Judith Sánchez-Rodríguez

A venom extract from the sea anemone Bartholomea annulata produces haemolysis and lipid peroxidation in mouse erythrocytes

The haemolytic and peroxidative effects of crude extracts from Bartholomea annulata, a common Caribbean sea anemone, were investigated in erythrocytes isolated from NIH male albino mice. Significant concentration-dependent effects were found on both haemolysis (evaluated as release of haemoglobin) and lipid peroxidation (as a common index of oxidative damage to membrane lipids) in red blood cells. Moreover, the incubation of erythrocytes in the presence of either a general antioxidant, reduced glutathione (GSH, 50 microM), or an iron chelator, desferrioxamine (DFA, 10 microM), resulted in a significant attenuation of haemolysis in both cases. In light of these findings, the in vitro toxicological characterization of the venom, as well as the involvement of oxygen radical-mediated membrane damage as a potential mechanism of toxicity associated with haemolysis are discussed.

Antimicrobial, Antiprotozoal, and Toxic Activities of Cnidarian Extracts from the Mexican Caribbean Sea

Abstract Antimicrobial, antiprotozoal, and toxic activities of crude extracts obtained from six cnidarian species [Cassiopea xamachana. (R.R. Bigelow, 1892), Carybdea marsupialis. (Linné, 1758), Linuche unguiculata. (Swartz, 1788), Bartholomea annulata. (Leseur, 1817), Lebrunia danae. (Duchassaing and Michelotti, 1860), and Stichodactyla helianthus. (Ellis, 1768)] from the Mexican Caribbean Sea were studied. The extract obtained from Linuche unguiculata. was found to be the most active against the yeast Candida albicans. and the protozoan Giardia lamblia. with 24 mm of inhibition zone diameter and an IC50 of 63.2 µg mL−1, respectively. Additionally, in an effort to assess the effects caused by the treatment of cnidarians toxins in vertebrates, we used tilapias (Oreochromis niloticus.) as a laboratory model. The results showed that only 44 mg kg−1 of jellyfish (Carybdea marsupialis.) toxin were necessary to cause significant mortality in fish. Tilapias treated with the Stichodactyla. toxin demonstrated hemolytic damage and cellular abnormalities.

Preliminary Results of the in Vivo and in Vitro Characterization of a Tentacle Venom Fraction from the Jellyfish Aurelia aurita

The neurotoxic effects produced by a tentacle venom extract and a fraction were analyzed and correlated by in vivo and in vitro approaches. The tentacle venom extract exhibited a wide range of protein components (from 24 to >225 kDa) and produced tetanic reactions, flaccid paralysis, and death when injected into crabs. Two chromatography fractions also produced uncontrolled appendix movements and leg stretching. Further electrophysiological characterization demonstrated that one of these fractions potently inhibited ACh-elicited currents mediated by both vertebrate fetal and adult muscle nicotinic acetylcholine receptors (nAChR) subtypes. Receptor inhibition was concentration-dependent and completely reversible. The calculated IC50 values were 1.77 μg/μL for fetal and 2.28 μg/μL for adult muscle nAChRs. The bioactive fraction was composed of a major protein component at ~90 kDa and lacked phospholipase A activity. This work represents the first insight into the interaction of jellyfish venom components and muscle nicotinic receptors.

Cnidarian Neurotoxic Peptides Affecting Central Nervous System Targets

Natural products from animal venoms have been used widely in the discovery of novel molecules with particular biological activities that enable their use as potential drug candidates. The phylum Cnidaria (jellyfish, sea anemones, corals zoanthids, hydrozoans, etc.) is the most ancient venomous phylum on earth. Its venoms are composed of a complex mixture of peptidic compounds with neurotoxic and cytolitic properties that have shown activity on mammalian systems despite the fact that they are naturally targeted against fish and invertebrate preys, mainly crustaceans. For this reason, cnidarian venoms are an interesting and vast source of molecules with a remarkable activity on central nervous system, targeting mainly voltage-gated ion channels, ASIC channels, and TRPV1 receptors. In this brief review, we list the amino acid sequences of most cnidarian neurotoxic peptides reported to date. Additionally, we propose the inclusion of a new type of voltage-gated sea anemone sodium channel toxins based on the most recent reports.

Electrophysiological activity of a neurotoxic fraction from the venom of box jellyfish Carybdea marsupialis.

Carybdea marsupialis is a widely distributed box jellyfish found in the Mediterranean and in the tropical waters of the Caribbean Sea. Its venom is a complex mixture of biologically active compounds that are used to catch prey. In order to evaluate the activity of the neurotoxins in the venom, bioassays were carried out using the marine crab Ocypode quadrata. The proteins with neurotoxic effect were partially purified using low-pressure liquid chromatography techniques. Gel filtration (Sephadex G-50M) was used as the first step and the active fraction in crabs was passed through a QAE Sephadex A-25 column. Finally, the active fraction was run onto a Fractogel EMD SO3- column. No further purification step could be carried out due to the loss of neurotoxic activity. The Fractogel EMD SO3- fraction was analyzed electrophysiologically using the voltage-clamp technique in Xenopus laevis oocytes expressing membrane proteins from rat brain through mRNA injection. The crude venom and a fraction were observed to affect crustaceans and showed at least two types of bioactivity in oocytes expressing brain proteins. The effects were dose-dependent and completely reversible. These results evidence the presence of neurotoxins in Carybdea marsupialis venom that act on membrane proteins of the vertebrate nervous system.

New records of sea anemones (Cnidaria, Anthozoa, Actiniaria) in the Mexican Caribbean

The species Homostichanthus duerdeni and Anemonia sargassensis are recorded for the first time in the Mexican Caribbean. Homostichanthus duerdeni is taxonomically diagnosed, and images from living specimens, including external and internal features and cnidae, are provided. The extension of the geographical distribution range of A. sargassensis is discussed, as well as the taxonomic status of the previous records of actiniarians in the Mexican Caribbean. An updated list of sea anemones in the region is provided, comprising 15 species in 11 localities along the Mexican Caribbean.

Figure 11 In First Inventory Of Sea Anemones (Cnidaria: Actiniaria) Of The Mexican Caribbean

FIGURE 11. — Ragactis lucida. (A) Live specimen in natural habitat. (B) Oral view