Andrzej Bajguz - Academia.edu (original) (raw)

Papers by Andrzej Bajguz

The effect of exogenously applied natural [indole-3-acetic acid (IAA), phenylacetic acid (PAA), i... more The effect of exogenously applied natural [indole-3-acetic acid (IAA), phenylacetic acid (PAA), indole-3-butyric acid (IBA)] and synthetic [1-naphthaleneacetic acid (NAA)] auxins on the growth and metabolism of green microalga Chlorella vulgaris was examined. Exogenous auxins acted in a concentration-dependent manner on algal growth. Phytohormones at concentration of 100 lM inhibited algal growth expressed as the number of cells. IAA and IBA displayed the highest biological activity at 0.1 lM, whereas PAA and NAA were characterized by the greatest stimulatory effect on the number of cells at 1 lM. Treatment with IAA and IBA at 0.1 lM or NAA and PAA at 1 lM increased the concentration of photosynthetic pigments, monosaccharides and soluble proteins in C. vulgaris. Moreover, all auxins stimulated enzymatic (ascorbate peroxidase, catalase, superoxide dismutase) and non-enzymatic antioxidant (ascorbate, glutathione) systems in C. vulgaris, and therefore, suppressed lipid peroxidation and hydrogen peroxide accumulation. The data supports the hypothesis that auxins play a central role in the regulation of C. vulgaris growth and metabolism and the components of cellular redox systems that are thought to have a prominent role in the regulation of auxindependent processes.

Phytohormones: A Window to Metabolism, Signaling and Biotechnological Applications, 2014

ABSTRACT Brassinosteroids (BRs) are steroidal hormones essential for plant growth and development... more ABSTRACT Brassinosteroids (BRs) are steroidal hormones essential for plant growth and development. They are implicated in plant responses to abiotic environmental stresses such as low and high temperature, drought, salt, infection, pesticides, and heavy metals. BR-regulated stress response is a result of a complex sequence of biochemical reactions such as activation or suppression of key enzymatic reactions, induction of protein synthesis, and the production of various chemical defence compounds. However, the molecular mechanism of BR-induced plant abiotic stress tolerance remains poorly understood. The BR signalling is initiated by a ligand-induced kinase activation followed by receptor oligomerisation. The signal transduction in the cell is mediated through phosphorylation and transcription factors which directly bind to promoters of BR-responsive genes to regulate their expression. BRs that are biosynthesised using sterols as precursors are structurally similar to the cholesterol-derived, human steroid hormones and insect moulting hormones. The biosynthetic pathway of BRs is divided into multiple subunits. Depending on C-22 hydroxylation at campesterol, the BR pathway is further divided into the early and late C-22 oxidation pathways. Similarly, the C-6 position can be oxidised at campestanol or later at 6-deoxocathasterone stage, and thus these are called the early and late C-6 oxidation pathways, respectively. The pathways of BR biosynthesis in plants are well studied. Nevertheless, in order to understand properly the role of BRs during plant development under stress conditions, it seems essential to summarise the experimental data, focusing on the biosynthesis and signal transduction. © Springer Science+Business Media New York 2014. All rights are reserved.

