Transcriptomic Analysis Reveals Diverse Expression of Scorpion Toxin Genes in Mesobuthus martensii.

Scorpions, an ancient group of venomous invertebrates, have existed for over 430 million years. Their toxins, important for predation and defense, exhibit a variety of biological and pharmacological activities. Research on scorpion toxins has spanned decades. Notably, the toxin genes of Mesobuthus martensii (Scorpiones: Buthidae), a well-known Chinese herbal medicine, have been described at genomic and proteomic levels. However, previous studies primarily focused on the toxin genes expressed in the venom glands, overlooking their expression in multiple tissues. This study analyzed transcriptomes from 14 tissues of M. martensii. Gene annotation revealed 83 toxin and toxin-like genes, including those affecting sodium, potassium, calcium, and chloride ion channels. Approximately 70% of toxin genes were highly expressed in the vesicle; additionally, some exhibited low or no expression in the vesicle while showing high expression in other tissues. Beyond the vesicle, high expression levels of toxin genes were observed in metasoma segments II-V, blood, lateral eyes, chelicerae, legs, pedipalp chelae, femurs, and patellae. This expression pattern suggests that toxin genes are recruited from multiple tissues and may help prevent intraspecific harm during courtship and competition for prey. These findings inspire further research into the evolutionary recruitment process of scorpion toxins.

Scorpiops zhui sp. n., a new species of Scorpiops Peters, 1861 from Chongqing, China (Scorpiones: Scorpiopidae).

A new species of Scorpiops Peters, 1861 is described from Wuxi and Wushan County, Chongqing City, China. The new species is mainly characterized by a moderate size, in relation to the other species of genus, with dark reddish-brown to reddish-black coloration; 15-17 (usually 17) external trichobothria (5 eb, 1-2 esb, 1-2 em, 4 est, 4 et), 8-11 (usually 10) ventral trichobothria in the pedipalp patella and 4-5 (usually 5) ventral trichobothria on chela; pedipalp chela fingers are scalloped in males and nearly straight in females. With the present description the number of known species of Scorpiops recorded from China is raised to 33.

Transcriptome Sequencing and Comparison of Venom Glands Revealed Intraspecific Differentiation and Expression Characteristics of Toxin and Defensin Genes in Mesobuthus martensii Populations.

Mesobuthus martensii, a famous and important Traditional Chinese Medicine has a long medical history and unique functions. It is the first scorpion species whose whole genome was sequenced worldwide. In addition, it is the most widespread and infamous poisonous animal in northern China with complex habitats. It possesses several kinds of toxins that can regulate different ion channels and serve as crucial natural drug resources. Extensive and in-depth studies have been performed on the structures and functions of toxins of M. martensii. In this research, we compared the morphology of M. martensii populations from different localities and calculated the COI genetic distance to determine intraspecific variations. Transcriptome sequencing by RNA-sequencing of the venom glands of M. martensii from ten localities and M. eupeus from one locality was analyzed. The results revealed intraspecific variation in the expression of sodium channel toxin genes, potassium channel toxin genes, calcium channel toxin genes, chloride channel toxin genes, and defensin genes that could be related to the habitats in which these populations are distributed, except the genetic relationships. However, it is not the same in different toxin families. M. martensii and M. eupeus exhibit sexual dimorphism under the expression of toxin genes, which also vary in different toxin families. The following order was recorded in the difference of expression of sodium channel toxin genes: interspecific difference; differences among different populations of the same species; differences between sexes in the same population, whereas the order in the difference of expression of potassium channel toxin genes was interspecific difference; differences between both sexes of same populations; differences among the same sex in different populations of the same species. In addition, there existed fewer expressed genes of calcium channel toxins, chloride channel toxins, and defensins (no more than four members in each family), and their expression differences were not distinct. Interestingly, the expression of two calcium channel toxin genes showed a preference for males and certain populations. We found a difference in the expression of sodium channel toxin genes, potassium channel toxin genes, and chloride channel toxin genes between M. martensii and M. eupeus. In most cases, the expression of one member of the toxin gene clusters distributed in series on the genome were close in different populations and genders, and the members of most clusters expressed in same population and gender tended to be the different. Twenty-one toxin genes were found with the MS/MS identification evidence of M. martensii venom. Since scorpions were not subjected to electrical stimulation or other special treatments before conducting the transcriptome extraction experiment, the results suggested the presence of intraspecific variation and sexual dimorphism of toxin components which revealed the expression characteristics of toxin and defensin genes in M. martensii. We believe this study will promote further in-depth research and use of scorpions and their toxin resources, which in turn will be helpful in standardizing the identification and medical applications of Quanxie in traditional Chinese medicine.

