Artemisia argyi allelopathy: a generalist compromises hormone balance, element absorption, and photosynthesis of receptor plants.

BACKGROUND: Allelopathy is expressed through the release of plant chemicals and is considered a natural alternative for sustainable weed management. Artemisia argyi (A. argyi) is widely distributed throughout Asia, and often dominates fields due to its strong allelopathy. However, the mechanism of A. argyi allelopathy is largely unknown and need to be elucidated at the physiological and molecular levels. RESULTS: In this study, we used electron microscopy, ionomics analysis, phytohormone profiling, and transcriptome analysis to investigate the physiological and molecular mechanisms of A. argyi allelopathy using the model plant rice (Oryza sativa) as receptor plants. A. argyi water extract (AAWE)-treated rice plants grow poorly and display root morphological anomalies and leaf yellowing. We found that AAWE significantly inhibits rice growth by destroying the root and leaf system in multiple ways, including the integrity of ultrastructure, reactive oxygen species (ROS) homeostasis, and the accumulation of soluble sugar and chlorophyll synthesis. Further detection of the hormone contents suggests that AAWE leads to indole-3-acetic acid (IAA) accumulation in roots. Moreover, ionomics analysis shows that AAWE inhibits the absorption and transportation of photosynthesis-essential mineral elements, especially Mg, Fe, and Mn. In addition, the results of transcriptome analysis revealed that AAWE affects a series of crucial primary metabolic processes comprising photosynthesis in rice plants. CONCLUSIONS: This study indicates that A. argyi realizes its strongly allelopathy through comprehensive effects on recipient plants including large-scale IAA synthesis and accumulation, ROS explosion, damaging the membrane system and organelles, and obstructing ion absorption and transport, photosynthesis and other pivotal primary metabolic processes of plants. Therefore, AAWE could potentially be developed as an environmentally friendly botanical herbicide due to its strong allelopathic effects.

[Identification, biological characterization, and fungicide screening of pathogen causing southern blight in Aster tataricus].

This study aims to clarify the species and biological characteristics of the pathogen causing southern blight in Aster tataricus and screen out effective fungicides for the prevention and control of this disease. We collected the typical diseased plants and sclerotia on soil surface for the isolation of the pathogen, and identified the pathogen based on morphological characteristics, molecular biological characteristics, and pathogenicity. Further, we evaluated the inhibitory effects of 12 fungicides on the pathogen by plate growth inhibition assay. In the diseased plants, watery brown spots first appeared at the stem base and then spread upward, which were covered with white mycelia and surrounded by white to yellow-brown sclerotia. From the diseased plants, 15 strains with consistent traits were isolated. The pathogen was identified as Athelia rolfsii based on morphological characteristics and ITS and TEF sequences. The pathogenicity test was carried out according to Koch's rule, which showed the disease symptoms consistent with those in the field. The pathogen presented the optimum growth at 28-30 ℃, pH 5-8, and full darkness. The preliminary indoor screening demonstrated that four chemical fungicides(taifujin, hymexazol, flusilazole, and lime-sulphur-synthelic-solution), two botanical fungiticides(ethylicin and garlic oil), and a microbial agent(Bacillus subtilis) had good inhibitory effects on A. rolfsii. The results of gradient inhibition experiments showed that B. subtilis, flusilazole, and ethylicin had stronger inhibitory activity. The further in vivo screening indicated that ethylicin can be used as the main fungicide for the prevention and treatment of southern blight in A. tataricus.

Danqi soft caspule prevents atrial fibrillation by ameliorating left atrial remodeling through inhibiting cardiac fibroblasts differentiation and function.

