Bursatella leachii purple ink secretion extract exerts cytotoxic properties against human hepatocarcinoma cell line (HepG2): In vitro and in silico studies

Liver cancer is the third leading cause of cancer death worldwide. Marine mollusc-derived extracts have gained attention as new potential natural-based anticancer agents to overcome the side effects caused by conventional chemotherapeutic drugs during cancer therapy. We evaluated the cytotoxic effects of a crude extract from the purple-ink released by the sea hare named Bursatella leachii (B. leachii) against human hepatocarcinoma cell line (HepG2) and explored the underlying mechanisms causing the programmed cell death (i.e., apoptosis). Expression of cleaved-caspase-8 and cleaved-caspase-3, key cysteine-aspartic proteases involved in the initiation and completion of the apoptosis process, appeared after HepG2 cell exposure to B. leachii extract. Gene expression levels of pro-apoptotic BAX, tumour suppressor TP53 and Cyclin D1 were increased after treatment with B. leachii. Using liquid chromatography-mass spectrometry, the main biomolecules in the B. leachii extract were identified as hectochlorin, malyngamide X, malyngamide S, bursatellin, and lyngbyatoxin A. Applying in silico approaches, the high scores predicted bioactivities for the five compounds were protease and kinase inhibitors. The ADME and cytochrome profiles for the compounds were also predicted. Altogether, the cytotoxic B. leachii extract presents high pro-apoptotic potentials, suggesting it as a promising safe natural product-based drug for the treatment of liver cancer.

Molecular and morphological systematics of Bursatella leachii de Blainville, 1817 and Stylocheilus striatus Quoy & Gaimard, 1832 reveal cryptic diversity in pantropically distributed taxa (Mollusca : Gastropoda : Heterobranchia)

The ragged sea hare (Bursatella leachii) and the long-tailed sea hare (Stylocheilus striatus) are two widely distributed species of benthic heterobranch sea slugs. In this paper, integrative taxonomic analyses have been conducted to detect possible cryptic diversity. Our results revealed that both nominal species are actually species complexes, consisting of five genetically distinct taxa. Two of them belong to the genus Bursatella and three to the genus Stylocheilus. The name B. leachii is retained for a widely distributed species, present in the Atlantic, the Mediterranean, and parts of the Indo-Pacific region. The name B. ocelligera is resurrected for the other species, restricted to the Indo-Pacific and co-occurring with B. leachii in that area. With the present data, it is not possible to test whether B. leachii and B. ocelligera have evolved allopatrically in the Atlantic and Indo-Pacific or sympatrically in the latter. Bursatella leachii has been able to maintain gene flow between the Atlantic and the Indo-Pacific Oceans, possibly because of a combined effect of the Agulhas Leakage process and the ability to survive the colder waters of South Africa. On the contrary, the three species of Stylocheilus are allopatric; the name S. striatus is retained for an Indo-Pacific species, while the names S. polyomma and S. rickettsi are resurrected for species inhabiting the Western Atlantic and the Eastern Pacific respectively. Finally, the discovery of a museum specimen mistakenly identified as B. leachii, but bearing a shell in its adult form, led to the resurrection of the genus Phycophila, previously synonymised with Aplysia. Phycophila euchlora, the only species described to date, is distributed in the Central and Western Pacific Ocean.

“New Mediterranean Biodiversity Records” (March 2017)

This Collective Article presents information on 22 species belonging to 5 Phyla, arranged geographically from from west to east. The new records were found in 8 countries as follows: Spain: first record of the two scarcely known nemerteans Baseodiscus delineatus and Notospermus geniculatus in Formentera; Malta: second record of the alien fish Lagocephalus sceleratus; Italy: the alien polychaete Syllis pectinans and the isopod Paranthura japonica, as well as the cryptogenic opisthobranch Anteaeolidiella lurana, were found in the fouling assemblages along the docks of the port of Livorno. New decapod records are reported from Sicily (the alien Callinectes sapidus and the native Pachygrapsus maurus) and Apulia (Percnon gibbosus and Procambarus clarkii); the lesser amberjack Seriola fasciata extended its geographical range to the Egadi Isands and Siganus luridus was documented for the first time along the Ionian coasts of Apulia and Calabria. Slovenia: the first record of the alien bivalve Brachidontes pharaonis is reported, together with a survey of up to date Adriatic records. Greece: the first record of the gastropod Rhinoclavis kochi is reported from Gavdos island. In addition, two records of endangered and rare cartilaginous fish were reported, namely, the shark Hexanchus griseus and the ray Leucoraja fullonica, as well as additional records of Siganus luridus for Lesvos and Malleus regula and Fulvia fragilis from Astypalaia. Turkey: the black wing flyingfish Hirundichthys rondeletii is reported for the very first time from the Black Sea. Egypt: the Indo-Pacific crab Halimede ochtodes is reported as established in Port Said. In addition, biometric parameters and meristic counts are reported for Anthias anthias in Damietta. Cyprus: the alien opisthobranch gastropod Bursatella leachii is reported for first time.