Studies in Natural Products Chemistry, 2015

Studies in Natural Products Chemistry, 2013

Phytohormones and Abiotic Stress Tolerance in Plants, 2012

ABSTRACT Brassinosteroids (BRs) are a class of plant polyhydroxysteroids that have been recognize... more ABSTRACT Brassinosteroids (BRs) are a class of plant polyhydroxysteroids that have been recognized as a kind of phytohormones and play essential roles in plant development. BRs occur at low concentrations in lower and higher plants. Natural 70 BRs identified so far have a common 5α-cholestan skeleton, and their structural variations come from the kind and orientation of oxygenated functions in rings A and B. As regards the B-ring oxidation, BRs are divided into the following types: 7-oxalactone, 6-oxo, 6-deoxo and 6-hydroxy. These steroids can be also classified as C27, C28 or C29 BRs depending on the alkyl substitution on the C-24 in the side chain. In addition to free BRs, sugar and fatty acid conjugates have been also identified in plants. Plant growth and developmental processes as well as environmental responses require the action and cross talk of BRs and reactive oxygen species (ROS). ROS can partake in signalling, although these events will be modulated by the complement of antioxidants in, or even around, the cell. ROS can interact with other signal molecules, including BRs in regulation of these physiological responses. BRs can modify the synthesis of antioxidants and the activity of basic antioxidant enzymes, and some of these enzymes are also implicated in catabolism of plant hormone. However, it is still unclear whether endogenous BRs directly or indirectly modulate the responses of plants to oxidative stress. The recent progress made in understanding the response of BRs in plants under oxidative stress.

Environmental Science and Pollution Research, 2015

Acta Societatis Botanicorum Poloniae, 1994

Plant Physiology and Biochemistry, 2014

Interaction between brassinosteroids (BRs) (brassinolide, BL; 28homobrassinolide, castasterone, C... more Interaction between brassinosteroids (BRs) (brassinolide, BL; 28homobrassinolide, castasterone, CS; and adenine-(trans-zeatin, tZ; kinetin, Kin) as well as phenylurea-type (1,3-diphenylurea, DPU) cytokinins (CKs) in the regulation of cell number, phytohormone level and the content of chlorophyll, monosaccharide and protein in unicellular green alga Chlorella vulgaris (Trebouxiophyceae) were examined. Chlorella vulgaris exhibited sensitivity to CKs in the following order of their stimulating properties: 10 nM tZ > 100 nM Kin >1 mM DPU. Exogenously applied BRs possessed the highest biological activity in algal cells at concentration of 10 nM. Among the BRs, BL was characterized by the highest activity, while 28-homoCS -by the lowest. The considerable increase in the level of all endogenous BRs by 27e46% was observed in C. vulgaris culture treated with exogenous 10 nM tZ. It can be speculated that CKs may stimulate BR activity in C. vulgaris by inducing the accumulation of endogenous BRs. CKs interacted synergistically with BRs increasing the number of cells and endogenous accumulation of proteins, chlorophylls and monosaccharides in C. vulgaris. The highest stimulation of algal growth and the contents of analyzed biochemical parameters were observed for BL applied in combination with tZ, whereas the lowest in the culture treated with both 28-homoCS and DPU. However, regardless of the applied mixture of BRs with CKs, the considerable increase in cell number and the metabolite accumulation was found above the level obtained in cultures treated with any single phytohormone in unicellular green alga C. vulgaris.

Plant Physiology and Biochemistry, 2013

The relationships between brassinosteroids (BRs) (brassinolide, BL; 24-epiBL; 28-homoBL; castaste... more The relationships between brassinosteroids (BRs) (brassinolide, BL; 24-epiBL; 28-homoBL; castasterone, CS; 24-epiCS; 28-homoCS) and auxins (indole-3-acetic acid, IAA; indole-3-butyric acid, IBA; indole-3-propionic acid, IPA) in the regulation of cell number, phytohormone level and metabolism in green alga Chlorella vulgaris were investigated. Exogenously applied auxins had the highest biological activity in algal cells at 50 μM. Among the auxins, IAA was characterized by the highest activity, while IBA - by the lowest. BRs at 0.01 μM were characterized by the highest biological activity in relation to auxin-treated and untreated cultures of C. vulgaris. The application of 50 μM IAA stimulated the level of all detected endogenous BRs in C. vulgaris cells. The stimulatory effect of BRs in green algae was arranged in the following order: BL > 24-epiBL > 28-homoBL > CS > 24-epiCS > 28-homoCS. Auxins cooperated synergistically with BRs stimulating algal cell proliferation and endogenous accumulation of proteins, chlorophylls and monosaccharides in C. vulgaris. The highest stimulation of algal growth and the contents of analyzed biochemical parameters were observed for the mixture of BL with IAA, whereas the lowest in the culture treated with both 28-homoCS and IBA. However, regardless of the applied mixture of BRs with auxins, the considerable increase in cell number and the metabolite accumulation was found above the level obtained in cultures treated with any single phytohormone. Obtained results confirm that both groups of plant hormones cooperate synergistically in the control of growth and metabolism of unicellular green alga C. vulgaris.

