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In this paper, we construct a uniform formula for the Riemann solutions of the simplified Chapman-Jouguet model. Firstly, we define a new functional, and then, we obtain that the Riemann solutions can be expressed by the maximum value point of this functional, while Riemann solutions may contain some of strong detonation waves, Chapman-Jouguet detonation waves and contact discontinuities. Finally, Chapman-Jouguet deflagration waves are also discussed.

Aiming to discover novel high-efficient antifungal leads that possess an innovative action mechanism, twenty-three carboxylated pyrroline-2-one derivatives, bearing a phenylhydrazine moiety, were rationally designed and firstly prepared in this letter. The in vitro bioassays showed that most of the compounds possessed excellent antifungal effects with the EC50 values of less than 1 μg/mL against the phytopathogenic fungi Fusarium graminearum (Fg), Botrytis cinerea (Bc), Rhizoctonia solani (Rs) and Colletotrichum capsici (Cc). The further bioassays showed that the compound 6u showed the comparable in vivo control effect with carbendazim against fusarium head blight and rice sheath blight. The 3D-QSAR model revealed the pivotal effects of a bulky electron-donating group at the 1-position of pyrrole ring, a bulky electron-withdrawing group at the 4-position of phenyl ring and a small alkyl at the carbonate group on the anti-Rs activities of target compounds. The abnormal mycelial morphology and delayed spore germination were observed in the treatments of compound 6u. Given the excellent and broad-spectrum antifungal effects the target compounds have, we unfeignedly anticipated that the above finding could motivate the discovery of high-efficient antifungal leads, which might possess an innovative action mechanism against phytopathogenic fungi.

Background Tenuazonic acid (TeA), a putative nonhost-selective mycotoxin isolated from Alternaria alternata, is the main causative agent of brown leaf spot disease of crofton weed (Ageratina adenophora) and some other crops. Previous studies revealed that it is a natural photosystem II inhibitor that binds the D1 protein to block electron transfer. Though the crude metabolite extract of A. alternata containing TeA has been bioassayed, the herbicidal activity of synthesized TeA has not been systematically evaluated yet. Results TeA caused leaves of crofton weed to have brown spots that were more pronounced in older leaves than younger ones. It completely killed 92% of the four-leaf seedlings at 600 g ai/ha but only 81% or less of six-leaf seedlings or bigger. The bioassay of phytotoxicity of TeA to 67 plant species including 54 weeds and 13 crops, showed that TeA had a broad weed spectrum but low toxicity to Solanaceae and Malvaceae species. Further potted- plant experiments demonstrated that TeA had EC90 values that ranged from 119 to 795 μg/mL for 14 important weeds but was 2539 μg/mL for Acalypha australis. Nicotiana tabacum and Gossypium hirsutum had no injury symptoms at 1000 μg/mL. A field trial showed that TeA effectively controlled two important weeds, Digitaria sanguinalis and Amaranthus retroflexus without affecting cotton in the field. Conclusion TeA has potential as a biobased herbicide for controlling important dicotyledon and monocotyledon weeds in cotton and tobacco fields. © 2019 Society of Chemical Industry.

Substituted phenylhydrazone moieties and two carbonate groups were merged in one molecule scaffold to obtain 48 novel compounds. 1H and 13C NMR, MS, elemental analysis, and X-ray single-crystal diffraction were used to confirm their structures. Bioassay results revealed that some of the compounds have strong antifungal activities against Botrytis cinerea, Rhizoctonia solani, and Colletotrichum capsici (especially Rhizoctonia solani). Compound 5H1 is the most promising of the tested compounds against R. solani with an EC50 value of 1.91 mg/L, which is comparable with the positive control fungicide drazoxolon (1.94 mg/L). The structure-activity relationships against R. solani formed three rules: 1) small carbonate groups may improve the antifungal activity of the title compounds; 2) electron-withdrawing groups at the phenyl ring of phenylhydrazone are preferable to their non-substituted counterparts; and 3) halogen at the para position is more beneficial than at the ortho or meta position.

