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Funder: Sigrid Juséliuksen Säätiö; doi: http://dx.doi.org/10.13039/501100006306, Cichlid fishes are a very diverse and species-rich family of teleost fishes that inhabit lakes and rivers of India, Africa, and South and Central America. Research has largely focused on East African cichlids of the Rift Lakes Tanganyika, Malawi, and Victoria that constitute the biodiversity hotspots of cichlid fishes. Here, we give an overview of the study system, research questions, and methodologies. Research on cichlid fishes spans many disciplines including ecology, evolution, physiology, genetics, development, and behavioral biology. In this review, we focus on a range of organismal traits, including coloration phenotypes, trophic adaptations, appendages like fins and scales, sensory systems, sex, brains, and behaviors. Moreover, we discuss studies on cichlid phylogenies, plasticity, and general evolutionary patterns, ranging from convergence to speciation rates and the proximate and ultimate mechanisms underlying these processes. From a methodological viewpoint, the last decade has brought great advances in cichlid fish research, particularly through the advent of affordable deep sequencing and advances in genetic manipulations. The ability to integrate across traits and research disciplines, ranging from developmental biology to ecology and evolution, makes cichlid fishes a fascinating research system.

The use of zebrafish (Danio rerio) has arisen as a promising biological platform for toxicity testing of pesticides such as herbicides, insecticides, and fungicides. Therefore, it is relevant to assess the use of zebrafish in models of exposure to investigate the diversity of pesticide-associated toxicity endpoints which have been reported. Thus, this review aimed to assess the recent literature on the use of zebrafish in pesticide toxicity studies to capture data on the types of pesticide used, classes of pesticides, and zebrafish life stages associated with toxicity endpoints and phenotypic observations. A total of 352 articles published between September 2012 and May 2019 were curated. The results show an increased trend in the use of zebrafish for testing the toxicity of pesticides, with a great diversity of pesticides (203) and chemical classes (58) with different applications (41) being used. Furthermore, experimental outcomes could be clustered in 13 toxicity endpoints, mainly developmental toxicity, oxidative stress, and neurotoxicity. Organophosphorus, pyrethroid, azole, and triazine were the most studied classes of pesticides and associated with various toxicity endpoints. Studies frequently opted for early life stages (embryos and larvae). Although there is an evident lack of standardization of nomenclatures and phenotypic alterations, the information gathered here highlights associations between (classes of) pesticides and endpoints, which can be used to relate mechanisms of action specific to certain classes of chemicals.

The use of zebrafish (Danio rerio) has arisen as a promising biological platform for toxicity testing of pesticides such as herbicides, insecticides, and fungicides. Therefore, it is relevant to assess the use of zebrafish in models of exposure to investigate the diversity of pesticide-associated toxicity endpoints which have been reported. Thus, this review aimed to assess the recent literature on the use of zebrafish in pesticide toxicity studies to capture data on the types of pesticide used, classes of pesticides, and zebrafish life stages associated with toxicity endpoints and phenotypic observations. A total of 352 articles published between September 2012 and May 2019 were curated. The results show an increased trend in the use of zebrafish for testing the toxicity of pesticides, with a great diversity of pesticides (203) and chemical classes (58) with different applications (41) being used. Furthermore, experimental outcomes could be clustered in 13 toxicity endpoints, mainly developmental toxicity, oxidative stress, and neurotoxicity. Organophosphorus, pyrethroid, azole, and triazine were the most studied classes of pesticides and associated with various toxicity endpoints. Studies frequently opted for early life stages (embryos and larvae). Although there is an evident lack of standardization of nomenclatures and phenotypic alterations, the information gathered here highlights associations between (classes of) pesticides and endpoints, which can be used to relate mechanisms of action specific to certain classes of chemicals.

It is fascinating that the amnion and serosa/chorion, two extraembryonic (EE) tissues that are characteristic of the amniote vertebrates (mammals, birds and reptiles), have also independently evolved in insects. In this review, we offer the first detailed, macroevolutionary comparison of EE development and tissue biology across these animal groups. Some commonalities represent independent solutions to shared challenges for protecting the embryo (environmental assaults, risk of pathogens) and supporting its development, including clear links between cellular properties (e.g. polyploidy) and physiological function. Further parallels encompass developmental features such as the early segregation of the serosa/chorion compared to later, progressive differentiation of the amnion and formation of the amniotic cavity from serosal–amniotic folds as a widespread morphogenetic mode across species. We also discuss common developmental roles for orthologous transcription factors and BMP signalling in EE tissues of amniotes and insects, and between EE and cardiac tissues, supported by our exploration of new resources for global and tissue-specific gene expression. This highlights the degree to which general developmental principles and protective tissue features can be deduced from each of these animal groups, emphasizing the value of broad comparative studies to reveal subtle developmental strategies and answer questions that are common across species. This article is part of the theme issue ‘Extraembryonic tissues: exploring concepts, definitions and functions across the animal kingdom’.

Octopuses have evolved incredibly large and complex nervous systems that allow them to perform impressive behaviors, like plan ahead, navigate and solve puzzles. The nervous system of the common octopus (also known as Octopus vulgaris) contains over half a billion nerves cells called neurons, similar to the number found in small primates. Two thirds of these cells reside in the octopuses’ arms, while the rest make-up a central brain that sits between their eyes. Very little is known about how this central brain forms in the embryo, including where the cells originate and which molecular factors drive their maturation in to adult cells. To help answer these questions, Deryckere et al. studied the brain of Octopus vulgaris at different stages of early development using various cell staining and imaging techniques. The experiments identified an important pool of dividing cells which sit in an area outside the central brain called the ‘lateral lips’. In these cells, genes known to play a role in neural development in other animals are active, indicating that the cells had not reached their final, mature state. In contrast, the central brain did not seem to contain any of these immature cells at the point when it was growing the most. To investigate this further, Deryckere et al. used fluorescent markers to track the progeny of the dividing cells during development. This revealed that cells in the lateral lips take on a specific neuronal fate before migrating to their target region in the central brain. Newly matured neurons have also been shown to travel large distances in the embryos of vertebrates, suggesting that this mechanism may be a common strategy for building large, complex brains. Although the nervous system of the common octopus is comparable to mammals, they evolved from a very distant branch of the tree of life; indeed, their last common ancestor was a worm-like animal that lived about 600 million years ago. Studying the brain of the common octopus, as done here, could therefore provide new insights into how complex nervous systems, including our own, evolved over time.

The altricial-precocial spectrum describes the degree of morphological maturation of offspring at the moment of hatching. In fishes, precocial species develop all their structures at early stages of embryogenesis and larvae hatch at an advanced stage of development, while altricial species hatch at a less developed stage. The timing of retinal development also varies significantly between precocial and altricial fish species. Thus, retinal development is completed before hatching in precocial species. In contrast, a relatively simple retina is observed in altricial newborns and the acquisition of the adult retinal features extends until late in larval life. Therefore, retinal maturation at hatching could be considered as a morphological character to describe the developmental mode of fish newborns. Syngnathids fishes hatch with well-developed sensory systems, jaws, and feeding structures and, therefore, they are considered as precocial fish species. Using as a model the retina of two species of syngnathids (Syngnathus typhle and Hippocampus guttulatus), we describe the retinal maturity during different embryological stages and compare the results with previous studies in the retina of other altricial and precocial fish species. This will be done through a review of the pertinent literature, as well as by drawing on our own experience gathered through recent studies on fish retinogenesis. These differences in the maturity of the visual system have implications for the vision-based survival skills during the early life stages after hatching and for the overall ecology and fitness of the species. Fundacao para a Ciencia e a Tecnologia, PortugalPortuguese Foundation for Science and Technology [PTDC/MAR/122616/2010] Spanish Ministerio de Ciencia y TecnologiaSpanish Government [BFU2007-67540] Junta de Extremadura [PRI06A195, GR15158]

Recent genome-wide association studies and mouse models have identified LIN28B as a gene affecting several pubertal timing-related traits and vertebrate growth. However, the exact biological mechanisms underlying the associations remain unknown. We have explored the mechanisms linking LIN28B with growth regulation by combining human gene expression data with functional models. Specifically, we show that 1) pubertal timing-associated genetic variation correlates with LIN28B expression in the pituitary and hypothalamus, 2) downregulating lin28b in zebrafish embryos associates with aberrant development of kiss2-neurons, and 3) increasing lin28b expression transiently by synthetic mRNA injections during embryogenesis results in sustained enhancement of zebrafish growth. Unexpectedly, the mRNA injections resulted in advanced sexual maturation of female fish, suggesting that lin28b may influence pubertal timing through multiple developmental mechanisms. Overall, these results provide novel insight into LIN28B function in vertebrate growth regulation, emphasizing the importance of the gene and related genetic pathways for embryonic and juvenile development.