Acta Societatis Botanicorum Poloniae, 2001

Brassinosteroids: A Class of Plant Hormone, 2010

Brassinosteroids (BRs) are a class of plant polyhydroxysteroids that have been recognized as a ne... more Brassinosteroids (BRs) are a class of plant polyhydroxysteroids that have been recognized as a new kind of phytohormones that play an essential role in plant development. BRs occur at low concentrations throughout the plant kingdom. They have been detected in all plant organs (pollen, anthers, seeds, leaves, stems, roots, flowers, and grains) and also in the insect and crown galls.

Acta Societatis Botanicorum Poloniae, 1997

Oceanological and Hydrobiological Studies, 2013

The ether and methanol extracts of Wolffia arrhiza (Lemnaceae) were analyzed using high resolutio... more The ether and methanol extracts of Wolffia arrhiza (Lemnaceae) were analyzed using high resolution capillary gas chromatography coupled with mass spectrometry (GC-MS). The ether extract contains 32 compounds, mostly lipids and sterols, among which β-sitosterol is most prevalent. This is the first evidence of β-sitosterol detection in W. arrhiza. The most representative group of polar compounds of the methanol fraction is formed by 18 free amino acids. In addition, in the methanol extract there are a number of other nitrogen containing compounds: nucleobase and nucleosides. The third significant group in the total ion current in the methanol extract is formed by glycerol and glycerides. At the same time, the content of free sugar is very low.

Journal of Plant Physiology, 2009

The brassinosteroids (BRs) occur ubiquitously in the plant kingdom. The occurrence of BRs has bee... more The brassinosteroids (BRs) occur ubiquitously in the plant kingdom. The occurrence of BRs has been demonstrated in almost every part of higher plants, such as pollen, flower buds, fruits, seeds, vascular cambium, leaves, shoots and roots. In this study, BRs were isolated and identified in the culture of wild-type Chlorella vulgaris. Seven BRs, including teasterone, typhasterol, 6-deoxoteasterone, 6-deoxotyphasterol, 6-deoxocastasterone, castasterone and brassinolide, were identified by GC-MS. All compounds belong to the BR biosynthetic pathway. The results suggest that early and late C6 oxidation pathways are operating in C. vulgaris. This study represents the first isolation of BRs from C. vulgaris cultures.

Journal of Plant Physiology, 2009

The present study was undertaken to test the influence of exogenously applied 10 nM brassinolide ... more The present study was undertaken to test the influence of exogenously applied 10 nM brassinolide (BL) on the abscisic acid (ABA) content in Chlorella vulgaris cultures subjected to short-term (3 h) heat stress (30-40 1C). We found that BL enhanced the ABA content with increase in temperature. In parallel, under these conditions treatment with BL resulted in growth levels very similar to those of control cell cultures (non-treated). BL had no significant effect on the content of chlorophyll or sugar in Chlorella vulgaris cells. Only a slight effect of BL on the protein content was observed. Under normal growth conditions (25 1C), BL showed a minor increase in the ABA content in Chlorella vulgaris cells. The present work also demonstrates that Chlorella vulgaris can synthesize ABA. This is the first evidence of ABA detection in Chlorella vulgaris cells.

