Czechia

The project aimed to investigate the influence of geography,
evolutionary history, and host genetics on the skin microbiome diversity
of the moor frog (Rana arvalis), a widespread amphibian species. By
examining 12 populations from two geographical clusters, we explored
the association between bacterial diversity and composition and the
major histocompatibility complex class II exon 2 diversity. Results
revealed significant variations in MHC alleles/supertypes and genetic
diversity based on geography and evolutionary history. While bacterial
alpha diversity remained consistent across clusters, it correlated
positively with expected MHC heterozygosity and negatively with
MHC nucleotide diversity. Moreover, bacterial community composition
exhibited significant differences between clusters and specific MHC
alleles/supertypes. These findings underscore the impact of historical
demographic events on hologenomic variation and provide insights
into how immunogenetic host variability and microbial diversity may
collectively influence host fitness and disease susceptibility, ultimately
affecting population persistence.

SEB Conference Prague 2024

Association between the skin microbiome and MHC class II diversity in an amphibian

16s microbiome

rana arvalis

technical paper

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Organisms exhibit reversible physiological adjustments as a response to rapidly changing environments. Yet such plasticity of the phenotype is gradual and may lag behind environmental fluctuations, thereby affecting long‐term average performance of the organisms. By supplying energy and essential compounds for optimal tissue building, food determines the range of possible phenotypic changes and potentially the rate at which they occur. Here, we assess how differences in the dietary supply of essential lipids modulate the phenotypic plasticity of an ectotherm facing thermal fluctuations. We use three phytoplankton strains to create a gradient of polyunsaturated fatty acid and sterol supply for Daphnia magna under constant and fluctuating temperatures. We used three different fluctuation periodicities to unravel the temporal dynamics of gradual plasticity and its long‐term consequences for D. magna performance measured as juvenile somatic growth rate. In agreement with gradual plasticity theory, we show that in D. magna, fluctuation periodicity determines the differential between observed growth rates and those expected from constant conditions. Most importantly, we show that diet modulates both the size and the direction of the growth rate differential. Overall, we demonstrate that the nutritional context is essential for predicting ectotherm consumers' performance in fluctuating thermal environments.

Food quality shapes ectotherm gradual phenotypic plasticity

The host gut microbiome functions in digestion and immune defense, but additionally influences cognitive behavior. Habitat and diet are strong influencers in shaping the gut microbiome. However, among closely related species, phylogenetic relatedness is a strong predictor of gut microbiome community composition. Although phylogeny is a strong predictor, the impact hybridization has on the gut microbiome is poorly known. To explore this, we sampled feces from nestlings across a hybrid zone transect for black-capped (Poecile atricapillus) and Carolina chickadees (Poecile carolinensis) during the 2021 and 2022 breeding seasons. These nestlings were brought back to the Lehigh University Animal Facility and raised to adulthood under common conditions for cognitive testing. Fecal samples were taken at multiple time points and used to characterize the gut microbiome community composition. To do this, we extracted microbial DNA and sequenced the V3-V4 region of the 16S rRNA gene. Using amplicon sequence variants (ASVs), we compared the abundance and diversity of bacterial taxa across ancestry groups and at different time points after experiencing common conditions. Being raised under common conditions led to a decreased alpha diversity for parental species, but not for hybrids. After standardizing environmental conditions, differences between ancestry groups in abundance of specific gut phyla and specific ASVs suggests that genetic variation also plays a significant role in gut microbial composition. Alpha diversity and abundance of individual ASVs seemed to correlate with cognitive performance as well. Assessing the factors that influence gut microbiome diversity in two closely related sister species and their hybrids helps us to better understand the various factors that shape host-microbiome communities.

Microbiome Diversity and Cognition in Hybridizing Chickadees

The transition from water to air, or terrestrialization, is a key event in the evolution of many marine organisms to exploit new ecological niches for food, stress buffers, and to access higher and temperature-independent air oxygen concentrations. Microorganisms are pivotal for host adaptation, however their contribution to overcoming the challenges posed by the lifestyle changes from water to land is not well understood. In this study, we examined how microbial associations with a key multifunctional organ, the gill, is involved in the intertidal adaptation of mangrove dwelling fiddler crabs, which are dual-breathing organisms. Electron microscopy revealed a rod-shaped bacterial layer tightly connected to the gill lamellae of five crab species sampled across a latitudinal gradient spanning the central Red Sea to the southern Indian Ocean. The gill bacterial community diversity assessed with 16S rRNA gene amplicon sequencing was consistently low across crab species, and the same actinobacterial group, namely Ilumatobacter, was dominant regardless of the geographic location of the host. Using metagenomics and metatranscriptomics, these members of actinobacteria were found to potentially be able to convert ammonia to amino acids and could help eliminate the toxic sulphur compounds and carbon monoxide to which crabs are constantly exposed. These results indicate that gill bacteria can play a role in the adaptation of animals in dynamic intertidal ecosystems. Hence, this relationship is likely to be important in the ecological and evolutionary processes of the transition from water to air and deserves further attention, including the ontogenetic onset of this association.

