Research on the Application of Molecular Image Processing in Rice Quality Inspection.

Objective: With the improvement of living standards, consumers are paying more and more attention to the quality of rice. Traditional rice quality detection relies on human sensory judgment, which is inaccurate and inefficient. With the continuous development of molecular imaging technology, more and more scholars at home and abroad have begun to pay attention to its application in the nondestructive testing of agricultural products. Molecular imaging technology combines the advantages of spectral technology and image technology, which can achieve rapid, nondestructive and accurate detection of rice quality. In this paper, taking rice as the research object, we carried out nondestructive detection research on rice varieties, moisture and starch content using molecular imaging technology. We proposed a rapid detection method based on molecular imaging technology for rice variety identification, moisture content and starch content. Molecular images of the rice samples from four origins were obtained using a molecular imaging system, the regions of interest of the rice were identified and, spectral data, textural features and morphological features of the rice were extracted. Spectral, textural and morphological features were selected by principal component analysis (PCA), and nine feature wavelengths were obtained and an optimal model was established with an accuracy of 91.67%, which demonstrated the feasibility of molecular imaging. By comparing the models, the BCC-LS-SVR model based on the RB function had the highest accuracy with R2 of 0.989, RMSEP of 0.767%, R2 of 0.985, and RMSEC of 0.591%. Moreover, starchy rice was detected using molecular imaging. The PCA-SVR model based on the RBF kernel function had the highest accuracy with R2 of 0.989, RMSEC of 0.445%, R2 of 0.991, and RMSEP of 0.669%. Our models demonstrated high accuracy in identifying rice varieties, as well as quantifying moisture and starch content, showcasing the feasibility of molecular imaging technology in rice quality assessment. This research offers a rapid, nondestructive, and accurate method for rice quality assessment, promising significant benefits for agricultural producers and consumers.

Pesticide residue and dietary intake risk of vegetables grown in Shanghai under modern urban agriculture in 2018-2021.

Shanghai as an international metropolis is representative of modern urban agriculture in China, so it is of great significance to analyse the pesticide residue in vegetables grown in Shanghai. This study investigated the residue of 68 commonly used pesticides (divided into insecticides, fungicides, herbicides and plant growth regulators) in 7028 vegetable samples in Shanghai from 2018 to 2021, and estimated the dietary intake risk of these pesticides. These samples were divided into 6 categories. A total of 29.21% of vegetable samples had pesticide residues, and 0.47% of samples exceeded the maximum residue limits (MRLs) set by the national food safety standard of China. Leafy vegetables had the highest detection rate of pesticide residues (32.9%), multiple detection rate (12.2%), pesticide residue concentration (35.7 mg/kg), and the number of samples exceeding the MRL (30). There were 36 out of 68 pesticides detected in vegetables, and the top 3 were dimethomorph, propamocarb and acetamiprid. The target hazard quotient (THQ) and hazard index (HI) of these noticeablepesticides were all less than 1, illustrating that there may be no obvious health hazard for residents exposed to the pesticide levels. This study can promote the green development of the pesticide industry and provide important reference data for the monitoring of pesticide residues and their hazards under modern urban agriculture.

Heavy metal contamination in Shanghai agricultural soil.

As heavy metals in soil could enrich in biomass and pose health risk to human, it is vital to monitor their contaminations to ensure qualified agricultural production. In this study, we collected >4000 soil samples from agricultural fields in Shanghai during 2010∼2020, and unveiled heavy metal contamination status in this metropolitan. We found that although Shanghai has a long industrialization history, the heavy metal levels in agricultural soil are within safe ranges according to national standard. Specifically, the median levels of Cd, Hg, As, Pb, Cr and Cu are 0.11, 0.13, 7.47, 23.80, 41.00 and 28.30 mg/kg, respectively, which are as good as, or even better than national averages. However, there are spatial and temporal heterogeneities for heavy metal contaminations in Shanghai. For example, the levels of Cd, Hg and Cr are relatively higher in some districts with high industry density, which should be further monitored in the future. Moreover, while the levels for Cd, Cr and Pb have decreased, the level for Hg has mildly increased during this period which needs counteractive measures. Correlation analysis of heavy metal levels and soil fertility parameters suggested overuse of fertilizers may be related to heavy metal contamination in some regions. In summary, our study present by far the largest and most comprehensive landscape of heavy metal contamination in Shanghai agricultural soil, which will be useful for future policy-design and land use planning to ensure safe agricultural production.

