Isolation of native plasma membrane H⁺-ATPase (Pma1p) in both the active and basal activation states

The yeast plasma membrane H(+)-ATPase Pma1p is a P-type ATPase that energizes the yeast plasma membrane. Pma1p exists in two activation states: an autoinhibited basal state and an activated state. Here we show that functional and stable Pma1p can be purified in native form and reconstituted in artificial liposomes without altering its activation state. Acetylated tubulin has previously been reported to maintain Pma1p in the basal state but, as this protein was absent from the purified preparations, it cannot be an essential component of the autoinhibitory mechanism. Purification of and reconstitution of native Pma1p in both activation states opens up for a direct comparison of the transport properties of these states, which allowed us to confirm that the basal state has a low coupling ratio between ATP hydrolysis and protons pumped, whereas the activated state has a high coupling ratio. The ability to prepare native Pma1p in both activation states will facilitate further structural and biochemical studies examining the mechanism by which plasma membrane H(+)-ATPases are autoinhibited

Enzyme Sequence and Its Relationship to Hyperbaric Stability of Artificial and Natural Fish Lactate Dehydrogenases

The cDNAs of lactate dehydrogenase b (LDH-b) from both deep-sea and shallow living fish species, Corphaenoides armatus and Gadus morhua respectively, have been isolated, sequenced and their encoded products overproduced as recombinant enzymes in E. coli. The proteins were characterised in terms of their kinetic and physical properties and their ability to withstand high pressures. Although the two proteins are very similar in terms of their primary structure, only 21 differences at the amino acid level exist between them, the enzyme from the deep-sea species has a significantly increased tolerance to pressure and a higher thermostability. It was possible to investigate whether the changes in the N-terminal or C-terminal regions played a greater role in barophilic adaptation by the construction of two chimeric enzymes by use of a common restriction site within the cDNAs. One of these hybrids was found to have even greater pressure stability than the recombinant enzyme from the deep-living fish species. It was possible to conclude that the major adaptive changes to pressure tolerance must be located in the N-terminal region of the protein. The types of changes that are found and their spatial location within the protein structure are discussed. An analysis of the kinetic parameters of the enzymes suggests that there is clearly a trade off between Km and kcat values, which likely reflects the necessity of the deep-sea enzyme to operate at low temperatures

Self-Association of an Activating Natural Killer Cell Receptor, KIR2DS1

As a major component of the innate immune system, natural killer cells are responsible for activating the cytolytic killing of certain pathogen-infected or tumor cells. The self-recognition of natural killer cells is achieved in part by the killer cell immunoglobulin-like receptors (KIRs) protein family. In the current study, using a suite of biophysical methods, we investigate the self-association of an activating KIR, KIR2DS1. This KIR is of particular interest because when in the presence of the HLA-Cw6 protein, KIR2DS1 becomes a major risk factor for psoriasis, an autoimmune chronic skin disease. Using circular dichroism spectroscopy, dynamic light scattering, and atomic force microscopy, we reveal that KIR2DS1 self-associates in a well-defined fashion. Our novel results on an activating KIR allow us to suggest a working model for the KIR2DS1- HLA class I molecular mechanism

A Standardised Procedure for Evaluating Creative Systems: Computational Creativity Evaluation Based on What it is to be Creative

Computational creativity is a flourishing research area, with a variety of creative systems being produced and developed. Creativity evaluation has not kept pace with system development with an evident lack of systematic evaluation of the creativity of these systems in the literature. This is partially due to difficulties in defining what it means for a computer to be creative; indeed, there is no consensus on this for human creativity, let alone its computational equivalent. This paper proposes a Standardised Procedure for Evaluating Creative Systems (SPECS). SPECS is a three-step process: stating what it means for a particular computational system to be creative, deriving and performing tests based on these statements. To assist this process, the paper offers a collection of key components of creativity, identified empirically from discussions of human and computational creativity. Using this approach, the SPECS methodology is demonstrated through a comparative case study evaluating computational creativity systems that improvise music

OPV strains circulation in HIV infected infants after National Immunisation Days in Bangui, Central African Republic

