Czechia

Phenotypic plasticity, both within and between generations, allows organisms to respond to a changing world. Here, we aim to investigate how paternal phenotypes interact to shape offspring life-histories, focussing on two ubiquitous animal experiences: ageing and feeding. We present preliminary results from an ongoing experiment using Drosophila melanogaster: a full-factorial design, where fathers were fed one of two diets (control and higher-sucrose) and male and female offspring collected when fathers were young (one week) and old (five weeks). These offspring were then assigned to diets either matching or mismatching those of their fathers, and their survival and weekly reproductive output measured. We find complex interactions between paternal age, paternal diet, and offspring diet shape different aspects of offspring life-history, in a sex-specific manner. This investigation illuminates how organisms cope with environmental variation over their own lifespans and between generations, exploring the myriad forms of information parents transfer to their offspring, and the conditions under which this occurs.

SEB Conference 2024

Paternal age and environment effects on offspring life-history traits and fitness in Drosophila melanogaster

drosophila melanogaster

parental effects

life-history

reproduction

diet

ageing

Colleagues and Friends:

I am very happy to welcome you to the 14th annual Canadian Neuroscience Meeting, and to the first virtual edition of our meeting. I want to highlight the important work the CAN meeting chair, **Roger Thompson** and co-chair, **Alyson Fournier**, did to put together the great program we are offering this year. Moving to a virtual format required a complete re-design of the program, and both Roger and Alyson did a splendid job in providing us with an appealing and well adapted program for our first virtual event. I wish to thank them for this very important effort.

Highlights of this year’s scientific meeting include invited speakers **Michael Hausser, Franck Polleux, Gwyneth Card, Magdalena Götz**and Brain Prize winner **Huda Zoghbi**. Plenary and parallel symposia, proposed by our members complete our diverse [scientific program.](https://can-acn.org/meeting-2021/program-2021/)

The 2021 Advocacy session, chaired and organized by CAN advocacy committee chair **Karun Singh**, will feature a special lecture and question period with Member of Parliament and past Science Minister **Kirsty Duncan**. This will be followed by a short overview of CAN’s advocacy activities over the last year. We invite you to participate in this session for insight from Dr. Duncan on the workings of Parliament Hill, and to learn more about what CAN has been doing to promote neuroscience research in Canada.

We are also excited to host **Lisa Willis** in the Equity Diversity and Inclusion session, organized by EDI committee chair **Jibran Khokhar**.

A special highlight of our meeting will be the lectures by award-winning young neuroscientists. We are please to host the CAN 2020 Young Investigator Award winner **Mihaela Iordanova**, and CAN 2021 Young Investigator Award winners **Aaron Phillips** and **Tabrez Siddiqui**. Highlights will also include presentation by the top three winners of the CAN-CIHR-INMHA Brain Star Award winners, **Claire Gizowski, Nuria Daviu Abant** and **Lukas Tamayo-Orrego**.

Independently organized satellite symposia complement and complete this exciting program, check them out here: https://can-acn.org/meeting-2021/2021-satellite-symposia/

Some of the most engaging sessions are always the poster sessions featuring the work of our trainees, so make sure to log in to Gather Town during the poster sessions to chat with the presenters.
We hope you enjoy this program, and look forward to welcoming you, virtually.

Shernaz Bamji

President of the Canadian Association for Neuroscience

![](https://assets.underline.io/uploads/markdown_image/1/image/b9aea25343a87d5aac3b9367dc780974.jpg)



Please head to https://can-acn.org/meeting-2021/registration-2021/ to register. 

CAN-ACN 2021

14th Canadian Neuroscience Meeting from August 23rd-25th

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Maintaining pH homeostasis is not only require for the biomineralization process of marine calcifiers but also essential to their adaptation streitige against the environmental challenge such as ocean acidification. The calcareous endoskeleton of sea urchin larva, which benefits from years development of gene regulatory networks, ex vivo tissue engineering technique and in vivo gene manipulation approaches, becomes a powerful model for biomineralization research. Based on the model organism Strongylocentrotus purpuratus, our research group discovered a serial transporters and enzymes that are critical to cytosolic pH (pHi) regulation in skeletogenic cells. The cytosolic bicarbonate sensor soluble adenylyl cyclase (sAC) is one of these factors which might play the central role regulating intracellular pH homeostasis. The cAMP signaling triggered by activated sAC may further stimulates the channel activity and gene expression of pH effectors in skeletogenic cell. In order to investigate the interaction between cAMP signaling and pH-regulating transporters, we developed skeletogenic cell-specific gene expression approaches. According to our preliminary results, the activity of sAC is possibly regulated through its alternative splicing, and the splicing event is stimulated by skeleton regeneration. Further evidences are required to clarify the regulation of sAC splicing event and cytosolic pH homeostasis that initiated by cAMP signaling. The present study demonstrates a canonical cellular stress response that a sensory factor reacts to environmental stimulation through post-transcriptional modification.

