RESUMO
BACKGROUND: Today, the use of cellular therapies as an effective treatment in the field of health is increasing. In the COVID-19 pandemic or similar situations, cellular therapies may be sometimes life-saving. The COVID-19 pandemic has shown us that the training of intensive care nurses in special cases, such as cellular therapies, is insufficient. AIM: The study aimed to determine the duties, responsibilities and training of intensive care nurses on mesenchymal stem cells (MSCs) transplantation to critically ill patients during the COVID-19 pandemic. STUDY DESIGN: This descriptive and retrospective study was conducted on 107 critically ill patients diagnosed with COVID-19 infection and followed up in the intensive care unit (ICU) between April 2020 and April 2022. Each patient was transplanted MSCs by intravenous infusion three times. Before starting cellular therapy applications, intensive care nurses were selected to work on this treatment modality. Each nurse was given theoretical and practical training by experienced instructors. RESULTS: Intensive care nurses trained for MSCs transplants took part in the pre-application, preparation, application and post-application period. MSCs were checked by the ICU nurses in the pre-application period. Patients' vital signs, existing catheters, consciousness status and parameters were checked by nurses in the preparation and application period. No side effects and complications were observed in patients during MSCs transplantation and within the first 24 h. Patients' late complications and mortality were recorded by nurses during the post-application periods. CONCLUSIONS: We recommend that nurses working especially in Level 3 ICUs receive training and certification in cellular therapies, especially in hospitals where advanced/cellular treatments are applied. RELEVANCE TO CLINICAL PRACTICE: Intensive care nurses are actively involved in every phase of the application of MSCs. Especially before such special practices, which came to the fore with the COVID-19 pandemic, training should be organized for intensive care nurses.
Assuntos
COVID-19 , Enfermeiras e Enfermeiros , Humanos , Estado Terminal/terapia , Pandemias , Estudos Retrospectivos , Cuidados Críticos , Unidades de Terapia IntensivaRESUMO
Background: Scorpion neurotoxins such as those that modify the mammalian voltage-gated sodium ion channels (Nav) are the main responsible for scorpion envenomation. Their neutralization is crucial in the production of antivenoms against scorpion stings. Methods: In the present study, two in silico designed genes - one that codes for a native neurotoxin from the venom of the Anatolian scorpion Androctonus crassicauda, named Acra 4 - and another non-native toxin - named consensus scorpion toxin (SccTx) obtained from the alignment of the primary structures of the most toxic neurotoxins from the Middle Eastern and North African scorpions - were recombinantly expressed in E. coli Origami. Results: Following bacterial expression, the two expressed neurotoxins, hereafter named HisrAcra4 and HisrSccTx, were obtained from inclusion bodies. Both recombinant neurotoxins were obtained in multiple Cys-Cys isoforms. After refolding, the active protein fractions were identified with molecular masses of 8,947.6 and 9,989.1 Da for HisrAcra4 and HisrSccTx, respectively, which agreed with their expected theoretical masses. HisrAcra4 and HisrSccTx were used as antigens to immunize two groups of rabbits, to produce either anti-HisrAcra4 or anti-HisrSccTx serum antibodies, which in turn could recognize and neutralize neurotoxins from venoms of scorpion species from the Middle East and North Africa. The antibodies obtained from rabbits neutralized the 3LD50 of Androctonus australis, Leiurus quinquestriatus hebraeus and Buthus occitanus venoms, but they did not neutralize A. crassicauda and A. mauritanicus venoms. In addition, the anti-HisrAcra4 antibodies did not neutralize any of the five scorpion venoms tested. However, an antibody blend of anti-HisrAcra4 and anti-HisrSccTx was able to neutralize A. crassicauda and A. mauritanicus venoms. Conclusions: Two recombinant Nav neurotoxins, from different peptide families, were used as antigens to generate IgGs for neutralizing scorpion venoms of species from the Middle East and North Africa.
