Nomogram to predict severe retinopathy of prematurity in Southeast China.

AIM: To define the predictive factors of severe retinopathy of prematurity (ROP) and develop a nomogram for predicting severe ROP in southeast China. METHODS: Totally 554 infants diagnosed with ROP hospitalized in the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University and hospitalized in Taizhou Women and Children's Hospital were included. Clinical data and 43 candidate predictive factors of ROP infants were collected retrospectively. Logistic regression model was used to identify predictive factors of severe ROP and to propose a nomogram for individual risk prediction, which was compared with WINROP model and Digirop-Birth model. RESULTS: Infants from the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University (n=478) were randomly allocated into training (n=402) and internal validation group (n=76). Infants from Taizhou Women and Children's Hospital were set as external validation group (n=76). Severe ROP were found in 52 of 402 infants, 12 of 76 infants, and 7 of 76 infants in training group, internal validation group, and external validation group, respectively. Birth weight [odds ratio (OR), 0.997; 95% confidence interval (CI), 0.996-0.999; P<0.001], multiple births (OR, 1.885; 95%CI, 1.013-3.506; P=0.045), and non-invasive ventilation (OR, 0.288; 95%CI, 0.146-0.570; P<0.001) were identified as predictive factors for the prediction of severe ROP, by univariate analysis and multivariate analysis. For predicting severe ROP based on the internal validation group, the areas under receiver operating characteristic curve (AUC) was 78.1 (95%CI, 64.2-92.0) for the nomogram, 32.9 (95%CI, 15.3-50.5) for WINROP model, 70.2 (95%CI, 55.8-84.6) for Digirop-Birth model. In external validation group, AUC of the nomogram was also higher than that of WINROP model and Digirop-Birth model (80.2 versus 51.1 and 63.4). The decision curve analysis of the nomogram demonstrated better clinical efficacy than that of WINROP model and Digirop-Birth model. The calibration curves demonstrated a good consistency between the actual severe ROP incidence and the predicted probability. CONCLUSION: Birth weight, multiple births, and non-invasive ventilation are independent predictors of severe ROP. The nomogram has a good ability to predict severe ROP and performed well on internal validation and external validation in southeast China.

Uracil hydrazones: design, synthesis, antimicrobial activities, and putative mode of action.

BACKGROUND: Crop diseases caused by plant pathogenic fungi and bacteria have led to substantial losses in global food production. Chemical pesticides have been widely used as a primary means to mitigate these issues. Nevertheless, the persistent and excessive use of pesticides has resulted in the emergence of microbial resistance. Moreover, the improper application and excessive utilization of pesticides can contribute to environmental pollution and the persistence of pesticide residues. Consequently, the development of novel and highly effective bactericides and fungicides to combat plant pathogens holds immense practical importance. RESULTS: A series of uracil hydrazones IV-B was deliberately designed and evaluated for their antimicrobial efficacy. The results of bioassays indicated that most IV-B exhibited >80% inhibition against the fungal species Monilia fructigena and Sclerotium rolfsii, as well as the bacterial species Clavibacter michiganensis subsp. michiganensis, Xanthomonas oryzae pv. oryzae, and Ralstonia solanacearum, at 50 µg/mL in vitro. In vivo, IV-B20 showed 89.9% of curative and 71.8% of protective activities against C. michiganensis subsp. michiganensis at 100 µg/mL superior to thiodiazole copper and copper hydroxide. IV-B20 also showed excellent protective activity against M. fructigena (96.3% at 200 µg/mL) and S. rolfsii (80.4% at 1000 µg/mL), which were greater than chlorothalonil and equivalent to thifluzamide. Mechanistic studies revealed that IV-B20 induced oxidative damage in pathogenic bacteria and promoted the leakage of cellular contents. CONCLUSION: This study suggests that IV-B20 with uracil hydrazone skeleton has great potential as an antimicrobial candidate. These findings lay a foundation for practical application in agriculture. © 2023 Society of Chemical Industry.

