Departamento de Biologia

In order for natural selection to operate, physiological and behavioural traits must exhibit both inter-individual variability and intra-individual consistency (i.e. repeatability) in performance. In this study, we describe individual variation and temporal repeatability in the escape responses of the queen scallop, Aequipecten opercularis, and determine whether individuals exhibited consistently high or low rankings in different aspects of the escape response. Five measures of individual performance were recorded on four occasions (days 0, 2, 7 and 28), providing proxies for sensory acuity (response latency), immediate and sustained swimming performance (burst and average clap rates), and swimming endurance (total number of claps and total time spent clapping). All components of the escape response exhibited significant inter-individual variability (all P<0.0001). Escape response latency, burst clap rate, total number of claps and total duration spent clapping maintained significant repeatability over 28. days (all P<0.016). Average clap rate was repeatable in the short term (2. days, P<0.0001) but repeatability declined by 28. days (P=0.097). Concordance analysis indicated that individuals maintained the same performance rankings over time for each component of the escape response (all P<0.001). In addition, some individuals ranked as consistently high or low performers across response latency, burst and average clap rate, and total number of claps. An individual's ability to evade predators through the provision of an escape response of an appropriate magnitude, subject to physiological, behavioural and organismal constraints, will have clear fitness-related consequences.

Mussels within the subfamily Bathymodiolinae, in particular the larger Bathymodiolus species (sensu lato) thriving at cold seeps and hydrothermal vents, are among the most iconic fauna to colonize deep-sea reducing habitats globally. Fuelled by energy derived from chemosynthetic symbioses, their contribution to ecosystem productivity is conspicuous, with many bathymodioline species forming dense, extensive aggregates. Chemosymbiotic mussels play crucial roles as ecosystem engineers, both through the formation of spatially heterogeneous biogenic reefs and in redistributing reduced-fluid emissions. The notable absence of Bathymodiolinae outside of reducing ecosystems affirms their dependency on these ephemeral habitats, placing spatiotemporal constraints on dispersal to, and colonization of nascent, chemosynthetically active substrata. Thus, although symbioses may explain why these mussels are so productive in deep-sea reducing habitats, species' survival over successive generations depends largely upon the adaptive characteristics of their lifecycle as a whole. Despite accumulating data on the biology and ecology of adults however, details remain fragmented regarding earlier developmental junctures during their development. This paper therefore brings together results from research undertaken over recent years on this topic, providing a synthesis of various lifecycle aspects of bathymodiolins from the earliest stages of development, gametogenesis, through to sexual maturity, including the intrinsic, emerging role of symbionts. The review provides a comprehensive overview of our current understanding and identifies areas where further study into these keystone organisms is warranted. The benefits of applying an integrated, lifecycle approach when evaluating the potential impacts of global change and anthropogenic activities upon deep-sea fauna and their habitats are then discussed.

Idas argenteus (Bivalvia: Mytilidae) belongs to a genus of mussels that are often associated with sunken wood and vertebrate bones in the deep sea. By contrast to other species currently included within the genus Idas and other related genera, such as Bathymodiolus, I.argenteus was documented to lack chemosynthetic symbionts bacterial symbionts in its gills. In the present study, new specimens are assigned to I.argenteus based on shell and soft parts analysis. Molecular data confirm the absence or low abundance of symbionts. Phylogeny based on five genes indicates that the symbiont-bearing I.washingtonius is the closest relative of I.argenteus. Symbiosis loss or extreme reduction is thus inferred to have occurred subsequent to the speciation event, 11-13Mya. This is the first report of a loss of symbiosis within the clade of deep-sea chemosynthetic mussels.

Bacterial symbionts associated with animal tissues play major roles in the functioning of various ecosystems. Identification of bacteria often relies on marker gene comparative sequence analysis and fluorescence in situ hybridization (FISH). However, analysis of bacteria and host ultrastructure using transmission electron microscopy (TEM) can be equally important to understand the localization of bacteria and the degree of host-symbiont integration. We here provide a protocol which allows both FISH and TEM to be performed sequentially on a single section of tissue. Observations can then be superimposed, allowing ultrastructural investigation to be coupled with proper FISH-based identification of bacteria.