RESUMO
Venoms have evolved >100 times in all major animal groups, and their components, known as toxins, have been fine-tuned over millions of years into highly effective biochemical weapons. There are many outstanding questions on the evolution of toxin arsenals, such as how venom genes originate, how venom contributes to the fitness of venomous species, and which modifications at the genomic, transcriptomic, and protein level drive their evolution. These questions have received particularly little attention outside of snakes, cone snails, spiders, and scorpions. Venom compounds have further become a source of inspiration for translational research using their diverse bioactivities for various applications. We highlight here recent advances and new strategies in modern venomics and discuss how recent technological innovations and multi-omic methods dramatically improve research on venomous animals. The study of genomes and their modifications through CRISPR and knockdown technologies will increase our understanding of how toxins evolve and which functions they have in the different ontogenetic stages during the development of venomous animals. Mass spectrometry imaging combined with spatial transcriptomics, in situ hybridization techniques, and modern computer tomography gives us further insights into the spatial distribution of toxins in the venom system and the function of the venom apparatus. All these evolutionary and biological insights contribute to more efficiently identify venom compounds, which can then be synthesized or produced in adapted expression systems to test their bioactivity. Finally, we critically discuss recent agrochemical, pharmaceutical, therapeutic, and diagnostic (so-called translational) aspects of venoms from which humans benefit.
Assuntos
Proteômica , Peçonhas , Animais , Pesquisa , Serpentes/genética , Transcriptoma , Peçonhas/química , Peçonhas/genéticaRESUMO
Venom research is a highly multidisciplinary field that involves multiple subfields of biology, informatics, pharmacology, medicine, and other areas. These different research facets are often technologically challenging and pursued by different teams lacking connection with each other. This lack of coordination hampers the full development of venom investigation and applications. The COST Action CA19144-European Venom Network was recently launched to promote synergistic interactions among different stakeholders and foster venom research at the European level.
Assuntos
PeçonhasRESUMO
PURPOSE: This study was conducted to investigate the relationship between nomophobia, fear of missing out (FoMO), and perceived work overload (PWO) among nurses in Turkey. DESIGN AND METHODS: This descriptive study was carried out with 178 nurses. In the study, the Nomophobia Questionnaire, FoMO scale, and PWO scale were used. FINDINGS: There was a positive and significant relationship between nomophobia, FoMO, and PWO variables. The nomophobia and FoMO independent variables accounted for 6% of the PWO-dependent variable. PRACTICE IMPLICATIONS: Controlled use of smartphones and social media can contribute to the minimizing of the work overload perceived by nurses as a time pressure factor.
Assuntos
Enfermeiras e Enfermeiros , Mídias Sociais , Medo , Humanos , Inquéritos e Questionários , TurquiaRESUMO
Broadly-neutralizing monoclonal antibodies are of high therapeutic utility against infectious diseases caused by bacteria and viruses, as well as different types of intoxications. Snakebite envenoming is one such debilitating pathology, which is currently treated with polyclonal antibodies derived from immunized animals. For the development of novel envenoming therapies based on monoclonal antibodies with improved therapeutic benefits, new discovery approaches for broadly-neutralizing antibodies are needed. Here, we present a methodology based on phage display technology and a cross-panning strategy that enables the selection of cross-reactive monoclonal antibodies that can broadly neutralize toxins from different snake species. This simple in vitro methodology is immediately useful for the development of broadly-neutralizing (polyvalent) recombinant antivenoms with broad species coverage, but may also find application in the development of broadly-neutralizing antibodies against bacterial, viral, and parasitic agents that are known for evading therapy via resistance mechanisms and antigen variation.
Assuntos
Anticorpos Monoclonais/química , Anticorpos Neutralizantes/química , Antivenenos/química , Testes de Neutralização , Animais , Antígenos/química , Biotecnologia , Reações Cruzadas/imunologia , Desenho de Fármacos , Ensaio de Imunoadsorção Enzimática , Humanos , Fragmentos Fab das Imunoglobulinas/imunologia , Técnicas In Vitro , Concentração Inibidora 50 , Queratinócitos/imunologia , Espectrometria de Massas , Biblioteca de Peptídeos , Proteômica , Proteínas Recombinantes/química , Serpentes , PeçonhasRESUMO
Toxin synergism is a complex biochemical phenomenon, where different animal venom proteins interact either directly or indirectly to potentiate toxicity to a level that is above the sum of the toxicities of the individual toxins. This provides the animals possessing venoms with synergistically enhanced toxicity with a metabolic advantage, since less venom is needed to inflict potent toxic effects in prey and predators. Among the toxins that are known for interacting synergistically are cytotoxins from snake venoms, phospholipases A2 from snake and bee venoms, and melittin from bee venom. These toxins may derive a synergistically enhanced toxicity via formation of toxin complexes by hetero-oligomerization. Using a human keratinocyte assay mimicking human epidermis in vitro, we demonstrate and quantify the level of synergistically enhanced toxicity for 12 cytotoxin/melittin-PLA2 combinations using toxins from elapids, vipers, and bees. Moreover, by utilizing an interaction-based assay and by including a wealth of information obtained via a thorough literature review, we speculate and propose a mechanistic model for how toxin synergism in relation to cytotoxicity may be mediated by cytotoxin/melittin and PLA2 complex formation.
