Solubilisation of biological lipid bilayer membranes for analysis of their protein complement has traditionally been carried out using detergents, but there is increasing interest in the use of amphiphilic copolymers such as styrene maleic acid (SMA) for the solubilisation, purification and characterisation of integral membrane proteins in the form of protein/lipid nanodiscs. Here we survey the effectiveness of various commercially-available formulations of the SMA copolymer in solubilising Rhodobacter sphaeroides reaction centres (RCs) from photosynthetic membranes. We find that formulations of SMA with a 2:1 or 3:1 ratio of styrene to maleic acid are almost as effective as detergent in solubilising RCs, with the best solubilisation by short chain variants (< 30 kDa weight average molecular weight). The effectiveness of 10 kDa 2:1 and 3:1 formulations of SMA to solubilise RCs gradually declined when genetically-encoded coiled-coil bundles were used to artificially tether normally monomeric RCs into dimeric, trimeric and tetrameric multimers. The ability of SMA to solubilise reaction centre-light harvesting 1 (RC-LH1) complexes from densely packed and highly ordered photosynthetic membranes was uniformly low, but could be increased through a variety of treatments to increase the lipid:protein ratio. However, proteins isolated from such membranes comprised clusters of complexes in small membrane patches rather than individual proteins. We conclude that short-chain 2:1 and 3:1 formulations of SMA are the most effective in solubilising integral membrane proteins, but that solubilisation efficiencies are strongly influenced by the size of the target protein and the density of packing of proteins in the membrane.
Candida species are the fourth most common cause of bloodstream infection (BSI) in the hospitalized patient. Candida glabrata is the most common non-Candida albicans Candida species in England and Wales with an attributed mortality of 48 %. C. glabrata is known to demonstrate reduced susceptibility to fluconazole, resulting in treatment failures when employing this agent for empirical treatment of Candida BSI. The first part of this study demonstrated a technique utilizing a blood culture system commonly used by many laboratories (BACTEC 9240 automated detection system) that reduced the time to identification of this potentially resistant organism by up to 72 h. A presumptive identification was achieved by observing a difference in the duration of incubation required before growth was detected automatically between Lytic Anaerobic and Plus Aerobic culture bottles. Secondly, experiments exploring the growth characteristics of C. glabrata in BACTEC blood culture bottles containing various media were carried out to explore possible reasons underpinning this clinical observation. The detection of yeast in the anaerobic bottle of a blood culture pair consisting of Lytic Anaerobic and Plus Aerobic in a BACTEC 9240 system was found to be highly predictive of the isolation of C. glabrata (positive predictive value 93.3 %, negative predictive value 98.3 %). The reason for this appeared to be a component of the Lytic Anaerobic blood culture medium enhancing the growth of C. glabrata in that medium.
Music has been identified as a strength in people with Autism Spectrum Disorder, however, there is currently no neuroscientific evidence supporting its benefits. Given its universal appeal, intrinsic reward value and ability to modify brain and behaviour, music may be a potential therapeutic aid in autism. Here, we evaluated the neurobehavioral outcomes of a music intervention, compared to a non-music control intervention, on social communication and brain connectivity in school-age children (ISRCTN26821793). Fifty-one 6-12 year olds with autism were randomized to receive 8-12 weeks of music (n=26) or non-music intervention (n=25). The music intervention involved use of improvisational approaches through song and rhythm to target social communication. The non-music control was a structurally-matched behavioural intervention implemented in a non-musical context. Groups were assessed before and after intervention on social communication and resting-state functional connectivity of fronto-temporal brain networks. Communication scores were higher in the music group post-intervention (difference score=4.84, P=.01). Associated post-intervention resting-state brain functional connectivity was greater in music versus non-music groups between auditory and subcortical regions (z=3.94, P<.0001) and auditory and fronto-motor regions (z=3.16, P<.0001). Post-intervention brain connectivity was lower between auditory and visual regions in music compared to non-music groups, known to be over-connected in autism (z=4.01, P<.00001). Post-intervention brain connectivity in the music group was related to communication improvement (z=3.57, P<.0001). This study provides the first evidence that 8-12 weeks of individual music intervention can indeed improve social communication and functional brain connectivity, lending support to further investigations of neurobiologically-motivated models of music interventions in autism.
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