2,766 research outputs found

    Revealing natural relationships among arbuscular mycorrhizal fungi: culture line BEG47 represents Diversispora epigaea, not Glomus versiforme

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    Background: Understanding the mechanisms underlying biological phenomena, such as evolutionarily conservative trait inheritance, is predicated on knowledge of the natural relationships among organisms. However, despite their enormous ecological significance, many of the ubiquitous soil inhabiting and plant symbiotic arbuscular mycorrhizal fungi (AMF, phylum Glomeromycota) are incorrectly classified. Methodology/Principal Findings: Here, we focused on a frequently used model AMF registered as culture BEG47. This fungus is a descendent of the ex-type culture-lineage of Glomus epigaeum, which in 1983 was synonymised with Glomus versiforme. It has since then been used as ‘G. versiforme BEG47’. We show by morphological comparisons, based on type material, collected 1860–61, of G. versiforme and on type material and living ex-type cultures of G. epigaeum, that these two AMF species cannot be conspecific, and by molecular phylogenetics that BEG47 is a member of the genus Diversispora. Conclusions: This study highlights that experimental works published during the last >25 years on an AMF named ‘G. versiforme’ or ‘BEG47’ refer to D. epigaea, a species that is actually evolutionarily separated by hundreds of millions of years from all members of the genera in the Glomerales and thus from most other commonly used AMF ‘laboratory strains’. Detailed redescriptions substantiate the renaming of G. epigaeum (BEG47) as D. epigaea, positioning it systematically in the order Diversisporales, thus enabling an evolutionary understanding of genetical, physiological, and ecological traits, relative to those of other AMF. Diversispora epigaea is widely cultured as a laboratory strain of AMF, whereas G. versiforme appears not to have been cultured nor found in the field since its original description

    Proximal Resection Margin in Ivor-Lewis Oesophagectomy for Cancer

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    OBJECTIVE: The purpose of this study was to investigate whether a long proximal oesophageal resection margin (PRM) is associated with improved survival after oesophagectomy for cancer and to identify the optimal margin to aim for in this patient group. METHODS: A prospectively maintained database identified 174 patients who underwent Ivor-Lewis oesophagectomy for cancer. Demographic, clinical, and pathological data were collected. X-tile software was used to identify the optimal resection point. Two models were analysed: single point resection with comparison of two groups (short and long), and two resection points with three groups (short, medium, and long) to provide a range. RESULTS: The median PRM was 4.0 cm (interquartile range: 2.5-6.0 cm). After adjustment for significant confounders, multivariable Cox PH analysis demonstrated that the optimal resection margin was 1.7 cm, and in the three-group analysis the optimum PRM was between 1.7 and 3 cm. In the two-group analysis, the long margin had no effect on DFS (p = 0.37), but carried a significantly improved overall survival (hazard ratio [HR] = 0.46, 95 % confidence interval [CI] 0.25-0.87, p = 0.02). In the three-group analysis, the medium and long groups had improved OS compared with the short group (on average 54 %, HR ≥ 0.45, p ≤ 0.04). The 5-year disease-free and overall survival rates were highest in the medium PRM group (48 and 57 % respectively). CONCLUSIONS: Optimal survival following oesophagectomy for cancer is achieved with a PRM > 1.7 cm, but a PRM > 3 cm does not yield a further survival advantage. Thus, the optimal PRM is likely to be between 1.7 and 3 cm

    Frontal sinus mucocele with orbital extension drained via a combined upper lid skin crease and endoscopic approach.