Iodothyronine deiodinases are enzymes capable of activating and inactivating thyroid hormones (THs) and have an important role in regulating TH action in tissues throughout the body. Three types of deiodinases (D1, D2, and D3) were originally defined based on their biochemical characteristics. Cloning of the first complementary DNAs in the 1990s (Dio1 in rat and dio2 and dio3 in frog) allowed to confirm the existence of 3 distinct enzymes. Over the years, increasing genomic information revealed that deiodinases are present in all chordates, vertebrates, and nonvertebrates and that they can even be found in some mollusks and annelids, pointing to an ancient origin. Research in nonmammalian models has substantially broadened our understanding of deiodinases. In relation to their structure, we discovered for instance that biochemical properties such as inhibition by 6-propyl-2-thiouracil, stimulation by dithiothreitol, and temperature optimum are subject to variation. Data from fish, amphibians, and birds were key in shifting our view on the relative importance of activating and inactivating deiodination pathways and in showing the impact of D2 and D3 not only in local but also whole body T3 availability. They also led to the discovery of new local functions such as the acute reciprocal changes in D2 and D3 in hypothalamic tanycytes upon photostimulation, involved in seasonal rhythmicity. With the present possibilities for rapid and precise gene silencing in any species of interest, comparative research will certainly further contribute to a better understanding of the importance of deiodinases for adequate TH action, also in humans. ispartof: ENDOCRINOLOGY vol:162 issue:6 ispartof: location:United States status: published

During oocyte growth, transcription is required to create RNA and protein reserves to achieve maternal competence. During this period, the general transcription factor TATA binding protein (TBP) is replaced by its paralogue, TBPL2 (TBP2 or TRF3), which is essential for RNA polymerase II transcription. We show that in oocytes TBPL2 does not assemble into a canonical TFIID complex. Our transcript analyses demonstrate that TBPL2 mediates transcription of oocyte-expressed genes, including mRNA survey genes, as well as specific endogenous retroviral elements. Transcription start site (TSS) mapping indicates that TBPL2 has a strong preference for TATA-like motif in core promoters driving sharp TSS selection, in contrast with canonical TBP/TFIID-driven TATA-less promoters that have broader TSS architecture. Thus, we show a role for the TBPL2/TFIIA complex in the establishment of the oocyte transcriptome by using a specific TSS recognition code., The vertebrate TATA-binding protein (TBP) paralogue (TBPL2) is only expressed in growing oocytes, where TBP is absent. Here the authors highlight a unique role for the TBPL2/TFIIA complex in the establishment of the oocyte transcriptome by using a specific TSS recognition code.

Current concerns about climate change have led to intensive research attempting to understand how climate-driven stressors affect the performance of organisms, in particular the offspring of many invertebrates and fishes. Although stressors are likely to act on several stages of the life cycle, little is known about their action across life phases, for instance how multiple stressors experienced simultaneously in the maternal environment can modulate the responses to the same stressors operating in the offspring environment. Here, we study how performance of offspring of a marine invertebrate (shore crab Carcinus maenas ) changes in response to two stressors (temperature and salinity) experienced during embryogenesis in brooding mothers from different seasons. On average, offspring responses were antagonistic: high temperature mitigated the negative effects of low salinity on survival. However, the magnitude of the response was modulated by the temperature and salinity conditions experienced by egg-carrying mothers. Performance also varied among cohorts, perhaps reflecting genetic variation, and/or maternal conditions prior to embryogenesis. This study contributes towards the understanding of how anthropogenic modification of the maternal environment drives offspring performance in brooders.

Metabolic diseases such as nonalcoholic fatty liver disease (NAFLD) result from complex interactions between intrinsic and extrinsic factors, including genetics and exposure to obesogenic environments. These risk factors converge in aberrant gene expression patterns in the liver, which are underlined by altered cis-regulatory networks. In homeostasis and in disease states, liver cis-regulatory networks are established by coordinated action of liver-enriched transcription factors (TFs), which define enhancer landscapes, activating broad gene programs with spatiotemporal resolution. Recent advances in DNA sequencing have dramatically expanded our ability to map active transcripts, enhancers and TF cistromes, and to define the 3D chromatin topology that contains these elements. Deployment of these technologies has allowed investigation of the molecular processes that regulate liver development and metabolic homeostasis. Moreover, genomic studies of NAFLD patients and NAFLD models have demonstrated that the liver undergoes pervasive regulatory rewiring in NAFLD, which is reflected by aberrant gene expression profiles. We have therefore achieved an unprecedented level of detail in the understanding of liver cis-regulatory networks, particularly in physiological conditions. Future studies should aim to map active regulatory elements with added levels of resolution, addressing how the chromatin landscapes of different cell lineages contribute to and are altered in NAFLD and NAFLD-associated metabolic states. Such efforts would provide additional clues into the molecular factors that trigger this disease. This article is categorized under: Biological Mechanisms > Metabolism Biological Mechanisms > Regulatory Biology Laboratory Methods and Technologies > Genetic/Genomic Methods.

Tissue factor pathway inhibitor-alpha (TFPI-α) is a Kunitz-type serine protease inhibitor, which suppresses coagulation by inhibiting the tissue factor (TF)/factor VIIa complex as well as factor Xa. In static plasma-phospholipid systems, TFPI-α thus suppresses both factor Xa and thrombin generation. In this article, we used a microfluidics approach to investigate how TFPI-α regulates fibrin clot formation in platelet thrombi at low wall shear rate. We therefore hypothesized that the anticoagulant effect of TFPI-α in plasma is a function of the local procoagulant strength—defined as the magnitude of thrombin generation under flow, due to local activities of TF/factor VIIa and factor Xa. To test this hypothesis, we modulated local coagulation by microspot coating of flow channels with 0 to 100 pM TF/collagen, or by using blood from patients with haemophilia A or B. For blood or plasma from healthy subjects, blocking of TFPI-α enhanced fibrin formation, extending from a platelet thrombus, under flow only at

