Antimicrobial activity and partial chemical structure of acylpolyamines isolated from the venom of the spider Acanthoscurria natalensis

Background: Acylpolyamines are one of the main non-peptide compounds present in spider venom and represent a promising alternative in the search for new molecules with antimicrobial action. Methods: The venom of Acanthoscurria natalensis spider was fractionated by reverse-phase liquid chromatography (RP-HPLC) and the antimicrobial activity of the fractions was tested using a liquid growth inhibition assay. The main antimicrobial fraction containing acylpolyamines (ApAn) was submitted to two additional chromatographic steps and analyzed by MALDI-TOF. Fractions of interest were accumulated for ultraviolet (UV) spectroscopy and ESI-MS/MS analysis and for minimum inhibitory concentration (MIC) and hemolytic activity determination. Results: Five acylpolyamines were isolated from the venom with molecular masses between 614 Da and 756 Da, being named ApAn728, ApAn614a, ApAn614b, ApAn742 and ApAn756. The analysis of UV absorption profile of each ApAn and the fragmentation pattern obtained by ESI-MS/MS suggested the presence of a tyrosyl unit as chromophore and a terminal polyamine chain consistent with structural units PA43 or PA53. ApAn presented MIC between 128 µM and 256 µM against Escherichia coli and Staphylococcus aureus, without causing hemolysis against mouse erythrocytes. Conclusion: The antimicrobial and non-hemolytic properties of the analyzed ApAn may be relevant for their application as possible therapeutic agents and the identification of an unconventional chromophore for spider acylpolyamines suggests an even greater chemical diversity.(AU)

Widow spiders in the New World: a review on Latrodectus Walckenaer, 1805 (Theridiidae) and latrodectism in the Americas

Humankind has always been fascinated by venomous animals, as their toxic substances have transformed them into symbols of power and mystery. Over the centuries, researchers have been trying to understand animal venoms, unveiling intricate mixtures of molecules and their biological effects. Among venomous animals, Latrodectus Walckenaer, 1805 (widow spiders) have become feared in many cultures worldwide due to their extremely neurotoxic venom. The Latrodectus genus encompasses 32 species broadly spread around the globe, 14 of which occur in the Americas. Despite the high number of species found in the New World, the knowledge on these spiders is still scarce. This review covers the general knowledge on Latrodectus spp. from the Americas. We address widow spiders' taxonomy; geographical distribution and epidemiology; symptoms and treatments of envenomation (latrodectism); venom collection, experimental studies, proteome and transcriptome; and biotechnological studies on these Latrodectus spp. Moreover, we discuss the main challenges and limitations faced by researchers when trying to comprehend this neglected group of medically important spiders. We expect this review to help overcome the lack of information regarding widow spiders in the New World.(AU)

Brown spider venom toxins: what are the functions of astacins, serine proteases, hyaluronidases, allergens, TCTP, serpins and knottins?

Accidents caused by the bites of brown spiders (Loxosceles) generate a clinical condition that often includes a threatening necrotic skin lesion near the bite site along with a remarkable inflammatory response. Systemic disorders such as hemolysis, thrombocytopenia, and acute renal failure may occur, but are much less frequent than the local damage. It is already known that phospholipases D, highly expressed toxins in Loxosceles venom, can induce most of these injuries. However, this spider venom has a great range of toxins that probably act synergistically to enhance toxicity. The other protein classes remain poorly explored due to the difficulty in obtaining sufficient amounts of them for a thorough investigation. They include astacins (metalloproteases), serine proteases, knottins, translationally controlled tumor proteins (TCTP), hyaluronidases, allergens and serpins. It has already been shown that some of them, according to their characteristics, may participate to some extent in the development of loxoscelism. In addition, all of these toxins present potential application in several areas. The present review article summarizes information regarding some functional aspects of the protein classes listed above, discusses the directions that could be taken to materialize a comprehensive investigation on each of these toxins as well as highlights the importance of exploring the full venom repertoire.(AU)

Neuroactive venom compounds obtained from Phlogiellus bundokalbo as potential leads for neurodegenerative diseases: insights on their acetylcholinesterase and beta-secretase inhibitory activities in vitro

