Enzyme In Biosynthesis Research Articles

Chloroplast protein StFC-II was manipulated by a Phytophthora effector to enhance host susceptibility.

Oomycete secretes a range of RxLR effectors into host cells to manipulate plant immunity by targeting proteins from several organelles. In this study, we report that chloroplast protein StFC-II is hijacked by a pathogen effector to enhance susceptibility. Phytophthora infestans RxLR effector Pi22922 is activated during the early stages of P. infestans colonization. Stable overexpression of Pi22922 in plants suppresses flg22-triggered reactive oxygen species (ROS) burst and enhances leaf colonization by P. infestans. A potato ferrochelatase 2 (FC-II, a nuclear-encoded chloroplast-targeted protein), a key enzyme for heme biosynthesis in chloroplast, was identified as a target of Pi22922 in the cytoplasm. The pathogenicity of Pi22922 in plants is partially dependent on FC-II. Overexpression of StFC-II decreases resistance of potato and Nicotiana benthamiana against P. infestans, and silencing of NbFC-II in N. benthamiana reduces P. infestans colonization. Overexpression of StFC-II increases heme content and reduces chlorophyll content and photosynthetic efficiency in potato leaves. Moreover, ROS accumulation both in chloroplast and cytoplasm is attenuated and defense-related genes are down-regulated in StFC-II overexpression transgenic potato and N. benthamiana leaves. Pi22922 inhibits E3 ubiquitin ligase StCHIP-mediated StFC-II degradation in the cytoplasm and promotes its accumulation in chloroplasts. In summary, this study characterizes a new mechanism that an oomycete RxLR effector suppresses host defenses by promoting StFC-II accumulation in chloroplasts, thereby compromising the host immunity and promoting susceptibility.

FOXA3 regulates cholesterol metabolism to compensate for low uptake during the progression of lung adenocarcinoma.

Cholesterol metabolism is vital for multiple cancer progression, while how cholesterol affects lung, a low-cholesterol tissue, for cancer metastasis and the underlying mechanism remain unclear. In this study, we found that metastatic lung adenocarcinoma cells acquire cellular dehydrocholesterol and cholesterol by endogenous cholesterol biosynthesis, instead of uptake upon cholesterol treatment. Besides, we demonstrated that exogenous cholesterol functions as signaling molecule to induce FOXA3, a key transcription factor for lipid metabolism via GLI2. Subsequently, ChIP-seq analysis and molecular studies revealed that FOXA3 transcriptionally activated Hmgcs1, an essential enzyme of cholesterol biosynthesis, to induce endogenous dehydrocholesterol and cholesterol level for membrane composition change and cell migration. Conversely, FOXA3 knockdown or knockout blocked cholesterol biosynthesis and lung adenocarcinoma metastasis in mice. In addition, the potent FOXA3 inhibitor magnolol suppressed metastatic gene programs in lung adenocarcinoma patient-derived organoids (PDOs). Altogether, our findings shed light onto unique cholesterol metabolism and FOXA3 contribution to lung adenocarcinoma metastasis.

ATP and Formyl Peptides Facilitate Chemoattractant Leukotriene-B4 Synthesis and Drive Calcium Fluxes, Which May Contribute to Neutrophil Swarming at Sites of Cell Damage and Pathogens Invasion.

Here, we demonstrate that human neutrophil interaction with the bacterium Salmonella typhimurium fuels leukotriene B4 synthesis induced by the chemoattractant fMLP. In this work, we found that extracellular ATP (eATP), the amount of which increases sharply during tissue damage, can effectively regulate fMLP-induced leukotriene B4 synthesis. The vector of influence strongly depends on the particular stage of sequential stimulation of neutrophils by bacteria and on the stage at which fMLP purinergic signaling occurs. Activation of 5-lipoxygenase (5-LOX), key enzyme of leukotriene biosynthesis, depends on an increase in the cytosolic concentration of Ca2+. We demonstrate that eATP treatment prior to fMLP, by markedly reducing the amplitude of the fMLP-induced Ca2+ transient jump, inhibits leukotriene synthesis. At the same time, when added with or shortly after fMLP, eATP effectively potentiates arachidonic acid metabolism, including by Ca2+ fluxes stimulation. Flufenamic acid, glibenclamide, and calmodulin antagonist R24571, all of which block calcium signaling in different ways, all suppressed 5-LOX product synthesis in our experimental model, indicating the dominance of calcium-mediated mechanisms in eATP regulatory potential. Investigation into the adhesive properties of neutrophils revealed the formation of cell clusters when adding fMLP to neutrophils exposed to the bacterium Salmonella typhimurium. eATP added simultaneously with fMLP supported neutrophil polarization and clustering. A cell-derived chemoattractant such as leukotriene B4 plays a crucial role in the recruitment of additional neutrophils to the foci of tissue damage or pathogen invasion, and eATP, through the dynamics of changes in [Ca2+]i, plays an important decisive role in fMLP-induced leukotrienes synthesis during neutrophil interactions with the bacterium Salmonella typhimurium.

