25 March, 2011

Odontobuthus doriae venom as cancer medicine

Scorpions have been used in traditional medicine since ancient times, and in the last decade there have been a lot of research into scorpion venom to find potential agents to be used in medicine and treatment of serious diseases like cancer. Chlorotoxin from the venom of Leiurus quinquestriatus is one example of a very promising agent in the fight against serious brain cancer.

Jamil Zargan and co-workers have now showed that the venom of Odontobuthus doriae (Thorell, 1876) (Buthidae) induced apoptosis (programmed cell death) and inhibits DNA synthesis (inhibit cell growth and cell proliferation) in human neuroblastoma cells (Wikipedia on neuroblastoma). More investigations of the venom of this species are of course necessary, but the properties shown by the venom in this study will make it a valuable therapeutic agent in cancer research.

Abstract:
Scorpion and its organs have been used to cure epilepsy, rheumatism, and male impotency since medieval times. Scorpion venom which contains different compounds like enzyme and non-enzyme proteins, ions, free amino acids, and other organic inorganic substances have been reported to posses antiproliferative, cytotoxic, apoptogenic, and immunosuppressive properties. We for the first time report the apoptotic and antiproliferative effects of scorpion venom (Odontobuthus doriae) in human neuroblastoma cells. After exposure of cells to medium containing varying concentrations of venom (10, 25, 50, 100, and 200 lg/ml), cell viability decreased to 90.75, 75.53, 55.52, 37.85, and 14.30%, respectively, after 24 h. Cells expressed morphological changes like swelling, inhibition of neurite outgrowth, irregular shape, aggregation, rupture of membrane, and release of cytosolic contents after treatment with venom. Lactate dehydrogenase (LDH) level increased in 50 and 100 lg/ml as compared to control, but there was no significant increase in LDH level at a dose of 10 and 20 lg/ml. Two concentrations viz. 50 and 100 lg/ml were selected because of the profound effect of these concentrations on the cellular health and population. Treatment with these two concentrations induced reactive nitrogen intermediates and depolarization in mitochondria. While caspase-3 activity increased in a concentrationdependent manner, only 50 lg/ml was able to fragment DNA. It was interesting to note that at higher dose, i.e., 100 lg/ml, the cells were killed, supposedly by acute necrosis. DNA synthesis evidenced by bromodeoxyuridine (BrdU) incorporation was inhibited in a concentrationdependent manner. The cells without treatment incorporated BrdU with high affinity confirming their cancerous nature whereas very less incorporation was noticed in treated cells. Our results show apoptotic and antiproliferative potential of scorpion venom (O. doriae) in human neuroblastoma cells. These properties make scorpion venom a valuable therapeutic agent in cancer research.

Reference:
Zargan J, Sajad M, Umar S, Naime M, Ali S, Khan HA. Scorpion (Odontobuthus doriae) venom induces apoptosis and inhibits DNA synthesis in human neuroblastoma cells. Mol Cell Biochem. 2011 Feb;348(1-2):173-81. [Subscription required for fulltext]

22 March, 2011

A new Auyantepuia from Surinam

Wilson Lourenco has described a new species in the genus Auyantepuia Gonzalez-Sponga, 1978 (Chactidae) from Surinam last year, but didn't I learn about this paper until today.

Auyantepuia surinamensis Lourenco, 2010

The genus Auyantepuia has been synonymized with other genera by Soleglad & Fet, 2005. Lourenço & Qi (2007) have chosen not to accept this synonymization, and described the new species in Auyantepuia in 2007. The taxonomy of The Scorpion Files follows Soleglad & Fet (2005), but it is impossible for me to know where to put the new species. I have chosen to reinstate Auyantepuia in The Scorpion Files for this species and the one presented here until a new revision on the family Chactidae is published.

Abstract:
A new species, Auyantepuia surinamensis sp. n. (Chactidae), is described from a savannah-like formation, located in NW Albina, between Albina and Moengo in Marowijne, Suriname. The description of the new species confirms the pattern of distribution presented by the genus Auyantepuia, which is basically confined to the Guiano-Amazon regions. The new species represents a first ecological exception, because it was found in a savannah-like formation, whereas all other species have been described from forested formations.

Reference:
Lourenco WR, Duhem B. A new species of Auyantepuia Gonzalez-Sponga, 1978 (Scorpiones, Chactidae) from Suriname. Entomol Mitt Zool Mus Hamburg. 2010 Jun;15(182):137-45.

Family Chactidae

A new Compsobuthus from Algeria

Wilson Lourenco described a new species of Compsobuthus Vachon, 1949 (Buthidae) from Algeria last year, but i didn't learn about this one until today.

Compsobuthus tassili Lourenco, 2010

Abstract:
The Compsobuthus species previously recorded from 'Tassili des Ajjer' in the South of Algeria by Vachon (as Compsobuthus berlandi Vachon, 1950), is now confirmed as a new species. The description is based on one adult male recently collected in the mountains of 'Tassili des Ajjer', and on one of the three specimens previously cited from this region by Vachon as C. berlandi. The new species is presumably endemic to 'Tassili des Ajjer'.

