Tetrameric structure of beta-amylase 2 (BAM2) in Arabidopsis thaliana

Plants store starch during the day for use at night. This process of transitory starch degradation is mostly attributable to the β-Amylase (BAM) family, which are starch exohydrolases that cleave the penultimate α-1,4 glycosidic bonds of starch to release maltose. BAM2 was recently characterized as a catalytically active, K+-requiring tetramer with sigmoidal kinetics and cooperativity. All other catalytically active BAMs display Michaelis-Menten kinetics, no cooperativity, and do not require salt, making BAM2’s characteristics intriguing. Due to a lack of a crystal structure, a monomeric homology model of BAM2 was generated using I-TASSER based on a BAM5 from soybean. The monomer model was then used to make a tetramer model based on the homotetrameric crystal structure of sweet potato BAM5 with YASARA. The tetramer model was tested through site directed mutagenesis of conserved residues that were hypothesized to form interfaces between subunits. Two residues, D490 and W456, are perfectly conserved and located in one interface of the tetramer model. Residue F238 is a perfectly conserved residue that would be in another interface of the tetramer model if the model were slightly shifted and more compact. Site directed mutagenesis was used to swap these residues with a different amino acid, and the mutant proteins were purified for use in enzyme activity assays and size analysis by Size Exclusion Chromatography-Multi Angle Light Scattering. BAM2 D490R and BAM2 W456A disrupted tetramerization and catalytic activity. The F238A mutant is dimeric and maintains catalytic activity resembling BAM2 WT, but with a higher Km. The results of these mutagenesis experiments revealed that activity of BAM2, unlike other active BAMs, is dependent on its quaternary structure and that the starch-binding groove must be held together with residues in interface A for BAM2 to be active

Parent Perspectives of an Occupational Therapy Telehealth Intervention

Occupational therapy services delivered via telehealth can support families of young children with autism spectrum disorders (ASD) in everyday routines such as mealtime, bedtime, and play. The aim of the current study was to understand the lived experiences of parents who participated in a 12-week, telehealth-delivered occupational therapy intervention (Occupation-Based Coaching). We used semi-structured interviews and subsequent thematic content analysis to understand how parents perceived the mechanism of service delivery (i.e., videoconferencing) and the content of the intervention. Themes that emerged from the data included Compatibility with Everyday Life, Collaborative Relationship, and Parent Empowerment. Parents expressed how telehealth fit within their daily lives, how telehealth supported a collaborative relationship with the occupational therapist, and how the content of the intervention built a sense of empowerment

Does Experimental Anterior Knee Pain Alter Effects of Running on Femoral Articular Cartilage Thickness and Volume? A Pilot Study

Anterior knee pain is a common problem for runners that often alters running biomechanics. It is unclear how/if changes in running biomechanics due to anterior knee pain affect knee articular cartilage health. PURPOSE: To determine if experimental anterior knee pain during running acutely alters deformation in femoral articular cartilage due to running. METHODS: 10 runners completed three sessions that each in- volved a 60-min treadmill run: a control, sham, and pain session. Experimental anterior knee pain was in- duced during the pain session via a continuous infusion of hypertonic saline into the infrapatellar fat pad. The sham and control sessions involved a continuous infusion of physiological saline and no infusion, re- spectively. Before and after running, magnetic resonance imaging was used to quantify femoral articular cartilage thickness and volume. A repeated measures ANOVA was used to evaluate effects of running with experimental anterior knee pain on perceived knee pain and femoral articular cartilage deformation (α = 0.05). RESULTS: Perceived anterior knee pain was significantly greater during the pain session relative to the control and sham sessions (p p = 0.05), and more due to the pain session run (-57.7 ± 157.4 mm3) than the control session run (p = 0.09). No significant effects of session were observed for medial or lateral thickness or lateral volume. CONCLUSION: Articular cartilage response to running (medial femoral volume) was different for the pain and sham sessions relative to the control session. The physiological and hypertonic saline infusions appeared to alter medial knee articular cartilage response to running. These changes might be due to altered biomechanics due to the infusions. Additional research is needed to clarify the cause of the altered response to running

GC-149 - S\u27eyed\u27Kick: AI Powered Reading Assistant and Translator

According to the Centers for Disease Control (CDC), roughly 12 million people in the United States above the age of 40 are visually impaired. In adults 18 years and older, visual impairment is one of the top 10 disabilities. It can have an enormous effect on one’s independence and quality of life. Assistive technology through artificial intelligence (AI) can support the visually impaired in everyday life functions. Our application is specifically designed for reading text such as small print. After the user selects the language for translation out of 34 choices and takes a picture of the text with the app, the text is extracted from the image. The text is converted to speech and played to the user in audio format. The text is also enlarged and displayed on the screen. Overall, this app is a benefit to society through increasing the quality of life for the visually impaired