The present study assessed the influence of sex, size and reproductive status on the meat yield (soft tissues proportion) of the purple dye murex (Bolinus brandaris) from the Ria Formosa lagoon (southern Portugal). During one year of monthly sampling (October 2008 - September 2009), average meat yield of B. brandaris was 40.5±6.1% (range: 25.8-56.1% wet weight), with no significant differences between sexes. Relationships established between specimen size and soft parts weight indicated that both shell length and total weight are excellent indicators of meat yield. Significant differences in meat yield between size classes further reinforced the trend of increasing meat yield during ontogeny. Meat yield exhibited significant monthly variation and a similar temporal trend in both sexes, which were directly related to the reproductive status. Meat yield of B. brandaris was compared with that of other muricid species and the marked influence of the reproductive status on meat yield prompted a comparative assessment of the spawning season and peak of three sympatric muricids (B. brandaris, Hexaplex trunculus and Stramonita haemastoma). Overall, these findings have implications at diverse levels, including the management, regulation and inspection of this fishing/harvesting activity and the commercialization and consumption of this seafood product. El presente estudio evaluó la influencia del sexo, la talla y el estado reproductivo en la proporción de tejidos blandos de la cañaílla (Bolinus brandaris) de la laguna Ria Formosa (sur de Portugal). Durante un año de muestreo mensual (octubre de 2008 - septiembre de 2009), la proporción global de B. brandaris fue de 40.5±6.1% (rango: 25.8- 56.1% peso húmedo), sin diferencias significativas entre sexos. Las relaciones establecidas entre la talla de los ejemplares y el peso de las partes blandas indicaron que tanto la longitud de la concha como el peso total son excelentes indicadores de la proporción de tejidos blandos. Las diferencias significativas entre clases de talla reforzaron aún más la tendencia creciente durante la ontogenia. La proporción de tejidos blandos mostró una variación mensual significativa y una tendencia temporal similar en ambos sexos, que estaban directamente relacionadas con el estado reproductivo. La proporción de tejidos blandos de B. brandaris se comparó con otras especies de murícidos y la marcada influencia del estado reproductivo impulsó una evaluación comparativa de la época y pico de desove de tres murícidos simpátricos (B. brandaris, Hexaplex trunculus y Stramonita haemastoma). En general, estos hallazgos tienen implicaciones a diversos niveles, incluyendo la gestión, regulación e inspección de esta actividad de pesca/marisqueo y la comercialización y consumo de este marisco.

Global warming has substantially changed the environment, but the mechanisms to cope with these changes in animals, including the role of maternal effects, are poorly understood. Maternal effects via hormones deposited in eggs, have important environment-dependent effects on offspring development and fitness: thus females are expected to adjust these hormones to the environment, such as the ambient temperature. Longer-term temperature variation could function as a cue, predicting chick rearing conditions to which yolk hormone levels are adjusted, while short-term temperature variation during egg formation may causally affect hormone transfer to eggs. We studied the effects of ambient temperature on yolk androgens (testosterone and androstenedione) and thyroid hormones (thyroxine and triiodothyronine) in great tits (Parus major) using data from unmanipulated clutches from a wild population and from aviary birds (ad libitum food) exposed to different experimental temperature treatments during five years. Both in the wild and in captivity, longer-term pre-laying ambient temperature was not associated with clutch mean yolk hormone levels, while the way androstenedione and thyroxine levels varied across the laying sequence did associate with pre-laying temperature in the wild. Yolk testosterone levels were positively correlated with short-term temperature (during yolk formation) changes within clutches in both wild and captivity. We also report, for the first time in a wild bird, that yolk thyroxine levels correlated with a key environmental factor: thyroxine levels were negatively correlated with ambient temperature during egg formation. Thus, yolk hormone levels, especially testosterone, seem to be causally affected by ambient temperature. These short-term effects might reflect physiological changes in females with changes in ambient temperature. The adaptive value of the variation with ambient temperatures pre-laying or during egg formation should be studied with hormone manipulations in different thermal environments. (C) 2016 Published by Elsevier Inc.

In this study, we explored the existence of a transcriptional network co-regulated by E2F7 and HIF1 alpha, as we show that expression of E2F7, like HIF1 alpha, is induced in hypoxia, and because of the previously reported ability of E2F7 to interact with HIF1 alpha. Our genome-wide analysis uncovers a transcriptional network that is directly controlled by HIF1 alpha and E2F7, and demonstrates both stimulatory and repressive functions of the HIF1 alpha -E2F7 complex. Among this network we reveal Neuropilin 1 (NRP1) as a HIF1 alpha-E2F7 repressed gene. By performing in vitro and in vivo reporter assays we demonstrate that the HIF1 alpha-E2F7 mediated NRP1 repression depends on a 41 base pairs 'E2F-binding site hub', providing a molecular mechanism for a previously unanticipated role for HIF1 alpha in transcriptional repression. To explore the biological significance of this regulation we performed in situ hybridizations and observed enhanced nrp1a expression in spinal motorneurons (MN) of zebrafish embryos, upon morpholino-inhibition of e2f7/8 or hif1 alpha. Consistent with the chemo-repellent role of nrp1a, morpholino-inhibition of e2f7/8 or hif1 alpha caused MN truncations, which was rescued in TALEN-induced nrp1a(hu10012) mutants, and phenocopied in e2f7/8 mutant zebrafish. Therefore, we conclude that repression of NRP1 by the HIF1 alpha-E2F7 complex regulates MN axon guidance in vivo.

In birds, mothers can affect their offspring's phenotype and thereby survival via egg composition. It is not well known to what extent and time-scales environmental variation in resource availability, either via resource constrains or adaptive adjustment to predicted rearing conditions, influences maternal effects. We experimentally studied whether egg and yolk mass and yolk hormone levels respond to short-term changes in food availability during laying in wild great tits (Parus major). Our treatment groups were: 1) food supplementation (mealworms) from the 1st until the last egg; 2) food supplementation from the 1st first until the 5th egg, where the effect of cessation of the supplementary food treatment could also be studied; 3) no food supplementation (controls). We analysed both nutritional resources (egg, yolk and albumen mass), and the important developmental signals, yolk androgens (testosterone and androstenedione), and for the first time in a wild population, yolk thyroid hormones (thyroxine and 3,5,3’-triiodothyronine). Egg mass is a costly resource for females, androgens most likely non-costly signals, whereas thyroid hormones may be costly signals, requiring environmental iodine. In the food supplemented group egg, yolk and albumen mass increased rapidly relative to controls and when food supplementation was halted, egg and albumen mass decreased, indicating rapid responses to resource availability. Yolk androgen and thyroid hormone levels were not affected by food supplementation during laying. Thyroxine showed an increase over the laying sequence and its biological meaning needs further study. The rapid changes in egg mass to variation in within-clutch food availability suggest energetic/protein/nutrient constrains on egg formation. The lack of a response in yolk hormones suggest that perhaps in this species the short-term changes in resource availability during egg laying do not predict offspring rearing conditions, or (for thyroid hormones) do not cause systemic changes in circulating hormones, and hence do not affect maternal signaling.

This paper describes a novel mass spectrometry based analytical method for analyzing thyroid hormones (THs). Thyroid hormones play a critical role in the regulation of many biological processes such as growth, metabolism and development. Several analytical methods using liquid chromatography-mass spectrometry (LC-MS) and tandem mass spectrometry (LC-MS/MS) have previously been developed to measure THs, especially in humans. For biomedical and toxicological research using small animal models, and in ecophysiological research using wild species where sample volume is limiting, sensitive methods are needed. In this study, we developed a nanoLC-MS/MS method enabling quantification of low concentrations of two key THs, thyroxine (T4) and 3,3',5-triiodothyronine (T3). The method was tested with egg yolk samples. We used a low flow rate (300 nl/min) to obtain maximal sensitivity of the method. The limit of quantitation was 10.6 amol for T4 and 17.9 amol for T3. The method shows good linearity (r > 0.99), repeatability and reproducibility (CVs

Maternal hormones deposited in the egg can provide a powerful model for the study of maternal effects. The differential amount of maternal hormones in the yolk of freshly laid eggs is assumed to represent differential maternal allocation. However, some evidence suggests that these amounts do not reflect maternal allocation that in fact takes place before ovulation. We compared the amounts of a wide array of gonadal steroids and their metabolites in the yolk of pre-ovulatory follicles with those of freshly laid eggs of rock pigeons using mass spectrometry. We found that between the follicle and egg stages the levels of progesterone increase whereas androstenedione and testosterone decrease in which the strength of decrease was dependent on the laying order of the egg. For conjugated estrone the change between follicle and egg differed in direction for first and second laying position yielding a significant interaction effect. For conjugated testosterone the interaction did not reach but was close to significance. This extremely early steroid metabolism was not due to maternal enzymes in the yolk as indicated by incubation of pre-ovulatory yolks treated with proteinase-K, a protein digesting enzyme. The results have significant consequences for the functional and evolutionary interpretation as well as experimental manipulation of hormone-mediated maternal effects.

