scholarly journals Synthetic Cell as a Platform for Understanding Membrane-Membrane Interactions

Membranes ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 912
Author(s):  
Bineet Sharma ◽  
Hossein Moghimianavval ◽  
Sung-Won Hwang ◽  
Allen P. Liu
Keyword(s):  
Membrane Fusion ◽  
Intercellular Communication ◽  
Lipid Vesicles ◽  
Bilayer Membrane ◽  
Future Research ◽  
Membrane Interactions ◽  
Protein Insertion ◽  
Synthetic Cell ◽  
Challenges And Opportunities ◽  
Synthetic Cells

In the pursuit of understanding life, model membranes made of phospholipids were envisaged decades ago as a platform for the bottom-up study of biological processes. Micron-sized lipid vesicles have gained great acceptance as their bilayer membrane resembles the natural cell membrane. Important biological events involving membranes, such as membrane protein insertion, membrane fusion, and intercellular communication, will be highlighted in this review with recent research updates. We will first review different lipid bilayer platforms used for incorporation of integral membrane proteins and challenges associated with their functional reconstitution. We next discuss different methods for reconstitution of membrane fusion and compare their fusion efficiency. Lastly, we will highlight the importance and challenges of intercellular communication between synthetic cells and synthetic cells-to-natural cells. We will summarize the review by highlighting the challenges and opportunities associated with studying membrane–membrane interactions and possible future research directions.

In search of a novel chassis material for synthetic cells: emergence of synthetic peptide compartment

Soft Matter ◽  
2020 ◽  
Vol 16 (48) ◽  
pp. 10769-10780
Author(s):  
Bineet Sharma ◽  
Yutao Ma ◽  
Andrew L. Ferguson ◽  
Allen P. Liu
Keyword(s):  
Synthetic Peptide ◽  
Cell Model ◽  
Lipid Vesicles ◽  
Synthetic Cell ◽  
Synthetic Cells

Giant lipid vesicles have been used extensively as a synthetic cell model to recapitulate various life-like processes. In recent years, peptide vesicles are gaining attention as an alternative chassis material.

scholarly journals Facile Formation of Giant Elastin-like Polypeptide Vesicles as Synthetic Cells

2021 ◽  
Author(s):  
Bineet Sharma ◽  
Yutao Ma ◽  
Andrew Ferguson ◽  
Allen Liu
Keyword(s):  
Host Cell ◽  
Lipid Vesicles ◽  
Free Expression ◽  
Polymer Conjugates ◽  
Protein Polymer ◽  
Synthetic Cell ◽  
Synthetic Cells ◽  
Transfer Method ◽  
Physical And Chemical ◽  
Natural Cell

Creating a suitable compartment for synthetic cells has led the exploration of different cell chassis materials from phospholipids to polymer to protein-polymer conjugates. Currently, the majority of cell-like compartments are made of lipid molecules as the resulting membrane resembles that of a natural cell. However, cell-sized lipid vesicles are prone to physical and chemical stresses and can be unstable in hosting biochemical reactions within. Recently, peptide vesicles that are more robust and stable were developed as a new chassis material for synthetic cells. Here we demonstrate the facile and robust generation of giant peptide vesicles made of elastin-like polypeptides (ELPs) by using an emulsion transfer method. We show that these peptide vesicles can stably encapsulate molecules and can host cell-free expression reactions. We also demonstrate membrane incorporation of another amphiphilic ELP into existing peptide vesicles. Since ELPs are genetically encoded, the approaches presented here provide exciting opportunities to engineer synthetic cell membranes.

Experiments on and Numerical Modeling of the Capture and Concentration of Transcription-Translation Machinery inside Vesicles

2015 ◽  
Vol 21 (4) ◽  
pp. 445-463 ◽  
Author(s):  
Fabio Mavelli ◽  
Pasquale Stano
Keyword(s):  
Lipid Vesicles ◽  
Future Research ◽  
Partition Functions ◽  
Research Directions ◽  
Open Questions ◽  
Synthetic Cells ◽  
Measurable Rate ◽  
Future Research Directions ◽  
Minimal Cells ◽  
Fundamental Physical

