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Silver ions as em marker of congo red ligation sites in amyloids and amyloid-like aggregates

100%

Rybarska J., Konieczny L., Jagusiak A., Chłopaś K., Zemanek G., Piekarska B., Stopa B., Piwowar P., Woźnicka O., Roterman I.

2017

vol. 64

issue 1

161-169

Congo red (CR) is a known selective amyloid ligand. The focus of our work is identification (by EM imaging) of dye binding sites and their distribution in amyloids and amyloid-like aggregates formed in vitro. In order to produce the required contrast, CR has been indirectly combined with metal via including Titan yellow (TY) by intercalation which exhibits a relatively strong affinity for silver ions. The resulting combined ligand retains its ability to bind to proteins (which it owes to CR) and can easily be detected in EM studies thanks to TY. We have found, however, that in protein aggregates where unfolding is stabilized by aggregation and therefore is irreversible, TY alone may serve as both, the ligand and the metal carrier. The formation of ordered structures in amyloids was studied using IgG light chains with amyloidogenic properties, converted into amyloids by shaking. The resulting EM images were subjected to interpretation on the basis of the authors' earlier research on the CR/light chain complexation process. Our results indicate that dimeric light chains, which are the subject of our study, produce amyloids or amyloid-like complexes with chain-like properties and strong helicalization tendencies. Cursory analysis suggests that the edge polypeptide loops belonging to unstable light chains form intermolecular bridges which promote creation of loose gel deposits, or are otherwise engaged in the swapping processes leading to higher structural ordering.

Effect of diosgenin, a steroidal sapogenin, on the rat skeletal system

100%

Folwarczna J., Zych M., Nowińska B., Pytlik M., Bialik M., Jagusiak A., Lipecka-Karcz M., Matysiak M.

2016

vol. 63

issue 2

287-295

Diosgenin is a steroidal sapogenin present in fenugreek and Dioscorea spp. as glycosides (saponins). Diosgenin has already been reported to inhibit osteoclastogenesis and to stimulate osteogenic activity of osteoblastic cells in vitro, and to exert some antiosteoporotic effects in rats in vivo. The aim of the present study was to investigate the effects of diosgenin administration on the skeletal system of rats with normal estrogen level and with estrogen deficiency induced by bilateral ovariectomy. The experiments were carried out on 3-month-old non-ovariectomized and ovariectomized Wistar rats, divided into control rats and rats receiving diosgenin (50 mg/kg p.o. daily) for 4 weeks. Serum bone turnover markers, bone mass and mineralization, histomorphometric parameters and mechanical properties were studied. Diosgenin improved some investigated parameters in both non-ovariectomized and ovariectomized rats, in which estrogen deficiency induced osteoporotic changes. Diosgenin increased compact bone formation and probably inhibited cancellous bone resorption, which led to improvement of mechanical properties of compact and cancellous bone. In conclusion, this in vivo study demonstrated that diosgenin may be one of sparse compounds increasing bone formation.

Formation of amyloid-like aggregates through the attachment of protein molecules to a Congo red scaffolding framework ordered under the influence of an electric field

81%

Stopa B., Piekarska B., Konieczny L., Król M., Rybarska J., Jagusiak A., Spólnik P., Roterman I., Urbanowicz B., Piwowar P., Lewiński K.

Open Chemistry

2010

vol. 8

issue 1

41-50

This study describes a technique which makes it possible to introduce the amyloid-like order to protein aggregates by using the scaffolding framework built from supramolecular, fibrillar Congo red structures arranged in an electric field. The electric field was used not only to obtain a uniform orientation of the charged dye fibrils, but also to make the fibrils long, compact and rigid due to the delocalization of pi electrons, which favors ring stacking and, as a consequence, results in an increased tendency to self-assemble. The protein molecules (immunoglobulin L chain lambda, ferritin) attached to this easily adsorbing dye framework assume its ordered structure. The complex precipitating as plate-like fragments shows birefringence in polarized light. The parallel organization of fibrils can be observed with an electron microscope. The dye framework may be removed via reduction with sodium dithionite, leaving the aggregated protein molecules in the ordered state, as confirmed by X-ray diffraction studies. [...]

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2 Acta Biochimica Polonica

1 Open Chemistry

1 2017

1 2016

1 2010

3 Jagusiak A.

2 Konieczny L.

2 Piekarska B.

2 Piwowar P.

2 Roterman I.

2 Rybarska J.

2 Stopa B.

1 Bialik M.

1 Chłopaś K.

1 Folwarczna J.

1 Król M.

1 Lewiński K.

1 Lipecka-Karcz M.

1 Matysiak M.

1 Nowińska B.

1 Pytlik M.

1 Spólnik P.

1 Urbanowicz B.

1 Woźnicka O.

1 Zemanek G.

1 Zych M.

Search results

Silver ions as em marker of congo red ligation sites in amyloids and amyloid-like aggregates

Effect of diosgenin, a steroidal sapogenin, on the rat skeletal system

Formation of amyloid-like aggregates through the attachment of protein molecules to a Congo red scaffolding framework ordered under the influence of an electric field