The revalidation of Otostigmus (O.) lewisi Song et al., 2005 (Scolopendromorpha, Scolopendridae) based on new material from Jiacha County, China.

Otostigmus (O.) lewisiSong et al., 2005 was described from sub-adult specimens from Jiacha County (Xizang, China), but was synonymized by Lewis (2010) with the Nepalese species O. (O.) beroni Lewis, 2001. The latter was also recorded from Jilong County (Xizang, China) by Song et al. (2005). Following a comparison of O. (O.) beroni from Jilong County with new materials of O. (O.) lewisi from Jiacha County, we reaffirm that O. (O.) lewisi is a valid species.

Scorpiopslourencoi sp. nov., the revalidation of Scorpiopsatomatus Qi, Zhu & Lourenço, 2005, and the redescription of Scorpiopstibetanus Hirst, 1911 (Scorpiones, Scorpiopidae) from China.

Scorpiopslourencoi sp. nov. is described from Shigatse, Xizang. Scorpiopsatomatus Qi, Zhu & Lourenço, 2005 and Scorpiopspococki Qi, Zhu & Lourenço, 2005 were synonymized by Kovarík et al. (2020) as two junior synonyms of Scorpiopstibetanus Hirst, 1911 but based on several field surveys in Xizang in recent years, and a careful survey of the literature, S.atomatus is reaffirmed as a valid species and S.tibetanus is redescribed, both based on newly collected specimens. This brings the total number of species of Scorpiops recorded in China to 32.

Scolopocryptops longipes sp. nov., a troglobitic scolopocryptopine centipede (Chilopoda: Scolopendromorpha: Scolopocryptopidae) from China.

We describe Scolopocryptops longipes sp. nov., a new troglobitic scolopocryptopine centipede species from a karstic area in southern China. The species was found in Shuiba Cave of Libo County, Guizhou Province. The cephalic plate wider than long, with complete margination along the lateral margin of cephalic plate; TT619 with complete paramedian sutures; tibia, tarsus 1 and tarsus 2 of leg 22 each with one spur; prefemur and femur of ultimate legs glabrous, tibia and tarsi with dense bristles. S. longipes is the second troglobitic scolopocryptopine in China and the fourth in the world described thus far.

Otostigmus (Otostigmus) xizangensis n. sp., from China and a case of sexual dimorphism in the subgenus Otostigmus (Otostigmus) Porat, 1876 (Chilopoda, Scolopendromorpha, Scolopendridae).

Otostigmus (Otostigmus) xizangensis n. sp., a new species of subgenus Otostigmus Porat, 1876 from Xizang, China, is described and illustrated. The new species is diagnosed as follows: antennae 1719 articles (mainly 19), basal antennal articles cylindrical; forcipular tooth-plate with 4 teeth; tergites (5) 620 with complete paramedian sutures; well-developed lateral margination on tergites (6) 921; ultimate leg prefemora with four rows of spines, leg 20 with one tarsal spur. The coxopleural process of O. (O.) xizangensis n. sp. exhibits remarkable sexual dimorphism, being long and curved in females, short and straight in males.

Euscorpiops lii sp. nov. and a key of the genus Euscorpiops Vachon, 1980 (Scorpiones, Scorpiopidae) from China.

A new species, Euscorpiops lii sp. nov., from Xizang (Tibet) in southwest China is described herein. Adult scorpions in this species are principally characterized by yellow-brown colour, a length of less than 40 mm, 17 trichobothria on the external surface of the pedipalp patella and usually six trichobothria on the ventral surface of the pedipalp patella in both sexes. With the description of this new species, the number of known species of the genus Euscorpiops from China is raised to 13 (five species found in Xizang, including the new species, and eight other species in Yunnan). A key to the species of the genus Euscorpiops from China is presented.

Immunosuppressive effects of a novel potassium channel toxin Ktx-Sp2 from Scorpiops Pocoki.