Synthetic or semi-synthetic minimal cells are those cell-like artificial compartments that are based on the encapsulation of molecules inside lipid vesicles (liposomes). Synthetic cells are currently used as primitive cell models and are very promising tools for future biotechnology. Despite the recent experimental advancements and sophistication reached in this field, the complete elucidation of many fundamental physical aspects still poses experimental and theoretical challenges. The interplay between solute capture and vesicle formation is one of the most intriguing ones. In a series of studies, we have reported that when vesicles spontaneously form in a dilute solution of proteins, ribosomes, or ribo-peptidic complexes, then, contrary to statistical predictions, it is possible to find a small fraction of liposomes (<1%) that contain a very large number of solutes, so that their local (intravesicular) concentrations largely exceed the expected value. More recently, we have demonstrated that this effect (spontaneous crowding) operates also on multimolecular mixtures, and can drive the synthesis of proteins inside vesicles, whereas the same reaction does not proceed at a measurable rate in the external bulk phase. Here we firstly introduce and discuss these already published observations. Then, we present a computational investigation of the encapsulation of transcription-translation (TX-TL) machinery inside vesicles, based on a minimal protein synthesis model and on different solute partition functions. Results show that experimental data are compatible with an entrapment model that follows a power law rather than a Gaussian distribution. The results are discussed from the viewpoint of origin of life, highlighting open questions and possible future research directions.

scholarly journals Facile Formation of Giant Elastin-like Polypeptide Vesicles as Synthetic Cells

2021 ◽  
Author(s):  
Bineet Sharma ◽  
Yutao Ma ◽  
Andrew Ferguson ◽  
Allen Liu
Keyword(s):  
Host Cell ◽  
Lipid Vesicles ◽  
Free Expression ◽  
Polymer Conjugates ◽  
Protein Polymer ◽  
Synthetic Cell ◽  
Synthetic Cells ◽  
Transfer Method ◽  
Physical And Chemical ◽  
Natural Cell

Creating a suitable compartment for synthetic cells has led the exploration of different cell chassis materials from phospholipids to polymer to protein-polymer conjugates. Currently, the majority of cell-like compartments are made of lipid molecules as the resulting membrane resembles that of a natural cell. However, cell-sized lipid vesicles are prone to physical and chemical stresses and can be unstable in hosting biochemical reactions within. Recently, peptide vesicles that are more robust and stable were developed as a new chassis material for synthetic cells. Here we demonstrate the facile and robust generation of giant peptide vesicles made of elastin-like polypeptides (ELPs) by using an emulsion transfer method. We show that these peptide vesicles can stably encapsulate molecules and can host cell-free expression reactions. We also demonstrate membrane incorporation of another amphiphilic ELP into existing peptide vesicles. Since ELPs are genetically encoded, the approaches presented here provide exciting opportunities to engineer synthetic cell membranes.

Trophoblast Cell Membrane Interactions at Implantation

1970 ◽  
Vol 28 ◽  
pp. 310-311
Author(s):  
A. C. Enders
Keyword(s):  
Epithelial Cells ◽  
Cell Membrane ◽  
Membrane Fusion ◽  
Trophoblast Cell ◽  
Membrane Interactions ◽  
Uterine Epithelial Cells ◽  
Functional Complex ◽  
Cytotrophoblast Cells ◽  
Complex Relationships ◽  
Syncytial Trophoblast

The alteration in membrane relationships seen at implantation include 1) interaction between cytotrophoblast cells to form syncytial trophoblast and addition to the syncytium by subsequent fusion of cytotrophoblast cells, 2) formation of a wide variety of functional complex relationships by trophoblast with uterine epithelial cells in the process of invasion of the endometrium, and 3) in the case of the rabbit, fusion of some uterine epithelial cells with the trophoblast.Formation of syncytium is apparently a membrane fusion phenomenon in which rapid confluence of cytoplasm often results in isolation of residual membrane within masses of syncytial trophoblast. Often the last areas of membrane to disappear are those including a desmosome where the cell membranes are apparently held apart from fusion.

Challenges and Opportunities for Neuroimaging in Young Patients with Traumatic Brain Injury: a Coordinated Effort towards Advancing Discovery from the ENIGMA Pediatric Moderate/Severe TBI Group

2019 ◽  
Author(s):  
Emily L. Dennis ◽  
Karen Caeyenberghs ◽  
Robert F. Asarnow ◽  
Talin Babikian ◽  
Brenda Bartnik-Olson ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Meta Analysis ◽  
Young Patients ◽  
Future Research ◽  
Childhood And Adolescence ◽  
Developmental Issues ◽  
Challenges And Opportunities ◽  
Severe Tbi ◽  
Advance Research

Traumatic brain injury (TBI) is a major cause of death and disability in children in both developed and developing nations. Children and adolescents suffer from TBI at a higher rate than the general population; however, research in this population lags behind research in adults. This may be due, in part, to the smaller number of investigators engaged in research with this population and may also be related to changes in safety laws and clinical practice that have altered length of hospital stays, treatment, and access to this population. Specific developmental issues also warrant attention in studies of children, and the ever-changing context of childhood and adolescence may require larger sample sizes than are commonly available to adequately address remaining questions related to TBI. The ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) Pediatric Moderate-Severe TBI (msTBI) group aims to advance research in this area through global collaborative meta-analysis. In this paper we discuss important challenges in pediatric TBI research and opportunities that we believe the ENIGMA Pediatric msTBI group can provide to address them. We conclude with recommendations for future research in this field of study.

