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)

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

Abstract 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.

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.(AU)

Brazilian Theraphosidae: a toxicological point of view

Abstract 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.

Characterization of the first two toxins isolated from the venom of the ancient scorpion Tityus (Archaeotityus) mattogrossensis (Borelli, 1901)

Abstract Background: Almost all Tityus characterized toxins are from subgenera Atreus and Tityus, there are only a few data about toxins produced by Archaeotityus, an ancient group in Tityus genus. Methods: Tityus (Archaeotityus) mattogrossensis crude venom was fractionated by high performance liquid chromatography, the major fractions were tested in a frog sciatic nerve single sucrose-gap technique. Two fractions (Tm1 and Tm2) were isolated, partially sequenced by MALDI-TOF/MS and electrophysiological assayed on HEK293 Nav 1.3, HEK293 Nav 1.6, DUM and DRG cells. Results: The sucrose-gap technique showed neurotoxicity in four fractions. One fraction caused a delay of action potential repolarization and other three caused a reduction in amplitude. An electrophysiological assay showed that Tm1 is active on HEK293 Nav 1.3, HEK293 Nav 1.6, DUM and DRG cells, and Tm2 on HEK293 Nav 1.3 and DRG cells, but not in HEK293 Nav 1.6. In addition, Tm1 and Tm2 did promote a shift to more negative potentials strongly suggesting that both are -NaScTx. Conclusion: Although Tityus (Archaeotityus) mattogrossensis is considered an ancient group in Tityus genus, the primary structure of Tm1 and Tm2 is more related to Tityus subgenus. The patch clamp electrophysiological tests suggest that Tm1 and Tm2 are NaScTx, and also promoted no shift to more negative potentials, strongly suggesting that both are -NaScTx. This paper aimed to explore and characterize for the first time toxins from the ancient scorpion Tityus (Archaeotityus) mattogrossensis.

Toxicity and genotoxicity in Astyanax bimaculatus (Characidae) induced by microcystins from a bloom of Microcystis spp

Studies of genotoxicity in fish caused by cyanobacterial microcystins can be useful both in determining the sensitivity of native species, as well as comparing exposure routes. The genotoxicity caused by the microcystins LR and LA from a bloom collected in a eutrophic lake, was revealed in the fish Astyanax bimaculatus, a native species from South America. LC50 (72 h) was determined as 242.81 µg L-1 and LD50 (72 h) as 49.19 µg kg-1 bw. There was a significant increase of DNA damage in peripheral erythrocytes, following intraperitoneal injection (ip) with tested concentrations of 24.58 µg kg-1 bw and 36.88 µg kg-1 bw, as well as through body exposure to a concentration of 103.72 µg L-1. Micronucleus (MN) induction was observed after ip injections of 24.58 µg kg-1 bw and 36.88 µg kg-1 bw for 72 h, as well as following body exposure for 72 at 103.72 µg L-1. Thus, both exposure routes resulted in MN induction and DNA damage. Apoptosis-necrosis testing was carried out only by ip injection with concentrations of 24.58 µg -1 bw and 36.88 µg kg-1 bw. Exposure to microcystins at lower concentrations induced more apoptosis than necrosis in peripheral erythrocytes, whereas exposure at higher concentrations gave rise to both conditions. Thus, Astyanax bimaculatus can be considered as a species sensitive to the genotoxic effects caused by microcystins.