Assessment of sperm DNA integrity within the Palaemon longirostris (H. ) population of the Seine estuary

Advancing environmental monitoring across the water continuum combining biomarker analysis in multiple sentinel species: A case study in the Seine-Normandie Basin (France)

Nowadays, biomarkers are recognized as valuable tools to complement chemical and ecological assessments in biomonitoring programs. They provide insights into the effects of contaminant exposures on individuals and establish connections between environmental pressure and biological response at higher levels. In the last decade, strong improvements in the design of experimental protocols and the result interpretation facilitated the use of biomarker across wide geographical areas, including aquatic continua. Notably, the statistical establishment of reference values and thresholds enabled the discrimination of contamination effects in environmental conditions, allowed interspecies comparisons, and eliminated the need of a reference site. The aim of this work was to study freshwater-estuarine-coastal water continua by applying biomarker measurements in multi-species caged organisms. During two campaigns, eight sentinel species, encompassing fish, mollusks, and crustaceans, were deployed to cover 25 sites from rivers to the sea. As much as possible, a common methodology was employed for biomarker measurements (DNA damage and phagocytosis efficiency) and data interpretation based on guidelines established using reference values and induction/inhibition thresholds (establishment of three effect levels). The methodology was successfully implemented and allowed us to assess the environmental quality. Employing multiple species per site enhances confidence in observed trends. The results highlight the feasibility of integrating biomarker-based environmental monitoring programs across a continuum scale. Biomarker results align with Water Framework Directive indicators in cases of poor site quality. Additionally, when discrepancies arise between chemical and ecological statuses, biomarker findings offer a comprehensive perspective to elucidate the disparities. Presented as a pilot project, this work contributes to gain insights into current biomonitoring needs, providing new questions and perspectives.

Influence of Storage Time on the DNA Integrity and Viability of Spermatozoa of the Spider Crab Maja brachydactyla

Natural populations of the spider crab Maja brachydactyla constitute a fishery resource of great economic importance in many countries. As in the rest of eubrachyurans, the females of this species have ventral-type seminal receptacles where they store sperm from copulations. Sperm can be stored in these structures for months and even years before egg fertilisation, with the consequent degradation of the sperm cells during the time. In this work, we analyse the viability and the possible genetic damage in sperm accumulated in the seminal receptacles of M. brachydactyla females as a function of the storage time (from 0 to 14 months) using the comet assay technique. On one hand, we developed an algorithm for comet image analysis that improves the comet segmentation compared with the free software Open comet v1.3.1 (97% vs. 76% of detection). In addition, our software allows the manual modification of the contours wrongly delimited via the automatic tool. On the other hand, our data show a sharp decline in sperm viability and DNA integrity in the first four months of storage, which could lead to a decrease in the fecundity rate and/or viability of the embryos or larvae from the second and third clutches of the annual cycle if the repair capacity in these gametic cells is low.

Comet assay in Aegla platensis (Decapoda: Anomura) using a non-lethal hemolymph field sampling for in situ monitoring of freshwater genotoxicity

This study aimed to apply the comet assay on Aegla platensis crabs as a suitable non-destructive approach for in situ monitoring of freshwater genotoxicity. Animals were captured during four sampling periods in a stream under minor anthropogenic impacts in Southern Brazil. Crabs were captured with a hand net, then the hemolymph samples were collected, and the animals were released into the stream after a 20-min recovery time. Hemolymph samples were transported to the laboratory and used to perform the alkaline comet assay. Results showed an intermediate level in the DNA damage index (range 107.3-165.0 arbitrary unit). No significant differences were observed among the different sampling periods. Hemolymph was successfully used as a non-lethal source of biological samples, and the comet assay using A. platensis proved to be a feasible approach for genotoxicity studies.

Application of the comet assay for the evaluation of DNA damage in mature sperm

DNA integrity is considered an important parameter of semen quality and is of significant value as a predictor of male fertility. Currently, there are several methods that can assess sperm DNA integrity. One such assay is the comet assay, or single-cell gel electrophoresis, which is a simple, sensitive, reliable, quick and low-cost technique that is used for measuring DNA strand breaks and repair at the level of individual cells. Although the comet assay is usually performed with somatic cells from different organs, the assay has the ability to detect genotoxicity in germ cells at different stages of spermatogenesis. Since the ability of sperm to remove DNA damage differs between the stages, interpretation of the results is dependent on the cells used. In this paper we give an overview on the use and applications of the comet assay on mature sperm and its ability to detect sperm DNA damage in both animals and humans. Overall, it can be concluded that the presence in sperm of significantly damaged DNA, assessed by the comet assay, is related to male infertility and seems to reduce live births. Although there is some evidence that sperm DNA damage also has a long-term impact on offspring's health, this aspect of DNA damage in sperm is understudied and deserves further attention. In summary, the comet assay can be applied as a useful tool to study effects of genotoxic exposures on sperm DNA integrity in animals and humans.

