Current assessment of the Red Rectangle band problem

In this paper we discuss our insights into several key problems in the identification of the Red Rectangle Bands (RRBs). We have combined three independent sets of observations in order to try to define the constraints guiding the bands. We provide a summary of the general behavior of the bands and review the evidence for a molecular origin of the bands. The extent, composition, and possible absorption effects of the bands are discussed. Comparison spectra of the strongest band obtained at three different spectral resolutions suggests that an intrinsic line width of individual rotational lines can be deduced. Spectroscopic models of several relatively simple molecules were examined in order to investigate where the current data are weak. Suggestions are made for future studies to enhance our understanding of these enigmatic bands

Insights into the ceria-catalyzed ketonization reaction for biofuels applications

The ketonization of small organic acids is a valuable reaction for biorenewable applications. Ceria has long been used as a catalyst for this reaction; however, under both liquid and vapor phase conditions, it was found that given the right temperature regime of about 150-300 °C, cerium oxide, which was previously believed to be a stable catalyst for ketonization, can undergo bulk transformations. This result, along with other literature reports, suggest that the long held belief of two separate reaction pathways for either bulk or surface ketonization reactions are not required to explain the interaction of cerium oxide with organic acids. X-ray photon spectroscopy, scanning electron microscopy, and temperature programmed decomposition results supported the formation of metal acetates and explained the occurrence of cerium reduction as well as the formation of cerium oxide/acetate whiskers. After thermogravimetry/mass spectrometry and FT-IR experiments, a single reaction sequence is proposed that can be applied to either surface or bulk reactions with ceria

Russia’s Legal Transitions: Marxist Theory, Neoclassical Economics and the Rule of Law

We review the role of economic theory in shaping the process of legal change in Russia during the two transitions it experienced during the course of the twentieth century: the transition to a socialist economy organised along the lines of state ownership of the means of production in the 1920s, and the transition to a market economy which occurred after the fall of the Soviet Union in the 1990s. Despite differences in methodology and in policy implications, Marxist theory, dominant in the 1920s, and neoclassical economics, dominant in the 1990s, offered a similarly reductive account of law as subservient to wider economic forces. In both cases, the subordinate place accorded to law undermined the transition process. Although path dependence and history are frequently invoked to explain the limited development of the rule of law in Russia during the 1990s, policy choices driven by a deterministic conception of law and economics also played a role.This is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.1007/s40803-015-0012-

The Chlorophyll Catabolite, Pheophorbide a, Confers Predation Resistance in a Larval Tortoise Beetle Shield Defense

Larval insect herbivores feeding externally on leaves are vulnerable to numerous and varied enemies. Larvae of the Neotropical herbivore, Chelymorpha alternans (Chrysomelidae:Cassidinae), possess shields made of cast skins and feces, which can be aimed and waved at attacking enemies. Prior work with C. alternans feeding on Merremia umbellata (Convolvulaceae) showed that shields offered protection from generalist predators, and polar compounds were implicated. This study used a ubiquitous ant predator, Azteca lacrymosa, in field bioassays to determine the chemical constitution of the defense. We confirmed that intact shields do protect larvae and that methanol-water leaching significantly reduced shield effectiveness. Liquid chromatography-mass spectrometry (LC-MS) of the methanolic shield extract revealed two peaks at 20.18 min and 21.97 min, both with a molecular ion at m/z 593.4, and a strong UV absorption around 409 nm, suggesting a porphyrin-type compound. LC-MS analysis of a commercial standard confirmed pheophorbide a (Pha) identity. C. alternans shields contained more than 100 μg Pha per shield. Shields leached with methanol-water did not deter ants. Methanol-water-leached shields enhanced with 3 μg of Pha were more deterrent than larvae with solvent-leached shields, while those with 5 μg additional Pha provided slightly less deterrence than larvae with intact shields. Solvent-leached shields with 10 μg added Pha were comparable to intact shields, even though the Pha concentration was less than 10% of its natural concentration. Our findings are the first to assign an ecological role for a chlorophyll catabolite as a deterrent in an insect defense

Sorting Signals, N-Terminal Modifications and Abundance of the Chloroplast Proteome

