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PloS One 2024Aluminum (Al) toxicity is an important factor restricting the normal growth of plants in acidic soil. Rhododendron (Ericaceae) can grow relatively well in acidic soil....
Aluminum (Al) toxicity is an important factor restricting the normal growth of plants in acidic soil. Rhododendron (Ericaceae) can grow relatively well in acidic soil. To uncover the adaptive mechanisms of photosynthesis under Al stress, the influence of Al stress on the photosynthetic activities of Al-sensitive (Baijinpao) and Al-resistant (Kangnaixin) rhododendron cultivars was examined by measuring gas exchange, chlorophyll fluorescence, and the modulated reflection of light at 820 nm. Under Al stress conditions, the net photosynthetic rate and stomatal conductance of the rhododendron leaves decreased, whereas the intercellular CO2 concentration increased. The Al stress treatment damaged the oxygen-evolving complex of the rhododendron seedlings, while also inhibiting electron transport on the photosystem II (PSII) donor side. In addition, the exposure to Al stress restricted the oxidation of plastocyanin (PC) and the photosystem I (PSI) reaction center (P700) and led to the re-reduction of PC+ and P700+. The comparison with Kangnaixin revealed an increase in the PSII connectivity in Baijinpao. Additionally, the donor-side electron transport efficiency was more inhibited and the overall activity of PSII, PSI, and the intersystem electron transport chain decreased more extensively in Baijinpao than in Kangnaixin. On the basis of the study findings, we concluded that Al stress adversely affects photosynthesis in rhododendron seedlings by significantly decreasing the activity of PSII and PSI. Under Al stress, Kangnaixin showed stronger tolerance compared with Baijinpao.
Topics: Rhododendron; Aluminum; Chlorophyll; Photosynthesis; Fluorescence; Photosystem II Protein Complex; Stress, Physiological; Plant Leaves; Electron Transport; Light; Photosystem I Protein Complex
PubMed: 38935623
DOI: 10.1371/journal.pone.0305133 -
Organic Letters Jun 2024Pyrrole alkaloids (PAs) are a diverse class of natural products with complex carbon frameworks and broad bioactivities that are usually derived from marine sponges. and...
Pyrrole alkaloids (PAs) are a diverse class of natural products with complex carbon frameworks and broad bioactivities that are usually derived from marine sponges. and are two independent sponges collected from the South China Sea in 2013 and 2018, respectively. We discovered PAs are common constituents in both two sponges; more specifically, produces pyrrole-imidazole alkaloids, and contains pyrrolidone alkaloids. In this study, three pyrrole steroid metabolites were obtained. Compounds and are a pair of epimers sharing a new 5/7/5/6/6 pentacyclic structural configuration, and compound has a new rigid 5/6/6 tricyclic structure. Interestingly, their scaffolds all possess a 6/6 bicyclic system on the featured classic pyrrole/pyrrolidone skeletons, so-dubbed tagpyrrollins A and B ( and , respectively) and tagpyrrollidone A (). From a biosynthetic viewpoint, 4,5-dihydroxypent-2-enal probably plays a crucial role in constructing these pyrrole steroid analogues. Based on our previous study on the inhibitory activity of spongiacidin targeting AKR1B1, a drug target for the treatment of chronic diabetic complications, in this study we found that tagpyrrolin A () also exhibits an inhibitory effect against AKR1B1.
PubMed: 38935544
DOI: 10.1021/acs.orglett.4c01976 -
Journal of the American Chemical Society Jun 2024Herein, we report room temperature, atom-economic protocols for high regio- and enantioselective tandem cycloisomerization-hydroarylation and...
Ligand Effects in Carboxylic Ester- and Aldehyde-Assisted β-C-H Activation in Regiodivergent and Enantioselective Cycloisomerization-Hydroalkenylation and Cycloisomerization-Hydroarylation, and [2 + 2 + 2]-Cycloadditions of 1,6-Enynes.
