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Background: Cases of cruelty can occur in wild animal, livestock, and pet animal. Cruelty to cats choose to be the background of this research because many cases of cruelty to cats have not reported although the cases are still high. Aim: Aim of this research was to know how much dilution of cat blood that can still be detected by Leucomalachite Green (LMG) and Takayama reagent. Methods: Three samples of domestic cat blood were diluted with ratio 1:10; 1:100; 1:1,000; 1:10,000; and 1:100,000. Bloodstain is made by dropping each blood dilution on the filter paper for LMG test and on the object glass for Takayama test. Bloodstain for LMG test was done with ten repetitions from each sample and duplo for Takayama test. Positive results from the LMG test are presented as a bluish-green discoloration in stains. A positive result from the Takayama test is the formation of hemochromogen crystals under a microscope with 400x magnification. Results: Based on this research, cat bloodstain can be detected with LMG reagent until 1:40,000 dilution, while Takayama reagent only can detect cat bloodstain until 1:1,000. Conclusion: LMG and Takayama reagent are reagents that are often used in human blood spot testing. If there is a case of violence against cats and other animals, these two reagents can be relied on to help with the proof process. [Open Vet J 2024; 14(10.000): 2609-2617]

It is a common practice in forensic casework to use presumptive tests for blood stains before DNA extraction and testing. Stains are usually swabbed and then the swabs are sent for analysis. The Kastle-Meyer (KM) and Leucomalachite green (LMG) presumptive tests for blood are widely used, and their sensitivities have been thoroughly tested in the literature in solution and directly on stains, but not on swabbed stains to mimic casework. In this study, the sensitivity of the KM and LMG tests was tested on eight blood dilutions on cotton fabric and ceramic tile that were stained and subsequently swabbed. Both tests showed sensitivity up to 1:5000, which is slightly lower than reported values in solution or directly on stain but still highly effective in most cases. Stains were also cleaned with common agents, then swabbed and re-tested. Stained ceramic tiles cleaned with soap/water or bleach gave mixed positive and negative results for the 1:10 dilution, presumably due to variance in how thoroughly each investigator cleaned the stain, and other dilutions were undetectable after cleaning. The LMG test gave false positives for bleach cleaned stains, due to reagent reactivity with bleach. Surprisingly, blood was detectible up to the 1:100 dilution with both tests on stained cotton fabric that was cleaned in a washing machine with detergent and dried. Ultimately the KM and LMG presumptive tests remain effective tools for swabbed blood stains, and their practicality for cleaned stains is dependent on material containing the stain, cleaning agent and processing. [ABSTRACT FROM AUTHOR]

We investigated fourteen antibiotics, three illegal drugs, and two toxic elements in commercially available gastropods from southeast China. The data revealed high detection frequencies (DFs) for florfenicol (61.32%), florfenicol amine (47.33%), and thiamphenicol (39.88%), with maximum concentrations of 1110, 2222, and 136 μg/kg wet weight (ww), respectively. The DFs of illegal drugs were 3.54% for leucomalachite green and 0.3% for chloramphenicol. The average levels of Cd and As were 1.17 and 6.12 mg/kg ww, respectively. All chemicals presented diverse DFs in different sampling months. The highest DFs of florfenicol, florfenicol amine, and thiamphenicol were in July. The health risk assessment showed that targeted hazard quotients (THQs) of antibiotics, Cd, and As for children, teens, and adults were all less than one. Notably, the toxic elements (Cd and As) were identified as the primary health risk in gastropods, contributing to over 90% of the total THQs. [ABSTRACT FROM AUTHOR]

Leucomalachite green (LMG), a derivative antimicrobial agent, can accumulate in animal tissues for long periods and is categorized as a carcinogen affecting consumer health. Therefore, determining the contamination of aquatic products by LMG is necessary to prevent residual contamination. In the work described herein, the detection of LMG based on a colorimetric method using gold nanoparticles (AuNPs) was developed. The specificity of isolated single-stranded DNA aptamers to LMG was proven by using LMG and other antibiotics. The binding affinity of the LMG-aptamer showed a Kd value of 1.94 pM. Furthermore, a colorimetric detection module was successfully developed, showing a limit of detection (LOD) value of LMG at 250 nM using standard LMG substance. Taken together, this research demonstrates a rapid and sensitive method to detect chemical residues, reducing the possibility of contamination in fishery products. Considering these findings, the aptamer-based colorimetric approach might be feasible to utilize as a biosensing module, providing a rapid, inexpensive analysis method for detecting deposited chemical residues. [ABSTRACT FROM AUTHOR]

A simultaneous analytical method for two prohibited fungicides and their metabolites was developed alongside a simultaneous analytical method for two hormone compounds. For the fungicides, conditions such as the SPE cartridge type, pH conditions, and additives were varied while for the hormones, the elution solvents and pH conditions were varied, and finally, the optimal conditions were selected for each compound group. Target fungicide compounds and medroxyprogesterone acetate were ionized in positive mode while diethylstilbestrol was ionized in negative mode. For the fungicides, with the injection of additives and buffer, the MCX cartridge showed more stable recoveries (85.1-140.0%) compared to the HLB (82.3-251.7%) and combined cartridges (56.1-277.2%). The accuracy and precision of the analytical method were 83.2-130.1% and 6.8-15.0%, respectively. The method detection limit and limit of quantification from this study were lower than those reported in previous studies. Meanwhile, for hormones, methanol was the most appropriate elution solvent in the presence of ascorbic acid additive and at pH 2.5. Accuracy and precision ranged from 75.3-106.6% and 4.3-9.1%, respectively. This study's optimized simultaneous analytical methods can be used to proactively detect prohibited substances in seawater and aquaculture farms. [ABSTRACT FROM AUTHOR]

