Cell Membrane Structure Research Articles

Targeted therapies of inflammatory diseases with intracellularly gelated macrophages in mice and rats

Membrane-camouflaged nanomedicines often suffer from reduced efficacy caused by membrane protein disintegration and spatial disorder caused by separation and reassembly of membrane fragments during the coating process. Here we show that intracellularly gelated macrophages (GMs) preserve cell membrane structures, including protein content, integration and fluidity, as well as the membrane lipid order. Consequently, in our testing GMs act as cellular sponges to efficiently neutralize various inflammatory cytokines via receptor-ligand interactions, and serve as immune cell-like carriers to selectively bind inflammatory cells in culture medium, even under a flow condition. In a rat model of collagen-induced arthritis, GMs alleviate the joint injury, and suppress the overall arthritis severity. Upon intravenous injection, GMs efficiently accumulate in the inflammatory lungs of acute pneumonia mice for anti-inflammatory therapy. Conveniently, GMs are amenable to lyophilization and can be stored at ambient temperatures for at least 1 month without loss of integrity and bio-activity. This intracellular gelation technology provides a universal platform for targeted inflammation neutralization treatment.

The antibacterial activity of berberine against Cutibacterium acnes: its therapeutic potential in inflammatory acne.

Cutibacterium acnes (C. acnes) is a major pathogen implicated in the evolution of acne inflammation. Inhibition of C. acnes-induced inflammation is a prospective acne therapy strategy. Berberine (BBR), a safe and effective natural ingredient, has been proven to exhibit powerful antimicrobial and anti-inflammatory properties. However, the antimicrobial effect of BBR against C. acnes and its role in C. acnes-mediated inflammatory acne have not been explored. The objective of this investigation was to assess the antibacterial activity of BBR against C. acnes and its inhibitory effect on the inflammatory response. The results of in vitro experiments showed that BBR exhibited significant inhibition zones against four C. acnes strains, with the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) in the range of 6.25-12.5 μg/mL and 12.5-25 μg/mL, respectively. On the bacterial growth curve, the BBR-treated C. acnes exhibited obvious growth inhibition. Transmission electron microscopy (TEM) images indicated that BBR treatment resulted in significant morphological changes in C. acnes. High-content imaging analysis further confirmed that BBR could effectively inhibit the proliferation of C. acnes. The disruption of cell wall and cell membrane structure by BBR treatment was preliminary confirmed according to the leakage of cellular contents such as potassium (K+), magnesium (Mg2+), and alkaline phosphatase (AKP). Furthermore, we found that BBR could reduce the transcript levels of genes associated with peptidoglycan synthesis (murC, murD, mraY, and murG). Meanwhile, we investigated the modulatory ability of BBR on C. acnes-induced skin inflammation in mice. The results showed that BBR effectively reduced the number of C. acnes colonized in mice's ears, thereby alleviating ear swelling and erythema and significantly decreasing ear thickness and weight. In addition, BBR significantly decreased the levels of pro-inflammatory cytokines IL-6, IL-1β, and TNF-α in auricular tissues. These results suggest that BBR has the potential to treat inflammatory acne induced by C. acnes.

Scopoletin negatively regulates the HOG pathway and exerts antifungal activity against Botrytis cinerea by interfering with infection structures, cell wall, and cell membrane formation

Botrytis cinerea is the causative agent of gray mold, a fungal disease affecting a broad array of food crops and resulting in considerable agricultural and economic losses. Currently, chemical fungicides are the most effective control measure, but this practice is challenged by the growing resistance of pathogens to these fungicides. Scopoletin, a major phytoalexin of tobacco plants, has shown promise as an antifungal treatment. Here, we found that scopoletin was effective against B. cinerea infection of tomato leaves. It inhibited mycelial growth and conidial germination of B. cinerea and disrupted cell wall, cell membrane, and infection structure formation. Transcriptomic analysis identified 3495 differentially expressed genes in response to scopoletin treatment. Interestingly, scopoletin seems to deactivate the HOG pathway of B. cinerea. The growth defect caused by hyperactivation of the pathway, such as iprodione treatment and deletion of BcPtc1, the negative regulator of this pathway, was partly rescued by scopoletin. Moreover, it could downregulate phosphorylation levels of BcSak1 treated with iprodione and NaCl. In addition, the control efficiency of triadimefon was significantly increased by scopoletin. Thus, scopoletin is a promising, naturally derived, and sustainable treatment for gray mold, especially when combined with triadimefon.

