One-step isolation and biochemical characterization of a highlyactive plant PSII monomeric core

We describe a one-step detergent solubilization protocol for isolating a highly active form of Photosystem II (PSII) from Pisum sativum L. Detailed characterization of the preparation showed that the complex was a monomer having no light harvesting proteins attached. This core reaction centre complex had, however, a range of low molecular mass intrinsic proteins as well as the chlorophyll binding proteins CP43 and CP47 and the reaction centre proteins D1 and D2. Of particular note was the presence of a stoichiometric level of PsbW, a low molecular weight protein not present in PSII of cyanobacteria. Despite the high oxygen evolution rate, the core complex did not retain the PsbQ extrinsic protein although there was close to a full complement of PsbO and PsbR and partial level of PsbP. However, reconstitution of PsbP and PsbPQ was possible. The presence of PsbP in absence of LHCII and other chlorophyll a/b binding proteins confirms that LHCII proteins are not a strict requirement for the assembly of this extrinsic polypeptide to the PSII core in contrast with the conclusion of Caffarri et al. (2009)

The K2K SciBar Detector

A new near detector, SciBar, for the K2K long-baseline neutrino oscillation expe riment was installed to improve the measurement of neutrino energy spectrum and to study neutrino interactions in the energy region around 1 GeV. SciBar is a 'fully active' tracking detector with fine segmentation consisting of plastic scintillator bars. The detector was constructed in summer 2003 and is taking data since October 2003. The basic design and initial performance is presented.Comment: 7 pages, 4figures, Contributed to Proceedings of the 10th Vienna Conference on Instrumentation, Vienna, February 16-21, 200

The metabolic syndrome is not associated with homocysteinemia: The Persian Gulf Healthy Heart Study

Background: It is uncertain whether homocysteine and the metabolic syndrome or its components are related in the general population, as studies investigating the association between homocysteine levels and insulin resistance have shown conflicting results. Methods: In an ancillary study to the Persian Gulf Healthy Heart Study, a cohort study of Iranian men and women aged ≥25 yr, a random sample of 1754 subjects were evaluated for the association of plasma homocysteine levels and the metabolic syndrome using National Cholesterol Education Program (NCEP)-Adult Treatment Panel (ATP)-III criteria. Total homocysteine levels and high sensitivity C-reactive protein (CRP) were determined by enzyme-linked immunosorbent assays. Results: Subjects with lower HDL-cholesterol and higher blood pressure showed significantly higher homocysteine levels (p=0.001 and p<0.0001; respectively). There was no significant difference in serum levels of homocysteine between subjects with and without the metabolic syndrome. In multiple logistic regression analysis, the metabolic syndrome did not show a significant association with serum homocysteine levels after adjusting for sex, age, smoking, fruit and vegetable intake pattern, body mass index, and physical inactivity. Concurrent elevated CRP levels and the metabolic syndrome also did not show a significant association with serum homocysteine levels after adjusting for sex, age, and lifestyle cardiovascular risk factors. Conclusions: There was no association between the metabolic syndrome using NCEP-ATPIII criteria and homocysteinemia in this study. These data refute the hypothesis that homocysteine levels are influenced by the metabolic syndrome, at least in general healthy population

The Escherichia coli transcriptome mostly consists of independently regulated modules

Underlying cellular responses is a transcriptional regulatory network (TRN) that modulates gene expression. A useful description of the TRN would decompose the transcriptome into targeted effects of individual transcriptional regulators. Here, we apply unsupervised machine learning to a diverse compendium of over 250 high-quality Escherichia coli RNA-seq datasets to identify 92 statistically independent signals that modulate the expression of specific gene sets. We show that 61 of these transcriptomic signals represent the effects of currently characterized transcriptional regulators. Condition-specific activation of signals is validated by exposure of E. coli to new environmental conditions. The resulting decomposition of the transcriptome provides: a mechanistic, systems-level, network-based explanation of responses to environmental and genetic perturbations; a guide to gene and regulator function discovery; and a basis for characterizing transcriptomic differences in multiple strains. Taken together, our results show that signal summation describes the composition of a model prokaryotic transcriptome

Debris Disks: Probing Planet Formation

Debris disks are the dust disks found around ~20% of nearby main sequence stars in far-IR surveys. They can be considered as descendants of protoplanetary disks or components of planetary systems, providing valuable information on circumstellar disk evolution and the outcome of planet formation. The debris disk population can be explained by the steady collisional erosion of planetesimal belts; population models constrain where (10-100au) and in what quantity (>1Mearth) planetesimals (>10km in size) typically form in protoplanetary disks. Gas is now seen long into the debris disk phase. Some of this is secondary implying planetesimals have a Solar System comet-like composition, but some systems may retain primordial gas. Ongoing planet formation processes are invoked for some debris disks, such as the continued growth of dwarf planets in an unstirred disk, or the growth of terrestrial planets through giant impacts. Planets imprint structure on debris disks in many ways; images of gaps, clumps, warps, eccentricities and other disk asymmetries, are readily explained by planets at >>5au. Hot dust in the region planets are commonly found (<5au) is seen for a growing number of stars. This dust usually originates in an outer belt (e.g., from exocomets), although an asteroid belt or recent collision is sometimes inferred.Comment: Invited review, accepted for publication in the 'Handbook of Exoplanets', eds. H.J. Deeg and J.A. Belmonte, Springer (2018

