<table><tbody><tr><td>Amyloid beta peptide 1-40 (A&amp;beta;&lt;sub&gt;1&amp;ndash;40&lt;/sub&gt; peptide)</td><td>r-Peptide (Bogart, GA, USA)</td><td>A-1156-2</td><td></td></tr><tr><td>CCD digital camera</td><td>AMT</td><td>XR-40 4-megapixel CCD&amp;nbsp;</td><td></td></tr><tr><td>Distilled deionized water from Milli-Q- water system</td><td>Millipore Sigma (Burlington, MA, USA)</td><td>Milli-Q IQ 7000</td><td></td></tr><tr><td>Freezer -86 &lt;sup&gt;o&lt;/sup&gt;C</td><td>Thermo Scientific</td><td>Revco Chilly Willy&amp;nbsp; RLE Series Unit ID 187004 Build Number 40.04</td><td></td></tr><tr><td>Gold Colloid (10 nm)</td><td>Ted Pella, Inc. (Redding, California, USA)</td><td>15703-20</td><td></td></tr><tr><td>Gold Colloid (100 nm)</td><td>Ted Pella, Inc. (Redding, California, USA)</td><td>15711-22</td><td></td></tr><tr><td>Gold Colloid (15 nm)</td><td>Ted Pella, Inc. (Redding, California, USA)</td><td>15704-20</td><td></td></tr><tr><td>Gold Colloid (20 nm)</td><td>Ted Pella, Inc. (Redding, California, USA)</td><td>15705-20</td><td></td></tr><tr><td>Gold Colloid (30 nm)</td><td>Ted Pella, Inc. (Redding, California, USA)</td><td>15706-21</td><td></td></tr><tr><td>Gold Colloid (40 nm)</td><td>Ted Pella, Inc. (Redding, California, USA)</td><td>15707-21</td><td></td></tr><tr><td>Gold Colloid (50 nm)</td><td>Ted Pella, Inc. (Redding, California, USA)</td><td>15708-21</td><td></td></tr><tr><td>Gold Colloid (60 nm)</td><td>Ted Pella, Inc. (Redding, California, USA)</td><td>15709-22</td><td></td></tr><tr><td>Gold Colloid (80 nm)</td><td>Ted Pella, Inc. (Redding, California, USA)</td><td>15710-22</td><td></td></tr><tr><td>Highest Grade V1AFM Mica Discs 10 mm</td><td>Ted Pella Inc.</td><td>#50</td><td></td></tr><tr><td>Hydrochloric Acid Standard Solution, 1.0 N</td><td>Fluka</td><td>Lot# SHBB4705V&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; 318949-2L</td><td></td></tr><tr><td>Macro quartz quvette Light Path 10 mm</td><td>Fire Fly Science&amp;nbsp;</td><td>Type1-MC-Path10mm</td><td></td></tr><tr><td>Micro pH electrode</td><td>HORIBA</td><td>Model 9618S (MFG No. 9Y8E0050)</td><td></td></tr><tr><td>Peak Fit Program</td><td>Origin (Northampton, MA, USA)</td><td>OriginPro2018b (64-bit) b9.5.5.409 (Academic)</td><td></td></tr><tr><td>pH 4.00 Buffer solution&amp;nbsp;</td><td>VWR</td><td>Cat No. 34170-127</td><td></td></tr><tr><td>pH 7.00 Buffer Solution&amp;nbsp;</td><td>Fisher Chemical</td><td>SB107-4 Lot 191041</td><td></td></tr><tr><td>pH meter</td><td>HORIBA</td><td>Model F-72G (MFG No. B27M0017)</td><td></td></tr><tr><td>Pipet Tips &amp;nbsp;Maxi Tips 1&amp;ndash;5 mL</td><td>Fisher&amp;nbsp;&amp;nbsp;</td><td>02-707-467</td><td></td></tr><tr><td>Pipet Tips 10 mL</td><td>Fisher</td><td>02-717-135</td><td></td></tr><tr><td>Pipet Tips 1000 mL</td><td>Fisher</td><td>02-717-156</td><td></td></tr><tr><td>Pipet Tips 1&amp;ndash;200 mL</td><td>Fisher</td><td>02-717-143</td><td></td></tr><tr><td>Pipetter Fisher Brand Elite 0.5&amp;ndash;5 mL</td><td>Fisher</td><td>QU05317</td><td></td></tr><tr><td>Pipetter Fisher Brand Elite 100&amp;ndash;1000 mL</td><td>Fisher</td><td>QU01672</td><td></td></tr><tr><td>Pipetter Fisher Brand Elite 10&amp;ndash;100 mL</td><td>Fisher</td><td>MU10985</td><td></td></tr><tr><td>Pipetter Fisher Brand Elite 1&amp;ndash;10 mL</td><td>Fisher</td><td>MU08178</td><td></td></tr><tr><td>Sodium Hydroxide Solution 1.0 M</td><td>Fluka</td><td>Lot#05096BPV&amp;nbsp;&amp;nbsp; 319511-2L</td><td></td></tr><tr><td>TEM</td><td>FEI Co</td><td>Morgagni model 268&amp;nbsp;</td><td></td></tr><tr><td>TempAssure PCR Tubes, Flat Caps, Natural&amp;nbsp;</td><td>USA Scientific</td><td></td><td>polypropylene. 0.2 mL individual thin-wall tubes with attached frosted flat caps</td></tr><tr><td>UV-Vis-NIR Spectrophotometer</td><td>Varian</td><td>CARY 5000 UV1106M074</td><td></td></tr><tr><td>WI Tec alpha300R Confocal Raman Microscope</td><td>WITec-Oxford Instrument</td><td>XMB3000-3001</td><td></td></tr></tbody></table>

