Structural and mutational characterization of the catalytic A-module of the mannuronan C-5-epimerase AlgE4 from Azotobacter vinelandii

Alginate is a family of linear copolymers of (1→4)-linked β-d-mannuronic acid and its C-5 epimer α-l-guluronic acid. The polymer is first produced as polymannuronic acid and the guluronic acid residues are then introduced at the polymer level by mannuronan C-5-epimerases. The structure of the catalytic A-module of the Azotobacter vinelandii mannuronan C-5-epimerase AlgE4 has been determined by x-ray crystallography at 2.1-Å resolution. AlgE4A folds into a right-handed parallel β-helix structure originally found in pectate lyase C and subsequently in several polysaccharide lyases and hydrolases. The β-helix is composed of four parallel β-sheets, comprising 12 complete turns, and has an amphipathic α-helix near the N terminus. The catalytic site is positioned in a positively charged cleft formed by loops extending from the surface encompassing Asp(152), an amino acid previously shown to be important for the reaction. Site-directed mutagenesis further implicates Tyr(149), His(154), and Asp(178) as being essential for activity. Tyr(149) probably acts as the proton acceptor, whereas His(154) is the proton donor in the epimerization reaction

Aging affects the phase coherence between spontaneous oscillations in brain oxygenation and neural activity

The risk of neurodegenerative disorders increases with age, due to reduced vascular nutrition and impaired neural function. However, the interactions between cardiovascular dynamics and neural activity, and how these interactions evolve in healthy aging, are not well understood. Here, the interactions are studied by assessment of the phase coherence between spontaneous oscillations in cerebral oxygenation measured by fNIRS, the electrical activity of the brain measured by EEG, and cardiovascular functions extracted from ECG and respiration effort, all simultaneously recorded. Signals measured at rest in 21 younger participants (31.1±6.9 years) and 24 older participants (64.9±6.9 years) were analysed by wavelet transform, wavelet phase coherence and ridge extraction for frequencies between 0.007 and 4 Hz. Coherence between the neural and oxygenation oscillations at ∼0.1 Hz is significantly reduced in the older adults in 46/176 fNIRSEEG probe combinations. This reduction in coherence cannot be accounted for in terms of reduced power, thus indicating that neurovascular interactions change with age. The approach presented promises a noninvasive means of evaluating the efficiency of the neurovascular unit in aging and disease

Sonication is superior to scraping for retrieval of bacteria in biofilm on titanium and steel surfaces in vitro

Background and purpose Low-virulence implant infections are characterized by bacterial colonization of the implant with subsequent biofilm formation. In these cases, soft tissue biopsies often prove to be culture negative. Consequently, detachment of the causative adherent bacteria is crucial for correct microbiological diagnosis. Using an in vitro model, we compared 4 methods of biofilm sampling from metal surfaces

Genome-Wide Transcript Profiling of Endosperm without Paternal Contribution Identifies Parent-of-Origin–Dependent Regulation of AGAMOUS-LIKE36

Seed development in angiosperms is dependent on the interplay among different transcriptional programs operating in the embryo, the endosperm, and the maternally-derived seed coat. In angiosperms, the embryo and the endosperm are products of double fertilization during which the two pollen sperm cells fuse with the egg cell and the central cell of the female gametophyte. In Arabidopsis, analyses of mutants in the cell-cycle regulator CYCLIN DEPENDENT KINASE A;1 (CKDA;1) have revealed the importance of a paternal genome for the effective development of the endosperm and ultimately the seed. Here we have exploited cdka;1 fertilization as a novel tool for the identification of seed regulators and factors involved in parent-of-origin–specific regulation during seed development. We have generated genome-wide transcription profiles of cdka;1 fertilized seeds and identified approximately 600 genes that are downregulated in the absence of a paternal genome. Among those, AGAMOUS-LIKE (AGL) genes encoding Type-I MADS-box transcription factors were significantly overrepresented. Here, AGL36 was chosen for an in-depth study and shown to be imprinted. We demonstrate that AGL36 parent-of-origin–dependent expression is controlled by the activity of METHYLTRANSFERASE1 (MET1) maintenance DNA methyltransferase and DEMETER (DME) DNA glycosylase. Interestingly, our data also show that the active maternal allele of AGL36 is regulated throughout endosperm development by components of the FIS Polycomb Repressive Complex 2 (PRC2), revealing a new type of dual epigenetic regulation in seeds

Web-based collaboration in individual care planning challenges the user and the provider roles – toward a power transition in caring relationships

