197 research outputs found
Habitus emerging : the development of hybrid logics and collaborative business models in the Irish craft beer sector
This article analyses data from 25 Irish craft beer entrepreneurs supplemented by associated web and press material, to explore how habitus emerges in a nascent entrepreneurial field. Welter's frame of entrepreneurial contexts – business, social, spatial, and institutional – is combined with Bourdieusian theory to explain the emergence of habitus. Findings show that emerging habitus is enacted through hybridization of diverse global and local field logics, via the adoption, development and extension of their logics. It is also path-dependent upon the life and career histories of a critical mass of habitus members, previously exposed to these fields. The study shows both local and global strategies of collective resource sharing - a novel approach to tackling the resource paucity typically faced by partitioned specialists facing large scale generalists
Inhibitor binding mode and allosteric regulation of Na+-glucose symporters.
Sodium-dependent glucose transporters (SGLTs) exploit sodium gradients to transport sugars across the plasma membrane. Due to their role in renal sugar reabsorption, SGLTs are targets for the treatment of type 2 diabetes. Current therapeutics are phlorizin derivatives that contain a sugar moiety bound to an aromatic aglycon tail. Here, we develop structural models of human SGLT1/2 in complex with inhibitors by combining computational and functional studies. Inhibitors bind with the sugar moiety in the sugar pocket and the aglycon tail in the extracellular vestibule. The binding poses corroborate mutagenesis studies and suggest a partial closure of the outer gate upon binding. The models also reveal a putative Na+ binding site in hSGLT1 whose disruption reduces the transport stoichiometry to the value observed in hSGLT2 and increases inhibition by aglycon tails. Our work demonstrates that subtype selectivity arises from Na+-regulated outer gate closure and a variable region in extracellular loop EL5
Conformational transitions of the sodium-dependent sugar transporter, vSGLT.
Sodium-dependent transporters couple the flow of Na+ ions down their electrochemical potential gradient to the uphill transport of various ligands. Many of these transporters share a common core structure composed of a five-helix inverted repeat and deliver their cargo utilizing an alternating-access mechanism. A detailed characterization of inward-facing conformations of the Na+-dependent sugar transporter from Vibrio parahaemolyticus (vSGLT) has previously been reported, but structural details on additional conformations and on how Na+ and ligand influence the equilibrium between other states remains unknown. Here, double electron-electron resonance spectroscopy, structural modeling, and molecular dynamics are utilized to deduce ligand-dependent equilibria shifts of vSGLT in micelles. In the absence and presence of saturating amounts of Na+, vSGLT favors an inward-facing conformation. Upon binding both Na+ and sugar, the equilibrium shifts toward either an outward-facing or occluded conformation. While Na+ alone does not stabilize the outward-facing state, gating charge calculations together with a kinetic model of transport suggest that the resting negative membrane potential of the cell, absent in detergent-solubilized samples, may stabilize vSGLT in an outward-open conformation where it is poised for binding external sugars. In total, these findings provide insights into ligand-induced conformational selection and delineate the transport cycle of vSGLT
Substrate-bound outward-open structure of a Na+-coupled sialic acid symporter reveals a new Na+ site
Many pathogenic bacteria utilise sialic acids as an energy source or use them as an external coating to evade immune detection. As such, bacteria that colonise sialylated environments deploy specific transporters to mediate import of scavenged sialic acids. Here, we report a substrate-bound 1.95 Å resolution structure and subsequent characterisation of SiaT, a sialic acid transporter from Proteus mirabilis. SiaT is a secondary active transporter of the sodium solute symporter (SSS) family, which use Na+ gradients to drive the uptake of extracellular substrates. SiaT adopts the LeuT-fold and is in an outward-open conformation in complex with the sialic acid N-acetylneuraminic acid and two Na+ ions. One Na+ binds to the conserved Na2 site, while the second Na+ binds to a new position, termed Na3, which is conserved in many SSS family members. Functional and molecular dynamics studies validate the substrate-binding site and demonstrate that both Na+ sites regulate N-acetylneuraminic acid transport
The effects of orange juice clarification on the physiology of Escherichia coli; growth-based and flow cytometric analysis
