Reduced nitrogen fertilization from pre-flowering to pre-veraison alters phenolic profiles of Vitis vinifera L. Cv. Cabernet Gernischt wine of Yantai, China.

Nitrogen (N) fertilization is important for grape growth and wine quality. Unreasonable N fertilizer application affects wine growth and has a negative impact on wine quality. Therefore, it is essential to address the mismatch between N application and wine composition. To regulate vine growth and improve grape and wine quality, Cabernet Gernischt (Vitis vinifera L.) grapevines were subjected to lower levels of N, compared to normal N supply treatments, during the grape growing seasons of 2019 and 2020 in the wine region of Yantai, China. The effects of reduced N application from pre-boom to pre-veraison on vine growth, yield and composition of grapes, and dry red wine anthocyanin and non-anthocyanin phenolic compound content were studied. We found that reduced N application significantly decreased dormant shoot fresh mass and yield. However, the effect of N application on fruit ripening depended on the season. Nitrogen-reduction treatment significantly improved wine phenolic parameters, including total phenolics, tannins, and anthocyanins, and enhanced most of the individual anthocyanins and some non-anthocyanin phenolics, especially stilbenes, including piceatannol, trans-resveratrol, and polydatin, regardless of the season. Overall, our findings highlight the importance of reducing N application during the grape growing season in order to modify the wine phenolic profiles.

Evolution of volatile profile and aroma potential of 'Gold Finger' table grapes during berry ripening.

BACKGROUND: 'Gold Finger' is a grape cultivar with a finger-like shape and a milk flavor. The process by which its aroma profile evolves during ripening is unclear. Thus, changes in the free and bound volatile compounds present in 'Gold Finger' grapes during ripening were investigated using headspace sampling-solid-phase microextraction-gas chromatography-mass spectroscopy (HS-SPME-GC-MS). RESULTS: A total of 83 volatile aroma components were identified in the grapes, with aldehydes, esters, acids, and alcohols being the main components. The total aroma compound content exhibited significant differences between the bound and free forms. The total content of bound volatile compounds did not change significantly during fruit development, although the free aroma compound content was significantly higher than the bound content. The total content of free aldehydes, free alcohols, bound norisoprenoids, and ketones gradually increased for up to 70 days after flowering (DAF), while the total free ester, terpene, and acid content decreased. The characteristic aroma compounds of 'Gold Finger' grapes were identified as hexanal, (E)-2-hexenal, and ethyl hexanoate. CONCLUSIONS: These results give a foundation for the further development of 'Gold Finger' grapes and provide a theoretical basis for the selection and breeding of novel aromatic grape varieties. © 2021 Society of Chemical Industry.

Cluster bagging promotes melatonin biosynthesis in the berry skins of Vitis vinifera cv. Cabernet Sauvignon and Carignan during development and ripening.

Melatonin, a tryptophan derivative, is an important functional component in grape berries. We investigated the effect of cluster bagging on melatonin biosynthesis in the berries of two wine grape cultivars, Cabernet Sauvignon and Carignan, during fruit development and ripening. Cluster bagging delayed fruit coloring and ripening, and bag-treated berries of both grape cultivars synthesized more melatonin and most of the precursor compounds including L-tryptophan, N-acetylserotonin, tryptamine, and serotonin compared to those exposed to light (control) conditions. Interestingly, 5-methoxytryptamine was only detected in the berries of Carignan and not of Cabernet Sauvignon, both in the cluster bagging and control groups. In addition, melatonin and most of its precursors, decreased after veraison. VvSNAT1 and VvT5H expression levels were positively correlated with melatonin content. Our findings suggested that melatonin synthesis pathways differ among grape cultivars, and that VvSNAT1 and VvT5H may show key regulatory roles in the melatonin synthesis of grape berries.

Diagnostic performance of minimum apparent diffusion coefficient value in differentiating the invasive breast cancer and ductal carcinoma in situ.

BACKGROUND: This study is to explore the role of the minimum apparent diffusion coefficient (ADC-min) value in the diagnosis of invasive breast cancer and ductal carcinoma in situ (DCIS). MATERIALS AND METHODS: A total of 196 breast cancer patients with pathologically verified lesions were included. They received diffusion-weighted imaging and dynamic breast magnetic resonance imaging before the pathological confirmation. The ADC-min value and its relationship with invasive ductal carcinoma (IDC), IDC-DCIS, and DCIS were analyzed. RESULTS: Of the 196 breast cancer patients, there were 115 (58.67%) cases of IDC, 53 (27.04%) cases of IDC-DCIS, and 28 (14.29%) cases of DCIS. The mean ADC-min values for IDC, IDC-DCIS, and DCIS were (0.96 ± 0.16) × 10-3, (1.10 ± 0.13) × 10-3, and (1.24 ± 0.17) × 10-3 mm 2/s, respectively. The mean ADC-min value of IDC was significantly lower than that of IDC-DCIS and that of IDC-DCIS was significantly lower than that of DCIS (P < 0.01). The mean ADC-min value was also significantly different between invasive cancer and DCIS (P < 0.01). The mean ADC-min value can be used in the differential diagnosis of DCIS, with a cutoff point of 1.02 × 10-3 mm 2/s (sensitivity of 92.9% and specificity of 57.7%). CONCLUSIONS: The ADC-min values are significantly different among IDC, IDC-DCIS, and DCIS, with the lowest ADC-min values in IDC, followed by IDC-DCIS and DCIS. The ADC-min maybe used as a promising parameter to differentiate DCIS and invasive cancer.