RETINAL MICROVASCULOPATHY WITH DIFFERENT INSULIN INFUSION THERAPIES IN CHILDREN WITH TYPE 1 DIABETES MELLITUS WITHOUT CLINICAL DIABETIC RETINOPATHY.

PURPOSE: To explore the characteristics and associated factors of retinal microvasculopathy and neurodegeneration with different insulin therapies in children with type 1 diabetes mellitus (T1DM) but without diabetic retinopathy. METHODS: Forty-one children with T1DM with multiple daily insulin injections (MDI), 22 children with T1DM with continuous subcutaneous insulin infusion, and 62 age-matched normal control children were enrolled. SPECTRALIS Optical coherence tomography was used to scan 6×6 mm square area of posterior retina. RESULTS: The vessel density of superficial vascular plexus, intermediate capillary plexus, and deep capillary plexus in T1DM-MDI group were all significantly lower than those in the T1DM-CSII and control groups (0.39 ± 0.05 vs. 0.44 ± 0.04 and 0.42 ± 0.06, P < 0.001; 0.26 ± 0.04 vs. 0.30 ± 0.02 and 0.28 ± 0.04, P = 0.003; 0.30 ± 0.04 vs. 0.33 ± 0.04 and 0.32 ± 0.04, P = 0.027). In T1DM-MDI group, lower vessel density of superficial vascular plexus was associated with higher hemoglobin A1c (r = -0.377, P = 0.015). Foveal avascular zone morphology index in T1DM-MDI and T1DM-CSII groups were smaller than that in the control group (0.63 ± 0.11 and 0.63 ± 0.12 vs. 0.69 ± 0.15, P = 0.040). There was no statistically significant difference in the thickness of the retina among the three groups ( P > 0.05). CONCLUSION: The vessel density of posterior retina was lower in children with T1DM with MDI than in healthy control children and associated with higher hemoglobin A1c. There was a significant difference on vessel density betweenT1DM-MDI and T1DM-CSII, with the similar hemoglobin A1c. This study suggested that optical coherence tomography angiography could be beneficial for the detection of retinal abnormalities in children with early T1DM, and continuous subcutaneous insulin infusion may be a better choice than MDI for children with T1DM to prevent the retinal complication.

Reprogramming Short-Chain Fatty Acid Metabolism Mitigates Tissue Damage for Streptococcus pyogenes Necrotizing Skin Infection.

Disease Tolerance (DT) is a host response to infection that limits collateral damage to host tissues while having a neutral effect on pathogen fitness. Previously, we found that the pathogenic lactic acid bacterium Streptococcus pyogenes manipulates DT using its aerobic mixed-acid fermentation (ARMAF) pathway via the enzyme pyruvate dehydrogenase (PDH) to alter expression of the immunosuppressive cytokine IL-10. However, the microbe-derived molecules that mediate communication with the host's DT pathways remain elusive. Here, we show that ARMAF inhibits accumulation of IL-10-producing inflammatory cells including neutrophils and macrophages, leading to delayed bacterial clearance and wound healing. Expression of IL-10 is inhibited through streptococcal production of the short chain fermentation end-products acetate and formate, via manipulation of host acetyl-CoA metabolism, altering non-histone regulatory lysine acetylation. A bacterial-specific PDH inhibitor reduced tissue damage during murine infection, suggesting that reprogramming carbon flow provides a novel therapeutic strategy to mitigate tissue damage during infection.

Design, synthesis, high algicidal potency, and putative mode of action of new 2-cyclopropyl-4-aminopyrimidine hydrazones.

