Gian Luigi Mariottini

Cnidaria constitute an important phylum of venomous animals, several of which have a significant impact on human health and activities. Cnidarian venoms are included in a special capsule called nematocyst, and are known to consist of peptides, proteins, phospholipids, glycoproteins, sterols, bioactive amines and carbohydrates. Cnidarian venoms are used for hunting and defence, and have paralytic, neurotoxic, cytotoxic, dermotoxic and hemolytic effects on other living organisms. In this study, the neurological and behavioural effects of different doses of venom obtained from the nematocysts of Alicia mirabilis and Aurelia aurita were observed on blue crabs (Callinectes sapidus) individuals. For this purpose, various doses of venoms were injected on the linkage between merus and carpus parts of the cheliped of blue crab individuals. The most common effects of A. mirabilis and A. aurita venoms were observed to be stiffness and trembling behavior in the legs. These symptoms indicate that venom causes neural paralytic syndrome. It has been observed that the effect of venom increases with time and paralysis occurs before death.

The venom contained within cnidarian nematocysts has a complex composition and holds significant potential for biotechnological applications. In this context, one of the most effective methods for studying nematocyst contents is the proteomic approach, which can detect even trace amounts of compounds while minimizing the need for large-scale animal collection, thus helping to preserve ecosystem integrity. This study aimed to provide a comprehensive proteomic and biochemical characterization of the crude nematocyst extract from the common hydrozoan Velella velella. Despite not being harmful to humans, the analysis of the crude venom extract from V. velella brought to the identification of 783 different proteins, categorized into structural components, enzymes, and potential toxins, revealing a qualitative composition of the venom similar to that of other more toxic cnidarians. Biochemical assays confirmed the presence of various active hydrolytic enzymes within the extract, including proteases, phospholipases, hyaluronidases, DNases, and chitinases. These findings pave the road for future studies involving the pharmacological applications of Velella velella venom components through recombinant production and functional testing.

Cnidarian toxins are stored mostly in small capsules (nematocysts) located in tentacles and elsewhere in the body; they are important for the ecology of aquatic environments and also for their impact on some human activities and health, in particular where species lethal for humans live. Though studies about toxic properties of Cnidaria started in the early twentieth century, leading to the formulation of anaphylaxis, an input to the researches on toxic Mediterranean species was given, only during the late '70s, with the occurrence of jellyfish blooms.

The colonization of a substratum by microbes is a survival strategy that allows them to adapt to the variations of environmental conditions and to get nutritive substances. In fact, all marine substrata, including the planktonic organisms, can easily be colonized by bacteria. […]

The authors report about the association of progressive external ophthalmoplegia, atypical pigmentary retinopathy, ataxia phenotype with onset in first months of life (Kearns-Sayre syndrome) and with optic nerve atrophy and deafness. The localization of retinal lesions was coincident with that reported by multifunctional electroretinogram (mfERG) in OPA 1 mutation. The authors hypothesize that Kearns-Sayre mitochondrial mutation may be associated with OPA 1 missense mutation, with worsening of symptomatology, as occurs in the reported case. The prolonged rehabilitation and treatment with coenzyme Q10 for many years gave positive results, with amelioration of ophthalmoplegia, stopping of aggravation of retinal damage and optic nerve atrophy, maintaining of vision some meters away, possibility of socialization and proprioceptive ability amelioration.

The authors report on a patient with Chiari I malformation associated to Waardenburg phenotype, multiple malformations, osteochondrodysplasia and microdeletion of 1q21,1 chromosome, of which they underline the rarity. The pathogenesis connected to the features of neural crest cells-derived structures with mesodermal-derived tissues, mainly in the facial and boundary region of malformed posterior cranial fossa, is discussed. The authors hypothesize that chromosomal microdeletion, acting directly or on contiguous gene(s) or by long range control of gene expression, have modified the function of some developmental genes, causing consequently the association of symptoms observed in the patient.

Introduction: The potential efficacy of selected plant extracts to counteract the dermal toxicity of jellyfish envenomation was investigated using an in vitro cell culture model. Methods: We studied plant extracts from Carica papaya, Ananas comosus, and Bouvardia ternifolia, known for their antivenom properties, in pairwise combinations with tissue homogenates of the jellyfish Pelagia noctiluca, Phyllorhiza punctata, and Cassiopea andromeda, to evaluate modulations of jellyfish cytotoxic effects. L929 mouse fibroblasts were incubated with pairwise jellyfish/plant extract combinations and examined by MTT assay (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide). Results: C papaya and A comosus significantly lowered the cytotoxicity of P noctiluca and P punctata but induced a slight worsening of C andromeda cytotoxicity. Conversely, B ternifolia was protective against P punctata, ineffective against P noctiluca, and worsened C andromeda cytotoxicity. Conclusions: Data showed species-specific and contrasting effects of plant extracts, suggesting that those containing protease activities, namely A comosus and C papaya, are more effective in lowering the cytotoxicity of jellyfish venom containing toxic peptidic factors such as phospholipase A. However, all examined plants require further investigation in vivo to evaluate their ability to counteract jellyfish injury to the skin.

Some species of Cnidarians, well known venomous organisms, are able to induce serious health problems as well as economic and social trouble. A lot of data show that cnidarian venoms can be cytotoxic to cultured cells. Therefore, a priority of the research is to find tools which could counteract the damaging activity of venoms. In this connection, the modulatory effects exerted by extracts of plants Ananas comosus (L.) and Carica papaya (L.) on cytotoxicity of heterotrichous microbasic eurytele nematocysts isolated from the jellyfish Pelagia noctiluca was evaluated. The nematocyst extract induced strong cytotoxicity at highest tested doses with reduction of cell survival below 40% and IC50 value of 40x10(3) nematocysts/mL. Both plant extracts significantly improved the survival of cells, so that the IC50 resulted 74 x 10(3) and 100 x 10(3) nematocysts/mL in the presence of A. comosus and C. papaya extracts, respectively, both used at 10 and 100 mu g/mL. Taking into account that heterotrichous microbasic eurytele nematocysts are present mainly in tentacles, which Pelagia noctiluca utilizes both for predation and defence, this result is particularly interesting from both ecological and sanitary point of view and demonstrates the potential of these plants extracts against cnidarian venoms.

The authors discuss the association of papilledema with Chiari I malformation (CMI) and syringomyelia on the basis of a clinical case studied by radiology, immunology and biochemistry methods. In the presence of normal haematology, blood immunology and biochemistry, clinical signs of headache and papilledema associated to hemifacial asymmetry, blind neck fistulas, malformed ears and spinal abnormalities (symptoms of oculo-auricolo- vertebral spectrum - OAVS), were observed. Magnetic resonance images and computed tomography demonstrated the occurrence of lowered cerebellar tonsils, but with values lower than those typical of the CMI syndrome and syringomyelia. The authors concluded for a minor form (benign ectopia) in the CMI syndrome, associated to papilledema and syringomyelia, and hypothesize an unique pathogenetic mechanism for this complex, connected to neural crest cell development and to OAVS, as extension of this spectrum. The authors underline the relevance of the facial/neck lateral signs for the diagnosis of OAVS associated to brain stem pathology and CMI.