RESUMO
Scorpions, a seemingly primitive, stinging arthropod taxa, are known to exhibit marked diversity in their venom components. These venoms are known for their human pathology, but they are also important as models for therapeutic and drug development applications. In this study, we report a high-quality genome assembly and annotation of the striped bark scorpion, Centruroides vittatus, created with several shotgun libraries. The final assembly is 760â Mb in size, with a BUSCO score of 97.8%, a 30.85% GC, and an N50 of 2.35â Mb. We estimated 36,189 proteins with 37.32% assigned to Gene Ontology (GO) terms in our GO annotation analysis. We mapped venom toxin genes to 18 contigs and 2 scaffolds. We were also able to identify expression differences between venom gland (telson) and body tissue (carapace) with 19 sodium toxin and 14 potassium toxin genes to 18 contigs and 2 scaffolds. This assembly, along with our transcriptomic data, provides further data to investigate scorpion venom genomics.
Assuntos
Genoma , Anotação de Sequência Molecular , Escorpiões , Transcriptoma , Animais , Escorpiões/genética , Venenos de Escorpião/genética , Perfilação da Expressão Gênica , Genômica/métodos , Ontologia Genética , Animais PeçonhentosRESUMO
Over 400 million years old, scorpions represent an ancient group of arachnids and one of the first animals to adapt to life on land. Presently, the lack of available genomes within scorpions hinders research on their evolution. This study leverages ultralong nanopore sequencing and Pore-C to generate the first chromosome-level assembly and annotation for the desert hairy scorpion, Hadrurus arizonensis. The assembled genome is 2.23 Gb in size with an N50 of 280 Mb. Pore-C scaffolding reoriented 99.6% of bases into nine chromosomes and BUSCO identified 998 (98.6%) complete arthropod single copy orthologs. Repetitive elements represent 54.69% of the assembled bases, including 872,874 (29.39%) LINE elements. A total of 18,996 protein-coding genes and 75,256 transcripts were predicted, and extracted protein sequences yielded a BUSCO score of 97.2%. This is the first genome assembled and annotated within the family Hadruridae, representing a crucial resource for closing gaps in genomic knowledge of scorpions, resolving arachnid phylogeny, and advancing studies in comparative and functional genomics.
Assuntos
Genoma , Escorpiões , Animais , Escorpiões/genética , Cromossomos/genética , Filogenia , Anotação de Sequência Molecular , Evolução MolecularRESUMO
Phospholipase A2 is the most abundant venom gland enzyme, whose activity leads to the activation of the inflammatory response by accumulating lipid mediators. This study aimed to identify, classify, and investigate the properties of venom PLA2 isoforms. Then, the present findings were confirmed by chemically measuring the activity of PLA2. The sequences representing PLA2 annotation were extracted from the Androctonus crassicauda transcriptome dataset using BLAS searches against the local PLA2 database. We found several cDNA sequences of PLA2 classified and named by conducting multiple searches as platelet-activating factor acetylhydrolases, calcium-dependent PLA2s, calcium-independent PLA2s, and secreted PLA2s. The largest and smallest isoforms of these proteins range between approximately 70.34 kDa (iPLA2) and 17.75 kDa (cPLA2). Among sPLA2 isoforms, sPLA2GXIIA and sPLA2G3 with ORF encoding 169 and 299 amino acids are the smallest and largest secreted PLA2, respectively. These results collectively suggested that A. crassicauda venom has PLA2 activity, and the members of this protein family may have important biological roles in lipid metabolism. This study also revealed the interaction between members of PLA2s in the PPI network. The results of this study would greatly help with the classification, evolutionary relationships, and interactions between PLA2 family proteins in the gene network.
Assuntos
Fosfolipases A2 , Transcriptoma , Animais , Fosfolipases A2/genética , Fosfolipases A2/metabolismo , Escorpiões/genética , Sequência de Aminoácidos , Filogenia , Proteínas de Artrópodes/genética , Proteínas de Artrópodes/metabolismoRESUMO
The Brazilian scorpion Tityus melici, native to Minas Gerais and Bahia, is morphologically related to Tityus serrulatus, the most medically significant species in Brazil. Despite inhabiting scorpion-envenomation endemic regions, T. melici venom remains unexplored. This work evaluates T. melici venom composition and function using transcriptomics, enzymatic activities, and in vivo and in vitro immunological analyses. Next-Generation Sequencing unveiled 86 components putatively involved in venom toxicity: 39 toxins, 28 metalloproteases, seven disulfide isomerases, six hyaluronidases, three phospholipases and three amidating enzymes. T. serrulatus showed the highest number of toxin matches with 80-100 % sequence similarity. T. melici is of medical importance as it has a venom LD50 of 0.85 mg/kg in mice. We demonstrated venom phospholipase A2 activity, and elevated hyaluronidase and metalloprotease activities compared to T. serrulatus, paralleling our transcriptomic findings. Comparison of transcriptional levels for T. serrulatus and T. melici venom metalloenzymes suggests species-specific expression patterns in Tityus. Despite close phylogenetic association with T. serrulatus inferred from COI sequences and toxin similarities, partial neutralization of T. melici venom toxicity was achieved when using the anti-T. serrulatus antivenom, implying antigenic divergence among their toxins. We suggest that the Brazilian therapeutic scorpion antivenom could be improved to effectively neutralize T. melici venom.
