205 research outputs found
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Production of ent-kaurene from lignocellulosic hydrolysate in Rhodosporidium toruloides.
BACKGROUND:Rhodosporidium toruloides has emerged as a promising host for the production of bioproducts from lignocellulose, in part due to its ability to grow on lignocellulosic feedstocks, tolerate growth inhibitors, and co-utilize sugars and lignin-derived monomers. Ent-kaurene derivatives have a diverse range of potential applications from therapeutics to novel resin-based materials. RESULTS:The Design, Build, Test, and Learn (DBTL) approach was employed to engineer production of the non-native diterpene ent-kaurene in R. toruloides. Following expression of kaurene synthase (KS) in R. toruloides in the first DBTL cycle, a key limitation appeared to be the availability of the diterpene precursor, geranylgeranyl diphosphate (GGPP). Further DBTL cycles were carried out to select an optimal GGPP synthase and to balance its expression with KS, requiring two of the strongest promoters in R. toruloides, ANT (adenine nucleotide translocase) and TEF1 (translational elongation factor 1) to drive expression of the KS from Gibberella fujikuroi and a mutant version of an FPP synthase from Gallus gallus that produces GGPP. Scale-up of cultivation in a 2 L bioreactor using a corn stover hydrolysate resulted in an ent-kaurene titer of 1.4 g/L. CONCLUSION:This study builds upon previous work demonstrating the potential of R. toruloides as a robust and versatile host for the production of both mono- and sesquiterpenes, and is the first demonstration of the production of a non-native diterpene in this organism
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Brief Report: Schema Consistent Misinformation Effects in Eyewitnesses with Autism Spectrum Disorder
A number of studies have demonstrated schema-related misinformation effects in typical individuals, but no research to date has examined this with witnesses with autism spectrum disorder (ASD), despite their impaired ability to generate core elements that define everyday events. After witnessing slides depicting a bank robbery, 16 adults with ASD and 16 matched comparison individuals were exposed to post-event misinformation that was either schema typical or atypical. Consistent with previous work, the comparison group went onto report more schema typical misinformation than atypical misinformation. However, so too did the ASD group, suggesting that individuals with ASD do have understanding of the causal links between events, persons and actions, an important finding from both theoretical and applied perspectives
Drawing to Remember: External Support of Older Adults’ Eyewitness Performance
Although healthy aging is accompanied by a general decline in memory functioning, environmental support at retrieval can improve older adults’ (+65 years) episodic remembering. Despite those over the age of 65years representing a growing proportion of the population, few environmental retrieval support methods have been empirically evaluated for use with older witnesses and victims of crime. Here, the efficacy of a novel retrieval technique, the Sketch Mental Reinstatement of Context, is compared with a standard Mental Reinstatement of Context and a no support control (Control). Fifty-one participants witnessed an unexpected live event, and 48 hours later were interviewed using one of three aforementioned techniques. In line with predictions emanating from cognitive theories of aging and the environmental support hypothesis, participants in the Sketch Mental Reinstatement of Context condition recalled significantly more correct information and fewer inaccurate items. The Sketch Mental Reinstatement of Context technique appears to scaffold memory retrieval in an age-appropriate manner during a post-event interview, possibly by encouraging more effortful retrieval and reducing dual-task load. As such, this procedure offers an effective alternative to current approaches, adding to the toolbox of techniques available to forensic and other interviewers
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Eyewitness Testimony in Autism Spectrum Disorder: A Review
Autism spectrum disorder (ASD) is estimated to affect around 1% of the population, and is characterised by impairments in social interaction, communication, and behavioural flexibility. A number of risk factors indicate that individuals with ASD may become victims or witnesses of crimes. In addition to their social and communication deficits, people with ASD also have very specific memory problems, which impacts on their abilities to recall eyewitnessed events. We begin this review with an overview of the memory difficulties that are experienced by individuals with ASD, before discussing the studies that have specifically examined eyewitness testimony in this group and the implications for investigative practice. Finally, we outline related areas that would be particularly fruitful for future research to explore
Production of ent-kaurene from lignocellulosic hydrolysate in Rhodosporidium toruloides
Background: Rhodosporidium toruloides has emerged as a promising host for the production of bioproducts from lignocellulose, in part due to its ability to grow on lignocellulosic feedstocks, tolerate growth inhibitors, and co-utilize sugars and lignin-derived monomers. Ent-kaurene derivatives have a diverse range of potential applications from therapeutics to novel resin-based materials. Results: The Design, Build, Test, and Learn (DBTL) approach was employed to engineer production of the non-native diterpene ent-kaurene in R. toruloides. Following expression of kaurene synthase (KS) in R. toruloides in the first DBTL cycle, a key limitation appeared to be the availability of the diterpene precursor, geranylgeranyl diphosphate (GGPP). Further DBTL cycles were carried out to select an optimal GGPP synthase and to balance its expression with KS, requiring two of the strongest promoters in R. toruloides, ANT (adenine nucleotide translocase) and TEF1 (translational elongation factor 1) to drive expression of the KS from Gibberella fujikuroi and a mutant version of an FPP synthase from Gallus gallus that produces GGPP. Scale-up of cultivation in a 2 L bioreactor using a corn stover hydrolysate resulted in an ent-kaurene titer of 1.4 g/L. Conclusion: This study builds upon previous work demonstrating the potential of R. toruloides as a robust and versatile host for the production of both mono- and sesquiterpenes, and is the first demonstration of the production of a non-native diterpene in this organism
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Binary vector copy number engineering improves Agrobacterium-mediated transformation