WOS:000435090700050; International audience; European eel (Anguilla anguilla) is a euryhaline species, that has adapted to cope with both, hyper- and hypo-osmotic environments. This study investigates the effect of salinity, from a morphological and molecular point of view on European eel larvae reared from 0 to 12 days post hatch (dph). Offspring reared in 36 practical salinity units (psu; control), were compared with larvae reared in six scenarios, where salinity was decreased on 0 or 3 dph and in rates of 1, 2 or 4 psu/day, towards iso-osmotic conditions. Results showed that several genes relating to osmoregulation (nkcc2 alpha, nkcc2 beta, aqp1dup, aqpe), stress response (hsp70, hsp90), and thyroid metabolism (thr alpha A, thr alpha B, thr beta B, diol, dio2, dio3) were differentially expressed throughout larval development, while nkcc1 alpha, nkcc2 beta, aqp3, aqp 1dup, aqpe, hsp90, thr alpha A and dio3 showed lower expression in response to the salinity reduction. Moreover, larvae were able to keep energy metabolism related gene expression (atp6, cox1) at stable levels, irrespective of the salinity reduction. As such, when reducing salinity, an energy surplus associated to reduced osmoregulation demands and stress (lower nkcc, aqp and hsp expression), likely facilitated the observed increased survival, improved biometry and enhanced growth efficiency. Additionally, the salinity reduction decreased the amount of severe deformities such as spinal curvature and emaciation but also induced an edematous state of the larval heart, resulting in the most balanced mortality/deformity ratio when salinity was decreased on 3 dph and at 2 psu/day. However, the persistency of the pericardial edema and if or how it represents an obstacle in further larval development needs to be further clarified. In conclusion, this study clearly showed that salinity reduction regimes towards iso-osmotic conditions facilitated the European eel pre-leptocephalus development and revealed the existence of highly sensitive and regulated osmoregulation processes at such early life stage of this species.

Squamate reptiles constitute a major component of the world’s terrestrial vertebrate diversity, encompassing many morphotypes related to ecological specialization. Specifically, Gekkota, the sister clade to most other squamates, have highly specialized autopodia, which have been linked to their ecological plasticity. In this study, a developmental staging table of the gecko Hemidactylus, housed at the Museum für Naturkunde, is established. Twelve post-ovipositional stages are erected, monitoring morphological embryological transitions in eye, ear, nose, heart, limbs, pharyngeal arches, and skin structures. Ecomorphological specializations in the limbs include multiple paraphalanges, hypothesized to aid in supporting the strong muscles, that are situated adjacent to metacarpal and phalangeal heads. Furthermore, some phalanges are highly reduced in manual digits III and IV and pedal digits III, IV, and V. Development, composition, and growth of limb elements is characterized in detail via µCT, histochemistry, and bone histological analysis. Using known life history data from two individuals, we found an average lamellar bone accretion rate in the humeral diaphysis comparable to that of varanids. Various adult individuals also showed moderate to extensive remodeling features in their long bone cortices, indicating that these animals experience a highly dynamic bone homeostasis during their growth, similar to some other medium-sized to large squamates. This study of in-ovo development of the gecko Hemidactylus and its ecomorphological specializations in the adult autopodia, enlarges our knowledge of morphological trait evolution and of limb diversity within the vertebrate phylum.

The rise of the Evo-Devo field and the development of multidisciplinary research tools at various levels of biological organization have led to a growing interest in researching for new non-model organisms. Squamates (lizards and snakes) are particularly important for understanding fundamental questions about the evolution of vertebrates because of their high diversity and evolutionary innovations and adaptations that portrait a striking body plan change that reached its extreme in snakes. Yet, little is known about the intricate connection between phenotype and genotype in squamates, partly due to limited developmental knowledge and incomplete characterization of embryonic development. Surprisingly, squamate models have received limited attention in comparative developmental studies, and only a few species examined so far can be considered as representative and appropriate model organism for mechanistic Evo-Devo studies. Fortunately, the agamid lizard Pogona vitticeps (central bearded dragon) is one of the most popular, domesticated reptile species with both a well-established history in captivity and key advantages for research, thus forming an ideal laboratory model system and justifying his recent use in reptile biology research. We first report here the complete post-oviposition embryonic development for Pogona vitticeps based on standardized staging systems and external morphological characters previously defined for squamates. Whereas the overall morphological development follows the general trends observed in other squamates, our comparisons indicate major differences in the developmental sequence of several tissues, including early craniofacial characters. Detailed analysis of both embryonic skull development and adult skull shape, using a comparative approach integrating CT-scans and gene expression studies in Pogona vitticeps as well as comparative embryology and 3D geometric morphometrics in a large dataset of lizards and snakes, highlights the extreme adult skull shape of Pogona vitticeps and further indicates that heterochrony has played a key role in the early development and ossification of squamate skull bones. Such detailed studies of embryonic character development, craniofacial patterning, and bone formation are essential for the establishment of well-selected squamate species as Evo-Devo model organisms. We expect that Pogona vitticeps will continue to emerge as a new attractive model organism for understanding developmental and molecular processes underlying tissue formation, morphology, and evolution.

Over the next century, climate change of anthropogenic origin is a major threat to global biodiversity. We show here that developmental temperature can have significant effects on zebrafish cardiac anatomy and swimming performance. Zebrafish embryos were subjected to three developmental temperature treatments (TD = 24, 28 or 32 °C) up to metamorphosis and then all maintained under common conditions (28 °C) to adulthood. We found that developmental temperature affected cardiac anatomy of juveniles and adults even eight months after the different thermal treatments had been applied. The elevation of TD induced a significant increase of the ventricle roundness in juvenile (10% increase) and male (22% increase), but not in female zebrafish. The aerobic exercise performance of adult zebrafish was significantly decreased as TD elevated from 24 to 32 °C. Gene expression analysis that was performed at the end of the temperature treatments revealed significant up-regulation of nppa, myh7 and mybpc3 genes at the colder temperature. Our work provides the first evidence for a direct link between developmental temperature and cardiac form at later life-stages. Our results also add to the emerging rationale for understanding the potential effects of global warming on how fish will perform in their natural environment.

WOS:000426336600006; International audience; Thyroid hormones (THs) are key regulators of growth, development, and metabolism in vertebrates and influence early life development of fish. TH is produced in the thyroid gland (or thyroid follicles) mainly as T4 (thyroxine), which is metabolized to T3 (3,5,3'-triiodothyronine) and T2 (3,5-diiodothyronine) by deiodinase (DIO) enzymes in peripheral tissues. The action of these hormones is mostly exerted by binding to a specific nuclear thyroid hormone receptor (THR). In this study, we i) cloned and characterized thr sequences, ii) investigated the expression pattern of the different subtypes of thrs and dios, and iii) studied how temperature affects the expression of those genes in artificially produced early life history stages of European eel (Anguilla anguilla), reared in different thermal regimes (16, 18, 20 and 22 degrees C) from hatch until first-feeding. We identified 2 subtypes of thr (thr alpha and thr beta) with 2 isoforms each (thr alpha A, thr alpha B, thr beta A, thr beta beta) and 3 subtypes of deiodinases (dio1, dio2, dio3). All thr genes identified showed high similarity to the closely related Japanese eel (Anguilla japonica). We found that all genes investigated in this study were affected by larval age (in real time or at specific developmental stages), temperature, and/or their interaction. More specifically, the warmer the temperature the earlier the expression response of a specific target gene. In real time, the expression profiles appeared very similar and only shifted with temperature. In developmental time, gene expression of all genes differed across selected developmental stages, such as at hatch, during teeth formation or at first-feeding. Thus, we demonstrate that thrs and dios show sensitivity to temperature and are involved in and during early life development of European eel.

