Nanfack V.D. Carole,Lina Sheng,Jian Ji,Shang Wu,Yinzhi Zhang,Xiulan Sun
Ensuring the safety and high quality of food relies on promptly and clearly identifying foodborne diseases, including Salmonella . Nucleic acid testing plays an important role in ensuring food safety. Commercially available high-throughput molecular extraction technologies in-field application is limited as they are reliant on specialized and expensive equipment. The 96-well microplate recycling through biopolymer inner surface coating, was confirmed with FTIR, XRD, and XPS. Once optimized the DNA extraction protocol was equipment-free, user and eco-friendly while reducing sample contamination. Using the biopolymer microplate, the extraction and direct LAMP amplification of Salmonella spp. from milk samples were assessed. The gDNA had an average 260/280 ratio of 1.97, with a DNA yield of 16.88 ± 5.40 μg·mL -1 from 9 × 10 10 CFU·mL -1 Salmonella . Subsequently, using acid chrome K we visually detected the presence of Salmonella . The quantity of bacteria was correlated to the increase in the blue intensity of the color indicator. A detection limit of 1.54 CFU·mL -1 was achieved with good specificity and sensitivity in an equipment free setting. This study successfully established a 96-well plate-based high-throughput equipment free DNA extraction method. The methods enable the high-throughput extraction and amplification of 96 samples concomitantly within 1hr 30 min corresponding respectively to a total of 1536 and 768 samples within a working day treated by a researcher without the use of specialized and expensive equipment. The polymeric modified microplate was used for high-throughput DNA extraction and direct molecular amplification for pathogen detection. High-throughput DNA extraction no longer requires cumbersome equipment.
N 6 -acetyl- L - lysine residue is abundant in dietary protein but little is known about its potential influences on the diet-consumers. Herein, it is reported that Lysyl-tRNA synthetase (KARS) mediates co-translational deposition of diet-derived N 6 -acetyl- L -lysine (AcK) in nascent proteins to contribute to the acetylome in cells. Acetylated dietary protein is a direct source of AcK that can widely and substantially regulate the acetylome in multiple organs of mice. By analyzing the mechanisms underlying AcK contributing to the acetylome in mammalian cells, it is found that KARS can utilize AcK as an alternative substrate to produce N 6 -acetyl- l -lysyl-tRNA. The crystal structure of KARS in complex with AcK at 2.26 Å resolution shows that AcK shares the same substrate-binding pocket as L -lysine, allowed by a sidechain flip of Tyr499. The generated N 6 -acetyl- L -lysyl-tRNA introduces AcK into growing nascent polypeptide and results in protein acetylation, including the regions buried inside folded proteins that are post-translational modification (PTM)-inaccessible and functionally important. This undocumented protein modification mechanism is inherently different from PTM and termed as co-translational modification (coTM). It is expected to extend the repertoire of acetylome and improve the understanding of protein modification mechanisms in cells.
危险品化学品经营许可证（带存储）