BACKGROUND: Danqi soft capsule (DQ) is a Chinese herb medicine with a remarkable protective effect on cardio-cerebrovascular diseases. PURPOSE: The study aimed to investigate the role and mechanism of DQ on left atrial (LA) remodeling and atrial fibrillation (AF) occurrence in rats with post-myocardial infarction (MI) induced heart failure (HF). METHODS: MI in rats was established by ligation of the left anterior descending coronary artery. DQ was administered to the post-MI induced HF rats over a 4-week period. AF inducibility was detected using the transesophageal programmed electrical stimulation technology. Echocardiogram, histology, and western blot analysis were performed. Meanwhile, cardiac fibroblasts (CFs) were performed to determine the effects of DQ on CFs function by 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT), flow cytometry, transwell assay and ELISA. RESULTS: The DQ-treated rats showed lower rates of AF inducibility and shorter AF durations than the MI rats. Moreover, DQ inhibited fibrosis and increased the expression of Cx43 in the left atrium; it also inhibited the myofibroblasts differentiation by reducing the expression of cytokines TNF-α, IL-6, and TGF-ß1 via the TGF-ß1/Smad 3 pathway. In addition, DQ inhibited the proliferation, migration, and collagen secretion of CFs in vitro. CONCLUSIONS: DQ reduces the risk of AF in post-MI HF rats by ameliorating LA arrhythmogenic substrate via inhibiting the function of proliferation, migration, collagen secretion, and myofibroblasts differentiation of CFs. Together, these results indicate the therapeutic potential of DQ in AF by delaying the progression of LA remodeling in post-MI-induced HF. Targeting CFs may be a novel prospective therapeutic avenue for AF after MI.

Weed Suppression and Molecular Mechanisms of Isochlorogenic Acid A Isolated from Artemisia argyi Extract via an Activity-Guided Method.

Allelopathy is considered an environmentally friendly and resource-conserving approach to weed control because allelochemicals degrade easily and cause less pollution than traditional chemical herbicides. In this study, the allelopathic active constituents of Artemisia argyi were elucidated by activity-guided isolation and ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS). First, a crude extract prepared in water was fractionated using macroporous resin D101 to obtain three fractions (Fr.A-C). Combined with the allelopathic activity assay on Setaria viridis and Portulaca oleracea, Fr.C was determined to be the most active fraction. We identified 14 compounds in the active fraction (Fr.C) using UPLC-QTOF-MS, including 13 phenolic compounds. Accordingly, phenolic components have been suggested as the main allelochemicals in A. argyi. Thereafter, Fr.C was further isolated by octadecylsilyl (ODS) chromatography to obtain eight subfractions (Fr.C-1-Fr.C-8). Finally, isochlorogenic acid A (ICGAA) was purified from Fr.C-3 by semipreparative liquid chromatography, which was detected in the growth environment of A. argyi. Furthermore, we evaluated the allelopathic effects of ICGAA on six weeds from different families and genera for the first time. The results showed that ICGAA is a novel allelochemical with broad herbicidal activity. In addition, we analyzed the inhibitory effect and molecular mechanism of ICGAA on the growth of S. viridis seedlings. Optical microscopy and transmission electron microscopy (TEM) revealed the degradation of membrane structures and organelles after ICGAA treatment. Transcriptome and real-time polymerase chain reaction (RT-qPCR) analysis showed that ICGAA inhibited the growth of weeds mainly by inhibiting the diterpenoid biosynthesis pathway (especially gibberellins, GAs). The decrease of gibberellin (GA) contents after ICGAA treatment also confirmed these results. In brief, this study provides new material sources and theoretical support for developing biological herbicides for agroecosystems.

The role of antifungal activity of ethyl acetate extract from Artemisia argyi on Verticillium dahliae.

AIMS: This study investigated the antifungal activity and mechanisms of ethyl acetate extract of Artemisia argyi (EAAA) against Verticillium dahliae. METHODS AND RESULTS: Optical and scanning electron microscopy observation showed that 2.0 mg ml-1 EAAA treatment reduced spore germination rate to 4.56%. Histochemical staining showed that 2.0 mg ml-1 EAAA treatment increased reactive oxygen species (ROS) by more than two times. Physiological test showed that EAAA treatment decreased the contents of soluble proteins and sugars, and reduced the activities of malate dehydrogenase and succinate dehydrogenase by nearly half. Transcriptome analysis showed that EAAA treatment down-regulated the expression of genes involved in primary metabolic pathways of V. dahliae. CONCLUSIONS: Our results revealed that EAAA inhibited the growth and development of V. dahliae from multiple levels and multiple targets, including inhibiting the germination and development of V. dahliae spores, destroying the structure of cell membranes, inducing ROS burst, reducing the activities of respiratory-related enzymes and down-regulating the expression of genes in primary metabolic pathways. SIGNIFICANCE AND IMPACT OF THE STUDY: The mechanism of the multitarget effects of EAAA against V. dahliae may limit the potential of fungus developing resistance and provide the efficient methods to control verticillium wilt disease in the future.

