Synthesis,in vitro and in vivo studies of Gd-DTPA-XDA-D1-Glc(OH) complex as a new potential MRI contrast agent

A new type of dendritic molecules Gd-DTPA-XDA-D1-Glc(OH), which work as a functionalized ligand coordinating gadolinium(III) ion at the center of their frameworks with two glucose moieties on the molecular surfaces, were readily synthesized with high yield. The structures were established by IR, ¹H, ¹³C NMR, and mass spectral studies. Its bio-distribution patterns were evaluated on rats.     

Soy protein suppresses gene expression of acetyl-coA carboxylase alpha from promoter PI in rat liver

Dietary soy protein isolate (SPI) reduces hepatic lipogenesis by suppressing gene expression of lipogenic enzymes, including acetyl-CoA carboxylase (ACC). In order to elucidate the mechanism of this regulation, the effect of dietary SPI on promoter (PI and PII) specific gene expression of ACC alpha was investigated. Rats were fed experimental diets containing SPI or casein as a nitrogen source. SPI feeding decreased the hepatic contents of total ACC mRNA as well as triglyceride (TG) content, but dietary SPI affected the amount of sterol-regulatory element binding protein (SREBP)-1 mRNA and protein very little. The amount of ACC mRNA transcribed from PII promoter containing SRE was not significantly affected by dietary protein, while a significant decrease in PI-generated ACC mRNA content was observed in rats fed the SPI diet. These data suggest that SPI feeding decreased the hepatic contents of ACC alpha mRNA mainly by regulating PI promoter via a nuclear factor(s) other than SREBP-1.     

Structure of an archaeal homolog of the human protein complex Rpp21-Rpp29 that is a key core component for the assembly of active ribonuclease P

Ribonuclease P (RNase P) is a ribonucleoprotein complex involved in the processing of the 5′-leader sequence of precursor tRNA. Human RNase P protein subunits Rpp21 and Rpp29, which bind to each other, with catalytic RNA (H1 RNA) are sufficient for activating endonucleolytic cleavage of precursor tRNA. Here we have determined the crystal structure of the complex between the Pyrococcus horikoshii RNase P proteins PhoRpp21 and PhoRpp29, the archaeal homologs of Rpp21 and Rpp29, respectively. PhoRpp21 and PhoRpp29 form a heterodimeric structure where the two N-terminal helices (α1 and α2) in PhoRpp21 predominantly interact with the N-terminal extended structure, the β-strand (β2), and the C-terminal helix (α3) in PhoRpp29. The interface is dominated by hydrogen bonds and several salt bridges, rather than hydrophobic interactions. The electrostatic potential on the surface of the heterodimer shows a positively charged cluster on one face, suggesting a possible RNA-binding surface of the PhoRpp21-PhoRpp29 complex. The present structure, along with the result of a mutational analysis, suggests that heterodimerization between PhoRpp21 and PhoRpp29 plays an important role in the function of P. horikoshii RNase P.     

Effects of recombinant human macrophage colony-stimulating factor on atherosclerotic lesions established in the aorta of high cholesterol-fed rabbits

Anti-atherosclerotic effects of human macrophage colony-stimulating factor were investigated using rabbits fed a high cholesterol diet. Rabbits fed a diet containing 2% cholesterol for 59 days developed hyperlipidemia and atheromatous aortic plaques. They were then administered 80 microg/kg/day of either macrophage colony-stimulating factor or human serum albumin, as a control, for the next 12 weeks. Compared with the control group, rabbits treated with macrophage colony-stimulating factor had significantly fewer plaques on the inner surface of the thoracic and abdominal aortae, and half the sectional area of thickened intima in the aortic arch, as well as in the thoracic and abdominal aortae. Macrophage colony-stimulating factor also decreased the cholesterol content of the atherosclerotic lesions. Serobiochemical analyses revealed that macrophage colony-stimulating factor increased the levels of high density lipoprotein-cholesterol significantly, without influencing other lipid parameters such as the level of low density lipoproteins. The effects of macrophage colony-stimulating factor were evident until the fourth week of drug injection, at which time anti-human macrophage colony-stimulating factor antibodies were clearly induced in the serum. These results indicate that exogenously administered macrophage colony-stimulating factor suppresses atherosclerotic lesions induced by a high cholesterol diet by activating lipid metabolism in vivo.     

Immature Pacific bluefin tuna, <Emphasis Type="Italic">Thunnus orientalis</Emphasis>, utilizes cold waters in the Subarctic Frontal Zone for trans-Pacific migration

The habitat and movements of a Pacific bluefin tuna were investigated by reanalyzing archival tag data with sea surface temperature data. During its trans-Pacific migration to the eastern Pacific, the fish took a direct path and primarily utilized waters, in the Subarctic Frontal Zone (SFZ). Mean ambient temperature during the trans-Pacific migration was 14.5 ± 2.9 (°C ± SD), which is significantly colder than the waters typically inhabited by bluefin tuna in their primary feeding grounds in the western and eastern Pacific (17.6 ± 2.1). The fish moved rapidly through the colder water, and the heat produced during swimming and the thermoconservation ability of bluefin tuna likely enabled it to migrate through the cold waters of the SFZ.     

FTIR detection of structural changes in a histidine ligand during S-state cycling of photosynthetic oxygen-evolving complex

Changes in structural coupling between the Mn cluster and a putative histidine ligand during the S-state cycling of the oxygen-evolving complex (OEC) have been detected directly by Fourier transform infrared (FTIR) spectroscopy in photosystem (PS) II core particles from the cyanobacterium Synechocystis sp. PCC6803, in which histidine residues were selectively labeled with l-[(15)N(3)]histidine. The bands sensitive to the histidine-specific isotope labeling appeared at 1120-1090 cm(-)(1) in the spectra induced upon the first-, second-, and fourth-flash illumination, for the S(2)/S(1), S(3)/S(2), and S(1)/S(0) differences, at similar frequencies with different sign and/or intensity depending on the respective S-state transitions. However, no distinctive band was observed in the third-flash induced spectrum for the S(0)/S(3) difference. The results indicate that a single histidine residue coupled with the structural changes of the OEC during the S-state cycling is responsible for the observed histidine bands, in which the histidine modes changed during the S(0)-to-S(1) transition are reversed upon the S(1)-to-S(2) and S(2)-to-S(3) transitions. The 1186(+)/1178(-) cm(-)(1) bands affected by l-[(15)N(3)]histidine labeling were observed only for the S(2)/S(1) difference, but those affected by universal (15)N labeling appeared prominently showing a clear S-state dependency. Possible origins of these bands and changes in the histidine modes during the S-state cycling are discussed.