bluuebunny/crossref_metadata_2025_split huggingface dataset:
A lysophospholipase plays role in generation of neutral-lipids required for hemozoin formation in malaria parasite
Authors: Asad Mohd , Yamaryo-Botté Yoshiki , Hossain Mohammad E. , Thakur Vandana , Jain Shaifali , Datta Gaurav , Botté Cyrille Y. , Mohmmed Asif 
Published: October 2019

AbstractPhospholipid metabolism is crucial for membrane dynamics in malaria parasites during entire cycle in the host cell. Plasmodium falciparum harbours several members of phospholipase family, which play key role in phospholipid metabolism. Here we have functionally characterized a parasite lysophospholipase (PfLPL1) with a view to understand its role in lipid homeostasis. We used a regulated fluorescence affinity tagging, which allowed endogenous localization and transient knock-down of the protein. PffLPL1localizes to dynamic vesicular structures that traffic from parasite periphery, through the cytosol to get associated as a multi-vesicular neutral lipid rich body next to the food-vacuole during blood stages. Down-regulation of the PfLPL1 disrupted parasite lipid-homeostasis leading to significant reduction of neutral lipids in lipid-bodies. This hindered conversion of heme to hemozoin, leading to food-vacuole abnormalities, which in turn disrupted parasite development cycle and significantly inhibited parasite growth. Detailed lipidomic analyses of inducible knock-down parasites confirmed role of PfLPL1 in generation of neutral lipid through recycling of phospholipids. Our study thus suggests a specific role of PfLPL1 to generate neutral lipids in the parasite, which are essential for parasite survival.ImportancePresent study was undertaken with a view to understand the functional role of a unique lipase (lysophopholipase, PfLPL1) of the human malaria parasite. We utilized genetic approaches for GFP tagging as well as to knock-down the target protein in the parasite. Our studies showed that PfLPL1 associates closely with the lysosome like organelle in the parasite, the food-vacuole. During the blood stage parasite cycle, the food-vacuole is involved in degradation of host haemoglobin and conversion of heme to hemozoin. Genetic knock-down approaches and detailed lipidomic studies confirmed that PfLPL1 protein plays key role in generation of neutral lipid stores in the parasite; neutral lipids are essentially required for hemozoin formation in the parasite, a vital function of the food-vacuole. Overall, this study identified specific role of PfLPL1 in the parasite which is essential for parasite survival.
Midbody remnant inheritance is regulated by the ESCRT subunit CHMP4C
Authors: Casares-Arias Javier , Gonzalez María Ujué , San Paulo Alvaro , Ventimiglia Leandro N. , Sadler Jessica B. A. , Miguez David G. , Labat-de-Hoz Leticia , Rubio-Ramos Armando , Rangel Laura , Bernabé-Rubio Miguel , Fernández-Barrera Jaime , Correas Isabel , Martín-Serrano Juan , Alonso Miguel A. 
Published: October 2019

AbstractThe inheritance of the midbody remnant (MBR) breaks the symmetry of the two daughter cells, with functional consequences for lumen and primary cilium formation by polarized epithelial cells, and also for development and differentiation. However, despite their importance, neither the relationship between the plasma membrane and the inherited MBR nor the mechanism of MBR inheritance is well known. Here, the analysis by correlative light and ultra-high-resolution scanning electron microscopy reveals a membranous stalk that physically connects the MBR to the apical membrane of epithelial cells. The stalk, which derives from the uncleaved side of the midbody, concentrates the ESCRT machinery. The ESCRT CHMP4C subunit enables MBR inheritance, and its depletion dramatically reduces the percentage of ciliated cells. We demonstrate: (1) that MBRs are physically connected to the plasma membrane, (2) how CHMP4C helps maintain the integrity of the connection, and (3) the functional importance of the connection.
A photostable monomeric superfolder GFP
Authors: Valbuena Fernando , Fizgerald Ivy , Strack Rita L. , Andruska Neal , Smith Luke , Glick Benjamin S. 
Published: October 2019