We investigated fourteen antibiotics, three illegal drugs, and two toxic elements in commercially available gastropods from southeast China. The data revealed high detection frequencies (DFs) for florfenicol (61.32%), florfenicol amine (47.33%), and thiamphenicol (39.88%), with maximum concentrations of 1110, 2222, and 136 μg/kg wet weight (ww), respectively. The DFs of illegal drugs were 3.54% for leucomalachite green and 0.3% for chloramphenicol. The average levels of Cd and As were 1.17 and 6.12 mg/kg ww, respectively. All chemicals presented diverse DFs in different sampling months. The highest DFs of florfenicol, florfenicol amine, and thiamphenicol were in July. The health risk assessment showed that targeted hazard quotients (THQs) of antibiotics, Cd, and As for children, teens, and adults were all less than one. Notably, the toxic elements (Cd and As) were identified as the primary health risk in gastropods, contributing to over 90% of the total THQs.

[Display omitted] • Two fluorescence aptasensors for malachite green (Sensor 1) and leucomalachite green (Sensor 2) detection were developed. • Any modification or large-sized instruments were not required. • Targets caused conformational changes of aptamers. • A higher sensitivity was obtained. • Successful application in water and fish samples was achieved. Simple fluorescence aptasensors were established for malachite green (MG) and leucomalachite green (LMG) detection using G-quadruplex dyes thioflavin T (ThT) and thiazole orange (TO), respectively. ThT and TO, initially non-fluorescent in aqueous solution, exhibited fluorescence upon binding to target-specific aptamers, resulting in the stabilization of G-quadruplex structures. The specific binding between G-quadruplex and MG could induce conformational changes, which caused a pronounced quenching of fluorescence emitted by the intercalator, providing a possibility for detection. The developed assays demonstrated a good linear relationship in the range of 0–1000 μg L-1 for MG and 0–250 μg L-1 for LMG, with low limits of detection of 5.4 × 10-3 μg L-1 and 0.1 μg L-1 respectively. More importantly, satisfactory detection results in water and fish samples were obtained. Noteworthy was that the uncomplicated fluorescent aptasensors operated effectively without the need for any modifications. The experimental process was facile and realized in homogeneous solution, which exhibited quick responsiveness after simple mixing. [ABSTRACT FROM AUTHOR]

[Display omitted] • A hot-stamping method for fabricating Au microsensor on various flexible substrates. • An electrochemical POC sensor for direct detection of leucomalachite green. • The proposed method gives a promising solution for flexible POC sensor fabrication. Leucomalachite green (LMG) is the metabolic product of malachite green, which is a common aquaculture antimicrobial known for its high toxicity and long persistence. To date, few reports on the direct detection of LMG using electrochemical point-of-care (POC) sensors have been published. In the present work, flexible gold (Au) microsensors were fabricated from nanometer-thin Au leaves for the first time on different substrates, such as polyethylene terephthalate, thermoplastic polyurethane, silicone, polyvinyl chloride wristbands, and nitrile gloves, through simple hot stamping. The entire fabrication process did not involve toxic solvents and complex equipment, and the material cost was only $0.1 per microsensor. The morphology, electrochemical properties, and sensing performance of the microsensors were characterized by scanning electron microscopy, cyclic voltammetry, and differential pulse voltammetry. Benefiting from the excellent catalytic activity and conductivity of Au, the microsensors exhibited outstanding direct sensing capability for LMG with a detection limit of 6.3 nM. Moreover, the microsensors demonstrated excellent recovery rates in real sample analysis, validating their practicality. The technology reported in this work provides a pioneering and effective solution for the sensitive and convenient POC direct detection of LMG and further allows for the fabrication of Au microsensors on different flexible and conformal substrates, offering sensitive solutions for POC detection in environmental, food safety, and healthcare applications. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Bioprocess Engineering is the property of Chinese Journal of Bioprocess Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Blood-stain or blood splatter analysis when used properly can assist in establishing a chain of events linked to violent crimes (Bevel and Gardner, 2008). The methods used in detecting blood splatters in the field are chemical methods. Leucomalachite green is a colorimetric test which is used to test the presence of blood (Castro and Coyle, 2008). Takayama reagent is a confirmatory test for blood (Strassman, 1922). The aim of this research is to detect the blood splatter on cotton fabric after it has been dried for 1 day, 3 days and 5 days using Leucomalachite green and Takayama reagent. Cotton fabric was specifically chosen for this experiment with 3 different periods of drying. The unstained cotton fabric was cut into squares, and a blood sample was splattered on each piece. The fabrics splattered with blood were then dried for 1 day, 3 days and 5 days. The blood splatter was then tested using Leucomalachite green and Takayama reagent, and the results were noted afterwards. For the control, red food dye was dried for 1 day then tested with Leucomalachite green and Takayama reagent. The image results of the Leucomalachite green test are analyzed using ImageJ software 1.8.0_112 where the red, green and blue pixels are converted to grayscale. The image results of the Takayama test are graded based on the number and pattern of crystal. In conclusion, Leucomalachite green and Takayama reagent are able to detect cat blood splatter on the cotton fabric. Leucomalachite green produced a higher intensity/ darker colour as a result of an older sample, and the lower intensity/ lighter colour as a result of a fresher sample of the Leucomalachite green test. Takayama reagent produced a densely packed pattern of crystals as a result of an older sample, and the loosely packed pattern of crystals as a result of a fresher sample of the Takayama test.

