scholarly journals Active Coacervate Droplets Are Protocells That Grow and Resist Ostwald Ripening

2021 ◽  
Author(s):  
Karina K. Nakashima ◽  
Merlijn H. I. van Haren ◽  
Alain A. M. André ◽  
Irina Robu ◽  
Evan Spruijt
Keyword(s):  
Electrostatic Interactions ◽  
Protein Concentration ◽  
Ostwald Ripening ◽  
Population Level ◽  
Cellular Growth ◽  
Droplet Growth ◽  
Experimental Conditions ◽  
Active Processes ◽  
Cellular Behaviour ◽  
Insight Into

Active coacervate droplets are liquid condensates coupled to a chemical reaction that turns over their components, keeping the droplets out of equilibrium. This turnover can be used to drive active processes such as growth, and provide an insight into the chemical requirements underlying (proto)cellular behaviour. Moreover, controlled growth is a key requirement to achieve population fitness and survival. Here we present a minimal, nucleotide-based coacervate model for active droplets, and report three key findings that make these droplets into evolvable protocells. First, we show that coacervate droplets form and grow by the fuel-driven synthesis of new coacervate material. Second, we find that these droplets do not undergo Ostwald ripening, which we attribute to the attractive electrostatic interactions within complex coacervates, active or passive. Finally, we show that the droplet growth rate reflects experimental conditions such as substrate, enzyme and protein concentration, and that a different droplet composition (addition of RNA) leads to altered growth rates and droplet fitness. These findings together make active coacervate droplets a powerful platform to mimic cellular growth at a single-droplet level, and to study fitness at a population level.<br>

scholarly journals Active Coacervate Droplets Are Protocells That Grow and Resist Ostwald Ripening

2021 ◽  
Author(s):  
Karina K. Nakashima ◽  
Merlijn H. I. van Haren ◽  
Alain A. M. André ◽  
Irina Robu ◽  
Evan Spruijt
Keyword(s):  
Electrostatic Interactions ◽  
Protein Concentration ◽  
Ostwald Ripening ◽  
Population Level ◽  
Cellular Growth ◽  
Droplet Growth ◽  
Experimental Conditions ◽  
Active Processes ◽  
Cellular Behaviour ◽  
Insight Into

Active coacervate droplets are liquid condensates coupled to a chemical reaction that turns over their components, keeping the droplets out of equilibrium. This turnover can be used to drive active processes such as growth, and provide an insight into the chemical requirements underlying (proto)cellular behaviour. Moreover, controlled growth is a key requirement to achieve population fitness and survival. Here we present a minimal, nucleotide-based coacervate model for active droplets, and report three key findings that make these droplets into evolvable protocells. First, we show that coacervate droplets form and grow by the fuel-driven synthesis of new coacervate material. Second, we find that these droplets do not undergo Ostwald ripening, which we attribute to the attractive electrostatic interactions within complex coacervates, active or passive. Finally, we show that the droplet growth rate reflects experimental conditions such as substrate, enzyme and protein concentration, and that a different droplet composition (addition of RNA) leads to altered growth rates and droplet fitness. These findings together make active coacervate droplets a powerful platform to mimic cellular growth at a single-droplet level, and to study fitness at a population level.<br>

scholarly journals Active coacervate droplets are protocells that grow and resist Ostwald ripening

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Karina K. Nakashima ◽  
Merlijn H. I. van Haren ◽  
Alain A. M. André ◽  
Irina Robu ◽  
Evan Spruijt
Keyword(s):  
Electrostatic Interactions ◽  
Ostwald Ripening ◽  
Population Level ◽  
Cellular Growth ◽  
Droplet Growth ◽  
Experimental Conditions ◽  
Active Processes ◽  
Cellular Behaviour ◽  
Translational Entropy ◽  
Insight Into