Characteristics of arsenic speciation in mainly cultured shellfish from Sanmen Bay, Zhejiang Province, China.

Sanmen Bay plays a crucial role in economic shellfish aquaculture in China, yet few studies exist on the arsenic speciation of shellfish from this area. In this study, arsenic speciation of 11 cultured shellfish species from Sanmen Bay were analyzed by HPLC/ICP-MS. The results showed that organic arsenic particularly AsB, was the dominant arsenic species, constituting 21 %-71 % of the total arsenic. Conversely, the levels of inorganic arsenic were relatively low, ranging from 0.007 to 0.093 mg/kg, only accounted for 0.2 %-5.7 % of the total arsenic. There was no significant level correlation between inorganic arsenic and total arsenic in Sanmen Bay shellfish, so the concentration of inorganic arsenic did not increase with the total arsenic. Overall, the present study firstly revealed the arsenic speciation of shellfish from Sanmen Bay and also suggested that the proportion of inorganic arsenic should be considered in the revision of arsenic limit values.

Microbiota Profiles of Hen Eggs from the Different Seasons and Different Sectors of Shanghai, China.

Hen eggs are one of the most popular foods worldwide, and their safety is critical. Employing 16S rRNA full-length sequencing is an effective way to identify microorganisms on or in eggs. Here, hen eggs collected from poultry farms over four seasons, as well as from markets in Shanghai, were analyzed with third-generation sequencing. Firmicutes (44.46%) and Proteobacteria (35.78%) were the two dominant phyla, and Staphylococcus, Acinetobacter, Aerococcus, Psychrobacter, and Lactobacillus were the dominant genera. The dominant genera on the eggshell surfaces from the farms varied with the seasons, and the highest contamination of Staphylococcus (32.93%) was seen in the eggs collected during the summer. For the market samples, Pseudomonas was the most abundant in content, with Staphylococcus being the most-often genera found on the eggshell surfaces. Moreover, several potential pathogenic bacteria including Riemerella anatipestifer (species), Klebsiella (genus), and Escherichia/shigella (genus) were detected in the samples. The results revealed the impacts of weather on the microbiota deposited on an eggshell's surface, as well as the impacts due to the differences between the contents and the surface. The results can help disinfect eggs and guide antibiotic selection.

Two electrochemiluminescence immunosensors for the sensitive and quantitative detection of the CP4-EPSPS protein in genetically modified crops.

Two different models of electrochemiluminescence (ECL) immunosensors for the sensitive and quantitative detection of the CP4-EPSPS protein in genetically modified (GM) crops were proposed in this study. One was a signal-reduced ECL immunosensor based on nitrogen-doped graphene, graphitic carbon nitride and polyamide-amine (GN-PAMAM-g-C3N4) composites as the electrochemically active substance. The other model was a signal-enhanced ECL immunosensor based on a GN-PAMAM modified electrode for the detection of CdSe/ZnS quantum dots (QDs)-labeled antigens. The ECL signal responses of the reduced and enhanced immunosensors linearly decreased as the increase of the soybean RRS and RRS-QDs content in the range of 0.05% to 1.5% and 0.025% to 1.0%, with the limits of detection of 0.03% and 0.01% (S/N = 3), respectively. Both of the ECL immunosensors showed good specificity, stability, accuracy, and reproducibility in the analysis of real samples. The results indicate that the two immunosensors provide an ultra-sensitive and quantitative approach for the determination of the CP4-EPSPS protein. Due to their outstanding performances, the two ECL immunosensors could be useful tools for achieving the effective regulation of GM crops.