Extreme makeover: the incredible cell membrane adaptations of extremophiles to harsh environments.

The existence of life beyond Earth has long captivated humanity, and the study of extremophiles-organisms surviving and thriving in extreme environments-provides crucial insights into this possibility. Extremophiles overcome severe challenges such as enzyme inactivity, protein denaturation, and damage of the cell membrane by adopting several strategies. This feature article focuses on the molecular strategies extremophiles use to maintain the cell membrane's structure and fluidity under external stress. Key strategies include homeoviscous adaptation (HVA), involving the regulation of lipid composition, and osmolyte-mediated adaptation (OMA), where small organic molecules protect the lipid membrane under stress. Proteins also have direct and indirect roles in protecting the lipid membrane. Examining the survival strategies of extremophiles provides scientists with crucial insights into how life can adapt and persist in harsh conditions, shedding light on the origins of life. This article examines HVA and OMA and their mechanisms in maintaining membrane stability, emphasizing our contributions to this field. It also provides a brief overview of the roles of proteins and concludes with recommendations for future research directions.

Teaching Design of History of Biological Sciences Based on STEAM Education Concept—Taking “Exploration of Cell Membrane Composition and Structure” as an Example

Teaching Design of History of Biological Sciences Based on STEAM Education Concept—Taking “Exploration of Cell Membrane Composition and Structure” as an Example

Red cell membrane-coating Prussian blue for combined photothermal and NO gas therapy for nasopharyngeal carcinoma.

Nitric oxide (NO) gas molecules have demonstrated remarkable anti-tumor effects and minimal susceptibility to drug resistance, establishing as a promising modality for effective tumor treatment. However, how to realize its stable and efficient delivery in vivo is still a challenge. In this study, we have developed a heat-responsive biomimetic nano erythrocyte (M/B@R) by loading a NO donor (BNN6) onto mesoporous Prussian blue (M-PB) and subsequently enveloping them with red blood cell membranes. The preserved integrity of the red blood cell membrane (RBCm) structure could ensure its excellent biosafety, prolong its circulation time within the bloodstream and then enhance the accumulation of BNN6 at tumor sites. When M/B@R is stimulated by near-infrared light (NIR-II, 808 nm) irradiation, the nanoparticle could generate significant heat for photothermal therapy (PTT) by the characteristic NIR absorption of M-PB and then NO could also be efficiently released. The generated NO further facilitates the formation of ONOO-, a highly toxic species to tumors, while also alleviating tumor hypoxia. Remarkably, M/B@R, with NIR as the excitation source, induces combined lethality through hyperthermia, DNA damage, and tumor hypoxia relief. This novel combination strategy provides a new avenue for PTT/NO-induced cancer therapy.

Endosome associated trafficking regulator 1 promotes tumor growth and invasion of glioblastoma multiforme via inhibiting TNF signaling pathway.

Endosome associated trafficking regulator 1 (ENTR1) is a novel endosomal protein, which can affect multiple cellular biological behavior by remodeling plasma membrane structures. However, little is known regarding its function and underlying mechanisms in glioblastoma multiforme. Expression profile and clinical signature were obtained from The Public Database of human tumor. Immunohistochemical staining and western blotting assays were used to measure ENTR1 expression level. Human primary GBM tumor cells and human GBM cell lines A172, U87 and U251 were used to clarify the precise role of ENTR1. CCK-8 assays, wound healing and transwell invasion assays were designed to investigate cell viability, invasion and migration of GBM cells, respectively. Underlying molecular mechanisms of ENTR1 were determined via RNA-seq analysis. Tumor formation assay was used to validate the influence of ENTR1 in vivo. Compared with normal brain tissues, ENTR1 was highly expressed in gliomas and correlated with malignant grades of gliomas and poor overall survival time. The proliferation and invasion of GBM cells could be weaken and the sensitivity to temozolomide (TMZ) chemotherapy increased after knocking down ENTR1. Overexpression of ENTR1 could reverse this effect. RNA-seq analysis showed that tumor necrosis factor (TNF) signaling pathway might be a putative regulatory target of ENTR1. Tumor formation assay validated that ENTR1 was a significant factor in tumor growth. Our results indicated that ENTR1 played an important role in cell proliferation, invasion and chemotherapeutic sensitivity of GBM, suggesting that ENTR1 might be a novel prognostic marker and significant therapeutic target for GBM.