Spider venom is a rich cocktail of neuroactive compounds designed to prey capture and defense against predators that act on neuronal membrane proteins, in particular, acetylcholinesterases (AChE) that regulate synaptic transmission through acetylcholine (ACh) hydrolysis - an excitatory neurotransmitter - and beta-secretases (BACE) that primarily cleave amyloid precursor proteins (APP), which are, in turn, relevant in the structural integrity of neurons. The present study provides preliminary evidence on the therapeutic potential of Phlogiellus bundokalbo venom against neurodegenerative diseases. Methods Spider venom was extracted by electrostimulation and fractionated by reverse-phase high-performance liquid chromatography (RP-HPLC) and characterized by matrix-assisted laser desorption ionization-time flight mass spectrometry (MALDI-TOF-MS). Neuroactivity of the whole venom was observed by a neurobehavioral response from Terebrio molitor larvae in vivo and fractions were screened for their inhibitory activities against AChE and BACE in vitro. Results The whole venom from P. bundokalbo demonstrated neuroactivity by inducing excitatory movements from T. molitor for 15 min. Sixteen fractions collected produced diverse mass fragments from MALDI-TOF-MS ranging from 900-4500 Da. Eleven of sixteen fractions demonstrated AChE inhibitory activities with 14.34% (± 2.60e-4) to 62.05% (± 6.40e-5) compared with donepezil which has 86.34% (± 3.90e-5) inhibition (p > 0.05), while none of the fractions were observed to exhibit BACE inhibition. Furthermore, three potent fractions against AChE, F1, F3, and F16 displayed competitive and uncompetitive inhibitions compared to donepezil as the positive control. Conclusion The venom of P. bundokalbo contains compounds that demonstrate neuroactivity and anti-AChE activities in vitro, which could comprise possible therapeutic leads for the development of cholinergic compounds against neurological diseases.(AU)

Acute kidney injury due to systemic Loxoscelism: a cross-sectional study in Northeast Brazil

Abstract INTRODUCTION: Loxoscelism is a clinical condition involving spiders of the genus Loxosceles. One of the most severe complications is acute kidney injury (AKI). This study aimed to investigate AKI and other complications associated with loxoscelism. METHODS: We analyzed cases diagnosed with loxoscelism in an area where most accidents were caused by Loxosceles amazonica from January 2010 to December 2015. AKI was defined according to the KDIGO criteria. RESULTS: Forty-five patients were recorded: 95.6% presented characteristic necrotic skin lesions and 13.3% AKI. CONCLUSIONS: Loxoscelism could cause kidney involvement which is uncommon and could lead to the death of these patients.

Heterophilic antibodies in sera from individuals without loxoscelism cross-react with phospholipase D from the venom of Loxosceles and Sicarius spiders

Loxoscelism is a severe human envenomation caused by Loxosceles spider venom. To the best of our knowledge, no study has evaluated the presence of antibodies against Loxosceles venom in loxoscelism patients without treatment with antivenom immunotherapy. We perform a comparative analysis for the presence of antibodies capable of recognizing Loxosceles venom in a group of patients diagnosed with loxoscelism and in a group of people without loxoscelism. Methods The detection of L. laeta venom, Sicarius venom and recombinant phospholipases D from Loxosceles (PLDs) in sera from people with loxoscelism (Group 1) and from healthy people with no history of loxoscelism (Group 2) was evaluated using immuno-dot blot, indirect ELISA, and Western blot. Results We found naturally heterophilic antibodies (IgG-type) in people without contact with Loxosceles spiders or any clinical history of loxoscelism. Either serum pools or single sera from Group 1 and Group 2 analyzed by dot blot tested positive for L. laeta venom. Indirect ELISA for venom recognition showed titles of 1:320 for Group 1 sera and 1:160 for Group 2 sera. Total IgG quantification showed no difference in sera from both groups. Pooled sera and purified IgG from sera of both groups revealed venom proteins between 25 and 32 kDa and the recombinant phospholipase D isoform 1 (rLlPLD1), specifically. Moreover, heterophile antibodies cross-react with PLDs from other Loxosceles species and the venom of Sicarius spider. Conclusions People without contact with the spider venom produced heterophilic antibodies capable of generating a cross-reaction against the venom of L. laeta and Sicarius spiders. Their presence and possible interference should be considered in the development of immunoassays for Loxosceles venom detection.(AU)

Neurotoxic activity and ultrastructural changes in muscles caused by the brown widow spider Latrodectus geometricus venom / Actividad neurotóxica y cambios ultraestructurales en musculos causados por el veneno de la araña viuda marrón Latrodectus geometricus

