| 1. |
- Romanelli, F, et al.
(författare)
-
Overview of the JET results
- 2011
-
Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 51:9
-
Tidskriftsartikel (refereegranskat)abstract
- Since the last IAEA Conference JET has been in operation for one year with a programmatic focus on the qualification of ITER operating scenarios, the consolidation of ITER design choices and preparation for plasma operation with the ITER-like wall presently being installed in JET. Good progress has been achieved, including stationary ELMy H-mode operation at 4.5 MA. The high confinement hybrid scenario has been extended to high triangularity, lower ρ*and to pulse lengths comparable to the resistive time. The steady-state scenario has also been extended to lower ρ*and ν*and optimized to simultaneously achieve, under stationary conditions, ITER-like values of all other relevant normalized parameters. A dedicated helium campaign has allowed key aspects of plasma control and H-mode operation for the ITER non-activated phase to be evaluated. Effective sawtooth control by fast ions has been demonstrated with3He minority ICRH, a scenario with negligible minority current drive. Edge localized mode (ELM) control studies using external n = 1 and n = 2 perturbation fields have found a resonance effect in ELM frequency for specific q95values. Complete ELM suppression has, however, not been observed, even with an edge Chirikov parameter larger than 1. Pellet ELM pacing has been demonstrated and the minimum pellet size needed to trigger an ELM has been estimated. For both natural and mitigated ELMs a broadening of the divertor ELM-wetted area with increasing ELM size has been found. In disruption studies with massive gas injection up to 50% of the thermal energy could be radiated before, and 20% during, the thermal quench. Halo currents could be reduced by 60% and, using argon/deuterium and neon/deuterium gas mixtures, runaway electron generation could be avoided. Most objectives of the ITER-like ICRH antenna have been demonstrated; matching with closely packed straps, ELM resilience, scattering matrix arc detection and operation at high power density (6.2 MW m-2) and antenna strap voltages (42 kV). Coupling measurements are in very good agreement with TOPICA modelling. © 2011 IAEA, Vienna.
|
|
| 2. |
- Abel, I, et al.
(författare)
-
Overview of the JET results with the ITER-like wall
- 2013
-
Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 53:10, s. 104002-
-
Tidskriftsartikel (refereegranskat)abstract
- Following the completion in May 2011 of the shutdown for the installation of the beryllium wall and the tungsten divertor, the first set of JET campaigns have addressed the investigation of the retention properties and the development of operational scenarios with the new plasma-facing materials. The large reduction in the carbon content (more than a factor ten) led to a much lower Z(eff) (1.2-1.4) during L- and H-mode plasmas, and radiation during the burn-through phase of the plasma initiation with the consequence that breakdown failures are almost absent. Gas balance experiments have shown that the fuel retention rate with the new wall is substantially reduced with respect to the C wall. The re-establishment of the baseline H-mode and hybrid scenarios compatible with the new wall has required an optimization of the control of metallic impurity sources and heat loads. Stable type-I ELMy H-mode regimes with H-98,H-y2 close to 1 and beta(N) similar to 1.6 have been achieved using gas injection. ELM frequency is a key factor for the control of the metallic impurity accumulation. Pedestal temperatures tend to be lower with the new wall, leading to reduced confinement, but nitrogen seeding restores high pedestal temperatures and confinement. Compared with the carbon wall, major disruptions with the new wall show a lower radiated power and a slower current quench. The higher heat loads on Be wall plasma-facing components due to lower radiation made the routine use of massive gas injection for disruption mitigation essential.
|
|
| 3. |
|
|
| 4. |
- Giubilato, E, et al.
