An unusual cuticular tumor-like growth on the abdomen of a lobster, Homarus americanus

Hemocytic sarcoma of the body wall in a California king crab Paralithodes californiensis

Neoplasia is rarely reported in decapod crustaceans, and sarcoma has not been previously reported in any crab species. A California king crab Paralithodes californiensis with a recent history of autotomy (4 legs lost) and anorexia was found dead. Grossly, the crab had a pigmented ulcer on the right cheliped merus. Necropsy tissue samples were placed in 10% neutral buffered formalin and processed routinely for histology. Both histochemical (i.e. Brown and Brenn Gram, Fite-Faraco acid fast, Fontana-Masson, Giemsa, hematoxylin and eosin, Masson's trichrome, periodic acid-Schiff [PAS], phosphotungstic acid-hematoxylin, and von Kossa) and immunohistochemical (i.e. cytokeratin, vimentin, and lysozyme) stains were performed. The body wall (presumably of the right cheliped merus) was ulcerated and subtended by a densely cellular, unencapsulated, invasive neoplasm composed of spindle cells arranged in intersecting streams and bundles embedded in a small to moderate amount of fibromatous stroma. Neoplastic cells were oval to elongate with fibrillar, pale eosinophilic cytoplasm that occasionally contained moderate numbers of small, spherical, brightly eosinophilic granules that were highlighted with PAS and Giemsa stains. Neoplastic cells had mild atypia and no evident mitoses. Immunohistochemical stains were noncontributory. This neoplasm is consistent with hemocytic sarcoma of semi-granulocytic origin. Decapod crustaceans have 3 types of hemocytes: hyalinocytes, granulocytes, and semi-granulocytes. Neoplastic cells had PAS- and Giemsa-positive granules, which are present in both semi-granulocytes and granulocytes. Semi-granulocytes can elongate and are associated with deposition of extracellular matrix during some immune responses. Neoplastic cells were elongate and associated with deposition of matrix. These findings suggest neoplastic cells were of semi-granulocytic origin.

Characterization and functional analysis of a novel gC1qR in the swimming crab Portunus trituberculatus

The receptor for the globular head of complement component C1q, gC1qR, is a multifunctional and multiligand binding protein with a crucial role in host defense. In the present study, a full-length cDNA sequence of a gC1qR homolog (PtgC1qR) in Portunus trituberculatus was identified. PtgC1qR was a 268-amino-acid polypeptide with a conserved MAM33 domain and a mitochondrial targeting sequence in the first 56 amino acids. The transcripts of PtgC1qR were detected in all examined tissues with the highest level detected in the hepatopancreas. Compared with other early embryonic stages, PtgC1qR was highly expressed in the fertilized eggs and embryos at the cleavage stage, which suggest PtgC1qR may be a maternal gene. The transcripts of PtgC1qR in hemocytes exhibited time-dependent response expression pattern after challenged with bacteria (Vibrio alginolyticus, Micrococcus luteus) and fungi (Pichia pastoris). Moreover, the recombinant PtgC1qR (rPtgC1qR) exhibited strong antibacterial activity and microbial-binding activity, suggesting its crucial role in immune defense and recognition. Further phenoloxidase (PO) assay showed that rPtgC1qR could suppress the crab PO activity in vitro in a dose-dependent manner, and it could result in nearly 100% inhibition of PO activity under the concentration of 11.65 μM. Knockdown of PtgC1qR could significantly enhance the expression of serine protease related genes (PtSP1-3 and PtSPH), proPO-associated genes (PtproPO and PtPPAF) and C3-like genes (Ptα2M1 and PtTEP). However, the phagocytosis related genes (PtMyosin, PtRab5 and PtArp) and Ptα2M2 were significantly down-regulated in the PtgC1qR silenced crabs. These findings together demonstrate that PtgC1qR might function in crab immune response via its antibacterial activity, immune recognition or regulating the proPO system, complement pathway and phagocytosis.

