A comprehensive review on marine algal polysaccharide-mediated siRNA delivery systems for biofuel production.

Novel variants of known natural product (NP) classes can provide valuable insights into their biosynthesis, mechanisms of action, and potential as drug leads across the entire class. Here, we describe a novel member of the widespread detoxine/rimosamide‐like (DRL) natural products, named pseudotetraivprolide, produced by Pseudomonas strains. Pseudotetraivprolide exhibits the characteristic DRL‐activity of protecting Bacillus cereus against the antibiotic blasticidin S. Through the generation of multiple deletion and complementation mutants, heterologous expression experiments, identification and structure elucidation of several derivatives, chemical synthesis of main derivatives, enzymatic characterization of individual biochemical steps, and detailed homology modelling of enzyme complexes, we elucidated key aspects of its biosynthesis. Our findings demonstrate that the primary metabolism‐derived malonyl CoA:ACP transacylase (FabD) functions as a trans‐AT in the biosynthesis pathway. Furthermore, we suggest an order for all late‐stage modifications and assign a function for the three conserved hypothetical proteins PipDFG acting as last‐step acetylation complex responsible for stabilization and activation of the final product.

To investigate into the role of leptin in body mass in high-fat-fed animals. Male striped field mice (Apodemus agrarius) fed high-fat diets were given leptin (0.5 μg/g.d) via intraperitoneal injection for 28 days. Their body mass, digestive metrics, and physiological parameters of food consumption and energy metabolism were compared to those of the control and high-fat food groups. Firstly, the high-fat diet did not cause weight gain in Apodemus agrarius, and the animals on the diet ate less and had higher apparent digestibility. Furthermore, exogenous leptin injection in A. agrarius reduced food intake, increased fecal content, and reduced apparent digestibility. Additionally, exogenous leptin injection inhibited the activity of the AMPK in the hypothalamus, increased the activity of malonyl CoA, inhibited the expression of orexigenic neuropeptide mRNA, promoted the expression of anorexigenic neuropeptide mRNA, and thus reduced food intake and body mass. Finally, exogenous leptin injection increased uncoupling protein 1 content, T45′-deiodinase II activity, and cytochrome C oxidase activity in brown adipose tissue, increased serum triiodothyronine, and increased animal energy consumption. In conclusion, our data indicate that leptin affects body mass in animals on a high-fat diet in two ways: by inhibiting food intake and increasing energy expenditure.

Introduction: Mitochondrial Ca 2+ flux has been extensively studied for its role in oxidative phosphorylation and necrotic cell death. Our recent studies in skeletal muscle suggest that enhanced mitochondrial Ca 2+ flux increases glucose oxidation and inhibition of mitochondrial Ca 2+ dynamics augments substrate use towards more fatty acid oxidation. Hypothesis: We hypothesize that mitochondrial Ca 2+ dynamics also regulates fuel selection in the heart. Objective: To investigate the cardiometabolic consequences of altered mitochondrial Ca 2+ dynamics in the heart. Methods: We developed a cardiac-specific MCUb overexpression mouse model to drive MCUb expression from development. Additionally, we employed AAV-mediated gene delivery to overexpress various MCU components ( Mcu , Mcub , and Micu3 ) to assess their individual contributions to cardiac metabolism. Results: MCUb induction in the heart enhanced cardiac function, evidenced by increased cardiac output. Gravimetric and electron microscopy analyses revealed signs of cardiac hypertrophy. Metabolically, MCUb overexpression in the heart resulted in decreased malonyl CoA levels, suggesting increased fatty acid oxidation (FAO) although these mice unexpectedly had increased fat accumulation over time. We also observed increased total acetylation with MCUb overexpression, but pyruvate dehydrogenase (PDH) and its phosphorylation were unchanged. AAV-baesd gene of select MCU components showed that both MCUb and MICU3 overexpression resulted in reduced ATP production and reduced Krebs cycle flux, further highlighting the metabolic consequences of disrupted mitochondrial Ca 2+ dynamics. Conclusions: Our findings support a critical role for mitochondrial Ca 2+ dynamics in regulating cardiac metabolism. Further studies are necessary to elucidate the molecular mechanisms driving the observed metabolic adaptations and to explore potential therapeutic implications.

