Gene cloning, heterologous expression and activity identification of latroeggtoxin-Ⅵ / 生物工程学报

One of the distinct characters of Latrodectus tredecimguttatus is that its toxic components exist not only in the venomous glands, but also in the tissues outside the venomous glands and even in the eggs. Investigation on the toxins outside the venomous glands can deepen our understanding of spider toxins and discover new lead molecules with important application prospects. In order to explore the low-abundance proteinaceous toxins in the L. tredecimguttatus eggs, we used bioinformatic strategies to mine a gene sequence encoding a peptide toxin from the transcriptome of L. tredecimguttatus eggs, and then heterologously expressed the gene successfully with a 3'-RACE combined with nest PCR strategy. Biological activity analyses indicated that the expressed peptide toxin, named latroeggtoxin-Ⅵ (LETX-Ⅵ), could inhibit Na⁺ channel currents in ND7/23 cells and promote dopamine release from PC12 cells, without obvious toxicity against Periplaneta americana and bacteria as well as fungi including Staphylococcus aureus and Candida albicans, demonstrating that LETX-Ⅵ is a mammal-specific neurotoxin with a potential application prospect in development of the tool reagents for neurobiological study and the drugs for treating related diseases.

Latrodectismo. Caso clínico y revisión de la literatura / Latrodectism Case report and review of literature

El latrodectismo es un cuadro clínico causado por la mordedura de una araña del género Latrodectus spp., ampliamente distribuido en todo Chile continental. Generalmente las mordeduras se asocian a faenas agrícolas. El veneno del género Latrodectus contiene α-latrotoxina, una neurotoxina que actúa a nivel presináptico del sistema nervioso autónomo aumentando la liberación de acetilcolina. El cuadro clínico es inespecífico y hasta en un tercio de los casos ocurren síntomas sistémicos. El diagnóstico es clínico y depende del antecedente de la mordedura por una araña con un cuadro clínico compatible. El pronóstico es favorable: se reporta una letalidad entre 0 y 6 por ciento. El manejo es esencialmente sintomático, principalmente analgésico. Presentamos el caso de un hombre de 62 años, proveniente de Santa Cruz, VI región, trabajador en una plantación de trigo. Consultapor dolor torácico asociado a mialgias generalizadas y diaforesis. Por sospecha de latrodectismo, se administra neostigmina con buena respuesta clínica.(AU)

Latrodectism is a clinical entity caused by the bite of a spider of the genus Latrodectus spp. widely distributed throughout continental Chile. Generally, bites are associated with agricultural activities. The venom of spiders of the genus Latrodectus contains α-latrotoxin, a neurotoxin that acts at the presynaptic level of the autonomic nervous system, this way increases the release of acetylcholine. The clinical manifestations are non-specific and systemic symptoms occur in up to one-third of the cases. The diagnosis is clinical and depends on the history of being bitten by a spider with a compatible clinical presentation. The prognosis is favorable: a lethality between 0 and 6 percent has been reported. The clinical management is essentially symptomatic, mainly analgesic. We present the case of a 62-year-old man from Santa Cruz, VI region, working in a wheat farm. He attends the emergency service with chest pain associated with generalized myalgias and diaphoresis. On suspicion of latrodectism, neostigmine is administered with goodclinical response. (AU)

Physiological and biochemical characterization of egg extract of black widow spiders to uncover molecular basis of egg toxicity

BACKGROUND: Black widow spider (L. tredecimguttatus) has toxic components not only in the venomous glands, but also in other parts of the body and its eggs. It is biologically important to investigate the molecular basis of the egg toxicity. RESULTS: In the present work, an aqueous extract was prepared from the eggs of the spider and characterized using multiple physiological and biochemical strategies. Gel electrophoresis and mass spectrometry demonstrated that the eggs are rich in high-molecular-mass proteins and the peptides below 5 kDa. The lyophilized extract of the eggs had a protein content of 34.22% and was shown to have a strong toxicity towards mammals and insects. When applied at a concentration of 0.25 mg/mL, the extract could completely block the neuromuscular transmission in mouse isolated phrenic nerve-hemidiaphragm preparations within 12.0 ± 1.5 min. Using whole-cell patch-clamp technique, the egg extract was demonstrated to be able to inhibit the voltage-activated Na+, K+and Ca2+ currents in rat DRG neurons. In addition, the extract displayed activities of multiple hydrolases. Finally, the molecular basis of the egg toxicity was discussed. CONCLUSIONS: The eggs of black widow spiders are rich in proteinous compounds particularly the high-molecular-mass proteins with different types of biological activity The neurotoxic and other active compounds in the eggs are believed to play important roles in the eggs' toxic actions.