New azole derivatives linked to indole/indoline moieties combined with FLC against drug-resistant Candida albicans.

Candida albicans is the most common fungal pathogen associated with human opportunistic infections. Invasive infections caused by C. albicans are becoming increasingly serious. However, with the rising incidence of fungal infection, many fungi are resistant to commonly used drugs. Therefore, there is an urgent need for exploring new anti-fungal drugs that fungi are not resistant to. A series of novel azole derivatives linked to indole/indoline moieties were prepared, and in vitro antifungal activity evaluated. All compounds combined with FLC showed excellent activity against drug-resistant C. albicans with low toxicity. A preliminary mechanistic study indicated that S1 combined with FLC could inhibit the formation of C. albicans biofilms as well as destroy the integrity of cell-membrane structure and mitochondrial function. S1 could be considered a new fungal agent for further study.

2-Bromopalmitate inhibits malignant behaviors of HPSCC cells by hindering the membrane location of Ras protein.

Palmitoylation, which is mediated by protein acyltransferase (PAT) and performs important biological functions, is the only reversible lipid modification in organism. To study the effect of protein palmitoylation on hypopharyngeal squamous cell carcinoma (HPSCC), the expression levels of 23 PATs in tumor tissues of 8 HPSCC patients were determined, and high mRNA and protein levels of DHHC9 and DHHC15 were found. Subsequently, we investigated the effect of 2-bromopalmitate (2BP), a small-molecular inhibitor of protein palmitoylation, on the behavior of Fadu cells in vitro (50 μM) and in nude mouse xenograft models (50 μmol/kg), and found that 2BP suppressed the proliferation, invasion, and migration of Fadu cells without increasing cell apoptosis. Mechanistically, the effect of 2BP on the transduction of BMP, Wnt, Shh, and FGF signaling pathways was tested with qRT-PCR, and its drug target was explored with western blotting and acyl-biotinyl exchange assay. Our results showed that 2BP inhibited the transduction of the FGF/ERK signaling pathway. The palmitoylation level of Ras protein decreased after 2BP treatment, and its distribution in the cell membrane structure was reduced significantly. The findings of this work reveal that protein palmitoylation mediated by DHHC9 and DHHC15 may play important roles in the occurrence and development of HPSCC. 2BP is able to inhibit the malignant biological behaviors of HPSCC cells, possibly via hindering the palmitoylation and membrane location of Ras protein, which might, in turn, offer a low-toxicity anti-cancer drug for targeting the treatment of HPSCC.

Comparative transcriptomes reveal molecular mechanisms of apple blossoms of different tolerance genotypes to chilling injury.

Apple (Malus domestica, Borkh.) is one of the four largest fruits in the world. Freezing damage during the flowering period of apples is one of the main factors leading to the reduction or even extinction of apple production. Molecular breeding of hardy apples is a good solution to these problems. However, the current screening of cold tolerance genes still needs to be resolved. Therefore, in this article, the transcriptome detection and cold tolerance gene screening during the cold adaptation process of apple were studied in order to obtain potential cold-resistant genes. Herein, two high-quality apple tree species (Malus robusta Rehd and M. domestica) were used for cold adaptation experiments and studied under different low-temperature stress conditions (0, -2 and -4°C). The antioxidant levels of two apple flower tissues were tested, and the transcriptome of the flowers after cold culture was tested by next-generation sequencing technology. Antioxidant test results show that the elimination of peroxides in M. robusta Rehd and the adjustment of the expression of antioxidant enzymes promote the cold resistance of this variety of apples. Functional enrichment found that the expression of enzyme activity, cell wall and cell membrane structure, glucose metabolism/gluconeogenesis, and signal transmission are the main biological processes that affect the differences in the cold resistance characteristics of the two apples. In addition, three potential cold-resistant genes AtERF4, RuBisCO activase 1, and an unknown gene (ID: MD09G1075000) were screened. In this study, three potential cold-resistant genes (AtERF4, RuBisCO activase 1, and an unknown gene [ID: MD09G1075000]) and three cold-repressed differential genes (AtDTX29, XTH1, and TLP) were screened.