Combined Pretreatment with Bioequivalent Doses of Plant Growth Regulators Alleviates Dehydration Stress in Lactuca sativa

Plant hormones regulate adaptive responses to various biotic and abiotic stress factors. Applied exogenously, they trigger the natural plant defense mechanisms, a feature that could be implemented in strategies for supporting crop resilience. The potential of the exogenous cytokinin-like acting compound (kinetin), the auxin analogue 1-naphtyl acetic acid (NAA), abscisic acid (ABA) and the ethyleneprecursor 1-aminocyclopropane-1-carboxylic acid (ACC) to mitigate dehydration was tested on Lactuca sativa (lettuce) grown on 12% polyethylene glycol (PEG). Priming with different blends containing these plant growth regulators (PGRs) applied in bioequivalent concentrations was evaluated through biometric measurements and biochemical analyses. The combined treatment with the four compounds exhibited the best dehydration protective effect. The antioxidative enzyme profiling of the PGR-primed individuals revealed increased superoxide dismutase (SOD), catalase and peroxidase activity in the leaves. Immunodetection of higher levels of the rate-limiting enzyme for proline biosynthesis (delta-pyroline-5-carboxylate synthase) in the primed plants coincided with a significantly higher content of the amino acid measured in the leaves. These plants also accumulated particular dehydrin types, which may have contributed to the observed stress-relieving effect. The four-component mix applied by spraying or through the roots exerted similar stress-mitigating properties on soil-grown lettuce subjected to moderate drought.

The flavohemoglobin Yhb1 is a new interacting partner of the heme transporter Str3.

Nitric oxide (˙NO) is a free radical that induces nitrosative stress, which can jeopardize cell viability. Yeasts have evolved diverse detoxification mechanisms to effectively counteract ˙NO-mediated cytotoxicity. One mechanism relies on the flavohemoglobin Yhb1, whereas a second one requires the S-nitrosoglutathione reductase Fmd2. To investigate heme-dependent activation of Yhb1 in response to ˙NO, we use hem1Δ-derivative Schizosaccharomyces pombe strains lacking the initial enzyme in heme biosynthesis, forcing cells to assimilate heme from external sources. Under these conditions, yhb1+ mRNA levels are repressed in the presence of iron through a mechanism involving the GATA-type transcriptional repressor Fep1. In contrast, when iron levels are low, the transcription of yhb1+ is derepressed and further induced in the presence of the ˙NO donor DETANONOate. Cells lacking Yhb1 or expressing inactive forms of Yhb1 fail to grow in a hemin-dependent manner when exposed to DETANONOate. Similarly, the loss of function of the heme transporter Str3 phenocopies the effects of Yhb1 disruption by causing hypersensitivity to DETANONOate under hemin-dependent culture conditions. Coimmunoprecipitation and bimolecular fluorescence complementation assays demonstrate the interaction between Yhb1 and the heme transporter Str3. Collectively, our findings unveil a novel pathway for activating Yhb1, fortifying yeast cells against nitrosative stress.

Unraveling the nexus of NAD+ metabolism and diabetic kidney disease: insights from murine models and human data.

