NADP-malate dehydrogenase gene evolution in Andropogoneae (Poaceae): gene duplication followed by sub-functionalization

• Background and Aims Plastid NADP-dependent malate dehydrogenase (MDH) catalyses the conversion of oxaloacetate to malate. In C(4) plants, it is involved in photosynthetic carbon assimilation. In Poaceae, one NADP-MDH gene has been identified in rice (C(3); Erhartoideae) and maize (C(4); Panicoideae), whereas two tandemly repeated genes have been identified in Sorghum (C(4); Panicoideae). In the present study, the molecular evolution of the NADP-MDH multigene family was investigated in order to analyse how the C(4) isoform has evolved over a broader range of panicoid grasses. • Methods Polymerase chain reaction (PCR)-based cloning was used to isolate cDNAs encoding NADP-MDHs from 15 species of Panicoideae. A gene phylogeny was reconstructed based on cDNA sequences using distance and maximum parsimony methods. Episodic selection along some branches of the phylogenetic tree was tested by analysing non-synonymous and synonymous rate ratios.Transcription of NADP-MDH genes was compared in green leaves of five accessions of Saccharum, Sorghum and Vetiveria using a semi-quantitative PCR approach. • Key Results Phylogenetic analyses of these data support the existence of two NADP-MDH gene lineages (NMDH-I and NMDH-II) in several Andropogoneae (i.e. Saccharum, Sorghum and Vetiveria). Episodic positive selection was shown along the basal branch of the NMDH-II clade. Three amino acid modifications allow the two gene lineages to be distinguished, suggesting a positive selection at these sites. In green leaves, we showed that the transcript accumulation was higher for NMDH-I than for NMDH-II. • Conclusions It is hypothesized that the maintenance of both NADP-MDH genes in some Andropogoneae is due to a partition of the original functions across both copies. NMDH-I probably corresponds to the C(4) isoform as previously suggested. Nevertheless, some C(4) species (e.g. maize) only have one gene which should be selected for its high expression level in leaves. This study confirms that gene duplicates have been recruited for C(4) photosynthesis but are not required in every case

NADP-Malate Dehydrogenase Gene Evolution in Andropogoneae (Poaceae): Gene Duplication Followed by Sub-functionalization

• Background and Aims Plastid NADP-dependent malate dehydrogenase (MDH) catalyses the conversion of oxaloacetate to malate. In C4 plants, it is involved in photosynthetic carbon assimilation. In Poaceae, one NADP-MDH gene has been identified in rice (C3; Erhartoideae) and maize (C4; Panicoideae), whereas two tandemly repeated genes have been identified in Sorghum (C4; Panicoideae). In the present study, the molecular evolution of the NADP-MDH multigene family was investigated in order to analyse how the C4 isoform has evolved over a broader range of panicoid grasses. • Methods Polymerase chain reaction (PCR)-based cloning was used to isolate cDNAs encoding NADP-MDHs from 15 species of Panicoideae. A gene phylogeny was reconstructed based on cDNA sequences using distance and maximum parsimony methods. Episodic selection along some branches of the phylogenetic tree was tested by analysing non-synonymous and synonymous rate ratios.Transcription of NADP-MDH genes was compared in green leaves of five accessions of Saccharum, Sorghum and Vetiveria using a semi-quantitative PCR approach. • Key Results Phylogenetic analyses of these data support the existence of two NADP-MDH gene lineages (NMDH-I and NMDH-II) in several Andropogoneae (i.e. Saccharum, Sorghum and Vetiveria). Episodic positive selection was shown along the basal branch of the NMDH-II clade. Three amino acid modifications allow the two gene lineages to be distinguished, suggesting a positive selection at these sites. In green leaves, we showed that the transcript accumulation was higher for NMDH-I than for NMDH-II. • Conclusions It is hypothesized that the maintenance of both NADP-MDH genes in some Andropogoneae is due to a partition of the original functions across both copies. NMDH-I probably corresponds to the C4 isoform as previously suggested. Nevertheless, some C4 species (e.g. maize) only have one gene which should be selected for its high expression level in leaves. This study confirms that gene duplicates have been recruited for C4 photosynthesis but are not required in every cas

Optimizing the Optoelectronic Properties of Conjugated Polymers Through Metal-Ligand Coordination