The copy number of a plasmid is linked to its functionality, yet there have been few attempts to optimize higher-copy-number mutants for use across diverse origins of replication in different hosts. We use a high-throughput growth-coupled selection assay and a directed evolution approach to rapidly identify origin of replication mutations that influence copy number and screen for mutants that improve Agrobacterium-mediated transformation (AMT) efficiency. By introducing these mutations into binary vectors within the plasmid backbone used for AMT, we observe improved transient transformation of Nicotiana benthamiana in four diverse tested origins (pVS1, RK2, pSa and BBR1). For the best-performing origin, pVS1, we isolate higher-copy-number variants that increase stable transformation efficiencies by 60-100% in Arabidopsis thaliana and 390% in the oleaginous yeast Rhodosporidium toruloides. Our work provides an easily deployable framework to generate plasmid copy number variants that will enable greater precision in prokaryotic genetic engineering, in addition to improving AMT efficiency
Engineering Rhodosporidium toruloides for production of 3-hydroxypropionic acid from lignocellulosic hydrolysate
Microbial production of valuable bioproducts is a promising route towards green and sustainable manufacturing. The oleaginous yeast, Rhodosporidium toruloides, has emerged as an attractive host for the production of biofuels and bioproducts from lignocellulosic hydrolysates. 3-hydroxypropionic acid (3HP) is an attractive platform molecule that can be used to produce a wide range of commodity chemicals. This study focuses on establishing and optimizing the production of 3HP in R. toruloides. As R. toruloides naturally has a high metabolic flux towards malonyl-CoA, we exploited this pathway to produce 3HP. Upon finding the yeast capable of catabolizing 3HP, we then implemented functional genomics and metabolomic analysis to identify the catabolic pathways. Deletion of a putative malonate semialdehyde dehydrogenase gene encoding an oxidative 3HP pathway was found to significantly reduce 3HP degradation. We further explored monocarboxylate transporters to promote 3HP transport and identified a novel 3HP transporter in Aspergillus pseudoterreus by RNA-seq and proteomics. Combining these engineering efforts with media optimization in a fed-batch fermentation resulted in 45.4 g/L 3HP production. This represents one of the highest 3HP titers reported in yeast from lignocellulosic feedstocks. This work establishes R. toruloides as a host for 3HP production from lignocellulosic hydrolysate at high titers, and paves the way for further strain and process optimization towards enabling industrial production of 3HP in the future
The Use of Flight Progress Strips While Working Live Traffic: Frequencies, Importance, and Perceived Benefits
The Federal Aviation Administration's effort to automate air traffic control (ATC) requires that the functionality provided today be captured in future systems. We report the first quantitative naturalistic observation of paper flight progress strip interactions during operational use. Strip use was similar in a variety of situations, but some uses varied as a function of altitude, staffing, or the cooperative style used by controller teams. Design of automation should proceed by prioritizing changes based on frequency of use and importance and should ensure that an effective method of interacting with flight information is incorporated. In addition to applied relevance to the ATC domain, the results touch on several theoretical concerns relevant to dynamic environments. Actual and potential applications of this research include the establishment of a database of strip activity and an arsenal of information valuable to system designers.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline
Longitudinal assessment of cognitive and psychosocial functioning after Hurricanes Katrina and Rita: Exploring disaster impact on middle-aged, older, and oldest-old adults
The authors examined the effects of Hurricanes Katrina and Rita on cognitive and psychosocial functioning in a lifespan sample of adults 6-14 months after the storms. Participants were recruited from the Louisiana Healthy Aging Study. Most were assessed during the immediate impact period and retested for this study. Analyses of pre- and post-disaster cognitive data confirmed that storm-related decrements in working memory for middle-aged and older adults observed in the immediate impact period had returned to pre-hurricane levels in the post-disaster recovery period. Middle-aged adults reported more storm-related stressors and greater levels of stress than the two older groups at both waves of testing. These results are consistent with a burden perspective on post-disaster psychological reactions. © 2012 Wiley Periodicals, Inc
Processing of Self versus Non-Self in Alzheimer’s Disease
Despite considerable evidence for abnormalities of self-awareness in Alzheimer’s disease (AD), the cognitive mechanisms of altered self-processing in AD have not been fully defined. Here we addressed this issue in a detailed analysis of self/non-self-processing in three patients with AD. We designed a novel neuropsychological battery comprising tests of tactile body schema coding, attribution of tactile events to self versus external agents, and memory for self- versus non-self-generated vocal information, administered in conjunction with a daily life measure of self/non-self-processing (the Interpersonal Reactivity Index). Three male AD patients (aged 54–68 years; one with a pathogenic mutation in the Presenilin 1 gene, one with a pathogenic mutation in the Amyloid Precursor Protein gene, and one with a CSF protein profile supporting underlying AD pathology) were studied in relation to a group of eight healthy older male individuals (aged 58–74 years). Compared to healthy controls, all patients had relatively intact tactile body schema processing. In contrast, all patients showed impaired memory for words previously presented using the patient’s own voice whereas memory for words presented in other voices was less consistently affected. Two patients showed increased levels of emotional contagion and reduced perspective taking on the Interpersonal Reactivity Index. Our findings suggest that AD may be associated with deficient self/non-self differentiation over time despite a relatively intact body image: this profile of altered self-processing contrasts with the deficit of tactile body schema previously described in frontotemporal dementia associated with C9orf72 mutations. We present these findings as a preliminary rationale to direct future systematic study in larger patient cohorts
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