ABSTRACT
The in vitro and in vivo immunoregulatory activity of a water-soluble sulfated fucan AL1-1 from the sea cucumber A. leucoprocta was elucidated. In vitro experiments showed that AL1-1 up-regulated immunostimulatory activities in RAW264.7 cells and that it could successfully promote ROS production and phagocytic activity, increase secretion levels of iNOS, and induce the production of considerable amounts of cytokines (TNF-α, IL-6, IL-1ß and IL-12). We found that toll-like receptor 4 (TLR4) was mainly involved in AL1-1 mediated macrophage activation. AL1-1's in vivo immunomodulatory activity on cyclophosphamide (CY)-treated mice was investigated and it was shown that it could strongly enhance Sig A levels, promote the total antioxidant capacity (T-AOC), and reduce malondialdehyde (MDA) level in the intestine. It could also increase activities of superoxidase dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-PX). These results demonstrate that AL1-1 has a significant effect on enhancing in vivo and in vitro immune response.
Subject(s)
Immunity, Mucosal/drug effects , Immunomodulating Agents/pharmacology , Intestinal Mucosa/drug effects , Macrophage Activation/drug effects , Macrophages/drug effects , Polysaccharides/pharmacology , Sea Cucumbers , Animals , Antioxidants/metabolism , Cytokines/metabolism , Female , Free Radical Scavengers/isolation & purification , Free Radical Scavengers/pharmacology , Immunoglobulin A, Secretory/metabolism , Immunomodulating Agents/isolation & purification , Intestinal Mucosa/immunology , Intestinal Mucosa/metabolism , Macrophages/immunology , Macrophages/metabolism , Mice , Mice, Inbred ICR , Nitric Oxide Synthase Type II/metabolism , Phagocytosis/drug effects , Polysaccharides/isolation & purification , RAW 264.7 Cells , Reactive Oxygen Species/metabolism , Sea Cucumbers/chemistry , Toll-Like Receptor 4/metabolismABSTRACT
Assembly of eukaryotic ribosome is a complicated and dynamic process that involves a series of intermediates. It is unknown how the highly intertwined structure of 60S large ribosomal subunits is established. Here, we report the structure of an early nucleolar pre-60S ribosome determined by cryo-electron microscopy at 3.7 Å resolution, revealing a half-assembled subunit. Domains I, II and VI of 25S/5.8S rRNA pack tightly into a native-like substructure, but domains III, IV and V are not assembled. The structure contains 12 assembly factors and 19 ribosomal proteins, many of which are required for early processing of large subunit rRNA. The Brx1-Ebp2 complex would interfere with the assembly of domains IV and V. Rpf1, Mak16, Nsa1 and Rrp1 form a cluster that consolidates the joining of domains I and II. Our structure reveals a key intermediate on the path to establishing the global architecture of 60S subunits.
