A Case Study of Eukaryogenesis: The Evolution of Photoreception by Photolyase/Cryptochrome Proteins.

Eukaryogenesis, the origin of the eukaryotes, is still poorly understood. Herein, we show how a detailed all-kingdom phylogenetic analysis overlaid with a map of key biochemical features can provide valuable clues. The photolyase/cryptochrome family of proteins are well known to repair DNA in response to potentially harmful effects of sunlight and to entrain circadian rhythms. Phylogenetic analysis of photolyase/cryptochrome protein sequences from a wide range of prokaryotes and eukaryotes points to a number of horizontal gene transfer events between ancestral bacteria and ancestral eukaryotes. Previous experimental research has characterised patterns of tryptophan residues in these proteins that are important for photoreception, specifically a tryptophan dyad, a canonical tryptophan triad, an alternative tryptophan triad, a tryptophan tetrad and an alternative tetrad. Our results suggest that the spread of the different triad and tetrad motifs across the kingdoms of life accompanied the putative horizontal gene transfers and is consistent with multiple bacterial contributions to eukaryogenesis.

Interactive Cognitive-Motor Step Training Improves Cognitive Risk Factors of Falling in Older Adults - A Randomized Controlled Trial.

PURPOSE: Interactive cognitive-motor training (ICMT) requires individuals to perform both gross motor movements and complex information processing. This study investigated the effectiveness of ICMT on cognitive functions associated with falls in older adults. METHODS: A single-blinded randomized controlled trial was conducted in community-dwelling older adults (N = 90, mean age 81.5±7) without major cognitive impairment. Participants in the intervention group (IG) played four stepping games that required them to divide attention, inhibit irrelevant stimuli, switch between tasks, rotate objects and make rapid decisions. The recommended minimum dose was three 20-minute sessions per week over a period of 16 weeks unsupervised at home. Participants in the control group (CG) received an evidence-based brochure on fall prevention. Measures of processing speed, attention/executive function (EF), visuo-spatial ability, concerns about falling and depression were assessed before and after the intervention. RESULTS: Eighty-one participants (90%) attended re-assessment. There were no improvements with respect to the Stroop Stepping Test (primary outcome) in the intervention group. Compared to the CG, the IG improved significantly in measures of processing speed, visuo-spatial ability and concern about falling. Significant interactions were observed for measures of EF and divided attention, indicating group differences varied for different levels of the covariate with larger improvements in IG participants with poorer baseline performance. The interaction for depression showed no change for the IG but an increase in the CG for those with low depressive symptoms at baseline. Additionally, low and high-adherer groups differed in their baseline performance and responded differently to the intervention. Compared to high adherers, low adherers improved more in processing speed and visual scanning while high-adherers improved more in tasks related to EF. CONCLUSIONS: This study shows that unsupervised stepping ICMT led to improvements in specific cognitive functions associated with falls in older people. Low adherers improved in less complex functions while high-adherers improved in EF. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12613000671763.

A Stroop Stepping Test (SST) using low-cost computer game technology discriminates between older fallers and non-fallers.

BACKGROUND: impaired stepping and reduced cognitive functioning have both been identified as fall-risk factors in older people. We developed a Stroop Stepping Test (SST) that combines stepping and response inhibition using low-cost computer game technology to provide a functional measure that reflects real-life behaviour and determined whether this test discriminates between older fallers and non-fallers. METHODS: a cross-sectional study, including 103-independent living cognitively intact older people (70-93 years), was conducted. Participants were assessed on the SST and other outcome measures associated with fall-risk. The SST presented arrows on a computer screen with words written within them. Participants were asked to step in the direction indicated by the word and ignore the arrow orientation. Participants also reported whether they had fallen or not in the past 12 months. RESULTS: twenty-eight percent of participants reported falling in the past year. SST mean time per trial [OR: 1.72 (95% confidence interval 1.02-2.91) and SST errors (OR: 1.53 (1.14-2.07)] were associated with falls. After adjusting for other fall-risk factors in a multivariate logistic regression analysis, each error made during SST increased the odds of falling by a factor 1.7 [OR: 1.65 (1.17-2.34)]. CONCLUSIONS: this study shows the SST-a low-cost video game device-is feasible for older people to undertake. The SST was able to distinguish fallers from non-fallers, providing a novel way to explore cognitive mechanisms for fall-risk in older people.

Step Training System: an ICT solution to measure and reduce fall risk in older adults.

Falls in older adults are a significant public heath issue with over 1/3 community-dwelling people aged 65 and over falling each year, many of them multiple times. We have developed and evaluated a set top box PC solution for delivering both fall risk assessment and fall risk reduction programs into the home. Preliminary field tests show that older adults engage with the system but that barriers to maintained use of the system do exist.

A randomized controlled pilot study of home-based step training in older people using videogame technology.

BACKGROUND: Stepping impairments are associated with physical and cognitive decline in older adults and increased fall risk. Exercise interventions can reduce fall risk, but adherence is often low. A new exergame involving step training may provide an enjoyable exercise alternative for preventing falls in older people. PURPOSE: To assess the feasibility and safety of unsupervised, home-based step pad training and determine the effectiveness of this intervention on stepping performance and associated fall risk in older people. DESIGN: Single-blinded two-arm randomized controlled trial comparing step pad training with control (no-intervention). SETTING/PARTICIPANTS: Thirty-seven older adults residing in independent-living units of a retirement village in Sydney, Australia. INTERVENTION: Intervention group (IG) participants were provided with a computerized step pad system connected to their TVs and played a step game as often as they liked (with a recommended dose of 2-3 sessions per week for 15-20 minutes each) for eight weeks. In addition, IG participants were asked to complete a choice stepping reaction time (CSRT) task once each week. MAIN OUTCOME MEASURES: CSRT, the Physiological Profile Assessment (PPA), neuropsychological and functional mobility measures were assessed at baseline and eight week follow-up. RESULTS: Thirty-two participants completed the study (86.5%). IG participants played a median 2.75 sessions/week and no adverse events were reported. Compared to the control group, the IG significantly improved their CSRT (F31,1 = 18.203, p<.001), PPA composite scores (F31,1 = 12.706, p = 0.001), as well as the postural sway (F31,1 = 4.226, p = 0.049) and contrast sensitivity (F31,1 = 4.415, p = 0.044) PPA sub-component scores. In addition, the IG improved significantly in their dual-task ability as assessed by a timed up and go test/verbal fluency task (F31,1 = 4.226, p = 0.049). CONCLUSIONS: Step pad training can be safely undertaken at home to improve physical and cognitive parameters of fall risk in older people without major cognitive and physical impairments. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12611001081909.