Karyotype Conservation in 2 Populations of the Parthenogenetic Scorpion Tityus serrulatus (Buthidae): rDNA and Its Associated Heterochromatin Are Concentrated on Only One Chromosome

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Supersensitivity of the isolated guinea-pig vas deferens induced by a toxic fraction of scorpion venom (Tityus serrulatus)

1. Tityustoxin (TsTx), a toxic fraction of Tityus serrulatus venom, was studied on the isolated guinea-pig vas deferens. It increased significantly the maximal response of the preparation to both norepinephrine and acetylcholine and decreased the effective median dose of norepinephrine. 2. The effect of TsTx on norepinephrine median dose was unchanged when atropinized or pharmacologically 'denervated' preparations were used but was abolished when both procedures were associated. 3. Atropinization of pharmacologically denervated muscles almost never modify the TsTx-induced increase in the maximal response to norepinephrine. 4. On denervated or phentolamine-treated muscles TsTx-induced increase in the maximal response to acetylcholine was abolished. 5. It was concluded that toxin predominantly induces adrenergic postsynaptic supersensitivity. 6. Of minor significance, it also induces presynaptic cholinergic and adrenergic supersensitivity. 7. Comparison of these results with those of crude venom indicates that TsTx effects may result from the sum of the effects of subcomponents not demonstrated by the chemical procedures here utilized.

Programa de controle de surto de escorpião Tityus serrulatus, Lutz e Mello 1922, no município de Aparecida, SP (Scorpiones, Buthidae).

A scorpion control program was proposed for the town of Aparecida (SP), an endemic region of Tityus serrulatus. Clusters of scorpions in urban and rural areas, environmental degradation of the town's outskirts and new scorpion procreation and dispersal habitats were studied. In addition, infrastructure problems such as the disposal and collection of residential and municipal refuse, sanitation (sewage and storm sewer), condition of vacant lots and constructions in the urban area were evaluated. After an epidemiological study, educational measures such as the distribution of pamphlets, cleaning group work, visits to residences and cooperation from High School teachers and students were also suggested. Chemical control was indicated in high-risk sites, especially those of near-school buildings. Furthermore, the use of natural predators was also mentioned within the present sanitation regulations for urban areas. The authors assert that these procedures must be integrated and continued uninterruptedly for several years. They also suggest a collaborative work with those responsible for the dengue eradication program, as well as the institution of the scorpion study week, which would greatly contribute to the education of the population, to preventive programs and to scorpion control.

Selection of environmental temperature by the yellow scorpion Tityus serrulatus Lutz & Mello, 1922 (Scorpiones, Buthidae)

The preferred temperature of the yellow scorpion Tityus serrulatus was investigated since its dispersion is a matter of concern. Adult T. serrulatus, weighing 1.24 ± 0.20 g (mean + sd) and with a standard length of 59.3 ± 2.5 mm, were used. A metallic corridor (120 cm long, 5 cm large and 10 cm high) with thermal gradient ranging from 0°C to 40°C was used. Tityus serrulatus chose and stayed in temperatures ranging from 14° C to 38°C when safe conditions were offered (dark and thigmotactic stimuli). The number of animals that remained in the 11°C-20°C, 21°C-30°C, and 31°C-40°C temperature zones were 8, 8, and 9, respectively. The chi-square test (degree of freedom = 2) showed that differences were not significant (p>0.05). Some animals moved to lower temperature areas (less than 8°C) when the corridor was completely illuminated and thigmotactic stimuli were absent, which led the animals to present a torpor state. It is concluded that T. serrulatus does not select a specific environmental temperature. Associated with the capacity of temporally surviving at low temperatures, this species seems to be highly adaptable to different thermal zones.