Invertebrate Oncology: Diseases, Diagnostics, and Treatment

Neoplasia is a documented occurrence across invertebrate taxa, but challenges remain with regard to tumor diagnosis and treatment. Literature reports of neoplasia are frequent in mollusks and insects, infrequent in Cnidaria and crustaceans, and are yet to be documented in Porifera and echinoderms. A significant contribution could be made by veterinary practitioners documenting and treating neoplasms in invertebrates. Traditional methods of veterinary diagnosis are encouraged, but the anatomy and tissue biology of each invertebrate species need to be considered. Most neoplasms described in the invertebrate literature have been considered benign, making external lesions potentially amenable to surgical resection.

Identification and function of a novel C1q domain-containing (C1qDC) protein in triangle-shell pearl mussel (Hyriopsis cumingii)

C1q is the target recognition sequence of the classical complement pathway and a major link that connects innate and acquired immunity. In this study, a C1qDC homolog, HcC1qDC5, from the triangle-shell pearl mussel (Hyriopsis cumingii) was identified. The complete nucleotide sequence of HcC1qDC5 cDNA consists of a 5'-untranslated terminal region (UTR) of 123 bp, a 3'-UTR of 105 bp with a poly(A) tail, and an open reading frame (ORF) of 1344 bp, which encodes a polypeptide of 447 amino acids. HcC1qDC5 contains a signal peptide and three typical C1q domains. The HcC1qDC5 gene was expressed in all tested tissues, with the highest expression in the mantle. Staphylococcus aureus or Vibrio parahaemolyticus infection increased the mRNA transcript levels of HcC1qDC5 in the hepatopancreas and mantle. The recombinant HcC1qDC5 protein could bind to Gram-negative and Gram-positive bacteria as well as to different PAMPs (LPS and PGN). RNAi results showed that HcC1qDC5 was involved in V. parahaemolyticus-induced HcTNF and HcWAP expression. The combined results demonstrated that HcC1qDC5 participates in the innate immunity of H. cumingii.

Cancer across the tree of life: cooperation and cheating in multicellularity

Multicellularity is characterized by cooperation among cells for the development, maintenance and reproduction of the multicellular organism. Cancer can be viewed as cheating within this cooperative multicellular system. Complex multicellularity, and the cooperation underlying it, has evolved independently multiple times. We review the existing literature on cancer and cancer-like phenomena across life, not only focusing on complex multicellularity but also reviewing cancer-like phenomena across the tree of life more broadly. We find that cancer is characterized by a breakdown of the central features of cooperation that characterize multicellularity, including cheating in proliferation inhibition, cell death, division of labour, resource allocation and extracellular environment maintenance (which we term the five foundations of multicellularity). Cheating on division of labour, exhibited by a lack of differentiation and disorganized cell masses, has been observed in all forms of multicellularity. This suggests that deregulation of differentiation is a fundamental and universal aspect of carcinogenesis that may be underappreciated in cancer biology. Understanding cancer as a breakdown of multicellular cooperation provides novel insights into cancer hallmarks and suggests a set of assays and biomarkers that can be applied across species and characterize the fundamental requirements for generating a cancer.

Characterization of a gC1qR from the giant freshwater prawn, Macrobrachium rosenbergii

gC1qR, as a multicompartmental and a multifunctional protein, plays an important role in innate immunity. In this study, a gC1qR homolog (MrgC1qR) in the giant freshwater prawn, Macrobrachium rosenbergii was identified. MrgC1qR, a 258-amino-acid polypeptide, shares high identities with gC1qR from other species. MrgC1qR gene was expressed in different tissues and was highest expressed in the hepatopancreas. In addition, the MrgC1qR transcript was significantly enhanced after 6 h of white spot syndrome virus (WSSV) infection or post 2 h, 24 h of Vibrio anguillarum challenge compared to appropriate controls. Moreover, recombinant MrgC1qR (rMrgC1qR) had bacterial binding activity, the result also revealed that rMrgC1qR could bind pathogen-associated molecular patterns (PAMPs) such as LPS or PGN, suggesting that MrgC1qRmight function as a pathogen-recognition receptor (PRR). Furthermore, glutathione S-transferase (GST) pull-down assays showed that rMrgC1qR with GST-tag could bind to rMrFicolin1 or rMrFicolin2 with His-tag. Altogether, these results may demonstrate a role for MrgC1qR in innate immunity in the giant freshwater prawns.