Potential of proteins and their expression level in marine phytoplankton (Prymnesium parvum) as biomarker of N, P and Fe conditions in aquatic systems

Nitrogen (N), phosphorus (P) and Iron (Fe) are im-portant nutrients for phytoplankton, and are key limiting nutrients in many marine systems. In the present study, growth and protein expression of ma-rine phytoplankton Prymnesium parvum under dif-ferent nitrate, phosphate and iron conditions were investigated in order to evaluate whether proteins and their expression level can be used as biomarker of N, P, and Fe conditions in aquatic systems. The growth of P. parvum increased with the increase of nitrate, phosphate and iron concentrations in the culture medium. Protein expression levels also differed significantly (p < 0.001) for different nitrate, phosphate and iron conditions in the culture medium. The expression level of an 83 kDa protein at 0 and 5 µM nitrate treatments differed significantly (p < 0.001) from those at 20, 30, 50 and 100 µM nitrate treatments, indicating the expression levels of this protein as a biomarker of N status in the culture me-dium. A 121 kDa protein was up-regulated at phos-phate stress conditions ([P] = 1.0 µM), while this pro-tein was not expressed at phosphate replete conditions ([P] = 5 µM). Therefore, the expression of 121 kDa protein in P. parvum is indicative of phosphate replete condition in aquatic systems. The expression level of a 42 kDa was significantly higher (p < 0.01) at Fe-stress condition ([Fe] = 0.01 µM) than Fe-replete conditions ([Fe] = 0.1 µM). In addition, a new protein of 103 kDa was only expressed under Fe-deplete condition ([Fe] = 0.01 µM). Therefore, the 42 and 103 kDa proteins can be used as a biomarker of Fe-limitation condition of aquatic systems. However, further studies (two dimensional gel electrophoresis and mass spectrometry) are needed to identify and characterize these proteins in P. parvum

Effect of Light-Emitting Diode (Led) Light on the Gene Expression Related With Ascorbate Biosynthesis and Metabolism in Broccoli Florets

Ascorbate is one of the most abundant soluble antioxidants in the plant. Multiple functions of ascorbate in photo protection have been proposed, including scavenging of reactive oxygen species generated by oxygen photoreduction and photorespiration. There is still unclear information relation to LED light with Ascorbate biosynthesis and metabolism, yellowing, chlorophyll content, and ethylene production in broccoli florets. The effect of light-emitting diodes (LED) light on ascorbate (AsA) biosynthesis and metabolism in broccoli (Brassica oleracea L. var. Italica) cultivar “Ryokurei” were studied using red (660 nm), blue (470 nm) and white LED lights as the light source and also no light treatment as the control. Gene expression involved in the biosynthesis and metabolism of AsA, AsA content, color, chlorophyll content and ethylene production rate on the postharvest broccoli were observed in 4 days. The result showed that after two days, red light treatment significantly (p &lt; 0,05) delayed the decrease of ascorbate content. The result was supported by observations using Real-Time Quantitative RT-PCR showed that red light treatment can suppress mRNA level of BO-APX1, BO-APX2, and BO-sAPX on the third day. Observation of BO-GLDH mRNA level was increased in the third-day exposure of red LED light. Therefore red LED light showed up-regulated AsA biosynthesis transcriptional level. Enzymes which possibility responsible for AsA metabolism and biosynthesis in a row were Ascorbate Peroxide (APX) and L-Galactono-1,4-Lactone Dehydrogenase (GLDH). The regulation of this gene expression might contribute to the suppression of AsA reduction by red LED light treatment in broccoli. Red LED also showed suppression of yellowing and decline the chlorophyll content in postharvest broccoli florets. Keywords: ascorbate, LED; broccoli; gene expression; real-time quantitative RT-PCR

Planar microwave devices fabricated by ion-implantation patterning of high-temperature superconductors

We have applied ion-implantation inhibit patterning as a new method of fabricating low-loss microwave transmission lines in high-temperature superconductor thin films. To determine the effectiveness of this technique, we fabricated coplanar waveguide transmission lines in YBa2Cu3O7 – thin films that had been deposited on LaAlO3 substrates using pulsed laser deposition. Microwave characterizations of these lines are compared to a reference line fabricated with conventional ion milling. At 76 K and 12 GHz, the attenuation constants of the ion-implanted transmission lines are approximated 0.02 dB/mm, and the overall loss response is indistinguishable from that of the ion-milled device.published_or_final_versio

Recovery of the persistent current induced by the electron-electron interaction in mesoscopic metallic rings

