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931.
932.
Ze Qin Lim Qing Yong Ng Yukei Oo Justin Jang Hann Chu Shi Yan Ng Siu Kwan Sze Sylvie Alonso 《EMBO reports》2021,22(6)
Enterovirus‐A71 (EV‐A71) has been associated with severe neurological forms of hand, foot, and mouth disease (HFMD). EV‐A71 infects motor neurons at neuromuscular junctions (NMJs) to invade the central nervous system (CNS). Here, we investigate the role of peripherin (PRPH) during EV‐A71 infection, a type III intermediate neurofilament involved in neurodegenerative conditions. In mice infected with EV‐A71, PRPH co‐localizes with viral particles in the muscles at NMJs and in the spinal cord. In motor neuron‐like and neuroblastoma cell lines, surface‐expressed PRPH facilitates viral entry, while intracellular PRPH influences viral genome replication through interactions with structural and non‐structural viral components. Importantly, PRPH does not play a role during infection with coxsackievirus A16, another causative agent of HFMD rarely associated with neurological complications, suggesting that EV‐A71 ability to exploit PRPH represents a unique attribute for successful CNS invasion. Finally, we show that EV‐A71 also exploits some of the many PRPH‐interacting partners. Of these, small GTP‐binding protein Rac1 represents a potential druggable host target to limit neuroinvasion of EV‐A71. 相似文献
933.
Gordon Y. C. Cheung Justin S. Bae Ryan Liu Rachelle L. Hunt Yue Zheng Michael Otto 《PLoS pathogens》2021,17(2)
Bacterial sepsis is a major global cause of death. However, the pathophysiology of sepsis has remained poorly understood. In industrialized nations, Staphylococcus aureus represents the pathogen most commonly associated with mortality due to sepsis. Because of the alarming spread of antibiotic resistance, anti-virulence strategies are often proposed to treat staphylococcal sepsis. However, we do not yet completely understand if and how bacterial virulence contributes to sepsis, which is vital for a thorough assessment of such strategies. We here examined the role of virulence and quorum-sensing regulation in mouse and rabbit models of sepsis caused by methicillin-resistant S. aureus (MRSA). We determined that leukopenia was a predictor of disease outcome during an early critical stage of sepsis. Furthermore, in device-associated infection as the most frequent type of staphylococcal blood infection, quorum-sensing deficiency resulted in significantly higher mortality. Our findings give important guidance regarding anti-virulence drug development strategies for the treatment of staphylococcal sepsis. Moreover, they considerably add to our understanding of how bacterial sepsis develops by revealing a critical early stage of infection during which the battle between bacteria and leukocytes determines sepsis outcome. While sepsis has traditionally been attributed mainly to host factors, our study highlights a key role of the invading pathogen and its virulence mechanisms. 相似文献
934.
Environmental factors inherent to animal facilities can impact on the neuro-behavioural phenotype of laboratory mice and genetic mouse models for human diseases. Many facilities have upgraded from traditional ‘open filter top’ cages (FT) to individually ventilated cage (IVC) systems, which have been shown to modify various behavioural responses of laboratory mice. Importantly, the impact of IVC housing on the G93A superoxide dismutase 1 mouse model of amyotrophic lateral sclerosis (ALS) is currently unknown. Male and female wild type-like (WT) and heterozygous SOD1G93A mice were group-housed in FT or IVC systems from PND 30 ± 5 onwards. Body weight and motor function were assessed weekly from 15 weeks onward. Mice were also tested for cognitive abilities (i.e., fear conditioning and social recognition memory) and sensorimotor gating (i.e., prepulse inhibition: PPI). SOD1G93A mice lost body weight, and their motor function degenerated over time compared with control littermates. Motor impairments developed faster when SOD1G93A females were housed in IVCs. Context and cue freezing were increased in SOD1G93A females compared with controls, whereas all SOD1G93A mice exhibited lower acoustic startle and PPI than WT mice. IVC housing led to an increase in cue freezing in males and reduced the severity of PPI deficits in SOD1G93A females. Overall, IVC housing impacted moderately on the SOD1G93A phenotype but central behavioural deficits were still evident across housing conditions. Nonetheless, our findings indicate the importance of assessing the effect of cage system in genetic mouse models as these systems can modulate the magnitude and onset of genotypic differences. 相似文献
935.
Paula E. Oliveira Dong Chen Brianne E. Bell Thomas I. Harris Caleb Walker Haixia Zhang Brittany Grob Randolph V. Lewis Justin A. Jones 《Microbial biotechnology》2021,14(5):1976-1989
Native hagfish intermediate filament proteins have impressive mechanical properties. However, using these native fibres for any application is impractical, necessitating their recombinant production. In the only literature report on the proteins (denoted α and ɣ), heterologous expression levels, using E. coli, were low and no attempts were made to optimize expression, explore wet-spinning, or spin the two proteins individually into fibres. Reported here is the high production (~8 g l−1 of dry protein) of the hagfish intermediate filament proteins, with yields orders of magnitude higher (325–1000×) than previous reports. The proteins were spun into fibres individually and in their native-like 1:1 ratio. For all fibres, the hallmark α-helix to β-sheet conversion occurred after draw-processing. The native-like 1:1 ratio fibres achieved the highest average tensile strength in this study at nearly 200 MPa with an elastic modulus of 5.7 GPa, representing the highest tensile strength reported for these proteins without chemical cross-linking. Interestingly, the recombinant α protein achieved nearly the same mechanical properties when spun as a homopolymeric fibre. These results suggest that varying the two protein ratios beyond the natural 1:1 ratio will allow a high degree of tunability. With robust heterologous expression and purification established, optimizing fibre spinning will be accelerated compared to difficult to produce proteins such as spider silks. 相似文献
936.