Study of nitrogen removal efficiency of the filled bed reactors using alkali-treated corncobs-sulfur (mixotrophic) for treating the effluent from simulated urban wastewater plants.

China's urban wastewater treatment plants' nitrogen discharge standards have become more stringent in recent years. In this experiment, the filled bed denitrification system with corncob-sulfur as fillers were constructed for the secondary effluent of the wastewater. The optimum operating conditions of the denitrification reactor with different fillers as electron donors were investigated by varying the operating parameters. According to the experiment, the alkali pretreated corncobs could maintain long-term denitrification effect. The optimum HRT for the mixotrophic denitrification reactor with alkali-treated corncob-sulfur as filler was 1.5 h, with a minimum effluent NO3--N concentration of 0.31 mg/L and a removal rate of 98.62%, and effluent nitrite nitrogen, NH4+-N, and sulfate accumulation of 0.03 mg/L, 0.71 mg/L and 72.4 mg/L. The reactor with mixed nutrient type had the most abundant species community structure by high-throughput sequencing analysis.

[Identification,biological characteristics and fungicide screening of pathogen of southern blight in Cynanchum stauntonii].

During the high-temperature and rainy season from June to October in 2017-2019,serious southern blight broke out in the Cynanchum stauntonii planting area in Tuanfeng county,Hubei province,which had a great impact on the yield and quality of medicinal materials. In this study,the pathogen of C. stauntonii was isolated,purified,and identified,and the pathogenicity was tested according to Koch's postulates. Meanwhile,the biological characteristics of the pathogen were analyzed. On this basis,the effective fungicides were screened in laboratory. Finally,the pathogen( BQ-1) was identified as Athelia rolfsii( Deuteromycotina,Basidiomycota,anamorph: Sclerotium rolfsii). The optimum growth conditions for BQ-1 were 25-30 ℃,p H 5-8,and alternating light and dark.The effective chemical fungicides were lime-sulphur-synthelic-solution( LSSS) and flusilazole,and the effective botanical fungicide was osthole. BQ-1 was highly homologous to the pathogen HS-1 of peanut southern blight,with the similarity of 18 S r DNA and TEF sequences at 99. 09%. The southern blight in C. stauntonii might be resulted from that in peanut. In the production of C. stauntonii,the following measures should be taken: avoiding rotation or neighboring with peanut,draining water from June to October to reduce humidity,and reasonably applying fungicides.

Comparison of Chemical Constituents and Pharmacological Effects of Different Varieties of Chrysanthemum Flos in China.

Chrysanthemum Flos is the prestigious traditional Chinese medicinal material and the popular health drink. This article comprehensively evaluated the chemical constituents, antioxidant activity, and hepatoprotective effects of 25 common chrysanthemum varieties in China. Firstly, we analyzed the chemical compositions of water extracts of chrysanthemum using UPLC/Q-TOF-MS, and identified 29 chemical components. The results displayed that chrysanthemum was rich in chemical constituents, but there were significant differences in the contents of four phenolic acids and five flavonoids among different varieties, and the coefficient of variation (CVs) ranged from 35.96 % to 114.62 %. Then, the antioxidant activities of different chrysanthemums were investigated, respectively via 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), and Ferric Reducing Antioxidant Power (FRAP) assays. The spectrum-effect relationships between nine main components and antioxidant activities were investigated to identify the antioxidant constitutes in chrysanthemums. Meanwhile, H2 O2 -induced hepatocyte injury testing showed wide variation in cultivar antioxidant capacity, with Tongchengju (TCJ) producing the best effect (90.32 %), followed by Chuju (CJ; 85.78 %). In addition, the hepatoprotective effects of 8 mainstream varieties were determined by the model of acute alcoholic liver injury. They protected liver from injury by affecting relevant liver function and antioxidant indexes. Huangshangongju (HSG) could decrease aspartate aminotransferase (AST) activity by 39.27 % in liver tissue; Hangju-Fubaiju (HJ-FBJ), Jinsihuangju (JSH), and Chuju (CJ) significantly decreased the malondialdehyde (MDA) content of liver tissue, which reduced by more than 40 %; Jinsihuangju (JSH) of used for tea could double the content of glutathione (GSH) and had the similar effect on superoxide dismutase (SOD) as the positive group, showing significant antioxidant capacity. Therefore, this study confirmed that chrysanthemums are potential resources as antioxidants, functional foods, and medicinal materials. Importantly, it may provide a scientific support for further development and utilization of chrysanthemum, and screen excellent varieties for different demands.

