Photosystem I Inhibition, Protection and Signalling: Knowns and Unknowns

Photosynthesis is the process that harnesses, converts and stores light energy in the form of chemical energy in bonds of organic compounds. Oxygenic photosynthetic organisms (i.e., plants, algae and cyanobacteria) employ an efficient apparatus to split water and transport electrons to high-energy electron acceptors. The photosynthetic system must be finely balanced between energy harvesting and energy utilisation, in order to limit generation of dangerous compounds that can damage the integrity of cells. Insight into how the photosynthetic components are protected, regulated, damaged, and repaired during changing environmental conditions is crucial for improving photosynthetic efficiency in crop species. Photosystem I (PSI) is an integral component of the photosynthetic system located at the juncture between energy-harnessing and energy consumption through metabolism. Although the main site of photoinhibition is the photosystem II (PSII), PSI is also known to be inactivated by photosynthetic energy imbalance, with slower reactivation compared to PSII; however, several outstanding questions remain about the mechanisms of damage and repair, and about the impact of PSI photoinhibition on signalling and metabolism. In this review, we address the knowns and unknowns about PSI activity, inhibition, protection, and repair in plants. We also discuss the role of PSI in retrograde signalling pathways and highlight putative signals triggered by the functional status of the PSI pool.

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Oligodendrocyte Bioenergetics in Health and Disease

The Neuroscientist ◽

10.1177/1073858418793077 ◽

2018 ◽

Vol 25 (4) ◽

pp. 334-343 ◽

Cited By ~ 14

Author(s):

Lauren Rosko ◽

Victoria N. Smith ◽

Reiji Yamazaki ◽

Jeffrey K. Huang

Keyword(s):

Central Nervous System ◽

Nervous System ◽

High Energy ◽

The Body ◽

Metabolic Coupling ◽

Energy Demands ◽

Metabolic Role ◽

The Central Nervous System ◽

The Impact

The human brain weighs approximately 2% of the body; however, it consumes about 20% of a person’s total energy intake. Cellular bioenergetics in the central nervous system involves a delicate balance between biochemical processes engaged in energy conversion and those responsible for respiration. Neurons have high energy demands, which rely on metabolic coupling with glia, such as with oligodendrocytes and astrocytes. It has been well established that astrocytes recycle and transport glutamine to neurons to make the essential neurotransmitters, glutamate and GABA, as well as shuttle lactate to support energy synthesis in neurons. However, the metabolic role of oligodendrocytes in the central nervous system is less clear. In this review, we discuss the energetic demands of oligodendrocytes in their survival and maturation, the impact of altered oligodendrocyte energetics on disease pathology, and the role of energetic metabolites, taurine, creatine, N-acetylaspartate, and biotin, in regulating oligodendrocyte function.

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THE INFLUENCE OF MORPHOMETRIC INDICATORS OF THE RELIEF ON THE FORMATION OF LANDSCAPES OF THE SOUTHEASTERN SLOPE OF THE GREATER CAUCASUS

Bulletin of Taras Shevchenko National University of Kyiv Geography ◽

10.17721/1728-2721.2021.78-79.8 ◽

2021 ◽

pp. 53-59

Author(s):

A. Ismailova ◽

Keyword(s):

