Cholesterol-binding motifs in STING that control endoplasmic reticulum retention mediate anti-tumoral activity of cholesterol-lowering compounds

The cGAS-STING pathway plays a crucial role in anti-tumoral responses by activating inflammation and reprogramming the tumour microenvironment. Upon activation, STING traffics from the endoplasmic reticulum (ER) to Golgi, allowing signalling complex assembly and induction of interferon and inflammatory cytokines. Here we report that cGAMP stimulation leads to a transient decline in ER cholesterol levels, mediated by Sterol O-Acyltransferase 1-dependent cholesterol esterification. This facilitates ER membrane curvature and STING trafficking to Golgi. Notably, we identify two cholesterol-binding motifs in STING and confirm their contribution to ER-retention of STING. Consequently, depletion of intracellular cholesterol levels enhances STING pathway activation upon cGAMP stimulation. In a preclinical tumour model, intratumorally administered cholesterol depletion therapy potentiated STING-dependent anti-tumoral responses, which, in combination with anti-PD-1 antibodies, promoted tumour remission. Collectively, we demonstrate that ER cholesterol sets a threshold for STING signalling through cholesterol-binding motifs in STING and we propose that this could be exploited for cancer immunotherapy.

The HIF transcription network exerts innate antiviral activity in neurons and limits brain inflammation

Pattern recognition receptors (PRRs) induce host defense but can also induce exacerbated inflammatory responses. This raises the question of whether other mechanisms are also involved in early host defense. Using transcriptome analysis of disrupted transcripts in herpes simplex virus (HSV)-infected cells, we find that HSV infection disrupts the hypoxia-inducible factor (HIF) transcription network in neurons and epithelial cells. Importantly, HIF activation leads to control of HSV replication. Mechanistically, HIF activation induces autophagy, which is essential for antiviral activity. HSV-2 infection in vivo leads to hypoxia in CNS neurons, and mice with neuron-specific HIF1/2α deficiency exhibit elevated viral load and augmented PRR signaling and inflammatory gene expression in the CNS after HSV-2 infection. Data from human stem cell-derived neuron and microglia cultures show that HIF also exerts antiviral and inflammation-restricting activity in human CNS cells. Collectively, the HIF transcription factor system senses virus-induced hypoxic stress to induce cell-intrinsic antiviral responses and limit inflammation.

Towards practical integration of MBR with electrochemical AOP: Improved biodegradability of real pharmaceutical wastewater and fouling mitigation

In the current study, we report enhanced treatment of real pharmaceutical wastewater by integration of Electrooxidation (EO) with Membrane Bio-Reactor (MBR) for the first time. Integrated pre-pilot EO-MBR plant consisted of a 3D printed electrochemical flowcell equipped with graphite electrodes installed in the effluent recirculation line of an MBR equipped with a hollow fiber membrane module. Results demonstrated that 5 V was the optimum voltage level for an isolated EO system. Isolated EO system led to 40% COD removal and 2.5 fold biodegradability index (BOD₅/COD) improvement after 24 hr treatment at the optimum voltage of 5 V and 160 mL.min^-1 flowrate. Almost complete removal of COD and BOD₅ was observed for the EO-MBR system with 160 mL.min^-1 recirculation rate and 24 hr HRT, while respective values were 60 and 87% for the MBR system at same operational conditions. Oxidation of pharmaceutical compounds identified in real wastewater and the fate of main oxidation-recalcitrant by-products were confirmed using liquid chromatography techniques. In addition, the integrated EO-MBR system led to significant membrane fouling mitigation with a 28 day extended operational time before reaching the Trans Membrane Pressure (TMP) limit value of 30 kPa. Measurements revealed reduced Extracellular Polymeric Substances (EPS) Concentration of membrane sludge cake layer of EO-MBR along with significant reduction of proteinaceous compounds in the LB-EPS fraction of cake layer in comparison with isolated MBR system. Fouling behavior improvement of the EO-MBR system was attributed to the electrophilic attack of electrochemically generated hydroxyl radicals to the electron-rich moieties of EPS organic foulants. Reduced proteinaceous/humic-like substances of LB-EPS from the cake layer were further confirmed by Emission Excitation matrix (EEM) and Fourier Transform InfraRed (FTIR) spectroscopic methods. The results of current research provide a helpful basis for future studies by elucidating the complex operating/fouling mechanism of integrated Advanced Oxidation Processes (AOPs) with MBR systems for enhanced treatment of organics polluted wastewaters with low biodegradability.

