bluuebunny/crossref_metadata_2025 huggingface dataset:
Contrasting signatures of introgression in North American box turtle (Terrapenespp.) contact zones
Authors: Martin Bradley T. , Douglas Marlis R. , Chafin Tyler K. , Placyk John S. , Birkhead Roger D. , Phillips Christopher A. , Douglas Michael E.
Published: September 2019

Hybridization occurs differentially across the genome in a balancing act between selection and migration. With the unprecedented resolution of contemporary sequencing technologies, selection and migration can now be effectively quantified such that researchers can identify genetic elements involved in introgression. Furthermore, genomic patterns can now be associated with ecologically relevant phenotypes, given availability of annotated reference genomes. We do so in North American box turtles (Terrapene) by deciphering how selection affects hybrid zones at the interface of species boundaries and identifying genetic regions potentially under selection that may relate to thermal adaptations. Such genes may impact physiological pathways involved in temperature-dependent sex determination, immune system functioning, and hypoxia tolerance. We contrasted these patterns across inter- and intra-specific hybrid zones that differ temporally and biogeographically. We demonstrate hybridization is broadly apparent inTerrapene, but with observed genomic cline patterns corresponding to species boundaries at loci potentially associated with thermal adaptation. These loci display signatures of directional introgression within intra-specific boundaries, despite a genome-wide selective trend against intergrades. In contrast, outlier loci for inter-specific comparisons exhibited evidence of being under selection against hybrids. Importantly, adaptations coinciding with species boundaries inTerrapeneoverlap with climatic boundaries and highlight the vulnerability of these terrestrial ectotherms to anthropogenic pressures.
A novel weight lifting task for investigating effort and persistence in rats
Authors: Porter Blake , Hillman Kristin L.
Published: September 2019

Here we present a novel effort-based task for laboratory rats: the weight lifting task (WLT). Studies of effort expenditure in rodents have typically involved climbing barriers within T-mazes or operant lever pressing paradigms. These task designs have been successful for neuropharmacological and neurophysiological investigations, but both tasks involve simple action patterns prone to automatization. Furthermore, high climbing barriers present risk of injury to animals and/or tethered recording equipment. In the WLT, a rat is placed in a large rectangular arena and tasked with pulling a rope 30 cm to trigger food delivery at a nearby spout; weights can be added to the rope in 45 g increments to increase the intensity of effort. As compared to lever pressing and barrier jumping, 30 cm of rope pulling is a multi-step action sequence requiring sustained effort. The actions are carried out on the single plane of the arena floor, making it safer for the animal and more suitable for tethered equipment and video tracking. A microcontroller and associated sensors enable precise timestamping of specific behaviors to synchronize with electrophysiological recordings. The rope and reward spout are spatially segregated to allow for spatial discrimination of the effort zone and the reward zone. We validated the task across five cohorts of rats (total n=35) and report consistent behavioral metrics. The WLT is well-suited for neuropharmacological and/or in vivo neurophysiological investigations surrounding effortful behaviors, particularly when wanting to probe different aspects of effort expenditure (intensity vs. duration).
Genetic Control of Radical Crosslinking in a Semi-Synthetic Hydrogel
Authors: Graham Austin J. , Dundas Christopher M. , Hillsley Alexander , Kasprak Dain S. , Rosales Adrianne M. , Keitz Benjamin K.
Published: September 2019

Enhancing materials with the qualities of living systems, including sensing, computation, and adaptation, is an important challenge in designing next-generation technologies. Living materials seek to address this challenge by incorporating live cells as actuating components that control material function. For abiotic materials, this requires new methods that couple genetic and metabolic processes to material properties. Toward this goal, we demonstrate that extracellular electron transfer (EET) fromShewanella oneidensiscan be leveraged to control radical crosslinking of a methacrylate-functionalized hyaluronic acid hydrogel. Crosslinking rates and hydrogel mechanics, specifically storage modulus, were dependent on a variety of chemical and biological factors, includingS. oneidensisgenotype. Bacteria remained viable and metabolically active in the crosslinked network for a least one week, while cell tracking revealed that EET genes also encode control over hydrogel microstructure. Moreover, construction of an inducible gene circuit allowed transcriptional control of storage modulus and crosslinking rate via the tailored expression of a key electron transfer protein, MtrC. Finally, we quantitatively modeled dependence of hydrogel stiffness on steady-state gene expression, and generalized this result by demonstrating the strong relationship between relative gene expression and material properties. This general mechanism for radical crosslinking provides a foundation for programming the form and function of synthetic materials through genetic control over extracellular electron transfer.

