An insight into the salivary gland and fat body transcriptome of Panstrongylus lignarius (Hemiptera: Heteroptera), the main vector of Chagas disease in Peru.

Triatomines are hematophagous arthropod vectors of Trypanosoma cruzi, the causative agent of Chagas Disease. Panstrongylus lignarius, also known as Panstrongylus herreri, is considered one of the most versatile triatomines because it can parasitize different hosts, it is found in different habitats and countries, it has sylvatic, peridomestic and domestic behavior and it is a very important vector of Chagas disease, especially in Peru. Molecules produced and secreted by salivary glands and fat body are considered of important adaptational value for triatomines because, among other functions, they subvert the host haemostatic, inflammatory and immune systems and detoxify or protect them against environmental aggressors. In this context, the elucidation of the molecules produced by these tissues is highly valuable to understanding the ability of this species to adapt and transmit pathogens. Here, we use high-throughput sequencing techniques to assemble and describe the coding sequences resulting from the transcriptome of the fat body and salivary glands of P. lignarius. The final assembly of both transcriptomes together resulted in a total of 11,507 coding sequences (CDS), which were mapped from a total of 164,676,091 reads. The CDS were subdivided according to their 10 folds overexpression on salivary glands (513 CDS) or fat body (2073 CDS). Among the families of proteins found in the salivary glands, lipocalins were the most abundant. Other ubiquitous families of proteins present in other sialomes were also present in P. lignarius, including serine protease inhibitors, apyrase and antigen-5. The unique transcriptome of fat body showed proteins related to the metabolic function of this organ. Remarkably, nearly 20% of all reads mapped to transcripts coded by Triatoma virus. The data presented in this study improve the understanding on triatomines' salivary glands and fat body function and reveal important molecules used in the interplay between vectors and vertebrate hosts.

Molecular technique for detection and identification of Helicobacter pylori in clinical specimens: a comparison with the classical diagnostic method / Técnica molecular para detecção e identificação de Helicobacter pylori em espécimes clínicas: comparação com o método clássico de diagnóstico

ABSTRACT Introduction: Helicobacter pylori is a bacterium found in human epithelial cells of the gastrointestinal tract. Its infection is related to different diseases, such as chronic gastritis, peptic ulcers, gastric lymphoma and adenocarcinoma. The infection by H. pylori is present in more than a half of the world population. Objectives: To detect H. pylori and to compare the diagnostic methods of the rapid urease test (RUT) and polymerase chain reaction (PCR). Materials and methods: The study was conducted between April and July, 2015. For such, three biopsies were collected from each patient. Two were used for PCR and one for RUT. Results: A total of 85 samples were collected from patients undergoing endoscopy, with 56 (65.88%) females and 29 (34.11%) males. From the total samples subjected to RUT, 15 (17.64%) were positive and 70 (82.35%), negative. In PCR for detection of gene 16S ribosomal ribonucleic acid (rRNA) of H. pylori, 66 (77.64%) presented positive results and 19 (22.35%), negative results. For the analysis of the presence of UreA gene in all samples, positive results were found in 70 (82.35%), and negative in 15 (17.64%). According to the results, RUT and the molecular test presented statistical difference. Conclusion: PCR is a useful method in the laboratorial routine to detect the presence of H. pylori in the stomach tissue, due to high sensitivity and specificity, but it requires a more careful analysis and standardization.

RESUMO Introdução: Helicobacter pylori é uma bactéria encontrada nas células epiteliais do trato gastrointestinal humano. Sua infecção relaciona-se com diferentes patologias, como gastrite crônica, úlcera péptica, linfoma gástrico e adenocarcinoma. A infecção por Helicobacter pylori está presente em mais da metade da população mundial. Objetivos: Detectar a presença de H. pylori e comparar os métodos diagnósticos do teste rápido de urease (TRU) e reação em cadeia da polimerase (PCR). Materiais e métodos: No estudo, realizado entre abril e julho de 2015, três biópsias foram coletadas de cada paciente. Duas foram usadas para realizar PCR e uma, para TRU. Resultados: Oitenta e cinco amostras foram coletadas dos pacientes por meio de endoscopia, sendo 56 (65,88%) mulheres e 29 (34,11%) homens. Do total dos indivíduos sujeitos ao TRU, 15 (17,64%) foram positivos e 70 (82,35%), negativos. Na PCR, na detecção do gene 16S ácido ribonucleico ribossômico (rRNA) de H. pylori, 66 (77,64%) apresentaram resultados positivos e 19 (22,35%), negativos. Para a análise da presença do gene UreA em todas as amostras, resultados positivos foram encontrados em 70 (82,35%) e negativos em 15 (17,64%). De acordo com os resultados, o TRU e o teste molecular apresentaram diferenças estatísticas. Conclusão: A PCR é um método útil na rotina laboratorial para detectar H. pylori em tecido de estômago devido à sua alta sensibilidade e especificidade, mas é necessária maior atenção na análise e na padronização.