characterization of ph-dependent reversible self-assembly of amyloid beta 1-40-coated gold colloids

Amiloid Beta 1-40 Kaplı Altın Kolloidlerin pH'a Bağlı Tersinir Kendi Kendine Montajının Karakterizasyonu

The characterization of A&#946;1-40 coated over the nano-gold colloidal particle surfaces was conducted using surface plasmon resonance (SPR) spectroscopy ...

characterization-ph-dependent-reversible-self-assembly-amyloid-beta-1

Research

JoVE Journal

Biochemistry

Characterization of pH-Dependent Reversible Self-Assembly of Amyloid Beta 1-40-Coated Gold Colloids

152 Görüntüleme.  State University of New York Geneseo College. Burada, amiloid beta 1-40 (Aβ 1-40) kaplı 20 nm altın agregalarının yarı tersinir kendi kendine montajını tanımlayan sistematik bir yöntem sunuyoruz. Peptitler arasındaki nano boyuta bağlı yarı tersinir ağ, spesifik amino asitler veya Aβ 1-40 monomerinin bölümleri ile ilişkilendirildi.

Video: Amiloid Beta 1-40 Kaplı Altın Kolloidlerin pH'a Bağlı Tersinir Kendi Kendine Montajının Karakterizasyonu

Detection of the pH-dependent Activity of Escherichia coli Chaperone HdeB In Vitro and In Vivo