Acta Societatis Botanicorum Poloniae, 2003

This study concerns on the influence of diamines (agmatine, putrescine) and polyamines (spermine,... more This study concerns on the influence of diamines (agmatine, putrescine) and polyamines (spermine, spermidine) upon the growth and the content of chlorophyll a and b, monosaccharides and proteins in the cells of alga Chlorella vulgaris Beijerinck (Chlorophyceae). In the experiments agmatine, putrescine, spermine and spermidine in the range of concentrations 10 -6 -10 -3 M were used. At the concentration 10 -3 M and the 1st day of cultivation, they have a toxic effect on growth of the algae. It was found that di-and polyamines used within the range of concentration 10 -6 -10 -4 M stimulate the growth and the contents of analysed biochemical parameters in the cells of C. vulgaris. The most stimulating influence on metabolism of the alga was demonstrated by spermidine and putrescine at concentration of 10 -4 M. Agmatine and spermine were characterised by a lower biological activity than spermidine and putrescine demonstrated the most stimulating influence.

Plant Physiology and Biochemistry, 2012

The present study was undertaken to test the influence of exogenously applied phytohormones: auxi... more The present study was undertaken to test the influence of exogenously applied phytohormones: auxins (IAA, IBA, NAA, PAA), cytokinins (BA, CPPU, DPU, 2iP, Kin, TDZ, Z), gibberellin (GA 3 ), jasmonic acid (JA) as well as polyamine -spermidine (Spd) upon the growth and metabolism of green microalga Chlorella vulgaris (Chlorophyceae) exposed to heavy metal (Cd, Cu, Pb) stress. The inhibitory effect of heavy metals on algal growth, metabolite accumulation and enzymatic as well as non-enzymatic antioxidant system was arranged in the following order: Cd > Pb > Cu. Exogenously applied phytohormones modify the phytotoxicity of heavy metals.

Phytochemistry, 2011

Phytohormones, including auxins, abscisic acid, brassinosteroids, cytokinins, ethylene, gibberell... more Phytohormones, including auxins, abscisic acid, brassinosteroids, cytokinins, ethylene, gibberellins, and jasmonates, are involved in all aspects of plant growth, and developmental processes as well as environmental responses. However, our understanding of hormonal homeostasis is far from complete. Phytohormone conjugation is considered as a part of the mechanism to control cellular levels of these compounds. Active phytohormones are changed into multiple forms by acylation, esterification or glycosylation, for example. It seems that conjugated compounds could serve as pool of inactive phytohormones that can be converted to active forms by de-conjugation reactions. Some conjugates are thought to be temporary storage forms, from which free active hormones can be released after hydrolysis. It is also believed that conjugation serves functions, such as irreversible inactivation, transport, compartmentalization, and protection against degradation. The nature of abscisic acid, brassinost...

Plant Physiology and Biochemistry, 2000

This study was conducted to investigate changes of nucleic acids and protein levels in response t... more This study was conducted to investigate changes of nucleic acids and protein levels in response to brassinosteroid (BR) effect in the green alga Chlorella vulgaris Beijerinck. BRs had the greatest effect on growth and metabolism of algae between 24 and 36 h after treatment in the range from 10 -12 to 10 -8 M. The highest growth of the content of nucleic acids and proteins was observed in the case of brassinolide (BL) at the concentration 10 -8 M in the 36th hour of cultivation. BL and its derivatives are biologically more active than castasterone (CS). The lowest stimulatory activity was shown by homoCS. The stimulatory effect of BRs in the algae was arranged in the following order: BL > 24-epiBL > homoBL > CS > 24-epiCS > homoCS. The relationship between the structure and the biological activity of BRs in stimulation of growth and changes in the content of DNA, RNA and proteins are discussed. © 2000 Éditions scientifiques et médicales Elsevier SAS Algae / brassinosteroids / Chlorella vulgaris / nucleic acids / phytohormones / proteins BL, brassinolide / BRs, brassinosteroids / CS, castasterone / 24-epiBL, 24-epibrassinolide / 24-epiCS, 24-epicastasterone / homoBL, homobrassinolide / homoCS, homocastasterone

