Applicability of 'Toolkit for Safety Assessment' tool to interventional radiology using probabilistic risk assessment techniques.

Interventional radiology brings extensive benefits to patients. Nevertheless, certain procedures may result in high doses of radiation, leading to health risks to occupationally exposed individuals (OEIs). Therefore, a more comprehensive risk analysis is essential to ensuring safety and minimising radiation exposures for all OEIs. The Toolkit for Safety Assessment (TOKSA) tool performs risk assessments based on the concepts described in 'General Safety Requirements' Part 3 (Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards) and Part 4 (Safety Assessment for Facilities and Activities). This tool was developed based on the 'Ibero-American Forum of Radiological and Nuclear Regulatory Agencies' risk models and can promote the use of the risk assessment processes by OEIs. The aim of this study was to experimentally analyse the applicability of the TOKSA tool in interventional radiology with the use/support of probabilistic risk assessment techniques. The results were used to reduce the risks associated with a hemodynamics room in a hospital in Belo Horizonte, Brazil.

Quantitative proteomic analysis of marine biofilms formed by filamentous cyanobacterium.

Cyanobacterial molecular biology can identify pathways that affect the adhesion and settlement of biofouling organisms and, consequently, obtain novel antifouling strategies for marine applications. Proteomic analyses can provide an essential understanding of how cyanobacteria adapt to different environmental settings. However, only a few qualitative studies have been performed in some cyanobacterial strains. Considering the limited knowledge about protein expression in cyanobacteria in different growing conditions, a quantitative proteomic analysis by LC-MS/MS of biofilm cells from a filamentous strain was performed. Biofilms were also analysed through standard methodologies for following cyanobacterial biofilm development. Biofilms were formed on glass and perspex at two relevant hydrodynamic conditions for marine environments (average shear rates of 4 s-1 and 40 s-1). Biofilm development was higher at 4 s-1 and no significant differences were found between surfaces. Proteomic analysis identified 546 proteins and 41 were differentially expressed. Differences in protein expression were more noticeable between biofilms formed on glass and perspex at 4 s-1. When comparing biofilms formed on different surfaces, results suggest that biofilm development may be related to the expression of several proteins like a beta-propeller domain-containing protein, chaperone DnaK, SLH domain-containing proteins, an OMF family outer membrane protein, and/or additional uncharacterized proteins. Regarding the hydrodynamic effect, biofilm development can be related to SOD enzyme expression, to proteins related to photosynthetic processes and to a set of uncharacterized proteins with calcium binding domains, disordered proteins, and others involved in electron transfer activity. Studies that combine distinct approaches are essential for finding new targets for antibiofilm agents. The characterisation performed in this work provides new insights into how shear rate and surface affect cyanobacterial biofilm development and how cyanobacteria adapt to these different environmental settings from a macroscopic standpoint to a proteomics context.

Mechanical Properties of Topical Anti-Psoriatic Medicines: Implications for Patient Satisfaction with Treatment.

Different types of topical preparations are available as anti-psoriatic medicines, semisolid formulations being the preferred dosage forms for the treatment of body lesions. The mechanical characterization of these semisolid formulations is seldom reported, although mechanical features have been recognized to play an important role in treatment acceptability and adherence. The aim of this study was to characterize the mechanical properties of semisolid topical formulations commercially available for psoriasis treatment. One complementary aim was to evaluate patient satisfaction with topical treatment and discuss the results according to the mechanical features of the dosage form. Eight ointments (O 1-8), five creams (C 1-5), one oleogel (G1), and one excipient (E1-petrolatum) were characterized for textural properties (spreadability and penetration tests) and flow behavior. Power law model was fitted to the results. A questionnaire for the assessment of satisfaction with topical medicines used for psoriasis treatment over 6 months was developed and applied to 79 psoriasis patients. All the tested formulations presented a shear-thinning behavior with power law indexes (n) lower than 1. Ointments were distinct from the other dosage forms, since they presented higher consistency coefficients (K), firmness, and adhesiveness and this was evidenced by hierarchical cluster analysis, which identified two clusters based on the mechanical properties. Cluster 1 included the ointments and petrolatum and the cluster 2 enclosed the creams and the gel. The clusters were associated with several attributes classified by patients as analyzed with Fisher's exact test. In all cases, higher satisfaction was observed for cluster 2. The knowledge obtained regarding the influence of the dosage form on the degree of satisfaction with the treatment could be helpful in supporting the selection of the dosage form in clinical practice and thus improve treatment adherence and clinical outcomes. The differences observed between the mechanical properties of the formulations studied may be also relevant to the industry, as guidance to the development of new medicines.