(författare)
-
Risk Management Framework for Nano-Biomaterials Used in Medical Devices and Advanced Therapy Medicinal Products
- 2020
-
Ingår i: Materials (Basel, Switzerland). - : MDPI AG. - 1996-1944. ; 13:20
-
Tidskriftsartikel (refereegranskat)abstract
- The convergence of nanotechnology and biotechnology has led to substantial advancements in nano-biomaterials (NBMs) used in medical devices (MD) and advanced therapy medicinal products (ATMP). However, there are concerns that applications of NBMs for medical diagnostics, therapeutics and regenerative medicine could also pose health and/or environmental risks since the current understanding of their safety is incomplete. A scientific strategy is therefore needed to assess all risks emerging along the life cycles of these products. To address this need, an overarching risk management framework (RMF) for NBMs used in MD and ATMP is presented in this paper, as a result of a collaborative effort of a team of experts within the EU Project BIORIMA and with relevant inputs from external stakeholders. The framework, in line with current regulatory requirements, is designed according to state-of-the-art approaches to risk assessment and management of both nanomaterials and biomaterials. The collection/generation of data for NBMs safety assessment is based on innovative integrated approaches to testing and assessment (IATA). The framework can support stakeholders (e.g., manufacturers, regulators, consultants) in systematically assessing not only patient safety but also occupational (including healthcare workers) and environmental risks along the life cycle of MD and ATMP. The outputs of the framework enable the user to identify suitable safe(r)-by-design alternatives and/or risk management measures and to compare the risks of NBMs to their (clinical) benefits, based on efficacy, quality and cost criteria, in order to inform robust risk management decision-making.
|
|
| 5. |
- Beurskens, M. N. A., et al.
(författare)
-
Pedestal width and ELM size identity studies in JET and DIII-D; implications for ITER
- 2009
-
Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 0741-3335 .- 1361-6587. ; 51:12, s. 124051-
-
Tidskriftsartikel (refereegranskat)abstract
- The dependence of the H-mode edge transport barrier width on normalized ion gyroradius (rho* = rho/a) in discharges with type I ELMs was examined in experiments combining data for the JET and DIII-D tokamaks. The plasma configuration as well as the local normalized pressure (beta), collisionality (nu*), Mach number and the ratio of ion and electron temperature at the pedestal top were kept constant, while rho* was varied by a factor of four. The width of the steep gradient region of the electron temperature (T-e) and density (n(e)) pedestals normalized to machine size showed no or only a weak trend with rho*. A rho(1/2) or rho(1) dependence of the pedestal width, given by some theoretical predictions, is not supported by the current experiments. This is encouraging for the pedestal scaling towards ITER as it operates at lower rho* than existing devices. Some differences in pedestal structure and ELM behaviour were, however, found between the devices; in the DIII-D discharges, the n(e) and T-e pedestal were aligned at high rho* but the ne pedestal shifted outwards in radius relative to T-e as rho* decreases, while on JET the profiles remained aligned while rho* was scanned by a factor of two. The energy loss at an ELM normalized to the pedestal energy increased from 10% to 40% as rho* increased by a factor of two in the DIII-D discharges but no such variation was observed in the case of JET. The measured pedestal pressures and widths were found to be consistent with the predictions from modelling based on peeling-ballooning stability theory, and are used to make projections towards ITER
|
|
| 6. |
- Moreau, D., et al.
(författare)
-
A two-time-scale dynamic-model approach for magnetic and kinetic profile control in advanced tokamak scenarios on JET
- 2008
-
Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 48:10
-
Tidskriftsartikel (refereegranskat)abstract
- Real-time simultaneous control of several radially distributed magnetic and kinetic plasma parameters is being investigated on JET, in view of developing integrated control of advanced tokamak scenarios. This paper describes the new model-based profile controller which has been implemented during the 2006-2007 experimental campaigns. The controller aims to use the combination of heating and current drive (H&CD) systems-and optionally the poloidal field (PF) system-in an optimal way to regulate the evolution of plasma parameter profiles such as the safety factor, q(x), and gyro-normalized temperature gradient,. rho*(Te)(x). In the first part of the paper, a technique for the experimental identification of a minimal dynamic plasma model is described, taking into account the physical structure and couplings of the transport equations, but making no quantitative assumptions on the transport coefficients or on their dependences. To cope with the high dimensionality of the state space and the large ratio between the time scales involved, the model identification procedure and the controller design both make use of the theory of singularly perturbed systems by means of a two-time-scale approximation. The second part of the paper provides the theoretical basis for the controller design. The profile controller is articulated around two composite feedback loops operating on the magnetic and kinetic time scales, respectively, and supplemented by a feedforward compensation of density variations. For any chosen set of target profiles, the closest self-consistent state achievable with the available actuators is uniquely defined. It is reached, with no steady state offset, through a near-optimal
|
|
| 7. |
- Solano, E. R., et al.