Bacteria are frequently exposed to environmental changes, such as alterations in pH, temperature, redox status, light exposure or mechanical force. Many of these conditions cause protein unfolding in the cell and have detrimental impact on the survival of the organism. A group of unrelated, stress-specific molecular chaperones have been shown to play essential roles in the survival of these stress conditions. While fully folded and chaperone-inactive before stress, these proteins rapidly unfold and become chaperone-active under specific stress conditions. Once activated, these conditionally disordered chaperones bind to a large number of different aggregation-prone proteins, prevent their aggregation and either directly or indirectly facilitate protein refolding upon return to non-stress conditions. The primary approach for gaining a more detailed understanding about the mechanism of their activation and client recognition involves the purification and subsequent characterization of these proteins using in vitro chaperone assays. Follow-up in vivo stress assays are absolutely essential to independently confirm the obtained in vitro results.
This protocol describes in vitro and in vivo methods to characterize the chaperone activity of E. coli HdeB, an acid-activated chaperone. Light scattering measurements were used as a convenient read-out for HdeB&#39;s capacity to prevent acid-induced aggregation of an established model client protein, MDH, in vitro. Analytical ultracentrifugation experiments were applied to reveal complex formation between HdeB and its client protein LDH, to shed light into the fate of client proteins upon their return to non-stress conditions. Enzymatic activity assays of the client proteins were conducted to monitor the effects of HdeB on pH-induced client inactivation and reactivation. Finally, survival studies were used to monitor the influence of HdeB&#39;s chaperone function in vivo.

Detection of the pH-dependent Activity of Escherichia coli Chaperone HdeB In Vitro and In Vivo

This study describes biophysical, biochemical and molecular techniques to characterize the chaperone activity of Escherichia coli HdeB under acidic pH conditions. These methods have been successfully applied for other acid-protective chaperones such as HdeA and can be modified to work for other chaperones and stress conditions.

pH bağımlı aktivitenin tespiti<em&gt; Escherichia coli</em&gt; Chaperone HdeB<em&gt; İn Vitro</em&gt; ve<em&gt; İn Vivo</em

Bacteria are frequently exposed to environmental changes, such as alterations in pH, temperature, redox status, light exposure or mechanical force. Many ...

Biyokimya

A Facile and Efficient Approach for the Production of Reversible Disulfide Cross-linked Micelles

Nanomedicine is an emerging form of therapy that harnesses the unique properties of particles that are nanometers in scale for biomedical application. Improving drug delivery to maximize therapeutic outcomes and to reduce drug-associated side effects are some of the cornerstones of present-day nanomedicine. Nanoparticles in particular have found a wide application in cancer treatment. Nanoparticles that offer a high degree of flexibility in design, application, and production based on the tumor microenvironment are projected to be more effective with rapid translation into clinical practice. The polymeric micellar nano-carrier is a popular choice for drug delivery applications.
In this article, we describe a simple and effective protocol for synthesizing drug-loaded, disulfide cross-linked micelles based on the self-assembly of a well-defined amphiphilic linear-dendritic copolymer (telodendrimer, TD). TD is composed of polyethylene glycol (PEG) as the hydrophilic segment and a thiolated cholic acid cluster as the core-forming hydrophobic moiety attached stepwise to an amine-terminated PEG using solution-based peptide chemistry. Chemotherapy drugs, such as paclitaxel (PTX), can be loaded using a standard solvent evaporation method. The O2-mediated oxidation was previously utilized to form intra-micellar disulfide cross-links from free thiol groups on the TDs. However, the reaction was slow and not feasible for large-scale production. Recently, an H2O2-mediated oxidation method was explored as a more feasible and efficient approach, and it was 96 times faster than the previously reported method. Using this approach, 50 g of PTX-loaded, disulfide cross-linked nanoparticles have been successfully produced with narrow particle size distribution and high drug loading efficiency. The stability of the resulting micelle solution is analyzed using disrupting conditions such as co-incubation with a detergent, sodium dodecyl sulfate, with or without a reducing agent. The drug-loaded, disulfide cross-linked micelles demonstrated less hemolytic activity when compared to their non-cross-linked counterparts.

To deliver cancer drugs to tumor sites with high specificity and reduced side effects, new methods based on nanoparticles are required. Here, we describe disulfide cross-linked micelles that can be easily prepared by hydrogen peroxide-mediated oxidation and are able to dissociate efficiently under a reducing tumor environment to release payloads.

Döner disülfür Çapraz bağlı misellerin Üretimi için basit ve etkin Yaklaşım

Nanomedicine is an emerging form of therapy that harnesses the unique properties of particles that are nanometers in scale for biomedical application. ...