THE EFFECT OF CRONIC ISOLATED ADMINISTRATION OF CADMIUM CHLORIDE ON THE MORPHOLOGICAL STRUCTURES IN THE WALLS OF SMALL INTESTINE OF PREGNANT FEMALE RATS

In recent years, the anthropopolitical environmental polluntion with heavy metals has become one of the main threats to living organisms, including humans, and economic and technological progress is increasingly resulting in the disruption of natural ecosystems. Heavy metals include more than forty chemical elements of the periodic table, including chromium, cadmium, manganese, mercury, iron, cobalt, nickel, and others. They are often used in industry and are part of herbicides, insecticides, and medicines. In excessive quantities, they can change the structure of proteins, negatively affect metabolism, lead to cellular mutations, disrupt the structure and permeability of cell membranes, and cause malfunctioning of internal organs. Today, it is important to determine the impact of heavy metal compounds on the body in case of their constant (chronic) intake and accumulation in the body.
 The purpose of this study was to determine morphological changes in the structure of the walls in the small intestine of rats subjected to the chronic isolated exposure to cadmium salts in a dose of 2.0 mg/kg (enteral administration).
 The study involved 32 young female Wistar rats, with weights ranging from 180 to 300 g. Female rats with confirmed pregnancies were divided into the following groups: the first group served as the control, and the second group underwent isolated injection of cadmium chloride solution at a dose of 2.0 mg/kg.
 The results of the experimental daily intragastric long-term administration of cadmium chloride showed morphological changes in the structure of the small intestine in rats. The analysis of the data obtained showed that exposure to cadmium chloride in a dose of 2.0 mg/kg leads to a significant thinning of the villi of the small intestine and mucous membrane compared to the control. When exposed to cadmium chloride in the specified dose, the number of goblet cells in the mucous membrane of the small intestine villi increased at both periods of the study, which indicates an increase in the protective function of the small intestinal mucosa against the action of a negative factor. Under the influence of cadmium, the narrowing of the outer and inner diameters of the crypt was also determined that is confirmed by the calculation of the index of the diameter of the small intestine crypt.

Antibacterial Activity Test of Gotu Kola Leaf Extract (Centella asiatica) Against Staphylococcus aureus Bacteria Isolated from Wounds of Diabetes Mellitus Patients

Staphylococcus aureus, a gram-positive bacterium, is the causative agent of diabetic foot. Traditional medicine using plants needs much further research, especially for wound healing in diabetes mellitus patients. This study is an experimental laboratory investigation on the efficacy of Gotu kola (Centella asiatica) leaf extract against wound-isolated Staphylococcus aureus. Gotu kola leaf extract (12.5%, 25%, 50%, 75%, and 100%), cefixime suspension (positive control), and sterile distilled water were tested. The results of the research showed the formation of an inhibitory zone from testing Gotu kola leaf extract against Staphylococcus aureus bacteria, where the average inhibitory zone was at concentrations of 12.5% (7.2 mm), 25% (11 mm), 50% (13.7 mm), 75% (14 .3 mm), and 100% (19.5 mm). The higher the concentration used, the larger the inhibition zone formed. Research shows that Gotu kola leaves' active substances inhibit energy formation, nucleic acid formation, cell membrane permeability, structure and function, and membrane protein lysis and damage.

The anticancer impacts of free and liposomal caffeic acid phenethyl ester (CAPE) on melanoma cell line (A375).

The deadliest type of skin cancer, malignant melanoma, is also the reason for the majority of skin cancer-related deaths. The objective of this article was to investigate the efficiency of free caffeic acid phenethyl ester (CAPE) and liposomal CAPE in inducing apoptosis in melanoma cells (A375) in in vitro. CAPE was loaded into liposomes made up of hydrogenated soybean phosphatidylcholine, cholesterol, and 1,2-distearoyl-sn-glycero-3 phosphoethanolamine-N-[methoxy (polyethylene glycol)-2000],and their physicochemical properties were assessed. (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) test was performed for comparing the cytotoxicity of free CAPE and liposomal CAPE at dosages of 10, 15, 25, 50, 75 and the highest dose of 100 μg/mL for period of 24 and 48 h on A375 cell line to calculate IC50. Apoptosis and necrosis were evaluated in A375 melanoma cancer cells using flow cytometry. Atomic force microscopywas utilized to determine the nanomechanical attributes of the membrane structure of A375 cells. To determine whether there were any effects on apoptosis, the expression of PI3K/AKT1 and BAX/BCL2 genes was analyzed using the real-time polymerase chain reaction technique. According to our results, the maximum amount of drug release from nanoliposomes was determined to be 91% and the encapsulation efficiency of CAPE in liposomes was 85.24%. Also, the release of free CAPE was assessed to be 97%. Compared with liposomal CAPE, free CAPE showed a greater effect on reducing the cancer cell survival after 24 and 48 h. Therefore, IC50 values of A375 cells treated with free and liposomal CAPE were calculated as 47.34 and 63.39 μg/mL for 24 h. After 48 h of incubation of A375 cells with free and liposomal CAPE, IC50 values were determined as 30.55 and 44.83 μg/mL, respectively. The flow cytometry analysis revealed that the apoptosis induced in A375 cancer cells was greater when treated with free CAPE than when treated with liposomal CAPE. The highest nanomechanical changes in the amount of cell adhesion forces, and elastic modulus value were seen in free CAPE. Subsequently, the greatest decrease in PI3K/AKT1 gene expression ratio occurred in free CAPE.