<p>Abstract</p> <p>Background</p> <p>Humans are the only host of polioviruses, thus the prospects of global polio eradication look reasonable. However, individuals with immunodeficiencies were shown to excrete vaccine derived poliovirus for long periods of time which led to reluctance to prolong the vaccination campaign for fear of this end result. Therefore, we aimed to assess the duration of excretion of poliovirus after the 2001 National Immunization Days according to Human immunodeficiency virus status.</p> <p>Findings</p> <p>Fifty three children were enrolled. Sequential stool samples were collected in between National Immunisation Days rounds and then every month during one year. Children were classified into 2 groups: no immunodepression (n = 38), immunodepression (n = 15) according to CD4+ lymphocytes cells count. Thirteen poliovirus strains were isolated from 11 children: 5 Human immunodeficiency virus positive and 6 Human immunodeficiency virus negative. None of the children excreted poliovirus for more than 4 weeks. The restriction fragment length polymorphism analysis showed that all strains were of Sabin origin including a unique Polio Sabine Vaccine types 2 and 3 (S2/S3) recombinant.</p> <p>Conclusions</p> <p>From these findings we assume that Human immunodeficiency virus positive children are not a high risk population for long term poliovirus excretion. More powerful studies are needed to confirm our findings.</p

Litterfall, litter decomposition and associated nutrient fluxes in Pinus halepensis: influence of tree removal intensity in a Mediterranean forest