WOS: 000437400900017, Science Citation Index Expanded, The present study determined changes in protease, alpha-amylase and lipase activities during embryonic and post-embryonic developmental stages of the freshwater crayfish Astacus leptodactylus Eschscholtz, 1823. The embryonic stages studied comprised Phase Ill (blastula formation), Phase X (embryos with anlagen of masticatory) and Phase XIV (embryos with strongly developed posterior hepatopancreas lobes). The post-embryonic stages comprised Stage I (no feeding) and Stage II (prior to the onset of feeding). Protease and alpha-amylase activities were relatively high as compared with lipase activity. Protease activity values showed a steady increase from Phase III to Stage I. alpha-amylase and lipase activities were low in Phase XIV. The activities of these two enzymes tended to increase just before hatching and reached the highest levels in Stage II. Digestive enzyme activities increased in accordance with maturation of the hepatopancreas and prior to the onset of external feeding. Protease activity was high in the early stage of embryonic development and continued to increase in later stages. On the other hand, alpha-amylase and lipase activities were low until maturation of the hepatopancreas and then remained high. The results of the present study provide important information on changes in digestive enzyme levels during different developmental stages of A. leptodactylus.

Optical clearing methods can facilitate deep optical imaging in biological tissue by reducing light scattering and this has enabled accurate three-dimensional signal visualization and quantification of complex biological structures. Unfortunately, existing optical clearing approaches present a compromise between maximizing clearing capability, the preservation of fluorescent protein emission and membrane integrity and the speed of sample processing – with the latter typically requiring weeks for cm scale tissue samples. To address this challenge, we present a new, convenient, aqueous optical clearing agent, termed UbasM: Urea-Based Amino-Sugar Mixture, that rapidly renders fixed tissue samples highly transparent and reliably preserves emission from fluorescent proteins and lipophilic dyes in membrane integrity preserved tissues. UbasM is simple, inexpensive, reproducible and compatible with all labeling methods that we have encountered. It can enable convenient, volumetric imaging of tissue up to the scale of whole adult mouse organs and should be useful for a wide range of light microscopy and tomography techniques applied to biomedical research, especially the study on organism-level systems biology at multiple levels.

Salamanders are capable of regenerating amputated limbs by generating a mass of lineage-restricted cells called a blastema. Blastemas only generate structures distal to their origin unless treated with retinoic acid (RA), which results in proximodistal (PD) limb duplications. Little is known about the transcriptional network that regulates PD duplication. In this study, we target specific retinoic acid receptors (RARs) to either PD duplicate (RA treatment or RARγ agonist) or truncate (RARβ antagonist) regenerating limbs. RARE-EGFP reporter axolotls showed divergent reporter activity in limbs undergoing PD duplication versus truncation, suggesting differences in patterning and skeletal regeneration. Transcriptomics identified expression patterns that explain PD duplication, including upregulation of proximal homeobox gene expression and silencing of distal-associated genes, whereas limb truncation was associated with disrupted skeletal differentiation. RARβ antagonism in uninjured limbs induced a loss of skeletal integrity leading to long bone regression and loss of skeletal turnover. Overall, mechanisms were identified that regulate the multifaceted roles of RARs in the salamander limb including regulation of skeletal patterning during epimorphic regeneration, skeletal tissue differentiation during regeneration, and homeostatic regeneration of intact limbs. ispartof: DEVELOPMENT vol:144 issue:4 pages:601-611 ispartof: location:England status: published

PLoS one 12(3), e0174384 (2017). doi:10.1371/journal.pone.0174384, Published by PLoS, Lawrence, Kan.

Background The identification of DNA methyltransferases (Dnmt) expression patterns during development and their regulation is important to understand the epigenetic mechanisms that modulate larval plasticity in marine fish. In this study, dnmt1 and dnmt3 paralogs were identified in the flatfish Solea senegalensis and expression patterns in early developmental stages and juveniles were determined. Additionally, the regulation of Dnmt transcription by a specific inhibitor (5-aza-2′-deoxycytidine) and temperature was evaluated. Results Five paralog genes of dnmt3, namely dnmt3aa, dnmt3ab, dnmt3ba, dnmt3bb.1 and dnmt3bb.2 and one gene for dnmt1 were identified. Phylogenetic analysis revealed that the dnmt gene family was highly conserved in teleosts and three fish-specific genes, dnmt3aa, dnmt3ba and dnmt3bb.2 have evolved. The spatio-temporal expression patterns of four dnmts (dnmt1, dnmt3aa, dnmt3ab and dnmt3bb.1) were different in early larval stages although all of them reduced expression with the age and were detected in neural organs and dnmt3aa appeared specific to somites. In juveniles, the four dnmt genes were expressed in brain and hematopoietic tissues such as kidney, spleen and gills. Treatment of sole embryos with 5-aza-2′-deoxycytidine down-regulated dntm1 and up-regulated dntm3aa. Moreover, in lecithotrophic larval stages, dnmt3aa and dnmt3ab were temperature sensitive and their expression was higher in larvae incubated at 16 °C relative to 20 °C. Conclusion Five dnmt3 and one dnmt1 paralog were identified in sole and their distinct developmental and tissue-specific expression patterns indicate that they may have different roles during development. The inhibitor 5-aza-2′-deoxycytidine modified the transcript abundance of dntm1 and dntm3aa in embryos, which suggests that a regulatory feedback mechanism exists for these genes. The impact of thermal regime on expression levels of dnmt3aa and dnmt3ab in lecithotrophic larval stages suggests that these paralogs might be involved in thermal programing.

WOS:000407548800031; International audience; Temperature is important for optimization of rearing conditions in aquaculture, especially during the critical early life history stages of fish. Here, we experimentally investigated the impact of temperature (16, 18, 20, 22 and 24 degrees C) on thermally induced phenotypic variability, from larval hatch to first-feeding, and the linked expression of targeted genes [heat shock proteins (hsp), growth hormone (gh) and insulin-like growth factors (igf)] associated to larval performance of European eel, Anguilla anguilla. Temperature effects on larval morphology and gene expression were investigated throughout early larval development (in real time from 0 to 18 days post hatch) and at specific developmental stages (hatch, jaw/teeth formation, and first-feeding). Results showed that hatch success, yolk utilization efficiency, survival, deformities, yolk utilization, and growth rates were all significantly affected by temperature. In real time, increasing temperature from 16 to 22 degrees C accelerated larval development, while larval gene expression patterns (hsp70, hsp90, gh and igf-1) were delayed at cold temperatures (16 degrees C) or accelerated at warm temperatures (20-22 degrees C). All targeted genes (hsp70, hsp90, gh, igf-1, igf-2a, igf-2b) were differentially expressed during larval development. Moreover, expression of gh was highest at 16 degrees C during the jaw/teeth formation, and the first-feeding developmental stages, while expression of hsp90 was highest at 22 degrees C, suggesting thermal stress. Furthermore, 24 degrees C was shown to be deleterious (resulting in 100% mortality), while 16 degrees C and 22 degrees C (similar to 50 and 90% deformities respectively) represent the lower and upper thermal tolerance limits. In conclusion, the high survival, lowest incidence of deformities at hatch, high yolk utilization efficiency, high gh and low hsp expression, suggest 18 degrees C as the optimal temperature for offspring of European eel. Furthermore, our results suggest that the still enigmatic early life history stages of European eel may inhabit the deeper layer of the Sargasso Sea and indicate vulnerability of this critically endangered species to increasing ocean temperature.