A Tailored HPLC Purification Protocol That Yields High-purity Amyloid Beta 42 and Amyloid Beta 40 Peptides, Capable of Oligomer Formation

Amyloidogenic peptides such as the Alzheimer's disease-implicated Amyloid beta (A&#946;), can present a significant challenge when trying to obtain high purity material. Here we present a tailored HPLC purification protocol to produce high-purity amyloid beta 42 (A&#946;42) and amyloid beta 40 (A&#946;40) peptides. We have found that the combination of commercially available hydrophobic poly(styrene/divinylbenzene) stationary phase, polymer laboratory reverse phase - styrenedivinylbenzene (PLRP-S) under high pH conditions, enables the attainment of high purity (&gt;95%) A&#946;42 in a single chromatographic run. The purification is highly reproducible and can be amended to both semi-preparative and analytical conditions depending upon the amount of material wished to be purified. The protocol can also be applied to the A&#946;40 peptide with identical success and without the need to alter the method.

Herein we report a tailored HPLC purification protocol that yields high-purity amyloid beta 42 (A&#946;42) and amyloid beta 40 (A&#946;40) peptides, capable of oligomer formation. Amyloid beta is a highly aggregation prone, hydrophobic peptide implicated in Alzheimer&#39;s disease. The amyloidogenic nature of the peptide makes its purification a challenge.

Bir Ismarlama HPLC Arıtma Protokolü That Oligomer Formasyonu Yetenekli Verim Yüksek saflıkta Amiloid Beta 42 ve Amiloid Beta 40 peptidler,

Amyloidogenic peptides such as the Alzheimer's disease-implicated Amyloid beta (A&#946;), can present a significant challenge when trying to obtain high ...

Regeneration of Arrayed Gold Microelectrodes Equipped for a Real-Time Cell Analyzer

The label-free cell-based assay is advantageous for biochemical study because of it does not require the use of experimental animals. Due to its ability to provide more dynamic information about cells under physiological conditions than classical biochemical assays, this label-free real-time cell assay based on the electric impedance principle is attracting more attention during the past decade. However, its practical utilization may be limited due to the relatively expensive cost of measurement, in which costly consumable disposable gold microchips are used for the cell analyzer. In this protocol, we have developed a general strategy to regenerate arrayed gold microelectrodes equipped for a commercial label-free cell analyzer. The regeneration process includes trypsin digestion, rinsing with ethanol and water, and a spinning step. The proposed method has been tested and shown to be effective for the regeneration and repeated usage of commercial electronic plates at least three times, which will help researchers save on the high running cost of real-time cell assays.

This protocol describes a general strategy to regenerate commercial arrayed gold microelectrodes equipped for a label-free cell analyzer aimed at saving on the high running costs ofmicrochip-based assays. The regeneration process includes trypsin digestion, rinsing with ethanol and water, and a spinning step, which enables repeated usage of microchips.

Rejenerasyon için gerçek zamanlı hücre Analyzer donatılmış dizilmiş altın Microelectrodes

The label-free cell-based assay is advantageous for biochemical study because of it does not require the use of experimental animals. Due to its ability ...

Imaging Amyloid Tissues Stained with Luminescent Conjugated Oligothiophenes by Hyperspectral Confocal Microscopy and Fluorescence Lifetime Imaging