Nicotinamide adenine dinucleotide (NAD+) is a critical coenzyme involved in kidney disease, yet its regulation in diabetic kidney disease (DKD) remains inadequately understood. Therefore, we investigated the changes of NAD+ levels in DKD and the underlying mechanism. Alternations of NAD+ levels and its biosynthesis enzymes were detected in kidneys from streptozotocin-induced diabetic mouse model by real-time PCR and immunoblot. The distribution of NAD+ de novo synthetic enzymes was explored via immunohistochemical study. NAD+ de novo synthetic metabolite was measured by LC-MS. Human data from NephroSeq were analyzed to verify our findings. The study showed that NAD+ levels were decreased in diabetic kidneys. Both mRNA and protein levels of kynurenine 3-monooxygenase (KMO) in NAD+ de novo synthesis pathway were decreased, while NAD+ synthetic enzymes in salvage pathway and NAD+ consuming enzymes remained unchanged. Further analysis of human data suggested KMO, primarily expressed in the proximal tubules shown by our immunohistochemical staining, was consistently downregulated in human diabetic kidneys. Our study demonstrated KMO of NAD+ de novo synthesis pathway was decreased in diabetic kidney and might be responsible for NAD+ reduction in diabetic kidneys, offering valuable insights into complex regulatory mechanisms of NAD+ in DKD.

Sodium Metabisulfite Inhibits Acanthamoeba Trophozoite Growth through Thiamine Depletion.

Acanthamoeba keratitis (AK) is a severe infection of the cornea. Prevention and treatment are difficult due to the inefficacy of currently available compounds. The impact of many commonly used compounds for routine examinations of Acanthamoeba is unexplored but might offer insight useful in combatting AK. In this study, we demonstrate that sodium metabisulfite, a common preservation constituent of eye care solutions, was found to be active against Acanthamoeba trophozoites at concentrations lower than that commonly found in eye drops (IC50 0.03 mg/mL). We demonstrate that sodium metabisulfite depletes thiamine from growth medium and that Acanthamoeba is a thiamine auxotroph, requiring thiamine salvage for growth. The inhibitory effects of sodium metabisulfite can be overcome by thiamine supplementation. These results are consistent with the lack of key enzymes for thiamine biosynthesis in the genome of Acanthamoeba, an area which might prove exploitable using new or existing compounds. Indeed, this study highlights sodium metabisulfite as a useful inhibitor of Acanthamoeba castellanii trophozoites in vitro and that it acts, at least in part, by limiting available thiamine.

A paREDOX in the control of cholesterol biosynthesis: Does the NADPH sensor and E3 ubiquitin ligase MARCHF6 protect mammalian cells during oxidative stress by controlling sterol biosynthesis?

Sterols and the reductant nicotinamide adenine dinucleotide phosphate (NADPH), essential for eukaryotic life, arose because of, and as an adaptation to, rising levels of molecular oxygen (O2). Hence, the NADPH and O2-intensive process of sterol biosynthesis is inextricably linked to redox status. In mammals, cholesterol biosynthesis is exquisitely regulated post-translationally by multiple E3 ubiquitin ligases, with membrane associated Really Interesting New Gene (RING) C3HC4 finger 6 (MARCHF6) degrading at least six enzymes in the pathway. Intriguingly, all these MARCHF6-dependent enzymes require NADPH. Moreover, MARCHF6 is activated by NADPH, although what this means for control of cholesterol synthesis is unclear. Indeed, this presents a paradox for how NADPH regulates this vital pathway, since NADPH is a cofactor in cholesterol biosynthesis and yet, low levels of NADPH should spare cholesterol biosynthesis enzymes targeted by MARCHF6 by reducing its activity. We speculate MARCHF6 helps mammalian cells adapt to oxidative stress (signified by low NADPH levels) by reducing degradation of cholesterogenic enzymes, thereby maintaining synthesis of protective cholesterol.

Isolation and Characterization of Insecticidal Cyclotides from Viola communis.

