A Large Scale Analysis of Protein–Protein Interactions in the Nitrogen-fixing Bacterium Mesorhizobium loti

Global viewing of protein–protein interactions (PPIs) is a useful way to assign biological roles to large numbers of proteins predicted by complete genome sequence. Here, we systematically analyzed PPIs in the nitrogen-fixing soil bacterium Mesorhizobium loti using a modified high-throughput yeast two-hybrid system. The aims of this study are primarily on the providing functional clues to M. loti proteins that are relevant to symbiotic nitrogen fixation and conserved in other rhizobium species, especially proteins with regulatory functions and unannotated proteins. By the screening of 1542 genes as bait, 3121 independent interactions involving 1804 proteins (24% of the total protein coding genes) were identified and each interaction was evaluated using an interaction generality (IG) measure and the general features of the interacting partners. Most PPIs detected in this study are novel interactions revealing potential functional relationships between genes for symbiotic nitrogen fixation and signal transduction. Furthermore, we have predicted the putative functions of unannotated proteins through their interactions with known proteins. The results described here represent new insight into protein network of M. loti and provide useful experimental clues to elucidate the biological function of rhizobial genes that can not be assigned directly from their genomic sequence

Genome Structure of the Legume, Lotus japonicus

The legume Lotus japonicus has been widely used as a model system to investigate the genetic background of legume-specific phenomena such as symbiotic nitrogen fixation. Here, we report structural features of the L. japonicus genome. The 315.1-Mb sequences determined in this and previous studies correspond to 67% of the genome (472 Mb), and are likely to cover 91.3% of the gene space. Linkage mapping anchored 130-Mb sequences onto the six linkage groups. A total of 10 951 complete and 19 848 partial structures of protein-encoding genes were assigned to the genome. Comparative analysis of these genes revealed the expansion of several functional domains and gene families that are characteristic of L. japonicus. Synteny analysis detected traces of whole-genome duplication and the presence of synteny blocks with other plant genomes to various degrees. This study provides the first opportunity to look into the complex and unique genetic system of legumes

ICRF Heating in CHS

ICRF heating experiments with five poloidal half-turn antennas have been carried out in Compact Helical System (CHS). These antennas designed for the inward shifted magnetic configuration (R_ax=92.1cm) were installed in the high field side of helical field. A high power RF pulse is applied to a deuterium plasma with hydrogen minority initiated by ECH or NBI. The plasma performance was mainly affected by the oxygen radiation which was reduced by more than 2 times by boronization. The plasma stored energy reached 2.2 kJ with 590 kW of RF power from 5 antennas and was sustained to the end of the RF pulse(60msec). Two-component ion energy spectrum was observed by NPA. The combined heating with NBI was also successful and achieved the increase in the stored energy of 0.8 kJ with 450 kW of RF power from 5 antennas

The carbonyl scavengers aminoguanidine and tenilsetam protect against the neurotoxic effects of methylglyoxal

Advanced glycation end products (AGEs) have been identified in age-related intracellular protein deposits of Alzheimer’s disease (amyloid plaques and neurofibrillary tangles) and Parkinson disease (Lewy bodies), suggesting that these protein deposits have been exposed to AGE precursors such as the reactive dicarbonyl compound methylglyoxal. In ageing tissue and under diabetic pseudohypoxia, intracellular methylglyoxal levels rise through an impairment of triosephosphate utilization. Furthermore, methylglyoxal detoxification is impaired when reduced glutathione levels are low, conditions, which have all been described in Alzheimer’s disease. However, there is less known about the toxicity of methylglyoxal, particularly about therapeutic strategies to scavenge such dicarbonyl compounds and attenuate their toxicity. In our study, extracellularly applied methylglyoxal was shown to be toxic to human neuroblastoma cells in a dose-dependent manner above concentrations of 150 µM with a LD50 of approximately 1.25 mM. Pre-incubation of methylglyoxal with a variety of carbonyl scavengers such as aminoguanidine or tenilsetam and the thiol antioxidant lipoic acid significantly reduced its toxicity. In summary, carbonyl scavengers might offer a promising therapeutic strategy to reduce the neurotoxicity of reactive carbonyl compounds, providing a potential benefit for patients with age-related neurodegenerative diseases