BACKGROUND: The cDNA Library of venomous animals could provide abundant bioactive peptides coding information and is an important resource for screening bioactive peptides that target and regulate disease-related ion channels. To further explore the potential medicinal usage of the transcriptome database of Scorpiops Pocoki's venom gland, this research identified the function of a new potassium channel toxin Ktx-Sp2, whose gene was screened from the database by sequence alignment. RESULTS: The mature peptide of Ktx-Sp2 was obtained by genetic engineering. Whole-cell patch-clamp experiment showed that Ktx-Sp2 peptide could effectively block three types of exogenous voltage-gated potassium channels-Kv1.1, Kv1.2 and Kv1.3, among which, the blocking activity for Kv1.3 was relatively high, showing selectivity to some extent. Taking Jurkat T cells as the cell model, this study found that Ktx-Sp2 peptide could also effectively block endogenous Kv1.3, significantly reduce the free calcium concentration in Jurkat T cells, inhibit the activation of Jurkat T cells and reduce the release of inflammatory cytokines IL-2, showing a strong immunosuppressant effect. CONCLUSIONS: This study further proves that the transcriptome database of the Scorpiops Pocoki venom gland is an important resource for discovery of novel bioactive polypeptide coding genes. The newly screened Kv1.3 channel blocker Ktx-Sp2 expanded the range of leading compounds for the treatment of autoimmune diseases and promoted the development and application of scorpion toxin peptides in the field of biomedicine.

Homeosis in a scorpion supports a telopodal origin of pectines and components of the book lungs.

BACKGROUND: The morphological and functional evolution of appendages has played a key role in the diversification of arthropods. While the ancestral arthropod appendage is held to be polyramous, terrestriality is associated with the reduction or loss of appendage rami, which may obscure the homology of different appendage derivatives. Proxies for appendage homology have included surveys of cross-reactive antibodies for wing markers like Nubbin/PDM, which have suggested that the abdominal appendages of arachnids (e.g., book lungs, tracheal tubules) are derived from ancestral gills (epipods). RESULTS: Here, we discovered a rare case of inferred homeosis in a scorpion in which the bilobed genital opercula and the pectines are transformed to walking legs, and an abnormal sternite shows a book lung close to an everted structure comparable to the morphology of some Palaeozoic scorpion fossils. CONCLUSIONS: The observed morphology is consistent with abnormal expression of homeotic genes during embryonic development. The phenotype of this abnormal specimen suggests that the genital opercula, the pectines, and parts of the book lung may be derived from the telopodite of abdominal appendages rather than from epipods. This interpretation contradicts the "ancestral gill" hypothesis but reconciles features of the Palaeozoic scorpion fossil record with the embryology of modern scorpions.

Cloning, expression and identification of KTX-Sp4, a selective Kv1.3 peptidic blocker from Scorpiops pococki.

BACKGROUND: Specific and selective peptidic blockers of Kv1.3 channels can serve as a valuable drug lead for treating T cell-mediated autoimmune diseases, and scorpion venom is an important source of kv1.3 channel inhibitors. Through conducting transcriptomic sequencing for the venom gland of Scorpiops pococki from Xizang province of China, this research aims to discover a novel functional gene encoding peptidic blocker of Kv1.3, and identify its function. RESULTS: We screened out a new peptide toxin KTX-Sp4 which had 43 amino acids including six cysteine residues. Electrophysiological experiments indicated that recombinant expression products of KTX-Sp4 blocked both endogenous and exogenous Kv1.3 channel concentration-dependently, and exhibited good selectivity on Kv1.3 over Kv1.1, Kv1.2, respectively. Mutation experiments showed that the Kv1 turret region was responsible for the selectivity of KTX-Sp4 peptide on Kv1.3 over Kv1.1. CONCLUSIONS: This work not only provided a novel lead compound for the development of anti autoimmune disease drugs, but also enriched the molecular basis for the interaction between scorpion toxins and potassium channels, serving as an important theoretical basis for designing high selective Kv1.3 peptide inhibitors.

Molecular characterization and expression analysis of CSαß defensin genes from the scorpion Mesobuthus martensii.

