Bioreductive deposition of platinum nanoparticles on the bacterium Shewanella algae

An environmentally friendly method using the metal ion-reducing bacterium Shewanella algae was proposed to deposit platinum nanoparticles. Resting cells of S. algae were able to reduce aqueous PtCl(6)(2-) ions into elemental platinum at room temperature and neutral pH within 60min when lactate was provided as the electron donor. Biogenic platinum nanoparticles of about 5nm were located in the periplasm--a preferable, cell surface location for easy recovery of biogenic nanoparticles.     

Caf1 regulates translocation of ribonucleotide reductase by releasing nucleoplasmic Spd1-Suc22 assembly

Appropriate supply of deoxyribonucleotides by the ribonucleotide reductase (RNR) complex is essential for DNA replication and repair. One recent model for the RNR activation in Schizosaccharomyces pombe is translocation of the regulatory subunit Suc22 from the nucleoplasm to the cytoplasm. The RNR inhibitory protein Spd1, which retains Suc22 in the nucleoplasm, is rapidly degraded upon DNA-replication stress, resulting in release of Suc22 to form the active RNR complex in the cytoplasm. Here, we show that Caf1, a component of the Ccr4–Not complex, is responsible for resistance of the replication stress and control of the Suc22 translocation. Caf1 is required not only for the stress-induced translocation of Suc22 from nucleoplasm to cytoplasm but also for the degradation of nucleoplasmic Spd1. DNA-replication stress appears to allow Caf1 to interact with Suc22, resulting in release of the nucleoplasmic Spd1–Suc22 assembly. Taken together, these results suggest a novel function of Caf1 as a key regulator in the stress-induced RNR activation.     

Inhibition of NF-{kappa}B improves left ventricular remodeling and cardiac dysfunction after myocardial infarction

Several studies have demonstrated that NF-kappaB is substantially involved in the progression of cardiac remodeling; however, it remains uncertain whether the continuous inhibition of NF-kappaB is effective for the prevention of myocardial remodeling. Myocardial infarction (MI) was produced by ligation of the left anterior coronary artery of rats. IMD-0354 (10 mg/kg per day), a novel phosphorylation inhibitor of IkappaB that acts via inhibition of IKK-beta, was injected intraperitoneally starting 24 h after induction of MI for 28 days. After 28 days, the IMD-0354-treated group showed significantly improved survival rate compared with that of the vehicle-treated group (P < 0.05). Although infarct size was similar in both groups, improved left ventricular (LV) remodeling and diastolic dysfunction, as indicated by smaller LV cavity (LV end-diastolic area: vehicle, 74.13 +/- 3.57 mm(2); IMD-0354, 55.00 +/- 3.73 mm(2); P < 0.05), smaller peak velocity of early-to-late filling wave (E/A) ratio (vehicle, 3.87 +/- 0.26; IMD-0354, 2.61 +/- 0.24; P < 0.05), and lower plasma brain natriuretic peptide level (vehicle, 167.63 +/- 14.87 pg/ml; IMD-0354, 110.75 +/- 6.41 pg/ml; P < 0.05), were observed in the IMD-0354-treated group. Moreover, fibrosis, accumulation of macrophages, and expression of several factors (transforming growth factor-beta1, monocyte chemoattractant protein-1, matrix metalloproteinase-9 and -2) in the noninfarcted myocardium was remarkably inhibited by IMD-0354. In conclusion, inhibition of NF-kappaB activation may reduce the proinflammatory reactions and modulate the extracellular matrix and provide an effective approach to prevent adverse cardiac remodeling after MI.     

Chemistry,physiological properties,and microbial production of hydroxycitric acid

The tropical plants Garcinia cambogia and Hibiscus subdariffa produce hydroxycitric acid (HCA), of which the absolute configurations are (2S,3S) and (2S,3R), respectively. (2S,3S)-HCA is an inhibitor of ATP-citrate lyase, which is involved in fatty acid synthesis. (2S,3R)-HCA inhibits pancreatic α-amylase and intestinal α-glucosidase, leading to a reduction in carbohydrate metabolism. In this study, we review current knowledge on the structure, biological occurrence, and physiological properties of HCA. The availability of HCA is limited by the restricted habitat of its source plants and the difficulty of stereoselective organic synthesis. Hence, in our recent study, thousands of microbial strains were screened and finally two bacterial strains were, for the first time, found to produce trace amounts of HCA. The HCA variants produced were the Hibiscus-type (2S,3R) enantiomer. Subsequent genome shuffling rapidly generated a mutant population with improved HCA yield relative to the parent strain of bacteria. These bacteria are a potential alternative source of natural HCA.     

