France

Despite ~80% of all animal species undergoing metamorphosis, the effect of this dramatic developmental process on telomere dynamics is unknown. Given that the rate of telomere shortening has been shown in non-metamorphosing species to be influenced by environmental harshness, the question arises as to whether the re-modelling of tissues that occurs during metamorphosis allows an individual to re-set its telomeres and so leave behind this legacy of past environments. This issue is pertinent to amphibians, a group likely to be heavily impacted in the larval stage (i.e., before metamorphosis) by environmental events such as global warming. We will first briefly discuss the current knowledge gaps in the study of amphibian telomeres, then present new data on telomere length across different tissues and developmental stages (from larva to adulthood) in the frog Xenopus laevis. We will also examine the impact of warming conditions before and after metamorphosis on amphibian telomeres and telomerase. Our results show that telomere length is affected not only by the rate of somatic growth, but also by the degree of metamorphic transformation experienced by particular tissues: during metamorphosis, telomere length can either decline, remain stable or dramatically increase. Furthermore, this life history transition seems to be able to buffer the impact on telomeres of harsh conditions in early life. This leads us to suggest directions for future research on telomere dynamics in amphibians and other species with complex-life cycles.

SEB Annual Conference 2022

Across the great divide: telomere dynamics through metamorphosis in amphibians

Discover the art of creating extraordinary science at SEB’s Annual Conference at Le Corum Conference Center     in Montpellier, France from 5 to  8 July 2022.

SEB’s Annual Conference is celebrated for creating the perfect composition of research, new discoveries and collaborative connections. Be creative and innovative by exchanging ideas and knowledge with masters of biology from all over the world.

2022 will find over 1500 experimental biologists from across the globe converging on the third-largest French city near the Mediterranean coast and the fastest-growing city in the country over the past 25 years.
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Please register for the conference by clicking on this link:

https://www.sebiology.org/events/seb-annual-conference-2022/registration.html

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2022 will find over 1500 experimental biologists from across the globe converging on the third-largest French city near the Mediterranean coast and the fastest-growing city in the country over the past 25 years - Montpellier, France

technical paper

Modifications in the cytochrome c oxidase 2 gene of male-transmitted genome (Mcox2) have been found in some bivalve species that exhibit a unique mode of mitochondrial transmission named doubly uniparental inheritance (DUI). In DUI, paternal mitochondria (and their male mtDNA) as well as maternal mitochondria (and their corresponding female mtDNA) are transmitted to male offspring. Scrobicularia plana, a bivalve exhibiting this inheritance model possess an important in-frame insertion of ~ 4,8 kb in its Mcox2 gene that is translated into a polypeptide of 1892 amino acids (~ 220 kDa), the largest metazoan COX2 protein known to date. The insertion is conserved amongst individuals from different populations and, according to analysis of synonymous and non-synonymous substitution rates, evolves under purifying selection which would suggest maintenance of functionality in MCOX2. MCOX2 protein might act as a tag at the surface of male mitochondria to facilitate their sex-specific fate in bivalve embryos. The long-transcribed insertion could also explain low OXPHOS rates that were found in M mitochondria of DUI bivalves thus affecting male mitochondrial metabolism.

Mcox2 in the DUI bivalve Scrobicularia plana encodes the longest known mitochondrial protein in metazoans

The Atlantic salmon (Salmo salar) is a unique species with regards to studies on life history, as it not only shows significant variation in age at maturity but also because a large proportion of the variation in this trait has been associated with a single genetic locus, vgll3. While this association is now well known, less is known about this gene’s mechanistic pathway and how it interacts with other environmental or genetic factors. To follow up on vgll3 as a large-effect locus for age at maturity in Atlantic salmon, we present a long-term common garden experiment aimed at studying the sources of variation for this trait, covering different vgll3 genotypes across two environmental temperature regimes, two feed treatments, and two populations-of-origin. We show that the effect of vgll3 genotype on maturation timing in male Atlantic salmon is consistent across the temperature treatments and populations. Additionally, we show a population-dependent effect of temperature, with the northern population having a smaller difference in maturation rates between the two temperature regimes. Finally, we discuss the relative contribution of these environmental and genetic factors to Atlantic salmon maturation timing.

