Validation and measurement uncertainty of analytical methods for various azo dye adulterants in Curcuma longa L.

Food adulteration involving the illegal addition of dyes to foodstuffs has become an alarming issue in recent years. This study developed and validated a high-performance liquid chromatography (HPLC)-DAD (diode array detector) method for the simultaneous determination of nine azo dyes (Butter Yellow, Sudan Orange G, Para Red, Sudan I, Sudan II, Sudan III, Sudan IV, Sudan Red 7B, and Scarlet 808). Moreover, a qualitative analysis method using liquid chromatography-tandem mass spectrometry was developed to more accurately identify peaks detected in HPLC-DAD. The calibration curve represented good linearity (r2 ≥ 0.9998) over the measured concentration range of 0.5-25 mg/kg. limit of detection and limit of quantification were 0.01-0.04 and 0.04-0.12 mg/kg, respectively. Accuracy and precision were 96.0-102.6 and 0.16-2.01 (relative standard deviation%), respectively. Additionally, the measurement uncertainty and HorRat value were estimated. Several Curcuma longa L. distributed in Korea were collected and monitored for azo dye contaminants. PRACTICAL APPLICATION: The proposed HPLC-DAD method represents a significant advancement in the field, offering a reliable means of quantifying azo dyes and identifying their presence even at trace levels in adulterated turmeric. This not only contributes to ensuring the safety and integrity of turmeric products but also establishes precedent for robust analytical techniques in addressing food safety challenges.

Tho2-mediated escort of Nrd1 regulates the expression of aging-related genes.

The relationship between aging and RNA biogenesis and trafficking is attracting growing interest, yet the precise mechanisms are unknown. The THO complex is crucial for mRNA cotranscriptional maturation and export. Herein, we report that the THO complex is closely linked to the regulation of lifespan. Deficiencies in Hpr1 and Tho2, components of the THO complex, reduced replicative lifespan (RLS) and are linked to a novel Sir2-independent RLS control pathway. Although transcript sequestration in hpr1Δ or tho2Δ mutants was countered by exosome component Rrp6, loss of this failed to mitigate RLS defects in hpr1Δ. However, RLS impairment in hpr1Δ or tho2Δ was counteracted by the additional expression of Nrd1-specific mutants that interacted with Rrp6. This effect relied on the interaction of Nrd1, a transcriptional regulator of aging-related genes, including ribosome biogenesis or RNA metabolism genes, with RNA polymerase II. Nrd1 overexpression reduced RLS in a Tho2-dependent pathway. Intriguingly, Tho2 deletion mirrored Nrd1 overexpression effects by inducing arbitrary Nrd1 chromatin binding. Furthermore, our genome-wide ChIP-seq analysis revealed an increase in the recruitment of Nrd1 to translation-associated genes, known to be related to aging, upon Tho2 loss. Taken together, these findings underscore the importance of Tho2-mediated Nrd1 escorting in the regulation of lifespan pathway through transcriptional regulation of aging-related genes.

Validation of avenanthramide and other phenolic compounds in oats and sprouted oats and their antimicrobial properties against Escherichia coli O157:H7.

Oat contains a variety of phenolic compounds, including avenanthramides, which are found only in oats. This study was conducted to establish the quantitative analysis of seven phenolic compounds in oat powders and sprouted oat powders and validate an efficient high-performance liquid chromatography (HPLC) method. All calibration curves represented good linearity (R 2 ≥ 0.9997) in the concentration range (0.5-50 mg/kg) with LOD and LOQ of 0.01-0.21 and 0.02-0.64 mg/kg, respectively. Intra-day accuracy (%) and precision (%RSD) were 90.7-103.8% and 1.5-4.9%, respectively. Inter-day accuracy (%) and precision (%RSD) were 90.4-107.9% and 2.2-4.8%, respectively. Moreover, relative expanded measurement uncertainty results complied with CODEX guideline. In addition, selected oat and sprouted oat powder extracts showed anti-microbial activities against Escherichia coli O157:H7. These results demonstrated that this HPLC method is suitable for the qualification and quantification of seven phenolic compounds in oat and sprouted oat. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-022-01099-8.

Sus1 maintains a normal lifespan through regulation of TREX-2 complex-mediated mRNA export.

Eukaryotic gene expression requires multiple cellular events, including transcription and RNA processing and transport. Sus1, a common subunit in both the Spt-Ada-Gcn5 acetyltransferase (SAGA) and transcription and export complex-2 (TREX-2) complexes, is a key factor in coupling transcription activation to mRNA nuclear export. Here, we report that the SAGA DUB module and TREX-2 distinctly regulate yeast replicative lifespan in a Sir2-dependent and -independent manner, respectively. The growth and lifespan impaired by SUS1 loss depend on TREX-2 but not on the SAGA DUB module. Notably, an increased dose of the mRNA export factors Mex67 and Dbp5 rescues the growth defect, shortened lifespan, and nuclear accumulation of poly(A)+ RNA in sus1Δ cells, suggesting that boosting the mRNA export process restores the mRNA transport defect and the growth and lifespan damage in sus1Δ cells. Moreover, Sus1 is required for the proper association of Mex67 and Dbp5 with the nuclear rim. Together, these data indicate that Sus1 links transcription and mRNA nuclear export to the lifespan control pathway, suggesting that prevention of an abnormal accumulation of nuclear RNA is necessary for maintenance of a normal lifespan.

The Spt7 subunit of the SAGA complex is required for the regulation of lifespan in both dividing and nondividing yeast cells.

Spt7 belongs to the suppressor of Ty (SPT) module of the Spt-Ada-Gcn5-acetyltransferase (SAGA) complex and is known as the yeast ortholog of human STAF65γ. Spt7 lacks intrinsic enzymatic activity but is responsible for the integrity and proper assembly of the SAGA complex. Here, we determined the role of the SAGA Spt7 subunit in cellular aging. We found that Spt7 was indispensable for a normal lifespan in both dividing and nondividing yeast cells. In the quiescent state of cells, Spt7 was required for the control of overall mRNA levels. In mitotically active cells, deletion of the SPT module had little effect on the recombination rate within heterochromatic ribosomal DNA (rDNA) loci, but loss of Spt7 profoundly elevated the plasmid-based DNA recombination frequency. Consistently, loss of Spt7 increased spontaneous Rad52 foci by approximately two-fold upon entry into S phase. These results provide evidence that Spt7 contributes to the regulation of the normal replicative lifespan (RLS) and chronological lifespan (CLS), possibly by controlling the DNA recombination rate and overall mRNA expression. We propose that the regulation of SAGA complex integrity by Spt7 might be involved in the conserved regulatory pathway for lifespan regulation in eukaryotes.