Self-sustained Marangoni Flows Driven by Chemical Reactions

10.26434/chemrxiv.14535930 ◽

2021 ◽

Author(s):

Anne-Déborah C. Nguindjel ◽

Peter A. Korevaar

Keyword(s):

Chemical Reactions ◽

Self Assembly ◽

Marangoni Flow ◽

Chemical Systems ◽

Fuel Delivery ◽

Threshold Conditions ◽

The Impact ◽

Assembly Pathways ◽

Equilibrium Chemical ◽

Photoacid Generator

Out-of-equilibrium chemical systems, comprising reaction networks and molecular self-assembly pathways, rely on the delivery of reagents. Rather than via external flow, diffusion or convection, we aim at self-sustained reagent delivery. Therefore, we explore how the coupling of Marangoni flow with chemical reactions can generate self-sustained flows, driven by said chemical reactions, and – in turn – sustained by the delivery of reagents for this reaction. We combine a photoacid generator with a pH-responsive surfactant, such that local UV exposure decreases the pH, increases the surface tension and triggers the emergence of a Marangoni flow. We study the impact of reagent concentrations and identify threshold conditions at which flow can emerge. Surprisingly, we unraveled an antagonistic influence of the reagents on key features of the flow such as interfacial velocity and duration, and rationalize these findings via a kinetic model. Our study displays the potential of reaction-driven flow to establish autonomous control in fuel delivery of out-of-equilibrium systems.

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Hydrophobic domain flexibility enables morphology control of amphiphilic systems in aqueous media

Chemical Communications ◽

10.1039/d0cc06173e ◽

2020 ◽

Vol 56 (89) ◽

pp. 13808-13811

Author(s):

Ingo Helmers ◽

Nils Bäumer ◽

Gustavo Fernández

Keyword(s):

Self Assembly ◽

Aqueous Media ◽

Morphology Control ◽

The Self ◽

Hydrophobic Domain ◽

Aggregate Morphology ◽

The Impact ◽

Assembly Pathways

In this work, we unravel the impact of hydrophobic domain flexibility on the self-assembly pathways and aggregate morphology of amphiphilic systems in aqueous media.

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Biotransformation of Coumarins by Filamentous Fungi: An Alternative Way for Achievement of Bioactive Analogs

Mini-Reviews in Organic Chemistry ◽

10.2174/1570193x15666180803094216 ◽

2019 ◽

Vol 16 (6) ◽

pp. 568-577 ◽

Cited By ~ 1

Author(s):

Jainara Santos do Nascimento ◽

João Carlos Silva Conceição ◽

Eliane de Oliveira Silva

Keyword(s):

Filamentous Fungi ◽

Chemical Reactions ◽

Biological Activities ◽

Chemical Transformations ◽

Chemical Structures ◽

Pattern Structures ◽

Pharmacological Interest ◽

Aspergillus Sp ◽

The Impact ◽

Related Compounds

Coumarins are natural 1,2-benzopyrones, present in remarkable amounts as secondary metabolites in edible and medicinal plants. The low yield in the coumarins isolation from natural sources, along with the difficulties faced by the total synthesis, make them attractive for biotechnological studies. The current literature contains several reports on the biotransformation of coumarins by fungi, which can generate chemical analogs with high selectivity, using mild and eco-friendly conditions. Prompted by the enormous pharmacological interest in the coumarin-related compounds, their alimentary and chemical applications, this review covers the biotransformation of coumarins by filamentous fungi. The chemical structures of the analogs were presented and compared with those from the pattern structures. The main chemical reactions catalyzed the insertion of functional groups, and the impact on the biological activities caused by the chemical transformations were discussed. Several chemical reactions can be catalyzed by filamentous fungi in the coumarin scores, mainly lactone ring opening, C3-C4 reduction and hydroxylation. Chunninghamella sp. and Aspergillus sp. are the most common fungi used in these transformations. Concerning the substrates, the biotransformation of pyranocoumarins is a rarer process. Sometimes, the bioactivities were improved by the chemical modifications and coincidences with the mammalian metabolism were pointed out.