Soluble adenylyl cyclase regulates intracellular pH homeostasis of calcifying cells in the sea urchin larva.

A marine biogeographic and phylogeographic break around 30°S along the shores of the southeastern Pacific coincides with a mesoscale change in coastal upwelling regime. Prior ecological and genetic evidence indicated that dispersal limitation was the leading mechanism maintaining the break. Recent evidence of large environmental heterogeneity between sites along the transitional zone provides support for a niche-based mechanism as the underlying driver. To test this hypothesis, we examined patterns of phenotypic plasticity under contrasting thermal conditions for species belonging to several taxa and multiple trophic levels, which were sourced from local populations spanning the biogeographic break. We pooled plasticity patterns with data from similar studies over multiple sites spanning the break and examined their joint spatial structure and its relationship with environmental heterogeneity. We observed that regardless of taxa and trophic level, individuals from populations within the biogeographic break showed higher phenotypic plasticity. Similarly, the spatial structure in neutral genetic markers for this diverse set of benthic species, which either spanned the transition zone or found the edge of their geographic ranges around it, hints at the presence of local adaptation. Our results suggest that evolutionary novel ecological interactions are taking place under environmental conditions that challenge species’ physiological limits. The species that span the transition zone are able to persist locally likely through a net influx of propagules; the strong selective pressure highlighted by plasticity patterns, together with our tentative evidence for local adaptation, suggests that the region may represent an area of special interest for future conservation efforts

Spatial patterns in phenotypic plasticity across a marine biogeographic transition zone: an eco-evolutionary driver?

Dissolved oxygen is a key environmental parameter for aquatic life. In two sets of experiments we evaluated the effect of long-term changes in the dissolved oxygen environment on the morpho-physiology and behaviour of the weakly electric fish Petrocephalus degeni. First, we captured fish from a severely hypoxic habitat in Uganda and acclimated them to normoxic conditions for up to 73 days while measuring respirometric and morpho-physiological traits in the field. In the second experiment, we used fish that had been kept under normoxic conditions for over two years in the laboratory. We assessed their hypoxia avoidance behaviour as well as physiological traits before and after 56 days of exposure to hypoxic conditions (15% air saturation). We found that gill size changed significantly in both experiments. Blood haemoglobin concentration was only affected during normoxia acclimation. Other traits, such as critical oxygen tension and hypoxia avoidance behaviour, were unaffected by the acclimation treatment. Our results suggest that P. degeni remain remarkably hypoxia tolerant throughout acclimation to different oxygen environments. Plasticity in respiratory traits that are directly associated with oxygen extraction and carrying capacity likely facilitates the homeostasis of higher-level traits linked to hypoxia tolerance, such as critical oxygen tension and hypoxia avoidance, by optimizing energetic trade-offs in different dissolved oxygen environments.

Plasticity in respiratory traits and stable hypoxia tolerance in a weakly electric fish exposed to long-term changes in dissolved oxygen environment

Drivers of large variation in observed fish growth, even under controlled conditions such as in aquaculture experiments, are not well understood. Size-based intraspecific competition is known to influence processes which lead to variation in both intake and growth. Yet, it is challenging to tease apart the effects of competitive interactions on fish growth from those of other factors because it remains difficult to repeatedly measure the relevant components of individual fish physiology that contribute to growth. We used an extensive longitudinal dataset of individual-level intake and growth measurements of 543 fish sampled from an aquaculture experiment to test the effects of relative body size as a proxy for competitive ability. This, in turn, was investigated as potential modulator of both individual feed intake and costs of living inferred from growth in a bioenergetic model. Using a Bayesian approach to integrate data and model, we estimated the mass-dependent scaling of intake and costs of living. Including relative size-effects on the allometric relationships for both intake and costs of living improved model fit and allowed us to reproduce a large part of the observed size variation. This implies that size-dependent competitive interactions are an important driver of size-at-age variation. Our results also indicate that growth depression in smaller than average fish is more significantly impacted by size-based competition effects on costs of living rather than on feed intake.