The aim of this study was to determine the effect of some pre-harvest fungicides on growth and aflatoxin (AF) production of three Aspergillus flavus strains found in Capsicum powder. Each isolate, previously isolated from paprika, chilli and smoked paprika, was inoculated on yeast extract sucrose agar and on a 3% paprika extract agar medium supplemented with different fungicides and incubated at 20 and 30°C during 7 days. Growth measurements were obtained on days 3, 5 and 7, and the AF production was determined on day 7. The significance of the effects of the factors (strain, medium, temperature, time and fungicides) and their interaction over colony diameter and AF production was determined. Temperature constrained the effectiveness of fungicides in reducing growth, the fungicides being most effective at 20°C. The efficacy of the fungicides over AF production depended on the medium used and temperature. The most effective fungicides in inhibiting growth and AF production, regardless of the strain tested or applied conditions, were tebuconazole 25% and mancozeb 80% applied at a concentration of 0.75 and 3.5 g l−1, respectively. Care should thus be taken in the choice of a suitable fungicide because their effectiveness may depend on intra-specific variation and temperature. Moreover, it is necessary to take into account that the most efficient fungicide in reducing growth is not always the best choice for pre-harvest treatments because it may promote AF production. Thus, the best fungicide is the one that can simultaneous prevent growth and AF production.

BACKGROUND: The aim of this study was to screen the multicontamination by mycotoxins in a wide variety of aromatic and/or medicinal herb samples collected in Spain. Mycotoxins studied were aflatoxins (AFs), ochratoxin A (OTA), zearalenone (ZEA), deoxynivalenol (DON), T-2 toxin (T-2), citrinin and fumonisins (FBs). Mycotoxins were analysed by ELISA after a clean-up step with multifunctional columns (AFs, ZEA, DON, FBs and T-2) or polyamide column (citrinin).RESULTS: Of the 84 samples analysed 99% were contaminated with T-2, 98% with ZEA, 96% with AFs, 63% with OTA, 62% with DON, 61% with citrinin and 13% with FBs. Nearly 87% of samples contained four or more mycotoxins simultaneously, being AFs, T-2 and ZEA the mycotoxins co-existing in almost every sample. 100% of the samples in our study were multicontaminated.CONCLUSION: This study shows that this kind of commodity could be an important source of mycotoxin contamination and, in general, this contamination is not limited to only one group of mycotoxins. Mycotoxin contamination on artichoke immature florets, boldus leaves, burdock leaves, dandelion plant, frangula bark, ginkgo leaves, lemon verbena leaves, olive leaves, red tea leaves, ribgrass leaves, St Mary's thistle seeds, spearmint leaves, star anise fruit, vervain and white tea leaves has been described for the first time. Finally, this is the first report on DON and T-2 presence in herbs. No study of this kind has been previously developed in Spain. Copyright © 2009 Society of Chemical Industry

... et al., 1993), Morocco (Zinedine et al., 2006), Pakistan (Shamsuddin et al., 1995), Portugal (Martins et al., 2001), Russia (Goryacheva et al., 2006), Singapore (Scott and Kennedy, 1973), the Netherlands (Goryacheva et al., 2006), Turkey (Erdogan, 2004; Bircan, 2005; Colak et al ...

Background. Species identification is essential for controlling disease, understanding epidemiology, and to guide the implementation of phytosanitary measures against fungi from the genus Diaporthe. Accurate Diaporthe species separation requires using multi-loci phylogenies. However, defining the optimal set of loci that can be used for species identification is still an open problem. Methods. Here we addressed that problem by identifying five loci that have been sequenced in 142 Diaporthe isolates representing 96 species: TEF1, TUB, CAL, HIS and ITS. We then used every possible combination of those loci to build, analyse, and compare phylogenetic trees. Results. As expected, species separation is better when all five loci are simultaneously used to build the phylogeny of the isolates. However, removing the ITS locus has little effect on reconstructed phylogenies, identifying the TEF1-TUB-CAL-HIS 4-loci tree as almost equivalent to the 5-loci tree. We further identify the best 3-loci, 2-loci, and 1-locus trees that should be used for species separation in the genus. Discussion. Our results question the current use of the ITS locus for DNA barcoding in the genus Diaporthe and suggest that TEF1 might be a better choice if one locus barcoding needs to be done.

ABSTRACT The present study aimed to assess the effect of some pre-harvest fungicides commonly used in Capsicum fruit production on growth and ochratoxin A production of three Aspergillus species found in Capsicum powder. Aspergillus tubingensis, Aspergillus ochraceus and Aspergillus westerdijkiae, previously isolated from paprika and chilli, were inoculated on yeast extract sucrose agar and paprika extract agar supplemented with different fungicides at their recommended dosage rates, and incubated at 20 and 30 degrees C during 7 days. Radial growth was measured after 3, 5 and 7 days and ochratoxin A production was determined by high-performance liquid chromatography with fluorescence detection on day 7. Dodine 40% and mancozeb 80% were the most effective fungicides in inhibiting growth and ochratoxin A production, regardless of the fungal strain tested or temperature conditions. Whereas the application of fungicides could be very attractive in reducing the mycotoxigenic fungal load, it can also stimulate ochratoxin A production in some cases.