Past, Present and Future Molecular Approaches to Improve Yield in Wheat

This chapter addresses the development and use of molecular markers for yield enhancement in wheat. Since their key goal for breeding is to maximize yield, extensive efforts have been made toward the improvement of yield. Agronomic traits related to yield, yield-related, disease resistance, and abiotic stresses are considered to be quantitative traits (QTLs), also known as complex traits, because they are controlled by numerous genes and are affected by environmental factors. Researchers have been studying such traits in the past decades for the development of molecular markers which can be used in various wheat breeding studies mainly involving restriction fragment length polymorphism (RFLP), simple sequence repeat (SSR), single nucleotide polymorphism (SNP), random amplified polymorphic DNA (RAPD), and amplified fragment length polymorphism (AFLP). Furthermore, the advent of next-generation sequencing (NGS) has accelerated the discovery of agronomically important genes. All of the technologies have enabled great advances for increasing the productivity of wheat. Here, the past history of first-generation sequencing, present status of second-generation sequencing, and future potential of translational genomics linked to the yield will be discussed

Post-tetanic increase in the fast-releasing synaptic vesicle pool at the expense of the slowly releasing pool

Post-tetanic potentiation (PTP) at the calyx of Held synapse is caused by increases not only in release probability (P(r)) but also in the readily releasable pool size estimated from a cumulative plot of excitatory post-synaptic current amplitudes (RRP(cum)), which contribute to the augmentation phase and the late phase of PTP, respectively. The vesicle pool dynamics underlying the latter has not been investigated, because PTP is abolished by presynaptic whole-cell patch clamp. We found that supplement of recombinant calmodulin to the presynaptic pipette solution rescued the increase in the RRP(cum) after high-frequency stimulation (100 Hz for 4-s duration, HFS), but not the increase in P(r). Release-competent synaptic vesicles (SVs) are heterogeneous in their releasing kinetics. To investigate post-tetanic changes of fast and slowly releasing SV pool (FRP and SRP) sizes, we estimated quantal release rates before and 40 s after HFS using the deconvolution method. After HFS, the FRP size increased by 19.1% and the SRP size decreased by 25.4%, whereas the sum of FRP and SRP sizes did not increase. Similar changes in the RRP were induced by a single long depolarizing pulse (100 ms). The post-tetanic complementary changes of FRP and SRP sizes were abolished by inhibitors of myosin II or myosin light chain kinase. The post-tetanic increase in the FRP size coupled to a decrease in the SRP size provides the first line of evidence for the idea that a slowly releasing SV can be converted to a fast releasing one.Jordan R, 2005, BIOPHYS J, V89, P2091, DOI 10.1529/biophysj.105.061663Kim MH, 2005, J NEUROSCI, V25, P6057, DOI 10.1523/JNEUROSCI.0454-05.2005Korogod N, 2005, J NEUROSCI, V25, P5127, DOI 10.1523/JNEUROSCI.1295-05.2005Moulder KL, 2005, J NEUROSCI, V25, P3842, DOI 10.1523/JINEUROSC.5231-04.2005Habets RLP, 2005, J PHYSIOL-LONDON, V564, P173, DOI 10.1113/jphysiol.2004.079160Felmy F, 2003, NEURON, V37, P801Satzler K, 2002, J NEUROSCI, V22, P10567Wadel K, 2007, NEURON, V53, P563, DOI 10.1016/j.neuron.2007.01.021Wolfel M, 2007, J NEUROSCI, V27, P3198, DOI 10.1523/JNEUROSCI.4471-06.2007Habets RLP, 2007, J PHYSIOL-LONDON, V581, P467, DOI 10.1113/jphysiol.2006.127365Korogod N, 2007, P NATL ACAD SCI USA, V104, P15923, DOI 10.1073/pnas.0704603104Hosoi N, 2007, J NEUROSCI, V27, P14286, DOI 10.1523/JNEUROSCI.4122-07.2007Zikich D, 2008, J NEUROSCI, V28, P1949, DOI 10.1523/JNEUROSCI.5096-07.2008Mongillo G, 2008, SCIENCE, V319, P1543, DOI 10.1126/science.1150769Srinivasan G, 2008, J NEUROPHYSIOL, V99, P1810, DOI 10.1152/jn.00949.2007Lee JS, 2008, J NEUROSCI, V28, P7945, DOI 10.1523/JNEUROSCI.2165-08.2008Awatramani GB, 2005, NEURON, V48, P109, DOI 10.1016/j.neuron.2005.08.038Kushmerick C, 2006, J NEUROSCI, V26, P1366, DOI 10.1523/JNEUROSCI.3889-05.2006Sakaba T, 2006, J NEUROSCI, V26, P5863, DOI 10.1523/JNEUROSCI.0182-06.2006Tokuoka H, 2006, J NEUROSCI, V26, P11606, DOI 10.1523/JNEUROSCI.3400-06.2006Habets RLP, 2006, J NEUROPHYSIOL, V96, P2868, DOI 10.1152/jn.00427.2006Lou XL, 2008, J NEUROSCI, V28, P8257, DOI 10.1523/JNEUROSCI.0550-08.2008Neher E, 2008, NEURON, V59, P861, DOI 10.1016/j.neuron.2008.08.019He LM, 2009, NATURE, V459, P93, DOI 10.1038/nature07860Schneggenburger R, 2002, TRENDS NEUROSCI, V25, P206Tsujimoto T, 2002, SCIENCE, V295, P2276, DOI 10.1126/science.1068278Meinrenken CJ, 2002, J NEUROSCI, V22, P1648Sakaba T, 2001, NEURON, V32, P1119Neher E, 2001, J NEUROSCI, V21, P444Sakaba T, 2001, P NATL ACAD SCI USA, V98, P331Dinkelacker V, 2000, J NEUROSCI, V20, P8377Wu LG, 1999, NEURON, V23, P821Peersen OB, 1997, PROTEIN SCI, V6, P794Borst JGG, 1996, NATURE, V383, P431PUSCH M, 1988, PFLUG ARCH EUR J PHY, V411, P204