Close Correlation ◽

Environmental Safety ◽

High Energy ◽

Mountain Areas ◽

Greater Caucasus ◽

Mountain Landscape ◽

Landscape Unit ◽

Steep Slopes ◽

The Impact

Purpose: To reveal the role of high energy of slope relief in the formation and differentiation of modern mountain geosystems of the Southeastern slope of the Greater Caucasus by assessing the degree of horizontal dissection, slopes of slopes and landscape-morphometric tension of territories with various landscape complexes with subsequent mapping of the ecogeographic situation in order to ensure rational land use and environmental safety. Methodology and Approach: On the basis of field and office studies, data on the state of the soil and vegetation cover, the author analyzed the impact of morphometric indicators on the exodynamic conditions of landscape belts, identified individual landscape-morphological blocks according to the degree of morphometric tension, schematic maps reflecting the impact of horizontal dissection and slopes of slopes on the natural complexes of the territory. Results: The author, through a comparative analysis of quantitative morphometric indicators from different ranks of landscape complexes, showed that there is a close correlation between them, i.e. differentiation, fragmentation and small contour of mountain landscape geosystems, and each landscape unit is distinguished by its own morphometric indicators, which also determine their exogeodynamic stability. It was revealed that the highest intensity of 5 points is characteristic of the territory covering steep slopes within the heights, which are characterized by the development of subnival, alpine meadow and subalpine complexes. The results of field and office studies were reflected in the compiled cartographic materials, which made it possible to carry out a spatial analysis of the development of the exodynamic situation on the territory of the southeastern slope of the Greater Caucasus. Theoretical and Practical implications: Based on the generalization of the results of the research carried out, the territories most exposed to exogenous relief-forming processes can be identified, a more detailed study is carried out and the exodynamic situation is more objectively assessed. The results of the study will make it possible to carry out effective economic planning, to identify priority areas for the implementation of anti-erosion and phyto-reclamation measures in mountain areas.

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Cloud distribution evaluated by the WRF model during the EUSO-SPB1 flight

EPJ Web of Conferences ◽

10.1051/epjconf/201921005006 ◽

2019 ◽

Vol 210 ◽

pp. 05006

Author(s):

K Shinozaki ◽

S Monte ◽

S Ferrarese ◽

M Manfrin ◽

ME Bertaina ◽

...

Keyword(s):

Photon Counting ◽

Wrf Model ◽

Cosmic Ray ◽

High Energy ◽

Weather Research And Forecasting ◽

Fluorescence Detector ◽

Air Shower ◽

Detection Mode ◽

The Impact

EUSO-SPB1 was a balloon-borne mission of the JEM-EUSO (Joint Experiment Missions for Extreme Universe Space Observatory) Program aiming at the ultra-high energy cosmic ray (UHECR) observations from space. We operated the EUSO-SPB1 telescope consisting of 1 m2 Fresnel refractive optics and multi-anode photomultiplier tubes. With a total of 2304 channels, each performed the photon counting every 2.5 µs, allowing for spatiotemporal imaging of the air shower events in an ~ 11°× 11° field of view. EUSO-SPB1 was the first balloon-borne fluorescence detector with a potential to detect air shower events initiated by the EeV energy cosmic rays. On 24 April 2017 UTC, EUSO-SPB1 was launched on the NASA’s Super Pressure Balloon that flew at ~16 – 33 km flight height for ~12 days. Before the flight was terminated, ~27 hours of data acquired in the air shower detection mode were transmitted to the ground. In the present work, we aim at evaluating the role of the clouds during the operation of EUSO-SPB1. We employ the WRF (Weather Research and Forecasting) model to numerically simulate the cloud distribution below EUSO-SPB1. We discuss the key results of the WRF model and the impact of the clouds on the air shower measurement and the efficiency of the cosmic ray observation. The present work is a part of the collaborative effort to estimate the exposure for air shower detections.

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Intergroup Threat and Outgroup Attitudes

Social Psychology ◽

10.1027/1864-9335/a000127 ◽

2013 ◽

Vol 44 (5) ◽

pp. 311-319 ◽

Cited By ~ 12

Author(s):

Marco Brambilla ◽

David A. Butz

Keyword(s):

Gay Men ◽

Social Group ◽

Welfare Recipients ◽

Intergroup Attitudes ◽

Social Policies ◽

Intergroup Threat ◽

Economic Threat ◽

The Impact ◽

General Climate

Two studies examined the impact of macrolevel symbolic threat on intergroup attitudes. In Study 1 (N = 71), participants exposed to a macrosymbolic threat (vs. nonsymbolic threat and neutral topic) reported less support toward social policies concerning gay men, an outgroup whose stereotypes implies a threat to values, but not toward welfare recipients, a social group whose stereotypes do not imply a threat to values. Study 2 (N = 78) showed that, whereas macrolevel symbolic threat led to less favorable attitudes toward gay men, macroeconomic threat led to less favorable attitudes toward Asians, an outgroup whose stereotypes imply an economic threat. These findings are discussed in terms of their implications for understanding the role of a general climate of threat in shaping intergroup attitudes.

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