Jorunn Bjerkan,1,2 Solfrid Vatne,3 Anne Hollingen4 1Norwegian Research Centre for Electronic Health Records (EHR), Medical Faculty, Norwegian University of Science and Technology, Trondheim, 2Faculty of Health Science, Nord-Trøndelag University College, Levanger, 3Faculty of Health Science, Molde University College, 4Møre og Romsdal Hospital Trust, Molde, Norway Background and objective: The Individual Care Plan (ICP) was introduced in Norway to meet new statutory requirements for user participation in health care planning, incorporating multidisciplinary and cross-sector collaboration. A web-based solution (electronic ICP [e-ICP]) was used to support the planning and documentation. The aim of this study was to investigate how web-based collaboration challenged user and professional roles. Methods: Data were obtained from 15 semistructured interviews with users and eight with care professionals, and from two focus-group interviews with eight care professionals in total. The data were analyzed using systematic text condensation in a stepwise analysis model. Results: Users and care professionals took either a proactive or a reluctant role in e-ICP collaboration. Where both user and care professionals were proactive, the pairing helped to ensure that the planning worked well; so did pairings of proactive care professionals and reluctant users. Proactive users paired with reluctant care professionals also made care planning work, thanks to the availability of information and the users' own capacity or willingness to conduct the planning. Where both parties were reluctant, no planning activities occurred. Conclusion: Use of the e-ICP challenged the user–professional relationship. In some cases, a power transition took place in the care process, which led to patient empowerment. This knowledge might be used to develop a new understanding of how role function can be challenged when users and care professionals have equal access to health care documentation and planning tools. Keywords: integrated care, patient participation, empowerment, role transition, system testing, web-based collaboration, Norwa

Demonstrating Active Distribution Grids and Active Demand 

Active distribution grids and active customers require a rethinking of ICT tools and architectures in order to connect systems, platforms and actors previously unable to exchange information across domains of the energy business. This paper presents results from an R&D project focusing on developing a reference architecture for an open smart grid middleware, able to cope with the wide range of services necessary to integrate both DSOs, retailers and consumers as well as new actors (such as aggregators and prosumers) to a common framework. Such a framework is necessary to develop, scale and design future energy-related services to customers and other relevant stakeholders in the energy system operation

The phase coherence of the neurovascular unit is reduced in Huntington’s disease

Acknowledgements: We would like to thank all patients and control participants for their participation—without them, this study would not have been possible. We are grateful to Franci Benko, research nurse at the Department of Neurology, University Medical Centre Ljubljana, for his invaluable help in organizing and carrying out the measurements. We also thank Fajko Bajrović for his support with the clinical part of the study and Boštjan Dolenc for the automated analysis which was used for initial checks. J.B. would like to thank Trevor Crawford, Benediktas Valys, Joe Rowland Adams and Charlie Mpetha for helpful discussions and Sam McCormack for guidance with programming. The High-End Computing facility at Lancaster University was used for data analysis. Figure 1 and the graphical abstract were created using BioRender.com.Funder: Sir John Fisher Foundation; DOI: https://doi.org/10.13039/100011314Abstract Huntington’s disease is a neurodegenerative disorder in which neuronal death leads to chorea and cognitive decline. Individuals with ≥40 cytosine–adenine–guanine repeats on the interesting transcript 15 gene develop Huntington’s disease due to a mutated huntingtin protein. While the associated structural and molecular changes are well characterized, the alterations in neurovascular function that lead to the symptoms are not yet fully understood. Recently, the neurovascular unit has gained attention as a key player in neurodegenerative diseases. The mutant huntingtin protein is known to be present in the major parts of the neurovascular unit in individuals with Huntington’s disease. However, a non-invasive assessment of neurovascular unit function in Huntington’s disease has not yet been performed. Here, we investigate neurovascular interactions in presymptomatic (N = 13) and symptomatic (N = 15) Huntington’s disease participants compared to healthy controls (N = 36). To assess the dynamics of oxygen transport to the brain, functional near-infrared spectroscopy, ECG and respiration effort were recorded. Simultaneously, neuronal activity was assessed using EEG. The resultant time series were analysed using methods for discerning time-resolved multiscale dynamics, such as wavelet transform power and wavelet phase coherence. Neurovascular phase coherence in the interval around 0.1 Hz is significantly reduced in both Huntington’s disease groups. The presymptomatic Huntington’s disease group has a lower power of oxygenation oscillations compared to controls. The spatial coherence of the oxygenation oscillations is lower in the symptomatic Huntington’s disease group compared to the controls. The EEG phase coherence, especially in the α band, is reduced in both Huntington’s disease groups and, to a significantly greater extent, in the symptomatic group. Our results show a reduced efficiency of the neurovascular unit in Huntington’s disease both in the presymptomatic and symptomatic stages of the disease. The vasculature is already significantly impaired in the presymptomatic stage of the disease, resulting in reduced cerebral blood flow control. The results indicate vascular remodelling, which is most likely a compensatory mechanism. In contrast, the declines in α and γ coherence indicate a gradual deterioration of neuronal activity. The results raise the question of whether functional changes in the vasculature precede the functional changes in neuronal activity, which requires further investigation. The observation of altered dynamics paves the way for a simple method to monitor the progression of Huntington’s disease non-invasively and evaluate the efficacy of treatments.</jats:p