RESUMO
Scorpion venom may cause severe medical complications and untimely death if injected into the human body. Neurotoxins are the main components of scorpion venom that are known to be responsible for the pathological manifestations of envenoming. Besides neurotoxins, a wide range of other bioactive molecules can be found in scorpion venoms. Advances in separation, characterization, and biotechnological approaches have enabled not only the development of more effective treatments against scorpion envenomings, but have also led to the discovery of several scorpion venom peptides with interesting therapeutic properties. Thus, scorpion venom may not only be a medical threat to human health, but could prove to be a valuable source of bioactive molecules that may serve as leads for the development of new therapies against current and emerging diseases. This review presents both the detrimental and beneficial properties of scorpion venom toxins and discusses the newest advances within the development of novel therapies against scorpion envenoming and the therapeutic perspectives for scorpion toxins in drug discovery.
RESUMO
BACKGROUND: Transcrof toxin genes of scorpion species have been published. Up to this moment, no information on the gene characterization of M. gibbosus is available. RESULTS: This study provides the first insight into gene expression in venom glands from M. gibbosus scorpion. A cDNA library was generated from the venom glands and subsequently analyzed (301 clones). Sequences from 177 high-quality ESTs were grouped as 48 Mgib sequences, of those 48 sequences, 40 (29 "singletons" and 11 "contigs") correspond with one or more ESTs. We identified putative precursor sequences and were grouped them in different categories (39 unique transcripts, one with alternative reading frames), resulting in the identification of 12 new toxin-like and 5 antimicrobial precursors (transcripts). The analysis of the gene families revealed several new components categorized among various toxin families with effect on ion channels. Sequence analysis of a new KTx precursor provides evidence to validate a new KTx subfamily (α-KTx 27.x). A second part of this work involves the genomic organization of three Meg-chlorotoxin-like genes (ClTxs). Genomic DNA sequence reveals close similarities (presence of one same-phase intron) with the sole genomic organization of chlorotoxins ever reported (from M. martensii). CONCLUSIONS: Transcriptome analysis is a powerful strategy that provides complete information of the gene expression and molecular diversity of the venom glands (telson). In this work, we generated the first catalogue of the gene expression and genomic organization of toxins from M. gibbosus. Our result represents a relevant contribution to the knowledge of toxin transcripts and complementary information related with other cell function proteins and venom peptide transcripts. The genomic organization of the chlorotoxin genes may help to understand the diversity of this gene family.
Assuntos
Genoma , Venenos de Escorpião/genética , Escorpiões/genética , Transcriptoma , Sequência de Aminoácidos , Animais , DNA Complementar , Dados de Sequência Molecular , Venenos de Escorpião/química , Homologia de Sequência de AminoácidosRESUMO
Abstract In this study, protease-producing capacity of Bacillus pumilus D3, isolated from hydrocarbon contaminated soil, was evaluated and optimized. Optimum growing conditions for B. pumilus D3 in terms of protease production were determined as 1% optimum inoculum size, 35 °C temperature, 11 pH and 48 h incubation time, respectively. Stability studies indicated that the mentioned protease was stable within the pH range of 7-10.5 and between 30 °C and 40 °C temperatures. Surprisingly, the activity of the enzyme increased in the presence of SDS with concentration up to 5 mM. The protease was concentrated 1.6-fold with ammonium sulfate precipitation and dialysis. At least six protein bands were obtained from dialysate by electrophoresis. Four clear protein bands with caseinolytic activity were detected by zymography. Dialysate was further purified by anion-exchange chromatography and the caseinolytic active fraction showed a single band between 29 and 36 kDa of reducing conditions.
