France

SEB Annual Conference 2022

Plants Actin’ Up – Automatic Cytoskeleton Extraction in Arabidopsis

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

The site will be open for registered participants closer to the event.

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

Berghia stephanieae is a small nudibranch of the aeolid family, known to feed voraciously on the anemone Aiptasia pallida, a common pest in tropical aquaria. Berghia is sold in the aquarium trade for anemone density control. Though well documented in the aquarium context, studies on Berghia-Aipatsia interactions in the natural environment are more scarce. Being a specialised predator (as are most nudibranchs) that feeds exclusively on A. pallida, it is unclear how both species can coexist in the natural environment without B. stephanieae causing local extirpation of its prey. Building on the discovery of kleptopredation in 2017 in the aeolid nudibranch Cratena peregrina, the current research investigates the possibility of this mechanism being used by other nudibranch species, here B. stephanieae. C. peregrina is a highly specialised predator known to feed exclusively on hydroid E. racemosum polyp, yet half of their diet was found to consist of planktonic prey acquired through kleptopredation. The current research investigates the feeding strategy of B. stephanieae, and the possibility of kleptopredation. B. stephanieae were reared and fed in the laboratory with either kleptopredation treatment (recently-fed anemones) or control diet treatment (unfed anemones). Their physiology was studied over time under each treatment conditions, to assess the possible benefits of kleptopredation on the energy budget. Preliminary results suggest kleptopredation is exhibited by Berghia stephanieae. Growth, spawning, and respiration measurements show that this feeding strategy could provide energetic benefit to the nudibranch predator by allowing more energy to be invested in growth and reproduction. 




Physiology and feeding strategies of Berghia stephanieae (Nudibranchia: Aeolidiodea)

The 65 million year acoustic arms race between moths and bats has lead to the evolution of numerous different defence strategies amongst moths against bat echolocation.  Some moths have evolved passive defences such as ultrasound absorbing scales, which diminish the strength of a moth generated echo returning to a bat.  The scales work by resonant mechanisms and are much smaller than the wavelength of the sound which they absorb. This unique architecture opens avenues for bioinspired sound insulation solution that are much smaller than current technical sound absorbers. Previous works have looked at sound absorption by moth scales in free space, but to determine their effectiveness as a sound insulating solution for buildings, their performance must be measured when resting on a hard substrate. Here, we measure the potential for moth wings to act as a sound absorbing surface coating for acoustically reflective substrates. Moth wings were found to be efficient sound absorbers, reducing reflection from an acoustically hard surface by up to 87% despite a thickness to wavelength ratio of up to 1/50 at the lowest frequency tested (20 kHz). Remarkably, after removal of the scales from the dorsal surface the wing’s orientation on the surface changed its absorptive performance: absorption remains high when the bald wing membrane faces the sound but breaks down almost completely in the reverse orientation. The finding that moth wings can act as a sound absorbing surface opens the door to the creation of biomimetic light-weight noise mitigation materials.

Towards moth wing inspired sound absorbing materials

The increasing frequency and intensity of marine heatwaves (MHW) and simultaneous water deoxygenation (i.e., hypoxia) resulting from anthropogenic climate change is increasingly affecting marine organisms worldwide. These stressors occur throughout the year, and marine organisms may be differentially vulnerable to these events across seasons. While most climate change projections highlight summer maximum temperatures as the greatest threat to coral reef organisms, this prediction has never been tested. After characterizing local MHWs in Kāneʻohe Bay, HI, we compared the capacity of representative Hawaiian reef fish of commercial importance—the convict tang (Acanthurus triostegus; manini) —to tolerate the combined effects of acute thermal stress and reduced oxygen availability that occur during MHWs between seasons. While marine heatwaves did not significantly differ in heating rate, duration, or warming anomaly (i.e., temperature increase above the seasonally varying threshold) between summer and winter, the metabolic response of A. triostegus significantly varied between seasons. We found winter MHWs had a stronger effect on thermal sensitivity of standard and maximum metabolic rate with higher Q10 coefficients (i.e., an indicator of thermal stress) during winter MHWs. Hypoxia tolerance did not significantly vary between seasons, but winter MHWs caused a greater reduction in hypoxia tolerance compared to summer, despite the greater absolute temperatures of summer. We discuss the importance of clarifying climate change impacts year-round.

