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This study reports on a novel strategy for manufacturing thickened gel-like castor oil formulations by dispersing electrospun lignin/ethylcellulose nanostructures. These thickened formulations were rheologically and tribologically evaluated with the aim of being proposed as alternative ecofriendly lubricating greases. Low-sulfonate kraft lignin (LSL) and ethylcellulose (EC) were dissolved in a DMAc:THF mixture at different concentrations (8, 10, and 15 wt.%) and LSL:EC ratios (50:50, 70:30, and 90:10) and subjected to electrospinning. The resulting electrospun nanostructures were morphologically characterized. EC acting as the cospinning polymer improved both LSL spinnability and the oil structuring ability. Solutions with a high lignin content achieved microsized particles connected by fibrils, whereas solutions with a high EC content (50:50 ratio) and LSL/EC total concentration (10 and 15 wt.%) yielded beaded or bead-free nanofibers, due to enhanced extensional viscoelastic properties and nonNewtonian characteristics. The gel-like properties of electrospun nanostructure dispersions in castor oil were strengthened with the nanostructure concentration and the EC:LSL ratio, as a result of the formation of a more interconnected fiber network. The oleodispersions studied exhibited a satisfactory frictional response in a tribological contact, with friction coefficient values that were comparable to those achieved with traditional lithium-lubricating greases, This work was supported by MCIN/AEI/10.13039/501100011033, by “ERDF—A way of making Europe” (grant number: RTI2018-096080-BC21) and by Junta de Andalucía/EPIT2020-UHU (grant numbers: PY20_00751 and UHU202029) by the FEDER European Programme

12 Pág., Lignin-enriched waste products from bioethanol production of agriculture residues were tested as structuring agents in castor oil once functionalized with hexamethylene diisocyanate. Cane bagasse, barley and wheat straw were processed through steam explosion, pre-saccharification and simultaneous saccharification and fermentation (PSSF). Alternatively, cane bagasse was submitted to steam explosion and enzymatic hydrolysis (EH). Several Nuclear Magnetic Resonance techniques were used to characterize both residues and NCO-functionalized counterparts. The β-O-4'/resinol/phenylcoumaran content and hydroxyphenyl/guaiacyl/syringyl distribution depend on biomass source, pretreatment, and enzymatic hydrolysis. Total hydroxyl content (from 1.23 for cane bagasse to 1.85 for wheat straw residues), aromatic/aliphatic hydroxyl ratio (0.78 for cane bagasse and 0.61 and 0.49 for barley and wheat straw residues, respectively) and S/G ratio (ranging from 0.25 to 0.86) influence the NCO-functionalization and oleogel rheological response. Oleogels obtained with barley straw residues exhibited the highest values of the storage modulus; around 2 × 105 Pa and 104 Pa for 25% and 20% contents, respectively. PSSF process showed weaker modification, leading to softer viscoelastic response compared to EH. These oleogels exhibited rheological properties similar to lubricating greases of different NLGI grades. Therefore, we herein show an integrative protocol for the valorization of lignin-enriched residues from bioethanol production as potential thickeners of lubricating greases., This work is part of two coordinated research projects (RTI2018-096080-B-C21 and RTI2018-096080-B-C22) funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”. The financial support is gratefully acknowledged. A.M.B-L. also acknowledges the Ph.D. Research Grant FPU16/03697 from MECD (Spain).

An o-nitrobenzyl-protected precursor was used as a phototrigger for the release of the diamine cadaverine in polyurethane adhesives based on castor oil as a renewable source of polyol and organic diisocyanates. This resulted in formulations with suitably controlled curing by photoactivation. This material shows faster curing when UV light is applied as compared to curing in the absence of irradiation, which was in situ monitored by rheological measurements. In addition, the adhesion performance is superior, reaching lap shear strength values of up to 4600 kPa, which is unprecedented for bio-based adhesives. On one hand, the in-depth chemical characterization with FTIR spectroscopy revealed that the slow release of cadaverine yields a well-balanced urethane/urea composition with direct impact on adhesion properties. The photocured bioadhesive was shown to bond a variety of surfaces, such as polyethylene or even wood. On the other hand, the direct one-time addition of cadaverine yields a material with approximately the same viscoelastic properties, which were achieved almost immediately as a consequence of the favored fast formation of urea bonds in detriment of urethanes, however, lacking adhesion properties., We are grateful for financial support through the project UHU-1252599, financed by the University of Huelva, in the frame of the European Regional Development Fund (ERDF)-Junta de Andalucía 2014−2020 Operational Programme. A.M.B.-L. acknowledges the Spanish Ministerio de Educación, Cultura y Deporte for the award of a doctoral fellowship (FPU16/03697)., Funding for open access charge: Universidad de Huelva / CBUAUniversity of Huelva, in the frame of the European Regional Development Fund (ERDF)-Junta de Andalucía 2014−2020 Operational Programme. Ministerio de Educación, Cultura y Deporte (FPU16/ 03697) Funding for open acess charge: Universidad de Huelva/CBUA

This work explores the electrospinnability of low-sulfonate Kraft lignin (LSL)/polyvinylpyrrolidone (PVP) solutions in N,N-dimethylformamide (DMF) and the ability of the different micro- and nano-architectures generated to structure castor oil. LSL/PVP solutionswere prepared at different concentrations (8–15wt%) and LSL:PVP ratios (90:10–0:100) and physico-chemically and rheologically characterized. The morphology of electrospun nanostructures mainly depends on the rheological properties of the solution. Electrosprayed nanoparticles or micro-sized particles connected by thin filamentswere obtained fromsolutionswith lowLSL/PVP concentrations and/or high LSL:PVP ratios,whereas beaded or bead-free nanofibers were produced by increasing concentration and/or decreasing LSL:PVP ratio, due to enhanced extensional viscoelastic properties and non-Newtonian characteristics. Electrospun LSL/PVP nanofibers are able to form oleogels by simply dispersing them into castor oil at concentrations between 10 and 30 wt%. The rheological properties of the oleogels may be tailored bymodifying the LSL:PVP ratio and nanofibers content. The potential application of these oleogels as bio-based lubricants was also explored in a tribological cell. Satisfactory friction and wear results are achieved when using oleogels structured by nanofibers mats with enhanced gel-like properties as lubricants. Overall, electrospinning of lignin/ PVP solutions can be proposed as a simple and effective method to produce nanofibers for oil structuring, Funding for open access charge: Universidad de Huelva / CBUAThis work is part of a research project (RTI2018-096080-B-C21) sponsored by the MICINN-FEDER I+D+i Spanish Programme

