Adenosine nucleotide ?energy charge? ratios as an ecophysiological index for microplankton communities

1981 ◽  
Vol 62 (4) ◽  
pp. 281-296 ◽  
Author(s):  
J. -C. Romano ◽  
R. Daumas
Keyword(s):  
Energy Charge ◽  
Adenosine Nucleotide

The effect of anaerobiosis on adenosine nucleotide levels inNematospiroides dubiusandTrichostrongylus colubriformis in vitro

Parasitology ◽  
1981 ◽  
Vol 83 (2) ◽  
pp. 425-433 ◽  
Author(s):  
M. J. Sharpe ◽  
D. L. Lee
Keyword(s):  
Adverse Effect ◽  
Energy Charge ◽  
Adenylate Energy Charge ◽  
Anoxic Conditions ◽  
Adenylate Pool ◽  
Nematospiroides Dubius ◽  
Adenosine Nucleotide ◽  
Sufficient Oxygen

SUMMARYThe adenosine nucleotide and adenylate energy charge values ofNematospiroides dubiusandTrichostrongylus colubriformismaintainedin vitrounder aerated and under near-anoxic conditions have been measured. Maintenance of the nematodes in both conditions had an adverse effect on their energy metabolism, but in comparing these effects it was found that the changes were more significant in those nematodes maintained in near-anoxic conditions and that the changes were more apparent in male nematodes. The smaller changes in the energy charge values of female worms, particularlyN. dubiuswhere there was no difference between worms in aerated conditions and those in near-anoxic conditions, were explained by the presence of eggs in the nematodes. At no time did the energy charge of nematodes in near-anoxic conditions fall below 0·50 but, whereas nematodes in aerated conditions were able to continue moving throughout the experiment, those in near-anoxic conditions stopped moving during the first 3 h. It is suggested that in the absence of sufficient oxygen the nematodes were able to maintain their energy charge above 0·50 by removal of AMP from the adenylate pool, resulting in the depletion of their total adenylate. The changes in the energy charge and behaviour of the nematodes are related to the survival of the nematodes in the oxygen-deficient environment which they inhabitin vivo.

scholarly journals Energetic limits to metabolic flexibility: responses of Saccharomyces cerevisiae to glucose–galactose transitions

Microbiology ◽  
2009 ◽  
Vol 155 (4) ◽  
pp. 1340-1350 ◽  
Author(s):  
J. van den Brink ◽  
M. Akeroyd ◽  
R. van der Hoeven ◽  
J. T. Pronk ◽  
J. H. de Winde ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Energy Charge ◽  
Metabolic Flexibility ◽  
Energy Status ◽  
Anaerobic Conditions ◽  
Leloir Pathway ◽  
Chemostat Cultures ◽  
Galactose Utilization ◽  
Intracellular Energy ◽  
Adenosine Nucleotide

Glucose is the favoured carbon source for Saccharomyces cerevisiae, and the Leloir pathway for galactose utilization is only induced in the presence of galactose during glucose-derepressed conditions. The goal of this study was to investigate the dynamics of glucose–galactose transitions. To this end, well-controlled, glucose-limited chemostat cultures were switched to galactose-excess conditions. Surprisingly, galactose was not consumed upon a switch to galactose excess under anaerobic conditions. However, the transcripts of the Leloir pathway were highly increased upon galactose excess under both aerobic and anaerobic conditions. Protein and enzyme-activity assays showed that impaired galactose consumption under anaerobiosis coincided with the absence of the Leloir-pathway proteins. Further results showed that absence of protein synthesis was not caused by glucose-mediated translation inhibition. Analysis of adenosine nucleotide pools revealed a fast decrease of the energy charge after the switch from glucose to galactose under anaerobic conditions. Similar results were obtained when glucose–galactose transitions were analysed under aerobic conditions with a respiratory-deficient strain. It is concluded that under fermentative conditions, the energy charge was too low to allow synthesis of the Leloir proteins. Hence, this study conclusively shows that the intracellular energy status is an important factor in the metabolic flexibility of S. cerevisiae upon changes in its environment.

