Clonagem e expressão do gene bioinseticida TX4(6-1) em sistema heterologo.

bitstream/CNPMS/16145/1/Com_64.pd

Heterologous expression of an insecticidal gene from the armed spider (Phoneutria nigriventer)

Insect-pests are global problems that cause severe damage to crop plants, and their control is commonly based on chemical insecticides. However, negative effects of pesticides on the environment and human health emphasize the necessity to develop alternative methods for insect-pest control. In the present study, a gene coding for the insecticidal peptide TX4(6-1) of the Brazilian armed spider (Phoneutria nigriventer) was cloned in fusion with maltose binding protein (MBP) and expressed in Escherichia coli. The affinity purified protein MBP-GlyTX4 was cleaved with the Xa factor and used for a bioassay against Spodoptera frugiperda and rabbit immunization. Five micrograms GlyTX4 protein injected into the hemocoel of larvae and abdominal cavity of adults produced trembling and uncoordinated movements immediately after injection and all adult insects died after 12h. After two days, larvae became paralyzed and the epidermal color changed to dark brown. Furthermore, the development stage was prolonged for two weeks. Alternatively, slices of maize leaves were imbibed with 15 micrograms of the recombinant protein cleaved with the Xa factor and used as diet for larvae. In this experiment, all larvae died in about 30 minutes. Polyclonal antibodies anti-MBP-GlyTX4 were effective for recognizing MBP and GlyTX4 in whole cell extract from E. coli expressing the recombinant protein

Expression Of Vegf And Flk-1 And Flt-1 Receptors During Blood-brain Barrier (bbb) Impairment Following Phoneutria Nigriventer Spider Venom Exposure

Apart from its angiogenic and vascular permeation activity, the vascular endothelial growth factor (VEGF) has been also reported as a potent neuronal protector. Newborn rats with low VEGF levels develop neuron degeneration, while high levels induce protective mechanisms in several neuropathological conditions. Phoneutria nigriventer spider venom (PNV) disrupts the blood-brain barrier (BBB) and causes neuroinflammation in central neurons along with excitotoxic signals in rats and humans. All these changes are transient. Herein, we examined the expression of VEGF and its receptors, Flt-1 and Flk-1 in the hippocampal neurons following envenomation by PNV. Adult and neonatal rats were evaluated at time limits of 2, 5 and 24 h. Additionally, BBB integrity was assessed by measuring the expression of occludin, β-catenin and laminin and neuron viability was evaluated by NeuN expression. VEGF, Flt-1 and Flk-1 levels increased in PNV-administered rats, concurrently with respective mRNAs. Flt-1 and Flk-1 immunolabeling was nuclear in neurons of hippocampal regions, instead of the VEGF membrane-bound typical location. These changes occurred simultaneously with the transient decreases in BBB-associated proteins and NeuN positivity. Adult rats showed more prominent expressional increases of the VEGF/Flt-1/Flk-1 system and earlier recovery of BBB-related proteins than neonates. We conclude that the reactive expressional changes seen here suggest that VEGF and receptors could have a role in the excitotoxic mechanism of PNV and that such role would be less efficient in neonate rats. © 2013 by the authors; licensee MDPI, Basel, Switzerland.51225722588Vassilevsky, A.A., Koslov, S.A., Egorov, T.A., Grishin, E.V., Purification and characterization of biologically active peptides from spider venoms (2010) Methods Mol. 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Expressed sequence tags in venomous tissue of Scorpaena plumieri (Scorpaeniformes: Scorpaenidae)

