Recombinant expression and antigenicity of two peptide families of neurotoxins from Androctonus sp

Background: Scorpion neurotoxins such as those that modify the mammalian voltagegated 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.(AU)

Exposure to 50 Hz electromagnetic field changes the efficiency of the scorpion alpha toxin

Background Extremely low-frequency (50 Hz) electromagnetic field (ELF-EMF) is produced by electric power transmission lines and electronic devices of everyday use. Some phenomena are proposed as "first effects" of ELF-EMF: the discrete changes in the membrane potential and the increase of the calcium channel activity as well as the intracellular concentration of Ca 2+ . Interaction of the scorpion alpha toxin with the sodium channel depends on the orientation of the charges and may be perturbed by changes in the membrane polarization. The toxin induces overexcitability in the nervous system and an increase in the neurotransmitters released with different consequences, mainly the paralysis of muscles. We assumed that the exposure to ELF-EMF 0.7 mT will change the effects of the insect selective scorpion alpha toxin (recombinant LqhαIT from Leiurus quinquestriatus hebraeus) at the level of the cercal nerve function, the synaptic transmission and on the level of entire insect organism. Taking into account the compensatory mechanisms in organisms, we tested in addition ten times higher ELF-EMF on whole insects.Methods Experiments were performed in vivo on cockroaches (Periplaneta americana) and in vitro - on isolated cockroach abdominal nerve cord with cerci. In biotests, the effects of LqhαIT (10 −8 M) were estimated on the basis of the insect ability to turn back from dorsal to ventral side. Three groups were compared: the control one and the two exposed to ELF-EMF - 0.7 and 7 mT. Bioelectrical activity of the cercal nerve and of the connective nerve that leaves the terminal abdominal ganglion was recorded using extracellular electrodes. LqhαIT (5 × 10 −8 M) induced modifications of neuronal activity that were observed in the control cockroach preparations and in the ones exposed to ELF-EMF (0.7 mT). The exposure to ELF-EMF was carried out using coils with a size appropriate to the examined objects.Results The exposure to ELF-EMF (0.7 mT) modified the effects of LqhαIT (5 × 10−8 M) on activity of the cercal nerve and of the connective nerve. We observed a decrease of the toxin effect on the cercal nerve activity, but the toxic effect of LqhαIT on the connective nerve was increased. Biotests showed that toxicity of LqhαIT (10 −8 M) on cockroaches was reduced by the exposure to ELF-EMF (0.7 and 7 mT).Conclusions The exposure to 50 Hz ELF-EMF modified the mode of action of the anti-insect scorpion alpha toxin LqhαIT at cellular level of the cockroach nervous system and in biotests. Toxin appeared as a usefull tool in distinguishing between the primary and the secondary effects of ELF-EMF.(AU)

Exposure to 50 Hz electromagnetic field changes the efficiency of the scorpion alpha toxin

Background Extremely low-frequency (50 Hz) electromagnetic field (ELF-EMF) is produced by electric power transmission lines and electronic devices of everyday use. Some phenomena are proposed as first effects of ELF-EMF: the discrete changes in the membrane potential and the increase of the calcium channel activity as well as the intracellular concentration of Ca 2+ . Interaction of the scorpion alpha toxin with the sodium channel depends on the orientation of the charges and may be perturbed by changes in the membrane polarization. The toxin induces overexcitability in the nervous system and an increase in the neurotransmitters released with different consequences, mainly the paralysis of muscles. We assumed that the exposure to ELF-EMF 0.7 mT will change the effects of the insect selective scorpion alpha toxin (recombinant LqhIT from Leiurus quinquestriatus hebraeus) at the level of the cercal nerve function, the synaptic transmission and on the level of entire insect organism. Taking into account the compensatory mechanisms in organisms, we tested in addition ten times higher ELF-EMF on whole insects.Methods Experiments were performed in vivo on cockroaches (Periplaneta americana) and in vitro on isolated cockroach abdominal nerve cord with cerci. In biotests, the effects of LqhIT (10 8 M) were estimated on the basis of the insect ability to turn back from dorsal to ventral side. Three groups were compared: the control one and the two exposed to ELF-EMF 0.7 and 7 mT. Bioelectrical activity of the cercal nerve and of the connective nerve that leaves the terminal abdominal ganglion was recorded using extracellular electrodes. LqhIT (5 × 10 8 M) induced modifications of neuronal activity that were observed in the control cockroach preparations and in the ones exposed to ELF-EMF (0.7 mT). The exposure to ELF-EMF was carried out using coils with a size appropriate to the examined objects.Results The exposure to ELF-EMF (0.7 mT) modified the effects of LqhIT (5 × 108 M) on activity of the cercal nerve and of the connective nerve. We observed a decrease of the toxin effect on the cercal nerve activity, but the toxic effect of LqhIT on the connective nerve was increased. Biotests showed that toxicity of LqhIT (10 8 M) on cockroaches was reduced by the exposure to ELF-EMF (0.7 and 7 mT).Conclusions The exposure to 50 Hz ELF-EMF modified the mode of action of the anti-insect scorpion alpha toxin LqhIT at cellular level of the cockroach nervous system and in biotests. Toxin appeared as a usefull tool in distinguishing between the primary and the secondary effects of ELF-EMF.(AU)