Cyclotides are cysteine-rich plant-derived peptides composed of 28-37 amino acids with a head-to-tail cyclic backbone and a knotted arrangement of three conserved disulfide bonds. Their beneficial biophysical properties make them promising molecules for pharmaceutical and agricultural applications. The Violaceae plant family is the major cyclotide-producing family, and to date, every examined plant from this family has been found to contain cyclotides. The presence of cyclotides in Viola communis was inferred by mass spectroscopy previously, but their sequences and properties had yet to be explored. In this study, the occurrence of cyclotides in this plant was investigated using proteomics and transcriptomics. Twenty cyclotides were identified at the peptide level, including two new members from the bracelet (Vcom1) and Möbius (Vcom2) subfamilies. Structural analysis of these newly identified peptides demonstrated a similar fold compared with cyclotides from the same respective subfamilies. Biological assays of Vcom1 and Vcom2 revealed them to be cytotoxic to Sf9 insect cell lines, with Vcom1 demonstrating higher potency than Vcom2. The results suggest that they could be further explored as insecticidal agents and confirm earlier general findings that bracelet cyclotides have more potent insecticidal activity than their Möbius relatives. Seven new cyclotide-like sequences were observed in the transcriptome of V. communis, highlighting the Violaceae as a rich source for new cyclotides with potential insecticidal activity. An analysis of sequences flanking the cyclotide domain in the various precursors from V. communis and other Violaceae plants revealed new insights into cyclotide processing and suggested the possibility of two alternative classes of N-terminal processing enzymes for cyclotide biosynthesis.

The homeodomain of the <i>Raphanus sativus</i> WOX4 binds to the promoter of the <i>LOG3</i> cytokinin biosynthesis gene

BACKGROUND: The WOX4 transcription factor plays a crucial role in maintaining the organisation of cambium meristem during secondary growth, but its direct targets are unknown. AIM: The aim of our work were to study the effect of WOX4 overexpression on the root development and gene expression in radish (Raphanus sativus L.), a root crop related to Arabidopsis thaliana, and to search for direct targets of the WOX4 in radish. MATERIALS AND METHODS: Radish line 19 of the St. Petersburg State University radish genetic collection was used. Plants were grown on Murashige–Skoog medium and then in soil at 23оС and 16 h of daylight. Total DNA was extracted from radish seedlings using the CTAB method. The PCR-amplified full-length RsWOX4-2 gene, gene fragments or homeobox sequence were cloned into the vectors for overexpression (pB7WG2D), RNA interference (pH7GWIWG2) and yeast one-hybrid assay (pDEST22), respectively, using the Gateway system. The vectors for overexpression and RNA interference of RsWOX4-2 were transformed into Escherichia coli DH10B and then into Agrobacteium rhizogenes Arqua chemically competent cells. Radish seedlings were transformed with A. rhizogenes containing vectors for overexpression and RNA interference of RsWOX4-2, and GUS-overexpressing A. rhizogenes was used as a control. Total RNA from transgenic radish roots was extracted with Trizol reagent. RNA reverse transcription was performed using dT-18 primers and RevertAid reverse transcriptase. qPCR was performed using the Eva Green reagent kit on a CFX96 thermocycler with fluorescence detection system. Results were processed using the 2–ΔΔCT method. Yeast transformation was performed using the competent Saccharomyces cerevisiae cells of Y2H Gold strain. For the yeast one-hybrid assay, the obtained yeast colonies transformed with plasmids containing TF homeodomain sequence and promoter regions of genes were grown on DDO and TDO selective media with different concentrations of 3-amino-1,2,4-triazole. Statistical processing based on Student’s t-test and graphing were performed using the ggplot2 package for the R programming language (v.4.0.2). RESULTS: Overexpression of the RsWOX4-2 gene affects the structure of the radish root stele and alters the number of vessels and cambium cells. Overexpression and RNA interference of the RsWOX4-2 causes changes in the expression levels of putative target genes with the WOX family transcription factor conserved binding sites in their promoters. Using the yeast one-hybrid assay, we have shown that the DNA-binding homeodomain of RsWOX4-2 interacts with the TAATCC site in the promoter of the RsLOG3 gene, which encodes the enzyme for cytokinin biosynthesis. CONCLUSIONS: We have demonstrated the effect of RsWOX4-2 overexpression on radish root stele and gene expression and identified the RsLOG3 as the putative direct target of the WOX4 transcription factor in radish.