Brown widow spider (Latrodectus geometricus) venom (BrWSV) produces few local lesions and intense systemic reactions such as cramps, harsh muscle pains, nausea, vomiting and hypertension. Approximately 16 protein bands under reducing conditions and ~ 14 bands under non-reducing conditions on a 12.5% sodium dodecyl sulfate-polyacrylamide gel electrophoresis were observed. Neurotoxic clinical manifestations were confirmed in vivo, while proteolytic activity was demonstrated on gelatine film. Severe ultrastructural damages in mice skeletal muscles were observed at 3, 6, 12 and 24 h postinjection with at total of 45 µg of venom protein. Infiltration of eosinophils and ruptures of the cellular membranes were observed in the muscles along with swelling of the nuclear cover and interruption of the collagen periodicity. Altered mitochondrias and autophage vacuoles, nuclear indentation and mitochondria without cristae, slight increment of intermyofibrillar and subsarcolemic spaces and myelinic figures formation were also observed. In the capillary, endothelial membrane unfolding into the lumen was noticed; along with myelinic figures compatible with a toxic myopathy. Swollen sarcotubular systems with lysis of membrane, intense mitochondria autophagia and areas without pinocytic vesicles were observed. Swollen mitochondria surrounded by necrotic areas, myofibrillar disorganization and big vacuolas of the sarcotubular system, degenerated mitochondrium with formation of myelinic figure was seen. Glycogenosomes with small particulate, muscle type glycogen was noticed. Autophagic vacuole (autophagolysosomes) and necrotic areas were also noticed. These damages may be due to interactive effects of the multifactorial action of venom components. However, Latrodectus geometricus venom molecules may also be utilized as neuro therapeutic tools, as they affect neuronal activities with high affinity and selectivity. To our knowledge, the present study...

El veneno de la araña viuda marrón (Latrodectus geometricus) produce pocas lesiones locales pero intensas reacciones sistémicas, tales como calambres, dolores musculares severos, nauseas, vómitos e hipertensión arterial. Se observaron ~ 16 bandas de proteina bajo condiciones reducidas y ~14 bandas bajo condiciones no reducidas en electroforesis en geles de poliacrilamida al 12.5%. Las manifestaciones neurotóxicas clínicas fueron confirmadas in vivo, mientras que la actividad proteolítica fue demostrada en una placa de gelatina. Los músculos de ratón se estudiaron durante las 3, 6, 12 y 24 horas después de ser inyectados con 45 µg de proteina de veneno. Los músculos fueron seriamente dañados por este veneno. Se demostró una infiltracción de células eosinofílicas y rupturas de membranas celulares en tejido muscular, al mismo tiempo un fuerte incremento de la membrana nuclear y una interrupción de la periodicidad del colágeno. Se observaron daños en la mitocondria y sin cristaes, vacuolas autofágicas e indentación nuclear. Se notó un aumento de la luz de los espacios intermiofibrilares y subsarcolemicos. En los capilares fue visible un desdoblamiento de la membrana endotelial hacia el lúmen vascular. Del mismo modo, fue visto un hinchamiento del sistema sarcotubular con lisis de las membranas; intensa autofagia de mitocondrias y áreas sin vesículas pinocíticas. Fue además observado, glucogenosomas con glucogeno particulado. Se observaron vacuolas autofágicas (autofagolisosomas) y áreas de necrosis. Estos daños podrían ser atribuídos a los efectos interactivos de una acción multifactorial de los componentes del veneno.

Estudo taxonômico das espécies não-amazônicas do gênero Phoneutria perty, 1833 (Araneae, Ctenidae)

As espécies não-amazônicas do gênero Phoneutria perty, 1833, são revisadas. Essas aranhas são conhecidas no Brasil como aranhas-armadeiras ou "armed spider", "Brazilian wandering spider" ou "banana-spider" em países de língua inglesa. São ctenídeos caracterizados por apresentar escópula ventral na tíbia e no tarso dos palpos. O veneno possui ação neurotóxica e são responsáveis por grande parte dos acidentes notifidacos no Brasil, considerados uma das formas mais comuns de araneísmo. Phoneutria luederwaldti Mello-Leitção, 1927 é considerada "nomen dubium". As espécies P. keyserlingi e P. pertyi que haviam sido sinonimizadas com P. nigriventer são consideradas válidas. São apresentadas a re-descrição de macho e fêmea das espécies não-amazônicas e a descrição do macho P. pertyi. As espécies P. nigriventer, P. Keyserlingi, P. pertyl e P. bahiensis são re-diagnosticadas. Uma espécie nova é descrita para o Brasil: P. eickstedtae. O gênero Phoneutria, passa a incluir oito espécies: P. fera Perty, 1833, P. reidyi Pickard-Cambridge, 1897, P. boliviensis Pickard-Cambrige, 1897, P. bahiensis Simó & Brescovlit, 2001, P. pertyi sp. rev (Pickard-Cambrige, 1897), P. keyserlingi sp. rev. (Pickard-Cambrige, 1897), P. nigriventer Keyserling, 1891 e Phoneutria eickstedtae sp. nov. Mapas com a distribuição geográfica das espécies não-amazônicas são apresentados. Essas espécies ocorrem em, áreas florestadas da Mata Atlântica e fragmentos de mata do Cerrado. A distribuição de P. bahiensis é ampliada para o norte do Estado do Espírito Santo e de P. pertyi para o Estado do Espírito Santo e sul da Bahia. Uma nova chave de identificação é apresentada para todas as espécies de Phoneutria.