Size-based competition explains large variation in both intake and growth in aquaculture experiment

Cell division plane (CDP) orientation and cell growth directionality, determine tissue patterning and organ formation. A core component of CDP orientation is the preprophase microtubule band (PPB). It is known that PPB is physically associated with the plasma membrane (PM) requiring recruitment of scaffold proteins with affinity towards specific PM lipids and for proteins associated with microtubules. The mechanisms underlying the determination of CDP orientation are being vigorously studied. Yet, the specific identity and the role of PM lipids in the recruitment of scaffold proteins remain elusive. Sterols, a major lipid group forming nanodomains at the PM, play vital roles in cellular processes such as endocytosis, cell polarity and, cell expansion. Moreover, early studies on Arabidopsis sterol biosynthesis mutants have described severe developmental defects. However, no mechanism of implication of sterol biosynthesis deficiency in the determination of cell division has yet been proposed. Here, we have revisited the role of structural sterol biosynthesis on Arabidopsis vegetative growth and tissue patterning, as contrasted defects arising from compromised production of brassinosteroids, focusing on how CDP specific microtubule arrays are formed. Sterol biosynthesis mutants cpi1-1 and smt2smt3 showed defective vegetative phenotypes and disrupted histological pattern, as exemplified in the root. Aberrant mitosis with ectopic cell divisions. The smt2smt3 showed more severe phenotype than cpi1-1 indicating a possible role of structural phytosterols in the determination of CDP. Pharmacological treatments with sterol biosynthesis inhibitors phenocopied the sterol biosynthesis mutants. To conclude, cell division abnormalities are due to sterol biosynthesis pathway rather than brassinosteroids biosynthesis.

Impairment of sterol biosynthesis affects cell division and cell division plane orientation

Nitrogen is one of the most limiting nutrients for plant growth and is required in large amounts due to its role as a building block for essential molecules such as nucleic acids, chlorophyll, and proteins. As such, nitrogen application in the form of synthetic fertilizers is required to significantly increase crop yield and sustain a growing world population. We recently described the buzz root hairless mutant in Brachypodium distachyon. RNAseq analysis found an upregulation of nitrate transporters, NRT1.1A, NRT1.1B, and CIPK23 in the buzz mutant. In addition, RNAscope revealed partial colocalization of BUZZ mRNA and NRT1.1A in root hair tips. BUZZ also appears to mediate both primary and lateral root growth in a nitrate-dependent manner. Since evidence showing a direct link between root hairs and nitrogen acquisition is lacking in grasses, identifying additional components involved in nitrate acquisition as well as root hair growth can assist in efforts to improve NUE in cereal crops. We evaluated primary nitrate-responsive genes in the buzz mutant and found upregulation of NRT1.1, NRT2.1, TGA4, and NR1 in low nitrate conditions. We further determined nitrate uptake and nitrate use efficiency in buzz versus wild-type plants with normal root hairs. We also report the identification of five proteins that interact with BUZZ and functionally characterize them. Taken together, these data provide the foundational evidence of a heretofore unidentified genetic network that underlies nitrate responses in grasses and that also challenges the importance of root hairs in the uptake of this essential nutrient.

BUZZed on Nitrate: The effect of a root hairless mutant on nitrate acquisition in the model grass Brachypodium distachyon

The Arabidopsis genome contains genes encoding High Mobility Group (HMG) chromatin remodelers which function as transcription activators crucial for transcription of a plethora of genes. AtHMGB15, an ARID-HMG protein that harbors an AT rich interaction domain along with the classic HMG-Box DNA binding domain exhibits heightened expression primarily in flowers and pollen grains. The intricate process of male gametophyte development in flowering plants is regulated by jasmonic acid (JA) signaling. JA signalling initiates with the activation of MYC2 transcription factor, leading to the expression of numerous JA-responsive genes during stamen development, and pollen maturation. 

