Connecting DNA Origami Structures Using the Biotin-Streptavidin Specific Binding

This work made use of the strong interaction between biotin and streptavidin to connect designed DNA origami structures. The caDNAno software was used to design a 6 layer 3D origami cross-like structure. Selected DNA strands at the engineered attachment sites on the DNA origami structure were biotinylated. After folding of the origami structures, the biotinylated strands stick out of the attachment sites. Purified samples of origami structures were then mixed with streptavidin and the mixture purified. After characterization, we see that attachment only occurs at the biotinylated sites. Agarose gel electrophoresis, UV-vis spectroscopy and TEM were used to characterize the structure.Key words: DNA Origami, Interaction, Biotin-Streptavidin, Nanomaterials, TEMAbbreviation: EDTA, Ethylenediaminetetraacetic acid; TEM, Transmission electron microscop

Urinary Lysosomal Enzyme Activities and Albuminuria in Ghanaian Patients with Type 2 Diabetes Mellitus.

Renal tubular lysosomal enzyme activities like alanine aminopeptidase (AAP) and N-acetyl-β-D-glucosaminidase (NAG) have been shown to increase in patients developing diabetic nephropathy and nephrosclerosis. This study aimed to determine the activities of N-acetyl-β-D-glucosaminidase and alanine aminopeptidase and albumin concentration in urine samples of patients with type 2 diabetes. One hundred and thirty (65 type 2 diabetic and 65 nondiabetic) subjects participated in this study. Blood samples were drawn for measurements of fasting blood glucose, albumin (Alb), lipids, and creatinine (Cr). Early morning spot urine samples were also collected for activities of alanine aminopeptidase (AAP), N-acetyl-β-D-glucosaminidase (NAG), and concentration of albumin (U-Alb) and creatinine (U-Cr). Both NAG/Cr and AAP/Cr were significantly increased in diabetic subjects compared to controls (p < 0.001). There was positive correlation between NAG/Cr and Alb/Cr (r = 0.49, p < 0.001) and between NAG/Cr and serum creatinine (r = 0.441, p < 0.001). A negative correlation was found between NAG/Cr and eGFR (r = -0.432, p < 0.05). 9.3% and 12% of diabetics with normoalbuminuria had elevated levels of AAP/Cr and NAG/Cr, respectively. We conclude that measuring the urinary enzymes activities (NAG/Cr and AAP/Cr) could be useful as a biomarker of early renal involvement in diabetic complications

Sharing the salt bowl: counterion identity drives N-alkyl resorcinarene affinity for pyrophosphate in water

N-Alkyl ammonium resorcinarene chloride receptors, NARX4, have been shown to act as high-sensitivity detectors of pyrophosphate (PPi), a biomarker of disease, in aqueous media through the chloride-to-PPi exchange [NAR(Cl)4 to NARPPi]. The nature of the anion of the macrocyclic NARX4 (X = Cl−, Br−, triflate OTf−) receptor greatly influences the PPi-affinity in aqueous media. The binding affinity for [NAR (Cl)4] is 3.61 × 105 M−1, while the NAR (Br)4 and NAR (OTf)4 show stronger binding of 5.30 × 105 M−1, and 6.10 × 105 M−1, respectively. The effects of upper rim ammonium cation, –N+H2R substituents (R = 3-hydroxypropyl, cyclohexyl, benzyl, or napththalen-1-ylmethyl), of the macrocyclic resorcinarene hosts have also been evaluated. The highest affinity was obtained using 3-hydroxypropyl groups due to the additional hydrogen bonds and the naphthyl upper-rim group that provides a larger hydrophobic surface area and favorable stacking interaction (i.e., π–π and CH–π). We note that two PPi molecules can bind to the more selective receptors through an additional interaction with the lower rim hydroxyls, making the resorcinarene a divalent binder. Comparing PPi with other phosphate anions (PO43−, AMP, ADP, and ATP) shows that the receptors are more selective for PPi due to the size and charge complementarity. Experimental (1H, 31P NMR, and isothermal titration calorimetry), and computational analyses support the reported trends for PPi selectivity even in highly competing aqueous media

Naphthalene-functionalized resorcinarene as selective, fluorescent self-quenching sensor for kynurenic acid†

