Optical properties of amyloid stained by Congo red: History and mechanisms

Howie, Alexander J.; Brewer, D. B.

doi:10.1016/j.micron.2008.10.002

Cited by 176 publications

(143 citation statements)

References 29 publications

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“…Amyloid represents a fibrous cross-b sheet quaternary structure of ordered peptide or protein aggregates that demonstrate common biophysical properties [4]. Functional amyloids exhibit the same biophysical characteristics as pathogenic amyloids, including binding of the amyloidophilic dyes thioflavin T (ThT) and Congo red (CR) and characteristic coloured birefringence when stained with CR and viewed under cross-polarized light [5]. When viewed by electron microscopy (EM), amyloid fibres are 5-13 nm in diameter and range in length from a few nanometers to several micrometers [6].…”

Section: Introductionmentioning

confidence: 99%

Functional amyloids in Streptococcus mutans, their use as targets of biofilm inhibition and initial characterization of SMU_63c

et al. 2017

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Amyloids have been identified as functional components of the extracellular matrix of bacterial biofilms. Streptococcus mutans is an established aetiologic agent of dental caries and a biofilm dweller. In addition to the previously identified amyloidogenic adhesin P1 (also known as AgI/II, PAc), we show that the naturally occurring antigen A derivative of S. mutans wall-associated protein A (WapA) and the secreted protein SMU_63c can also form amyloid fibrils. P1, WapA and SMU_63c were found to significantly influence biofilm development and architecture, and all three proteins were shown by immunogold electron microscopy to reside within the fibrillar extracellular matrix of the biofilms. We also showed that SMU_63c functions as a negative regulator of biofilm cell density and genetic competence. In addition, the naturally occurring C-terminal cleavage product of P1, C123 (also known as AgII), was shown to represent the amyloidogenic moiety of this protein. Thus, P1 and WapA both represent sortase substrates that are processed to amyloidogenic truncation derivatives. Our current results suggest a novel mechanism by which certain cell surface adhesins are processed and contribute to the amyloidogenic capability of S. mutans. We further demonstrate that the polyphenolic small molecules tannic acid and epigallocatechin-3-gallate, and the benzoquinone derivative AA-861, which all inhibit amyloid fibrillization of C123 and antigen A in vitro, also inhibit S. mutans biofilm formation via P1-and WapA-dependent mechanisms, indicating that these proteins serve as therapeutic targets of anti-amyloid compounds.

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Section: Introductionmentioning

confidence: 99%

Functional amyloids in Streptococcus mutans, their use as targets of biofilm inhibition and initial characterization of SMU_63c

et al. 2017

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“…Besides the various shades of green and blue with polarization, all deposits not simultaneously showing polarization are defined as anomalous color change and this can be seen in pictures in the publications. Howie et al recently emphasized this (16)(17)(18). Our findings indicate that all deposits do not simultaneously show polarization on H&E polarization where the polarization is in typical apple green color and is less than the polarization with CR.…”

Section: Discussionmentioning

confidence: 44%

Digitally Reinforced Polarization of Hematoxylin-Eosin in the Diagnosis of Renal Amyloidosis