AbstractActive coacervate droplets are liquid condensates coupled to a chemical reaction that turns over their components, keeping the droplets out of equilibrium. This turnover can be used to drive active processes such as growth, and provide an insight into the chemical requirements underlying (proto)cellular behaviour. Moreover, controlled growth is a key requirement to achieve population fitness and survival. Here we present a minimal, nucleotide-based coacervate model for active droplets, and report three key findings that make these droplets into evolvable protocells. First, we show that coacervate droplets form and grow by the fuel-driven synthesis of new coacervate material. Second, we find that these droplets do not undergo Ostwald ripening, which we attribute to the attractive electrostatic interactions and translational entropy within complex coacervates, active or passive. Finally, we show that the droplet growth rate reflects experimental conditions such as substrate, enzyme and protein concentration, and that a different droplet composition (addition of RNA) leads to altered growth rates and droplet fitness. These findings together make active coacervate droplets a powerful platform to mimic cellular growth at a single-droplet level, and to study fitness at a population level.

scholarly journals Methane and Inflammation - A Review (Fight Fire with Fire)

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Marietta Zita Poles ◽  
László Juhász ◽  
Mihály Boros
Keyword(s):  
Stress Responses ◽  
Nitrosative Stress ◽  
Ischemia Reperfusion ◽  
Signalling Pathways ◽  
Experimental Conditions ◽  
Neuroprotective Effects ◽  
Oxidative And Nitrosative Stress ◽  
Carbohydrate Fermentation ◽  
Insight Into

AbstractMammalian methanogenesis is regarded as an indicator of carbohydrate fermentation by anaerobic gastrointestinal flora. Once generated by microbes or released by a non-bacterial process, methane is generally considered to be biologically inactive. However, recent studies have provided evidence for methane bioactivity in various in vivo settings. The administration of methane either in gas form or solutions has been shown to have anti-inflammatory and neuroprotective effects in an array of experimental conditions, such as ischemia/reperfusion, endotoxemia and sepsis. It has also been demonstrated that exogenous methane influences the key regulatory mechanisms and cellular signalling pathways involved in oxidative and nitrosative stress responses. This review offers an insight into the latest findings on the multi-faceted organ protective activity of exogenous methane treatments with special emphasis on its versatile effects demonstrated in sepsis models.

scholarly journals Behavioral Triggers of Skin Conductance Responses and Their Neural Correlates in the Primate Amygdala

2009 ◽  
Vol 101 (4) ◽  
pp. 1749-1754 ◽  
Author(s):  
Christopher M. Laine ◽  
Kevin M. Spitler ◽  
Clayton P. Mosher ◽  
Katalin M. Gothard
Keyword(s):  
Skin Conductance ◽  
Single Unit ◽  
Population Level ◽  
Emotional Reaction ◽  
Neural Population ◽  
Experimental Conditions ◽  
Indirect Measure ◽  
Skin Conductance Responses ◽  
The Right ◽  
Sympathetic Arousal

The amygdala plays a crucial role in evaluating the emotional significance of stimuli and in transforming the results of this evaluation into appropriate autonomic responses. Lesion and stimulation studies suggest involvement of the amygdala in the generation of the skin conductance response (SCR), which is an indirect measure of autonomic activity that has been associated with both emotion and attention. It is unclear if this involvement marks an emotional reaction to an external stimulus or sympathetic arousal regardless of its origin. We recorded skin conductance in parallel with single-unit activity from the right amygdala of two rhesus monkeys during a rewarded image viewing task and while the monkeys sat alone in a dimly lit room, drifting in and out of sleep. In both experimental conditions, we found similar SCR-related modulation of activity at the single-unit and neural population level. This suggests that the amygdala contributes to the production or modulation of SCRs regardless of the source of sympathetic arousal.

Growth Mechanism and Electrochemical Properties of Porous Hollow Tin Dioxide Nanospheres

NANO ◽  
2015 ◽  
Vol 10 (06) ◽  
pp. 1550087 ◽  
Author(s):  
Youwen Yang ◽  
Dongming Ma ◽  
Ting Cheng ◽  
Yuanhao Gao ◽  
Guanghai Li
Keyword(s):  
Growth Mechanism ◽  
Tin Dioxide ◽  
Ostwald Ripening ◽  
Lithium Ion ◽  
Average Diameter ◽  
Reversible Capacity ◽  
Cycling Performance ◽  
Experimental Conditions ◽  
Electrochemical Tests ◽  
Hydrolysis Method