Vertebrate cranial placodes are crucial contributors to the vertebrate cranial sensory apparatus. Their evolutionary origin has attracted much attention from evolutionary and developmental biologists, yielding speculation and hypotheses concerning their putative homologues in other lineages and the developmental and genetic innovations that might have underlain their origin and diversification. In this article we first briefly review our current understanding of placode development and the cell types and structures they form. We next summarise previous hypotheses of placode evolution, discussing their strengths and caveats, before considering the evolutionary history of the various cell types that develop from placodes. In an accompanying review, we also further consider the evolution of ectodermal patterning. Drawing on data from vertebrates, tunicates, amphioxus, other bilaterians and cnidarians, we build these strands into a scenario of placode evolutionary history and of the genes, cells and developmental processes that underlie placode evolution and development.

International audience; Data regarding the link between DNA integrity of germ cells and the quality of progeny in fish exposed to genotoxicant are scarce although such information is of value to understand genotoxic effects of contaminants in aquatic fauna. This work aimed at studying the consequences of a parental exposure during the breeding season on offspring quality in three-spined stickleback. After in vivo exposure of adult fish to methyl methane sulfonate, a model alkylating compound, a clear increase in DNA damage was observed in erythrocytes of both genders, here used as a biomarker of exposure. MMS exposure significantly affected sperm DNA integrity but neither female fecundity nor fertilization success. In order to understand the contribution of each sex to potential deleterious effects in progeny due to parental exposure, mating of males and females exposed or not to MMS, was carried out. Exposure of both males and females or of males alone led to a significant increase in both mortality during embryo-larval stages and abnormality rate at hatching that appeared to be sensitive stages. Thus, in accordance with recent studies carried out in other freshwater fish species, such development defects in progeny were clearly driven by male genome, known to be devoid of DNA repair capacity in spermatozoa. The next step will be to investigate the link between DNA damage in stickleback sperm and reproductive impairment in natural populations exposed to complex mixture of genotoxicants.

Mutations in a number of genes have been linked to inherited dilated cardiomyopathy (DCM). However, such mutations account for only a small proportion of the clinical cases emphasising the need for alternative discovery approaches to uncovering novel pathogenic mutations in hitherto unidentified pathways. Accordingly, as part of a large-scale N-ethyl-N-nitrosourea mutagenesis screen, we identified a mouse mutant, Python, which develops DCM. We demonstrate that the Python phenotype is attributable to a dominant fully penetrant mutation in the dynamin-1-like (Dnm1l) gene, which has been shown to be critical for mitochondrial fission. The C452F mutation is in a highly conserved region of the M domain of Dnm1l that alters protein interactions in a yeast two-hybrid system, suggesting that the mutation might alter intramolecular interactions within the Dnm1l monomer. Heterozygous Python fibroblasts exhibit abnormal mitochondria and peroxisomes. Homozygosity for the mutation results in the death of embryos midway though gestation. Heterozygous Python hearts show reduced levels of mitochondria enzyme complexes and suffer from cardiac ATP depletion. The resulting energy deficiency may contribute to cardiomyopathy. This is the first demonstration that a defect in a gene involved in mitochondrial remodelling can result in cardiomyopathy, showing that the function of this gene is needed for the maintenance of normal cellular function in a relatively tissue-specific manner. This disease model attests to the importance of mitochondrial remodelling in the heart; similar defects might underlie human heart muscle disease., Author Summary Heart disease is very common. Some cases of heart disease are strongly influenced by lifestyle and diet, whereas others have a strong genetic component. A certain form of heart failure, known as dilated cardiomyopathy (DCM) quite often runs in families suggesting that a defective gene or genes underlie this disease. We describe a new mouse mutant called “Python” which suffers from a heart disease similar to DCM. We were able to pinpoint the defective gene responsible for the disease. This gene is normally involved in the division of mitochondria, the “power plants” of the cell that generate one of the main energy supplies for the cell. This is a unique model that implicates a new gene and mechanism of disease for further investigation.

Inappropriate activation of the Wnt/β-catenin pathway has been indicated in podocyte dysfunction and injury, and shown to contribute to the development and progression of nephropathy. Tankyrases, multifunctional poly(ADP-ribose) polymerase (PARP) superfamily members with features of both signaling and cytoskeletal proteins, antagonize Wnt/β-catenin signaling. We found that tankyrases interact with CD2-associated protein (CD2AP), a protein essential for kidney ultrafiltration as CD2AP-knockout (CD2AP−/−) mice die of kidney failure at the age of 6–7 weeks. We further observed that tankyrase-mediated total poly-(ADP-ribosyl)ation (PARylation), a post-translational modification implicated in kidney injury, was increased in mouse kidneys and cultured podocytes in the absence of CD2AP. The data revealed increased activity of β-catenin, and upregulation of lymphoid enhancer factor 1 (LEF1) (mediator of Wnt/β-catenin pathway) and fibronectin (downstream target of Wnt/β-catenin) in CD2AP−/− podocytes. Total PARylation and active β-catenin were reduced in CD2AP−/− podocytes by tankyrase inhibitor XAV939 treatment. However, instead of ameliorating podocyte injury, XAV939 further upregulated LEF1, failed to downregulate fibronectin and induced plasminogen activator inhibitor-1 (PAI-1) that associates with podocyte injury. In zebrafish, administration of XAV939 to CD2AP-depleted larvae aggravated kidney injury and increased mortality. Collectively, the data reveal sustained activation of the Wnt/β-catenin pathway in CD2AP−/− podocytes, contributing to podocyte injury. However, we observed that inhibition of the PARylation activity of tankyrases in the absence of CD2AP was deleterious to kidney function. This indicates that balance of the PARylation activity of tankyrases, maintained by CD2AP, is essential for normal kidney function. Furthermore, the data reveal that careful contemplation is required when targeting Wnt/β-catenin pathway to treat proteinuric kidney diseases associated with impaired CD2AP.

Thyroid hormones (THs) - triiodothyronine (T3) and thyroxine (T4) - are essential for embryonic development in vertebrates. All vertebrate embryos are exposed to THs from maternal origin. As maternal TH levels are known to be essential to embryonic development, the natural variation of maternal THs probably represents a pathway of maternal effects that can modify offspring phenotype. However, potential fitness consequences of variation of maternal TH exposure within the normal physiological range and without confounding effects of the mother have never been experimentally investigated. We experimentally manipulated the levels of yolk T3 and T4 within the physiological range in a species in which the embryo develops outside the mother's body, the Rock Pigeon (Columba livia) eggs. Making use of the natural difference of yolk testosterone between the two eggs of pigeon clutches, we were also able to investigate the potential interaction between THs and testosterone. Elevated yolk TH levels enhanced embryonic development and hatching success, and reduced body mass but not tarsus length between day 14 and fledging. The yolk hormones increased plasma T4 concentrations in females but reduced it in males, in line with the effect on metabolic rate at hatching. Plasma concentrations of T3 and testosterone were not significantly affected. The effects of treatment did not differ between eggs with high or low testosterone levels. Our data indicate that natural variation in maternal yolk TH levels affects offspring phenotype and embryonic survival, potentially influencing maternal and chick fitness. (C) 2016 Elsevier Inc. All rights reserved.

International audience; Cilia use microtubule-based intraflagellar transport (IFT) to organize intercellular signaling. Ciliopathies are a spectrum of human diseases resulting from defects in cilia structure or function. The mechanisms regulating the assembly of ciliary multiprotein complexes and the transport of these complexes to the base of cilia remain largely unknown. Combining proteomics, in vivo imaging and genetic analysis of proteins linked to planar cell polarity (Inturned, Fuzzy and Wdpcp), we identified and characterized a new genetic module, which we term CPLANE (ciliogenesis and planar polarity effector), and an extensive associated protein network. CPLANE proteins physically and functionally interact with the poorly understood ciliopathy-associated protein Jbts17 at basal bodies, where they act to recruit a specific subset of IFT-A proteins. In the absence of CPLANE, defective IFT-A particles enter the axoneme and IFT-B trafficking is severely perturbed. Accordingly, mutation of CPLANE genes elicits specific ciliopathy phenotypes in mouse models and is associated with ciliopathies in human patients.

