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Helinä Hartikainen

Bio: Helinä Hartikainen is an academic researcher from University of Helsinki. The author has contributed to research in topics: Glutathione peroxidase & Superoxide dismutase. The author has an hindex of 5, co-authored 5 publications receiving 1367 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, a pot experiment was carried out with lettuce (Lactuca sativa) cultivated with increasing amounts of H2SeO4, and the yields harvested 7 or 14 weeks after sowing revealed that a low Se dosage (0.1 mg kg−1 soil) stimulated the growth of senescing seedlings (dry weight yield by 14%) despite a decreased chlorophyll concentration.
Abstract: In human and animal cells, Se plays an essential role in antioxidation and exerts an antiaging function but it is toxic at high dietary intake. To increase its intake in forage and foodstuffs, Se fertilization is adopted in some countries where soils are low in bioavailable Se, even though higher plants are regarded not to require Se. To test its ability to counteract senescence-related oxidative stress in higher plants, a pot experiment was carried out with lettuce (Lactuca sativa) cultivated with increasing amounts of H2SeO4. The yields harvested 7 or 14 weeks after sowing revealed that a low Se dosage (0.1 mg kg−1 soil) stimulated the growth of senescing seedlings (dry weight yield by 14%) despite a decreased chlorophyll concentration. The growth-promoting function was related to diminished lipid peroxidation. In young and senescing plants, the antioxidative effect of Se was associated with the increased activity of glutathione peroxidase (GSH-Px). In the senescing plants, the added Se strengthened the antioxidative capacity also by preventing the reduction of tocopherol concentration and by enhancing superoxide dismutase (SOD) activity. When no Se was added, tocopherols and SOD activity diminished during plant senescence. The higher Se dosage (1.0 mg kg−1 soil) was toxic and reduced the yield of young plants. In the senescing plants, it diminished the dry weight yield but not the fresh weight yield.

501 citations

Journal ArticleDOI
TL;DR: In this paper, the toxicity of Se can be attributed to metabolic disturbances, in addition to its pro-oxidative effects, which can be explained by the changes in the total chlorophyll concentration.
Abstract: Selenium is an essential element for antioxidation reactions in human and animals. In order to study its biological role in higher plants, ryegrass (Lolium perenne) was cultivated in a soil without Se or amended with increasing dosages of H2SeO4 (0.1, 1.0, 10.0 and 30.0 mg Se kg−1). Ryegrass was harvested twice and the yields were analyzed for antioxidative systems and growth parameters. Selenium exerted dual effects: At low concentrations it acted as an antioxidant, inhibiting lipid peroxidation, whereas at higher concentrations, it was a pro-oxidant, enhancing the accumulation of lipid peroxidation products. The antioxidative effect was associated with an increase in glutathione peroxidase (GSH-Px) activity, but not with superoxide dismutase (SOD) and αα-tocopherol, which was the only tocopherol detected. In the second yield, the diminished lipid peroxidation due to a proper Se addition coincided with promoted plant growth. The oxidative stress found at the Se addition level ≥ 10 mg kg−1 resulted in drastic yield losses. This result indicates that the toxicity of Se can be attributed, in addition to metabolic disturbances, to its pro-oxidative effects. Neither the growth-promoting nor the toxic effect of Se could be explained by the changes in the total chlorophyll concentration.

492 citations

Journal ArticleDOI
TL;DR: The presence of Se in medium prevented changes in the DNA methylation pattern triggered in rape seedlings by high Cd concentrations, and removal of Cd from metabolically active cellular sites and reduction of oxygen radicals were considered.

244 citations

Journal ArticleDOI
TL;DR: The results suggest that Se is an antioxidant or it activates protective mechanisms, which can alleviate oxidative stress in the chloroplasts, and improve the recovery of chlorophyll content following light stress.