Montmorillonite-based edible coating enhances the postharvest quality of sweetpotato by regulating ROS and membrane lipid metabolism

The quality deterioration of sweetpotatoes easily during postharvest storage owing to their high respiration rate and accumulation of reactive oxygen species (ROS). In this study, an edible coating (MCW) assembled using montmorillonite, chitosan, and whey protein isolate was fabricated to improve the postharvest quality of sweetpotatoes, and the regulatory mechanism of the edible coating treatment on sweetpotato quality has investigated. The results confirmed that edible coating treatment had a positive effect on maintaining the appearance, firmness, colour, and sensory quality of sweetpotatoes, especially in maintaining free water, starch and soluble protein content, inhibiting respiration rate and delaying weight loss of sweetpotatoes stored at 25 °C for 30 d. Meanwhile, this study illuminated the MCW coating regulates ROS metabolism by upregulating superoxide dismutase, ascorbate peroxidase, and glutathione reductase gene expression, resulting in lower O2−. content in postharvest sweetpotato. Furthermore, the relative expression of the genes encoding lipoxygenase, phospholipase C, and phospholipase D was downregulated by the edible coating treatment and contributed to lower enzyme activity, electrolyte leakage and malondialdehyde content, which further reduced the degree of membrane lipid peroxidation and effectively maintained the structure of plasma membrane and then protected the cell integrity of sweetpotato. Collectively, this study provides useful information at the transcriptional level that MCW coating can enhance the post-harvest quality of sweetpotatoes by regulating ROS and membrane lipid metabolism.

The double heterostructure photocatalyst MoS2@ZIF-67/TiO2: Triumphant modification of TiO2 and efficient removal of Karenia mikimotoi

Water eutrophication led to the occurrence of harmful algal blooms (HABs) with the increase of urban sewage and industrial wastewater. As a periodic ecological disaster, it caused serious harm to the ecological environment (including the destruction of the food chain and the death of animals, etc.) and human health. Karenia mikimotoi (K. mikimotoi) was a kind of common algae that caused red tides, and it could produce harmful toxins. Therefore, a composite photocatalyst MoS2@ZIF-67/TiO2 (MZ/T) for the inactivation of K. mikimotoi was synthesized by a simple and easy-to-operate hydrothermal synthesis method. The MoS2@ZIF-67 nanoflowers were attached by the grainy TiO2. The composite photocatalyst MZ/T showed excellent photocatalytic performance, and the inactivation efficiency of MZ/T was up to 97.2 % in 4 h and 99.45 % in 12 h. The composite photocatalyst MZ/T could inactivate algal cells by destroying cell membrane structure, reducing chlorophyll content, soluble protein content. This study would provide a novel photocatalyst for water treatment of HABs.

Protein and lipid expansion microscopy with trypsin and tyramide signal amplification for 3D imaging