Simultaneous and Sensitive Detection of Three Pesticides Using a Functional Poly(Sulfobetaine Methacrylate)-Coated Paper-Based Colorimetric Sensor.

Chlorpyrifos (CHL), profenofos (PRO) and cypermethrin (CYP) are widely used in combination to increase crop yields. However, these three pesticides can cause serious harm to human health and do not easily degrade. In this study, a novel visible paper sensor has been prepared successfully and different colorimetric reactions were utilized to detect the three pesticides simultaneously. The sensor was constructed by grafting a zwitterionic polymer onto a cellulose filter (CF) and placing it on a glass surface modified with PDMS. The branch shape was designed to form multiple detection areas, which were modified with specific pesticides and corresponding chromogenic reagents. The as-prepared colorimetric platform exhibited high sensitivity, a short detection time, a good linear response and a low detection limit (LOD) for the three pesticides (chlorpyrifos: y = 46.801 - 1.939x, R2 = 0.983, LOD = 0.235 mg/L; profenofos: y = 40.068 + 42.5x, R2 = 0.988, LOD = 4.891 mg/L; cypermethrin: y = 51.993 + 1.474x, R2 = 0.993, LOD = 4.053 mg/L). The comparison of the results obtained by the proposed paper sensor and those obtained by spectrophotometry further revealed the stability and reliability of the paper sensor. In particular, the color intensity of the interaction between the pesticides and coloring agents could be directly observed by the human eye. The consistency of the colorimetric/optical assay was proven in real target pesticide samples. Thus, this sensing strategy provides a portable, cost-effective, accurate and visualized paper platform, which could be suitable for application in the fruit and vegetable industry for monitoring CHL, PRO and CYP in parallel.

Detection and genetic characterization of canine kobuvirus from stray dogs in Shanghai, China.

In this study, rectal samples collected from 60 stray dogs in dog shelters were screened for canine kobuvirus and other enteroviruses by quantitative real-time reverse transcription polymerase chain reaction. Canine kobuvirus was detected in 25% (15/60) of the samples. In the 15 positive samples, the coinfection rates of canine distemper virus, canine coronavirus, canine astrovirus, canine norovirus, and canine rotavirus were 26.67%, 20.00%, 73.33%, 0%, and 20.00%, respectively. Phylogenetic analysis based on partial VP1 sequences identified a novel canine kobuvirus that was a recombinant of canine and feline kobuvirus. Bayesian evolutionary analysis revealed that the rate of evolution of the VP1 gene of canine kobuvirus was 1.36 × 10-4 substitutions per site per year (95% highest posterior density interval, 6.28 × 10-7 - 4.30 × 10-4 substitutions per site per year). Finally, the divergence time of VP1 was around 19.44 years ago (95% highest posterior density interval, 12.96-27.57 years).

A fast, sensitive, low-cost electrochemical paper-based chip for real-time simultaneous detection of cadmium (â ¡) and lead (â ¡) via aptamer.

A novel electrochemical paper-based microfluidic chip was firstly developed to simultaneously detect cadmium (Ⅱ) and lead (Ⅱ) in vegetable and fruit samples. The patterned filter paper was prepared through the printing of three-electrode patterns on filter paper using an automatic screen-printing machine. Portable and low-cost (less than $1) electrochemical paper-based chips are prepared by filling conductive ink and hot pressing. The paper-based chip could realize signal amplification through gold nanoparticles and seed solutions. Cadmium (Ⅱ) and lead (Ⅱ) were sensitively detected by their aptamers labeled with methylene blue and ferrocene, separately. Under the optimal experimental parameters, the paper-based chip detected cadmium (Ⅱ) and lead (Ⅱ) as low as 23.31 and 46.23 pmol/L (3σ) with a wide linear range from 0.1 to 1000 nmol/L and exhibited excellent selectivity. The RSD was 6.41% (cadmium (Ⅱ)) and 4.20% (lead (Ⅱ)). Compared with other methods, the paper-based chip could complete the detection within 15 min and could be stored at -20 °C for 5 days. Furthermore, the results for vegetable and fruit samples were agreed with the results of the graphite furnace atomic absorption spectrophotometer, in which the recovery rates were 93.20%-95.80%.