Role of G{alpha}12 and G{alpha}13 as Novel Switches for the Activity of Nrf2, a Key Antioxidative Transcription Factor

G{alpha}12 and G{alpha}13 function as molecular regulators responding to extracellular stimuli. NF-E2-related factor 2 (Nrf2) is involved in a protective adaptive response to oxidative stress. This study investigated the regulation of Nrf2 by G{alpha}12 and G{alpha}13. A deficiency of G{alpha}12, but not of G{alpha}13, enhanced Nrf2 activity and target gene transactivation in embryo fibroblasts. In mice, G{alpha}12 knockout activated Nrf2 and thereby facilitated heme catabolism to bilirubin and its glucuronosyl conjugations. An oligonucleotide microarray demonstrated the transactivation of Nrf2 target genes by G{alpha}12 gene knockout. G{alpha}12 deficiency reduced Jun N-terminal protein kinase (JNK)-dependent Nrf2 ubiquitination required for proteasomal degradation, and so did G{alpha}13 deficiency. The absence of G{alpha}12, but not of G{alpha}13, increased protein kinase C {delta} (PKC {delta}) activation and the PKC {delta}-mediated serine phosphorylation of Nrf2. G{alpha}13 gene knockout or knockdown abrogated the Nrf2 phosphorylation induced by G{alpha}12 deficiency, suggesting that relief from G{alpha}12 repression leads to the G{alpha}13-mediated activation of Nrf2. Constitutive activation of G{alpha}13 promoted Nrf2 activity and target gene induction via Rho-mediated PKC {delta} activation, corroborating positive regulation by G{alpha}13. In summary, G{alpha}12 and G{alpha}13 transmit a JNK-dependent signal for Nrf2 ubiquitination, whereas G{alpha}13 regulates Rho-PKC {delta}-mediated Nrf2 phosphorylation, which is negatively balanced by G{alpha}12

Synergistic Effects of Hyaluronate - Epidermal Growth Factor Conjugate Patch on Chronic Wound Healing

The proteolytic microenvironment in the wound area reduces the stability and the half-life of growth factors in vivo, making difficult the topical delivery of growth factors. Here, epidermal growth factor (EGF) was conjugated to hyaluronate (HA) to improve the long-term stability against enzymatic degradation and the therapeutic effect by enhancing the biological interaction with HA receptors on skin cells. After the synthesis of HA-EGF conjugates, they were incorporated into a patch-type formulation for the facile topical application and sustained release of EGF. According to ELISA, the HA-EGF conjugates showed a long-term stability compared with native EGF. Furthermore, HA-EGF conjugates appeared to interact with skin cells through two types of HA and EGF receptors, resulting in a synergistically improved healing effect. Taken together, we could confirm the feasibility of HA-EGF conjugates for the transdermal treatment of chronic wounds.11Ysciescopu

Indium as an efficient ohmic contact to N-face n-GaN of GaN-based vertical light-emitting diodes

We propose indium (In), a low work function and nitride-forming element, as an efficient ohmic contact layer to N-face n-GaN. While conventional Al-based ohmic contacts show severe degradation after annealing at 300 C, In-based ohmic contacts display considerable improvement in contact resistivity. The annealing-induced enhancement of ohmic behavior in In-based contacts is attributed to the formation of an InN interfacial layer, which is supported by x-ray photoemission spectroscopy measurements. These results suggest that In is of particular importance for application as reliable ohmic contacts to n-GaN of GaN-based vertical light-emitting diodes.open3

Pharmacokinetics of a telmisartan, amlodipine and hydrochlorothiazide fixed-dose combination: A replicate crossover study in healthy Korean male subjects

