Methylglyoxal (MG), a reactive α, β-dicarbonyl ketoaldehyde, is unavoidable by-product of several metabolic pathways, it has long been considered as cytotoxin at high concentration, but now is ...emerging signal molecule function at low concentration in plants. Thus, MG homeostasis in plant cells is very important to exert its physiological function. Glyoxalase system, mainly including glyoxalase I and glyoxalase II, is the major regulator of MG homeostasis in plants. Recent years, research on MG and its detoxification system glyoxalase has attracted much attention in plant biology. Based on the current progress on MG and glyoxalase system, in this review, MG biosynthesis and degradation; determination of MG; MG as signal iniator crosstalk with Ca²⁺, reactive oxygen species and abscisic acid; satl, heavy metal, drought, cold and heat tolerance involved in MG and glyoxalase system; stomatal movement; seed germiantion; and cell division and organ differentiation, were summarized. Meanwhile, research direction in the future was presented.
Hydrogen sulfide (H2S) which is considered as a novel gasotransmitter after reactive oxygen species and nitric oxide in plants has dual character, that is, toxicity that inhibits cytochrome oxidase ...at high concentration and as signal molecule which is involved in plant growth, development, and the acquisition of tolerance to adverse environments such as extreme temperature, drought, salt, and heavy metal stress at low concentration. Therefore, H2S homeostasis is very important in plant cells. The level of H2S in plant cells is regulated by its synthetic and degradative enzymes, L-/D-cysteine desulfhydrase (L-/D-DES), sulfite reductase (SiR), and cyanoalanine synthase (CAS), which are responsible for H2S synthesis, while cysteine synthase (CS) takes charge of the degradation of H2S, but its reverse reaction also can produce H2S. Here, after crude enzyme is extracted from plant tissues, the activities of L-/D-DES, SiR, CAS, and CS are measured by spectrophotometry, the aim is to further understand homeostasis of H2S in plant cells and its potential mechanisms.
Janus particles possess two or more distinct domains that are anisotropic in composition or surface features. They integrate different or even incompatible properties within a single particle, making ...them possible to perform diverse functions and multiple tasks simultaneously. Advances in micro/nanorobots demonstrate that they can effectively convert diverse energy sources into movement and reach target locations with precision. Integration of Janus structure with micro/nanobots is emerging as a promising tool for biomedical applications. In this review, the fabrication and energy sources of Janus micro/nanorobots are briefly introduced. After that, the recent progress of Janus micro/nanorobots for biomedicine, with a special focus on their applications for cargo delivery, bioimaging, biosensing, surgery, and therapy are presented and discussed. The application of Janus micro/nanorobots in biomedicine still faces serious challenges from fabrication, engines, biocompatibility, and biodegradation for their widespread in clinical situations. Nevertheless, a few emerging materials and approaches offer potential solutions to these problems.
Recent trends are shown in Janus micro/nanorobots (JRs) mainly propelled by physical power, chemical power and biological power and their biomedical applications including cargo delivery, bioimaging, biosensing, surgery, and therapy. JRs exhibit precise cargo delivery by targeted motion, accurate bioimaging by real‐time tracking positions, enhanced biosensing by improving mass transfer, and precise surgery and therapy by enhancing tissue penetration.
It is well known that glutamate (Glu), a neurotransmitter in human body, is a protein amino acid. It plays a very important role in plant growth and development. Nowadays, Glu has been found to ...emerge as signaling role. Under normal conditions, Glu takes part in seed germination, root architecture, pollen germination, and pollen tube growth. Under stress conditions, Glu participates in wound response, pathogen resistance, response and adaptation to abiotic stress (such as salt, cold, heat, and drought), and local stimulation (abiotic or biotic stress)-triggered long distance signaling transduction. In this review, in the light of the current opinion on Glu signaling in plants, the following knowledge was updated and discussed. 1) Glu metabolism; 2) signaling role of Glu in plant growth, development, and response and adaptation to environmental stress; as well as 3) the underlying research directions in the future. The purpose of this review was to look forward to inspiring the rapid development of Glu signaling research in plant biology, particularly in the field of stress biology of plants.