Expansion microscopy, whereby the relative positions of biomolecules are physically increased via hydrogel expansion, can be used to reveal ultrafine structures of cells under a conventional microscope. Despite its utility for achieving super-resolution imaging, expansion microscopy suffers a major drawback, namely reduced fluorescence signals caused by excessive proteolysis and swelling effects. This caveat results in a lower photon budget and disfavors fluorescence imaging over a large field of view that can cover an entire expanded cell, especially in 3D. In addition, the complex procedures and specialized reagents of expansion microscopy hinder its popularization. Here, we modify expansion microscopy by deploying trypsin digestion to reduce protein loss and tyramide signal amplification to enhance fluorescence signal for point-scanning-based imaging. We name our new methodology TT-ExM to indicate dual trypsin and tyramide treatments. TT-ExM may be applied for both antibody and lipid staining. TT-ExM displayed enhanced protein retention for endoplasmic reticulum and mitochondrial markers in COS-7 cell cultures. Importantly, TT-ExM-based lipid staining clearly revealed the complex 3D membrane structures in entire expanded cells. Through combined lipid and DNA staining, our TT-ExM methodology highlighted mitochondria by revealing their DNA and membrane structures in cytoplasm, as well as the lipid-rich structures formed via phase separation in nuclei at interphase. We also observed lipid-rich chromosome matrices in the mitotic cells. These high-quality 3D images demonstrate the practicality of TT-ExM. Thus, readily available reagents can be deployed in TT-ExM to significantly enhance fluorescence signals and generate high-quality and ultrafine-resolution images under confocal microscopy.

БИОХИМИЧЕСКАЯ ИНТЕРПРЕТАЦИЯ СИНЕРГЕТИЧЕСКОГО ДЕЙСТВИЯ БИОЛОГИЧЕСКИ АКТИВНЫХ ВЕЩЕСТВ ПО ОТНОШЕНИЮ К ПРОТИВОМИКРОБНЫМ СРЕДСТВАМ МЕТОДАМИ КОМПЬЮТЕРНОЙ ХИМИИ

Due to the widespread resistance of microorganisms to existing drugs, the need for the search and development of new antibacterial forms is extremely high. The use of complexes of natural compounds, characterized by a wide variety, and antibiotics can make it possible to obtain antimicrobial agents of a diverse chemical structure and mechanism of action, and ensure the emergence of new effective medicines.There is a large amount of evidence that biologically active substances (BAS) of plant extracts can improve the work of some antimicrobials, their effect is: the ability to disrupt the structure of the bacterial plasma membrane, causing the formation of pores and leakage of internal contents; changes in electric charge and polarity; increased permeability, change in fluidity and other phenomena responsible for antibacterial activity. Synthesis of antibacterial compounds based on chemical modification of antimicrobial agents by natural complexes is one of the promising methods in the fight against antibiotic resistance. In this work, the synergistic effect of biologically active substances (BAS) of medicinal plants in relation to antimicrobial agents, ceftazidime and fosfomycin was investigated using computer chemistry methods. The variаnt of the effect of BAS on both the antibiotic and penicillin-binding proteins or beta-lactamases as part of a complex with an antibiotic was evaluated, as a result of which protein inhibition, its conformational rearrangement, or a decrease in the required minimum concentration of the antibiotic could occur. Ceftazidime and fosfomycin were chosen as the studied antibacterial drugs. The ligands were 8 molecules (BAS) with antimicrobial properties, such as: allicin, gallic acid, dihydroquercitin, rutin, atropine, tannin, thymol and saponin. 2 proteins from the RCSB Protein Data Bank database belonging to two different classes of enzymes were selected as binding models. At the first stage, the molecules of the studied substances were optimized in a small approximation HF/3-21+G and the thermodynamic problem was calculated. The second stage was a configuration search, after which molecular docking took place, binding of the studied substances (ligands) with protein molecules in the AutoDock 4.2.6 program. As a result, it was possible to obtain several binding sites, the probability of which would be the greatest.

INTERAKCJA POMIĘDZY INTENSYWNOŚCIĄ ŚWIATŁA A STRESEM SUSZY I ICH WPŁYW NA WZROST SIEWEK PSZENICY

In this paper, wheat seedlings were exposed to different levels of photon flux density (PFD) and drought stress. Seedlings of the wheat cv. Goplana were cultivated in controlled conditions in a miniphytotrone and exposed to three different photosynthetic photon flux densities (400, 800, and 1200 μmol⋅m−2⋅s−1) and drought stress (a water potential of −0.6 MPa). The Hoagland’s solution-treat- ed seedlings served as a control. The fresh and dry matter of the overground parts and roots, rela- tive chlorophyll concentration, electrical conductivity and chlorophyll fluorescence parameters were measured. Drought stress decreased the biomass of wheat seedlings, cv. Goplana. Higher intensities of photosynthetically active irradiation stimulated biomass growth both under control conditions and under drought stress. Drought and higher PFD intensity resulted in a decrease in chlorophyll content. Only the highest light intensity, together with drought stress, negatively affected the structure of cell membranes, increasing their permeability. Both of the applied stress factors did not cause significant changes in the values of the determined parameters of chlorophyll fluorescence in the leaves of wheat seedlings. These results suggest that the increase in light intensity has a mobilising effect on the plant, stimulating the development of biomass both under control conditions and under drought stress. No changes in the values of chlorophyll fluorescence parameters under the influence of different light intensities and drought stress may indicate that there were no significant disturbances in the course of the light phase of photosynthesis in the leaves of the tested seedlings.

