Dissipation, accumulation, distribution and risk assessment of fungicides in greenhouse and open-field cowpeas.

Pesticide residues in cowpeas have raised worldwide concern. However, only a few studies have focused on pesticide accumulation and distribution in greenhouse and open-field cowpeas. Field trial results suggest that difenoconazole, dimethomorph, thifluzamide and pyraclostrobin dissipated faster in open fields (mean half-lives, 1.72-1.99 days) than in greenhouses (2.09-3.55 days); moreover, fungicide residues in greenhouse cowpeas were 0.84-8.19 times higher than those in the open-field cowpeas. All fungicides accumulated in the greenhouse and open-field cowpeas after repeated spraying. Fungicide residues in old cowpeas were higher than those in tender cowpeas, and residues in the upper halves of cowpea pods were higher than those in the lower halves. In addition, cowpeas distributed in the lower halves of the plants had higher fungicide residues. Our findings suggest that greenhouse cultivation contributed to the pesticide residues in cowpeas after repeated spraying, although the levels of dietary health risks remained acceptable under both cultivation scenarios.

The widespread presence of triazole fungicides in greenhouse soils in Shandong Province, China: A systematic study on human health and ecological risk assessments.

Triazole fungicides (TFs) are extensively used on greenhouse vegetables and are ubiquitously detected in the environment. However, the human health and ecological risks associated with the presence of TFs in the soil are unclear. In this study, ten widely used TFs were measured in 283 soil samples from vegetable greenhouses across Shandong Province, China, and their potential human health and ecological risks were assessed. Among all soil samples, difenoconazole, myclobutanil, triadimenol, and tebuconazole were the top detected TFs, with detection rates of 85.2-100%; these TFs had higher residues, with average concentrations of 5.47-23.8 µg/kg. Although most of the detectable TFs were present in low amounts, 99.3% of the samples were contaminated with 2-10 TFs. Human health risk assessment based on hazard quotient (HQ) and hazard index (HI) values indicated that TFs posed negligible non-cancer risks for both adults and children (HQ range, 5.33 × 10-10 to 2.38 × 10-5; HI range, 1.95 × 10-9 to 3.05 × 10-5, <1). Ecological risk assessment based on the toxicity exposure ratio (TER) and risk quotient (RQ) values indicated that difenoconazole was a potential risk factor for soil organisms (TERmax = 1 for Eisenia foetida, <5; RQmean = 1.19 and RQmax = 9.04, >1). Moreover, 84 of the 283 sites showed a high risk (RQsite range, 1.09-9.08, >1), and difenoconazole was the primary contributor to the overall risk. Considering their ubiquity and potential hazards, TFs should be continuously assessed and prioritized for pesticide risk management.

Cyclic loading test study on a new cast-in-situ insulated sandwich concrete wall.

Insulated sandwich concrete panel (ISCP) is widely used because of its high thermal insulation efficiency and low construction cost. Aiming at improving traditional ISCP, a new cast-in-situ concrete wall structure made of ISCP is proposed, which is composed of thin-walled cold-formed steels, slant steel wire connectors, steel wire meshes, concrete layers, expanded polystyrene sheets and reinforced concrete embedded columns. In order to assess the hysteretic properties of the new insulated sandwich concrete wall and the influence of various parameters, low-frequency horizontal cyclic load tests were carried out on seven full-scale specimens of new type cast-in-situ insulated sandwich concrete wall. The specimens were compared and analyzed with respect to failure mode, bearing capacity, ductility, degradation characteristics and energy dissipation capacity. The results show that the final failure pattern of the specimen is two main diagonal cracks intersecting each other; the bearing capacity is greatly affected by concrete thickness and axial compression ratio, regardless of concrete strength. Brittle failure is typically observed when the steel wire spacing is large, while ductility is pronounced when the concrete layer thickness is small and the concrete strength is low; the smaller the thickness of concrete layer, the faster the stiffness degrades. The wall structure shows a better energy dissipation performance with a smaller steel wire spacing, lower concrete strength and smaller axial compression ratio.

TcMYC2a, a Basic Helix-Loop-Helix Transcription Factor, Transduces JA-Signals and Regulates Taxol Biosynthesis in Taxus chinensis.