A sensitive dual immunochromatographic test strip (dual-ICTS) was developed to detect malachite green (MG) and its metabolite, leucomalachite green (LMG), using two types of gold nanoparticles: round-shaped (red) and star-shaped (blue). The detection limits were determined to be 0.221 μg L−1 for MG and 0.214 μg L−1 for LMG, respectively. The dual-ICTS provided a cut-off value of 1.8 μg L−1 for MG and LMG detection. The dual-ICTS successfully detected MG and LMG in food samples, with recovery rates ranging from 86 % to 116 %. The dual-ICTS was evaluated by correlation analysis between the proposed assay and the well-established enzyme-linked immunosorbent assay in the MG and LMG detection. This is the first report on the development of the ICTS that can detect both MG and LMG at the same time within only 5 min, making it a sensitive and rapid tool for on-site detection. [Display omitted] • Two colored gold nanoparticles were applied as dual - color labels in ICTS. • A novel dual-ICTS was fabricated for simultaneous detection of MG and LMG. • The dual-ICTS provided a cut-off value of 1.8 μg L−1 for MG and LMG detection. • ICTS is a rapid, for on-site simultaneous detection for MG and LMG within 5 min. [ABSTRACT FROM AUTHOR]

This study explored the treatment of Leucomalachite Green (LMG) solutions using an electron beam and sodium persulfate (Na 2 S 2 O 8), employing Box-Behnken design (BBD) to optimize operational variables such as absorbed dose, initial pH and Na 2 S 2 O 8 concentration. The findings highlighted an optimal absorbed dose of 4.5 kGy, a Na 2 S 2 O 8 concentration of 1.0 mM, and an initial pH of 6, leading to a remarkable 97.77% removal of LMG. The adjusted R2 for the model indicated a close match of 1.4% between predicted and actual outcomes under these optimized conditions, affirming the quadratic model's suitability for predicting the LMG removal process using combined EB and Na 2 S 2 O 8. To assess the environmental impact of the LMG treatment, the study applied SimaPro 9.4 with the TRACI tool, examining ten distinct environmental impact categories. The results unveiled that deionized water and Na 2 S 2 O 8 exhibited a notable impact on global warming (GW) and ecotoxicity (ET) in controlled laboratory settings. Furthermore, a comparative analysis of four scenarios shed light on the environmental implications of different energy sources. Notably, electricity generated from waste incineration demonstrated a substantial influence on all environmental indicators. In contrast, natural gas emerged as the cleanest source for electricity generation, offering a promising avenue for reducing environmental impacts. This study presents a practical method for addressing dye contaminants through the employment of EB in conjunction with Na 2 S 2 O 8 , with potential implications for broader applications. • Electron beam and persulfate were applied removing Leucomalachite Green from solution. • Box-Behnken design of response surface methodology evaluated operational variables. • Optimal conditions: 4.5 kGy absorbed dose, 1.0 mM Na 2 S 2 O 8 and pH 6. • SimaPro 9.4 with TRACI assessed environmental impact categories. • Na 2 S 2 O 8 released high environmental impact on global warming and ecotoxicity. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background and Aim: Malachite green (MG) is an organic compound which his used as a dye in textile industry. This compound is applied incorrectly and illegally in aquiculture as an antimicrobial agent. This compound has mutagenic and carcinogenic effects. Materials and Methods: In this study we determined the concentrations of MG and leucomalachite green (LMG) in the muscle tissue of 90 rainbow trouts (Oncorhynchus mykiss) collected from the local markets in Sanandaj City within a period of six months in 2018. In order to measure the residues of MG and LMG, we used enzyme-linked immunosorbent assay (ELISA) based on the European Union Decision 2002/657/EC. Results: The results showed presence of MG and LMG in all 90 samples: The residues of MG in the samples were as follows: 1-2 μg/Kg in 41 (6.45%), more than 2 μg/Kg in 45 (50%) and less than 1 μg/Kg in 4 samples (4.4%). Furthermore, the residues of LMG in the samples were as follows: more than 2 μg/Kg in 13 (45.14%), 1-2 μg/Kg in 67 (44.74%) and less than 1 μg/Kg in 10 samples (11.11%). Moreover, the limit of detection (LOD) in the method was 0.43 μg/Kg. Conclusions: It is concluded that MG is illegally applied in fish farms, which can be a threat to human health and the environment.

To develop a more sensitive immunoassay for malachite green (MG) and leucomalachite green (LMG), we identified the immunocomplex binding phage-borne peptides for use in the noncompetitive phage anti-immunocomplex assay (PHAIA). An anti-LMG monoclonal antibody (mAb) was used to select immunocomplex binding peptides from a circular random eight-amino-acid phage-displayed library. After three rounds of panning-elution, five peptides that bound the LMG-mAb immunocomplex were obtained. One of the phage-borne peptide clones that resulted in an assay with the highest sensitivity was chosen for further research. The concentration of LMG producing 50% of the saturated signal and the limit of detection of the assay were 7.02 and 0.55 ng/mL, respectively, with a linear range of 1.35 to 21.56 ng/mL. The PHAIA based on the same antibody was 16 times more sensitive compared to the competitive immunoassay. PHAIA was used to analyze LMG, MG, and two mixtures of spiked fish samples, with validation by high-performance liquid chromatography (HPLC) with fluorescence detector. Results showed a good correlation (R(2)LMG = 0.9841; R(2)MG = 0.993; R(2)Mixture = 0.9903) between the data of PHAIA and HPLC, thus the assay was an efficient method for monitoring food safety.