Summary The interplay between the phytohormone abscisic acid (ABA) and the gasotransmitter nitric oxide (NO) regulates seed germination and post-germinative seedling growth. We show that GAP1 (germination in ABA and cPTIO 1) encodes the transcription factor ANAC089 with a critical membrane-bound domain and extranuclear localization. ANAC089 mutants lacking the membrane-tethered domain display insensitivity to ABA, salt, and osmotic and cold stresses, revealing a repressor function. Whole-genome transcriptional profiling and DNA-binding specificity reveals that ANAC089 regulates ABA- and redox-related genes. ANAC089 truncated mutants exhibit higher NO and lower ROS and ABA endogenous levels, alongside an altered thiol and disulfide homeostasis. Consistently, translocation of ANAC089 to the nucleus is directed by changes in cellular redox status after treatments with NO scavengers and redox-related compounds. Our results reveal ANAC089 to be a master regulator modulating redox homeostasis and NO levels, able to repress ABA synthesis and signaling during Arabidopsis seed germination and abiotic stress., Graphical abstract, Highlights • GAP1 encodes transcription factor ANAC089, expressed in seeds and stress • Changes in cellular redox status induce translocation of ANAC089 to the nucleus • ANAC089 binds specifically to genes controlling seed germination and abiotic stress • ANAC089 regulates NO levels and cell redox and represses ABA synthesis and signaling, Albertos et al. report the cleavage of ANAC089 transcription factor from the membrane-anchoring domain in the endoplasmic reticulum, controlled by cell redox alterations. Once in the nucleus, ANAC089 induces redox homeostasis-related genes and represses ABA-responsive genes to increase NO levels and ABA insensitivity during seed germination and abiotic stress.

Lignin is demonstrated as an unprecedented reinforcing material that tailors the rheological and cushioning properties of castor oil-based polyurethane elastomers, expanding their viscoelastic moduli by four orders of magnitude. The tensile strain at break was triplicated in the presence of lignin while the Young modulus and the stress at break were enhanced 17- and 7-fold, respectively. Remarkably, in compression tests, lignin addition increased the stresses at break by more than 88-fold, whereas the strain at failure shifted from 50 to 93%. Dynamic mechanical compression tests indicated outstanding cushioning and resistance performance. Overall, the results demonstrate a performance not reached before for biosourced elastomeric materials, fitting the demands of a wide range of applications.

This work presents a comprehensive study on the influence of processing variables (temperature, agitation speed) and type of diisocyanate crosslinker on the rheological properties of liquid and gel-like polyurethane formulations based on lignin and castor oil. With this aim, a green and facile one-step preparation protocol which avoids the use of any harmful catalyst or solvent was proposed. Different processing temperatures (25, 45, 70 °C), stirring speeds (23, 70, 140 rpm) and kinds of diisocyanates (hexamethylene diisocyanate, and toluene diisocyanate) were selected to process the different bio-sourced polyurethane samples. These processing variables have proven to be crucial to modulate and control the rheological (viscous and viscoelastic) properties, and curing kinetics after processing, due to the different chemical structures achieved that were elucidated by means of Fourier-transform infrared spectroscopy and differential scanning calorimetry. In general, a low processing temperature and low stirring speed favour the achievement of gel-like characteristics and/or the formation of highly viscous polyurethanes, as a consequence of a higher number of total hydrogen-bonded carbonyl groups, urethane/urea ratio and ratio of hydrogen-bonded/non-bonded urethane and urea linkages. Besides, the selected one-step process, in comparison with the reported two-step process, provides polyurethanes with similar rheological characteristics by significantly reducing the isocyanate content. Finally, lignin was demonstrated to act as an effective filler agent increasing the values of the viscoelastic moduli.

The replacement of mineral oils and non-renewable gelling agents is an imperative requirement for the lubricant industry in the near future. In this framework, cellulose pulp and castor oil are proposed as sustainable substitutes for these components. Biological treatment has been explored and evaluated to enhance the dispersing and thickening properties of cellulose pulp in oil media. Streptomyces sp. MDG147 and MDG301 strains were employed to modify agricultural wheat and barley straw residues from which cellulose pulp was obtained afterwards. In addition, an environmentally friendly process for the production of cellulose-pulp-/castor-oil-based polyurethanes was applied, in which neither catalysts nor harmful solvents were used, resulting in chemical oleogels. These oleogels were rheologically and tribologically characterized to evaluate their performance as lubricating greases. The enzymatic activity pattern developed was dependent on the raw material, the strain type, and the temperature, influencing the cellulose pulp&rsquo, s composition, polymerization degree, and crystallinity. These modified characteristics tuned the rheological behavior of the different oleogels, providing a beneficial range of viscoelastic responses and viscosity values that were generally favored by the Streptomyces action. Furthermore, the friction coefficient and dimensions of wear scars measured in a tribological contact were comparable to, or even lower than, those found with commercial and other bio-based lubricating greases that have previously been studied.

The applications of biogenic lubricating greases to machine elements play important roles in the reduction of friction energy and minimizing wear in a tribological contact, as well as the prevention of environmental pollution. The aim of this work was to investigate completely biogenic lubricating greases from a tribological point of view. Model greases were examined using a ball on a disc tribometer at a constant normal force to investigate the friction and wear process according to Fleischer&rsquo, s energetic wear model. Using the energy-based wear model, the friction and wear process could be interpreted as a cause&ndash, effect sequence. Moreover, the influence of the model grease composition on the friction and wear process was analyzed. In addition, rolling bearing tests were performed to investigate the tribological behaviors of some selected biogenic greases during real machine element contact. These tests allowed for the quantification of the friction torque behavior of the full bearing and the evaluation of the wear obtained through lubricant analysis procedures. This experimental work provides useful information regarding the influence that the composition of biogenic model greases has on friction and wear behaviors in a tribological contact.

Freeze-drying, until now, has been a process that was designed using a trial and error experimental approach. This approach is often material and time consuming, and the resulting freeze-drying processes are neither optimum nor robust. Accordingly, the objective of this study was to develop a simple-to-use and experimental-based approach to design an optimum and robust freeze-drying process for any given formulation. The temperature ramp approach (TRA) detailed in this study involves the implementation of a customized design of experiments (DoE) to perform few (three or four) experiments using a given drug formulation. The DoE results are analyzed to define optimum processing conditions (i.e., shelf temperature and chamber pressure) based on a predefined range of target product temperature for primary drying, which could be defined from formulation characterization at its frozen state. In this study, a successful freeze-drying process of two model formulations using the TRA was designed. Verification experiments at the optimum processing conditions showed excellent agreement in both product temperature and sublimation rate with the values obtained using the TRA. Thus, the TRA detailed in this study offers a significant advantage to reduce development time and material, and enhance the efficiency and robustness of the resulting freeze-drying process.