ABSTRACTThe green fluorescent protein GFP from Aequorea victoria has been engineered extensively in the past to generate variants suitable for protein tagging. Early efforts produced the enhanced variant EGFP and its monomeric derivative mEGFP, which have useful photophysical properties, as well as superfolder GFP, which folds efficiently under adverse conditions. We previously generated msGFP, a monomeric superfolder derivative of EGFP. Unfortunately, compared to EGFP, msGFP and other superfolder GFP variants show faster photobleaching. We now describe msGFP2, which retains monomeric superfolder properties while being as photostable as EGFP. msGFP2 contains modified N- and C-terminal peptides that are expected to reduce nonspecific interactions. Compared to EGFP and mEGFP, msGFP2 is less prone to disturbing the functions of certain partner proteins. For general-purpose protein tagging, msGFP2 may be the best available derivative of A. victoria GFP.
Regulation of FXR1 by alternative splicing is required for muscle development and controls liquid-like condensates in muscle cells
Authors: Smith Jean A. , Curry Ennessa G. , Blue R. Eric , Roden Christine , Dundon Samantha E. R. , Rodríguez-Vargas Anthony , Jordan Danielle C. , Chen Xiaomin , Lyons Shawn M. , Crutchley John , Anderson Paul , Horb Marko E. , Gladfelter Amy S. , Giudice Jimena 
Published: October 2019

SUMMARYFragile-X mental retardation autosomal homolog-1 (FXR1) is a muscle-enriched RNA-binding protein. FXR1 depletion is perinatally lethal in mice, Xenopus, and zebrafish; however, the mechanisms driving these phenotypes remain unclear. The FXR1 gene undergoes alternative splicing, producing multiple protein isoforms and mis-splicing has been implicated in disease. Furthermore, mutations that cause frameshifts in muscle-specific isoforms result in congenital multi-minicore myopathy. We observed that FXR1 alternative splicing is pronounced in the serine and arginine-rich intrinsically-disordered domain; these domains are known to promote biomolecular condensation. Here, we show that tissue-specific splicing of fxr1 is required for Xenopus development and alters the disordered domain of FXR1. FXR1 isoforms vary in the formation of RNA-dependent biomolecular condensates in cells and in vitro. This work shows that regulation of tissue-specific splicing can influence FXR1 condensates in muscle development and how mis-splicing promotes disease.HIGHLIGHTSThe muscle-specific exon 15 impacts FXR1 functionsAlternative splicing of FXR1 is tissue- and developmental stage specificFXR1 forms RNA-dependent condensatesSplicing regulation changes FXR1 condensate properties
Method for optimal conflict-free aircraft trajectory generation
Authors: Han Yun-Xiang , Zhang Jian-Wei , Huang Xiao-Qiong 
Published: October 2019

Purpose
A number of automated tools will be required for the purpose of enabling efficient services in air traffic control. The purpose of this paper is to devise an optimal flight trajectory search method that optimizes airspace system efficiency for 3D space in the presence of uncertainties.

Design/methodology/approach
This paper put forward an optimization model for generating applicable solutions of multi-aircraft conflict resolution problem, and the solution is based on the principle of optimality.

Findings
The conflict resolution problem between multiple aircraft can be described by spatial discretization, and the approach taken digitizes the 3D space into a grid of nodes.

Practical implications
The simulation examples are given to illustrate the validity of trajectory search model and stress on the impact of different system parameters.

Originality/value
Realistic constraints that are convenient to operate are incorporated in the system model, and the results show that it can provide reliable decision-making for conflict avoidance.
Multi-layered optimal navigation system for quadrotor UAV
Authors: Choutri Kheireddine , Lagha Mohand , Dala Laurent 
Published: October 2019

Purpose
This paper aims to propose a new multi-layered optimal navigation system that jointly optimizes the energy consumption, improves the robustness and raises the performance of a quadrotor unmanned aerial vehicle (UAV).

Design/methodology/approach
The proposed system is designed as a multi-layered system. First, the control architecture layer links the input and the output spaces via quaternion-based differential flatness equations. Then, the trajectory generation layer determines the optimal reference path and avoids obstacles to secure the UAV from collisions. Finally, the control layer allows the quadrotor to track the generated path and guarantees the stability using a double loop non-linear optimal backstepping controller (OBS).

Findings
All the obtained results are confirmed using several scenarios in different situations to prove the accuracy, energy optimization and the robustness of the designed system.

Practical implications
The proposed controllers are easily implementable on-board and are computationally efficient.

Originality/value
The originality of this research is the design of a multi-layered optimal navigation system for quadrotor UAV. The proposed control architecture presents a direct relation between the states and their derivatives, which then simplifies the trajectory generation problem. Furthermore, the derived differentially flat equations allow optimization to occur within the output space as opposed to the control space. This is beneficial because constraints such as obstacle avoidance occur in the output space; hence, the computation time for constraint handling is reduced. For the OBS, the novelty is that all controller parameters are derived using the multi-objective genetic algorithm (MO-GA) that optimizes all the quadrotor state’s cost functions jointly.
Understanding complementarities among different forms of innovation
Authors: Torres Pedro , Augusto Mário 
Published: October 2019