Transfer characteristic of fluorine from atmospheric dry deposition, fertilizers, pesticides, and phosphogypsum into soil.

Fluorine (F) is widely dispersed in the environment and frequently used in industry and agriculture with a high migration ability. Thus, it is essential to understand the leaching characteristic of F in soil from industry and agriculture sources. Several sources of F pollutants in soil, including fertilizers, pesticides, phosphogypsum, and atmospheric deposition, were selected to investigate leaching characteristics of F in soil by leaching experiments. The addition of phosphate fertilizer and compound fertilizer (N:P:K = 20:10:15) enhanced the leachability of F in soil and the proportion of F leached out from soil treated by these fertilizers were 0.25% and 0.24%, respectively. However, unanticipated lower leachability of F appeared in compound fertilizer (N:P:K = 17:17:17), nitrogen fertilizer, dipterex, fluoroglycofen, fluopimomide, simulative dry deposition (YF3), and phosphogypsum loaded soils compared with additive-absent treatment. Although phosphogysum had a high F concentration, minimum proportion of F released (0.18%) was observed in phosphogypsum-coverd soil. The amounts of F leaching-out from surface soils (0-25 cm) treated with nitrogen fertilizer decreased 1.03 kg ha-1 comparing with blank control. Soil with phosphate fertilizer leached 5.47 kg F ha-1 a year, having the highest environment risk to deeper soil and groundwater. However, phosphogypsum and dry deposition of airbone F chemical had few effects on F leaching in soil. F-containing materials from agricultural process may leach more F from surface soils than industrial sources.

Allelopathic effect of Artemisia argyi on the germination and growth of various weeds.

Allelopathy means that one plant produces chemical substances to affect the growth and development of other plants. Usually, allelochemicals can stimulate or inhibit the germination and growth of plants, which have been considered as potential strategy for drug development of environmentally friendly biological herbicides. Obviously, the discovery of plant materials with extensive sources, low cost and markedly allelopathic effect will have far-reaching ecological impacts as the biological herbicide. At present, a large number of researches have already reported that certain plant-derived allelochemicals can inhibit weed growth. In this study, the allelopathic effect of Artemisia argyi was investigated via a series of laboratory experiments and field trial. Firstly, water-soluble extracts exhibited the strongest allelopathic inhibitory effects on various plants under incubator conditions, after the different extracts authenticated by UPLC-Q-TOF-MS. Then, the allelopathic effect of the A. argyi was systematacially evaluated on the seed germination and growth of Brassica pekinensis, Lactuca sativa, Oryza sativa, Portulaca oleracea, Oxalis corniculata and Setaria viridis in pot experiments, it suggested that the A. argyi could inhibit both dicotyledons and monocotyledons not only by seed germination but also by seedling growth. Furthermore, field trial showed that the A. argyi significantly inhibited the growth of weeds in Chrysanthemum morifolium field with no adverse effect on the growth of C. morifolium. At last, RNA-Seq analysis and key gene detection analysis indicated that A.argyi inhibited the germination and growth of weed via multi-targets and multi-paths while the inhibiting of chlorophyll synthesis of target plants was one of the key mechanisms. In summary, the A. argyi was confirmed as a potential raw material for the development of preventive herbicides against various weeds in this research. Importantly, this discovery maybe provide scientific evidence for the research and development of environmentally friendly herbicides in the future.

First Report of Leaf Spot on White Chrysanthemum (Chrysanthemum morifolium) Caused by Epicoccum sorghinum in Hubei province, China.