A series of novel 2-(6-thioxo-1,3,5-thiadiazinan-3-yl)-N′-phenylacethydrazide derivatives were designed, synthesized and evaluated for their antifungal activities against Fusarium graminearum (Fg), Rhizoctonia solani (Rs), Botrytis cinerea (Bc) and Colletotrichum capsici (Cc). The bioassay results in vitro showed that most of the title compounds exhibited impressive antifungal activities against the above plant fungi. Particularly, the compounds 5c, 5f, 5g, 5i, 5m and 5p displayed desirable anti-Rs activities, with the corresponding EC50 values of 0.37, 0.32, 0.49, 0.50, 0.46 and 0.45 µg/mL, respectively, which are superior to the positive control carbendazim (0.55 µg/mL). Further in vivo bioassay results showed that the anti-Rs activity of title compound 5f at 200 µg/mL reached 95.84% on detached rice leaves and 93.96% on rice plants. Featuring convenient synthesis, novel structures and desirable antifungal activity, these 2-(6-thioxo-1,3,5-thiadiazinan-3-yl)-N′-phenylacethydrazide derivatives could be further studied as the potential candidates of novel agricultural fungicides.

Background Tetramic acid, thiophene and hydrazone derivatives were found to exhibit favorable antifungal activity. Aiming to discover novel template molecules with potent antifungal activity, a series of novel 3-(thiophen-2-yl)-1,5-dihydro-2H-pyrrol-2-one derivatives containing a hydrazone group were designed, synthesized, and evaluated for their antifungal activity. Results The structures of 3-(thiophen-2-yl)-1,5-dihydro-2H-pyrrol-2-one derivatives bearing a hydrazone group were confirmed by FT-IR, 1H NMR, 13C NMR, 1H-1H NOESY, EI-MS and elemental analysis. Antifungal assays indicated that some title compounds exhibited antifungal activity against Fusarium graminearum (Fg), Rhizoctorzia solani (Rs), Botrytis cinerea (Bc) and Colletotrichum capsici (Cc) in vitro. Strikingly, the EC50 value of 5e against Rs was 1.26 µg/mL, which is better than that of drazoxolon (1.77 µg/mL). Meanwhile, title compounds 5b, 5d, 5e–5g, 5n–5q and 5t exhibited remarkable anti-Cc activity, with corresponding EC50 values of 7.65, 9.97, 6.04, 6.66, 7.84, 7.59, 9.47, 5.52, 6.41 and 7.53 µg/mL, respectively, which are better than that of drazoxolon (19.46 µg/mL). Conclusions A series of 3-(thiophen-2-yl)-1,5-dihydro-2H-pyrrol-2-one derivatives bearing a hydrazone group were designed, synthesized and evaluated for their antifungal activity against Fg, Rs, Bc and Cc. Bioassays indicated that some target compounds exhibited obvious antifungal activity against the above tested fungi. These results provide a significant basis for the further structural optimization of tetramic acid derivatives as potential fungicides. Electronic supplementary material The online version of this article (10.1186/s13065-018-0452-z) contains supplementary material, which is available to authorized users.

A series of novel fused heterocyclic compounds bearing benzo[4,5]imidazo[1,2-d][1,2,4]triazine 4a–4w were designed and conveniently synthesized via the intermediates 2-(halogenated alkyl)-1H-benzo[d]imidazoles 2a, 2b, and 2-((1-(substituted phenyl)hydrazinyl)alkyl)-1H-benzo[d]imidazoles 3a–3g. The structures of all target compounds were characterized by FT-IR, 1H NMR, 13C NMR, and EI-MS, of which, the structure of compound 4n was further determined by the single crystal X-ray diffraction. The crystal structure of 4n was crystallized in the triclinic crystal system, space group P 1 ¯ with a = 9.033 (6) A, b = 10.136 (7) A, c = 10.396 (7) A, α = 118.323 (7)°, β = 91.750 (8)°, γ = 104.198 (7)°, Z = 2, V = 800.2 (9) A3; total R indices: R1 = 0.0475, wR2 = 0.1284. The antifungal activity of title compounds 4a–4w in vitro against the phytopathogenic fungi Botrytis cinerea (B. cinerea), Rhizoctonia solani (R. solani) and Colletotrichum capsici (C. capsici) were evaluated, the bioassay results demonstrated that most of the title compounds exhibited obvious fungicidal activities at 50 μg/mL. This work indicated that benzo[4,5]imidazo[1,2-d][1,2,4]triazine derivatives could be considered as a new leading structure in searching for novel agricultural fungicides.

Additional file 1. All the copies of FT-IR, 1H NMR, 13C NMR and EI-MS for title compounds 5aâ 5w.