Integrated LC-MS and GC-MS-Based Metabolomics Reveal the Effects of Plant Competition on the Rye Metabolome

Plants compete with their neighbors about the limited resources available to them. Plants under induced stress resulting from competition may alter their metabolome to increase their resilience or enhance their defense mechanisms. In the present study, rye (Secale cereale) plants were cocultivated with different densities (3, 12, and 18 plants per pot) of Austrian pea (Pisum sativum subsp. arvense), hairy vetch (Vicia villosa), and Alexandrian clover (Trifolium alexandrinum L.) to elucidate the changes in the rye metabolome in response to the different levels of competition. Global metabolic profiling by liquid chromatography triple quadrupole tandem mass spectrometry (LC-QqQ-MS), liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS), and gas chromatography time-of-flight mass spectrometry (GC-TOF-MS) was performed on rye plants, and the acquired data were analyzed using uni- and multivariate statistics. Targeted analysis showed that a high level of competition reduced the concentration of aglycone benzoxazinoids (BXs) and increased glycoside BXs in rye roots. Untargeted metabolomics analysis indicated an increase in the rye root content of the allelopathic compounds 4-hydroxybenzoic acid and uracil in response to competition. Untargeted analysis of rye shoots revealed that the plant competition increased the d-pyroglutamic acid, which is an elicitor of reactive oxygen species (ROS). Our results have enhanced the knowledge of the biochemical response of plant species to cocultivation.

Mass spectrometry-based metabolomics unravel the transfer of bioactive compounds between rye and neighbouring plants

Translocation of metabolites between different plant species provides important hints in understanding the fate of bioactive root exudates. In the present study, targeted and untargeted mass spectrometry-based metabolomics was applied to elucidate the transfer of bioactive compounds between rye and several crops and weed species. Our results demonstrated that benzoxazinoids (BXs) synthesized by rye were taken up by roots of neighbouring plant species and translocated into their shoots. Furthermore, we showed that roots of rye plants took up compounds originating from neighbouring plants. Among the compounds taken up by rye roots, wogonin was detected in the rye shoot, which indicated a root-to-shoot translocation of this compound. Elucidating the transfer of bioactive compounds between plants is essential for understanding plant-plant interactions, developing natural pesticides and understanding their modes of action.

Determination of the Effect of Co-cultivation on the Production and Root Exudation of Flavonoids in Four Legume Species Using LC-MS/MS Analysis

Flavonoids play a key role in the regulation of plant-plant and plant-microbe interactions, and factors determining their release have been investigated in most of the common forage legumes. However, little is known about the response of flavonoid production and release to co-cultivation with other crop species. This study investigated alterations in the concentration of flavonoids in plant tissues and root exudates in four legumes [alfalfa (Medicago sativa L.), black medic (Medicago polymorpha L.), crimson clover (Trifolium incarnatum L.), and subterranean clover (Trifolium subterraneum L.)] co-cultivated with durum wheat [Triticum turgidum subsp. durum (Desf.) Husn.]. For this purpose, we carried out two experiments in a greenhouse, one with glass beads as growth media for root exudate extraction and one with soil as growth media for flavonoid detection in shoot and root biomass, using LC-MS/MS analysis. This study revealed that interspecific competition with wheat negatively affected legume growth and led to a significant reduction in shoot and root biomass compared with the same legume species grown in monoculture. In contrast, the concentration of flavonoids significantly increased both in legume biomass and in root exudates. Changes in flavonoid concentration involved daidzein, genistein, medicarpin, and formononetin, which have been found to be involved in legume nodulation and regulation of plant-plant interaction. We hypothesize that legumes responded to the co-cultivation with wheat by promoting nodulation and increasing exudation of allelopathic compounds, respectively, to compensate for the lack of nutrients caused by the presence of wheat in the cultivation system and to reduce the competitiveness of neighboring plants. Future studies should elucidate the bioactivity of flavonoid compounds in cereal-legume co-cultivation systems and their specific role in the nodulation process and inter-specific plant interactions such as potential effects on weeds.

Root-Exuded Benzoxazinoids: Uptake and Translocation in Neighboring Plants

Plants have evolved advanced chemical defense mechanisms, including root exudation, which enable them to respond to changes occurring in their surroundings rapidly. Yet, it remains unresolved how root exudation affects belowground plant-plant interactions. The objective of this study was to elucidate the fate of benzoxazinoids (BXs) exuded from the roots of rye (Secale cereale L.) plants grown with hairy vetch (Vicia villosa). A rapid method that allows nondestructive and reproducible chemical profiling of the root exudates was developed. Targeted chemical analysis with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was performed to investigate the changes in the composition and concentration of BXs in the rye plant, and its root exudate in response to cocultivation with hairy vetch. Furthermore, hairy vetch plants were screened for the possible uptake of BXs from the rhizosphere and their translocation to the shoot. Rye significantly increased the production and root exudation of BXs, in particular 2-β-d-glucopyranosyloxy-4-hydroxy-1,4-benzoxazin-3-one (DIBOA-glc) and 2-β-d-glucopyranosyloxy-4-hydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA-glc), in response to cocultivation with hairy vetch. DIBOA-glc and DIMBOA-glc were absorbed by the roots of the cocultivated hairy vetch plants and translocated to the shoots. These findings will strongly improve our understanding of the exudation of BXs from the rye plant and their role in interaction with other plant species.

