458 research outputs found
FHR-1 binds to C-reactive protein and enhances rather than inhibits complement activation
Factor H (FH)-related protein 1 (FHR-1) is one
of the five human factor H-related proteins,
which share sequence and structural homology
with the alternative pathway complement
inhibitor FH. Genetic studies on
disease associations and functional analyses indicate that
FHR-1 enhances complement activation by co
mpetitive inhibition of FH binding to some
surfaces and immune proteins. We have recen
tly shown that FHR-1 binds to pentraxin 3.
Here, our aim was to investigate whether FH
R-1 binds to another
pentraxin, C-reactive
protein (CRP), analyze the functional relevance
of this interaction and study the role of FHR-
1 in complement activation and regulation. FHR-
1 did not bind to native,
pentameric CRP but
it bound strongly to monomeric CRP via its C-term
inal domains. FHR-1 at high concentration
competed with FH for CRP binding, indicating
possible complement de
-regulation also on
this ligand. FHR-1 did not inhibi
t regulation of solid phase C3 convertase by FH and did not
inhibit terminal complement complex forma
tion induced by zymosan. On the contrary, by
binding C3b, FHR-1 allowed C3 convertase form
ation and thereby enhanced complement
activation. FHR-1/CRP interacti
ons increased complement activ
ation via the classical and
alternative pathways on surfaces such as th
e extracellular matrix and necrotic cells.
Altogether, these results identify CRP as a lig
and for FHR-1 and suggest
that FHR-1 enhances
rather than inhibits complement activation, wh
ich may explain the protective effect of FHR-1
deficiency in age-related macular degeneration
Vegetation history, recent dynamics and future prospects of a Hungarian sandy forest-steppe reserve: forest-grassland relations, tree species composition and size-class distribution
Pannonian forest-steppes host a high number of endemic species and contribute to landscape-scale heterogeneity. Alterations in the proportion of forests and grasslands due to changes in land-use practice and climatic parameters can have serious nature conservation consequences. Hypotheses about forest-steppe dynamics have rarely been verified by detailed analyses, especially for the sandy forest-steppes. We integrated historical analysis, aerial photo interpretation and field investigation to determine how vegetation of a sandy forest-steppe has changed, how current dynamical processes operate and how native and exotic tree species regenerate under present conditions. The vegetation of the study area before the onset of major anthropogenic environmental transformations in the Carpathian Basin may have been a mosaic of forested and unforested patches. However, there is strong evidence that after heavy deforestation, the region was almost completely treeless between the 15th and the 19th centuries. Forest cover was able to recover by the 1800s but the lack of forested areas in the region for centuries explains why forest patches are still poor in species. Grasslands, which existed continuously, are more diverse, supporting several rare and endemic species. From 1953 till 2013, 72.45% of the area proved to be stable, but 27.55% showed clear dynamical character, changing either from forest to grassland, or vice versa. Thus, cyclic dynamics can occur in sandy forest-steppes. We found that forest patches of different size, differently exposed edges and grasslands provide different habitats for the tree species. Exotic species were present in large numbers, probably due to the small size of the reserve and the lack of a buffer zone
Evaluation of Microwave Vacuum Drying Combined with Hot-Air Drying and Compared with Freeze- and Hot-Air Drying by the Quality of the Dried Apple Product
In this study, combined microwave vacuum drying (MVD) with hot-air drying was evaluated, and then compared with hot-air drying and freeze drying, by the quality of the created product. The aim was to show that MVD is a strong quality competitor with the conventional hot-air drying and the widely used, but expensive freeze drying. For raw material, Jonathan apple was used. The combined microwave vacuum drying consists of two steps, the hot-air pre-drying, and then the microwave vacuum drying. The MVD was made with a unique batch drying system. Chemical, (total phenolic compounds, free radical-scavenging activity, aromatic content) physical (hardness) and consumer-related (organoleptic, and microbiological) properties were measured as quality parameters. The results show that quality of the product made by MVD combined with hot-air pre-drying is higher than hot-air dried ones. By most of the measured quality parameters, microwave vacuum drying also provided higher quality product than freeze drying
A komplementrendszer aktiválódását gátló H-faktor és az FHR molekulák patológiás szerepének vizsgálata
Book reviews
Benders' dictionary of nutrition and food technology. D. A. BENDER and A. E. BENDER CRC Press, Boca Raton etc., Woodhead Publishing Ltd, Cambridge, 1999, ISBN Nos 0-8493-0018-5; 1 85573 475 3, 463 pages; International food safety handbook. Science, international regulation, and control. K. VAN DER HEIDEN, M. YOUNES, L. FISHBEIN and S. MILLER (Eds) Marcel Dekker, Inc., New York, Basel, 1999, ISBN No. 0-8247-9354-4, 811 page
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