Efficacy of plants extracts from the Cerrado against adult female of Dermacentor nitens (Acari: Ixodidae).

Dermacentor nitens tick is commonly found in the equine auditory canal, where it causes economic losses due to its direct damage, causing blood spoliation, stress, transmission of pathogens, and predisposition to myasis and secondary bacterial infection in its hosts. In this study we evaluated the effect of ethanolic extracts of Cerrado plants on biological parameters of engorged females of D. nitens. Ethanolic extracts were prepared from the leaves of Schinopsis brasiliensis, Piptadenia viridiflora, Ximenia americana, and Serjania lethalis at 25-150 mg mL-1. Groups of 10 engorged adult females were treated with these extracts and compared with a control containing distilled water and another control with organophosphate, using five replicates for each group. Compared with the control with water, S. lethalis and X. americana extracts at 100 and 150 mg mL-1 significantly inhibited the posture ability. Differently, extracts of S. brasiliensis and P. viridiflora were the most effective in inhibiting larval hatching. Extracts of X. americana and P. viridiflora showed effective inhibition of reproductive parameters of the tick, presenting dose-dependent effect with IC90 78.86 and 78.94 mg mL-1, respectively. Theses effective extracts contained low condensed tannin levels and their HPLC chromatograms revealed the presence of flavonoids. The efficacies of P. viridiflora and X. americana extracts were higher than 90% indicating that these extracts are promising as alternative agents for D. nitens control.

Effects of microcystin-LR and cylindrospermopsin on plant-soil systems: A review of their relevance for agricultural plant quality and public health.

Toxic cyanobacterial blooms are recognized as an emerging environmental threat worldwide. Although microcystin-LR is the most frequently documented cyanotoxin, studies on cylindrospermopsin have been increasing due to the invasive nature of cylindrospermopsin-producing cyanobacteria. The number of studies regarding the effects of cyanotoxins on agricultural plants has increased in recent years, and it has been suggested that the presence of microcystin-LR and cylindrospermopsin in irrigation water may cause toxic effects in edible plants. The uptake of these cyanotoxins by agricultural plants has been shown to induce morphological and physiological changes that lead to a potential loss of productivity. There is also evidence that edible terrestrial plants can bioaccumulate cyanotoxins in their tissues in a concentration dependent-manner. Moreover, the number of consecutive cycles of watering and planting in addition to the potential persistence of microcystin-LR and cylindrospermopsin in the environment are likely to result in groundwater contamination. The use of cyanotoxin-contaminated water for agricultural purposes may therefore represent a threat to both food security and food safety. However, the deleterious effects of cyanotoxins on agricultural plants and public health seem to be dependent on the concentrations studied, which in most cases are non-environmentally relevant. Interestingly, at ecologically relevant concentrations, the productivity and nutritional quality of some agricultural plants seem not to be impaired and may even be enhanced. However, studies assessing if the potential tolerance of agricultural plants to these concentrations can result in cyanotoxin and allergen accumulation in the edible tissues are lacking. This review combines the most current information available regarding this topic with a realistic assessment of the impact of cyanobacterial toxins on agricultural plants, groundwater quality and public health.

Performance, metabolic variables and enteric methane production of Santa Inês hair lambs fed Orbignya phalerata and Combretum leprosum.