Exposure to 50 Hz electromagnetic field changes the efficiency of the scorpion alpha toxin

Background Extremely low-frequency (50 Hz) electromagnetic field (ELF-EMF) is produced by electric power transmission lines and electronic devices of everyday use. Some phenomena are proposed as first effects of ELF-EMF: the discrete changes in the membrane potential and the increase of the calcium channel activity as well as the intracellular concentration of Ca 2+ . Interaction of the scorpion alpha toxin with the sodium channel depends on the orientation of the charges and may be perturbed by changes in the membrane polarization. The toxin induces overexcitability in the nervous system and an increase in the neurotransmitters released with different consequences, mainly the paralysis of muscles. We assumed that the exposure to ELF-EMF 0.7 mT will change the effects of the insect selective scorpion alpha toxin (recombinant LqhIT from Leiurus quinquestriatus hebraeus) at the level of the cercal nerve function, the synaptic transmission and on the level of entire insect organism. Taking into account the compensatory mechanisms in organisms, we tested in addition ten times higher ELF-EMF on whole insects.Methods Experiments were performed in vivo on cockroaches (Periplaneta americana) and in vitro on isolated cockroach abdominal nerve cord with cerci. In biotests, the effects of LqhIT (10 8 M) were estimated on the basis of the insect ability to turn back from dorsal to ventral side. Three groups were compared: the control one and the two exposed to ELF-EMF 0.7 and 7 mT. Bioelectrical activity of the cercal nerve and of the connective nerve that leaves the terminal abdominal ganglion was recorded using extracellular electrodes. LqhIT (5 × 10 8 M) induced modifications of neuronal activity that were observed in the control cockroach preparations and in the ones exposed to ELF-EMF (0.7 mT). The exposure to ELF-EMF was carried out using coils with a size appropriate to the examined objects.Results The exposure to ELF-EMF (0.7 mT) modified the effects of LqhIT (5 × 108 M) on activity of the cercal nerve and of the connective nerve. We observed a decrease of the toxin effect on the cercal nerve activity, but the toxic effect of LqhIT on the connective nerve was increased. Biotests showed that toxicity of LqhIT (10 8 M) on cockroaches was reduced by the exposure to ELF-EMF (0.7 and 7 mT).Conclusions The exposure to 50 Hz ELF-EMF modified the mode of action of the anti-insect scorpion alpha toxin LqhIT at cellular level of the cockroach nervous system and in biotests. Toxin appeared as a usefull tool in distinguishing between the primary and the secondary effects of ELF-EMF.

Dangerous scorpion fauna of Mali

Although the main Malian scorpion species of medical interest, Androctonus amoreuxi, is responsible for severe envenomings and perhaps some deaths, it has hitherto been considered not dangerous for humans. This population is located in the Saharian North-Eastern regions of Mali where it is accompanied by Leiurus quinquestriatus, a well known dangerous species of the Sahara. In the Gao district, divided by the Niger River, less desolate than the Tessalit and Kidal regions, one specimen of the dangerous species Androctonus australis was found. To summarize, Mali harbors at least three dangerous scorpion species: Leiurus quinquestriatus, Androctonus amoreuxi and A. australis, the latter recently having been identified in Mali for the first time. The absence of Androctonus aeneas is surprising in this context because it is found in neighboring countries (Algeria, Niger) and should be detected by new surveys. The possibility of preparing a single scorpion antivenom intended for Saharian and sub-Saharian populations is discussed.(AU)