209 citations

Journal ArticleDOI
TL;DR: It is concluded that the agronomic biofortification of Brassica species can improve the nutritive quality of the protein rich meal fraction as it contains significant amount of SeMet.
Abstract: Selenium (Se) is an essential micronutrient and is circulated to the food chain through crops. Brassica species are efficient in Se accumulation and thus, good species for Se biofortification purposes. The residual fraction obtained after oil processing of Brassica seeds, the meal, is an important protein source in animal diets and used in feed concentrates. The accumulation of soil or foliar applied Se in the seeds and meal of Brassica napus and B. rapa as well as its effects on growth and yield formation was studied in two field experiments. Also, a HPLC-ICP-MS based method for the identification and quantification of Se species in Brassica seeds and meal was developed. Selenium application did not affect the yield or oil content. High accumulation of Se in the seeds and meal (1.92–1.96 μg Se g−1) was detected. Biotransformation of inorganic Se was evaluated by using HPLC-ICP-MS previous enzymatic hydrolysis for species extraction. The Se speciation studies showed that up to 85% of the total Se was SeMet whereas other Se-species were not detected. We conclude that the agronomic biofortification of Brassica species can improve the nutritive quality of the protein rich meal fraction as it contains significant amount of SeMet.

76 citations


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Book
01 Mar 2007
TL;DR: Trace Elements of the Human Environment: Biogeochemistry of Trace Elements and Trace Elements of Group 1 (Previously Group Ia).
Abstract: Biogeochemistry of the Human Environment.- The Biosphere.- Soils.- Waters.- Air.- Plants.- Humans.- Biogeochemistry of Trace Elements.- Trace Elements of Group 1 (Previously Group Ia).- Trace Elements of Group 2 (Previously Group IIa).- Trace Elements of Group 3 (Previously Group IIIb).- Trace Elements of Group 4 (Previously Group IVb).- Trace Elements of Group 5 (Previously Group Vb).- Trace Elements of Group 6 (Previously Group VIb).- Trace Elements of Group 7 (Previously Group VIIb).- Trace Elements of Group 8 (Previously Part of Group VIII).- Trace Elements of Group 9 (Previously Part of Group VIII).- Trace Elements of Group 10 (Previously Part of Group VIII).- Trace Elements of Group 11 (Previously Group Ib).- Trace Elements of Group 12 (Previously Group IIb).- Trace Elements of Group 13 (Previously Group IIIa).- Trace Elements of Group 14 (Previously Group IVa).- Trace Elements of Group 15 (Previously Group Va).- Trace Elements of Group 16 (Previously Group VIa).- Trace Elements of Group 17 (Previously Group VIIa).

1,700 citations

Journal ArticleDOI
TL;DR: In this paper, the authors review aspects of soil science, plant physiology and genetics underpinning crop bio-fortification strategies, as well as agronomic and genetic approaches currently taken to biofortify food crops with the mineral elements most commonly lacking in human diets: iron (Fe), zinc (Zn), copper (Cu), calcium (Ca), magnesium (Mg), iodine (I) and selenium (Se).
Abstract: Summary The diets of over two-thirds of the world's population lack one or more essential mineral elements. This can be remedied through dietary diversification, mineral supplementation, food fortification, or increasing the concentrations and/or bioavailability of mineral elements in produce (biofortification). This article reviews aspects of soil science, plant physiology and genetics underpinning crop biofortification strategies, as well as agronomic and genetic approaches currently taken to biofortify food crops with the mineral elements most commonly lacking in human diets: iron (Fe), zinc (Zn), copper (Cu), calcium (Ca), magnesium (Mg), iodine (I) and selenium (Se). Two complementary approaches have been successfully adopted to increase the concentrations of bioavailable mineral elements in food crops. First, agronomic approaches optimizing the application of mineral fertilizers and/or improving the solubilization and mobilization of mineral elements in the soil have been implemented. Secondly, crops have been developed with: increased abilities to acquire mineral elements and accumulate them in edible tissues; increased concentrations of ‘promoter’ substances, such as ascorbate, β-carotene and cysteine-rich polypeptides which stimulate the absorption of essential mineral elements by the gut; and reduced concentrations of ‘antinutrients’, such as oxalate, polyphenolics or phytate, which interfere with their absorption. These approaches are addressing mineral malnutrition in humans globally.