Control of cyanobacteria harmful algal blooms remains a global challenge. In the present study, a series of novel 2-cyclopropyl-4-aminopyrimidine hydrazones were designed and synthesized as potential algicides. Compounds 4a, 4b, 4h, 4j, 4k, 4l, and 4m showed potent inhibition against Synechocystis sp. PCC6803 (median effective concentration, EC50 = 1.1 to 1.7 µM) and Microcystis aeruginosa FACHB905 (EC50 = 1.2 to 2.0 µM), more potent than, or comparably with, copper sulfate (PCC6803, EC50 = 1.8 µM; FACHB905, EC50 = 2.2 µM) and prometryne (PCC6803, EC50 = 12.3 µM; FACHB905, EC50 = 7.2 µM). Compound 4k exhibited algicidal activity in an expanded culture system, and was less toxic than copper sulfate to zebrafish. Electron microscope analyses showed that 4k damaged cyanobacterial cells and decreased the number of thylakoid lamellae. Transcriptomic and qPCR analyses suggest that 4k interfered photosynthesis-related pathways. Treatment with 4k significantly decreased the maximum quantum yield of photosystem II and the photosynthetic electron transfer rate, and the resulting reactive oxygen species damaged thylakoid membranes and photosystem I. The results suggest that 4k is a potential lead for further development of effective and safe algicides.

Discovery of efficient inhibitors against pyruvate dehydrogenase complex component E1 with bactericidal activity using computer aided design.

Computer aided optimization of lead compounds is of great significance to the design and discovery of new agrochemicals. A series of 2,6-dimethyl-4-aminopyrimidine acylhydrazones 6 was rationally designed as pyruvate dehydrogenase complex component E1 (PDHc-E1) inhibitors using computer aided drug design. Compounds in series 6 showed excellent inhibitory activity against Escherichia coli PDHc-E1, which was considerably higher than that of the lead compound A2. Compound 6l showed the best inhibitory activity (IC50 = 95 nM). Molecular docking, site-directed mutagenesis, and enzymatic assays revealed that the compounds bound in a "straight" conformation in the active site of E. coli PDHc-E1. Compounds 6b, 6e, and 6l showed negligible inhibition against porcine PDHc-E1. The in vitro antibacterial activity indicated that 6a, 6d, 6e, 6g, 6h, 6i, 6m, and 6n exhibited 61%-94% inhibition against Ralstonia solanacearum at 100 µg/mL, which was better than commercial thiodiazole­copper (29%) and bismerthiazol (55%). These results demonstrated that a lead structure for a highly selective PDHc-E1 inhibitor as a bactericide could be obtained using computer aided drug design.

Design, Synthesis, and Antifungal Activity of 2,6-Dimethyl-4-aminopyrimidine Hydrazones as PDHc-E1 Inhibitors with a Novel Binding Mode.

A series of novel 2,6-dimethyl-4-aminopyrimidine hydrazones 5 were rationally designed and synthesized as pyruvate dehydrogenase complex E1 (PDHc-E1) inhibitors. Compounds 5 strongly inhibited Escherichia coli (E. coli) PDHc-E1 (IC50 values 0.94-15.80 µM). As revealed by molecular docking, site-directed mutagenesis, enzymatic, and inhibition kinetic analyses, compounds 5 competitively inhibited PDHc-E1 and bound in a "straight" pattern at the E. coli PDHc-E1 active site, which is a new binding mode. In in vitro antifungal assays, most compounds 5 at 50 µg/mL showed more than 80% inhibition against the mycelial growth of six tested phytopathogenic fungi, including Botrytis cinerea, Monilia fructigena, Colletotrichum gloeosporioides, andBotryosphaeria dothidea. Notably, 5f and 5i were 1.8-380 fold more potent against M. fructigena than the commercial fungicides captan and chlorothalonil. In vivo, 5f and 5i controlled the growth of M. fructigena comparably to the commercial fungicide tebuconazole. Thus, 5f and 5i have potential commercial value for the control of peach brown rot caused by M. fructigena.

Structure optimization and bioactivity evaluation of ThDP analogs targeting cyanobacterial pyruvate dehydrogenase E1.