The online version of this article (doi:10.1007/s10342-015-0893-z) contains supplementary material, which is available to authorized users[EN] Our knowledge about the influence of silvicultural treatments on nutrient cycling processes in Mediterranean forests is still limited. Four levels of tree removal were compared in an Aleppo pine forest in eastern Spain to determine the effects on litterfall, litter decomposition and the associated nutrient fluxes after 12 years. Removal treatments included clearfelling, two shelterwood intensities (60 and 75 % of basal area removed) and untreated controls. Twelve years later, the basal area removed still explained 60 % of litterfall mass variance and 60 % of C, 52 % of N, 45 % of P, 17 % of K, 47 % of Ca and 60 % of Mg return variances. Litter decomposed somewhat more slowly in clearfellings compared to controls (p = 0.049), accumulated more Ca and released less K compared to the other three treatments. This was explained by contamination with mineral particles due to the poorly developed O horizon in clearfellings. We conclude that the management practices reduced the nutrient return via litterfall, but the nutrient release through decomposition seems poorly sensitive to canopy disturbance. In order to accurately quantify the harvesting impacts on nutrient cycling in this Mediterranean forest system, it is necessary to measure the litterfall of the understory layer.This work has been supported by a fellowship from the Generalitat Valenciana, Conselleria de Educacion, Formacion y Empleo awarded to L. Lado-Monserrat (BFPI/2008/041). Silvicultural treatments were carried out by the Mediterranean Centre for Environmental Studies (CEAM) through programme "I + D en relacion con la restauracion de la cubierta vegetal y otros aspectos de investigacion forestal". Dataloggers and probes were provided by the Generalitat Valenciana through Project "Efecto de diferentes sistemas de aclareo de masa forestal sobre la disponibilidad de agua, nutrientes y la regeneracion de la masa arborea y arbustiva en parcelas de pinar" (GV06/126). We acknowledge Joana Oliver, Ruth M. Tavera and Daniel Fortanet for their help in the laboratory and in the field. The authors wish to thank Francisco Galiana for his assistance, including help in fieldwork and providing information about the experimental design of the silvicultural treatments. Thanks also go to Rafael Herrera from the Centro de Ecologia, Instituto Venezolano de Investigaciones Cientificas, Caracas, Venezuela and two anonymous reviewers for critically reviewing the manuscript.Lado Monserrat, L.; Lidón, A.; Bautista, I. (2015). Litterfall, litter decomposition and associated nutrient fluxes in Pinus halepensis: influence of tree removal intensity in a Mediterranean forest. European Journal of Forest Research. 134(5):833-844. https://doi.org/10.1007/s10342-015-0893-zS8338441345Almagro M, Martínez-Mena M (2012) Exploring short-term leaf-litter decomposition dynamics in a Mediterranean ecosystem: dependence on litter type and site conditions. Plant Soil 358:323–335Alvarez A, Gracia M, Vayreda J, Retana J (2012) Patterns of fuel types and crown fire potential in Pinus halepensis forests in the Western Mediterranean Basin. For Ecol Manage 270:282–290Austin AT, Vivanco L (2006) Plant litter decomposition in a semi-arid ecosystem controlled by photodegradation. Nature 442:555–558Bates JD, Svejcar TS, Miller RF (2007) Litter decomposition in cut and uncut western juniper woodlands. J Arid Environ 70:222–236Binkley D (2008) Three key points in the design of forest experiments. For Ecol Manage 255:2022–2023Blair JM, Crossley DA Jr (1988) Litter decomposition, nitrogen dynamics and litter microarthropods in a southern Appalachian hardwood forest 8 years following clearcutting. J Appl Ecol 25:683–698Blanco JA, Zavala MA, Imbert JB, Castillo FJ (2005) Sustainability of forest management practices: evaluation through a simulation model of nutrient cycling. For Ecol Manage 213:209–228Blanco JA, Imbert JB, Castillo FJ (2006) Influence of site characteristics and thinning intensity on litterfall production in two Pinus sylvestris L. forests in the western Pyrenees. For Ecol Manage 237:342–352Blanco JA, Imbert JB, Castillo FJ (2008) Nutrient return via litterfall in two contrasting Pinus sylvestris forests in the Pyrenees under different thinning intensities. For Ecol Manage 256:1840–1852Blanco JA, Imbert JB, Castillo FJ (2011) Thinning affects Pinus sylvestris needle decomposition rates and chemistry differently depending on site conditions. Biogeochemistry 106:397–414Caldentey J, Ibarra M, Hernández J (2001) Litter fluxes and decomposition in Nothofagus pumilio stands in the region of Magallanes, Chile. For Ecol Manage 148:145–157Christensen JH, Krishna Kumar K, et al. (2013) Climate phenomena and their relevance for future regional climate change. In: Stocker TF, Qin D, Plattner G-K et al (Eds.) Climate change 2013: the physical science basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USACortina J, Vallejo VR (1994) Effects of clearfelling on forest floor accumulation and litter decomposition in a radiata pine plantation. For Ecol Manage 70:299–310Entry JA, Rose CL, Cromack K Jr (1991) Litter decomposition and nutrient release in ectomycorrhizal mat soils of a Douglas fir ecosystem. Soil Biol Biochem 23:285–290Fabbio G, Merlo M, Tosi V (2003) Silvicultural management in maintaining biodiversity and resistance of forests in Europe—the Mediterranean region. J Environ Manage 67:67–76Galiana F, Pérez-Badía R, Camarero E, Estruch V, Currás R (2001) Estimación de la Radiación solar incidente en pinares de Pinus halepensis sometidos a tratamientos selvícolas de cortas finales. In: Junta de Andalucía. Consejería de Medio Ambiente (Ed.) Actas del III Congreso Forestal Español. Junta de Andalucía. Granada (Original in