Herein, we report room temperature, atom-economic protocols for high regio- and enantioselective tandem cycloisomerization-hydroarylation and cycloisomerization-hydroalkenylation of 1,6-enynes leading to vicinal -functionalized pyrrolidines, tetrahydrofurans, and cyclopentanes. The latter steps in these processes involve carbonyl-coordination-assisted C-H activation of aromatic aldehydes and esters, and, a similar, yet rarely seen, β-C-H activation in the case of the acrylates. Synthetically useful enantioselective versions of such reactions are rare and are limited to the C-H activation of indoles and pyrroles. A similar reaction is also observed with -vinylphthalimide, which also has a carbonyl group suitable for C-H activation. A dibenzooxaphosphole ligand, (2,2,33)-MeO-BIBOP was uniquely identified as crucial to achieving the challenging regio- and enantioselectivity. This methodology gives access to substituted five-membered carbo- and heterocyclic compounds in good yields and excellent enantioselectivities under a low catalyst loading. A primary KIE of 3.5 is observed in an intermolecular competition experiment with methyl benzoate and -methyl benzoate, which indicates that the C-H cleavage is the turnover-limiting step of this process. Unlike the acrylates, which undergoes exclusive hydroalkenylation, a β, γ-unsaturated ester, methyl but-3-enoate, undergoes the highly enantioselective cycloisomerization-coupling sequence with a 1,6-enyne giving either a [2 + 2 + 2]-cycloaddition with ()-BDPP or hydroalkenylation with (2,2',3,3')-MeO-BIBOP depending on the ligand employed. The ()-configuration of the newly formed double bond at the terminal alkynyl carbon (of the starting enyne) in the hydroalkenylation product of β,γ-unsaturated ester suggests a more classical migratory insertion-β-hydride elimination route for the formation of this product.
PubMed: 38935521
DOI: 10.1021/jacs.4c06796 -
TAG. Theoretical and Applied Genetics.... Jun 2024Phosphorus (P) is an essential element for plant growth, and its deficiency can cause decreased crop yield. This study systematically evaluated the low-phosphate (Pi)...
Phosphorus (P) is an essential element for plant growth, and its deficiency can cause decreased crop yield. This study systematically evaluated the low-phosphate (Pi) response traits in a large population at maturity and seedling stages, and explored candidate genes and their interrelationships with specific traits. The results revealed a greater sensitivity of seedling maize to low-Pi stress compared to that at maturity stage. The phenotypic response patterns to low-Pi stress at different stages were independent. Chlorophyll content was found to be a potential indicator for screening low-Pi-tolerant materials in the field. A total of 2900 and 1446 significantly associated genes at the maturity and seedling stages were identified, respectively. Among these genes, 972 were uniquely associated with maturity traits, while 330 were specifically detected at the seedling stage under low-Pi stress. Moreover, 768 and 733 genes were specifically associated with index values (low-Pi trait/normal-Pi trait) at maturity and seedling stage, respectively. Genetic network diagrams showed that the low-Pi response gene Zm00001d022226 was specifically associated with multiple primary P-related traits under low-Pi conditions. A total of 963 out of 2966 genes specifically associated with traits under low-Pi conditions or index values were found to be induced by low-Pi stress. Notably, ZmSPX4.1 and ZmSPX2 were sharply up-regulated in response to low-Pi stress across different lines or tissues. These findings advance our understanding of maize's response to low-Pi stress at different developmental stages, shedding light on the genes and pathways implicated in this response.
Topics: Zea mays; Seedlings; Stress, Physiological; Phenotype; Phosphorus; Genes, Plant; Genome-Wide Association Study; Chlorophyll; Quantitative Trait Loci; Gene Expression Regulation, Plant; Genetic Association Studies; Polymorphism, Single Nucleotide
PubMed: 38935162
DOI: 10.1007/s00122-024-04681-2 -
Physical Chemistry Chemical Physics :... Jun 2024Exploring efficient and low-cost oxygen reduction and oxygen evolution reaction (ORR/OER) bifunctional catalysts is essential for the development of energy storage and...
