Emergence and Disappearance of an Immune Molecule, an Antimicrobial Lectin, in Basal Metazoa

Abstract

Sponges (phylum Porifera) represent the evolutionarily oldest metazoans that comprise already a complex immune system and are related to the crown taxa of the protostomians and the deuterostomians. Here, we demonstrate the existence of a tachylectin-related protein in the demosponge Suberites domuncula, termed Suberites lectin. The MAPK pathway was activated in response to lipopolysaccharide treatment of the three-dimensional cell aggregates, the primmorphs; this process was abolished by the monosaccharide D-GlcNAc. The cDNA encoding the S. domuncula lectin was identified and cloned; it comprises 238 amino acids (26 kDa) in the open reading frame. The deduced protein has one potential transmembrane region, three characteristic Cys residues, and six internal tandem repeats; it shares the highest sequence similarity with lectins from the horseshoe crab Tachypleus trunculus. The steady-state level of expression of the Suberites lectin rises in primmorphs in response to lipopolysaccharide, an effect that was prevented by co-incubation with D-GlcNAc. The natural sponge lectin was purified by affinity chromatography; it has a size of 27 kDa and displays antibacterial activity against the Gram-negative bacteria Escherichia coli and the Gram-positive bacteria Staphylococcus aureus. The putative protein, deduced from the cloned gene, is identical/similar to the purified natural protein, as demonstrated by immunological cross-reactivity with specific antibodies. We conclude that the S. domuncula lectin acts as an antibacterial molecule involved in immune defense against bacterial invaders.

The unique skeleton of siliceous sponges (Porifera; Hexactinellida and Demospongiae) that evolved first from the Urmetazoa during the Proterozoic: a review

“…This enzyme is able to depolymerize amorphous silica (Schröder et al, 2003a). The cDNA encoding the silicase has been identified in primmorphs from S. domuncula, applying the technique of differential display of transcripts.…”

Isolation and Characterization of Bioactive Protein from Green Algae Halimeda macrobola Acting as Antioxidant and Anticancer Agent

“…The isolation of bioactive proteins from green algae Halimeda macrobola used a procedure modified from previous methods [6,8] as follows: The selected algae were cut into small pieces and weighed as much as 500 g fresh weight, homogenized by using 500 mL buffer A solution in a waring blender, then filtered through a filter cloth. The filtrate was freeze-thawed 2-3 times and centrifuged at 6000 rpm, 4 ºC for 20 minutes.…”

Purification and Gene Cloning of a Novel Antibacterial Phospholipase A2 from the Sponge Agelas Clathroides In Kapoposang Island Indonesia Terrestrial

“…Extraction and isolation of sponge PLA2 protein were conducted using previous methods as follows [16,17], 500 g of fresh sample sponge Agelas clathroides, homogenized with waring blender in 500 mL of buffer A (Tris-HCl 0.1 M pH 8.3, NaCl 2 M, CaCl 2 0.01 M, β -mercaptoetanol 1 %, Triton X-100 0.5 %), filtered with buchner. The filtrate obtained was freezen and thawed between 2 or 3 times, and then centrifugized at 12,000 rpm and 4 o C for 30 minutes.…”

“…Antibacterial activity assays against E. coli, S. aureus, S. typhi, and V. cholerae was conducted using diffusion method [16,17] . All about 20 µL of samples (whole extract and protein fractions obtained at each purification step, approximately 4 µg), were applied on sterile paper disc (diameter 6 mm) and put on the agar surface of the bacterial test culture.…”