From the phones at our fingertips to the solar panels on our roofs, humans are becoming increasingly dependent on electronics for information, entertainment, and to power their daily lives. Further advancements are paving the way for a new age of high-performance, flexible devices. Organic electronics made from conjugated semiconducting polymers are showing great potential as a softer and more processable material than brittle silicon used in today’s devices, while exhibiting comparable charge transport to silicon. However, one key challenge with these organic polymers is the difficulty to control their optical properties and charge transport in devices. Electronics must interact with and alter their lighting while efficiently conducting electricity. Therefore, the desired material must be tuneable to precisely control these important properties. In this research, a novel organic diketopyrrolopyrrole-based conjugated polymer is presented as a leading candidate for optoelectronics. This polymer uses noncovalent metal-ligand interactions, enabled by using specific terpyridine ligands, to fine-tune its ability to emit light and transport electrons. Various transition metal ions, including Fe2+, Co2+, Zn2+, and Mn2+, were introduced into the polymer to determine which species would coordinate most efficiently with the ligand, altering its optical nature. Results from fluorescence and absorption spectroscopies showed that the manganese ion coordinated the weakest to the ligand, while iron and cobalt ions bound the most efficiently and optimally altered emission intensity. Thus, iron and cobalt were identified as great candidates for metal-ligand coordination within the polymer for optimal optoelectronic capabilities. These findings contribute to the continued pursuit of creating efficient organic optoelectronics through the promising technique of metal-ligand interactions. Keywords: organic electronics, conjugated polymer, optoelectronics, metal-ligand interaction

The BRST-invariant vacuum state of the Gribov-Zwanziger theory

We revisit the effective action of the Gribov-Zwanziger theory, taking into due account the BRST symmetry and renormalization (group invariance) of the construction. We compute at one loop the effective potential, showing the emergence of BRST-invariant dimension 2 condensates stabilizing the vacuum. This paper sets the stage at zero temperature, and clears the way to studying the Gribov-Zwanziger gap equations, and particularly the horizon condition, at finite temperature in future work.Comment: 18 pages, 4 .pdf figure

Deciphering metal-induced oxidative damages on glycated albumin structure and function

Background: Metal ions such as copper or zinc are involved in the development of neurodegenerative pathologies and metabolic diseases such as diabetes mellitus. Albumin structure and functions are impaired following metal- and glucose-mediated oxidative alterations. The aim of this study was to elucidate effects of Cu(II) and Zn(II) ions on glucose-induced modifications in albumin by focusing on glycation, aggregation, oxidation and functional aspects. Methods: Aggregation and conformational changes in albumin were monitored by spectroscopy, fluorescence and microscopy techniques. Biochemical assays such as carbonyl, thiol groups, albumin-bound Cu, fructosamine and amine group measurements were used. Cellular assays were used to gain functional information concerning antioxidant activity of oxidized albumins. Results: Both metals promoted inhibition of albumin glycation associated with an enhanced aggregation and oxidation process. Metal ions gave rise to the formation of β-amyloid type aggregates in albumin exhibiting impaired antioxidant properties and toxic activity to murine microglia cells (BV2). The differential efficiency of both metal ions to inhibit albumin glycation, to promote aggregation and to affect cellular physiology is compared. Conclusions and general significance: Considering the key role of oxidized protein in pathology complications, glycation-mediated and metal ion-induced impairment of albumin properties might be important parameters to be followed and fought. © 2013 Elsevier B.V

New proaporphines from the bark of Phoebe scortechinii

The phytochemical study of the bark of Malaysian Phoebe scortechinii (Lauraceae) has resulted in the isolation and identification of two new proaporphine alkaloids; (+)-scortechiniine A (1) and (+)-scortechiniine B (2) together with two known proaporphines; (−)-hexahydromecambrine A (3), (−)-norhexahydromecambrine A (4), and one aporphine; norboldine (5). Structural elucidations of these alkaloids were performed using spectroscopic methods especially 1D and 2D 1H and 13C NMR

Subsurface damage measurement of ground fused silica parts by HF etching techniques

International audienceDetection and measurement of subsurface damage of ground optical surfaces are of major concern in the assessment of high damage thresholds fused silica optics for high power laser applications. We herein detail a new principle of SSD measurement based on the utilization of HF acid etching. We also review and compare different subsurface damage (SSD) characterization techniques applied to ground and fine ground fused silica samples. We demonstrate good concordance between the different measurements

Forming low-cost, high quality carbon tows for automotive application.

