Reproductive toxicity is an emerging topic in Ecotoxicology aimed to evaluate adverse impact of environmental stressors to reproductive systems and processes. Sexual reproduction is the complex process that marks the creation of a new individual of the same species and is underlined by gamete activation and interaction. Gamete quality is therefore a critical factor in reproductive success and is defined as the capacity of a gamete to fertilize and be fertilized.  In marine animals with external fertilization, gametes are released in the sea water and may be affected by a variety of stressors as xenobiotics, global warming and acidification. In order to monitor marine water health status, sperm toxicity tests appear to be of fundamental importance; in this line, several studies are addressed to evaluate physiological parameters of sperm quality as concentration, motility, morphology and viability.  In marine animals impairment of sperm viability due to contaminated waters may affect fertilization capability, transmit damages to the offspring with a possible repercussion on development, fitness and even species survival.

Fig. 1. In the left column the three marine invertebrates: the ascidian Ciona robusta (top); the sea urchin Paracentrotus lividus (middle); the mollusk Mytilus galloprovincialis (bottom).
In the middle column live spermatozoa of the three species stained with SYBR-14 emitting green fluorescence.
In the right column dead spermatozoa of the three species stained with propidium iodide emitting red fluorescence.

Invertebrates are key species in the marine ecosystem, among them three species as the ascidian Ciona robusta (aka Ciona intestinalis sp.A), the sea urchin Paracentrotus lividus and the mollusk Mytilus galloprovincialis play an ecological role and are used as model for biomonitoring marine pollution.

On these species, we have used a new approach for determining the viability of spermatozoa, based on a dual DNA fluorescent staining for living (SYBR-14) and degenerated (propidium iodide) cells (Fig. 1).

So far the DNA staining method was associated with fluorescence microscopy or flow cytometry, two time consuming and expensive techniques. On the contrary we used  spectrofluorimetric analysis and to our knowledge, no analyses were previously made  combining the dual staining and fluorimetry. This approach resulted to us highly sensitive, simple, rapid  and cost-effective providing an easy  discrimination between live and dead spermatozoa.

The utility of this new method fits with the increasing need to study the impact of environmental toxicity on reproductive mechanisms at either minimum cost and time  and maximum sensitivity. Assessment of sperm viability is a very promising tool by which marine pollutants may be screened for spermiotoxicity in ecotoxicological studies.

Alessandra Gallo¹, Raffaele Boni², Elisabetta Tosti^1
1Stazione Zoologica Anton Dohrn, Napoli, Italy
²University of Basilicata, Potenza, Italy

Publication

Sperm viability assessment in marine invertebrates by fluorescent staining and spectrofluorimetry: A promising tool for assessing marine pollution impact.
Gallo A, Boni R, Tosti E
Ecotoxicol Environ Saf. 2018 Jan

Read offline:     

Related Articles:

	WRGSD: improving reliability and efficiency for coastal… Water-quality response grid-based sampling design (WRGSD) using optimization and multi-factors assessment can reliably detect a variety of the impact of human activities. The sampling design are optimized by clustering and…
	Ecotoxicology at the era of biocontrol expansion The French network ECOTOX questioned recently the implementation of ecotoxicology tools and concepts within the elaboration of biocontrol strategies. Ecotoxicology is defined as the science which studies the impacts of…
	Epigenetic phenotype diversification helps animals to adapt… There is increasing evidence that epigenetic phenotype variation can contribute to environmental adaptation, speciation and evolution. Epigenetic changes of the phenotype are caused by differences in gene expression rather than…
	Excess nutrients cause environmental deterioration in the… The introduction of excess nutrients (i.e., nitrogen and phosphorus) to coastal areas can have a series of impacts. One of the most common is eutrophication—the enrichment of water with surplus…
	Reproductive differences between cultured and wild corals Taiwan’s National Museum of Marine Biology & Aquarium (NMMBA) has focused on the artificial propagation of corals for years. In 2014, natural spawning of gametes of various cultured corals was…
	The noxious effects of benthic diatoms on marine… Diatoms dominate various marine and freshwater environments, at any latitude, and are responsible for up to 25% of primary production. They may be either free-living in the water column or…