Biodegradation by microorganisms is a potential treatment technique of malachite green (MG) in aquaculture environments. In this study, a bacterium with high MG decolorization and biodegradation ability was isolated through enrichment culture and color‐decoloration circle method, and was identified as Klebsiella pneumoniae WA‐1 after molecular and biochemical identification. The MG biodegradation characteristics and the factors affecting the MG biodegradation ability of this strain were studied using KBH4 reduction‐high performance liquid chromatography with fluorescence detector (HPLC‐FLD) method. K. pneumoniae WA‐1 could efficiently biodegrade MG in aqueous solution without any nutrients that over 94.0% MG was biodegraded by this strain at 1–20 mg/L within 0.5 hr and 100% MG were biodegraded at 1–10 mg/L within 12 hr. Fairly stable MG biodegradation performance was observed in complex environments, including various pH, temperature, salinity, and metal ions, especially at low MG concentration. Furthermore, the presence of NaCl, Mn2+, Mg2+, or Cu2+ could enhance the MG biodegradation ability of this strain. These results indicate that K. pneumoniae WA‐1 could be used as a potential MG degradation agent in complex aquaculture environments. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objectives: Dental procedures with high-speed instruments produce large amounts of aerosols. The present study aimed to clarify whether blood-contaminated aerosols were existent and floating in air during dental procedures and to evaluate the effect of an extraoral evacuator system. Method and Materials: An extraoral evacuator system with a test filter was used for sample collection at distances from 50 cm (n = 102) and 100 cm (n =124) behind the patient. A leucomalachite green presumptive test was performed on the test filter. One or more positive reactions on the test filter was considered a positive result, and the positive ratio in each procedure was compared. To assess the effect of the extraoral evacuator, an additional extraoral evacuator was introduced, and the positive ratio during third molar extractions at 100 cm behind the patient was compared (n = 55). Results: At 50 cm from the mouth of the patient during third molar surgery, full-crown preparation, inlay cavity (Black Class II) preparation, and scaling with an ultrasonic scaler, positive results were obtained in 92% (12/13), 70% (21/30), 35% (9/26), and 33% (11/33) of cases, respectively. At a distance of 100 cm, positive ratios sustained 90% (35/39), 48% (15/31), 29% (6/21), and 12% (4/33), respectively. When the second extraoral evacuator was utilized, the positive ratio, at a distance of 100 cm, decreased significantly from 90% (35/39) to 60% (33/55) (P = .0015, chi-square test). Conclusion: This study showed that blood-contaminated aerosols can be suspended in air, even in general dental settings, and that extraoral evacuators are useful for reducing contaminated aerosols. [ABSTRACT FROM AUTHOR]

Although banned in food-producing animals, residues of malachite green (MG) and its primary metabolite, leucomalachite green (LMG), have been found in fish due to illegal use in aquaculture and the release of industrial wastewater, which represent a serious risk to food and environmental securities. This study aimed to investigate the residue depletion profile of MG and LMG in edible tissues of Nile tilapia (Oreochromis niloticus) and pacu (Piaractus mesopotamicus) cultured simultaneously under the same environmental conditions to support control measures in case of abuse. An analytical method involving QuEChERS sample preparation and liquid chromatography coupled to tandem mass spectrometry was developed, validated, and applied to quantify MG and LMG residues in fish fillets from two depletion experiments after treatment by immersion bath (MG at 0.10 mg L-1 for 60 min). During the experiment, the average water temperature was 30 ºC, while the pH was 6.9. The method is selective, precise (CV = 0.4 - 22%) and accurate (recovery 92 - 114%). The limits of detection and quantification are 0.15 and 0.5 ng g-1, respectively. In both species, the sum of MG and LMG residues were quantified up to the 32nd day post-exposure, and the concentrations were significantly higher in the pacu fillets (up to 3284 ng g-1) than in Nile tilapia (up to 432 ng g-1). The sums of MG and LMG residues were below 2 ng g-1 at 44 days and 342 days for Nile tilapia and pacu, respectively – the Minimum Required Performance Limit (MRPL) for analytical methods intended to monitor forbidden substances in food according to old European Commission guidelines. The persistence of MG residues in pacu may be attributed to its higher lipid content, which favors the accumulation of the non-polar metabolite LMG. These results provide insights into the concern about human, animal, and environmental health risks resulting from unauthorized use or aquatic contamination by industrial wastewater containing MG residues. • New insights from unauthorized drug use in aquaculture or aquatic contamination. • Residual depletion of MG and LMG in two fish species were evaluated. • MG+LMG residues were quantified up to the 32nd day post-exposure. • MG+LMG concentrations were significantly higher in the pacu. • MG+LMG prolonged persistence in pacu may be attributed to its higher lipid content. [ABSTRACT FROM AUTHOR]