Significance Statement

Next-generation materials will require coupling the advantages of engineered and natural systems to solve complex challenges in energy, health, and the environment. Living cells, such as bacteria, naturally possess many of the qualities essential to addressing these challenges, including sensing, computation, and actuation, using their genetic and metabolic machinery. In addition, bacteria are attractive for incorporation into materials due to their durability, ease-of-use, and programmability. Here, we develop a platform for controlling hydrogel properties (e.g., stiffness, crosslinking rate) using extracellular electron transfer from the bacteriumShewanella oneidensis.In our system, metabolic electron flux fromS. oneidensisto a metal catalyst generates radical species that crosslink an acrylate-based macromer to form the gel. This synthetic reaction is under direct control of bacterial genetics and metabolism, which we demonstrate through inducible circuits and quantitative modeling of gene expression and resultant hydrogel properties. Developing methods that capitalize on the programmability of biological systems to control synthetic material properties will enable hybrid material designs with unprecedented functions.
Differential Striatal Axonal Arborizations of the Intratelencephalic and Pyramidal-Tract Neurons: Analysis of the Data in the MouseLight Database
Authors: Morita Kenji , Im Sanghun , Kawaguchi Yasuo
Published: September 2019

There exist two major types of striatum-targeting neocortical neurons, specifically, intratelencephalic (IT) neurons and pyramidal-tract (PT) neurons. Regarding their striatal projections, it was once suggested that IT axons are extended whereas PT axons are primarily focal. However, subsequent study with an increased number of well-stained extended axons concluded that such an apparent distinction was spurious due to limited sample size. Recent work using genetically labeled neurons reintroduced the differential spatial extent of the striatal projections of IT and PT neurons through population-level analyses, complemented by observations of single axons. However, quantitative analysis of a large number of axons remained to be conducted. We analyzed the data of axonal end-points of 161 IT neurons and 33 PT neurons in the MouseLight database (http://ml-neuronbrowser.janelia.org/). The number of axonal end-points in the ipsilateral striatum exhibits roughly monotonically decreasing distributions in both neuron types. However, the proportion of neurons having >50 ipsilateral end-points is larger in IT neurons than in PT neurons. Moreover, distinguishing IT subpopulations in the secondary motor area (MOs), layer 5 neurons and bilateral striatum-targeting layer 2/3 neurons, but not contralateral striatum-non-targeting layer 2/3 neurons, have a larger number of ipsilateral end-points than MOs PT neurons. We also found that IT ipsilateral striatal axonal end-points are on average more widely distributed than PT end-points, especially in the medial-lateral direction. These results indicate that IT and PT striatal axons differ in the frequency of having numerous end-points and the spatial extent of end-points while there are wide varieties within each neuron type.
The Influence of Blood Collection Tubes in Biomarkers Screening by Mass Spectrometry
Authors: Zhang Siyuan , Zhao Zixuan , Duan Wenjing , li Zhaoxin , Nan Zhuhui , Du Hanzhi , Wang Mengchang , Yang Juan , Huang Chen
Published: September 2019

Background

Mass spectrometry (MS) is one of the rapidly developing bio-analytical techniques in recent years and have found many biomarkers of variety of disease. Whereas pre-analytical process is one of most crucial procedure which would significantly influence the results of biomarkers screening. In the current study, we conducted a pilot analysis of serum to determine the effects of blood collection tubes in biomarkers screening.

Methods

Magnetic bead separation and matrix-assisted laser desorption ionization time-of-flight mass spectrometry were used for qualitative analysis of healthy control and serum cancer patients. A total of 24 serum samples were analyzed in this study, of which were collected from patients or healthy control using non-additive tubes or coagulant activator tubes respectively. ClinProTools were used to compare the difference among the different groups.

Results

The results demonstrated that no matter for patients or normal people, the serum protein profile changed significantly when using coagulant tubes. We also found that the effect of coagulant on serum protein of patients was smaller than that of control group. There were significant differences among 27 peaks which were obtained in the control group and the control coagulant group. However, between patient group and patient coagulant group, only 1 differential peak were obtained. Coagulant changed the protein expression difference in the original serum, and the difference expanded, narrowed even reversed, most of which are small polypeptides (Mass<3000 Da), which significantly changed the results of biomarkers screening. The results showed that 19 potential biomarkers could be found with non-additive tubes and 16 potential biomarkers could be found with coagulate activator tubes, among which only 6 were the same.

Conclusions

The choice of blood collection tube significantly influence the results of biomarkers screening by MS.
Stimulus-Specific Information Flow Across the Canonical Cortical Microcircuit
Authors: Tovar David A. , Westerberg Jacob A. , Cox Michele A. , Dougherty Kacie , Carlson Thomas , Wallace Mark T. , Maier Alexander
Published: September 2019