Substrate−Membrane Interactions:  Mechanisms for Imposing Patterns on a Fluid Bilayer Membrane

Langmuir ◽  
1998 ◽  
Vol 14 (12) ◽  
pp. 3347-3350 ◽  
Author(s):  
Jay T. Groves ◽  
Nick Ulman ◽  
Paul S. Cremer ◽  
Steven G. Boxer
Keyword(s):  
Bilayer Membrane ◽  
Membrane Interactions

Bilayer Membrane Bending Stiffness by Tether Formation From Mixed PC-PS Lipid Vesicles

1990 ◽  
Vol 112 (3) ◽  
pp. 235-240 ◽  
Author(s):  
J. Song ◽  
R. E. Waugh
Keyword(s):  
Present Report ◽  
Membrane Surface ◽  
Lipid Vesicles ◽  
Phosphatidyl Serine ◽  
Bilayer Membrane ◽  
Bending Stiffness ◽  
New Approach ◽  
Lipid Mixtures ◽  
Membrane Bending ◽  
Membrane Surface Charge

Recently, a new approach to measure the bending stiffness (curvature elastic modulus) of lipid bilayer membrane was developed (Biophys. J., Vol. 55; pp. 509–517, 1989). The method involves the formation of cylindrical membrane strands (tethers) from bilayer vesicles. The bending stiffness (B) can be calculated from measurements of the tether radius (Rt) as a function of the axial force (f) on the tether: B =f·Rt/2π. In the present report, we apply this method to determine the bending stiffness of bilayer membranes composed of mixtures of SOPC (1-stearoyl-2-oleoyl phosphatidyl choline) and POPS (1-palmitoyl-2-oleoyl phosphatidyl serine). Three different mixtures were tested: pure SOPC, SOPC plus 2 percent (mol/mol) POPS, and SOPC plus 16 percent POPS. The bending stiffness determined for these three different lipid mixtures were not significantly different (1.6–1.8×10-12 ergs). Because POPS carries a net negative charge, these results indicate that changes in the density of the membrane surface charge have no effect on the intrinsic rigidity of the membrane. The values we obtain are consistent with published values for the bending stiffness of other membranes determined by different methods. Measurements of the aspiration pressure, the tether radius and the tether force were used to verify a theoretical relationship among these quantities at equilibrium. The ratio of the theoretical force to the measured force was 1.12 ± 0.17.

scholarly journals Crowdfunding: Motives, Definitions, Typology and Ethical Challenges

2017 ◽  
Vol 7 (2) ◽  
Author(s):  
Mokter Hossain ◽  
Gospel Onyema Oparaocha
Keyword(s):  
Final Section ◽  
Theoretical Foundation ◽  
Ethical Issues ◽  
Future Research ◽  
Ethical Challenges ◽  
Alternative Source ◽  
Significant Interest ◽  
Challenges And Opportunities ◽  
Conceptual Paper

AbstractCrowdfunding is an emerging phenomenon that has attracted significant interest from scholars and practitioners alike, mainly due to its appeal as an alternative source of funding. As crowdfunding has grown exponentially, so have the associated challenges and opportunities. In this conceptual paper, we define crowdfunding; discuss its characteristics, related terminologies, key elements and ethical issues. We also propose a typology for crowdfunding and indicate various issues associated with it. The final section includes the implications of this study and suggestions for future research. This paper aims to inspire a scholarly debate and further develop the theoretical foundation of the crowdfunding literature. This may also prompt practitioners to take note of the emerging concerns as the crowdfunding phenomenon is transforming from a marginal to a mainstream discipline.

The English Language Learning Progressions (ELLP): Challenge or opportunity?

2020 ◽  
Vol 16 ◽  
pp. 21-37
Author(s):  
Judith Anthony
Keyword(s):  
Language Learning ◽  
English Language ◽  
Future Research ◽  
English Language Learning ◽  
Learning Progressions ◽  
Ministry Of Education ◽  
Critical Policy Analysis ◽  
Challenges And Opportunities ◽  
Key Issues ◽  
Critical Policy

This article provides an overview and critical analysis of The English Language Learning Progressions (ELLP) (Ministry of Education, 2008). Identifying main themes through critical policy analysis, this review seeks to place ELLP in context through a comparison with The English Language Learning Framework: Draft (Ministry of Education, 2005) and English Language Learning Progressions (ELLP ) Pathway Years 1–8 (Ministry of Education, 2020a). Within this review, the structure of ELLP is explored along with key ideas and claims. It is argued that there are both challenges and opportunities in ELLP. Finally, the key issues are summarised and suggestions are made for future research.

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