A series of novel 6-(sec-butyl)-3-methyl-1-(substituted phenyl)-5,6- dihydropyrrolo[3,4-c]pyrazol-4-(1H)ones 5a–h were synthesized using L-isoleucine methyl ester hydrochloride as the starting material. Their structures were characterized by 1H NMR, FT-IR, EI-MS and elemental analysis. Compound 5f was further analyzed by single-crystal X-ray diffraction. The bioassay results indicate that most of the compounds exhibit inhibitory activity against four plant pathogenic fungi Fusarium graminearum, Botrytis cinerea, Rhizoctonia cerealis and Colletotrichum capsici.

A series of novel 3-(2-(substituted phenyl)hydrazinylmethylidene)furan-2,4(3H,5H)-diones were designed and synthesized with ethyl 4-chloroacetoacetate as the starting material. Their structures were confirmed by FT-IR, 1H NMR, 13C NMR, EI-MS and elemental analysis. Bioassay data demonstrated that these compounds exhibited remarkable antifungal activity against Fusarium graminearum, Botrytis cinerea, Rhizoctonia cerealis and Colletotrichum capsici. Compound 3-(2-(4-bromophenyl)hydrazinylmethylidene)furan-2,4(3H,5H)-dione (5g) had excellent bioactivity against Botrytis cinerea with an EC50 value of 0.18 μg/mL - markedly lower than the 0.24 μg/mL of the commercial fungicide procymidone. The result revealed that introducing the halogenated phenylhydrazine at the 3-position of furan-2,4(3H, 5H)-dione was an effective way to design new tetronic acid derivatives as new fungicides.

Twenty-seven novel pyrrolidine-2,4-dione derivatives containing N-substituted phenylhydrazine moiety were synthesized. Their structures were confirmed by 1H NMR, 13C NMR and MS. The half effective concentration (EC50) values of the title compounds against the phytopathogenic fungi Rhizoctonia cerealis were evaluated. Compounds 6l and 6q displayed good bioactivity with EC50 values of 1.626 and 2.043 μg/mL, respectively. The 3D quantitative structure activity relationship(3D-QSAR) model of CoMFA was established with reliable cross-validated correlation coefficient q 2 value of 0.585 and Noncross-validated correlation coefficient r 2 value of 0.971. This model provided a tool for guiding further design and synthesis of novel pyrrolidine-2,4-dione derivatives with high fungicidal activity.

( E )-Methyl-2-(2-(bromomethyl)phenyl)-3-methoxyacrylate was reacted with substituted 1-acetylpyrrolidine-2,4-diones and 3-(1-(hydroxylamino)ethylidene)pyrrolidine-2,4-diones respectively to synthesize two series of β -methoxyacrylate derivatives containing the pyrrolidine-2,4-dione moiety. The structures of the targeted compounds were confirmed by IR, 1 H NMR, 13 C NMR, MS and elemental analysis. The fungicidal activity against Rhizoctonia solani , Botrytis cinerea and Fusarium graminearum was evaluated. The bioassay results demonstrated that these compounds showed visible fungicidal activity.

For the aim of discovering new fungicide, a series of phenylpyrrole-substituted tetramic acid derivatives bearing carbonates 6a-q were designed and synthesized via 4-(2,4-dioxopyrrolidin-3-ylidene)-4-(phenylamino)butanoic acids 4a-k and the cyclized products 1',3,4,5'-tetrahydro-[2,3'-bipyrrolylidene]-2',4',5(1H)-triones 5a-k. The compounds were characterized using IR, ¹H- and (13)C-NMR spectroscopy, mass spectrometry (EI-MS), and elemental analysis. The structure of 6b was confirmed by X-ray diffraction crystallography. The title compounds 6a-q were bioassayed in vitro against the phytopathogenic fungi Fusarium graminearum, Botrytis cinerea and Rhizoctonia solani at a concentration of 100 μg/mL, respectively. Most compounds displayed good inhibitory activity.