Proteins that deposit as amyloid in tissues throughout the body can be the cause or consequence of a large number of diseases. Among these we find neurodegenerative diseases such as Alzheimer&#39;s and Parkinson&#39;s disease afflicting primarily the central nervous system, and systemic amyloidosis where serum amyloid A, transthyretin and IgG light chains deposit as amyloid in liver, carpal tunnel, spleen, kidney, heart, and other peripheral tissues. Amyloid has been known and studied for more than a century, often using amyloid specific dyes such as Congo red and Thioflavin T (ThT) or Thioflavin (ThS). In this paper, we present heptamer-formyl thiophene acetic acid (hFTAA) as an example of recently developed complements to these dyes called luminescent conjugated oligothiophenes (LCOs). hFTAA is easy to use and is compatible with co-staining in immunofluorescence or with other cellular markers. Extensive research has proven that hFTAA detects a wider range of disease associated protein aggregates than conventional amyloid dyes. In addition, hFTAA can also be applied for optical assignment of distinct aggregated morphotypes to allow studies of amyloid fibril polymorphism. While the imaging methodology applied is optional, we here demonstrate hyperspectral imaging (HIS), laser scanning confocal microscopy and fluorescence lifetime imaging (FLIM). These examples show some of the imaging techniques where LCOs can be used as tools to gain more detailed knowledge of the formation and structural properties of amyloids. An important limitation to the technique is, as for all conventional optical microscopy techniques, the requirement for microscopic size of aggregates to allow detection. Furthermore, the aggregate should comprise a repetitive &#946;-sheet structure to allow for hFTAA binding. Excessive fixation and/or epitope exposure that modify the aggregate structure or conformation can render poor hFTAA binding and hence pose limitations to accurate imaging.

Amyloid deposition is a hallmark of different diseases and afflicts many different organs. This paper describes the application of luminescent conjugated oligothiophene fluorescence staining in combination with fluorescence microscopy techniques. This staining method represents a powerful tool for detection and exploration of protein aggregates in both clinical and scientific setups.

Amiloid doku Imaging ile Işıksaçan konjuge Oligothiophenes Hyperspectral tarafından Confocal mikroskobu ve floresan ömür boyu görüntüleme lekeli

Proteins that deposit as amyloid in tissues throughout the body can be the cause or consequence of a large number of diseases. Among these we find ...

Use of Two Dimensional Semi-denaturing Detergent Agarose Gel Electrophoresis to Confirm Size Heterogeneity of Amyloid or Amyloid-like Fibers

Amyloid or amyloid-like fibers have been associated with many human diseases, and are now being discovered to be important for many signaling pathways. The ability to readily detect the formation of these fibers under various experimental conditions is essential for understanding their potential function. Many methods have been used to detect the fibers, but not without some drawbacks. For example, electron microscopy (EM), or staining with Congo Red or Thioflavin T often requires purification of the fibers. On the other hand, semi-denaturing detergent agarose gel electrophoresis (SDD-AGE) allows detection of the SDS-resistant amyloid-like fibers in the cell extracts without purification. In addition, it allows the comparison of the size difference of the fibers. More importantly, it can be used to identify specific proteins within the fibers by Western blotting. It is less time consuming and more easily accessible to a wider number of labs. SDD-AGE results often show variable degree of heterogeneity. It raises the question whether part of the heterogeneity results from the dissociation of the protein complex during the electrophoresis in the presence of SDS. For this reason, we have employed a second dimension of SDD-AGE to determine if the size heterogeneity seen in SDD-AGE is truly a result of fiber heterogeneity in vivo and not a result of either degradation or dissociation of some of the proteins during electrophoresis. This method allows fast, qualitative confirmation that the amyloid or amyloid-like fibers are not partially dissociating during the SDD-AGE process.

Here we use two-dimensional semi-denaturing agarose gel electrophoresis to confirm the presence of amyloid-like fibers of heterogeneous size and exclude the possibility that the size heterogeneity is due to dissociation of the amyloid fibers during the gel running process.

İki boyutlu yarı denaturing deterjan özel Jel Elektroforez amiloid veya amiloid benzeri liflerin boyutu heterojen onaylamak için kullanımı

Amyloid or amyloid-like fibers have been associated with many human diseases, and are now being discovered to be important for many signaling pathways. ...

