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Among other scorpion species, Colombia has two genera of the Buthidae family Centruroides and Tityus, considered to be dangerous to humans. This research shares scientific knowledge aiming to a better understanding about the pathophysiological effects of such venoms. The venom of the three species: Centruroides margaritarus, Tityus pachyurus, and T. n. sp. aff. metuendus with biomedical interest were studied. An initial pre-glycemic sample was taken from ICR mice. They were later intraperitoneally inoculated with doses of 35% and 70% of LD50 of total venom. Poisoning signs were observed during a 6-h period to determine the level of scorpionism. After observation, a second glycemic sample was taken, and a histopathological evaluation of different organs was performed. This work revealed that all three venoms showed considerably notorious histopathological alterations in main organs such as heart and lungs, and inducing multiple organ failure, in relation to the glycemia values, only C. margaritatus and T. n. sp. aff. metuendus showed significant changes through manifestation of hyperglycemia. According to the Colombian scorpionism level, signs were mild to severe affecting the autonomous nervous system.

The Colombian scorpion Centruroides margaritatus produces a venom considered of low toxicity. Nevertheless, there are known cases of envenomation resulting in cardiovascular disorders, probably due to venom components that target ion channels. Among them, the humanether-à-go-go-Related gene (hERG1) potassium channels are critical for cardiac action potential repolarization and alteration in its functionality are associated with cardiac disorders. This work describes the purification and electrophysiological characterization of a Centruroides margaritatus venom component acting on hERG1 channels, the CmERG1 toxin. This novel peptide is composed of 42 amino acids with a MW of 4792.88 Da, folded by four disulfide bonds and it is classified as member number 10 of the γ-KTx1 toxin family. CmERG1 inhibits hERG1 currents with an IC50 of 3.4 ± 0.2 nM. Despite its 90.5% identity with toxin ɣ-KTx1.1, isolated from Centruroides noxius, CmERG1 completely blocks hERG1 current, suggesting a more stable plug of the hERG channel, compared to that formed by other ɣ-KTx.

The Colombian scorpion Centruroides margaritatus produces a venom considered of low toxicity. Nevertheless, there are known cases of envenomation resulting in cardiovascular disorders, probably due to venom components that target ion channels. Among them, the human ether-à-go-go-Related gene (hERG1) potassium channels are critical for cardiac action potential repolarization and alteration in its functionality are associated with cardiac disorders. This work describes the purification and electrophysiological characterization of a Centruroides margaritatus venom component acting on hERG1 channels, the CmERG1 toxin. This novel peptide is composed of 42 amino acids with a MW of 4792.88 Da, folded by four disulfide bonds and it is classified as member number 10 of the γ-KTx1 toxin family. CmERG1 inhibits hERG1 currents with an IC50 of 3.4 ± 0.2 nM. Despite its 90.5% identity with toxin ɣ-KTx1.1, isolated from Centruroides noxius, CmERG1 completely blocks hERG1 current, suggesting a more stable plug of the hERG channel, compared to that formed by other ɣ-KTx.

