Neurogenerative Diseases - 20

on their chemical and physical properties. And given
that sonication is quite violent in molecular terms,
we hypothesized that the effects of sonication on
alpha-synuclein fibrils would result in a dramatic
increase in solubility, something not communicated
in the scientific literature.

from about 70 nm to just under 40 nm (Figure 5).
However, more interestingly, the fibrils went from
being overwhelmingly insoluble prior to sonication
to being fully soluble at the maximum setting
(Figure 6). This dramatic increase in solubility is
very likely the key reason that sonicated fibrils
perform well in in vitro and in vivo experiments,
whereas unsonicated or poorly sonicated fibrils do
not. This is borne out by the fact that the fibril size
does not change dramatically, despite decreasing
by about 40% of their original size at the maximum
setting tested. Although fibril size reduction may
be an indication of successful sonication, it is the
solvation of these fibrils that is highly likely to be
far more important. The removal of any limitations,
likely diffusional, inherent in a two-phase system
(aqueous and solid-represented by the monomers
and fibril reactants, respectively), is much more likely
to be indicative of the increased fibrillar activity that
has generally been associated with these sonicated
constructs in living systems.

Molecular interactions can become more rapid by
orders of magnitude when limitations, including
diffusional ones, are removed. This would be the case
if fibrils entered the aqueous, solvated phase from the
solid phase. In order to test whether increased solubility
occurs after high levels of sonication, we measured
the levels of fibrillar material in solution qualitatively
(on gels) using sedimentation assays after introducing
increasing levels of sonication. The average fibril size
was measured as well, which could be expected to
decrease with increased sonication time.
The results of this experiment were very clear.
As sonication time was increased using a probe
sonicator, the average fibril size was reduced

Figure 5. Increased sonication (both amplitude and number of
pulses) decreases the size of A53T mutant alpha-synuclein PFFs
(SPR-326). Unsonicated fibrils are longer, on average, than fibrils
sonicated for 120 pulses at 40% amplitude.

Figure 6. Sonication increases the solubility of A53T mutant alphasynuclein PFFs (SPR-326). Unsonicated fibrils are contained largely in
the pellet and not the supernatant, whereas highly sonicated fibrils
are contained in the supernatant and not the pellet.

https://www.stressmarq.com/products/protein/alpha-synuclein-protein-spr-326/ https://www.stressmarq.com/products/protein/alpha-synuclein-protein-spr-326/

Neurogenerative Diseases

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