3-Acetyl-5-isopropyltetramic acid (3-AIPTA), a derivate of tetramic acid, is responsible for brown leaf-spot disease in many plants and often kills seedlings of both mono- and dicotyledonous plants. To further elucidate the mode of action of 3-AIPTA, during 3-AIPTA-induced cell necrosis, a series of experiments were performed to assess the role of reactive oxygen species (ROS) in this process. When Arabidopsis thaliana leaves were incubated with 3-AIPTA, photosystem II (PSII) electron transport beyond Q(A) (the primary plastoquinone acceptor of PSII) and the reduction of the end acceptors at the PSI acceptor side were inhibited; this was followed by increase in charge recombination and electron leakage to O(2), resulting in chloroplast-derived oxidative burst. Furthermore, the main antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) lost their activity. Excess ROS molecules directly attacked a variety of cellular components and subsequently caused electrolyte leakage, lipid peroxidation and cell membrane disruption. Finally, this led to cell destruction and leaf tissue necrosis. Thus, 3-AIPTA-triggered leaf necrosis of Arabidopsis was found to be a result of direct oxidative injury from the chloroplast-originated ROS burst initiated by the inhibition of normal photosynthetic electron transport.

3-Acetyl-5-isopropyltetramic acid (3-AIPTA), an analogue of the phytotoxin tenuazonic acid, is a tetramic acid derivate. It is demonstrated here that 3-AIPTA is a multi-target inhibitor of root and shoot growth as well as photosynthesis. Based on fast chlorophyll fluorescence kinetics, 3-AIPTA blocks electron transport beyond QA on the acceptor side of PSII by competing with QB for the QB-binding site, but does not affect the donor side and the light harvesting function of the PSII antenna. Additionally, higher 3-AIPTA concentration also inhibits the reduction of end acceptors of PSI. Evidences from JIP-test and competitive replacement with [14C]atrazine showed that 3-AIPTA, like tenuazonic acid, does not share the same binding environment with the atrazine-like PSII inhibitors although they possess the common action target of the QB-site. It is deduced that tetramic acid families of natural products, where 3-AIPTA and tenuazonic acid belong to, is a novel inhibitor type of the photosynthetic electron transport chain.

A series of N-(2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl)thiocarbamates were synthesized by the reaction of glucosyl isothiocyanates with monohydric and dihydric alcohols, and acetone oxime, using methods of both normal reaction and microwave-assisted synthesis. Antifungal activities of the title compounds were determined with three kinds of plant pathogenic fungi, Fusarium graminearum, Rhizoctoria cerealis, and Colletotrichum orbiculare. The synthesized glucosyl thiocarbamates easily reacted with HgCl(2) to give novel metal-organic compounds, bis[O-alkyl N-(2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl)thiocarbamato]mercury, in yields of 80%. This strong affinity of thiocarbamates for mercury showed their potential utility in medical or marine environmental detoxification.

Among the title compounds, derivative (Vb) shows excellent bioactivity with an EC50 value markedly lower than the commercial fungicide procymidone.

Aim Successful hematopoietic stem cell transplantation (HSCT) requires accurate allele-level matching of donor and recipient HLA genes. To improve accuracy, we implemented next-generation DNA sequencing (NGS) methods for high-resolution HLA genotyping of HSCT patients and donors. Here we evaluate NGS HLA typing accuracy and the effect on clinical management of HSCT patients. Methods NGS genotyping for HLA-A, -B, -C, -DRB1, -DRB3/4/5, -DQA1, -DQB1, -DPA1, and -DPB1 was performed on peripheral blood ( n = 151) and buccal swab ( n = 7) samples for HSCT patients and potential donors between November 2016 and March 2017 using TruSight HLA v2, Nextera XT Index, and MiSeq Nano v2 300 cycle reagents (Illumina). Phased exon sequence data were analyzed using Assign TruSight v2 software. Results HLA typing by NGS resulted in unambiguous allele-level genotyping of 2739/2826 (96.9%) alleles tested. Ambiguities were primarily (71.3%) in DPB1 with inability to discriminate between G group alleles differing in exon 1 or the 5’ UTR. One DPB1 allele had non-G group ambiguity. In 19 alleles ( DRB1, DRB3/4/5, DQA1, DPA1, DPB1 ) no 100% sequence match could be identified in the IMGT reference database. NGS enabled confident identification of 24 non-CWD alleles ( B, DRB1, DPB1 ). The potential clinical impact of this improved accuracy was evaluated by re-analysis of NGS sequencing results using only non-phased DNA sequence for class I exons 2, 3, and 4, and class II exons 2 and 3 to simulate expected results from Sanger-based DNA typing. De-resolution of NGS data for 62 unrelated donors demonstrated ambiguity in 57% of alleles tested. NGS efficiently integrated into the clinical workflow with an average TAT of 5 days and 90.5% of samples meeting the 7 day TAT goal. Buccal swab samples presented difficulty, as 5/7 had to be repeated using increased DNA concentrations to account for DNA degradation. Repeat sequencing successfully genotyped 4/5 buccal swab samples. Conclusions NGS methodology provides significantly improved ability to accurately and unambiguously type HLA genes. Typing accuracy is primarily limited by incomplete reference gene DNA sequence and difficulty in generating full-gene sequence including exon 1 and the 5’ UTR for class II genes.