Assuntos
Bacillus/enzimologia , Proteínas de Bactérias/química , Endopeptidases/química , Microbiologia do Solo , Bacillus/química , Bacillus/genética , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/isolamento & purificação , Endopeptidases/biossíntese , Endopeptidases/isolamento & purificação , Estabilidade Enzimática , Expressão Gênica , Concentração de Íons de Hidrogênio , Cinética , Dodecilsulfato de Sódio/química , TemperaturaRESUMO
Constitutes of the venom scorpion are a rich source of low molecular mass peptides which are toxic to various organisms, including man. Androctonus crassicauda is one of the scorpions from the Southeastern Anatolia of Turkey with public health importance. This work is focused on the investigation of biological effects of Acra3 peptide from Androctonus crassicauda. For this purpose, Acra3 isolated from crude venoms was tested for its cytotoxicity on BC3H1 mouse brain tumor cells using tetrazolium salt cleavage and lactate dehydrogenase activity assays. To determine whether the cytotoxic effects of Acra3 was related to the induction of apoptosis, the morphology of the cells and the nuclear fragmentation was examined by using Acridin Orange staining and DNA fragmentation assay, respectively. Caspase 3 and caspase 9 activities were measured spectrophotometrically and flow cytometric assay was performed using Annexin-V FITC and Propidium Iodide staining. Furthermore toxic peptide Acra3 was used as an antigen for immunological studies. Results showed that Acra3 exerted very strong cytotoxic effect on BC3H1 cells with an IC50 value of 5 µg/ml. Exposure of the cells to 0.1 and 0.5 µg/ml was resulted in very strong appearance of the apoptotic morphology in a dose dependent manner. On the other side, not any DNA fragmentation was observed after treatment of the cells. Caspase 3 and 9 activities were slightly decreased with Acra3. Results from flow cytometry and lactate dehydrogenase activity assays indicate that Acra3 exerts its effects by inducing a stronger necrosis than apoptosis in BC3H1 cells. To evaluate its immunogenicity, monoclonal antibody (MAb) specific for Acra3 antigen (5B9) was developed by hybridoma technology using spleen and lymph nodes of mice and immunoglobulin type of antibody was found to be IgM. We suggest that Acra3 may exert its effects by inducing both necrotic and apoptotic pathway in some way on mouse brain tumor cells. These findings will be useful for understanding the mechanism of cell death caused by venom in vitro. Anti-Acra3 monoclonal antibody can be further used as a bioactive tools for exploring the structure/function relationship and the pharmacological mechanism of scorpion peptide neurotoxins.
Assuntos
Proteínas de Artrópodes/farmacologia , Venenos de Escorpião/química , Animais , Anticorpos Monoclonais/biossíntese , Proteínas de Artrópodes/isolamento & purificação , Neoplasias Encefálicas , Caspase 3/metabolismo , Caspase 9/metabolismo , Linhagem Celular Tumoral , Fragmentação do DNA/efeitos dos fármacos , Citometria de Fluxo , Imunoglobulina M/biossíntese , Linfonodos/efeitos dos fármacos , Linfonodos/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Necrose/induzido quimicamente , Peptídeos/farmacologia , Baço/efeitos dos fármacos , Baço/imunologiaRESUMO
Due to the medical importance played in Turkey by stings of the scorpion Androctonus crassicauda, its venom has been studied with more attention. In this communication we report a new toxic peptide, named Acra4, because it is the fourth peptide completely characterized from venom of this scorpion. The peptide contains 64 amino acid residues stabilized by four disulfide bridges, with a molecular weight of 6937 Da. Purification of the lethal peptide was performed by three steps of high performance liquid chromatography (HPLC) separations, and the molecular weight was determined by mass spectrometry analysis and the full amino acid sequence was obtained by direct Edman degradation in conjunction with gene cloning. The LD50 of Acra4 was 50.5 ng/20 g mouse body weight (95% confidence intervals from 48.8 to 52.2 ng/20 g mouse body weight). Additionally, from a sample of cDNA of A. crassicauda four genes were cloned displaying sequence similarities to known scorpion toxins, and are reported here as potentially toxic peptides, named Acra5 to Acra8. Electrophysiological studies of Acra4 were performed using Na(+)-channels expressed in F11 cell culture, by patch-clamp recordings. This is the first time that such peptide from A. crassicauda having a specific Na(+)-channel α-type effect is reported. Its affinity toward Na(+)-channels in F11 cell line is in the order of 1 µM concentration.