Atlantic salmon maturation: contributions from large-effect locus and environmental factors in influencing maturation age in two populations in a common garden setting.

Acidified ocean system would affect marine livings was already proved. The inadequate potential difference and ions gradient may jam the neural transmitting in turn; moreover, the evoking pathological behavioral defects such as impaired visual capacity may impact the survival and fitness of several marine species. As such, the electrophysiological method, electro-retinography (ERG), is one of the most commonly used techniques to investigate the properties of the visual response to a light stimulus in aquatic animals. A simplified and low-cost ERG apparatus was assembled and used to determine the threshold of flicker electroretinogram (fERG) of bigfin reef squid under control (pH 8.1) or laboratory CO2-induced acidified conditions at the retinal level. An epoxy-insulated tungsten microelectrode was placed on the midline of the retina and enabled us to estimate the visual sensitivities practically in squid retina to a series of light-emitting diodes (LEDs) emitting different wavelengths. Under the control pH 8.1 conditions, the average critical flicker fusion (CFF) threshold toward a white light source in bigfin reef squid retina was found to be 47 Hz at the illumination level of 50 cd/m2, while the average CFF of CO2-acclimated squid is slightly increased by about 15%. In the future, pharmacological studies could further indicate whether this effect could be caused by the CO2-involved neuronal functional irregularity.

A visual sensory estimation system for detecting electroretinogram in bigfin reef squid under CO2 perturbation

Chronic temperature stress may leave freshwater fishes vulnerable to opportunistic pathogens, particularly during early life stages. Lake sturgeon, Acipenser fulvescens, populations within the northern expanse of their range in Manitoba, Canada, may be susceptible to high temperature thermal stress. We acclimated developing lake sturgeon for 21 days to two ecologically relevant temperatures (16 and 20oC) . Both acclimation treatments were exposed to 0, 30, and 60 µg.ml-1 bacterial lipopolysaccharides (endotoxins), as an immune stimulus, for 48 hr, with samples taken 4 and 48 hr during trial exposures and following a 7-day recovery period. We then measured whole body transcriptional (mRNA) and physiological (lysozyme activity, cortisol, glucose) responses involved in the innate immune, general stress, and fatty acid responses following acute exposure to bacterial endotoxins. Data detailing the responses involved in the above physiological processes revealed that while overall expression levels were higher at 20oC under control conditions, during bacterial stimulus 16oC reared lake sturgeon produced a more robust response with higher induced expression of the above responses than their 20oC acclimated counterparts. Additional whole-animal performance metrics (critical thermal maximum and metabolic rate) demonstrated acclimation-specific responses indicating compromised metabolic capacity following the initiation of immune related responses. Our study showed that acclimation to 20oC during early development impaired the activation of molecular pathways involved in the immune, stress, and fatty acid responses of lake sturgeon, highlighting the effects of chronic thermal stress on transcriptional activation and recruitment of downstream biological processes in this critically threatened and endangered species.

Elevated temperatures dampen innate immune responses of developing lake sturgeon (Acipenser fulvescens) when challenged with bacterial lipopolysaccharides

Sea stars move with crawling and bouncing gaits that are generated by the action of hundreds of tube feet. Bouncing at high speed is characterized by the feet moving in synchrony, which is unlike the asynchronous and slow crawling motion. It is unclear what forces are generated by individual tube feet and how those forces coordinate to generate distinct gaits. We have therefore investigated the mechanics of locomotion in sea stars at the levels of individual feet and the whole body through a combination of experimentation and mathematical modeling. These efforts have included a definition for the mechanical advantage and gearing of helically wound hydrostatic skeletons, as well as the development of an optical under-water force plate. Our results suggest that tube feet primarily serve to push against the substratum and that the gait transition is generated by the collective dynamics of tube feet that are mechanically coupled to a common body. Therefore, the transition to synchronous bouncing may be generated purely through mechanics, without a need for a change in nervous control.