(författare)
-
Observation of Confined Current Ribbon in JET Plasmas
- 2010
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 104:18, s. 185003-
-
Tidskriftsartikel (refereegranskat)abstract
- We report the identification of a localized current structure inside the JET plasma. It is a field-aligned closed helical ribbon, carrying current in the same direction as the background current profile (cocurrent), rotating toroidally with the ion velocity (corotating). It appears to be located at a flat spot in the plasma pressure profile, at the top of the pedestal. The structure appears spontaneously in low density, high rotation plasmas, and can last up to 1.4 s, a time comparable to a local resistive time. It considerably delays the appearance of the first edge localized mode.
|
|
| 8. |
- Zabeo, Davide, 1992, et al.
(författare)
-
A lumenal interrupted helix in human sperm tail microtubules
- 2018
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- Eukaryotic flagella are complex cellular extensions involved in many human diseases gathered under the term ciliopathies. Currently, detailed insights on flagellar structure come mostly from studies on protists. Here, cryo-electron tomography (cryo-ET) was performed on intact human spermatozoon tails and showed a variable number of microtubules in the singlet region (inside the end-piece). Inside the microtubule plus end, a novel left-handed interrupted helix which extends several micrometers was discovered. This structure was named Tail Axoneme Intra-Lumenal Spiral (TAILS) and binds directly to 11 protofilaments on the internal microtubule wall, in a coaxial fashion with the surrounding microtubule lattice. It leaves a gap over the microtubule seam, which was directly visualized in both singlet and doublet microtubules. We speculate that TAILS may stabilize microtubules, enable rapid swimming or play a role in controlling the swimming direction of spermatozoa.
|
|
| 9. |
- Beurskens, M N A, et al.
(författare)
-
H-mode pedestal scaling in DIII-D, ASDEX Upgrade, and JET
- 2011
-
Ingår i: Physics of Plasmas. - : AIP Publishing. - 1070-664X .- 1089-7674. ; 18:5
-
Tidskriftsartikel (refereegranskat)abstract
- Multidevice pedestal scaling experiments in the DIII-D, ASDEX Upgrade (AUG), and JET tokamaks are presented in order to test two plasma physics pedestal width models. The first model proposes a scaling of the pedestal width Delta/a proportional to rho*(1/2) to rho* based on the radial extent of the pedestal being set by the point where the linear turbulence growth rate exceeds the E x B velocity. In the multidevice experiment where rho* at the pedestal top was varied by a factor of four while other dimensionless parameters where kept fixed, it has been observed that the temperature pedestal width in real space coordinates scales with machine size, and that therefore the gyroradius scaling suggested by the model is not supported by the experiments. The density pedestal width is not invariant with rho* which after comparison with a simple neutral fuelling model may be attributed to variations in the neutral fuelling patterns. The second model, EPED1, is based on kinetic ballooning modes setting the limit of the radial extent of the pedestal region and leads to Delta(psi) proportional to beta p(1/2). All three devices show a scaling of the pedestal width in normalised poloidal flux as Delta(psi) proportional to beta p(1/2), as described by the kinetic ballooning model; however, on JET and AUG, this could not be distinguished from an interpretation where the pedestal is fixed in real space. Pedestal data from all three devices have been compared with the predictive pedestal model EPED1 and the model produces pedestal height values that match the experimental data well.
|
|
| 10. |
- Croft, Jacob, 1996, et al.
(författare)
-
Composition, structure and function of the eukaryotic flagellum distal tip
- 2018
-
Ingår i: Essays in biochemistry. - 1744-1358. ; 62:6, s. 815-828
-
Forskningsöversikt (refereegranskat)abstract
- Cilia and flagella are long extensions commonly found on the surface of eukaryotic cells. In fact, most human cells have a flagellum, and failure to correctly form cilia leads to a spectrum of diseases gathered under the name 'ciliopathies'. The cilium distal tip is where it grows and signals. Yet, out of the flagellar regions, the distal tip is probably the least intensively studied. In this review, we will summarise the current knowledge on the diverse flagellar tip structures, the dynamicity and signalling that occurs here and the proteins localising to this important cellular region.
|
|
| 11. |
- Cvjetkovic, Aleksander, et al.
(författare)
-
Extracellular vesicles in motion
- 2017
-
Ingår i: Science Matters. - : Sciencematters. - 2297-8240 .- 2297-9239.
