Lack of COI variation for Clavelina oblonga (Tunicata, Ascidiacea) in Brazil: Evidence for its human-mediated transportation?

Recent studies indicate that ascidians are efficiently dispersed by human transport. We have chosen the mitochondrial gene cytochrome c oxidase subunit I (COI) to address whether Clavelina oblonga is an introduced species in the Brazilian coast. Colonies of C. oblonga were sampled in different localities along Atlantic coasts of USA, Panama, and Brazil. The sequencing of 92 colonies resulted in three haplotypes for the species, two unique to Florida and the other shared by exemplars collected in Brazil and Panama; the latter haplotype is identical to the published sequence of Azores. Our evidence, including the absence of C. oblonga in the country's northern tropical waters, its association with artificial habitats and lack of COI variation suggest that the species has been introduced in the southeastern and southern Brazilian coasts. Previous records (85 years old) suggest that it could be a relatively long-term introduction.

Spatial distribution patterns of ascidians (Ascidiacea: Tunicata) in combination with information on bathymetry, oceanography, chlorophyll-a, and sea-ice on the continental shelves off the northern Antarctic Peninsula during POLARSTERN cruise ANT-XXIX/3

Ascidians (Ascidiacea: Tunicata) are sessile suspension feeders that represent dominant epifaunal components of the Southern Ocean shelf benthos and play a significant role in the pelagic-benthic coupling. Here, we report the results of a first study on the relationship between the distribution patterns of eight common and/or abundant (putative) ascidian species, and environmental drivers in the waters off the northern Antarctic Peninsula. During RV Polarstern cruise XXIX/3 (PS81) in January-March 2013, we used seabed imaging surveys along 28 photographic transects of 2 km length each at water depths from 70 to 770 m in three regions (northwestern Weddell Sea, southern Bransfield Strait and southern Drake Passage), differing in their general environmental setting, primarily oceanographic characteristics and sea-ice dynamics, to comparatively analyze the spatial patterns in the abundance of the selected ascidians, reliably to be identified in the photographs, at three nested spatial scales. At a regional (100-km) scale, the ascidian assemblages of the Weddell Sea differed significantly from those of the other two regions, whereas at an intermediate 10-km scale no such differences were detected among habitat types (bank, upper slope, slope, deep/canyon) on the shelf and at the shelf break within each region. These spatial patterns were superimposed by a marked small-scale (10-m) patchiness of ascidian distribution within the 2-km-long transects. Among the environmental variables considered in our study, a combination of water-mass characteristics, sea-ice dynamics (approximated by 5-year averages in sea-ice cover in the region of or surrounding the photographic stations), as well as the seabed ruggedness, was identified as explaining best the distribution patterns of the ascidians.

Contrasting global genetic patterns in two biologically similar, widespread and invasive Ciona species (Tunicata, Ascidiacea)

Human-mediated dispersal interplays with natural processes and complicates understanding of the biogeographical history of species. This is exemplified by two invasive tunicates, Ciona robusta (formerly Ciona intestinalis type A) and C. intestinalis (formerly Ciona intestinalis type B), globally distributed and sympatric in Europe. By gathering new mitochondrial sequences that were merged with published datasets, we analysed genetic patterns in different regions, with a focus on 1) their sympatric range and 2) allopatric populations in N and S America and southern Europe. In the sympatric range, the two species display contrasting genetic diversity patterns, with low polymorphism in C. robusta supporting the prevalent view of its recent introduction. In the E Pacific, several genetic traits support the non-native status of C. robusta. However, in the NE Pacific, this appraisal requires a complex scenario of introduction and should be further examined supported by extensive sampling efforts in the NW Pacific (putative native range). For C. intestinalis, Bayesian analysis suggested a natural amphi-North Atlantic distribution, casting doubt on its non-native status in the NW Atlantic. This study shows that both natural and human-mediated dispersal have influenced genetic patterns at broad scales; this interaction lessens our ability to confidently ascertain native vs. non-native status of populations, particularly of those species that are globally distributed.

Contrasting global genetic patterns in two biologically similar, widespread and invasive Ciona species (Tunicata, Ascidiacea)

Human-mediated dispersal interplays with natural processes and complicates understanding of the biogeographical history of species. This is exemplified by two invasive tunicates, Ciona robusta (formerly Ciona intestinalis type A) and C. intestinalis (formerly Ciona intestinalis type B), globally distributed and sympatric in Europe. By gathering new mitochondrial sequences that were merged with published datasets, we analysed genetic patterns in different regions, with a focus on 1) their sympatric range and 2) allopatric populations in N and S America and southern Europe. In the sympatric range, the two species display contrasting genetic diversity patterns, with low polymorphism in C. robusta supporting the prevalent view of its recent introduction. In the E Pacific, several genetic traits support the non-native status of C. robusta. However, in the NE Pacific, this appraisal requires a complex scenario of introduction and should be further examined supported by extensive sampling efforts in the NW Pacific (putative native range). For C. intestinalis, Bayesian analysis suggested a natural amphi-North Atlantic distribution, casting doubt on its non-native status in the NW Atlantic. This study shows that both natural and human-mediated dispersal have influenced genetic patterns at broad scales; this interaction lessens our ability to confidently ascertain native vs. non-native status of populations, particularly of those species that are globally distributed.