Centruroides margaritatus es una especie de escorpión causante de escorpionismo moderado en humanos con síntomas clínicos de envenenamiento que resultan en algunos casos en trastornos cardiovasculares. La fracción cromatográfica II del veneno, correspondiente a péptidos con masas moleculares entre 2500 y 6000 Da, en un ensayo in vivo en ratas experimentales, causó alteraciones hemodinámicas en la presión arterial media sistémica, la presión y el volumen ventricular de eyección, la actividad del sistema de conducción cardiaco y el inotropismo. El veneno total de este escorpión ejerció un efecto beta en los canales hNav1.1, hNav1.2, hNav1.3, hNav1.5 y hNav1.6, un efecto alfa débil en los canales hNav1.7 y un efecto alfa y beta en el canal hNav1.4; bloqueó además los canales de potasio hKv1.1 y Kv11.1 y redujo débilmente las corrientes hKv1.4, pero no modificó las corrientes hEAG1 y hKv7.1. Del veneno se aislaron e identificaron dos nuevas toxinas: la primera denominada CmERG1, es un péptido de 42 residuos de aminoácidos y masa molecular de 4792.88 Da, ocho cisteínas en su secuencia para cuatro enlaces disulfuro, miembro 10 de la familia de toxinas γ-KTx1, el cual bloqueó completamente las corrientes hERG1 de manera reversible, con IC50 de 3.4 ± 0.2 nM, presentó una identidad de 90.5% con la toxina ɣ-KTx1.1 una hERGTx aislada del escorpión Centruroides noxius. La segunda toxina denominada Cm2ERG1, es un péptido con 37 residuos de aminoácidos masa molecular de 3980 Da, 6 cisteinas en su secuencia para tres puentes disulfuro, el cual bloqueó parcialmente las corrientes hERG de manera reversible en dosis de 500 μM, se clasifica como un α-KTx con identidad del 97,3% con un péptido putativo obtenido por transcriptomica de la glándula de veneno del escorpión C. hentzi. Se determinó además el efecto vasomotor de las toxinas CmERG1, Cm2ERG1, y de la toxina MgTx presente en el veneno de este escorpión así como de una mezcla de péptidos de las subfracciones FII6-10, en anillos aórticos de rata aislados en cámara de órganos. La toxina CmERG2 tuvo efecto vasoconstrictor en anillos íntegros y en anillos libres de endotelio, MgTx tuvo efecto vasoconstrictor en anillos libres de endotelio, CmERG1 y FII6-10 no tuvieron efecto vasoconstrictor, ninguna de las cuatro toxinas evaluadas presentó efecto vasodilatador. Doctorado DOCTOR(A) EN CIENCIAS BIOMÉDICAS

Resumen Centrutoides margaritatus es uno de los escorpiones más comunes en Costa Rica, pese a esto en este país no se han realizado estudios ecológicos ni poblacionales. Por lo tanto, se pretendió caracterizar el uso del hábitat y actividad superficial de esta especie en el Parque Nacional Palo Verde. El muestreo de los escorpiones se realizó mediante búsqueda intensiva a lo largo de transectos en tres sitios: carretera, campamento y bosque. Se caracterizó el microhábitat en el cual se encontraba cada individuo y se observó la actividad superficial que estaban realizando los escorpiones en el momento de la captura. C. margaritatus se encontró en diferentes microhábitats: suelo, hojarasca, herbáceas, arbustos, árboles, y debajo de rocas y troncos caídos, con una preferencia a utilizar la vegetación a alturas menores a 50 cm. El acecho fue el comportamiento más frecuente y fue observado mayormente en la vegetación, mientras que el descanso se encontró principalmente en troncos y rocas caídas. El uso de la vegetación puede representar una estrategia para obtener alimento y asimismo estar en un sitio seguro contra depredadores. A pesar de esto, la adaptabilidad que presenta la especie le provee la facilidad de usar muchos microhábitats en sitios donde la vegetación es escaza. Aunque el periodo de estudio fue corto, este estudio arroja las primeras observaciones acerca del uso del hábitat de esta especie en Costa Rica, información base para futuras investigaciones. AbstractCentruroides margaritatus is one of the most common scorpions in Costa Rica, however almost null ecological or population-based studies have been conducted. Therefore, the objective of the present study was to characterize the habitat use and surface activity of this species in Palo Verde National Park, Costa Rica. Scorpions were searched intensively along transects at three sites: road, camp and forest. The microhabitat in each capture was characterized and the surface activity of the scorpions was recorded at the time of capture. C. margaritatus was found in different microhabitats: soil, leaf litter, herbaceous plants, shrubs, trees, and under rocks and fallen logs, with a preference to use vegetation to heights less than 50 cm. The scorpions were in an ambush behavior most of the times and were observed mostly in the vegetation, while they were in a resting behavior mainly under fallen trunks and rocks. The use of vegetation can represent a strategy to obtain food and also be in a safe place against predators. Nevertheless, the species adaptability provides the ease of using many microhabitats in sites where vegetation is scarce. While the study period was short, this research provides the first observations about the habitat use of this species in Costa Rica, which serves as a basis for future investigation.

