Identification of key genes and molecular pathways associated with claw regeneration in mud crab (Scylla paramamosain).

The mud crab (Scylla paramamosain) possesses extensive regenerative abilities, enabling it to replace missing body parts, including claws, legs, and even eyes. Studying the genetic and molecular mechanisms underlying regenerative ability in diverse animal phyla has the potential to provide new insights into regenerative medicine in humans. In the present study, we performed mRNA sequencing to reveal the genetic mechanisms underlying the claw regeneration in mud crab. Several differentially expressed genes (DEGs) were expressed in biological pathways associated with cuticle synthase, collagen synthase, tissue regeneration, blastema formation, wound healing, cell cycle, cell division, and cell migration. The top GO enrichment terms were microtubule-based process, collagen trimer, cell cycle process, and extracellular matrix structural constituent. The most enriched KEGG pathways were ECM-receptor interaction and focal adhesion. The genes encoding key functional proteins, such as collagen alpha, cuticle protein, early cuticle protein, arthrodial cuticle protein, dentin sialophosphoprotein (DSPP), epidermal growth factor receptor (EGFR), kinesin family member C1 (KIFC1), and DNA replication licensing factor mcm2-like (MCM2) were the most significant and important DEGs suspected to participate in claw regeneration. The findings of this research offer a comprehensive and insightful understanding of the genetic and molecular mechanisms underlying claw regeneration in S. paramamosain. By elucidating the specific genes and molecular pathways implicated in this process, our study contributes significantly to the broader field of regenerative biology and offers potential avenues for further exploration in crustacean limb regeneration.

Combined effects of polystyrene microplastics and copper on antioxidant capacity, immune response and intestinal microbiota of Nile tilapia (Oreochromis niloticus).

Microplastics (MPs) coexist with other pollutants (such as heavy metals) in water, adversely impacting aquatic organisms, which might cause unpredictable ecological risks. This study aims to evaluate the effect of copper (Cu2+) and polystyrene microplastics (PS-MPs) on antioxidant capacity, immune response and intestinal microbiota of Nile tilapia. Cu2+ and PS-MPs co-exposure enhanced Cu2+ bioaccumulation in the liver of fish compared with Cu2+-alone exposure. Fish exposed to PS-MPs and Cu2+ displayed histopathologic alterations in the liver, intestine and gill. Exposure at low concentrations of Cu2+ in the C0 and CP0 groups can improve antioxidant capacity and immune response, while oxidative damage and inflammation existed in the high concentration of Cu2+ groups. Intestinal microbiota results showed that the diversity and structure were changed by Cu2+ and PS-MPs exposure, and harmful bacterium even increased at high concentration of Cu2+ and PS-MPs exposure groups. All in all, PS-MPs aggravate the accumulation of Cu2+ and lead to perturbations in biological systems of Nile tilapia.