Lethal and sublethal effects of essential oil of Lippia sidoides (Verbenaceae) and monoterpenes on Chagas' disease vector Rhodnius prolixus

Submitted by Sandra Infurna ([email protected]) on 2019-09-24T16:05:05Z No. of bitstreams: 1 PatriciaAzambuja_EloiSGarcia_etal_IOC_2017.pdf: 564407 bytes, checksum: baa6167272d6528479e860206d9a6a47 (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2019-09-24T16:11:34Z (GMT) No. of bitstreams: 1 PatriciaAzambuja_EloiSGarcia_etal_IOC_2017.pdf: 564407 bytes, checksum: baa6167272d6528479e860206d9a6a47 (MD5)Made available in DSpace on 2019-09-24T16:11:34Z (GMT). No. of bitstreams: 1 PatriciaAzambuja_EloiSGarcia_etal_IOC_2017.pdf: 564407 bytes, checksum: baa6167272d6528479e860206d9a6a47 (MD5) Previous issue date: 2017Universidade Federal Rural do Rio de Janeiro. Instituto de Ciências Exatas. Departamento de Química. Seropédica, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Bioquímica e Fisiologia de Insetos. Rio de Janeiro, RJ, Brasil.Universidade Estadual Vale do Acaraú. Centro de Ciências Exatas e Tecnologia. Sobral, CE, Brasil.Universidade Federal Rural do Rio de Janeiro. Instituto de Florestas. Departamento de Ciências Ambientais. Seropédica, RJ, Brasil.Universidade Federal Rural do Rio de Janeiro. Instituto de Ciências Exatas. Departamento de Química. Seropédica, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Bioquímica e Fisiologia de Insetos. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Bioquímica e Fisiologia de Insetos. Rio de Janeiro, RJ, Brasil.Universidade Federal Rural do Rio de Janeiro. Instituto de Ciências Exatas. Departamento de Química. Seropédica, RJ, Brasil.The aim of this study was to identify the composition of the essential oil from leaves of Lippia sidoides (EOLS), a typical shrub commonly found in the dry northeast of Brazil, popularly known as "alecrim-pimenta". Additionally, we investigated the nymphicidal, ovicidal, phagoinhibitory and excretion effects of EOLS, its major constituent thymol and its isomer carvacrol, on fourth instar nymphs and eggs of Rhodnius prolixus, the Chagas' disease vector. The nymphicidal and ovicidal activity of thymol, carvacrol, and EOLS was assessed by tests using impregnated Petri dishes. The lethal concentration values (LC50) for EOLS, carvacrol, and thymol were 54.48, 32.98, and 9.38 mg/cm2, respectively. The ovicidal test showed that both carvacrol and thymol (50 mg/cm2) inhibited hatching (50% and 23.3%, respectively), while treatments with 10 mg/cm2 or 50 mg/cm2 EOLS did not affect the hatching rate at all (80% and 90%, respectively). We observed an anti-feeding effect in insects fed with blood containing natural products at the higher concentrations (100 µg/mL). Finally, excretion rate was affected by EOLS and carvacrol, but not by thymol. These findings offer novel insights into basic physiological processes that make the tested natural compounds interesting candidates for new types of insecticides

Bacterial community composition shifts in the gut of Periplaneta americana fed on different lignocellulosic materials