Malonyl-CoA-acyl carrier protein transacylase (MCAT) catalyzes the transfer of a malonyl moiety from malonyl–CoA to acyl carrier protein during the initiation step of type II fatty acid synthesis (FASII). The Plasmodium FASII pathway was found to be essential for late liver-stage development in rodent malaria parasites. Here, we generated a novel genetically attenuated parasite (GAP) by disrupting Plasmodium MCAT. Deleting MCAT in rodent malaria parasites did not affect asexual blood-stage propagation and mosquito-stage development. MCAT KO sporozoites failed to initiate blood-stage infection in mice. Hepatic MCAT KO parasites showed impaired nuclear division and apicoplast biogenesis. This led to a defect in hepatic merozoite formation and attenuation of parasites during late liver stages. Vaccination of mice with MCAT KO sporozoites exhibited sterilizing immunity against homologous and heterologous species challenge. Further, MCAT KO-immunized mice were able to clear blood stage infection after iRBCs challenge. These findings highlight that late-liver arresting MCAT KO sporozoite is a promising GAP vaccine candidate for inducing pre-erythrocytic, stage, and species-transcending protection in mice.

Background: Cardiovascular diseases (CVDs) represent the most prevalent non-communicable diseases worldwide. In 2019, around 17.9 million individuals succumbed to cardiovascular diseases, accounting for 32% of all global fatalities. Mitochondria are essential for maintaining cellular metabolic equilibrium, facilitating cell survival and apoptosis, and generating the majority of cellular energy. Protein–protein interactions (PPIs) play a crucial role in both physiological and pathological processes, with abnormal PPIs linked to numerous disorders, making them prospective pharmacological targets across diverse therapeutic domains. Peptides are highly promising as protein-protein interaction inhibitors due to their capacity to replicate natural interaction patterns and encompass rather extensive interaction regions. Computational methods are extensively employed to accelerate drug discovery by screening prospective lead molecules. Purpose: Current work was designed to check efficacy of Daucus carota flavonoid for cardioprotective activity. Methodology: Scientific validation of the current investigation was done by computational based molecular docking study of lead molecules of Daucus carota pulp against malonyl Co-A decarboxylase enzyme. Result: The flavonoid found in D.carota has been identified as an effective cardioprotective drug and their lead molecules luteolin and apigenin demonstrating effective binding to the target protein malonyl Co-A decarboxylase with binding energies of -7.34 and -7.12 kcal/mol, respectively. Conclusion: The findings indicated that each selected lead chemical for additional investigation shown significant inhibitory activity against malonyl Co-A decarboxylase, hence revealing its cardio protection potential.

Heterologous expression of polyketide synthase (PKS) genes in Escherichia coli has enabled the production of various valuable natural and synthetic products. However, the limited availability of malonyl-CoA (M-CoA) in E. coli remains a substantial impediment to high-titer polyketide production. Here we address this limitation by disrupting the native M-CoA biosynthetic pathway and introducing an orthogonal pathway comprising a malonate transporter and M-CoA ligase, enabling efficient M-CoA biosynthesis under malonate supplementation. This approach substantially increases M-CoA levels, enhancing fatty acid and polyketide titers while reducing the promiscuous activity of PKSs toward undesired acyl-CoA substrates. Subsequent adaptive laboratory evolution of these strains provides insights into M-CoA regulation and identifies mutations that further boost M-CoA and polyketide production. This strategy improves E. coli as a host for polyketide biosynthesis and advances understanding of M-CoA metabolism in microbial systems.