The role of gill-associated bacteria in the adaptation to terrestrial environments of mangrove crabs

Differences in growth rate and metabolism between individuals can determine competitive social dynamics as well as survival during vulnerable life stages. While this inter-individual variability has received growing attention, variability within individuals can also be substantial but has rarely been studied. Here, we used the ecologically and culturally important estuarine fish Galaxias maculatus to understand inter- and intra-individual variability in metabolism and determine their relative contributions to growth.

Specifically, we collected repeated measurements of metabolic and growth performance across 6 months to gauge inter- and intra-individual variability in both metrics for a wild-caught population of 160 G. maculatus. Groups of fish were fed to satiation and housed in tanks where each fish had a unique colored subcutaneous elastomer tag. Fish were initially measured for active, routine, and standard metabolic rates at 18℃ before being randomly assigned to an acclimation group at either 18℃ (benign summer temperature) or 23℃ (challenging summer temperature). We tracked each individual’s growth and collected a further five metabolic measurements per fish (~1 per month). 

Our results showed negligible correlation between specific growth rate and both standard and routine metabolic rates. Inter- and intra-individual variability were similar for both standard and routine metabolic rates (mass-standardized), including between temperature treatments. These findings provide some of the strongest evidence that the metabolic phenotype of an individual can change across time, matching the extent of the variability within a population. 


Intra- and inter-individual variability in metabolism drives growth performance of a temperate estuarine fish

Variation in animal behaviour has recently gained traction in understanding variation within physiological traits. Integrating animal behaviour may be particularly important for measuring metabolism as oxygen demand is sensitive to the behavioural state of the individual. For example, a fish exposed to a novel environment may exhibit individual differences in metabolic oxygen demand as a consequence of behavioural responses, such as activity and exploration related to anxiety in an unfamiliar context. On this background, we sought to explore variation in routine metabolism (RMR) as a consequence of novelty to the testing chamber and substrate color – with black representing a low anxiety state and white a high anxiety state – using a repeated measures experimental design to track differences in individual traits across treatments. Finally, as shoaling is thought to reduce predation risk and therefore may influence stress-related responses, we tested a subset of individuals in a third iteration of respirometry with a size-matched conspecific. Contrary to our predictions, we found no difference in RMR with black vs. white substrate; whereas, RMR was significantly higher during the second iteration of respirometry, independent of substrate color. Interestingly, the total oxygen consumption in our paired fish tests was not significantly different from the mean RMR in the initial run, potentially indicating a mollifying social effect. Behavioural data suggests differences in activity/exploration that complement metabolic patterns. Our data indicates individual variation in behaviour, especially in response to novelty, and its impacts on the stability of metabolic measurements.

Patterns of individual variation in metabolism and behavioural responses in the sheepshead minnow (Cyprinodon variegatus)

Risk assessments have identified prey limitation as one of the strongest risk factors for juvenile salmon migration survival under climate change. In British Columbia, Canada, juvenile Chinook salmon (Oncorhynchus tshawytscha) may experience prolonged periods of food deprivation during their marine entry and first marine winter. In this study we conducted a lab-based food deprivation and refeeding experiment to assess the physiological consequences of starvation and
identify transcriptional responses to develop mRNA-based biomarkers for food limitation in the gill of juvenile Chinook salmon. Throughout the experiment, fish were held at both summer (16oC; marine entry) and winter (8oC; overwintering) temperatures and were sampled at least every 2 weeks collecting physiological data (condition factor, hepatosomatic index, morphometrics) as well as liver and gill tissue for RNA-sequencing. As expected, both food-deprivation treatments demonstrated significant differences from their fed counterparts with decreases in condition factor and hepatosomatic index with 14 to 28 days, respectively. The 16oC acclimation treatment was the first to reach a starvation endpoint (10% mortality) by 35 days,
with the 8oC treatment persisting until 56 days (20% reduced condition factor). During refeeding, condition factor returned rapidly in both acclimation treatments, 9-12 days post feed introduction. Further, hepatosomatic index recovered within 3 days and increased up to 2.5-fold when compared to unfasted counterparts by days 12-21 of the refeeding process. Conserved transcriptional responses between 8oC and 16oC treatments will be discussed in the context ofpathways modified by starvation, and candidate biomarkers for nonlethal screening in wild
juvenile Chinook salmon.