Natural herbicide activity of Satureja hortensis L. essential oil nanoemulsion on the seed germination and morphophysiological features of two important weed species

The aim of the present study was to obtain an oil/water (O/W) nanoemulsion (NE) containing garden savory (Satureja hortensis) essential oil (EO) and evaluating its herbicidal activity against Amaranthus retroflexus and Chenopodium album. Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) were employed to determine the chemical composition of the EO. Carvacrol (55.6%) and γ-terpinene (31.9%) were the major EO components. Low energy method was applied, allowing achievement of EO nanodroplets. The NE also presented low polydispersity, and the mean droplet was below 130nm even after storage for 30d. Laboratory tests showed that the NE at different concentrations (100, 200, 400, 800, and 1000μL.L^-1) significantly (P≤0.05) reduced the germination indices and the seedling's growth in dose-response. The inhibitory effect was the greatest at 800μL.L^-1 NE. Overall, root length was more inhibited as compared to shoot length. Post-emergence application of NE at different concentrations (1000, 2000, 3000, 4000 and 5000μL.L^-1 of EO) on 2-4 true leaves' stage of the weeds caused significant (P≤0.05) decrease in the growth factors in dose-dependent manner. Complete lethality was observed by 4000μL.L^-1 NE sprayed on the weeds. Spraying of NE significantly (P≤0.05) reduced chlorophyll content in the tested weeds. Increasing in relative electrolyte leakage (REL) 1 and 5d after treatment represented significant cell membrane disruption and increased cell membrane permeability. Transmission electron microscope (TEM) pictures confirmed NE droplet size and demonstrated membrane destruction. The study approved that the NE of S. hortensis EO has herbicidal properties as it has high phytotoxic effect, and interferes with the germination, growth and physiological processes of the weeds. The production of NE from S. hortensis EO is a low energy method that offers a promising practical natural herbicide for weed control in organic agricultural systems.

Biodegradation kinetics and interactions of styrene and ethylbenzene as single and dual substrates for a mixed bacterial culture

This study examined biodegradation kinetics of styrene and ethylbenzene as representatives of alkenylbenzenes and mono-alkylbenzenes, respectively. The compounds were studied independently and as binary mixtures using a series of aerobic batch degradation experiments introduced by acclimatized mix culture. Initial concentration of styrene and ethylbenzene in the liquid phase vacillated from 0 to 220 mg/l. The Andrew model was applied for the biodegradation of individual substrates and the estimated constants of the equation for styrene and ethylbenzene were μmax = 0.1581, 0.2090 (1/h), KS =25.91, 37.77 (mg/L), KI =13.15, 62.62 (mg/L), respectively. The accomplished parameters from single substrate degradation tests were used to predict possible interaction factors achieved from dual substrate experiments. The Sum Kinetics with Interaction Parameters (SKIP) model and the purely competitive enzyme kinetics model were employed to evaluate any interactions. The SKIP model was found to accurately describe these interactions. Moreover, it was revealed that ethylbenzene plays an influential role on styrene consumption (e.g. IE,S = 1.64) compared to styrene which has insignificant inhibitory effect on ethylbenzene usage (e.g. IS,E =0.4) . The active site differences for styrene and ethylbenzene biodegradation and the pathway variations for biodegradation are among the major potential reasons for failure of the estimation that occurred in purely competitive kinetics model. This study is the first to calculate the interactions between styrene and ethylbenzene.

Upgrading activated sludge systems and reduction in excess sludge

Most of 200 Activated Sludge Plant in Iran are overloaded and as a result, their efficiency is low. In this work, a pilot plant is manufactured and put into operation in one of the wastewater treatment plants in the west of Tehran. Instead of conventional activated sludge, a membrane bioreactor and an upflow anaerobic sludge blanket reactor used as a pretreatment unit in this pilot. For the sake of data accuracy and precision, an enriched municipal wastewater was opted as an influent to the pilot. Based on the attained result, the optimum retention time in this system was 4h, and the overall COD removal efficiency was 98%. As a whole, the application of this retrofit would increase the plant's capacity by a factor of 5 and reducing the excess sludge by a factor of 10. The sludge volume index in the anaerobic reactor was about 12 after granulation occurred.