Background: TheAndroctonus crassicauda, belonging to the genusAndroctonusof the family Buthidae, is the most venomous scorpion in Middle East countries. However, the venom gland transcriptome profile ofA. crassicaudascorpion has not yet been studied. In this study, we elucidated and compared the venom gland gene expression profiles of adult and juvenile male scorpionA. crassicaudausing high-throughput transcriptome sequencing. This is the first report of transcriptional analysis of the venom glands of scorpions in different growth stages, with insights into the identification of the key genes during venom gland development.Results: A total of 209,951 mRNA transcripts were identified from total RNA-seq data, of which 963 transcripts were differentially expressed (DE) in adult and juvenile scorpions (p < 0.01). Overall, we identified 558 up-regulated and 405 down-regulated transcripts in the adult compared to the juvenile scorpions, of which 397 and 269 unique unigenes were annotated, respectively. GO and KEGG enrichment analyses indicated that the metabolic, thermogenesis, cytoskeleton, estrogen signaling, GnRH signaling, growth hormone signaling, and melanogenesis pathways were affected by two different growth conditions and the results suggested that the DE genes related to those pathways are important genes associated with scorpion venom gland development, in which they may be important in future studies, including Chs, Elovl, MYH, RDX, ACTN, VCL, PIP5K, PP1C, FGFR, GNAS, EGFR, CREB, CoA, PLCB, CALM, CACNA, PKA and CAMK genes.Conclusions: These findings broadened our knowledge of the differences between adult and juvenile scorpion venom and opened new perspectives on the application of comparative transcriptome analysis to identify the special key genes.

Venom hyaluronidase is an enzyme belonging to the glycoside hydrolase family that plays a critical role in systemic envenomation by spreading toxins in tissue and destruction of the extracellular matrix. The roles of venom hyaluronidase during envenomation have been widely studied, but the identification of its variants and isoforms is still under investigation. In this study, we developed a filtering method to identify the exon-intron pattern, alternative splicing events and isoforms of hyaluronidase in A. crassicauda and H. lepturus scorpions using the RNA-seq technique. Furthermore, in silico analysis was performed to identify and characterize the hyaluronidases. The most important findings were that the scorpion hyaluronidase gene contains 5 exons, 4 introns and undergo to alternative splicing events. In A. crassicauda and H. lepturus datasets, a sequence denominated AcHase-1 and three denominated HLHase1, HLHase2 and HLHase3 were identified as hyaluronidase variants respectively, which were found to have multiple isoforms that differed in the coding, non-coding or untranslated regions. The results showed that exon skipping, intron retention and alternative 3' splice site led to dysregulation of gene expression. To clarify the evolutionary history of scorpions based on hyaluronidase molecular phylogenetic studies, we used the phylogenetic tree to deduce the origins of this protein in different species of scorpions, spiders and bees. Hyaluronidase gene performed well for divergences and accurately separated closely related species. Our work provides insights into the diversity of Hase proteins during scorpion evolution and may direct further studies consisting of synthesis, purification and recombinant production of Hase proteins.

Scorpion stings are a significant public health concern globally, particularly in tropical and subtropical regions. Scorpion venoms contain a diverse array of bioactive peptides, and different scorpion species around the world typically exhibit varying venom profiles, resulting in a wide range of envenomation symptoms. Despite their harmful effects, scorpion venom peptides hold immense potential for drug development due to their unique characteristics. Therefore, the establishment of a comprehensive database that catalogs scorpions along with their known venom peptides and proteins is imperative in furthering research efforts in this research area. We hereby present ScorpDb, a novel database that offers convenient access to data related to different scorpion species, the peptides and proteins found in their venoms, and the symptoms they can cause. To this end, the ScorpDb database has been primarily advanced to accommodate data on the Iranian scorpion fauna. From there, we propose future community efforts to include a larger diversity of scorpions and scorpion venom components. ScorpDb holds the promise to become a valuable resource for different professionals from a variety of research fields, like toxinologists, arachnologists, and pharmacologists. The database is available at https://www.scorpdb.com/.

The potential function of long non-coding RNAs in regulating neighbor protein-coding genes has attracted scientists’ attention. Despite the important role of lncRNAs in biological processes, a limited number of studies focus on non-model animal lncRNAs. In this study, we used a stringent step-by-step filtering pipeline and machine learning-based tools to identify the specific Androctonus crassicauda lncRNAs and analyze the features of predicted scorpion lncRNAs. 13,401 lncRNAs were detected using pipeline in A. crassicauda transcriptome. The blast results indicated that the majority of these lncRNAs sequences (12,642) have no identifiable orthologs even in closely related species and those considered as novel lncRNAs. Compared to lncRNA prediction tools indicated that our pipeline is a helpful approach to distinguish protein-coding and non-coding transcripts from RNA sequencing data of species without reference genomes. Moreover, analyzing lncRNA characteristics in A. crassicauda uncovered that lower protein-coding potential, lower GC content, shorter transcript length, and less number of isoform per gene are outstanding features of A. crassicauda lncRNAs transcripts.

Background: Venom phospholipase D (PLDs), dermonecrotic toxins like, are the major molecules in the crude venom of scorpions, which are mainly responsible for lethality and dermonecrotic lesions during scorpion envenoming. The purpose of this study was fivefold: First, to identify transcripts coding for venom PLDs by transcriptomic analysis of the venom glands from Androctonus crassicauda, Hottentotta saulcyi, and Hemiscorpius lepturus; second, to classify them by sequence similarity to known PLDs and motif extraction method; third, to characterize scorpion PLDs; fourth to structural homology analysis with known dermonecrotic toxins; and fifth to investigate phylogenetic relationships of the PLD proteins. Results: We found that the venom gland of scorpions encodes two PLD isoforms: PLD1 ScoTox-beta and PLD2 ScoTox-alpha I. Two highly conserved regions shared by all PLD1s beta are GAN and HPCDC (HX2PCDC), and the most important conserved regions shared by all PLD2s alpha are two copies of the HKDG (HxKx4Dx6G) motif. We found that PLD1 beta is a 31–43 kDa acidic protein containing signal sequences, and PLD2 alpha is a 128 kDa basic protein without known signal sequences. The gene structures of PLD1 beta and PLD2 alpha contain 6 and 21 exons, respectively. Significant structural homology and similarities were found between the modeled PLD1 ScoTox-beta and the crystal structure of dermonecrotic toxins from Loxosceles intermedia. Conclusions: This is the first report on identifying PLDs from A. crassicauda and H. saulcyi venom glands. Our work provides valuable insights into the diversity of scorpion PLD genes and could be helpful in future studies on recombinant antivenoms production.

Effects of Different Levels of Zinc on the Performance and Carcass Characteristics of Broiler Rearedunder Heat Stress Condition