As well known, cellulose fibers, defibrillated/activated in different degrees or even chemically modified, can be employed as additives in matrixes of different nature with the aim of modulating some properties such as the mechanical resistance, rheological behavior or hydrophobicity of the product. Consequently, there is an increasing interest in the incorporation of these materials in a wide variety of products, being necessary the development of green methodologies for their chemical modification. The objective of this work is the use of the ball milling technology as tool for the activation and chemical modification of cellulose fibers, specifically of cellulosic material from jute. The traditional method used to date for the NCO-functionalization of cellulose fibers requires a solvent as reaction medium, the action of a catalyst and a previous stage of mercerization to boost the reactivity of the fibers. Accordingly to the former, jute fibers were NCO-functionalized, on one side, evading previous mercerization and, on other side, applying two different alkali-based activation pre-treatments that lead to materials with different crystallinity index. In addition to this, and after having optimized milling conditions, both activation and NCO-functionalization were successfully carried out in a planetary ball mill avoiding solvent, catalyst and previous alkalization. Cellulose fibers esterification was successfully implemented over already ball milled cellulosic material, showing that activation and chemical modification do not need to be performed at the same time. Fourier transform infrared spectroscopy provided the follow-up of each reaction and the impact of ball milling on the fibers was analyzed by hydrodynamic diameter measurements. Thus, it is demonstrated that ball milling can be proposed as an efficient and environmentally friendly methodology for the activation and/or functionalization of cellulose fibers. ispartof: Cellulose vol:27 issue:2 pages:643-656 status: Published online

Nowadays, different types of natural carbohydrates such as sugars, starch, cellulose and their derivatives are widely used as renewable raw materials. Vegetable oils are also considered as promising raw materials to be used in the synthesis of high quality products in different applications, including in the adhesive field. According to this, several bio-based formulations with adhesion properties were synthesized first by inducing the functionalization of cellulose acetate with 1,6-hexamethylene diisocyanate and then mixing the resulting biopolymer with a variable amount of castor oil, from 20% to 70% (wt). These bio-based adhesives were mechanically characterized by means of small-amplitude oscillatory torsion measurements, at different temperatures, and standardized tests to evaluate tension loading (ASTM-D906) and peel strength (ASTM-D903). In addition, thermal properties and stability of the synthesized bio-polyurethane formulations were also analyzed through differential scanning calorimetry and thermal gravimetric analysis. As a result, the performance of these bio-polyurethane products as wood adhesives were compared and analyzed. Bio-polyurethane formulations exhibited a simple thermo-rheological behavior below a critical temperature of around 80–100 °C depending on the castor oil/cellulose acetate weight ratio. Formulation with medium castor oil/biopolymer weight ratio (50:50 % wt) showed the most suitable mechanical properties and adhesion performance for bonding wood., This work is part of two research projects (CTQ2014-56038-C3-1R and TEP-1499) sponsored by MINECO-FEDER and Junta de Andalucía programmes, respectively. One of the authors (Adri án Tenorio) has also received a PhD. Research Grant from ‘Ministerio de Educación’ (FPU13/01114). The authors gratefully acknowledge the financial support.

13 páginas, 6 figuras, 7 tablas, The toxin profile and hemolytic activity of a strain of Ostreopsis cf. ovata (UFBA013) isolated from Todos os Santos Bay (northeastern Brazil) were evaluated under different levels of N and P. Phylogenetic analyses based on ITS rDNA region (ITS1-5.8S-ITS2) placed UFBA013 within the Atlantic/Mediterranean/Pacific clade of O. cf. ovata. Growth experiments were conducted in f/2 medium modified by adding N and P (P: 0–36 μM; N: 0–882 μM). The growth kinetics was adequately described by logistic equations. The best growth (highest Gm) was recorded under levels of N/P = 0/18, 129/5 and 441/36, while one of the lowest Gm was obtained under P-depletion. The maximum and specific maximum growth rates (as vm; cells mL−1 d−1 and μm; d−1) were achieved with N limitation (N/P = 441/36) and P-limitation/depletion (753/5.3 and 441/0) and are the highest values reported in the literature, most similar to isolates from Pacific and Mediterranean areas. The control experiment (N/P = 441/18) also yielded similar values to those from some Mediterranean isolates, but higher than formerly reported for Brazilian isolates. In all conditions assayed, no palytoxin (PLTX) was detected. The ovatoxins (OVTXs) a, b, c, d and e did not show significant differences in cell quota between exponential and stationary phases. A significant relationship was detected between OVTXs concentration and hemolytic activity, This study was supported by FAPESB - RED0006/2012 and CNPq (Productivity Scholarship in Research # 07368/2015-7) granted to J.M.C. Nunes; CNPq (research grant # 471303/2013-5) to M. Menezes; CAPES (PhD scholarship # 9947-14-14-0/2014) and FAPESB (PhD scholarship Bol. # 10685/2013) to M.C.Q. Mendes

In this study, food emulsions of oil in water from sesame (Sesamum indicum) protein isolates and their oil were formulated and standardised. The effect of the concentrations of sesame (Sesamum indicum) protein isolates and base oil and the speed of the emulsification process for the food emulsion stability was studied. The protein isolates were achieved from the defatted sesame flour (DSF), obtaining a percentage of 80% ± 0.05% of protein. Emulsions were formulated through a factorial design 23. The rheological behaviour of sesame (Sesamum indicum) protein isolates-stabilised emulsions and microstructural composition were investigated. Stable emulsions with suitable rheological properties and microstructure were formulated at a concentration of 10% sesame oil and different concentrations of protein isolates, between 1.5% and 2.5%, with the best droplet distribution characteristics being shown for the 2.5% sesame protein isolates. The emulsions showed a non-Newtonian fluid behaviour, adjusting the Sisko model.