Regulatory role of microcystin in the response of microcystin-producing cyanobacteria to elevated CO2: Insights from metabolic profiling

Triterpenoid saponins and flavonoids have several pharmacological activities against P. tenuifolia. The 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) and chalcone synthase (CHS) are the rate-limiting enzymes of triterpenoid saponin and flavonoid biosynthesis, respectively. In this study, HMGR and CHS genes were cloned from P. tenuifolia, and their bioinformatics analyses and tissue-specific expression were investigated. The results showed that the HMGR and CHS genes were successfully cloned, separately named the PtHMGR gene (NCBI accession: MK424118) and PtCHS gene (NCBI accession: MK424117). The PtHMGR gene is 2323 bp long, has an open reading frame (ORF) of 1782 bp, and encods 593 amino acids. The PtCHS gene is 1633 bp long with an ORF of 1170 bp, encoding 389 amino acids. PtHMGR and PtCHS were both hydrophobic, not signal peptides or secreted proteins, containing 10 conserved motifs. PtHMGR and PtCHS separately showed high homology with HMGR and CHS proteins from other species, and their secondary structures mainly included α-helix and random curl. The tertiary structure of PtHMGR was highly similarity to that the template 7ULI in RCSB PDB with 92.0% coverage rate. The HMG-CoA-binding domain of PtHMGR is located at 173-572 amino acid residues, including five bound sites. The tertiary structure of PtCHS showed high consistency with the template 1I86 in RCSB PDB with 100% coverage rate, contained malonyl CoA and 4-coumaroyl-CoA linkers. The expression of PtHMGR and PtCHS is tissue-specific. PtHMGR transcripts were mainly accumulated in roots, followed by leaves, and least in stems, and were significantly positively correlated with the contents of total saponin and tenuifolin. PtCHS was highly expressed in the stems, followed by the leaves, with low expression in the roots. PtCHS transcripts showed a significant positive correlation with total flavonoids content, however, they were significantly negatively correlated with the content of polygalaxanthone III (a type of flavonoids). This study provided insight for further revealing the roles of PtHMGR and PtCHS.

Angelica sinensis roots (Angelica roots) are rich in many bioactive compounds, including phthalides, coumarins, lignans, and terpenoids. However, the molecular bases for their biosynthesis are still poorly understood. Here, an improved chromosome-scale genome for A. sinensis var. Qinggui1 is reported, with a size of 2.16 Gb, contig N50 of 4.96 Mb and scaffold N50 of 198.27 Mb, covering 99.8% of the estimated genome. Additionally, by integrating genome sequencing, metabolomic profiling, and transcriptome analysis of normally growing and early-flowering Angelica roots that exhibit dramatically different metabolite profiles, the pathways and critical metabolic genes for the biosynthesis of these major bioactive components in Angelica roots have been deciphered. Multiomic analyses have also revealed the evolution and regulation of key metabolic genes for the biosynthesis of pharmaceutically bioactive components; in particular, TPSs for terpenoid volatiles, ACCs for malonyl CoA, PKSs for phthalide, and PTs for coumarin biosynthesis were expanded in the A. sinensis genome. These findings provide new insights into the biosynthesis of pharmaceutically important compounds in Angelica roots for exploration of synthetic biology and genetic improvement of herbal quality.

BackgroundOxytetracycline which is derived from Streptomyces rimosus, inhibits a wide range of bacteria and is industrially important. The underlying biosynthetic processes are complex and hinder rational engineering, so industrial manufacturing currently relies on classical mutants for production. While the biochemistry underlying oxytetracycline synthesis is known to involve polyketide synthase, hyperproducing strains of S. rimosus have not been extensively studied, limiting our knowledge on fundamental mechanisms that drive production.ResultsIn this study, a multiomics analysis of S. rimosus is performed and wild-type and hyperproducing strains are compared. Insights into the metabolic and regulatory networks driving oxytetracycline formation were obtained. The overproducer exhibited increased acetyl-CoA and malonyl CoA supply, upregulated oxytetracycline biosynthesis, reduced competing byproduct formation, and streamlined morphology. These features were used to synthesize bhimamycin, an antibiotic, and a novel microbial chassis strain was created. A cluster deletion derivative showed enhanced bhimamycin production.ConclusionsThis study suggests that the precursor supply should be globally increased to further increase the expression of the oxytetracycline cluster while maintaining the natural cluster sequence. The mutagenized hyperproducer S. rimosus HP126 exhibited numerous mutations, including large genomic rearrangements, due to natural genetic instability, and single nucleotide changes. More complex mutations were found than those typically observed in mutagenized bacteria, impacting gene expression, and complicating rational engineering. Overall, the approach revealed key traits influencing oxytetracycline production in S. rimosus, suggesting that similar studies for other antibiotics could uncover general mechanisms to improve production.

