Coldwater reattachment of colonial tunicate Didemnum vexillum fragments to natural (eelgrass) and artificial (plastic) substrates in New England

© The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Aquatic Invasions 9 (2014): 105–110, doi:10.3391/ai.2014.9.1.09.The colonial tunicate Didemnum vexillum Kott, 2002, was introduced to New England in the 1980s and by 2000 it was widespread. This highly invasive species spreads by larval release and fragmentation. We tested the ability of D. vexillum fragments to reattach to natural (eelgrass Zostera marina (Linnaeus, 1753)) and artificial (plastic container) substrates during late fall and early winter. On average, 77% of D. vexillum fragments reattached to eelgrass and plastic in water temperatures between 6 and 10°C. Eelgrass appeared to facilitate D. vexillum reattachment success in early winter but this tendency should be further investigated.Funding to Carman came from the US EPA RARE Program and USGS-WHOI Cooperative Agreement

Species–specific crab predation on the hydrozoan clinging jellyfish Gonionemus sp. (Cnidaria, Hydrozoa), subsequent crab mortality, and possible ecological consequences

© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PeerJ 5 (2017): e3966, doi:10.7717/peerj.3966.Here we report a unique trophic interaction between the cryptogenic and sometimes highly toxic hydrozoan clinging jellyfish Gonionemus sp. and the spider crab Libinia dubia. We assessed species–specific predation on the Gonionemus medusae by crabs found in eelgrass meadows in Massachusetts, USA. The native spider crab species L. dubia consumed Gonionemus medusae, often enthusiastically, but the invasive green crab Carcinus maenus avoided consumption in all trials. One out of two blue crabs (Callinectes sapidus) also consumed Gonionemus, but this species was too rare in our study system to evaluate further. Libinia crabs could consume up to 30 jellyfish, which was the maximum jellyfish density treatment in our experiments, over a 24-hour period. Gonionemus consumption was associated with Libinia mortality. Spider crab mortality increased with Gonionemus consumption, and 100% of spider crabs tested died within 24 h of consuming jellyfish in our maximum jellyfish density containers. As the numbers of Gonionemus medusae used in our experiments likely underestimate the number of medusae that could be encountered by spider crabs over a 24-hour period in the field, we expect that Gonionemus may be having a negative effect on natural Libinia populations. Furthermore, given that Libinia overlaps in habitat and resource use with Carcinus, which avoids Gonionemus consumption, Carcinus populations could be indirectly benefiting from this unusual crab–jellyfish trophic relationship.This work was supported by the Oak Bluffs Community Preservation Committee under Grant 45908900; Oak Bluffs Community Preservation Committee under Grant 45785700; USGS-WHOI Cooperative Program under Grant 48010601, the Adelaide M. and Charles B. Link Foundation, and the Kathleen M. and Peter E. Naktenis Family Foundation

An initial assessment of native and invasive tunicates in shellfish aquaculture of the North American east coast

Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Journal of Applied Ichthyology 26, Supple.s2 (2010): 8-11, doi:10.1111/j.1439-0426.2010.01495.x.The objective of the study was to assess the distribution of native and invasive tunicates in the fouling community of shellfish aquaculture gear along the U.S. east coast of the Atlantic. Since the 1980s, several species of invasive tunicates have spread throughout the coastal waters of the North American east coast and have become dominant fouling organisms on docks, boat hulls, mooring lines, and in shellfish aquaculture. Invasive and native tunicates negatively impact shellfish aquaculture through increased maintenance costs and reduced shellfish growth. While the presence of alien tunicates has been well documented at piers, harbors, and marinas, there are few published reports of invasive tunicate impacts to aquaculture. We surveyed shellfish aquaculture operations at Martha’s Vineyard, Massachusetts and shellfish aquaculturists in other areas along the North American east coast and report high levels of fouling caused by seven invasive, three native, and two cryptogenic species of tunicates. All study sites were fouled by one or more tunicate species. Biofouling control treatments varied among aquaculture sites and were effective in removing tunicates. Invasive and native tunicates should be considered when assessing the economic impacts of fouling organisms to the aquaculture industry.This work was funded in part by Sailors’ Snug Harbor of Boston, the Adelaide and Charles Link Foundation, and the NOAA Aquatic Invasive Species Program