Harmful cyanobacteria bloom (HCB) has occurred frequently in recent years and it is urgent to develop novel algicides to deal with this problem. In this paper, a series of novel thiamin diphosphate (ThDP) analogs 5a-5g were designed and synthesized targeting cyanobacterial pyruvate dehydrogenase complex E1 (Cy-PDHc E1). Our results showed that compounds 5a-5g have higher inhibitory activities against Cy-PDHc E1 (IC50 9.56-3.48 µM) and higher inhibitory activities against two model cyanobacteria strains Synechocystis sp PCC6803 (EC50 2.03-1.58 µM) and Microcystis aeruginosa FACHB905 (EC50 1.86-0.95 µM). Especially, compound 5b displayed highest inhibitory activities (IC50 = 3.48 µM) against Cy-PDHc E1 and powerful inhibitory activities against cyanobacteria Synechocystis sp PCC6803 (EC50 = 1.58 µM) and Microcystis aeruginosa FACHB905 (EC50 = 1.04 µM). Moreover, the inhibitory activities of compound 5b were even higher than those of copper sulfate (EC50 = 2.02 and 1.71 µM separately) which has been widely used as algicide against cyanobacteria PCC6803 and FACHB905. The more important was that compound 5b display much higher inhibitory selectivity between Cy-PDHc E1 (Inhibitory rate 97.4%) and porcine PDHc E1 (Inhibitory rate 11.8%) under the same concentration (100 µM). The inhibition kinetic experiment and molecular docking research showed that compound 5b can inhibit Cy-PDHc E1 by occupying the ThDP-binding pocket and then blocking Cy-PDHc E1 bound to ThDP as competitive inhibitor. The imagines of SEM and TEM showed that cellular microstructures were heavily destroyed under compound 5b stress. Our results demonstrated compound 5b could be taken as a potential lead compound targeting Cy-PDHc E1 to obtain environment-friendly algicide for harmful cyanobacterial blooms control.

Synthesis and Activity of 1,2,3-Triazole Aminopyrimidines against Cyanobacteria as PDHc-E1 Competitive Inhibitors.

Cyanobacteria harmful algal blooms are of global concern, but all currently available algicides in the market are nonselective and have potential side effects on nontarget species. In the present work, two series of compounds (4 and 6) comprising 16 novel 1,2,3-triazole aminopyrimidines were rationally designed and synthesized as control agent for cyanobacteria. Our design focus was the inhibiting cyanobacteria by inhibition against pyruvate dehydrogenase complex E1 (PDHc-E1). Compounds 4 and 6 showed potent inhibition against Escherichia coli PDHc-E1 (IC50 = 4.13-23.76 µM) and also strong algicidal activities against Synechocystis sp. PCC 6803 (EC50 = 1.7-8.1 µM) and Microcystis sp. FACHB905 (EC50 = 2.1-11.8 µM). In particular, the algicidal activities of 6d against four algal species were not only higher than that of prometryn; they were also comparable to or higher than that of copper sulfate. The analogues 4c, 4d, 6d, and 6e displayed potent algicidal activities and inhibition of E. coli PDHc-E1 but exhibited negligible inhibition of porcine PDHc-E1. As revealed by molecular docking, site-directed mutagenesis, enzymatic assays, and an inhibition kinetic analysis, 4c and 6d inhibited PDHc-E1 in a competitive manner. Our results suggest that highly selective, effective algicides can be developed by rationally designing competitive PDHc-E1 inhibitors.

Design, synthesis and biological evaluation of novel inhibitors against cyanobacterial pyruvate dehydrogenase multienzyme complex E1.

