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Medicinal plants have been used for treatment of many diseases since the ancient times with traditional knowledge being transferred from generation to generation. However, in recent years, many natural habitats have been contaminated due to increased anthropogenic activities. Plants which are exposed to heavy metal toxicity may experience several serious problems. Furthermore, the inclusion of these plants into the food chain poses a threat to human health as well. Additionally, presence of heavy metals directly effect mineral nutrition and consequently the food quality. The aim of this study herewith is to determine the heavy metal content and mineral nutrient status of some medicinal plants to have insight on their health repercussions on plants and humans. The concentrations of Al, B, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb and Zn in commonly used parts (root, rhizome, seed, resin, gall, fruit) especially for remedial purposes of 17 medicinal plants collected from Turkey were analyzed by ICP-OES. The measured values for concentrations from lowest to highest were (in mg kg-1) 30.983-368.877 for Al, 13.845-186.015 for B, 1335.699-11213.951 for Ca, 0.016-0.653 for Cd, 0.379-30.708 for Cr, 23.838-90.444 for Cu, 78.960-1228.845 for Fe, 1035.948-6393.491 for K, 83.193-2252.031 for Mg, 12.111-362.570 for Mn, 278.464-1968.775 for Na, 1.945-35.732 for Ni, 0.796-17.162 for Pb and 166.910-395.252 for Zn. Overall, heavy metal concentrations in medicinal plants collected nearby industrial regions, mining and farming sites, were found to be in slightly higher levels. This shows us that it is of crucial importance that the areas where medicinal plants are collected are clean especially by means of heavy metals for the reason that these plants can cause more harm than the benefits they may provide if they are contaminated.

Ozyigit, Ibrahim Ilker/0000-0002-0825-5951 WOS: 000481746800001 Although stresses induce generation of reactive oxygen species (ROS), which are highly reactive and toxic, and cause severe damage to cellular components; plants have very efficient enzymatic ROS-scavenging mechanisms. Despite the substantial knowledge produced about these enzymes, we still have limited knowledge regarding their expression patterns in relation to the stress type, duration and strength. Thus, taking advantage of microarray data, this work evaluated the abiotic stresses (salt, cold, heat and light) induced regulation of six antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione peroxidase (GPX), monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR), in 10 natural Arabidopsis ecotypes. The expression profiles of 36 genes encoding six enzymatic antioxidants including CSD1-3, FSD1-3, MSD1-2, CAT1-3, APX1-6, APXT, APXS, GPX1-8, MDAR1-5 and DHAR1-4 were investigated. In particular, FSD1, FSD2, CSD1 and CSD2 genes coding for SOD; CAT2 and CAT3 for CAT; APX3-6, APXT and APXS for APX; GPX1, GPX2, GPX5, GPX6 and GPX7 for GPX; MDAR2-4 for MDHAR; and DHAR1 and DHAR3 for DHAR families appeared to be more differentially expressed under given stress conditions. Primarily, high light as well as salt and cold stresses considerably up-regulated the gene expression, whereas cold stress significantly led to the down-regulation of genes. The overall expression pattern of ecotypes suggested that the studied Arabidopsis genotypes had different stress tolerance.

Boron (B) is an essential plant micronutrient but studies regarding its transport are still limited to a few plants. This work identified two major B transport sequences in plants, NIP5;1 boric acid channel protein and BOR1 transporter. 80 BOR1 and 34 NIP5;1 homologs were identified in 18 different plant genomes. BOR1 homologs had a HCO3-transporter domain, 649-737 amino-acid residues with mainly basic nature, putative 8-11 transmembrane domains (TMDs) and 11-13 exons. NIP5;1 homologs had a MIP family domain, 294-311 amino-acid residues with basic nature, 5-6 putative TMDs and 3-5 exons. Tyrosine-based motif, acidic di-leucine motif and lysine residue, reported for polarity, vacuolar sorting and B-dependent degradation, were identified in BOR1 homologs. Two NPA motifs and an ar/R selectivity filter with AIGR residues, reportedly essential in B transport, were also found in NIP5;1 homologs. Two NPA motifs in AtNIP5;1 and OsNIP3;1 homologs were NPS and NPV, whereas in sequences homologous to AtNIP6;1 were NPA/V. Besides, ar/R selectivity filters were identified with A(N/S/T)IGR residues in NIP5;1 and NIP3;1 homologs. The BOR1 and NIP5;1 model structures were mainly conserved. Under different perturbations, Arabidopsis thaliana NIP5;1 and NIP6;1 genes demonstrated similar expression patterns although they act in different tissues, suggesting a common regulatory mechanism, whereas BOR1 showed a different expression pattern. BOR1 was substantially expressed in primary root, radicle and flower; NIP5;1 in primary root and roots, and NIP6;1 in petiole. NIP5;1, 6;1 and BOR1 expression in other plant organs implied their involvement in different pathways in addition to B uptake and its mobilization. WOS:000538924900001 2-s2.0-85087093473

