[Regulation of mitophagy and mitochondrial biogenesis by monocarbonyl analogues of curcumin in the cerebral cortex of rats in experimental Alzheimer's disease]. / Regulyatsiya mitofagii i mitokhondrial'nogo biogeneza monokarbonil'nymi analogami kurkumina v kore bol'shikh polusharii golovnogo mozga krys v usloviyakh eksperimental'noi bolezni Al'tsgeimera.

OBJECTIVE: To evaluate the effect of monocarbonyl analogues of curcumin on changes in the processes of mitophagy and mitochondrial biogenesis in the cerebral cortex of rats with experimental Alzheimer's disease. MATERIAL AND METHODS: Alzheimer's disease was modeled in Wistar rats of both sexes by injection of ß-amyloid fragments into the hippocampus of the animal. Compounds (1E, 4E)-1.5-bis (3.4.5-trimethoxyphenyl) penta-1.4-diene-3-one (AZBAX4 code) and (1E, 4E)-1.5-bis (2.4.6-trimethoxyphenyl) penta-1.4-diene-3-one (AZBAX6 code) at a dose of 20 mg/ kg (orally) and the reference drug donepezil at a dose of 50 mg/kg (orally) were administered for 30 days, after which changes in the activity of succinate dehydrogenase, cytochrome-c oxidase and citrate synthase as enzymatic biomarkers of mitochondrial biogenesis and mitophagy, respectively, were evaluated in the mitochondrial fraction of the cerebral cortex. RESULTS: The administration of AZBAX4 and AZBAX6 compounds led to an increase in the activity of succinate dehydrogenase; cytochrome-c oxidase, as well as citrate synthase in relation to the same indicators of the group of untreated animals. The use of the analyzed compounds was equally effective in both female and male rats. At the same time, it should be noted that the analyzed compounds significantly exceeded the activity level of the reference donepezil. CONCLUSION: AZBAX4 and AZBAX6 contribute to an increase in the intensity of mitochondrial biogenesis and mitophagy reactions in the cerebral cortex of rats with Alzheimer's disease, which makes them potentially effective neuroprotective compounds.

The effect of enterosgel on the activity of energy supply processes in rats at the same time affected by malathion and tetrachlormethane.

OBJECTIVE: Aim: The aim of the study was to investigate the activity of bioenergetic processes in rats under conditions of simultaneous exposure to malathion and carbon tetrachloride and after the use of enterosgel. PATIENTS AND METHODS: Materials and Methods: Experiments were conducted on rats. The rats were divided into nine groups.Malathion was administered daily (for 30 days) at a dose of 20 mg / kg body weight of the animal. Tetrachloromethane was administered twice (every other day) as a 50% oil solution at a dose of 1.0 ml / kg body weight. The intensity of energy supply processes was assessed by the activity of succinate dehydrogenase and cytochrome oxidase, impaired carbohydrate metabolism in terms of glucose and glycogen. RESULTS: Results: It was noted that succinate dehydrogenase activity in the liver decreased 2 times, in the myocardium - 1.6 times. On the thirty and seventh day of administration of toxicants after enterosorbent use, succinate dehydrogenase activity increased in the liver by 20%, cytochrome oxidase by 27%, in the myocardium - by 31% and 23%, respectively. The content of glucose in the serum after exposure to toxicants increased maximally (2.4 times) at the end of the study. In contrast, the glycogen content in the liver decreased by 48%, in the myocardium by 13%. The use of enterosgel resulted in a decrease in serum glucose. CONCLUSION: Conclusions: The use of enterosgel leads to the restoration of energy processes in the body of affected rats, which is confirmed by increased activity of mitochondrial enzymes, lowering glucose and increasing glycogen in the studied organs.

Differential expression of nuclear-derived mitochondrial succinate dehydrogenase genes in metabolically active buffalo tissues.

