Effects of the venom of a Mygalomorph spider (Lasiodora sp.) on the isolated rat heart

Taxonomic revision and cladistic analysis of Lasiodora C. L. Koch, 1850 (Araneae, Theraphosidae) with notes on related genera

The genus Lasiodora C. L. Koch, 1850 is revised and morphological cladistic analyses carried out including all of its species, as well as most of those of the related genera Vitalius Lucas, Silva & Bertani, 1993, Nhandu Lucas, 1983, Pterinopelma Pocock, 1901, Proshapalopus Mello-Leito, 1923, Eupalaestrus Pocock, 1901, Lasiocyano Galleti-Lima, Hamilton, Borges & Guadanucci, 2023, Parvicarina Galleti-Lima, Hamilton, Borges & Guadanucci, 2023, and Tekoapora Galleti-Lima, Hamilton, Borges & Guadanucci, 2023. A matrix with 50 terminal taxa, 2 continuous and 48 discrete characters was analyzed with TNT 1.5. The result shows a monophyletic Lasiodora as sister group of Nhandu, and Vitalius is the sister group of this clade. Lasiodora comprises 7 species: Lasiodora klugi (C. L. Koch, 1841) (type species), L. benedeni Bertkau, 1880, L. parahybana Mello-Leito, 1917, L. subcanens Mello-Leito, 1921, L. camurujipe n. sp., L. sertaneja n. sp., and L. franciscana n. sp. Lasiodora itabunae Mello-Leito, 1921 is considered a junior synonym of L. klugi. Lasiodora differens Chamberlin, 1917, L. curtior Chamberlin, 1917, L. mariannae Mello-Leito, 1921, L. difficilis Mello-Leito, 1921, L. erythrocythara Mello-Leito, 1921, and Acanthoscurria cristata Mello-Leito, 1923 are considered junior synonyms of L. benedeni. Lasiodora acanthognatha Mello-Leito, 1921 is considered junior synonym of L. parahybana. Lasiodora dulcicola Mello-Leito, 1921 is considered junior synonym of L. subcanens. Nhandu sylviae Sherwood, Gabriel & Brescovit, 2023 is considered junior synonym of Vitalius sorocabae Mello-Leito, 1923. The holotype of Crypsidromus isabellinus Ausserer, 1871 (type species of the genus) was reanalyzed and is considered the senior synonym of Proshapalopus anomalus Mello-Leito, 1923 (type species of the genus). Thus, the genus Crypsidromus Ausserer, 1871 is considered valid, removed from the synonymy with Lasiodora, and Proshapalopus is considered a junior synonym of Crypsidromus. The new combination C. multicuspidatus (Mello-Leito, 1929) n. comb. is established. Crypsidromus bolivianus Simon, 1892 is considered a junior synonym of Acanthoscurria insubtilis Simon, 1892. Five species from Costa Rica described in Crypsidromus are transferred back from Lasiodora: Crypsidromus brevibulbus Valerio, 1980 comb. rev., C. carinatus Valerio, 1980 comb. rev., C. icecu Valerio, 1980 comb. rev., C. puriscal Valerio, 1980 comb. rev., C. rubitarsus Valerio, 1980 comb. rev. Lasiodora lakoi Mello-Leito, 1943 is transferred to Megaphobema, making the new combination Megaphobema lakoi (Mello-Leito, 1943) n. comb. Lasiodora spinipes Ausserer, 1871 is transferred to Theraphosa, making the new combination Theraphosa spinipes (Ausserer, 1871) n. comb. Nhandu chromatus Schmidt, 2004 is transferred to Vitalius making the new combination Vitalius chromatus (Schmidt, 2004) n. comb. Lasiodora sternalis is transferred to Acanthoscurria making the new combination Acanthoscurria sternalis (Mello-Leito, 1923). Due to the homonymy with Acanthoscurria sternalis Pocock, 1903, the new name Acanthoscurria melloleitaoi nom. nov. is proposed. The following species are considered nomina dubia: Lasiodora saeva (Walckenaer, 1837), Lasiodora striatipes (Ausserer, 1871), Lasiodora moreni (Holmberg, 1876), Crypsidromus fallax Bertkau, 1880, Trechona pantherina Keyserling, 1891, Lasiodora bahiensis Strand, 1907, Lasiodora citharacantha Mello-Leito, 1921, Lasiodora cryptostigma Mello-Leito, 1921, Lasiodora dolichosterna Mello-Leito, 1921, Lasiodora fracta Mello-Leito, 1921, and Lasiodora pleoplectra Mello-Leito, 1921. A discussion on the relationship of Lasiodora, Nhandu, Vitalius, Pterinopelma and Crypsidromus as well maps with the distributions of all Lasiodora species are provided.

Brazilian Theraphosidae: a toxicological point of view

The Theraphosidae family includes the largest number of species of the Mygalomorphae infraorder, with hundreds of species currently catalogued. However, there is a huge lack on physiologic and even ecologic information available, especially in Brazil, which is the most biodiverse country in the world. Over the years, spiders have been presented as a source of multiple biologically active compounds with basic roles, such as primary defense against pathogenic microorganisms or modulation of metabolic pathways and as specialized hunters. Spider venoms also evolved in order to enable the capture of prey by interaction with a diversity of molecular targets of interest, raising their pharmaceutical potential for the development of new drugs. Among the activities found in compounds isolated from venoms and hemocytes of Brazilian Theraphosidae there are antimicrobial, antifungal, antiparasitic and antitumoral, as well as properties related to proteinase action and neuromuscular blockage modulated by ionic voltage-gated channel interaction. These characteristics are present in different species from multiple genera, which is strong evidence of the important role in spider survival. The present review aims to compile the main results of studies from the last decades on Brazilian Theraphosidae with special focus on results obtained with the crude venom or compounds isolated from both venom and hemocytes, and their physiological and chemical characterization.