Exploring the Mechanisms of Yuanhu Zhitong Oral Liquid for Primary Dysmenorrhea through Network Pharmacology, Molecular Docking, and Molecular Dynamics Simulation

Objective: Primary dysmenorrhea (PD) is a prevalent gynecological disorder. Yuanhu Zhitong oral liquid (YHZT) presents a promising alternative treatment for PD. However, the mechanisms underlying its efficacy remain unclear. This study aims to investigate the potential targets and mechanisms of action of YHZT in treating PD using network pharmacology, molecular docking, and molecular dynamics simulations. Methods: Potential compounds from YHZT were obtained from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) and the Traditional Chinese Medicine Information Database (TCMID). The relevant targets of these compounds were identified using the similarity ensemble approach (SEA) and the Swiss Target Prediction database. PD-related targets were retrieved from the Genecards, DrugBank, and Disgenet databases. ClusterProfiler was utilized for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. The compound-target-pathway (CTP) network was constructed to facilitate the identification of key compounds, core targets, and signaling pathways. Finally, molecular docking and molecular dynamics simulations were performed to evaluate the interactions between the targets and compounds. Results: A total of 153 putative compounds and 129 targets of YHZT were identified. Network topology analysis revealed eight core targets and six key compounds. The effects of YHZT were mediated by genes associated with hormone and steroid metabolism, as well as pathways involved in steroid hormone biosynthesis and cytochrome P450 enzymes. Docking results showed free-binding energies ranging from -6.06 to -10.85 kcal/mol, indicating strong binding affinity between the compounds and targets. Molecular dynamics simulation results further confirmed the stability of these interactions. Conclusion: This study demonstrates that YHZT treats PD by suppressing inflammatory reactions and modulating hormone and cytochrome P450 concentrations. Key compounds such as ferulic acid, (R)-canadine, (S)-canadine, canadine, and asristolone are implicated in this process. These findings offer insights into the mechanisms underlying the action of YHZT and provide a foundation for further research in this area.

Oleanolic acid inhibits cholesterol synthesis by suppressing the expression and enzymatic activity of HMGCR

ABSTRACT This study investigated the impact of Oleanolic Acid (OA) on cholesterol metabolism and. MTT assays demonstrated that OA had no cytotoxic effects on HepG2 cells at concentrations below 20 μM. Subsequent experiments focused on 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGCR), a key enzyme in cholesterol biosynthesis. OA significantly reduced HMGCR protein expression without affecting other enzymes. Further investigations revealed that OA reduced the protein and mRNA expression of HMGCR and its upstream regulator Sterol regulatory element binding protein-2 (SREBP-2) in HepG2 cells. OA activated Adenosine 5’-monophosphate (AMP)-activated protein kinase (AMPK), enhancing HMGCR phosphorylation and inhibiting its activity. Molecular docking experiments suggested that OA could suppress HMGCR enzymatic activity through hydrophobic interactions, reducing catalytic efficiency. Overall, OA downregulated HMGCR expression and activity, leading to decreased cholesterol synthesis. These findings highlight OA’s regulatory role in cholesterol metabolism and its potential for improving atherosclerosis (AS), supporting its application in functional food development.

An integrated multi-omics approach reveals polymethoxylated flavonoid biosynthesis in Citrus reticulata cv. Chachiensis

Citrus reticulata cv. Chachiensis (CRC) is an important medicinal plant, its dried mature peels named “Guangchenpi”, has been used as a traditional Chinese medicine to treat cough, indigestion, and lung diseases for several hundred years. However, the biosynthesis of the crucial natural products polymethoxylated flavonoids (PMFs) in CRC remains unclear. Here, we report a chromosome-scale genome assembly of CRC with the size of 314.96 Mb and a contig N50 of 16.22 Mb. Using multi-omics resources, we discover a putative caffeic acid O-methyltransferase (CcOMT1) that can transfer a methyl group to the 3-hydroxyl of natsudaidain to form 3,5,6,7,8,3’,4’-heptamethoxyflavone (HPMF). Based on transient overexpression and virus-induced gene silencing experiments, we propose that CcOMT1 is a candidate enzyme in HPMF biosynthesis. In addition, a potential gene regulatory network associated with PMF biosynthesis is identified. This study provides insights into PMF biosynthesis and may assist future research on mining genes for the biosynthesis of plant-based medicines.

Crosstalk in proline biosynthesis regulates proline augmentation and resilience to salt stress in Panicum miliaceum L.