Cyanobacterial pyruvate dehydrogenase multienzyme complex E1 (PDHc E1) is a potential target enzyme for finding inhibitors to control harmful cyanobacterial blooms. In this study, a series of novel triazole thiamin diphosphate (ThDP) analogs were designed and synthesized by modifying the substituent group of triazole ring and optimizing triazole-benzene linker as potential cyanobacterial PDHc E1 (Cy-PDHc E1) inhibitors. Their inhibitory activities against Cy-PDHc E1 in vitro and algicide activities in vivo were further examined. Most of these compounds exhibited prominent inhibitory activities against Cy-PDHc E1 (IC50 1.48-4.48 µM) and good algicide activities against Synechocystis PCC6803 (EC50 0.84-2.44 µM) and Microcystis aeruginosa FACHB905 (EC50 0.74-1.77 µM). Especially, compound 8d showed not only the highest inhibitory activity against Cy-PDHc E1 (IC50 1.48 µM), but also the most powerful inhibitory selectivity between Cy-PDHc E1 (inhibitory rate 98.90%) and porcine PDHc E1 (inhibitory rate only 9.54%). Furthermore, the potential interaction between compound 8d and Cy-PDHc E1 was analyzed by a molecular docking method and site-directed mutagenesis and enzymatic analysis and fluorescence spectral analysis. These results indicated that compound 8d could be used as a hit compound for further optimization and might have potential to be developed as a new algicide.

Design and synthesis of highly selective pyruvate dehydrogenase complex E1 inhibitors as bactericides.

In order to obtain PDHc-E1 inhibitors with high selectivity and efficacy, four series (7, 12, 15, and 19) of 35 novel 4-aminopyrimidine derivatives were rationally designed and synthesized based on the binding site of ThDP in E. coli PDHc-E1. 12, 15, and 19 were confirmed to be potent inhibitors against E. coli PDHc-E1. Selected compounds 12g, 12i, 15f, and 19a showed negligible inhibition against porcine PDHc-E1. To understand their selectivity, the interaction of inhibitor and E. coli PDHc-E1 or porcine PDHc-E1 was studied by molecular docking. The newly introduced acylhydrazone and N-phenylbenzamide moieties could form stronger interaction by hydrogen bond at the active site of E. coli PDHc-E1 compared with that of porcine PDHc-E1. A part of title compounds as potent PDHc-E1 inhibitors also exhibited notable antibacterial activity. In particular, 12e, 12f, 12g, 12o, and 19a exhibited 72-92% inhibition against Xanthomonas oryzae pv. Oryzae and Ralstonia solanacearum at 100 µg/mL, which was better than thiodiazole-copper (34 and 29%, respectively) and bismerthiazol (56 and 55%, respectively). The results proved that we could obtain effective bactericidal compounds as highly selective PDHc inhibitors by rational molecular design utilizing the binding model of active site of E. coli PDHc-E1.

Synthesis and herbicidal activity of optically active α-(substituted phenoxyacetoxy) (substituted phenyl) methylphosphonates.

α-(Substituted phenoxyacetoxy) alkylphosphonates containing one chiral carbon atom have been demonstrated to be PDHc inhibitor with good herbicidal activity and some of them could be used as potential herbicide. In order to determine any difference in herbicidal activities between (R) and (S) isomers, the synthetic method of optically active substituted phenylalkylphosphonates IB were explored. A highly practical, enantioselective hydrophosphonylation was developed to prepare optically active O,O-dimethyl α-hydroxyalkylphosphonates 3 as key intermediate by asymmetric addition reaction of dimethylphosphite 1 and several kinds of aldehydes 2 using tridentate Schiff base Al(III) complexes as catalysts. A series of novel O,O-dimethyl α-(substituted phenoxyacetoxy)(substituted phenyl)methylphosphonates IB including (R) and (S) enantiomers were further synthesized with excellent enantioselectivity (95-99% ee) by the condensation of optically active α-hydroxyl (substituted phenyl)methylphosphonates 3 and substituted phenoxyacetyl chlorides 4. The herbicidal activities of title compound IB including their racemates, (R) and (S) enantiomers were evaluated in greenhouse for post-emergence application. All compounds IB showed significant inhibitory activity against dicotyledonous plants. A difference in herbicidal effect among racemate, (R) and (S) enantiomers were observed. Especially IB7 and IB10 showed obvious chiral selectivity in inhibitory activity against chickweed. (S)-IB7 with ED50 of 22.8gai/ha was found to be most effective enantiomer against chickweed and its inhibitory activity was 8.17 times higher than (R)-IB7. (S)-IB7 as potential herbicide would be effective at lower rates than (R)-IB7 or (rac)-IB7.