In this study, the possibility of using Babassu (Orbignya phalerata) and Mofumbo (Combretum leprosum) leaves for lambs feed was verified. Performance, biochemical and haematological parameters, microbial protein synthesis, nutrient apparent digestibility and enteric production of methane (CH4 ) were evaluated. The experimental treatments included diets with forage-to-concentrate ratios of 50:50, with the leaves of the experimental plants replacing 33% of the Cynodon dactylon (Tifton-85) hay with three treatments: control (no hay replacement) and substitution with Babassu or Mofumbo. For the performance study, 24 Santa Inês lambs were used, in a randomized experimental design with eight repetitions (5 male and 3 female) for each treatment and 48 days of experimental trial. After this period, for nine days, six animals from each treatment were allocated in metabolic cages to determine the apparent nutrient digestibility, microbial protein synthesis and nitrogen balance. Simultaneously, enteric CH4 was measured in vivo. The control group showed higher (p < 0.05) apparent digestibility of acid detergent fibre. Enteric CH4 production of lambs fed Mofumbo leaves did not differ from that of the control group, but was lower (p < 0.05) than in those fed with Babassu. The inclusion of Babassu and Mofumbo leaves showed no negative effects on animal health and did not compromise performance. Mofumbo also presented CH4 mitigating potential, indicating that those plants can be used as ingredients in the composition of lamb diets with the advantage of reducing methane production.

Effects of the naturally-occurring contaminant microcystins on the Azolla filiculoides-Anabaena azollae symbiosis.

Harmful algal blooms (HABs) contaminate aquatic ecosystems and are responsible for animal poisoning worldwide. We conducted a toxicity test with the aquatic fern and the biofertilizer, Azolla filiculoides. The sporophytes were exposed to three concentrations (0.01, 0.1 and 1µgmL(-1)) of a microcystin (MC) cyanobacterial crude extract and purified MC-LR. The growth of A. filiculoides decreased only at 1µgmL(-1) crude extract concentration while with MC-LR it decreased at all the tested concentrations, indicating that the presence of other compounds in the crude extract altered toxicity and stimulated the fern growth at lower concentrations (0.01 and 0.1µgmL(-1)). Both phycoerythrocyanin and allophycocyanin levels decreased in all the concentrations of crude extract and MC-LR. The phycocyanin had a marked increase at 0.1µgmL(-1) crude extract concentration and a marked decrease at 1µgmL(-1) MC-LR concentration. These changes in the phycobiliprotein content indicate a shift in the antenna pigments of the cyanobionts of A. filiculoides. The changes in two oxidative stress enzymes, glutathione reductase for the crude extract assay and glutathione peroxidase for MC-LR assay, points towards the induction of stress defense responses. The low bioconcentration factor in both crude extract and MC-LR treatments can suggest the low uptake of microcystins, and indicates that the aquatic fern can be used as a biofertilizer and as animal feed but is not suitable for MC phytoremediation.

Cylindrospermopsin: occurrence, methods of detection and toxicology.

Cyanobacteria are aquatic micro-organisms that pose a great threat to aquatic ecosystems by the production of dense blooms, but most importantly by the production of secondary metabolites, namely the cyanotoxins. One of these is cylindrospermopsin (CYN), a hepatotoxic polyketide-derived alkaloid with well-known associated cases of animal mortalities and human morbidity. First described as being associated with liver damage, this toxin is now considered a cytotoxic and a genotoxic toxin, due to its effects in other organs and in DNA. Its occurrence has been reported so far in eight different cyanobacteria species and in several water samples from four of the five continents. With a guideline value of 1 µg l(-1), CYN is now considered the second most studied cyanotoxin worldwide. It is important to review the information regarding the findings made until now about this cyanotoxin 30 years since its first report.

Emergent marine toxins risk assessment using molecular and chemical approaches.

