Tangeretin Supplementation Mitigates the Aging Toxicity Induced by Dietary Benzo[a]pyrene Exposure with Aberrant Proteostasis and Heat Shock Responses in Caenorhabditis elegans.

Benzo[a]pyrene (BaP) is a common food contaminant that can impair organismal aging. Tangeretin (TAN) may mitigate aging toxicities as a dietary supplement. This study used Caenorhabditis elegans to investigate the effects of chronic exposure to BaP on aging and to determine whether TAN supplementation could alleviate BaP-induced toxicity. Early life exposure to BaP (10 µM) significantly inhibited growth by 5%, and exposure to 0.1 to 10 µM BaP impaired C. elegans motility, resulting in a 3.4-6.5% reduction in motility. Chronic exposure to BaP (10 µM) age-dependently aggravated aberrant protein aggregation (7% increase) and shortened the median lifespan of the worms from 20 to 16 days. In addition, BaP worsened the age-dependent decline in motility and pharyngeal pumping, as well as the accumulation of reactive oxygen species. Furthermore, exposure to BaP resulted in significantly higher relative transcript levels of approximately 1.8-2.0-fold for the hsp-16.1, hsp-16.2, hsp-16.49, and hsp-70 genes. Stressed worms exposed to BaP exhibited significantly lower survival under heat stress. Dietary TAN supplementation alleviated the BaP-induced decline in motility, pumping, and poly-Q accumulation and restored heat shock proteins' transcript levels. Our findings suggest that chronic BaP exposure adversely affects aging and that TAN exposure mitigates the BaP-induced aging toxicity.

Effects of a new nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on nitrate and potassium leaching in two soils.

In this study, soil column was used to study the new nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on nitrate (NO3(-)-N) and potassium (K) leaching in the sandy loam soil and clay loam soil. The results showed that DMPP with ammonium sulphate nitrate (ASN) ((NH4)2SO4 and NH4NO3) or urea could reduce NO3(-)-N leaching significantly, whereas ammonium (NH4(+)-N) leaching increased slightly. In case of total N (NO3(-)-N+NH4(+)-N), losses by leaching during the experimental period (40 d) were 37.93 mg (urea), 31.61 mg (urea+DMPP), 108.10 mg (ASN), 60.70 mg (ASN+DMPP) in the sandy loam soil, and 30.54 mg (urea), 21.05 mg (urea+DMPP), 37.86 mg (ASN), 31.09 mg (ASN+DMPP) in the clay loam soil, respectively. DMPP-amended soil led to the maintenance of relatively high levels of NH4(+)-N and low levels of NO3(-)-N in soil, and nitrification was slower. DMPP supplementation also resulted in less potassium leached, but the difference was not significant except the treatment of ASN and ASN+DMPP in the sandy loam soil. Above results indicate that DMPP is a good nitrification inhibitor, the efficiency of DMPP seems better in the sandy loam soil than in the clay loam soil and lasts longer.