Responsiveness of metallothionein and hemocyanin genes to cadmium and copper exposure in the garden snailCornu aspersum

Abstract

Terrestrial gastropods express metal‐selective metallothioneins (MTs) by which they handle metal ions such as Zn2+, Cd2+, and Cu+/Cu2+ through separate metabolic pathways. At the same time, they depend on the availability of sufficient amounts of Cu as an essential constituent of their respiratory protein, hemocyanin (Hc). It was, therefore, suggested that in snails Cu‐dependent MT and Hc pathways might be metabolically connected. In fact, the Cu‐specific snail MT (CuMT) is exclusively expressed in rhogocytes, a particular molluscan cell type present in the hemocoel and connective tissues. Snail rhogocytes are also the sites of Hc synthesis. In the present study, possible interactions between the metal‐regulatory and detoxifying activity of MTs and the Cu demand of Hc isoforms was explored in the edible snail Cornu aspersum, one of the most common European helicid land snails. This species possesses CdMT and CuMT isoforms involved in metal‐selective physiological tasks. In addition, C. aspersum expresses three different Hc isoforms (CaH ɑD, CaH ɑN, CaH β). We have examined the effect of Cd2+ and Cu2+ exposure on metal accumulation in the midgut gland and mantle of C. aspersum, testing the impact of these metals on transcriptional upregulation of CdMT, CuMT, and the three Hc genes in the two organs. We found that the CuMT and CaH ɑD genes exhibit an organ‐specific transcriptional upregulation in the midgut gland of Cu‐exposed snails. These results are discussed in view of possible interrelationships between the metal‐selective activity of snail MT isoforms and the synthesis and metabolism of Hc isoforms.

Oxidative response to accumulation of trace metals in tissue of two bivalves, the Asian green mussel Perna viridis and the blood cockle Tegillarca granosa, living in Pattani Bay, Thailand

“…Moreover, the separated metabolic and detoxification pathways for the two metals in different organisms were also indicated (Pedrini‐Martha et al. 2021; Figure 2).…”

Comparative transcriptome analysis of the gills and hepatopancreas from Macrobrachium rosenbergii exposed to the heavy metal Cadmium (Cd2+)

“…In contrast, hemocyanin-like protein, a crucial immune protein in arthropods 42 – 44 , had significantly increased expression after exposure to Cd 2+ . Heavy metals are handled through separate metabolic pathways dependent on hemocyanin 45 . In addition, the expression level of heat shock proteins (Hsps), common stress-inducible proteins, has been known to increase under various stressors, such as oxidative stress, heavy metals, and viral infections 46 – 48 .…”

Comparative transcriptome analysis of the gills and hepatopancreas from Macrobrachium rosenbergii exposed to the heavy metal Cadmium (Cd 2+ )

“…In contrast, hemocyanin-like protein, a crucial immune protein in arthropods [40][41][42] , was signi cantly increased expression after exposure to Cd 2+ . Heavy metals are handled through separate metabolic pathways dependent on hemocyanin 43 . In addition, the expression level of heat shock proteins (Hsps), common stress-inducible proteins, has been known to increase expression under various stressors, such as oxidative, and heavy metals, and viral infections [44][45][46] .…”