Hydrogen gas and its role in cell signalling.

Neill

2019

Plants

Nitric oxide (NO) is an immensely important signaling molecule in animals and plants. It is involved in plant reproduction, development, key physiological responses such as stomatal closure, and cell death. One of the controversies of NO metabolism in plants is the identification of enzymatic sources. Although there is little doubt that nitrate reductase (NR) is involved, the identification of a nitric oxide synthase (NOS)-like enzyme remains elusive, and it is becoming increasingly clear that such a protein does not exist in higher plants, even though homologues have been found in algae. Downstream from its production, NO can have several potential actions, but none of these will be in isolation from other reactive signaling molecules which have similar chemistry to NO. Therefore, NO metabolism will take place in an environment containing reactive oxygen species (ROS), hydrogen sulfide (H2S), glutathione, other antioxidants and within a reducing redox state. Direct reactions with NO are likely to produce new signaling molecules such as peroxynitrite and nitrosothiols, and it is probable that chemical competitions will exist which will determine the ultimate end result of signaling responses. How NO is generated in plants cells and how NO fits into this complex cellular environment needs to be understood.

Section: Interactions Of Nitric Oxide With Other Reactive Signalsmentioning

confidence: 99%

Nitric Oxide: Its Generation and Interactions with Other Reactive Signaling Compounds

Neill

2019

Plants

“…Molecular hydrogen (H 2 ) is now recognized to have biochemical effects in both animals [ 1 , 2 ] and plants [ 3 , 4 ]. Although it is a relatively inert gas, H 2 appears to have profound effects on cell activity, which can be harnessed to help plant growth, survival, and productivity [ 5 , 6 , 7 , 8 ].…”

Section: Introductionmentioning

confidence: 99%

Downstream Signalling from Molecular Hydrogen

Russell

2021

Plants

Molecular hydrogen (H2) is now considered part of the suite of small molecules that can control cellular activity. As such, H2 has been suggested to be used in the therapy of diseases in humans and in plant science to enhance the growth and productivity of plants. Treatments of plants may involve the creation of hydrogen-rich water (HRW), which can then be applied to the foliage or roots systems of the plants. However, the molecular action of H2 remains elusive. It has been suggested that the presence of H2 may act as an antioxidant or on the antioxidant capacity of cells, perhaps through the scavenging of hydroxyl radicals. H2 may act through influencing heme oxygenase activity or through the interaction with reactive nitrogen species. However, controversy exists around all the mechanisms suggested. Here, the downstream mechanisms in which H2 may be involved are critically reviewed, with a particular emphasis on the H2 mitigation of stress responses. Hopefully, this review will provide insight that may inform future research in this area.

“…Several other reactive compounds also need to be considered to be involved in the control of cellular function [1]. Among these is hydrogen gas (H2) [3], a compound gaining prominence in the literature. However, to be considered as part of a suite of signaling molecules, the production, movement, perception, roles, and removal of the signaling compound need to be considered [2], and this would also apply to H2 if it is to be accepted as a regulatory component in cells.…”

Section: Introductionmentioning

confidence: 99%

“…In treating organisms with H2, there are various methods which can be used [3]. Although H2 can be used in the gaseous form, more often a saturated solution is created and added to the biological system.…”

Section: Introductionmentioning

confidence: 99%

“…Having provided evidence that organisms can make or be exposed to H2, that H2 can move around cells, and importantly, that H2 can have effects of cells-all good measures of the involvement of H2 in cell signaling events [3]-to truly be able to be involved in biological systems, H2 would need to be perceived. One mechanism, that has been studied which may account for some of the effects of molecular hydrogen is the heme oxygenase (HO) system.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Hydrogen Gas, ROS Metabolism, and Cell Signaling: Are Hydrogen Spin States Important?

2018

ROS

It is becoming accepted that treatment with hydrogen gas (H2) has profound and often beneficial effects on cells from both animals and plants. Future uses, which have been suggested, include for cancer treatment, for alleviating symptoms of Parkinson's disease and ischemia, and for improving crops in agriculture. However, besides a direct interaction with hydroxyl radicals, there is little resolution of how H2 is having biological effects. Dihydrogen is known to exist in two spin states, ortho and para, and to have paramagnetic properties. The interconversion of hydrogen spin states has been reported in the presence of signaling molecules such as nitric oxide, and in the vicinity of transition metals and organometallic compounds. Therefore, it is proposed here that the relationship between the effects of hydrogen gas and paramagnetism is investigated as a possible mechanism which could account for the alterations of cell function reported following H2 treatment.