Dangerous scorpion fauna of Mali

Although the main Malian scorpion species of medical interest, Androctonus amoreuxi, is responsible for severe envenomings and perhaps some deaths, it has hitherto been considered not dangerous for humans. This population is located in the Saharian North-Eastern regions of Mali where it is accompanied by Leiurus quinquestriatus, a well known dangerous species of the Sahara. In the Gao district, divided by the Niger River, less desolate than the Tessalit and Kidal regions, one specimen of the dangerous species Androctonus australis was found. To summarize, Mali harbors at least three dangerous scorpion species: Leiurus quinquestriatus, Androctonus amoreuxi and A. australis, the latter recently having been identified in Mali for the first time. The absence of Androctonus aeneas is surprising in this context because it is found in neighboring countries (Algeria, Niger) and should be detected by new surveys. The possibility of preparing a single scorpion antivenom intended for Saharian and sub-Saharian populations is discussed.(AU)

A newly described scorpion species, Leiurus abdullahbayrami (Scorpion: Buthidae), and the lethal potency and in vivo effects of its venom

Currently, medically significant scorpion species belong to the Buthidae family and are represented by the genera Androctonus, Buthus, Mesobuthus, Hottentotta, Parabuthus, Tityus, Centruroides, Leiurus. Although Leiurus was originally considered a monotypic genus, four additional species have since been described. Leiurus abdullahbayrami (previously identified as L. quinquestriatus in Turkey) was classified as a new Leiurus species. This is the first report conducted on the lethality and biologic effects of L. abdullahbayrami scorpion venom in mice. In this study, the electrophoretic protein pattern of its venom was also determined. Two protein bands with molecular masses of 4 and 6 kDa were more strongly detected than other protein bands in the venom sample. Electrophoresis showed that L. abdullahbayrami scorpion venom possesses both short- and long-chain neurotoxins. The median lethal dose of this venom was found to be 0.19 mg/kg by subcutaneous (SC) injection in mice. Animals experimentally envenomed with L. abdullahbayrami venom exhibited hyperexcitability, agitation, aggressive behavior, squeaking and fighting, tachypnea, weakness, convulsions, and death due to cardiac and respiratory failure. In further studies, the potency of antivenom should be investigated in relation to the scorpion venom. Molecular and pharmacological studies are also required to identify and characterize L. abdullahbayrami scorpion venom.(AU)

A newly described scorpion species, Leiurus abdullahbayrami (Scorpion: Buthidae), and the lethal potency and in vivo effects of its venom

Currently, medically significant scorpion species belong to the Buthidae family and are represented by the genera Androctonus, Buthus, Mesobuthus, Hottentotta, Parabuthus, Tityus, Centruroides, Leiurus. Although Leiurus was originally considered a monotypic genus, four additional species have since been described. Leiurus abdullahbayrami (previously identified as L. quinquestriatus in Turkey) was classified as a new Leiurus species. This is the first report conducted on the lethality and biologic effects of L. abdullahbayrami scorpion venom in mice. In this study, the electrophoretic protein pattern of its venom was also determined. Two protein bands with molecular masses of 4 and 6 kDa were more strongly detected than other protein bands in the venom sample. Electrophoresis showed that L. abdullahbayrami scorpion venom possesses both short- and long-chain neurotoxins. The median lethal dose of this venom was found to be 0.19 mg/kg by subcutaneous (SC) injection in mice. Animals experimentally envenomed with L. abdullahbayrami venom exhibited hyperexcitability, agitation, aggressive behavior, squeaking and fighting, tachypnea, weakness, convulsions, and death due to cardiac and respiratory failure. In further studies, the potency of antivenom should be investigated in relation to the scorpion venom. Molecular and pharmacological studies are also required to identify and characterize L. abdullahbayrami scorpion venom.(AU)

