Swimming Performance Of Larvae Research Articles

Ammonium effects on oxidative stress, telomere length, and locomotion across life stages of an anuran from habitats with contrasting land-use histories

Understanding the mechanistic implications behind wildlife responses to global changes is a central topic in eco-evolutionary research. In particular, anthropic pollution is known to impact wild populations across the globe, which may have even stronger consequences for species with complex life cycles. Among vertebrates, amphibians represent a paradigmatic example of metamorphosis, and their characteristics make them highly vulnerable to pollution. Here, we tested for differences in the redox status, telomere length, and locomotor performance across life stages of green frogs (Pelophylax perezi) from agrosystem and natural habitats, both constitutively and in response to an experimental ammonium exposure (10 mg/L). We found that larvae from the agrosystem constitutively showed an enhanced redox status (better antioxidant balance against H2O2, lower lipid peroxidation) but shorter telomeres as compared to larvae from the natural environment. The larval redox response to ammonium was, overall, similar in both habitats. In contrast, after metamorphosis, the redox status of individuals from the natural habitat seemed to cope better with ammonium exposure (denoted by lower lipid peroxidation), and differences between habitats in telomere length were no longer present. Intriguingly, while the swimming performance of larvae did not correlate with individual's physiology, metamorphs with lower glutathione reductase activity and longer telomeres had a better jumping performance. This may suggest that locomotor performance is both traded off with the production of reactive oxygen species and potentiated directly by longer telomeres or indirectly by the mechanisms that buffer their shortening. Overall, our study suggests that contrasting land-use histories can drive divergence in physiological pathways linked to individual health and lifespan. Since this pattern was life-stage dependent, divergent habitat conditions can have contrasting implications across the ontogenetic development of species with complex life cycles.

Exposure of gametes to aged nano-sized plastic particles during fertilization can influence early larval development in the European whitefish (Coregonus lavaretus)

Plastic pollution has been a growing environmental concern for decades, increasingly affecting both marine and freshwater ecosystems worldwide. Nano-sized plastic particles (NPs) potentially have various toxicological impacts on aquatic organisms and the ecosystem; however, less is known about their possible adverse effects on the reproductive biology and offspring traits of fishes. The present study investigated whether an acute exposure of gametes to aged NPs during fertilization affects offspring early mortality, hatching time, body size at hatching or swimming performance of larvae in a common freshwater fish, the European whitefish (Coregonus lavaretus). Using a replicated full-factorial breeding design, we fertilized the eggs of seven females with the milt of seven males both under exposure medium containing aged 270 nm polystyrene NPs and under control medium. In comparison with the control group, exposure of gametes to NPs increased larval body length slightly but significantly, whereas the embryo mortality, hatching time, and larval swimming performance were not affected. Maternal identity affected significantly all the studied offspring traits while paternal identity only affected the offspring length. Our results suggest that the studied acute exposure of gametes to aged NPs might have interfered normal embryonic development by affecting larval size, but this did not seemingly compromise offspring performance.

Effects of bisphenol A or diethyl phthalate on cartilage development and the swimming behavior of zebrafish (Danio rerio) through maternal exposure

Waterborne bisphenol A (BPA) and diethyl phthalate (DEP) are endocrine disruptive chemicals that impact the reproductive system of fish. The present study checks the effectiveness of the reproductive capacity on zebrafish after BPA and DEP exposure, and consequently investigates its effect on their development and the swimming behavior of its offspring. The exposure of BPA and DEP to zebrafish reveals that the levels of ovarian 17β-estradiol (E2) and relative mRNA expression (RRE) ratios (Treatment/Control) of hepatic vitellogenin (vtg1) could be induced and decreased. Liver RRE levels in estrogen receptors (ERs) are also affected. Among the ERs, esr2a significantly increased upon BPA exposure, and esr1 and esr2b decreased upon DEP exposure. In addition, the ceratohyal cartilage (CH) angle of larvae whose mothers were exposed to BPA (F-BPA) was significantly bigger, but the CH angle of larvae whose mothers were exposed to DEP (F-DEP) was significantly smaller than the control. The swimming performance of larvae from F-DEP was more compromised than the control, but the situation did not appear in the larvae from the F-BPA group. The success rate of larvae hatching from F-BPA and F-DEP was lower than control group. Moreover, the successful rate of female spawns was higher in the control group compared to the treatment groups exposed to BPA and DEP. We suggested that both maternal BPA and DEP disrupt E2 levels, and influence the CH development of larvae, resulting in a decrease in successful hatching. Only the swimming behavior of larvae from maternal DEP was disrupted.

Linking genomic responses of gonads with reproductive impairment in marine medaka (Oryzias melastigma) exposed chronically to the chemopreventive and antifouling agent, 3,3′-diindolylmethane (DIM)

3,3′-Diindolylmethane (DIM) has been promoted as an effective chemopreventive and antifouling additive. However, the concurrent risks or side effects of DIM are not fully understood, especially on tissues responsive to estrogen. Therefore, this study employed marine medaka (Oryzias melastigma) as a test model to evaluate relative safety and explore mechanisms of toxic action of DIM on development and function of gonad after chronic (28days) aqueous exposure to relatively low doses (0μg/L or 8.5μg/L). Integration of comprehensive toxicogenomic analysis at the transcriptome and proteome levels with apical endpoints, such as production of eggs and swimming performance of larvae, elucidated the molecular linkage in gonad from bottom up along the reproductive adverse outcome pathway. A series of sequential changes at the transcript and protein levels were linked to lesser fecundity and viability of larvae exposed to DIM. Anomalous production of vitellogenin (VTG) and eggshell proteins in testis confirmed the estrogenic potency of DIM. In the ovary, although storage of VTG was greater, lesser expressions of cathepsin enzymes blocked cleavage and incorporation of VTG into oocytes as yolk, which acted together with lower eggshell proteins to inhibit maturation of primary oocyte and thus contributed to impairment of fecundity. Overall, this study demonstrated that exposure to DIM impaired reproductive fitness. Diverse molecular initiating changes in gonads were linked to apical endpoints that could be used in assessment of risks posed by DIM on gametogenesis. In combination with chemical stability and potent endocrine disruption, the results of this study can inform decisions about the use of DIM either as chemopreventive or antifouling agent.

THE EVOLUTION OF LARVAL MORPHOLOGY AND SWIMMING PERFORMANCE IN ASCIDIANS

The complexity of organismal function challenges our ability to understand the evolution of animal locomotion. To meet this challenge, we used a combination of biomechanics, phylogenetic comparative analyses, and theoretical morphology to examine evolutionary changes in body shape and how those changes affected swimming performance in ascidian larvae. Results of phylogenetic comparative analyses suggest that coloniality evolved at least three times among ascidians and that colonial species have a convergent larval morphology characterized by a large trunk volume and shorter tail length in proportion to the trunk. To explore the functional significance of this evolutionary change, we first verified the accuracy of a mathematical model of swimming biomechanics in a solitary (C. intestinalis) and a colonial (D. occidentalis) species and then ran numerous simulations of the model that varied in tail length and trunk volume. The results of these simulations were used to construct landscapes of speed and cost of transport predictions within a trunk volume/tail length morphospace. Our results suggest that the reduction of proportionate tail length in colonial species resulted in improved energetic economy of swimming. The increase in the size of larvae with the origin of coloniality facilitated faster swimming with negligible energetic cost, but may have required a reduction in adult fecundity. Therefore, the evolution of ascidians appears to be influenced by a trade-off between the fecundity of the adult stage and the swimming performance of larvae.