PurposeThe purpose of this paper is to better understand complementarities-in-performance of three forms of innovations: product innovation, process innovation and organizational innovation. Additionally, complementarities-in-use for product innovation are examined, considering an additional condition: manufacturing flexibility.Design/methodology/approachUsing data from 223 unlisted Portuguese industrial firms, and a fuzzy-set qualitative comparative analysis, different combinations of different forms of innovations were examined to identify complementarities-in-performance and complementarities-in-use.FindingsThrough the configurational analysis, a path to achieve high performance was uncovered, which includes the presence of both product and organizational innovations. The study also reveals that the joint absence of two conditions (from the three that were considered in the analysis) can lead to low performance. This result indicates that the relationships among the antecedent conditions are non-linear. The configurational analysis also shows that the combination of manufacturing flexibility with either process innovation or organizational innovation can lead to high product innovation. This result confirms that manufacturing flexibility is an important condition for product innovation.Research limitations/implicationsThe empirical evidence reported in this paper may be influenced by the definitions that were considered. Further conceptual and empirical research is encouraged to corroborate (or refute) or consolidate the findings presented herein. Moreover, although the obtained results present a high empirical coverage, other antecedent conditions beyond the scope of this study can also play an important role; for instance, marketing could influence innovation performance. Furthermore, radical innovation was not distinguished from incremental innovation when analyzing firm performance.Practical implicationsThis study provides some clues for policy makers who aim to enhance firm performance through innovation. Managers should focus on both organizational and technological innovations, in particular product innovation, to improve firm performance. Moreover, they should be aware of the complementarities-in-use for product innovation. Considering the importance of developing product innovation to enhance performance, firms should promote high levels of product innovation. To achieve this outcome, manufacturing flexibility should be present.Originality/valueFocusing on a very complex and still under-researched topic, this study contributes to the complementarities literature in several ways. This study employs a configurational approach to better understand complementarities and to integrate technological and organizational innovations. By taking this approach, this study acknowledges the existence of non-linearity and identifies not only the strategies to achieve high performance, but also the configurations that lead to low performance.
Examining the relationship between organizational commitment and turnover intention via a meta-analysis
Authors: Guzeller Cem Oktay , Celiker Nuri 
Published: October 2019

PurposeThe purpose of this study is expected to reveal the relationship between organizational commitment and turnover intention in the tourism and hospitality literature with more generalizable results, and thus, provide researchers with a new perspective for future studies. In this context, Individual studies that examined the relationship between organizational commitment and turnover intention in the tourism and hospitality industry were systematically identified by a comprehensive literature review.Design/methodology/approachIndividual studies were synthesized and analyzed via a meta-analysis method to reveal whether any relationship exists between organizational commitment and turnover intention and to estimate the direction and intensity of the relationship in a more reliable and comprehensive manner. The analyses were carried out on 13 scientific papers that met the inclusion criteria.FindingsResults showed that a moderate negative relationship exists between organizational commitment and turnover intention of employees in the tourism and hospitality industry. In this context, individuals who have emotional commitments to their institutions will have lower turnover intentions than others. The right personal selection, performance evaluation techniques, promotion, training and development opportunities, career opportunities and talent management and functional virtues such as strong communication, trust and justice will not only reinforce organizational commitment but also attract talented individuals to an organization and ensure employee retention.Originality/valueIn the current study, individual studies focusing on the relationship between organizational commitment and turnover were cumulatively collected, synthesized and analyzed. By way of providing a review of individual studies, the study provides cumulative and reliable evidence to the literature regarding the relationship between organizational commitment and turnover, and hence, contributes to the further progression of the field. The study is also the first meta-analysis carried out on the subject in question.
Effects of brand exposure time duration and frequency on image transfer in sport sponsorship
Authors: Kwon Hyungil , Shin Jae Eun 
Published: October 2019

PurposeThe purpose of this paper is to explore the moderating effect of brand exposure time and exposure frequency in image transfer. In study 1,H1andH2assumed the bidirectional image transfer (i.e. from an event to a brand, from a brand to an event).H3andH4were set to examine the moderating effect of brand exposure time and exposure frequency in image transfer upon spreading activation theory, mere exposure effect and three-hit theory.Design/methodology/approachAccording to study 1, the result indicated that the amount of image transfer varied based on the exposure time. However, brand exposure frequency did not show statistically significant interactions. Study 2 was performed to complement theH4of the study 1. In study 2, apart from the number of exposures on a screen (group 1=four times; group 2=eight times), the perceived number of exposures were separately measured (group 1=2.67; group 2=3.96) to see if the number of perceived exposures moderated the amount of image transfer.FindingsThe results indicated that there was no group difference in the amount of image transfer. Based on the result of the study, a sponsor brand must be exposed for enough time duration in order to maximize the return on investment regardless of how frequently it is exposed.Originality/valueThe current study examined the image transfer in sport sponsorship. Although previous studies empirically examined the image transfer phenomenon in sport sponsorship, they failed to establish theoretical ground. Thus, this study incorporated the three theories in advertising and examined how we can apply the theories to sport sponsorship. In addition, we examine the image transfer based on video clip which is mainly how people are exposed to sport sponsorship. Next, we examined the moderating effects of exposure duration and exposure frequency, which has never been studied in sport sponsorship context.
Multiple facets of diversity effects on plant productivity: Species richness, functional diversity, species identity and intraspecific competition
Authors: Mahaut Lucie , Fort Florian , Violle Cyrille , Freschet Grégoire T. 
Published: October 2019