A11-positive &#946;-amyloid Oligomer Preparation and Assessment Using Dot Blotting Analysis

&#946;-amyloid (A&#946;) is a hydrophobic peptide with an intrinsic tendency to self-assemble into aggregates. Among various aggregates, A&#946; oligomer is widely accepted as the leading neurotoxin in the progress of Alzheimer&#39;s disease (AD) and is considered to be the crucial event in the pathogenesis of AD. Therefore, A&#946; oligomer inhibitors might prevent neurodegeneration and have the potential to be developed as disease-modifying treatments of AD. However, different formation protocols of A&#946; oligomer might lead to oligomers with different characteristics. Moreover, there are not many methods to effectively screen A&#946;1-42 oligomer inhibitors. An A11 antibody can react with a subset of toxic A&#946;1-42 oligomer with anti-parallel &#946;-sheet structures. In this protocol, we describe how to prepare an A11-positive A&#946;1-42 oligomer-rich sample from a synthetic A&#946;1-42 peptide in vitro and to evaluate relative amounts of A11-positive A&#946;1-42 oligomer in samples by a dot blotting analysis using A11 and A&#946;1-42-specific 6E10 antibodies. Using this protocol, inhibitors of A11-positive A&#946;1-42 oligomer can also be screened from semi-quantitative experimental results.

This protocol describes how to prepare A&#946; oligomers from a synthetic peptide in vitro and to evaluate relative amounts of A&#946; oligomer by a dot blotting analysis.

A11-pozitif β-amiloid Oligomer hazırlama ve değerlendirme sistemini kullanarak Dot Blot Analizi

&#946;-amyloid (A&#946;) is a hydrophobic peptide with an intrinsic tendency to self-assemble into aggregates. Among various aggregates, A&#946; oligomer ...

Functional Characterization of Carboxylesterases in Insecticide Resistant House Flies, Musca Domestica

Carboxylesterase-mediated metabolism is thought to play a major role in insecticide resistance in various insects. Several carboxylesterase genes were found up-regulated in the resistant house fly strain, whereas their roles in conferring insecticide resistance remained to be explored. Here, we designed a protocol for the functional characterization of carboxylesterases. Three example experiments are presented: (1) expression and isolation of carboxylesterase proteins through a baculovirus-mediated insect Spodoptera frugiperda (Sf9) cell expression system; (2) a cell-based MTT (3-[4, 5-dimethykthiazol-2-yl]-2, 5-diphenyltetrazolium bromide) cytotoxicity assay to measure the tolerance of insect cells to different permethrin treatments; and (3) in vitro metabolic studies to explore the metabolic capabilities of carboxylesterases toward permethrin. The carboxylesterase gene Md&#945;E7 was cloned from a resistant house fly strain ALHF and used to construct a recombinant baculovirus for Sf9 cells infection. The cell viabilities against different permethrin treatments were measured with the MTT assay. The enhanced cell tolerance of the experimental group (Md&#945;E7-recombinant baculovirus infected cells) compared with those of the control groups (CAT-recombinant baculovirus infected cells and GFP-recombinant baculovirus infected cells) to permethrin treatments suggested the capabilities of Md&#945;E7 in metabolizing insecticides, thereby protecting cells from chemical damages. Besides that, carboxylesterase proteins were expressed in insect Sf9 cells and isolated to conduct an in vitro metabolic study. Our results indicated a significant in vitro metabolic efficiency of Md&#945;E7 toward permethrin, directly indicating the involvement of carboxylesterases in metabolizing insecticides and thus conferring insecticide resistance in house flies.

Functional Characterization of Carboxylesterases in Insecticide Resistant House Flies, Musca Domestica

Here, we present a protocol to produce house fly carboxylesterase proteins in vitro with a baculovirus mediated insect cell expression system and later functionally characterize their roles in metabolizing permethrin, thereby, conferring pyrethroid resistance by conducting cell-based MTT assay and in vitro metabolic studies.

Carboxylesterases böcek ilacı dayanıklı ev sinekleri, sinek Domestica içinde işlevsel karakterizasyonu

Carboxylesterase-mediated metabolism is thought to play a major role in insecticide resistance in various insects. Several carboxylesterase genes were ...