Immediate thoracotomy for penetrating injuries: Ten years' experience at a Dutch level I trauma center

Background: An emergency department thoracotomy (EDT) or an emergency thoracotomy (ET) in the operating theater are both beneficial in selected patients following thoracic penetrating injuries. Since outcome-descriptive European studies are lacking, the aim of this retrospective study was to evaluate ten years of experience at a Dutch level I trauma center. Method: Data on patients who underwent an immediate thoracotomy after sustaining a penetrating thoracic injury between October 2000 and January 2011 were collected from the trauma registry and hospital files. Descriptive and univariate analyses were performed. Results: Among 56 patients, 12 underwent an EDT and 44 an ET. Forty-six patients sustained one or multiple stab wounds, versus ten with one or multiple gunshot wounds. Patients who had undergone an EDT had a lower GCS (p < 0. 001), lower pre-hospital RTS and hospital triage RTS (p < 0. 001 and p = 0. 009, respectively), and a lower SBP (p = 0. 038). A witnessed loss of signs of life generally occurred in EDT patients and was accompanied by 100 % mortality. Survival following EDT was 25 %, which was significantly lower than in the ET group (75 %; p = 0. 002). Survivors had lower ISS (p = 0. 011), lower rates of pre-hospital (p = 0. 031) and hospital (p = 0. 003) hemodynamic instability, and a lower prevalence of concomitant abdominal injury (p = 0. 002). Conclusion: The overall survival rate in our study was 64 %. The outcome of immediate thoracotomy performed in this level I trauma center was similar to those obtained in high-incidence regions like the US and South Africa. This suggests that trauma units where immediate thoracotomies are not part of the daily routine can achieve similar results, if properly trained

Elevated Fibroblast growth factor 21 (FGF21) in obese, insulin resistant states is normalised by the synthetic retinoid Fenretinide in mice

The authors would like to thank undergraduate student Aleksandra Kowalczuk (University of Aberdeen) for assisting in experiments and Dr. Emma K. Lees (School of Health Sciences, Liverpool Hope University, Liverpool, UK) for invaluable discussions concerning the regulation of FGF21. We thank Dr. Calum Sutherland and Dr. Amy Cameron (both Division of Molecular and Clinical Medicine, Ninewells Hospital and Medical School, University of Dundee, Scotland, UK) for technical support and expertise in performing hepatocyte studies. Fenretinide was a generous gift of T. Martin (Johnson & Johnson, New Brunswick, NJ) and U. Thumeer (Cilag AG, Schaffhausen, Switzerland), for use completely without restriction or obligation. Quantitative-PCR was carried out using the qPCR Core Facility (Institute of Medical Sciences, University of Aberdeen). RNA-sequencing was carried out at the University of Aberdeen Centre for Genome Enabled Biology and Medicine. Pancreas histology was performed by Dr Linda Davidson (Department of Histology, Aberdeen Royal Infirmary, NHS Grampian, Foresterhill Health Campus, Aberdeen, UK). This study was supported by the British Heart Foundation Intermediate Basic Research Fellowship FS/09/026 to N. Mody, RCUK fellowship to MD, EFSD/Lilly Programme Grant to MD and N. Mody, Tenovus Scotland grants G10/04 and G14/14 to N. Mody, University of Aberdeen Centre for Genome Enabled Biology and Medicine (CGEBM) PhD studentship to N. Morrice and Biotechnology and Biological Sciences Research Council studentship to GDM.Peer reviewedPublisher PD

Glutamate mediated metabolic neutralization mitigates propionate toxicity in intracellular Mycobacterium tuberculosis

Metabolic networks in biological systems are interconnected, such that malfunctioning parts can be corrected by other parts within the network, a process termed adaptive metabolism. Unlike Bacillus Calmette-Guérin (BCG), Mycobacterium tuberculosis (Mtb) better manages its intracellular lifestyle by executing adaptive metabolism. Here, we used metabolomics and identified glutamate synthase (GltB/D) that converts glutamine to glutamate (Q → E) as a metabolic effort used to neutralize cytoplasmic pH that is acidified while consuming host propionate carbon through the methylcitrate cycle (MCC). Methylisocitrate lyase, the last step of the MCC, is intrinsically downregulated in BCG, leading to obstruction of carbon flux toward central carbon metabolism, accumulation of MCC intermediates, and interference with GltB/D mediated neutralizing activity against propionate toxicity. Indeed, vitamin B12 mediated bypass MCC and additional supplement of glutamate led to selectively correct the phenotypic attenuation in BCG and restore the adaptive capacity of BCG to the similar level of Mtb phenotype. Collectively, a defective crosstalk between MCC and Q → E contributes to attenuation of intracellular BCG. Furthermore, GltB/D inhibition enhances the level of propionate toxicity in Mtb. Thus, these findings revealed a new adaptive metabolism and propose GltB/D as a synergistic target to improve the antimicrobial outcomes of MCC inhibition in Mtb

Isolation of novel PSII-LHCII megacomplexes from pea plants characterized by a combination of proteomics and electron microscopy

This work was supported by the Italian Ministry of Education, University and Research, “Futuro in Ricerca 2013” program RBFR1334SB to CP