Production and characterization of biosurfactants from Bacillus licheniformis F2.2

A biosurfactant-producing strain, Bacillus licheniformis F2.2, was isolated from a fermented food in Thailand. The strain was capable of producing a new biosurfactant, BL1193, as well as two kinds of popular lipopeptide biosurfactants, plipastatin and surfactin. Mass spectrometry and FT-IR analysis indicated that BL1193 had a molecular mass of 1,193 Da with no peptide portion in the molecule. While plipastatin and surfactin were abundantly produced in a nutrient YPD medium, BL1193 was produced only in a synthetic DF medium containing no amino acids. According to an oil displacement activity test, the specific activity of BL1193 (6.53 kBS units/mg) is equivalent to that of surfactin (5.78-6.83 kBS units/mg).     

Cell wall changes involved in the automorphic curvature of rice coleoptiles under microgravity conditions in space

Seedlings of rice (Oryza sativa L. cv. Koshihikari and cv. Tan-ginbozu) were cultivated on board the Space Shuttle STS-95 mission and changes in the morphology and the cell wall properties of coleoptiles were analyzed. In space, rice coleoptiles showed a spontaneous (automorphic) curvature toward the caryopsis in the elongating region. The angle of automorphic curvature was larger in Koshihikari than in a gibberellin-deficient dwarf cultivar, Tan-ginbozu, and the angle gradually decreased during the growth of coleoptiles in both cultivars. The more quickly expanding convex side of the bending region of the rice coleoptiles showed a greater extensibility of the cell wall than the opposite side. There was a significant correlation between the angle of curvature and the difference in the cell wall extensibility between the convex and the concave sides. Both the levels of the cell wall polysaccharides per unit length of coleoptile and the ratio of high-molecular-mass polysaccharides in the hemicellulose fraction were lower in the convex side than the concave one. Also, the activity of (13),(14)--glucanases in the cell wall was higher in the convex side than the concave one. These results suggest that the uneven modifications of cell wall metabolism bring about the difference in the levels and the molecular size of the cell wall polysaccharides, thereby causing the difference in capacity of the cell wall to expand between the dorsal and the ventral sides, leading to the automorphic curvature of rice coleoptiles in space. The data also suggest the involvement of gibberellins in inducing the automorphic curvature under microgravity conditions.     

Impulsive choice in inbred strains of mice

When humans or non-humans are given a choice between receiving a sooner-smaller (SS) reinforcer, or a later-larger (LL) reinforcer, the choice of a SS reinforcer represents impulsive choice whereas the choice of a LL reinforcer represents self-controlled choice. It has been suggested that both biological and genetic factors influence impulsive/self-control choice in this paradigm. In the present study, the inbred strains of BALB/c, C57BL/6, and DBA/2 mice were given a choice to press one of two levers in an operant chamber. Depending on their choice, mice received either a smaller reinforcer (one pellet delivered after 6s) sooner (SS) or a larger reinforcer (two pellets after 6, 9, 12, 18, or 30s) later (LL). Mice preference for the larger reinforcer decreased with longer delays. More importantly, the BALB/c mice chose the SS reinforcer more often than the C57BL/6 mice under the 9- and 12-s delays, and more often than the DBA/2 mice under the 9-s delay. This indicates that the choice pattern of the BALB/c strain is more "impulsive" than the other strains and suggests that specific gene configurations influence impulsive choice in mice.     

Characterization of electro-olfactogram oscillations and their computational reconstruction

Electro-olfactogram (EOG) oscillations induced by odorant stimulation have been often reported in various vertebrates from fishes to mammals. However, the mechanism of generation of EOG oscillations remains unclear. In the present study, we first characterized the properties of EOG oscillations induced by amino acid odorants in the rainbow trout and then performed a computer simulation based on the main assumption that olfactory receptor neurons (ORNs) have intrinsic oscillatory properties due to two types of voltage-gated ion channels, which have not yet been reported in vertebrate ORNs. EOG oscillations appeared mostly on the peak and decay phases of negative EOG responses, when odorant stimuli at high intensity flowed regularly anterior to posterior olfactory lamellae in the olfactory organ. The appearance of EOG oscillations was dependent on the odorant intensity but not on the flow rate. The maximum amplitude and the maximum power frequency of EOG oscillations were 3.51 +/- 3.35 mV (mean +/- SD, n = 232, range 0.12-16.79 mV) and 10.59 +/- 5.05 Hz (mean +/- SD, n = 232, range 3.51-40.03 Hz), respectively. The simulation represented sufficiently well the characteristics of EOG oscillations; occurrence at high odorant concentration, odorant concentration-dependent amplitude and the maximum power frequency range actually observed. Our results suggest that EOG oscillations are due to the intrinsic oscillatory properties of individual ORNs, which have two novel types of voltage-gated ion channels (resonant and amplifying channels). The simulation program for Macintosh ('oscillation 3.2.4' for MacOS 8.6 or later) is available on the world wide web (http://bio2.sci.hokudai.ac.jp/bio/chinou1/noriyo_home.html).     