A novel immunochromatographic assay (ICA) based on hyperbranched Au plasmonic blackbodies (AuPBs) with a smartphone readout was fabricated for the detection of leucomalachite green (LMG) in fish and shrimp products. The ICA was carried out in a competitive immunoassay format with AuPBs as labels. The developed AuPBs-ICA allowed for the LMG detection with a low detection limit (0.15 μg L−1) within 5 min by the smartphone reader. With the label-AuPBs ICA, the color intensity response was linearly related to the concentrations of the LMG (0.2 −1.7 μg L−1). The test line signal could be clearly distinguished at a 1.7 μg L−1 LMG as a cut-off level by the naked eye, which is lower than the conventional colloidal gold nanoparticle (2 μg L−1) and star-shaped nanoparticles (1.9 μg L−1) labeling. LMG contamination in samples was determined with the proposed AuPBs-ICA and the enzyme-linked immunosorbent (ELISA). The AuPBs-ICA results showed good agreement with those from the ELISA. The proposed AuPBs-ICA has the potential to be used as a rapid, sensitive, and simple device for the analysis of LMG residues in fish and shrimp samples. [Display omitted] • AuPBs with black color were synthesized as labels in ICA. • Highly sensitive AuPBs−ICA for the detection of LMG were established. • The cut-off level of AuPBs-ICA is lower than that of AuNPs-ICA and AuSts-ICA. • The AuPBs−ICA successfully detected LMG in fish and shrimp samples. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• Ce-CDs with reduction and enzyme-like activities was used to prepare nanozymes. • The oxidase-like activity of Ce-CDs/AuNPs for LMG can be increased by Hg (II). • Aflatoxin B 1 can inhibit the formation of Au@HgNPs as a noncompetitive inhibitor. • The applicability method for Hg (II) and aflatoxin B 1 detection were established. In this work, cerium-doped carbon dots (Ce-CDs) both as a reducing agent and template hybrid gold nanoparticles (AuNPs) with weak oxidase-like (OXD) activity was synthesized for the detection of Hg2+ and aflatoxin B 1 (AFB 1). The AuNPs can catalyze efficiently mercury ion (Hg2+) reduction to the metallic (Hg0) to form Au-Hg amalgam (Au@HgNPs). The obtained Au@HgNPs with strong OXD-like activity oxidize without Raman-active leucomalachite green (LMG) into the Raman-active malachite green (MG) and simultaneously as the SERS substrates by the formed Raman "hot spot" through MG-induced Au@HgNPs aggregation. While AFB 1 was introduced resulting in the SERS intensity decreasing due to Hg2+ with AFB 1 via carbonyl group to inhibit the aggregation of Au@HgNPs. The work paves a new path for the design of a nanozyme-based SERS protocol for tracing Hg2+ and AFB 1 residues in foodstuff analysis. [ABSTRACT FROM AUTHOR]

Background: Bloodstains often constitute the major physical evidence in criminal investi-gations. In many cases, the bloodstains found by the crime scene examiner are minute, possibly because of dissimulation efforts by the perpetrator to eliminate evidence that reveals his identity. In such cases, short tandem repeat (STR) detection procedures must be performed using the same minute bloodstain evidence on which presumptive tests had been performed earlier. In the present study, two of the most often used presumptive test reagents, phenolphthalein and leucomalachite green, were tested to determine their effects on the ability to obtain STR profiles from minute bloodstains. Methods: Dried minute bloodstains obtained from 10 donors were treated with phenolphthalein and leucomalachite green. After various times, genomic DNA was extracted from the treated samples using a QIAamp DNA Micro Kit. DNA was quantified with real-time PCR using a Quantifiler Kit. STR loci were amplified using an AmpFLSTR Identifiler Plus Kit, and the amplified products were separated via capillary electrophoresis in a 3130 Genetic Analyzer. Results: Full DNA profiles were obtained from all minute bloodstain samples treated with phenolph-thalein when extracted after intervals ranging from 1 h to 1 week. In contrast, the DNA in minute bloodstain samples treated with leucomalachite green was severely degraded, especially after relatively long intervals, leading to poor partial DNA profiles. Conclusion: Phenolphthalein is recommended as a safe presumptive test reagent for the detection of blood evidence recovered from crime scenes that might subsequently undergo DNA profiling analysis.

Malachite Green (MG) is a banned pesticide for aquaculture products. As a required inspection item, its fast and accurate determination before the products' accessing market is very important. Surface enhanced Raman scattering (SERS) is a promising tool for MG sensing, but it requires the overcoming of several problems such as fairly poor sensitivity and reproducibility, especially laser induced chemical conversion and photo-bleaching during SERS observation. By using a graphene wrapped Ag array based flexible membrane sensor, a modified SERS strategy was proposed for the sensitive and accurate detection of MG. The graphene layer functioned as an inert protector for impeding chemical transferring of the bioproduct Leucomalachite Green (LMG) to MG during the SERS detection, and as a heat transmitter for preventing laser induced photo-bleaching, which enables the separate detection of MG and LMG in fish extracts. The combination of the Ag array and the graphene cover also produced plentiful densely and uniformly distributed hot spots, leading to analytical enhancement factor up to 3.9 × 10 8 and excellent reproducibility (relative standard deviation low to 5.8% for 70 runs). The proposed method was easily used for MG detection with limit of detection (LOD) as low as 2.7 × 10 −11  mol L −1 . The flexibility of the sensor enable it have a merit for in-field fast detection of MG residues on the scale of a living fish through a surface extraction and paste transferring manner. The developed strategy was successfully applied in the analysis of real samples, showing good prospects for both the fast inspection and quantitative detection of MG. [ABSTRACT FROM AUTHOR]

Malachite green (MG) is still being used as an antiparasitic and antifungal agent in aquaculture. This is due to the fact that many stakeholders are not aware of the potential genotoxic and carcinogenic properties of MG. Since the consumption of fish in Malaysia was recorded to be the highest in Southeast Asia in 2013, it is therefore important to ensure that fish sold in the market are free of MG and its metabolite, leucomalachite green (LMG). In this study, MG and LMG residues in muscle tissue of commonly consumed fish such as red tilapia ( Oreochromis hybrid), African catfish ( Clarias gariepinus ), barramundi ( Lates calcarifer ), hybrid grouper ( Epinephelus fuscoguttatus  ×  Epinephelus lanceolatus ) and striped catfish ( Pangasius hypophthalmus ) were analysed using liquid chromatography-tandem mass spectrometry. The fish were purchased from 11 different markets in the state of Selangor, Malaysia. The results showed that the sum residues of MG and LMG in the present study ranged from 0.53 to 4.10 μg/kg with the highest residue detected in domestic striped catfish. This study indicates that MG is still being used and aquaculture stakeholders should be made aware of the judicious use of MG for the benefit of public health. [ABSTRACT FROM AUTHOR]