White Chrysanthemum (Chrysanthemum morifolium), a perennial herb of the Compositae family, is used for traditional medicine. The planting area of white chrysanthemum in Macheng city, Hubei Province is about 3333 ha and the annual output can reach more than 5000 tons. In 2019, leaf spot disease appeared on almost all middle and lower leaves of white chrysanthemum in most fields of Fengshumiao county, Macheng city (N31°29'57″, E115°05'49″). This county has 33 acres white chrysanthemum planting area, and most of the plants in the county were infected with the leaf spot disease. The average incidence of leaf spot disease was 65%, and incidence in some areas was 100%. In our observations, leaf spot disease can occur throughout the whole growth period of white chrysanthemum, and it will become more serious under the high temperature and humidity condition. Usually, the diseased leaves account for 30 to 80% of the total leaves on the plant. Leaf spot initially manifests as necrotic lesions on the edge and tip of the leaf, and then the lesions coalesce and gradually expand to form irregular light-brown to brown-black spots, eventually leading to necrosis and curling of the entire leaf. This disease seriously affects the growth and development of plants, resulting in the decline of yield and quality of white chrysanthemum. Ten symptomatic leaf samples were collected, the surfaces were disinfected with 0.1% mercuric chloride (HgCl2) for 3 min, and washed with sterile distilled water three times. Ten tissue samples at the junction of diseased and healthy areas (0.5 × 0.5 cm2) were cut and placed on potato dextrose agar (PDA) medium containing 100 µg/ml cefotaxime sodium and incubated in a dark chamber at 28°C. After 2 days, the hyphal tips from the edges of growing colonies were transferred to fresh PDA plates for further purification. Finally, eight isolates were obtained and these isolates were similar in morphology. The color of purified isolates was initially white to pale yellow. After six days of incubation, colonies had a diameter of 8 cm and the cultures were pale gray and starting to secrete scarlet pigment. After 15 days incubation, the colonies were grayish brown, while the backside was reddish-brown. Gray to tan chlamydospores were observed, nearly spherical, with a wart-like surface. Unicellular chlamydospores were 7.91 to 32.23 × 12.03 to 38.42 µm (n=30) and multicellular chlamydospores were 6.32 to 25.10 × 21.75 to 100.05 µm (n=30). The morphological characteristics were similar to Epicoccum sorghinum (Kang et al. 2019). The isolate FDY-5 was chosen for molecular identification. The sequence of rDNA-ITS, TUB, and LSU of the FDY-5 were amplified (GenBank MT800929, MT799852, and MT800935, respectively) (White et al. 1990; Carbone and Kohn 1999; Lumbsch et al. 2000). BLAST results showed that the rDNA-ITS sequences, the TUB gene sequences, and LSU gene sequences of strain FDY-5 shared 99% identity with the sequences of E. sorghinum (syn. Phoma sorghina) in GenBank (MN555348.1, MF987525.1, MK516207.1, respectively). Moreover, a phylogenetic tree of the LSU gene sequence of FDY-5 was constructed based on the Neighbor-Joining (NJ) method in MEGA6 software (Tamura et al. 2013) and revealed that strain FDY-5 was closest to E. sorghinum. Based on morphological and molecular characteristics, the fungus was identified as E. sorghinum. Pathogenicity tests were conducted on two-month-old white chrysanthemum plants. The upper three leaves of three plants were randomly selected for stab treatment and were inoculated with 5 × 5 mm mycelial discs produced from a fifteen-day-old colony on PDA. The inoculated and control (treated with sterile PDA disks) plants were incubated in a moist chamber (25 ± 2 °C, RH 85%). The first lesions appeared 1 day after inoculation on leaves, and the necrotic lesion area expanded outward and showed typical symptoms 3 days later. To fulfill Koch's postulates, the pathogen was reisolated from nine inoculated leaves by repeating the above isolating operation, and confirmed as E. sorghinum by morphology. To the best of our knowledge, this is the first report of E. sorghinum causing leaf spot on white chrysanthemum in China. E. sorghinum has a wide host range worldwide and often causes crop yield reduction. This report will facilitate the diagnosis of white chrysanthemum leaf spot of white chrysanthemum allowing control measures to be adopted to manage this disease in a timely manner. References Carbone, I., and Kohn, L. M. 1999. Mycologia 91:553. Kang, Y., et al. 2019. Plant Dis. 103 (7):1787. Lumbsch, H., et al. 2000. Plant Biol. 2:525. Tamura, K., et al. 2013. Mol. Biol. Evol. 30:2725-2729. White, T. J., et al. 1990. Page 315 in:PCR protocols:a guide to methods and applications. Academic Press, San Diego, CA. Funding Funding was supported by Major Increase and Decrease Projects at the Central Level of China (2060302) and the National Key Research and Development Program (2017FYC1700704).