Defensins are important components of innate host defence system against bacteria, fungi, parasites and viruses. Here, we predicted six potential defensin genes from the genome of the scorpion Mesobuthus martensii and then validated four genes from them via the combination of PCR and genomic sequence analysis. These four scorpion defensin genes share the same gene organization and structure of two exons and one phase-I intron with the GT-AG rule. Conserved motif and phylogenetic analysis showed that they belonged to the members of the invertebrate cysteine-stabilized α-helix/ß-sheet motif defensin (CSαß) defensin family. All these four CSαß defensin genes have the expression feature of constitutive transcription (CON) by the whole scorpion infection model, promoter sequence analysis and dual luciferase assays. Further evolution and comparison analysis found that the invertebrate CSαß defensin genes from most of arachnids and mollusks appear to share the expression pattern of CON, but those from insects and lower invertebrates (nematodes, annelids, cnidarians and sponges) seem to have identical inducible transcription (IND) after being challenged by microorganisms. Together, we identified four scorpion CSαß defensin genes with the expression feature of CON, and characterized the diversified expression patterns of the invertebrate CSαß defensin genes, which will shed insights into the evolution of the invertebrate CSαß defensin genes and their expression patterns.

Chaeriluspseudoconchiformus sp. n. and an updated key of the chaerilid scorpions from China (Scorpiones, Chaerilidae).

A new species, Chaeriluspseudoconchiformus sp. n., is described from Xizang, China. The present new species is distinguished from its congeners by a body length of 32-40 mm, carapace with the anterior margin straight, chela with length/width ratio average of 3.3 in males (3.2-3.4, two adults), and 2.5 in females (2.3-2.6, nine adults), eight or nine (eight usually) rows of denticles on fixed and movable fingers of pedipalp chelae, five pectinal teeth in males and three or four in females. To date, the chaerilid species fauna of China consists of nine species. An updated identification key to Chaerilus from China is presented.

Scorpiopsingens sp. n. and an updated key to the Scorpiops from China (Scorpiones, Euscorpiidae, Scorpiopinae).

A new species, Scorpiopsingens sp. n., from Xizang, is described and illustrated. Scorpiopsingens sp. n. is characterized by yellow-brown color, large size (length of adults above 70.0 mm), small and dense granules on tegument, a pair of small median eyes, 17 external trichobothria (5 eb, 2 esb, 2 em, 4 est, 4 et), and 7 or 8 (usually 7) ventral trichobothria in the pedipalp patella, chela with a length/width ratio average of 2.2 in males and females, pedipalp chela fingers on adult females and males scalloped, pectinal teeth count 6-8, pectinal fulcra absent. With the description of this new species, the number of known species of Scorpiops from China is raised to 12. An updated identification key to Scorpiops from China is presented.

Genome-wide analysis of homeobox genes from Mesobuthus martensii reveals Hox gene duplication in scorpions.

Homeobox genes belong to a large gene group, which encodes the famous DNA-binding homeodomain that plays a key role in development and cellular differentiation during embryogenesis in animals. Here, one hundred forty-nine homeobox genes were identified from the Asian scorpion, Mesobuthus martensii (Chelicerata: Arachnida: Scorpiones: Buthidae) based on our newly assembled genome sequence with approximately 248 × coverage. The identified homeobox genes were categorized into eight classes including 82 families: 67 ANTP class genes, 33 PRD genes, 11 LIM genes, five POU genes, six SINE genes, 14 TALE genes, five CUT genes, two ZF genes and six unclassified genes. Transcriptome data confirmed that more than half of the genes were expressed in adults. The homeobox gene diversity of the eight classes is similar to the previously analyzed Mandibulata arthropods. Interestingly, it is hypothesized that the scorpion M. martensii may have two Hox clusters. The first complete genome-wide analysis of homeobox genes in Chelicerata not only reveals the repertoire of scorpion, arachnid and chelicerate homeobox genes, but also shows some insights into the evolution of arthropod homeobox genes.

miR-339-5p inhibits alcohol-induced brain inflammation through regulating NF-κB pathway.

Alcohol-induced neuroinflammation is mediated by the innate immunesystem. Pro-inflammatory responses to alcohol are modulated by miRNAs. The miRNA miR-339-5p has previously been found to be upregulated in alcohol-induced neuroinflammation. However, little has been elucidated on the regulatory functions of this miRNA in alcohol-induced neuroinflammation. We investigated the function of miR-339-5p in alcohol exposed brain tissue and isolated microglial cells using ex vivo and in vitro techniques. Our results show that alcohol induces transcription of miR 339-5p, IL-6, IL-1ß and TNF-α in mouse brain tissue and isolated microglial cells by activating NF-κB. Alcohol activation of NF-κB allows for nuclear translocation of the NF-κB subunit p65 and expression of pro-inflammatory mediators. miR-339-5p inhibited expression of these pro-inflammatory factors through the NF-κB pathway by abolishing IKK-ß and IKK-ε activity.

Proteomic analysis of the venom from the scorpion Mesobuthus martensii.

