scholarly journals Hypoxia triggers collective aerotactic migration in Dictyostelium discoideum

2020 ◽  
Author(s):  
O. Cochet-Escartin ◽  
M. Demircigil ◽  
S. Hirose ◽  
B. Allais ◽  
P. Gonzalo ◽  
...  
Keyword(s):  
Dictyostelium Discoideum ◽  
Cell Communication ◽  
Quantitative Agreement ◽  
Cellular Potts Model ◽  
Detection Mechanism ◽  
Cell Behaviors ◽  
Dense Ring ◽  
Efficient Detection ◽  
Technological Developments ◽  
A Cell

AbstractIt is well known that eukaryotic cells can sense oxygen (O2) and adapt their metabolism accordingly. It is less known that they can also move towards regions of higher oxygen level (aerotaxis). Using a self-generated hypoxic assay, we show that the social amoeba Dictyostelium discoideum displays a spectacular aerotactic behavior. When a cell colony is covered by a coverglass, cells quickly consume the available O2 and the ones close to the periphery move directionally outward forming a dense ring keeping a constant speed and density. To confirm that O2 is the main molecular player in this seemingly collective process, we combined two technological developments, porphyrin based O2 sensing films and microfluidic O2 gradient generators. We showed that Dictyostelium cells exhibit aerotactic and aerokinetic (increased speed at low O2) response in an extremely low range of O2 concentration (0-1.5%) indicative of a very efficient detection mechanism. The various cell behaviors under self-generated or imposed O2 gradients were modeled with a very satisfactory quantitative agreement using an in silico cellular Potts model built on experimental observations. This computational model was complemented with a parsimonious ‘Go or Grow’ partial differential equation (PDE) model. In both models, we found that the collective migration of a dense ring can be explained by the interplay between cell division and the modulation of aerotaxis, without the need for cell-cell communication.

scholarly journals Hypoxia triggers collective aerotactic migration in Dictyostelium discoideum

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Olivier Cochet-Escartin ◽  
Mete Demircigil ◽  
Satomi Hirose ◽  
Blandine Allais ◽  
Philippe Gonzalo ◽  
...  
Keyword(s):  
Dictyostelium Discoideum ◽  
Cellular Potts Model ◽  
Detection Mechanism ◽  
Cell Behaviors ◽  
Dense Ring ◽  
Pde Model ◽  
Efficient Detection ◽  
Technological Developments ◽  
A Cell ◽  
Collective Process

Using a self-generated hypoxic assay, we show that the amoeba Dictyostelium discoideum displays a remarkable collective aerotactic behavior. When a cell colony is covered, cells quickly consume the available oxygen (O2) and form a dense ring moving outwards at constant speed and density. To decipher this collective process, we combined two technological developments: porphyrin-based O2 -sensing films and microfluidic O2 gradient generators. We showed that Dictyostelium cells exhibit aerotactic and aerokinetic response in a low range of O2 concentration indicative of a very efficient detection mechanism. Cell behaviors under self-generated or imposed O2 gradients were modeled using an in silico cellular Potts model built on experimental observations. This computational model was complemented with a parsimonious ‘Go or Grow’ partial differential equation (PDE) model. In both models, we found that the collective migration of a dense ring can be explained by the interplay between cell division and the modulation of aerotaxis.

scholarly journals NH2-terminal acetylation of Dictyostelium discoideum actin in a cell-free protein-synthesizing system.

1981 ◽  
Vol 256 (15) ◽  
pp. 8149-8155 ◽  
Author(s):  
P. Rubenstein ◽  
P. Smith ◽  
J. Deuchler ◽  
K. Redman
Keyword(s):  
Dictyostelium Discoideum ◽  
Free Protein ◽  
A Cell

scholarly journals Analysis of the RNA content of the exosomes derived from blood serum and urine and its potential as biomarkers

