Changes in toxin content, biomass and pigments of the dinoflagellate Alexandrium minutum during nitrogen refeeding and growth into nitrogen or phosphorus stress

Two strains oi the paralytic shellfish toxin (PST) producing dinoflagellate Alexandrium minutum Halim (highly toxic ALl V and weakly toxic AL2V) were grown in batch culture with either nitrate or phosphate as the limiting nutrient. In comparison with cells of the strain AL1V, cells of AL2V grew at a similar C-specific Tale, had a higher C/N ratio, and lower ratios of chl a/chl C2and chl a/peridinin. Neither chlorophylls flor carotenoids could be used to estimate C-biomass, N-biomass or toxin content for this organismo The toxin profile for both strains was dominated (up to 95 %) by the gonyautoxin GTX4, with smaller proportions of GTX1, GTX2 and GTX3. The Tale of toxin synthesis for both strains was greatest 1 to 2 d after the N-refeeding of N-deprived cells, with the net Tale of toxin syn- .thesis exceeding that of C-biomass and cell division by a factor of up to 4. Toxin synthesis was not enhanced by short-term P-stress. N-stress alone led to a decrease in toxin cell-I, but P-stress followed by N-stress did not result in such a decline, implicating phosphorus in the regulation of toxin metabolism. Although arginine is a majar precursor for PST synthesis, taurine, glycine, glutamine, and cell N showed similar relations to that observed for arginine with respect to toxin contento Furthermore, the mole ratio of arginine/toxin could vary by a factor of up to 5 between AL1V and AL2V at peak values of toxin cell-1, and by more than 5 within a strain when growing under different conditions. These observations suggest that the relationship between free arginine content and toxin content is complex. No explanation for the higher toxin content of AL1V is apparent, except that AL1V has a higher N-content per cell and this may be conducive to a higher Tale of synthesis of the N-rich toxins.Publicado

Evidence for production of paralytic shellfish toxins by bacteria associated with Alexandrium spp. (Dinophyta) in culture

A substantial proportion of bacteria from five Alexandrium cultures originally isolated from various countries produced sodium channel blocking (SCB) toxins, as ascertained by mouse neuroblastoma assay. The quantities of SCB toxins produced by bacteria and dinoflagellates were noted, and the limitations in comparing the toxicities of these two organisms are discussed. The chemical nature of the SCB toxins in selected bacterial isolates was determined as paralytic shellfish toxins by pre- and postcolumn high-performance liquid chromatography, capillary electrophoresis-mass spectrometry, and enzyme immunoassay.Versión del editor3,829

Future HAB science: Directions and challenges in a changing climate

There is increasing concern that accelerating environmental change attributed to human-induced warming of the planet may substantially alter the patterns, distribution and intensity of Harmful Algal Blooms (HABs). Changes in temperature, ocean acidification, precipitation, nutrient stress or availability, and the physical structure of the water column all influence the productivity, composition, and global range of phytoplankton assemblages, but large uncertainty remains about how integration of these climate drivers might shape future HABs. Presented here are the collective deliberations from a symposium on HABs and climate change where the research challenges to understanding potential linkages between HABs and climate were considered, along with new research directions to better define these linkages. In addition to the likely effects of physical (temperature, salinity, stratification, light, changing storm intensity), chemical (nutrients, ocean acidification), and biological (grazer) drivers on microalgae (senso lato), symposium participants explored more broadly the subjects of cyanobacterial HABs, benthic HABs, HAB effects on fisheries, HAB modelling challenges, and the contributions that molecular approaches can bring to HAB studies. There was consensus that alongside traditional research, HAB scientists must set new courses of research and practices to deliver the conceptual and quantitative advances required to forecast future HAB trends. These different practices encompass laboratory and field studies, long-term observational programs, retrospectives, as well as the study of socioeconomic drivers and linkages with aquaculture and fisheries. In anticipation of growing HAB problems, research on potential mitigation strategies should be a priority. It is recommended that a substantial portion of HAB research among laboratories be directed collectively at a small sub-set of HAB species and questions in order to fast-track advances in our understanding. Climate-driven changes in coastal oceanographic and ecological systems are becoming substantial, in some cases exacerbated by localized human activities. That, combined with the slow pace of decreasing global carbon emissions, signals the urgency for HAB scientists to accelerate efforts across disciplines to provide society with the necessary insights regarding future HAB trends

Use of SMS texts for facilitating access to online alcohol interventions: a feasibility study

A41 Use of SMS texts for facilitating access to online alcohol interventions: a feasibility study In: Addiction Science & Clinical Practice 2017, 12(Suppl 1): A4

TRY plant trait database – enhanced coverage and open access

Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits—almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

Narrowband Searches for Continuous and Long-duration Transient Gravitational Waves from Known Pulsars in the LIGO-Virgo Third Observing Run

Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully coherent search for such signals from eighteen pulsars in data from LIGO and Virgo's third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow both the frequency and the time derivative of the frequency of the gravitational waves to vary in a small range around those inferred from electromagnetic observations. We find no evidence for continuous gravitational waves, and set upper limits on the strain amplitude for each target. These limits are more constraining for seven of the targets than the spin-down limit defined by ascribing all rotational energy loss to gravitational radiation. In an additional search, we look in O3 data for long-duration (hours-months) transient gravitational waves in the aftermath of pulsar glitches for six targets with a total of nine glitches. We report two marginal outliers from this search, but find no clear evidence for such emission either. The resulting duration-dependent strain upper limits do not surpass indirect energy constraints for any of these targets. © 2022. The Author(s). Published by the American Astronomical Society

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo