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Citrus Huanglongbing (HLB) is one of the most destructive diseases in the citrus industry. At present, Candidatus Liberibacter asiaticus (CLas) cannot be cultured in vitro, and there is a lack of rapid methods to test antibacterial activity, which greatly hinders the discovery of new antibacterial agents against HLB. To establish a rapid screening method for antibacterial agents against HLB with simple operation, a short cycle, and a large number of tests, the CLas contents in leaves from different citrus branches, different leaves from the same citrus branch, and two halves of the same citrus leaf were detected. Compared with the leaves on different branches and different leaves on the same branch, the difference in CLas content of the left and right halves of the same leaf was small; the difference was basically between 0.7 and 1.3. A rapid and efficient method for primary screening agents against HLB termed the "half-leaf method" was established through our long-term optimization and improvement. To verify the stability and reliability of the activity data measured using this method, 6-chloropurine riboside, which is highly soluble in water, was used as the test agent, and its antibacterial activity against HLB was tested 45 times. The results of the antibacterial activity test showed little difference in the mean values of each data group, indicating that this method could be used as a rapid method for screening agents against HLB. We used this method to test the antibacterial activity of compounds synthesized by our research group against HLB and found that some of the compounds showed good activity. [ABSTRACT FROM AUTHOR]

Citrus Huanglongbing (HLB) is one of the most destructive diseases in the citrus industry. At present, Candidatus Liberibacter asiaticus (CLas) cannot be cultured in vitro, and there is a lack of rapid methods to test antibacterial activity, which greatly hinders the discovery of new antibacterial agents against HLB. To establish a rapid screening method for antibacterial agents against HLB with simple operation, a short cycle, and a large number of tests, the CLas contents in leaves from different citrus branches, different leaves from the same citrus branch, and two halves of the same citrus leaf were detected. Compared with the leaves on different branches and different leaves on the same branch, the difference in CLas content of the left and right halves of the same leaf was small; the difference was basically between 0.7 and 1.3. A rapid and efficient method for primary screening agents against HLB termed the “half-leaf method” was established through our long-term optimization and improvement. To verify the stability and reliability of the activity data measured using this method, 6-chloropurine riboside, which is highly soluble in water, was used as the test agent, and its antibacterial activity against HLB was tested 45 times. The results of the antibacterial activity test showed little difference in the mean values of each data group, indicating that this method could be used as a rapid method for screening agents against HLB. We used this method to test the antibacterial activity of compounds synthesized by our research group against HLB and found that some of the compounds showed good activity.

ABSTRACT: Background: The emergence of SARS-CoV-2 variants of concern (VOCs) for increased transmissibility and being potentially capable of immune-escape mandates for epidemiological surveillance. Genomic alterations present in VOCs can affect the results of RT-qPCR assays for routine diagnostic purposes, leading to peculiar profiles that can be used for rapid screening of variants. This study reports a peculiar profile observed with the Allplex™ SARS-CoV-2/FluA/FluB/RSV assay and VOC-Alpha (202012/01, lineage B.1.1.7, also named VOC-UK), which was the first identified SARS-CoV-2 VOC. Methods: Samples were analyzed by two RT-qPCR assays: the Allplex™ SARS-CoV-2/FluA/FluB/RSV assay (ASFR, Seegene Technologies Inc; Seoul, South Korea) and the TaqPath COVID-19 RT-PCR (Thermo Fisher Scientific, USA). Definition of the SARS-CoV-2 variant was carried out by Sanger sequencing of the relevant S-gene regions and, in some cases, by whole genome sequencing (WGS) using the ARTIC-nCoV workflow on a MiniION (Oxford Nanopore Technologies, Oxford, UK) or a Illumina MiSeq platform (San Diego, California, USA). Results: Of the 173 SARS-CoV-2-positive specimens, all those of lineage B.1.1.7 (N=71) showed an average Cq difference between the N and S genes of +11±2 (range, +8/+15). None of the other specimens, including several different lineages (Wild-type for the analyzed regions, N=22; Gamma, N=63; Delta, N=9; B.1.258Δ, N=3; B.1.160, N=3; B.1.177.7, N=1; B.1.1.420, N=1), exhibited a similar difference in Cq values. Conclusions: The peculiar pattern of delayed N gene positivity could constitute a convenient method for VOC-Alpha screening, simultaneous to viral detection, when using the Allplex™ SARS-CoV-2/FluA/FluB/RSV assay.

[Objectives] This study was conducted to establish a qualitative method for rapid detection of pesticide residues in feed. [Methods ] A rapid screening method for 82 pesticide residues in feed was established using ultra liquid chromatography coupled with quadrupole-time of flight mass spectrometry (UPLC-Q-TOFMS) combined with optimized pretreatment methods. [Results] Feed samples were extracted with 0. 2% formic acid-acetonitrile solution, shaken, centrifuged, and re-centrifuged, and the supernatant was filtered with a 0.22 μm filter membrane for determination. The samples were separated on a Waters ACQUITY UPLC HSS T3 chromatographic column (2.1 mm x 50 mm, 1. 8 μm), and subjected to gradient elution with methanol-water solution as the mobile phase, and scanning was performed in ESI + mode. 82 compounds could be accurately qualitatively detected in 13 min. [Conclusion] This method is simple to operate, time-saving, and can be applied to rapid screening of large-scale feed. This study provides a theoretical basis for the development of new methods in the future. [ABSTRACT FROM AUTHOR]

Aflatoxins and sterigmatocystin (STC) are carcinogenic mycotoxins frequently detected in many kinds of agricultural products. An analytical method for the simultaneous detection of these mycotoxins was developed using immunoaffinity chromatography clean-up and LC–MS/MS techniques to assess the health risks associated with the exposure to aflatoxins and STC present in staple Japanese food items. A survey targeting Japanese staple food items, including rice and wheat, was conducted after validating the analytical method by conducting a single-laboratory test. A total of 550 samples were analyzed. Aflatoxins were not detected in all samples, whereas STC was detected in 22.4% of the tested samples. The dietary exposure to STC was estimated based on the results of the survey, and the amount of food intake ranged from 0.11 to 0.67 ng/kg body weight/day. The results obtained following the margin of exposure (MOE) approach revealed that STC in staple food items posed little risk to the general Japanese population. In addition, an ELISA technique for detecting STC in brown rice and wheat samples was developed, as high levels of contamination were observed in these food items. The performance of the developed ELISA technique was evaluated using STC-spiked samples, and the average recoveries were in the ranges of 94.6–121.2% for brown rice and 91.5–117.9% for wheat. The developed two analytical methods based on LC-MS/MS and ELISA techniques were efficiently utilized for assessing the health risks associated with exposure to these carcinogenic mycotoxins. • An analytical method for determination of aflatoxins and sterigmatocystin was developed. • Sterigmatocystin was mainly detected in rice and wheat products retailed in Japan. • The dietary exposure to sterigmatocystin was estimated based on the results of the survey. • The margin of exposure approach was performed for risk assessment of sterigmatocystin. • An ELISA technique for detecting sterigmatocystin in brown rice and wheat was developed. [ABSTRACT FROM AUTHOR]

• Rapid detection of SARS-CoV-2 variants of concern (VOCs) might be of epidemiological importance • Cq difference between N and S genes was found only with VOC-Alpha using the ASFR assay • This peculiar positivity profile could be a useful proxy for tracking VOC-Alpha The emergence of SARS-CoV-2 variants of concern (VOCs) for increased transmissibility and being potentially capable of immune-escape mandates for epidemiological surveillance. Genomic alterations present in VOCs can affect the results of RT-qPCR assays for routine diagnostic purposes, leading to peculiar profiles that can be used for rapid screening of variants. This study reports a peculiar profile observed with the Allplex™ SARS-CoV-2/FluA/FluB/RSV assay and VOC-Alpha (202012/01, lineage B.1.1.7, also named VOC-UK), which was the first identified SARS-CoV-2 VOC. Samples were analyzed by two RT-qPCR assays: the Allplex™ SARS-CoV-2/FluA/FluB/RSV assay (ASFR, Seegene Technologies Inc; Seoul, South Korea) and the TaqPath COVID-19 RT-PCR (Thermo Fisher Scientific, USA). Definition of the SARS-CoV-2 variant was carried out by Sanger sequencing of the relevant S-gene regions and, in some cases, by whole genome sequencing (WGS) using the ARTIC-nCoV workflow on a MiniION (Oxford Nanopore Technologies, Oxford, UK) or a Illumina MiSeq platform (San Diego, California, USA). Of the 173 SARS-CoV-2-positive specimens, all those of lineage B.1.1.7 (N=71) showed an average Cq difference between the N and S genes of +11±2 (range, +8/+15). None of the other specimens, including several different lineages (Wild-type for the analyzed regions, N=22; Gamma, N=63; Delta, N=9; B.1.258Δ, N=3; B.1.160, N=3; B.1.177.7, N=1; B.1.1.420, N=1), exhibited a similar difference in Cq values. The peculiar pattern of delayed N gene positivity could constitute a convenient method for VOC-Alpha screening, simultaneous to viral detection, when using the Allplex™ SARS-CoV-2/FluA/FluB/RSV assay. [ABSTRACT FROM AUTHOR]

γ-Polyglutamic acid (γ-PGA) is a biosynthetic outcome of glutamic acid polymerization by microbes. In the current study, we have isolated Bacillus methylotrophicus on solid differential media containing methylene blue. This is the first report mentioning the use of methylene blue to distinguish the monomeric and polymeric form of glutamic acid in the liquid medium using UV-Vis spectrophotometer. Our method can simplify the analytical process of γ-PGA confirmation using the aforementioned studies. This screening protocol is sensitive to the detection of γ-PGA quantities as low as 3 μg/mL; thus, the potent producers can be effectively screened. Furthermore, we have carried out process optimization of the present strain for γ-PGA production wherein we could obtain 1.4-fold improvement in the yield with respect to utilization of carbon source and 2.6-fold increase with respect to nitrogen source under submerged fermentation at a shake flask level. We have shown an increase in γ-PGA titer from 1.5 to 36 g/L using mannitol, monosodium glutamate, peptone, and tween 20. [ABSTRACT FROM AUTHOR]

The purpose of this study was to develop a practical radioanalytical method suitable for screening for beta- and alpha-emitting radioactive contamination in a large number and wide variety of foods in the event of a nuclear or radiological emergency. Simple and rapid solid-phase extraction was used to overcome matrix and radiometric interferences that occurred during food analysis. Benefiting from discriminative liquid scintillation counting, simultaneous detection of alpha and beta radioactivity was achieved with negligible quench effects and ~95 % counting efficiencies. Method limits of detection were ~0.06 Bq/kg for alpha and ~0.4 Bq/kg for beta radioactivity and the results were within ±20 % of the known values. [ABSTRACT FROM AUTHOR]

Ambient mass spectrometry (AMS) was applied for the first time to differentiate fresh and frozen/thawed Dicentrarchus labrax (European sea bass). One hundred and twenty samples were submitted to two extraction procedures and analyzed in positive and negative ion modes by direct analysis in real time-high resolution mass spectrometry (DART-HRMS). The four DART-HRMS datasets were concatenated with a low-level data fusion approach, and the resultant unique block of data was submitted to multivariate statistical analysis to tease out the most informative m/z values capable of codifying fresh and defrosted D. labrax. The statistical significance (p-value) and fold change (FC) of these informative signals were then evaluated with univariate analyses and tentatively assigned. The 25 features were then used to build a support vector machine (SVM) model capable of classifying D. labrax samples according to whether they were fresh or previously frozen. The SVM model has accuracy, sensitivity and specificity of 100%, both in training and test set. The SVM model was used to successfully classify an independent set of twenty fresh and frozen/thawed Salmo salar (Atlantic salmon). The concentrations of the most significant molecular features were quantified by gas-chromatography-mass spectrometry. • (+/−)DART-HRMS of polar and non-polar extracts of sea bass was performed. • The four DART-HRMS datasets were concatenated by low-level data fusion. • PLS-DA was performed on the training set to extrapolate the informative signals. • SVM classification model was constructed with the selected signals. • The built-in SVM model was validated with on hold-out subset with high accuracy. [ABSTRACT FROM AUTHOR]

The format of an existing flow-through enzyme immunoassay has been optimised for the detection of fumonisin B1 (FB1) and B2 (FB2) in maize. The visual detection limit i.e. the smallest mycotoxin concentration resulting in no colour development, is 1000μg/kg. Assay validation was performed using samples spiked with respectively only FB1 and a FB1 + FB2 mixture (ratio 1:1). Results showed that within-day and between-day coefficients of variation ranged from respectively 0.4–10.2% and 1.1–9.0%. Naturally contaminated samples were screened with the developed flow-through method and results were compared with fumonisin contamination values obtained by a validated HPLC method. The assay was demonstrated to be accurate and reliable giving no false compliant and only a low percentage of false non-compliant results. The described method offers a simple, rapid and cost-effective screening tool, thus contributing to a better consumers’ health protection. [Copyright &y& Elsevier]