Crater-Spectrum Feature Fusion Method for Panax notoginseng Cadmium Detection Using Laser-Induced Breakdown Spectroscopy.

Panax notoginseng (P. notoginseng) is a valuable herbal medicine, as well as a dietary food supplement known for its satisfactory clinical efficacy in alleviating blood stasis, reducing swelling, and relieving pain. However, the ability of P. notoginseng to absorb and accumulate cadmium (Cd) poses a significant environmental pollution risk and potential health hazards to humans. In this study, we employed laser-induced breakdown spectroscopy (LIBS) for the rapid detection of Cd. It is important to note that signal uncertainty can impact the quantification performance of LIBS. Hence, we proposed the crater-spectrum feature fusion method, which comprises ablation crater morphology compensation and characteristic peak ratio correction (CPRC), to explore the feasibility of signal uncertainty reduction. The crater morphology compensation method, namely, adding variables using multiple linear regression (MLR) analysis, decreased the root-mean-square error of the prediction set (RMSEP) from 7.0233 µg/g to 5.4043 µg/g. The prediction results were achieved after CPRC pretreatment using the calibration curve model with an RMSEP of 3.4980 µg/g, a limit of detection of 1.92 µg/g, and a limit of quantification of 6.41 µg/g. The crater-spectrum feature fusion method reached the lowest RMSEP of 2.8556 µg/g, based on a least-squares support vector machine (LSSVM) model. The preliminary results suggest the effectiveness of the crater-spectrum feature fusion method for detecting Cd. Furthermore, this method has the potential to be extended to detect other toxic metals in addition to Cd, which significantly contributes to ensuring the quality and safety of agricultural production.

Multiomics strategies for decoding seed dormancy breakdown in Paris polyphylla.

BACKGROUND: The disruption of seed dormancy is a complicated process and is controlled by various factors. Among these factors, membrane lipids and plant hormones are two of the most important ones. Paris polyphylla is an important Chinese herbaceous species, and the dormancy trait of its seed limits the cultivation of this herb. RESULTS: In this study, we investigate the global metabolic and transcriptomic profiles of Paris polyphylla during seed dormancy breaking. Widely targeted metabolomics revealed that lysophospholipids (lysoPLs) increased during P. polyphylla seed dormancy breaking. The expression of phospholipase A2 (PLA2), genes correlated to the production of lysoPLs, up-regulated significantly during this process. Abscisic acid (ABA) decreased dramatically during seed dormancy breaking of P. polyphylla. Changes of different GAs varied during P. polyphylla seeds dormancy breaking, 13-OH GAs, such as GA53 were not detected, and GA3 decreased significantly, whereas 13-H GAs, such as GA15, GA24 and GA4 increased. The expression of CYP707As was not synchronous with the change of ABA content, and the expression of most UGTs, GA20ox and GA3ox up-regulated during seed dormancy breaking. CONCLUSIONS: These results suggest that PLA2 mediated production of lysoPLs may correlate to the seed dormancy breaking of P. polyphylla. The conversion of ABA to ABA-GE catalysed by UGTs may be the main cause of ABA degradation. Through inhibition the expression of genes related to the synthesis of 13-OH GAs and up-regulation genes related to the synthesis of 13-H GAs, P. polyphylla synthesized more bioactive 13-H GA (GA4) to break its seed dormancy.

Detection of chlorpyrifos and carbendazim residues in the cabbage using visible/near-infrared spectroscopy combined with chemometrics.

Contamination of agricultural plants and food in the environment caused by pesticide residues has gained great attention of the world. Pesticide residues on vegetables constitute a potential risk to human health. A visible/near-infrared (Vis/NIR) spectroscopy combined with chemometric methods was employed to quantitatively determine chlorpyrifos and carbendazim residues in the cabbage (Brassica chinensis L.). Preprocessing methods were used for spectra denoising. Partial least squares regression (PLSR) and least squares-support vector machine (LS-SVM) were applied as the quantification models. Feature variables were selected by successive projection algorithms (SPA), random frog and regression coefficients in PLSR. As for the samples with chlorpyrifos residues, LS-SVM models based on the global spectra achieved best model performance. The best performance for carbendazim content prediction was achieved by the LS-SVM models based on the original global spectra. And modeling with SPA selected feature variables for carbendazim determination was as good as modeling with the global spectra. The results indicated that Vis/NIR spectroscopy coupled with chemometrics could be an efficient way for the assessment of the pesticide residues in vegetables, and was significant for detection of environmental pollution and ensuring food safety.

