Functional assessment of AtPAP17; encoding a purple acid phosphatase involved in phosphate metabolism in Arabidopsis thaliana.

PURPOSE: Purple acid phosphatases (PAPs) includ the largest classes of non-specific plant acid phosphatases. Most characterized PAPs were found to play physiological functions in phosphorus metabolism. In this study, we investigated the function of AtPAP17 gene encoding an important purple acid phosphatase in Arabidopsis thaliana. METHODS: The full-length cDNA sequence of AtPAP17 gene under the control of CaMV-35S promoter was transferred to the A. thaliana WT plant. The generated homozygote AtPAP17-overexpressed plants were compared by the types of analyses with corresponding homozygote atpap17-mutant plant and WT in both + P (1.2 mM) and - P (0 mM) conditions. RESULTS: In the + P condition, the highest and the lowest amount of Pi was observed in AtPAP17-overexpressed plants and atpap17-mutant plants by 111% increase and 38% decrease compared with the WT plants, respectively. Furthermore, under the same condition, APase activity of AtPAP17-overexpressed plants increased by 24% compared to the WT. Inversely, atpap17-mutant plant represented a 71% fall compared to WT plants. The comparison of fresh weight and dry weight in the studied plants showed that the highest and the lowest amount of absorbed water belonged to OE plants (with 38 and 12 mg plant-1) and Mu plants (with 22 and 7 mg plant-1) in + P and - P conditions, respectively. CONCLUSION: The lack of AtPAP17 gene in the A. thaliana genome led to a remarkable reduction in the development of root biomass. Thus, AtPAP17 could have an important role in the root but not shoot developmental and structural programming. Consequently, this function enables them to absorb more water and eventually associated with more phosphate absorption.

Evaluation of the Effectiveness of Herbal Components Based on Their Regulatory Signature on Carcinogenic Cancer Cells.

Predicting cancer cells' response to a plant-derived agent is critical for the drug discovery process. Recently transcriptomes advancements have provided an opportunity to identify regulatory signatures to predict drug activity. Here in this study, a combination of meta-analysis and machine learning models have been used to determine regulatory signatures focusing on differentially expressed transcription factors (TFs) of herbal components on cancer cells. In order to increase the size of the dataset, six datasets were combined in a meta-analysis from studies that had evaluated the gene expression in cancer cell lines before and after herbal extract treatments. Then, categorical feature analysis based on the machine learning methods was applied to examine transcription factors in order to find the best signature/pattern capable of discriminating between control and treated groups. It was found that this integrative approach could recognize the combination of TFs as predictive biomarkers. It was observed that the random forest (RF) model produced the best combination rules, including AIP/TFE3/VGLL4/ID1 and AIP/ZNF7/DXO with the highest modulating capacity. As the RF algorithm combines the output of many trees to set up an ultimate model, its predictive rules are more accurate and reproducible than other trees. The discovered regulatory signature suggests an effective procedure to figure out the efficacy of investigational herbal compounds on particular cells in the drug discovery process.

Toward more specific inhibitor for Solanum tuberosum polyphenol oxidase through a structural insight into its activities and inhibition.

To prevent enzymatic browning, applying a polyphenol oxidase (PPO) inhibitor is more desirable, especially when the freshness of the product matters. Most of the inhibition studies were done on mushroom tyrosinase (MT) while the literature indicates that MT and PPO of Solanum tuberosum (PPOsol ) respond differently to the same modulator despite their similar active sites. This research was conducted to deepen our knowledge about PPOsol and introduce a more specific inhibitor for this enzyme to be used in controlling the enzymatic browning of potatoes. A modified procedure was developed for PPOsol purification. The enzyme was subjected to some essential physicochemical and kinetics studies. In parallel to the comparable physicochemical properties, homology modeling revealed high structural similarity between Solanum lycopersicum PPO (PPOsly ) and PPOsol except for their active site pockets. Accordingly, PPOsol showed 5.1- and 34-fold higher affinity toward chlorogenic acid compared with two PPOsly isozymes. Alike PPOsly , PPOsol showed monophenolase activity but it was inactive toward L-tyrosine and p-coumaric acid. Based on structural criteria, phthalic acid, cinnamic acid, ferulic acid, and vanillin were selected and thoroughly examined for inhibition of the catecholase activity of PPOsol . Although all these substances inhibited PPOsol in mixed-inhibition mode, the results were strongly in favor of vanillin with IC50 < 1.37 mM and Ki < 1.2 mM. PRACTICAL APPLICATIONS: There are subtle structural differences in the active site pockets of polyphenol oxidase (PPOs) of various fruits, vegetables, and crops. Consequently, to introduce an efficient inhibitor for hindering enzymatic browning of crop products, it is essential to have detailed knowledge about the structure and activity of its PPO as the main player of this undesirable phenomenon. Results of this study not only shed light on the physicochemical properties of PPOsol but can also be used in making various formulations for safe controlling enzymatic browning of potatoes, especially fresh-cut and minimally processed products, and similar crops products during postharvest and the processes of products preparations.

Production of phenolic acids in hairy root cultures of medicinal plant Mentha spicata L. in response to elicitors.

In this study, hairy root induction in leaf and stem explants of Mentha spicata using various Agrobacterium rhizogenes strains was established for the first time. Although inoculation of explants by immersion method resulted in tissue necrosis, direct injection of explants by all examined strains (A13,R318,A4,GMI 9534 and ATCC15834) was effective. All different parts of the stem were susceptible to A. rhizogenes infection. However, the middle and lower internodes showed a higher rate of transformation. Among the different strains, the strain A13 exhibited the highest infection efficiency (almost 75% of the explants). A13 and R318-infected hairy roots showed the highest biomass production (close to 60 mg/flask), while infection with GMI 9534 produced the highest content of phenolic acids. Finally, the effect of phytohormone elicitation on hairy root growth and phenolic acid biosynthesis was investigated. A substantial increase in root growth and phenolic acids accumulation was obtained followed by 0.3 mg L-1 IBA and 100 µM MeJA treatment, respectively.