Teruel, Rolando, Roncallo, César A. (2010): Rare or poorly known scorpions from Colombia. IV. Additions, synonymies and new records (Scorpiones: Buthidae, Scorpionidae). Euscorpius 105 (105): 1-15, DOI: 10.18590/euscorpius.2010.vol2010.iss105.1, URL: https://mds.marshall.edu/euscorpius/vol2010/iss105/1/

The presence in rural areas of western Ecuador of scorpions in the genus Tityus capable of producing pediatric mortality is hereby evidenced. The medical significance of scorpions in Ecuador has been underestimated partly because of the clinically unimportant stings delivered by Centruroides margaritatus and Teuthraustes atramentarius, which have venom with low toxicity to vertebrates. Five intra-domiciliary cases of scorpion envenoming in victims aged between 1.9 and 16 years old, including one fatality, are reported from rural settings in forest areas of Chone (n = 2) and Flavio Alfaro (n = 3) counties, northern Manabi province, western Ecuador. Three cases were graded as Class II (moderate) and two in Class III (severe) envenoming. Manifestations showed characteristic autonomic nervous system hyper-stimulation and the fatality (a 1.9-year-old boy from Flavio Alfaro) was due to cardio-respiratory failure. Marked leukocytosis in four of the cases (21,800-31,800 cells/mm(3)), with notable neutrophilia (58-82%), suggests induction of a venom-mediated systemic inflammatory response-like syndrome. Specimens responsible for cases in Flavio Alfaro County, including the fatality, were classified as Tityus asthenes Pocock, accountable for severe scorpionism in Colombia. These findings demand implementation of control and therapeutic measures in affected areas in Ecuador, including evaluation of available scorpion antivenoms.

Centruroides margaritatus (Gervais, 1841) Figs. 1, 10 Centruroides gracilis: G��mez & Otero, 2007: 56; fig. 4a (misidentification). New Records: COLOMBIA, Magdalena Department, Santa Marta city, January 2009, leg. J. A. Vargas, 1 juvenile (Sco-0422). La Guajira Department, Riohacha, Jos�� A. Gal��n District, 8 November 2006, leg. C. A. Roncallo, 1♀ (Sco-0360); Riohacha, Barrio Arriba District, 25 July 2007, leg. C. A. Roncallo, 1♂ (Sco- 0375); Riohacha downtown, 25 June 2008, leg. W. Ramos, 1♂ (Sco-0395), 5 October 2008, leg. C. A. Roncallo, 1 juvenile (Sco-0421); Riohacha graveyard, August 2009, leg. C. A. Roncallo, 1♂ (Sco-0420); Serran��a de Macuira, 3 km west of Nazareth, 14 July 2007, leg. J. Echavarr��a, 1♀ (Sco-0374). Remarks: all specimens recorded herein were collected under different conditions, but always associated to human environments: inside inhabited houses (two specimens from Riohacha and those from Santa Marta and Nazareth), walking on the streets at night (two specimens from Riohacha), and under rock in a sandy beach (one specimen from Riohacha). These Colombian specimens of C. margaritatus match in all diagnostic features the samples studied from other localities throughout Central America and Greater Antilles, with the single exception of the base color of the body and appendages, which is light yellowish with a more contrasting dark pattern. The precise geographical distribution of this species in Colombia is currently unknown. Previously published records must be considered as unreliable, because at least in some cases it has been confused with C. gracilis, as is evident from those papers, which have been supplemented with photographs (i.e., G��mez & Otero, 2007: 56; fig. 4a). These misidentifications could explain why some authors have recorded supposed hybridization between these two species (Louren��o, 1991b) or even doubted about their taxonomic validity (Louren��o, 1997); otherwise, both species are not even closely related and belong to different species-groups (R. Teruel, unpublished data)., Published as part of Teruel, Rolando & Roncallo, C��sar A., 2010, Rare or poorly known scorpions from Colombia. IV. Additions, synonymies and new records (Scorpiones: Buthidae, Scorpionidae), pp. 1-15 in Euscorpius 105 (105) on pages 1-2, DOI: 10.18590/euscorpius.2010.vol2010.iss105.1, http://zenodo.org/record/4649083

