were found on branches of inflorescences. Leaflets harboured higher mite diversity than the attached coconuts. Mite diversity was the highest in the state Para and on palms surrounded by seasonal forests and Amazonian rain-forests. Neoseiulus paspalivorus, N. baraki and P. bickleyi were identified as the most promising predators of A. guerreronis. Analyses of the influence of climatic factors revealed that dry ambient conditions favour the establishment of A. guerreronis. Neoseiulus paspalivorus and N. baraki have differing climatic requirements; the former being more abundant in warm and dry areas, the latter prevailing ill moderately tempered and humid areas. We discuss the significance of our findings for natural and biological control of A. guerreronis.

Fauna of plant-parasitic nematodes in natural and cultivated areas of the Amazon forest, Mato Grosso State, Brazil

The aim of this work was to study the diversity of the fauna of plant-parasitic nematodes in preserved areas of the Amazon forest, Mato Grosso state (MT), and to assess the effect of agricultural land use on plant-parasitic nematode communities. Soil and root samples were collected in each location in the late spring during the rainy season of 2005, in two areas of primary vegetation in Nova Maringa (Northwest) and Guaranta do Norte (North) and two adjacent areas planted with teak trees (Tectona grandis) and pasture (Brachiaria brizantha). Four-teen taxa of plant-parasitic nematodes were identified at species level: Discocriconemella degrissei, D. limitanea, Dolichodorus minor, Helicotylenchus erythrinae, H. pseudorobustus, Meloidogyne exigua, M javanica, Mesocriconema ornata, Paratrichodorus minor, Pratylenchus loosi, P zeae, Rotylenchus caudaphasmidius, Xiphinema ensiculiferum and X luci (for the first report of this in Brazil) and five at genus level (Atalodera sp., Hemicriconemoides sp., Meloidogyne sp., Paratylenchus sp., and Trophotylenchulus sp). These taxa, mainly those from primary vegetation, belong to families with different parasitic behavior, probably due to great plant diversity in the Amazon forest. Comparison between the two preserved areas revealed low index of similarity, as a consequence of the endemic flora in the Amazon forest, and no similarity was observed between preserved native vegetation and adjacent cultivated areas, demonstrating the high influence of agricultural activity on the plant-parasitic nematode communities. There is evidence of recent introduction of plant-parasitic nematodes in these cultivated areas; therefore measures should be taken to prevent the loss of economic sustainability in Amazonian soils. Keywords: abundance, Amazonia, diversity, Brachiaria brizantha, plant-parasitic nematode fauna, Tectona grandis.

Trypanocidal, leislimanicidal and antifungal potential from marine red alga Bostrychia tenella J. Agardli (Rhodomelaceae, Ceraniiales)

Specimens of the red alga Bostrychia tenella J Agardh (Rhodomelaceae, Ceramiales) were collected from the Sao Paulo coast and submitted to loom temperature solvent extraction The resulting extract was fractionated by partitioning with organic solvent The n-hexane (BT-H) and dichloromethane (BT-D) fractions showed antiprotozoal potential in biological tests with Trypanosoma cruzi and Leishmania amazonensis and presented high activity in an antifungal assay with the phytopathogenic fungi Cladosporium cladosporioides and Cladosporium sphaerospermum Chromatography methods were used to generate subfractions from BT-H (H01 to H11) and from BT-D (D01 to 019) The subtractions were analyzed by gas chromatography-mass spectrometry (GC/MS). and the substances were identified by retention index (Kovats) and by comparison to databases of commercial mass spectra The volatile compounds found in marine algae were identified as fatty acids, low molecular mass hydrocarbons, esters and steroids, some of these have been previously described in the literature based on other biological activities Moreover, uncommon substances. such as neophytadiene were also identified In a trypanocidal assay, fractions BT-H and BT-D showed IC(50) values of 168 and 19 1 mu g/mL. respectively, and were mote active than the gentian violet standard (31 mu g/ml.); subfractions H02. H03, D01 and D02 were active against L amasonensis, exhibiting IC(50) values of 1 S. 2 7, 4 4. and 4 3 mu g/mL., respectively (standard amphotericin B IC(50) = 13 mu g/mL.) All fractions showed antifungal potential this work reports the biological activity and identification of compounds by GC/MS for the marine red alga B tenella for the first time (C) 2010 Elsevier B V All lights reserved

Bioreduction of Acetophenone Derivatives by Red Marine Algae Bostrychia radicans and B. tenella, and Marine Bacteria Associated

The biocatalytic reduction of acetophenone derivatives was exploited by using algal biomass from Bostrychia radicans and B. tenella producing exclusively (S)-2-phenylethanols with high enantiomeric excess (> 99% ee). Bacterial populations associated with algal biomass were identified as the Bacillus genus. This report deals with the first investigations involving the use of marine bacteria associated with B. radicans and B. tenella marine algae for the biocatalytic reduction of acetophenone derivatives.

Effects of pasture implantation on the termite (Isoptera) fauna in the Central Brazilian Savanna (Cerrado)

The advance of agricultural frontier may cause the Cerrado (Brazilian savanna) to disappear before 2030. This work focuses on measuring the impact of pasture implantation on a cerrado`s termite fauna. Termites were sampled in a cerrado sensu stricto and a pasture, originally cerrado. All species were classified as their feeder group, accumulation curves were made and Shannon-Wiener indexes and beta diversity were calculated for both areas. Cerrado was richer than pasture and species composition differed considerably, leading beta diversity to a high value. The humivorous was the most representative species, followed by grass/litter feeders, xylophagous and, less representative, the intermediates. There were more xylophagous and intermediates species on cerrado than in pasture; the grass/litter feeders were more abundant in pasture, but didn`t differed in number or species; and humivorous didn`t differed neither in richness nor in abundance. This work shows that the simplification of the habitat is indeed causing the extinction of populations that depend on some specifics resource.