Developmental and reproductive effects in grass shrimp (Palaemon pugio) following acute larval exposure to a thin oil sheen and ultraviolet light

Many early stages of estuarine species congregate at the surface or in the upper mixing layer making them prone to UV light exposure and oil sheens. Laboratory testing was used to assess UV-oil sheen interactions with grass shrimp (Palaemon pugio). Newly hatched grass shrimp larvae were exposed to a 1-μm thick oil sheen for 24 h with or without an 8-h pulse of UV light. Grass shrimp were then transferred to clean seawater and non-UV conditions to measure development, growth, and reproductive fitness. Minimal toxicity was observed after the initial exposure but larval development was significantly delayed in shrimp exposed to the UV enhanced sheen. After reaching sexual maturity, shrimp were paired to evaluate effects on reproduction. Shrimp initially exposed to the UV enhanced sheen as larvae had a significant reduction in fecundity compared to controls. This demonstrates the importance of examining interactions between UV light and oil since negative effects to aquatic organisms may be underestimated if based on standard laboratory fluorescent lighting. Acute exposures of early life stages to thin oil sheens and UV light may lead to long-term impacts to individuals and ultimately to grass shrimp populations.

Coupling caging and proteomics on the European flounder (Platichthys flesus) to assess the estuarine water quality at micro scale

Estuaries are important areas highly vulnerable to anthropogenic pollutions. Therefore, the assessment of estuarine water quality is a major ecological issue. In this study, we sampled juveniles of the European flounder in the "pristine" Canche estuary, and caged them in Canche and in two polluted sites of the Seine estuary, Rouen and Fosse Nord. After one month, the metal and organic pollutants in these sites were assessed, and we evaluated several phenotypic indicators (condition index, RNA/DNA ratios and genotoxicity), and extracted the proteins in fish livers for analysis using a shotgun proteomics approach. The results showed strong modifications in the fish caged in both sites of the Seine estuary, as compared to those caged in Canche. In particular, many proteins involved in phase I and phase II detoxification reactions were accumulated in the liver of fish caged in the site showing the highest pollution, Rouen. In addition, we observed a general disruption of metabolism, in particular an increase in lipid synthesis and carbohydrate degradation in Rouen, and a decrease in the abundance of proteins associated to translational activity in Fosse Nord. At both sites, several stress proteins were decreased. The proteomic impact of the encagement by itself was also evaluated, by comparing the liver proteome of fish caged in Canche to that of fish stayed in natura during the same time. The results showed proteomic signatures of exposure to stressful conditions (particularly heat stress), most probably related to the micro-habitat in which the cages were placed. In conclusion, the caging technique is of great interest for ecotoxicological assessment of estuarine waters, but should consider that the results are representative of the micro-habitat around the cages, which does not necessarily represent the overall heterogeneity of the estuarine environment.

Association between semen quality among men with different occupational exposures and risk of recurrent spontaneous abortion in island residents

Objective: This study aimed to evaluate the semen quality of male adults whose spouses suffer from recurrent spontaneous abortion (RSA) in the island area, and to explore the association between RSA and occupational exposures.

Methods: A total of 131 male patients were recruited and divided into two groups: spouse with recurrent spontaneous abortion group (RSA group, [Formula: see text]) and the normal fertility group (control group, [Formula: see text]). Information such as height, weight and occupational exposure history of 131 men were obtained. Semen samples were collected and analyzed. Differences in semen parameters and DNA fragmentation index (DFI) between the two groups were compared. Odds ratios (ORs) and their corresponding 95% confidence intervals were calculated to evaluate the association between occupational exposures and RSA status.

Results: Overall, no significant difference was found in sperm concentration, progressive motility and normal morphology rate between RSA and control groups. Only DFI was observed to be significantly higher in the RSA group. Evaluation of the receiver operating characteristic (ROC) curve showed DFI (AUC: 0.623, [Formula: see text]) could discriminate between males from the couples with RSA and without RSA.

Conclusion: The analysis of conventional semen parameters could not directly reflect their influence on embryonic development, and test of integrity of the sperm DNA is of paramount importance to fully understand male fertility. It is crucial to conduct studies regarding occupational exposures and pregnancy loss and/or RSA risk, since it will provide population-level data to aid in the identification of important risk factors that warrant further mechanistic investigation, and eventually lead to effective prevention and treatment strategies.