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Abstract The political boundaries used to territorialize ocean spaces are often negotiated as largely social relations, with little attention to material aspects. Material aspects of ocean spaces include physical forces, interacting life, and constant transformation. In this paper, we use Steinberg and Peters' (2015) "wet ontology" and concepts of the hydrosphere, liquidity, dynamism, and emergence to reflect on how the Sargasso Sea was located in geographic space through analysis of scientific data that revealed its complex materiality. Drawing from policy documents, white papers, presentations, and 14 semi-structured interviews with scientists, government officials, and NGO representatives, we then trace how the Sargasso Sea Alliance produced the linear boundaries that define the Sargasso Sea as an Ecologically and Biologically Significant Marine Area and, later, as an area for international collaboration on its conservation. Although the data used to locate the Sargasso Sea demonstrated its mobility and complexity, policymaking processes calling for legible boundaries produced a simplified and fixed Sargasso Sea that obscures its "wet" materiality. This 'fixed' Sargasso Sea was created, in part, to test the potential of existing high seas governing bodies in the lead-up to current negotiations for an international legally-binding instrument for high seas governance; this case thus demonstrates how the social relations that construct existing understandings of territory in oceans may continue to dictate policy options, even as new, more dynamic management techniques are developed. We conclude with a discussion of emerging governance possibilities that may better address and account for the entangled material and social realities of oceans. [ABSTRACT FROM AUTHOR]

The apparent prevalence of rare species (rarity) in the deep sea is a concern for environmental management and conservation of biodiversity. Rare species are often considered at risk of extinction and, in terrestrial and shallow water environments, have been shown to play key roles within an ecosystem. In the deep-sea environment, current research focuses primarily on abundant species and deep-sea stakeholders are questioning the importance of rare species in ecosystem functioning. This study asks whether deep-sea stakeholders (primarily scientists) view rare-species research as a priority in guiding environmental management. Delphi methodology (i.e., an iterative survey approach) was used to understand views about whether or not ‘deep-sea scientists should allocate more resources to research on rare species in the deep sea, even if this means less resources might be available for abundant-species research.’ Results suggest little consensus regarding the prioritization of resources for rare-species research. From Survey 1 to Survey 3, the average participant response shifted toward a view that rare-species research is not a priority if it comes at a cost to research on abundant species. Participants pointed to the need for a balanced approach and highlighted knowledge gaps about even the most fundamental questions, including whether rare species are truly ‘rare’ or simply under-sampled. Participants emphasized the lack of basic biological knowledge for rare and abundant species, particularly abundant meio- and microscopic species, as well as uncertainty in the roles rare and abundant species play in ecosystem processes. Approaches that jointly consider the role of rare and abundant species in ecosystem functioning (e.g., biological trait analysis) may help to clarify the extent to which rare species need to be incorporated into deep-sea environment management in order to maintain ecosystem functioning. [ABSTRACT FROM AUTHOR]