2014 ◽  
Vol 369 (1652) ◽  
pp. 20130502 ◽  
Author(s):  
Mu Li ◽  
Emily Zeringer ◽  
Timothy Barta ◽  
Jeoffrey Schageman ◽  
Angie Cheng ◽  
...  
Keyword(s):  
Blood Serum ◽  
Cell Communication ◽  
Cell Culture Model ◽  
Culture Model ◽  
Wide Range ◽  
Abnormal Cells ◽  
A Cell ◽  
Invasive Diagnostics ◽  
Serum And Urine

Exosomes are tiny vesicles (30–150 nm) constantly secreted by all healthy and abnormal cells, and found in abundance in all body fluids. These vesicles, loaded with unique RNA and protein cargo, have a wide range of biological functions, including cell-to-cell communication and signalling. As such, exosomes hold tremendous potential as biomarkers and could lead to the development of minimally invasive diagnostics and next generation therapies within the next few years. Here, we describe the strategies for isolation of exosomes from human blood serum and urine, characterization of their RNA cargo by sequencing, and present the initial data on exosome labelling and uptake tracing in a cell culture model. The value of exosomes for clinical applications is discussed with an emphasis on their potential for diagnosing and treating neurodegenerative diseases and brain cancer.

Microglia extracellular vesicles: focus on molecular composition and biological function

2021 ◽  
Vol 49 (4) ◽  
pp. 1779-1790 ◽  
Author(s):  
Lorenzo Ceccarelli ◽  
Chiara Giacomelli ◽  
Laura Marchetti ◽  
Claudia Martini
Keyword(s):  
Extracellular Vesicles ◽  
Molecular Mechanisms ◽  
Biological Function ◽  
Biological Effects ◽  
Genetic Material ◽  
Cell Communication ◽  
Molecular Composition ◽  
Cargo Proteins ◽  
A Cell ◽  
The Central Nervous System

Extracellular vesicles (EVs) are a heterogeneous family of cell-derived lipid bounded vesicles comprising exosomes and microvesicles. They are potentially produced by all types of cells and are used as a cell-to-cell communication method that allows protein, lipid, and genetic material exchange. Microglia cells produce a large number of EVs both in resting and activated conditions, in the latter case changing their production and related biological effects. Several actions of microglia in the central nervous system are ascribed to EVs, but the molecular mechanisms by which each effect occurs are still largely unknown. Conflicting functions have been ascribed to microglia-derived EVs starting from the neuronal support and ending with the propagation of inflammation and neurodegeneration, confirming the crucial role of these organelles in tuning brain homeostasis. Despite the increasing number of studies reported on microglia-EVs, there is also a lot of fragmentation in the knowledge on the mechanism at the basis of their production and modification of their cargo. In this review, a collection of literature data about the surface and cargo proteins and lipids as well as the miRNA content of EVs produced by microglial cells has been reported. A special highlight was given to the works in which the EV molecular composition is linked to a precise biological function.

scholarly journals Medicinal Leech CNS as a Model for Exosome Studies in the Crosstalk between Microglia and Neurons

2018 ◽  
Vol 19 (12) ◽  
pp. 4124 ◽  
Author(s):  
Antonella Raffo-Romero ◽  
Tanina Arab ◽  
Issa Al-Amri ◽  
Francoise Le Marrec-Croq ◽  
Christelle Van Camp ◽  
...  
Keyword(s):  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Ex Vivo ◽  
Present Report ◽  
Primary Cultures ◽  
Cell Communication ◽  
Medicinal Leech ◽  
Neuronal Cultures ◽  
Primary Neuronal Cultures ◽  
A Cell

In healthy or pathological brains, the neuroinflammatory state is supported by a strong communication involving microglia and neurons. Recent studies indicate that extracellular vesicles (EVs), including exosomes and microvesicles, play a key role in the physiological interactions between cells allowing central nervous system (CNS) development and/or integrity. The present report used medicinal leech CNS to investigate microglia/neuron crosstalk from ex vivo approaches as well as primary cultures. The results demonstrated a large production of exosomes from microglia. Their incubation to primary neuronal cultures showed a strong interaction with neurites. In addition, neurite outgrowth assays demonstrated microglia exosomes to exhibit significant neurotrophic activities using at least a Transforming Growth Factor beta (TGF-β) family member, called nGDF (nervous Growth/Differentiation Factor). Of interest, the results also showed an EV-mediated dialog between leech microglia and rat cells highlighting this communication to be more a matter of molecules than of species. Taken together, the present report brings a new insight into the microglia/neuron crosstalk in CNS and would help deciphering the molecular evolution of such a cell communication in brain.

scholarly journals Mapping of a cell-binding domain in the cell adhesion molecule gp80 of Dictyostelium discoideum.