The effect of exogenously applied natural [indole-3-acetic acid (IAA), phenylacetic acid (PAA), i... more The effect of exogenously applied natural [indole-3-acetic acid (IAA), phenylacetic acid (PAA), indole-3-butyric acid (IBA)] and synthetic [1-naphthaleneacetic acid (NAA)] auxins on the growth and metabolism of green microalga Chlorella vulgaris was examined. Exogenous auxins acted in a concentration-dependent manner on algal growth. Phytohormones at concentration of 100 lM inhibited algal growth expressed as the number of cells. IAA and IBA displayed the highest biological activity at 0.1 lM, whereas PAA and NAA were characterized by the greatest stimulatory effect on the number of cells at 1 lM. Treatment with IAA and IBA at 0.1 lM or NAA and PAA at 1 lM increased the concentration of photosynthetic pigments, monosaccharides and soluble proteins in C. vulgaris. Moreover, all auxins stimulated enzymatic (ascorbate peroxidase, catalase, superoxide dismutase) and non-enzymatic antioxidant (ascorbate, glutathione) systems in C. vulgaris, and therefore, suppressed lipid peroxidation and hydrogen peroxide accumulation. The data supports the hypothesis that auxins play a central role in the regulation of C. vulgaris growth and metabolism and the components of cellular redox systems that are thought to have a prominent role in the regulation of auxindependent processes.

Phytohormones: A Window to Metabolism, Signaling and Biotechnological Applications, 2014

ABSTRACT Brassinosteroids (BRs) are steroidal hormones essential for plant growth and development... more ABSTRACT Brassinosteroids (BRs) are steroidal hormones essential for plant growth and development. They are implicated in plant responses to abiotic environmental stresses such as low and high temperature, drought, salt, infection, pesticides, and heavy metals. BR-regulated stress response is a result of a complex sequence of biochemical reactions such as activation or suppression of key enzymatic reactions, induction of protein synthesis, and the production of various chemical defence compounds. However, the molecular mechanism of BR-induced plant abiotic stress tolerance remains poorly understood. The BR signalling is initiated by a ligand-induced kinase activation followed by receptor oligomerisation. The signal transduction in the cell is mediated through phosphorylation and transcription factors which directly bind to promoters of BR-responsive genes to regulate their expression. BRs that are biosynthesised using sterols as precursors are structurally similar to the cholesterol-derived, human steroid hormones and insect moulting hormones. The biosynthetic pathway of BRs is divided into multiple subunits. Depending on C-22 hydroxylation at campesterol, the BR pathway is further divided into the early and late C-22 oxidation pathways. Similarly, the C-6 position can be oxidised at campestanol or later at 6-deoxocathasterone stage, and thus these are called the early and late C-6 oxidation pathways, respectively. The pathways of BR biosynthesis in plants are well studied. Nevertheless, in order to understand properly the role of BRs during plant development under stress conditions, it seems essential to summarise the experimental data, focusing on the biosynthesis and signal transduction. © Springer Science+Business Media New York 2014. All rights are reserved.