The vast majority of mammalian neocortex consists of a stereotypical microcircuit, the canonical cortical microcircuit (CCM), consisting of a granular input layer, positioned between superficial and deep layers. Due to this uniform layout, neuronal activation tends to follow a similar laminar sequence, with unique information extracted at each step. For example, the primate primary visual cortex (V1) combines the two eyes’ signals, extracts stimulus orientation and modulates its activity depending on stimulus history. Several theories have been proposed on when and where these processes happen within the CCM’s laminar activation sequence, but it has been methodologically challenging to test these hypotheses. Here, we use time-resolved multivariate pattern analysis (MVPA) to decode information regarding the eye-of-origin, stimulus orientation and stimulus repetition from simultaneously measured spiking responses across V1’s laminar microcircuit. We find that eye-of-origin information was decodable for the entire duration of stimulus presentation, but diminished in the deepest layers of V1, consistent with the notion that two eyes’ signals are combined within the upper layers. Conversely, orientation information was transient and equally pronounced across the microcircuit, in line with the idea that this information is relayed to other areas for further processing. Moreover, when stimuli were repeated, information regarding orientation was enhanced at the expense of eye-of origin information, suggesting that V1 modulates information flow to optimize specific stimulus dimensions. Taken together, these findings provide empirical evidence that adjudicates between long-standing hypotheses and reveals how information transfer within the CCM supports unique cortical functions.

Significance Statement

Despite the brain’s daunting complexity, there are common organizing principles across brain areas. For example, neocortical activation follows a stereotypical pattern that spreads from input layers towards layers above and below. While this activation pattern is well known, it has been challenging to ascertain how unique types of information are extracted within this common sequence in different brain areas. Here we use machine learning to track the flow of stimulus-specific information across the layers of visual cortex. We found that information regarding several separate stimulus dimensions was routed uniquely within the common activation sequence in a manner that confirmed prior model predictions. This finding demonstrates how differences in information flow within the stereotypical neocortical activation sequence shape area-specific functions.
Bacterial diversity in deep-sea sediments under influence of asphalt seep at the São Paulo Plateau
Authors: Queiroz Luciano Lopes , Gonçalves Bendia Amanda , Duarte Rubens Tadeu Delgado , das Graças Diego Assis , Costa da Silva Artur Luiz da , Nakayama Cristina Rossi , Sumida Paulo Yukio , Lima Andre O. S. , Nagano Yuriko , Fujikura Katsunori , Kitazato Hiroshi , Pellizari Vivian Helena
Published: September 2019

Here we investigated the diversity of bacterial communities from deep-sea surface sediments under influence of asphalt seeps at the Sao Paulo Plateau using next-generation sequencing (NGS) method. Sampling was performed at North São Paulo Plateau using the human occupied vehicle Shinkai 6500 and her support vessel Yokosuka. The microbial diversity was studied at two surficial sediment layers (0-1 and 1-4 cm) of five samples collected in cores in water depths ranging from 2,456-2,728 m. Bacterial communities were studied through sequencing of 16S rRNA gene on the Ion Torrent platform and clustered in operational taxonomic units. We observed high diversity of bacterial sediment communities as previously described by other studies. When we considered community composition, the most abundant classes were Alphaprotebacteria (27.7%), Acidimicrobiia (20%), Gammaproteobacteria (11.3%) and Deltaproteobacteria (6.6%). Most abundant OTUs at family level were from two uncultured bacteria from Actinomarinales (5.95%) and Kiloniellaceae (3.17%). The unexpected high abundance of Alphaproteobacteria and Acidimicrobiia in our deep-sea microbial communities may be related to the presence of asphalt seep at North São Paulo Plateau, since these bacterial classes contain bacteria that possess the capability of metabolizing hydrocarbon compounds.
CariogenicStreptococcus mutansproduces strain-specific antibiotics that impair commensal colonization
Authors: Tang Xiaoyu , Kudo Yuta , Baker Jonathon , LaBonte Sandra , Jordan Peter A. , McKinnie Shaun M. K. , Guo Jian , Huan Tao , Moore Bradley S. , Edlund Anna
Published: September 2019

Streptococcus mutansis a common constituent of dental plaque and an etiologic agent of dental caries (tooth decay). Here we elucidate a biosynthetic pathway, encoded by globally distributed strains ofS. mutans, which produces a series of bioactive small molecules including reutericyclin and twoN-acyl tetramic acid analogues active against oral commensal bacteria. This pathway may provideS. mutanswith a competitive advantage, promoting dysbiosis and caries pathogenesis.
Chronic pain alters microvascular architectural organization of somatosensory cortex
Authors: Zippo A.G. , Del Grosso V. , Patera A. , Riccardi M. P. , Tredici I. G. , Bertoli G. , Mittone A. , Valente M. , Stampanoni M. , Coan P. , Bravin A. , Biella G.E.M.
Published: September 2019

Chronic pain (CP) represents a complex pathology profoundly involving both neural and glial compartments of the central nervous system. While most CP studies have also investigated the macroscopic brain vascular system, its microstructural architecture still remains largely unexplored. Further, the adaptive modifications of the vascular microstructure as consequence of diseases or pathological insults, did not receive adequate attention. Here we show microtomographic signs of diffuse and conspicuous microvascular neogenesis in somatosensory cortex of CP animal models already peaking at 15 days from the model instantiation. Progressive fading of this microvessel neogenesis then ensued in the next six months yet maintaining higher vascular density with a preserved small fraction of them. Due to the important consequences on the neuron-glial-vessel arrangements and on the resulting metabolic and functional disorders of the local networks, novel additional scenarios of CP are thus conceivable with profound consequences of potential future CP diagnostic and therapeutic appraisals.
Sorting for CCR7-positivity enriches for a dendritic cell population with enhanced antigen-presenting capacity and anti-tumour potency
Authors: Burgoyne Paul , Hayes Alan J , Cooper Rachel S , Le Brocq Michelle L , Hansell Christopher A.H. , Campbell John DM , Graham Gerard J
Published: September 2019

