Highlights in the knowledge of brown spider toxins

Abstract Brown spiders are venomous arthropods that use their venom for predation and defense. In humans, bites of these animals provoke injuries including dermonecrosis with gravitational spread of lesions, hematological abnormalities and impaired renal function. The signs and symptoms observed following a brown spider bite are called loxoscelism. Brown spider venom is a complex mixture of toxins enriched in low molecular mass proteins (4-40 kDa). Characterization of the venom confirmed the presence of three highly expressed protein classes: phospholipases D, metalloproteases (astacins) and insecticidal peptides (knottins). Recently, toxins with low levels of expression have also been found in Loxosceles venom, such as serine proteases, protease inhibitors (serpins), hyaluronidases, allergen-like toxins and histamine-releasing factors. The toxin belonging to the phospholipase-D family (also known as the dermonecrotic toxin) is the most studied class of brown spider toxins. This class of toxins single-handedly can induce inflammatory response, dermonecrosis, hemolysis, thrombocytopenia and renal failure. The functional role of the hyaluronidase toxin as a spreading factor in loxoscelism has also been demonstrated. However, the biological characterization of other toxins remains unclear and the mechanism by which Loxosceles toxins exert their noxious effects is yet to be fully elucidated. The aim of this review is to provide an insight into brown spider venom toxins and toxicology, including a description of historical data already available in the literature. In this review article, the identification processes of novel Loxosceles toxins by molecular biology and proteomic approaches, their biological characterization and structural description based on x-ray crystallography and putative biotechnological uses are described along with the future perspectives in this field.(AU)

Highlights in the knowledge of brown spider toxins

Abstract Brown spiders are venomous arthropods that use their venom for predation and defense. In humans, bites of these animals provoke injuries including dermonecrosis with gravitational spread of lesions, hematological abnormalities and impaired renal function. The signs and symptoms observed following a brown spider bite are called loxoscelism. Brown spider venom is a complex mixture of toxins enriched in low molecular mass proteins (440 kDa). Characterization of the venom confirmed the presence of three highly expressed protein classes: phospholipases D, metalloproteases (astacins) and insecticidal peptides (knottins). Recently, toxins with low levels of expression have also been found in Loxosceles venom, such as serine proteases, protease inhibitors (serpins), hyaluronidases, allergen-like toxins and histamine-releasing factors. The toxin belonging to the phospholipase-D family (also known as the dermonecrotic toxin) is the most studied class of brown spider toxins. This class of toxins single-handedly can induce inflammatory response, dermonecrosis, hemolysis, thrombocytopenia and renal failure. The functional role of the hyaluronidase toxin as a spreading factor in loxoscelism has also been demonstrated. However, the biological characterization of other toxins remains unclear and the mechanism by which Loxosceles toxins exert their noxious effects is yet to be fully elucidated. The aim of this review is to provide an insight into brown spider venom toxins and toxicology, including a description of historical data already available in the literature. In this review article, the identification processes of novel Loxosceles toxins by molecular biology and proteomic approaches, their biological characterization and structural description based on x-ray crystallography and putative biotechnological uses are described along with the future perspectives in this field.

Análise do volume e de glicoproteínas presentes no fluido gengival como um indicador de inflamação gengival / Evaluation of the volume and glycoproteins in the crevicular gingival fluid as an indicator of gingival inflammation

O objetivo deste trabalho foi avaliar a quantidade de fluido gengival, bem como a presença de glicoproteínas em sítios com saúde (S), gengivite (G) e periodontite (P). O fluido foi coletado de seis pacientes apresentando três sítios para cada condição (S, G e P). Foram utilizadas tiras de papel (2x15mm), inseridas 1 mm abaixo da margem gengival por 30 s. Após 5 minutos da primeira coleta, realizou-se uma segunda coleta dos mesmos sítios. A primeira amostra foi aplicada solução de ninhidrina (0,2%) para determinar a quantidade de fluido absorvido em mm2. As amostras obtidas da segunda coleta foram analisadas com o teste ELISA. Os resultados mostraram que a quantidade (mm2) de fluido absorvido foi de 1,039±0,468, 1,780±0,930 e 1,778±0,881 respectivamente para os sítios com S, G e P. Segundo o teste ANOVA, as diferenças foram significativas (p=0,017) entre os sítios S versus G e P, não havendo diferenças entre estes dois últimos. Para as glicoproteínas, não foram observadas diferenças significativas em relação densidade óptica (DO) da vitronectina (S= 0,2747±0,095, G= 0,3528±0,092 e P= 0,3522±0,075), sendo p= 0,106, bem como para a fibronectina (S= 0,1831±0,108, G= 0,2757±0,137 e P= 0,2757±0,087), sendo p= 0,144. Considerando apenas sítios S e inflamados (G+P) observou-se diferenças significativas na presença das glicoproteínas (p<0,05 - Teste t). Conclui-se com estes resultados que a análise do volume de fluido gengival e das glicoproteínas estudadas, servem com um indicador de inflamação gengival, porém não foram capazes de fazer distinção entre os sítios com G e P.