Porous hollow SnO 2 nanospheres were prepared by means of enforced Sn 2+ hydrolysis method under hydrochloric acid medium. These hollow nanospheres with an average diameter of 220nm had a very thin shell thickness of about 40nm and were surrounded by elongated octahedral-like nanoparticles with the apex oriented outside. The experimental conditions, such as HCl content, reaction temperature and time directly dominated the morphology, structure and crystallinity of the obtained samples. A pre-oxidation-nucleation-growth mechanism and inside-out Ostwald-ripening method was proposed on the basis of the previous research and time-dependent experiments. Electrochemical tests showed that the porous hollow SnO 2 nanospheres exhibited improved cycling performance for anode materials of lithium-ion batteries, which retained a high reversible capacity of 540.0mAhg-1, and stable cyclic retention at 120th cycle.

scholarly journals Insight into Inhibitor Binding in the Eukaryotic Proteasome: Computations of the 20S CP

2018 ◽  
Vol 19 (12) ◽  
pp. 3858
Author(s):  
Milan Hodošček ◽  
Nadia Elghobashi-Meinhardt
Keyword(s):  
Electrostatic Interactions ◽  
Active Sites ◽  
Sampling Period ◽  
Md Simulations ◽  
Structural Features ◽  
Relaxation Dynamics ◽  
Inhibitor Binding ◽  
Computational Analyses ◽  
Insight Into ◽  
Proteolytic Chamber

A combination of molecular dynamics (MD) simulations and computational analyses uncovers structural features that may influence substrate passage and exposure to the active sites within the proteolytic chamber of the 20S proteasome core particle (CP). MD simulations of the CP reveal relaxation dynamics in which the CP slowly contracts over the 54 ns sampling period. MD simulations of the SyringolinA (SylA) inhibitor within the proteolytic B 1 ring chamber of the CP indicate that favorable van der Waals and electrostatic interactions account for the predominant association of the inhibitor with the walls of the proteolytic chamber. The time scale required for the inhibitor to travel from the center of the proteolytic chamber to the chamber wall is on the order of 4 ns, accompanied by an average energetic stabilization of approximately −20 kcal/mol.

scholarly journals Altered acrylic acid concentrations in hard and soft corals exposed to deteriorating water conditions

FACETS ◽  
2017 ◽  
Vol 2 (1) ◽  
pp. 531-544 ◽  
Author(s):  
Lori S.H. Westmoreland ◽  
Jennifer N. Niemuth ◽  
Hanna S. Gracz ◽  
Michael K. Stoskopf
Keyword(s):  
Acrylic Acid ◽  
Marine Algae ◽  
Soft Coral ◽  
Resonance Spectroscopy ◽  
Additional Insight ◽  
Experimental Conditions ◽  
Animal Metabolism ◽  
Reef Decline ◽  
Reliable Marker ◽  
Insight Into

A reliable marker of early coral response to environmental stressors can help guide decision-making to mitigate global coral reef decline by detecting problems before the development of clinically observable disease. We document the accumulation of acrylic acid in two divergent coral taxa, stony small polyp coral ( Acropora sp.) and soft coral ( Lobophytum sp.), in response to deteriorating water quality characterized by moderately increased ammonia (0.25 ppm) and phosphate (0.15 ppm) concentrations and decreased calcium (360 ppm) concentration, using nuclear magnetic resonance spectroscopy (NMR)-based metabolomic techniques. Changes in acrylic acid concentration in polyp tissues free of zooxanthellae suggest that acrylic acid could be a product of animal metabolism and not exclusively a metabolic by-product of the osmolyte dimethylsulfoniopropionate (DMSP) in marine algae or bacteria. Our findings build on previously documented depletions of acrylic acid in wild coral potentially correlated to temperature stress and provide additional insight into approaches to further characterize the nature of the metabolic accumulation of acrylic acid under controlled experimental conditions.

scholarly journals Longer, More Active Commute, but Still not Very Active: Five-Year Physical Activity and Travel Behavior Change in a University Population