1,677 citations

Journal ArticleDOI
TL;DR: This review is to assess the mode of action and role of antioxidants in protecting plants from stress caused by the presence of heavy metals in the environment.
Abstract: The contamination of soils and water with metals has created a major environmental problem, leading to considerable losses in plant productivity and hazardous health effects. Exposure to toxic metals can intensify the production of reactive oxygen species (ROS), which are continuously produced in both unstressed and stressed plants cells. Some of the ROS species are highly toxic and must be detoxified by cellular stress responses, if the plant is to survive and grow. The aim of this review is to assess the mode of action and role of antioxidants in protecting plants from stress caused by the presence of heavy metals in the environment.

1,065 citations

Journal ArticleDOI
TL;DR: This review summarizes various tolerance strategies of plants under heavy metal toxicity covering the role of metabolites (metabolomics), trace elements (ionomics), transcription factors (transcriptomics), various stress-inducible proteins (proteomics) as well as therole of plant hormones.
Abstract: Heavy metal contamination of soil and water causing toxicity/stress has become one important constraint to crop productivity and quality. This situation has further worsened by the increasing population growth and inherent food demand. It have been reported in several studies that counterbalancing toxicity, due to heavy metal requires complex mechanisms at molecular, biochemical, physiological, cellular, tissue and whole plant level, which might manifest in terms of improved crop productivity. Recent advances in various disciplines of biological sciences such as metabolomics, transcriptomics, proteomics etc. have assisted in the characterization of metabolites, transcription factors, stress-inducible proteins involved in heavy metal tolerance, which in turn can be utilized for generating heavy metal tolerant crops. This review summarizes various tolerance strategies of plants under heavy metal toxicity, covering the role of metabolites (metabolomics), trace elements (ionomics), transcription factors (transcriptomics), various stress-inducible proteins (proteomics) as well as the role of plant hormones. We also provide a glance at strategies adopted by metal accumulating plants also known as “metallophytes”.

820 citations

Journal ArticleDOI
TL;DR: The aim of this review is to integrate a recent understanding of physiological and biochemical mechanisms of HM-induced plant stress response and tolerance based on the findings of current plant molecular biology research.
Abstract: Heavy metal (HM) toxicity is one of the major abiotic stresses leading to hazardous effects in plants. A common consequence of HM toxicity is the excessive accumulation of reactive oxygen species (ROS) and methylglyoxal (MG), both of which can cause peroxidation of lipids, oxidation of protein, inactivation of enzymes, DNA damage and/or interact with other vital constituents of plant cells. Higher plants have evolved a sophisticated antioxidant defense system and a glyoxalase system to scavenge ROS and MG. In addition, HMs that enter the cell may be sequestered by amino acids, organic acids, glutathione (GSH), or by specific metal-binding ligands. Being a central molecule of both the antioxidant defense system and the glyoxalase system, GSH is involved in both direct and indirect control of ROS and MG and their reaction products in plant cells, thus protecting the plant from HM-induced oxidative damage. Recent plant molecular studies have shown that GSH by itself and its metabolizing enzymes—notably glutathione S-transferase, glutathione peroxidase, dehydroascorbate reductase, glutathione reductase, glyoxalase I and glyoxalase II—act additively and coordinately for efficient protection against ROS- and MG-induced damage in addition to detoxification, complexation, chelation and compartmentation of HMs. The aim of this review is to integrate a recent understanding of physiological and biochemical mechanisms of HM-induced plant stress response and tolerance based on the findings of current plant molecular biology research.

812 citations