Orange juice (OJ) is a food product available in various forms which can be processed to a greater or lesser extent. Minimally-processed OJ has a high consumer perception but presents a potential microbiological risk due to acid-tolerant bacteria. Clarification of OJ (such as removal of cloud) is a common processing step in many OJ products. However, many of the antimicrobial components of OJ such as essential oils are present in the cloud fraction. Here, the effect of clarification by filtration on the viability and physiology of Escherichia coli K-12 was tested using total viable count (TVC) and flow cytometric (FCM) analysis. The latter technique was also used to monitor intracellular pH during incubation in OJ. Removal of the OJ cloud fraction was shown to have dramatic effects on bacterial viability and physiology during storage at a range of incubation temperatures. For instance, at 4°C, a significantly lower number of healthy cells and a significantly higher number of injured cells were observed in 0.22μm-filtered OJ at 24h post-inoculation, compared to filtered OJ samples containing particles between 0.22μm and 11μm in size. Similarly, there was a significant difference between the number of healthy bacteria in the 0.7μm-filtered OJ and both 0.22μm-filtered and 1.2μm-filtered OJ after 24hour incubation at 22.5°C. This indicated that OJ cloud between 0.7μm and 0.22μm in size might have an adverse effect on the viability of E. coli K-12. Furthermore, FCM allowed the rapid analysis of bacterial physiology without the requirement for growth on agar plates, and revealed the extent of the viable but non-culturable (VBNC) population. For example, at 4°C, while the FCM viable count did not substantially decrease until 48h, decreases in TVC were observed between 0 and 48hour incubation, due to a subset of injured bacteria entering the VBNC state, hence being unable to grow on agar plates. This study highlights the application of FCM in monitoring bacterial physiology in foods, and potential effects of OJ clarification on bacterial physiology
Effect of ethnomedicinal plants used in folklore medicine in Jordan as antibiotic resistant inhibitors on Escherichia coli
<p>Abstract</p> <p>Background</p> <p><it>Escherichia coli </it>occurs naturally in the human gut; however, certain strains that can cause infections, are becoming resistant to antibiotics. Multidrug-resistant <it>E. coli </it>that produce extended-spectrum β lactamases (ESBLs), such as the CTX-M enzymes, have emerged within the community setting as an important cause of urinary tract infections (UTIs) and bloodstream infections may be associated with these community-onsets. This is the first report testing the antibiotic resistance-modifying activity of nineteen Jordanian plants against multidrug-resistant <it>E. coli</it>.</p> <p>Methods</p> <p>The susceptibility of bacterial isolates to antibiotics was tested by determining their minimum inhibitory concentrations (MICs) using a broth microdilution method. Nineteen Jordanian plant extracts (<it>Capparis spinosa </it>L., <it>Artemisia herba-alba Asso, Echinops polyceras </it>Boiss., <it>Gundelia tournefortii </it>L, <it>Varthemia iphionoides </it>Boiss. & Blanche, <it>Eruca sativa Mill</it>., <it>Euphorbia macroclada </it>L., <it>Hypericum trequetrifolium </it>Turra, <it>Achillea santolina </it>L., <it>Mentha longifolia </it>Host, <it>Origanum syriacum </it>L., <it>Phlomis brachydo</it>(Boiss.) Zohary, <it>Teucrium polium </it>L., <it>Anagyris foetida </it>L., <it>Trigonella foenum-graecum </it>L., <it>Thea sinensis </it>L., <it>Hibiscus sabdariffa </it>L., <it>Lepidium sativum </it>L., <it>Pimpinella anisum </it>L.) were combined with antibiotics, from different classes, and the inhibitory effect of the combinations was estimated.</p> <p>Results</p> <p>Methanolic extracts of the plant materials enhanced the inhibitory effects of chloramphenicol, neomycin, doxycycline, cephalexin and nalidixic acid against both the standard strain and to a lesser extent the resistant strain of <it>E. coli</it>. Two edible plant extracts (<it>Gundelia tournefortii L</it>. and <it>Pimpinella anisum L</it>.) generally enhanced activity against resistant strain. Some of the plant extracts like <it>Origanum syriacum </it>L.(Labiateae), <it>Trigonella foenum- graecum </it>L.(Leguminosae), <it>Euphorbia macroclada </it>(Euphorbiaceae) and <it>Hibiscus sabdariffa </it>(Malvaceae) did not enhance the activity of amoxicillin against both standard and resistant <it>E. coli</it>. On the other hand combinations of amoxicillin with other plant extracts used showed variable effect between standard and resistant strains. Plant extracts like <it>Anagyris foetida </it>(Leguminosae) and <it>Lepidium sativum </it>(Umbelliferae) reduced the activity of amoxicillin against the standard strain but enhanced the activity against resistant strains. Three edible plants; Gundelia <it>tournefortii </it>L. (Compositae) <it>Eruca sativa </it>Mill. (Cruciferae), and <it>Origanum syriacum </it>L. (Labiateae), enhanced activity of clarithromycin against the resistant <it>E. coli </it>strain.</p> <p>Conclusion</p> <p>This study probably suggests possibility of concurrent use of these antibiotics and plant extracts in treating infections caused by <it>E. coli </it>or at least the concomitant administration may not impair the antimicrobial activity of these antibiotics.</p
Global and Regional Differences in Brain Anatomy of Young Children Born Small for Gestational Age