Arsenic contamination of drinking water is a global concern. Standard laboratory methods that are commonly used for arsenic detection in water, such as atomic absorption spectroscopy and mass spectroscopy, are not suitable for mass monitoring purposes. Autonomous microfluidic detection systems combined with a suitable colorimetric reagent could provide an alternative to standard methods. Moreover, microfluidic detection systems would enable rapid and cost efficient in situ monitoring of water sources without the requirement of laborious sampling. The aim of this study is to optimize a colorimetric method based on leucomalachite green dye for integration into a microfluidic detection system. The colorimetric method is based on the reaction of arsenic (III) with potassium iodate in acid medium to liberate iodine, which oxidizes leucomalachite green to malachite green. A rapid colour development was observed after the addition of the dye. Beer’s law was obeyed in the range between 0.07–3 µg mL−1. The detection limit and quantitation limit were found to be 0.19 and 0.64 µg mL−1, respectively.

A novel fluorescent probe based on CdTe QDs coated with molecularly imprinted polymers (MIP) was prepared for the determination of leucomalachite green (LMG) with the method of synchronous fluorescence quenching. When the wavelength interval of excitation and emission positions (Δl) was set as 340 nm, the strongest synchronous fluorescence emission of MIP-coated QDs was achieved at 260 nm, enabling the maximum fluorescent quenching of LMG because of the inner filter effect. According to this principle, a synchronous fluorescence quenching method for the rapid detection of LMG in fish was developed. MIP-coated QDs were synthesized using acrylamide (AM) and ethylene glycol dimethacrylate (EGDMA) as functional monomers and cross-linker, respectively. MIP-coated QDs with an average diameter around 67 nm were obtained at the optimum conditions (the molar ratio of 1:8:20 of LMG, AM and EGDMA, 60 mL of acetonitrile, 28 h of polymerization time). The synchronous fluorescence of MIP-coated QDs was linearly quenched by LMG at concentrations from 0.1 to 20 μmol L −1 . Detection limit was 30 nmol L −1 (3 σ , n = 9) with spiked recoveries from 94.0% to 107.8% in fish samples. The results indicate that the method can be applied to the accurate and rapid detection of LMG residues in fish samples. [ABSTRACT FROM AUTHOR]

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Malachite green (MG) has been widely used in aquaculture to treat a number of microbial and parasitic diseases. It is currently banned in the EU because of the high cytotoxicity and carcinogenic activity, which is also shared by leucomalachite green (LMG), a reduced MG metabolite that can persist in fish tissues for months. There is scant information about the ability of either compound to interact with drug metabolizing enzymes in fish. Therefore we evaluated the in vitro effects of MG and LMG (25, 50 and 100 μM) on some DMEs and glutathione (GSH) content in rainbow trout liver subfractions. LMG did not affect any of the examined parameters. In contrast, MG proved to deplete GSH and to depress to a various extent the activities of NAD(P)H cytochrome c reductase, 7-ethoxycoumarin O -deethylase, 1-naphthol uridindiphosphoglucuronyl-transferase and maximally those of 7-ethoxyresorufin O -deethylase (EROD) and glutathione S-transferase (GST) accepting 1-chloro2,4-dinitrobenzene (CDNB) as substrate. The inhibition mechanisms of EROD and GST were investigated by means of non-linear Michaelis-Menten kinetics and Lineweaver-Burk plots using 0.175–8 μM MG. The calculated IC 50 for EROD was 7.1 μM, and the inhibition appeared to be competitive (K i 2.78 ± 0.24 μM). In the case of GST, the calculated IC 50 was 0.53 μM. The inhibition was best described as competitive toward GSH (Ki 0.39 ± 0.02 μM) and of mixed-type toward CDNB (Ki 0.64 ± 0.06 μM). Our findings indicate that, contrary to LMG, MG behaves as a relatively strong inhibitor of certain liver DMEs and can reversibly bind GSH. [ABSTRACT FROM AUTHOR]

Abstract Malachite green (MG) has been used globally in aquaculture but is not registered for use in food‐producing animals in the European Union. The European Commission requested EFSA to evaluate whether a reference point for action (RPA) of 2 μg/kg for the sum of MG and its major metabolite leucomalachite green (LMG) is adequate to protect public health. Available occurrence data were not suitable for a reliable exposure assessment. The hypothetical dietary exposure was calculated, considering the RPA as occurrence value for all types of fish, fish products and crustaceans. Mean dietary exposure across different European dietary surveys and age classes would range from 0.1 to 5.0 ng/kg body weight (bw) per day. For high and frequent fish consumers, the exposure would range from 1.3 to 11.8 ng/kg bw per day. Both MG and LMG induced formation of DNA adducts in livers of rats and/or mice, and of micronuclei in mice. LMG also induced cII transgene mutations in mouse liver. MG caused a small, not dose‐related, increase in thyroid gland follicular adenomas and carcinomas, and of mammary gland carcinomas in female rats. LMG caused an increase in hepatocellular adenomas and carcinomas in female mice. Both MG and LMG may be considered as carcinogenic and as genotoxic in vivo. A lower 95% confidence limit for a benchmark response of 10% extra risk (BMDL10) of 13 mg/kg bw per day for hepatocellular adenomas and carcinomas was selected as reference point for neoplastic effects. For non‐neoplastic effects, a lower 95% confidence limit for a benchmark response of 5% extra risk (BMDL05) of 6 mg/kg bw per day was selected for the effect of MG on liver weight and of LMG on body weight. The margins of exposure were 1.1 × 106 or greater for neoplastic effects and 4.9 × 105 or greater for non‐neoplastic effects. The CONTAM Panel concluded that it is unlikely that exposure to food contaminated with MG/LMG at or below the RPA of 2 μg/kg represents a health concern.