Spanish)García-Plé C, Vanrell P, Morey M (1995) Litter fall and decomposition in a Pinus halepensis forest on Mallorca. J Veg Sci 6:17–22González Utrillas N, González Pérez E, Galiana F (2005) Variación del crecimiento diametral de la masa de pinar de carrasco en cortas finales experimentales, en los montes de Tuejar y Chelva (Valencia). IV Congreso Forestal Español. Zaragoza. Soc. Esp. Cien. For. (Original in Spanish)Guo LB, Sims REH (1999) Litter decomposition and nutrient release via litter decomposition in New Zealand eucalypt short rotation forests. Agric Ecosyst Environ 75:133–140GVA (1995) Mapa de Suelos de la Comunidad Valenciana. Chelva (666). Proyecto LUCDEME (Icona), Centro de Investigaciones sobre Desertificación y Conselleria d’Agricultura i Mig Ambient. Generalitat Valenciana. Valencia, Spain. (Original in Spanish)Hennessey TC, Dougherty PM, Cregg BM, Wittwer RF (1992) Annual variation in needle fall of a loblolly pine stand in relation to climate and stand density. For Ecol Manage 51:329–338Inagaki Y, Kuramoto S, Torii A, Shinomiya Y, Fukata H (2008) Effects of thinning on leaf-fall and leaf-litter nitrogen concentration in hinoki cypress (Chamaecyparis obtusa Endlicher) plantation stands in Japan. For Ecol Manage 255:1859–1867Jonard M, Misson L, Ponette Q (2006) Long-term thinning effects on the forest floor and the foliar nutrient status of Norway spruce stands in the Belgian Ardennes. Can J For Res 36:2684–2695Kim C, Sharik TL, Jurgensen MF (1996a) Canopy cover effects on mass loss, and nitrogen and phosphorus dynamics from decomposing litter in oak and pine stands in northern Lower Michigan. For Ecol Manage 80:13–20Kim C, Sharik TL, Jurgensen MF (1996b) Litterfall, nitrogen and phosphorus inputs at various levels of canopy removal in oak and pine stands in northern lower Michigan. Am Midl Nat 135:195–204Kim C, Son Y, Lee WK, Jeong J, Noh NJ, Kim SR, Yang AR, Ju NG (2012) Influence of forest tending (Soopkakkugi) works on litterfall and nutrient inputs in a Pinus densiflora stand. For Sci Technol 8:83–88Kimmins JP (2004) Forest ecology, a foundation for sustainable management and environmental ethics in forestry. Prentice-Hall, New JerseyKimmins JP, Mailly D, Seely B (1999) Modelling forest ecosystem net primary production: the hybrid simulation approach used in FORECAST. Ecol Modell 122:195–224Klemmedson JO, Meier CE, Campbell RE (1990) Litter fall transfers of dry matter and nutrients in ponderosa pine stands. Can J For Res 20:1105–1115Kunhamu TK, Kumar BM, Viswanath S (2009) Does thinning affect litterfall, litter decomposition, and associated nutrient release in Acacia mangium stands of Kerala in peninsular India? Can J For Res 39:792–801Lytle DE, Cronan CS (1998) Comparative soil CO2 evolution, litter decay, and root dynamics in clearcut and uncut spruce–fir forest. For Ecol Manage 103:121–128Molina AJ, Del Campo AD (2012) The effects of experimental thinning on throughfall and stemflow: a contribution towards hydrology-oriented silviculture in Aleppo pine plantations. For Ecol Manage 269:206–213Navarro FB, Romero-Freire A, Del Castillo T, Foronda A, Jiménez MN, Ripoll MA, Sánchez-Miranda A, Hutsinger L, Fernández-Ondoño E (2013) Effects of thinning on litterfall were found after years in a Pinus halepensis afforestation area at tree and stand levels. For Ecol Manage 289:354–362Olson JS (1963) Energy storage and the balance of producers and decomposers in ecological systems. Ecology 44:322–331Pérez Cueva AJ (1994) Atlas Climático de la Comunidad Valenciana. Colección Territori nº 4. Generalitat Valenciana. Conselleria d’Obres Publiques, Urbanisme i Transport, ValenciaPetritsch R, Hasenauer H, Pietsch SA (2007) Incorporating forest growth response to thinning within biome-BGC. For Ecol Manage 242:324–336Prescott CE (1997) Effects of clearcutting and alternative silvicultural systems on rates of decomposition and nitrogen mineralization in a coastal montane coniferous forest. For Ecol Manage 95:253–260Prescott CE (2002) The influence of the forest canopy on nutrient cycling. Tree Physiol 22:1193–1200Prescott CE, Blevins LL, Staley CL (2000) Effects of clear-cutting on decomposition rates of litter and forest floor in forests of British Columbia. Can J For Res 30:1751–1757Roig S, Del Río M, Cañellas I, Montero G (2005) Litter fall in Mediterranean Pinus pinaster Ait. stands under different thinning regimes. For Ecol Manage 206:179–190Sardans J, Peñuelas J, Rodà F (2005) Changes in nutrient use efficiency, status and retranslocation in young post-fire regeneration Pinus halepensis in response to sudden N and P input, irrigation and removal of competing vegetation. Trees 19:233–250Scarascia-Mugnozza G, Oswald H, Piussi P, Radoglou K (2000) Forests of the Mediterranean region: gaps in knowledge and research needs. For Ecol Manage 132:97–109Slovik S (1997) Tree physiology. In: Hüttl RF, Schaaf W (eds) Magnesium deficiency in forest ecosystems. Kluwer Academic Publishers, London, pp 101–214Taylor BR, Parkinson D (1988) Does repeated freezing and thawing accelerate decay of leaf litter? Soil Biol Biochem 20:657–665Torras O, Saura S (2008) Effects of silvicultural treatments on forest biodiversity indicators in the Mediterranean. For Ecol Manage 255:3322–3330Trofymow JA, Barclay HJ, McCullough KM (1991) Annual rates and elemental concentrations of litter fall in thinned and fertilized Douglas-fir. Can J For Res 21:1601–1615Wallace ES, Freedman B (1986) Forest floor dynamics in a chronosequence of hardwood stands in central Nova Scotia. Can J For Res 16:293–302Whitford WG, Meentemeyer V, Seastedt TR, Cromack Jr K, Crossley Jr DA, Santos P, Todd RL, Waide JB (1981) Exceptions to the AET model: deserts and clear-cut forest. Ecology 62:275–277Yin X, Perry JA, Dixon RK (1989) Influence of canopy removal on oak forest floor decomposition. Can J For Res 19:204–21