[Allelopathic effects of Miscanthus floridulus on seed germination and seedling growth of three crops]. / å·´èŒ è‰æ°´æµ¸ææ¶²å¯¹3种作物种子萌发及幼苗生长的化感作用.

Allelopathic effects of Miscanthus floridulus at different growth stages on Brassica peki-nensis, Lactuca sativa, and Oryza sativa were examined using six parameters of seed germination and seedling growth, including germination rate, germination speed index, germination index, root length, stem length, and biomass. The results showed that the allelopathic effects of M. floridulus leaf extract were stronger than that of stem extract, with the germination index and biomass of reci-pient plants treated by leaf extract being significantly lower than those treated by stem extract. The allelopathic effect of M. floridulus in the withering stage was stronger than that in the vigorous growth stage. There was a significant dose-effect relationship between the concentrations of leaf extract and the allelopathic effects on three different receptor plants. The higher the extract concentration was, the stronger the allelopathic inhibition was. Leaf extract of M. floridulus could completely inhibit all the germination indices of B. pekinensis and L. sativa at the concentrations of 0.075 and 0.10 g·mL-1, respectively. The inhibition rates of 0.10 g·mL-1 leaf extract on germination rate, germination speed index, and germination index of O. sativa were 13.8%, 27.2% and 19.3%, respectively. Leaf extract of M. floridulus could completely inhibit all the growth indices of B. pekinensis and L. sativa at the concentrations of 0.05 and 0.10 g·mL-1, respectively. However, the inhibition rates of 0.10 g·mL-1 leaf extract on root length, stem length, and biomass of O. sativa were 64.6%, 92.9% and 21.8%, respectively. In summary, according to the comprehensive allelopathy response index (SE) of seed germination and seedling growth, the susceptibility of the three tested species to the extracts of M. floridulus was B. pekinensis (Cruciferae) > L. sativa (Compositae) > O. sativa (Gramineae).

Chinese Medicine She-Xiang-Xin-Tong-Ning, Containing Moschus, Corydalis and Ginseng, Protects from Myocardial Ischemia Injury via Angiogenesis.

The Chinese patent medicine She-Xiang-Xin-Tong-Ning (SXXTN) is a clinical medication for coronary heart disease (CHD) and angina pectoris. This study aimed to investigate pharmacological effects of SXXTN and elucidate the role in angiogenesis on human umbilical vein endothelial cells (HUVECs) and acute myocardial ischemia (AMI) rats. We prepared SXXTN to treat the cells to reveal their effects on oxidative stress-damaged cell viability, as well as cell proliferation, migration, and tube formation processes. SXXTN was also used to treat coronary artery ligation-induced acute myocardial ischemia rats to confirm whether it had positive effect on myocardial issues by hematoxylin and eosin (HE), 2,3,5-triphenyltetrazolium chloride (TTC) staining and immunohistochemical staining. We measured the levels of peroxidative damage-related enzymes in cytoplasm and serum by biochemical kits and detected vascular endothelial growth factor (VEGF), angiotensin II (Ang II), thromboxane B2 (TXB2), and 6-keto-prostaglandin F1 alpha (6-keto-PGF1α) levels in cells and rats by enzyme-linked immunosorbent assay (ELISA) kits. The results showed that SXXTN protects HUVECs against oxidative stress damage and reversed the decrease of superoxide dismutase (SOD), glutathione (GSH) and increase of creatine kinase (CK), lactate dehydrogenase (LDH) caused by oxidative stress. SXXTN promoted angiogenesis through stimulating cell migration, tube formation, and activating VEGF/VEGFR2 and ERK1/2 pathways. Furthermore, SXXTN reduced infarct size and inhibited PGI2/TXA2 imbalance, preventing atherosclerosis plaque rupture leading to worsening coronary heart disease. Taken together, we report the first in vivo and in vitro evidence that SXXTN reduced oxidative stress-mediated damage and enhanced angiogenesis, which might be useful in treatment of myocardial infarction.

