Neural control of redox response and microbiota-triggered inflammation in Drosophila gut.

Background: The neural system plays a critical role in controlling gut immunity, and the gut microbiota contributes to this process. However, the roles and mechanisms of gut-brain-microbiota interactions remain unclear. To address this issue, we employed Drosophila as a model organism. We have previously shown that NP3253 neurons, which are connected to the brain and gut, are essential for resistance to oral bacterial infections. Here, we aimed to investigate the role of NP3253 neurons in the regulation of gut immunity. Methods: We performed RNA-seq analysis of the adult Drosophila gut after genetically inactivating the NP3253 neurons. Flies were reared under oral bacterial infection and normal feeding conditions. In addition, we prepared samples under germ-free conditions to evaluate the role of the microbiota in gut gene expression. We knocked down the genes regulated by NP3253 neurons and examined their susceptibility to oral bacterial infections. Results: We found that immune-related gene expression was upregulated in NP3253 neuron-inactivated flies compared to the control. However, this upregulation was abolished in axenic flies, suggesting that the immune response was abnormally activated by the microbiota in NP3253 neuron-inactivated flies. In addition, redox-related gene expression was downregulated in NP3253 neuron-inactivated flies, and this downregulation was also observed in axenic flies. Certain redox-related genes were required for resistance to oral bacterial infections, suggesting that NP3253 neurons regulate the redox responses for gut immunity in a microbiota-independent manner. Conclusion: These results show that NP3253 neurons regulate the appropriate gene expression patterns in the gut and contribute to maintain homeostasis during oral infections.

Mathematical modelling for antimicrobial photodynamic therapy mediated by 5-aminolaevulinic acid: An in vitro study.

BACKGROUND: Antimicrobial photodynamic therapy (aPDT) using aminolaevulinic acid (ALA) is a promising alternative to antibiotic therapy. ALA administration induces protoporphyrin IX (PpIX) accumulation in bacteria, and light excitation of the accumulated PpIX generates singlet oxygen to bacterial toxicity. Several factors, including drug administration and light irradiation conditions, contribute to the antibiotic effect. Such multiple parameters should be determined moderately for effective aPDT in clinical practice. METHODS: A mathematical model to predict bacterial dynamics in ALA-aPDT following clinical conditions was constructed. Applying a pharmacokineticspharmacodynamics (PK-PD) approach, which is widely used in antimicrobial drug evaluation, viable bacteria count by defining the bactericidal rate as the concentration of singlet oxygen produced when PpIX in bacteria is irradiated by light. RESULTS: The in vitro experimental results of ALA-aPDT for Pseudomonas aeruginosa demonstrated the PK-PD model validity. The killing rate has an upper limit, and the lower power density for a long irradiation time can suppress the viable bacteria number when the light dosages are the same. CONCLUSIONS: This study proposed a model of bacterial viability change in ALA-aPDT based on the PK-PD model and confirmed, by in vitro experiments using PA, that the variation of bacterial viability with light-sensitive substance concentration and light irradiation power densities could be expressed. Further validation of the PK-PD model with other gram negative and gram positive strains will be needed.

Nodule formation in Bombyx mori larvae is regulated by BmToll10-3.

Nodule formation is a two-step cell-mediated immune response that is elicited by the cytokine spätzle1. Spätzle1 is activated within 30 s of invasion by microorganisms via an extracellular signaling pathway that consists of pathogen-associated molecular pattern recognition receptors, C-type lectins, and serine proteases. Here, we investigated a hemocyte molecule that is involved in eliciting the first step of nodule formation. BmToll10-3 was one of 14 Toll homologs identified in the silkworm Bombyx mori; it is an ortholog of Spodoptera exigua Toll. Previous research suggested that SeToll elicits nodule formation, but no evidence was presented to indicate whether SeToll elicited the first or second step of nodule formation. Reverse transcription-polymerase chain reaction and immunostaining confirmed that BmToll10-3 is expressed in granulocytes. To determine whether BmToll10-3 is involved in eliciting the first step of nodule formation, we tested an antiserum raised against BmToll10-3 in a nodule formation assay. The antiserum strongly inhibited the first step of nodule formation in B. mori larvae. Next, we tried to knock out BmToll10-3 using genome editing. Strains that were heterozygous for a truncated BmToll10-3 allele were generated, but no strain that was homozygous for truncated BmToll10-3 was generated. Nonetheless, several healthy homozygous larvae were identified before pupation, and we used these larvae in a nodule formation assay. The larvae that were homozygous for truncated BmToll10-3 did not form nodules. These results suggest that BmToll10-3 is involved in a cellular immunity, nodule formation.

2-Hydroxyindoline-3-triethylammonium Bromide: A Reagent for Formal C3-Electrophilic Reactions of Indoles.

A novel indole-2,3-epoxide equivalent, 2-hydroxyindoline-3-triethylammonium bromide, was found to be a convenient reagent for formal C3-electrophilic reactions of indoles with various nucleophiles. By taking advantage of the nucleophilic character of the oxygen of the 2-hydroxyindoline, the interrupted retro-Claisen and interrupted Feist-Bénary reactions with 1,3-dicarbonyl compounds were efficiently achieved.

Pressure-Induced Transition of Bilayers in a Nonionic Surfactant Solution.

Pressure effects on the bilayers of polyoxyethylene type nonionic surfactant in water have been investigated by means of small- and wide-angle X-ray scattering. It has been found that the Krafft transition from the micellar phase to the lamellar gel phase (Lß) is induced by pressure. By further pressurizing, the lamellar structural parameters, such as the repeat distance d and Caillé parameter η, discontinuously decrease after taking a maximum. All the SAXS and WAXS results revealed that the Lß phase is transformed into the higher-ordered lamellar crystal phase (Lc). On the basis of these observations, we have made the T-C and T-P phase diagrams.