Mating behavior in Centruroides margaritatus, as in other scorpion species, includes a series of rapid rocking or shaking movements of the male ("juddering"). It has been suggested that substrate vibrations are generated by juddering and that females respond to them by approaching the male, but its functional significance remains little studied. For the first time, substrate vibrations produced by males during courtship in Centruroides margaritatus are documented. The male started juddering after his first physical contact with the female and only one type of male vibratory signal was registered. The signal is produced during a series of rapid shaking of the male’s body from front to rear and consists of multiple short pulses. Each pulse is called a judder and several judders "a series". The average duration of each judder was 0.018±0.009s (n=50) with an interval of 0.028±0.013s (n=50); the average duration of each series of judders was 4.2±3.5s with an interval between series of 3.5±6.3s and a rate of 0.21±0.17 series per second. The females responded in 72% of the time to the males juddering. Rev. Biol. Trop. 57 (Suppl. 1): 267-274. Epub 2009 November 30.El comportamiento de apareamiento en Centruroides margaritatus como en otras especies del escorpiones, incluye una serie de oscilaciones rápidas hacia adelante y hacia atrás del cuerpo del macho (juddering). Se ha especulado que tales oscilaciones generan vibraciones en el substrato y las hembras pueden responder a ellas aproximándose al macho, pero su significado funcional sigue siendo poco estudiado. Por primera vez, las vibraciones del substrato producidas por los machos durante el comportamiento de cortejo de Centruroides margaritatus son documentadas. El macho comenzó las vibraciones después de su primer contacto físico con la hembra y sólo se registró un tipo de señal vibratoria. La señal se produce durante una serie de rápidas sacudidas del cuerpo del macho de adelante hacia atrás y se compone de múltiples pulsos cortos. La duración media de cada pulso fue 0.018±0.009s (n = 50) con un intervalo de 0.028±0.013s (n=50); la duración media de cada serie de pulsos fue de 4.2±3.5s, con un intervalo entre las series de 3.5±6.3s y una tasa de 0.21±0.17 serie por segundo. Las hembras respondieron en un 72% del tiempo a las sacudidas de los machos. Se discute acerca de su posible función como señal.

Three cases of hybridization obtained in laboratory conditions between Centruroides gracilis and Centruroides margaritatus bring some evidence on the genetic relationship between these two species. The experiments were done with specimens collected in Florida (USA), Mexico and Colombia.

The Number of Teeth of the Pectines as a Variable Character in Centruroides margaritatus (Gervais, 1841) (Scorpiones, Buthidae) The variability of the number of teeth of the pectines is analysed for the Buthidae scorpion Centruroides margaritatus (Gervais, 1841), species described from Puna island in Ecuador. C. margaritatus shows a very important sexual difference for this character. Some statistical calculations are added, confirming the preliminary conclusions.

The toxicology of the common Colombian scorpion Centruroides margaritatus has been studied and venom assays compared with the common Arizonan C. sculpturatus . Twenty-four different clinical symptoms due to the scorpion sting are given. The average LD50-mice dose was found to be 59.9mg/kg body weight. Clinical studies of over 1000 randomly selected people indicated that the scorpion venom is of low toxicity, as could be expected from the venom assays. The most common and important symptoms were pain, local edema and fever 1–20 hr after the sting. There was no evidence of necrosis, permanent mutilation or death. Women, children and people working indoors are stung most frequently, and people of the age group 4–20 years are the most common victims.