Design, Synthesis, and Potency of Pyruvate Dehydrogenase Complex E1 Inhibitors against Cyanobacteria.

Safe and effective algaecides are needed to control agriculturally and environmentally significant algal species. Four series (6, 10, 17, and 21) of 29 novel 4-aminopyrimidine derivatives were rationally designed and synthesized. A part of 10, 17, and 21 displayed potent inhibition of Escherichia coli pyruvate dehydrogenase complex E1 (E. coli PDHc-E1) (IC50 = 2.12-18.06 µM) and good inhibition of Synechocystis sp. PCC 6803 (EC50 = 0.7-7.1 µM) and Microcystis sp. FACH 905 (EC50 = 3.7-7.6 µM). The algaecidal activity of these compounds positively correlated with their inhibition of E. coli PDHc-E1. In particular, 21l and 10b exhibited potent algaecidal activity against PCC 6803 (EC50 = 0.7 and 0.8 µM, respectively), values that were 2-fold increased compared to that of copper sulfate (EC50 = 1.8 µM), and showed the best inhibition of cyanobacterium PDHc-E1 (IC50 = 5.10 and 6.06 µM, respectively). 17h and 21e, the best inhibitors of E. coli PDHc-E1, were studied by molecular docking, site-directed mutagenesis, and enzymatic assays. These results revealed that the improved inhibition of novel inhibitors compared with that of the lead compound I was due to the formation of a new hydrogen bond with Leu264 at the active site of E. coli PDHc-E1. The results proved the great potential to obtain effective algaecides via the rational design of PDHc-E1 inhibitors.

Design and optimization of N-acylhydrazone pyrimidine derivatives as E. coli PDHc E1 inhibitors: Structure-activity relationship analysis, biological evaluation and molecular docking study.

By targeting the thiamin diphosphate (ThDP) binding site of Escherichia coli (E. coli) pyruvate dehydrogenase multienzyme complex E1 (PDHc E1), a series of novel 'open-chain' classes of ThDP analogs A, B, and C with N-acylhydrazone moieties was designed and synthesized to explore their activities against E. coli PHDc E1 in vitro and their inhibitory activity against microbial diseases were further evaluated in vivo. As a result, A1-23 exhibited moderate to potent inhibitory activities against E. coli PDHc E1 (IC50=0.15-23.55µM). The potent inhibitors A13, A14, A15, C2, had strong inhibitory activities with IC50 values of 0.60, 0.15, 0.39 and 0.34µM against E. coli PDHc E1 and with good enzyme-selective inhibition between microorganisms and mammals. Especially, the most powerful inhibitor A14 could 99.37% control Xanthimonas oryzae pv. Oryzae. Furthermore, the binding features of compound A14 within E. coli PDHc E1 were investigated to provide useful insights for the further construction of new inhibitor by molecular docking, site-directed mutagenesis, and enzymatic assays. The results indicated that A14 had most powerful inhibition against E. coli PDHc E1 due to the establishment of stronger interaction with Glu571, Met194, Glu522, Leu264 and Phe602 at active site of E.coli PDHc E1. It could be used as a lead compound for further optimization, and may have potential as a new microbicide.

Synthesis and Herbicidal Activity of α-(Substituted Phenoxybutyryloxy or Valeryloxy)alkylphosphonates and 2-(Substituted Phenoxybutyryloxy)alkyl-5,5-dimethyl-1,3,2-dioxaphosphinan-2-one.