First Report of Root Rot Caused by Dactylonectria torresensis on Bletilla striata (Baiji) in Yunnan, China.

Bletilla striata (Thunb.) Rchb.f. (Orchidaceae family, known as Baiji in Chinese) is an endangered plant species with important medicinal value in China. Bletilla striata plants with symptoms of wilting, leaf yellowing and rotting on underground parts were found in Shizong (24.82822 N; 103.99084 E), Yunnan Province, China in July 2016. In the following years, this disease occurred and became prevalent when high temperature and high humidity prevailed in the fields from May to August. The incidence of the disease varied from 45 to 75%, with yield losses of 40 to 65% in different B. striata fields. To identify the causal agent of the disease, symptomatic vascular tissue fragments were soaked in 2% sodium hypochlorite for 2 min, rinsed twice with sterile distilled water, and then placed on 4% (w/v) potato dextrose agar (PDA) plates. The plates were incubated at 26°C in 12h light/dark for three days. Mycelia grown from the edges of the plant fragments were transferred to PDA plates and incubated at 26°C in 12h light/dark. After three days, hyphal tips were isolated from the edge of the colonies to PDA plates. Three hyphal-tip isolates from different plants were further studied. The colonies of these three isolates were dark red, with cottony mycelia of moderate density. Hyphae were transparent and branched. Numerous hyphae anastomosed frequently and formed hyphal coils. For further morphological analysis, sporulation was induced as described by Cabral et al. (2012) and Lombard et al. (2014). Macroconidia were abundant, 37.2 to 44.0 µm × 5.2 to 8.7 µm based on the measurement of 20 conidia from each isolate. Ascospores divided into two cells of equal size, ellipsoid to oblong-ellipsoid, 12.5 to 14.8 µm × 4.8 to 5.9 µm based on the measurement of 20 spores from each isolate. Conidiophores simple or complex, sporodochial. Simple conidiophores arising laterally or terminally from aerial mycelium, solitary to loosely aggregated, unbranched or sparsely brached, more or less cylindrical. These morphological characteristics were consistent with the description of Dactylonectria spp. by Cabral et al. (2012) and Lombard et al. (2014). From one isolate, the internal transcribed spacer (ITS) region of ribosomal DNA and the beta-tubulin (tub2) gene were amplified by polymerase chain reaction (PCR) using the primer pairs ITS1/ITS4 (White et al. 1990) and T1/Bt-2b (Cabral et al. 2012), respectively. PCR products were sequenced and deposited in GenBank with accession numbers MH458779 (ITS) and MH626485 (tub2). BLAST search revealed that both sequences showed 99 to 100% homology with the corresponding sequences of previously identified D. torresensis isolates. Specially, MH458779 shares 100% identity with the entire 463-base pair (bp) sequence of KP411806, the ITS sequence of a D. torresensis isolate identified from olive trees (Nigro et al. 2019); MH626485 shares 99% identity with the entire 320-bp sequence of KP411801, the tub2 sequence of the same olive tree isolate. In addition, the entire 609-bp sequence of MH626485 shares 99% identity with JF735478, the tub2 sequence of a D. torresensis isolate identified from grapevines (Cabral et al. 2012). To test the pathogenicity of the fungus, plants of B. striata in plastic pots filled with sterilized nursery soil were inoculated with each of the three isolates by placing a fungal-colonized wheat kernel adjacent to each health plant. Plants inoculated with noncolonized wheat kernels were used as controls. Plants in three pots (replicates), with one plant per pot, were inoculated by each isolate. The pots were maintained in a greenhouse with a 12h photoperiod at 25°C. Ten days after inoculation, black necrotic lesions identical to those observed in the field were evident on the roots of all inoculated plants. Using the same methods described above, fungi with identical morphologies as described above were isolated from lesions caused by each of the three isolates. The control plants remained healthy, and no fungus was re-isolated. This completed Koch's postulates. Based on the morphological characteristics and molecular identification, the pathogen was determined to be D. torresensis. To our knowledge, this is the first report of D. torresensis causing root rot of B. striata in Yunnan, China. It is important to further study the impacts of this new disease on B. striata production in China.

High-Sensitivity Determination of Nutrient Elements in Panax notoginseng by Laser-induced Breakdown Spectroscopy and Chemometric Methods.