Persistent currents in mesoscopic metallic rings induced by static magnetic fields are investigated by means of a Hamiltonian which incorporates diagonal disorder and the electron-electron interaction through a Hubbard term ($U$). Correlations are included up to second order perturbation theory which is shown to work accurately for $U$ of the order of the hopping integral. If disorder is not very strong, interactions increase the current up to near its value for a clean metal. Averaging over ring lengths eliminates the first Fourier component of the current and reduces its value, which remains low after interactions are included.Comment: uuencoded gzipped tar file containing the manuscript (tex file) and four figures (postscript files). Accepted for publication in Solid State Communications. Send e-mail to: [email protected]

Random Bond Effect in the Quantum Spin System (Tl1−x_{1-x}Kx_{x})CuCl3_3

The effect of exchange bond randomness on the ground state and the field-induced magnetic ordering was investigated through magnetization measurements in the spin-1/2 mixed quantum spin system (Tl$_{1-x}$K$_{x}$)CuCl$_3$ for $x<0.36$. Both parent compounds TlCuCl$_3$ and KCuCl$_3$ are coupled spin dimer systems, which have the singlet ground state with excitation gaps ${\Delta}/k_{\rm B}=7.7$ K and 31 K, respectively. Due to bond randomness, the singlet ground state turns into the magnetic state with finite susceptibility, nevertheless, the excitation gap remains. Field-induced magnetic ordering, which can be described by the Bose condensation of excited triplets, magnons, was observed as in the parent systems. The phase transition temperature is suppressed by the bond randomness. This behavior may be attributed to the localization effect.Comment: 19 pages, 7 figures, 12 eps files, revtex, will appear in PR

Evaluation of intra- and interspecific divergence of satellite DNA sequences by nucleotide frequency calculation and pairwise sequence comparison

Satellite DNA sequences are known to be highly variable and to have been subjected to concerted evolution that homogenizes member sequences within species. We have analyzed the mode of evolution of satellite DNA sequences in four fishes from the genus Diplodus by calculating the nucleotide frequency of the sequence array and the phylogenetic distances between member sequences. Calculation of nucleotide frequency and pairwise sequence comparison enabled us to characterize the divergence among member sequences in this satellite DNA family. The results suggest that the evolutionary rate of satellite DNA in D. bellottii is about two-fold greater than the average of the other three fishes, and that the sequence homogenization event occurred in D. puntazzo more recently than in the others. The procedures described here are effective to characterize mode of evolution of satellite DNA

Structural Mechanism for the Specific Assembly and Activation of the Extracellular Signal Regulated Kinase 5 (ERK5) Module

Mitogen-activated protein kinase (MAPK) activation depends on a linear binding motif found in all MAPK kinases (MKK). In addition, the PB1 (Phox and Bem1) domain of MKK5 is required for extracellular signal regulated kinase 5 (ERK5) activation. We present the crystal structure of ERK5 in complex with an MKK5 construct comprised of the PB1 domain and the linear binding motif. We show that ERK5 has distinct protein-protein interaction surfaces compared with ERK2, which is the closest ERK5 paralog. The two MAPKs have characteristically different physiological functions and their distinct protein-protein interaction surface topography enables them to bind different sets of activators and substrates. Structural and biochemical characterization revealed that the MKK5 PB1 domain cooperates with the MAPK binding linear motif to achieve substrate specific binding, and it also enables co-recruitment of the upstream activating enzyme and the downstream substrate into one signaling competent complex. Studies on present day MAPKs and MKKs hint on the way protein kinase networks may evolve. In particular, they suggest how paralogous enzymes with similar catalytic properties could acquire novel signaling roles by merely changing the way they make physical links to other proteins

Identifying dynamical modules from genetic regulatory systems: applications to the segment polarity network

BACKGROUND It is widely accepted that genetic regulatory systems are 'modular', in that the whole system is made up of smaller 'subsystems' corresponding to specific biological functions. Most attempts to identify modules in genetic regulatory systems have relied on the topology of the underlying network. However, it is the temporal activity (dynamics) of genes and proteins that corresponds to biological functions, and hence it is dynamics that we focus on here for identifying subsystems. RESULTS Using Boolean network models as an exemplar, we present a new technique to identify subsystems, based on their dynamical properties. The main part of the method depends only on the stable dynamics (attractors) of the system, thus requiring no prior knowledge of the underlying network. However, knowledge of the logical relationships between the network components can be used to describe how each subsystem is regulated. To demonstrate its applicability to genetic regulatory systems, we apply the method to a model of the Drosophila segment polarity network, providing a detailed breakdown of the system. CONCLUSION We have designed a technique for decomposing any set of discrete-state, discrete-time attractors into subsystems. Having a suitable mathematical model also allows us to describe how each subsystem is regulated and how robust each subsystem is against perturbations. However, since the subsystems are found directly from the attractors, a mathematical model or underlying network topology is not necessarily required to identify them, potentially allowing the method to be applied directly to experimental expression data