Evolutionary transition to freshwater by ancestral marine palaemonids: evidence from osmoregulation in a tide pool shrimp

The transition from marine/brackish waters to freshwater habitats constitutes a severe osmotic and ionic challenge, and successful invasion has demanded the selection of morphological, physiological, biochemical and behavioral adaptations. We evaluated short-term (1 to 12 h exposure) and long-term (5 d acclimation), anisosmotic extracellular (osmolality, [Na(+), Cl(-)]) and long-term isosmotic intracellular osmoregulatory capability in Palaemon northropi, a neotropical intertidal shrimp. F northropi survives well and osmo- and ionoregulates strongly during short- and long-term exposure to 5-45 parts per thousand salinity, consistent with its rocky tide pool habitat subject to cyclic salinity fluctuations, Muscle total free amino acid (FAA) concentrations decreased by 63% in shrimp acclimated to 5%. salinity, revealing a role in hypoosmotic cell volume regulation; this decrease is mainly a consequence of diminished glycine, arginine and proline. Total FAA contributed 31% to muscle intracellular osmolality at 20 parts per thousand, an isosmotic salinity, and decreased to 13% after acclimation to 5 parts per thousand. Gill and nerve tissue FAA concentrations remained unaltered. These tissue-specific responses reflect efficient anisosmotic and anisoionic extracellular regulatory mechanisms, and reveal the dependence of muscle tissue on intracellular osmotic effectors. FAA concentration is higher in P. northropi than in diadromous and hololimnetic palaemonids, confirming muscle FAA concentration as a good parameter to evaluate the degree of adaptation to dilute media. The osmoregulatory capability of P. northropi may reflect the potential physiological capacity of ancestral marine palaemonids to penetrate into dilute media, and reveals the importance of evaluating osmoregulatory processes in endeavors to comprehend the invasion of dilute media by ancestral marine crustaceans.

Agglutinin isolated from the red marine alga Hypnea cervicornis J. Agardh reduces inflammatory hypernociception: Involvement of nitric oxide

Hypnea cervicornis agglutinin (HCA), a lectin isolated from the red marine alga has been previously shown to have an antinociceptive effect. In the present study in rats, mechanisms of action of HCA were addressed regarding mechanical hypernociception induced by carrageenan, ovalbumin (as antigen), and also by prostaglandin E(2) in rats. The lectin administered intravenously inhibited carrageenan- and antigen-induced hypernociception at 1,3, 5 and 7 h. This inhibitory effect was completely prevented when lectin was combined with mucin, demonstrating the role of carbohydrate-binding sites. The inhibition of inflammatory hypernociception by HCA was associated with the prevention of neutrophil recruitment to the plantar tissue of rats but was not associated with the inhibition of the release of pro-hypernociceptive cytokines (TNF-alpha, IL-1 beta and CINC-1). HCA also blocked mechanical hypernociception induced by PGE(2), which was prevented by the administration of nitric oxide synthase inhibitors. These results were corroborated by the increased circulating levels of NO metabolites following HCA treatment. These findings suggest that the anti-hypernociceptive effects of HCA are not associated with the inhibition of pro-inflammatory cytokine production. However, these effects seem to involve the inhibition of neutrophil migration and also the increase in NO production. (C) 2010 Elsevier Inc. All rights reserved.

Analysis of marine bivalve shellfish from the fish market in Santos city, Sao Paulo state, Brazil, for Toxoplasma gondii

The aim of this study was to determine if Toxoplasma gondii are present in oysters (Crassostrea rhizophorae) and mussels (Mytella guyanensis) under natural conditions using a bioassay in mice and molecular detection methods. We first compared two standard protocols for DNA extraction, phenol-chloroform (PC) and guanidine-thiocyanate (GT), for both molluscs. A total of 300 oysters and 300 mussels were then acquired from the fish market in Santos city, Sao Paulo state, Brazil, between March and August of 2008 and divided into 60 groups of 5 oysters and 20 groups of 15 mussels. To isolate the parasite, five mice were orally inoculated with sieved tissue homogenates from each group of oysters or mussels. For molecular detection of T. gondii, DNA from mussels was extracted using the PC method and DNA from oysters was extracted using the GT method. A nested-PCR (Polymerase Chain Reaction) based on the amplification of a 155 bp fragment from the B1 gene of T. gondii was then performed. Eleven PCR-RFLP (Restriction Fragment Length Polymorphism) markers, SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, CS3 and Apico, were used to genotype positive samples. There was no isolation of the parasite by bioassay in mice. T. gondii was not detected in any of the groups of mussels by nested-PCR. DNA of T. gondii was apparently detected by nested-PCR in 2 groups of oysters (3.3%). Genotyping of these two positive samples was not successful. The results suggest that oysters of the species C. rhizophorae, the most common species from the coast of Sao Paulo, can filter and retain T. gondii oocysts from the marine environment. Ingestion of raw oysters as a potential transmission source of T. gondii to humans and marine mammals should be further investigated. (C) 2010 Elsevier B.V. All rights reserved.