In this work, model renewable and biodegradable lubricating greases based on castor oil and chemically modified biopolymers (methylcellulose, chitin and cellulosic pulp) were tribologically characterized in a steel–steel ball-on-plates tribological cell coupled to a controlled-stress rheometer, and the results were compared to those provided by conventional lithium and calcium soap-based greases. Viscous flow, sliding velocity sweep and transient friction tests were carried out and resulting wear scars in the steel plates were evaluated by means of scanning electron microscopy (SEM). Different frictional responses were found depending on the thickener, especially at high temperature. Excepting for most severe conditions, wear is negligible when using chemically modified chitin and methylcellulose-based greases as lubricants., This work is part of two research projects (CTQ2014-56038-C3-1R and TEP-1499) sponsored by MINECO-FEDER and Junta de Andalucia programmes, respectively. One of the authors (Rocio Gallego) has received a Ph.D. Research Grant (BES-2011-045029) from DIGICyT (MINECO). The authors gratefully acknowledge the financial support. Maria Teresa Cidade acknowledges the support of the Portuguese Foundation for Science and Technology through Project PEst-C/CTM/LA0025/2013 and The Portuguese Society of Rheology (SPR) for her stay in University of Huelva.

The microstructure of lubricating greases greatly conditions their in-service performance. In that sense, optimal testing protocols are required in order to accomplish their correct morphological characterization. This study explores and compares the suitability of atomic force microscopy (AFM) and scanning electron microscopy (SEM) techniques for imaging six different commercial metallic soap-based greases and two novel biopolymer-based formulations. Pros and cons of both techniques and the effect of sample preparation protocol were analysed. The results revealed a wide variety of morphological characteristics depending on composition. Thus, the four anhydrous calcium-based greases demonstrated two clearly distinct microstructures (fibrous and granular) determined by the type of base oil employed. With regard to the lithium complex greases, the typically reported microstructure characterized by well-defined entangled and fibrous network was observed in both AFM and SEM techniques. As for the two biopolymer-based greases, fibre networks were also encountered. Besides this, selected greases were subjected to different tribological tests, and the effect of high-shear frictional working treatments on their microstructure was also analysed. As a result of the friction and internal wear, the AFM results evidenced microstructural changes which depended on grease composition. Overall, the combined use of AFM and SEM techniques was demonstrated to be a powerful approach to microstructurally characterize lubricating greases., This work is part of two research projects (CTQ2014-56038-C3-1R and TEP-1499) sponsored by MINECO-FEDER and Junta de Andalucia programmes, respectively. The authors gratefully acknowledge the financial support. Authors also acknowledge Castrol (Germany) and Verkol S.A. (Spain) for kindly providing commercial samples.

14 páginas, 7 figuras, 5 tablas, Among toxin-producing dinoflagellates of the genus Alexandrium, Alexandrium ostenfeldii is the only species able to produce paralytic shellfish poisoning (PSP) toxins, spirolides (SPXs) and gymnodimines (GYMs). In this study we characterized and compared three A. ostenfeldii strains isolated from the Baltic, Mediterranean, and southern Chile Seas with respect to their toxin profiles, morphology, and phylogeny. Toxin analyses by HPLC–FD and LC–HRMS revealed differences in the toxin profiles of the three strains. The PSP toxin profiles of the southern Chile and Baltic strains were largely the same and included gonyautoxin (GTX)-3, GTX-2, and saxitoxin (STX), although the total PSP toxin content of the Chilean strain (105.83 ± 72.15 pg cell−1) was much higher than that of the Baltic strain (4.04 ± 1.93 pg cell−1). However, the Baltic strain was the only strain that expressed detectable amounts of analogues of GYM-A and GYM-B/-C (48.27 ± 26.12 pg GYM-A equivalents cell−1). The only toxin expressed by the Mediterranean strain was 13-desmethyl SPX-C (13dMeC; 2.85 ± 4.76 pg cell−1). Phylogenetic analysis based on the LSU rRNA showed that the studied strains belonged to distinct molecular clades. The toxin profiles determined in this study provide further evidence of the taxonomic complexity of this species, This work is a contribution of Unidad Asociada “Microalgas Nocivas” (CSIC-IEO) and was carried out at the Instituto Español de Oceanografía (IEO) in Vigo and was financially supported by the CCVIEO project and CICAN-2013-40671-R (Ministry of Economy and Competitiveness). P. Salgado is a researcher at the IFOP, which provides financial support for his doctoral staying

19 páginas, 6 tablas, 4 figuras.-- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited, Alexandrium ostenfeldii is present in a wide variety of environments in coastal areas worldwide and is the only dinoflagellate known species that produces paralytic shellfish poisoning (PSP) toxins and two types of cyclic imines, spirolides (SPXs) and gymnodimines (GYMs). The increasing frequency of A. ostenfeldii blooms in the Baltic Sea has been attributed to the warming water in this region. To learn more about the optimal environmental conditions favoring the proliferation of A. ostenfeldii and its complex toxicity, the effects of temperature and salinity on the kinetics of both the growth and the net toxin production of this species were examined using a factorial design and a response-surface analysis (RSA). The results showed that the growth of Baltic A. ostenfeldii occurs over a wide range of temperatures and salinities (12.5–25.5°C and 5–21, respectively), with optimal growth conditions achieved at a temperature of 25.5°C and a salinity of 11.2. Together with the finding that a salinity > 21 was the only growth-limiting factor detected for this strain, this study provides important insights into the autecology and population distribution of this species in the Baltic Sea. The presence of PSP toxins, including gonyautoxin (GTX)-3, GTX-2, and saxitoxin (STX), and GYMs (GYM-A and GYM-B/-C analogues) was detected under all temperature and salinity conditions tested and in the majority of the cases was concomitant with both the exponential growth and stationary phases of the dinoflagellate’s growth cycle. Toxin concentrations were maximal at temperatures and salinities of 20.9°C and 17 for the GYM-A analogue and > 19°C and 15 for PSP toxins, respectively. The ecological implications of the optimal conditions for growth and toxin production of A. ostenfeldii in the Baltic Sea are discussed, This work is a contribution of the Unidad Asociada "Microalgas Nocivas" (CSIC-IEO) and was financially supported by the CCVIEO project and CICAN-2013-40671-R (Ministry of Economy and Competitiveness). P. Salgado is a researcher at IFOP, which has provided financial support for his doctoral stay