Studies in Natural Products Chemistry, 2015

Studies in Natural Products Chemistry, 2013

Phytohormones and Abiotic Stress Tolerance in Plants, 2012

ABSTRACT Brassinosteroids (BRs) are a class of plant polyhydroxysteroids that have been recognize... more ABSTRACT Brassinosteroids (BRs) are a class of plant polyhydroxysteroids that have been recognized as a kind of phytohormones and play essential roles in plant development. BRs occur at low concentrations in lower and higher plants. Natural 70 BRs identified so far have a common 5α-cholestan skeleton, and their structural variations come from the kind and orientation of oxygenated functions in rings A and B. As regards the B-ring oxidation, BRs are divided into the following types: 7-oxalactone, 6-oxo, 6-deoxo and 6-hydroxy. These steroids can be also classified as C27, C28 or C29 BRs depending on the alkyl substitution on the C-24 in the side chain. In addition to free BRs, sugar and fatty acid conjugates have been also identified in plants. Plant growth and developmental processes as well as environmental responses require the action and cross talk of BRs and reactive oxygen species (ROS). ROS can partake in signalling, although these events will be modulated by the complement of antioxidants in, or even around, the cell. ROS can interact with other signal molecules, including BRs in regulation of these physiological responses. BRs can modify the synthesis of antioxidants and the activity of basic antioxidant enzymes, and some of these enzymes are also implicated in catabolism of plant hormone. However, it is still unclear whether endogenous BRs directly or indirectly modulate the responses of plants to oxidative stress. The recent progress made in understanding the response of BRs in plants under oxidative stress.

Environmental Science and Pollution Research, 2015

Acta Societatis Botanicorum Poloniae, 1994

Plant Physiology and Biochemistry, 2014

Interaction between brassinosteroids (BRs) (brassinolide, BL; 28homobrassinolide, castasterone, C... more Interaction between brassinosteroids (BRs) (brassinolide, BL; 28homobrassinolide, castasterone, CS; and adenine-(trans-zeatin, tZ; kinetin, Kin) as well as phenylurea-type (1,3-diphenylurea, DPU) cytokinins (CKs) in the regulation of cell number, phytohormone level and the content of chlorophyll, monosaccharide and protein in unicellular green alga Chlorella vulgaris (Trebouxiophyceae) were examined. Chlorella vulgaris exhibited sensitivity to CKs in the following order of their stimulating properties: 10 nM tZ > 100 nM Kin >1 mM DPU. Exogenously applied BRs possessed the highest biological activity in algal cells at concentration of 10 nM. Among the BRs, BL was characterized by the highest activity, while 28-homoCS -by the lowest. The considerable increase in the level of all endogenous BRs by 27e46% was observed in C. vulgaris culture treated with exogenous 10 nM tZ. It can be speculated that CKs may stimulate BR activity in C. vulgaris by inducing the accumulation of endogenous BRs. CKs interacted synergistically with BRs increasing the number of cells and endogenous accumulation of proteins, chlorophylls and monosaccharides in C. vulgaris. The highest stimulation of algal growth and the contents of analyzed biochemical parameters were observed for BL applied in combination with tZ, whereas the lowest in the culture treated with both 28-homoCS and DPU. However, regardless of the applied mixture of BRs with CKs, the considerable increase in cell number and the metabolite accumulation was found above the level obtained in cultures treated with any single phytohormone in unicellular green alga C. vulgaris.

Plant Physiology and Biochemistry, 2013

The relationships between brassinosteroids (BRs) (brassinolide, BL; 24-epiBL; 28-homoBL; castaste... more The relationships between brassinosteroids (BRs) (brassinolide, BL; 24-epiBL; 28-homoBL; castasterone, CS; 24-epiCS; 28-homoCS) and auxins (indole-3-acetic acid, IAA; indole-3-butyric acid, IBA; indole-3-propionic acid, IPA) in the regulation of cell number, phytohormone level and metabolism in green alga Chlorella vulgaris were investigated. Exogenously applied auxins had the highest biological activity in algal cells at 50 μM. Among the auxins, IAA was characterized by the highest activity, while IBA - by the lowest. BRs at 0.01 μM were characterized by the highest biological activity in relation to auxin-treated and untreated cultures of C. vulgaris. The application of 50 μM IAA stimulated the level of all detected endogenous BRs in C. vulgaris cells. The stimulatory effect of BRs in green algae was arranged in the following order: BL > 24-epiBL > 28-homoBL > CS > 24-epiCS > 28-homoCS. Auxins cooperated synergistically with BRs stimulating algal cell proliferation and endogenous accumulation of proteins, chlorophylls and monosaccharides in C. vulgaris. The highest stimulation of algal growth and the contents of analyzed biochemical parameters were observed for the mixture of BL with IAA, whereas the lowest in the culture treated with both 28-homoCS and IBA. However, regardless of the applied mixture of BRs with auxins, the considerable increase in cell number and the metabolite accumulation was found above the level obtained in cultures treated with any single phytohormone. Obtained results confirm that both groups of plant hormones cooperate synergistically in the control of growth and metabolism of unicellular green alga C. vulgaris.