In oviparous species like birds, eggs provide the direct environment in which embryos are developing. Mothers may adjust different egg components in different ways in reaction to environmental cues either to adjust offspring development or because of constraints. In this study, we investigated the effects of food quality and quantity before and during egg laying on three different aspects of egg quality: macro-nutrients (egg and yolk mass), androgens (testosterone and androstenedione), and thyroid hormones (3,5,3'-triiodothyronine, T3 and l-thyroxine, T4), using the rock pigeon (Columba livia). As expected, egg and yolk mass were significantly reduced for the eggs laid under the poor-food condition, indicating a maternal trade-off between offspring and self in allocating important resources. We did not find any significant change in yolk testosterone or their within-clutch pattern over the laying sequence. This is consistent with the fact that, in contrast with nutrients, these hormones are not costly to produce, but does not support the hypothesis that they play a role in adjusting brood size to food conditions. In contrast, we found that T3 levels were higher in the egg yolks under the poor-food condition whereas the total T4 content was lower. This change could be related to the fact that iodine, the critical constituent of thyroid hormones, might be a limiting factor in the production of this hormone. Given the knowledge that food restriction usually lead to reduction of circulating T3 levels, our results suggested that avian mothers can independently regulate its concentrations in their eggs from their own circulation. The study demonstrates that environmentally induced maternal effects via the egg can be a result of a combination of constrained resources and unconstrained signals and that thyroid hormones might be an interesting case of both. Therefore, this hormone and the interplay of different maternal effects on the offspring phenotype deserve much more attention. ispartof: Ecology and Evolution vol:6 issue:2 pages:397-411 ispartof: location:England status: published

Zebrafish lost anterior teeth during evolution but retain a posterior pharyngeal dentition that requires retinoic acid (RA) cell-cell signaling for its development. The purposes of this study were to test the sufficiency of RA to induce tooth development and to assess its role in evolution. We found that exposure of embryos to exogenous RA induces a dramatic anterior expansion of the number of pharyngeal teeth that later form and shifts anteriorly the expression patterns of genes normally expressed in the posterior tooth-forming region, such as pitx2 and dlx2b. After RA exposure, we also observed a correlation between cartilage malformations and ectopic tooth induction, as well as abnormal cranial neural crest marker gene expression. Additionally, we observed that the RA-induced zebrafish anterior teeth resemble in pattern and number the dentition of fish species that retain anterior pharyngeal teeth such as medaka but that medaka do not express the aldh1a2 RA-synthesizing enzyme in tooth-forming regions. We conclude that RA is sufficient to induce anterior ectopic tooth development in zebrafish where teeth were lost in evolution, potentially by altering neural crest cell development, and that changes in the location of RA synthesis correlate with evolutionary changes in vertebrate dentitions.-Seritrakul, P., Samarut, E., Lama, T. T. S., Gibert, Y., Laudet, V., Jackman, W. R. Retinoic acid expands the evolutionarily reduced dentition of zebrafish. FASEB J. 26, 5014-5024 (2012). www.fasebj.org

The quality of day old chicks is crucial for profitable broiler production, but a difficult trait to define. In research, both qualitative and quantitative measures are used with variable predictive value for subsequent performance. In hatchery practice, chick quality is judged on a binomial scale, as chicks are divided into first grade (Q1-saleable) and second grade (Q2) chicks right after hatch. Incidences and reasons for classifying chicks as Q2, and potential of these chicks for survival and post-hatch performance have hardly been investigated, but may provide information for flock performance. We conducted an experiment to investigate (1) the quality of a broiler flock and the relation with post-hatch flock performance based on a qualitative score (Pasgar©score) of Q1 chicks and based on the incidence of Q2 chicks and (2) the reasons for classifying chicks as Q2, and the potential of these chicks for survival and post-hatch growth. The performance was followed of Q1 and Q2 chicks obtained from two breeder flocks that hatched in two different hatching systems (a traditional hatcher or a combined hatching and brooding system, named Patio). Eggs were incubated until embryo day 18, when they were transferred to one of the two hatching systems. At embryo day 21/post-hatch day 0, all chicks from the hatcher (including Q2 chicks) were brought to Patio, where the hatchery manager marked the Q2 chicks from both flocks and hatching systems and registered apparent reasons for classifying these chicks as Q2. Chick quality was assessed of 100 Q1 chicks from each flock and hatching system. Weights of all chicks were determined at days 0, 7, 21 and 42. There were no correlations between mean Pasgar©score and post-hatch growth or mortality, and suboptimal navel quality was the only quality trait associated with lower post-hatch growth. Growth was clearly affected by breeder flock and hatching system, which could not be linked to mean Pasgar©score or incidence of Q2 chicks. Q2 chicks showed lower post-hatch growth compared to Q1 chicks but effects on flock performance at slaughter weight were limited because early mortality in Q2 chicks was high (62.50% at 7 days). We concluded that chick qualitative scores and the incidence of Q2 chicks may be informative for the quality of incubation, but are not predictive for post-hatch flock performance. Culling Q2 chicks after hatch is well-founded in terms of both animal welfare and profitability.

The E2F family of transcription factors plays an important role in controlling cell-cycle progression. While this is their best-known function, we report here novel functions for the newest members of the E2F family, E2F7 and E2F8 (E2F7/8). We show that simultaneous deletion of E2F7/8 in zebrafish and mice leads to severe vascular defects during embryonic development. Using a panel of transgenic zebrafish with fluorescent-labelled blood vessels, we demonstrate that E2F7/8 are essential for proper formation of blood vessels. Despite their classification as transcriptional repressors, we provide evidence for a molecular mechanism through which E2F7/8 activate the transcription of the vascular endothelial growth factor A (VEGFA), a key factor in guiding angiogenesis. We show that E2F7/8 directly bind and stimulate the VEGFA promoter independent of canonical E2F binding elements. Instead, E2F7/8 form a transcriptional complex with the hypoxia inducible factor 1 (HIF1) to stimulate VEGFA promoter activity. These results uncover an unexpected link between E2F7/8 and the HIF1-VEGFA pathway providing a molecular mechanism by which E2F7/8 control angiogenesis.

Although most work on prenatal stress has been conducted on mammalian species, birds provide useful alternative models since avian embryos develop outside the mother's body in a concealed environment, the egg, which is produced during a short time window of 4-14 days. This facilitates measurement of maternal substances provided for and manipulation of the embryo without interfering with the mother's physiology. We critically review prenatal corticosterone mediated effects in birds by reviewing both studies were females had elevated levels of plasma corticosterone during egg formation and studies applying corticosterone injections directly into the egg. A selected review of the mammalian literature is used as background. The results suggest that besides prenatal exposure to corticosterone itself, maternal corticosterone affects offspring's behaviour and physiology via alteration of other egg components. However, results are inconsistent, perhaps due to the interaction with variation in the post-natal environment, sex, age, developmental mode and details of treatment. The potential role of adaptive maternal programming has not been tested adequately and suggestions for future research are discussed. (C) 2011 Published by Elsevier Ltd.