The development and productivity of most agricultural plants can be adversely affected by the presence of salts in soil. It is vital in these situations to increase agricultural yield, especially in barren soil, by developing plants that can endure and thrive in salty environment. For reducing the detrimental salt-induced effects, plants must actively control osmotic balance by accumulating suitable solutes like proline, polyols, and glycine betaine and by activating specific stress-responsive genes and enzymes within their cells. Proline is an important osmolyte which build up endogenously in plants in response to stressful situations and its accumulation is dependent on type of species and severity of stress. Although proline biosynthesis genes and enzymes have been extensively studied, but the preferred substrate in this process is yet not clear. In present study, we aimed to elucidate the preferred pathway of proline biosynthesis and the effect on physiological parameters under salt and Se application in proso millet. It was found that salt stress negatively impacted these parameters, while as the addition of Se improved these parameters. In comparison to control 150 mM NaCl treatment led to a reduction of upto 38.6% in FW and 18.91% in DW, whereas 200 mM NaCl led to reduction of upto 52.29% in FW and 18.91% in DW. The osmolytes, total soluble sugars (TSS), glycine betaine (GB) and total proline content (TPC) increased under salt stress by 53.7%, 2.14% and 113.79% at 150 mM NaCl and 54.89%, 0.53% and 87.1% at 200 mM NaCl. But, the application of Se significantly improved the above parameters. It was observed that the low level of Se (1 µM) had a role in enhancing the activity of P5CS, P5CR, and OAT enzymes while decreasing the activity of ProDH and P5CDH enzymes. It was found that genes responsible for proline biosynthesis were expressed efficiently in response to salt stress which further increased with Se application. During salt stress proline biosynthesis (PmP5CS, PmP5CR and PmOAT) genes were up-regulated which improved further with Se treatment. While as, the proline degrading (PmP5CDH and PmProDH) genes were down-regulated at both salt and se treatments. Overall, the Se treatment appeared to be beneficial for modulating the plant responses by providing tolerance.

Structural basis of chorismate isomerization by Arabidopsis ISOCHORISMATE SYNTHASE1.

Salicylic acid (SA) plays a crucial role in plant defense against biotrophic and semibiotrophic pathogens. In Arabidopsis (Arabidopsis thaliana), isochorismate synthase 1 (AtICS1) is a key enzyme for the pathogen-induced biosynthesis of SA via catalytic conversion of chorismate into isochorismate, an essential precursor for SA synthesis. Despite the extensive knowledge of ICS1-related menaquinone, siderophore, and tryptophan (MST) enzymes in bacteria, the structural mechanisms for substrate binding and catalysis in plant isochorismate synthase (ICS) enzymes are unknown. This study reveals that plant ICS enzymes catalyze the isomerization of chorismate through a magnesium-dependent mechanism, with AtICS1 exhibiting the most substantial catalytic activity. Additionally, we present high-resolution crystal structures of apo AtICS1 and its complex with chorismate, offering detailed insights into the mechanisms of substrate recognition and catalysis. Importantly, our investigation indicates the existence of a potential substrate entrance channel and a gating mechanism regulating substrate into the catalytic site. Structural comparisons of AtICS1 with MST enzymes suggest a shared structural framework with conserved gating and catalytic mechanisms. This work provides valuable insights into the structural and regulatory mechanisms governing substrate delivery and catalysis in AtICS1, as well as other plant ICS enzymes.

Genomic insights into Streptomyces hygroscopicus subsp. hygroscopicus SRF1: a potential biocontrol agent against fusarium wilt with plant growth-promoting abilities in tomatoes

ABSTRACT Streptomyces sp. isolate SRF1 has previously demonstrated promising results in controlling various plant fungi under in vitro conditions. However, further exploration of its genome and its efficacy in disease control and plant growth promotion under in vivo conditions is warranted. This study aimed to utilise whole genome sequencing (WGS) to classify Streptomyces sp. isolate SRF1 at the species level and predict genes associated with antagonistic ability and plant growth promotion, thereby assessing its potential as a biocontrol agent against fusarium wilt and a promoter of plant growth. WGS was employed to elucidate the taxonomic classification of isolate SRF1 and predict genes involved in disease suppression and plant growth promotion. In vitro assays were conducted to evaluate its antagonistic activity against Fusarium oxysporum f. sp. lycopersici (Fol) and its production of cellulase, amylase, indole-3-acetic acid (IAA), and siderophores. Pot experiments were carried out using SRF1 cell suspension and culture filtrate to assess its efficacy against Fol and its impact on tomato growth. Real-time PCR analysis was performed to correlate gene expression levels with observed activities. The results showed that isolate SRF1 was classified as S. hygroscopicus subsp. hygroscopicus and demonstrated antagonism against Fol. Furthermore, WGS revealed genes or gene clusters associated with disease control, including those encoding antifungal agents such as butyrolactol A, nigericin, and hygromycin A. Additionally, genes responsible for auxin biosynthesis, siderophore production, and carbohydrate-digesting enzymes such as chitinase, cellulase, and amylase were identified, suggesting potential roles in disease suppression and plant growth promotion.

