BACKGROUND: Leishmaniasis is a group of neglected vector-borne diseases transmitted by phlebotomine sand flies. Leishmania parasites must overcome various defenses in the sand fly midgut, including the insects's immune response. Insect immunity is regulated by the ecdysone hormone, which binds to its nuclear receptor (EcR) and activates the transcription of genes involved in insect immunity. However, the role of ecdysone in sand fly immunity has never been studied. Phlebotomus perniciosus is a natural vector of Leishmania infantum; here, we manipulated its neuroendocrine system using azadirachtin (Aza), a natural compound known to affect ecdysone synthesis. METHODS: Phlebotomus perniciosus larvae and adult females were fed on food containing either Aza alone or Aza plus ecdysone, and the effects on mortality and ecdysis were evaluated. Genes related to ecdysone signaling and immunity were identified in P. perniciosus, and the expression of antimicrobial peptides (AMPs), EcR, the ecdysone-induced genes Eip74EF and Eip75B, and the transcription factor serpent were analyzed using quantitative polymerase chain reaction (PCR). RESULTS: Aza treatment inhibited molting of first-instar (L1) larvae to L2, with only 10% of larvae molting compared to 95% in the control group. Serpent and Eip74EF, attacin, defensin 1, and defensin 2 genes were downregulated by Aza treatment in larvae. Similarly, Aza-treated adult females also presented suppression of ecdysone signaling-related genes and the AMPs attacin and defensin 2. Notably, all gene repression caused by Aza was reversed by adding ecdysone concomitantly with Aza to the larval or female food, indicating that these genes are effective markers for ecdysone repression. CONCLUSIONS: These results highlight the critical role of ecdysone in regulating the development and immunity of P. perniciosus, which potentially could interfere with Leishmania infection.

• Klíčová slova
• Phlebotomus perniciosus, Antimicrobial peptides, Azadirachtin, Ecdysone,
• MeSH
• antimikrobiální peptidy genetika   farmakologie   MeSH
• ekdyson * MeSH
• hmyz - vektory účinky léků   genetika   parazitologie   imunologie   MeSH
• hmyzí proteiny genetika   metabolismus   MeSH
• larva * účinky léků   imunologie   genetika   MeSH
• limoniny * farmakologie   MeSH
• Phlebotomus * účinky léků   genetika   parazitologie   imunologie   MeSH
• shazování tělního pokryvu účinky léků   MeSH
• signální transdukce * účinky léků   MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antimikrobiální peptidy MeSH
• azadirachtin MeSH Prohlížeč
• ekdyson * MeSH
• hmyzí proteiny MeSH
• limoniny * MeSH

We have examined the imprecision in the estimation of PCR efficiency by means of standard curves based on strategic experimental design with large number of technical replicates. In particular, how robust this estimation is in terms of a commonly varying factors: the instrument used, the number of technical replicates performed and the effect of the volume transferred throughout the dilution series. We used six different qPCR instruments, we performed 1-16 qPCR replicates per concentration and we tested 2-10 μl volume of analyte transferred, respectively. We find that the estimated PCR efficiency varies significantly across different instruments. Using a Monte Carlo approach, we find the uncertainty in the PCR efficiency estimation may be as large as 42.5% (95% CI) if standard curve with only one qPCR replicate is used in 16 different plates. Based on our investigation we propose recommendations for the precise estimation of PCR efficiency: (1) one robust standard curve with at least 3-4 qPCR replicates at each concentration shall be generated, (2) the efficiency is instrument dependent, but reproducibly stable on one platform, and (3) using a larger volume when constructing serial dilution series reduces sampling error and enables calibration across a wider dynamic range.

• Klíčová slova
• ANCOVA, analysis of covariance, Amplification efficiency, CLSI, Clinical and Laboratory Standards Institute, Cq, cycle of quantification, Dilution series, E, PCR efficiency, EPA, Environmental protection agency, FDA, food and Drug Administration, GMO, genetically modified organism, IEC, International Electrotechnical Commission, ISO, International Organization for Standardization, MIQE, minimum information for publication of quantitative real-time PCR experiments, NTC, no template control, RIN, RNA Integrity Number, RT-qPCR, reverse transcription-quantitative polymerase chain reaction, Real-time quantitative PCR, Standard curve, qPCR, qPCR assay validation,
• Publikační typ
• časopisecké články MeSH

BACKGROUND: RNA interference (RNAi) is a powerful approach to study a gene function. Transgenic RNAi is an adaptation of this approach where suppression of a specific gene is achieved by expression of an RNA hairpin from a transgene. In somatic cells, where a long double-stranded RNA (dsRNA) longer than 30 base-pairs can induce a sequence-independent interferon response, short hairpin RNA (shRNA) expression is used to induce RNAi. In contrast, transgenic RNAi in the oocyte routinely employs a long RNA hairpin. Transgenic RNAi based on long hairpin RNA, although robust and successful, is restricted to a few cell types, where long double-stranded RNA does not induce sequence-independent responses. Transgenic RNAi in mouse oocytes based on a shRNA offers several potential advantages, including simple cloning of the transgenic vector and an ability to use the same targeting construct in any cell type. RESULTS: Here we report our experience with shRNA-based transgenic RNAi in mouse oocytes. Despite optimal starting conditions for this experiment, we experienced several setbacks, which outweigh potential benefits of the shRNA system. First, obtaining an efficient shRNA is potentially a time-consuming and expensive task. Second, we observed that our transgene, which was based on a common commercial vector, was readily silenced in transgenic animals. CONCLUSIONS: We conclude that, the long RNA hairpin-based RNAi is more reliable and cost-effective and we recommend it as a method-of-choice when a gene is studied selectively in the oocyte.

• MeSH
• genetické vektory genetika   MeSH
• genový knockdown ekonomika   metody   MeSH
• HeLa buňky MeSH
• klonování DNA MeSH
• křížení genetické MeSH
• lidé MeSH
• malá interferující RNA metabolismus   MeSH
• myši transgenní MeSH
• myši MeSH
• oocyty metabolismus   MeSH
• plazmidy genetika   MeSH
• polymerázová řetězová reakce MeSH
• protoonkogenní proteiny c-mos genetika   metabolismus   MeSH
• RNA interference * MeSH
• transgeny genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• malá interferující RNA MeSH
• protoonkogenní proteiny c-mos MeSH