34
views
0
recommends
+1 Recommend
1 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Highlights in the knowledge of brown spider toxins

      review-article

      Read this article at

      ScienceOpenPublisherPMC
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          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.

          Related collections

          Most cited references148

          • Record: found
          • Abstract: found
          • Article: not found

          Brown spiders and loxoscelism.

          Accidents caused by brown spiders (Loxosceles genus) are classically associated with dermonecrotic lesions and systemic manifestations including intravascular haemolysis, disseminated intravascular coagulation and acute renal failure. Systemic reactions occur in a minority of cases, but may be severe in some patients and occasionally fatal. The mechanisms by which Loxosceles venom exerts these noxious effects are currently under investigation. The venom contains several toxins, some of which have been well-characterised biochemically and biologically. The purpose of the present review is to describe some insights into loxoscelism obtained over the last ten years. The biology and epidemiology of the brown spider, the histopathology of envenomation and the immunogenicity of Loxosceles venom are reviewed, as are the clinical features, diagnosis and therapy of brown spider bites. The identification and characterisation of some toxins and the mechanism of induction of local and systemic lesions caused by brown spider venom are also discussed. Finally, the biotechnological application of some venom toxins are covered.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Bacterial Sphingomyelinases and Phospholipases as Virulence Factors.

            Bacterial sphingomyelinases and phospholipases are a heterogeneous group of esterases which are usually surface associated or secreted by a wide variety of Gram-positive and Gram-negative bacteria. These enzymes hydrolyze sphingomyelin and glycerophospholipids, respectively, generating products identical to the ones produced by eukaryotic enzymes which play crucial roles in distinct physiological processes, including membrane dynamics, cellular signaling, migration, growth, and death. Several bacterial sphingomyelinases and phospholipases are essential for virulence of extracellular, facultative, or obligate intracellular pathogens, as these enzymes contribute to phagosomal escape or phagosomal maturation avoidance, favoring tissue colonization, infection establishment and progression, or immune response evasion. This work presents a classification proposal for bacterial sphingomyelinases and phospholipases that considers not only their enzymatic activities but also their structural aspects. An overview of the main physiopathological activities is provided for each enzyme type, as are examples in which inactivation of a sphingomyelinase- or a phospholipase-encoding gene impairs the virulence of a pathogen. The identification of sphingomyelinases and phospholipases important for bacterial pathogenesis and the development of inhibitors for these enzymes could generate candidate vaccines and therapeutic agents, which will diminish the impacts of the associated human and animal diseases.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: found
              Is Open Access

              Epidemiology of envenomations by terrestrial venomous animals in Brazil based on case reporting: from obvious facts to contingencies

              Background Envenomation remains a neglected public health issue in most tropical countries. A better understanding of the epidemiology of bites and stings by venomous animals should facilitate their prevention and management. This study aimed to explore the benefits that could be derived from the compulsory notification of cases as it is now routinely practiced in Brazil. Methods The Brazilian Notifiable Diseases Information System (SINAN) was consulted online for the 2001–2012 period on all envenomations by venomous terrestrial animals. We studied the incidence, severity, number of deaths, gender, season of accident and time between the accident and hospital consultation. Results In total, 1,192,667 accidents and 2,664 deaths from terrestrial venomous animals (snakes, scorpions, spiders, bees and caterpillars) were reported in Brazil during these 12 years, the circumstances of which are detailed in this study. Most envenomations and deaths were caused by snakebites and scorpion stings. However, incidence and mortality showed high regional variations. During this period, the steady and parallel increase of the cases from all the species resulted from several factors including the human population increase, gradual improvement of data collection system and, probably, environmental and socioeconomic factors affecting in a different way the incidence of envenomation by each zoological group and by region. Conclusion Mandatory reporting of cases appears to be a useful tool to improve the management of envenomations. However, local studies should be continued to account for the variability of accident circumstances and refine measures necessary for their management.
                Bookmark

                Author and article information

                Contributors
                dani_chaves@ufpr.br
                senffribeiro@ufpr.br
                anacarolina.wille@yahoo.com.br
                luiza_hg@yahoo.com.br
                olgachaim@ufpr.br
                +55 41 3266 2042 , veigass@ufpr.br
                Journal
                J Venom Anim Toxins Incl Trop Dis
                J Venom Anim Toxins Incl Trop Dis
                The Journal of Venomous Animals and Toxins Including Tropical Diseases
                BioMed Central (London )
                1678-9199
                8 February 2017
                8 February 2017
                2017
                : 23
                : 6
                Affiliations
                [1 ]ISNI 0000 0001 1941 472X, GRID grid.20736.30, , Department of Cell Biology, Federal University of Paraná (UFPR), ; Curitiba, PR Brazil
                [2 ]ISNI 0000 0001 2218 3838, GRID grid.412323.5, , Department of Structural and Molecular Biology, State University of Ponta Grossa (UEPG), ; Ponta Grossa, PR Brazil
                Article
                97
                10.1186/s40409-017-0097-8
                5299669
                28194160
                c0b6f0e6-2cad-4086-9ccd-089d107e0cb9
                © The Author(s). 2017

                Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License ( http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver ( http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

                History
                : 8 August 2016
                : 24 January 2017
                Funding
                Funded by: FundRef http://dx.doi.org/10.13039/501100002322, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior;
                Funded by: FundRef http://dx.doi.org/10.13039/501100003593, Conselho Nacional de Desenvolvimento Científico e Tecnológico;
                Funded by: FundRef http://dx.doi.org/10.13039/501100004612, Fundação Araucária;
                Categories
                Review
                Custom metadata
                © The Author(s) 2017

                brown spider,loxosceles,venom,toxins,loxoscelism,phospholipase-d,metalloprotease,insecticidal peptides,serineprotease,hyaluronidase

                Comments

                Comment on this article