Proteomics of the haemolymph of the terrestrial crustacean Porcellio scaber reveals components of its innate immunity under baseline conditions.

The terrestrial crustacean Porcellio scaber is an established test organism in environmental research. We analysed the haemolymph proteome of P. scaber using a classical proteomic approach based on one-dimensional gel electrophoresis and tandem mass spectrometry. Using a publicly available protein database and our P. scaber transcriptome data, we have identified 76 proteins involved in cytoskeleton formation, protein degradation, vesicular transport, genetic information processing, detoxification, carbohydrate and lipid metabolism reflecting haemocyte metabolic activity, active intracellular transport, and intercellular communication. Compared with the data reported for other crustaceans, 28 of these P. scaber proteins have been linked to its immunity, among them hemocyanin, α-2-macroglobulin, phenoloxidase 3, superoxide dismutase, glutathione S-transferase, haemolymph clottable protein, and histones H4 and H2B. Our results thus provide a firm base for studying the innate immune response of P. scaber at the level of the haemolymph proteome. This knowledge is of particular importance in ecotoxicity studies with various environmental stressors where understanding physiological changes is important to reveal possible modes of action.

Microplastics, chlorpyrifos and their mixtures modulate immune processes in the terrestrial crustacean Porcellio scaber.

Microplastics and agrochemicals are common pollutants in terrestrial ecosystems. Their interaction during coexistence in soils may influence their fate and adverse effects on terrestrial organisms. The aim of this study was to investigate how the exposure to two types of microplastics; polyester fibres, and crumb rubber; induce changes in immune parameters of Porcellio scaber and if the co-exposure of microplastics affects the response induced by the organophosphate pesticide chlorpyrifos. A number of immune parameters, such as total haemocyte count, differential haemocyte count, and phenoloxidase-like activity were assessed. In addition, the acetylcholinesterase (AChE) activity in the haemolymph was evaluated as a measure of the bioavailability of chlorpyrifos. After three weeks of exposure, the most noticeable changes in the measured immune parameters and also a significantly reduced AChE activity were seen in chlorpyrifos-exposed animals. Both types of microplastic at environmentally relevant concentrations caused only slight changes in immune parameters which were not dependent on the type of microplastic, although the two types differed significantly in terms of the chemical complexity of the additives. Mixtures of chlorpyrifos and microplastics induced changes that differed from individual exposures. For example, alterations in some measured parameters suggested a reduced bioavailability of chlorpyrifos (AChE activity, haemocyte viability) caused by both types of microplastics exposure, but the increase of haemocyte count was promoted by the presence of fibres implying their joint action. In conclusion, this study suggests that immune processes in P. scaber are slightly changed upon exposure to both types of microplastics and microplastics can significantly modulate the effects of other co-exposed chemicals. Further research is needed on the short-term and long-term joint effects of microplastics and agrochemicals on the immunity of soil invertebrates.