High-accuracy and fast detection of nutritive elements in traditional Chinese medicine Panax notoginseng (PN) is beneficial for providing useful assessment of the healthy alimentation and pharmaceutical value of PN herbs. Laser-induced breakdown spectroscopy (LIBS) was applied for high-accuracy and fast quantitative detection of six nutritive elements in PN samples from eight producing areas. More than 20,000 LIBS spectral variables were obtained to show elemental differences in PN samples. Univariate and multivariate calibrations were used to analyze the quantitative relationship between spectral variables and elements. Multivariate calibration based on full spectra and selected variables by the least absolute shrinkage and selection operator (Lasso) weights was used to compare the prediction ability of the partial least-squares regression (PLS), least-squares support vector machines (LS-SVM), and Lasso models. More than 90 emission lines for elements in PN were found and located. Univariate analysis was negatively interfered by matrix effects. For potassium, calcium, magnesium, zinc, and boron, LS-SVM models based on the selected variables obtained the best prediction performance with Rp values of 0.9546, 0.9176, 0.9412, 0.9665, and 0.9569 and root mean squared error of prediction (RMSEP) of 0.7704 mg/g, 0.0712 mg/g, 0.1000 mg/g, 0.0012 mg/g, and 0.0008 mg/g, respectively. For iron, the Lasso model based on full spectra obtained the best result with an Rp value of 0.9348 and RMSEP of 0.0726 mg/g. The results indicated that the LIBS technique coupled with proper multivariate chemometrics could be an accurate and fast method in the determination of PN nutritive elements for traditional Chinese medicine management and pharmaceutical analysis.

Proteomic analysis of the rice (Oryza officinalis) provides clues on molecular tagging of proteins for brown planthopper resistance.

BACKGROUND: Among various pests, the brown planthopper (BPH) that damages rice is the major destructive pests. Understanding resistance mechanisms is a critical step toward effective control of BPH. This study investigates the proteomics of BPH interactions with three rice cultivars: the first resistant (PR) to BPH, the second susceptible (PS), and the third hybrid (HR) between the two, in order to understand mechanisms of BPH resistance in rice. RESULTS: Over 4900 proteins were identified from these three rice cultivars using iTRAQ proteomics study. A total of 414, 425 and 470 differentially expressed proteins (DEPs) were detected from PR, PS and HR, respectively, after BPH infestation. Identified DEPs are mainly enriched in categories related with biosynthesis of secondary metabolites, carbon metabolism, and glyoxylate and dicarboxylate metabolism. A two-component response regulator protein (ORR22) may participate in the early signal transduction after BPH infestation. In the case of the resistant rice cultivar (PR), 6 DEPs, i.e. two lipoxygenases (LOXs), a lipase, two dirigent proteins (DIRs) and an Ent-cassa-12,15-diene synthase (OsDTC1) are related to inheritable BPH resistance. A heat shock protein (HSP20) may take part in the physiological response to BPH infestation, making it a potential target for marker-assisted selection (MAS) of rice. Quantitative real-time polymerase chain reaction (qRT-PCR) revealed eight genes encoding various metabolic proteins involved in BPH resistance. During grain development the expressions of these genes varied at the transcriptional and translational levels. CONCLUSIONS: This study provides comprehensive details of key proteins under compatible and incompatible interactions during BPH infestation, which will be useful for further investigation of the molecular basis of rice resistance to BPH and for breeding BPH-resistant rice cultivars.

Experimental study and performance analysis of solar-driven exhaust air thermoelectric heat pump recovery system.

Exhaust air heat recovery is of great significance for building energy conservation. Since passive heat recovery systems use temperature or enthalpy difference between outdoor air and indoor air to drive the system, the temperature of fresh air supply cannot meet indoor requirements and the exhaust heat is not fully recovered. In this study, a solar-driven exhaust air thermoelectric heat pump recovery (SDEATHP) system is tested and evaluated for its ability to recover thermal energy from exhaust air to cool or heat fresh air. An experimental platform was established to test its performance. Results show that the SDEATHP system can obtain higher fresh air supply temperature in winter and lower fresh air supply temperature in summer. The system requires only 3.12 W of power for the fans, and the average relative cooling coefficient in summer and the average relative heating coefficient can reach 50.6 and 57.9, respectively. The optimal operating current and voltage of TE modules and photovoltaic system is analyzed, and then the number and types of electrical connections for the TE modules in SDEATHP system are discussed. The SDEATHP system provides a new method for building energy recovery and fresh air supply.

