Spider venom peptides Ht1a and Gg1a are toxic to honeybee parasite Varroa destructor by topical application

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  Spider venom peptides Ht1a and Gg1a are toxic to honeybee parasite Varroa destructor by topical application Abstract Global food supply strongly depends on honeybee pollination services, which are threatened by insecticides and pests such as parasitic Varroa destructor mites. Chemical varroacides/acaricides are hampered by resistance development, necessitating the development of sustainable and environmentally friendly alternatives, with arthropod venom peptides being considered promising sources of acaricidal toxins. With only a few acaricidal venom peptides being reported, we performed a systematic topical screening of 50 arthropod venoms against V. destructor , with 78% of the venoms causing 100% mortality after 24 h. Deconvolution of the venoms from the Tasmanian cave spider Hickmania troglodytes and the Giant Japanese funnel-web spider Gigathele gigas led to identification of the varroacidal peptides Ht1a and Gg1a. Topical application of Ht1a and Gg1a reduced varroa mite ...

Karyotype and genome characterization analysis of Chilobrachys jingzhao (Theraphosidae: Chilobrachys)

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Karyotype and genome characterization analysis of Chilobrachys jingzhao (Theraphosidae: Chilobrachys)

Abstract

The medicinal preparation of Chilobrachys jingzhao possesses various therapeutic properties, including anti-inflammatory, detoxifying, analgesic, and anti-edema effects. However, research on its genetic background and toxin mechanisms is held back by the lack of chromosome karyotype and genome data. In this study, we analyzed the karyotype of C. jingzhao using chromosome preparation techniques, estimated the genome size using flow cytometry and K-mer analysis, and performed genome sequencing and assembly using second- and third-generation single molecule real-time sequencing technologies. The results showed that C. jingzhao has a diploid chromosome number of 2n=68, with a karyotype formula of 2n=46m+18sm+4st and a chromosomal complement of 2n=10L+18M2+38M1+2S. Using Solanum lycopersicum and Trichonephila clavata as references, flow cytometry estimates the genome size at 7,775.49 Mb and 7,680.26 Mb, respectively. The 19-mer analysis also estimated the genome size to be 7,626.00 Mb, consistent with the flow cytometry results. Further analysis indicated that the genome of C. jingzhao has a high level of heterozygosity (8.45%) and a high proportion of repetitive sequences (67.10%), classifying it as an ultra-high heterozygous and high-repeat genome. The initial genome assembly of C. jingzhao was 8,804.93 Mb in size, with a contig N50 of 55.55 Mb and a BUSCO completeness score of 95.9%, indicating high assembly quality. This study first reveals the karyotype and genome information of C. jingzhao, offering crucial data for future research on its whole genome, toxin mechanisms, genetics, origin, evolution, and taxonomy.

Yuxuan Zhang, Mengying Zhang, Hanting Yang, Chi Song, Zizhong Yang, Shilin Chen. Karyotype and genome characterization analysis of Chilobrachys jingzhao (Theraphosidae: Chilobrachys)[J]. Hereditas(Beijing), 2025, 47(12): 1351-1364.https://www.chinagene.cn/EN/10.16288/j.yczz.25-026