Extracellular matrix molecules as targets for brown spider venom toxins

Loxoscelism, the term used to describe lesions and clinical manifestations induced by brown spider's venom (Loxosceles genus), has attracted much attention over the last years. Brown spider bites have been reported to cause a local and acute inflammatory reaction that may evolve to dermonecrosis (a hallmark of envenomation) and hemorrhage at the bite site, besides systemic manifestations such as thrombocytopenia, disseminated intravascular coagulation, hemolysis, and renal failure. The molecular mechanisms by which Loxosceles venoms induce injury are currently under investigation. In this review, we focused on the latest reports describing the biological and physiopathological aspects of loxoscelism, with reference mainly to the proteases recently described as metalloproteases and serine proteases, as well as on the proteolytic effects triggered by L. intermedia venom upon extracellular matrix constituents such as fibronectin, fibrinogen, entactin and heparan sulfate proteoglycan, besides the disruptive activity of the venom on Engelbreth-Holm-Swarm basement membranes. Degradation of these extracellular matrix molecules and the observed disruption of basement membranes could be related to deleterious activities of the venom such as loss of vessel and glomerular integrity and spreading of the venom toxins to underlying tissues

Identification and neutralization of biological activities in the venoms of Loxosceles spiders

The biological activities of the venom of three species of spiders of the genus Loxosceles were studied (L. gaucho, L. laeta and L. intermedia). The dermonecrotic and lethal activities are shared by all three Loxosceles venoms. Only low levels of proteolytic, myotoxic and phospholipase A2 activities were demonstrable even when a large amount of venom was used. No direct hemolytic activitiy was detected. L. intermedia venom was the most lethal (LD50 0.48 mg/kg), the L. laeta venom was the least lethal (LD50 1.45 mg/kg) whereas L. gaucho venom showed an intermediate value (LD50 0.74 mg/kg). The anti-Loxosceles serum used (anti-arachnidic serum) was able to neutralize the most important activities (i.e., dermonecrotic and lethal activities) of the three venoms. SDS-PAGE and immunoblotting using the anti-arachnidic serum showed that almost all venom antigens were recognized by this antiserum. The possible mechanisms of action of the Loxosceles venom are discussed.

Latrodectismo / Latrodectism

Numerosas especies de artrópodos poseen veneno capaz de producir enfermedad en el ser humano. Por su severidad y frecuencia, debe destacarse la causa por arácnidos (aracnidismo), especialmente la producida por el género Latrodectus (Orden Araneida), capaz de desencadenar un cuadro neurotóxico grave, denominado latrodectismo. En este artículo se revisan los aspectos biológicos, clínicos y terapéuticos más relevantes de esta patología

Partial purification and pharmacological characterization of a neurotoxic fraction isolet from the venom of the spider Lycosa erythrognatha

The effect of the venom of the spider Lycosa erythrognatha on the frog sciatic nerve was investigated with the single sucrose-gap method. Solutions containing the crude venom (40 µg protein/ml) markedly increased the duration of compound action potentials and caused the appearance of long-lasting depolarizing post-potentials. These effects were only partially (20 percent) reversded by extensive washsing with control solution. The active material was sensitive to proteolytic treatments with pronase or trypsin and was separated with 20 percent acetonitrile and 0.1 percent trifluoroacetic acid by reverse phase chromatography. The effect of this fraction (LycIV) on the post-potential amplitude was concentration-dependent, and was fitted with a quadratic hyperbola having a half maximal effect of 0.9 µg protein/ml. SDS-polyacrylamide gel electrophoresis of LycIV showed an enriched polypeptide band with apparent molecular weight of ~8 kDa. The observed effects were similar to those of toxins that inhibit sodium channel inactivation and different from the effects of potassium channel blockers. Pore formation or membrane disruption could be ruled out. It was concluded that the venom contains a neurotoxic polypeptide that alters the repolarization of action potentials, probably by inhibiting sodium channel inactivation