In vivo and in vitro effects of scorpion venoms in Turkey: a mini-review

Scorpion stings constitute a common type of accident in Turkey due to the geographic location, climate and socioeconomic structure of this country. Moreover, envenomation cases are considered a public health problem throughout Turkey. Based on data in the literature, the main clinical features of scorpion envenomations are defined as systemic manifestations including sweating, hypertension and vomiting, and among prominent causes of death are cardiorespiratory manifestations, toxic myocarditis and pulmonary edema. The most important health-threatening scorpions found in Turkey are: Androctonus crassicauda, Leiurus quinquestriatus, Mesobuthus gibbosus and Mesobuthus eupeus, all of which belong to the Buthidae family. This study indicates that there is no data related to venom toxicity and in vivo effects of other scorpions found in Turkey - such as Mesobuthus caucasicus, Mesobuthus nigrocinctus and Hottentotta saulcyi - and that further research should be performed to determine their health effects.(AU)

In vivo and in vitro effects of scorpion venoms in Turkey: a mini-review

Scorpion stings constitute a common type of accident in Turkey due to the geographic location, climate and socioeconomic structure of this country. Moreover, envenomation cases are considered a public health problem throughout Turkey. Based on data in the literature, the main clinical features of scorpion envenomations are defined as systemic manifestations including sweating, hypertension and vomiting, and among prominent causes of death are cardiorespiratory manifestations, toxic myocarditis and pulmonary edema. The most important health-threatening scorpions found in Turkey are: Androctonus crassicauda, Leiurus quinquestriatus, Mesobuthus gibbosus and Mesobuthus eupeus, all of which belong to the Buthidae family. This study indicates that there is no data related to venom toxicity and in vivo effects of other scorpions found in Turkey - such as Mesobuthus caucasicus, Mesobuthus nigrocinctus and Hottentotta saulcyi - and that further research should be performed to determine their health effects.(AU)

Notes on gestation periods and litter size in the arenicolous buthid scorpion Leiurus quinquestriatus (Ehrenberg, 1828) (Scorpiones: Buthidae)

The following notes on gestation periods and litter size in seven specimens of Leiurus quinquestriatus are presented as observational data. Specimens of Leiurus quinquestriatus from southern Egypt and southern Israel were mated in the laboratory during 2007; afterwards, gestation periods and litter sizes of all females were recorded. Previous studies on this species reported that the gestation period ranged from 150 to 155 days and that litter size was between 12 and 99 offspring. In the present study, gestation periods in specimens from both geographic regions varied from 155 to 227 days and litter sizes were between 35 and 87 offspring. The current contribution expands on previously published data on gestation periods and supports previously reported litter size in Leiurus quinquestriatus.

Notes on gestation periods and litter size in the arenicolous buthid scorpion Leiurus quinquestriatus (Ehrenberg, 1828) (Scorpiones: Buthidae)

The following notes on gestation periods and litter size in seven specimens of Leiurus quinquestriatus are presented as observational data. Specimens of Leiurus quinquestriatus from southern Egypt and southern Israel were mated in the laboratory during 2007; afterwards, gestation periods and litter sizes of all females were recorded. Previous studies on this species reported that the gestation period ranged from 150 to 155 days and that litter size was between 12 and 99 offspring. In the present study, gestation periods in specimens from both geographic regions varied from 155 to 227 days and litter sizes were between 35 and 87 offspring. The current contribution expands on previously published data on gestation periods and supports previously reported litter size in Leiurus quinquestriatus.(AU)

New additions to the scorpion fauna of Riyadh region, Saudi Arabia

In this work, we present additional morphological data about the scorpion fauna of Saudi Arabia. This investigation was carried out in the central region (Riyadh) of the country and identified existing and newly discovered scorpion species for taxonomic documentation while determining the medically important ones. The survey covered the entire Riyadh region, including all major districts, and collected a total of 4,164 specimens. Morphological identification of collected animals was based on identification keys. There were two species (one with a subspecies) that belonged to the family Scorpionidae, namely Scorpio maurus kruglovi (0.02 percent) and Hemiscorpius arabicus (0.05 percent). The latter, currently, is part of the Hemiscorpiidae family that had been upgraded from a subfamily. Eight more species from the Buthidae family were found: Leiurus quinquestriatus (7.20 percent), Androctonus crassicauda (17.24 percent), Androctonus bicolor (64.60 percent), Compsobuthus arabicus (3.84 percent), Compsobuthus werneri (0.94 percent), Buthacusyotvatensis nigroaculeatus (2.31 percent), Buthacusleptochelys (3.24 percent) and Orthochirus innesi (0.55 percent). The major locations of collection were the outskirts of Riyadh city and the airport vicinity. The specimens were transported from all central region areas in 124 short trips.(AU)