Dendritic cell therapy has been a promising addition to the current armoury of therapeutic options in cancer for more than 20 years but has not yet achieved break-through success. To successfully initiate immunity, dendritic cells have to enter the lymph nodes. However, previous experience of therapeutic dendritic cell administration indicates that this is frequently an extremely inefficient process. The major regulator of dendritic cell migration to the lymph nodes is the chemokine receptor CCR7 and in vitro generated dendritic cells typically display heterogenous expression of this receptor. Here we demonstrate that positive-selection for the dendritic cell subpopulation expressing CCR7 enriches for cells with enhanced lymph node migration and antigen presentation competence as well as a chemokine expression profile indicative of improved interactions with T cells. In models of both subcutaneous and metastatic melanoma we demonstrate that the dendritic cells sorted for CCR7 expression trigger enhanced CD8 T-cell driven antitumour immune responses which correlate with reduced tumour burden and increased survival. Finally we demonstrate that this approach is directly translatable to human dendritic cell therapy using clinical-grade cell sorting.

Synopsis

Therapeutic dendritic cells drive anti-cancer immune responses but they migrate inefficiently to lymph nodes. We show that enriching for CCR7 expression yields a dendritic cellular product with enhanced ability to generate immune responses to localised and disseminated tumours.
Interaction between the assembly of the ribosomal subunits: Disruption of 40S ribosomal assembly causes accumulation of extra-ribosomal 60S ribosomal protein uL18/L5
Authors: Rahman Nusrat , Shamsuzzaman Md , Lindahl Lasse
Published: September 2019

Inhibition of the synthesis of a ribosomal protein (r-protein) abrogates the assembly of its cognate subunit, while assembly of the other subunit continues. Ribosomal components that are not stably incorporated into ribosomal particles due to the disrupted assembly are rapidly degraded. The 60S protein uL18/L5 is an exception, because this protein accumulates extra-ribosomally during inhibition of 60S assembly. Since the r-proteins in each ribosomal subunit are essential only for formation of their own subunit, it would be predicted that accumulation of extra-ribosomal uL18/5 only occurs during restriction of 60S assembly, and not during abolition of 40S assembly. Contrary to this prediction, we report here that repression of 40S r-protein genes does in fact lead to accumulation of uL18/L5 does outside the ribosome due modified 60S assembly. Furthermore, the effect varies depending on which 40S ribosomal protein is repressed. We propose that disruption of early steps in the 40S subunit assembly changes the kinetics of 60S subunit assembly resulting in a buildup of extra-ribosomal uL18/L5, even though 60S formation continues. Finally, our results show that maintenance of the pool of extra-ribosomal uL18/L5 requires continual protein synthesis showing that extra-ribosomal protein is not stable, but is slowly “consumed” by incorporation into 60S subunits and/or turnover.
Camelina (Camelina sativa L. Crantz) Crop Performance, Insect Pollinators, and Pollen Dispersal in the Northeastern US
Authors: Rizzitello Richard , Zhang Chuan-Jie , Auer Carol
Published: September 2019

Camelina sativa (camelina) is an oilseed crop in the Brassicaceae that has been genetically engineered for the production of biofuels, dietary supplements, and other industrial compounds. Cultivation in North America is both recent and limited, so there are gaps in knowledge regarding yield, weed competition, and pollen-mediated gene flow. For these experiments, camelina ‘SO-40’ was grown for three years without weed control. Spring-sown camelina was harvested at 80-88 days with ∼1200 growing degree days (GDD) with yields of 425-508 kg/hectare. Camelina yields were the same with or without weeds, showing competitive ability in low-management conditions. Crop failure in 2015 was associated with delayed rainfall and above-average temperatures after seeding. Camelina flowers attracted pollinating insects from the Hymenoptera, Diptera, Lepidoptera, and Coleoptera. Hymenoptera included honey bees (Apis melifera), mining bees (Andrenidae), sweat bees (Halictidae), bumble bees (Bombus spp.) and leaf cutter bees (Megachilidae). Insect visitation on camelina flowers was associated with modest increases in seed yield. Honey bees comprised 28-33% of all pollinators and were shown to carry camelina pollen on their legs. Air sampling showed that wind-blown pollen was present at low concentrations at 9 m beyond the edges of the field. These experiments demonstrated for the first time that camelina pollen dispersal could occur through honey bees or wind, although bee activity would likely be more significant for long-distance gene flow.
Spontaneous oligomerization of BAK/BAX is suppressed by hetero-dimerization with MCL-1
Authors: Wicky Basile I. M. , Gupta Kallol , Kwan Tristan O. C. , Robinson Carol V. , Clarke Jane
Published: September 2019