The maize premature senesence2 encodes for PHYTOCHROME-DEPENDENT LATE-FLOWERING and its expression modulation improves agronomic traits under abiotic stresses.

Among the various abiotic stresses, water and nitrogen are major stress factors that limit crop productivity worldwide. Since leaf nutrients remobilization during leaf senescence might impact response to abiotic stress in crops, we undertook a forward screen of the Mutator-active approach to identify premature senescence loci in maize. A mutant line isolated from a cross between a Pioneer Brand elite line and a public Mutator-active material, designated premature senescence2 (pre2), expressed leaf senescence during flower initiation. The Pre2 gene encodes PHYTOCHROME-DEPENDENT LATE-FLOWERING (PHL) protein, a nuclear receptor coactivator. The pre2-1 mutant allele was not a null mutation but produced a functional wild-type transcript along with multiple mRNA species of varying lengths resulting from the alternate splicing of the Pre2 gene. The PHL accelerates flowering by suppressing the inhibitory effect of phyB on flowering in Arabidopsis (Endo et al., 2013). The ZmPRE2 polypeptide is highly conserved in plant species and has two identifiable motifs namely SPT20 and MED15. The Spt20 domain, which is a part of the SAGA (Spt-Ada-Gcn5 acetyltransferase) complex, is involved in histone deacetylation and MED15 proteins have nuclear functions in mediating DNA Pol II transcription. The differential spliced mature transcripts in both the pre2 alleles, as a result of transposon interference, were producing truncated proteins that lacked polyglutamine (Q) tract near the C-terminus and might be causative of the premature senescence phenotype in maize. Endogenous gene suppression of ZmPre2 by RNAi improves maize agronomic performance under both water stress and suboptimal nitrogen conditions. The homozygous T-DNA knockout of the pre2 homolog in Arabidopsis (At1G72390; the same insertional allele used by Endo et al., 2013) results in higher biomass, delayed maturity, enhanced tolerance to drought, and improved nitrogen utilization efficiency. The Arabidopsis mutant also showed hypersensitive response to 1 µM ABA (abscisic acid) concentration. These results indicate that the PHL protein plays a direct or indirect role in ABA-dependent drought and N signaling pathways.

Identification of quantitative trait loci and a candidate locus for freezing tolerance in controlled and outdoor environments in the overwintering crucifer Boechera stricta.

Development of chilling and freezing tolerance is complex and can be affected by photoperiod, temperature and photosynthetic performance; however, there has been limited research on the interaction of these three factors. We evaluated 108 recombinant inbred lines of Boechera stricta, derived from a cross between lines originating from Montana and Colorado, under controlled long day (LD), short-day (SD) and in an outdoor environment (OE). We measured maximum quantum yield of photosystem II, lethal temperature for 50% survival and electrolyte leakage of leaves. Our results revealed significant variation for chilling and freezing tolerance and photosynthetic performance in different environments. Using both single- and multi-trait analyses, three main-effect quantitative trait loci (QTL) were identified. QTL on linkage group (LG)3 were SD specific, whereas QTL on LG4 were found under both LD and SD. Under all conditions, QTL on LG7 were identified, but were particularly predictive for the outdoor experiment. The co-localization of photosynthetic performance and freezing tolerance effects supports these traits being co-regulated. Finally, the major QTL on LG7 is syntenic to the Arabidopsis C-repeat binding factor locus, known regulators of chilling and freezing responses in Arabidopsis thaliana and other species.