• First analysis of HAB species diversity for the Texas coast based on the HTS-metabarcoding. • Identification of 31 HAB OTUs with the 18S rDNA V4 marker; 29 OTUs with the V8-V9 marker. • A total of 36 HAB species were identified, including 5 HAB species recognized for the first time in the GoM. • Phylogenetic analysis is recommended over BLAST for species identification. Environmental-DNA (eDNA) for metabarcoding is a rapid and effective means to investigate microplankton community composition and species diversity. The objective of this study was to examine the genetic diversity of the phytoplankton community in the Gulf of Mexico, with particular emphasis on harmful algal bloom species. Samples were collected at stations along the coast of Texas in September-October 2017 that were inundated by low salinity waters in the aftermath of Hurricane Harvey. Metabarcodes were generated from the eDNA targeting both the V4 and V8-V9 regions of the 18S rDNA gene. Evaluation of the metabarcodes revealed an unexpectedly high number of harmful algal species during this short period, including five that had not been documented in this region previously. A total of 36 harmful algal species could be differentiated based on V4 and V8-V9 metabarcode markers. Using a phylogenetic approach, the taxonomic resolution of each marker differed and not all species could be differentiated using solely one marker. The V4 region resolved species within some genera (e.g., Heterocapsa), while the V8-V9 marker was necessary to resolve species within other genera (e.g., Chattonella). In other cases, species differentiation within a genus required a combination of both markers (e.g., Prorocentrum, Karenia), or another marker will be needed to resolve all species (e.g., Alexandrium, Dinophysis). We conclude that no single marker can delineate all species, so it is recommended HAB monitoring programs use more than one marker. Overall, the observed diversity of HAB species along the Texas coast using metabarcoding exceeded reports from other parts of the world. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To systematically review cognitive behavioral interventions for people with advanced cancer. Methods: A literature search was conducted using Medline©, CINAHL©, and Psych-info©. Inclusion criteria: studies were included in the review if they met the following criteria: (1) the design was a randomized clinical trial, (2) the study tested a cognitive behavioral therapy, including psycho-educational, alternative and complementary therapies (i.e. acupuncture, relaxation), expressive, support and skill building interventions, (3) participants were adults (18 years of age or older) with advanced cancer and the (4) outcomes were directly related to the patient with advanced cancer. Results: 11 studies met the inclusion criteria. Of the studies in the review: treatment effects were not statistically significant in most studies, methods were not consistently described, and samples had limited racial/ethnic diversity. Conclusion: The interpretation of the effectiveness of the CBIs was limited by major challenges to the internal validity of the studies included in the review. The lack of data about the efficacy of CBIs to support people with advanced cancer is a gap in the current knowledge base. Practice implications: Given the needs of people living with advanced cancer well-designed studies are needed to test interventions that will improve outcomes for people living with advanced cancer. [Copyright &y& Elsevier]

Abstract: Karenia is a genus containing at least 12 species of marine unarmored dinoflagellates. Species of the genus can be found throughout the world in both oceanic and coastal waters. They are usually sparse in abundance, but occasionally form large blooms in coastal waters. Most Karenia species produce a variety of toxins that can kill fish and other marine organisms when they bloom. In addition to toxicity, some Karenia blooms cause animal mortalities through the generation of anoxia. At least one species, Karenia brevis, produces brevetoxin that not only kills fish, marine mammals, and other animals, but also causes neurotoxic shellfish poisoning and respiratory distress in humans. The lipid soluble brevetoxin can biomagnify up the food chain through fish to top carnivores like dolphins, killing them. Karenia dinoflagellates grow slowly so physical concentrating mechanisms are probably important for the development of blooms. The blooms are highly sporadic in both time and space, although most tend to occur in summer or fall months in frontal regions. At the present time, our understanding of the causes of the blooms and ability to predict them is poor. Given the recent discovery of new species, it is likely that more Karenia species and toxins will be discovered in the future. [Copyright &y& Elsevier]

Abstract: Karenia brevis (formerly Gymnodinium breve) is a toxic marine dinoflagellate generally restricted to the Gulf of Mexico and is the main causative organism in fish kills, shellfish intoxications and respiratory distress in humans following bloom events. K. mikimotoi is a morphologically similar co-occurring species which is toxic in other parts of the world oceans, but has not been recognized as a major contributor in toxicity of blooms within the Gulf of Mexico. Recently there has been increasing evidence of the simultaneous production of a variety of bioactive compounds in addition to potent neurotoxins (brevetoxin) in Karenia brevis isolates. These compounds are potentially ichthyotoxic and have been shown to cause hemolysis in several bioassays [Eshbach, E., Scharsack, J., John, U., Medlin, L., 2001. Improved erythrocyte lysis assay in microtitre plates for the sensitive detection and efficient measurement of haemolytic compounds from ichthyotoxic algae. J. Appl. Toxicol. 21, 513–519; Kirkpatrick, B., Fleming, L.E., Squicciarini, D., Backer, L.C., Clark, R., Abraham, W., Benson, J., Cheng, Y.S., Johnson, D., Pierce, R., Zaias, J., Bossart, G.D., Baden, D.G., 2004. Literature review of Florida red tide: implications for human health effects. Harmful Algae 3, 99–115]. Presence of hemolytic compounds may therefore add to the overall toxicity levels of bloom events. Current monitoring methods include assays which are highly sensitive in brevetoxin detection and yet may not target other harmful compounds. By adapting protocols developed by Eshbach et al. [Eshbach, E., Scharsack, J., John, U., Medlin, L., 2001. Improved erythrocyte lysis assay in microtitre plates for the sensitive detection and efficient measurement of haemolytic compounds from ichthyotoxic algae. J. Appl. Toxicol. 21, 513–519], Red drum (Sciaenops ocellatus) erythrocytes were used to create a modified bioassay to detect hemolytic activity of crude algal extracts. Red drum was selected because it is endemic to coastal areas throughout the Gulf of Mexico and is sensitive to Karenia blooms, and thus makes this species a valid ecological target. Preliminary data has shown this method is sensitive for use in assessing hemolysis induced by laboratory cultures down to levels of 1×103 cellsmL−1. Results showed an unexpectedly high level of hemolytic activity among K. mikimotoi clones, with one Texas strain inducing significantly higher hemolysis compared to Florida K. brevis isolates. Using this approach, future research efforts will examine the difference in production of hemolytic compounds among various Karenia clones. [Copyright &y& Elsevier]