Cyanobacteria harmful blooms represent a deviation to the normal equilibrium in planktonic communities involving a rapid and uncontrolled growth. Owing to the capacity to produce toxins as secondary metabolites, cyanobacteria may cause huge economic losses in the fishing and aquaculture industries and poisoning incidents to humans due to their accumulation in the food chain. The conditions which promote toxic blooms have not yet been fully understood, but climate change and anthropogenic intervention are pointed as significant factors. For the detection of toxins in edible marine organisms, the establishment of international regulations and compulsory surveillance has been probed as exceptionally effective. However, not regulation nor monitoring have been settled concerning emergent marine toxins. In the light of this scenario, it becomes essential to apply fast and reliable surveillance methodologies for the early detection of cyanobacterial blooms as well as the occurrence of emergent marine toxins. Shotgun metagenomic sequencing has potential to become a powerful diagnostic tool in the fields of food safety and One Health surveillance. This culture-independent approach overcomes limitations of traditional microbiological techniques; it allows a quick and accurate assessment of a complex microbial community, including quantitative identification and functional characterisation, in a single experiment. In the framework of the EU-FORA fellowship, with the final goal of evaluate metagenomics as a promising risk assessment tool, the fellow worked on the development of an innovative workflow through state-of-the-art molecular and chemical analytical procedures. This work programme aims to evaluate the occurrence of emergent marine toxins and the producing organisms in Cabo Verde coastal cyanobacteria blooms. Our results show the outstanding potential of a holistic metagenomic approach for the risk assessment of emergent marine toxins and the producing organisms. Additionally, we have also highlighted its value for the identification and evaluation of secondary metabolites as natural bioactive compounds with biotechnological and industrial interest.

Effects of the microcystin profile of a cyanobacterial bloom on growth and toxin accumulation in common carp Cyprinus carpio larvae.

A 12 day growth trial was conducted to compare the effect of the variation in microcystins (MC) composition of two bloom samples of Microcystis aeruginosa on the growth performance and microcystin accumulation in common carp Cyprinus carpio larvae. Two M. aeruginosa natural bloom samples with different MC profiles were collected and larvae were exposed to cyanobacterial cells through their diet. Three diets, a basal control diet and two diets prepared from the basal diet plus the same toxins content (60 ng MC g(-1) diet) of each cyanobacterial bloom, were given at the same ration level to three groups of larvae during the experimental period. Larval mass and standard length from day 9 were significantly different between cyanobacterial treatments and in both cases lower than that of the control. The MC accumulation by larvae, inversely correlated with the growth performance, was also significantly different between cyanobacterial treatments (26.96 v. 17.32 ng g(-1) at the end of the experimental period). These results indicate that MC variants profile may have effects on the toxin uptake and toxicity. To date, this is the first laboratory study to show that fish accumulate MC depending on the toxin profile of the cyanobacterial bloom.

Sinonasal melanoma: a systematic review of the prognostic factors.

The objective was to evaluate the available published data on sinonasal melanoma and analyse its clinical features, treatment modalities, and prognostic factors. An electronic search was undertaken in March 2018 in multiple databases. Eligibility criteria included publications with sufficient clinical, histological, and immunohistochemical information to confirm the diagnosis. Seventy-three publications (439 cases) were included. The lesion was more prevalent in females than in males. There was a higher prevalence in the seventh and eighth decades of life. The lesions mainly presented as epistaxis and commonly involved the nasal cavity. Age (>67.6 years; P=0.0012), primary location (middle turbinate; P=0.0112), disease stage (advanced disease stage; P=0.0026), treatment (radiotherapy; P=0.0111), recurrence (recurrence presented; P=0.0137), and distant metastasis (distant metastasis presented; P=0.0011) were independently associated with a lower survival rate. Recurrence was significantly correlated with age (>67.6 years; P=0.0021), sex (males tended to present a higher recurrence rate than females; P=0.0051), disease stage (stages III and IV presented a higher recurrence rate than stages I and II; P=0.0331), and histological type (amelanotic lesions presented a higher index of recurrence than melanotic lesions; P=0.0095). In conclusion, sinonasal melanoma is a neoplasm with a poor prognosis, presenting a 30.69% possibility of survival after 5 years.

Detection of microcystin contamination by the measurement of the variability of the in vivo chlorophyll fluorescence in aquatic plant Lemna gibba.

