De novo transcriptomic analysis of the venomous glands from the scorpion Heterometrus spinifer revealed unique and extremely high diversity of the venom peptides

Expression and Functional Characterization of Oryzacystatin II Protein from Oryza sativa L. Indica Rice and Its Potential Role as a Bioinsecticide Against Major Insects of Rice

Rice (Oryza sativaL.) is a crucial staple food crop globally, facing significant challenges from various pests that affect crop productivity and quality. Conventional pesticide usage has limitations, necessitating the development of sustainable pest management strategies. This study focuses on the expression, purification, and functional characterization of Oryzacystatin II (OC-II), a protein derived from O. sativaL. Indica rice, with the intent to evaluate its potential as a bioinsecticide against rice pests. The OC-II gene was expressed and purified, and purification confirmed its molecular weight (∼12 kDa) and protein sequence through LC-MS/MS analysis and Western blotting. The IC50 value of OC-II was calculated as 0.06 μM, and the inhibition was identified as a competitive inhibition. The protein exhibited efficient control of both pests at the nymph and adult stages, with lower probing marks observed on treated plants. The inhibition of cathepsin B enzyme activity in insects further confirmed the bioactivity of the OC-II protein. Molecular docking and molecular dynamics simulations provided insights into the interaction between the OC-II protein and cathepsin enzymes reported in BPH and WBPH. Further investigations can focus on optimizing production methods and exploring the specificity and efficacy of the OC-II protein against other crop pests to enhance its practical applications.

Comparative Proteomic Analysis of the Venoms from the Most Dangerous Scorpions in Morocco: Androctonus mauritanicus and Buthus occitanus

Morocco is known to harbor two of the world's most dangerous scorpion species: the black Androctonus mauritanicus (Am) and the yellow Buthus occitanus (Bo), responsible for 83% and 14% of severe envenomation cases, respectively. Scorpion venom is a mixture of biological molecules of variable structures and activities, most of which are proteins of low molecular weights referred to as toxins. In addition to toxins, scorpion venoms also contain biogenic amines, polyamines, and enzymes. With the aim of investigating the composition of the Am and Bo venoms, we conducted an analysis of the venoms by mass spectrometry (ESI-MS) after separation by reversed-phase HPLC chromatography. Results from a total of 19 fractions obtained for the Am venom versus 22 fractions for the Bo venom allowed the identification of approximately 410 and 252 molecular masses, respectively. In both venoms, the most abundant toxins were found to range between 2-5 kDa and 6-8 kDa. This proteomic analysis not only allowed the drawing of an extensive mass fingerprint of the Androctonus mauritanicus and Buthus occitanus venoms but also provided a better insight into the nature of their toxins.

Bioactive peptides from scorpion venoms: therapeutic scaffolds and pharmacological tools

Evolution and natural selection have endowed animal venoms, including scorpion venoms, with a wide range of pharmacological properties. Consequently, scorpions, their venoms, and/or their body parts have been used since time immemorial in traditional medicines, especially in Africa and Asia. With respect to their pharmacological potential, bioactive peptides from scorpion venoms have become an important source of scientific research. With the rapid increase in the characterization of various components from scorpion venoms, a large number of peptides are identified with an aim of combating a myriad of emerging global health problems. Moreover, some scorpion venom-derived peptides have been established as potential scaffolds helpful for drug development. In this review, we summarize the promising scorpion venoms-derived peptides as drug candidates. Accordingly, we highlight the data and knowledge needed for continuous characterization and development of additional natural peptides from scorpion venoms, as potential drugs that can treat related diseases.

Transcriptomic and proteomic analyses of venom glands from scorpions Liocheles australasiae, Mesobuthus martensii, and Scorpio maurus palmatus

Scorpion venom contains a cocktail of differing peptides and proteins. Previous studies focused on the identification of species-specific components in scorpion venoms, and whether there could be peptides and/or proteins conserved in the venom gland of a scorpion ancestor has been rarely investigated. Here, using a combination of transcriptomic and proteomic approaches, putative conserved toxins from the venom glands of scorpions Liocheles australasiae, Mesobuthus martensii, and Scorpio maurus palmatus were identified and compared. Similar to other studies, more than half of the conserved toxins are predominantly proteins including proteases. On the other hand, unique venom peptides, including ion channel toxins were revealed specifically in the M. martensii. The sodium channel toxin peptides revealed in M. martensii consolidated that scorpions in the Buthidae are able to envenomate their prey wih highly neurotoxic venom. This study suggested that these conserved proteins had already formed part of the arsenal in the venom gland of the common ancestor of scorpions, and likely perform important functional roles in envenomation during scorpion evolution.

