Silicates of Potassium and Aluminium (Kaolin); Comparative Foliar Mitigation Treatments and Biochemical Insight on Grape Berry Quality in Vitis vinifera L. (cv. Touriga National and Touriga Franca).

Grapevine physiology is influenced by several environmental factors, such as temperature, precipitation, potential evapotranspiration, and sunshine hours. Due to climatic changes, effects in grapevine physiology and consequently on the grape berry composition and quality have been observed. This work aims to make a comparative study of the effect of foliar mitigation treatment with kaolin (5%) and potassium silicates (0.1% and 0.05%) on the grape berry quality; namely on berry weight, pH, probable alcohol, total phenolics, tannins, total anthocyanins, monomeric anthocyanins, calcium, potassium, and magnesium composition from Portuguese grapevines (Vitis vinifera L. cv. Touriga Nacional and Touriga Franca). The results suggested that the phenolic composition and anthocyanin content differs between treatments while other parameters showed distinct behavior among the different applications. Qualitative parameters observed in the present study suggested non-significant changes upon both the applications.

Chitosan Upregulates the Genes of the ROS Pathway and Enhances the Antioxidant Potential of Grape (Vitis vinifera L. 'Touriga Franca' and 'Tinto Cão') Tissues.

Chitosan is an environmentally-friendly active molecule that has been explored for numerous agricultural uses. Its use in crop protection is well-known, however, other properties, such as bioactivity, deserve attention. Moreover, the modes of actions of chitosan remain to be elucidated. The present study assessed the levels of total phenolic compounds, the antioxidant potential, and the expression of reactive oxygen species (ROS) scavenging genes in the berries (skins and seeds), leaves, cluster stems, and shoots upon chitosan application on two red grapevine varieties (Touriga Franca and Tinto Cão). The application of chitosan on the whole vine before and after veraison led to the increased levels of polyphenols, anthocyanins, and tannins in Tinto Cão berries, and polyphenols and tannins in Touriga Franca berries, respectively. CUPric Reducing Antioxidant Capacity (CUPRAC) and Ferric Reducing Antioxidant Power (FRAP) assays indicated an increase in the antioxidant potential of berries. With the exception of ascorbate peroxidase (APX), all the ROS pathway genes tested, i.e., iron-superoxide dismutase (Fe-SOD), copper-zinc-superoxide dismutase (Cu/Zn-SOD), catalase (CAT), glutathione reductase (GR), glutaredoxin (Grx), respiratory burst oxidase (Rboh), amine oxidase (AO), peroxidase (POD) and polyphenol oxidase (PPO), were found up-regulated in chitosan-treated berries. Results from the analyses of leaves, stems, and shoots revealed that chitosan not only induced the synthesis of phenolic compounds but also acted as a facilitator for the transfer of polyphenols from the leaves to the berries.

In vitro antimicrobial activity of root canal sealers and calcium hydroxide paste.

AIM: To evaluate the in vitro antimicrobial activity of different root canal sealers and calcium hydroxide (CH) paste. MATERIALS AND METHODS: The sample was composed of two sealers (Fill Canal(®) and Sealer 26(®)), one CH cement (Hydro C(®)), and a CH paste. The agar diffusion test was performed in Petri dishes inoculated with the following microorganisms: Streptococcus salivarius, Streptococcus oralis, Streptococcus mitis, Lactobacillus casei, Streptococcus mutans, Candida albicans, Candida krusei, and Candida tropicalis. The diameters of the zones of microbial growth inhibition were measured after 24 h. The tests were performed in triplicate. Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. RESULTS: Fill Canal(®) exhibited the largest mean zone of microbial growth inhibition against the Candida species and differed significantly from the other groups (P < 0.001). When inhibition was observed against S. mitis and S. oralis, the CH paste presented a larger mean zone of microbial growth inhibition than those of the other materials (P < 0.05). Regarding the inhibition of S. mutans, a statistically significant difference was observed only between the CH paste and Hydro C(®) (P < 0.05); the paste produced the largest mean zone of microbial growth inhibition against this microorganism. Regarding the inhibition of S. salivarius, Fill Canal(®) presented smaller mean zone of microbial growth inhibition than Sealer 26(®) and CH paste (P < 0.05). CONCLUSION: All the materials presented zones of microbial growth inhibition against all the test bacteria. Fill Canal(®) presented the largest mean zone of inhibition against the Candida species. For the Streptococcus cultures, none of the sealers presented inhibition superior to that of the CH paste.