In recent years, chlorophyll fluorescence analysis has become one of the most powerful and widely used techniques available to plant ecophysiologists. In this work, the chlorophyll fluorescence is used in order to evaluate the biotic stress induced by exposure to cyanobacterial toxins (microcystins). Experiments were carried on the aquatic plant Lemna gibba exposed to various concentrations of a microcystins (0.01, 0.03, 0.05, 0.07, 0.15, 0.22 and 0.3mug equivalent MC-LR.mL(-1)) during 5h. The reversibility of the stress changes was also studied following 24h of treatment. The efficiency and the utility of this biophysical technique were compared to biochemical analysis priory used to evaluate the plant stress induced by such contamination. The results showed that there is a concentration-dependent effect on the measured in vivo chlorophyll fluorescence with significant differences between the control and all concentrations except for 0.01mug equivalent MC-LR.mL(-1). The reversibility tested showed also that after avoiding the contact with the microcystins, the chlorophyll fluorescence measurements were not significantly different from the control. The results showed that if the contact with the microcystins is short and not repeated plants may not suffer from a significant stress. We concluded that this simple and rapid technique based on the variable fluorescence, could be recommended and applied to test the plant stress caused by cyanobacterial toxins.

Evaluation of the efficacy of strains of Steinernema carpocapsae Santa Rosa and ALL (Steinernematidae: Rhabditida) to control engorged female Anocentor nitens (Acari: Ixodidae).

In view of the need to combat the generalized spread of resistance in ticks to commercial acaricides, the objective of this study was to evaluate the action of entomopathogenic nematodes (Steinernema carpocapsae, strains Santa Rosa and ALL) on engorged female Anocentor nitens. Five ticks per Petri dish were exposed to concentrations of 500, 5,000, or 25,000 infective juveniles of S. carpocapsae for 72 h. After transferring the ticks to clean plates, biological parameters were analyzed. Related to strains Santa Rosa, the period of pre-oviposition (p = 0.0001), oviposition (p = 0.041), and the mass weight of eggs (p = 0.005) showed significant differences between the control group and treated group. When the strain ALL was tested, the control and treated groups differed between the periods of pre-oviposition (p = 0.001), oviposition (p = 0.001), and egg mass weight (p = 0.01). The egg mass conversion was less significant in the groups when exposed to strains Santa Rosa (p = 0.002) and ALL (p = 0.001) relative to the control. The efficacy of both entomopathogenic nematode strains used in this study was comparable to other biological control agents, showing their potential against A. nitens in the laboratory.

Effects of cyanobacterial extracts containing anatoxin-a and of pure anatoxin-a on early developmental stages of carp.

This study compares the effects of pure anatoxin-a and cyanobacterial extracts of an anatoxin-a producing strain on early stages of development of carp. Carp eggs were exposed from 2:30 h to 4 days post-fertilization to different ecologically relevant concentrations of anatoxin-a, provided as pure toxin or contained in the cyanobacterial extracts. Data on time to mortality, mortality rate, time to hatching, hatching rate, skeletal malformations rate, and larval standard length were registered until 8 days post-fertilization. At any tested concentration of anatoxin-a, the pure toxin was almost harmless to carp early stages of development, contrarily to cell extracts that were highly toxic. Only an adverse effect on the larval length was found at the highest concentration of pure toxin, while increasing concentrations of cell extracts caused increasing adverse effects in all the analyzed parameters. Anatoxin-a producing cyanobacteria should be regarded as putative modulators of aquatic ecosystems communities.

Identification and quantification of microcystins from a Nostoc muscorum bloom occurring in Oukaïmeden River (High-Atlas mountains of Marrakech, Morocco).