-
Tidskriftsartikel (refereegranskat)abstract
- By secreting extracellular vesicles (EVs), including exosomes and microvesicles, into the extracellular milieu, cells can convey complex biological messages between each other. These vesicles are generally thought to be static packages lacking the flexibility of their parental cells in terms of motility and the ability to change shape. However, cryo-electron micrographs reveal the presence of actin-like filaments in a subpopulation of EVs, raising the question if these vesicles could possess motile capabilities similar to that produced by actin in cells. We here show that fluorescently labeled EVs change their shape in a matter of minutes, regardless of whether they are isolated from human body fluids, mouse tissue or cell culture of human cells or yeast. Our findings therefore cast doubt on movement being confined to cells, suggesting that some EVs indeed have an intrinsic capacity to move. This novel observation showing morphological plasticity among EVs adds another level of complexity to the already multifaceted vesicular secretome, and may lead to new ways in which we perceive these nano-carriers of intercellular signals.
|
|
| 12. |
- Gui, Miao, et al.
(författare)
-
SPACA9 is a lumenal protein of human ciliary singlet and doublet microtubules
- 2022
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 1091-6490. ; 119:41
-
Tidskriftsartikel (refereegranskat)abstract
- The cilium-centrosome complex contains triplet, doublet, and singlet microtubules. The lumenalsurfaces of each microtubule within this diverse array are decorated by microtubule inner proteins (MIPs). Here, we used single-particle cryo-electron microscopy methods to build atomic models of two types of human ciliary microtubule: the doublet microtubules of multiciliated respiratory cells and the distal singlet microtubules of monoflagellated human spermatozoa. We discover that SPACA9 is a polyspecific MIP capable of binding both microtubule types. SPACA9 forms intralumenal striations in the B tubule of respiratory doublet microtubules and noncontinuous spirals in sperm singlet microtubules. By acquiring new and reanalyzing previous cryo-electron tomography data, we show that SPACA9-like intralumenal striations are common features of different microtubule types in animal cilia. Our structures provide detailed references to help rationalize ciliopathy-causing mutations and position cryo-EM as a tool for the analysis of samples obtained directly from ciliopathy patients.
|
|
| 13. |
- Litaudon, X., et al.
(författare)
-
Development of steady-state scenarios compatible with ITER-like wall conditions
- 2007
-
Ingår i: Plasma Physics and Controlled Fusion. - 0741-3335 .- 1361-6587. ; 49:12B, s. B529-B550
-
Tidskriftsartikel (refereegranskat)abstract
- A key issue for steady-state tokamak operation is to determine the edge conditions that are compatible both with good core confinement and with the power handling and plasma exhaust capabilities of the plasma facing components (PFCs) and divertor systems. A quantitative response to this open question will provide a robust scientific basis for reliable extrapolation of present regimes to an ITER compatible steady-state scenario. In this context, the JET programme addressing steady-state operation is focused on the development of non-inductive, high confinement plasmas with the constraints imposed by the PFCs. A new beryllium main chamber wall and tungsten divertor together with an upgrade of the heating/fuelling capability are currently in preparation at JET. Operation at higher power with this ITER-like wall will impose new constraints on non-inductive scenarios. Recent experiments have focused on the preparation for this new phase of JET operation. In this paper, progress in the development of advanced tokamak (AT) scenarios at JET is reviewed keeping this long-term objective in mind. The approach has consisted of addressing various critical issues separately during the 2006-2007 campaigns with a view to full scenario integration when the JET upgrades are complete. Regimes with internal transport barriers (ITBs) have been developed at q(95) similar to 5 and high triangularity, 3 (relevant to the ITER steady-state demonstration) by applying more than 30 MW of additional heating power reaching beta(N) similar to 2 at B(o) similar to 3.1 T. Operating at higher 6 has allowed the edge pedestal and core densities to be increased pushing the ion temperature closer to that of the electrons. Although not yet fully integrated into a performance enhancing ITB scenario, Neon seeding has been successfully explored to increase the radiated power fraction (up to 60%), providing significant reduction of target tile power fluxes (and hence temperatures) and mitigation of edge localized mode (ELM) activity. At reduced toroidal magnetic field strength, high beta(N) regimes have been achieved and q-profile optimization investigated for use in steady-state scenarios. Values of beta(N) above the 'no-wall magnetohydrodynamic limit' (beta(N) similar to 3.0) have been sustained for a resistive current diffusion time in high-delta configurations (at 1.2 MA/1.8 T). In this scenario, ELM activity has been mitigated by applying magnetic perturbations using error field correction coils to provide ergodization of the magnetic field at the plasma edge. In a highly shaped, quasi-double null X-point configuration, ITBs have been generated on the ion heat transport channel and combined with 'grassy' ELMs with similar to 30 MW of applied heating power (at 1.2 MA/2.7 T, q(95) similar to 7). Advanced algorithms and system identification procedures have been developed with a view to developing simultaneously temperature and q-profile control in real-time. These techniques have so far been applied to the control of the q-profile evolution in JET AT scenarios.
