Pectinmethylesterase from the rice weevil, Sitophilus oryzae: cDNA isolation and sequencing, genetic origin, and expression of the recombinant enzyme

A cDNA clone encoding pectinmethylesterase of the rice weevil, Sitophilus oryzae (L.) has been isolated and sequenced. The cDNA clone was expressed in cultured insect cells and active pectinmethylesterase was purified from the culture medium, thus confirming that the cDNA encodes pectinmethylesterase. In situ hybridization indicated that the enzyme's transcript was present in the midgut. Weevils treated with tetracycline so that they lack genes of known symbiotic organisms still contained the pectinmethylesterase gene, indicating that the gene is encoded by the rice weevil genome. The rice weevil enzyme is most similar in sequence to bacterial pectinmethylesterases. Given this and the enzyme's apparently rather general absence from animal species, we suggest the possibility that this gene was transferred horizontally to an ancient weevil, possibly from a bacterial symbiont, and exists in Sitophilus species now as a result of that ancestral horizontal transfer

Efficient solar cells are more stable: The impact of polymer molecular weight on performance of organic photovoltaics

The principle remaining challenge in the research area of organic photovoltaic (OPV) materials is to develop solar cells that combine high efficiency, stability and reproducibility. Here, we demonstrate an experimental strategy which has successfully addressed this challenge. We produced a number of samples of the highly efficient PTB7 polymer with various molecular weights (Mn 40–220k). OPV cells fabricated with this polymer demonstrated significant improvement of the cell efficiency (by 90% relative) and lifetime (by 300% relative) with the Mn increase. We attribute these effects to the lower density of recombination centers (persistent radical defects revealed by EPR spectroscopy) and better photoactive layer morphology in the samples with higher Mn. Relevance of the observed correlation between the OPV efficiency and stability is discussed

Infections with Avian Pathogenic and Fecal Escherichia coli Strains Display Similar Lung Histopathology and Macrophage Apoptosis

The purpose of this study was to compare histopathological changes in the lungs of chickens infected with avian pathogenic (APEC) and avian fecal (Afecal) Escherichia coli strains, and to analyze how the interaction of the bacteria with avian macrophages relates to the outcome of the infection. Chickens were infected intratracheally with three APEC strains, MT78, IMT5155, and UEL17, and one non-pathogenic Afecal strain, IMT5104. The pathogenicity of the strains was assessed by isolating bacteria from lungs, kidneys, and spleens at 24 h post-infection (p.i.). Lungs were examined for histopathological changes at 12, 18, and 24 h p.i. Serial lung sections were stained with hematoxylin and eosin (HE), terminal deoxynucleotidyl dUTP nick end labeling (TUNEL) for detection of apoptotic cells, and an anti-O2 antibody for detection of MT78 and IMT5155. UEL17 and IMT5104 did not cause systemic infections and the extents of lung colonization were two orders of magnitude lower than for the septicemic strains MT78 and IMT5155, yet all four strains caused the same extent of inflammation in the lungs. The inflammation was localized; there were some congested areas next to unaffected areas. Only the inflamed regions became labeled with anti-O2 antibody. TUNEL labeling revealed the presence of apoptotic cells at 12 h p.i in the inflamed regions only, and before any necrotic foci could be seen. The TUNEL-positive cells were very likely dying heterophils, as evidenced by the purulent inflammation. Some of the dying cells observed in avian lungs in situ may also be macrophages, since all four avian E. coli induced caspase 3/7 activation in monolayers of HD11 avian macrophages. In summary, both pathogenic and non-pathogenic fecal strains of avian E. coli produce focal infections in the avian lung, and these are accompanied by inflammation and cell death in the infected areas

QUantitative Imaging of eXtraction of oxygen and TIssue consumption (QUIXOTIC) using venular-targeted velocity-selective spin labeling

available in PMC 2012 December 1While oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2) are fundamental parameters of brain health and function, a robust MRI-based mapping of OEF and CMRO2 amenable to functional MRI (fMRI) has not been established. To address this issue, a novel method called QUantitative Imaging of eXtraction of Oxygen and TIssue Consumption, or QUIXOTIC, is introduced. The key innovation in QUIXOTIC is the use of velocity-selective spin labeling to isolate MR signal exclusively from postcapillary venular blood on a voxel-by-voxel basis. Measuring the T2 of this venular-targeted blood allows calibration to venular oxygen saturation (Yv) via theoretical and experimental T2 versus blood oxygen saturation relationships. Yv is converted to OEF, and baseline CMRO2 is subsequently estimated from OEF and additional cerebral blood flow and hematocrit measurements. Theory behind the QUIXOTIC technique is presented, and implications of cutoff velocity (VCUTOFF) and outflow time parameters are discussed. Cortical gray matter values obtained with QUIXOTIC in 10 healthy volunteers are Yv = 0.73 ± 0.02, OEF = 0.26 ± 0.02, and CMRO2 = 125 ± 15 μmol/100 g min. Results are compared to global measures obtained with the T2 relaxation under spin tagging (TRUST) technique. The preliminary data presented suggest that QUIXOTIC will be useful for mapping Yv, OEF, and CMRO2, in both clinical and functional MRI settings.National Institutes of Health (U.S.) (NIH Neuroimaging Training Program Grant, 5-T32-EB001680)National Institutes of Health (U.S.) (NIH Neuroimaging Training Program Grant, 5-R01-EB002066-20)National Institutes of Health (U.S.) (Center for Functional Neuroimaging Technologies; Grant number: P41RR14075S10RR023401)Siemens Aktiengesellschaft (Siemens Medical Solutions)Harvard University--MIT Division of Health Sciences and Technology (Martinos Catalyst Fund)National Cancer Institute (U.S.) (NIH Grant number RO1 EB007942)National Institutes of Health (U.S.) (NIH Medical Scientist Training Program Fellowship, grant no. T32-GM07753