BACKGROUND: Buffaloes are crucial to agriculture, yet mitochondrial biology in these animals is less studied compared to humans and laboratory animals. This research examines tissue-specific variations in mitochondrial succinate dehydrogenase (SDH) gene expression across buffalo kidneys, hearts, brains, and ovaries. Understanding these variations sheds light on mitochondrial energy metabolism and its impact on buffalo health and productivity, revealing insights into enzyme regulation and potential improvements in livestock management. MATERIALS AND METHODS: RNA-seq data from buffalo kidney, heart, brain, and ovary tissues were reanalyzed to explore mitochondrial SDH gene expression. The expression of SDH subunits (SDHA, SDHB, SDHC, SDHD) and assembly factors (SDHAF1, SDHAF2, SDHAF3, SDHAF4) was assessed using a log2 fold-change threshold of + 1 for up-regulated and - 1 for down-regulated transcripts, with significance set at p < 0.05. Hierarchical clustering and differential expression analyses were performed to identify tissue-specific expression patterns and regulatory mechanisms, while Gene Ontology and KEGG pathway analyses were conducted to uncover functional attributes and pathway enrichments across different tissues. RESULTS: Reanalysis of RNA-seq data from different tissues of healthy female buffaloes revealed distinct expression patterns for SDH subunits and assembly factors. While SDHA, SDHB, and SDHC showed variable expression across tissues, SDHAF2, SDHAF3, and SDHAF4 exhibited tissue-specific profiles. Significant up-regulation of SDHA, SDHB, and several assembly factors was observed in specific tissue comparisons, with fewer down-regulated transcripts. Gene ontology and KEGG pathway analyses linked the up-regulated transcripts to mitochondrial ATP synthesis and the respiratory electron transport chain. Notably, tissue-specific variations in mitochondrial function were particularly evident in the ovary. CONCLUSION: This study identifies distinct SDH gene expression patterns in buffalo tissues, highlighting significant down-regulation of SDHA, SDHB, SDHC, and assembly factors in the ovary. These findings underscore the critical role of mitochondria in tissue-specific energy production and metabolic regulation, suggest potential metabolic adaptations, and emphasize the importance of mitochondrial complex II. The insights gained offer valuable implications for improving feed efficiency and guiding future research and therapies for energy metabolism disorders.

Design, Synthesis, and Biological Activity Evaluation of Eco-Friendly Rosin-Diamide-Based Fungicides as Potential Succinate Dehydrogenase Inhibitors for Sustainable Crop Protection.

To develop novel succinate dehydrogenase (SDH) inhibitors for sustainable crop protection, a series of dehydroabietyl-diamide-based fungicides (a total of 21) were designed. In vitro fungicidal activity measurement showed that compound 3u exhibited excellent fungicidal activity against Valsa mali (half-maximal effective concentration, EC50 = 0.195 µg/mL), surpassing that of the positive control carbendazim (EC50 = 1.35 µg/mL). The in vivo fungicidal activity assessment suggested that 3u exhibited a protective effect on apple branches (69.7-48.1%) and apples (94.6-56.6%). Furthermore, biosafety evaluation indicated that 3u was significantly environmentally friendly toward zebrafish. Subsequently, morphology, physiology, and molecular docking were investigated to elucidate the mode of action of 3u against V. mali. Results demonstrated a strong binding between 3u and SDH, resulting in decreased SDH activity (half-maximal inhibitory concentration, IC50 = 11.7 µg/mL). Moreover, 3u disrupted the mycelial cell membrane and accelerated electrolyte leakage, ultimately resulting in the death of V. mali. These findings suggest that 3u could serve as a potent SDH inhibitor for sustainable crop protection.

Immunometabolic Circuits in Infection for Advancing Host Directed Therapies.

Immuno-metabolism is a pivotal determinant in the progression of leishmaniasis. Synthetic biology-based approach has garnered significant attention as a step toward therapeutic intervention targeting host-associated factors that drive leishmaniasis. Synthetic biology entails the engineering of genetic components in an orthogonal and modular manner to precisely modulate biological systems, imparting novel functions to cells. In the presented study, elucidation of a systematic pipeline for the development of an inducible tetracycline-controlled (TetON)-based synthetic circuit was aimed at delivering succinate dehydrogenase as a therapeutic agent to facilitate the elimination of intracellular Leishmania parasites. The outlined protocol describes the designing of a synthetic circuit and its subsequent validation. The proposed strategy also concentrates on the incorporation of synthetic circuits in the plasmid backbone as a delivery vehicle. Additionally, delivery machinery employing polyplexes-based nano-particles for the delivery of synthetic circuits was used in murine macrophage cell lines without compromising the cellular morphology. Standardization of the method was conducted for selecting transfected cells and determining optimal induction concentration for synthetic circuit expression. Observations reveal a distinct reduction in intracellular parasite burden in transfected cells compared to infected cells. Pro-inflammatory cytokines were expressed post-infection in synthetic circuit transfected and induced cells as a mechanism to promote parasite elimination. This underscores the synthetic biology-based method as a potent approach in leishmaniasis by targeting host factors associated with disease progression.