BCL-2 proteins control the intrinsic pathway of programmed cell death. Composed of anti- and pro-apoptotic members, their network of interactions forms a molecular switch that controls mitochondrial outer-membrane permeability. Apoptotic stimulation leads to BAK/BAX oligomerization and pore formation, yet the molecular details of this pivotal step remain poorly understood, and controversy persists regarding the activation mechanism. Here we use native mass spectrometry and kinetics to show that the homo-oligomerization of BAK and BAX is spontaneous in hydrophobic environments. This process is abrogated by hetero-dimerization of both BAK and BAX with the anti-apoptotic BCL-2 protein MCL-1. Pro-apoptotic BH3-only proteins disrupt these hetero-dimers by binding competitively to MCL-1, releasing BAK/BAX for homo-oligomerization. Thus, we infer that their oligomeric states are thermodynamically favored at the membrane. Our approach provides the framework for future quantitative biophysical characterizations of the BCL-2 network, and advances our molecular understanding of apoptosis.
A signalling axis involving CNOT3, Aurora B and ERK promotes differentiation and survival of mesendodermal progenitor cells
Authors: Sarkar Moumita , Martufi Matteo , Roman-Trufero Monica , Wang Yi-Fang , Whilding Chad , Dormann Dirk , Sabbattini Pierangela , Dillon Niall
Published: September 2019

Mesendoderm cells are key intermediate progenitors that form at the early primitive streak (PrS) and give rise to mesoderm and endoderm in the gastrulating embryo. We have identified an interaction between CNOT3 and the cell cycle kinase Aurora B, which requires sequences in the NOT box domain of CNOT3, and regulates MAPK/ERK signalling during mesendoderm differentiation. Aurora B phosphorylates CNOT3 at two sites located close to a nuclear localization signal and promotes localization of CNOT3 to the nuclei of mouse ES cells (ESCs) and metastatic lung cancer cells. ESCs that have both sites mutated give rise to embryoid bodies that are largely devoid of mesoderm and endoderm and are composed mainly of ectoderm. The mutant ESCs are also compromised in their ability to differentiate into mesendoderm in response to FGF2, BMP4 and Wnt3. The double mutation affects interaction of CNOT3 with Aurora B and with ERK and reduces phosphorylation of ERK in response to FGF2, impacting on survival of the differentiated ME cells. Our results identify an adaptor function for CNOT3 that regulates a key pathway in embryogenesis and cancer.
Long range channelrhodopsin-assisted circuit mapping of inferior colliculus neurons with blue and red-shifted channelrhodopsins
Authors: Goyer David , Roberts Michael T.
Published: September 2019

When investigating neural circuits, a standard limitation of the in vitro patch clamp approach is that axons from multiple sources are often intermixed, making it difficult to isolate inputs from individual sources with electrical stimulation. However, by using channelrhodopsin assisted circuit mapping (CRACM) this limitation can now be overcome. Here, we report a method to use CRACM to map ascending inputs from lower auditory brainstem nuclei and commissural inputs to an identified class of neurons in the inferior colliculus (IC), the midbrain nucleus of the auditory system. In the IC, local, commissural, ascending, and descending axons are heavily intertwined and therefore indistinguishable with electrical stimulation. By injecting a viral construct to drive expression of a channelrhodopsin in a presynaptic nucleus, followed by patch clamp recording to characterize the presence and physiology of channelrhodopsin-expressing synaptic inputs, projections from a specific source to a specific population of IC neurons can be mapped with cell type-specific accuracy. We show that this approach works with both Chronos, a blue light-activated channelrhodopsin, and ChrimsonR, a red-shifted channelrhodopsin. In contrast to previous reports from the forebrain, we find that ChrimsonR is robustly trafficked down the axons of dorsal cochlear nucleus principal neurons, indicating that ChrimsonR may be a useful tool for CRACM experiments in the brainstem. The protocol presented here includes detailed descriptions of the intracranial virus injection surgery, including stereotaxic coordinates for targeting injections to the dorsal cochlear nucleus and IC of mice, and how to combine whole cell patch clamp recording with channelrhodopsin activation to investigate long-range projections to IC neurons. Although this protocol is tailored to characterizing auditory inputs to the IC, it can be easily adapted to investigate other long-range projections in the auditory brainstem and beyond.