In children who are born small for gestational age (SGA), an adverse intrauterine environment has led to underdevelopment of both the body and the brain. The delay in body growth is (partially) restored during the first two years in a majority of these children. In addition to a negative influence on these physical parameters, decreased levels of intelligence and cognitive impairments have been described in children born SGA. In this study, we used magnetic resonance imaging to examine brain anatomy in 4- to 7-year-old SGA children with and without complete bodily catch-up growth and compared them to healthy children born appropriate for gestational age. Our findings demonstrate that these children strongly differ on brain organisation when compared with healthy controls relating to both global and regional anatomical differences. Children born SGA displayed reduced cerebral and cerebellar grey and white matter volumes, smaller volumes of subcortical structures and reduced cortical surface area. Regional differences in prefrontal cortical thickness suggest a different development of the cerebral cortex. SGA children with bodily catch-up growth constitute an intermediate between those children without catch-up growth and healthy controls. Therefore, bodily catch-up growth in children born SGA does not implicate full catch-up growth of the brain
Global, regional, and national burden of stroke and its risk factors, 1990-2019: a systematic analysis for the Global Burden of Disease Study 2019
Background: Regularly updated data on stroke and its pathological types, including data on their incidence, prevalence, mortality, disability, risk factors, and epidemiological trends, are important for evidence-based stroke care planning and resource allocation. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) aims to provide a standardised and comprehensive measurement of these metrics at global, regional, and national levels. Methods: We applied GBD 2019 analytical tools to calculate stroke incidence, prevalence, mortality, disability-adjusted life-years (DALYs), and the population attributable fraction (PAF) of DALYs (with corresponding 95% uncertainty intervals [UIs]) associated with 19 risk factors, for 204 countries and territories from 1990 to 2019. These estimates were provided for ischaemic stroke, intracerebral haemorrhage, subarachnoid haemorrhage, and all strokes combined, and stratified by sex, age group, and World Bank country income level. Findings: In 2019, there were 12·2 million (95% UI 11·0–13·6) incident cases of stroke, 101 million (93·2–111) prevalent cases of stroke, 143 million (133–153) DALYs due to stroke, and 6·55 million (6·00–7·02) deaths from stroke. Globally, stroke remained the second-leading cause of death (11·6% [10·8–12·2] of total deaths) and the third-leading cause of death and disability combined (5·7% [5·1–6·2] of total DALYs) in 2019. From 1990 to 2019, the absolute number of incident strokes increased by 70·0% (67·0–73·0), prevalent strokes increased by 85·0% (83·0–88·0), deaths from stroke increased by 43·0% (31·0–55·0), and DALYs due to stroke increased by 32·0% (22·0–42·0). During the same period, age-standardised rates of stroke incidence decreased by 17·0% (15·0–18·0), mortality decreased by 36·0% (31·0–42·0), prevalence decreased by 6·0% (5·0–7·0), and DALYs decreased by 36·0% (31·0–42·0). However, among people younger than 70 years, prevalence rates increased by 22·0% (21·0–24·0) and incidence rates increased by 15·0% (12·0–18·0). In 2019, the age-standardised stroke-related mortality rate was 3·6 (3·5–3·8) times higher in the World Bank low-income group than in the World Bank high-income group, and the age-standardised stroke-related DALY rate was 3·7 (3·5–3·9) times higher in the low-income group than the high-income group. Ischaemic stroke constituted 62·4% of all incident strokes in 2019 (7·63 million [6·57–8·96]), while intracerebral haemorrhage constituted 27·9% (3·41 million [2·97–3·91]) and subarachnoid haemorrhage constituted 9·7% (1·18 million [1·01–1·39]). In 2019, the five leading risk factors for stroke were high systolic blood pressure (contributing to 79·6 million [67·7–90·8] DALYs or 55·5% [48·2–62·0] of total stroke DALYs), high body-mass index (34·9 million [22·3–48·6] DALYs or 24·3% [15·7–33·2]), high fasting plasma glucose (28·9 million [19·8–41·5] DALYs or 20·2% [13·8–29·1]), ambient particulate matter pollution (28·7 million [23·4–33·4] DALYs or 20·1% [16·6–23·0]), and smoking (25·3 million [22·6–28·2] DALYs or 17·6% [16·4–19·0]). Interpretation: The annual number of strokes and deaths due to stroke increased substantially from 1990 to 2019, despite substantial reductions in age-standardised rates, particularly among people older than 70 years. The highest age-standardised stroke-related mortality and DALY rates were in the World Bank low-income group. The fastest-growing risk factor for stroke between 1990 and 2019 was high body-mass index. Without urgent implementation of effective primary prevention strategies, the stroke burden will probably continue to grow across the world, particularly in low-income countries.Valery L. Feigin … Andrew T Olagunju … Lalit Yadav … et al. (The 2019 Stroke Collaborators
Global, regional, and national burden of stroke and its risk factors, 1990-2019 : a systematic analysis for the Global Burden of Disease Study 2019
Background Regularly updated data on stroke and its pathological types, including data on their incidence, prevalence, mortality, disability, risk factors, and epidemiological trends, are important for evidence-based stroke care planning and resource allocation. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) aims to provide a standardised and comprehensive measurement of these metrics at global, regional, and national levels.