Vasopressin phosphorylates HSP27 in aortic smooth muscle cells

Administration of arginine vasopressin (AVP) time-dependently induced the phosphorylation of heat shock protein 27 (HSP27) at Ser-15 and Ser-85 in smooth muscle of aorta in vivo. The AVP-induced phosphorylation of HSP27 at Ser-15 and Ser-85 was inhibited by a V1a receptor antagonist but not by a V2 receptor antagonist. In cultured aortic smooth muscle A10 cells, AVP markedly stimulated the phosphorylation of HSP27 at Ser-15 and Ser-85. The AVP-induced phosphorylation of HSP27 was attenuated by SB203580 and PD169316, inhibitors of p38 mitogen-activated protein (MAP) kinase, but not by PD98059, a MEK inhibitor. These results strongly suggest that AVP phosphorylates HSP27 via p38 MAP kinase in aortic smooth muscle cells.     

Xyloglucan oligosaccharides cause cell wall loosening by enhancing xyloglucan endotransglucosylase/hydrolase activity in azuki bean epicotyls

Addition of xyloglucan-derived oligosaccharides shifted the wall-bound xyloglucans to a lower molecular mass distribution and increased the cell wall extensibility of the native epidermal tissue strips isolated from azuki bean (Vigna angularis) epicotyls. To ascertain the mechanism of oligosaccharide function, we examined the action of a xyloglucan endotransglucosylase/hydrolase (XTH) showing both endotransglucosylase and endohydrolase activities, isolated from azuki bean epicotyl cell walls, in the presence of xyloglucan oligosaccharides. The addition of xyloglucan oligosaccharides enhanced the xyloglucan-degrading activity of XTH against isolated xyloglucan substrates. When the methanol-fixed epidermal tissue strips were incubated with XTH, the molecular mass of wall-bound xyloglucans was decreased and the cell wall extensibility increased markedly in the presence of the oligosaccharides. These results suggest that xyloglucan oligosaccharides stimulate the degradation of xyloglucans by enhancing the XTH activity within the cell wall architecture, thereby increasing the cell wall extensibility in azuki bean epicotyls.     

SCA8 repeat expansion: large CTA/CTG repeat alleles are more common in ataxic patients,including those with SCA6

We analyzed the SCA8 CTA/CTG repeat in a large group of Japanese subjects. The frequency of large alleles (85-399 CTA/CTG repeats) was 1.9% in spinocerebellar ataxia (SCA), 0.4% in Parkinson disease, 0.3% in Alzheimer disease, and 0% in a healthy control group; the frequency was significantly higher in the group with SCA than in the control group. Homozygotes for large alleles were observed only in the group with SCA. In five patients with SCA from two families, a large SCA8 CTA/CTG repeat and a large SCA6 CAG repeat coexisted. Age at onset was correlated with SCA8 repeats rather than SCA6 repeats in these five patients. In one of these families, at least one patient showed only a large SCA8 CTA/CTG repeat allele, with no large SCA6 CAG repeat allele. We speculate that the presence of a large SCA8 CTA/CTG repeat allele influences the function of channels such as alpha(1A)-voltage-dependent calcium channel through changing or aberrant splicing, resulting in the development of cerebellar ataxia, especially in homozygous patients.     

Determination of sugar phosphates and nucleotides related to photosynthetic metabolism by high-performance anion-exchange liquid chromatography with fluorometric and ultraviolet detection

A high-performance anion-exchange liquid chromatography system was constructed to identify sugar phosphates and nucleotides involved in photosynthetic metabolism. First sugar phosphates and nucleotides were separated by a gradient elution with boric acid and sodium phosphate, then they were detected by a fluorescence detector (as fluorescent derivatives with arginine) and UV detector, respectively. Eight authentic sugar phosphates and 11 authentic nucleotides could be analyzed using the system. The applicability of the system to the determination of the corresponding sugar phosphates and nucleotides in extracts from only five soybean leaf discs (8.95 cm2) was shown.