Assuntos
Venenos de Escorpião/química , Venenos de Escorpião/toxicidade , Sequência de Aminoácidos , Animais , Cromatografia Líquida de Alta Pressão , Clonagem Molecular , Camundongos , Dados de Sequência Molecular , Técnicas de Patch-Clamp , Peptídeos/química , Peptídeos/isolamento & purificação , Peptídeos/toxicidade , Receptores Nicotínicos/efeitos dos fármacos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Venenos de Escorpião/isolamento & purificação , EscorpiõesRESUMO
AIM: To report a study conducted using a qualitative and quantitative study pattern with an aim to reveal the perceptions of in-service training nurses about in-service training nurses via metaphors. BACKGROUND: The in-service training nurse assumes great responsibility in the effective and efficient implementation of the educational activities in healthcare. In line with this, determining the perceptions of the in-service training nurses about in-service training nurses via metaphors and taking this into consideration in professional activities are important in terms of developing, changing, or questioning the perspectives of the in-service training nurses about their roles and developing their own training nurse identity. DESIGN: This article was designed as qualitative and quantitative study pattern. METHODS: The population of the study included 93 in-service training nurses. Data were collected between June-September 2009. To collect data, each in-service training nurse was asked to complete the blanks in the sentence, 'The in-service training nurse is like a/an.....................because..................' The data were analysed using qualitative (content analysis) and quantitative (chi-square) data analysis methods. FINDINGS: According to the findings of the study, the in-service training nurses identified 59 metaphors in total. The metaphors were grouped under nine conceptual categories depending on the characteristics they had in common. In cognitive image of the in-service training nurses relating to the concept of in-service training nurse, the outstanding conceptual category was the in-service training nurse as a knowledge provider. CONCLUSION: The metaphors can be used as a strong research tool in understanding, revealing and explaining the cognitive images of the in-service training nurses.
Assuntos
Educação em Enfermagem/métodos , Capacitação em Serviço/métodos , Metáfora , Adulto , Atitude do Pessoal de Saúde , Feminino , Humanos , Masculino , Percepção , TurquiaRESUMO
In the present study, we report for the first time, the molecular, biochemical and electrophysiological characterization of the components present in the soluble venom from Mesobuthus gibbosus (Brullé, 1832). According to the epidemiological and clinical situation of scorpion envenomation cases M. gibbosus scorpion is one of the most important health-threatening species of Turkey. Despite the medical importance reported for M. gibbosus, there is no additional information on toxin peptides and venom components to clarify the toxic effect of the M. gibbosus sting. Biochemical characterization of the venom was performed using different protocols and techniques following a bioassay-guided strategy (HPLC, mass spectrometry and Edman degradation sequencing). Venom fractions were tested in electrophysiological assays on a panel of six K(+) channels (K(v)1.1-1.6) by using the two-electrode voltage clamp technique. Three new α-KTx peptides were found and called MegKTx1, MegKTx2 and MegKTx3 (M. gibbosus, K(+) channel toxin number 1-3). A cDNA library from the telson was constructed and specific screening of transcripts was performed. Biochemical and molecular characterization of MegKTx peptides and transcripts shows a relation with toxins of three different α-KTx subfamilies (α-KTx3.x, α-KTx9.x and α-KTx16.x).
Assuntos
Bloqueadores dos Canais de Potássio/farmacologia , Venenos de Escorpião/farmacologia , Escorpiões/química , Sequência de Aminoácidos , Animais , Cromatografia Líquida de Alta Pressão , Clonagem Molecular , DNA Complementar/genética , Dados de Sequência Molecular , Oócitos , Técnicas de Patch-Clamp , Peptídeos/farmacologia , Bloqueadores dos Canais de Potássio/química , Venenos de Escorpião/química , Turquia , XenopusRESUMO
Androctonus crassicauda is one of the Southeastern Anatolian scorpions of Turkey with ethno-medical and toxicological importance. Two toxic peptides (Acra1 and Acra2) were isolated and characterized from the venom of this scorpion. In this communication, the isolation of an additional toxin (Acra3) by chromatographic separations (HPLC and TSK-gel sulfopropyl) and its chemical and functional characterization is reported. Acra3 is a 7620Da molecular weight peptide, with 66 amino acid residues crosslinked by four disulfide bridges. The gene coding for this peptide was cloned and sequenced. Acra3 is anticipated to undergo post-translational modifications at the C-terminal region, having an amidated serine as last residue. Injection of Acra3 induces severe neurotoxic events in mice, such as: excitability and convulsions, leading to the death of the animals within a few minutes after injection. Electrophysiological assays conducted with pure Acra3, using cells that specifically expressed sodium channels (Nav1.1-Nav1.6) showed no clear effect. The exact molecular target of Acra3 remained undiscovered, similar to three other scorpion peptides that clustered very closely in the phylogenetic tree included here. The exact target of these four peptides is not very clear.