On the basis of our work on the modification of alkylphosphonates 1, a series of α-(substituted phenoxybutyryloxy or valeryloxy)alkylphosphonates (4-5) and 2-(substituted phenoxybutyryloxy)alkyl-5,5-dimethyl-1,3,2-dioxaphosphinan-2-one (6) were designed and synthesized. The bioassay results indicated that 14 of title compounds 4 exhibited significant postemergence herbicidal activity against velvetleaf, common amaranth, and false daisy at 150 g ai/ha. Compounds 5 were inactive against all tested weeds. Compounds 6 exhibited moderate to good inhibitory effect against the tested dicotyledonous weeds. Structure-activity relationship (SAR) analyses showed that the length of the carbon chain as linking bridge had a great effect on the herbicidal activity. Broad-spectrum tests of compounds 4-1, 4-2, 4-9, 4-30, and 4-36 were carried out at 75 g ai/ha. Especially, 4-1 exhibited 100% inhibition activity against the tested dicotyledonous weeds, which was higher than that of glyphosate.

Synthesis, antitumor activity and mechanism of action of novel 1,3-thiazole derivatives containing hydrazide-hydrazone and carboxamide moiety.

A series of novel 2,4,5-trisubstituted 1,3-thiazole derivatives containing hydrazide-hydrazine, and carboxamide moiety including 46 compounds T were synthesized, and evaluated for their antitumor activity in vitro against a panel of five human cancer cell lines. Eighteen title compounds T displayed higher inhibitory activity than that of 5-Fu against MCF-7, HepG2, BGC-823, Hela, and A549 cell lines. Especially, T1, T26 and T38 exhibit best cytotoxic activity with IC50 values of 2.21µg/mL, 1.67µg/mL and 1.11µg/mL, against MCF-7, BCG-823, and HepG2 cell lines, respectively. These results suggested that the combination of 1,3-thiazole, hydrazide-hydrazone, and carboxamide moiety was much favorable to cytotoxicity activity. Furthermore, the flow cytometry analysis revealed that compounds T1 and T38 could induce apoptosis in HepG2 cells, and it was confirmed T38 led the induction of cell apoptosis by S cell-cycle arrest.

Rational design, synthesis and biological evaluation of 1,3,4-oxadiazole pyrimidine derivatives as novel pyruvate dehydrogenase complex E1 inhibitors.

On the basis of previous study on 2-methylpyrimidine-4-ylamine derivatives I, further synthetic optimization was done to find potent PDHc-E1 inhibitors with antibacterial activity. Three series of novel pyrimidine derivatives 6, 11 and 14 were designed and synthesized as potential Escherichia coli PDHc-E1 inhibitors by introducing 1,3,4-oxadiazole-thioether, 2,4-disubstituted-1,3-thiazole or 1,2,4-triazol-4-amine-thioether moiety into lead structure I, respectively. Most of 6, 11 and 14 exhibited good inhibitory activity against E. coli PHDc-E1 (IC50 0.97-19.21 µM) and obvious inhibitory activity against cyanobacteria (EC50 0.83-9.86 µM). Their inhibitory activities were much higher than that of lead structure I. 11 showed more potent inhibitory activity against both E. coli PDHc-E1 (IC50<6.62 µM) and cyanobacteria (EC50<1.63 µM) than that of 6, 14 or lead compound I. The most effective compound 11d with good enzyme-selectivity exhibited most powerful inhibitory potency against E. coli PDHc-E1 (IC50=0.97 µM) and cyanobacteria (EC50=0.83 µM). The possible interactions of the important residues of PDHc-E1 with title compounds were studied by molecular docking, site-directed mutagenesis, and enzymatic assays. The results indicated that 11d had more potent inhibitory activity than that of 14d or I due to its 1,3,4-oxadiazole moiety with more binding position and stronger interaction with Lsy392 and His106 at active site of E. coli PDHc-E1.