Exploring efficient and low-cost oxygen reduction and oxygen evolution reaction (ORR/OER) bifunctional catalysts is essential for the development of energy storage and conversion devices. Herein, enlightened by the experimentally synthesized cobalt(II) -tetraethynylporphyrins (Co-TEP) molecule, we designed a novel 2D covalent organic framework (COF), namely a 2D Co-TEP monolayer, by dimensional expansion. The 2D Co-TEP monolayer, with Co atoms distributed separately and stabilized by uniform pyrrolic-N coordination, features metal-nitrogen-carbon single-atom catalyst activity and shows tunable catalytic activity for the electrochemical ORR/OER by axial ligand (O, OH, Cl, CN, CH, NO, F) modulation. By means of the state-of-the-art constant-potential first-principles computations and microkinetic simulations, we demonstrated that 2D Co-TEP-CN exhibits good ORR/OER performance in both acidic and alkaline conditions. The difference between the onset-potential for the OER and the half-wave potential for the ORR is only 0.85 V at pH = 1, smaller than that of Pt/IrO electrocatalysts. The good electrocatalytic performance is maintained by replacing the center metal atoms with Mn, Fe and/or Ni. Our investigation highlights the role of the pyrrolic-N coordination and the ligands in improving the catalytic activity of 2D COFs and provides new insights into the rational design of efficient bifunctional ORR/OER catalysts.
PubMed: 38932574
DOI: 10.1039/d4cp01235f -
Nutrients Jun 2024Free radicals and reactive oxygen species initiate when the oxidative stress arises. (1) Background: The effect of natural molecules on oxidative stress in...
Free radicals and reactive oxygen species initiate when the oxidative stress arises. (1) Background: The effect of natural molecules on oxidative stress in hyperlipidemic rats, taking statins, was observed. (2) Methods: One hundred and twelve white Wistar rats, males and females, were divided into seven: Group I received 20 mg of atorvastatin while groups II and III received a combination of 20 mg of atorvastatin and 100 mg of Sea buckthorn and grape extract. Groups IV and V received 100 mg of Sea buckthorn and grape extract, while groups VI and VII received only high-fat diet (HFD) and normal rodents' fodder. After two and six months, rats were euthanized, and blood was gathered to measure the main paraclinical values and total antioxidant capacity (TAC). Also, the liver and kidney were stored for the organs' cytoarchitecture. For statistics, two-way analysis of variance (ANOVA), was performed. (3) Results: HFD produced hyperlipidemia, accompanied by augmented serum and hepatic oxidative stress markers, in addition to a reduction in antioxidant enzyme activities and glutathione levels. Polyphenolic substances proven efficient against HFD caused oxidative stress. (4) Conclusions: Atorvastatin heightened the histological injuries caused by the fatty diet, but these were diminished by taking atorvastatin in combination with 100 mg/kg of plant extracts.
Topics: Animals; Atorvastatin; Oxidative Stress; Rats, Wistar; Hyperlipidemias; Male; Hippophae; Vitis; Plant Extracts; Female; Antioxidants; Diet, High-Fat; Liver; Rats; Biomarkers; Kidney
PubMed: 38931308
DOI: 10.3390/nu16121954 -
Nutrients Jun 2024Polycystic ovary syndrome (PCOS) is a common endocrine disorder that affects women of reproductive age. Many women with PCOS have been found to have an unbalanced diet...
Polycystic ovary syndrome (PCOS) is a common endocrine disorder that affects women of reproductive age. Many women with PCOS have been found to have an unbalanced diet and deficiencies in essential nutrients. This study aimed to assess the levels of folate and vitamin B12 (B12) and their relationship with metabolic factors in women with PCOS. Anthropometric, clinical, and genetic analyses were conducted to evaluate markers related to one-carbon metabolism in women with PCOS and in a control group. The PCOS group had a higher BMI and HOMA-IR (1.7 vs. 3.1; < 0.0001). HDL cholesterol levels were 23% lower and triglyceride levels were 74% higher in women with PCOS. Although there were no significant differences in folate and B12 levels between the PCOS and control groups, over 60% of women with PCOS had low B12 levels (<300 pg/mL) and high homocysteine levels. In addition, the MTHFR A1298C and C677T polymorphisms were not associated with PCOS. Moreover, erythrocyte folate levels were positively correlated with fasting glucose, triglycerides, and free androgen index, and negatively correlated with SHBG and LH levels. These results suggest that B vitamins may be associated with the metabolic phenotype in PCOS. This study emphasizes the potential link between folate, vitamin B12, and metabolic and hormonal outcomes in women with PCOS.