Acta Societatis Botanicorum Poloniae, 2001

Brassinosteroids: A Class of Plant Hormone, 2010

Brassinosteroids (BRs) are a class of plant polyhydroxysteroids that have been recognized as a ne... more Brassinosteroids (BRs) are a class of plant polyhydroxysteroids that have been recognized as a new kind of phytohormones that play an essential role in plant development. BRs occur at low concentrations throughout the plant kingdom. They have been detected in all plant organs (pollen, anthers, seeds, leaves, stems, roots, flowers, and grains) and also in the insect and crown galls.

Acta Societatis Botanicorum Poloniae, 1997

Oceanological and Hydrobiological Studies, 2013

The ether and methanol extracts of Wolffia arrhiza (Lemnaceae) were analyzed using high resolutio... more The ether and methanol extracts of Wolffia arrhiza (Lemnaceae) were analyzed using high resolution capillary gas chromatography coupled with mass spectrometry (GC-MS). The ether extract contains 32 compounds, mostly lipids and sterols, among which β-sitosterol is most prevalent. This is the first evidence of β-sitosterol detection in W. arrhiza. The most representative group of polar compounds of the methanol fraction is formed by 18 free amino acids. In addition, in the methanol extract there are a number of other nitrogen containing compounds: nucleobase and nucleosides. The third significant group in the total ion current in the methanol extract is formed by glycerol and glycerides. At the same time, the content of free sugar is very low.

Journal of Plant Physiology, 2009

The brassinosteroids (BRs) occur ubiquitously in the plant kingdom. The occurrence of BRs has bee... more The brassinosteroids (BRs) occur ubiquitously in the plant kingdom. The occurrence of BRs has been demonstrated in almost every part of higher plants, such as pollen, flower buds, fruits, seeds, vascular cambium, leaves, shoots and roots. In this study, BRs were isolated and identified in the culture of wild-type Chlorella vulgaris. Seven BRs, including teasterone, typhasterol, 6-deoxoteasterone, 6-deoxotyphasterol, 6-deoxocastasterone, castasterone and brassinolide, were identified by GC-MS. All compounds belong to the BR biosynthetic pathway. The results suggest that early and late C6 oxidation pathways are operating in C. vulgaris. This study represents the first isolation of BRs from C. vulgaris cultures.

Journal of Plant Physiology, 2009

The present study was undertaken to test the influence of exogenously applied 10 nM brassinolide ... more The present study was undertaken to test the influence of exogenously applied 10 nM brassinolide (BL) on the abscisic acid (ABA) content in Chlorella vulgaris cultures subjected to short-term (3 h) heat stress (30-40 1C). We found that BL enhanced the ABA content with increase in temperature. In parallel, under these conditions treatment with BL resulted in growth levels very similar to those of control cell cultures (non-treated). BL had no significant effect on the content of chlorophyll or sugar in Chlorella vulgaris cells. Only a slight effect of BL on the protein content was observed. Under normal growth conditions (25 1C), BL showed a minor increase in the ABA content in Chlorella vulgaris cells. The present work also demonstrates that Chlorella vulgaris can synthesize ABA. This is the first evidence of ABA detection in Chlorella vulgaris cells.