The spatial and temporal variation of total suspended solid concentration in Pearl River Estuary during 1987-2015 based on remote sensing.

The movement and migration of total suspended solid (TSS) are the essential component of global material cycling and change. Based on the TSS concentrations retrieved from 112 scenes of Landsat remote sensing imageries during 1987-2015, the spatial and temporal variations of TSS concentration in high flow season and low flow seasons of six sub-regions (west shoal, west channel, middle shoal, east channel, east shoal and Pearl River Estuary Chinese White Dolphin National Nature Reserve and its adjacent waters (NNR)) of Pearl River Estuary (PRE) were analyzed and compared by statistical simulation. It was found that TSS concentrations in east and west shoals were about 23mg/L and 64mg/L higher than that of the middle shoal, respectively. There was a significant decreasing trend of TSS concentration from the northwest (223.7mg/L) to southeast (51.4mg/L) of study area, with an average reduction of 5.86mg/Lperkm, which mainly attributes to unique interaction of runoff and tide in PRE. In high flow season, there existed a significant and definite annual cycle period (5-8years) of TSS concentration change primarily responding to the periodic variation of precipitation. There were five full-fledged period changes of TSS detected in west shoal and west channel (the years of changes in 1988, 1994, 1998, 2003, 2010, 2015), while there were the last four cycle periods found in middle shoal, east channel, east shoal and NNR only. TSS concentrations in shoals and channels of PRE showed a significant decreased trend mainly due to the dam construction at the same time, with an average annual TSS concentration decrease of 5.7-10.1mg/L in high flow season from 1988 to 2015. There was no significant change trend of TSS concentration in NNR before 2003, but the TSS concentration decreased significantly after the establishment of the NNR since June 2003, with an average annual decrease of 9.7mg/L from 2004 to 2015. It was deduced that man-made protection measures had a great influence on the variation trend and intensity of TSS concentration in PRE, but had little effect on the cycle of TSS changes, indicating that the cyclical change is a very strong natural law. In low flow season, there was no significant change trend of TSS concentrations in PRE except that TSS concentrations in west channel and middle shoal showed a weak increasing trend (2.1mg/L and 2.9mg/L, respectively), which is probably because of controlled discharge for avoiding the intrusion of saltwater in PRE. Evidently, the change trend and cycle periods of TSS concentration in high- and low-flow seasons in six sub-regions of PRE had significant difference. The decreasing trend and cycle periods of TSS concentration mainly occurred in high flow season. The change trend and cycle periods of TSS concentration in low flow season was relatively small in PRE. The study shows that long series mapping of Landsat remote sensing images is an effective way to help understanding the spatial and temporal variation of TSS concentrations of estuaries and coasts, and to increase awareness of environmental change and human activity effects.

Enhanced gene replacement frequency in KU70 disruption strain of Stagonospora nodorum.

To improve the efficiency of gene disruption in Stagonospora nodorum, the putative KU70 gene encoding the Ku70 protein involved in the nonhomologous end-joining double DNA break repair pathway was identified and deleted. The KU70 disruption strain showed no apparent defect in vegetable growth, conidiation and pathogenicity on wheat and barley compared with the wild-type strain. The effect of the absence of KU70 on gene replacement frequency was tested by disruption of TOXA encoding toxin A and LIP2 encoding a putative lipase. Frequency of gene replacement for both genes was dramatically increased in the KU70 disruption strain, compared with the low frequency in the wild-type recipient.

[Battery and power management of portable telemonitoring system].

Biomedical Engineering of Electronic Engineering Deparment, Fudan University Shanghai, 200433 Based on the pulse-coded transmitting and wide-band receiving system, this paper describes a research of phase design a special power management circuit according to the particular demands of a real-time and continuously monitor system is essential. Combined with the requirement of voltage and current in separated module, three aspect must be considered, that is, how to select the functional component, how to accomplish voltage converting and how to carry on battery management. The test at last shows that, using this circuit and the 4400 mAh battery the energy utilization is more than 88%, and the work time is more than 20 hours.

[Design of a flyback switch mode power supply for multichannel electrophysiological stimulators].

In order to supply the multichannel electrical stimulator, a DC-DC flyback switch mode power supply based on a high-performance current mode controller UC3845 has been designed. The experimental results indicate that the power supply has satisfied the demands and can supply the multichannel electrical stimulator and similar apparatuses.