Biology subjects

Boonekamp, J.

Publications and source records attributed to Boonekamp, J..

4 recordsLinked to original sources

bioRxiv2025

The impact of microplastics on the mice gut microbiome: a meta-analysis

BackgroundMicroplastics are nearly ubiquitous in the natural environment. There is increasing awareness of the ingestion of microplastics in a wide range of wild animals and humans, but their health and fitness impacts remain poorly understood. Mounting evidence suggests that microplastics could accumulate in the gut, affecting the microbiome and hindering its function. This may constitute a direct pathway through which exposure to microplastics could affect health and disease. However, prior studies on the effects of microplastic exposure on the microbiome show contrasting findings raising the question whether microplastics truly affect the microbiome. Here, we performed the first meta-analysis on the effects of dietary microplastic exposure on the gut microbiome of mice. ResultsOverall, we found support for a significant impact of microplastic exposure on the relative abundance of gut bacteria. More in-depth analysis revealed microplastic exposure significantly increased the relative abundance of Bacillota and Pseudomonadota. In the gut microbiome, Bacillota is associated with carbohydrate metabolism and Pseudomonadota is associated with facultative anaerobes, thus these changes may have functional consequences. ConclusionsOur findings highlight the importance of distinguishing among differing bacterial phyla when assessing the impacts of microplastics on the gut microbiome as the direction and size of the impact varies by phyla.

microbiology↗

bioRxiv2025

Questioning the utility of oxidative stress measurements as biomarkers of physiological condition and fitness

Markers of oxidative stress are widely used as indicators of physiological state, but their utility for ecological and evolutionary inference remains uncertain due to high intraindividual variation masking associations with environmental conditions, fitness, and other physiological indicators such as telomere length. Although numerous longitudinal studies exist, individual repeatability of oxidative stress measurements is rarely reported explicitly. Here, we present the first meta-analysis assessing individual repeatability of oxidative stress markers, comprising 123 repeatability estimates from 22 studies. Overall, oxidative stress markers exhibited low repeatability on average (Intraclass correlation = 0.164), although repeatability estimates were highly heterogenous across biomarkers, study systems, and ecological contexts. Repeatability was generally low across taxa, sexes, study designs, and environments, although some markers, particularly lipid peroxidation quantified with HPLC, exhibited moderate repeatability in specific contexts. To illustrate the statistical consequences of low repeatability, we used heuristic simulations examining associations between oxidative stress and telomere length under different biological scenarios. These simulations demonstrate how low repeatability substantially reduces statistical power, but this is somewhat mitigated by taking repeated measurements. More broadly, our findings highlight the value of greater cross-disciplinary dialogue, as ecological and biomedical studies often use oxidative stress biomarkers in different ways and may benefit from shared perspectives.

physiology↗

bioRxiv2023

Environmental constraints can explain clutch size differences between urban and forest blue tits (Cyanistes caeruleus): insights from an egg removal experiment

Urban environments present novel ecological challenges to wild species. Understanding whether species responses to urban living are adaptive or maladaptive is critical to predicting the impacts of urbanisation on biodiversity. In birds, urban populations generally exhibit reduced reproductive investment (clutch size) compared to forest populations. However, whether smaller clutches are adaptive, or a result of environmental constraints is unclear. Here, to investigate these two hypotheses, we quantified the ability of urban and forest blue tits (Cyanistes caeruleus) to lay new eggs upon egg removal. Consistent with the constraint hypothesis, our results suggest that urban females do not lay new eggs, at least to the same extent as forest birds. Meanwhile, forest birds laid approximately two additional eggs. As urban blue tits did not lay replacement eggs, our experiment resulted in a brood reduction and nestlings from urban experimental nests had higher survival than those from urban control nests, suggesting that females may be misjudging urban habitat quality and produce a clutch too large to be sustained. Taken together, our results suggest that urban females may experience constraints that limit egg formation and/or exacerbate the trade-off between female survival and egg production. This has important implications for urban green space management.

ecology↗

bioRxiv2020

Telomere length is highly heritable and independent of growth rate manipulated by temperature in field crickets

Many organisms are capable of growing faster than they do. Restrained growth rate has functionally been explained by negative effects on lifespan of accelerated growth. However, the underlying mechanisms remain elusive. Telomere attrition has been proposed as a causal agent and has been studied in endothermic vertebrates. We established that telomeres exist as chromosomal-ends in a model insect, the field cricket, using terminal restriction fragment and Bal 31 methods. Telomeres comprised TTAGGn repeats of 38kb on average, more than four times longer than the telomeres of human infants. Bal 31 assays confirmed that telomeric repeats were located at the chromosome-ends. We tested whether rapid growth is achieved at the expense of telomere length by comparing crickets reared at 23°C with their siblings reared at 28°C, which grew three times faster. Surprisingly, neither temperature treatment nor age affected average telomere length. Concomitantly, the broad sense heritability of telomere length was remarkably high at ~100%. Despite high heritability, the evolvability (a mean standardized measure of genetic variance) was low relative to that of body mass. We discuss the different interpretations of these scaling methods in the context of telomere evolution. It is clear that some important features of vertebrate telomere biology are evident in an insect species dating back to the Triassic, but also that there are some striking differences. The apparent lack of an effect of growth rate and the total number of cell divisions on telomere length is puzzling, suggesting that telomere length could be actively maintained during the growth phase. Whether such maintenance of telomere length is adaptive remains elusive and requires further study investigating the links with fitness in the wild.Competing Interest StatementThe authors have declared no competing interest.View Full Text

zoology↗