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‘Whole Organism’, Systems Biology, and Top-Down Criteria for Evaluating Scenarios for the Origin of Life

Life ◽

10.3390/life11070690 ◽

2021 ◽

Vol 11 (7) ◽

pp. 690

Author(s):

Clifford F. Brunk ◽

Charles R. Marshall

Keyword(s):

Origin Of Life ◽

Top Down ◽

Chemical Systems ◽

Biochemical Pathways ◽

The Origin Of Life ◽

Energy And Material Flows ◽

Complex Scenario ◽

Life On Earth ◽

Physical Laws ◽

Equilibrium Chemical

While most advances in the study of the origin of life on Earth (OoLoE) are piecemeal, tested against the laws of chemistry and physics, ultimately the goal is to develop an overall scenario for life’s origin(s). However, the dimensionality of non-equilibrium chemical systems, from the range of possible boundary conditions and chemical interactions, renders the application of chemical and physical laws difficult. Here we outline a set of simple criteria for evaluating OoLoE scenarios. These include the need for containment, steady energy and material flows, and structured spatial heterogeneity from the outset. The Principle of Continuity, the fact that all life today was derived from first life, suggests favoring scenarios with fewer non-analog (not seen in life today) to analog (seen in life today) transitions in the inferred first biochemical pathways. Top-down data also indicate that a complex metabolism predated ribozymes and enzymes, and that full cellular autonomy and motility occurred post-LUCA. Using these criteria, we find the alkaline hydrothermal vent microchamber complex scenario with a late evolving exploitation of the natural occurring pH (or Na+ gradient) by ATP synthase the most compelling. However, there are as yet so many unknowns, we also advocate for the continued development of as many plausible scenarios as possible.

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Virus-Like Particles Produced Using the Brome Mosaic Virus Recombinant Capsid Protein Expressed in a Bacterial System

International Journal of Molecular Sciences ◽

10.3390/ijms22063098 ◽

2021 ◽

Vol 22 (6) ◽

pp. 3098

Author(s):

Aleksander Strugała ◽

Jakub Jagielski ◽

Karol Kamel ◽

Grzegorz Nowaczyk ◽

Marcin Radom ◽

...

Keyword(s):

Ionic Strength ◽

Mosaic Virus ◽

Capsid Protein ◽

Self Assembly ◽

Environmental Changes ◽

Expression System ◽

Brome Mosaic Virus ◽

Virus Like Particles ◽

Assembly Principles ◽

The Impact

Virus-like particles (VLPs), due to their nanoscale dimensions, presence of interior cavities, self-organization abilities and responsiveness to environmental changes, are of interest in the field of nanotechnology. Nevertheless, comprehensive knowledge of VLP self-assembly principles is incomplete. VLP formation is governed by two types of interactions: protein–cargo and protein–protein. These interactions can be modulated by the physicochemical properties of the surroundings. Here, we used brome mosaic virus (BMV) capsid protein produced in an E. coli expression system to study the impact of ionic strength, pH and encapsulated cargo on the assembly of VLPs and their features. We showed that empty VLP assembly strongly depends on pH whereas ionic strength of the buffer plays secondary but significant role. Comparison of VLPs containing tRNA and polystyrene sulfonic acid (PSS) revealed that the structured tRNA profoundly increases VLPs stability. We also designed and produced mutated BMV capsid proteins that formed VLPs showing altered diameters and stability compared to VLPs composed of unmodified proteins. We also observed that VLPs containing unstructured polyelectrolyte (PSS) adopt compact but not necessarily more stable structures. Thus, our methodology of VLP production allows for obtaining different VLP variants and their adjustment to the incorporated cargo.

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Autocatalytic and oscillatory reaction networks that form guanidines and products of their cyclization

Nature Communications ◽

10.1038/s41467-021-23206-9 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Alexander I. Novichkov ◽

Anton I. Hanopolskyi ◽

Xiaoming Miao ◽

Linda J. W. Shimon ◽

Yael Diskin-Posner ◽

...

Keyword(s):

Chemical Cues ◽

Native Chemical Ligation ◽

Reaction Networks ◽

Oscillatory Reaction ◽

Experimental Conditions ◽

Chemical Ligation ◽

Chemical Systems ◽

Life On Earth ◽

Emergence Of Life ◽

Equilibrium Chemical

AbstractAutocatalytic and oscillatory networks of organic reactions are important for designing life-inspired materials and for better understanding the emergence of life on Earth; however, the diversity of the chemistries of these reactions is limited. In this work, we present the thiol-assisted formation of guanidines, which has a mechanism analogous to that of native chemical ligation. Using this reaction, we designed autocatalytic and oscillatory reaction networks that form substituted guanidines from thiouronium salts. The thiouronium salt-based oscillator show good stability of oscillations within a broad range of experimental conditions. By using nitrile-containing starting materials, we constructed an oscillator where the concentration of a bicyclic derivative of dihydropyrimidine oscillates. Moreover, the mixed thioester and thiouronium salt-based oscillator show unique responsiveness to chemical cues. The reactions developed in this work expand our toolbox for designing out-of-equilibrium chemical systems and link autocatalytic and oscillatory chemistry to the synthesis of guanidinium derivatives and the products of their transformations including analogs of nucleobases.

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