1988 ◽  
Vol 107 (5) ◽  
pp. 1835-1843 ◽  
Author(s):  
R K Kamboj ◽  
L M Wong ◽  
T Y Lam ◽  
C H Siu
Keyword(s):  
Cell Adhesion ◽  
Dictyostelium Discoideum ◽  
Fusion Proteins ◽  
Binding Activity ◽  
Binding Domain ◽  
Globular Domain ◽  
Cell Binding ◽  
Homophilic Interaction ◽  
A Cell ◽  
Cell Binding Domain

At the aggregation stage of Dictyostelium discoideum development, a cell surface glycoprotein of Mr 80,000 (gp80) has been found to mediate the EDTA-resistant type of cell-cell adhesion via homophilic interaction (Siu, C.-H., A. Cho, and A. H. C. Choi. 1987. J. Cell Biol. 105:2523-2533). To investigate the structure-function relationships of gp80, we have isolated full length cDNA clones for gp80 and determined the DNA sequence. The deduced structure of gp80 showed three major domains. An amino-terminal globular domain composed of the bulk of the protein is supported by a short stalk region, which is followed by a membrane anchor at the carboxy terminus. Structural analysis suggested that the cell-binding domain of gp80 resides within the globular domain near the amino terminus. To investigate the relationship of the cell-binding activity to this region of the polypeptide, three protein A/gp80 (PA80) gene fusions were constructed using the expression vector pRIT2T. These PA80 fusion proteins were assayed for their ability to bind to aggregation stage cells. Binding of 125I-labeled fusion proteins PA80I (containing the Val123 to Ile514 fragment of gp80) and PA80II (Val123 to Ala258) was dosage dependent and could be inhibited by precoating cells with the cell cohesion-blocking mAb 80L5C4. On the other hand, there was no appreciable binding of PA80III (Ile174 to Ile514) to cells. Reassociation of cells was significantly inhibited in the presence of PA80I or PA80II. In addition, 125I-labeled PA80II exhibited homophilic interaction with immobilized PA80I, PA80II, or gp80. The results of these studies lead to the mapping of a cell-binding domain in the region between Val123 and Leu173 of gp80 and provide direct evidence that the cell-binding activity of gp80 resides in the protein moiety.

scholarly journals Controlled Construction of Stable Network Structure Composed of Honeycomb-Shaped Microhydrogels

Life ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 38 ◽  
Author(s):  
Masayuki Hayakawa ◽  
Satoshi Umeyama ◽  
Ken Nagai ◽  
Hiroaki Onoe ◽  
Masahiro Takinoue
Keyword(s):  
Cell Communication ◽  
Model Systems ◽  
Stable Component ◽  
Photosensitive Polymer ◽  
A Cell ◽  
External Stimuli ◽  
Structural Instabilities ◽  
Insight Into ◽  
Stable Network ◽  
Microfluidic Technique

Recently, the construction of models for multicellular systems such as tissues has been attracting great interest. These model systems are expected to reproduce a cell communication network and provide insight into complicated functions in living systems./Such network structures have mainly been modelled using a droplet and a vesicle. However, in the droplet and vesicle network, there are difficulties attributed to structural instabilities due to external stimuli and perturbations. Thus, the fabrication of a network composed of a stable component such as hydrogel is desired. In this article, the construction of a stable network composed of honeycomb-shaped microhydrogels is described. We produced the microhydrogel network using a centrifugal microfluidic technique and a photosensitive polymer. In the network, densely packed honeycomb-shaped microhydrogels were observed. Additionally, we successfully controlled the degree of packing of microhydrogels in the network by changing the centrifugal force. We believe that our stable network will contribute to the study of cell communication in multicellular systems.

