The formation of α-(1[right-facing arrow]3) D-glucosidic linkages by exocellular α-D-glucansucrases from Leuconostoc mesenteroides and Streptococcus mutans

Alternansucrase, an exocellular glucansucrase from Leuconostoc mesenteroides NRRL B-1355, which synthesizes an alternating (alpha)-(1(---\u3e)3), (alpha)-(1(---\u3e)6)-D-glucan from sucrose, was isolated from the culture supernatant fluid of cultures of this organism. The most effective method for accomplishing this was hydrophobic chromatography on phenoxyacetyl cellulose. Alternansucrase was shown to synthesize alternan and to form both (alpha)-(1(---\u3e)6) and (alpha)-(1(---\u3e)3) glucosidic bonds by acceptor reactions with low-molecular-weight saccharides in the presence of sucrose, but an (alpha)-(1(---\u3e)3) bond was synthesized only when an (alpha)-(1(---\u3e)6) glucosidic bond was present at the nonreducing end of the acceptor. Acceptor reactions occurred by transfer of glucosyl units from sucrose to the nonreducing ends of oligosaccharide acceptors;A mixture of two exocellular glucansucrases from L. mesenteroides NRRL B-742 was found to be capable of transferring glucosyl units from sucrose to L. mesenteroides B-512F dextran, to form (alpha)-(1(---\u3e)3) branch linkages via acceptor reactions. It was demonstrated that only one of the two glucansucrases present in the mixture was responsible for these branching reactions; this enzyme is a dextransucrase which forms a dextran having an (alpha)-(1(---\u3e)6) backbone chain with a high percentage of single glucosyl branches linked (alpha)-(1(---\u3e)3) to the main chain. This percentage of branch points can vary, depending on the conditions under which the dextran is synthesized;A glucansucrase from Streptococcus mutans 6715, which produces a highly branched, water-soluble dextran, was found to be capable of forming (alpha)-(1(---\u3e)3) branch linkages in the same manner as the B-742 S dextransucrase, i.e., by acceptor reactions with relatively unbranched dextran, such as that from L. mesenteroides B-512F. This streptococcal dextransucrase was stimulated by the addition of exogenous dextrans. The stimulation was greatest with relatively unbranched dextrans, while more highly branched dextrans were less effective in their ability to stimulate S. mutans 6715 dextransucrase. Other (alpha)-D-glucans, such as glycogen, pullulan, and alternan, did not stimulate;The dextransucrase from S. mutans 6715 was able to utilize alternate glucosyl donors, such as dextran, maltotriose, panose, and isomaltodextrins containing three or more glucose units, in what could be considered the reverse of acceptor reactions

Structural analysis of the α-D-glucan produced by the sourdough isolate Lactobacillus brevis E25

Cereal-associated Lactic Acid Bacteria (LAB) are well known for homopolymeric exopolysaccharide (EPS) production. Herein, the structure of an EPS isolated from sourdough isolate Lactobacillus brevis E25 was determined. A modified BHI medium was used for production of EPS-E25 in order to eliminate potential contaminants. Analysis of sugar monomers in EPS revealed that glucose was the only sugar present. Structural characterisation of EPS by NMR and methylation analysis revealed that E25 produced a highly branched α-glucan with (α1→ 3) and (α1→6) glycosidic linkages, and was similar in structure to a previously reported EPS from Lactobacillus reuteri 180. The 1H and 13C NMR data were contrasted with newly recorded data for known polysaccharides (alternan, commercial dextran) which also contain α-(1,3,6)Glc branch points. It was found in both E25 EPS and alternan that NMR parameters could be used to distinguish glucose residues that had the same substitution pattern but occupied different positions in the structure

Halo globular clusters observed with AAOmega: dark matter content, metallicity and tidal heating

Globular clusters have proven to be essential to our understanding of many important astrophysical phenomena. Here we analyse spectroscopic observations of ten Halo globular clusters to determine their dark matter content, their tidal heating by the Galactic disc and halo, describe their metallicities and the likelihood that Newtonian dynamics explain their kinematics. We analyse a large number of members in all clusters, allowing us to address all these issues together, and we have included NGC 288 and M30 to overlap with previous studies. We find that any flattening of the velocity dispersion profiles in the outer regions of our clusters can be explained by tidal heating. We also find that all our GCs have M/L_V < 5, therefore, we infer the observed dynamics do not require dark matter, or a modification of gravity. We suggest that the lack of tidal heating signatures in distant clusters indicates the Halo is not triaxial. The isothermal rotations of each cluster are measured, with M4 and NGC 288 exhibiting rotation at a level of 0.9 +/- 0.1 km/s and 0.25 +/- 0.15 km/s, respectively. We also indirectly measure the tidal radius of NGC 6752, determining a more realistic figure for this cluster than current literature values. Lastly, an unresolved and intriguing puzzle is uncovered with regard to the cooling of the outer regions of all ten clusters.Comment: 12 pages, 8 figures, 1 table. Accepted for publication in MNRAS