PEPTIDES RELATED TO THE DIPLOPTERA-PUNCTATA ALLATOSTATINS IN NONARTHROPOD INVERTEBRATES - AN IMMUNOCYTOCHEMICAL SURVEY

The allatostatins are a family of peptides isolated originally from the cockroach, Diploptera punctata. Related peptides have been identified in Periplaneta americana and the blowfly, Calliphora vomitoria. These peptides have been shown to be potent inhibitors of juvenile hormone synthesis in these species. A peptide inhibitor of juvenile hormone biosynthesis has also been isolated from the moth, Manduca sexta; however, this peptide has no structural homology with the D. punctata-type allatostatins. Investigations of the phylogeny of the D. punctata allatostatin peptide family have been started by examining a number of nonarthropod invertebrates for the presence of allatostatin-like molecules using immunocytochemistry with antisera directed against the conserved C-terminal region of this family. Allatostatin-like immunoreactivity (ALIR) was demonstrated in the nervous systems of Hydra oligactis (Hydrozoa), Moniezia expansa (Cestoda), Schistosoma mansoni (Trematoda), Artioposthia triangulata (Turbellaria), Ascaris suum (Nematoda), Lumbricus terrestris (Oligochaeta), Limax pseudoflavus (Gastropoda), and Eledone cirrhosa (Cephalopoda). ALIR could not be demonstrated in Ciona intestinalis (Ascidiacea). These results suggest that molecules related to the allatostatins may play an important role in nervous system function in many invertebrates as well as in insects and that they also have an ancient evolutionary lineage. (C) 1994 Wiley-Liss, Inc.

Systematic UPLC-ESI-MS/MS Study on the Occurrence of Staurosporine and Derivatives in Associated Marine Microorganisms from Eudistoma vannamei

Former bioactivity-guided analysis of the marine invertebrate Eudistoma vannamei led to the isolation of staurosporine derivatives, which revealed strong cytotoxic activity against several human cancer cell lines. The occurrence of such alkaloids in E. vannamei may be correlated to the presence of associated biota, such as Streptomyces bacteria. In agreement to this hypothesis, marine microorganisms associated with E. vannamei were recovered and cultured, leading to a total of 84 isolated bacterial strains. Gas phase fragmentation reactions of staurosporine and derivatives were systematically studied and the analyzed results further supported by computational chemistry studies. The resulting fragment patterns were used to search for the presence of different derivatives in extracts of isolated microorganisms, thereby using LC-MS/MS analysis in MRM mode. These results evidenced that one isolated Streptomyces sp. was able to generate staurosporine, while none of the hydroxy-7-oxo derivatives were detected. Finally, significant cytotoxic activity against human cancer lines was observed for one of the extracts.

Rapid assessment survey for exotic benthic species in the São Sebastião Channel, Brazil

The study of biological invasions can be roughly divided into three parts: detection, monitoring, mitigation. Here, our objectives were to describe the marine fauna of the area of the port of São Sebastião (on the northern coast of the state of São Paulo, in the São Sebastião Channel, SSC) to detect introduced species. Descriptions of the faunal community of the SSC with respect to native and allochthonous (invasive or potentially so) diversity are lacking for all invertebrate groups. Sampling was carried out by specialists within each taxonomic group, in December 2009, following the protocol of the Rapid Assessment Survey (RAS) in three areas with artificial structures as substrates. A total of 142 species were identified (61 native, 15 introduced, 62 cryptogenic, 4 not classified), of which 17 were Polychaeta (12, 1, 1, 3), 24 Ascidiacea (3, 6, 15, 0), 36 Bryozoa (17, 0, 18, 1), 27 Cmdana (2, 1, 24, 0), 20 Crustacea (11, 4, 5, 0), 2 Entoprocta (native), 16 Mollusca (13, 3, 0, 0). Twelve species are new occurrences for the SSC. Among the introduced taxa, two are new for coastal Brazil. Estimates of introduced taxa are conservative as the results of molecular studies suggest that some species previously considered cryptogenic are indeed introduced. We emphasize that the large number of cryptogenic species illustrates the need for a long-term monitoring program, especially in areas most susceptible to bioinvasion. We conclude that rapid assessment studies, even in relatively well-known regions, can be very useful for the detection of introduced species and we recommend that they be carried out on a larger scale in all ports with heavy ship traffic.