Mitochondrial diversity in Gonionemus (Trachylina:Hydrozoa) and its implications for understanding the origins of clinging jellyfish in the Northwest Atlantic Ocean

© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PeerJ 5 (2017): e3205, doi:10.7717/peerj.3205.Determining whether a population is introduced or native to a region can be challenging due to inadequate taxonomy, the presence of cryptic lineages, and poor historical documentation. For taxa with resting stages that bloom episodically, determining origin can be especially challenging as an environmentally-triggered abrupt appearance of the taxa may be confused with an anthropogenic introduction. Here, we assess diversity in mitochondrial cytochrome oxidase I sequences obtained from multiple Atlantic and Pacific locations, and discuss the implications of our findings for understanding the origin of clinging jellyfish Gonionemus in the Northwest Atlantic. Clinging jellyfish are known for clinging to seagrasses and seaweeds, and have complex life cycles that include resting stages. They are especially notorious as some, although not all, populations are associated with severe sting reactions. The worldwide distribution of Gonionemus has been aptly called a “zoogeographic puzzle” and our results refine rather than resolve the puzzle. We find a relatively deep divergence that may indicate cryptic speciation between Gonionemus from the Northeast Pacific and Northwest Pacific/Northwest Atlantic. Within the Northwest Pacific/Northwest Atlantic clade, we find haplotypes unique to each region. We also find one haplotype that is shared between highly toxic Vladivostok-area populations and some Northwest Atlantic populations. Our results are consistent with multiple scenarios that involve both native and anthropogenic processes. We evaluate each scenario and discuss critical directions for future research, including improving the resolution of population genetic structure, identifying possible lineage admixture, and better characterizing and quantifying the toxicity phenotype.This work was supported by the Woods Hole Sea Grant, the Town of Oak Bluffs Community Preservation Committee, the Nantucket Biodiversity Initiative, the Kathleen M. and Peter E. Naktenis Family Foundation, and the Russian Science Foundation (No. 14-50-00034)

Abundance and diversity of ascidians in the southern Gulf of Chiriquí, Pacific Panama

© The Author(s), 2011. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Aquatic Invasions 6 (2011): 381-390, doi:10.3391/ai.2011.6.4.03.Little is known about the ascidian fauna of Pacific Panama. Ascidian surveys were conducted in the southern Gulf of Chiriquí on the Pacific coast of Panama in January 2008 and 2009. Surveys along linear transects at 2-3 m depth (snorkel, 2008) and 5 and 12 m depth (SCUBA, 2009) were conducted at multiple sites within a chain of islands extending out from the mainland. Twelve different ascidian taxa were observed with mean densities of up to ~17 ascidians m-2. The most abundant species was Rhopalaea birkelandi. Two of the most abundant taxa (Ascidia sp., Pyura sp.) appear to represent previously undescribed species. Several species of didemnids were also abundant. Ascidians were most abundant near the coast of the mainland and were less abundant near the islands farthest offshore. These data on Panamanian ascidian communities provide a baseline of local biodiversity against which it will be possible to determine whether the communities change over time, if additional species become introduced to the region, or if native Panamanian species become invasive in other parts of the world.This research was supported by Ocean Life Institute Exploratory Grant (250513.38) to Carman and Sievert, Tropical Research Initiative Grant (253750.09) to Carman, Molyneaux and Sievert, a University of Hartford International Center Faculty Grant to Bullard, and CNPq senior postdoctoral grant to Rocha (200914/2008-1)