Two novel herbicide candidates affect Arabidopsis thaliana growth by inhibiting nitrogen and phosphate absorption.

Both 2-[(2,4-dichlorophenoxy)acetoxy](methy)lmethyl-5,5-dimethyl-1,3,2-dioxaphosphinan-2-one (termed as IIa) and 2-[(4-chloro-2-methyl-phenoxy)-acetoxy](methyl)methyl-5,5-dimethyl-1,3,2-dioxaphosphinan-2-one (termed as IIr) are novel herbicide candidates that positively affect herbicidal activity via the introduction of a phosphorus-containing heterocyclic ring. This report investigated the mechanism of IIa and IIr on weed control in the model plant Arabidopsis thaliana at physiological, ultrastructural and molecular levels. IIa and IIr significantly inhibited the growth of A. thaliana and altered its root structure by inhibiting energy metabolism and lipid or protein biosynthesis. These compounds also significantly affected the absorption of nitrogen and phosphorus by down-regulating the transcripts of nitrate transporter-related genes, ammonium transporter-related genes and phosphorus transporter-related genes.

Synthesis and antifungal activity of 5-iodo-1,4-disubstituted-1,2,3-triazole derivatives as pyruvate dehydrogenase complex E1 inhibitors.

To identify new antifungal lead compound based on inhibitors of pyruvate dehydrogenase complex E1, a series of 5-iodo-1,4-disubstituted-1,2,3-triazole derivatives 3 were prepared and evaluated for their Escherichia coli PDHc-E1 inhibitory activity and antifungal activity. The in vitro bioassay for the PDHc-E1 inhibition indicated all the compounds exhibited significant inhibition against E. coli PDHc-E1 (IC50<21µM), special compound 3g showed the most potent inhibitory activity (IC50=4.21±0.11µM) and was demonstrated to act as a competitive inhibitor of PDHc-E1. Meanwhile, inhibitor 3g exhibited very good enzyme-selective inhibition of PDHc-E1 between pig heart and E. coli. The assay of antifungal activity showed compounds 3e, 3g, and 3n exhibited fair to good activity against Rhizoctonia solani and Botrytis cinerea even at 12.5µg/mL. Especially compound 3n (EC50=5.4µg/mL; EC90=21.1µg/mL) exhibited almost 5.50 times inhibitory potency against B. cinerea than that of pyrimethanil (EC50=29.6µg/mL; EC90=113.4µg/mL). Therefore, in this study, compound 3n was found to be a novel lead compound for further optimization to find more potent antifungal compounds as microbial PDHc-E1 inhibitors.

The design, synthesis and biological evaluation of novel thiamin diphosphate analog inhibitors against the pyruvate dehydrogenase multienzyme complex E1 from Escherichia coli.

Pyruvate dehydrogenase multienzyme complex E1 (PDHc E1) is a potential target enzyme when looking for inhibitors to combat microbial disease. In this study, we designed and synthesized a series of novel thiamin diphosphate (ThDP) analogs with triazole ring and oxime ether moieties as potential inhibitors of PDHc E1. Their inhibitory activities against PDHc E1 were examined both in vitro and in vivo. Most of the tested compounds exhibited moderate inhibitory activities against PDHc E1 (IC50 = 6.1-75.5 µM). The potent inhibitors 4g, 4h and 4j, had strong inhibitory activities with IC50 values of 6.7, 6.9 and 6.1 µM against PDHc E1 in vitro and with inhibition rates of 35%, 50% and 33% at 100 µg mL(-1) against Gibberella zeae in vivo, respectively. The binding mode of 4j to PDHc E1 was analyzed by a molecular docking method. Furthermore, the possible interactions of the important residues of PDHc E1 with compound 4j were examined by site-directed mutagenesis, enzymatic assays and spectral fluorescence studies. The theoretical and experimental results are in good agreement and suggest that compound 4j could be used as a lead compound for further optimization, and may have potential as a new microbicide.