Characteristics of hemolytic activity induced by the aqueous extract of the Mexican fire coral Millepora complanata

Abstract

BackgroundMillepora complanata is a plate-like fire coral common throughout the Caribbean. Contact with this species usually provokes burning pain, erythema and urticariform lesions. Our previous study suggested that the aqueous extract of M. complanata contains non-protein hemolysins that are soluble in water and ethanol. In general, the local damage induced by cnidarian venoms has been associated with hemolysins. The characterization of the effects of these components is important for the understanding of the defense mechanisms of fire corals. In addition, this information could lead to better care for victims of envenomation accidents.MethodsAn ethanolic extract from the lyophilized aqueous extract was prepared and its hemolytic activity was compared with the hemolysis induced by the denatured aqueous extract. Based on the finding that ethanol failed to induce nematocyst discharge, ethanolic extracts were prepared from artificially bleached and normal M. complanata fragments and their hemolytic activity was tested in order to obtain information about the source of the heat-stable hemolysins.ResultsRodent erythrocytes were more susceptible to the aqueous extract than chicken and human erythrocytes. Hemolytic activity started at ten minutes of incubation and was relatively stable within the range of 28-50°C. When the aqueous extract was preincubated at temperatures over 60°C, hemolytic activity was significantly reduced. The denatured extract induced a slow hemolytic activity (HU50 = 1,050.00 ± 45.85 μg/mL), detectable four hours after incubation, which was similar to that induced by the ethanolic extract prepared from the aqueous extract (HU50 = 1,167.00 ± 54.95 μg/mL). No significant differences were observed between hemolysis induced by ethanolic extracts from bleached and normal fragments, although both activities were more potent than hemolysis induced by the denatured extract.ConclusionsThe results showed that the aqueous extract of M. complanata possesses one or more powerful heat-labile hemolytic proteins that are slightly more resistant to temperature than jellyfish venoms. This extract also contains slow thermostable hemolysins highly soluble in ethanol that are probably derived from the body tissues of the hydrozoan.

Composition and biological activities of the aqueous extracts of three scleractinian corals from the Mexican Caribbean: Pseudodiploria strigosa, Porites astreoides and Siderastrea siderea

“…The results obtained in this study showed that rat erythrocytes were more sensitive to P. strigosa and S. siderea extracts, while the P. astreoides extract was more potent in human erythrocytes. Upon comparison with our previous study on the hemolytic properties of M. complanata aqueous extract [6], we found that P. strigosa extract was significantly more potent than M. complanata in both types of erythrocytes. These results suggest important differences between the hemolytic mechanisms of these reef-forming cnidarians.…”

“…It is well-documented that the venomous content of nematocysts comprises mainly proteins and peptides such as enzymes, pore-forming components, and neurotoxins that specifically modulate several types of ion channels [3, 4]. Non-nematocystic toxins have also been found in cnidarian tissues [5, 6]; most of them are secondary metabolites that are usually released to their surroundings as antipredatory, antimicrobial, allelopathic, and antifouling agents [7]. …”

Cytolytic and systemic toxic effects induced by the aqueous extract of the fire coral Millepora alcicornis collected in the Mexican Caribbean and detection of two types of cytolisins

“…Concerning cytolysins with PLA 2 activity, kinetic studies have revealed that these enzymes can display different affinities for membranes depending on the phospholipid composition [ 26 ]. In a previous study, regarding characterization of the hemolytic activity of the aqueous extract of M. complanata collected in the Mexican Caribbean, we found a similar behavior on the erythrocytes susceptibility to lysis [ 27 ], which suggests that cytolysins produced by both Caribbean hydrocorals have a high similarity in the membrane-binding domains. These results are in contrast with those found by Shiomi et al [ 9 ], who tested the hemolytic activity of M. dichotoma and M. platyphylla venoms on cow, horse, sheep, rabbit, guinea pig, mouse, and chicken erythrocytes.…”

Heated Debates: Hot-Water Immersion or Ice Packs as First Aid for Cnidarian Envenomations?

“…There is abundant evidence from in vitro and in vivo studies which suggest that cndarian venoms from all classes in the phylum are heat labile (Table 4) [31,32,33,34,35,36,37,38,39,40,41,42,43,44,45]. Some have suggested that the mechanism by which heat provides pain relief is unrelated to inactivation of venom components.…”