Ascidians at the Pacific and Atlantic entrances to the Panama Canal

© The Author(s), 2011. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Aquatic Invasions 6 (2011): 371-380, doi:10.3391/ai.2011.6.4.02.The Panama Canal region is susceptible to non-native species introductions due to the heavy international shipping traffic through the area. Ascidian introductions are occurring worldwide but little is known about introductions at the Panama Canal. Surveys were conducted in 2002, 2008, and 2009 within the Pacific and Atlantic entrances to the canal. We found a high diversity of ascidians on both sides of the canal, dominated by non-native species; six species occurred at both Pacific and Atlantic Panama sites. This is the first report of Polyandrocarpa anguinea and P. sagamiensis in Atlantic Panama waters and Ascidia incrassata, Ascidia sydneiensis, Botrylloides nigrum, Botryllus planus, Didemnum perlucidum, Diplosoma listerianum, Microcosmus exasperatus, Polyandrocarpa zorritensis, Polyclinum constellatum, Symplegma brakenhielmi, Symplegma rubra, and Trididemnum orbiculatum in Pacific Panama waters. The canal may serve as a major invasion corridor for ascidians and should be monitored over time.Funding for this project came from WHOI Ocean Life Institute-Tropical Research Initiative to Carman and CNPq to Rocha

Fragment reattachment, reproductive status, and health indicators of the invasive colonial tunicate Didemnum vexillum with implications for dispersal

This manuscript is not subject to U.S. copyright. The definitive version was published in Biological Invasions 14 (2012): 2133-2140, doi:10.1007/s10530-012-0219-8.The invasive colonial tunicate Didemnum vexillum is now widespread in coastal and offshore waters of New England, USA. D. vexillum can inflict ecological and economic damage through biofouling and habitat modification. Natural and anthropogenic processes that fragment colonies of D. vexillum may be accelerating the spread of this invader. Reattachment success and fragment viability were confirmed in the laboratory after four weeks of suspension in experimental aquaria. The shape of suspended D. vexillum fragments progressed from flattened to globular spheres and then flattened again after reattachment to the substrate. Reproductive activity, confirmed by the presence of eggs and larvae, was observed for fragments suspended up to three weeks suggesting that D. vexillum is capable of reproducing while in a fragmented, suspended state. An index of colony health was used to monitor change in D. vexillum health while in suspension. Overall, colony health declined with time in suspension although colonies that appeared dead (black and gray in overall color) still contained a substantial number of healthy live zooids. These results suggest that activities that cause fragmentation can significantly facilitate the spread of D. vexillum. Coastal managers should consider reducing or eliminating, when practical, activities that return fragmented colonies of D. vexillum to the water. In-water cleaning of biofouling and dredging are likely expediting the spread of this invasive species unless biofouling can be contained and removed from the water.This research was funded by the NOAA Aquatic Invasive Species Program

The colonial ascidian Didemnum sp. A: Current distribution, basic biology and potential threat to marine communities of the northeast and west coasts of North America

Author Posting. © The Author(s), 2006. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Journal of Experimental Marine Biology and Ecology 342 (2007): 99-108, doi:10.1016/j.jembe.2006.10.020.Didemnum sp. A is a colonial ascidian with rapidly expanding populations on the east and west coasts of North America. The origin of Didemum sp. A is unknown. Populations were first observed on the northeast coast of the U.S. in the late 1980s and on the west coast during the 1990s. It is currently undergoing a massive population explosion and is now a dominant member of many subtidal communities on both coasts. To determine Didemnum sp. A’s current distribution, we conducted surveys from Maine to Virginia on the east coast and from British Columbia to southern California on the west coast of the U.S. between 1998 and 2005. In nearshore locations Didemnum sp. A currently ranges from Eastport, Maine to Shinnecock Bay, New York on the east coast. On the west coast it has been recorded from Humboldt Bay to Port San Luis in California, several sites in Puget Sound, Washington, including a heavily fouled mussel culture facility, and several sites in southwestern British Columbia on and adjacent to oyster and mussel farms. The species also occurs at deeper subtidal sites (up to 81 m) off New England, including Georges, Stellwagen and Tillies Banks. On Georges Bank numerous sites within a 147 km2 area are 50-90% covered by Didemnum sp. A; large colonies cement the pebble gravel into nearly solid mats that may smother infaunal organisms. These observations suggest that Didemnum sp. A has the potential to alter marine communities and affect economically important activities such as fishing and aquaculture.Funding for this project was provided by EPA (STAR) grant GZ1910464 to R.B. Whitlatch, NSF-DGE 0114432 to J. Byrnes, NSF-OCE 0117839 to R. Etter and R.J. Miller, MIT Sea Grant NA86RG0074 and USEPA Grant GX83055701-0 to J. Pederson. RI Sea Grant NA07R90363 to J.S. Collie. Funding for A.N. Cohen and G. Lambert was provided by Mass. Sea Grant, U.S. EPA, Smithsonian Envl. Research Center Invasions Lab, Natl. Geographic Soc., San Francisco Bay-Delta Science Consortium and CALFED Science Program, Calif. Coastal Conservancy and the Rose Foundation. Additional funding and support was provided by the Stellwagen Bank National Marine Sanctuary