This study examined the relationship between patient and partner ratings of self-efficacy for symptom control and quality of life (QOL) among 40 African American prostate cancer survivors and their intimate partners. Data analyses revealed that cancer survivors who had rated their self-efficacy for symptom control higher reported better QOL related to urinary, bowel, and hormonal symptoms and better general health QOL (i.e., better physical functioning and better mental health). Data analyses also revealed that partners who rated their self-efficacy for helping the patient manage symptoms as higher reported better QOL (i.e., less negative mood and less caregiver strain). Finally, exploratory analyses indicated that higher self-efficacy in patients was associated with less anxiety and caregiver strain in partners, and higher self-efficacy in partners was associated with better adjustment to bowel and hormonal symptoms and better mental health in patients. The clinical implications of these findings are discussed and future directions for research on self-efficacy in African American prostate cancer survivors are identified. [Copyright &y& Elsevier]

This review highlights recent research findings on the relationship between persistent pain and depression and discusses the implications of these findings for future research in persons who suffer from both pain and depression. First, we briefly discuss advances in theories of pain that underscore the important role that depression can play in the chronic pain experience. Second, we discuss depression in persons suffering from chronic pain from a biopsychosocial perspective that takes into account both biological and psychosocial mechanisms linking pain and depression. Third, we address biomedical, psychosocial, and combined medical–psychosocial approaches to treatment in persons with persistent pain and depression. We conclude by highlighting future directions for research related to screening and diagnosis of depression in persons having persistent pain, treatment of comorbid pain and depression, and individual and subgroup differences in the experience of persistent pain and depression. [Copyright &y& Elsevier]

Target-based governance holds the promise of accountability by measuring progress towards objectives set within global environmental agreements. This approach has been widely adopted at multiple scales of governance in conservation and sustainability sectors including by the Convention on Biological Diversity (CBD). Yet the implications of governing through targets have not been fully scrutinized for the ways that targets and their associated indicators shape the work by global conventions, including the activities pursued by state and non-state actors. We systematically reviewed, coded and assessed the peer-reviewed scientific literature produced in relation to the CBD Aichi Biodiversity Targets (ABTs) to demonstrate the types of scientific action that the Aichi targets have motivated, and assess how this work serves to reinforce particular visions of what conservation is and how it should be done. We find widespread support for target-based governance in the scientific literature. We also find uneven attention across the targets (e.g. mostly the protected areas target), to particular elements within specific targets (e.g. the area-based element of the protected areas target), measured by particular forms of knowledge (i.e. primarily biophysical data aggregated at a global scale). We argue that the uneven scientific action associated with the ABTs arises from the interplay among target elements that can be readily measured (e.g. by existing single-metric indicators) and long-standing institutional commitments (e.g. to protected areas expansion). With the Post-2020 Global Biodiversity Framework on the immediate horizon, there is a timely opportunity to reflect on the role of targets within the CBD and beyond. • Targets have become a key approach for governing biodiversity including within the Convention on Biological Diversity (CBD). • We systematically assessed the types of scientific action produced in relation to the CBD's Aichi Biodiversity Targets (ABTs). • Most scientific research in relation to the ABTs focusses on one aspect (area) of one target (the protected areas target). • Critical reflection on how targets regimes serve to winnow and structure the realm of actionable knowledge is needed. [ABSTRACT FROM AUTHOR]

Discusses the annual variability of phytoplankton and bacteria in the subtropical North Pacific Ocean. Analysis of flow cytometry; Consequence of phytoacclimation; Presence of seasonal pattern in total phytoplankton biomass; Effects of extended El Nino-Southern Oscillation (ENSO).