Carbon fiber reinforced composites are widely used in many industries due to their high performance. Its application in the aerospace industry has increased significantly, however, in mass produced automobile sector it is still limited. The current production of carbon fiber tow is slow and capital intensive. Thus, carbon manufactures produce higher tow counts to increase production rate to reduce its cost. In order to offset the higher cost of carbon fiber composite, an innovative and unique approach has been developed. The higher tow count carbon spools are split into smaller tow counts. Due to the delicate nature of carbon fiber, it is important to control the filamentation during that process. Different splitting process line strategies have been developed in this research work for understanding the process limitations and challenges involved. The process was made feasible for production by developing a fully automated process line with a laser feedback system. The system splits a 12K spool into two 6K tows. The quality of the 6K split tows has been determined statistically by recording real time data from the laser during the splitting process. It was demonstrated that the proposed process effectively controls filamentation and produces consistent tow quality.Company research funding by Bentley Motors Limite

Phase diagram of insulating crystal and quantum Hall states in ABC-stacked trilayer graphene

In the presence of a perpendicular magnetic field, ABC-stacked trilayer graphene's chiral band structure supports a 12-fold degenerate N=0 Landau level (LL). Along with the valley and spin degrees of freedom, the zeroth LL contains additional quantum numbers associated with the LL orbital index $$. Remote inter-layer hopping terms and external potential difference $\Delta_{B}$ between the layers lead to LL splitting by introducing a gap $$ between the degenerate zero-energy triplet LL orbitals. Assuming that the spin and valley degrees of freedom are frozen, we study the phase diagram of this system resulting from competition of the single particle LL splitting and Coulomb interactions within the Hartree-Fock approximation at integer filling factors. Above a critical value $\Delta_{LL}^{c}$ of the external potential difference i,e, for $|\Delta_{LL}| >\Delta_{LL}^{c}$, the ground state is a uniform quantum Hall state where the electrons occupy the lowest unoccupied LL orbital index. For $|\Delta_{LL}| <\Delta_{LL}^{c}$ (which corresponds to large positive or negative values of $\Delta_{B}$) the uniform QH state is unstable to the formation of a crystal state at integer filling factors. This phase transition should be characterized by a Hall plateau transition as a function of $\Delta_{LL}$ at a fixed filling factor. We also study the properties of this crystal state and discuss its experimental detection.Comment: 16 pages with 13 figure

Separate and combined analysis of successive dependent outcomes after breast-conservation surgery: recurrence, metastases, second cancer and death

<p>Abstract</p> <p>Background</p> <p>In the setting of recurrent events, research studies commonly count only the first occurrence of an outcome in a subject. However this approach does not correctly reflect the natural history of the disease. The objective is to jointly identify prognostic factors associated with locoregional recurrences (LRR), contralateral breast cancer, distant metastases (DM), other primary cancer than breast and breast cancer death and to evaluate the correlation between these events.</p> <p>Methods</p> <p>Patients (n = 919) with a primary invasive breast cancer and treated in a cancer center in South-Western France with breast-conserving surgery from 1990 to 1994 and followed up to January 2006 were included. Several types of non-independent events could be observed for the same patient: a LRR, a contralateral breast cancer, DM, other primary cancer than breast and breast cancer death. Data were analyzed separately and together using a random-effects survival model.</p> <p>Results</p> <p>LRR represent the most frequent type of first failure (14.6%). The risk of any event is higher for young women (less than 40 years old) and in the first 10 years of follow-up after the surgery. In the combined analysis histological tumor size, grade, number of positive nodes, progesterone receptor status and treatment combination are prognostic factors of any event. The results show a significant dependence between these events with a successively increasing risk of a new event after the first and second event. The risk of developing a new failure is greatly increased (RR = 4.25; 95%CI: 2.51-7.21) after developing a LRR, but also after developing DM (RR = 3.94; 95%CI: 2.23-6.96) as compared to patients who did not develop a first event.</p> <p>Conclusion</p> <p>We illustrated that the random effects survival model is a more satisfactory method to evaluate the natural history of a disease with multiple type of events.</p