Docking of T6361 Analogues as Potential Inhibitors of E.coli MurA Followed by ADME-Toxicity Study.

Developing more potent antibacterial agents is one of the most important tasks of scientists in the health field due to the problem of antibiotic resistance. Among the antibiotic targets, we mention MurA (UDP-N-Acetylglucosamine Enolpyruvyl Transferase), which is a key enzyme of peptidoglycan biosynthesis of the bacterial cell wall. Our objective was to search for new inhibitors of the bacterial enzyme MurA by docking the analogues of its inhibitor T6361, a derivative of 5-sulfonoxy-anthranilic acid. 990 analogues of T6361 were docked in the first binding site of E.coli MurA (open form) using the FlexX program, and the ADME-Toxicity profile of the best ones was evaluated by SwissADME and PreADMET web servers. . Docking results revealed two T6361 analogues to provide better energy scores than T6361, and have similar interactions with the binding site of E.coli MurA namely,3-{[2-(piperidine-1-carbonyl) phenyl]sulfamoyl}benzoic acid and 3-{[2-(pyrrolidine-1 carbonyl)phenyl]sulfamoyl}benzoic acid. Moreover, the two molecules were found to possess good pharmacokinetics and low toxicity. We propose two analogues of T6361 as new potential inhibitors of MurA enzyme. Their good ADME-Toxicity profile qualifies them to reach in vitro and in vivo assays as future lead molecules.

Tetrahydrobiopterin metabolism attenuates ROS generation and radiosensitivity through LDHA S-nitrosylation: novel insight into radiogenic lung injury

Genotoxic therapy triggers reactive oxygen species (ROS) production and oxidative tissue injury. S-nitrosylation is a selective and reversible posttranslational modification of protein thiols by nitric oxide (NO), and 5,6,7,8-tetrahydrobiopterin (BH4) is an essential cofactor for NO synthesis. However, the mechanism by which BH4 affects protein S-nitrosylation and ROS generation has not been determined. Here, we showed that ionizing radiation disrupted the structural integrity of BH4 and downregulated GTP cyclohydrolase I (GCH1), which is the rate-limiting enzyme in BH4 biosynthesis, resulting in deficiency in overall protein S-nitrosylation. GCH1-mediated BH4 synthesis significantly reduced radiation-induced ROS production and fueled the global protein S-nitrosylation that was disrupted by radiation. Likewise, GCH1 overexpression or the administration of exogenous BH4 protected against radiation-induced oxidative injury in vitro and in vivo. Conditional pulmonary Gch1 knockout in mice (Gch1fl/fl; Sftpa1-Cre+/− mice) aggravated lung injury following irradiation, whereas Gch1 knock-in mice (Gch1lsl/lsl; Sftpa1-Cre+/− mice) exhibited attenuated radiation-induced pulmonary toxicity. Mechanistically, lactate dehydrogenase (LDHA) mediated ROS generation downstream of the BH4/NO axis, as determined by iodoacetyl tandem mass tag (iodoTMT)-based protein quantification. Notably, S-nitrosylation of LDHA at Cys163 and Cys293 was regulated by BH4 availability and could restrict ROS generation. The loss of S-nitrosylation in LDHA after irradiation increased radiosensitivity. Overall, the results of the present study showed that GCH1-mediated BH4 biosynthesis played a key role in the ROS cascade and radiosensitivity through LDHA S-nitrosylation, identifying novel therapeutic strategies for the treatment of radiation-induced lung injury.