Plants growing under field conditions are constantly exposed, either simultaneously or sequentially, to more than one abiotic stress factor. Plants have evolved sophisticated sensory systems to ...perceive a number of stress signals that allow them to activate the most adequate response to grow and survive in a given environment. Recently, cross-stress tolerance (i.e. tolerance to a second, strong stress after a different type of mild primary stress) has gained attention as a potential means of producing stress-resistant crops to aid with global food security. Heat or cold priming-induced cross-tolerance is very common in plants and often results from the synergistic co-activation of multiple stress signalling pathways, which involve reactive nitrogen species (RNS), reactive oxygen species (ROS), reactive carbonyl species (RCS), plant hormones and transcription factors. Recent studies have shown that the signalling functions of ROS, RNS and RCS, most particularly hydrogen peroxide, nitric oxide (NO) and methylglyoxal (MG), provide resistance to abiotic stresses and underpin cross-stress tolerance in plants by modulating the expression of genes as well as the post-translational modification of proteins. The current review highlights the key regulators and mechanisms underlying heat or cold priming-induced cross-stress tolerance in plants, with a focus on ROS, MG and NO signalling, as well as on the role of antioxidant and glyoxalase systems, osmolytes, heat-shock proteins (HSPs) and hormones. Our aim is also to provide a comprehensive idea on the topic for researchers using heat or cold priming-induced cross-tolerance as a mechanism to improve crop yields under multiple abiotic stresses.
Hydrogen sulfide (H2S) has long been considered as a phytotoxin but, nowadays, as a novel signaling molecule at low concentration in plants, which is involved in plant growth, development, and the ...acquisition of tolerance to abiotic and biotic stresses. H2S is commonly found only in very small amounts in most biological systems. To further understand H2S functions, accurate measurement of H2S concentration in plants is very important. In this chapter, quantificational methods of H2S in plant tissues, namely, methylene blue (MB) and 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB) methods, are introduced; the former has higher sensitivity than that of the latter, and the determination limits of MB and DTNB methods are 1.5×10(-7)M (0.005 μg/ml) and 3.7×10(-6)M (0.13 μg/ml), respectively, hoping to stimulate more research into H2S signal molecule in plants.
For a long time, hydrogen sulfide (H
S) has been considered as merely a toxic by product of cell metabolism, but nowadays is emerging as a novel gaseous signal molecule, which participates in seed ...germination, plant growth and development, as well as the acquisition of stress tolerance including cross-adaptation in plants. Cross-adaptation, widely existing in nature, is the phenomenon in which plants expose to a moderate stress can induce the resistance to other stresses. The mechanism of cross-adaptation is involved in a complex signal network consisting of many second messengers such as Ca
, abscisic acid, hydrogen peroxide and nitric oxide, as well as their crosstalk. The cross-adaptation signaling is commonly triggered by moderate environmental stress or exogenous application of signal molecules or their donors, which in turn induces cross-adaptation by enhancing antioxidant system activity, accumulating osmolytes, synthesizing heat shock proteins, as well as maintaining ion and nutrient balance. In this review, based on the current knowledge on H
S and cross-adaptation in plant biology, H
S homeostasis in plant cells under normal growth conditions; H
S signaling triggered by abiotic stress; and H
S-induced cross-adaptation to heavy metal, salt, drought, cold, heat, and flooding stress were summarized, and concluded that H
S might be a candidate signal molecule in plant cross-adaptation. In addition, future research direction also has been proposed.