Inhibition of OAT1/3 and CMPF uptake attenuates myocardial ischemia-induced chronic heart failure via decreasing fatty acid oxidation and the therapeutic effects of ruscogenin

Numerous investigations have shown that insoluble dietary fiber (IDF) has a potentially positive effect on obesity due to a high-fat diet (HFD). Our previous findings based on proteomic data revealed that high-purity IDF from soybean residue (okara) (HPSIDF) prevented obesity by regulating hepatic fatty acid synthesis and degradation pathways, while its intervention mechanism is uncharted. Consequently, the goal of this work is to find out the potential regulatory mechanisms of HPSIDF on hepatic fatty acid oxidation by determining changes in fatty acid oxidation-related enzymes in mitochondria and peroxisomes, the production of oxidation intermediates and final products, the composition and content of fatty acids, and the expression levels of fatty acid oxidation-related proteins in mice fed with HFD. We found that supplementation with HPSIDF significantly ameliorated body weight gain, fat accumulation, dyslipidemia, and hepatic steatosis caused by HFD. Importantly, HPSIDF intervention promotes medium- and long-chain fatty acid oxidation in hepatic mitochondria by improving the contents of acyl-coenzyme A oxidase 1 (ACOX1), malonyl coenzyme A (Malonyl CoA), acetyl coenzyme A synthase (ACS), acetyl coenzyme A carboxylase (ACC), and carnitine palmitoyl transferase-1 (CPT-1). Moreover, HPSIDF effectively regulated the expression levels of proteins involved with hepatic fatty acid β-oxidation. Our study indicated that HPSIDF treatment prevents obesity by promoting hepatic mitochondrial fatty acid oxidation.

Fetal Hyperglycemia (FH) plays a critical role in adult obesity. FH occurs upon fetal exposure to high maternal glucose during Gestational Diabetes, resulting in hyperinsulinemia and increased fetal fat deposition. At birth, these infants are larger than normal babies, hypoglycemic and hyperinsulinemic and have a higher risk of adult-onset metabolic disorders such as obesity, Type 2 Diabetes and non-alcoholic fatty liver disease (NAFLD). Although in utero glucose exposure provides evidence in the above-mentioned conditions the molecular mechanisms remain unclear. Using a Zebrafish model of FH, we aim to test the hypothesis that FH increases hepatic de novo lipogenesis causing obesity later in life. Methods: We developed a novel Zebrafish model of FH by exposing embryos to high glucose (4.5% w/v) at day 4 post fertilization (4 dpf) during the last day of embryogenesis. At 5 dpf the glucose media was replaced by regular media with or without the Acetyl-CoA Carboxylase (acca) inhibitor ND646 for additional 24 hrs followed by embryo collection. Adult fish were raised from glucose-exposed embryos on a normal diet. Fat mass was assessed by Echo-MRI and glucose levels by glucometer. The substrate of de novo lipogenesis, malonyl CoA level was quantified by ELISA and triglycerides by colorimetry. Insulin expression (visualized by whole mount in-situ hybridization), lipogenic (acca), beta oxidation [(Carnitine palmitoyltransferase, (cpt1/2)] and gluconeogenic [(Glucagon (gcga), Glucose-6-Phosphatase (G6Pase), Phosphoenolpyruvate carboxykinase (pck1)] markers were quantified by RT-qPCR. Oil-Red-O staining (ORO) was used to detect lipid accumulation and quantified using spectrophotometry, while Nile red staining was used to detect adipocyte accumulation. Results: Zebrafish embryos become transiently hyperglycemic and hyperinsulinemic after 24 hrs of glucose exposure at 5 dpf. Surprisingly, despite being normoglycemic glucose-exposed embryos at 6 dpf showed significantly higher levels of hepatic lipid accumulation (48%) and de novo lipogenesis (acca and malonyl CoA) as well as markers of gluconeogenesis (gcga, G6Pase, pck1) and beta oxidation (cpt1/2), compared to controls. Interestingly, adult fish (3 months) become obese (fat mass, 2.5±0.2 vs 3.7±0.2) and develop epicardial fat deposition, despite being normoglycemic. At the molecular level, adult fish have increased fasting hepatic de novo lipogenesis, as indicated by elevated acca expression and malonyl CoA levels which was associated with higher hepatic triglyceride levels (1.5-fold) compared to adult fish raised from unexposed embryos. ND 646 administration reduced lipid accumulation in embryos. The effect of ND 646 on adult fish is under evaluation. Conclusion: Together our results show that FH induces persistent increase in whole embryonic and adult hepatic de novo lipogenesis and its pharmacological inhibition could be promising therapeutic intervention to rescue FH-induced adulthood obesity. National Institute of Health grant (P20 GM104357) This is the full abstract presented at the American Physiology Summit 2023 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.