Application of malachite green (MG) and leucomalachite green (LMG) in fish farm water causes an environmental problem. This study proposes for the first time a sensitive and convenient electrochemical impedance spectroscopy (EIS) method for determining MG and LMG by a bovine serum albumin-decorated gold nanocluster (BSA-AuNC)/antibody composite film-based immunosensor. In order to improve the analytical performance, the glassy carbon electrode (GCE) was modified with 1, 4-phenylenediamine to form a stable layer, and then, BSA-AuNCs were covalently bound to the GCE. An adequate quantity of the polyclonal antibody of LMG was immobilized onto the surface of the BSA-AuNCs by the chemical reaction of EDC/NHS. The sensors can respond to the specific target based on specific covalent bonding. The experimental parameters, such as the pH, incubating concentration, and time, have been investigated and optimized. The calibration curve for LMG was linear in the range of 0.1~10.0 ng/mL with the limit of detection (LOD) 0.03 ng/mL. Furthermore, the sum of MG and LMG was detected in fish farm water by MG reduction. The recovery was between 89.7 % and 99.2 % in spiked samples. The EC sensor method was also compared with the ELISA method and validated by the LC-MS/MS method, which proves its great promise as a field instrument for the rapid monitoring of MG and LMG pollution. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Malachite green ( MG) has been used globally in aquaculture but is not registered for use in food-producing animals in the European Union. The European Commission requested EFSA to evaluate whether a reference point for action ( RPA) of 2 μg/kg for the sum of MG and its major metabolite leucomalachite green ( LMG) is adequate to protect public health. Available occurrence data were not suitable for a reliable exposure assessment. The hypothetical dietary exposure was calculated, considering the RPA as occurrence value for all types of fish, fish products and crustaceans. Mean dietary exposure across different European dietary surveys and age classes would range from 0.1 to 5.0 ng/kg body weight (bw) per day. For high and frequent fish consumers, the exposure would range from 1.3 to 11.8 ng/kg bw per day. Both MG and LMG induced formation of DNA adducts in livers of rats and/or mice, and of micronuclei in mice. LMG also induced cII transgene mutations in mouse liver. MG caused a small, not dose-related, increase in thyroid gland follicular adenomas and carcinomas, and of mammary gland carcinomas in female rats. LMG caused an increase in hepatocellular adenomas and carcinomas in female mice. Both MG and LMG may be considered as carcinogenic and as genotoxic in vivo. A lower 95% confidence limit for a benchmark response of 10% extra risk ( BMDL10) of 13 mg/kg bw per day for hepatocellular adenomas and carcinomas was selected as reference point for neoplastic effects. For non-neoplastic effects, a lower 95% confidence limit for a benchmark response of 5% extra risk ( BMDL05) of 6 mg/kg bw per day was selected for the effect of MG on liver weight and of LMG on body weight. The margins of exposure were 1.1 × 106 or greater for neoplastic effects and 4.9 × 105 or greater for non-neoplastic effects. The CONTAM Panel concluded that it is unlikely that exposure to food contaminated with MG/ LMG at or below the RPA of 2 μg/kg represents a health concern. [ABSTRACT FROM AUTHOR]

In this study, magnetic multi-walled carbon nanotube nanoparticles were synthesized and used as the adsorbent for the sums of malachite green, gentian violet and leucomalachite green, leucogentian violet in aquaculture water samples followed by high performance liquid chromatography with fluorescence detection. This method was based on in situ reduction of chromic malachite green, gentian violet to colorless leucomalachite green, leucogentian violet with potassium borohydride, respectively. The obtained adsorbent combines the advantages of carbon nanotubes and Fe3O4 nanoparticles in one material for separation and preconcentration of the reductive dyes in aqueous media. The structure and properties of the prepared nanoparticles were characterized by transmission and scanning electron microscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy. The main parameters affecting the adsorption recoveries were investigated and optimized, including reducing agent concentration, type and amount of sorbent, sample pH, and eluting conditions. Under the optimum conditions, the limits of detection in this method were 0.22 and 0.09 ng/mL for malachite green and gentian violet, respectively. Product recoveries ranged from 87.0 to 92.8% with relative standard deviations from 4.6 to 5.9%. The results indicate that the sorbent is a suitable material for the removal and concentration of triphenylmethane dyes from polluted environmental samples. [ABSTRACT FROM AUTHOR]

Blood is significant evidence that can help an investigator solve a crime. It can link a suspect to a crime and also help in reconstructing the crime scene. Criminals often attempt to eliminate bloodstained evidence at a scene by washing it. These attempts can result in alteration, or partial or complete removal of stained areas. Many presumptive tests are used to detect the bloodstains on clothes. In this study, bloodstained fabrics were washed with commercially available and frequently used detergents. Kastle-Meyer (KM), Leucomalachite green (LMG), Tetramethylbenzidine (TMB) and Hemastix tests were used to detect the presence of blood on these washed fabrics. The Hemastix test was found to be the most sensitive to detecting the washed stains on all cloths. The Leucomalachite green test was found to be the least sensitive. The ability of a fabric to retain blood after washing depends not only upon the chemistry and manufacturing of the fabric but also on the type of detergent. The time of immersion of the fabric with detergent also affects the removal of stains from fabrics. Ariel showed the best results in removing bloodstains from all fabrics. Cotton polyester and khaddar showed the maximum retention of blood after washing with either of the detergents, whereas silk polyester had the minimum ability to hold bloodstains. [ABSTRACT FROM PUBLISHER]