Air Exposure Induced Recombination in PTB7:PC₇₁BM Solar Cells

SAJT acknowledges studentship funding from EPSRC under grant number EP/G03673X/1. I. D. W. S. acknowledges support EPSRC (EP/L012294/1) and a Royal Society Wolfson Research Merit Award. S. C. H. acknowledges funding from EPSRC under grant number EP/J500045/1. We also acknowledge support from the Wellcome Trust (099149) and from EPSRC (EP/F039034/1)Understanding degradation pathways in organic photovoltaic cells (OPV) is essential to achieve long term device stability and allow commercialisation. Upon exposure to an ambient atmosphere the power conversion efficiency (PCE) of PTB7:PC71BM solar cells, cast using the solvent additive DIO, is markedly reduced. Using electrically detected magnetic resonance (EDMR) spectroscopy, trap sites, which are formed when the blend is exposed to air and DIO, are identified. Spin-Rabi oscillations reveal that the resonance arises from a weakly coupled pair of spin 1/2 species, while selective injection of charge carriers into the cell demonstrates that the spin-pair corresponds to recombination of electrons and holes. The recombination is assigned to holes on the PTB7 recombining with electrons localised to oxygen induced PC71BM trap sites.Publisher PDFPeer reviewe

Cosmological neutrinos

The current status of neutrino cosmology is reviewed, from the question of neutrino decoupling and the presence of sterile neutrinos to the effects of neutrinos on the cosmic microwave background and large scale structure. Particular emphasis is put on cosmological neutrino mass measurements.Comment: 21 pages, 4 figures, review for NJP focus issue on neutrino

Absence of evidence or evidence of absence: Reflecting on therapeutic implementations of attentional bias modification

Attentional bias modification (ABM) represents one of a number of cognitive bias modification techniques which are beginning to show promise as therapeutic interventions for emotional pathology. Numerous studies with both clinical and non-clinical populations have now demonstrated that ABM can reduce emotional vulnerability. However, some recent studies have failed to achieve change in either selective attention or emotional vulnerability using ABM methodologies, including a recent randomised controlled trial by Carlbring et al. Some have sought to represent such absence of evidence as a sound basis not to further pursue ABM as an online intervention. While these findings obviously raise questions about the specific conditions under which ABM procedures will produce therapeutic benefits, we suggest that the failure of some studies to modify selective attention does not challenge the theoretical and empirical basis of ABM. The present paper seeks to put these ABM failure s in perspective within the broader context of attentional bias modification research. In doing so it is apparent that the current findings and future prospects of ABM are in fact very promising, suggesting that more research in this area is warranted, not less

Organic Single-Crystalline Donor-Acceptor Heterojunctions with Ambipolar Band-Like Charge Transport for Photovoltaics

Solution-processed organic single-crystalline donor-acceptor heterojunctions (SCHJs) composed of N,N,N',N'-tetraphenylbenzidine (TPB) and phenyl-C61-butyric acid methyl ester ([60]PCBM) were successfully obtained and fundamental studies on its charge transport properties were demonstrated; Revealing the advantages of applying single-crystalline heterojunctions in photovoltaic devices. The SCHJs exhibited a balanced high-mobility ambipolar charge transport with both hole and electron mobility being more than one order magnitude higher than its thin-film heterojunction (TFHJ) counterparts. The difference between single-crystalline and thin-film heterojunctions in charge transport mechanisms was revealed, and we showed that SCHJs present a more favorable band-like charge transport properties at room temperature. Organic photovoltaics fabricated on SCHJs present much higher current density and a 32-times higher PCE than thin-film heterojunction devices. The present work, which outlined comprehensive advantages of single-crystalline heterojunctions in charge transport properties, should accelerate the application of organic single crystals for high performance photovoltaics

Reversal of contractility as a signature of self-organization in cytoskeletal bundles.

Funder: FP7 People: Marie-Curie Actions; FundRef: http://dx.doi.org/10.13039/100011264; Grant(s): PCIG12-GA-2012-334053Bundles of cytoskeletal filaments and molecular motors generate motion in living cells, and have internal structures ranging from very organized to apparently disordered. The mechanisms powering the disordered structures are debated, and existing models predominantly predict that they are contractile. We reexamine this prediction through a theoretical treatment of the interplay between three well-characterized internal dynamical processes in cytoskeletal bundles: filament assembly and disassembly, the attachement-detachment dynamics of motors and that of crosslinking proteins. The resulting self-organization is easily understood in terms of motor and crosslink localization, and allows for an extensive control of the active bundle mechanics, including reversals of the filaments' apparent velocities and the possibility of generating extension instead of contraction. This reversal mirrors some recent experimental observations, and provides a robust criterion to experimentally elucidate the underpinnings of both actomyosin activity and the dynamics of microtubule/motor assemblies in vitro as well as in diverse intracellular structures ranging from contractile bundles to the mitotic spindle

Deficiency in pulmonary surfactant proteins in mice with fatty acid binding protein 4‐ Cre ‐mediated knockout of the tuberous sclerosis complex 1 gene

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96661/1/expphysiol.2012.069674.pd