Novel Pyridyl-Oxazole Carboxamides: Toxicity Assay Determination in Fungi and Zebrafish Embryos.

Eight novel pyridyl-oxazole carboxamides were evaluated against fungi and displayed good fungicidal activities against Botrytis cinereal and Rhizoctonia solani. Preliminary bioassay results indicated that at 100 mg/L, compounds 6a-6e, 6g and 6h exhibited 100% fungicidal activities against Botrytis cinerea, and the compound 6b to Rhizoctonia solani at 100%. Then, the zebrafish embryo acute toxicity test was performed to assess the toxicity of 6b and 6c. A series of malformations appeared, when the zebrafish embryos were exposed to 6b and 6c, such as delayed yolk sac resorption, significant shortening of body length, pericardial edema, bending spine, lack of melanin, heart hemorrhage, head hemorrhage, delayed swim sac development, yolk malformation and head malformation. In addition, the acute toxicity of 6b to zebrafish embryo is 4.878 mg/L, and 6c is 6.257 mg/L.

CaSBP11 Participates in the Defense Response of Pepper to Phytophthora capsici through Regulating the Expression of Defense-Related Genes.

Squamosa promoter binding protein (SBP)-box genes are plant-specific transcription factors involved in plant growth and development, morphogenesis and biotic and abiotic stress responses. However, these genes have been understudied in pepper, especially with respect to defense responses to Phytophthora capsici infection. CaSBP11 is a SBP-box family gene in pepper that was identified in our previous research. Silencing CaSBP11 enhanced the defense response of pepper plants to Phytophthora capsici. Without treatment, the expression of defense-related genes (CaBPR1, CaPO1, CaSAR8.2 and CaDEF1) increased in CaSBP11-silenced plants. However, the expression levels of these genes were inhibited under transient CaSBP11 expression. CaSBP11 overexpression in transgenic Nicotiana benthamiana decreased defense responses, while in Arabidopsis, it induced or inhibited the expression of genes in the salicylic acid and jasmonic acid signaling pathways. CaSBP11 overexpression in sid2-2 mutants induced AtNPR1, AtNPR3, AtNPR4, AtPAD4, AtEDS1, AtEDS5, AtMPK4 and AtNDR1 expression, while AtSARD1 and AtTGA6 expression was inhibited. CaSBP11 overexpression in coi1-21 and coi1-22 mutants, respectively, inhibited AtPDF1.2 expression and induced AtPR1 expression. These results indicate CaSBP11 has a negative regulatory effect on defense responses to Phytophthora capsici. Moreover, it may participate in the defense response of pepper to Phytophthora capsici by regulating defense-related genes and the salicylic and jasmonic acid-mediated disease resistance signaling pathways.

One-pot asymmetric synthesis of a spiro[dihydrofurocoumarin/pyrazolone] scaffold by a Michael addition/I2-mediated cyclization sequence.

An asymmetric formal one-pot reaction of 4-hydroxycoumarins with unsaturated pyrazolones has been developed by merging a chiral bifunctional organocatalyst with molecular iodine, which furnished a series of optically active spiro[dihydrofurocoumarin/pyrazolone] heterocycles with spiro quaternary stereogenic centers in moderate to excellent yields (up to 99%) with excellent diastereoselectivities (up to >99 : 1 dr) and good to excellent enantioselectivities (up to 99% ee). The application in the gram-scale synthesis of chiral spiro[dihydrofurocoumarin/pyrazolone] compounds was also successfully realized.

Reduced tolerance to abiotic stress in transgenic Arabidopsis overexpressing a Capsicum annuum multiprotein bridging factor 1.