Seasonal variability in metabolic resilience to environmental stress in a Hawaiian reef fish

Cold acclimation induces cardiac remodelling in rainbow trout. This remodeling can include changes in contractile function, cardiac hypertrophy as well as an increase in collagen content. To understand how collagen is regulated in the trout heart we have been studying the function of cultured trout cardiac fibroblasts, the cells responsible for collagen turnover. We have previously found that exposure of these cells to cyclical stretch and transforming growth factor beta 1 (TGF-β1) activate cellular signalling pathways involved in collagen deposition and increase collagen deposition. In the current study, we have examined the influence of different levels of cyclical stretch, testosterone, and angiotensin II (ANG II), on the cell signalling pathways that regulate collagen deposition. We also examined how low temperature and TGF-β1 affected these responses. We found that the effect of cyclical stretch on collagen related signalling pathways is frequency and magnitude dependent. In addition, testosterone treatment led to changes in gene expression that would support an increase in collagen deposition regardless of temperature. This includes changes in the expression of the gene transcripts for matrix metalloproteinase-9, collagen type 1 alpha, and tissue inhibitor of metalloproteinases 2. We also found that 1 µM of ANG II had no effect on collagen-associated gene expression. Our results also suggest that the effect of TGF-β1 on collagen deposition is temperature dependent.  The results of this work provide mechanistic insight into the regulation of collagen deposition in the trout heart and how this is affected by temperature change. This research is funded by NSERC. 

The influence of environmental and endocrine factors on collagen regulatory pathways in rainbow trout (Oncorhynchus mykiss) cardiac fibroblasts

The epidermis serves as a multifunctional interface between plants and their environment. 
The leaf surfaces of carnivorous plants such as the Nepenthes pitcher rim (peristome) are highly specialised. The structure of the peristome is unique, holding a hierarchical pattern of radial ridges, grooves, and overlapping steps, that render it highly wettable and slippery to insects when wet. Virtually nothing is known about how the peristome's characteristic microtopography forms inside the hollow, developing pitcher bud. We used SEM imaging to document this process for the first time. We found that a sequence of distinct epidermal patterning events (cell organisation, conical cell formation, papillate cell outgrowth, and cell elongation) governs peristome development. All of these individual processes are common and conserved in leaf epidermal patterning across plant lineages. We hypothesise that Nepenthes co-opted these processes for peristome development and combined them in a novel way. In order to probe the genetic underpinnings of the sequential epidermal patterning events, we identified external morphological markers on the growing pitcher bud and linked these to a timeline of internal peristome development. This will allow us to target specific stages of surface patterning with confidence, which is crucial for investigating gene expression patterns and gene function during development. 













Nepenthes pitcher plants recombine common patterning processes to create a complex hierarchical epidermis structure

Food waste is a global issue with 1/3 of all food lost or wasted annually. Tomato is a culturally important fruit that provides nutrition to a global market but is highly perishable and requires carefully controlled storage and transportation to maintain shelf life. Losses occur throughout the entire supply chain as often the symptoms of spoilage are detected too late for effective repurposing. There are existing methods that are used in a commercial environment for detecting spoilage, however, these methods are often slow, destructive, and expensive. It is important that a non-destructive, high-throughput and cheap technology becomes readily available that can used throughout the supply chain to detect spoilage biomarkers for effective repurposing of produce. This study investigates the use of attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy as a rapid, quantitative method for detecting decay in surface tissue of tomato fruit. Spectra was analysed using chemometric multivariate analysis of the fingerprint region (400 cm-1 to 1500 cm-1). In a time-series from harvest to spoilage, we identified differences between the time points in the series demonstrating the molecular changes in the fruit surface through the ripening and decaying period. Distinct chemical peaks were detected which represent potential biomarkers for spoilage and were associated with specific time points. Notable fruit properties associated with these peaks include the changes in levels of phenolic compounds, cell wall polysaccharide modifications including pectin and cellulose. ATR-FTIR provides a low-cost method for in vivo detection of spoilage biomarkers and biochemical changes. 

Effective detection of spoilage biomarkers in tomatoes 

Understanding the mechanisms determining these limits is, therefore, essential in our general understanding of thermal tolerance of ectotherms. It has been put forth that oxygen limits cardiac performance at high temperatures, although this has rarely been explicitly or thoroughly tested. It has also been suggested that hyperkalemia may negatively impact cardiac function under elevated temperatures. We hypothesized that low environmental oxygen and elevated blood [K+] would reduce the upper thermal limits of the heart in a marine teleost (Girella nigricans). Using the Arrhenius Breakpoint Temperature Test, we assessed fish (n=12 per treatment) under hyperoxic (200% air saturation), normoxic (100% air saturation), and hypoxic (20% air saturation) conditions under a range of plasma [K+]. We also measured ventricle lactate content and venous blood oxygen pressure (PO2) to determine if there were common critical points in these metrics driving cardiac collapse. We found significant differences in cardiac upper thermal limits (Arrhenius breakpoint temperature [TABT], peak maximum heart rate (peak fHmax], temperature of peak heart rate [Tpeak], and temperature at which the heart becomes arrhythmic [TARR]) in fish exposed to hypoxia during the trial compared to those exposed to normoxia or hyperoxia. We also found significantly higher ventricular lactate content in fish exposed to hypoxia. Elevated [K+] may be correlated with decreases in TABT, but there were no other significant correlations. These results suggest that oxygen limitation can drive cardiac collapse at high temperatures. 

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Plants Actin’ Up – Automatic Cytoskeleton Extraction in Arabidopsis

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Physiology and feeding strategies of Berghia stephanieae (Nudibranchia: Aeolidiodea)

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