The fine scale vertical distribution of Dinophysis spp. and Protoceratium reticulatum (potential producers of lipophilic shellfish toxins, LSTs) and its relation with LSTs in shellfish was studied in Reloncaví fjord, a strongly stratified system in Southern Chile. Samples were taken over two years from late spring to early autumn (2007–2008 period) and from early spring to late summer (2008–2009 period). Dinophysis spp., in particular Dinophysis acuminata, were always detected, often forming thin layers in the region of the salinity driven pycnocline, with cell maxima for D. acuminata of 28.5×103 cells L−1 in March 2008 and 17.1×103 cells L−1 in November 2008. During the 2008–2009 sampling period, blooms of D. acuminata co-occurred with high densities of cryptophyceans and the ciliate Mesodinium spp. The highest levels of pectenotoxin-2 (PTX-2; 2.2 ng L−1) were found in the plankton in February 2009, associated with moderate densities of D. acuminata, Dinophysis tripos and Dinophysis subcircularis (0.1–0.6×103 cells L−1). However, only trace levels of PTX-2 were observed in bivalves at that time. Dinophysistoxin (DTX-1 and DTX-3) levels in bivalves and densities of Dinophysis spp. were not well correlated. Low DTX levels in bivalves observed during a major bloom of D. acuminata in March 2008 suggested that there is a large seasonal intraspecific variability in toxin content of Dinophysis spp. driven by changes in population structure associated with distinct LST toxin profiles in Reloncaví fjord during the study period. A heterogeneous vertical distribution was also observed for P. reticulatum, whose presence was restricted to summer months. A bloom of this species of 2.2×103 cells L−1 at 14 m depth in February 2009 was positively correlated with high concentrations of yessotoxins in bivalves (51–496 ng g−1) and plankton samples (3.2 ng L−1). Our results suggest that a review of monitoring strategies for Dinophysis spp. in strongly stratified fjord systems should be carried out. They also indicate that early warning of LST events based on Dinophysis cell numbers are not reliable for seafood control., This study was supported by FONDECYT (Chile) grant 1070706, 11 páginas, 8 figuras, 1 tabla.-- Catharina Alves-de-Souza ... et al.

13 páginas, 8 tablas, 6 figuras, The toxicity of Alexandrium andersonii Balech is unclear and its intraspecific variability has yet to be studied. To address these gaps in our knowledge, in the present work five strains of A. andersonii from four different localities were characterized. The results showed that despite genetic homogeneity in the 5.8-ITS (internal transcribed spacer) and large subunit (LSU) regions and similar growth rates, strains originating from different locations varied with respect to cell size, the ratios of certain pigments, and their growth patterns. Cultures of the strains grown at 20 °C were analyzed for toxicity using four different methodologies. The two officially established methods, mouse bioassay and high-performance liquid chromatography with fluorescence detection (HPLC-FLD) and post-column reaction analysis of PSP toxins, failed to show the toxicity of any strain. Strains grown at 14 °C were also negative for PSP toxins by HPLC-FLD. However, strains grown at 20 °C exhibited both a response characteristic of the presence of toxin-inhibiting voltage-gated sodium channels, as demonstrated in a neuroblastoma neuro-2a cell-based assay, as well as hemolytic activity in a sheep red blood cell assay., Financial support was provided by the Agència Catalana de l’Aigua (Department de Medi Ambient, Generalitat de Catalunya) and the CSIC through the contract “Pla de vigilància de fitoplàncton nociu i tòxic a la Costa Catalana;” by the “Xarxa de Referència de Recerca i Desenvolupament en Aqüicultura”; project JACUMAR/2007/SANIDAD ANIMAL/PSP2; and project PRIN 2009, financed by the Italian Ministry of Education, University and Research

This work deals with the chemical, thermal and viscous characterization of a variety of estolides, prepared from higholeic sunflower and olive pomace acid oils, using different acid-catalyzed synthesis protocols and reaction times. Estolides with weight-average molecular weights between 1.7 and 3.4 times higher than the original acid oils were obtained. The molecular weight of the estolides was higher when using the sulphuric acid-catalyzed method and a reaction time of 3-6 h. Estolides presented higher freezing temperatures than acid oils. In general, viscosity values are related to estolide molecular weight. Significant increments in viscosities were found in comparison with acid oils. Maximum viscosity values were obtained for estolides prepared using the sulphuric acidcatalyzed method. The largest viscosity increments in olive pomace acid oil-derived estolides were observed during the first 6 hours of reaction, due to an increase in the molecular weight; longer reaction times yielded adverse results. The temperature dependence of viscosity for all estolides studied is significantly larger than for the original acid oils., Este trabajo presenta la caracterización química, térmica y viscosa de estólidos preparados a partir de oleínas ácidas de girasol alto-oleico y de orujo de oliva, utilizando diferentes métodos catalizados por ácidos y diferentes tiempos de reacción. Se obtuvieron estólidos con pesos moleculares promedios en peso entre 1,7 y 3,4 veces más altos que las oleínas de origen. El peso molecular de los estólidos aumenta cuando se utiliza el método catalizado por ácido sulfúrico y un tiempo de reacción de 3-6 h. Los estólidos obtenidos presentan temperaturas de congelación más altas que las oleínas. En general, los valores de viscosidad están relacionados con el peso molecular del estólido. Se encontraron incrementos significativos de viscosidad en comparación con las oleínas. Los valores máximos de viscosidad se obtuvieron para los estólidos preparados con el método catalizado por ácido sulfúrico. En los estólidos derivados de oleína de orujo de oliva se observaron los mayores incrementos de viscosidad durante las 6 primeras horas de reacción, debido al mayor aumento en el peso molecular. Tiempos más largos de reacción dan lugar a resultados desfavorables. La dependencia de la viscosidad con la temperatura de todos los estólidos es más importante que en las oleínas de partida., This work is part of a research project (CTQ2010-15338) sponsored by a MINECO-FEDER programme (70% European cofunding rate). The authors gratefully acknowledge its financial support.

In this work, the use of different cellulosic pulp samples to prepare new formulations potentially applicable as biodegradable lubricating greases is explored. Cellulosic pulps from different raw materials and submitted to different pulping process and/or several acidic treatments were characterized and used as biothickener agents to formulate gel-like dispersions. Cellulose pulp samples mainly differed in polymerization degree (160-893 cm3/g) and lignin (0.3-27.1% w/w) and α-cellulose (46.0-85.1% w/w) contents. Rheological measurements and some standard mechanical tests usually performed with lubricants were carried out. The rheological response of cellulosic pulp-based gel-like dispersions is mainly a consequence of the balance between the cellulose polymerization degree and lignin and α-cellulose contents, independently on the origin of cellulose samples and pulping treatment. An empirical correlation between a power function of these variables and the plateau modulus has been proposed to predict the rheological behavior of resulting formulations. However, cellulosic pulp-based dispersions studied generally present either poor mechanical stability or low consistency indexes than expected for lubricating greases. © 2011 American Chemical Society.