Antifungal activity and mechanism of palmarosa essential oil against pathogen Botrytis cinerea in the postharvest onions.

Botrytis cinerea is a pathogenic fungus that infests multiple crops, which causes a severe decrease in yield and generates substantial losses in the economy. Palmarosa essential oil (PEO) is a primary aromatic compound extracted from palmarosa that is commonly used for scent, medicine, and flavoring foods due to its diverse bioactive properties. In this study, we explored the antifungal activity and the main mechanism of action of PEO against B. cinerea. In addition, the components and control effects of PEO were also studied. The antifungal assay was tested using the mycelial growth rate method and colony morphology. The constituents of PEO were identified according to gas chromatography/mass spectrometry (GC-MS). The main mechanism of action of PEO was evaluated by measuring representative indicators, which consist of cell contents leakage, excess reactive oxygen species (ROS), and other related indicators. The results indicated that at a concentration of 0.60ml l-1, PEO exhibits strong antifungal activity against B. cinerea. The PEO mainly included 13 compounds, of which citronellol (44.67%), benzyl benzoate (14.66%), and acetyl cedrene (9.63%) might be the main antifungal ingredients. The study elucidated the main mechanism of action of PEO against B. cinerea, which involved the disruption of cell membrane structure, resulting in altered the cell membrane permeability, leakage of cell contents, and accumulation of excess ROS. PEO is a satisfactory biological control agent that inhibits B. cinerea in postharvest onions. PEO (0.60ml l-1) exhibited strong antifungal activity by disrupting the cell membrane structure, altering cell membrane permeability, leading to the cell contents leakage, accumulation of excess ROS and increased level of Malondialdehyde (MDA) compared to the control group.

Multi‐omics approach reveals disturbances in brain phosphatidylcholine metabolism in Alzheimer’s Disease

AbstractBackgroundLipid dysregulation is implicated in Alzheimer’s disease (AD) pathology, given its involvement in amyloid β processing, myelination, and cell membrane structure. Studies have demonstrated increased phosphatidylcholine (PC) hydrolysis in the brains of AD individuals, but the connections between AD and PC metabolism are not fully understood.MethodTo investigate the alterations in PC metabolism in AD, we analyzed publicly available transcriptomic, metabolomic, and lipidomic data from the ROSMAP study, which included dorsolateral prefrontal cortex (DLPFC) tissue and serum samples. DLPFC and serum samples were classified based on clinical consensus diagnosis of cognitive status at the time of death and the last valid clinical diagnosis, respectively. Concentration differences were determined with a linear model using the Limma R package.ResultAccording to the lipidomic results, the concentration of total PC‐containing glycerophospholipid was significantly decreased in AD DLPFC samples (P < 0.05). Specifically, diacyl‐PC and acyl‐alkyl‐PC, the two most abundant subclasses, were significantly decreased in the brains of AD patients (P < 0.05). The concentration of the PC breakdown product, glycerophosphocholine (GPC), was increased in AD patient brains (P‐value < 0.05). However, GPC phosphodiesterase 1 (GPCPD1), the enzyme that further hydrolyzes GPC to free choline, was downregulated and choline abundance was reduced in AD DLPFC samples (P < 0.05). The expression of phosphatidylethanolamine N‐methyltransferase (PEMT), which converts PE to PC, was reduced as was the abundance of PEMT products (PC 18:2/20:4 and PC 18:0/20:4, P < 0.05). These alterations in the brain were not observed in the serum.ConclusionThese results indicate that PC metabolism is disturbed in the DLPFC of AD patients, with evidence of increased PC breakdown and reduced GPC hydrolysis as well as reduced conversion of PE to PC in AD brains. However, these changes in the brain are not reflected in serum. Further studies are needed to better understand changes in phospholipid metabolism in the brains of AD patients.