红带锥蝽与朗氏锥虫的相互作用：免疫系统和微生物群数量的调节
Rhodnius prolixus interaction with Trypanosoma rangeli: modulation of the immune system and microbiota population.
作者信息
Vieira Cecilia S, Mattos Débora P, Waniek Peter J, Santangelo Jayme M, Figueiredo Marcela B, Gumiel Marcia, da Mota Fabio F, Castro Daniele P, Garcia Eloi S, Azambuja Patrícia
机构信息
Laboratório de Bioquímica e Fisiologia de Insetos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (IOC/FIOCRUZ), Rio de Janeiro, RJ, Brazil.
Departamento de Ciências Ambientais, Instituto de Florestas, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, RJ, Brazil.
出版信息
Parasit Vectors. 2015 Mar 1;8:135. doi: 10.1186/s13071-015-0736-2.
BACKGROUND
Trypanosoma rangeli is a protozoan that infects a variety of mammalian hosts, including humans. Its main insect vector is Rhodnius prolixus and is found in several Latin American countries. The R. prolixus vector competence depends on the T. rangeli strain and the molecular interactions, as well as the insect's immune responses in the gut and haemocoel. This work focuses on the modulation of the humoral immune responses of the midgut of R. prolixus infected with T. rangeli Macias strain, considering the influence of the parasite on the intestinal microbiota.
METHODS
The population density of T. rangeli Macias strain was analysed in different R. prolixus midgut compartments in long and short-term experiments. Cultivable and non-cultivable midgut bacteria were investigated by colony forming unit (CFU) assays and by 454 pyrosequencing of the 16S rRNA gene, respectively. The modulation of R. prolixus immune responses was studied by analysis of the antimicrobial activity in vitro against different bacteria using turbidimetric tests, the abundance of mRNAs encoding antimicrobial peptides (AMPs) defensin (DefA, DefB, DefC), prolixicin (Prol) and lysozymes (LysA, LysB) by RT-PCR and analysis of the phenoloxidase (PO) activity.
RESULTS
Our results showed that T. rangeli successfully colonized R. prolixus midgut altering the microbiota population and the immune responses as follows: 1 - reduced cultivable midgut bacteria; 2 - decreased the number of sequences of the Enterococcaceae but increased those of the Burkholderiaceae family; the families Nocardiaceae, Enterobacteriaceae and Mycobacteriaceae encountered in control and infected insects remained the same; 3 - enhanced midgut antibacterial activities against Serratia marcescens and Staphylococcus aureus; 4 - down-regulated LysB and Prol mRNA levels; altered DefB, DefC and LysA depending on the infection (short and long-term); 5 - decreased PO activity.
CONCLUSION
Our findings suggest that T. rangeli Macias strain modulates R. prolixus immune system and modifies the natural microbiota composition.
背景
克氏锥虫是一种可感染包括人类在内的多种哺乳动物宿主的原生动物。其主要昆虫传播媒介是长红猎蝽，在几个拉丁美洲国家均有发现。长红猎蝽的媒介能力取决于克氏锥虫菌株、分子相互作用以及昆虫肠道和血腔中的免疫反应。本研究聚焦于感染克氏锥虫马西亚斯菌株的长红猎蝽中肠体液免疫反应的调节，同时考虑寄生虫对肠道微生物群的影响。
方法
在长期和短期实验中，分析了克氏锥虫马西亚斯菌株在不同长红猎蝽中肠区室中的种群密度。分别通过菌落形成单位（CFU）测定和16S rRNA基因的454焦磷酸测序研究了可培养和不可培养的中肠细菌。通过比浊法分析体外对不同细菌的抗菌活性、通过RT-PCR分析编码抗菌肽（AMP）防御素（DefA、DefB、DefC）、亲长红菌素（Prol）和溶菌酶（LysA、LysB）的mRNA丰度以及分析酚氧化酶（PO）活性，研究长红猎蝽免疫反应的调节。
结果
我们的结果表明，克氏锥虫成功定殖于长红猎蝽中肠，如下改变了微生物种群和免疫反应：1 - 可培养的中肠细菌减少；2 - 肠球菌科序列数量减少，但伯克霍尔德菌科序列数量增加；对照昆虫和感染昆虫中发现的诺卡氏菌科、肠杆菌科和分枝杆菌科数量保持不变；3 - 增强了对粘质沙雷氏菌和金黄色葡萄球菌的中肠抗菌活性；4 - 下调LysB和Prol mRNA水平；根据感染情况（短期和长期）改变DefB、DefC和LysA；5 - 降低PO活性。
结论
我们的研究结果表明，克氏锥虫马西亚斯菌株调节长红猎蝽免疫系统并改变天然微生物群组成。
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