BACKGROUND: The pepper fruit is the second most consumed vegetable worldwide. However, low temperature affects the vegetative development and reproduction of the pepper, resulting in economic losses. To identify cold-related genes regulated by abscisic acid (ABA) in pepper seedlings, cDNA representational difference analysis was previously performed using a suppression subtractive hybridization method. One of the genes cloned from the subtraction was homologous to Solanum tuberosum MBF1 (StMBF1) encoding the coactivator multiprotein bridging factor 1. Here, we have characterized this StMBF1 homolog (named CaMBF1) from Capsicum annuum and investigated its role in abiotic stress tolerance. RESULTS: Tissue expression profile analysis using quantitative RT-PCR showed that CaMBF1 was expressed in all tested tissues, and high-level expression was detected in the flowers and seeds. The expression of CaMBF1 in pepper seedlings was dramatically suppressed by exogenously supplied salicylic acid, high salt, osmotic and heavy metal stresses. Constitutive overexpression of CaMBF1 in Arabidopsis aggravated the visible symptoms of leaf damage and the electrolyte leakage of cell damage caused by cold stress in seedlings. Furthermore, the expression of RD29A, ERD15, KIN1, and RD22 in the transgenic plants was lower than that in the wild-type plants. On the other hand, seed germination, cotyledon greening and lateral root formation were more severely influenced by salt stress in transgenic lines compared with wild-type plants, indicating that CaMBF1-overexpressing Arabidopsis plants were hypersensitive to salt stress. CONCLUSIONS: Overexpression of CaMBF1 in Arabidopsis displayed reduced tolerance to cold and high salt stress during seed germination and post-germination stages. CaMBF1 transgenic Arabidopsis may reduce stress tolerance by downregulating stress-responsive genes to aggravate the leaf damage caused by cold stress. CaMBF1 may be useful for genetic engineering of novel pepper cultivars in the future.

Prolinethiol ether catalysis in an asymmetric Michael reaction: solvent-free synthesis of functionalized monohaloalkenes.

The organocatalytic Michael reaction of ketones with γ-monohalonitrodienes catalyzed by chiral prolinethiol ether under solvent-free conditions was developed. The described method represents a novel approach for accessing highly functionalized monohaloalkenes with α, ß-stereocenters of up to >99% ee.

(2E,4E)-2-Cyano-5-dipropyl-amino-N,N-dimethyl-penta-2,4-dienamide.

In the title compound, C(14)H(23)N(3)O, the n-propyl group is disordered over two orientations with an occupancy ratio of 0.778 (3):0.222 (3). In the crystal, mol-ecules are linked by pairs of weak C-H⋯O inter-actions into inversion dimers with an R(2) (2)(14) graph-set motif.

Metagenomic analysis of the dynamical conversion of photosynthetic bacterial communities in different crop fields over different growth periods.

Photosynthetic bacteria are beneficial to plants, but knowledge of photosynthetic bacterial community dynamics in field crops during different growth stages is scarce. The factors controlling the changes in the photosynthetic bacterial community during plant growth require further investigation. In this study, 35 microbial community samples were collected from the seedling, flowering, and mature stages of tomato, cucumber, and soybean plants. 35 microbial community samples were assessed using Illumina sequencing of the photosynthetic reaction center subunit M (pufM) gene. The results revealed significant alpha diversity and community structure differences among the three crops at the different growth stages. Proteobacteria was the dominant bacterial phylum, and Methylobacterium, Roseateles, and Thiorhodococcus were the dominant genera at all growth stages. PCoA revealed clear differences in the structure of the microbial populations isolated from leaf samples collected from different crops at different growth stages. In addition, a dissimilarity test revealed significant differences in the photosynthetic bacterial community among crops and growth stages (P<0.05). The photosynthetic bacterial communities changed during crop growth. OTUs assigned to Methylobacterium were present in varying abundances among different sample types, which we speculated was related to the function of different Methylobacterium species in promoting plant growth development and enhancing plant photosynthetic efficiency. In conclusion, the dynamics observed in this study provide new research ideas for the detailed assessments of the relationship between photosynthetic bacteria and different growth stages of plants.

[Acupuncture improves cognitive function of vascular dementia rats by regulating PI3K/Akt/mTOR pathway].