ß-Cyclodextrin-optimized supramolecular nanovesicles enhance the droplet/foliage interface interactions and inhibition of succinate dehydrogenase (SDH) for efficient treatment of fungal diseases.

BACKGROUND: Plant fungal diseases present a major challenge to global agricultural production. Despite extensive efforts to develop fungicides, particularly succinate dehydrogenase inhibitors (SDHIs), their effectiveness is often limited by poor retention of fungicide droplets on hydrophobic leaves. The off-target losses and unintended release cause fungal resistance and severe environmental pollution. RESULTS: To update the structure of existing SDHIs and synchronously realize the efficient utilization, we have employed a sophisticated supramolecular strategy to optimize a structurally novel SDH inhibitor (AoH25), creating an innovative supramolecular SDH fungicide (AoH25@ß-CD), driven by the host-guest recognition principle between AoH25 and ß-cyclodextrin (ß-CD). Intriguingly, AoH25@ß-CD self-assembles into biocompatible supramolecular nanovesicles, which reinforce the droplet/foliage (liquid-solid) interface interaction and the effective wetting and retention on leaf surfaces, setting the foundation for enhancing fungicide utilization. Mechanistic studies revealed that AoH25@ß-CD exhibited significantly higher inhibition of SDH (IC50 = 1.56 µM) compared to fluopyram (IC50 = 244.41 µM) and AoH25 alone (IC50 = 2.29 µM). Additionally, AoH25@ß-CD increased the permeability of cell membranes in Botryosphaeria dothidea, facilitating better penetration of active ingredients into pathogenic cells. Further experimental outcomes confirmed that AoH25@ß-CD was 88.5% effective against kiwifruit soft rot at a low-dose of 100 µg mL-1, outperforming commercial fungicides such as fluopyram (52.4%) and azoxystrobin (65.4%). Moreover, AoH25@ß-CD showed broad-spectrum bioactivity against oilseed rape sclerotinia, achieving an efficacy of 87.2%, outstripping those of fluopyram (48.7%) and azoxystrobin (76.7%). CONCLUSION: This innovative approach addresses key challenges related to fungicide deposition and resistance, improving the bioavailability of agricultural chemicals. The findings highlight AoH25@ß-CD as a novel supramolecular SDH inhibitor, demonstrating its potential as an efficient and sustainable solution for plant disease management.

Polyamine Pathway Inhibitor DENSPM Suppresses Lipid Metabolism in Pheochromocytoma Cell Line.

Pheochromocytomas (PCCs) are tumors arising from chromaffin cells in the adrenal medulla, and paragangliomas (PGLs) are tumors derived from extra-adrenal sympathetic or parasympathetic paraganglia; these tumors are collectively referred to as PPGL cancer. Treatment for PPGL primarily involves surgical removal of the tumor, and only limited options are available for treatment of the disease once it becomes metastatic. Human carriers of the heterozygous mutations in the succinate dehydrogenase subunit B (SDHB) gene are susceptible to the development of PPGL. A physiologically relevant PCC patient-derived cell line hPheo1 was developed, and SDHB_KD cells carrying a stable short hairpin knockdown of SDHB were derived from it. An untargeted metabolomic approach uncovered an overactive polyamine pathway in the SDHB_KD cells that was subsequently fully validated in a large set of human SDHB-mutant PPGL tumor samples. We previously reported that treatment with the polyamine metabolism inhibitor N1,N11-diethylnorspermine (DENSPM) drastically inhibited growth of these PCC-derived cells in culture as well as in xenograft mouse models. Here we explored the mechanisms underlying DENSPM action in hPheo1 and SDHB_KD cells. Specifically, by performing an RNAseq analysis, we have identified gene expression changes associated with DENSPM treatment that broadly interfere with all aspects of lipid metabolism, including fatty acid (FA) synthesis, desaturation, and import/uptake. Furthermore, by performing an untargeted lipidomic liquid chromatography-mass spectrometry (LC/MS)-based analysis we uncovered specific groups of lipids that are dramatically reduced as a result of DENSPM treatment. Specifically, the bulk of plasmanyl ether lipid species that have been recently reported as the major determinants of cancer cell fate are notably decreased. In summary, this work suggests an intersection between active polyamine and lipid pathways in PCC cells.