Justin T. Fisher Travis O. Gurney Brittany M. Mason Jay K. Fisher William J. Kelly 《Biotechnology journal》2021,16(5):2000257
Bioprocess optimization for cell-based therapies is a resource heavy activity. To reduce the associated cost and time, process development may be carried out in small volume systems, with the caveat that such systems be predictive for process scale-up. The transport of oxygen from the gas phase into the culture medium, characterized using the volumetric mass transfer coefficient, kLa, has been identified as a critical parameter for predictive process scale-up. Here, we describe the development of a 96-well microplate with integrated Redbud Posts to provide mixing and enhanced kLa. Mixing in the microplate is characterized by observation of dyes and analyzed using the relative mixing index (RMI). The kLa is measured via dynamic gassing out method. Actuating Redbud Posts are shown to increase rate of planar homogeneity (2 min) verse diffusion alone (120 min) and increase oxygenation, with increasing stirrer speed (3500-9000 rpm) and decreasing fill volume (150-350 μL) leading to an increase in kLa (4-88 h−1). Significant increase in Chinese Hamster Ovary growth in Redbud Labs vessel (580,000 cells mL-1) versus the control (420,000 cells mL-1); t(12.814) = 8.3678, p ≤ .001), and CD4+ Naïve cell growth in the microbioreactor indicates the potential for this technology in early stage bioprocess development and optimization. 相似文献
937.
Victoria I. Austin Anastasia H. Dalziell Naomi E. Langmore Justin A. Welbergen 《Biological reviews of the Cambridge Philosophical Society》2021,96(4):1484-1503
Research on avian vocalisations has traditionally focused on male song produced by oscine passerines. However, accumulating evidence indicates that complex vocalisations can readily evolve outside the traditional contexts of mate attraction and territory defence by male birds, and yet the previous bias towards male song has shaped – and continues to shape – our understanding of avian communication as a whole. Accordingly, in this review we seek to address this imbalance by synthesising studies on female vocalisations from across signalling contexts throughout the Aves, and discuss the implications of recent empirical advances for our understanding of vocalisations in both sexes. This review reveals great structural and functional diversity among female vocalisations and highlights the important roles that vocalisations can play in mediating female-specific behaviours. However, fundamental gaps remain. While there are now several case studies that identify the function of female vocalisations, few quantify the associated fitness benefits. Additionally, very little is known about the role of vocal learning in the development of female vocalisations. Thus, there remains a pressing need to examine the function and development of all forms of vocalisations in female birds. In the light of what we now know about the functions and mechanisms of female vocalisations, we suggest that conventional male-biased definitions of songs and calls are inadequate for furthering our understanding of avian vocal communication more generally. Therefore, we propose two simple alternatives, both emancipated from the sex of the singer. The first distinguishes song from calls functionally as a sexually selected vocal signal, whilst the second distinguishes them mechanistically in terms of their underlying neurological processes. It is clear that more investigations are needed into the ultimate and proximate causes of female vocalisations; however, these are essential if we are to develop a holistic epistemology of avian vocal communication in both sexes, across ecological contexts and taxonomic divides. 相似文献
938.
Steffen Mumme Arthur D. Middleton Paolo Ciucci Johannes De Groeve Andrea Corradini Ellen O. Aikens Federico Ossi Paul Atwood Niko Balkenhol Eric K. Cole Lucie Debeffe Sarah R. Dewey Claude Fischer Justin Gude Marco Heurich Mark A. Hurley Anders Jarnemo Matthew J. Kauffman Alain Licoppe Emiel van Loon Doug McWhirter Tony W. Mong Luca Pedrotti Nicolas Morellet Atle Mysterud Wibke Peters Kelly Proffitt Sonia Saïd Johannes Signer Peter Sunde Martin Starý Francesca Cagnacci 《Global Change Biology》2023,29(20):5788-5801
Human activity and associated landscape modifications alter the movements of animals with consequences for populations and ecosystems worldwide. Species performing long-distance movements are thought to be particularly sensitive to human impact. Despite the increasing anthropogenic pressure, it remains challenging to understand and predict animals' responses to human activity. Here we address this knowledge gap using 1206 Global Positioning System movement trajectories of 815 individuals from 14 red deer (Cervus elaphus) and 14 elk (Cervus canadensis) populations spanning wide environmental gradients, namely the latitudinal range from the Alps to Scandinavia in Europe, and the Greater Yellowstone Ecosystem in North America. We measured individual-level movements relative to the environmental context, or movement expression, using the standardized metric Intensity of Use, reflecting both the directionality and extent of movements. We expected movement expression to be affected by resource (Normalized Difference Vegetation Index, NDVI) predictability and topography, but those factors to be superseded by human impact. Red deer and elk movement expression varied along a continuum, from highly segmented trajectories over relatively small areas (high intensity of use), to directed transitions through restricted corridors (low intensity of use). Human activity (Human Footprint Index, HFI) was the strongest driver of movement expression, with a steep increase in Intensity of Use as HFI increased, but only until a threshold was reached. After exceeding this level of impact, the Intensity of Use remained unchanged. These results indicate the overall sensitivity of Cervus movement expression to human activity and suggest a limitation of plastic responses under high human pressure, despite the species also occurring in human-dominated landscapes. Our work represents the first comparison of metric-based movement expression across widely distributed populations of a deer genus, contributing to the understanding and prediction of animals' responses to human activity. 相似文献
939.
940.
Justin A. G. Hubbard D. Andrew R. Drake Nicholas E. Mandrak 《Diversity & distributions》2023,29(8):986-996