The scorpion Mesobuthus martensii is the most populous species in eastern Asian countries, and several toxic components have been identified from their venoms. Nevertheless, a complete proteomic profile of the venom of M. martensii is still not available. In this study, the venom of M. martensii was analyzed by comprehensive proteomic approaches. 153 fractions were isolated from the M. martensii venom by 2-DE, SDS-PAGE and RP-HPLC. The ESI-Q-TOF MS results of all fractions were used to search the scorpion genomic and transcriptomic databases. Totally, 227 non-redundant protein sequences were unambiguously identified, composed of 134 previously known and 93 previously unknown proteins. Among 134 previously known proteins, 115 proteins were firstly confirmed from the M. martensii crude venom and 19 toxins were confirmed once again, involving 43 typical toxins, 7 atypical toxins, 12 venom enzymes and 72 cell associated proteins. In typical toxins, 7 novel-toxin sequences were identified, including 3 Na(+)-channel toxins, 3K(+)-channel toxins and 1 no-annotation toxin. These results increased 230% (115/50) venom components compared with previous studies from the M. martensii venom, especially 50% (24/48) typical toxins. Additionally, a mass fingerprint obtained by MALDI-TOF MS indicated that the scorpion venom contained more than 200 different molecular mass components. BIOLOGICAL SIGNIFICANCE: This work firstly gave a systematic investigation of the M. martensii venom by combined proteomics strategy coupled with genomics and transcriptomics. A large number of protein components were unambiguously identified from the venom of M. martensii, most of which were confirmed for the first time. We also contributed 7 novel-toxin sequences and 93 protein sequences previously unknown to be part of the venom, for which we assigned potential biological functions. Besides, we obtained a mass fingerprint of the M. martensii venom. Together, our study not only provides the most comprehensive catalog of the molecular diversity of the M. martensii venom at the proteomic level, but also enriches the composition information of scorpion venom.

Overview of scorpion species from China and their toxins.

Scorpions are one of the most ancient groups of terrestrial animals. They have maintained a steady morphology over more than 400 million years of evolution. Their venom arsenals for capturing prey and defending against predators may play a critical role in their ancient and conservative appearance. In the current review, we present the scorpion fauna of China: 53 species covering five families and 12 genera. We also systematically list toxins or genes from Chinese scorpion species, involving eight species covering four families. Furthermore, we review the diverse functions of typical toxins from Chinese scorpion species, involving Na+ channel modulators, K+ channel blockers, antimicrobial peptides and protease inhibitors. Using scorpion species and their toxins from China as an example, we build the bridge between scorpion species and their toxins, which helps us to understand the molecular and functional diversity of scorpion venom arsenal, the dynamic and functional evolution of scorpion toxins, and the potential relationships of scorpion species and their toxins.

History of study, updated checklist, distribution and key of scorpions (Arachnida: Scorpiones) from China.

This review describes the history of taxonomic research on scorpions and provides an updated checklist and key of the scorpions currently known in China. This checklist is based on a thorough review of the extant literatures on scorpion species whose presence has been confirmed in China through field expeditions and examination of scorpion collections, excepting a few members that have no clear distribution or are currently in doubt. Totally, the scorpion fauna of China consists of 53 species and subspecies belonging to 12 genera crossing five families, with 33 species (62.3%) and one genus being recorded as endemic. Additionally, identification key and the distribution of scorpions from China are provided.

The genome of Mesobuthus martensii reveals a unique adaptation model of arthropods.

Representing a basal branch of arachnids, scorpions are known as 'living fossils' that maintain an ancient anatomy and are adapted to have survived extreme climate changes. Here we report the genome sequence of Mesobuthus martensii, containing 32,016 protein-coding genes, the most among sequenced arthropods. Although M. martensii appears to evolve conservatively, it has a greater gene family turnover than the insects that have undergone diverse morphological and physiological changes, suggesting the decoupling of the molecular and morphological evolution in scorpions. Underlying the long-term adaptation of scorpions is the expansion of the gene families enriched in basic metabolic pathways, signalling pathways, neurotoxins and cytochrome P450, and the different dynamics of expansion between the shared and the scorpion lineage-specific gene families. Genomic and transcriptomic analyses further illustrate the important genetic features associated with prey, nocturnal behaviour, feeding and detoxification. The M. martensii genome reveals a unique adaptation model of arthropods, offering new insights into the genetic bases of the living fossils.