Four-wave mixing signals from β-carotene and its n = 15 homologue

The third-order nonlinear optical responses of β-carotene and its homologue having a conjugation-double bond n = 15 have been investigated using sub-20 fs ultra-short optical pulses in order to clarify the dissipation processes of excess energy. Using the four-wave mixing spectroscopy, we observed a clear coherent oscillation with a period of a few tens of femtoseconds. The spectral density of these molecules was estimated that allowed the theoretical linear and nonlinear optical signals to be directly compared with the experimental data. Calculations based on the Brownian oscillator model were performed under the impulsive excitation limit. We show that the memory of the vibronic coherence generated upon the excitation into the S₂ state is lost via the relaxation process including the S₁ state. The vibronic decoherence lifetime of the system was estimated to be 1 ps, which is about 5 times larger than the life time of the S₂ state (∼150 fs) determined in previous studies. The role of coherence and the efficient energy transfer in the light-harvesting antenna complexes are discussed.     

The structure and functions of NPM1/Nucleophsmin/B23, a multifunctional nucleolar acidic protein

NPM1/Nucleophosmin/B23, also termed NO38 or numatrin, is an acidic nucleolar protein that plays multiple roles in cell growth and proliferation. In general, the expression level of B23 is proportional to the cell growth rate, suggesting that it plays a positive role(s) in cell growth and proliferation. It is important to note that the deletion of the B23 gene and expression of an aberrant type of this gene--caused by gene conversion via translocation or reading-frame shift via nucleotides insertion-have been observed in diverse haematopoietic malignancies. Thus, it is important to understand the function of B23 in the regulation of cell growth and proliferation. In addition, B23 has been reported to undergo a variety of post-translational modifications such as phosphorylation, ubiquitination, SUMOylation, acetylation and poly-(ADP-ribosyl)ation. In this review, the basic structure and functions of B23 as well as the regulation of these functions are summarized.     

Endothelium-dependent vasorelaxation effect of rutin-free tartary buckwheat extract in isolated rat thoracic aorta

The aim of this study was to point out the potential of tartary buckwheat on vascular functions. A nonabsorbed fraction of hot-water extract of tartary buckwheat on a SP70 column (TBSP-T), which was free from rutin, was used for this aim. In a contractile experiment using Sprague-Dawley rat thoracic aorta rings contracted by 1.0 microM phenylephrine (PE) or 50 mM KCl, TBSP-T evoked a significant vasorelaxation [EC50 (mg/ml): PE; 2.2; KCl, 1.9]. By a further fractionation of TBSP-T by liquid-liquid partitioning into basic, neutral and acidic fractions, a marked enhancement of vasorelaxation effect was observed only for acidic fraction (EC50, 0.25 mg/ml). The action of acidic fraction was significantly attenuated in endothelium-denuded aortic rings and in the presence of nitric oxide synthase inhibitor, NG-monomethyl-L-arginine (100 microM). The fraction also enhanced the cyclic guanosine monophosphate (cGMP) production in aortic rings contracted with PE [cGMP (pmol/mg protein): PE, 7.2+/-2.3; PE+Acidic fraction, 35+/-8]. These results indicate that acidic fraction could mediate NO/cGMP pathways, thereby exerting endothelium-dependent vasorelaxation action. In conclusion, tartary buckwheat was proven to regulate vascular tones and have latent acidic candidates except for rutin.     

Extraction of protein and amino acids from deoiled rice bran by subcritical water hydrolysis

This study investigated the production of value-added protein and amino acids from deoiled rice bran by hydrolysis in subcritical water (SW) in the temperature range between 100 and 220 degrees C for 0-30 min. The results suggested that SW could effectively be used to hydrolyze deoiled rice bran to produce useful protein and amino acids. The amount of protein and amino acids produced are higher than those obtained by conventional alkali hydrolysis. The yields generally increased with increased temperature and hydrolysis time. However, thermal degradation of the product was observed when hydrolysis was carried out at higher temperature for extended period of time. The highest yield of protein and amino acids were 219 +/- 26 and 8.0 +/- 1.6 mg/g of dry bran, and were obtained at 200 degrees C at hydrolysis time of 30 min. Moreover, the product obtained at 200 degrees C after 30 min of hydrolysis exhibited high antioxidant activity and was shown to be suitable for use as culture medium for yeast growth.     

Rat mutations cvd and hob with cerebellar malformations map to chromosome 2.

In this paper, we executed genome mapping and comparative mapping analyses for cvd and hob, autosomal recessive mutations with cerebellar vermis defect and cerebellar dysplasia in the rat. For the linkage analysis, we produced three sets of backcross progeny, (ACI x CVD)F(1) and (F344 x CVD)F(1) females crossed to a cvd homozygous male rat, and (HOB x WKY)F(1) males crossed to hob homozygous female rats. Analysis of the segregation patterns of simple sequence length polymorphism (SSLP) markers scanning the whole rat genome allowed the mapping of these autosomal recessive mutations to rat Chromosome (Chr) 2. The most likely gene order is D2Mgh12 - D2Rat86 - D2Mit15 - D2Rat185 - cvd - D2Rat66 - D2Mgh13, and D2Mit18 - Fga -D2Mit14 - D2Rat16 - hob - D2Mgh13. Crossing test between a proven cvd heterozygous and a hob heterozygous rats demonstrated their allelism. Furthermore, comparative mapping indicated the cvd locus corresponds to mouse chromosome 3 and a strong candidate gene Unc5h3, a causative gene for the rostral cerebellar malformation mouse, was implicated.     

