China
Africa
Explore chapters and articles related to this topic
Determination of Metals in Soils
Published in T. R. Crompton, Determination of Metals and Anions in Soils, Sediments and Sludges, 2020
The pH range of bromophenol blue is 3.0–4.6 and its acidic and basic forms are yellow and blue, respectively. Fig. 2.14 shows the absorption spectra of the acidic and basic forms of bromophenol blue measured against water over the 420–660nm range. The absorption spectrum of the basic form has a maximum at 580nm, whereas the absorption of the acidic form is almost negligible at this wavelength.
Applications of aged powders of spray-dried whey protein isolate and ascorbic acid in the field of food safety
Published in Drying Technology, 2023
Chao Zhong, Songwen Tan, Zelin Zhou, Xia Zhong, Timothy Langrish
Microbial contamination causes reductions in food shelf life, and it increases the possibility of food-borne illnesses. For consumers, the changed texture, flavor and color of the food may be unacceptable. To deal with this problem, some food sensors[6–8] have been developed, which also help to mitigate food waste.[9] With the help of specific reactions, food sensors may be used to indicate food quality or safety. The pH of the chemical environment for foods can be changed by microbial spoilage.[10] When food is stored, transported or distributed, a pH indicator can be used to monitor its pH condition and give information about its quality. An indicator may respond through visible color development in response to pH changes.[11,12] The pH may be detected using an indicator, and a simple, low-cost, rapid and environmentally friendly sensor is helpful.[5] In order to detect volatile compounds that are acidic or basic, changes in the visual appearance of some pH dyes may be considered. Colorimetric pH indicator dyestuffs may be used, including bromothymol blue, bromophenol blue, bromocresol purple, methyl red, bromocresol green, methyl orange, methyl yellow, phenol red.[13] As pH indicators, methyl red (MR) and bromocresol purple (BCP) are toxic.
Activated sludge and UV-C254 for Sapovirus, Aichivirus, Astrovirus, and Adenovirus processing
Published in International Journal of Environmental Health Research, 2023
Chourouk Ibrahim, Salah Hammami, Nesserine khelifi, Pierre Pothier, Abdennaceur Hassen
HAstVs and AiVs are detected by conventional RT-PCR using the pair of primers (Mon 244/Mon 245) and (Aichi 6261/Aichi 6779) to amplify a 413 and 519 bp fragment of the genes coding for the capsid precursor ORF2 and the 3 CD junction of RNA-dependent-RNA polymerase; respectively; as recommended by Noel et al. (1995) and Yamashita et al. (2000). All the reactions of conventional RT-PCR are carried out using a Qiagen One-Step RT-PCR kit according to the manufacturer’s instructions and with amplification cycles described by the authors of each pair of primers (Noel et al. 1995; Yamashita et al. 2000). On the other side, HAdVs are detected by nested PCR using the primer pairs (Adv-HEX1DEG/Adv-HEX2DEG) and (Adv-HEX3DEG/Adv – HEX4DEG) to amplify the gene coding for the Adenoviruses 2 hexon (Allard et al. 2001). The Two PCRs are run using a Qiagen PCR kit according to the manufacturer’s instructions and with amplification cycles defined by the authors of each primer pair (Allard et al. 2001; Ibrahim et al. 2018). After amplification, 20 μL of PCR product of HAstVs, AiVs, and HAdVs mixed with 2 μL of Bromophenol Blue are revealed by 2% agarose gel electrophoresis (30 min at 140 volts) containing 4 μL of BET solution at 0.4 μg/mL final in TBE buffer (1×). All the amplified viral DNA products of HAstVs, AiVs, and HAdVs are visualized under UV image analyzers. SaVs are only detected by Real-time RT-PCR using SaV124F, SaV1245R primers, and SaV124TP probe to amplify the gene encoding the polymerase region (Oka et al. 2006).
Role of heavy metal tolerant rhizosphere bacteria in the phytoremediation of Cu and Pb using Eichhornia crassipes (Mart.) Solms
Published in International Journal of Phytoremediation, 2022
Raisa Kabeer, Sylas V. P., Praveen Kumar C. S., Thomas A. P., Shanthiprabha V., Radhakrishnan E. K., Baiju K. R.
Heavy metal tolerant bacteria were identified by DNA extraction, followed by a Polymerase Chain Reaction (PCR) analysis. The bacterial 16S rRNA fragment was amplified from the extracted genomic DNA by using a universal primer, 8F (5′-AGAGTTTGATCMTGG-3′), and reverse primer, 1492R (5′-ACCTTGTTACGACTT-3′). The PCR was performed in a final reaction volume of 50μL in 200μL capacity thin-wall PCR tube. After the initial denaturation for five minutes at 95 °C, there were 29 cycles of denaturation at 94 °C for 30s, annealing at 58 °C for 30s, with extension at 72 °C for 45s and final extension at 72 °C for 10min. PCR was carried out in ABI3730xl Genetic Analyzer (Applied Biosystems, USA). The PCR product was analyzed by agarose gel electrophoresis in 1×TBE (Tris-Borate-EDTA; electrophoresis buffer) with Bromophenol blue as a loading dye. The agarose gel was viewed on a UV trans-illuminator and the PCR products were sequenced by ABI3730xl Genetic Analyzer (Applied Biosystems, USA). The sequences obtained were submitted to the Basic Local Alignment Search Tool (BLAST; http://www.ncbi.nlm.nih.gov/BLAST) at the National Center for Biotechnology Information (NCBI) to determine the percentage similarity with already identified 16 S rRNA gene sequences from the GenBank database. The sequences were deposited in the GenBank with their allotted accession numbers.