Methods We applied GBD 2019 analytical tools to calculate stroke incidence, prevalence, mortality, disability-adjusted life-years (DALYs), and the population attributable fraction (PAF) of DALYs (with corresponding 95% uncertainty intervals [UIs]) associated with 19 risk factors, for 204 countries and territories from 1990 to 2019. These estimates were provided for ischaemic stroke, intracerebral haemorrhage, subarachnoid haemorrhage, and all strokes
combined, and stratified by sex, age group, and World Bank country income level.
Findings In 2019, there were 12·2 million (95% UI 11·0–13·6) incident cases of stroke, 101 million (93·2–111) prevalent cases of stroke, 143 million (133–153) DALYs due to stroke, and 6·55 million (6·00–7·02) deaths from stroke. Globally, stroke remained the second-leading cause of death (11·6% [10·8–12·2] of total deaths) and the third-leading cause of death and disability combined (5·7% [5·1–6·2] of total DALYs) in 2019. From 1990 to 2019, the
absolute number of incident strokes increased by 70·0% (67·0–73·0), prevalent strokes increased by 85·0% (83·0–88·0), deaths from stroke increased by 43·0% (31·0–55·0), and DALYs due to stroke increased by 32·0% (22·0–42·0). During the same period, age-standardised rates of stroke incidence decreased by 17·0% (15·0–18·0), mortality decreased by 36·0% (31·0–42·0), prevalence decreased by 6·0% (5·0–7·0), and DALYs decreased by 36·0% (31·0–42·0). However, among people younger than 70 years, prevalence rates increased by 22·0% (21·0–24·0)
and incidence rates increased by 15·0% (12·0–18·0). In 2019, the age-standardised stroke-related mortality rate was 3·6 (3·5–3·8) times higher in the World Bank low-income group than in the World Bank high-income group, and
the age-standardised stroke-related DALY rate was 3·7 (3·5–3·9) times higher in the low-income group than the high-income group. Ischaemic stroke constituted 62·4% of all incident strokes in 2019 (7·63 million [6·57–8·96]), while intracerebral haemorrhage constituted 27·9% (3·41 million [2·97–3·91]) and subarachnoid haemorrhage constituted 9·7% (1·18 million [1·01–1·39]). In 2019, the five leading risk factors for stroke were high systolic blood pressure (contributing to 79·6 million [67·7–90·8] DALYs or 55·5% [48·2–62·0] of total stroke DALYs), high bodymass index (34·9 million [22·3–48·6] DALYs or 24·3% [15·7–33·2]), high fasting plasma glucose (28·9 million [19·8–41·5] DALYs or 20·2% [13·8–29·1]), ambient particulate matter pollution (28·7 million [23·4–33·4] DALYs or 20·1% [16·6–23·0]), and smoking (25·3 million [22·6–28·2] DALYs or 17·6% [16·4–19·0]). Interpretation The annual number of strokes and deaths due to stroke increased substantially from 1990 to 2019, despite substantial reductions in age-standardised rates, particularly among people older than 70 years. The highest age-standardised stroke-related mortality and DALY rates were in the World Bank low-income group. The fastest growing risk factor for stroke between 1990 and 2019 was high body-mass index. Without urgent implementation of
effective primary prevention strategies, the stroke burden will probably continue to grow across the world, particularly in low-income countries
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