Isolation, homology modeling and renal effects of a C-type natriuretic peptide from the venom of the Brazilian yellow scorpion (Tityus serrulatus)

Mammalian natriuretic peptides (NPs) have been extensively investigated for use as therapeutic agents in the treatment of cardiovascular diseases. Here, we describe the isolation, sequencing and tridimensional homology modeling of the first C-type natriuretic peptide isolated from scorpion venom. In addition, its effects on the renal function of rats and on the mRNA expression of natriuretic peptide receptors in the kidneys are delineated. Fractionation of Tityusserrulatus venom using chromatographic techniques yielded a peptide with a molecular mass of 2190.64Da, which exhibited the pattern of disulfide bridges that is characteristic of a C-type NP (TsNP, T. serrulatus Natriuretic Peptide). In the isolated perfused rat kidney assay, treatment with two concentrations of TsNP (0.03 and 0.1μg/mL) increased the perfusion pressure, glomerular filtration rate and urinary flow. After 60min of treatment at both concentrations, the percentages of sodium, potassium and chloride transport were decreased, and the urinary cGMP concentration was elevated. Natriuretic peptide receptor-A (NPR-A) mRNA expression was down regulated in the kidneys treated with both concentrations of TsNP, whereas NPR-B, NPR-C and CG-C mRNAs were up regulated at the 0.1μg/mL concentration. In conclusion, this work describes the isolation and modeling of the first natriuretic peptide isolated from scorpion venom. In addition, examinations of the renal actions of TsNP indicate that its effects may be related to the activation of NPR-B, NPR-C and GC-C. © 2013 Elsevier Ltd.

Uma abordagem peptidômica do venedo do escorpião Tityus serrulatus

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Clinical aspects of envenomation caused by Tityus obscurus (Gervais, 1843) in two distinct regions of Para state, Brazilian Amazon basin: a prospective case series

Background: Scorpion envenomations are a major public health problem in Brazil, whose most dangerous cases are attributable to the genus Tityus. This study was designed to compare the clinical and demographic features of envenomations by Tityus obscurus in two areas of the state of Para located in the Amazon basin. Were compared demographic findings, local and systemic signs and symptoms of human envenomations caused by T. obscurus that occurred in western and eastern areas of the state.Results: Forty-eight patients with confirmed envenomation by T. obscurus were evaluated from January 2008 to July 2011. Most of them came from the eastern region, where male and female patients were present in similar numbers, while males predominated in the west. Median age groups were also similar in both areas. Most scorpion stings took place during the day and occurred significantly more frequently on the upper limbs. The time between the sting and admission to the health center was less than three hours in both areas. Most eastern patients had local manifestations while in the west, systemic manifestations predominated. Local symptoms were similar in both areas, but systemic signs and symptoms were more common in the west. Symptoms frequently observed at the sting site were local and radiating pain, paresthesia, edema, erythema, sweating, piloerection and burning. The systemic manifestations were significantly higher in patients from the west. Futhermore, neurological symptoms such as general paresthesia, ataxia, dysarthria, myoclonus, dysmetria, and electric shock-like sensations throughout the body were reported only by patients from the west.Conclusion: The present study shows that two regions of Para state differ in the clinical manifestations and severity of confirmed envenomation by T. obscurus which suggests a toxicity variation resulting from the diversity of T. obscurus venom in different areas of the Brazilian Amazon basin, and that T. serrulatus antivenom can be successfully used against T. obscurus.

Agressividade relacionada ao contexto alimentar em escorpião-amarelo Tityus Serrulatus (Lutz & Mello, 1922)(Scorpiones, Buthidae)

Scorpions are among the oldest living groups of animals, and are present in almost every continent. Although many studies are made about the toxins present in their venom, little is known about their behavior. The aim of this paper is to investigate the expression of agressiveness in the brazilian yellow scorpion Tityus serrulatus, specifically the relation between agressiveness, motor activity and feeding condition. The study was divided in two parts. First, we used 16 adult individuals, placed in two terrarium, to establish an ethogram. Each group was observed for 36h, and the behaviors displayed were described and categorized as agonistic or non-agonistic. In the second part of the experiment, we used 32 adult animals in three different nutritional states: Feeding (still ingesting food), Sated (1 to 4 days since last meal) and Deprived (14 to 25 days since last meal). The individuals were paired, each pair placed in a terrarium and observed for 30min. Behaviors displayed were timed in seconds. Our results show that only Feeding individuals displayed agonism towards others, and no relation was observed between motor activity and feeding conditions