Diagnostic Delay Is Associated with Complicated Disease and Growth Impairment in Paediatric Crohn\u27s Disease

Background: Paediatric data on the association between diagnostic delay and inflammatory bowel disease [IBD] complications are lacking. We aimed to determine the effect of diagnostic delay on stricturing/fistulising complications, surgery, and growth impairment in a large paediatric cohort, and to identify predictors of diagnostic delay. Methods: We conducted a national, prospective, multicentre IBD inception cohort study including 1399 children. Diagnostic delay was defined as time from symptom onset to diagnosis \u3e75th percentile. Multivariable proportional hazards [PH] regression was used to examine the association between diagnostic delay and stricturing/fistulising complications and surgery, and multivariable linear regression to examine the association between diagnostic delay and growth. Predictors of diagnostic delay were identified using Cox PH regression. Results: Overall (64% Crohn\u27s disease [CD]; 36% ulcerative colitis/IBD unclassified [UC/IBD-U]; 57% male]), median time to diagnosis was 4.2 (interquartile range [IQR] 2.0-9.2) months. For the overall cohort, diagnostic delay was \u3e9.2 months; in CD, \u3e10.8 months and in UC/IBD-U, \u3e6.6 months. In CD, diagnostic delay was associated with a 2.5-fold higher rate of strictures/internal fistulae (hazard ratio [HR] 2.53, 95% confidence interval [CI] 1.41-4.56). Every additional month of diagnostic delay was associated with a decrease in height-for-age z-score of 0.013 standard deviations [95% CI 0.005-0.021]. Associations persisted after adjusting for disease location and therapy. No independent association was observed between diagnostic delay and surgery in CD or UC/IBD-U. Diagnostic delay was more common in CD, particularly small bowel CD. Abdominal pain, including isolated abdominal pain in CD, was associated with diagnostic delay. Conclusions: Diagnostic delay represents a risk factor for stricturing/internal fistulising complications and growth impairment in paediatric CD

Connexin 43 mediated gap junctional communication enhances breast tumor cell diapedesis in culture

INTRODUCTION: Metastasis involves the emigration of tumor cells through the vascular endothelium, a process also known as diapedesis. The molecular mechanisms regulating tumor cell diapedesis are poorly understood, but may involve heterocellular gap junctional intercellular communication (GJIC) between tumor cells and endothelial cells. METHOD: To test this hypothesis we expressed connexin 43 (Cx43) in GJIC-deficient mammary epithelial tumor cells (HBL100) and examined their ability to form gap junctions, establish heterocellular GJIC and migrate through monolayers of human microvascular endothelial cells (HMVEC) grown on matrigel-coated coverslips. RESULTS: HBL100 cells expressing Cx43 formed functional heterocellular gap junctions with HMVEC monolayers within 30 minutes. In addition, immunocytochemistry revealed Cx43 localized to contact sites between Cx43 expressing tumor cells and endothelial cells. Quantitative analysis of diapedesis revealed a two-fold increase in diapedesis of Cx43 expressing cells compared to empty vector control cells. The expression of a functionally inactive Cx43 chimeric protein in HBL100 cells failed to increase migration efficiency, suggesting that the observed up-regulation of diapedesis in Cx43 expressing cells required heterocellular GJIC. This finding is further supported by the observation that blocking homocellular and heterocellular GJIC with carbenoxolone in co-cultures also reduced diapedesis of Cx43 expressing HBL100 tumor cells. CONCLUSION: Collectively, our results suggest that heterocellular GJIC between breast tumor cells and endothelial cells may be an important regulatory step during metastasis