Nanoscale Correlated Disorder in Out-of-Equilibrium Myelin Ultrastructure

Campi, Gaetano; Gioacchino, Michael Di; Poccia, Nicola; Ricci, Alessandro; Burghammer, Manfred; Ciasca, Gabriele; Bianconi, A.

doi:10.1021/acsnano.7b07897

Cited by 20 publications

(30 citation statements)

References 71 publications

(237 reference statements)

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“…This is a situation where the size of the different phase regions (ordered, disordered, etc.) begin to fluctuate, in a correlated way, over increasingly large length scales (38), as shown, for instance, in previous work on myelin (17,18). In this work, we have been interested to clarify the role of myelin proteins dynamics, in particular of MBP, on the myelin ultrastructure functional fluctuations.…”

Section: Introductionmentioning

confidence: 80%

“…Diffraction images were calibrated using silver behenate powder (AgC 22 H 43 O 2 ), which has a fundamental spacing of d 001 =58.38 Å. We choose an exposure time of 300 ms to minimize radiation damage without affecting sensitivity at the same time (17,18). The crossed bundle is of approximately 50 myelinated axons.…”

Section: Scanning Micro X-ray Diffractionmentioning

confidence: 99%

“…In particular, the myelin sheath has several roles including: the control of the propagation speed of action potentials in saltatory conduction, facilitating nerve signal transmission (12)(13)(14)(15), and the mechanical support (14,15). The myelin ultrastructure has a structural unit constituted by the stacking of the four layers: (i) lipidic membrane (lipid polar group, l pg), (ii) cytoplasmatic apposition, cyt, (iii) a second lipidic membrane, l pg, and (iv) extracellular apposition, ext, as shown in the pictorial view of Figure 1 (16)(17)(18).…”

Section: Introductionmentioning

confidence: 99%

“…In this work, we have been interested to clarify the role of myelin proteins dynamics, in particular of MBP, on the myelin ultrastructure functional fluctuations. To tackle this issue, we have used new powerful non-invasive high spatial resolution techniques developed thanks to the latest generation synchrotron sources, advanced focusing optics and fast acquisition methods (17,18,(39)(40)(41)(42). More specifically, we have followed a methodological strategy consisting in two main steps.…”

Section: Introductionmentioning

confidence: 99%

“…More specifically, we have followed a methodological strategy consisting in two main steps. In the first step we have used Scanning micro X Ray Diffraction (SµXRD) to measure ultrastructural fluctuations of myelin in both out-of-equilibrium physiological and in-equilibrium non-physiological conditions obtained by changing the pH of myelin environment (17,18). We paid particular attention to the fluctuations of the cytosolic apposition, where the MBP, P2 and P0 proteins act to preserve myelin structure and functionality.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Myelin Basic Protein dynamics from out-of-equilibrium functional state to degraded state in myelin

Gioacchino

Bianconi

Burghammer

et al. 2019

Preprint

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Living matter is a quasi-stationary out-of-equilibrium system; in this physical condition, structural fluctuations at nano-and meso-scales are needed to understand the physics behind its biological functionality. Myelin has a simple ultrastructure whose fluctuations show correlated disorder in its functional out-of-equilibrium state. However, there is no information on the relationship between this correlated disorder and the dynamics of the intrinsically disordered Myelin Basic Protein (MBP) which is expected to influence the membrane structure and overall functionality. In this work, we have investigated the role of this protein structural dynamics in the myelin ultrastructure fluctuations in and out-of-equilibrium conditions, by using synchrotron Scanning micro X Ray Diffraction and Small Angle X ray Scattering. We have induced the crossover from out-of-equilibrium functional state to in-equilibrium degeneration changing the pH far away from physiological condition. While the observed compression of the cytosolic layer thickness probes the unfolding of the P2 protein and of the cytoplasmic P0 domain (P0 cyt ), the intrinsic large MBP fluctuations preserve the cytosol structure also in the degraded state. Thus, the transition of myelin ultrastructure from correlated to uncorrelated disordered state, is significantly affected by the unfolding of the P2 and P0 proteins, which in this latter state do not act in synergistic manner with MBP to determine the membrane functionality. STATEMENT OF SIGNIFICANCEA better comprehension of myelin degenerative process and the role of protein dynamics in this biological membrane is a topic issue in today's scientific community. The myelin ultrastructural fluctuations exhibit correlated disorder in its functional state, that becomes uncorrelated as it degenerates. In this work we elucidate the interplay of protein structural dynamics and myelin ultrastructure in the transition from its functional state to the degraded state. The results highlight that the intrinsically disordered Myelin Basic Protein (MBP) allows to preserve the myelin structure following both the small correlated fluctuations in physiological state and the large disordered fluctuations in degraded conditions, where the myelin functionality is close to being lost and the MBP remains the single active protein.

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Section: Introductionmentioning

confidence: 80%

Section: Scanning Micro X-ray Diffractionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Myelin Basic Protein dynamics from out-of-equilibrium functional state to degraded state in myelin

Gioacchino

Bianconi

Burghammer

et al. 2019

Preprint

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Structural Fluctuations at Nanoscale in Complex Functional Materials

Campi

2021

Springer Proceedings in Physics

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Post mortem computed tomography meets radiomics: a case series on fractal analysis of post mortem changes in the brain

et al. 2022

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Estimating the post-mortem interval is a fundamental, albeit challenging task in forensic sciences. To this aim, forensic practitioners need to assess post-mortem changes through a plethora of different methods, most of which are inherently qualitative, thus providing broad time intervals rather than precise determinations. This challenging problem is further complicated by the influence of environmental factors, which modify the temporal dynamics of post-mortem changes, sometimes in a rather unpredictable fashion. In this context, the search for quantitative and objective descriptors of post-mortem changes is highly demanded. In this study, we used computed tomography (CT) to assess the post-mortem anatomical modifications occurring in the time interval 0–4 days after death in the brain of four corpses. Our results show that fractal analysis of CT brain slices provides a set of quantitative descriptors able to map post-mortem changes over time throughout the whole brain. Although incapable of producing a direct estimation of the PMI, these descriptors could be used in combination with other more established methods to improve the accuracy and reliability of PMI determination.

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Nanoscale Correlated Disorder in Out-of-Equilibrium Myelin Ultrastructure

Cited by 20 publications

References 71 publications

Myelin Basic Protein dynamics from out-of-equilibrium functional state to degraded state in myelin

Myelin Basic Protein dynamics from out-of-equilibrium functional state to degraded state in myelin

Structural Fluctuations at Nanoscale in Complex Functional Materials

Post mortem computed tomography meets radiomics: a case series on fractal analysis of post mortem changes in the brain

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