This study investigates the broader molecular analysis and biological relevance of transcriptional regulation of AtHMGB15 in orchestrating pollen development via the hormone pathway. Phenotypic characterization of athmgb15-4 mutant plants revealed delayed bolting, shorter siliques, and reduced seed set compared to the wildtype. Additionally, the mutation of AtHMGB15 resulted in defective pollen morphology, delayed pollen germination, aberrant pollen tube growth, and a higher percentage of non-viable pollen grains. In silico and molecular analysis validated the down-regulation of JA biosynthesis and signaling genes in the athmgb15-4 mutant. Quantitative analysis demonstrated that jasmonic acid and its derivatives were approximately tenfold lower in athmgb15-4 flowers. Exogenous application of methyl jasmonate could restore pollen morphology and germination alongside elevating the expression of previously down-regulated JA signaling genes, suggesting that the low jasmonate content in athmgb15-4 impaired JA signaling during pollen development. Furthermore, our study suggests that AtHMGB15 physically interacts with the MYC2 protein to form a transcription activation complex further promoting the transcription of two key JA signaling genes, namely MYB21 and MYB24, during stamen, and pollen development. 

We thereby propose the quintessential role of AtHMGB15 as a positive regulator of JA pathway, controlling the spatial, and temporal expression of key regulators involved in stamen and pollen development.

(Sachdev et. al., Plant Physiology 2024)


Deciphering AtHMGB15, an ARID-HMG Protein in Arabidopsis: Orchestrating the JA Pathway Through MYC2 Regulation in Pollen Development.

Parental age effects occur when offspring of older parents are of lower quality than offspring of younger parents. I will (1) present my research group’s evidence for parental age effects on offspring lifespan, reproduction, and fitness in aquatic plants in the genus Lemna (duckweeds); and (2) discuss the theoretical consequences for these effects on the evolution of senescence.

Parental age effects and offspring fitness in a clonally reproducing aquatic plant

Telomere length in early life is predictive of longevity in many species and reduced early life telomere length in offspring of older mothers has been linked to the reduced longevity frequently found in offspring of older breeders (the Lansing Effect). It is currently unknown whether such telomere reduction may persist beyond a single generation, as would be the case if germline transmission is involved. To test this, we performed a within-grandmother, multi-generational study using zebra finches. Our results indicate that shorter telomeres persist in offspring whose grandmothers were old at the time of their mother´s birth, despite their mother having been a young breeder. Our data highlight the need to look beyond a single generation to explain the causes of inter-individual variation in ageing rates and optimal reproductive schedules.

Negative effects of maternal age at breeding on offspring telomere length persist across twogenerations

In wild vertebrates, age has a strong influence on individual reproductive performance. Specifically, young parents are less likely to successfully rear offspring relative to older ones because of lower parental skills, lower parental investment or because of a progressive disappearance of lower-quality individuals at young ages (i.e., according to the constraint, restraint and selection hypotheses respectively). Such phenomenon has been extensively studied through reproductive success’ features. However, to better evaluate the influence of age on reproductive performance in species with high reproductive success, assessing also the quality of developmental conditions and offspring phenotype appears crucial. While it is practically difficult to follow an offspring during its entire life, several proxies of nestlings’ quality can be useful to assess the ability of young to survive and recruit into the population (i.e., body condition, corticosterone levels, and telomere length). By sampling chicks reared by known-aged mothers, we specifically investigated the influence of maternal age on offspring quality in two long-lived seabird species, the Black-browed Albatross (Thalassarche melanophrys) and the Snow Petrel (Pagodroma nivea). In both species, maternal age is correlated to proxies of offspring quality. More precisely, older individuals provide better parental cares to their offspring. In the light of the three age-related improvement of reproductive performance hypotheses, our results suggest that maternal age can affect offspring phenotype with potential long-term consequences.

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Soluble adenylyl cyclase regulates intracellular pH homeostasis of calcifying cells in the sea urchin larva.

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Rathletes do not give you wings: How paternal exercise, caffeine, and/or alcohol affects offspring pathophysiology and behaviour following repetitive mild traumatic brain injury (RmTBI)

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Next from SEB Conference 2024

Soluble adenylyl cyclase regulates intracellular pH homeostasis of calcifying cells in the sea urchin larva.

Similar lecture

Rathletes do not give you wings: How paternal exercise, caffeine, and/or alcohol affects offspring pathophysiology and behaviour following repetitive mild traumatic brain injury (RmTBI)

Stay up to date with the latest Underline news!

PRESENTATIONS

CONFERENCES

COMPANY

RESOURCES

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