A non-lethal method for studying scorpion venom gland transcriptomes, with a review of potentially suitable taxa to which it can be applied

Scorpion venoms are mixtures of proteins, peptides and small molecular compounds with high specificity for ion channels and are therefore considered to be promising candidates in the venoms-to-drugs pipeline. Transcriptomes are important tools for studying the composition and expression of scorpion venom. Unfortunately, studying the venom gland transcriptome traditionally requires sacrificing the animal and therefore is always a single snapshot in time. This paper describes a new way of generating a scorpion venom gland transcriptome without sacrificing the animal, thereby allowing the study of the transcriptome at various time points within a single individual. By comparing these venom-derived transcriptomes to the traditional whole-telson transcriptomes we show that the relative expression levels of the major toxin classes are similar. We further performed a multi-day extraction using our proposed method to show the possibility of doing a multiple time point transcriptome analysis. This allows for the study of patterns of toxin gene activation over time a single individual, and allows assessment of the effects of diet, season and other factors that are known or likely to influence intraindividual venom composition. We discuss the gland characteristics that may allow this method to be successful in scorpions and provide a review of other venomous taxa to which this method may potentially be successfully applied.

De novo transcriptomic and proteomic analysis and potential toxin screening of Mesobuthus martensii samples from four different provinces

ETHNOPHARMACOLOGICAL RELEVANCE

As well-known medicinal materials in traditional Chinese medicine, scorpions, commonly called as Quanxie () in Chinese, have been widely used to treat several diseases such as rheumatoid arthritis, apoplexy, epilepsy and chronic pain for more than a thousand years. Not only in the ancient times, the scorpions have also been recorded nowadays in the Pharmacopoeia of the People's Republic of China since 1963.

AIM OF STUDY

This study aims to explore the differences in composition of the venom of scorpions from different regions by using the method of transcriptomics and proteomics.

MATERIALS AND METHODS

Whole de novo transcriptomes, proteomics and their bioinformatic analyses were performed on samples of the scorpion Mesobuthus martensii and their venoms from four different provinces with clear geographical boundaries, including Hebei, Henan, Shandong and Shanxi.

RESULTS

The four captured samples had the same morphology, and the conserved CO-1 sequence matched that of M. martensii. A total of 141,003 of 174,653 transcripts were identified as unigenes, of which we successfully annotated 51,627 (36.61%), 21,970 (15.58%), 7,168 (5.08%), and 45,263 (32.10%) unigenes with the NR, GO, KEGG and SWISSPROT databases, respectively, while a total of 427 proteins were collected from the protein extracted from venoms. Both GO and KEGG annotations exhibited only slight differences among the four samples while the expression level of gene and protein was quite different. A total of 249 toxin-related unigenes were successfully screened, including 41 serine proteases and serine protease inhibitors, 39 potassium channel toxins, 38 phospholipases, 16 host defense peptides, 9 metalloproteases, and 50 other toxins. Although the toxin species were similar among the four samples, the gene expression of each toxin varied considerably, for example, the scorpion from HB province has the most abundant expression quality in sequences c48391_g1, c55239_g1 and c47749_g1 while the lowest expressions of c51178_g1, c62033_g3 and c63754_g2.

CONCLUSION

The regional differences in the transcriptomes and proteomes of M. martensii are mainly from expression levels e.g. toxins rather than expression species, of which the method can be further extended to evaluate the qualities of traditional Chinese medicines obtained from different regions.

Identification of an antiviral component from the venom of the scorpion Liocheles australasiae using transcriptomic and mass spectrometric analyses

Scorpion venom contains a variety of biologically active peptides. Among them, neurotoxins are major components in the venom, but it also contains peptides that show antimicrobial activity. Previously, we identified three insecticidal peptides from the venom of the Liocheles australasiae scorpion, but activities and structures of other venom components remained unknown. In this study, we performed a transcriptome analysis of the venom gland of the scorpion L. australasiae to gain a comprehensive understanding of its venom components. The result shows that potassium channel toxin-like peptides were the most diverse, whereas only a limited number of sodium channel toxin-like peptides were observed. In addition to these neurotoxin-like peptides, many non-disulfide-bridged peptides were identified, suggesting that these components have some critical roles in the L. australasiae venom. In this study, we also isolated a component with antiviral activity against hepatitis C virus using a bioassay-guided fractionation approach. By integrating mass spectrometric and transcriptomic data, we successfully identified LaPLA₂-1 as an anti-HCV component. LaPLA₂-1 is a phospholipase A₂ having a heterodimeric structure that is N-glycosylated at the N-terminal region. Since the antiviral activity of LaPLA₂-1 was inhibited by a PLA₂ inhibitor, the enzymatic activity of LaPLA₂-1 is likely to be involved in its antiviral activity.

Cloning and identification of a new multifunctional Ascaris-type peptide from the hemolymph of Buthus martensii Karsch

Only a few work have been done for peptides from non-venom gland tissues of venomous animals. Here, with the help of the whole body transcriptomic and the hemolymph proteomic data of the Chinese scorpion Buthus martensii Karsch, we identified the first Ascaris-type peptide BmHDP from scorpion hemolymph. The precursor of BmHDP has 80 residues, including a 16 residue signal peptide and a 64 residue mature peptide. The mature peptide has 10 conserved cysteines and adopts a conserved Ascaris-type fold. Using combined inclusion body refolding and biochemical identification strategies, recombinant BmHDP was obtained successfully. Protease inhibitory assays showed that BmHDP inhibited chymotrypsin apparently at a concentration of 8 nM. Patch-clamp experiments showed that BmHDP inhibited the Kv1.3 potassium channel apparently at a concentration of 1000 nM. Coagulation experiment assays showed that BmHDP inhibited intrinsic coagulation pathway apparently at a concentration of 500 nM. To the best of our knowledge, BmHDP is the first Ascaris-type peptide from scorpion hemolymph. Our work highlighted a functional link between scorpion non-venom gland peptides and venom gland toxin peptides, and suggested that scorpion hemolymph might be a new source of bioactive peptides.