Health risks generated by cyanobacterial toxins in drinking and recreational waters are clearly recognised. During the monitoring programme on the distribution of toxic freshwater cyanobacteria in various water bodies including reservoirs, ponds and rivers of Morocco, many toxigenic cyanobacteria bloom-forming species have been identified. Particular attention was given to the investigation of the toxicology of a benthic Nostoc species-Nostoc muscorum Ag. (cyanobacteria, Nostocales, Nostocaceae)-that was found dominant in Oukaïmeden river located at 2,600 m of altitude in High-Atlas mountains of Marrakech. The massive growth of the mat-forming N. muscorum occurred yearly during the period of March-October, when the water temperature was above 10 degrees C. During 1997-1999, samples were collected from either floating or benthic mats. Hepatotoxicity associated to gastrointestinal (diarrhoea) intoxication symptoms was confirmed by intraperitoneal (i.p.) injection in mice of N. muscorum thallus extract. The survival time was estimated to be from 2-5 h, and the calculated i.p. LD(50) in mice ranged from 15 to 125 mg kg(-1) body weight. The application of the high performance liquid chromatography with photodiode array detection confirmed the occurrence of microcystin-LR (MC-LR) and three others microcystin variants from the methanolic Nostoc extract. The MC-LR represented a proportion of 39% of the total microcystin content however, the total concentration equivalents-eq-of MC-LR was estimated to be 139 microg MC-LR eq per gram dry weight. The existence of a benthic microcystin-producing N. muscorum strain under the particular environmental conditions of Oukaïmeden region may be a potential human health hazard and the ecological harmful effects of these cyanobacterial toxins need to be assessed. This paper constitutes the first report of the occurrence of a toxic benthic Nostoc in Morocco. So, the benthic species should be considered during monitoring of toxic Cyanobacteria particularly for river used for source of drinking water.

Patient preferences for attributes of topical anti-psoriatic medicines.

Background: Patient preferences should be considered when prescribing topical treatments to drive up adherence and improve clinical outcomes. Objective: The aim of this work was to identify the most important attributes of topical medicines for psoriasis treatment in the patients' view, and explore the sociodemographic and clinical determinants of these preferences. Methods: A questionnaire for the evaluation of the relevancy given to specific attributes of topical medicines used for psoriasis treatment was developed (PSO-TOPAP) and was applied to a total of seventy-nine patients, members of the Portuguese Association of Psoriasis (PSOPortugal) or outpatients of a dermatology unit of a central hospital. Results: Overall, attributes belonging to the formulation and application domains were greatly valued over attributes related to the container. Only a small number of patient preferences was influenced by age, gender, duration of the disease and age at first diagnosis. Limitations: Our findings need to be verified in larger and more diverse patient samples before generalization can be made. Conclusion: The insight obtained in this work can provide guidance to pharmaceutical drug product design and has also the potential to improve patient care through the acknowledgment of patient preferences in clinical practice.

Chondrosarcoma of the jaw bones: a review of 224 cases reported to date and an analysis of prognostic factors.

The objective was to integrate the available published data on chondrosarcoma (CHS) of the jaw bones into a comprehensive analysis of its clinical and histological features, treatment, and prognostic factors. An electronic search was undertaken in October 2017. To be eligible, the publication had to provide sufficient clinical/histological data to confirm the diagnosis. One hundred and ten publications (224 cases of CHS) were identified and included. There was a slightly higher prevalence of CHS in males than in females. Most subjects with CHS were in the second to fifth decades of life. The most common symptom was swelling and the most commonly observed location was the maxilla. Histologically, most tumours were of the conventional type and were low grade tumours. The treatment of choice was tumour resection. Histological grade, treatment with chemotherapy alone, and the presentation of recurrence or metastasis were found to be significant independent prognostic factors: patients who presented high-grade tumours, who received chemotherapy alone as the treatment of choice, and those who presented recurrence or metastasis were more likely to have a worse prognosis. In addition, radical surgery associated with radiotherapy as the treatment protocol showed a better prognosis.

Antimicrobial and cytotoxic assessment of marine cyanobacteria - Synechocystis and Synechococcus.

