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Biochemical Methods of Studying Hepatotoxicity
Published in Robert G. Meeks, Steadman D. Harrison, Richard J. Bull, Hepatotoxicology, 2020
Prasada Rao S. Kodavanti, Harihara M. Mehendale
Inorganic phosphate (Pi) assay with malachite green is one of the various methods available to measure Pi (Fiske and Subbarow, 1925; Lowry and Lopez, 1946; Carter and Karl, 1982). This method is adapted from Carter and Karl (1982), which has several advantages over the other methods. The principle involved in this method is that the Pi liberated during substrate hydrolysis combines with molybdate in acidic media forming phosphomolybdate complex. This reacts with malachite green forming a colored complex. Sulfuric acid reacts with the uncomplexed malachite green, reducing the background color and eliminating the contribution of Pi produced from any subsequent nonenzymatic hydrolysis of substrate. This method has several advantages over the other methods reported in the literature. For example, (1) the color developed is stable for several hours; (2) the sensitivity is approximately 1 nmol Pi, and (3) proteins up to 0.1 mg/ml do not affect the linearity of the standard curve.
Invisible borders
Published in Milton J. Lewis, Kerrie L. MacPherson, Public Health in Asia and the Pacific, 2007
Despite such promising initiatives to strengthen cross-border cooperation and coordination, the chronicle of food hygiene goes on. Problems continue with imported fish from Guangdong contaminated with either banned chemicals or antibiotics (South China Morning Post 10 November 2005, 13 June, 8 July and 20 December 2006). In November 2006, fresh water garoupa containing malachite green prompted a temporary ban on fresh water fish imports from China, which was extended to saltwater fish two weeks later after samples were found to contain the antibiotic nitrofuran. Hong Kong's testing standards were criticized by the Guangdong Inspection and Quarantine Bureau as ‘vague’ and the state-owned company that controls the trade in fresh water fish in Guangdong refused to resume sales to Hong Kong. Fish farmers claimed that 10,000 workers in the industry were ‘gravely affected’ with losses of HKD 150 million (South China Morning Post 27 November and 8 December 2006). Eggs were found tainted by the industrial dye, Sudan Red, and tests on fruits and vegetables imported from Guangdong revealed that 25% were contaminated with banned pesticides, with 50% of the strawberries having an excessive lead content (South China Morning Post 21 December 2006).
The biology of parasites from the genus Argulus and a review of the interactions with its host
Published in G. F. Wiegertjes, G. Flik, Host-Parasite Interactions, 2004
Peter D. Walker, Gert Flik, Sjoerd E. Wendelaar Bonga
There are numerous options available for the control, prevention and treatment of Argulus infections. Many traditional treatment methods rely on the use of toxic chemicals such as malachite green or other insecticide-type chemicals. The damaging effects of many of these chemicals on wildlife are now widely recognized and as a result many countries now prohibit their use. There is also an increasing pressure from consumers for food fish that have not been subjected to chemical treatments. The wide range of chemical treatments available for infections of Argulus spp. is well documented. Due to the extensive literature available on this topic no effort is made here to discuss them in detail. The author therefore refers the reader to selected texts (e.g. Kabata, 1970, 1985; Lester and Roubal, 1995; Van Duijn Jnr, 1973); Williams, 1997).
A polypeptide inhibitor of calcineurin blocks the calcineurin-NFAT signalling pathway in vivo and in vitro
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2022
Ping Wang, Wenying Li, Yumeng Yang, Na Cheng, Yuchen Zhang, Nan Zhang, Yanxia Yin, Li Tong, Zhimei Li, Jing Luo
Pep4 specifically binds to CN and inhibits the activity of CN by occupying the corresponding binding site of CN. We used RII (DLDVPIPGRFDRRVpSVAAE) as the substrate to detect the effect of pep4 on CN enzyme activity in vitro based on malachite green colorimetry. Given that CN is highly expressed in the brain, we used the protein extract of the mouse brain as the crude enzyme extract. The synthesised peptide pep4 was incubated with the crude extract of mouse brain enzyme, and the substrate RII was added for the dephosphorylation reaction. Finally, malachite green was added for colour development. The results showed that pep4 inhibited CN enzyme activity in a dose-dependent manner (Figure 2(A)). The IC50 of pep4 was 5.1 nM, indicating that pep4 had a strong inhibitory effect on CN.
A study of Rose Bengal against a 2-keto-3-deoxy-d -manno-octulosonate cytidylyltransferase as an antibiotic candidate
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2020
Suwon Kim, Seri Jo, Mi-Sun Kim, Dong Hae Shin
The screening of about two hundred chemical compounds (Supplementary Table 1) was performed with a malachite green assay method which is a photometric method31. The principle of this method is: when KdsBs transfer the cytidine 5′-monophosphate (CMP) moiety from cytidine 5′-triphosphate (CTP) to KDO, CMP-KDO, and pyrophosphate (PPi) are produced. PPi was decomposed into two phosphates by inorganic pyrophosphatase (IPP) and phosphates were measured by the malachite green method. CTP and KDO purchased from Sigma (St. Louis, MO) were used as a real substrate. A colour reagent of the malachite green method for phosphate detection was a mixture of ammonium molybdate ((NH4)6Mo7O24), malachite green solution and Tween 20 in the ratio 1:3:0.1. The mixture was filtered through a 0.20 μm PVDF syringe filter (Younginfrontier Inc., Seoul, Republic of Korea) and allowed to stand at room temperature (RT) for 1 h before use. The probability of inhibitory function of each chemical was investigated by detecting the difference in absorbance between the reaction mixtures with and without KdsBs.
Ocular toxicity due to colours used during holi celebration in India: correlation of clinical findings with the anterior segment OCT
Published in Cutaneous and Ocular Toxicology, 2019
Amar Pujari, Aswini Behera, Ritika Mukhija, Rohan Chawla, Suresh Yadav, Namrata Sharma
Ocular toxicity due to colours used during Holi festival celebration has been noted previously on few occasions1–5. In the past the colours used were derived from natural precursors. Presently with a large population playing Holi and growth of the chemical industry, artificial chemical agents have replaced the natural precursors. The harmful toxic substances within these colours include malachite green, gentian violet, rhodamine, lead, mercury sulphate, silica, copper sulphate, and others. The toxic effect on the ocular tissue of some of these chemicals has been studied. The initial work on Holi ocular toxicity was performed by Ghose et al. in 19941. An important toxic material among the studied colours is malachite green, which is a triarylmethane with good water solubility and is commonly used in the dyeing industry4.