Oleogels based on sorbitan and glyceryl monostearates and different types of vegetable oils, potentially applicable as biodegradable alternatives to traditional lubricating greases, have been studied. In particular, the rheological behavior, by means of small-amplitude oscillatory shear (SAOS) measurements, and some lubrication performance-related properties (mechanical stability and tribological response) have been evaluated in this work. SAOS response and mechanical stability of these oleogels are significantly influenced by the type and concentration of the organogelator and the vegetable oil used in the formulations. Glyceryl monostearate (GMS) generally produces stronger gels than sorbitan monostearate (SMS). The use of low-viscosity oils, such as rapeseed and soybean oils, yields gels with significantly higher values of the linear viscoelastic functions than oleogels prepared with high-viscosity oils, i.e. castor oil. The rheological behavior of SMS-based oleogels also depends on the cooling rate applied during the gelification process. On the other hand, the oleogels studied present low values of the friction coefficient obtained in a tribological contact, although only some GMS/castor oil-based oleogels exhibit a suitable mechanical stability. En el presente trabajo se han estudiado diferentes oleogeles, basados en monoestearatos de sorbitano y glicerilo y aceites vegetales, que podrían ser potencialmente empleados como alternativas biodegradables a las grasas lubricantes tradicionales. En concreto, se ha evaluado su comportamiento reológico, a través de ensayos en cizalla oscilatoria, y algunas propiedades relacionadas con su rendimiento en la lubricación, tales como su estabilidad mecánica y comportamiento tribológico. La respuesta reológica y la estabilidad mecánica de los oleogeles estudiados están significativamente influenciadas por el tipo y la concentración del agente gelificante y por el aceite vegetal empleado. Así, el monoestearato de glicerilo (GMS) produce, generalmente, geles más fuertes que el monoestearato de sorbitano (SMS). El uso de aceites de baja viscosidad, como los aceites de colza o de soja, dan lugar a geles con valores más altos de las funciones viscoelásticas lineales que los oleogeles preparados con aceite de ricino. El comportamiento reológico de los oleogeles de SMS depende, además, de la velocidad de enfriamiento durante la gelificación. Por otra parte, los oleogeles estudiados presentan bajos valores del coeficiente de fricción, determinado en un contacto tribológico, aunque sólo algunos oleogeles que contienen GMS y aceite de ricino muestran una estabilidad mecánica adecuada. This work is part of two research projects (CTQ2007-60463/PPQ and PSE-420000-2008-4) sponsored by MICINN-FEDER Programmes. Thanks are also given to Prof. E. Kuhn (University of Applied Sciences of Hamburg, Germany) for his technical support by performing the tribological tests.

The diversity of Alexandrium spp. in Irish coastal waters was investigated through the morphological examination of resting cysts and vegetative cells, the determination of PSP toxin and spirolide profiles and the sequence analysis of rDNA genes. Six morphospecies were characterised: A. tamarense, A. minutum, A. ostenfeldii, A. peruvianum, A. tamutum and A. andersoni. Both PSP toxin producing and non-toxic strains of A. tamarense and A. minutum were observed. The average toxicities of toxic strains for both cultured species were respectively 11.3 (8.6 S.D.) and 2.3 (0.5 S.D.) pg STX equiv. cell−1. Alexandrium ostenfeldii and A. peruvianum did not synthesise PSP toxins but HPLC–MS analysis of two strains showed distinct spirolide profiles. A cyst-derived culture of A. peruvianum from Lough Swilly mainly produced spirolides 13 desmethyl-C and 13 desmethyl-D whereas one of A. ostenfeldii, from Bantry Bay, produced spirolides C and D. Species identification was confirmed through the analyses of SSU, ITS1-5.8S-ITS2 and LSU rDNA genes. Some nucleotide variability was observed among clones of toxic strains of A. tamarense, which all clustered within the North American clade. However, rDNA sequencing did not allow discrimination between the toxic and non-toxic forms of A. minutum. Phylogenetic analysis also permitted the differentiation of A. ostenfeldii from A. peruvianum. Resting cysts of PSP toxin producing Alexandrium species were found in Cork Harbour and Belfast Lough, locations where shellfish contamination events have occurred in the past, highlighting the potential for the initiation of harmful blooms from cyst beds. The finding of supposedly non-toxic and biotoxin-producing Alexandrium species near aquaculture production sites will necessitate the use of reliable discriminative methods in phytoplankton monitoring., SI

15 pages, 9 figures , 2 tables, A mixed community composed of a non-toxic form of Alexandrium tamarense and a paralytic shellfish poisoning (PSP) toxin-producing A. minutum develops on an annual basis in Cork Harbour, Ireland. The understanding of the ecological mechanisms that influence the population dynamics of these bloom-forming species is fragmentary, partly due to the difficulty in the discrimination between Alexandrium species in mixed phytoplankton assemblages by conventional light microscopy. During 2 surveys carried out in the estuary in July and September 2005, taxon-specific large subunit rRNA targeted probes were used in a whole-cell fluorescent in situ hybridisation assay to facilitate the detection and quantification of Alexandrium spp. in seawater samples. The Alexandrium spp. concentrations derived with molecular probes were on average half those obtained using an Utermöhl sedimentation chamber and calcofluor. Results showed the dominance of A. tamarense over A. minutum in July and an almost exclusive presence of A. minutum in September. Alexandrium spp. did not quantitatively dominate the total dinoflagellate assemblage and cell concentrations were lower than those found in bloom situations, nonetheless reaching more than 1 × 104 cells l–1 locally on both occasions. The PSP toxins GTX3 and GTX2 were detected in all field samples, concentrations being associated with greater abundances of A. minutum in September. Despite probable inaccuracies inherent in the sampling methodology, the estimated intracellular toxin quotas in A. minutum were higher in the areas of the estuary that connected different water bodies and where cells may be subjected to regimes of high turbulence and rapid changes of salinity and temperature, This work was supported by the Higher EducationAuthority of Ireland (PRTLI Cycle III) and by the EC 6thFramework Programme through the SEED project (GOCE-CT-2005-003375)

30 páginas, 9 figuras, 2 tablas., Yessotoxin (YTX) is a marine polyether toxin that was first isolated in 1986 from the scallop Patinopecten yessoensis. Subsequently, it was reported that YTX is produced by the dinoflagellates Protoceratium reticulatum, Lingulodinium polyedrum and Gonyaulax spinifera. YTXs have been associated with diarrhetic shellfish poisoning (DSP) because they are often simultaneously extracted with DSP toxins, and give positive results when tested in the conventional mouse bioassay for DSP toxins. However, recent evidence suggests that YTXs should be excluded from the DSP toxins group, because unlike okadaic acid (OA) and dinophyisistoxin-1 (DTX-1), YTXs do not cause either diarrhea or inhibition of protein phosphatases. In spite of the increasing number of molecular studies focused on the toxicity of YTX, the precise mechanism of action is currently unknown. Since the discovery of YTX, almost forty new analogues isolated from both mussels and dinoflagellates have been characterized by NMR or LC-MS/MS techniques. These studies indicate a wide variability in the profile and the relative abundance of YTXs in both, bivalves and dinoflagellates. This review covers current knowledge on the origin, producer organisms and vectors, chemical structures, metabolism, biosynthetic origin, toxicological properties, potential risks to human health and advances in detection methods of YTXs., Authors acknowledge financial support from the Spanish MEC (AGL2005-07924-C04-01 and 02/ALI), INIA (ACU-02-005) and CCVIEO projects.