HLA typing of donors for solid organ transplantation is performed with the primary goal of avoiding hyperacute antibody-mediated rejection (AMR) caused by recipient antibodies against donor antigens. Given the need for rapid testing of deceased donors, SSP or SSO methods are used to enable timely HLA typing at the serologic split antigen level. However, these methods do not provide unambiguous allele-level genotyping. This ambiguity can be problematic in patients with allele-specific anti-HLA antibodies. We report a case of suspected AMR following deceased donor kidney transplantation as an example of high-resolution HLA genotyping enabling identification of donor-specific antibodies (DSA). The patient was transplanted in 2010 with a flow cytometric crossmatch negative deceased donor kidney. History was remarkable for biopsy-proven C4d positive acute AMR in 2012 successfully treated by IVIG and rituximab. In late 2016, the patient developed increased proteinuria. Biopsy demonstrated changes consistent with both active and chronic AMR, but without presence of C4d. Solid-phase anti-HLA antibody testing did not demonstrate identifiable DSA, though there was evidence of allele-specific antibodies (Table 1). To investigate whether these represented DSA, donor DNA was re-typed for HLA-A, -B, -C, -DRB1, -DRB3/4/5, -DQA1, -DQB1, -DPA1,and -DPB1 by next-generation DNA sequencing (NGS). High-resolution HLA typing identified DSA against DQA1∗05:05 and DRB3∗03:01. Reactivity against DR52 or DQA05 would not have been called based upon average group reactivity. Identification of DSA supported diagnosis of AMR and enabled tracking of DSA as an objective measure of the efficacy of therapy. The increasing frequency of allele-specific DSA has led us to implement routine re-testing of solid organ donors for high-resolution HLA typing to promote accurate and efficient evaluation of potential allele-specific DSA. Download : Download high-res image (123KB) Download : Download full-size image

A series of 3-(1-(2-(substituted phenyl)hydrazinyl)alkylidene)furan-2,4(3H,5H)-diones were designed and prepared using two synthetic routes. Their structures were confirmed by FT-IR, (1)H NMR, (13)C NMR, MS, elemental analysis and single-crystal X-ray diffraction. Their bioactivity was evaluated against Botrytis cinerea in vitro. Most target compounds exhibited remarkable antifungal activity. Two compounds 7f and 7h were highly effective and their EC50 values were 0.241 μg/mL and 0.167 μg/mL, respectively, close to that of the control drug procymidone. 3D-QSAR studies of CoMFA and CoMSIA were carried out. Models with good predictive ability were generated with the cross validated q(2) values for CoMFA and CoMSIA being 0.565 and 0.823. Conventional r(2) values were 0.983 and 0.945, respectively. The results provided a practical tool for guiding the design and synthesis of novel and more potent tetronic acid derivatives containing substituted phenylhydrazine moiety.

Aimed at the external disturbing force of a hydraulic servo system, the paper designs a feed-forward disturbance compensator Based on the principle of structure fixity. A control law is designed by applying the augmented linear quadratic regulator (ALQR), which makes the hydraulic servo system follow the ideal position signal quickly and well. Eventually, the simulation result shows that this method possesses the good performance.