Assuntos
Animais Peçonhentos , Venenos de Escorpião , Toxinas Biológicas , Camundongos , Animais , Transcriptoma , Sequência de Aminoácidos , Escorpiões/genética , Brasil , Peçonhas , Antivenenos , Filogenia , Hialuronoglucosaminidase/genética , Hialuronoglucosaminidase/metabolismo , Perfilação da Expressão Gênica , Venenos de Escorpião/genética , Venenos de Escorpião/metabolismoRESUMO
Scorpion venoms contain bioactive peptides and proteins. Some, can be used for pharmaceutical purposes. So, identification of venom proteins matters because, in addition to determining the function of the toxins can also be an excellent guide to developing new drugs. Here, we got transcriptome of venom glands from four Iranian scorpion species, including Hemsicorpius lepturus, Mesobuthus eupeus, Andructunus crassicuada, and Hottentotta saulcyi using cDNA library synthesis and high-throughput transcriptomic analysis of the venom glands. In a comparative way, we identified the cDNA encoding isoforms of subunits (alpha and beta) of BotLVP1/BmLVP1-like protein in the venom gland of three species except for H. lepturus. Characterization and structure determination of the LVP1_like proteins combined with gene map analysis provided evidence of the existence of some isoforms of LVP1_like proteins, encoded by genes with two exons and one intron, which can be classified in CSαß superfamily in the venom gland of three Iranian scorpion species. According to the high similarity with BotLVP1 and BmLVP1, these proteins could also be potent to mediate cholesterol homeostasis. However, further research is needed to prove it, and this study just may lay the foundation lead to light up this way.
Assuntos
Venenos de Escorpião , Escorpiões , Animais , Escorpiões/genética , Sequência de Aminoácidos , Irã (Geográfico) , Isoformas de Proteínas/metabolismo , Venenos de Escorpião/químicaRESUMO
The yellow digger scorpion, Scorpio maurus, is a medically important scorpion for which little is known about its genetic diversity. Polymerase chain reaction products of 16srRNA gene fragments were generated from scorpion specimens named SmKh1 and SmKh2. These sequences showed high similarity with the only partial sequence of S. maurus isolate SCA1 large subunit ribosomal RNA gene available in the Genbank database. The drawing of the phylogeny tree showed two clusters, A and B. The two specimens (SmKh1 and SmKh2), which are placed in sub-cluster A2, were provided from Behbahan, Iran, and they have the closest relationship with the only sequence of S. maurus (MW281771), which is also collected from Behbahan. It is noteworthy that the two sequences obtained from S. maurus scorpions recorded from Miandoab (MK170444) and Mahabad (KU705354), which are in sub-cluster A1, are more similar to the scorpions isolated from the Mediterranean basin than those collected from Behbahan. This issue is probably due to the fact that patterns of genetic diversity are a reflection of variation in gene flow, which is also influenced by factors such as territorial barriers and geographical distances. We conclude that the scorpions of this study accompanied by similar scorpions in the Mediterranean basin, belong to the same species despite the insignificant differences.
Assuntos
Animais Peçonhentos , Medicamentos de Ervas Chinesas , Variação Genética , Escorpiões , Animais , Escorpiões/genética , Irã (Geográfico)RESUMO
A synopsis on the historical, geographical and ecological aspects related to the most conspicuous scorpion species of the genus Tityus known from Brazil is proposed. Tityus serrulatus Lutz & Mello, 1922 was described precisely one century ago, nevertheless many questions related to its ecological adaptations and geographical expansion remain without a precise response. This species, well known for its infamous reputation of noxious species, is also known for its capacity to reproduce asexually, by parthenogenesis. Although the individuals of a given population are considered clones, a new hypothesis could suggest the occurrence of mutations within isolated individuals, leading to distinct subpopulations that could present better phenotypic performances in ecological habitats distinct from those of the original area of distribution of the species.(AU)