Identification of Chemical Scaffolds That Inhibit the Mycobacterium tuberculosis Respiratory Complex Succinate Dehydrogenase.

Drug-resistant Mycobacterium tuberculosis is a significant cause of infectious disease morbidity and mortality for which new antimicrobials are urgently needed. Inhibitors of mycobacterial respiratory energy metabolism have emerged as promising next-generation antimicrobials, but a number of targets remain unexplored. Succinate dehydrogenase (SDH), a focal point in mycobacterial central carbon metabolism and respiratory energy production, is required for growth and survival in M. tuberculosis under a number of conditions, highlighting the potential of inhibitors targeting mycobacterial SDH enzymes. To advance SDH as a novel drug target in M. tuberculosis, we utilized a combination of biochemical screening and in-silico deep learning technologies to identify multiple chemical scaffolds capable of inhibiting mycobacterial SDH activity. Antimicrobial susceptibility assays show that lead inhibitors are bacteriostatic agents with activity against wild-type and drug-resistant strains of M. tuberculosis. Mode of action studies on lead compounds demonstrate that the specific inhibition of SDH activity dysregulates mycobacterial metabolism and respiration and results in the secretion of intracellular succinate. Interaction assays demonstrate that the chemical inhibition of SDH activity potentiates the activity of other bioenergetic inhibitors and prevents the emergence of resistance to a variety of drugs. Overall, this study shows that SDH inhibitors are promising next-generation antimicrobials against M. tuberculosis.

[The role of mitochondrial dysfunction in the stabilization of the glaucomatous process]. / Znachenie mitokhondrial'noi disfunktsii v stabilizatsii glaukomnogo protsessa.

Many key aspects of retinal ganglion cell (RGC) neurodegeneration in glaucoma are associated with mitochondrial dysfunction. Understanding the mechanisms and relationships between structural and functional changes in mitochondria would be beneficial for developing mitochondria-targeted therapeutic strategies to protect RGCs from glaucomatous neurodegeneration. PURPOSE: This study determines the extent of mitochondrial dysfunction in patients with primary open-angle glaucoma (POAG) and evaluates the potential for stabilizing the glaucomatous process by improving mitochondrial functional activity and energy production by therapy with Mexidol and Mexidol FORTE 250. MATERIAL AND METHODS: The study included 80 patients with moderate POAG with compensated intraocular pressure and 20 healthy volunteers. The extent of mitochondrial dysfunction was assessed by measuring the activity levels of mitochondrial enzymes: succinate dehydrogenase (SDH) and α-glycerophosphate dehydrogenase (α-GPDH) in peripheral blood lymphocytes using cytochemical analysis and cytometric morphology and density analysis (cytomorphodensitometry). Patients in the main group received sequential therapy with Mexidol as follows: Mexidol solution for intravenous and intramuscular administration at 50 mg/ml, 300 mg daily intramuscularly for 14 days, followed by Mexidol FORTE 250 tablets, one tablet three times daily for 56 days. Stabilization of glaucomatous optic neuropathy during treatment was evaluated using a comprehensive set of perimetric, electrophysiological, and structural-topographical methods at 14, 56, and 90 days. RESULTS: Sequential therapy in the main group resulted in a significant increase in mitochondrial enzyme activity at 14 and 56 days compared to baseline, with a gradual regression by the end of the observation period (90 days). This was accompanied by an increase in the number of mitochondria and an increase in their optical density as measured by cytomorphodensitometry. The improvement in mitochondrial enzyme activity at 14 and 56 days was associated with positive changes in the structural and functional parameters of the retina, as evidenced by static perimetry, optical coherence tomography, and a series of electrophysiological tests. CONCLUSION: The obtained data can be used to optimize POAG therapy by reducing mitochondrial dysfunction and stabilizing glaucomatous optic neuropathy.

Discovery of Benzothiazol-2-ylthiophenylpyrazole-4-carboxamides as Novel Succinate Dehydrogenase Inhibitors.