New additions to the scorpion fauna of Riyadh region, Saudi Arabia

In this work, we present additional morphological data about the scorpion fauna of Saudi Arabia. This investigation was carried out in the central region (Riyadh) of the country and identified existing and newly discovered scorpion species for taxonomic documentation while determining the medically important ones. The survey covered the entire Riyadh region, including all major districts, and collected a total of 4,164 specimens. Morphological identification of collected animals was based on identification keys. There were two species (one with a subspecies) that belonged to the family Scorpionidae, namely Scorpio maurus kruglovi (0.02 percent) and Hemiscorpius arabicus (0.05 percent). The latter, currently, is part of the Hemiscorpiidae family that had been upgraded from a subfamily. Eight more species from the Buthidae family were found: Leiurus quinquestriatus (7.20 percent), Androctonus crassicauda (17.24 percent), Androctonus bicolor (64.60 percent), Compsobuthus arabicus (3.84 percent), Compsobuthus werneri (0.94 percent), Buthacusyotvatensis nigroaculeatus (2.31 percent), Buthacusleptochelys (3.24 percent) and Orthochirus innesi (0.55 percent). The major locations of collection were the outskirts of Riyadh city and the airport vicinity. The specimens were transported from all central region areas in 124 short trips.(AU)

Evaluation of the neutralizing capacity of Androctonus crassicauda (Olivier, 1807) antivenom against Leiurus quinquestriatus (Ehrenberg, 1928) venom (Scorpiones: Buthidae)

The two most venomous species of the family Buthidae, Leiurus quinquestriatus and Androctonus crassicauda, are found in Africa and in the Middle East. Potency and paraspecific activities of A. crassicauda antivenom (RSHC anti-Ac) were tested against L. quinquestriatus venom. The sera produced by Refik Saydam Hygiene Center (RSHC) showed strong reactivity against the venoms of A. crassicauda and L. quinquestriatus in western blotting and dot-blot analysis. RSHC anti-Ac presents immunoactivity and neutralizing potential against Leiurus quinquestriatus venom. Neutralization capacity of antivenom was found to be 400 µL against 40 minimum lethal doses (MLD) of A. crassicauda scorpion venom and 10 MLD of L. quinquestriatus venom. This study indicates that the RSHC anti-Ac could be used for treating L. quinquestriatus stings.

Evaluation of the neutralizing capacity of Androctonus crassicauda (Olivier, 1807) antivenom against Leiurus quinquestriatus (Ehrenberg, 1928) venom (Scorpiones: Buthidae)

The two most venomous species of the family Buthidae, Leiurus quinquestriatus and Androctonus crassicauda, are found in Africa and in the Middle East. Potency and paraspecific activities of A. crassicauda antivenom (RSHC anti-Ac) were tested against L. quinquestriatus venom. The sera produced by Refik Saydam Hygiene Center (RSHC) showed strong reactivity against the venoms of A. crassicauda and L. quinquestriatus in western blotting and dot-blot analysis. RSHC anti-Ac presents immunoactivity and neutralizing potential against Leiurus quinquestriatus venom. Neutralization capacity of antivenom was found to be 400 µL against 40 minimum lethal doses (MLD) of A. crassicauda scorpion venom and 10 MLD of L. quinquestriatus venom. This study indicates that the RSHC anti-Ac could be used for treating L. quinquestriatus stings.(AU)

Evaluation of scorpion sting incidence in turkey

Scorpion stings are common in Turkey due to its geographical location, climate and socioeconomic structure. Scorpion envenomation cases are a considerable public health problem in all regions of the country. Important health-threatening scorpions in Turkey are Androctonus crassicauda, Leiurus quinquestriatus, Mesobuthus gibbosus and M. eupeus, all of which belong to the Buthidae family. They are described to be potentially dangerous to humans. So far, there is no study about scorpion sting incidence covering all geographical regions of Turkey; therefore, in this study, we analyzed the frequency of scorpion sting cases in the country. A total of 24,261 scorpion sting cases were reported during 2005. Most of which (about 80%) occurred in the Southeastern Anatolia (30.4%), Mediterranean Sea (24.9%) and Aegean regions (23.5%), where medically important scorpion species are found. The sting cases mostly occurred during the summer period. Our results suggest that scorpion stings are an important problem in Turkey. This simple descriptive study will help develop interventions to prevent scorpion stings, which should take local sting cases into consideration.