Distribution, health risk assessment, and anthropogenic sources of fluoride in farmland soils in phosphate industrial area, southwest China.

The high concentration of fluoride (F) in soils has become a rising concern for its toxicity to microbes, plants, animals and human health. In the present study, the spatial and vertical distribution, health risk assessment and anthropogenic sources of F in farmland soils in an industrial area dominated by phosphate chemical plants were studied. Concentrations of total fluoride (TF) and water soluble fluoride (WSF) in the surface soils decreased with distance within the range of 2500 m at the prevailing downwind of the industrial area. The soil TF and WSF concentrations in 0-40 cm profiles were higher than those in 40-100 cm layers in the industrial area. At the prevailing downwind of the industrial area within 700 m, the hazard quotient values of human exposure to surface soils were higher than 1, indicating that a potential risk may exist for human health in this area. The main exposure pathway for children and adults was oral ingestion and particulate inhalation, respectively. The source apportionment model of soil F was modified based on years' historical data and experimental data. The results showed that the proportion of anthropogenic sources of soil F was dustfalls (69%) > irrigation water (23%) > air (5%) > chemical fertilizers (3%) in the industrial area. The high F concentration of dustfalls was mainly due to the phosphate rock, phosphogypsum, and surface soils with high F contents from the factories. In order to safeguard human health and alleviate hazards of F to surroundings, the control of pollutants emission from factories was a basic and vital step to reduce F in the soils in industrial areas.

Vertical distribution of fluorine in farmland soil profiles around phosphorous chemical industry factories.

High concentration of fluorine (F) in agricultural soils has got significant attention considering its impacts on human health, but little information was available about F distribution in farmland soil profiles around phosphorous chemical industry factories. In present study, farmland soil profiles and relevant medium samples were collected from farmlands around a main phosphorous chemical base in southwest China. At 0-100-cm profiles, concentrations of soil total F (Ft, 400.9-1612.0 mg kg-1) and water soluble F (Fw, 3.4-26.0 mg kg-1) decreased with profile depth in industrial areas. Industrial activities enhanced F concentration in soil mainly at 0-40-cm profiles. No disparity for both Ft and Fw distributions in paddy-dry land rotation field and dry land indicates short-term land utilization could not affect the F distribution in soil profiles. Correlation analysis showed soil organic matter and wind direction were important factors influencing the distribution of F in soil profiles. The shutdown of factory and government control of industrial emissions effectively decreased the ambient air F (Fa) concentrations in industrial areas. In where Fa and dustfall F concentrations were high, high soil Ft, Fw, and crop edible part F concentrations were found.

Characterization of UDP-Glycosyltransferase Involved in Biosynthesis of Ginsenosides Rg1 and Rb1 and Identification of Critical Conserved Amino Acid Residues for Its Function.

Ginsenosides attract great attention for their bioactivities. However, their contents are low, and many UDP-glycosyltransferases (UGTs) that play crucial roles in the ginsenoside biosynthesis pathways have not been identified, which hinders the biosynthesis of ginsenosides. In this study, we reported that one UDP-glycosyltransferase, UGTPg71A29, from Panax ginseng could glycosylate C20-OH of Rh1 and transfer a glucose moiety to Rd, producing ginsenosides Rg1 and Rb1, respectively. Ectopic expression of UGTPg71A29 in Saccharomyces cerevisiae stably generated Rg1 and Rb1 under its corresponding substrate. Overexpression of UGTPg71A29 in transgenic cells of P. ginseng could significantly enhance the accumulation of Rg1 and Rb1, with their contents of 3.2- and 3.5-fold higher than those in the control, respectively. Homology modeling, molecular dynamics, and mutational analysis revealed the key catalytic site, Gln283, which provided insights into the catalytic mechanism of UGTPg71A29. These results not only provide an efficient enzymatic tool for the synthesis of glycosides but also help achieve large-scale industrial production of glycosides.

Advances in ginsenoside biosynthesis and metabolic regulation.