Ozyigit, Ibrahim Ilker/0000-0002-0825-5951 WOS: 000475893100001 Plants employ various defence strategies to ameliorate the effects of heavy metal exposures, leading to re-establishment of metal homeostasis. One of the strategies includes the biosynthesis of main heavy metal detoxifying peptides phytochelatins (PCs) by phytochelatin synthase (PCS). In the present study, 14 PCS homologues were identified in the genomes of 10 selected plants. The size of these PCSs was 452-545 amino acid residues, with characteristic phytochelatin and phytochelatin_C domains. The N-terminal site of the proteins is highly conserved, whereas the C-terminal site is less conserved. Further, the present study also identified fully conserved Cys residues involved in heavy metal binding reported earlier. In addition, other preserved cysteines, with minor substitutions Cys(C)-> Ser(S) or Tyr(Y) or Trp(W), were also identified in the PCS sequences that might be associated with metal binding. The reported catalytic triad residues from Arabidopsis, Cys56, His162 and Asp180, are all conserved at the respective sites of PCSs. A clear monocot/dicot separation was revealed by phylogenetic analysis and was further corroborated by the exon-intron organisations of the PCS genes. Moreover, gene ontology terms, co-expression network, cis-regulatory motif and miRNA analyses indicated that the complex as well as dynamic regulation of PCSs has significant involvement in different metabolic pathways associated with signalling, defence, stress and phytohormone, in addition to metal detoxification. Moreover, variations in protein structure are suggested to confer the functional divergence in PCS proteins.

The use of plants in treatments has been as old as humanity and it has preserved its popularity for centuries til now because of their availability, affordability and safeness. However, despite their widespread use, safety and quality issues have been major concerns in the world due to industrial- and anthropogenic-based heavy metal contamination risks. Thus, this study was attempted to analyze the heavy metal levels and mineral nutrient status of widely used medicinal plants in Turkey to have insights about their health implications on humans. The plant concentrations of B, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb and Zn were analyzed by ICP-OES in the leaves of 44 medical plants purchased from herbal markets of three different districts of Istanbul/Turkey. The measured lowest to highest concentrations were 0.065-79.749 mg kg(-1) B, 921.802-12,854.410 mg kg(-1) Ca, 0.020-0.558 mg kg(-1) Cd, 0.015-4.978 mg kg(-1) Cr, 0.042-8.489 mg kg(-1) Cu, 34.356-858.446 mg kg(-1) Fe, 791.323-15,569.349 mg kg(-1) K, 102.236-2837.836 mg kg(-1) Mg, 4.915-91.519 mg kg(-1) Mn, 10.224-3213.703 mg kg(-1) Na, 0.001-5.589 mg kg(-1) Ni, 0.003-3.636 mg kg(-1) Pb and 2.601-36.102 mg kg(-1) Zn. Those levels in plants were in acceptable limits though some elements in some plants have high limits which were not harmful. Variations (above acceptable limits) in element concentrations also indicated that these plants could be contaminated with other metals and that genetic variations may influence accumulation of these elements at different contents. Overall, analyzed medicinal plants are expected not to pose any serious threat to human health. Research Foundation of Marmara University (BAPKO)Marmara University [FEN-C-YLP-130612-0230] We would like to express our special gratitude to Dr. Mehmet Emin Uras and Dr. Recep Vatansever for their assistance from Marmara University, Department of Biology. Also, we are thankful to Assoc. Prof. Dr. Birsen Eygi Erdogan from Marmara University, Department of Statistics for the statistical analyses. This study was supported in part by the Research Foundation of Marmara University (BAPKO), Project No. FEN-C-YLP-130612-0230.