Mitotic and meiotic chromosomes of Tityus mattogrossensis and Tityus silvestris (Scorpiones, Buthidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

General characterization of Tityus fasciolatus scorpion venom. Molecular identification of toxins and localization of linear B-cell epitopes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Síntese e caracterização de pequenos peptídeos lineares do veneno de Tityus serrulatus (Buthidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo peptídico e determinação do perfil de metabólitos de venenos de escorpiões da família buthidae: Tityus serrulatus, Tityus bahiensis e Tityus obscurus

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Investigation of the relationship between the structure and function of Ts2, a neurotoxin from Tityus serrulatus venom

Scorpion toxins targeting voltage-gated sodium (NaV) channels are peptides that comprise 6076 amino acid residues cross-linked by four disulfide bridges. These toxins can be divided in two groups (a and beta toxins), according to their binding properties and mode of action. The scorpion a-toxin Ts2, previously described as a beta-toxin, was purified from the venom of Tityus serrulatus, the most dangerous Brazilian scorpion. In this study, seven mammalian NaV channel isoforms (rNaV1.2, rNaV1.3, rNaV1.4, hNaV1.5, mNaV1.6, rNaV1.7 and rNaV1.8) and one insect NaV channel isoform (DmNaV1) were used to investigate the subtype specificity and selectivity of Ts2. The electrophysiology assays showed that Ts2 inhibits rapid inactivation of NaV1.2, NaV1.3, NaV1.5, NaV1.6 and NaV1.7, but does not affect NaV1.4, NaV1.8 or DmNaV1. Interestingly, Ts2 significantly shifts the voltage dependence of activation of NaV1.3 channels. The 3D structure of this toxin was modeled based on the high sequence identity (72%) shared with Ts1, another T. serrulatus toxin. The overall fold of the Ts2 model consists of three beta-strands and one a-helix, and is arranged in a triangular shape forming a cysteine-stabilized a-helix/beta-sheet (CSa beta) motif.

Serrumab: A human monoclonal antibody that counters the biochemical and immunological effects of Tityus serrulatus venom

In Brazil, the species Tityus serrulatus is responsible for the most severe cases of scorpion envenomation. There is currently a need for new scorpion anti-venoms that are more effective and less harmful. This study attempted to produce human monoclonal antibodies capable of inhibiting the activity of T. serrulatus venom (TsV), using the Griffin.1 library of human single-chain fragment-variable (scFv) phage antibodies. Four rounds of phage antibody selection were performed, and the round with the highest phage antibody titer was chosen for the production of monoclonal phage antibodies and for further analysis. The scFv 2A, designated serrumab, was selected for the production and purification of soluble antibody fragments. In a murine peritoneal macrophage cell line (J774.1), in vitro assays of the cytokines interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, and IL-10 were performed. In male BALB/c mice, in vivo assays of plasma urea, creatinine, aspartate transaminase, and glucose were performed, as well as of neutrophil recruitment and leukocyte counts. It was found that serrumab inhibited the TsV-induced increases in the production of IL-6, TNF alpha, and IL-10 in J774.1 cells. The in vivo inhibition assay showed that serrumab also prevented TsV-induced increases in the plasma levels of urea, creatinine, aspartate transaminase, and glucose, as well as preventing the TsV-induced increase in neutrophil recruitment. The results indicate that the human monoclonal antibody serrumab is a candidate for inclusion in a mixture of specific antibodies to the various toxins present in TsV. Therefore, serrumab shows promise for use in the production of new anti-venom.