Topics: Humans; Female; Polycystic Ovary Syndrome; Vitamin B 12; Folic Acid; Adult; Chile; Young Adult; Triglycerides; Homocysteine; Body Mass Index; Blood Glucose; Methylenetetrahydrofolate Reductase (NADPH2); Insulin Resistance; Cholesterol, HDL; Case-Control Studies; Biomarkers
PubMed: 38931291
DOI: 10.3390/nu16121937 -
Molecules (Basel, Switzerland) Jun 2024MnO has attracted much attention as the anode for Li-ion batteries (LIBs) owing to its high specific capacity. However, the low conductivity limited its large...
MnO has attracted much attention as the anode for Li-ion batteries (LIBs) owing to its high specific capacity. However, the low conductivity limited its large application. An effective solution to solve this problem is carbon coating. Biomass carbon materials have aroused much interest for being low-cost and rich in functional groups and hetero atoms. This work designs porous N-containing MnO composites based on the chemical-activated tremella using a self-templated method. The tremella, after activation, could offer more active sites for carbon to coordinate with the Mn ions. And the as-prepared composites could also inherit the special porous nanostructures of the tremella, which is beneficial for Li transfer. Moreover, the pyrrolic/pyridinic N from the tremella can further improve the conductivity and the electrolyte wettability of the composites. Finally, the composites show a high reversible specific capacity of 1000 mAh g with 98% capacity retention after 200 cycles at 100 mA g. They also displayed excellent long-cycle performance with 99% capacity retention (relative to the capacity second cycle) after long 1000 cycles under high current density, which is higher than in most reported transition metal oxide anodes. Above all, this study put forward an efficient and convenient strategy based on the low-cost biomass to construct N-containing porous composite anodes with a fast Li diffusion rate, high electronic conductivity, and outstanding structure stability.
PubMed: 38931003
DOI: 10.3390/molecules29122939 -
Molecules (Basel, Switzerland) Jun 20243,4-Fused pyrrolocoumarins, synthetically prepared or naturally occurring, possess interesting biological properties. In this review, the synthetic strategies for the... (Review)
Review
3,4-Fused pyrrolocoumarins, synthetically prepared or naturally occurring, possess interesting biological properties. In this review, the synthetic strategies for the synthesis of the title compounds are presented along with their biological activities. Two routes are followed for that synthesis. In one, the pyrrole ring is formed from coumarin derivatives, such as aminocoumarins or other coumarins. In the other approach, the pyranone moiety is built from an existing pyrrole derivative or through the simultaneous formation of coumarin and pyrrole frameworks. The above syntheses are achieved via 1,3-dipolar cycloaddition reactions, Michael reaction, aza-Claisen rearrangement reactions, multi-component reactions (MCR), as well as metal-catalyzed reactions. Pyrrolocoumarins present cytotoxic, antifungal, antibacterial, α-glucosidase inhibition, antioxidant, lipoxygenase (LOX) inhibition, and fluorescent activities, as well as benzodiazepine receptor ability.
Topics: Coumarins; Pyrroles; Humans; Antioxidants; Molecular Structure; Cycloaddition Reaction
PubMed: 38930816
DOI: 10.3390/molecules29122748 -
International Journal of Molecular... Jun 2024Hell's Gate globin-I (HGb-I) is a thermally stable globin from the aerobic methanotroph . Here we report that HGb-I interacts with lipids stoichiometrically to induce...
Hell's Gate globin-I (HGb-I) is a thermally stable globin from the aerobic methanotroph . Here we report that HGb-I interacts with lipids stoichiometrically to induce structural changes in the heme pocket, changing the heme iron distal ligation coordination from hexacoordinate to pentacoordinate. Such changes in heme geometry have only been previously reported for cytochrome c and cytoglobin, linked to apoptosis regulation and enhanced lipid peroxidation activity, respectively. However, unlike cytoglobin and cytochrome c, the heme iron of HGb-I is altered by lipids in ferrous as well as ferric oxidation states. The apparent affinity for lipids in this thermally stable globin is highly pH-dependent but essentially temperature-independent within the range of 20-60 °C. We propose a mechanism to explain these observations, in which lipid binding and stability of the distal endogenous ligand are juxtaposed as a function of temperature. Additionally, we propose that these coupled equilibria may constitute a mechanism through which this acidophilic thermophile senses the pH of its environment.
Topics: Hydrogen-Ion Concentration; Temperature; Globins; Lipids; Heme; Protein Conformation; Models, Molecular; Bacterial Proteins
PubMed: 38928500
DOI: 10.3390/ijms25126794