17 páginas, 12 figuras, 1 tabla, In 2005, a bloom of the Diarrhoetic Shellfish Poisoning (DSP) causative agent Dinophysis acuta Ehrenberg in the Galician Rías Baixas (NW Spain) started in early August and reached maximum densities (up to 2 × 104 cell l–1) in mid November. A cell cycle study was carried out over a 22 h period on 9 and 10 November to describe the physiological status and the short-term variability in cell toxin quota of D. acuta at the time of the annual maximum of lipophilic toxins in shellfish. At that time, the population of D. acuta showed an extremely low division rate (μ = 0.03 d–1), a high frequency of dead cells (up to 15%) and cells with starch granules (up to 93%), and no evidence of recent mixotrophic behaviour. Still, the cells, which did not perform vertical migration, aggregated around salinity-driven density discontinuities in the top 5 m and had a high cell toxin quota (determined by liquid chromatography-mass spectrometry) for this species. A 3.5-fold difference was found between maximum (during the night) and minimum values of cell toxin quota. Okadaic acid (OA) was the predominant toxin and changes in cell quota of different toxins showed different daily patterns in the content of okadaiates and pectenotoxins; thus, the toxin profile is influenced by the time of sampling. Dissolved toxins (adsorbed by resins in passive samplers from 8 to 14 November) also reached annual maxima and reflected the vertical distribution of D. acuta cells. These results emphasize the need to parameterize physiological conditions and behaviour of Dinophysis populations during different phases of the population growth and hydrodynamic scenarios, This research was supported by projects ‘Dinophysis Galicia’ (CTM2004-0478- CO3-01) and ‘HABIT’ (EU GOCE-CT-2005-003932) to B.R. and project AGL 2005-07924-C04-02 to J.M.F. G.P. was funded by a Chilean pre-doctoral fellowship from the Centro de Estudios del Quaternario Fuego-Patagonia y Antartica (CEQUA) Foundation and the Instituto de Fomento Pesquero (IFOP).

The physiological response of the PSP toxin producing dinoflagellate Alexandrium minutum isolated from the Irish coast was assessed after modulating the initial concentrations of nitrate and phosphate in batch cultures. The cell growth in cultures of strain CK.A02 was primarily controlled by nitrate availability. In all experiments, only gonyautoxins 2 and 3 (GTX2 and 3) were synthesized along the different growth phases, with GTX3 dominating (≈80%) at all stages, making the GTX2–3 toxin profile a possible population marker of A. minutum in Cork Harbour. The cellular toxin quotas remained low and relatively stable at around 2 pg cell−1, except when high N:P ratios were initially used for culture inoculations; in these conditions PSP toxins accumulated up to 14 pg cell−1. Due to the composition of the toxin profile, the toxicity of strain CK.A02 was generally relatively low (from 1.1 to 1.7 pg STX eq cell−1) in comparison with strains from other geographic areas except when phosphate limiting culture conditions were applied (maximum of 12.5 pg STX eq cell−1). Results showed that sufficient soluble protein quotas were necessary to observe the intra-cellular accumulation of PSP toxins in phosphate limiting conditions, highlighting also the requirement of adequate nitrogen supplies. The possible existence of localized toxicity hot spots in the field, linked to the accumulation of PSP toxins within A. minutum cells as a metabolic response to adverse environmental conditions, could potentially increase risks for shellfish farming operations, SI

The toxin composition of a culture of the dinoflagellate Protoceratium reticulatum was investigated using LC–FLD, after derivatization with DMEQ-TAD (4-(2-(6,7-dimethoxy-4-methyl-3-oxo-3,4-dihydroquinoxalimylethyl)-1,2,4-triazoline-3,5-dione)). Besides yessotoxin (YTX), the new YTX analogue, glycoyessotoxin A (G-YTXA) was detected in culture medium as well as in cells. The conditions for extraction were optimized and the production profile established. Retention time of the resulting fluorescent G-YTXA adduct was identified by comparison of the appropriate standard. Additionally, both G-YTXA and the DMEQ-TAD-G-YTXA adduct were confirmed by LC–MS showing ion peaks at m/z 1273 [M−2Na+H]− and m/z 1618 [M−2Na+H]−, respectively. The LC–MSn displayed a fragmentation pattern similar to that of the YTX series., SI

7 pages, 4 tables, 7 figures, A rapid liquid-chromatography (LC) method is presented which uses fluorescence detection (FLD) for palytoxin analogues analysis in benthic dinoflagellates of the genus Ostreopsis. The amino-acidic reagent 6-aminoquinolyl-N-hydroxisuccinimidyl carbamate (AccQ) was used for fluorescence labelling followed by LC–FLD. The efficacy of the method is exemplified by comparison of the results of the quantification obtained by LC–FLD and the hemolytic assay performed for palytoxins for which a highly significant linear correlation was achieved (r2 = 0.9118). The derivatized palytoxin analogues were determined in the range of 0.75–25 ng. The proposed method was successfully applied to the determination and quantification of palytoxin analogues in 14 samples from different strains of Ostreopsis from different locations (Western Mediterranean Sea, Canary Islands, Madeira Islands and Southern coasts of Brazil). To confirm the chemical structure of the toxins, samples were also analyzed by liquid chromatography coupled with mass spectrometry (LC–MS) with a system that has a poorer sensitivity when compared with LC–FLD detection and the hemolytic assay. The successful use of this method with dinoflagellates is a good indicator of suitability for other types of marine samples, Project CICYT REN2001-2959-CO4-01/MAR supported this work

7 páginas, 3 figuras, 1 tabla, Marine planktonic dinoflagellates are usually associated with bacteria, some of which seem to have a symbiotic relation with the dinoflagellate cells. The role of bacteria in dinoflagellate life cycles is not well known and their influence on toxin production is controversial. The potential relationship between dinoflagellate-associated bacteria and toxin production was experimentally investigated by identifying and comparing bacterial populations present in toxic (AL1V) and non-toxic (AL4V) strains of Alexandrium minutum. Part of the 16S rDNA of the bacteria associated with these clones was PCR amplified, cloned and sequenced, in order to identify the bacterial species present in each culture. Results indicated that most of the bacteria species were present in the cultures of both A. minutum clones, but some were specific to either the toxic or the non-toxic clone. Some, but not all bacteria identified were also isolated, and appropriate conditions for their culture were developed as a first step in assessing their role in the growth and toxin production by A. minutum., LP was funded through a fellowship from the Comunidad de Madrid. This work was supported by grant CTM2004-04078.C03-03/MAR from the Ministerio de Educación y Ciencia awarded to IM, and an institutional grant from Fundación Ramón Areces to the Centro de Biologia Molecular ‘Severo Ochoa’.