Channelrhodopsin-assisted circuit mapping (CRACM) is a precision technique for functional mapping of long-range neuronal projections between anatomically and/or genetically identified groups of neurons. Here, we describe how to utilize CRACM to map auditory brainstem connections, including the use of a red-shifted opsin, ChrimsonR.
Context-dependent decision making in a premotor circuit
Authors: Wu Zheng , Litwin-Kumar Ashok , Shamash Philip , Taylor Alexei , Axel Richard , Shadlen Michael N.
Published: September 2019

Cognitive capacities afford contingent associations between sensory information and behavioral responses. We studied this problem using an olfactory delayed match to sample task whereby a sample odor specifies the association between a subsequent test odor and rewarding action. Multi-neuron recordings revealed representations of the sample and test odors in olfactory sensory and association cortex, which were sufficient to identify the test odor as match/non-match. Yet, inactivation of a downstream premotor area (ALM), but not orbitofrontal cortex, confined to the epoch preceding the test odor, led to gross impairment. Olfactory decisions that were not context dependent were unimpaired. Therefore, ALM may not receive the outcome of a match/non-match decision from upstream areas but contextual information—the identity of the sample—to establish the mapping between test odor and action. A novel population of pyramidal neurons in ALM layer 2 may mediate this process.
Agrobacterium-mediated floral-dip transformation of the obligate outcrosser Capsella grandiflora
Authors: Dew-Budd Kelly , David Brandon , Beilstein Mark A.
Published: September 2019

Plant transformation by floral dip has been essential for research on plant genetics. The plant family Brassicaceae is one of the most well studied plant families and contains both established and emerging genetic model species. Two emerging model species that bear on the evolution of the selfing syndrome are Capsella grandiflora, an obligate outcrosser, and C. rubella, an inbreeder. While the selfing syndrome has been well characterized at the genomic level the genetic mechanisms underlying it remain elusive, in part due to the challenges of establishing mutation lines in C. grandiflora. Here, we describe an efficient method for transforming C. grandiflora by Agrobacterium-mediated floral-dip while simultaneously tracking self-incompatibility loci. With the ability to transform both C. grandiflora and C. rubella, researchers have gained a valuable tool to study the progression to selfing at the genetic level.
Octanol-water partition coefficient measurements for the SAMPL6 Blind Prediction Challenge
Authors: Işık Mehtap , Levorse Dorothy , Mobley David L. , Rhodes Timothy , Chodera John D.
Published: September 2019

Partition coefficients describe the equilibrium partitioning of a single, defined charge state of a solute between two liquid phases in contact, typically a neutral solute. Octanol-water partition coefficients (Kow), or their logarithms (logP), are frequently used as a measure of lipophilicity in drug discovery. The partition coefficient is a physicochemical property that captures the thermodynamics of relative solvation between aqueous and nonpolar phases, and therefore provides an excellent test for physics-based computational models that predict properties of pharmaceutical relevance such as protein-ligand binding affinities or hydration/solvation free energies. The SAMPL6 Part II Octanol-Water Partition Coefficient Prediction Challenge used a subset of kinase inhibitor fragment-like compounds from the SAMPL6 pKaPrediction Challenge in a blind experimental benchmark. Following experimental data collection, the partition coefficient dataset was kept blinded until all predictions were collected from participating computational chemistry groups. A total of 91 submissions were received from 27 participating research groups. This paper presents the octanol-water logPdataset for this SAMPL6 Part II Partition Coefficient Challenge, which consisted of 11 compounds (six 4-aminoquinazolines, two benzimidazole, one pyrazolo[3,4-d]pyrimidine, one pyridine, one 2-oxoquinoline substructure containing compounds) with logPvalues in the range of 1.95–4.09. We describe the potentiometric logPmeasurement protocol used to collect this dataset using a Sirius T3, discuss the limitations of this experimental approach, and share suggestions for future logPdata collection efforts for the evaluation of computational methods.
Millennials’ intention to stay and word-of-mouth referrals
Authors: Dechawatanapaisal Decha
Published: September 2019

Purpose

The purpose of this paper is to investigate the mediating effect of organizational identification in the relationship between person-organization fit and intention to stay as well as word-of-mouth referrals. The study also examines the role of perceived external prestige as a moderator of the relationship between organizational identification and intention to stay and word-of-mouth referrals.

Design/methodology/approach

Data were collected from 2,649 millennial employees working in various companies located within the Central Thailand Industrial Estates. The hypothesized relationships were tested and analyzed by means of a confirmatory factor analysis, structural equation modeling, hierarchical regression and a bootstrapping procedure.

Findings

The results revealed that the direct relationships between person-organization fit and intention to stay as well as word-of-mouth referrals were found to be partially mediated by organizational identification. In addition, perceived external prestige was found to have a moderating effect on the relationship between organizational identification and word-of-mouth referrals, but found no effect on employee retention.

Research limitations/implications

The current research took place among the millennial workers in Thai organizations, which needs to be extended to other generational cohorts or different culture settings for more generalization.

Practical implications

The results imply that managers should routinely assess and monitor person-organization compatibility, and ensure that corporate cultures, values and norms are properly communicated and mutually shared among the millennial workers. The aim is to inspire them to perceive better fits and proudly identify with their workplace. Such efforts are likely to induce not only retention, but also should encourage word-of-mouth referrals.