Succinate dehydrogenase (SDH) has been considered an ideal target for discovering fungicides. To develop novel SDH inhibitors, in this work, 31 novel benzothiazol-2-ylthiophenylpyrazole-4-carboxamides were designed and synthesized using active fragment exchange and a link approach as promising SDH inhibitors. The findings from the tests on antifungal activity indicated that most of the synthesized compounds displayed remarkable inhibition against the fungi tested. Compound Ig N-(2-(((5-chlorobenzo[d]thiazol-2-yl)thio)methyl)phenyl)-3-(difluoromethyl)-1-methyl-1H-yrazole-4-carboxamide, with EC50 values against four kinds of fungi tested below 10 µg/mL and against Cercospora arachidicola even below 2 µg/mL, showed superior antifungal activity than that of commercial fungicide thifluzamide, and specifically compounds Ig and Im were found to show preventative potency of 90.6% and 81.3% against Rhizoctonia solani Kühn, respectively, similar to the positive fungicide thifluzamide. The molecular simulation studies suggested that hydrophobic interactions were the main driving forces between ligands and SDH. Encouragingly, we found that compound Ig can effectively promote the wheat seedlings and the growth of Arabidopsis thaliana. Our further studies indicated that compound Ig could stimulate nitrate reductase activity in planta and increase the biomass of plants.

Stereoselective Bioactivity and Action Mechanism of the Fungicide Isopyrazam.

Understanding the stereoselective bioactivity of chiral pesticides is crucial for accurately evaluating their effectiveness and optimizing their use. Isopyrazam, a widely used chiral SDHI fungicide, has been studied for its antifungal activity only at the racemic level. Therefore, to clarify the highly bioactive isomers, the stereoselective bioactivity of isopyrazam isomers against four typical phytopathogens was studied for the first time. The bioactivity ranking of the isomers was trans-1S,4R,9R-(+)-isopyrazam > cis-1R,4S,9R-(+)-isopyrazam > trans-1R,4S,9S-(-)-isopyrazam > cis-1S,4R,9S-(-)-isopyrazam. SDH activity was assessed by molecular docking simulation and actual detection to confirm the reasons for stereoselective bioactivity. The results suggest that the stereoselective bioactivity of isopyrazam is largely dependent on the differential binding ability of each isomer to the SDH ubiquitin-binding site, located within a cavity formed by the iron-sulfur subunit, the cytochrome b560 subunit, and the cytochrome b small subunit. Moreover, to reveal the molecular mechanism of isopyrazam stereoselectively affecting mycelial growth, the contents of succinic acid, fumaric acid, and ATP were measured. Furthermore, by measuring exospore polysaccharides and oxalic acid content, it was determined that 1S,4R,9R-(+)- and 1R,4S,9R-(+)-isopyrazam more strongly inhibited the ability of Sclerotinia sclerotiorum to infect plants. The findings provided essential data for the development of high-efficiency isopyrazam fungicides and offered a methodological reference for analyzing the enantioselective activity mechanism of SDHI fungicides.

Succinate dehydrogenase-complex II regulates skeletal muscle cellular respiration and contractility but not muscle mass in genetically induced pulmonary emphysema.

Reduced skeletal muscle mass and oxidative capacity coexist in patients with pulmonary emphysema and are independently associated with higher mortality. If reduced cellular respiration contributes to muscle atrophy in that setting remains unknown. Using a mouse with genetically induced pulmonary emphysema that recapitulates muscle dysfunction, we found that reduced activity of succinate dehydrogenase (SDH) is a hallmark of its myopathic changes. We generated an inducible, muscle-specific SDH knockout mouse that demonstrates lower mitochondrial oxygen consumption, myofiber contractility, and exercise endurance. Respirometry analyses show that in vitro complex I respiration is unaffected by loss of SDH subunit C in muscle mitochondria, which is consistent with the pulmonary emphysema animal data. SDH knockout initially causes succinate accumulation associated with a down-regulated transcriptome but modest proteome effects. Muscle mass, myofiber type composition, and overall body mass constituents remain unaltered in the transgenic mice. Thus, while SDH regulates myofiber respiration in experimental pulmonary emphysema, it does not control muscle mass or other body constituents.

[Endothelial cells and fibroblasts mediate the microenvironmental regulatory network of carotid body paraganglioma].