• Diarrhetic shellfish toxin in non-commercial mussels exceeded FDA guidance level. • DTX-2 dominated the toxin profile, DTX-1 and OA also detected in mussel tissue. • Sixty-one percent of samples had detectable levels of diarrhetic shellfish toxin. • Dinophysis concentration peaked in summer months (May-July). • Dinophysis concentration alone is a weak predictor of toxin level in shellfish. Diarrhetic shellfish toxins (DSTs) are produced by the marine dinoflagellate, Dinophysis, as well as select species of benthic Prorocentrum. The DSTs can bioaccumulate in shellfish and cause gastrointestinal illness when humans consume high levels of this toxin. Although not routinely monitored throughout the U.S., recent studies in Washington, Texas, and New York suggest DSTs may be widespread throughout U.S. coastal waters. This study describes a four-year time series (2013–2016) of Dinophysis concentration and DST level in California mussels (Mytilus californianus) from Santa Cruz Municipal Wharf (SCMW) in Monterey Bay, California. Results show a maximum Dinophysis concentration of 9404 cells/L during this study and suggest Dinophysis persists as a member of the background phytoplankton community throughout the year. In California mussels, DSTs were found at persistent low levels throughout the course of this study, and exceeded the FDA guidance level of 160 ng/g 19 out of 192 weeks sampled. Concentrations of Dinophysis alone are a positive but weak predictor of DST level in California mussels, and basic environmental variables (temperature, salinity, and nutrients) do not sufficiently explain variation in Dinophysis concentration at SCMW. This study demonstrates that Dinophysis in Monterey Bay are producing DSTs that accumulate in local shellfish throughout the year, occasionally reaching levels of concern. [ABSTRACT FROM AUTHOR]

Harmful algal blooms caused by Karenia brevis result in large fish kills, human respiratory irritation, and shellfishing closures in affected areas. Most previous work on bloom formation in the Gulf of Mexico has focused on the west coast of Florida. To investigate the origin of bloom-forming cells along the coast of Texas, potential distributions of cells during two bloom years (2009, 2011) and one non-bloom year (2010) were examined using a spatially explicit, individual-based model of K. brevis . The model incorporates a previously developed model of dinoflagellate vertical migration and utilizes observed data (field samples of cell concentrations, photosynthetically active radiation) and modeled environmental output (salinity, temperature, current velocities) from a hydrodynamic model. Running the model in reverse showed that cells near the coast of Texas during early fall originate from the southern Gulf of Mexico in bloom years and from the northern Gulf of Mexico in the non-bloom year for the three years studied. Identification of a southern origin for bloom-forming cells provides a target area for increased sampling in order to provide early warning of potentially harmful algal blooms of K. brevis . [ABSTRACT FROM AUTHOR]

Abstract: Nucleic acid sequence-based amplification (NASBA) is an isothermal method used to amplify RNA and has been used for clinical, environmental, and food testing applications. Quantification of RNA by real-time NASBA occurs by comparing time to positive (TTP) fluorescence values, similar to threshold cycle (Ct) values in PCR, of unknown samples to a standard curve of known RNA titers. Incorporation of an internal control RNA molecule (IC-RNA) has been used to increase precision and accuracy of real-time NASBA and also serves as an indicator of NASBA inhibition. A real-time IC-NASBA assay was developed targeting the ribulose-1,5-bisphosphate carboxylase-oxygenase (RuBisCO) large-subunit gene (rbcL) of the harmful algal bloom (HAB) causing dinoflagellate Karenia mikimotoi. This assay is sensitive to one K. mikimotoi cell and 1×103 copies of in vitro transcript with a high degree of specificity against closely related organisms. Enumeration of K. mikimotoi from environmental samples by IC-NASBA was not significantly different from microscopic cell counts (P =0.156, α =0.05) performed by the Fish and Wildlife Research Institute (FWRI, a division of the Fish and Wildlife Conservation Commission, St. Petersburg, FL), the agency responsible for monitoring red tide status throughout the state. In addition, the IC-NASBA enumeration had a good linear relationship (r 2 =0.887) with FWRI microscopic cell counts. IC-NASBA is an alternative method for the rapid and reliable detection and quantification of K. mikimotoi from marine waters. [Copyright &y& Elsevier]