Aqueous extracts and organic solvent extracts of isolated marine cyanobacteria strains were tested for antimicrobial activity against a fungus, Gram-positive and Gram-negative bacteria and for cytotoxic activity against primary rat hepatocytes and HL-60 cells. Antimicrobial activity was based on the agar diffusion assay. Cytotoxic activity was measured by apoptotic cell death scored by cell surface evaluation and nuclear morphology. A high percentage of apoptotic cells were observed for HL-60 cells when treated with cyanobacterial organic extracts. Slight apoptotic effects were observed in primary rat hepatocytes when exposed to aqueous cyanobacterial extracts. Nine cyanobacteria strains were found to have antibiotic activity against two Gram-positive bacteria, Clavibacter michiganensis subsp. insidiosum and Cellulomonas uda. No inhibitory effects were found against the fungus Candida albicans and Gram-negative bacteria. Marine Synechocystis and Synechococcus extracts induce apoptosis in eukaryotic cells and cause inhibition of Gram-positive bacteria. The different activity in different extracts suggests different compounds with different polarities.

Potential of synthetic chalcone derivatives to prevent marine biofouling.

Biofouling represents a major economic, environmental and health concern for which new eco-friendly solutions are needed. International legislation has restricted the use of biocidal-based antifouling coatings, and increasing efforts have been applied in the search for environmentally friendly antifouling agents. This research work deals with the assessment of the interest of a series of synthetic chalcone derivatives for antifouling applications. Sixteen chalcone derivatives were synthesized with moderate yields (38-85%). Antifouling bioactivity of these compounds was assessed at different levels of biological organization using both anti-macrofouling and anti-microfouling bioassays, namely an anti-settlement assay using mussel (Mytilus galloprovincialis) larvae, as well as marine bacteria and microalgal biofilms growth inhibition bioassays. Results showed that three compounds (11, 12, and 16) were particularly active against the settlement of mussel larvae (EC50 7.24-34.63 µM), being compounds 12 and 16 also able to inhibit the growth of microfouling species (EC50 4.09-20.31 µM). Moreover, the most potent compounds 12 and 16 were found to be non-toxic to the non-target species Artemia salina (<10% mortality at 25 µM). A quantitative structure-activity relationship model predicted that descriptors describing the ability of molecules to form hydrogen bonds and encoding the shape, branching ratio and constitutional diversity of the molecule were implied in the antifouling activity against the settlement of mussel larvae. This work elucidates for the first time the relevance of synthesizing chalcone derivatives to generate new non-toxic products to prevent marine biofouling.

Dynamics of glutathione-S-transferases in Mytilus galloprovincialis exposed to toxic Microcystis aeruginosa cells, extracts and pure toxins.

Molluscs and especially bivalves are able to accumulate dinoflagelates, diatoms and cyanobacteria toxins, and, being vectors for these toxins, transfer them along food chains. The data obtained from laboratory experiments showed that bivalve molluscs are resistant to cyanobacteria toxins. In this work, we wanted to test if Mytilus galloprovincialis organs react to microcystins and other cyanobacteria compounds by inducing or decreasing its GST activity. Acclimated mussels M. galloprovincialis were exposed to the toxic Microcystis aeruginosa M13 strain. Exposure of mussels to toxins was done in three ways: living Microcystis cells, crude Microcystis extracts and pure toxins. The measurement of soluble and microsomal GST activity in the different mussel organs was done by using the substrates 1-chloro-2,4-dinitrobenzene (CDNB) and 2,4-dichloro-1-nitrobenzene (DCNB). Analysis of the GST activity of the control mussels using CDNB as a substrate showed that cytosolic activity is much more significant than microsomal. Intact M. aeruginosa cells did not induce any significant response from the mussels, showing that these animals are quite resistant to the cyanobacteria if they are intact. On the other hand, cell extracts caused an important effect in the gut, in the gills and in the labial palps, although in different ways. There was an increase in GST activity in the gut and gills of mussels exposed to Microcystis extracts, showing a response of this detoxication pathway, but in the labial palps a severe reduction in GST activity occurred. Pure MC LR+YR induced an increase in GST activity in all organs but the labial palps. The results showed that other substances apart from microcystins may cause stress to mussels and affect detoxication enzymes such as GST.