Abstract

Deciphering the mechanisms that drive variation in biomass production across plant communities of contrasting species composition and diversity is a main challenge of biodiversity–ecosystem functioning research. Niche complementarity and selection effect have been widely investigated to address biodiversity–productivity relationships. However, the overlooking of the specific role played by key species has limited so far our capacity to comprehensively assess the relative importance of other potential drivers of biodiversity effects.

Here, we conducted a grassland diversity–productivity experiment to test how four potential facets of biodiversity effects, namely species richness, functional diversity, species identity and the relaxation of intraspecific competition, account for variations in above and root biomass production.

We grew six plant species in monoculture, as well as in every combination of two, three and six species. Plant density was kept constant across the richness gradient but we additionally grew each species in half‐density monoculture to estimate the strength of intraspecific competition for each studied species. We characterized eight functional traits, including root traits, related to nutrient and light acquisition and computed both the functional dissimilarity and the community‐weighted mean (CWM) of each trait. We further partitioned above‐ground biodiversity effect into complementarity and selection effects.

We observed strong positive biodiversity effects on both above‐ground and root biomass as well as strong positive complementarity effect. These arose largely from the presence of a particular species (Plantago lanceolata) and from CWM trait values more than from a higher functional dissimilarity in plant mixtures. P. lanceolata displayed the highest intraspecific competition, which was strongly relaxed in species mixtures. By contrast, the presence of Sanguisorba minor negatively affected the productivity of plant mixtures, this species suffering more from interspecific than intraspecific competition.

This study provides strong evidences that the search for key species is critical to understand the role of species diversity on ecosystem functioning and demonstrates the major role that the balance between intraspecific and interspecific competition plays in biodiversity–ecosystem functioning relationships. Developing more integrative approaches in community and ecosystem ecology can offer opportunities to better understand the role that species diversity plays on ecosystem functioning.

A free Plain Language Summary can be found within the Supporting Information of this article.
Predicting reintroduction costs for wildlife populations under anthropogenic stress
Authors: Hilbers Jelle P. , Huijbregts Mark A. J. , Schipper Aafke M. 
Published: October 2019

Abstract

In conservation decision‐making, it is important to have information not only on the likely effectiveness of conservation actions, but also on the corresponding costs. Reintroduction of wildlife is a commonly applied ‘last resort’ conservation measure. However, a quantitative approach to predict the costs of reintroduction for sustaining a wildlife population under the influence of time‐varying anthropogenic stress is lacking.

Here, we fill this gap by quantifying the costs of reintroduction as a function of exposure to an environmental stressor and the size of the wildlife population to be maintained. Our approach combines quantitative stressor–response relationships for vital rates (reproduction and survival) with a wildlife demographic model to compute the impacts of the stressor on the size of the target population. Subsequently, cost estimates are obtained by quantifying the number of captive‐reared individuals needed per year in order to maintain a user‐defined population size, given the exposure to the stressor of concern. We applied our approach to calculate the reintroduction costs required to restore a minimum viable population (MVP) of peregrine falcons (Falco peregrinus) in California over the period 1970–1994, when the population was exposed to the toxicant dichlorodiphenyldichloroethylene.

Assuming a gradual yearly increase of 150% in the availability of captive‐reared young, 1,753 captive‐reared young were required to restore and maintain a MVP of 238 adults. The corresponding reintroduction costs were in total ~$3,023,000. Assuming lower reintroduction efforts (in terms of the availability of captive‐reared young), the projected reintroduction costs decreased by ~33%. However, the population then reached the minimum viable size only 9 years later, thus reflecting a trade‐off between costs and population viability.

Synthesis and applications. The approach presented in this study ensures an adequate prediction of the costs of maintaining a wildlife population at a user‐defined size through reintroduction. It can be applied to any wildlife population in order to obtain the number of individuals and corresponding costs required to sustain a population under current and future influence of an anthropogenic stressor. This type of information provides important input for decision‐making necessary to conserve biodiversity.