Characterization of the chloroplast proteome is needed to understand the essential contribution of the chloroplast to plant growth and development. Here we present a large scale analysis by nanoLC-Q-TOF and nanoLC-LTQ-Orbitrap mass spectrometry (MS) of ten independent chloroplast preparations from Arabidopsis thaliana which unambiguously identified 1325 proteins. Novel proteins include various kinases and putative nucleotide binding proteins. Based on repeated and independent MS based protein identifications requiring multiple matched peptide sequences, as well as literature, 916 nuclear-encoded proteins were assigned with high confidence to the plastid, of which 86% had a predicted chloroplast transit peptide (cTP). The protein abundance of soluble stromal proteins was calculated from normalized spectral counts from LTQ-Obitrap analysis and was found to cover four orders of magnitude. Comparison to gel-based quantification demonstrates that ‘spectral counting’ can provide large scale protein quantification for Arabidopsis. This quantitative information was used to determine possible biases for protein targeting prediction by TargetP and also to understand the significance of protein contaminants. The abundance data for 550 stromal proteins was used to understand abundance of metabolic pathways and chloroplast processes. We highlight the abundance of 48 stromal proteins involved in post-translational proteome homeostasis (including aminopeptidases, proteases, deformylases, chaperones, protein sorting components) and discuss the biological implications. N-terminal modifications were identified for a subset of nuclear- and chloroplast-encoded proteins and a novel N-terminal acetylation motif was discovered. Analysis of cTPs and their cleavage sites of Arabidopsis chloroplast proteins, as well as their predicted rice homologues, identified new species-dependent features, which will facilitate improved subcellular localization prediction. No evidence was found for suggested targeting via the secretory system. This study provides the most comprehensive chloroplast proteome analysis to date and an expanded Plant Proteome Database (PPDB) in which all MS data are projected on identified gene models

Association of Calcineurin with the COPI Protein Sec28 and the COPII Protein Sec13 Revealed by Quantitative Proteomics

Calcineurin is a calcium-calmodulin-dependent serine/threonine specific protein phosphatase operating in key cellular processes governing responses to extracellular cues. Calcineurin is essential for growth at high temperature and virulence of the human fungal pathogen Cryptococcus neoformans but the underlying mechanism is unknown. We performed a mass spectrometry analysis to identify proteins that associate with the calcineurin A catalytic subunit (Cna1) in C. neoformans cells grown under non-stress and high temperature stress conditions. A novel prioritization strategy for mass spectrometry data from immunoprecipitation experiments identified putative substrates and proteins potentially operating with calcineurin in common pathways. Cna1 co-purified with proteins involved in membrane trafficking including the COPI component Sec28 and the COPII component Sec13. The association of Cna1 with Sec28 and Sec13 was confirmed by co-immunoprecipitation. Cna1 exhibited a dramatic change in subcellular localization during high temperature stress from diffuse cytoplasmic to ER-associated puncta and the mother-bud neck and co-localized with Sec28 and Sec13

Linking protein fractionation with multidimensional monolithic reversed-phase peptide chromatography/mass spectrometry enhances protein identification from complex mixtures even in the presence of abundant proteins

Recently, multidimensional shotgun proteomics has proven to be an alternative technology able to identify hundreds of proteins from single samples. Two major limitations of the technology are the presence of high abundance proteins (e.g. RUBISCO in plant leaf tissue) and the enormous number of co-eluting peptides that overstrain the loading and resolving capacity of conventional particle-packed columns as well as the capacity of electrospray ionisation due to ion suppression. Here, the coupling of fast performance liquid chromatography (FPLC) pre-fractionation of an Arabidopsis leaf protein extract and subsequent two-dimensional liquid chromatography/mass spectrometry with improved resolution using a monolithic silica C18 capillary column allowed the identification of 1032 unique proteins in a single 4 mg total protein plant leaf tissue sample. The reassignment of peptide IDs to distinct FPLC protein fractions enhances the identification procedure, especially in the case of present protein isoforms. The proposed strategy is useful to detect proteins otherwise not seen in conventional multidimensional chromatography/mass spectrometry approaches. Copyright (C) 2004 John Wiley Sons, Ltd