Phylogenetic analyses suggest centipede venom arsenals were repeatedly stocked by horizontal gene transfer.

Venoms have evolved over a hundred times in animals. Venom toxins are thought to evolve mostly by recruitment of endogenous proteins with physiological functions. Here we report phylogenetic analyses of venom proteome-annotated venom gland transcriptome data, assisted by genomic analyses, to show that centipede venoms have recruited at least five gene families from bacterial and fungal donors, involving at least eight horizontal gene transfer events. These results establish centipedes as currently the only known animals with venoms used in predation and defence that contain multiple gene families derived from horizontal gene transfer. The results also provide the first evidence for the implication of horizontal gene transfer in the evolutionary origin of venom in an animal lineage. Three of the bacterial gene families encode virulence factors, suggesting that horizontal gene transfer can provide a fast track channel for the evolution of novelty by the exaptation of bacterial weapons into animal venoms.

Variation in venom yield and protein concentration of the centipedes Scolopendra polymorpha and Scolopendra subspinipes.

Venom generally comprises a complex mixture of compounds representing a non-trivial metabolic expense. Accordingly, natural selection should fine-tune the amount of venom carried within an animal's venom gland(s). The venom supply of scolopendromorph centipedes likely influences their venom use and has implications for the severity of human envenomations, yet we understand very little about their venom yields and the factors influencing them. We investigated how size, specifically body length, influenced volume yield and protein concentration of electrically extracted venom in Scolopendra polymorpha and Scolopendra subspinipes. We also examined additional potential influences on yield in S. polymorpha, including relative forcipule size, relative mass, geographic origin (Arizona vs. California), sex, time in captivity, and milking history. Volume yield was linearly related to body length, and S. subspinipes yielded a larger length-specific volume than S. polymorpha. Body length and protein concentration were uncorrelated. When considering multiple influences on volume yield in S. polymorpha, the most important factor was body length, but yield was also positively associated with relative forcipule length and relative body mass. S. polymorpha from California yielded a greater volume of venom with a higher protein concentration than conspecifics from Arizona, all else being equal. Previously milked animals yielded less venom with a lower protein concentration. For both species, approximately two-thirds of extractable venom was expressed in the first two pulses, with remaining pulses yielding declining amounts, but venom protein concentration did not vary across pulses. Further study is necessary to ascertain the ecological significance of the factors influencing venom yield and how availability may influence venom use.

Nuevos conceptos en la fabricación de extractos de veneno de himenópteros / New concepts in the manufacture of Hymenoptera venom extracts

A lo largo del siglo XX se produjeron importantes avances clínicos en el tratamiento de la alergia a himenópteros. En un principio se utilizaron extractos de cuerpo completo de abeja como diagnóstico y tratamiento de pacientes sensibles a este insecto, más tarde se describió que la utilización de extractos de veneno de himenópteros era mucho más eficaz que los cuerpos completos y, por último, la aplicación de técnicas de biología molecular ha permitido ensayar nuevos tipos de tratamientos con proteínas recombinantes, cuyo perfil de seguridad y eficacia es similar al de los extractos de veneno. Todos estos avances clínicos han hecho cambiar de una manera significativa los criterios de fabricación de los extractos alergénicos en general y en particular el de los extractos de himenópteros, no solo por el ingrediente activo utilizado en la producción de extractos (cuerpo completo, veneno o proteína pura) o por los procesos de estandarización y de control de calidad empleados, sino también por la aplicación a los sistemas de producción de requerimientos farmacéuticos como las Normas de Correcta Fabricación (GMP's), que garantizan el control de las instalaciones, equipos, documentación, validación de los procesos y, por tanto, la consistencia de los productos para uso clínico (AU)

Toxins produced by arthropod parasites: salivary gland proteins of human body lice and venom proteins of chelonine wasps.

A review is presented of our ongoing research projects on the protein components of the saliva of human body lice and of the non-paralyzing venom of wasps in the subfamily Cheloninae. Sodium dodecyl sulfate-polyacryamide gel electrophoretic analysis of lice salivary gland proteins showed a predominance of high and intermediate mol. wt proteins. Immunoblotting with a low titer polyclonal antiserum to lice salivary proteins indicated that some, but not all, of the predominant high mol. wt salivary gland proteins are injected into the host during feeding. The venom of a Chelonus sp. wasp contains a chitinase, and a 33,000 mol. wt protein with a primary structure composed mostly of a series of 12 tandem repeats of a 14-residue sequence. The N-terminus of this protein and its homologs in a related species of Ascogaster share a conserved adjacent pair of acidic residues. Epitope mapping/immunoprecipitation experiments now in progress will provide information on which linear motifs are on the surface of the protein, and will thereby provide information on the tertiary structure of the protein.

Molecular cloning and characterization of a major allergen (Myr p I) from the venom of the Australian jumper ant, Myrmecia pilosula.

Five IgE-binding components were identified in the venom of the Australian jumper ant, Myrmecia pilosula using SDS polyacrylamide gel electrophoresis and Western blotting. A cDNA clone which encodes the entire amino acid sequence of one of the major IgE-binding venom allergens has been nucleotide sequenced. The IgE-binding determinants of this allergen are located in its C-terminal domain. Database searches, however, did not reveal any homology with any other known nucleotide or protein sequence. The sequenced allergenic polypeptide has, according to the convention recommended by the International Union of Immunological Societies (IUIS), been named Myr p I.

Alkaloid venom of European ants in the genus Monomorium. Site of synthesis, identification and quantification.

The venom of the European Ant Monomorium is composed of five alkaloids: three 2.5 transdialkylpyrrolidines and two 2.5 transdialkylpyrrolines. The venom is synthesized by a glandular complex composed of a biramous external filamentous gland, and a single internal gland invaginated into the reservoir. External glands and the proximal two-thirds of the internal gland are composed of glandular units, with one glandular cell and one associated duct cell. Glandular cells contain numerous giant mitochondria, a well-developed smooth endoplasmic reticulum and enigmatic rod-shaped structures. The secretory product is electron-lucent. The distal third of the internal gland is composed of 38-48 large secretory cells issuing directly into the reservoir. Their secretory product presents the same characteristics as the venom accumulated in the reservoir (opacity, affinity to stains and osmium).