Species of the family Scorpaenidae are responsible for accidents and sporadic casualties by the shore they inhabit. The species Scorpaena plumieri from this family populate the Northeastern and Eastern coast of Brazil causing human envenomation characterized by local and systemic symptoms. In experimental animals the venom induces cardiotoxic, hypotensive, and airway respiratory effects. As first step to identify the venom components we isolated gland mRNA to produce a cDNA library from the fish gland. This report describes the partial sequencing of 356 gland transcripts from S. plumieri. BLAST analysis of transcripts showed that 30% were unknown sequences, 17% hypothetical proteins, 17% related to metabolic enzymes, 14% belonged to signal transducing functions and the remaining groups (7-8%) composed by gene related with expressing proteins, regulatory proteins and structural proteins. A considerable number of these EST were not found in available databases suggesting the existence of new proteins and/or functions yet to be discovered. By screening the library with antibodies against a lectin fraction from S. plumieri venom we identified several clones whose DNA sequence showed similarities with lectins found in fish. In silico analysis of these clones confirm the identity of these molecules in the venom gland of S. plumieri. Espécies da família Scorpaenidae são responsáveis por acidentes e mortes esporádicas ao longo da costa que habitam. A espécie Scorpaena plumieri desta família povoam a costa Leste e Nordeste do Brasil, causando envenenamento humano caracterizado por sintomas locais e sistêmicos. Em modelos experimentais animais a peçonha induz cardiotoxicidade, efeitos hipotensivos e alterações nas vias aéreas respiratórias. Como primeiro passo para identificar os componentes da peçonha foram isolados os mRNA das glândulas do peixe para produzir uma biblioteca de cDNAs. Esse artigo descreve o sequenciamento parcial de 356 transcritos das glândulas de S. plumieri. Análises em bancos de dados (BLAST) dos transcritos demonstraram que 30% eram sequências desconhecidas, 17% proteínas hipotéticas, 17% relacionadas às enzimas do metabolismo, 14% pertenciam a funções de transdução de sinais e os demais grupos (7-8%) formados por genes relacionados com a expressão de proteínas, proteínas regulatórias e estruturais. Um número considerável destes EST não foi encontrado em bases de dados disponíveis, sugerindo a existência de novas proteínas e/ou funções ainda a serem descobertas. Ao fazer um barrido da biblioteca com anticorpos produzidos contra uma fração das lectinas do veneno de S. plumieri, identificamos vários clones, cuja sequência de DNA mostram semelhanças com lectinas encontradas em peixes. A análise in silico destes clones confirmam a identidade destas moléculas na glândula de peçonha de S. plumieri

Histopathological characterization of experimentally induced cutaneous loxoscelism in rabbits inoculated with Loxosceles similis venom

Envenomation by Loxosceles bites is characterized by dermonecrotic and/or systemic features that lead to several clinical signs and symptoms called loxoscelism. Dermonecrotic lesions are preceded by thrombosis of the dermal plexus. Recent studies show that atheromatous plaque is prone to thrombosis due to endothelial cell apoptosis. To the best of our knowledge, there are no reports of microscopic dermal lesion and endothelial cell apoptosis induced by Loxosceles similis venom in the literature. Thus, the aim of the present study is to describe histological lesions induced by L. similis venom in rabbit skin and to elucidate whether apoptosis of endothelial cells is involved in the pathogenesis of loxoscelism. Forty male rabbits were split into two groups: the control group (intradermally injected with 50 µL of PBS) and the experimental group (intradermally injected with 0.5 µg of L. similis crude venom diluted in 50 µL of PBS). After 2, 4, 6 and 8 hours of injection, skin fragments were collected and processed for paraffin or methacrylate embedding. Sections of 5 µm thick were stained by HE, PAS or submitted to TUNEL reaction. Microscopically, severe edema, diffuse heterophilic inflammatory infiltrate, perivascular heterophilic infiltrate, thrombosis, fibrinoid necrosis of arteriolar wall and cutaneous muscle necrosis were observed. Two hours after venom injection, endothelial cells with apoptosis morphology were evidenced in the dermal plexus. Apoptosis was confirmed by TUNEL reaction. It seems that endothelial cell apoptosis and its consequent desquamation is an important factor that induces thrombosis and culminates in dermonecrosis, which is characteristic of cutaneous loxoscelism

Successful xenogeneic germ cell transplantation from Jundia catfish (Rhamdia quelen) into adult Nile tilapia (Oreochromis niloticus) testes

Fish germ cell transplantation presents several important potential applications for aquaculture, including the preservation of germplasm from endangered fish species with high genetic and commercial values. Using this technique in studies developed in our laboratory with adult male Nile tilapias (Oreochromis niloticus), all the necessary procedures were successfully established, allowing the production of functional sperm and healthy progeny approximately 2 months after allogeneic transplantation. In the present study, we evaluated the viability of the adult Nile tilapia testis to generate sperm after xenogeneic transplant of germ cells from sexually mature Jundia catfish (Rhamdia quelen) that belong to a different taxonomic order. Therefore, in order to investigate at different time-periods post-transplantation, the presence and development of donor PKH26 labeled catfish germ cells were followed in the tilapia seminiferous tubules. From 7 to 20 days post-transplantation, only PKH26 labeled spermatogonia were observed, whereas spermatocytes at different stages of development were found at 70 days. Germ cell transplantation success and progression of spermatogenesis were indicated by the presence of labeled PKH26 spermatids and sperm on days 90 and 120 post-transplantation, respectively. Confirming the presence of the catfish genetic material in the tilapia testis, all recipient tilapias evaluated (n = 8) showed the genetic markers evaluated. Therefore, we demonstrated for the first time that the adult Nile tilapia testis offers the functional conditions for development of spermatogenesis with sperm production from a fish species belonging to a different order, which provides an important new venue for aquaculture advancement. © 2016 Elsevier Inc