In vertebrates, hematopoiesis is regulated by inductive microenvironments (niches). Likewise, in the invertebrate model organism Drosophila melanogaster, inductive microenvironments known as larval Hematopoietic Pockets (HPs) have been identified as anatomical sites for the development and regulation of blood cells (hemocytes), in particular of the self-renewing macrophage lineage. HPs are segm...

We have studied the embryonic development of Drosophila hemocytes and their conversion into macrophages. Hemocytes derive exclusively from the mesoderm of the head and disperse along several invariant migratory paths throughout the embryo. The origin of hemocytes from the head mesoderm is further supported by the finding that in Bicaudal D, a mutation that lacks all head structures, and in twis...

The purpose of this study was to quantify the gene expression of lysozyme, an important antibacterial protein produced by shrimp hemocytes, within tissues of Litopenaeus vannamei Boone in response to a pathogen challenge. We quantified lysozyme transcripts with a real-time PCR method and used these data, along with total hemocyte counts, to infer patterns of hemocyte trafficking during the immu...

Hemocytes are the immune effectors in clams, directing cellular but also humoral defences. In the Manila clam (Ruditapes philippinarum) and the carpet shell clam (Ruditapes decussatus), two phenotypically similar venerid species, fishery and aquaculture importance motivated scientific studies to improve knowledge about the participation of hemocytes in immune response. Currently, gaps still per...

Bivalve hemocytes are involved in a variety of physiological and immunological functions. Circulating hemocytes in the hemolymph represent the main component of the internal self-defense system while hemocytes present in the extrapallial space (between the mantle and the shell) are actively involved in biomineralization and shell formation. This study focused on the characterization of hemocyte...

Lectins/carbohydrate binding can be involved in the Schistosoma mansoni recognition and activation of the Biomphalaria hemocytes. Therefore, expression of lectin ligands on Biomphalaria hemocytes would be associated with snail resistance against S. mansoni infection. To test this hypothesis, circulating hemocytes were isolated from B. glabrata BH (snail strain highy susceptible to S. mansoni), ...

A tetrazolium dye reduction assay was used to study factors governing the killing of bacteria by oyster hemocytes. In vitro tests were performed on bacterial strains by using hemocytes from oysters collected from the same location in winter and summer. Vibrio parahaemolyticus strains, altered in motility or colonial morphology (opaque and translucent), and Listeria monocytogenes mutants lacking...

Oysters were placed in an aquarium containing artificial seawater, and Cryptosporidium parvum oocysts were added. Oocysts were later found in the gill washings, hemocytes, and gut contents of the oysters. Hemocytes containing oocysts were intubated into four mice. C. parvum stages developed in the ileal epithelia of all of the mice, indicating that the oocysts in the hemocytes remained infective.

The disk abalone Haliotis discus discus and the spiny top shell Turbo cornutus are edible gastropod species of high economic value, mainly in Asia. Mortality outbreaks and variations in worldwide stock abundance have been reported and suggested to be associated, at least in part, with pathogenic infections. Ecology, biology and immunology of both species are currently not well documented. The c...

Hemocytes from two adult bivalves, Pecten maximus and Crassostrea gigas, were exposed to 12 different bacterial strains including 2 Alteromonas spp. (U1 and T413), 2 type strains of vibrios (V. anguillarum ATCC 19264 and V. alginolyticus ATCC 17749), 1 vibrio (S322) pathogenic to C. gigas larvae, 2 vibrios (V110 and V117) virulent to Ostrea edulis larvae, and 5 different strains of a same Vibri...