Aim The revised kidney allocation system (KAS) implemented to increase opportunity for highly sensitized (>98% cPRA) patients awaiting deceased donor kidney transplantation has significantly increased organ offers for these patients. Concomitantly, we observed an increase in unexpectedly positive cellular crossmatches not predicted by virtual crossmatch (VCXM). We hypothesized that unexpected crossmatches were concentrated among highly sensitized patients and resulted from technical factors of alloantibody testing limiting VCXM efficacy. Methods Histocompatibility testing results were analyzed pre-KAS (12/2013 – 11/2014) and KAS (12/2014 – 12/2015) for living (pre-KAS n = 76, KAS n = 103) and deceased donor (pre-KAS n = 277, KAS n = 375) kidney transplantation. Cellular crossmatch was performed by flow cytometry (FCXM). Anti-HLA antibody testing was performed using LABScreen Single Antigen Bead (SAB) assay, with mfi >3,000 used as VCXM cutoff for identifying alloantibodies expected to cause positive FCXM. Results KAS implementation increased FCXM performed for highly sensitized patients for deceased donor kidney transplantation (6.0% vs. 1.1%) with increased unexpected positive FCXM (13.9% vs. 10.1%). Similar trends were not observed for living donors. Highly sensitized patients accounted for 29.4% of VCXM failures. Patients with cPRA 80–97% or>98% showed significant deviation from VCXM performance characteristics. Root cause analysis of unexpected FCXM results ( n = 79) demonstrated that only 31.7% were due to limitations in UNET (unlisted avoid antigens, allelic antibodies, or antibodies against HLA-DP). Technical limitations including positive FCXM from multiple weak DSA (21.5%), false negative SAB due to prozone (7.6%), and non-HLA antibodies (11.4%) were responsible for a majority of definable VCXM failures. Patients with cPRA >80% accounted for 70.0% of technical VCXM failures (excluding non-HLA) despite being only 12.4% of tests performed. Conculsions New KAS policy significantly increases deceased donor kidney offers to highly sensitized patients. While VCXM is highly useful for organ allocation, highly sensitized patients present significant challenge in accurate prediction of compatibility warranting prospective cellular crossmatching to ensure optimal outcomes.

Twenty novel metal complexes M(1)(cis-L)(2)Y(2), M(1)(trans-L)(2)Y(2,) M(2)(cis-L)(4)Y(2), and M(2)(trans-L)(4)Y(2) (M(1) = Zn(II), Co(II), Cu(II); M(2) = Mn(II), Ni(II); Y = OAc, Cl, ClO(4), and NO(3)) were synthesized by reacting bivalent transitional metal salt MY(2).nH(2)O (n = 0-6) with ligands cis-racemate of propiconazole (cis-L) and trans-racemate of propiconazole (trans-L), respectively. All of these synthesized complexes were identified by atomic absorption spectrometry, elemental analysis, and IR and UV spectra. The cumulative release studies of some selected complexes in static water were performed; all determined complexes were found to exhibit attractive controlled release properties, yet the ligand release rates of cis-L complexes were slower than those of trans-L complexes. Meanwhile, it was found that the release rate of ligand cis-L from representative complex Zn(cis-L)(2)Cl(2) was affected obviously by different conditions, such as temperature, pH, and PVA film coating. The antifungal activities of the ligands and their complexes against five selected plant pathogenic fungi were evaluated; the results demonstrated that the toxicity of cis-L was 3.39-5.95 times greater than that of trans-L, and all of the synthesized complexes showed superior activities of 1.19-6.36 times to those of their ligands, especially Zn complexes having toxicities 2.62-6.36 times greater than those of their ligands. Moreover, the cis-L complexes had more sensitive activities than their relevant trans-L complexes; for example, Zn(cis-L)(2)Cl(2) appeared to be 5.00-8.67 times stronger than Zn(trans-L)(2)Cl(2) complex. In addition, the mechanism of increased antifungal activities of the title complexes in comparison with their ligands was discussed preliminarily.

Tenuazonic acid (TeA) is a natural phytotoxin produced by Alternaria alternata, the causal agent of brown leaf spot disease of Eupatorium adenophorum. Results from chlorophyll fluorescence revealed TeA can block electron flow from QA to QB at photosystem II acceptor side. Based on studies with D1-mutants of Chlamydomonas reinhardtii, the No. 256 amino acid plays a key role in TeA binding to the QB-niche. The results of competitive replacement with [14C]atrazine combined with JIP-test and D1-mutant showed that TeA should be considered as a new type of photosystem II inhibitor because it has a different binding behavior within QB-niche from other known photosystem II inhibitors. Bioassay of TeA and its analogues indicated 3-acyl-5-alkyltetramic and even tetramic acid compounds may represent a new structural framework for photosynthetic inhibitors.