Objective:To explore the gene expression characteristics of endothelial cells and fibroblasts in the microenvironment of SDHD-mutated carotid body tumors（SDHD-CBT）, to fine the functional enrichment of each subcluster, and to further explore the network of cell-cell interactions in the microenvironment of SDHD-CBT. Methods:The bioinformatics analysis was used to download and reanalyze the single-nuclear RNA sequencing data of SDHD-CBT, SDHB mutated thoracic and abdominal paraganglioma（SDHB-ATPGL）, SDHB-CBT, and normal adrenal medulla（NAM）, to clarify the information of cell populations of the samples. We focused on exploring the gene expression profiles of endothelial cells and fibroblasts subclusters, and performed functional enrichment analysis based on Gene Ontology（GO） resources. CellChat was used to compare the cell-cell interactions networks of different clinical samples and predict significant signaling pathways in SDHD-CBT. Results:A total of 7 cell populations were profiled. The main subtypes of endothelial cells in SDHD-CBT are arterial and venous endothelial cells, and the main subtypes of fibroblasts are myofibroblasts and pericytes. Compared to NAM, SDHB-CBT and SDHB-ATPGL, cell communication involving endothelial cells and fibroblasts in SDHD-CBT is more abundant, with significant enrichment in pathways such as FGF, PTN, WNT, PROS, PERIOSTIN, and TGFb. Conclusion:Endothelial cells and fibroblasts in SDHD-CBT are heterogeneous and involved in important cellular interactionprocesses, in which the discovery of FGF，PTN，WNT，PROS，PERIOSTIN and TGFb signals may play an important role in the regulation of microenvironment of SDHD-CBT.

Design, synthesis and biological activity evaluation of eco-friendly rosin-based fungicides for sustainable crop protection.

BACKGROUND: Utilizing fungicides to protect crops from diseases is an effective method, and novel eco-friendly plant-derived fungicides with high efficiency and low toxicity are urgent requirements for sustainable crop protection. RESULT: Two series of rosin-based fungicides (totally 35) were designed and synthesized. In vitro fungicidal activity revealed that Compound 6a (Co. 6a) effectively inhibited the growth of Valsa mali [median effective concentration (EC50) = 0.627 µg mL-1], and in vivo fungicidal activity suggested a significant protective efficacy of Co. 6a in protecting both apple branches (35.12% to 75.20%) and apples (75.86% to 90.82%). Quantum chemical calculations (via density functional theory) results indicated that the primary active site of Co. 6a lies in its amide structure. Mycelial morphology and physiology were investigated to elucidate the mode-of-action of Co. 6a, and suggested that Co. 6a produced significant cell membrane damage, accelerated electrolyte leakage, decreased succinate dehydrogenase (SDH) protein activity, and impaired physiological and biochemical functions, culminating in mycelial mortality. Molecular docking analysis revealed a robust binding energy (ΔE = -7.29 kcal mol-1) between Co. 6a and SDH. Subsequently, biosafety evaluations confirmed the environmentally-friendly nature of Co. 6a via the zebrafish model, yet toxicological results indicated that Co. 6a at median lethal concentration [LC50(96)] damaged the gills, liver and intestines of zebrafish. CONCLUSION: The above research offers a theoretical foundation for exploiting eco-friendly rosin-based fungicidal candidates in sustainable crop protection. © 2024 Society of Chemical Industry.

Antibacterial Effect of Euryale ferox Seed Shell Polyphenol Extract on Salmonella Typhimurium.

This study aimed to evaluate the effects of Euryale ferox Seed Shell Polyphenol Extract (EFSSPE) on a foodborne pathogenic bacterium. EFSSPE showed antimicrobial activity toward Salmonella Typhimurium CICC 22956; the minimum inhibitory concentration of EFSSPE was 1.25 mg/mL, the inhibition curve also reflected the inhibitory effect of EFSSPE on the growth of S. Typhimurium. Detection of alkaline phosphatase outside the cell revealed that EFSSPE treatment damaged the cell wall integrity of S. Typhimurium. EFSSPE also altered the membrane integrity, thereby causing leaching of 260-nm-absorbing material (bacterial proteins and DNA). Moreover, the activities of succinate dehydrogenase and malate dehydrogenase were inhibited by EFSSPE. The hydrophobicity and clustering ability of cells were affected by EFSSPE. Scanning electron microscopy showed that EFSSPE treatment damaged the morphology of the tested bacteria. These results indicate that EFSSPE can destroy the cell wall integrity and alter the permeability of the cell membrane of S. Typhimurium.

Attenuated frontotemporal brain activation during cognitive tasks is associated with lower succinate dehydrogenase protein levels in patients with major depressive disorder.