Evaluation of scorpion sting incidence in turkey

Scorpion stings are common in Turkey due to its geographical location, climate and socioeconomic structure. Scorpion envenomation cases are a considerable public health problem in all regions of the country. Important health-threatening scorpions in Turkey are Androctonus crassicauda, Leiurus quinquestriatus, Mesobuthus gibbosus and M. eupeus, all of which belong to the Buthidae family. They are described to be potentially dangerous to humans. So far, there is no study about scorpion sting incidence covering all geographical regions of Turkey; therefore, in this study, we analyzed the frequency of scorpion sting cases in the country. A total of 24,261 scorpion sting cases were reported during 2005. Most of which (about 80%) occurred in the Southeastern Anatolia (30.4%), Mediterranean Sea (24.9%) and Aegean regions (23.5%), where medically important scorpion species are found. The sting cases mostly occurred during the summer period. Our results suggest that scorpion stings are an important problem in Turkey. This simple descriptive study will help develop interventions to prevent scorpion stings, which should take local sting cases into consideration.

Evaluation of scorpion sting incidence in turkey

Scorpion stings are common in Turkey due to its geographical location, climate and socioeconomic structure. Scorpion envenomation cases are a considerable public health problem in all regions of the country. Important health-threatening scorpions in Turkey are Androctonus crassicauda, Leiurus quinquestriatus, Mesobuthus gibbosus and M. eupeus, all of which belong to the Buthidae family. They are described to be potentially dangerous to humans. So far, there is no study about scorpion sting incidence covering all geographical regions of Turkey; therefore, in this study, we analyzed the frequency of scorpion sting cases in the country. A total of 24,261 scorpion sting cases were reported during 2005. Most of which (about 80 percent) occurred in the Southeastern Anatolia (30.4 percent), Mediterranean Sea (24.9 percent) and Aegean regions (23.5 percent), where medically important scorpion species are found. The sting cases mostly occurred during the summer period. Our results suggest that scorpion stings are an important problem in Turkey. This simple descriptive study will help develop interventions to prevent scorpion stings, which should take local sting cases into consideration.(AU)

Morphological identification of scorpion species from Jazan and Al-Medina Al-Munawara regions, Saudi Arabia

The present work is a complementary contribution to the comprehensive study of the scorpion sting syndrome in Saudi Arabia. It deals with the identification and determination of medically important scorpions and the other ones, which were collected from two regions (Jazan and Al-Medina Al-Munawara), based on their morphology (the molecular phylogeny and venom characteristics will appear in subsequent publications). The specimens collected from those two regions were brought to the Research Center laboratories in several batches. Morphological identification of the collected specimens was done employing identification keys. There were 646 specimens collected from Jazan Region. A single species, Nebo hierichonticus (Family Diplocentridae), and five genera with four identified species, Parabuthus liosoma, Hottentotta jayakari (salei?), Compsobuthus werneri, Leiurus quinquestriatus (Vachoniolus globimanus?), Vachoniolus spp. (other species) and Orthochirus innesi (Family Buthidae), were classified as extant scorpions in the region. Three hundred and ninety-six specimens from Al-Medina Al-Munawara Region were categorized into eight groups; four of them were identified. Three buthids, Leiurus quinquestriatus, Androctonus crassicauda, Orthochirus innesi and one scorpion specimen, Scorpio maurus, were identified and classified as extant scorpions in this region. The other four species are still not completely identified. They are Vachoniolus (Buthacus minipectinibus?) globimanus? (Unidentified-1), Compsobuthus spp (arabicus?) (Unidentified-2), Compsobuthus spp (werneri?) (Unidentified-3) and a single specimen of Androctonus spp (australis?) (Unidentified-4), all of which belong to the family Buthidae.