|
|
| 14. |
- Mantica, P., et al.
(författare)
-
Experimental Study of the Ion Critical-Gradient Length and Stiffness Level and the Impact of Rotation in the JET Tokamak
- 2009
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 102:17
-
Tidskriftsartikel (refereegranskat)abstract
- Experiments were carried out in the JET tokamak to determine the critical ion temperature inverse gradient length (R/L-Ti = R vertical bar del T-i vertical bar/T-i) for the onset of ion temperature gradient modes and the stiffness of Ti profiles with respect to deviations from the critical value. Threshold and stiffness have been compared with linear and nonlinear predictions of the gyrokinetic code GS2. Plasmas with higher values of toroidal rotation show a significant increase in R/L-Ti, which is found to be mainly due to a decrease of the stiffness level. This finding has implications on the extrapolation to future machines of present day results on the role of rotation on confinement.
|
|
| 15. |
- Mantica, P., et al.
(författare)
-
Experimental Study of the Ion Critical Gradient Length and Stiffness Level and the Impact of Rotational Shear in the JET Tokamak
- 2008
-
Ingår i: Proceedings of the 22nd IAEA Fusion Energy Conference.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Experiments have been carried out in the JET tokamak in order to determine the critical iontemperature inverse gradient length (R/LTi =R|∇Ti|/Ti) for the onset of Ion Temperature Gradientmodes and the stiffness of Ti profiles with respect to deviations from the critical value. The existenceof a threshold in R/LTi has been assessed and its value found in close agreement with linear GS2gyro-kinetic calculations. The ion stiffness level is high and keeps R/LTi close to the linear thresholdirrespective of the amount of core ion heating. This finding is not in agreement with non-linear GS2calculations, yielding significantly higher R/LTi values than the linear threshold. Comparison ofplasmas with different values of toroidal rotation indicates a significant increase in R/LTi in rotatingplasmas. Various observations allow to conclude that such increase is mainly due to a decrease ofthe stiffness level with increasing rotation, rather than to a mere up-shift of the threshold, as commonlypredicted by theory. This finding has implications on the interpretation of present day experimentalresults on the effect of rotation on confinement as well as on extrapolations to future machines.
|
|
| 16. |
- Mazon, D., et al.
(författare)
-
Real-time profile control for advanced Tokamak operation
- 2008
-
Ingår i: AIP Conf. Proc.. - : AIP. - 9780735405073 ; , s. 430-433
-
Konferensbidrag (refereegranskat)abstract
- Simultaneous control of the plasma shape, the magnetic and kinetic plasma profiles (such as the safety factor, q(x), and gyro-normalized temperature gradient, ρTe *;(x), respectively) and the boundary flux is being investigated on JET, and has potential applications in the operation of ITER steady state advanced tokamak discharges. The control of radially distributed parameters was achieved for the first time on JET in 2004 [1-4]. The controller was based on the static plasma response only. The approach newly implemented on JET aims to use a dynamical plasma model, all the available heating and current drive (H&CD) systems, and the poloidal field (PF) system in an optimal way to achieve a set of requested magnetic and kinetic profiles. This paper describes the new model-based optimal profile controller which has been tested during the last 2007 experimental campaign. The controller aims to use the combination of heating and current drive systems - and optionally the PF system. First experimental results of current profile control obtained during the last 2007 JET campaign are presented.
|
|
| 17. |
- Osborne, T. H., et al.