Originality/value

This study extends existing knowledge by assessing the relationships among person-organization fit, organizational identification and perceived external prestige as well as their impacts on intention to stay and word-of-mouth referrals by millennial employees, which has not been extensively investigated in the literature.
Trends and changes in the International Journal of Entrepreneurial Behaviour & Research
Authors: Duran-Sanchez Amador , Alvarez García José , Del Río-Rama María de la Cruz , Ratten Vanessa
Published: September 2019

Purpose

The International Journal of Entrepreneurial Behaviour & Research is amongst the most prestigious entrepreneurship journals and rapidly gaining ascendancy as a premier journal. It is a relatively young journal being 24 years old and in 2018 achieved inclusion on the Social Science Citation Index. The purpose of this paper is to analyse the development of the journal from birth to its current trends in order to project future potential research trends. This will enable an understanding of potential future research topics that will be influential in the entrepreneurship research field.

Design/methodology/approach

A bibliometric analysis is conducted using the Scopus database to analyse the most cited articles, authors, institutions, country of origin and topic of article. This analysis is done with the view to analysing the changes that have occurred and the topics that are emerging in the journal.

Findings

Whilst initially a journal focussed more on European entrepreneurship research, there has been an increased internationalisation of the topics and countries represented in the journal. In addition, initially the focus was more on small business but this has widened to include more diverse topics related to entrepreneurship such as learning.

Originality/value

As evident in the bibliometric analysis and growth of citations, this journal has published innovative and path breaking studies that impact other journals. Thus, it is important to analyse how the journal has grown and what the future holds.
Design, dynamic modelling and control of tilt-rotor UAVs: a review
Authors: Hegde Navya Thirumaleshwar , George V.I. , Nayak C. Gurudas , Kumar Kamlesh
Published: September 2019

Purpose

The purpose of this paper is to give reviews on the platform modeling and design of a controller for autonomous vertical take-off and landing (VTOL) tilt rotor hybrid unmanned aerial vehicles (UAVs). Nowadays, UAVs have experienced remarkable progress and can be classified into two main types, i.e. fixed-wing UAVs and VTOL UAVs. The mathematical model of tilt rotor UAV is time variant, multivariable and non-linear in nature. Solving and understanding these plant models is very complex. Developing a control algorithm to improve the performance and stability of a UAV is a challenging task.

Design/methodology/approach

This paper gives a thorough description on modeling of VTOL tilt rotor UAV from first principle theory. The review of the design of both linear and non-linear control algorithms are explained in detail. The robust flight controller for the six degrees of freedom UAV has been designed using H-infinity optimization with loop shaping under external wind and aerodynamic disturbances.

Findings

This review will act as a basis for the future work on modeling and control of VTOL tilt rotor UAV by the researchers. The development of self-guided and fully autonomous UAVs would result in reducing the risk to human life. Civil applications include inspection of rescue teams, terrain, coasts, border patrol buildings, police and pipelines. The simulation results show that the controller achieves robust stability, good adaptability and robust performance.

Originality/value

The review articles on quadrotors/quadcopters, hybrid UAVs can be found in many literature, but there are comparatively a lesser amount of review articles on the detailed description of VTOL Tilt rotor UAV. In this paper modeling, platform design and control algorithms for the tilt rotor are presented. A robust H-infinity loop shaping controller in the presence of disturbances is designed for VTOL UAV.
Lean manufacturing and productivity changes: the moderating role of R&D
Authors: Shi Yingjie , Wang Xinyu , Zhu Xuechang
Published: September 2019

Purpose

The purpose of this paper is to empirically investigate the effect of lean manufacturing on productivity changes and to identify the root sources of productivity changes. Furthermore, the authors explore the moderating effects of research and development (R&D) to examine the relationship between lean manufacturing and productivity changes.

Design/methodology/approach

This paper employs the propensity score matching (PSM) model combined with the difference-in-difference (DID) estimation to overcome the selectivity bias. The Malmquist productivity index is used to capture productivity changes. By analyzing 671 Chinese manufacturing listed firms from 2009 to 2014, the moderating effects of R&D on the relationship between lean manufacturing and productivity changes are measured.

Findings

The results reveal that lean manufacturing implementation has non-significant effects on productivity changes in principle, while a detailed analysis indicates that lean manufacturing could improve scale efficiency significantly. While engaged in R&D could significantly improve the efficiency of technological changes for lean manufacturing implementation firms, there exist negative effects on pure technical efficiency.

Research limitations/implications

This research only covers manufacturing listed firms in China. Further studies should extend the generalizability of the findings.

Practical implications

This study helps managers to identify the important role of R&D on the relationship between lean manufacturing and productivity changes and provides insights into how to improve the lean manufacturing performance.