Insulin-induced impairment via peroxynitrite production of endothelium-dependent relaxation and sarco/endoplasmic reticulum Ca(2+)-ATPase function in aortas from diabetic rats

We designed this study to determine whether a high insulin level and a diabetic state need to exist together to cause an impairment of endothelium-dependent relaxation. In diabetic rat aortas organ-cultured with insulin [vs both control rat aortas cultured with insulin and diabetic rat aortas cultured in serum-free medium]: (1) the relaxation responses to both acetylcholine (endothelium-dependent relaxation) and Angeli's salt (nitric oxide donor) were significantly weaker, (2) acetylcholine-stimulated nitric oxide production was significantly smaller, (3) superoxide and nitric oxide production into the culture medium was greater, and (4) the levels of both nitrotyrosine and tyrosine-nitrated sarco/endoplasmic reticulum calcium ATPase (SERCA) protein were greater. The insulin-induced effects were prevented by cotreatment with either a superoxide scavenger or a peroxynitrite scavenger. After preincubation with an irreversible SERCA inhibitor, the relaxation induced by the nitric oxide donor was significantly impaired in control aortas cultured with or without insulin and in diabetic aortas cultured without insulin, but not in diabetic aortas cultured with insulin. These results suggest that the coexistence of a high insulin level and an established diabetic state may lead to an excessive generation of peroxynitrite, and that this may in turn trigger an impairment of endothelium-dependent relaxation via a decrease in SERCA function.     

RNAi gene silencing using cerasome as a viral-size siRNA-carrier free from fusion and cross-linking

Surface-rigidified cerasomes (ceramic-coated liposomes) are neither fused nor cross-linked when bound to siRNA (short duplex RNA) but not to plasmid DNA (long duplex DNA) which induces cross-linking. Non-ceramic reference liposomes are easily fused by the siRNA. The cerasome can thus be used as a viral-size siRNA-carrier in a wide range of concentration for RNAi silencing of exogenous and endogenous genes.     

Antitumor anthraquinones from an endophytic actinomycete Micromonospora lupini sp. nov

Two novel anthraquinones, lupinacidins A (1) and B (2), have been isolated from the culture broth of a new endophytic actinomycete belonging to the genus Micromonospora. Lupinacidins were found to show significant inhibitory effects on the invasion of murine colon 26-L5 carcinoma cells without inhibiting cell growth.     

Preservation of ejaculated mouse spermatozoa from fertile C57BL/6 and infertile Hook1/Hook1 mice collected from the uteri of mated females

Methods routinely used to preserve mouse spermatozoa require that the male be killed to recover spermatozoa from the epididymides. Here we obtained multiple samples of ejaculated spermatozoa from normal fertile C57BL/6 and infertile Hook1/Hook1 (formerly known as azh/azh) mutant males from uteri after mating, thus avoiding termination of the males. Ejaculated sperm were preserved by conventional cryopreservation or by rapid freezing without cryoprotection, and were injected into the oocytes by intracytoplasmic sperm injection (ICSI). The proportions of oocytes that survived, became activated, and developed into two-cell embryos were similar when comparing the two preservation methods in wild-type versus Hook1/Hook1 mice and tested mice versus controls (fresh and rapid-frozen epididymal and fresh ejaculated sperm). Two-cell embryos were transferred into the oviducts of pseudopregnant females, and fetal development was examined at Day 15 of gestation. A total of 39%-54% of transferred embryos produced with preserved ejaculated sperm implanted. Live, normal fetuses (11%-17%) were obtained in all examined groups and from all males included in the study. More implants (71%-82%) and fetuses (28%-31%) were noted in controls. Lower developmental potentials of embryos produced with preserved ejaculated sperm might be due to their capacitation status; the majority of sperm retrieved from the uterus were capacitated. This study bears significance for the maintenance and distribution of novel mouse strains. The method is applicable for all types of mice, including those with male infertility syndromes. The sole requirement is that the male of interest is able to copulate and its ejaculate contains spermatozoa.     

Pressure stability of the alpha-helix structure in a de novo designed protein (alpha-l-alpha)(2) studied by FTIR spectroscopy

The pressure-induced structural changes of a de novo designed four-helix bundle protein, (alpha-l-alpha)(2), in aqueous solution have been investigated by FTIR spectroscopy. Changes in the amide I' band intensity show that pressure induces disruption of tertiary interactions and stabilizes the solvated alpha-helical form. This may suggest that the exposure of the hydrophobic core to the solvent by pressure is not a sufficient condition for pressure-induced unfolding of the alpha-helices of proteins.