This study examined the protective effect of 11-keto-β-boswellic acid (AKBA) against streptozotocin (STZ)-induced diabetic cardiomyopathy (DC) in rats and examined the possible mechanisms of action. Male rats were divided into 5 groups (n = 8/each): (1) control, AKBA (10 mg/kg, orally), STZ (65 mg/kg, i.p.), STZ + AKBA (10 mg/kg, orally), and STZ + AKBA + compound C (CC/an AMPK inhibitor, 0.2 mg/kg, i.p.). AKBA improved the structure and the systolic and diastolic functions of the left ventricles (LVs) of STZ rats. It also attenuated the increase in plasma glucose, plasma insulin, and serum and hepatic levels of triglycerides (TGs), cholesterol (CHOL), and free fatty acids (FFAs) in these diabetic rats. AKBA stimulated the ventricular activities of phosphofructokinase (PFK), pyruvate dehydrogenase (PDH), and acetyl CoA carboxylase (ACC); increased levels of malonyl CoA; and reduced levels of carnitine palmitoyltransferase I (CPT1), indicating improvement in glucose and FA oxidation. It also reduced levels of malondialdehyde (MDA); increased mitochondria efficiency and ATP production; stimulated mRNA, total, and nuclear levels of Nrf2; increased levels of glutathione (GSH), heme oxygenase (HO-1), superoxide dismutase (SOD), and catalase (CAT); but reduced the expression and nuclear translocation of NF-κB and levels of tumor-necrosis factor-α (TNF-α) and interleukin-6 (IL-6). These effects were concomitant with increased activities of AMPK in the LVs of the control and STZ-diabetic rats. Treatment with CC abolished all these protective effects of AKBA. In conclusion, AKBA protects against DC in rats, mainly by activating the AMPK-dependent control of insulin release, cardiac metabolism, and antioxidant and anti-inflammatory effects.

HPLC-MS-based untargeted metabolomic analysis of differential plasma metabolites and their associated metabolic pathways in reproductively anosmic black porgy, Acanthopagrus schlegelii

Sixteen new polyketides, ophicirsins A-P (1-16), including four novel carbon skeletons (5-9, 14, 15, and 16), were isolated from the extract of an endophytic fungus Ophiobolus cirsii LZU-1509. The unique frameworks of ophicirsin N (14) and O (15) feature a different cyclic ether connected with an aromatic ring system. Ophicirsin P (16) is characterized by the unprecedented heterozygote of a polyketide and an alkaloid. The absolute stereochemistries of those polyketides were characterized via single-crystal X-ray diffraction analysis and the experimental and computational electric circular dichroism spectra comparison. Theoretical reaction pathways in the fermentation to generate different novel skeletons starting from acetyl CoA and malonyl CoA helped to assign their structures. Compounds 1-16 appear almost nontoxic in HepG2 and HT-1080 tumor cells. Their antioxidant effects were further evaluated, and 15 exhibits an excellent protection activity in hydrogen peroxide-stimulated oxidative damage in neuron-like PC12 cells via screening all compounds. Moreover, 15 displays a greater ability to scavenge the 2,2-diphenyl-1-picrylhydrazyl free radicals than resveratrol. Taken together, these findings suggest that the novel polyketides could serve as potential antioxidant agents for neuroprotection.

