Structure of nematocysts isolated from the fire corals Millepora alcicornis and Millepora complanata (Cnidaria: Hydrozoa)

García-Arredondo, Alejandro; Rojas, Antonio; Iglesias-Prieto, Roberto; Zepeda-Rodríguez, Armando; Palma-Tirado, Lourdes

doi:10.1590/s1678-91992012000100014

Cited by 12 publications

(8 citation statements)

References 19 publications

(18 reference statements)

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“…In the Mexican Caribbean, Millepora species are noted for their ability to induce burning pain and local reactions on human skin after contact. In fact, these species possess penetrating nematocysts [ 2 ]. In a previous study, we reported the concentration-dependent hemolytic activity of the aqueous extract of M. complanata on rat erythrocytes and found that this activity was heat-labile, which suggested that the hemolysins responsible for this activity were proteins [ 11 ].…”

Section: Discussionmentioning

confidence: 99%

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

García-Arredondo

Murillo-Esquivel

Rojas

et al. 2014

J Venom Anim Toxins incl Trop Dis

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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.

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Section: Discussionmentioning

confidence: 99%

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

García-Arredondo

Murillo-Esquivel

Rojas

et al. 2014

J Venom Anim Toxins incl Trop Dis

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“…Mexican marine biodiversity is extremely rich and the coral reefs of the Mexican Caribbean own a particularly high number of species; these include hydrozoans with calcareous exoskeleton of the genus Millepora (phylum Cnidaria; class Hydrozoa), which are the second-most abundant reef-forming organisms in coral reef ecosystems [ 1 ]. Like all cnidarians, Millepora species are armed with stinging cells, cnidocytes, that hold nematocysts, which consist of a capsule filled with venom that is injected through a tubule when a physical or chemical stimulus is detected [ 2 – 4 ].…”

Section: Introductionmentioning

confidence: 99%

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

Hernández-Matehuala¹,

Rojas‐Molina

Vuelvas-Solórzano

et al. 2015

J Venom Anim Toxins Incl Trop Dis

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BackgroundMillepora alcicornis is a branching hydrocoral common throughout the Caribbean Sea. Like other members of this genus, this species is capable of inducing skin eruptions and blisters with severe pain after contact. In the present study, we investigated the toxicity of the M. alcicornis aqueous extract on several animal models. Considering that some cnidarian hemolysins have been associated to local tissue damage, since they also induce lysis of other cell types, we also made a partial characterization of the hemolytic activity of M. alcicornis aqueous extract. This information is important for understanding the defense mechanisms of the “fire corals”.MethodsThe effects of pH, temperature, and some divalent cations on the hemolytic activity of the extract were assayed, followed by a zymogram analysis to detect the cytolysins and determine their approximate molecular weight. The toxicity of the aqueous extract was assayed in mice, by intravenous administration, and histopathological changes on several tissues were analyzed by light microscopy. The toxicity of the extract was also tested in Artemia salina nauplii, and the damages caused on the crustaceans were analyzed by transmission and scanning electron microscopy.ResultsThe hemolytic activity of the hydrocoral extract was enhanced in the presence of Ca2+ (≥2 mM), Mg2+ (≥6 mM), and Ba2+ (≥0.1 mM); however, it was reduced in the presence of Cu2+ (≥0.1 mM), Zn2+ (≥6 mM), and EDTA (≥0.34 mM). Differences in the pH did not affect the hemolytic activity, but it was temperature-sensitive, since preincubation at ≥ 50 °C sharply reduced hemolysis. The zymogram showed the presence of two types of hemolysins: ~ 28–30 kDa proteins with phospholipase A2 activity and ~ 200 kDa proteins that do not elicit enzymatic activity. The aqueous extract of this cnidarian was lethal to mice (LD50 = 17 μg protein/g), and induced kidney, liver, and lung damages. Under denaturing conditions, the aqueous extract completely lost its toxic and hemolytic activities.ConclusionsThe results showed that the M. alcicornis aqueous extract contains two types of thermolabile hemolysins: proteins of approximately 28–30 kDa with PLA2 activity, while the others are larger proteins of approximately 200 kDa, which do not possess PLA2 activity. Those thermolabile cytolysins, which are stable to pH changes and whose activity is calcium dependent, are capable of inducing damage in lung, kidney and liver tissues, resulting in a slow death of mice. M. alcicornis cytolysins also provoke tissue dissociation in Artemia salina nauplii that might be attributed to pore forming mechanisms.

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“…For example, most of the biological activities reported in this study for these corals are also induced by the aqueous extract of the hydrozoan fire coral M. complanata. Millepora species possess two types of nematocyst capable of penetrating human skin, macrobasic mastigophores and stenoteles [57]. In the current study we observed that these scleractinian corals possess mainly holotrich and p-rhabdoid nematocysts; however, a detailed study by electron microscopy is necessary for a proper identification.…”

Section: Discussionmentioning

confidence: 55%

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

García-Arredondo

Rojas‐Molina

Ibarra‐Alvarado

et al. 2016

J Venom Anim Toxins Incl Trop Dis

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BackgroundScleractinian corals (stony corals) are the most abundant reef-forming cnidarians found in coral reefs throughout the world. Despite their abundance and ecological importance, information about the diversity of their toxins and their biological activities is very scarce. In this study, the chemical composition and the biological activities of the aqueous extracts of Pseudodiploria strigosa, Porites astreoides and Siderastrea siderea, three scleractinian corals from the Mexican Caribbean, have been assessed for the first time.MethodsToxicity of the extracts was assessed in crickets; the presence of cytolysins was detected by the hemolysis assay; the vasoconstrictor activity was determined by the isolated rat aortic ring assay; the nociceptive activity was evaluated by the formalin test. The presence of phospholipases A2 (PLA2), serine proteases, and hyaluronidases was determined by enzymatic methods. Low-molecular-weight fractions were obtained by gel filtration chromatography and ultrafiltration.ResultsExtracts from the three species were toxic to crickets, induced hemolysis in human and rat erythrocytes, produced vasoconstriction on isolated rat aortic rings, and presented phospholipase A2 and serine-protease activity. Despite the fact that these corals are not considered to be harmless to humans, the extracts generated significant nociceptive responses. The matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry analysis of the low-molecular-weight fractions revealed the presence of peptides within a mass range of 3000 to 6000 Da. These fractions were toxic to crickets and two of them induced a transitory vasoconstrictor effect on isolated rat aortic rings.ConclusionThis study suggests that scleractinian corals produce low-molecular-weight peptides that are lethal to crickets and induce vasoconstriction.

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Structure of nematocysts isolated from the fire corals Millepora alcicornis and Millepora complanata (Cnidaria: Hydrozoa)

Cited by 12 publications

References 19 publications

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

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

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

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

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