Cellular Bioreactivity of Micro- and Nano-Plastic Particles in Oysters

The global usage of plastics has increased dramatically over the last several decades. Polystyrene (PS) is the fourth most common plastic material produced annually due to its many versatile applications. Consequently, there has been a coinciding increase in PS wastes, much of which makes its way into waterways and oceanic habitats. While plastic debris has been shown to adversely affect many marine species as a result of ingestion and entanglement, less is known about the cellular uptake of small-scale plastic particles (nano and micro) by marine invertebrates. In this study, we investigated the potential for uptake of PS nano and micron-sized beads (50 nm and 3 μm) by the Eastern Oyster, Crassostrea virginica. This research was focused on two key issues: (1) how particle size would affect uptake by hepatopancreas (HP) cells in vitro and (2) the difference in uptake of micron and nano particles in vivo between gill and HP tissues. This research confirmed that oysters can accumulate PS beads in their tissues, especially HP tissues. Furthermore, using fluorescent deconvolution microscopy, it was observed that plastic nanoparticles exhibited a much greater propensity for intracellular accumulation in HP cells, primarily into lysosomes via endosomal pathways, indicating the potential for significant bioreactivity and sublethal impacts. While exposures of whole oysters or isolated HP cells to bare PS beads did not cause any significant toxicity (acute or sublethal), nanoplastics are more likely to accumulate intracellularly and to deliver adsorbed toxins directly into cells

UNA MIRADA GLOBAL DEL ESTADO DE LAACUMULACIÓN POR METALES PESADOS POR HELMINTOS CON UNA NOTA EN EL USO DE CULTIVO IN VITRO DE ACANTOCÉFALOS ADULTOS PARA ESTUDIAR LOS MECANISMOS DE BIOACUMULACIÓN

Bioaccumulation of metals by helminths is a well acknowledged phenomenon that has triggered increasing research interest in the past two decades and found applications in environmental studies. The ecological literature is fairly abundant but still shows gaps with some taxa not having been studied. Variations in the ability of helminths to sequester various metals are recognized and a synthetic overview of the literature is provided herein. Adult acanthocephalans are known to be particularly efficient as bioaccumulators of heavy metals. We optimized an in vitro culture technique of the acanthocephalan Moniliformis moniliformis and initiated in vitro exposure to cadmium and lead. We propose to use this technique to study the mechanisms of uptake and sequestration of heavy metals, which are yet to be understood.La bioacumulación por metales por helmintos es un fenómeno bien reconocido que ha provocado un incremento de interés en investigación en las dos décadas pasadas y ha encontrado aplicaciones en estudios ambientales. La literatura ecológica es bastante abundante pero aun muestra lagunas con algunos taxas que no han sido estudiados. Variaciones en la habilidad de los helmintos para secuestrar varios metales son reconocidos y una sintética mirada global de la literatura es proporcionada aquí. Los acantocéfalos adultos son conocidos por ser particularmente eficientes como bioacumuladores de metales pesados. Optimizamos una técnica de cultivo in vitro del acantocéfalo Moniliformis moniliformise iniciamos una exposición in vitroa cadmio y plomo. Proponemos el uso de esta técnica para estudiar el mecanismo de captación y secuestro de metales, los cuales aun deben ser entendidos

Overviewof the status of heavy metal accumulation by helminths with a note on the use of in vitro culture of adult acanthocephalans to study the mechanisms of bioaccumulation

Bioaccumulation of metals by helminths is a well acknowledged phenomenon that has triggered increasing research interest in the past two decades and found applications in environmental studies. The ecological literature is fairly abundant but still shows gaps with some taxa not having been studied. Variations in the ability of helminths to sequester various metals are recognized and a synthetic overview of the literature is provided herein. Adult acanthocephalans are known to be particularly efficient as bioaccumulators of heavy metals. We optimized an in vitro culture technique of the acanthocephalan Moniliformis moniliformis and initiated in vitro exposure to cadmium and lead. We propose to use this technique to study the mechanisms of uptake and sequestration of heavy metals, which are yet to be understood.La bioacumulación por metales por helmintos es un fenómeno bien reconocido que ha provocado un incremento de interés en investigación en las dos décadas pasadas y ha encontrado aplicaciones en estudios ambientales. La literatura ecológica es bastante abundante pero aun muestra lagunas con algunos taxas que no han sido estudiados. Variaciones en la habilidad de los helmintos para secuestrar varios metales son reconocidos y una sintética mirada global de la literatura es proporcionada aquí. Los acantocéfalos adultos son conocidos por ser particularmente eficientes como bioacumuladores de metales pesados. Optimizamos una técnica de cultivo in vitro del acantocéfalo Moniliformis moniliformise iniciamos una exposición in vitroa cadmio y plomo. Proponemos el uso de esta técnica para estudiar el mecanismo de captación y secuestro de metales, los cuales aun deben ser entendidos

Dietary Uptake of Cu Sorbed to Hydrous Iron Oxide is Linked to Cellular Toxicity and Feeding Inhibition in a Benthic Grazer

Whereas feeding inhibition caused by exposure to contaminants has been extensively documented, the underlying mechanism(s) are less well understood. For this study, the behavior of several key feeding processes, including ingestion rate and assimilation efficiency, that affect the dietary uptake of Cu were evaluated in the benthic grazer <i>Lymnaea stagnalis</i> following 4–5 h exposures to Cu adsorbed to synthetic hydrous ferric oxide (Cu–HFO). The particles were mixed with a cultured alga to create algal mats with Cu exposures spanning nearly 3 orders of magnitude at variable or constant Fe concentrations, thereby allowing first order and interactive effects of Cu and Fe to be evaluated. Results showed that Cu influx rates and ingestion rates decreased as Cu exposures of the algal mat mixture exceeded 10⁴ nmol/g. Ingestion rate appeared to exert primary control on the Cu influx rate. Lysosomal destabilization rates increased directly with Cu influx rates. At the highest Cu exposure where the incidence of lysosomal membrane damage was greatest (51%), the ingestion rate was suppressed 80%. The findings suggested that feeding inhibition was a stress response emanating from excessive uptake of dietary Cu and cellular toxicity