Envenenamiento en niños por mordedura de la araña Latrodectus Mactans (Viuda Negra): características clínicas y tratamiento / Poisoning caused by Latrodectus Mactans (Black Widow) spider bite among children: clinical features and therapy

Introducción: El envenenamiento por mordedura de araña viuda negra es poco frecuente en edades pediátricas sin embargo no está exento de complicaciones y si no se trata a tiempo puede causar la muerte. En México se desconoce el número exacto de estos accidentes. Objetivo: Identificar los signos y síntomas característicos, evolución y tratamiento de los niños atendidos por morderua de araña en el Hospital Infantil del Estado de Sonora, con el propósito de establecer el tratamiento oportuno. Material y Métodos: Se revisaron 43 expedientes de niños hospitalizados por mordedura de araña viuda negra entre 1978-2004, las variables consideradas fueron: edad, género, lugar de origen, sitio del accidente, área corporal afectada, tratamiento previo; grado de envenenamiento por signos y síntomas, tratamiento, evolución clínica. Resultados: Predominó el género masculino 69.7%; sin diferencias entre el número de menores de seis años, escolares y adolescentes. El 44 y 37% de los casos se presentaron en el verano y en horas de la tarde, respectivamente. El 74% de los pacientes tuvieron el contacto con el arácnido dentro del domicilio; las áreas anatómicas más afectadas fueron, miembros superiores y tronco; los signos y síntomas más notables en lactantes y preescolares fueron: irritabilidad, llanto constante, sialorrea, agitación, eritema en área de lesión convulsiones. En escolares y adolescentes fueron los signos y sínotmas dolor en sitio de lesión, dolor abdominal, dolor torácico, ansiedad, espasmos musculares y temblor fino. Los pacientes que recibieron tratamiento con faboterapia específica tuvieron mejor evolución y menor tiempo de hospitalización, cabe señalar que no se presentó mortalidad. Conclusiones: La adecuada identificación de los signos y síntomas ocasionados por la morderura de araña en lactantes y preescolares permite el diagnóstico oportuno y ofrece la mejor alternativa de tratamiento.

INTRODUCTION: Poisoning caused by black widow spider bite, is not commonly observed during childhood, it is not exempt from complications, and must be treated in time or the patient can die. In Mexico we do not have accurate data on the exact number of accidents due to this condition. OBJECTIVE: Identify the signs and characteristic symptoms of children treated at the Children's Hospital from the state of Sonora with the aim of starting early treatment. MATERIAL AND METHODS: We reviewed 43 clinical records of hospitalized patients admitted for black widow spider bite between 1978 - 2004. Demographic variables were: age, gender, place of origin, place where accident took place, treatment given prior to hospital admittance, degree of envenomation measured by signs and symptoms, treatment and clinical evolution. RESULTS: 69.7% of cases were male, we did not find differences in the number of patients between infant, pre-school, elementary school children and teenagers. During summer and afternoon hours we registered 44% and 37% cases respectively; 74% patients were poisoned by the spider at home; the anatomical areas most affected were: arms, hands and thorax. Signs and symptoms in infants were: irritability, constanty cry, sialorrea, agitation erythema on wounded areas and seizures. Among elementary school children and teenagers signs included pain in wounded area, abdominal and thoracic, muscle spasms, fine tremor and residual signs. Patients who received fabotherapic treatment had better evolution and less time of hospitalization. No deaths were reported. CONCLUSIONS: The different signs and symptoms between infants, preschool, elementary school children and teenagers allowed us to clearly identify evenommation and differentiate it form confounding diseases. In our study, specific fabotherapy constituted the best treatment choice.

Aracnoidismo sistémico

Se reportan 4 casos de picaduras por arañas compatibles con el tipo viuda negra, en pacientes adultos de la provincia de Ciego de Ávila. Los síntomas y signos sobresalientes fueron: parestesias, vómitos, sudación, cólicos abdominales, adinamia e hipotensión. Los pacientes fueron tratados fundamentalmente con hidrocortisona endovenosa y administración de volumen. La evolución fue satisfactoria y rápida, con recuperación al cuarto día.

4 cases of spider bites, which are compatile with the black widow type were reported in adult patients from the province of Ciego de Avila. The most important symptoms and signs were: paresthesia, vomits, sweating, abdominal colics, acratia and hypotension. The evolution was satisfactory and fast. Patients recovered on the fourth day.