ABSTRACT: Cockroaches are insects that can accommodate diets of different composition, including lignocellulosic materials. Digestion of these compounds is achieved by the insect’s own enzymes and also by enzymes produced by gut symbionts. The presence of different and modular bacterial phyla on the cockroach gut tract suggests that this insect could be an interesting model to study the organization of gut bacterial communities associated with the digestion of different lignocellulosic diets. Thus, changes in the diversity of gut associated bacterial communities of insects exposed to such diets could give useful insights on how to improve hemicellulose and cellulose breakdown systems. In this work, through sequence analysis of 16S rRNA clone libraries, we compared the phylogenetic diversity and composition of gut associated bacteria in the cockroach Periplaneta americana collected in the wild-types or kept on two different diets: sugarcane bagasse and crystalline cellulose. These high fiber diets favor the predominance of some bacterial phyla, such as Firmicutes, when compared to wild-types cockroaches. Our data show a high bacterial diversity in P. americana gut, with communities composed mostly by the phyla Bacteroidetes, Firmicutes, Proteobacteria and Synergistetes. Our data show that the composition and diversity of gut bacterial communities could be modulated by diet composition. The increased presence of Firmicutes in sugarcane bagasse and crystalline cellulose-fed animals suggests that these bacteria are strongly involved in lignocellulose digestion in cockroach guts. BACKGROUND: Cockroaches are omnivorous animals that can incorporate in their diets food of different composition, including lignocellulosic materials. Digestion of these compounds is achieved by the insect’s own enzymes and also by enzymes produced by gut symbiont. However, the influence of diet with different fiber contents on gut bacterial communities and how this affects the digestion of cockroaches is still unclear. The presence of some bacterial phyla on gut tract suggests that cockroaches could be an interesting model to study the organization of gut bacterial communities during digestion of different lignocellulosic diets. Knowledge about the changes in diversity of gut associated bacterial communities of insects exposed to such diets could give interesting insights on how to improve hemicellulose and cellulose breakdown systems. METHODOLOGY/PRINCIPAL FINDINGS: We compared the phylogenetic diversity and composition of gut associated bacteria in the cockroach P. americana caught on the wild or kept on two different diets: sugarcane bagasse and crystalline cellulose. For this purpose we constructed bacterial 16S rRNA gene libraries which showed that a diet rich in cellulose and sugarcane bagasse favors the predominance of some bacterial phyla, more remarkably Firmicutes, when compared to wild cockroaches. Rarefaction analysis, LIBSHUFF and UniFrac PCA comparisons showed that gene libraries of wild insects were the most diverse, followed by sugarcane bagasse fed and then cellulose fed animals. It is also noteworthy that cellulose and sugarcane bagasse gene libraries resemble each other. CONCLUSION/SIGNIFICANCE: Our data show a high bacterial diversity in P. americana gut, with communities composed mostly by the phyla Bacteroidetes, Firmicutes, Proteobacteria and Synergistetes. The composition and diversity of gut bacterial communities could be modulated by font of diet composition. The increased presence of Firmicutes in sugarcane bagasse and crystalline cellulose-fed animals suggests that these bacteria are strongly involved in lignocellulose digestion in cockroach guts

Blood leukocytes from benznidazole-treated indeterminate chagas disease patients display an overall type-1-modulated cytokine profile upon short-term in vitro stimulation with <it>trypanosoma cruzi</it> antigens

<p>Abstract</p> <p>Background</p> <p>Benznidazole (Bz)-chemotherapy is recommended to prevent Chagas disease progression, despite its limited efficacy during chronic disease. However, the host mechanisms underlying these benefits still remain to be elucidated.</p> <p>Methods</p> <p>In this study, we have used short-term whole blood cultures to describe the cytokine profile of Bz-treated Indeterminate Chagas disease patients-(INDt) as compared to untreated patients-(IND).</p> <p>Results</p> <p>Our findings showed that IND presented increased levels of IL-10⁺neutrophils, IL-12⁺ and IL-10⁺monocytes and IFN-γ⁺NK-cells. Moreover, IND showed slight increase of IL-4⁺CD4⁺T-cells and enhanced levels of IL-10⁺CD8⁺T-cells and B-cells. Additional analysis of cytokine Low and High producers also highlighted the presence of High cytokine producers within IND, including IL-10 from CD4+ T-cells and IFN-γ from CD8⁺ T-cells, as compared to NI. The Bz-treatment lead to an overall cytokine down-regulation in the innate and adaptive compartments, including low levels of IL-12⁺ and IL-10⁺neutrophils and monocytes, IFN-γ⁺NK-cells, IL-12⁺, TNF-α⁺, IFN-γ⁺ and IL-5⁺CD4⁺T-cells and IL-10⁺B-cells, along with basal levels of cytokine-expressing CD8⁺T-cells in INDt as compared to IND. The in vitro antigen stimulation shifted the cytokine profile toward a type 1-modulated profile, with increased levels of IL-12⁺ and IL-10⁺ monocytes, IFN-γ⁺ and IL-4⁺NK-cells along with TNF-α⁺ and IFN-γ⁺CD8⁺T-cells. Analysis of Low and High cytokine producers, upon in vitro antigen stimulation, further confirm these data.</p> <p>Conclusion</p> <p>Together, our findings showed that the Bz treatment of Indeterminate Chagas’ disease patients shifts the cytokine patterns of peripheral blood monocytes, NK-cells and CD8⁺ T-cells towards a long-lasting Type-1-modulated profile that could be important to the maintenance of a non-deleterious immunological microenvironment.</p