Cholecalciferol improves insulin signaling and glucose metabolism in the heart and reduces circulating non-esterified fatty acids. Cholecalciferol effects on the cardiac fatty acid (FA) metabolism and the consequences on calcium handling were examined. Blood lipid profile was determined. Western blot and qRT-PCR were used to examine protein and mRNA expression. Cholecalciferoltreated rats had increased acetyl CoA carboxylase 2 protein expression and decreased expression of malonyl CoA decarboxylase. In addition, the expression of uncoupling protein 3 was elevated. Also, the level of peroxisome proliferator-activated receptor-gamma coactivator in the nucleus of heart cells was increased along with the level of sarcoplasmic/endoplasmic reticulum Ca2+ATPase in the microsomal fraction. In parallel, the L-type calcium channel and ryanodine receptor expression was reduced. In the heart of healthy rats, cholecalciferol affects proteins regulating malonyl CoA availability and intracellular Ca2+ handling proteins.

Flavonoids are valued for their beneficial properties. This was a proof-of-concept study to show that the PAL gene in Rhodosporidium toruloides (R. toruloides) could be harnessed and only two genes 4CL and CHS needed to be inserted to create the naringenin producing strain, CBS-N. The growth of CBS-N reached a higher OD600 86.1 compared to 31.8 by wildtype. High-performance liquid chromatography (HPLC) and liquid chromatography–mass spectrometry (LC–MS) confirmed CBS-N successfully produced 0.038 mg/L naringenin and 16.9 mg/L p-coumaric acid via its PAL/TAL activity when supplemented with tyrosine, although the conversion efficiency of 4CL and CHS genes was the limiting factor. Metabolic profiling by gas chromatography–mass spectrometry (GC–MS) showed that, in the CBS-N strain, metabolic flux was toward glycolysis and the TCA cycle to produce malonyl CoA, the precursor for naringenin synthesis, and away from fatty acids synthesis pathway. Our study showed that microorganisms containing a native PAL gene, such as R. toruloides, could be harnessed for flavonoids production via precision fermentation.

Simple SummaryAnimals can adapt to food shortages through phenotypic changes. In this study, food restriction reduced the body mass, RMR, serum leptin level, and POMC and CART gene expression in the red-backed vole, Eothenomys miletus; increased AMPK activity; and increased the concentration of ghrelin in the serum and stomach. The ghrelin-and-leptin-combined AMPK signaling pathway in the hypothalamus could play a role in the body mass regulation of E. miletus under food restriction. Moreover, regional differences in physiological indicators under food restriction may be related to the different temperatures or food resources in different regions.The phenotype plasticity of animals’ physiological characteristics is an important survival strategy to cope with environmental changes, especially the change in climate factors. Small mammals that inhabit seasonally changing environments often face the stress of food shortage in winter. This study measured and compared the thermogenic characteristics and related physiological indicators in the adenosine-5′-monophosphate-activated protein kinase (AMPK) pathway in Eothenomys miletus between Kunming (KM, n = 18) and Dali (DL, n = 18) under food restriction and refeeding. The results showed that food restriction and the region have significant effects on body mass, the resting metabolic rate (RMR), hypothalamic neuropeptide gene expression, ghrelin levels in the stomach and serum, serum leptin level and the activity of AMPK, and malonyl CoA and carnitine palmitoyltransferase 1 (CPT-1) activity. Food restriction reduced the body mass, the gene expression of neuropeptide proopiomelanocortin (POMC), cocaine- and amphetamine-regulated transcription peptide (CART), and leptin level. However, the ghrelin concentration and AMPK activity increased. After refeeding, there was no difference in these physiological indexes between the food restriction and control groups. Moreover, the physiological indicators also showed regional differences, such as the body mass, POMC and CART gene expression, ghrelin concentration in the stomach and serum, and AMPK activity in DL changed more significantly. All these results showed that food restriction reduces energy metabolism in E. miletus. After refeeding, most of the relevant physiological indicators can return to the control level, indicating that E. miletus has strong phenotypic plasticity. Ghrelin, leptin, and the AMPK pathway play an important role in the energy metabolism of E. miletus under food restriction. Moreover, regional differences in physiological indicators under food restriction may be related to the different temperatures or food resources in different regions.