European Red List of Marine Fishes

The European Red List is a review of the conservation status of European species according to IUCN regional Red Listing guidelines. It identifies those species that are threatened with extinction at the regional level, so that appropriate conservation action can be taken to improve their status. This Red List publication summarises results for all described native European marine fishes.Postprin

Dealing with Food and Eggs in Mouthbrooding Cichlids: Structural and Functional Trade-Offs in Fitness Related Traits

As in any vertebrate, heads of fishes are densely packed with functions. These functions often impose conflicting mechanical demands resulting in trade-offs in the species-specific phenotype. When phenotypical traits are linked to gender-specific parental behavior, we expect sexual differences in these trade-offs. This study aims to use mouthbrooding cichlids as an example to test hypotheses on evolutionary trade-offs between intricately linked traits that affect different aspects of fitness. We focused on the oral apparatus, which is not only equipped with features used to feed and breathe, but is also used for the incubation of eggs. We used this approach to study mouthbrooding as part of an integrated functional system with diverging performance requirements and to explore gender-specific selective environments within a species.Because cichlids are morphologically very diverse, we hypothesize that the implications of the added constraint of mouthbrooding will primarily depend on the dominant mode of feeding of the studied species. To test this, we compared the trade-off for two maternal mouthbrooding cichlid species: a "suction feeder" (Haplochromis piceatus) and a "biter" (H. fischeri). The comparison of morphology and performance of both species revealed clear interspecific and intersex differences. Our observation that females have larger heads was interpreted as a possible consequence of the fact that in both the studied species mouthbrooding is done by females only. As hypothesized, the observed sexual dimorphism in head shape is inferred as being suboptimal for some aspects of the feeding performance in each of the studied species. Our comparison also demonstrated that the suction feeding species had smaller egg clutches and more elongated eggs.Our findings support the hypothesis that there is a trade-off between mouthbrooding and feeding performance in the two studied haplochromine cichlids, stressing the importance of including species-specific information at the gender level when addressing interspecific functional/morphological differences

Sulfur as pollutant species on the cathode side of a SOFC system

Sulfur poisoning in a strontium doped lanthanum cobaltite (LSC) cathode current collection layer was revealed in a solid oxide fuel cell (SOFC) tested in repeat-element and stack configuration. Sources of sulfur contamination, other than trace SOx in air, were identified. Strontium sulfate (SrSO4) and strontium chromate (SrCrO4) enriched with sulfur were found at the interface between LSC and air channels. Understanding degradation mechanisms is a major issue in the development of SOFCs. In particular, in repeat-element and stack configuration, an important coupling of different degradation processes exists, with internal sources at the stack level and exogenous sources coming from system components. A specific diagnostic test station was developed to allow locally-resolved measurements of electrochemical performance and degradation in a repeat-element. Large differences in local degradation behavior were observed, affecting different electrochemical processes. Post-mortem analysis, mainly done by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX), allowed to identify the pollutant species responsible for degradation. Complete results are published elsewhere [1-2]. In this study, an anode-supported cell, with an active strontium doped lanthanum manganite (LSM) - yttria stabilized zirconia (YSZ) composite cathode and a LSC current collection layer, was tested over 1900 h around 1073 K. Chromium and sulfur were found as major pollutant species on the cathode side; both are dependent on upstream conditions and components. While chromium poisoning is well known for SOFC cathodes, sulfur contamination of the cathode has received more attention recently. Sulfur poisoning is a major limitation for wide use of perovskite catalysts for treatment of auto exhaust gas [3]. Sulfur pollution from trace SOx in air and involving sulfate formation was reported by Xu et al. [4], where perovskite-type ceramics were used for oxygen permeation membranes. Yokokawa et al. identified sulfur as impurity after long-term operation of SOFC stacks in [5], and Xiong et al. reported and studied sulfur poisoning of different cathode materials just recently [6]. In the present experiment, a commercial vulcanized polymer tube for air inlet and an insulating high temperature sealing paste were identified as potential sulfur sources. Figure 1 shows the LSC microstructure before and after exposure to sulfur containing air. Strontium sulfate growth on porous LSC surface leads to an almost dense sulfate layer. Strontium sulfate was found over the whole LSC thickness without affecting the LSM/YSZ cathode. The more pronounced strontium sulfate formation in LSC compared to LSM is explained by the higher activity of strontium oxide (SrO) in LSC [7]. Chromium on the LSC surface was only found at the air-inlet, indicating that Cr was principally evaporated from upstream system components. SEM/EDX analysis allowed to identify sulfur-rich strontium chromate with a composition close to Sr(Cr0.85S0.15)O4. The chromate structure is changing along the airflow direction, from an almost dense structure to isolated particles, while maintaining the same composition. Further analyses are ongoing to confirm sulfate and chromate crystalline structures

A naturally occurring mutation K220T in the pleiotropic activator PrfA of Listeria monocytogenes results in a loss of virulence due to decreasing DNA-binding affinity

International audienceThe sequencing of prfA, encoding the transcriptional regulator of virulence genes, in 26 low virulence field Listeria monocytogenes strains showed that eight strains exhibited the same single amino-acid substitution: PrfAK220T. These strains exhibited no expression of PrfA-regulated proteins and thus no virulence. This substitution inactivated PrfA, since expression of the PrfAK220T mutant gene in an EGDΔprfA strain did not restore the haemolytic and phosphatidylcholine phospholipase C activities, in contrast to the wild-type prfA gene. The substitution of the lysine at position 220 occurred in the helix αH. However, the data showed that the PrfAK220T protein is dimerized just as well as its wild-type counterpart, but does not bind to PrfA boxes. PrfAK220T did not form a PrfA–DNA complex in electrophoretic mobility shift assays, but low concentrations of CI complexes (PrfAK220T–RNA polymerase–DNA complex) were formed by adding RNA polymerase, suggesting that PrfA interacted with RNA polymerase in solution in the absence of DNA. Formation of some transcriptionally active complexes was confirmed by in vitro runoff transcription assays and quantitative RT-PCR. Crystallographic analyses described the structure of native PrfA and highlighted the key role of allosteric changes in the activity of PrfA and especially the role of the Lys220 in the conformation of the helix–turn–helix (HTH) motif