Acta Societatis Botanicorum Poloniae, 2003

This study concerns on the influence of diamines (agmatine, putrescine) and polyamines (spermine,... more This study concerns on the influence of diamines (agmatine, putrescine) and polyamines (spermine, spermidine) upon the growth and the content of chlorophyll a and b, monosaccharides and proteins in the cells of alga Chlorella vulgaris Beijerinck (Chlorophyceae). In the experiments agmatine, putrescine, spermine and spermidine in the range of concentrations 10 -6 -10 -3 M were used. At the concentration 10 -3 M and the 1st day of cultivation, they have a toxic effect on growth of the algae. It was found that di-and polyamines used within the range of concentration 10 -6 -10 -4 M stimulate the growth and the contents of analysed biochemical parameters in the cells of C. vulgaris. The most stimulating influence on metabolism of the alga was demonstrated by spermidine and putrescine at concentration of 10 -4 M. Agmatine and spermine were characterised by a lower biological activity than spermidine and putrescine demonstrated the most stimulating influence.

Plant Physiology and Biochemistry, 2012

The present study was undertaken to test the influence of exogenously applied phytohormones: auxi... more The present study was undertaken to test the influence of exogenously applied phytohormones: auxins (IAA, IBA, NAA, PAA), cytokinins (BA, CPPU, DPU, 2iP, Kin, TDZ, Z), gibberellin (GA 3 ), jasmonic acid (JA) as well as polyamine -spermidine (Spd) upon the growth and metabolism of green microalga Chlorella vulgaris (Chlorophyceae) exposed to heavy metal (Cd, Cu, Pb) stress. The inhibitory effect of heavy metals on algal growth, metabolite accumulation and enzymatic as well as non-enzymatic antioxidant system was arranged in the following order: Cd > Pb > Cu. Exogenously applied phytohormones modify the phytotoxicity of heavy metals.

Phytochemistry, 2011

Phytohormones, including auxins, abscisic acid, brassinosteroids, cytokinins, ethylene, gibberell... more Phytohormones, including auxins, abscisic acid, brassinosteroids, cytokinins, ethylene, gibberellins, and jasmonates, are involved in all aspects of plant growth, and developmental processes as well as environmental responses. However, our understanding of hormonal homeostasis is far from complete. Phytohormone conjugation is considered as a part of the mechanism to control cellular levels of these compounds. Active phytohormones are changed into multiple forms by acylation, esterification or glycosylation, for example. It seems that conjugated compounds could serve as pool of inactive phytohormones that can be converted to active forms by de-conjugation reactions. Some conjugates are thought to be temporary storage forms, from which free active hormones can be released after hydrolysis. It is also believed that conjugation serves functions, such as irreversible inactivation, transport, compartmentalization, and protection against degradation. The nature of abscisic acid, brassinost...

Plant Physiology and Biochemistry, 2000

This study was conducted to investigate changes of nucleic acids and protein levels in response t... more This study was conducted to investigate changes of nucleic acids and protein levels in response to brassinosteroid (BR) effect in the green alga Chlorella vulgaris Beijerinck. BRs had the greatest effect on growth and metabolism of algae between 24 and 36 h after treatment in the range from 10 -12 to 10 -8 M. The highest growth of the content of nucleic acids and proteins was observed in the case of brassinolide (BL) at the concentration 10 -8 M in the 36th hour of cultivation. BL and its derivatives are biologically more active than castasterone (CS). The lowest stimulatory activity was shown by homoCS. The stimulatory effect of BRs in the algae was arranged in the following order: BL > 24-epiBL > homoBL > CS > 24-epiCS > homoCS. The relationship between the structure and the biological activity of BRs in stimulation of growth and changes in the content of DNA, RNA and proteins are discussed. © 2000 Éditions scientifiques et médicales Elsevier SAS Algae / brassinosteroids / Chlorella vulgaris / nucleic acids / phytohormones / proteins BL, brassinolide / BRs, brassinosteroids / CS, castasterone / 24-epiBL, 24-epibrassinolide / 24-epiCS, 24-epicastasterone / homoBL, homobrassinolide / homoCS, homocastasterone