 Food deprivation, physiological impacts, and associated transcriptional responses in juvenile Chinook salmon

AI provides a fast and efficient way to generate textual outputs, produce images, analyse core learning, and evaluate biological data. This is driving a transformation in education, with consideration needed around current assessment practices as tools such as ChatGPT become more prevalent. In this talk, we will explore some of the pedagogic approaches and assessment strategies that have been successfully developed that allow for the incorporation of AI into the assessment. When used correctly, and ethically, AI can be a valuable learning aid for students and an effective facilitative tool for educators.

Generative AI: the power and the peril in Biosciences education

‘Now we’re going to work in groups’ is often a phrase which causes a feeling of dread and anxiety in students, but it doesn’t need to. There is a plethora of advantages to structured group work, including the skills that students can develop, but also for authenticity in learning and assessment for learning. Teaching in groups can facilitate peer-peer feedback and subsequently independence from lecturers, leading ultimately to more independent and collegial graduates. Students supporting one another as the first port of call enhances efficiency for lecturers. Group work can also help to reduce the costs of the hidden curriculum: students who haven’t developed those skills can learn them from peers.
The advantages are also numerous for lecturers. In large modules, marking can be a significant workload and due to large volumes of marking, it can be impossible to provide truly meaningful feedback, without losing consistency by splitting the marking between staff. Incorporating group submissions means that there are fewer items to mark and therefore, feedback can be much more in depth and useful. The reduced number of submissions has enabled the design of an assessment which is significantly more authentic, efficiently addresses learning outcomes, and provides a learning experience for the students.
This talk will illustrate how I have introduced groupwork to be a significant part of my large first year module in a way that the students have enjoyed and benefitted from and the vital considerations to ensure success when designing similar schemes of work.

Working together: The use of groupwork to enhance authenticity in assessment and feedback.

Characterization of differences in N assimilation and deficiency responses in C3 and C4 Cleome species
The evolution of C4 photosynthesis led to increased carbon assimilation rates and plant growth. In contrast to C3 plants, which use Rubisco for primary CO2 fixation in all photosynthetic cell types, in C4 plants carbon is initially fixed in mesophyll cells (MCs) by PEP carboxylase (PEPC). Subsequent decarboxylation of the resulting C4 acid takes place in the bundle sheath cells (BSCs). This increases the local CO2 concentration around Rubisco, which minimizes its oxygenation reaction reducing photorespiration and thereby improving photosynthetic efficiency. Similarly, in most C4 plants the reduction of nitrate and nitrite is restricted to MCs, while the further assimilation of reduced nitrogen into the amino acids glutamate and glutamine mainly takes place in the BSCs. Changes in the expression pattern of glycine decarboxylase (GDC) lead to the restriction of photorespiration and therefore serine production to BSCs. Balancing of metabolic routes is therefore necessary to maintain homeostasis of not only carbon but also nitrogen (N) metabolism. These differences in N requirements of the two photosynthetic mechanisms pose the question of how N assimilation pathways differ between C3 and C4 species and whether these changes are a consequence or prerequisite of C4 evolution. Characterization of mineral nutrition traits revealed clear differences in the N metabolism of C3 and C4 Cleome species under N deficiency conditions, indicating a higher N deficiency tolerance in the C4 species. The addition of NH4+ was shown to offset the reduction of biomass and photosynthetic efficiency in the C3 but not the C4 Cleome species.


Characterization of differences in N assimilation and deficiency responses in C3 and C4Cleome species

Cowpea (Vigna unguiculata) is an essential crop providing a substantial source of protein and ensuring food security for Sub-Saharan Africa. However, with the unpredictable fluctuations of temperature caused by climate change, heat waves are becoming more frequent threatening cowpea yields. Rubisco, the central protein for carbon assimilation is thermostable, however its chaperone Rubisco activase (Rca) is temperature sensitive. Cowpea has four Rca isoforms: 1β, 8α, 10α and 10β. In this study we investigated the effect of a heat wave on Rca isoform levels in cowpea monitoring in parallel changes in growth traits and Rubisco activity. Cowpea plants cultivar IT97K-499-35 were grown at 28/18oC day/night for 14 days and then exposed to a 5-day heat wave at 38/28oC day/night. The heat wave caused changes in leaf shape, a decrease in Rubisco activity, changes in overall gene expression as well as in the relative levels of the different Rca isoforms. In vitro characterisation of the temperature response of the cowpea Rca isoforms showed differences in temperature optima for activity that could be exploited to enhance the thermal tolerance of cowpea.

Association between the skin microbiome and MHC class II diversity in an amphibian

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Association between the skin microbiome and MHC class II diversity in an amphibian

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Next from SEB Conference Prague 2024

Food quality shapes ectotherm gradual phenotypic plasticity

Stay up to date with the latest Underline news!

PRESENTATIONS

CONFERENCES

COMPANY

RESOURCES

Downloads