BACKGROUND: Previous studies have shown a lower hemodynamic response in patients with major depressive disorder (MDD) during cognitive tasks. However, the mechanism underlying impaired hemodynamic and neural responses to cognitive tasks in MDD patients remains unclear. Succinate dehydrogenase (SDH) is a key biomarker of mitochondrial energy generation, and it can affect the hemodynamic response via the neurovascular coupling effect. In the current study, cerebral hemodynamic responses were detected during verbal fluency tasks (VFTs) via functional near-infrared spectroscopy (fNIRS) and SDH protein levels were examined in serum from MDD patients to quickly identify whether these hemodynamic alterations were related to mitochondrial energy metabolism. METHODS: Fifty patients with first-episode drug-naïve MDD and 42 healthy controls (HCs) were recruited according to inclusion and exclusion criteria. The 17-item Hamilton Depression Rating Scale (17-HDRS), Hamilton Anxiety Rating Scale (HAMA) and Inventory of Depressive Symptomatology-Self Report (IDS-SR) were used to assess the clinical symptoms of the patients. All participants underwent fNIRS measurements to evaluate cerebral hemodynamic responses in the frontal and temporal cortex during VFTs; moreover, SDH protein levels were measured using an enzyme-linked immunosorbent assay. RESULTS: Activation in the frontal-temporal brain region during the VFTs was lower in patients with MDD than in HCs. The SDH level in the serum of MDD patients was also significantly lower than that in HCs (p = 0.003), which significantly affected right lateral frontal (p = 0.025) and right temporal (p = 0.022) lobe activation. Both attenuated frontal-temporal activation during the VFTs (OR = 1.531) and lower SDH levels (OR = 1.038) were risk factors for MDD. CONCLUSIONS: MDD patients had lower cerebral hemodynamic responses to VFTs; this was associated with mitochondrial dysfunction, as indicated by SDH protein levels. Furthermore, attenuated hemodynamic responses in frontotemporal regions and lower SDH levels increased the risk for MDD. LIMITATIONS: The sample size is relatively small. SDH protein levels in peripheral blood may not necessarily reflect mitochondrial energy generation in the central nervous system.

Characterisation of an Adult Zebrafish Model for SDHB-Associated Phaeochromocytomas and Paragangliomas.

Phaeochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumours arising from chromaffin cells. Pathogenic variants in the gene succinate dehydrogenase subunit B (SDHB) are associated with malignancy and poor prognosis. When metastases arise, limited treatment options are available. The pathomechanism of SDHB-associated PPGL remains largely unknown, and the lack of suitable models hinders therapy development. Germline heterozygous SDHB pathogenic variants predispose to developing PPGLs with a life-long penetrance of around 50%. To mimic the human disease phenotype, we characterised adult heterozygous sdhb mutant zebrafish as a potential model to study SDHB-related PPGLs. Adult sdhb mutant zebrafish did not develop an obvious tumour phenotype and were anatomically and histologically like their wild-type siblings. However, sdhb mutants showed significantly increased succinate levels, a major hallmark of SDHB-related PPGLs. While basal activity was increased during day periods in mutants, mitochondrial complex activity and catecholamine metabolite levels were not significantly different. In conclusion, we characterised an adult in vivo zebrafish model, genetically resembling human carriers. Adult heterozygous sdhb mutants mimicked their human counterparts, showing systemic elevation of succinate levels despite the absence of a tumour phenotype. This model forms a promising basis for developing a full tumour phenotype and gaining knowledge of the pathomechanism behind SDHB-related PPGLs.

The New Nematicide Cyclobutrifluram Targets the Mitochondrial Succinate Dehydrogenase Complex in Bursaphelenchus xylophilus.

Bursaphelenchus xylophilus is a dangerous quarantine pest that causes extensive damage to pine ecosystems worldwide. Cyclobutrifluram, a succinate dehydrogenase inhibitor (SDHI), is a novel nematicide introduced by Syngenta in 2013. However, the nematocidal effect of cyclobutrifluram against plant-parasitic nematodes remains underexplored. Therefore, here, we aim to address this knowledge gap by evaluating the toxicity, effects, and mode of action of cyclobutrifluram on B. xylophilus. The result shows that cyclobutrifluram is the most effective agent, with an LC50 value of 0.1078 mg·L-1. At an LC20 dose, it significantly reduced the population size to 10.40 × 103 ± 737.56-approximately 1/23 that of the control group. This notable impact may stem from the agent's ability to diminish egg-laying and hatching rates, as well as to impede the nematodes' development. In addition, it has also performed well in the prevention of pine wilt disease, significantly reducing the incidence in greenhouses and in the field. SDH consists of a transmembrane assembly composed of four protein subunits (SDHA to SDHD). Four sdh genes were characterized and proved by RNAi to regulate the spawning capacity, locomotion ability, and body size of B. xylophilus. The mortality of nematodes treated with sdhc-dsRNA significantly decreased upon cyclobutrifluram application. Molecular docking further confirmed that SDHC, a cytochrome-binding protein, is the target. In conclusion, cyclobutrifluram has a good potential for trunk injection against B. xylophilus. This study provides valuable information for the screening and application of effective agents in controlling and preventing PWD in forests.