Transcriptomic and proteomic analyses of the venom and venom glands of Centruroides hirsutipalpus, a dangerous scorpion from Mexico

Centruroides hirsutipalpus (Scorpiones: Buthidae) is related to the "striped scorpion" group inhabiting the western Pacific region of Mexico. Human accidents caused by this species are medically important due to the great number of people stung and the severity of the resulting intoxication. This communication reports an extensive venom characterization using high-throughput proteomic and Illumina transcriptomic sequencing performed with RNA purified from its venom glands. 2,553,529 reads were assembled into 44,579 transcripts. From these transcripts, 23,880 were successfully annoted using Trinotate. Using specialized databases and by performing bioinformatic searches, it was possible to identify 147 putative venom protein transcripts. These include α- and β-type sodium channel toxins (NaScTx), potassium channel toxins (KScTx) (α-, β-, δ-, γ- and λ-types), enzymes (metalloproteases, hyaluronidases, phospholipases, serine proteases, and monooxygenases), protease inhibitors, host defense peptides (HDPs) such as defensins, non-disulfide bridge peptides (NDBPs), anionic peptides, superfamily CAP proteins, insulin growth factor-binding proteins (IGFBPs), orphan peptides, and other venom components (La1 peptides). De novo tandem mass spectrometric sequencing of digested venom identificatied 50 peptides. The venom of C. hirsutipalpus contains the highest reported number (77) of transcripts encoding NaScTxs, which are the components responsible for human fatalities.

Transcriptome annotation and characterization of novel toxins in six scorpion species

Background

Venom has evolved in parallel in multiple animals for the purpose of self-defense, prey capture or both. These venoms typically consist of highly complex mixtures of toxins: diverse bioactive peptides and/or proteins each with a specific pharmacological activity. Because of their specificity, they can be used as experimental tools to study cell mechanisms and develop novel medicines and drugs. It is therefore potentially valuable to explore the venoms of various animals to characterize their toxins and identify novel toxin-families. This study focuses on the annotation and exploration of the transcriptomes of six scorpion species from three different families. The transcriptomes were annotated with a custom-built automated pipeline, primarily consisting of Basic Local Alignment Search Tool searches against UniProt databases and filter steps based on transcript coverage.

Results

We annotated the transcriptomes of four scorpions from the family Buthidae, one from Iuridae and one from Diplocentridae using our annotation pipeline. We found that the four buthid scorpions primarily produce disulfide-bridged ion-channel targeting toxins, while the non-buthid scorpions have a higher abundance of non-disulfide-bridged toxins. Furthermore, analysis of the “unidentified” transcripts resulted in the discovery of six novel putative toxin families containing a total of 37 novel putative toxins. Additionally, 33 novel toxins in existing toxin-families were found. Lastly, 19 novel putative secreted proteins without toxin-like disulfide bonds were found.

Conclusions

We were able to assign most transcripts to a toxin family and classify the venom composition for all six scorpions. In addition to advancing our fundamental knowledge of scorpion venomics, this study may serve as a starting point for future research by facilitating the identification of the venom composition of scorpions and identifying novel putative toxin families.

Electronic supplementary material

The online version of this article (10.1186/s12864-019-6013-6) contains supplementary material, which is available to authorized users.

Transcriptomic and Proteomic Analyses Reveal the Diversity of Venom Components from the Vaejovid Scorpion Serradigitus gertschi

To understand the diversity of scorpion venom, RNA from venomous glands from a sawfinger scorpion, Serradigitus gertschi, of the family Vaejovidae, was extracted and used for transcriptomic analysis. A total of 84,835 transcripts were assembled after Illumina sequencing. From those, 119 transcripts were annotated and found to putatively code for peptides or proteins that share sequence similarities with the previously reported venom components of other species. In accordance with sequence similarity, the transcripts were classified as potentially coding for 37 ion channel toxins; 17 host defense peptides; 28 enzymes, including phospholipases, hyaluronidases, metalloproteases, and serine proteases; nine protease inhibitor-like peptides; 10 peptides of the cysteine-rich secretory proteins, antigen 5, and pathogenesis-related 1 protein superfamily; seven La1-like peptides; and 11 sequences classified as "other venom components". A mass fingerprint performed by mass spectrometry identified 204 components with molecular masses varying from 444.26 Da to 12,432.80 Da, plus several higher molecular weight proteins whose precise masses were not determined. The LC-MS/MS analysis of a tryptic digestion of the soluble venom resulted in the de novo determination of 16,840 peptide sequences, 24 of which matched sequences predicted from the translated transcriptome. The database presented here increases our general knowledge of the biodiversity of venom components from neglected non-buthid scorpions.