An insight into the transcriptome of the digestive tract of the bloodsucking bug, Rhodnius prolixus.

The bloodsucking hemipteran Rhodnius prolixus is a vector of Chagas' disease, which affects 7-8 million people today in Latin America. In contrast to other hematophagous insects, the triatomine gut is compartmentalized into three segments that perform different functions during blood digestion. Here we report analysis of transcriptomes for each of the segments using pyrosequencing technology. Comparison of transcript frequency in digestive libraries with a whole-body library was used to evaluate expression levels. All classes of digestive enzymes were highly expressed, with a predominance of cysteine and aspartic proteinases, the latter showing a significant expansion through gene duplication. Although no protein digestion is known to occur in the anterior midgut (AM), protease transcripts were found, suggesting secretion as pro-enzymes, being possibly activated in the posterior midgut (PM). As expected, genes related to cytoskeleton, protein synthesis apparatus, protein traffic, and secretion were abundantly transcribed. Despite the absence of a chitinous peritrophic membrane in hemipterans - which have instead a lipidic perimicrovillar membrane lining over midgut epithelia - several gut-specific peritrophin transcripts were found, suggesting that these proteins perform functions other than being a structural component of the peritrophic membrane. Among immunity-related transcripts, while lysozymes and lectins were the most highly expressed, several genes belonging to the Toll pathway - found at low levels in the gut of most insects - were identified, contrasting with a low abundance of transcripts from IMD and STAT pathways. Analysis of transcripts related to lipid metabolism indicates that lipids play multiple roles, being a major energy source, a substrate for perimicrovillar membrane formation, and a source for hydrocarbons possibly to produce the wax layer of the hindgut. Transcripts related to amino acid metabolism showed an unanticipated priority for degradation of tyrosine, phenylalanine, and tryptophan. Analysis of transcripts related to signaling pathways suggested a role for MAP kinases, GTPases, and LKBP1/AMP kinases related to control of cell shape and polarity, possibly in connection with regulation of cell survival, response of pathogens and nutrients. Together, our findings present a new view of the triatomine digestive apparatus and will help us understand trypanosome interaction and allow insights into hemipteran metabolic adaptations to a blood-based diet.Journal ArticleResearch Support, N.I.H. IntramuralResearch Support, Non-U.S. Gov'tSCOPUS: ar.jSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Bootstrapped phylogram of <i>Rhodnius prolixus</i> midgut lectins aligned with their best matches to the NR database.

<p>Bootstrap values above 50% are shown on the branches. The bottom line indicates 10% amino acid sequence divergence between the proteins. <i>R. prolixus</i> sequences are shown by the notation RP followed by a unique number. The remaining sequences were obtained from GenBank and are annotated with the first three letters of the genus name, followed by the first three letters of the species name, followed by their GenBank GI number. One thousand replicates were done for the bootstrap test using the neighbor joining test.</p