1. Name areas for improvement in end-of-life care for transgender elders. 2. Advocate for strategies to meet the unique needs of transgender elders at end of life. The WHO estimates that 20 million adults across the globe need palliative and end-of-life (EOL) care, including a growing cohort of transgender elders. Little data exist on the intersectionality of gender identity, aging, and needs for care at end of life. What quality care looks like can best be described by transgender elders and key allies. A 2-day think tank was convened by an interprofessional planning committee that invited participation from transgender elders, community advocates, scholars in EOL care, policy-makers, and palliative care providers via a video conferencing platform to generate recommendations for EOL care for transgender elders. Subsequently a qualitative analysis of the written record of think tank discussions was conducted in order to identify themes. Four major themes for recommendations were identified: (1) understanding the complexities of transgender life experiences, (2) addressing end-of-life healthcare and advance care planning needs for transgender elders, (3) engaging with and serving the community of transgender elders, and (4) facilitating inclusion and fighting discrimination with education and policy. These themes highlight the complexity of planning for the EOL experiences of transgender elders. It is essential for future research policy and education initiatives to address the needs of transgender elders to ensure inclusive and equitable provision of EOL care by healthcare providers for this population. [ABSTRACT FROM AUTHOR]

• New isolates of T. amphioxeia and D. ovum established from the Gulf of Mexico. • Dinophysis ovum and Dinophysis acuminata growth was optimal at 18 – 24 °C and salinities 22 – 26. • D. acuminata and D. ovum have unique toxin profiles for North American region. • Dinophysis blooms in the Gulf of Mexico are likely initiated by temperature increase in spring. Mixotrophic Dinophysis species threaten human health and coastal economies through the production of toxins which cause diarrhetic shellfish poisoning (DSP) in humans. Novel blooms of Dinophysis acuminata and Dinophysis ovum have occurred in North American waters in recent decades, resulting in the closure of shellfish harvesting. Understanding the ecology of Dinophysis species and their prey is essential to predicting and mitigating the impact of blooms of these dinoflagellates. The growth response of two new isolates of Dinophysis species, one isolate of Mesodinium rubrum , and two strains of Teleaulax amphioxeia were evaluated at a range of temperature, salinity, and irradiance treatments to identify possible environmental drivers of Dinophysis blooms in the Gulf of Mexico. Results showed optimal growth of T. amphioxeia and M. rubrum at 24 °C, salinity 30 – 34, and irradiances between 300 and 400 µmol quanta m −2 s −1. Optimal Dinophysis growth was observed at salinity 22 and temperatures between 18 and 24 °C. Mesodinium and both Dinophysis responded differently to experimental treatments, which may be due to the suitability of prey and different handling of kleptochloroplasts. Dinophysis bloom onset may be initiated by warming surface waters between winter and spring in the Gulf of Mexico. Toxin profiles for these two North American isolates were distinct; Dinophysis acuminata produced okadaic acid, dinophysistoxin-1, and pectenotoxin-2 while D. ovum produced only okadaic acid. Toxin per cell for D. ovum was two orders of magnitude greater than D. acuminata. Phylogenies based on the cox1 and cob genes did not distinguish these two Dinophysis species within the D. acuminata complex. [ABSTRACT FROM AUTHOR]