Polysaccharide degradation by the Bacteroidetes: mechanisms and nomenclature

The Bacteroidetes phylum is renowned for its ability to degrade a wide range of complex carbohydrates, a trait that has enabled its dominance in many diverse environments. The best studied species inhabit the human gut microbiome and use polysaccharide utilization loci (PULs), discrete genetic structures that encode proteins involved in the sensing, binding, deconstruction, and import of target glycans. In many environmental species, polysaccharide degradation is tightly coupled to the phylum-exclusive type IX secretion system (T9SS), which is used for the secretion of certain enzymes and is linked to gliding motility. In addition, within specific species these two adaptive systems (PULs and T9SS) are intertwined, with PUL-encoded enzymes being secreted by the T9SS. Here, we discuss the most noteworthy PUL and non-PUL mechanisms that confer specific and rapid polysaccharide degradation capabilities to the Bacteroidetes in a range of environments. We also acknowledge that the literature showcasing examples of PULs is rapidly expanding and developing a set of assumptions that can be hard to track back to original findings. Therefore, we present a simple universal description of conserved PUL functions and how they are determined, while proposing a common nomenclature describing PULs and their components, to simplify discussion and understanding of PUL systems

A future workforce of food-system analysts

A programme developed across five UK universities aims to equip graduate professionals with the skills, tools and capabilities to better understand and manage food-system complexity for food security, for the environment and for enterprise.<br/

Single cell transcriptome profiling of developing chick retinal cells

The vertebrate retina is a specialized photosensitive tissue comprised of six neuronal and one glial cell types, each of which develops in prescribed proportions at overlapping timepoints from a common progenitor pool. While each of these cells has a specific function contributing to proper vision in the mature animal, their differential representation in the retina as well as the presence of distinctive cellular subtypes makes identifying the transcriptomic signatures that lead to each retinal cell’s fate determination and development challenging. We have analyzed transcriptomes from individual cells isolated from the chick retina throughout retinogenesis. While we focused our efforts on the retinal ganglion cells, our transcriptomes of developing chick cells also contained representation from multiple retinal cell types, including photoreceptors and interneurons at different stages of development. Most interesting was the identification of transcriptomes from individual mixed lineage progenitor cells in the chick as these cells offer a window into the cell fate decision-making process. Taken together, these datasets will enable us to uncover the most critical genes acting in the steps of cell fate determination and early differentiation of various retinal cell types

Elevation change, mass balance, dynamics and surging of Langjökull, Iceland from 1997 to 2007

ABSTRACTGlaciers and ice caps around the world are changing quickly, with surge-type behaviour superimposed upon climatic forcing. Here, we study Iceland's second largest ice cap, Langjökull, which has both surge- and non-surge-type outlets. By differencing elevation change with surface mass balance, we estimate the contribution of ice dynamics to elevation change. We use DEMs, in situ stake measurements, regional reanalyses and a mass-balance model to calculate the vertical ice velocity. Thus, we not only compare the geodetic, modelled and glaciological mass balances, but also map spatial variations in glacier dynamics. Maps of emergence and submergence velocity successfully highlight the 1998 surge and subsequent quiescence of one of Langjökull's outlets by visualizing both source and sink areas. In addition to observing the extent of traditional surge behaviour (i.e. mass transfer from the accumulation area to the ablation area followed by recharge of the source area), we see peripheral areas where the surge impinged upon an adjacent ridge and subsequently retreated. While mass balances are largely in good agreement, discrepancies between modelled and geodetic mass balance may be explained by inaccurate estimates of precipitation, saturated adiabatic lapse rate or degree-day factors. Nevertheless, the study was ultimately able to investigate dynamic surge behaviour in the absence of in situ measurements during the surge.In situ mass balance survey is a joint effort of the Glaciology Group, Institute of Earth Sciences, University of Iceland and the National Power Company (Landsvirkjun). We thank Philippe Crochet and Tómas Jóhannesson from the Icelandic Meteorological Office for providing the gridded climate data and for useful discussions about the climatology of Langjökull. The 2007 lidar data were collected by the UK Natural Environment Research Council Airborne Research and Survey Facility (Grant IPY 07-08). Additional funding was provided by the United States National Science Foundation (Grant No. DGE-1038596), St Catharine’s, St John’s and Trinity Colleges and the University of Cambridge B.B. Roberts and Scandinavian Studies Funds. We thank Cameron Rye for initial help coding the mass balance model.This is the author accepted manuscript. The final version is available from Cambridge University Press via https://doi.org/10.1017/jog.2016.5