Although most work on prenatal stress has been conducted on mammalian species, birds provide useful alternative models since avian embryos develop outside the mother's body in a concealed environment, the egg, which is produced during a short time window of 4-14 days. This facilitates measurement of maternal substances provided for and manipulation of the embryo without interfering with the mother's physiology. We critically review prenatal corticosterone mediated effects in birds by reviewing both studies were females had elevated levels of plasma corticosterone during egg formation and studies applying corticosterone injections directly into the egg. A selected review of the mammalian literature is used as background. The results suggest that besides prenatal exposure to corticosterone itself, maternal corticosterone affects offspring's behaviour and physiology via alteration of other egg components. However, results are inconsistent, perhaps due to the interaction with variation in the post-natal environment, sex, age, developmental mode and details of treatment. The potential role of adaptive maternal programming has not been tested adequately and suggestions for future research are discussed. (C) 2011 Published by Elsevier Ltd.

As a trace element, copper has a crucial role in mammalian metabolism, but it can be toxic in excess. The importance of a balanced copper homeostasis is illustrated by several copper-associated disorders in man, such as Menkes and Wilson disease, and in a wide variety of animal models (eg, mice, dogs, and sheep). Proteins involved in controlling copper metabolism have been well studied in yeast and in vitro. Recently, naturally occurring mutants and transgenic mouse models have been used to study the physiologic role of copper transporters in copper homeostasis. We discuss the most common mammalian animal models used to study copper-related diseases, evaluate what these model systems have recently shown about copper metabolism, and discuss the importance of these models for identifying specific and sensitive biomarkers associated with copper status in the near future.

Regulatory mechanisms controlling the timing of developmental events are crucial for proper development to occur. ftz-fl is expressed in a temporally regulated manner following pulses of ecdysteroid and this precise expression is necessary for the development of Drosophila melanogaster. To understand how insect hormone ecdysteroids regulate the timing of FTZ-F1 expression, we purified a DNA binding regulator of ftz-fl. Mass spectroscopy analysis revealed this protein to be a fly homolog of mammalian B lymphocyte-induced maturation protein 1 (Blimp-1). Drosophila Blimp-1 (dBlimp-1) is induced directly by 20-hydroxyecdysone, and its product exists during high-ecdysteroid periods and turns over rapidly. Forced expression of dBlimp-1 and RNA interference analysis indicate that dBlimp-1 acts as a repressor and controls the timing of FTZ-F1 expression. Furthermore, its prolonged expression results in delay of pupation timing. These results suggest that the transient transcriptional repressor dBlimp-1 is important for determining developmental timing in the ecdysone-induced pathway.

International audience; Solar ultraviolet-B (UV-B) radiation can be harmful for developing amphibians. As the UV-B dose increases with altitude, it has been suggested that high-altitude populations may have an increased tolerance to high levels of UV-B radiation as compared to lowland populations. We tested this hypothesis with the common frog (Rana temporaria) by comparing populations from nine altitudes (from 333 to 2450 in above sea level). Eggs collected in the field were used for laboratory experiments, i.e., exposed to high levels of artificial UV-B radiation. Eggs were reared at 14 +/- 2 degrees C and exposed to UV treatments until hatching. Embryonic developmental rates increased strongly and linearly with increasing altitude, suggesting a genetic capacity for faster development in highland than lowland eggs. Body length at hatching varied significantly with UV-B treatments, being lower when eggs developed under direct UV-B exposure. Body length at hatching also increased as the altitude of populations increased, but UV-B exposure times were shorter as altitude of population increased. However, the body length difference between exposed and non-exposed individuals in each population decreased as altitude of populations increased, suggesting a costly effect of UV exposure on growth. Type of UV exposure did not influence the mean rates of embryonic mortality and deformity, but both mortality and deformity rates increased as the altitude of populations increased (while UV-B exposure duration decreased). The effect of UV-B on body length at hatching, mortality, and deformities suggests that the sensitivity to UV-B varied among populations along the altitudinal gradient. These results are discussed in evolutionary terms, specifically the potential of R. temporaria high-altitude populations to develop local genetic adaptation to high levels of UV-B. (c) 2008 Elsevier GmbH. All rights reserved.

Background: Autoimmune polyendocrine syndrome type 1 (APS-1) is a multiorgan autoimmune disorder caused by mutations in AIRE, the autoimmune regulator gene. Though recent studies concerning AIRE deficiency have begun to elucidate the molecular pathogenesis of organ-specific autoimmunity in patients with APS-1, the autoantigen responsible for hypoparathyroidism, a hallmark of APS-1 and its most common autoimmune endocrinopathy, has not yet been identified. Methods: We performed immunoscreening of a human parathyroid complementary DNA library, using serum samples from patients with APS-1 and hypoparathyroidism, to identify patients with reactivity to the NACHT leucine-rich-repeat protein 5 (NALP5). Subsequently, serum samples from 87 patients with APS-1 and 293 controls, including patients with other autoimmune disorders, were used to determine the frequency and specificity of autoantibodies against NALP5. In addition, the expression of NALP5 was investigated in various tissues. Results: NALP5-specific autoantibodies were detected in 49% of the patients with APS-1 and hypoparathyroidism but were absent in all patients with APS-1 but without hypoparathyroidism, in all patients with other autoimmune endocrine disorders, and in all healthy controls. NALP5 was predominantly expressed in the cytoplasm of parathyroid chief cells. Conclusions: NALP5 appears to be a tissue-specific autoantigen involved in hypoparathyroidism in patients with APS-1. Autoantibodies against NALP5 appear to be highly specific and may be diagnostic for this prominent component of APS-1.

Maternal hormones in the yolk of birds' eggs have been a focus of attention in behavioral and evolutionary ecology stimulated by the pioneering work of Hubert Schwabl. Since then, knowledge of both the factors that influence maternal deposition patterns and their consequences for offspring development has accumulated rapidly. To date, the field has been dominated by the idea that mothers use yolk hormones to adaptively adjust offspring development, a view that assigns control over hormone deposition and its effects on the offspring to the mother. This neglects the possibility that the evolutionary interests of the mother and offspring differ. When there is such parent-offspring conflict, the offspring are selected to respond to the hormones in a way that is adaptive for themselves rather than for the mother. Moreover, sexual conflict between the parents over parental investment may shape the evolution of yolk hormone deposition: females may manipulate the male's contribution to parental care through the effect of yolk hormones on offspring begging, competitiveness, and developmental rate. We therefore suggest that for a full understanding of the evolution of hormone-mediated maternal effects, it is essential to study both fitness consequences and physiological mechanisms and constraints from the perspective of all family members.

The exciting discovery by Hubert Schwabl (Washington State University) in the early nineties that the yolk of bird eggs contains hormones originating from the mother opened up an extremely successful research area for endocrinologists and behavioral ecologists. Since then, knowledge of both the factors that influence the amount of hormones deposited in yolk by the female, and the consequences of exposure to these maternal hormones on offspring growth, physiology, and behaviour has accumulated rapidly. The field has been dominated by the idea that mothers use yolk hormones to adaptively adjust offspring development in their interest. However, this idea neglects that the (evolutionary) interests of mother and offspring may differ. Each offspring will try to maximize its share of parental investment while the mother wants to distribute her investment among all her offspring. When there is such parent-offspring conflict the offspring are selected to respond to the yolk hormones in a way that is b Parent-offspring conflict is not the only intra-familial strife that may shape the evolution of yolk hormone deposition. Parents disagree (evolutionarily) over the amount of care each of them is willing to provide to their young. Since yolk hormones affect offspring begging behavior, females may be able to use yolk hormone deposition to modify begging traits in a way that increases the amount of parental care provided by the male. The existence of sex differences in response to offspring begging The authors therefore suggest that for a full understanding of the evolution of hormone-mediated maternal effects it is essential to study both fitness consequences, and physiological mechanisms and constraints, from the perspective of all family members. Furthermore, the authors believe that the integration of evolutionary biology and endocrinology will lead to the most rapid advance in this field - from both an evolutionary and endocrinological point of view. It may therefore not be coincidenc