• Interaction between upwelling and river discharge influenced phytoplankton community. • Stronger upwelling in 2013 led to a diatom-dominated phytoplankton community. • Coastal upwelling recognized as a strong temporal forcing factor in Gulf of Mexico. • Spatial variations in assemblages were determined by upwelling and river discharge. • Dinoflagellates were more prevalent than previously documented in the region. The regional circulation in the northwestern Gulf of Mexico during late spring-summer is modulated by upwelling-favorable winds that can cause coastal upwelling in the western region and by freshwater inputs from the Mississippi-Atchafalaya Rivers. Spatial variability and temporal dynamics of phytoplankton community composition were examined during two upwelling-favorable periods using data obtained with an Imaging FlowCytobot (IFCB) from two cruises on the Texas-Louisiana shelf in June 2013 and 2014 and from the Texas Observatory for Algal Succession Time series (TOAST) at Port Aransas (Texas). Phytoplankton spatial distributions were determined by the influence of upwelling and river discharged waters. In the 2013 cruise, upwelling was detected in a large portion of the western region and the phytoplankton assemblages were dominated by diatoms, mostly chain-forming taxa. As revealed by the TOAST time series, the upwelling onset caused a dramatic increase in diatom carbon biomass. In the areas not affected by upwelling, variation in the river plume distribution that resulted from the circulation and the different discharge magnitudes for each year influenced the spatial distributions of the phytoplankton community composition. Dinoflagellates and other flagellated taxa were notably dominant during the 2013 cruise, whereas both diatoms and flagellated groups dominated the assemblages during the 2014 cruise. High stratification promoted by freshwater input, notably higher during 2013 than 2014, likely favored the dominance of flagellated groups in 2013. This study provides evidence of the influence of coastal upwelling in the phytoplankton community of the northwestern Gulf of Mexico and contributes to the knowledge of the drivers of community composition in this high-productivity area. [ABSTRACT FROM AUTHOR]

One of the most widely studied organisms responsible for Harmful Algal Blooms (HABs) is the marine dinoflagellate Karenia brevis . This organism produces neurotoxic compounds known as brevetoxins. A related dinoflagellate, Karenia papilionacea , has been reported to occasionally co-bloom with K. brevis but has received little attention as a possible toxin producing species. Therefore, our aim was to investigate the toxin profile for K. papilionacea . A toxic fraction was identified using a cell based cytotoxicity assay and the toxin was isolated and identified as the ladder frame polyether brevetoxin-2 (PbTx-2) using mass spectrometry (MS) and nuclear magnetic resonance (NMR). Toxin production in K. papilionacea increased in response to hypoosmotic stress, as previously observed in K. brevis . [ABSTRACT FROM AUTHOR]

Objective: To investigate whether gonadotropin-releasing hormone (GnRH) and GnRH receptor (GnRHR) are expressed at tubal ectopic pregnancy sites, and to study the potential role of GnRH signaling in regulating immortalized human trophoblast cell viability.Design: Immunohistochemical and experimental studies.Setting: Academic research laboratory.Patient(s): Fallopian tube implantation sites (n = 25) were collected from women with ectopic pregnancy. First-trimester human placenta biopsies (n = 5) were obtained from elective terminations of pregnancy.Intervention(s): None.Main Outcome Measure(s): GnRH and GnRHR expression was examined by means of immunohistochemistry and histoscoring. Trophoblastic BeWo choriocarcinoma and immortalized extravillous trophoblast (HTR-8/SVneo) cell viability was examined by means of cell counting after incubation with GnRH and/or GnRH antagonist (Antide).Result(s): GnRH and GnRHR immunoreactivity was detected in cytotrophoblast, syncytiotrophoblast, and extravillous trophoblast in all women with tubal pregnancy. GnRH immunoreactivity was higher and GnRHR immunoreactivity lower in syncytiotrophoblast compared with cytotrophoblast. GnRH and GnRHR immunoreactivity was detected in adjacent fallopian tube epithelium. Whereas neither GnRH nor Antide altered HTR-8/SVneo cell viability, treatment with GnRH significantly increased the overall cell viability of BeWo cells at 48 and 72 hours, and these effects were abolished by pretreatment with Antide.Conclusion(s): GnRH and GnRHR are expressed in trophoblast cell populations and fallopian tube epithelium at tubal ectopic pregnancy sites. GnRH increases BeWo cell viability, an effect mediated by the GnRHR. Further work is required to investigate the potential role of GnRH signaling in ectopic pregnancy. [ABSTRACT FROM AUTHOR]

Abstract: Karenia brevis is the major harmful bloom-forming dinoflagellate in the Gulf of Mexico yet little is known about the intraspecific genetic diversity of this species. Here we describe nine new microsatellite markers and, combined with nine previously described microsatellites, use them to genotype 40 cultured isolates of K. brevis. Genetic diversity identified from cultured isolates was compared with the genetic diversity identified from two field samples to assess how well the current cultures represent the field population. Thirty-nine unique haplotypes were identified from 40 cultured isolates of K. brevis using 18 microsatellite markers. Genetic diversity was similar between cultured isolates and the two field samples. The success of 18 microsatellite markers to distinguish individual isolates supports the use of microsatellites as a genetic tool for diagnostic identification of cultured isolates of K. brevis. [Copyright &y& Elsevier]