Assuntos
Peptídeos/genética , Venenos de Escorpião/genética , Escorpiões/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Linhagem Celular , Cromatografia de Fase Reversa , Clonagem Molecular , Sequência Conservada , Crustáceos , DNA Complementar/genética , DNA Complementar/isolamento & purificação , Gryllidae , Humanos , Dose Letal Mediana , Potenciais da Membrana/efeitos dos fármacos , Camundongos , Dados de Sequência Molecular , Peptídeos/isolamento & purificação , Peptídeos/farmacologia , Peptídeos/toxicidade , Filogenia , Venenos de Escorpião/isolamento & purificação , Venenos de Escorpião/farmacologia , Venenos de Escorpião/toxicidade , Análise de Sequência de DNA , Homologia de Sequência de AminoácidosRESUMO
To evaluate chronic ethanol toxicity on erythrocyte membrane and preventive action of betaine as a methyl donor, 24 male Wistar albino rats were divided into three groups: control, ethanol and ethanol plus betaine group. Animals were fed 60 ml diet per day for two months. Rats in the ethanol group were fed ethanol 8 g/kg/day. The ethanol + betaine groups were fed ethanol plus betaine (0.5% w/v). After two months, all animals were killed. Malondialdehyde (MDA) and sialic acid (SA) levels were determined in plasma samples. Osmotic fragility tests were performed on whole blood samples and erythrocyte membrane thiol contents were determined using membrane suspensions. Plasma MDA levels in ethanol-given rats were increased significantly compared to the control group of rats (p < 0.05). MDA in the betaine group was significantly lower than that in the ethanol group (p < 0.05). Erythrocyte membrane thiol contents in ethanol group were decreased compared with those of the control group (p < 0.05). Thiol contents were increased slightly after betaine therapy, but this increase was not statistically significant (p > 0.05). Plasma sialic acid levels in the ethanol group were significantly higher than in the control group (p < 0.05). Sialic acid was decreased in the betaine group compared to the ethanol group (p < 0.05). In the osmotic fragility test, we observed that chronic ethanol consumption increased erythrocyte hemolysis. Betaine protected against ethanol-induced hemolysis. Our findings show that chronic ethanol administration affects erythrocyte membrane properties and this may be related to oxidative stress. Betaine protects erythrocyte membrane alterations against chronic ethanol toxicity. Therefore betaine as a nutritional agent, may protect ethanol induced clinical problems associated with membrane abnormalities.
Assuntos
Betaína/farmacologia , Membrana Eritrocítica/efeitos dos fármacos , Membrana Eritrocítica/metabolismo , Etanol/farmacologia , Ácido N-Acetilneuramínico/sangue , Animais , Masculino , Malondialdeído/sangue , Pressão Osmótica , Oxirredução , Ratos , Ratos WistarRESUMO
The soluble venom from the scorpion Androctonus crassicauda was fractionated by high performance liquid chromatography. At least 44 different sub-fractions were resolved and collected for finger print mass analysis using an electrospray mass spectrometer. This analysis revealed the presence of 80 distinct molecular mass components, from which five were further characterized. A peptide, named Acra1 was fully sequenced. It contains 58 amino acid residues cross-bridged by six cysteines forming three disulfide pairs, with a molecular mass of 6497 Da. A second purified peptide named Acra2 was partially sequenced with a molecular mass of 7849 Da. Acra1 is toxic and Acra2 is lethal to mice, at the dose assayed. Additionally, a cDNA library of the venomous gland of one specimen was prepared and several clones were obtained among which is one that codes for Acra1. Three analog gene sequences were found with point mutations either in the section that corresponds to the mature peptide or to the signal peptide. The signal peptide is 22 amino acid residues long. Several other gene sequences obtained suggest the presence in this venom of three distinct groups of peptides, among which are peptides similar to known Na(+)-channel specific toxins of other scorpions. A new type of peptide was identified with odd number of cysteines (seven), allowing the formation of heterodimers with molecular masses in the range of 16,000 atomic mass units (a.m.u.).