Kynurenic acid is a by-product of tryptophan metabolism in humans, with abnormal levels indicative of disease. There is a need for water-soluble receptors that selectively bind kynurenic acid, allowing for detection and quantification. We report here the high-affinity binding of kynurenic acid in aqueous media to a resorcinarene salt receptor decorated with four flexible naphthalene groups at the upper rim. Experimental results from 1H NMR, isothermal titration calorimetry, and electronic absorption and fluorescence spectroscopies all support high-affinity binding and selectivity for kynurenic acid over tryptophan. The measured binding constant (K = 1.46 ± 0.21 × 105 M−1) is one order of magnitude larger than that observed with other resorcinarene receptors. The present host–guest system can be employed for sensory recognition of kynurenic acid. Computational studies reveal the key role of a series of cooperative attractive intra- and inter-molecular interactions contributing to an optimal binding process in this system

The observability of galaxy merger signatures in nearby gas-rich spirals

Galaxy mergers are crucial to understanding galaxy evolution, therefore we must determine their observational signatures to select them from large IFU galaxy samples such as MUSE and SAMI. We employ 24 high-resolution idealized hydrodynamical galaxy merger simulations based on the ‘Feedback In Realistic Environment’ (FIRE-2) model to determine the observability of mergers to various configurations and stages using synthetic images and velocity maps. Our mergers cover a range of orbital configurations at fixed 1:2.5 stellar mass ratio for two gas rich spirals at low redshift. Morphological and kinematic asymmetries are computed for synthetic images and velocity maps spanning each interaction. We divide the interaction sequence into three: (1) the pair phase; (2) the merging phase; and (3) the post-coalescence phase. We correctly identify mergers between first pericentre passage and 500 Myr after coalescence using kinematic asymmetry with 66 per cent completeness, depending upon merger phase and the field of view of the observation. We detect fewer mergers in the pair phase (40 per cent) and many more in the merging and post-coalescence phases (97 per cent). We find that merger detectability decreases with field of view, except in retrograde mergers, where centrally concentrated asymmetric kinematic features enhances their detectability. Using a cut-off derived from a combination of photometric and kinematic asymmetry, we increase these detections to 89 per cent overall, 79 per cent in pairs, and close to 100 per cent in the merging and post-coalescent phases. By using this combined asymmetry cut-off we mitigate some of the effects caused by smaller fields of view subtended by massively multiplexed integral field spectroscopy programmes

Global Research Priorities to Better Understand the Burden of Iatrogenic Harm in Primary Care: An International Delphi Exercise

There is a need to identify and reach agreement on key foci for patient safety research in primary care contexts and understand how these priorities differ between low-, middle-, and high-income settings. We conducted a modified Delphi exercise, which was distributed to an international panel of experts in patient safety and primary care. Family practice and pharmacy were considered the main contexts on which to focus attention in order to advance patient safety in primary care across all income categories. Other clinical contexts prioritised included community midwifery and nursing in low-income countries and care homes in high-income countries. The sources of patient safety incidents requiring further study across all economic settings that were identified were communication between health care professionals and with patients, teamwork within the health care team, laboratory and diagnostic imaging investigations, issues relating to data management, transitions between different care settings, and chart/patient record com- pleteness. This work lays the foundation for a range of research initiatives that aim to promote a more comprehensive appreciation of the burden of unsafe primary care, develop understanding of the main areas of risk, and identify interventions that can enhance the safety of primary care provision internationall

Adolescent self-harm in Ghana: a qualitative interview-based study of first-hand accounts

Background: Recent prevalence studies suggest that self-harm among adolescents in sub-Saharan Africa is as common as it is in high income countries. However, very few qualitative studies exploring first-person accounts of adolescent self-harm are available from sub-Saharan Africa. We sought to explore the experiences and first-person perspectives of Ghanaian adolescents reporting self-harm - for deeper reflections on the interpretive repertoires available in their cultural context for making sense of self-harm in adolescents. Methods: Guided by a semi-structured interview protocol, we interviewed one-to-one 36 adolescents (24 in-school adolescents and 12 street-connected adolescents) on their experiences of self-harm. We applied experiential thematic analysis to the data. Results: Adolescents’ description of the background to their self-harm identified powerlessness in the family context and unwanted adultification in the family as key factors leading up to self-harm among both in-school and street-connected adolescents. Adolescents’ explanatory accounts identified the contradictory role of adultification as a protective factor against self-harm among street-connected adolescents. Self-harm among in-school adolescents was identified as a means of “enactment of tabooed emotions and contestations”, as a “selfish act and social injury”, as “religious transgression”, while it was also seen as improving social relations. Conclusions: The first-person accounts of adolescents in this study implicate familial relational problems and interpersonal difficulties as proximally leading to self-harm in adolescents. Self-harm in adolescents is interpreted as an understandable response, and as a strong communicative signal in response to powerlessness and family relationship difficulties. These findings need to be taken into consideration in the planning of services in Ghana and are likely to be generalisable to many other countries in sub-Saharan Africa