(författare)
-
Scaling of H-Mode Pedestal and ELM Characteristics in the JET and DIII-D Tokamaks
- 2010
-
Konferensbidrag (refereegranskat)abstract
- The dependence of the H-mode edge pedestal width and Type I edge localized mode (ELM) characteristics on ion gyro-radius, ρ*=ρ/a, was studied in experiments combining data from the JET and DIII-D tokamaks to achieve a factor of 4 variation in ρ* [M.N.A. Beurskens, et al., Plasma Phys. Control. Fusion (2010)]. No change was found in the radial or poloidal correlation lengths of density fluctuations in the ETB as a function of ρ*. The ELM energy loss normalized to the pedestal energy increased with ρ* on DIII-D to twice the value expected from an established scaling with collisionality; however, this trend was reversed on JET where the ΔWELM/WPED instead decreased weakly with increasing ρ*. The ELM size was also correlated with the proximity of the density to the value at which the power for transition from L- to H-mode is a minimum.
|
|
| 18. |
|
|
| 19. |
- Zabeo, Davide, 1992, et al.
(författare)
-
3D ultrastructure of multi-vesicular bodies in fission yeast
- 2017
-
Ingår i: Science Matters. - : Sciencematters. - 2297-8240 .- 2297-9239. ; 3:3
-
Tidskriftsartikel (refereegranskat)abstract
- The multi-vesicular body (MVB) organelle and the cellular sorting pathway associated with it are very well characterized in budding yeast (Saccharomyces cerevisiae). However, little is known about MVB structure and function in fission yeast (Schizosaccharomyces pombe). In this work, we investigated and characterized the three-dimensional ultrastructure of MVBs in S. pombe using electron tomography. We discovered a positive correlation between MVB size and the number of intralumenal vesicles (ILVs) contained in them. MVBs grew larger with the progression of the cell cycle, hinting at an unknown interaction between the regulation of the two processes. Larger MVBs were also observed in the temperature-sensitive cdc25-22 mutant, which is defective in cell cycle progression into mitosis at the restrictive temperature. This study offers, to our knowledge, the first electron microscopic observation and tomographic reconstruction of MVBs in S. pombe.
|
|
| 20. |
- Zabeo, Davide, 1992, et al.
(författare)
-
Axonemal doublet microtubules can split into two complete singlets in human sperm flagellum tips.
- 2019
-
Ingår i: FEBS letters. - : Wiley. - 1873-3468 .- 0014-5793. ; 593:9, s. 892-902
-
Tidskriftsartikel (refereegranskat)abstract
- Motile flagella are crucial for human fertility and embryonic development. The distal tip of the flagellum is where growth and intra-flagellar transport are coordinated. In most model organisms, but not all, the distal tip includes a 'singlet region', where axonemal doublet microtubules (dMT) terminate and only complete A-tubules extend as singlet microtubules (sMT) to the tip. How a human flagellar tip is structured is unknown. Here, the flagellar tip structure of human spermatozoa was investigated by cryo-electron tomography, revealing the formation of a complete sMT from both the A-tubule and B-tubule of dMTs. This different tip arrangement in human spermatozoa shows the need to investigate human flagella directly in order to understand their role in health and disease.
|
|
| 21. |
- Zabeo, Davide, 1992, et al.
(författare)
-
Exosomes purified from a single cell type have diverse morphology
- 2017
-
Ingår i: Journal of extracellular vesicles. - : Wiley. - 2001-3078. ; 6:1
-
Tidskriftsartikel (refereegranskat)abstract
- Extracellular vesicles (EVs) are produced by all known organisms and are important for cell communication and physiology. Great morphological diversity has been described regarding EVs found in body fluids such as blood plasma, breast milk, and ejaculate. However, a detailed morphological analysis has never been performed on exosomes when purified from a single cell type. In this study we analysed and quantified, via multiple electron microscopy techniques, the morphology of exosomes purified from the human mast cell line HMC-1. The results revealed a wide diversity in exosome morphology, suggesting that subpopulations of exosomes with different and specific functions may exist. Our findings imply that a new, more efficient way of defining exosome subpopulations is necessary. A system was proposed where exosomes were classified into nine different categories according to their size and shape. Three additional morphological features were also found in exosomes regardless of their morphological classification. These findings show that exosomes purified from a single cell line are also morphologically diverse, similar to previous observations for EVs in body fluids. This knowledge can help to improve the interpretation of experimental results and widen our general understanding of the biological functions of exosomes.
|
|