OBJECTIVE: To explore the mechanism of acupuncture in improving cognitive ability by regulating hippocampal phosphatidylinositol-3 kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway in vascular dementia (VD) rats. METHODS: A total of 80 male SD rats were randomized into sham operation, model, non-acupoint and acupoint groups (n=18 per group). The VD model was established by ligation of the bilateral common carotid arteries. For rats of the acupoint group, "Baihui" (GV20) and bilateral "Zusanli "(ST36) were needled and stimulated by twirling the needles with reinforcing method, and for rats of the non-acupoint group, the bilateral subcostal spots (about 10 mm superior to the iliac cresta) were needled and stimulated by twirling the needles with uniform reinforcing and reducing method. The treatment was conducted once daily, 6 times a week for two weeks, beginning 3 days after successful modeling. Rats of the sham operation group and model group received grasps as those in the acupoint groups. Morris water maze test was used to detect the abilities of learning and spatial memory. The contents of reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD) and the activities of acetylcholinesterase (AChE) and acetylcholine transferase (ChAT) in the hippocampus tissue were detected by using ELISA, changes of hippocampal mitochondrial membrane potential (MMP) detected using JC-1 fluorescence probe, and the expression levels of hippocampal phosphorylated (p)-PI3K, p-Akt and mTOR proteins measured using Western blot. RESULTS: Compared with the sham operation group, the escape latency, contents of ROS and MDA, and AChE activity were significantly increased (P<0.05), and the spatial memory ability, SOD activity, ChAT activity, MMP, p-PI3K, p-Akt and mTOR expression levels were significantly decreased in the model group (P<0.05). Compared with the model group, carotid artery ligature-induced increase of the escape latency, contents of ROS and MDA, and AChE activity, and decrease of the spatial memory ability, SOD activity, ChAT activity, MMP, p-PI3K, p-Akt and mTOR expression levels were significantly reversed in the acupuncture group (P< 0.05), but not in the non-acupoint group (P>0.05). The therapeutic effects of acupoint needling were obviously superior to those of non-acupoint needling in decreasing the escape latency, contents of ROS and MDA, and AChE activity (P<0.05), and in increasing the spatial memory ability, SOD activity, ChAT activity, MMP, p-PI3K, p-Akt and mTOR expre-ssion levels (P<0.05). CONCLUSION: Acupuncture can improve cognitive function of VD rats, which may be related with its functions in easing oxidative stress and MMP reduction by activating PI3K/Akt/mTOR signaling pathway in the hippocampus.

Enantioselective Syntheses of C2-Symmetric Pyrazolones and Diones via One-Pot Organo-/Iodine Sequential Catalysis.

The catalytic diastereo- and enantioselective syntheses of C2-symmetric axially chiral 1,4-dicarbonyl derivatives with 2,3-quaternary stereocenters were achieved by utilizing an organo-/iodine binary catalytic strategy. The reactions proceeded well under mild conditions without metals or strong bases.

Kresoxim-methyl Derivatives: Synthesis and Herbicidal Activities of (Pyridinylphenoxymethylene)phenyl Methoxyiminoacetates.

A series of new kresoxim-methyl derivatives, (pyridinylphenoxymethylene)phenyl methoxyiminoacetates, were synthesized and their structures were confirmed by NMR and high-resolution mass spectrometry (HRMS). Although derived from a fungicide, the bioassays indicated that several new compounds had good herbicidal activities. At 37.5 g a.i./ha, compound 5c showed 100% inhibition against Abutilon theophrasti, Amaranthus retroflexus, and Eclipta prostrata, which was better than mesotrione. Compound 5e had a broad herbicidal spectrum against broadleaf weeds. The present work indicates that 5c and 5e may serve as new candidates for potential herbicides.

Characterization and expression profile of CaNAC2 pepper gene.

The plant-specific NAC (NAM, ATAF, and CUC) transcription factors have diverse role in development and stress regulation. A new transcript encoding NAC protein, homologous to nam-like protein 4 from Petunia was identified from an ABA-regulated subtractive cDNA library of Capsicum annuum seedling. Here, this homolog (named CaNAC2) from C. annuum was characterized and investigated its role in abiotic stress tolerance. Our results indicated that a plant-specific and conserved NAC domain was located in the N-terminus domain of CaNAC2 which was predicted to encode a polypeptide of 410 amino acids. Phylogenetic analysis showed that CaNAC2 belonged to the NAC2 subgroup of the orthologous group 4d. The protein CaNAC2 was subcellularly localized in the nucleus and it had transcriptional activity in yeast cell. CaNAC2 was expressed mainly in seed and root. The transcription expression of CaNAC2 was strongly induced by cold, salt and ABA treatment and inhibited by osmotic stress and SA treatment. Silence of CaNAC2 in virus-induced gene silenced pepper seedlings resulted in the increased susceptibility to cold stress and delayed the salt-induced leaf chlorophyll degradation. These results indicated that this novel CaNAC2 gene might be involved in pepper response to abiotic stress tolerance.

Pd(OAc)2-catalyzed regioselective aromatic C-H bond fluorination.

A novel Pd(OAc)2-NFSI-TFA system was developed for the highly selective ortho-monofluorination directed by diverse aryl-N-heterocyclic directing groups e.g., quinoxaline, pyrazole, benzo[d]oxazole, and pyrazine derivatives. A Pd(II/IV) catalytic cycle was proposed based on the ESI-MS/MS studies.