High Salt Diet Regulates Intrarenal Sex Steroid Biosynthesis Pathway in a Sex-Specific Manner

Hypertension is more prevalent in men than age-matched pre-menopausal women. Sodium (Na+) homeostasis plays a major role in the control of blood pressure. Renal medullary estrogenic signaling promotes Na+ excretion in female, but not male Sprague Dawley (SD) rats implicating estrogen as a potential female-specific natriuretic factor. Recently we showed that the components of estrogen biosynthesis pathway are expressed in rat kidney suggesting the kidneys can produce estrogen locally to invoke this natriuretic response. It is unknown how dietary Na+ impacts biosynthesis of sex hormones. We hypothesize that a high salt (HS) diet enhances intrarenal estrogen biosynthesis pathway, and this enhancement is more pronounced in females compared to males. To test this hypothesis, we harvested the renal cortex from 14 week old male and female SD rats maintained on either a normal salt (NS 0.3% NaCl) or HS (4% NaCl) diet for 5 days. Given that cholesterol is the main precursor of steroid hormones, we measured the mRNA expression of HMG-CoA reductase (HMGCR), the key enzyme for cholesterol synthesis; and the steroidogenic acute regulatory protein (StAR), which transports cholesterol into the mitochondria for steroid commitment. We also assessed the mRNA expression of steroid 5α reductase (SRD5A), which converts testosterone to the non-aromatizable androgen, dihydrotestosterone. Further, we assessed aromatase, the key enzyme in estrogen biosynthesis, via immunohistochemistry. We found that renal HMGCR was more abundant in female compared to male rats maintained on a NS diet (P=0.0467). Increasing dietary salt intake upregulated renal HMGCR expression in male (P=0.0020), but not female rats (NS male; 100.0 ± 26.8 vs. NS female; 235.3 ± 23.2 vs. HS male 294.6 ± 42.0 vs HS female 314.6 ± 21.0 relative expression % NS male n=6-7/group). On a NS diet, renal StAR was more abundant in female compared to male rats (NS male; 100.0 ± 25.3 vs. NS female; 217.2 ± 36.5 relative expression % NS male P=0.0255 n=5-7/group). Increasing dietary salt did not alter expression of StAR in either sex. Similarly, renal SRD5A expression was higher in female compared to male (P=0.0141) rats. In addition, a HS diet increased the expression of SRD5A in female rats (0.0093) and tended to increase SRD5A expression in male (P=0.0849) rats (NS male; 100.0 ± 11.6 vs. NS female; 297.8 ± 37.7 vs. HS male 243.0 ± 39.2 vs HS female 498.8 ± 44.8 relative expression % NS male n=6-7/group). We also revealed that aromatase was expressed at a comparable level in male and female renal cortex, regardless of the diet (NS male; 2.4 ± 0.3 vs. NS female; 2.6 ± 0.3 vs. HS male 2.8 ± 0.3 vs HS female 1.9 ± 0.1 Average intensity x area mM2 n=6-9/group). Together, this data suggests that (i) the female kidney may be more primed for steroid biosynthesis and (ii) there is a sex-specific upregulation of the intrarenal sex steroid biosynthesis pathway in response to increasing dietary salt intake. Additional work is required to investigate the potential role of the kidney in androgen and estrogen production. A better understanding of this steroidogenic pathway could reveal novel sex-specific therapeutics for hypertension. T32DK007569-34 Carl Gottschalk Grant. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

In silico modelling of proteins encoded by important genes of flavonoid biosynthesis pathway in Gymnema sylvestre R. Br.

Understanding the proteins and metabolites produced by plants aids in developing superior planting materials. Gymnema sylvestre, a significant medicinal plant containing beneficial compounds such as oleanane, dammarane, flavonoids and gymnemic acids, exhibiting antioxidant and antidiabetic properties, making it a promising alternative treatment for Type 2 diabetes with minimal side effects. Transcriptomics in G. sylvestre yielded Coding DNA Sequences (CDS) for 12 key genes of flavonoid biosynthesis. Translated protein sequences of those 12 genes underwent characterization using protPARAM and i-TASSER. In silico protein modelling found similarities to validated enzymes, suggesting functional potential of the studied proteins. The study enlightens the first comprehensive insight into key proteins involved in G. sylvestre's flavonoid biosynthesis pathway. GsCHS (G. sylvestre chalcone synthase), a key enzyme in flavonoid biosynthesis, corroborated its phylogenetic proximity to Vincetoxicum mongolicum's CHS. Protein docking analysis delineated the distinctive features of GsCHS from cpCHS1 of Cyclosorus parasiticus, particularly in its substrate binding pockets and interactive sites crucial for synthesizing essential flavonoids.