Harnessing the Creative Potential of Consumers: Money, Participation and Creativity in Idea Crowdsourcing

Given the growing importance of innovation and consumer engagement, many firms are strongly interested in finding ways to encourage their consumers to generate creative new product ideas for them in their crowdsourcing initiatives. To that end, managers often use monetary rewards – one of the most commonly used managerial tools to stimulate desired behaviors. A critical question in this respect is whether the use of monetary rewards is effective in stimulating creativity and, if so, how large those rewards should be. This study aims to answer these questions. The results of an experiment suggest that introducing monetary rewards does not contribute to the number of new product ideas generated by a single consumer or the novelty of his/her ideas, and when the reward is relatively small it can even be harmful. Monetary rewards, however, are effective in encouraging widespread participation in crowdsourcing initiatives and improving the appropriateness of the new product ideas. As a whole, these findings take us a step further toward better understanding the motivational mechanisms of consumer creativity in new product ideation

Age-dependent alterations in the inflammatory response to pulmonary challenge

The aging lung is increasingly susceptible to infectious disease. Changes in pulmonary physiology and function are common in older populations, and in those older than 60 years, pneumonia is the major cause of infectious death. Understanding age-related changes in the innate and adaptive immune systems, and how they affect both pulmonary and systemic responses to pulmonary challenge are critical to the development of novel therapeutic strategies for the treatment of the elderly patient. In this observational study, we examined age-associated differences in inflammatory responses to pulmonary challenge with cell wall components from Gram-positive bacteria. Thus, male Sprague-Dawley rats, aged 6 months or greater than 18 months (approximating humans of 20 and 55-65 years), were challenged, intratracheally, with lipoteichoic acid and peptidoglycan. Cellular and cytokine evaluations were performed on both bronchoalveolar lavage fluid (BAL) and plasma, 24 h post-challenge. The plasma concentration of free thyroxine, a marker of severity in non-thyroidal illness, was also evaluated. The older animals had an increased chemotactic gradient in favor of the airspaces, which was associated with a greater accumulation of neutrophils and protein. Furthermore, macrophage migration inhibitory factor (MIF), an inflammatory mediator and putative biomarker in acute lung injury, was increased in both the plasma and BAL of the older, but not young animals. Conversely, plasma free thyroxine, a natural inhibitor of MIF, was decreased in the older animals. These findings identify age-associated inflammatory/metabolic changes following pulmonary challenge that it may be possible to manipulate to improve outcome in the older, critically ill patient

Modelling creativity: identifying key components through a corpus-based approach

Creativity is a complex, multi-faceted concept encompassing a variety of related aspects, abilities, properties and behaviours. If we wish to study creativity scientifically, then a tractable and well-articulated model of creativity is required. Such a model would be of great value to researchers investigating the nature of creativity and in particular, those concerned with the evaluation of creative practice. This paper describes a unique approach to developing a suitable model of how creative behaviour emerges that is based on the words people use to describe the concept. Using techniques from the field of statistical natural language processing, we identify a collection of fourteen key components of creativity through an analysis of a corpus of academic papers on the topic. Words are identified which appear significantly often in connection with discussions of the concept. Using a measure of lexical similarity to help cluster these words, a number of distinct themes emerge, which collectively contribute to a comprehensive and multi-perspective model of creativity. The components provide an ontology of creativity: a set of building blocks which can be used to model creative practice in a variety of domains. The components have been employed in two case studies to evaluate the creativity of computational systems and have proven useful in articulating achievements of this work and directions for further research