Loxoscelismo en Chile: estudios epidemiologicos, clínicos y experimentales / Loxoscelism in Chile: epidemiological, clinical and experimental studies

Se presenta un enfoque panorámico de estudios epidemiológicos, clínicos y experimentales referentes a Loxosceles laeta y loxocelismo efectuados en 1955-1988 en Santiago, Chile. Se estudiaron 216 casos de loxoscelismo. Los hechos más relevantes fueron: 52,8% correspondió a mujeres; edad entre 7 meses y 78 años; 84,3% fué loxoscelismo cutáneo (LC) y 15,7% loxoscelismo cutáneo-visceral (LCV); 73,6% sucedió en época calurosa; en 86,6% el accidente ocurrió en la vivienda, especialmente en dormitórios, mientras la persona dormía o se vestía. La araña fué vista en 60,2% de los casos e identificada en laboratório como L. laeta en 17,7% (10,6%) de los 216 casos). Los sitios más frecuentemente afectados fueron las extremidades con 67,6%, lancetazo urente fué el síntoma inicial más frecuente. Dolor, edema y placa livedoide, la cual posteriormente se transformaría en escara necrótica, fueron las manifestaciones locales predominantes. En LCV hematuria y hemoglobinuria fueron constantes, ictericia, fiebre y compromiso de conciencia se presentaron en la mayoría de los casos. Tratamiento: LC con antihistamínicos o corticoides inyectables, LCV con corticoides inyectables. La condición de los pacientes en el último control fué: curación completa en 75,5%, curación con secuela cicatrizal en 8,3%, muerte en 3,7% (todos con LCV) y abandono en 12,5%. Adicionalmente, se ha efectuado una serie de estudios experimentales, tanto in vivo como in vitro para esclarecer aspectos básicos sobre el veneno de L. laeta y el tratamiento del loxoscelismo

Loxoscelismo un problema de salud en el Perú / Loxoscelism: a health problem in Perú

In the major coastal cities on the western slopes of the Andes in Perú, the rate of intradomiciliary infestation by spiders of the genus Loxosceles is high. This poses an important public health problem, as this spider's poison has both local (cutaneous necrosis) and systemic (intravascular hemolysis, anemia, widespread intravascular coagulation, hemoglobinuria, and acute renal insuficiency) effects, which are often fatal. There is as yet no way to confirm a diagnosis of loxoscelism in the early poisoning stages, nor to predict what course the condition will take in a particular victim. Moreover, there is controversy over the efficacy of the various treatment schemes, which include antiloxoscelic serum, corticosteroids, antihistamines, urine alkalizers, early surgery, and local thermocoagulation. For these reasons, and given the multiplicity of clinical forms of loxoscelism, more studies should be carried out at centers and hospitals in several regions, in order to establish methods for early detection of the disease and a rational assessment of the various therapies. It is also necessary to devise, test and evaluate techniques for standardizing the potency of the commercial antidote using animal models

Aspectos epidemiológicos del loxoscelismo / Epidemiological aspects of loxoscelism

Se revisan los principales aspectos epidemiológicos del loxoscelismo en el Perú. Este araneismo, se tipifica como un accidente principalmente observado en las ciudades de la costa y sierra peruana, producido por picadura de las arañas loxosceles laeta y L. rufipes, y sin predominancia de ninguno de los sexos. Es un accidente de prestación más frecuente en los meses de verano, siendo fundamentalmente un accidente intradomiciliario, que ocurre en horas de la noche y primeras de la mañana. Se evalúan las casuísticas hospitalarias reportadas en el periodo 1943 a 1986, donde se reportan dos sindromes clínicos: cutáneos (74%) y sistémico (26%). La mortalidad se asocia al sindrome sistémico con la insuficiencia renal, siendo la letalidad mayor en pacientes menores de 13 años. Se propone la adopción de medidas de control y prevención de este envenenamiento

Acidentes por aranhas de interesse toxicológico / Accidents by spiders of toxicological interest

Procura-se de maneira objetiva fornecer informaçöes sobre reconhecimento e conduta frente ao acidente por araneídeos, destinando-se à orientaçäo de estudantes e profissionais de área de saúde