A Comparative Analysis of Mucus Immunomodulatory Properties from Seven Marine Gastropods from the Mediterranean Sea.

The treatment of inflammatory and immune-related diseases due to dysfunctioning of the immune system necessitates modulation of the immune response through immunomodulatory compounds. Marine environments are considered as a new frontier for health benefit product implementations. Marine biodiversity is still a low explored resource, despite it is expected to represent an important platform for chemical bioactive compounds. Within the phylum Mollusca, gastropods are known to synthetize mucus, the latter presenting relevant bioactive properties, e.g., related to immunomodulant molecules able to activate the innate and acquired immune system. This study proposes a bioprospecting of the immunomodulant activity of mucus isolated from seven common gastropod species from the Gulf of Naples (Mediterranean Sea). Results showed that not all mucus displayed a significant cytotoxic activity on the two human cancer cell lines A549 and A2058. On the other hand, the mucus from Bolinus brandaris was strongly bioactive and was therefore thoroughly investigated at cellular, molecular, and protein levels on the human monocytes U937 line. It can conclusively induce monocyte differentiation in vitro and significantly stimulate natural immunity response.

Caenogastropod mitogenomics.

In order to further resolve the phylogenetic relationships within Caenogastropoda, the complete mitochondrial (mt) genomes of Cochlostoma hidalgoi (Cyclophoroidea), Naticarius hebraeus (Naticoidea), Galeodea echinophora (Tonnoidea), and Columbella adansoni (Buccinoidea), and the partial mt genome of Erosaria spurca (Cypraeoidea) were sequenced. All newly determined mt genomes conformed to the consensus gene order of caenogastropods, except that of C. hidalgoi, which differed in the relative positions of the trnD, trnQ, trnG, trnY, and trnT genes. Phylogenetic reconstruction of the caenogastropod tree was performed using probabilistic methods and based on the deduced amino acid sequences of concatenated mt protein coding genes. The reconstructed phylogeny recovered Architaenioglossa (superfamilies Cyclophoroidea, Ampullarioidea, and Viviparoidea) as a grade. The monophyly of Sorbeoconcha (all caenogastropods but Architaenioglossa) was supported by most but not all phylogenetic analyses (excluding Vermetoidea, which has a long branch). The relative phylogenetic position of Cerithioidea with respect to Hypsogastropoda remains unresolved. The monophyly of Hypsogastropoda (without Vermetoidea) is strongly supported. Within this clade, Littorinimorpha should be considered a grade. Several superfamilies (Abyssochrysoidea, Rissooidea, Truncatelloidea, and Naticoidea) branched off successively before a siphonate clade (Stromboidea, Cypraeoidea, Tonnoidea, Neogastropoda), which is strongly supported. The relative phylogenetic position of Vermetoidea could not be determined due to long-branch attraction artifacts. The superfamily Tonnoidea was recovered within Neogastropoda, which questions the monophyly of the latter as traditionally defined. The polyphyly of Muricoidea could be tentatively resolved excluding the families Volutidae and Babyloniidae, which would imply raising them to the rank of superfamilies.

The complete mitochondrial genome of Scutopus ventrolineatus (Mollusca: Chaetodermomorpha) supports the Aculifera hypothesis.

BACKGROUND: With more than 100000 living species, mollusks are the second most diverse metazoan phylum. The current taxonomic classification of mollusks recognizes eight classes (Neomeniomorpha, Chaetodermomorpha, Polyplacophora, Monoplacophora, Cephalopoda, Gastropoda, Bivalvia, and Scaphopoda) that exhibit very distinct body plans. In the past, phylogenetic relationships among mollusk classes have been contentious due to the lack of indisputable morphological synapomorphies. Fortunately, recent phylogenetic analyses based on multi-gene data sets are rendering promising results. In this regard, mitochondrial genomes have been widely used to reconstruct deep phylogenies. For mollusks, complete mitochondrial genomes are mostly available for gastropods, bivalves, and cephalopods, whereas other less-diverse lineages have few or none reported. RESULTS: The complete DNA sequence (14662 bp) of the mitochondrial genome of the chaetodermomorph Scutopus ventrolineatus Salvini-Plawen, 1968 was determined. Compared with other mollusks, the relative position of protein-coding genes in the mitochondrial genome of S. ventrolineatus is very similar to those reported for Polyplacophora, Cephalopoda and early-diverging lineages of Bivalvia and Gastropoda (Vetigastropoda and Neritimorpha; but not Patellogastropoda). The reconstructed phylogenetic tree based on combined mitochondrial and nuclear sequence data recovered monophyletic Aplacophora, Aculifera, and Conchifera. Within the latter, Cephalopoda was the sister group of Gastropoda and Bivalvia + Scaphopoda. CONCLUSIONS: Phylogenetic analyses of mitochondrial sequences showed strong among-lineage rate heterogeneity that produced long-branch attraction biases. Removal of long branches (namely those of bivalves and patellogastropods) ameliorated but not fully resolved the problem. Best results in terms of statistical support were achieved when mitochondrial and nuclear sequence data were concatenated.