Cloning and expression of the large zebrafish protocadherin gene, Fat

The cadherin superfamily members play an important role in mediating cell-cell contact and adhesion (Takeichi, M., 1991. Cadherin cell adhesion receptors as a morphogenetic regulator. Science 251, 1451-1455). A distinct subfamily, neither belonging to the classical or protocadherins includes Fat, the largest member of the cadherin super-family. Fat was originally identified in Drosophila. Subsequently, orthologues of Fat have been described in man (Dunne, J., Hanby, A. M., Poulsom, R., Jones, T. A., Sheer, D., Chin, W. G., Da, S. M., Zhao, Q., Beverley, P. C., Owen, M. J., 1995. Molecular cloning and tissue expression of FAT, the human homologue of the Drosophila fat gene that is located on chromosome 4q34-q35 and encodes a putative adhesion molecule. Genomics 30, 207-223), rat (Ponassi, M., Jacques, T. S., Ciani, L., ffrench, C. C., 1999. Expression of the rat homologue of the Drosophila fat tumour suppressor gene. Mech. Dev. 80, 207-212) and mouse (Cox, B., Hadjantonakis, A. K., Collins, J. E., Magee, A. I., 2000. Cloning and expression throughout mouse development of mfat 1, a homologue of the Drosophila tumour suppressor gene fat [In Process Citation]. Dev. Dyn. 217, 233-240). In Drosophila, Fat has been shown to play an important role in both planar cell polarity and cell boundary formation during development. In this study we describe the characterization of zebrafish Fat, the first non-mammalian, vertebrate Fat homologue to be identified. The Fat protein has 64% amino acid identity and 80% similarity to human FAT and an identical domain structure to other vertebrate Fat proteins. During embryogenesis fat mRNA is expressed in the developing brain, specialised epithelial surfaces the notochord, ears, eyes and digestive tract, a pattern similar but distinct to that found in mammals. (c) 2005 Elsevier B.V. All rights reserved.

Intra-abdominal pressure increases stiffness of the lumbar spine

Intra-abdominal pressure (IAP) increases during many tasks and has been argued to increase stability and stiffness of the spine. Although several studies have shown a relationship between the IAP increase and spinal stability, it has been impossible to determine whether this augmentation of mechanical support for the spine is due to the increase in IAP or the abdominal muscle activity which contributes to it. The present study determined whether spinal stiffness increased when IAP increased without concurrent activity of the abdominal and back extensor muscles. A sustained increase in IAP was evoked by tetanic stimulation of the phrenic nerves either. unilaterally or bilaterally at 20 Hz (for 5 s) via percutaneous electrodes in three subjects. Spinal stiffness was measured as the force required to displace an indentor over the L4 or L2 spinous process with the subjects lying prone. Stiffness was measured as the slope of the regression line fitted to the linear region of the force-displacement curve. Tetanic stimulation of the diaphragm increased IAP by 27-61% of a maximal voluntary pressure increase and increased the stiffness of the spine by 8-31% of resting levels. The increase in spinal stiffness was positively correlated with the size of the IAP increase. IAP increased stiffness at L2 and L4 level. The results of this:study provide evidence that the stiffness of the lumbar spine is increased when IAP is elevated. (C) 2004 Elsevier Ltd. All rights reserved.

Effect of curve fitting parameters on quantitative analysis of Fe0.94O and Fe2O3 using XPS

The XPS peaks of Fe 3p for Fe2+ and Fe3+ in FeO and Fe2O3, respectively, have been measured and the effects of curve fitting parameters on interpretation of the data have been analysed. Firstly, the peak fit parameters, i.e. (1) the number of peaks to be deconvoluted, (2) the range of the peak for back ground subtraction, (3) straight line (Li) or the Shirley (Sh) background subtraction method, (4) GL ratio (the ratio of Gaussian and Lorentzian contribution to the peak shape) and (5) asymmetry factor (AS), are manually selected. Secondly, the standard peak fit parameters were systematically investigated. The peak shape was fitted to a Voigt function by changing the peak position, the peak height and the full width at half maximum (FWHM) to minimize the chi(2). The recommended peak positions and peak parameters for Fe2+ and Fe3+ in iron oxides have been determined. (c) 2006 Elsevier B.V. All rights reserved.

Discovery of cyclotide-like protein sequences in graminaceous crop plants: Ancestral precursors of circular proteins?

Cyclotides are peptides from plants of the Rubiaceae and Violaceae families that have the unusual characteristic of a macrocylic backbone. They are further characterized by their incorporation of a cystine knot in which two disulfides, along with the intervening backbone residues, form a ring through which a third disulfide is threaded. The cyclotides have been found in every Violaceae species screened to date but are apparently present in only a few Rubiaceae species. The selective distribution reported so far raises questions about the evolution of the cyclotides within the plant kingdom. In this study, we use a combined bioinformatics and expression analysis approach to elucidate the evolution and distribution of the cyclotides in the plant kingdom and report the discovery of related sequences widespread in the Poaceae family, including crop plants such as rice ( Oryza sativa), maize ( Zea mays), and wheat ( Triticum aestivum), which carry considerable economic and social importance. The presence of cyclotide-like sequences within these plants suggests that the cyclotides may be derived from an ancestral gene of great antiquity. Quantitative RT-PCR was used to show that two of the discovered cyclotide-like genes from rice and barley ( Hordeum vulgare) have tissue-specific expression patterns.