Glutathionyl-biliverdin IXα, a new heme catabolite in a marine annelid: Sex and cell specific accumulation.
Abstract We have isolated and characterized the green pigment accumulating in coelomic cells (eleocytes) of the common clam worm Nereis virens by means of RP-HPLC and ESI-tandem mass spectrometry. This pigment is a novel biliverdin-glutathione conjugate in which the glutathione is linked to the biliverdin-backbone via a thioether bond. The yolk precursor vitellogenin, a female-specific high-density lipoprotein ( ρ = 1179 kg/m 3 ) with a native molecular mass of ∼500 kDa and a subunit mass of ∼150 kDa, is capable of transporting this pigment as well as heme. The sex-independent large discoidal lipoprotein present in the coelomic fluid, which is sequestered by the eleocytes, could also be sh…
One precursor, three apolipoproteins: The relationship between two crustacean lipoproteins, the large discoidal lipoprotein and the high density lipoprotein/β-glucan binding protein
The novel discoidal lipoprotein (dLp) recently detected in the crayfish, differs from other crustacean lipoproteins in its large size, apoprotein composition and high lipid binding capacity, We identified the dLp sequence by transcriptome analyses of the hepatopancreas and mass spectrometry. Further de novo assembly of the NGS data followed by BLAST searches using the sequence of the high density lipoprotein/1-glucan binding protein (HDL-BGBP) of Astacus leptodactylus as query revealed a putative precursor molecule with an open reading frame of 14.7 kb and a deduced primary structure of 4889 amino acids. The presence of an N-terminal lipid bind- ing domain and a DUF 1943 domain suggests the…
Annelid Coelomic Fluid Proteins
The coelomic cavity is part of the main body plan of annelids. This fluid filled space takes up a considerable volume of the body and serves as an important site of exchange of both metabolites and proteins. In addition to low molecular substances such as amino acids and glucose and lactate, the coelomic fluid contains different proteins that can arise through release from adjacent tissues (intestine) or from secretion by coelomic cells. In this chapter, we will review the current knowledge about the proteins in the annelid coelomic fluid. Given the number of more than 20,000 extant annelid species, existing studies are confined to a relatively few species. Most studies on the oligochaetes …
Lipid accumulation and metabolism in polychaete spermatogenesis: Role of the large discoidal lipoprotein
In most oviparous animals, lipoprotein-mediated lipid transport plays an important role in the nutrient supply for the oocyte. In male gametes, lipids are used as energy substrates in spermatozoa but nothing is yet known about their origin and metabolism throughout spermatogenesis. The lipid profiles analyzed from different stages of male germ cell development in the marine annelid Nereis virens were found to undergo a dramatic change from primary triacylglycerides at the beginning of germ cell development to cholesterol and phospholipids at the end of development as demonstrated by HPLC with evaporative light scattering detection and mass spectrometry. The uptake of a large discoidal lipop…
Crustacean Hemolymph Lipoproteins
Lipoproteins mediate the transport of apolar lipids in the hydrophilic environment of physiological fluids such as the vertebrate blood and the arthropod hemolymph. In this overview, we will focus on the hemolymph lipoproteins in Crustacea that have received most attention during the last years: the high density lipoprotein/β-glucan binding proteins (HDL-BGBPs), the vitellogenins (VGs), the clotting proteins (CPs) and the more recently discovered large discoidal lipoproteins (dLPs). VGs are female specific lipoproteins which supply both proteins and lipids as storage material for the oocyte for later use by the developing embryo. Unusual within the invertebrates, the crustacean yolk protein…
Lipoprotein-induced phenoloxidase-activity in tarantula hemocyanin.
Phenoloxidases play vital roles in invertebrate innate immune reactions, wound closure and sclerotization processes in arthropods. In chelicerates, where phenoloxidases are lacking, phenoloxidase-activity can be induced in the oxygen carrier hemocyanin in vitro by proteolytic cleavage, incubation with the artificial inducer SDS, or lipids. The role of protein-protein interaction has up to now received little attention. This is remarkable, as lipoproteins - complexes of proteins and lipids - are present at high concentrations in arthropod hemolymph. We characterized the three lipoproteins present in tarantula hemolymph, two high-density lipoproteins and one very high-density lipoprotein, and…
The Pandinus imperator haemolymph lipoprotein, an unusual phosphatidylserine carrying lipoprotein.
The haemolymph lipoprotein of the scorpion, Pandinus imperator was isolated and characterised. Contrary to the lipoproteins of insects and the discoidal HDL-lipoproteins of a crayfish and polychaete, the Pandinus lipoprotein consists of three instead of two apoproteins (apoPiLp I = 230 kDa, apoPiLp II = 130 kDa and apoPiLp III = 120 kDa). The apolipoproteins are arranged in varying stoichiometries as judged by cross-linking experiments. In lipoprotein samples from individual animals, the two smaller subunits occurred in a 1:1 stoichiometry, while the relative amount of the 230 kDa peptide varied. The lipoprotein is a slightly heart-shaped HDL with a diameter of approximately 15 nm. It is pr…
A discoidal lipoprotein from the coelomic fluid of the polychaete Nereis virens.
A discoidal lipoprotein was isolated from the coelomic fluid of the polychaete, Nereis virens, by density gradient centrifugation. The lipoprotein was present in both sexes and moved as a uniform band in an agarose gel. The average diameter of the lipoprotein particles determined by electron microscopy was 42 nm with a thickness of 10 nm. SDS electrophoresis showed two apoprotein subunits with molecular masses of 247 and 85 kDa, respectively. In lectin blots, both apoproteins were reactive with Concanavalin A indicating the presence of N-glycans. The small subunit was also reactive with peanut lectin, indicating additional O-glycosylation. The total lipid content was 48% and consisted mainl…