Possible involvement of an FKBP family member protein from a psychrotrophic bacterium Shewanella sp. SIB1 in cold-adaptation.

A psychrotrophic bacterium Shewanella sp. strain SIB1 was grown at 4 and 20 degrees C, and total soluble proteins extracted from the cells were analyzed by two-dimensional polyacrylamide gel electrophoresis. Comparison of these patterns showed that the cellular content of a protein with a molecular mass of 28 kDa and an isoelectric point of four greatly increased at 4 degrees C compared to that at 20 degrees C. Determination of the N-terminal amino acid sequence, followed by the cloning and sequencing of the gene encoding this protein, revealed that this protein is a member of the FKBP family of proteins with an amino acid sequence identity of 56% to Escherichia coli FKBP22. This protein was overproduced in E. coli in a His-tagged form, purified, and analyzed for peptidyl-prolyl cis-trans isomerase activity. When this activity was determined by the protease coupling assay using N-succinyl-Ala-Leu-Pro-Phe-p-nitroanilide as a substrate at various temperatures, the protein exhibited the highest activity at 10 degrees C with a k(cat)/K(m) value of 0.87 micro m(-1) x s(-1). When the peptidyl-prolyl cis-trans isomerase activity was determined by the RNase T(1) refolding assay at 10 and 20 degrees C, the protein exhibited higher activity at 10 degrees C with a k(cat)/K(m) value of 0.50 micro m(-1) x s(-1). These k(cat)/K(m) values are lower but comparable to those of E. coli FKBP22. We propose that a FKBP family protein is involved in cold-adaptation of psychrotrophic bacteria.     

Biotransformation of (+)-catechin into taxifolin by a two-step oxidation: primary stage of (+)-catechin metabolism by a novel (+)-catechin-degrading bacteria, Burkholderia sp. KTC-1, isolated from tropical peat

Peat contains various persistent compounds derived from plant materials. We isolated a novel (+)-catechin-degrading bacterium, Burkholderia sp. KTC-1 (KTC-1), as an example of a bacterium capable of degrading persistent aromatic compounds present in tropical peat. This bacterium was isolated by an enrichment technique and grew on (+)-catechin as the sole carbon source under acidic conditions. The reaction of a crude enzyme extract and a structural study of its products showed that (+)-catechin is biotransformed into taxifolin during the preliminary stages of its metabolism by KTC-1. HPLC analysis showed that this transformation occurs in two oxidation steps: 4-hydroxylation and dehydrogenation. Furthermore, both (+)-catechin 4-hydroxylanase and leucocyanidin 4-dehydrogenase were localized in the cytosol of KTC-1. This is the first report on biotransformation of (+)-catechin into taxifolin via leucocyanidin by an aerobic bacterium. We suggest that tropical peat could become a unique resource for microorganisms that degrade natural aromatic compounds.     

Effects of PAX3-FKHR on malignant phenotypes in alveolar rhabdomyosarcoma

The malignancy of alveolar rhabdomyosarcoma (ARMS) has been linked to expression of the PAX3-FKHR chimeric gene. To understand the effect of this gene, we used RNAi to knock down its expression (without affecting the expressions of either PAX3 or FKHR) in human ARMS cell lines. Down-regulating PAX3-FKHR caused (a) tumor cells to accumulate in the G1 phase, inhibiting the rate of cellular proliferation, (b) a reduction in the levels of the MET, reducing cell motility stimulated by HGF, and (c) induction of the myogenic differentiation gene, myogenin, and muscle differentiation (morphologic change and the expression of muscle specific proteins, desmin, and myosin heavy chain). These results suggest that PAX3-FKHR in ARMS cells promotes malignant phenotypes such as proliferation, motility, and to suppress differentiation.     

Interaction of TIP26 from a hyperthermophilic archaeon with TFB/TBP/DNA ternary complex

Interactions of TBP-interacting protein (TIP26), TBP, and TFB from a hyperthermophilic archaeon Thermococcus kodakaraensis KOD1 with TATA-DNA were examined by electrophoretic mobility shift assay. Tk-TFB formed a ternary complex with Tk-TBP and TATA-DNA. Tk-TIP26 did not inhibit the formation of this ternary complex, but interacted with it to form a TIP26/TFB/TBP/DNA quaternary complex. This interaction is rather weak, and a large excess of Tk-TIP26 over Tk-TBP is required to fully convert the TFB/TBP/DNA ternary complex to the quaternary complex. However, determination of the concentration of Tk-TIP26 and Tk-TBP in KOD1 cells by Western blotting analysis indicated that the concentration of Tk-TIP26 is approximately ten times that of Tk-TBP, suggesting that the quaternary complex might also form in vivo.