Abstract: The dinoflagellate Karenia brevis is responsible for nearly annual red tides in the Gulf of Mexico that cause extensive marine mortalities and human illness due to the production of brevetoxins. Although the mechanisms regulating its bloom dynamics and toxicity have received considerable attention, investigation into these processes at the cellular and molecular level has only begun in earnest during the past decade. This review provides an overview of the recent advances in our understanding of the cellular and molecular biology on K. brevis. Several molecular resources developed for K. brevis, including cDNA and genomic DNA libraries, DNA microarrays, metagenomic libraries, and probes for population genetics, have revolutionized our ability to investigate fundamental questions about K. brevis biology. Two cellular processes have received particular attention, the vegetative cell cycle and vertical migration behavior, which are of key importance due to their roles in the development of both surface populations that constitute blooms and subsurface cell aggregations that may serve to initiate them. High throughput sequencing of cDNA libraries has provided the first glimpse of the gene repertoire in K. brevis, with approximately 12,000 unique genes identified to date. Phylogenomic analysis of these genes has revealed a high rate of horizontal gene transfer in K. brevis, which has resulted in a chimeric chloroplast through the selective retention of genes of red, green, and haptophyte origin, whose adaptive significance is not yet clear. Gene expression studies using DNA microarrays have demonstrated a prevalence of post-transcriptional gene regulation in K. brevis and led to the discovery of an unusual spliced leader trans-splicing mechanism. Among the trans-spliced gene transcripts are type I polyketide synthases (PKSs), implicated in brevetoxin biosynthesis, which are unique among type I PKSs in that each transcript encodes an individual catalytic domain, suggesting a novel gene structure in this dinoflagellate. Clone libraries of 16S ribosomal DNA sequences developed from bloom waters have unveiled the temporal and spatial complexity of the microbial soup that coexists with K. brevis and its active involvement in both bloom growth and termination processes. Finally, the development and application of population genetic markers has revealed a surprisingly high genetic diversity in K. brevis blooms, long assumed to consist of essentially clonal populations. With these foundations in place, our understanding of K. brevis bloom dynamics is likely to grow exponentially in the next few years. [Copyright &y& Elsevier]

• Geographically distant Pseudo-nitzschia multistriata isolates are sexually compatible. • Microsatellites analyses show that distant isolates belong to different populations. • Three new alleles for the sex locus are found in P. multistriata Atlantic strains. • The gene MRP3 is expressed on the new allele A2, specific for mating type +. The cosmopolitan, species-rich diatom genus Pseudo-nitzschia represents a good system for the study of speciation, evolution and diversity. Understanding elements linked to population dynamics and life cycle regulation for these species is of particular importance in view of their ability to produce the toxin domoic acid and cause harmful blooms. Pseudo-nitzschia multistriata , one of the toxic species that represents a model for the study of life cycle related questions, is the only diatom for which a sex determination mechanism has been described. Populations in the Gulf of Naples (Mediterranean Sea), can share four different allelic variants (A, M, B, N) of the mating type determination region, and one of them (A) is responsible for the determination of the mating type + (MT+), defined by the MT+ restricted expression of the gene MRP3. Here, we analysed the sex determination genomic region in three new strains isolated from the Gulf of Mexico and compared it to the alleles previously described in the Mediterranean strains. We first show that these geographically distant strains of P. multistriata belong to different populations but can interbreed. Next, we show that the two populations share an overall similar structure of the genomic locus although differences can be seen in the polymorphic regions upstream of MRP3. In strain P4-C1, we amplified and sequenced an allele (M) identical to one of those previously characterized in the Mediterranean strains. In the other two strains, P4-C2 and P4-C5, we identified three new alleles, which we named A2, B2 and N2. P4-C2 and P4-C5 are heterozygous and share the common allele A2 linked to the monoallelic expression of the MT+ specific sex determining gene MRP3. Our results expand information on the global distribution of P. multistriata and on the level of conservation of the sex determination region in different populations. The definition of the extent of intra- and inter-specific conservation of this region would be a relevant addition to our understanding of Pseudo-nitzschia diversity and evolution. [ABSTRACT FROM AUTHOR]