Opsonic function of sialic acid specific lectin in freshwater crab Paratelphusa jacquemontii

Reconstruction of Eriocheir sinensis Y-organ Genome-Scale Metabolic Network and Differential Analysis After Eyestalk Ablation

Genome-scale metabolic network (GSMN) has been proven to be a useful tool for the system analysis of organism metabolism and applied to deeply explore the metabolic functions or mechanisms in many organisms, including model or non-model organisms. However, the systematic studies on the metabolisms of aquatic animals are seldom reported, especially the aquatic crustaceans. In this work, we reconstructed an Eriocheir sinensis Y-organ GSMN based on the transcriptome sequencing of Y-organ, which includes 1,645 reactions, 1,885 unigenes, and 1,524 metabolites distributed in 100 pathways and 11 subsystems. Functional module and centrality analysis of the GSMN show the main metabolic functions of Y-organ. Further analysis of the differentially expressed unigenes in Y-organ after eyestalk ablation reveals that 191 genes in the network were up-regulated and 283 were down-regulated. The unigenes associated with the ecdysone synthetic pathway were all up-regulated, which is consistent with the report on the increasing secretion of ecdysone after eyestalk ablation. Besides, we compared the Y-organ GSMN with that of E. sinensis eyestalk and hepatopancreas, and we analyzed the specific metabolisms in each organ. The specific metabolisms and pathways of these three networks are closely related to their corresponding metabolic functions. The GSMN reconstructed in this work provides a new method and many novel clues for further understanding the physiological function of Y-organ. It also supplies a new platform for the investigation of the interactions among different organs in the growth process of E. sinensis.

Roles and Biomedical Applications of Haemolymph Lectin

BACKGROUND

Lectins are class of proteins characterized by their ability to selectively bind carbohydrate moieties of glycoproteins. Many invertebrate lectins, especially derived from hemolymph, are being purified, and yet their functions and medical applications are subjects of major interest.

METHODS

Hemolymph lectins in invertebrates play a major role in protecting against many pathogens and microbes. Further, many hemolymph lectins show anticancer properties towards various cancer cell lines, which expresses globotriaosyl ceramides on their cell surface.

RESULTS

These vast repertoires of hemolymph lectins in recognizing and inhibiting the growth of various harmful microbes and cancerous cells have spurred the biochemist to use them in histochemical and cytochemical studies.

CONCLUSION

The present review will address the biological roles and biomedical applications of hemolymph lectin.

Hemocytes and hemocytic responses in the mole crab Emerita emeritus (Linnaeus 1767)

The mole crab, Emerita emeritus, collected from the sandy shores of a Chennai beach, was investigated for cellular immune responses based on the morphology and defensive reactions of the circulating haemocytes. Three haemocyte morphotypes were identified using light and electron microscopy, and separated in a discontinuous percoll gradient. A phagocytosis study using human B erythrocyte as a target cell under phase-contrast optics showed that granular and semi-granular haemocytes were phagocytic, and this response was enhanced by using serum (opsonin)-coated human B erythrocyte in unfractionated and fractionated haemocytes. Observation of TEM image of phagocytosis revealed that the initial recognition and binding of the target cell was restricted to granular and semigranular haemocytes, which were lacking with hyaline cells. However, the encapsulation of DEAE Sepharose CL 6B beads, either untreated or coated with serum (opsonin), was restricted to hyaline cells. This suggests the occurrence of two cell lines in haemocytes, based on the differences observed in the response of haemocytes to bind target cells for phagocytosis or encapsulation. The present study also differentiated the activation of PO in the plasma, serum, and haemocyte lysate supernatant (HLS).