In this paper, we reviewed the advances in ginsenoside biosynthesis and metabolic regulation. To begin with, the application of elicitors in the ginsenoside biosynthesis was discussed. Methyl jasmonate (MJ) and analogues have the best effect on accumulation of ginsenoside compared with other elicitors, and few biotic elicitors are applied in Panax genus plants tissue culture. In addition, so far, more than 40 genes encoding ginsenoside biosynthesis related enzymes have been cloned and identified from Panax genus, such as UDP-glycosyltransferases (UGT) genes UDPG, UGTAE2, UGT94Q2, UGTPg100, and UGTPg1. However, the downstream pathway of the ginsenoside biosynthesis is still not clear. Moreover, some methods have been used to increase the expression of functional genes and ginsenoside content in the ginsenoside synthesis pathway, including elicitors, overexpression, RNAi, and transcription factors. The ginsenoside biosynthesis pathway should be revealed so that ginsenoside contents can be regulated.

[Application of plant tissue culture in field of Chinese medicine resources].

Plant tissue culture technology has been widely used in the field of traditional Chinese medicine(TCM) resources with its unique advantages, playing an important role in the protection of TCM resources. In this review, some applications of plant tissue culture were summarized, including production of active compounds by using plant tissue culture, genetic diversity analysis, Dao-di herbs, elicitor application, biosynthesis and transgenic plants. Through the above researches will promote the further development of plant tissue culture technology, making it play a greater role in the field of TCM resources.

Clone and functional analysis of Seryl-tRNA synthetase and Tyrosyl-tRNA synthetase from silkworm, Bombyx mori.

Aminoacyl-tRNA synthetases are the key enzymes for protein synthesis. Glycine, alanine, serine and tyrosine are the major amino acids composing fibroin of silkworm. Among them, the genes of alanyl-tRNA synthetase (AlaRS) and glycyl-tRNA synthetase (GlyRS) have been cloned. In this study, the seryl-tRNA synthetase (SerRS) and tyrosyl-tRNA synthetase (TyrRS) genes from silkworm were cloned. Their full length are 1709 bp and 1868 bp and contain open reading frame (ORF) of 1485 bp and 1575 bp, respectively. RT-PCR examination showed that the transcription levels of SerRS, TyrRS, AlaRS and GlyRS are significantly higher in silk gland than in other tissues. In addition, their transcription levels are much higher in middle and posterior silk gland than in anterior silk gland. Moreover, treatment of silkworms with phoxim, an inhibitor of silk protein synthesis, but not TiO2 NP, an enhancer of silk protein synthesis, significantly reduced the transcription levels of aaRS and content of free amino acids in posterior silk gland, therefore affecting silk protein synthesis, which may be the mechanism of phoxim-silking disorders. Furthermore, low concentration of TiO2 NPs showed no effect on the transcription of aaRS and content of free amino acids, suggesting that TiO2 NPs promotes silk protein synthesis possibly by increasing the activity of fibroin synthase in silkworm.

Jasmonic acid and methyl dihydrojasmonate enhance saponin biosynthesis as well as expression of functional genes in adventitious roots of Panax notoginseng F.H. Chen.

Panax notoginseng, an important herbal medicine, has wide uses for its bioactive compounds and health function. In this work, we compared the content of saponin in cultivation and adventitious root. The total content of saponins in adventitious root (8.48 mg⋅g-1 ) was found lower than in the native one (3-year-old) (34.34 mg⋅g-1 ). To enhance the content of bioactive compounds, we applied elicitors jasmonic acid (JA) and methyl dihydrojasmonate (MDJ) to the adventitious root culture. It was observed that the highest total content of saponins (71.94 mg⋅g-1 ) was achieved after treatment with 5 mg⋅L-1 JA, which was 2.09-fold higher than native roots and 8.45-fold higher than the control group. The findings from high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry analysis showed that six new compounds were present after the treatment with the elicitors. Furthermore, we found that JA and MDJ significantly upregulated the expression of the geranyl diphosphate synthase, farnesyl diphosphate synthase, squalene synthase, squalene epoxidase, dammarenediol synthase, and CYP716A47 and CYP716A53v2 (CYP450 enzyme) genes; downregulated the expression of the cycloartenol synthase gene; and increased superoxide dismutase and peroxidase activities.