Purpose: To compare the tolerability and pharmacokinetic profiles of telmisartan, amlodipine, and hydrochlorothiazide (HCTZ) in a fixed-dose combination (FDC, test product) with a co-administered telmisartan/amlodipine FDC and HCTZ in a single-entity tablet (reference product)Methods: This was a single-dose, randomized, open-label, replicate crossover study conducted in healthy male Korean volunteers aged 19 – 50 years. Fasting randomized subjects received a newly developed test product (telmisartan/ amlodipine/HCTZ, 80/10/25 mg) or two tablets of Twynsta® (40/5 mg) and one tablet of HCTZ (25 mg) as reference products. After a washout period, each group replicated the exposure of the other group.Results: The AUClast (h•ng/mL) geometric mean was 3,194.87 and 3,273.77 for the telmisartan test and reference products, respectively; 329.92 and 315.13 for the amlodipine test and reference products; 1,203.98 and 1,150.86 for the HCTZ test and reference products, respectively. The geometric mean of Cmax (ng/mL) was 543.04 and 497.81 for the telmisartan test and reference products, respectively; 7.74 and 7.34 for the amlodipine test and reference products; 218.71 and 184.39 for the HCTZ test and reference products, respectively. For telmisartan, the 90 % CI of GMRs of AUClast (h•ng/mL) and Cmax (ng/mL) were 0.9414 – 1.0496 and 1.0246 – 1.2792, respectively; the coefficient of variation (CV) of telmisartan Cmax was 41.96 %.Conclusion: A formulated FDC tablet containing a telmisartan/amlodipine/HCTZ combination (80/10/25mg) was bioequivalent to a co-administrated commercially available telmisartan/amlodipine combination and HCTZ tablets at equivalent concentrations.Keywords: Fixed-dose combination, Hypertension, Telmisartan, Amlodipine besylate, Hydrochlorothiazide, Pharmacokinetic

Presynaptic release probability and readily releasable pool size are regulated by two independent mechanisms during posttetanic potentiation at the calyx of Held synapse

At the immature calyx of Held, the fast decay phase of a Ca(2+) transient induced by tetanic stimulation (TS) was followed by a period of elevated [Ca(2+)](i) for tens of seconds, referred to as posttetanic residual calcium (Ca(res)). We investigated the source of Ca(res) and its contribution to posttetanic potentiation (PTP). After TS (100 Hz for 4 s), posttetanic Ca(res) at the calyx of Held was largely abolished by tetraphenylphosphonium (TPP(+)) or Ru360, which inhibit mitochondrial Na(+)-dependent Ca(2+) efflux and Ca(2+) uniporter, respectively. Whereas the control PTP lasted longer than Ca(res), inhibition of Ca(res) by TPP(+) resulted in preferential suppression of the early phase of PTP, the decay time course of which well matched with that of Ca(res). TS induced significant increases in release probability (P(r)) and the size of the readily releasable pool (RRP), which were estimated from plots of cumulative EPSC amplitudes. TPP(+) or Ru360 suppressed the posttetanic increase in P(r), whereas it had little effect on the increase in RRP size. Moreover, the posttetanic increase in P(r), but not in RRP size, showed a linear correlation with the amount of Ca(res). In contrast, myosin light chain kinase (MLCK) inhibitors and blebbistatin reduced the posttetanic increase in RRP size with no effect on the increase in P(r). Application of TPP(+) in the presence of MLCK inhibitor peptide caused further suppression of PTP. These findings suggest that Ca(res) released from mitochondria and activation of MLCK are primarily responsible for the increase in P(r) and that in the RRP size, respectively

Cyclic ADP Ribose-Dependent Ca2+ Release by Group I Metabotropic Glutamate Receptors in Acutely Dissociated Rat Hippocampal Neurons

Group I metabotropic glutamate receptors (group I mGluRs; mGluR1 and mGluR5) exert diverse effects on neuronal and synaptic functions, many of which are regulated by intracellular Ca2+. In this study, we characterized the cellular mechanisms underlying Ca2+ mobilization induced by (RS)-3,5-dihydroxyphenylglycine (DHPG; a specific group I mGluR agonist) in the somata of acutely dissociated rat hippocampal neurons using microfluorometry. We found that DHPG activates mGluR5 to mobilize intracellular Ca2+ from ryanodine-sensitive stores via cyclic adenosine diphosphate ribose (cADPR), while the PLC/IP3 signaling pathway was not involved in Ca2+ mobilization. The application of glutamate, which depolarized the membrane potential by 28.5±4.9 mV (n = 4), led to transient Ca2+ mobilization by mGluR5 and Ca2+ influx through L-type Ca2+ channels. We found no evidence that mGluR5-mediated Ca2+ release and Ca2+ influx through L-type Ca2+ channels interact to generate supralinear Ca2+ transients. Our study provides novel insights into the mechanisms of intracellular Ca2+ mobilization by mGluR5 in the somata of hippocampal neurons