A centrosome-associated antibody from Drosophila melanogaster reveals a new microtubule-dependent structure in the equatorial zone of Parascaris univalens embryos

1993 ◽  
Vol 106 (3) ◽  
pp. 719-730
Author(s):  
M. Jimenez ◽  
C. Goday
Keyword(s):  
Drosophila Melanogaster ◽  
Cytochalasin B ◽  
Cell Communication ◽  
Equatorial Zone ◽  
Contractile Ring ◽  
Daughter Cells ◽  
Ring Assembly ◽  
Single Body ◽  
A Cell ◽  
Cycle Dependent

The distribution of antigens to two antibodies (Bx63 and Rb188) that associate to Drosophila melanogaster centrosomes has been investigated in the nematode Parascaris. By western blot analysis both antibodies identify in Parascaris polypeptides of the same molecular mass as in Drosophila (Rb188 a 185 kDa antigen and Bx63 185 kDa and 66 kDa antigens). By immunocytochemistry we show that the centrosomes of Parascaris contain the 185 kDa antigen recognized by polyclonal Rb188 and monoclonal Bx63 antibodies. In addition, Bx63 reveals cytoplasmic midzone structures, not found in Drosophila, that display a cell cycle-dependent organization in embryos. These structures, which most probably contain the 66 kDa antigen revealed by Bx63, appear at the onset of anaphase as fibrillar-like structures that during anaphase form a ring-like structure encircling the equatorial plane of the blastomere. Before furrowing, the antigen participates in the formation of the midbody and associates with convergent polar microtubules. After blastomere division, Bx63 signal persists as a single body between the daughter cells. The analysis of chilled and nocodazole-treated embryos suggests that the localization of the midzone Bx63 antigen is dependent on non-kinetochore microtubules. Inhibition of furrowing by cytochalasin B shows that the antigen persists after the disassembly of microfilaments. Cytological observations of contractile ring and Bx63 ring assembly indicate that both structures do not simultaneously colocalize at the equatorial zone. The data suggest a spindle-dependent distribution of the Bx63 antigen during cytokinesis. We discuss the participation of this antigen in the organization of the midbody before furrowing, and consider the possible relevance of the midbody with respect to cell to cell communication during early development in nematodes.

Knowledge Disclosed in Patent Documents as Source of Information to Address Emergencies: A Strategy to Achieve Technological Developments Addressing COVID-19

2021 ◽  
Vol 15 ◽  
Author(s):  
Tatiana Duque Martins ◽  
Diéricon Sousa Cordeiro
Keyword(s):  
Emergency Situation ◽  
Daily Basis ◽  
Accurate Information ◽  
Technological Information ◽  
The World ◽  
Technological Developments ◽  
A Cell ◽  
Patent Documents ◽  
High Level ◽  
Source Of Information

Background: Face COVID-19 pandemic, a need for accurate information on SARS-CoV-2 virus is urgent and scientific reports have been published on daily basis to enable effective technologies to fight the disease progression. However, at the first moments of Pandemic, no information on the matter was known and technologies to fight the Pandemic were not readily available. However, searches in patent databases, if strategically designed, can offer quick responses to new pandemics. Objective: Aiming to provide existing information in patent documents useful to develop technologies addressing COVID-19, considering the emergency situation the world was facing and the knowledge of COVID-19 available until April, 2020, this work presents an analysis of the main characteristics of the technological information in patent documents worldwide, related to coronaviruses and the severe acute respiratory syndrome (SARS). Method: Regions of concentration of such technologies, the number of available documents and their technological fields are disclosed in three approaches: 1) a wide search, retrieving technologies on SARS or coronaviruses; 2) a targeted search, retrieving documents additionally referring to Angiotensin converting enzyme (ACE2), which is used by SARS-CoV-2 to enter a cell and 3) a punctual search, which retrieved patents disclosing aspects related to SARS-CoV-2 available at that time. Results and Conclusion: Results evidence the high-level technology involved in these developments and a monopoly tendency of such technologies, evidencing that it is possible to find answers to new problems in patent documents.

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