Analysis of &#946;-Amyloid-induced Abnormalities on Fibrin Clot Structure by Spectroscopy and Scanning Electron Microscopy

This article presents methods for generating in vitro fibrin clots and analyzing the effect of beta-amyloid (A&#946;) protein on clot formation and structure by spectrometry and scanning electron microscopy (SEM). A&#946;, which forms neurotoxic amyloid aggregates in Alzheimer&#39;s disease (AD), has been shown to interact with fibrinogen. This A&#946;-fibrinogen interaction makes the fibrin clot structurally abnormal and resistant to fibrinolysis. A&#946;-induced abnormalities in fibrin clotting may also contribute to cerebrovascular aspects of the AD pathology such as microinfarcts, inflammation, as well as, cerebral amyloid angiopathy (CAA). Given the potentially critical role of neurovascular deficits in AD pathology, developing compounds which can inhibit or lessen the A&#946;-fibrinogen interaction has promising therapeutic value. In vitro methods by which fibrin clot formation can be easily and systematically assessed are potentially useful tools for developing therapeutic compounds. Presented here is an optimized protocol for in vitro generation of the fibrin clot, as well as analysis of the effect of A&#946; and A&#946;-fibrinogen interaction inhibitors. The clot turbidity assay is rapid, highly reproducible and can be used to test multiple conditions simultaneously, allowing for the screening of large numbers of A&#946;-fibrinogen inhibitors. Hit compounds from this screening can be further evaluated for their ability to ameliorate A&#946;-induced structural abnormalities of the fibrin clot architecture using SEM. The effectiveness of these optimized protocols is demonstrated here using TDI-2760, a recently identified A&#946;-fibrinogen interaction inhibitor.

Presented here are two methods that can be used individually or in combination to analyze the effect of beta-amyloid on fibrin clot structure. Included is a protocol for creating an in vitro fibrin clot, followed by clot turbidity and scanning electron microscopy methods.

β-amiloid-indüklenen anormallikler Fibrin pıhtısı yapısına spektroskopisi ve elektron mikroskobu tarama Analizi

This article presents methods for generating in vitro fibrin clots and analyzing the effect of beta-amyloid (A&#946;) protein on clot formation and ...

Interactions with and Membrane Permeabilization of Brain Mitochondria by Amyloid Fibrils

A growing body of evidence indicates that membrane permeabilization, including internal membranes such as mitochondria, is a common feature and primary mechanism of amyloid aggregate-induced toxicity in neurodegenerative diseases. However, most reports describing the mechanisms of membrane disruption are based on phospholipid model systems, and studies directly targeting events occurring at the level of biological membranes are rare. Described here is a model for studying the mechanisms of amyloid toxicity at the membrane level. For mitochondrial isolation, density gradient medium is used to obtain preparations with minimal myelin contamination. After mitochondrial membrane integrity confirmation, the interaction of amyloid fibrils arising from &#945;-synuclein, bovine insulin, and hen egg white lysozyme (HEWL) with rat brain mitochondria, as an in vitro biological model, is investigated. The results demonstrate that treatment of brain mitochondria with fibrillar assemblies can cause different degrees of membrane permeabilization and ROS content enhancement. This indicates structure-dependent interactions between amyloid fibrils and mitochondrial membrane. It is suggested that biophysical properties of amyloid fibrils and their specific binding to mitochondrial membranes may provide explanations for some of these observations.

Provided here is a protocol for investigating the interactions between native form, prefibrillar, and mature amyloid fibrils of different peptides and proteins with mitochondria isolated from different tissues and various areas of the brain.

Amiloid Fibrils ile Beyin Mitokondrisi ile Etkileşimler ve Membran Permeabilizasyonu

A growing body of evidence indicates that membrane permeabilization, including internal membranes such as mitochondria, is a common feature and primary ...