Quantum Calculation of Proton and Other Charge Transfer Steps in Voltage Sensing in the Kv1.2 Channel

2019 ◽  
Author(s):  
Alisher M Kariev ◽  
Michael Green
Keyword(s):  
Charge Transfer ◽  
Energy Charge ◽  
Quantum Calculation ◽  
Quantum Calculations ◽  
Gating Current ◽  
Transmembrane Segment ◽  
Voltage Sensing ◽  
Standard Models ◽  
Charge Displacement ◽  
Voltage Sensing Domain

Quantum calculations on 976 atoms of the voltage sensing domain of the K<sub>v</sub>1.2 channel, with protons in several positions, give energy, charge transfer, and other properties. Motion of the S4 transmembrane segment that accounts for gating current in standard models is shown not to occur; there is H<sup>+ </sup>transfer instead. The potential at which two proton positions cross in energy approximately corresponds to the gating potential for the channel. The charge displacement seems approximately correct for the gating current. Two mutations are accounted for (Y266F, R300cit, cit =citrulline). The primary conclusion is that voltage sensing depends on H<sup>+</sup> transfer, not motion of arginine charges.

scholarly journals Optically Switchable MeV Ion/Electron Accelerator

2021 ◽  
Vol 11 (12) ◽  
pp. 5424
Author(s):  
Itamar Cohen ◽  
Yonatan Gershuni ◽  
Michal Elkind ◽  
Guy Azouz ◽  
Assaf Levanon ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Electron Accelerator ◽  
Energy Charge ◽  
Thin Foil ◽  
Main Pulse ◽  
Experimental Characterization ◽  
Particle Beams ◽  
Laser Accelerators

The versatility of laser accelerators in generating particle beams of various types is often promoted as a key applicative advantage. These multiple types of particles, however, are generated on vastly different irradiation setups, so that switching from one type to another involves substantial mechanical changes. In this letter, we report on a laser-based accelerator that generates beams of either multi-MeV electrons or ions from the same thin-foil irradiation setup. Switching from generation of ions to electrons is achieved by introducing an auxiliary laser pulse, which pre-explodes the foil tens of ns before irradiation by the main pulse. We present an experimental characterization of the emitted beams in terms of energy, charge, divergence, and repeatability, and conclude with several examples of prospective applications for industry and research.

scholarly journals Sugars promote graft union development in the heterograft of cucumber onto pumpkin

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Li Miao ◽  
Qing Li ◽  
Tian-shu Sun ◽  
Sen Chai ◽  
Changlin Wang ◽  
...  
Keyword(s):  
Sugar Content ◽  
Healing Process ◽  
Energy Charge ◽  
Sugar Metabolism ◽  
Union Formation ◽  
Graft Union ◽  
Positive Role ◽  
Exogenous Glucose ◽  
Expression Of Genes ◽  
Graft Interface

AbstractThe use of heterografts is widely applied for the production of several important commercial crops, but the molecular mechanism of graft union formation remains poorly understood. Here, cucumber grafted onto pumpkin was used to study graft union development, and genome-wide tempo-spatial gene expression at the graft interface was comprehensively investigated. Histological analysis suggested that resumption of the rootstock growth occurred after both phloem and xylem reconnection, and the scion showed evident callus production compared with the rootstock 3 days after grafting. Consistently, transcriptome data revealed specific responses between the scion and rootstock in the expression of genes related to cambium development, the cell cycle, and sugar metabolism during both vascular reconnection and healing, indicating distinct mechanisms. Additionally, lower levels of sugars and significantly changed sugar enzyme activities at the graft junction were observed during vascular reconnection. Next, we found that the healing process of grafted etiolated seedlings was significantly delayed, and graft success, xylem reconnection, and the growth of grafted plants were enhanced by exogenous glucose. This demonstrates that graft union formation requires the correct sugar content. Furthermore, we also found that graft union formation was delayed with a lower energy charge by the target of rapamycin (TOR) inhibitor AZD-8055, and xylem reconnection and the growth of grafted plants were enhanced under AZD-8055 with exogenous glucose treatment. Taken together, our results reveal that sugars play a positive role in graft union formation by promoting the growth of cucumber/pumpkin and provide useful information for understanding graft union healing and the application of heterografting in the future.

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