Toxicity,behavior impairment,and repellence of essential oils from pepper‐rosmarin and patchouli to termites

Plant essential oils are potential sources of insecticidal compounds, but have rarely been explored for their effect on termites. In the present study, we assessed the chemical composition of essential oils of Lippia sidoides Cham. (pepper‐rosmarin; Verbenaceae) and Pogostemon cablin (Blanco) Benth. (patchouli; Lamiacaeae) and evaluated their toxicity, behavioral impairment, and repellence to termite species of the genera Amitermes and Microcerotermes (Isoptera: Termitidae: Termitinae). The main components of essential oils of L. sidoides and P. cablin were thymol (44.6%) and patchouli alcohol (36.6%), respectively. The essential oil of P. cablin was most potent against Amitermes cf. amifer Silvestri and had the lowest LD₅₀ (0.63 μg mg^?1). There was no difference in toxicity for Microcerotermes indistinctus Mathews between the essential oils of L. sidoides (LD₅₀ = 1.49 μg mg^?1) and P. cablin (LD₅₀ = 1.67 μg mg^?1). Pogostemon cablin essential oil was the most toxic to M. indistinctus (LC₅₀ = 0.32 μl ml^?1) and A. cf. amifer (LC₅₀ = 0.29 μl ml^?1). The essential oils analyzed exhibited high toxicity and repellence to the termites, in addition to reducing behavioral interactions among individuals, thus constituting potential termiticides.     

RUN and FYVE domain–containing protein 4 enhances autophagy and lysosome tethering in response to Interleukin-4

Autophagy is a key degradative pathway coordinated by external cues, including starvation, oxidative stress, or pathogen detection. Rare are the molecules known to contribute mechanistically to the regulation of autophagy and expressed specifically in particular environmental contexts or in distinct cell types. Here, we unravel the role of RUN and FYVE domain–containing protein 4 (RUFY4) as a positive molecular regulator of macroautophagy in primary dendritic cells (DCs). We show that exposure to interleukin-4 (IL-4) during DC differentiation enhances autophagy flux through mTORC1 regulation and RUFY4 induction, which in turn actively promote LC3 degradation, Syntaxin 17–positive autophagosome formation, and lysosome tethering. Enhanced autophagy boosts endogenous antigen presentation by MHC II and allows host control of Brucella abortus replication in IL-4–treated DCs and in RUFY4-expressing cells. RUFY4 is therefore the first molecule characterized to date that promotes autophagy and influences endosome dynamics in a subset of immune cells.     

Demonstration of Lignin-to-Peroxidase Direct Electron Transfer: A TRANSIENT-STATE KINETICS,DIRECTED MUTAGENESIS,EPR, AND NMR STUDY*

Versatile peroxidase (VP) is a high redox-potential peroxidase of biotechnological interest that is able to oxidize phenolic and non-phenolic aromatics, Mn²⁺, and different dyes. The ability of VP from Pleurotus eryngii to oxidize water-soluble lignins (softwood and hardwood lignosulfonates) is demonstrated here by a combination of directed mutagenesis and spectroscopic techniques, among others. In addition, direct electron transfer between the peroxidase and the lignin macromolecule was kinetically characterized using stopped-flow spectrophotometry. VP variants were used to show that this reaction strongly depends on the presence of a solvent-exposed tryptophan residue (Trp-164). Moreover, the tryptophanyl radical detected by EPR spectroscopy of H₂O₂-activated VP (being absent from the W164S variant) was identified as catalytically active because it was reduced during lignosulfonate oxidation, resulting in the appearance of a lignin radical. The decrease of lignin fluorescence (excitation at 355 nm/emission at 400 nm) during VP treatment under steady-state conditions was accompanied by a decrease of the lignin (aromatic nuclei and side chains) signals in one-dimensional and two-dimensional NMR spectra, confirming the ligninolytic capabilities of the enzyme. Simultaneously, size-exclusion chromatography showed an increase of the molecular mass of the modified residual lignin, especially for the (low molecular mass) hardwood lignosulfonate, revealing that the oxidation products tend to recondense during the VP treatment. Finally, mutagenesis of selected residues neighboring Trp-164 resulted in improved apparent second-order rate constants for lignosulfonate reactions, revealing that changes in its protein environment (modifying the net negative charge and/or substrate accessibility/binding) can modulate the reactivity of the catalytic tryptophan.