The scientific foundations and associated injury risks of early soccer specialisation

Early specialisation is characterised by formal participation in a single sport at the exclusion of others. Limited data are available to support this approach in the development of soccer players who attain elite status later in life. Of growing concern is the associated increased risk of injury and suggestions that single sport specialisation is a risk factor independent of age, growth, biological maturation and training volumes In the United Kingdom, elite soccer organisations have recently adopted an early sport specialisation approach following the introduction of the Elite Player Performance Plan. A key tenet of this programme is increased opportunities for training through a marked rise in the specified on-pitch hours per week. The accumulation of high training hours may be less of a relevant marker for success, and the impact of such a significant increase in training volume for young athletes who are experiencing a range of growth and maturational processes is currently unknown. This critical commentary includes an evidence based discussion of the effectiveness of early sport specialisation and the potential injury risks associated with such programmes placing a specific focus on elite male youth soccer players. Available data indicate that modifications to the existing EPPP framework could enhance player development and reduce injury risk. Proposed alterations include reduced volume of soccer specific training at key stages of growth and maturation and guidelines for the provision of a greater variety of physical activities that are integrated within other programme components

Low-Mass X-ray Binaries and Globular Clusters in Centaurus A

We present results of Hubble Space Telescope and Chandra X-ray Observatory observations of globular clusters (GCs) and low-mass X-ray binaries (LMXBs) in the central regions of Centaurus A. Out of 440 GC candidates we find that 41 host X-ray point sources that are most likely LMXBs. We fit King models to our GC candidates in order to measure their structural parameters. We find that GCs that host LMXBs are denser and more compact, and have higher encounter rates and concentrations than the GC population as a whole. We show that the higher concentrations and masses are a consequence of the dependence of LMXB incidence on central density and size plus the general trend for denser GCs to have higher masses and concentrations. We conclude that neither concentration nor mass are fundamental variables in determining the presence of LMXBs in GCs, and that the more fundamental parameters relate to central density and size.Comment: 4 pages, 2 figures. Accepted for publication in ApJ Letter

Forest biodiversity, ecosystem functioning and the provision of ecosystem services

Forests are critical habitats for biodiversity and they are also essential for the provision of a wide range of ecosystem services that are important to human well-being. There is increasing evidence that biodiversity contributes to forest ecosystem functioning and the provision of ecosystem services. Here we provide a review of forest ecosystem services including biomass production, habitat provisioning services, pollination, seed dispersal, resistance to wind storms, fire regulation and mitigation, pest regulation of native and invading insects, carbon sequestration, and cultural ecosystem services, in relation to forest type, structure and diversity. We also consider relationships between forest biodiversity and multifunctionality, and trade-offs among ecosystem services. We compare the concepts of ecosystem processes, functions and services to clarify their definitions. Our review of published studies indicates a lack of empirical studies that establish quantitative and causal relationships between forest biodiversity and many important ecosystem services. The literature is highly skewed; studies on provisioning of nutrition and energy, and on cultural services, delivered by mixed-species forests are under-represented. Planted forests offer ample opportunity for optimising their composition and diversity because replanting after harvesting is a recurring process. Planting mixed-species forests should be given more consideration as they are likely to provide a wider range of ecosystem services within the forest and for adjacent land uses. This review also serves as the introduction to this special issue of Biodiversity and Conservation on various aspects of forest biodiversity and ecosystem services

Do agile managed information systems projects fail due to a lack of emotional intelligence?

YesAgile development methodologies (ADM) have become a widely implemented project management approach in Information Systems (IS). Yet, along with its growing popularity, the amount of concerns raised in regard to human related challenges caused by applyingADMare rapidly increasing. Nevertheless, the extant scholarly literature has neglected to identify the primary origins and reasons of these challenges. The purpose of this study is therefore to examine if these human related challenges are related to a lack of Emotional Intelligence (EI) by means of a quantitative approach. Froma sample of 194 agile practitioners, EI was found to be significantly correlated to human related challenges in agile teams in terms of anxiety, motivation, mutual trust and communication competence. Hence, these findings offer important new knowledge for IS-scholars, project managers and human resource practitioners, about the vital role of EI for staffing and training of agile managed IS-projects

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570