2019 ◽  
Vol 16 (13) ◽  
pp. 2420
Author(s):  
Lina Engelen ◽  
Erika Bohn-Goldbaum ◽  
Melanie Crane ◽  
Martin Mackey ◽  
Chris Rissel
Keyword(s):  
Physical Activity ◽  
Travel Behavior ◽  
Online Survey ◽  
Population Level ◽  
Active Travel ◽  
Physical Activity Monitoring ◽  
University Population ◽  
The University ◽  
Active Commute ◽  
Insight Into

Active travel can support the achievement of recommended levels of physical activity. Monitoring travel behavior of university students and staff provides a useful insight into patterns of regional travel and population level changes in physical activity. This study sought to evaluate current travel and physical activity behaviors in a university population and to determine whether these changed over time. An online survey of travel behavior and physical activity was conducted at the University of Sydney, Australia. The survey was actively promoted for three weeks prior to the release of the survey among staff and students, which asked about travel behavior on a specific day in September 2017. The survey questions were the same as those used in a similar online survey conducted across the University in 2012. In total, 4359 People completed the survey, representing 10.8% of staff and 4.1% of students. Approximately two thirds of survey respondents were students, in both the 2012 and 2017 surveys. Compared with 2012, there was an increase in active travel to the University in 2017 from increased walking and train travel. Compared to 2012, in 2017 there was an increase in average minutes walked by about nine minutes, and less time spent sitting. Trip lengths increased, with 68% of trips taking longer than 30 min in 2017. The amount of time spent in low–moderate levels physical activity increased between 2012 and 2017, potentially related to active travel behavior. Citywide changes towards a system-wide transport fare structure was the biggest change in the transport environment between the two surveys and may have contributed to increased train travel.

THE USE OF POLYSTYRENE–ALLERGEN CONJUGATES FOR THE REMOVAL OF ANTIBODIES FROM SERA OF ALLERGIC INDIVIDUALS

1960 ◽  
Vol 38 (1) ◽  
pp. 1249-1253
Author(s):  
L. Gyenes ◽  
A. H. Sehon
Keyword(s):  
Hydrochloric Acid ◽  
Protein Concentration ◽  
Complete Removal ◽  
Experimental Conditions ◽  
Comparative Analyses ◽  
Before And After

Polystyrene–ragweed conjugates were shown to remove specifically antibodies from sera of individuals allergic to ragweed. This observation is considered evidence that firm combination occurs in vitro between allergic antibodies and the homologous allergens. Comparative analyses of allergic sera before and after exposure to immunosorbents indicated that complete removal of skin-sensitizing, blocking, and hemagglutinating antibodies did not result in a measurable decrease in protein concentration, thus demonstrating that these factors are present only in minute amounts.Attempts to eîute allergic antibodies from the homologous immunosorbents under various experimental conditions did not lead to their recovery in significant yields; these antibodies could be recovered in small amounts by dissociation with hydrochloric acid at pH 3.

scholarly journals Evidence of reactivation of a hydrothermal system from seismic anisotropy changes

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Maria Saade ◽  
Kohtaro Araragi ◽  
Jean Paul Montagner ◽  
Edouard Kaminski ◽  
Philippe Roux ◽  
...  
Keyword(s):  
Seismic Anisotropy ◽  
Seismic Velocity ◽  
Temporal Variations ◽  
Volcanic Area ◽  
Velocity Measurements ◽  
Noise Interferometry ◽  
Volcanic Monitoring ◽  
Monitoring And Forecasting ◽  
Active Processes ◽  
Insight Into

AbstractSeismic velocity measurements have revealed that the Tohoku-Oki earthquake affected velocity structures of volcanic zones far from the epicenter. Using a seismological method based on ambient seismic noise interferometry, we monitored the anisotropy in the Mount Fuji area during the year 2011, in which the Tohoku-Oki earthquake occurred (Mw = 9.0). Here we show that even at 400 km from the epicenter, temporal variations of seismic anisotropy were observed. These variations can be explained by changes in the alignment of cracks or fluid inclusions beneath the volcanic area due to stress perturbations and the propagation of a hydrothermal fluid surge beneath the Hakone hydrothermal volcanic area. Our results demonstrate how a better understanding of the origin of anisotropy and its temporal changes beneath volcanoes and in the crust can provide insight into active processes, and can be used as part of a suite of volcanic monitoring and forecasting tools.

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