In order to develop multi-residues rapid detection, the bispecific aptamers against malachite green (MG) and leucomalachite green (LMG) were isolated by the capture systematic evolution of ligands by exponential enrichment (Capture-SELEX). After thirteen rounds of selection, the enriched ssDNA pools were sent for high-throughput sequencing. Nine aptamer candidates (A1-A9) were picked out to test their specificity by gold nanoparticles (AuNPs) colorimetric assay. Three aptamers (A2, A3, A5) with good selectivity were truncated to verify their affinity by fluorescence assay. Finally, three truncated aptamers (A2-a, A3-a, A5-a) with bispecificity and high affinity were identified. For LMG, the dissociation constant (Kd) of them were 8.4 ± 0.8 nM, 8.2 ± 1.2 nM, and 13.7 ± 1.4 nM, respectively. For MG, Kd of them were 3.4 ± 0.3 μM, 2.3 ± 0.2 μM, 3.0 ± 0.2 μM. Among them, A3-a is the best. Our work will provide novel probes for the development of multi-residues rapid detection as well as opportunities for multiple target aptamer discovery. [Display omitted] • The bispecific aptamers against MG and LMG were successfully isolated by Capture-SELEX through 13 rounds of selection. • Three bispecific aptamers (A2-a, A3-a, A5-a) exhibited high affinity. They showed nM Kd for LMG, and μM Kd for MG. • A3-a is the best, Kd is 8.2 ± 1.2 nM for LMG and 2.3 ± 0.2 μM for MG. [ABSTRACT FROM AUTHOR]

A novel spectrofluorimetric method has been developed for the simultaneous determination of leucomalachite green (LMG), leucocrystal violet (LCV), malachite green (MG) and crystal violet (CV) by combining the sensitivity of molecular fluorescence and the selectivity of the second-order calibration. Residues of LMG, LCV, MG and CV were simultaneously extracted from fish and shrimp muscle with acetonitrile. The non-fluorescent CV and MG were then reduced to the corresponding fluorescent LMG and LCV by reacting with sodium borohydride. After preconcentration with dispersive liquid–liquid microextraction technique, the extracts were analyzed by using excitation–emission matrix fluorescence coupled with second-order calibration methods based on parallel factor analysis (PARAFAC) and alternating trilinear decomposition (ATLD) algorithms. The limits of detection obtained were 2.21–2.65 ng g −1 by PARAFAC and 2.30–2.86 ng g −1 by ATLD, respectively. The developed method was successfully applied to simultaneous determination of the four analytes in grass carp and shrimp samples with recoveries of 90.53–103.03% for PARAFAC and 90.40–102.75% for ATLD. The accuracy of this novel method was also verified by high performance liquid chromatography. [ABSTRACT FROM AUTHOR]

Background Bloodstains often constitute the major physical evidence in criminal investi-gations. In many cases, the bloodstains found by the crime scene examiner are minute, possibly because of dissimulation efforts by the perpetrator to eliminate evidence that reveals his identity. In such cases, short tandem repeat (STR) detection procedures must be performed using the same minute bloodstain evidence on which presumptive tests had been performed earlier. In the present study, two of the most often used presumptive test reagents, phenolphthalein and leucomalachite green, were tested to determine their effects on the ability to obtain STR profiles from minute bloodstains. Methods Dried minute bloodstains obtained from 10 donors were treated with phenolphthalein and leucomalachite green. After various times, genomic DNA was extracted from the treated samples using a QIAamp DNA Micro Kit. DNA was quantified with real-time PCR using a Quantifiler Kit. STR loci were amplified using an AmpFLSTR Identifiler Plus Kit, and the amplified products were separated via capillary electrophoresis in a 3130 Genetic Analyzer. Results Full DNA profiles were obtained from all minute bloodstain samples treated with phenolph-thalein when extracted after intervals ranging from 1 h to 1 week. In contrast, the DNA in minute bloodstain samples treated with leucomalachite green was severely degraded, especially after relatively long intervals, leading to poor partial DNA profiles. Conclusion Phenolphthalein is recommended as a safe presumptive test reagent for the detection of blood evidence recovered from crime scenes that might subsequently undergo DNA profiling analysis. [ABSTRACT FROM AUTHOR]

Surface-enhanced resonance Raman scattering (SERRS) coupled with gold nanospheres was applied for rapid analysis of the hazardous substances malachite green (MG) and leucomalachite green (LMG) in fish muscle tissues. The lowest concentration of MG that could be detected was 0.5 ng mL −1 with high linear correlation ( R 2 = 0.970–0.998) between MG concentration and intensities of characteristic Raman peaks. A simplified sample preparation method taking less than 1 h for recovering MG and LMG in fish fillets was developed for SERRS analysis, and 4–8 samples could be handled in parallel. MG and LMG could be detected in extracts of tilapia fish fillets at as low as 2 ng g −1 with SERRS and a simple principle component analysis method. For six other fish species, the lowest detectable concentration of MG ranged from 1 ng g −1 to 10 ng g −1 . This study provides a new sensitive approach for the detection of trace amounts of the prohibited drugs MG and LMG in muscle food, which has the potential for rapidly screening a large number of samples. [ABSTRACT FROM AUTHOR]