Şen

Kumbaraci²

2012

TJPATH

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Objective: Systemic amyloidosis is a rare disorder, characterized by extracellular accumulation of Congo red positive fibrillar amyloid protein deposits that have an amorphous, eosinophilic appearance on hematoxylin-eosin stained preparations. The kidney is the most commonly affected organ by systemic amyloidosis. Congo red staining increases the positive birefringence of the weakly birefringent unstained amyloid. In this study, we investigated the potential diagnostic power of digitally reinforced birefringence of routine hematoxylin-eosin stained slides from renal biopsies. Material and Method:We reviewed 130 hematoxylin-eosin stained slides for polarization. Sixty-five new amyloidosis cases were diagnosed by renal biopsy. All renal biopsies were evaluated by light microscopy and immunofluorescence. Slides were reevaluated blindly using a microscope (Olympus BX51) that was attached polarization filters and connected to a digital camera (Olympus DP21, SAL). Deposits that showed green birefringence on hematoxylin-eosin preparations with digitalized microscopy were considered positive and the results were confirmed using Congo red.Results: Of the 65 Congo red confirmed amyloid positive biopsies, 61 showed green birefringence with hematoxylin-eosin. Of the 65 Congo-red confirmed amyloid negative biopsies, two were considered to be false positive. The sensitivity, specificity, and positive and negative predictive values were estimated as 94%, 97%, 97% and 94% respectively. Conclusion:We concluded that polarized hematoxylin-eosin sections can be used digitally as a fast and first step diagnostic method for renal amyloidosis Key Words: Amyloid, Amyloidosis, Congo Red, Hematoxylin ÖZ Amaç: Sistemik amiloidozlar, hematoksilen-eozin boyamada amorf eozinofilik görülen, Kongo kırmızısı ile boyanan fibriller amiloid proteinlerin ekstrasellüler birikimiyle karakterize nadir hastalıklardır. Böbrekler sistemik amiloidozlardan en sık etkilenen organdır. Kongo kırmızısı, zayıf birefrenjant boyanmamış amiloidin birefranjansını artırır. Bu çalışmada, böbrek biopsilerinin rutin hematoksilen eozin kesitlerinde dijital güçlendirilmiş birefrenjansın potansiyel tanısal gücünü araştırdık. Gereç ve Yöntem:Hematoksilen-eozin boyalı 130 preparat polarizasyon için değerlendirildi. Altmış beş yeni amiloidoz olgusuna böbrek biyopsisi ile tanı konuldu. Tüm böbrek biopsileri ışık ve immünflöresan mikroskop ile değerlendirildi. Preparatlar kör olarak, polarizasyon filtreleri eklenmiş ve digital kamera (Olympus DP21, SAL) bağlanmış mikroskopla (Olympus BX51) değerlendirildi. Dijitalize mikroskopi ile yeşil birefrenjans gösteren birikimler pozitif olarak değerlendirildi ve Kongo kırmızısı ile birikimler doğrulandı. Bulgular: Kongo kırmızısı ile doğrulanmış 65 amiloid pozitif biopsinin 61'i hematoksilen-eozin ile yeşil birefrenjans gösterdi. Kongo kırmızısı ile doğrulanmış, 65 amiloid birikimi olmayan olgunun 2'si yalancı pozitif olarak değerlendirildi. Duyarlılık, özgüllük, pozitif ve negatif prediktif değerler sırasıyla %94, %97, %97 ve ...

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“…through heating [3]. Under natural conditions Congo red (CR) is spontaneously bound by partly unfolded proteins capable of forming aggregationssuch as amyloids and some abnormal [4][5][6][7][8][9]. While aberrant (unstable) proteins are usually eliminated before they can leave their parent cell [10][11][12][13], under certain circumstances -such as mass synthesis of light chains associated with multiple myeloma -they can be detected in circulation ( Fig.…”

Section: Natural Susceptibility Of Proteins To Bind Congo Redmentioning

confidence: 99%

Protein Conditioning for Binding Congo Red and Other Supramolecular Ligands

Zemanek

Jagusiak

Rybarska

et al. 2017

Self-Assembled Molecules – New Kind of Protein Ligands

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Self-assembled organic compounds which form ribbon-like micellar clusters may attach themselves to proteins, penetrating in areas of low stability. Such complexation involves regions other than the protein's natural binding site. The supramolecular ligand adheres to beta folds or random coils which become susceptible to complexation as a result of function-related structural changes -e.g. antibodies engaged in immune complexes or acute phase proteins. However, even seemingly unsusceptible helical proteins may bind Congo red if they include chameleon sequences (short peptide fragments capable of adopting different secondary conformations depending on environmental conditions). Examples of such proteins include hemoglobin and albumin. Complexation of supramolecular Congo red is often associated with increased fluorescence, indicating breakdown of ligand micelles in the complex. This phenomenon may be used in diagnostic tests. Keywords

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Optical properties of amyloid stained by Congo red: History and mechanisms

Cited by 176 publications

References 29 publications

Functional amyloids in Streptococcus mutans, their use as targets of biofilm inhibition and initial characterization of SMU_63c

Functional amyloids in Streptococcus mutans, their use as targets of biofilm inhibition and initial characterization of SMU_63c

Digitally Reinforced Polarization of Hematoxylin-Eosin in the Diagnosis of Renal Amyloidosis

Protein Conditioning for Binding Congo Red and Other Supramolecular Ligands

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