3 páginas, 2 figuras, 1 tabla, The dinoflagellate Protoceratium reticulatum produces toxins of the yessotoxin group currently included in the diarrhetic shellfish poisoning class. In this paper we report on the isolation and structural elucidation of a 32-arabinoside of yessotoxin, G-YTXA (2), obtained from laboratory cultures of P. reticulatum (strain GG1AM) that possesses a pentose unit, â-arabinofuranose, as a side chain., The authors acknowledge financial support from MCYT (REN 2001-2959-C04-01 and -02; PPQ2002- 04361-C04-04); MCYT-FSE (Programa Ramo´n y Cajal, M.L.S.).

The rheological behavior and stability of oil-in-water emulsions was studied. The addition of different thickening agents improved the stability of the emulsions, and the presence of hydrocolloids caused their flocculation. Their viscoelastic behavior was described on the basis of stress relaxation curves and shear strains. Fil: Quintana, Juan Manuel. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentina Fil: Califano, Alicia Noemi. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentina Fil: Zaritzky, Noemi Elisabet. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentina. Universidad Nacional de La Plata. Facultad de Ingenierí­a. Departamento de Ingeniería Química; Argentina Fil: Partal, P.. Universidad de Huelva; España Fil: Franco, J.M.. Universidad de Huelva; España

16 páginas, 4 tablas, 7 figuras, The accumulation of paralytic shellfish poisoning (PSP) toxins by bivalves is a serious threat to public health all over the world. However, very little is known about the uptake kinetics of these toxins and the environmental factors that may modify this process. We have studied the effect of mussel size, temperature, seston volume, food quality, and volume-specific toxin concentration (VOSTOC), on the uptake rate of paralytic shellfish poisoning (PSP) toxins by mussels (Mytilus galloprovincialis), by means of a second order factorial experiment. Over a 3-day period, the mussels were fed artificial diets containing Alexandrium minutum AL1V (a PSP toxin producer), Tetraselmis suecica, Ensiculifera sp1 and silt, to the levels required by each treatment. Mussel size, seston volume and VOSTOC were found to be statistically significant when the total toxin accumulated per weight of wet tissue was considered. Mussel size affected the uptake negatively and latter two positively. The interactions, mussel size–VOSTOC and mussel size–food quality were also significant. The response was not linear as shown by the significance of the quadratic term of mussel size. Notwithstanding, when the PSP toxins accumulation per mussel was analysed, only one factor, the VOSTOC and the interactions, food quality–mussel size and food quality– seston volume, were found to be significant. VOSTOC was the most important factor in the accumulation of toxins, in our opinion, probably due to toxin assimilation being mainly regulated by the probability of contact between the toxins and the cellular walls of the digestive system. The size of the bivalve is also especially important because toxin concentration is usually calculated per weight of bivalve tissue and because the weight-specific ingestion increases with mussel size. The food quality, which was directly related to the assimilation of organic matter, had an inverse effect on toxin assimilation. In our opinion, this is probably due to the effect of inorganic particles in enhancing the disruption of Alexandrium cells. Temperature had no effect on the uptake rate except for the accumulation of the gonyautoxin GTX1.

7 páginas, 7 figuras, 1 tabla, In order to clarify the origin of Paralytic Shellfish Toxins occurring in the ormers, Haliotis tuberculata, various studies were conducted to describe toxicity distribution by area, length and parts of the mollusc. Ormer toxicity from different locations of the Galician coast had a confidence interval of 252925 mg STX eq:100 g of meat (mg of equivalents of saxitoxin:100 g) by mouse bioassay analyses and 454986 mg STX eq:100 g of meat by High Performance Liquid Chromatography (HPLC). No value of below 140 mg STX eq:100 g of meat was detected. No significant differences were observed among locations for the values obtained by HPLC, while some differences were found by mouse bioassay. Toxin composition showed decarbamoylsaxitoxin (dcSTX) as the most abundant component (83–100%) with saxitoxin (STX) in a much smaller proportion. Significant differences were observed in the toxin content for the different length groups, toxin content increasing very significantly in the largest ormers, of over 85 mm. Toxin analyses in the different parts of the mollusc by HPLC showed significantly high values for the epithelium of the foot in comparison with the gut and the rest of the mollusc. They reached 105 102915 102 mg of toxin:100 g of epithelium, against 2895 mg of toxin:100 g of gut and 2796 mg of toxin:100 g of muscle. Considering the weight and the quantity of toxin in each part of the ormer, the epithelium carried 2.6 times more toxin than the muscle, This research was supported by projects MAR95-1849 and ALI95-1012-CO5-01.

7 páginas, 3 figuras, 4 tablas., 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., This work was supported by the Scottish Office Agriculture, Environment and Fisheries Department, Natural Environment Research Council (U.K.), and CICYT project no. ALI 95-1012-CO5-01.

8 páginas, 4 figuras, 1 tabla, An RP-HPLC method for the separation of shellfish toxins is described, employing three isocratic systems: Octanesulfonic acid in ammonium phosphate buffer plus acetonitrile for the separation of carbamate toxins (neoSTX, dcSTX and STX), octansulfonic acid in ammonium phosphate buffer for the separation of GTXs and tetrabutylammonium in the same buffer for Cs separation. These eluents perform the separation prior to postcolumn reaction and fluorimetric detection. The procedures have been applied to the determination of toxin production in dinoflagellate cultures, field samples of red tides, and toxic mussels., This work was financed by Fondo de Investigacion de Sanidad y Seguridad Social, Project 102 of the IEO and by a grant from the Xunta de Galicia to P. Fernandez-Vila.