ADP is a vasodilator component from Lasiodora sp. mygalomorph spider venom

Members of the spider genus Lasiodora are widely distributed in Brazil, where they are commonly known as caranguejeiras. Lasiodora spider venom is slightly harmful to humans. The bite of this spider causes local pain, edema and erythema. However, Lasiodora sp. spider venom may be a source of important pharmacological tools. Our research group has described previously that Lasiodora sp. venom produces bradycardia in the isolated rat heart. In the present work, we sought to evaluate the vascular effect of Lasiodora sp. venom and to isolate the vasoactive compounds from the venom. The results showed that Lasiodora spider venom induced a concentration-dependent vasodilation in rat aortic rings, which was dependent on the presence of a functional endothelium and abolished by the nitric oxide synthase (NOS) inhibitor L-NAME. Western blot experiments revealed that the venom also increased endothelial NOS function by increasing phosphorylation of the Ser¹¹⁷⁷ residue. Assay-directed fractionation isolated a vasoactive fraction from Lasiodora sp. venom. Mass spectrometry (MS) and nuclear magnetic resonance (NMR) assays identified a mixture of two compounds: adenosine diphosphate (ADP, approximately 90%) and adenosine monophosphate (AMP, approximately 10%). The vasodilator effects of Lasiodora sp. whole venom, as well as ADP, were significantly inhibited by suramin, which is a purinergic P2-receptor antagonist. Therefore, the results of the present work indicate that ADP is a main vasodilator component of Lasiodora sp. spider venom.

Expression and characterization of LTx2, a neurotoxin from Lasiodora sp. effecting on calcium channels

Here, we described the expression and characterization of the recombinant toxin LTx2, which was previously isolated from the venomous cDNA library of a Brazilian spider, Lasiodora sp. (Mygalomorphae, Theraphosidae). The recombinant toxin found in the soluble and insoluble fractions was purified by reverse phase high-performance liquid chromatography (HPLC). Ca2+ imaging analysis revealed that the recombinant LTx2 acts on calcium channels of BC3H1 cells, blocking L-type calcium channels.

Peptide profiling by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry of the Lasiodora parahybana tarantula venom gland

In order to establish a venom fingerprint and a peptide profile of the Lasiodora parahybana tarantula venom gland, we used conventional methods such as reversed phase liquid chromatography coupled to an electrospray-ionisation hybrid quadrupole time of flight mass spectrometer (LC/ESI-QqTOFMS), matrix-assisted laser desorption/ionization time-of-flight-MS (MALDI-TOFMS) and direct study of L. parahybana venom by nanospray-ionization QqTOFMS (nanoESI-QqTOFMS) and a new technology for the direct analysis of fresh tissues using MALDI-TOFMS. The analysis of the crude venom allowed the characterization of specific juvenile and adult biomarkers. In situ MALDI analysis of L. parahybana venom gland sections revealed different peptide expression levels all along the gland and non-processed peptide precursors, demonstrating the power of the method for the dynamic investigation of peptide evolution in the venom gland of spiders.

Functional structure of Agelena labyrinthica's (Araneae:Agelenidae) venom gland and electrophoresis of venom

The funnel-web spider, Agelena labyrinthica, is widely distributed throughout Turkey. The objective of the present study was to describe the histological and functional fine structure of A. labyrinthica's venom gland by using light microscope, scanning (SEM) and transmission electron microscope (TEM). We have also preliminarily analyzed venom components by SDS-PAGE. Each venom gland has surrounded by a thin adventitia and gross striated muscular bundles. Basal lamina underlies between muscular bundles and the inner glandular epithelium, and ties up them each other. The striated muscular bundles spirally covered venom gland has been observed by SEM. Intricate relations formed between motor neuron axons and the muscle fibers have been revealed by TEM. The secretory epithelium, which made up of simple columnar cells, formed the secretory region of the venom gland. The secretory surface of the gland was increased by a sort of fringes extended from basal membrane into the gland lumen. The epithelial cells have many rough endoplasmic reticulum, mitochondria and different size and shape of secretory granules. These granules have been accumulated in apical portion of the secretory cells. After the gland is emptied, the apical portions of secretory cells deteriorate and the basal epithelial cells regenerate the columnar cells. The analysis of A. labyrinthica venom, which was achieved by SDS-PAGE showed that there have been at least seven components ranging from 10 to 40 kDa molecular weight.

Molecular cloning of toxins expressed by the venom gland of Lasiodora sp

The present work describes the identification of toxins expressed by the venom gland of the spider Lasiodora sp. The toxins LTx1, LTx2 and LTx3 were identified by the screening of a cDNA library. These toxins showed significant similarity at the amino acid level with spider toxins from Lasiodora parahybana, Eurypelma californicum, Brachypelma smithii, Selenocosmia huwena.