The collective mechanics and control of locomotion in sea stars

Bone trabeculae are known to remodel during the life of vertebrates, aligning themselves in accordance with the forces going through the bones. Heavy animals p resent very high forces passing through their limb bones during locomotion, through body weight and the necessarily important muscle pull associated. It is expected that their cortical and trabecular structures will adapt to those constraints, but a quantified description of how trabecular architecture varies in the limb bones of heavy animals is not available. Here we use a new approach to quantitatively and precisely describe the distribution of anisotropy and compactness of cancellous bone in the six limb long bones of all living species of rhinoceroses, the heaviest animals capable of galloping. We show that trabecular compactness and anisotropy are correlated in our sample. Highly anisotropic and compact trabeculae are concentrated along articulations and muscle insertion areas, and dissipate the forces into the more resistant cortical bone. The radius, ulna and tibia present a simple, vertical anisotropy pattern associated with body weight support (or triceps pull for the ulna), whereas the humerus and femur present a more complex trabecular pattern, linked with attachment areas for powerful muscles that generate anisotropic trabeculae in various directions. Few variations were observed between species, highlighting that rhinos share a common strategy for bone resistance allowing galloping while weighing up to three tons. Further studies on their more cursorial relatives and on fossil rhinos, some of which reached 20 tons, could yield interesting complementary results for untangling the adaptations to heavy weight and cursoriality in perissodactyls.

Whole bone distribution of trabecular compactness and anisotropy reveals how long bones sustain important forces in rhinoceroses

Genomics provide researchers with solutions to better predict the phenotypic characteristics, economic value and adaptive potential of species, and improves our understanding of the diversity present in wild populations. I will reflect on our work to develop high-quality genome assemblies and associated analyses for plant and animal species of importance to New Zealand (Aotearoa), including species that are considered as treasures (taonga) by indigenous Māori people. Specifically, I will present my perspectives and experiences as a European biologist who works in a government-owned research institution, alongside Māori communities, academics and commercial enterprises, to reflect on my journey to achieve positive impact and shared benefits with Māori using genomics research.

Plant and animal genomics research for and with indigenous communities: a European scientist’s perspective.

Examining global patterns of DSI sharing and use to inform policy

Recent changes to the legal frameworks regulating genetic resources -- including the expanding reach of ABS under the Nagoya Protocol,  and the growing number of non-State institutions developing their own ABS schemes – are having a negative impact on the collection, transfer, and use of genetic resources. The talk argues that while these are challenging issues that the stakes are too high not to attempt to find a solution, and that there is potential for researcher driven solutions to the legal uncertainty created by the Nagoya Protocol.  

Nagoya Protocol and access to genetic resources

Concerns over Indigenous Data Sovereignty and Indigenous rights under the Nagoya Protocol underpin the development and application of Traditional Knowledge and Biocultural Labels/Notices. The Local Contexts system which delivers the Labels and Notices, is focused on implementing Indigenous provenance, protocols, and permissions into digital infrastructures. The Labels and Notices are designed to provide a persistent and durable connection between collaborating Indigenous communities and researchers, research projects, genetic resources, Digital Sequence Information (DSI), and associated traditional knowledge, that exist as metadata in sample/data repositories. The Biocultural Labels support Nagoya Protocol expectations around the disclosure and origins of genetic resources (i.e. Provenance Label) and help to define and communicate Indigenous community expectations and consent about appropriate and future use of genetic resources and derived benefits. Importantly BC Labels may only be applied by an Indigenous community, and they are both human readable and machine readable. The Notices are a distinct tool for researchers who can use this mechanism to disclose Indigenous rights and interests. This presentation will introduce the Labels and Notices and explore the responsibilities that universities and researchers have to practically implement mechanisms that enable transparency around Indigenous rights and interests in support of Indigenous Data Sovereignty.

Across the great divide: telomere dynamics through metamorphosis in amphibians

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Mcox2 in the DUI bivalve Scrobicularia plana encodes the longest known mitochondrial protein in metazoans

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