Reference:
Lourenco WR. The Compsobuthus species from 'Tassili des Ajjer', Algeria (Scorpiones, Buthidae) and description of a new species. Entomol Mitt Zool Mus Hamburg. 2010 Jun;15(182):147-55.

Family Buthidae

18 March, 2011

Sting use, risk assessment and control of venom used in Parabuthus transvaalicus

One of the conclusions from my master thesis many years ago was that sting use is probably costly for scorpions and because of this they will only use their stinger if the prey is large and/or the prey resists capture. My study was based on an assumption that use of venom in scorpions was costly and also that scorpions were able to control both the use of the stinger and of the venom. And now it seems that my assumptions were correct :)

Since then, it has been showed that venom use is costly, both in terms of metabolic and ecological costs (Nisani et al, 2007; Nisani, 2008). It has also been demonstrated that some scorpions have two types of venom with different composition (and different "production costs") (Inceoglu et al., 2003).

Now Zia Nisani and Wlliam Hayes have shown that Parabuthus transvaalicus Purcell, 1899 (Buthidae) are able to regulate venom use at three levels:

  • They can choose between a dry and a wet sting (use of venom).
  • When using when om they can control the volum of venom expended, delivering more venom under hight threat and less volum under low threat conditions.
  • They can vary the composition of the venom injected, either using "cheap" prevenom or the more potent protein rich venom.
All of the above results support the hypothesis that scorpions display a venom optimization strategy by regulating venom expenditure based on the level of perceived threat.

This is a great paper that I reccomend to all that are interested in scorpion behavior and scorpion's adaption to their environment!

Abstract:
Venom is a metabolically expensive commodity that animals should use judiciously. The venommetering hypothesis proposes that venomous animals control, or meter, the quantity of venom they deploy during predatory or defensive situations.We sought to clarify experimentally whether the buthid scorpion Parabuthus transvaalicus can regulate defensive venom expenditure based on perceived risk. Scorpions were tested under two threat conditions by inducing them to sting repeatedly a parafilmcovered cup. The high-threat condition involved five sting presentations at 5 s intervals, and the lowthreat condition comprised five sting presentations at 5 min intervals. Venom metering appeared to be modulated at three levels: wet versus dry sting, composition of venom injected and volume of venom delivered. Scorpions delivered dry stings more often under the low-threat condition, but in both conditions were more likely to employ wet stings as the threat persisted. Venom appearance changed during successive stings from clear (potassium-rich ‘prevenom’), to opalescent, to milky (protein-rich ‘venom’), with biochemical analyses (protein assay and MALDI-TOF) confirming the compositional changes. However, progression through this sequence depended on quantity of venom expended, with milky secretion appearing only after the limited quantity of clear secretion was exhausted (i.e. composition and volume covaried). Scorpions injected approximately two-fold more venom per sting during the high-threat compared to the low-threat condition, with milky venom appearing more quickly within the sequence of five stings for the high-threat condition. Thus, these scorpions perceive risk and regulate venom expenditure during stinging according to level of threat, providing further support for the venommetering hypothesis.

Reference:
Nisani Z, Hayes WK. Defensive stinging by Parabuthus transvaalicus scorpions: risk assessment and venom metering. Anim Behav. 2011;81(3):627-33. [Subscription required for fulltext]

Other references mentioned:
Inceoglu B, Lango J, Jing J, Chen L, Doymaz F, Pessah IN, et al. One scorpion, two venoms: Prevenom of Parabuthus transvaalicus acts as an alternative type of venom with distinct mechanism of action. Proc Natl Acad Sci U S A. 2003;100(3):922-7.

Nisani Z, Dunbar SG, Hayes WK. Cost of venom regeneration in Parabuthus transvaalicus (Arachnida: Buthidae). Comp Biochem Physiol A Mol Integr Physiol. 2007 Jun;147(2):509-13.

Nisani Z. Behavioral and physiological ecology of scorpion venom expenditure: stinging, spraying, and venom regeneration: Loma Linda University; 2008 (Ph.D. thesis).

16 March, 2011

Three new anatomy picture collections in SF

Leonard Georg has put together some great anatomy pictures of three species and has shared these pictures with The Scorpion Files:

Hottentotta trilineatus

Isometrus maculatus

Chaerilus celebensis

A big thanks to Leonard for this contribution to The Scorpion Files!

Life cycle of Hadrurus gertschi from Mexico

Ana Quijano-Ravell and co-workers have now published a study on the life cycle of Hadrurus gertschi Soleglad, 1976 (Caraboctonidae)*

[*This species was transfered to Hoffmannihadrurus by Fet & Soleglad i 2008 and this species is listed as Hoffmannihadrurus gertschi (Soleglad, 1976) in The Scorpion Files. Some scientists disagree on the validity of Hoffmannihadurus, as this paper is an example of. Also, some scientists choose to put Hadrurus in Iuridae and reject the validity of Caraboctonidae. See details here.]