Originality/value

This paper appears to be one of the earliest studies on the relationship between lean manufacturing and productivity changes by applying the PSM combined with DID estimation in Chinese manufacturing environment.
An empirical analysis of emoji usage on Twitter
Authors: Li Mengdi , Chng Eugene , Chong Alain Yee Loong , See Simon
Published: September 2019

Purpose

Emoji has become an essential component of any digital communication and its importance can be attested to by its sustained popularity and widespread use. However, research in Emojis is rarely to be seen due to the lack of data at a greater scale. The purpose of this paper is to systematically analyse and compare the usage of Emojis in a cross-cultural manner.

Design/methodology/approach

This research conducted an empirical analysis using a large-scale, cross-regional emoji usage data set from Twitter, a platform where the limited 140 characters allowance has made it essential for the inclusion of emojis within tweets. The extremely large textual data set covers a period of only two months, but the 673m tweets authored by more than 2,081,542 unique users is a sufficiently large sample for the authors to yield significant results.

Findings

This research discovered that the categories and frequencies of Emojis communicated by users can provide a rich source of data to understand cultural differences between Twitter users from a large range of demographics. This research subsequently demonstrated the preferential use of Emojis complies with Hofstede’s Cultural Dimensions Model, in which different representations of demographics and culture within countries present significantly different use of Emojis to communicate emotions.

Originality/value

This study provides a robust example of how to strategically conduct research using large-scale emoji data to pursue research questions previously difficult. To the best of authors’ knowledge, the present study pioneers the first systematic analysis and comparison of the usage of emojis on Twitter across different cultures; it is the largest, in terms of the scale study of emoji usage to-date.
The influence of ESG information on investment allocation decisions
Authors: Khemir Souhir , Baccouche Chedli , Ayadi Salma Damak
Published: September 2019

Purpose

In addition to financial reporting, more and more companies report environmental, social and governance (ESG) information in emerging countries. This practice is intended to fulfill the information needs of all the company’s stakeholders, and more specifically the investors. The purpose of this paper is twofold. First, to analyze whether investors include ESG information into their investment allocation decisions in Tunisian capital market. Second, to identify the information dimension having the more effect on their investment allocation decisions.

Design/methodology/approach

A field experiment was conducted in an emerging country (Tunisia) among 245 novices and experienced financial stakeholders to analyze how ESG information is taken into account in their investment allocation decisions.

Findings

The results of the factorial mixed analysis of variance show that ESG information influenced the investment allocation decisions in Tunisia. In addition, the results of thepost-hoctest indicate that governance and social information had more influence than environmental information.

Research limitations/implications

This paper is limited to the analysis of the influence of ESG information only on the decisions of financial stakeholders in Tunisia. In future research works, it will be relevant to study the decisions of other stakeholders and to carry out comparative studies between several countries.

Practical implications

The results can only strengthen and motivate companies to pay more attention to their ESG information disclosure practices. They are also likely to attract the attention of the accounting standard setters on the need to standardize these practices.

Originality/value

The original contribution of this paper lies not only in the analysis of three dimensions of extra-financial information: E, S and G through an experiment carried out in an emerging country, but also especially in the comparison of the influence of each dimension on investment allocation decisions.
Intensifying business success of Malaysian housing development firms through entrepreneurial learning
Authors: Syed Abu Bakar Syed Putra , Jaafar Mastura , Muhibudin Masitah
Published: September 2019

Purpose

The purpose of this paper is to investigate the impacts of entrepreneurial learning on the performance of Malaysian private housing developers. Although the extant literature on learning epistemology is quite voluminous, the focus within the housing entrepreneurship remains limited. With this lacuna, the investigation on the perceptions of learning propensity among residential developers is deemed timely.

Design/methodology/approach

Using snowball sampling, interviews were conducted with ten perceived successful private housing developers in Malaysia to understand the antecedents and consequences of entrepreneurial learning in steering their business toward excellence.

Findings

The research outcomes revealed that all the interviewed respondents concurred with the importance of entrepreneurial learning within the organization to strive for business success. The interviewed housing developers highlighted the significance of learning interest in their daily works to achieve business competitiveness and gain competitive edge against rivals. Through continuous learning, positive ideas and ethos could be instilled within the uncertain business environment.

Research limitations/implications

From an empirical standpoint, the sample was limited to private housing developers in one country. This limits the scope of generalization. Further studies, comparing between public and private developers in multiple contexts should be undertaken. Besides that, the research is based on a relatively small sample of ten respondents and the use of snowball sampling may have meant that the respondents would only tend to present a particular view of the industry.

Practical implications

The results raise interesting impacts on business success for scholars and entrepreneurs to ponder upon. The research contributes new knowledge about the effects of entrepreneurial learning toward the competitiveness of housing developers, by looking at the whole aspects of development process. A better understanding on how business knowledge could be retrieved from the perspectives of Malaysian housing developers is posited to be pragmatically employed.

Originality/value

Concomitantly with the above proposition, the study offers a novel insight into learning capabilities of Malaysian private housing developers that may be useful for global references. Understanding firm’s resources and capabilities is emergent that warrants further clarifications on entrepreneurial learning within housing development firms. The paper successfully illuminates comprehensive issues that have responded to this shortfall.