Investigating the therapeutic effects of nimodipine on vasogenic cerebral edema and blood-brain barrier impairment in an ischemic stroke rat model.

Vasogenic brain edema, a potentially life-threatening consequence following an acute ischemic stroke, is a major clinical problem. This research aims to explore the therapeutic benefits of nimodipine, a calcium channel blocker, in mitigating vasogenic cerebral edema and preserving blood-brain barrier (BBB) function in an ischemic stroke rat model. In this research, animals underwent the induction of ischemic stroke via a 60-min blockage of the middle cerebral artery and treated with a nonhypotensive dose of nimodipine (1 mg/kg/day) for a duration of five days. The wet/dry method was employed to identify cerebral edema, and the Evans blue dye extravasation technique was used to assess the permeability of the BBB. Furthermore, immunofluorescence staining was utilized to assess the protein expression levels of matrix metalloproteinase-9 (MMP-9) and intercellular adhesion molecule-1 (ICAM-1). The study also examined mitochondrial function by evaluating mitochondrial swelling, succinate dehydrogenase (SDH) activity, the collapse of mitochondrial membrane potential (MMP), and the generation of reactive oxygen species (ROS). Post-stroke administration of nimodipine led to a significant decrease in cerebral edema and maintained the integrity of the BBB. The protective effects observed were associated with a reduction in cell apoptosis as well as decreased expression of MMP-9 and ICAM-1. Furthermore, nimodipine was observed to reduce mitochondrial swelling and ROS levels while simultaneously restoring MMP and SDH activity. These results suggest that nimodipine may reduce cerebral edema and BBB breakdown caused by ischemia/reperfusion. This effect is potentially mediated through the reduction of MMP-9 and ICAM-1 levels and the enhancement of mitochondrial function.

Various amino acid substitutions in succinate dehydrogenase complex regulating differential resistance to pydiflumetofen in Magnaporthe oryzae.

Rice blast, caused by Magnaporthe oryzae, is a devastating fungal disease worldwide. Pydiflumetofen (Pyd) is a new succinate dehydrogenase inhibitor (SDHI) that exhibited anti-fungal activity against M. oryzae. However, control of rice blast by Pyd and risk of resistance to Pyd are not well studied in this pathogen. The baseline sensitivity of 109 M. oryzae strains to Pyd was determined using mycelial growth rate assay, with EC50 values ranging from 0.291 to 2.1313 µg/mL, and an average EC50 value of 1.1005 ± 0.3727 µg/mL. Totally 28 Pyd-resistant (PydR) mutants with 15 genotypes of point mutations in succinate dehydrogenase (SDH) complex were obtained, and the resistance level could be divided into three categories of very high resistance (VHR), high resistance (HR) and moderate resistance (MR) with the resistance factors (RFs) of >1000, 105.74-986.13 and 81.92-99.48, respectively. Molecular docking revealed that all 15 mutations decreased the binding-force score for the affinity between Pyd and target subunits, which further confirmed that these 15 genotypes of point mutations were responsible for the resistance to Pyd in M. oryzae. There was positive cross resistance between Pyd and other SDHIs, such as fluxapyroxad, penflufen or carboxin, while there was no cross-resistance between Pyd and carbendazim, prochloraz or azoxystrobin in M. oryzae, however, PydR mutants with SdhBP198Q, SdhCL66F or SdhCL66R genotype were still sensitive to the other 3 SDHIs, indicating lack of cross resistance. The results of fitness study revealed that the point mutations in MoSdhB/C/D genes might reduce the hyphae growth and sporulation, but could improve the pathogenicity in M. oryzae. Taken together, the risk of resistance to Pyd might be moderate to high, and it should be used as tank-mixtures with other classes of fungicides to delay resistance development when it is used for the control of rice blast in the field.