The multitherapeutic taxol, which can be obtained from Taxus spp., is the most widely used anticancer drug. Taxol biosynthesis is significantly regulated by jasmonate acid (JA), one of the most important endogenous hormones in land plants. Nevertheless, the JA-inducing mechanism remains poorly understood. MYC2 is one of the key regulators of JA signal transfer and the biosynthesis of various secondary metabolites. Here, TcMYC2a was identified to contain a basic helix-loop-helix (bHLH)-leucine zipper domain, a bHLH-MYC_N domain, and a BIF/ACT-like domain. TcMYC2a was also found to bind with TcJAZ3 in yeast, which was a homolog of Arabidopsis JASMONATE ZIM-domain JAZ proteins, indicating that TcMYC2a had a similar function to AtMYC2 of JA signal transduction. TcMYC2a was able to affect the expression of GUS reporter gene by binding with the T/G-box, G-box, and E-box, which were the key cis-elements of TASY and TcERF12/15 promoter. TcMYC2a overexpression also led to significantly increased expression of TASY, tat, dbtnbt, t13h, and t5h genes. Additionally, TcERF15, which played the positive role to regulate tasy gene, was up-regulated by TcMYC2a. All these results revealed that TcMYC2a can regulate taxol biosynthesis either directly or via ERF regulators depending on JA signaling transduction.

Transcriptome-wide identification and screening of WRKY factors involved in the regulation of taxol biosynthesis in Taxus chinensis.

WRKY, a plant-specific transcription factor family, plays important roles in pathogen defense, abiotic cues, phytohormone signaling, and regulation of plant secondary metabolism. However, little is known about the roles, functions, and mechanisms of WRKY in taxane biosynthesis in Taxus spp. In this study, 61 transcripts were identified from Taxus chinensis transcriptome datasets by using hidden Markov model search. All of these transcripts encoded proteins containing WRKY domains, which were designated as TcWRKY1-61. After phylogenetic analysis of the WRKY domains of TcWRKYs and AtWRKYs, 16, 8, 10, 14, 5, 7, and 1 TcWRKYs were cladded into Group I, IIa-IIe, and III, respectively. Then, six representative TcWRKYs were selected to classify their effects on taxol biosynthesis. After MeJA (methyl jasmonate acid) and SA (salicylic acid) treatments, all of the six TcWRKYs were upregulated by MeJA treatment. TcWRKY44 (IId) and TcWRKY47 (IIa) were upregulated, whereas TcWRKY8 (IIc), TcWRKY20 (III), TcWRKY26 (I), TcWRKY41 (IIe), and TcWRKY52 (IIb) were downregulated by SA treatment. Overexpression experiments showed that the six selected TcWRKYs exerted different effects on taxol biosynthesis. In specific, TcWRKY8 and TcWRKY47 significantly improved the expression levels of taxol-biosynthesis-related genes. Transcriptome-wide identification of WRKY factors in Taxus not only enhances our understanding of plant WRKY factors but also identifies candidate regulators of taxol biosynthesis.

Polyhydric polymer-loaded pyrene composites as powerful adsorbents and fluorescent probes: highly efficient adsorption and test strips-based fluorimetric analysis of curcumin in urine and plant extracts.

Polyhydric poly (vinyl alcohol) was covalently loaded with a 1-pyrenecarboxyaldehyde fluorophore. The yielded PVA-Pyr composites can serve as powerful adsorbents and strong fluorescent probes for the highly efficient adsorption and sensitive fluorimetric detection with test strips of curcumin in samples of urine and plant extracts.

Transcriptome Assembly and Systematic Identification of Novel Cytochrome P450s in Taxus chinensis.

Taxus spp. is a highly valuable medicinal plant with multiple pharmacological effects on various cancers. Cytochrome P450s (CYP450s) play important roles in the biosynthesis of active compounds in Taxus spp., such as the famous diterpenoid, Taxol. However, some specific CYP450 enzymes involved in the biosynthesis of Taxol remain unknown, and the systematic identification of CYP450s in Taxus has not been reported. In this study, 118 full-length and 175 partial CYP450 genes were identified in Taxus chinensis transcriptomes. The 118 full-length genes were divided into 8 clans and 29 families. The CYP71 clan included all A-type genes (52) belonging to 11 families. The other seven clans possessed 18 families containing 66 non-A-type genes. Two new gymnosperm-specific families were discovered, and were named CYP864 and CYP947 respectively. Protein sequence alignments revealed that all of the T. chinensis CYP450s hold distinct conserved domains. The expression patterns of all 118 CYP450 genes during the long-time subculture and MeJA elicitation were analyzed. Additionally, the expression levels of 15 novel CYP725 genes in different Taxus species were explored. Considering all the evidence, 6 CYP725s were identified to be candidates for Taxol biosynthesis. The cis-regulatory elements involved in the transcriptional regulation were also identified in the promoter regions of CYP725s. This study presents a comprehensive overview of the CYP450 gene family in T. chinensis and can provide important insights into the functional gene studies of Taxol biosynthesis.