Abstract:
The life cycle of Hadrurus gertschi Soleglad 1976 was reconstructed from field data taken during one year of observations in “La Coronilla”, near Ahuehuepan, in Tepecoacuilco de Trujano municipality, Guerrero, Mexico. The species inhabits tropical dry schrub forest in sympatry with three other scorpion species: Centruroides limpidus (Karsch 1879), Vaejovis variegatus Pocock 1898 and Vaejovis atenango Francke and González-Santillán 2007. A growth factor of 1.27 for the carapace length was determined and then used to estimate the morphometric changes between each instar to reach the adult stage and compared them with data obtained in the field. We concluded that this species requires 7 instars and 6 molts, and at least four years to reach adulthood. We also present the phenology of Hadrurus gertschi during one year, measured in relative abundance and surface activity pattern. Matting activity was observed in July, August, September and October.

Reference:
Quijano-Ravell AF, Ponce-Saavedra J, Francke OF. Ciclo de vida de Hadrurus gertschi Soleglad (Scorpiones, Iuridae) en una localidad del Estado de Guerrero, Mexico. Revista Iberica de Arachnologia. 2011;19(133-145).

Thanks to Oscar Francke for sending me this paper!

Family Caraboctonidae

10 March, 2011

A new Diplocentrus from Mexico

Carlos Santibanez-Lopez and co-workers have described a new species of Diplocentrus Peters, 1861 (Scorpionidae*) from Mexico:

Diplocentrus longimanus Santibanez-Lopez, Francke & Athanasiadis, 2011

*Some scorpion scientists have retained the family status of Diplocentridae.

Abstract:
Sixteen scorpion species are recorded from the state of Morelos, including three species of the genus Diplocentrus Peters: one species had been previously reported, a second one represents a new state record for the species, and the third one is described as a new species. Diplocentrus longimanus sp. n., from the Sierra de Huautla in southern Morelos, is described based on adults of both sexes and it is clearly differentiated from its most similar relatives. Maps of the known distribution of the three species are provided.

Reference:
Santibanez-Lopez CE, Francke OF, Athanasiadis MC. The genus Diplocentrus Peters (Scorpiones: Diplocentridae) in Morelos, Mexico. Revista Iberica de Arachnologia. 2011;19:3-13.

Thanks to Carlos Santibanez-Lopez for sending me this paper!

Family Scorpionidae

04 March, 2011

Biology of scorpions from Syria

There are limited data available about the scorpion fauna of Syria. Awan Shehab and co-workers have recently published a paper on the ecology and biology of scorpions in Palmyra, Syria.

The paper takes an extra look at the population structure of Buthacus tadmorensis (Simon, 1892).

Abstract:
Near Palmyra, in the Syrian Desert, 5 species of scorpions belonging to 2 families (Buthidae and Scorpionidae) were observed; Buthacus tadmorensis, Androctonus crassicauda, Leiurus quinquestriatus, Orthochirus scrobiculosus, and Scorpio maurus palmatus. B. tadmorensis accounted for 80.6% of the total number of recovered or observed scorpions, while O. scrobiculosus was the least common (1.4%). Pitfall traps proved to be more effi cient at sampling (304 individuals) than checking under stones (57 individuals). Pitfall trapping results showed that scorpion abundance differed significantly between the 3 survey areas, while their abundance showed no significant diff erence among the 3 areas when employing the under-stone method. Notes on predation of scorpions (interspecific and intraspecific) and predators of scorpions are also included. Seasonal abundance and emergence of scorpions is described briefly. Biometric data on collected scorpion species indicating their weight are given. Population structure of B. tadmorensis during the study period is analyzed.

Reference:
Shehab AH, Amr ZS, Lindsell JA. Ecology and biology of scorpions in Palmyra, Syria. Turkish Journal of Zoology. 2011;35(3):1-9. [Free fulltext]

Thanks to Gerard Dupre for sending me this paper!

01 March, 2011

Scorpion news from China

Zhiyong Di and co-workers have recently published a paper on the scorpion fauna of Yunnan, China. The species occuring here are described and a redescription of the species Euscorpiops kubani Kovarik, 2004 and E. shidian Qi, Zhu & Lourenco, 2005 (Euscorpiidae) is presented.

The paper has a identification key for the scorpions from Yuannan.

Abstract:
We present an identifi cation key to the scorpion species of Yunnan (China) with notes on the distribution and ecology. Euscorpiops kubani is recorded for the first time for China. The redescriptions of Euscorpiops shidian and E. kubani are provided. The number of known scorpion species from Yunnan is raised to nine.

Reference:
Di Z, Yawen H, Wu Y, Cao Z, Liu H, Jiang D, et al. The scorpions of Yunnan (China): updated identification key, new record and redescriptions of Euscorpiops kubani and E. shidian (Arachnida, Scorpiones). ZooKeys. 2011;82:1-33. [free fulltext]

Thanks to Gerard Dupre for sending me this paper!