Although plasma corticosterone is considered the main glucocorticoid involved in regulation of stress responses in rodents, the presence of plasma cortisol and whether its level can be used as an ...indicator for rodent activation of stress remain to be determined. In this study, effects of estrous cycle stage, circadian rhythm, and acute and chronic (repeated or unpredictable) stressors of various severities on dynamics and correlation of serum cortisol and corticosterone were examined in mice. A strong (r = 0.6-0.85) correlation between serum cortisol and corticosterone was observed throughout the estrous cycle, all day long, and during acute or repeated restraints, chronic unpredictable stress and acute forced swimming or heat stress. Both hormones increased to the highest level on day 1 of repeated-restraint or unpredictable stresses, but after that, whereas the concentration of cortisol did not change, that of corticosterone showed different dynamics. Thus, whereas corticosterone declined dramatically during repeated restraints, it remained at the high level during unpredictable stress. During forced swimming or heat stress, whereas cortisol increased to the highest level within 3 min., corticosterone did not reach maximum until 40 min. of stress. Analysis with HPLC and HPLC-MS further confirmed the presence of cortisol in mouse serum. Taken together, results (i) confirmed the presence of cortisol in mouse serum and (ii) suggested that mouse serum cortisol and corticosterone are closely correlated in dynamics under different physiological or stressful conditions, but, whereas corticosterone was a more adaptation-related biomarker than cortisol during chronic stress, cortisol was a quicker responder than corticosterone during severe acute stress.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Hydrogen sulfide (H2S) and abscisic acid (ABA), as a signaling molecule and stress hormone, their crosstalk-induced thermotolerance in maize seedlings and its underlying mechanism were elusive. In ...this paper, H2S and ABA crosstalk as well as the underlying mechanism of crosstalk-induced thermotolerance in maize seedlings were investigated. The data show that endogenous levels of H2S and ABA in maize seedlings could be mutually induced by regulating their metabolic enzyme activity and gene expression under non-heat stress (non-HS) and HS conditions. Furthermore, H2S and ABA alone or in combination significantly increase thermotolerance in maize seedlings by improving the survival rate (SR) and mitigating biomembrane damage. Similarly, the activity of the reactive oxygen species (ROS)-scavenging system, including enzymatic antioxidants catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (POD), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and superoxide dismutase (SOD), as well as the non-enzymatic antioxidants reduced ascorbic acid (AsA), carotenoids (CAR), flavone (FLA), and total phenols (TP), was enhanced by H2S and ABA alone or in combination in maize seedlings. Conversely, the ROS level (mainly hydrogen peroxide and superoxide radical) was weakened by H2S and ABA alone or in combination in maize seedlings under non-HS and HS conditions. These data imply that the ROS-scavenging system played an essential role in H2S-ABA crosstalk-induced thermotolerance in maize seedlings.
Abiotic stresses are the most common harmful factors, adversely affecting all aspects of plants’ life. Plants have to elicit appropriate responses against multifaceted effects of abiotic stresses by ...reprogramming various cellular processes. Signaling molecules play vital roles in sensing environmental stimuli to modulate gene expression, metabolism and physiological processes in plants to cope with the adverse effects. Methylglyoxal (MG), a dicarbonyl compound, is known to accumulate in cells as a byproduct of various metabolic pathways, including glycolysis. Several works in recent years have demonstrated that MG could play signaling roles via Ca2+, reactive oxygen species (ROS), K+ and abscisic acid. Recently, global gene expression profiling has shown that MG could induce signaling cascades, and an overlap between MG-responsive and stress-responsive signaling events might exist in plants. Once overaccumulated in cells, MG can provoke detrimental effects by generating ROS, forming advanced glycation end products and inactivating antioxidant systems. Plants are also equipped with MG-detoxifying glyoxalase system to save cellular organelles from MG toxicity. Since MG has regulatory functions in plant growth and development, and glyoxalase system is an integral component of abiotic stress adaptation, an in-depth understanding on MG metabolism and glyoxalase system will help decipher mechanisms underlying plant responses to abiotic stresses. Here, we provide a comprehensive update on the current knowledge of MG production and detoxification in plants, and highlight the putative functions of glyoxalase system in mediating plant defense against abiotic stresses. We particularly emphasize on the dual roles of MG and its connection with glutathione-related redox regulation, which is crucial for plant defense and adaptive responses under changing environmental conditions.
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•Plants induce methylglyoxal (MG) production under abiotic stress conditions.•MG is toxic at high concentrations but it has signaling roles at low concentrations.•MG-scavenging glyoxalse system is a vital part of plant defense under abiotic stresses.•MG metabolism may perturb redox balance by affecting GSH and GSH/GSSG ratio.
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