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    This case report discusses the ophthalmic complications of frontal sinus mucoceles and describes the favorable long-term surgical outcomes of a combined endoscopic and upper-lid skin crease drainage approach carried out jointly with otorhinolaryngology. A 47-year-old single mother presented to eye casualty with markedly swollen eyelids and visual acuity of 6/6 in the left eye, no perception of light in the right. Ophthalmic examination revealed right-sided hypoglobus and proptosis with exposure keratopathy inferiorly. There was complete ophthalmoplegia in the right eye and a hemorrhagic optic disc visible on fundoscopy. CT orbit with contrast confirmed a diagnosis of giant frontal mucocele with orbital extension. The patient underwent mucocele drainage via a modified anterior orbitotomy approach and FESS (Functional Endoscopic Sinus Surgery) drainage performed jointly with otorhinolaryngology. Two weeks post-operatively her proptosis was resolving and by three months she had regained full extraocular motility. As expected, vision was not restored in the right eye. At one year, the patient's upper lid skin crease scar was completely buried in the eyelid's natural contour, and repeat CT scanning confirmed no re-stenosis or mucocele recurrence. This case demonstrates, that a multidisciplinary approach to far-lateral frontal sinus mucoceles with orbital extension and ophthalmic complications which combines an upper lid skin crease incision with FESS drainage, allows adequate access to the frontal sinus while preserving cosmesis

    Evidence for Pervasive Adaptive Protein Evolution in Wild Mice

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    The relative contributions of neutral and adaptive substitutions to molecular evolution has been one of the most controversial issues in evolutionary biology for more than 40 years. The analysis of within-species nucleotide polymorphism and between-species divergence data supports a widespread role for adaptive protein evolution in certain taxa. For example, estimates of the proportion of adaptive amino acid substitutions (alpha) are 50% or more in enteric bacteria and Drosophila. In contrast, recent estimates of alpha for hominids have been at most 13%. Here, we estimate alpha for protein sequences of murid rodents based on nucleotide polymorphism data from multiple genes in a population of the house mouse subspecies Mus musculus castaneus, which inhabits the ancestral range of the Mus species complex and nucleotide divergence between M. m. castaneus and M. famulus or the rat. We estimate that 57% of amino acid substitutions in murids have been driven by positive selection. Hominids, therefore, are exceptional in having low apparent levels of adaptive protein evolution. The high frequency of adaptive amino acid substitutions in wild mice is consistent with their large effective population size, leading to effective natural selection at the molecular level. Effective natural selection also manifests itself as a paucity of effectively neutral nonsynonymous mutations in M. m. castaneus compared to humans

    Diminished temperature and vegetation seasonality over northern high latitudes

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    Global temperature is increasing, especially over northern lands (>50° N), owing to positive feedbacks1. As this increase is most pronounced in winter, temperature seasonality (ST)—conventionally defined as the difference between summer and winter temperatures—is diminishing over time2, a phenomenon that is analogous to its equatorward decline at an annual scale. The initiation, termination and performance of vegetation photosynthetic activity are tied to threshold temperatures3. Trends in the timing of these thresholds and cumulative temperatures above them may alter vegetation productivity, or modify vegetation seasonality (SV), over time. The relationship between ST and SV is critically examined here with newly improved ground and satellite data sets. The observed diminishment of ST and SV is equivalent to 4° and 7° (5° and 6°) latitudinal shift equatorward during the past 30 years in the Arctic (boreal) region. Analysis of simulations from 17 state-of-the-art climate models4 indicates an additional STdiminishment equivalent to a 20° equatorward shift could occur this century. How SV will change in response to such large projected ST declines and the impact this will have on ecosystem services5 are not well understood. Hence the need for continued monitoring6 of northern lands as their seasonal temperature profiles evolve to resemble thosefurther south.Lopullinen vertaisarvioitu käsikirjoitu

    Sensory Electrical Stimulation Improves Foot Placement during Targeted Stepping Post-Stroke

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    Proper foot placement is vital for maintaining balance during walking, requiring the integration of multiple sensory signals with motor commands. Disruption of brain structures post-stroke likely alters the processing of sensory information by motor centers, interfering with precision control of foot placement and walking function for stroke survivors. In this study, we examined whether somatosensory stimulation, which improves functional movements of the paretic hand, could be used to improve foot placement of the paretic limb. Foot placement was evaluated before, during, and after application of somatosensory electrical stimulation to the paretic foot during a targeted stepping task. Starting from standing, twelve chronic stroke participants initiated movement with the non-paretic limb and stepped to one of five target locations projected onto the floor with distances normalized to the paretic stride length. Targeting error and lower extremity kinematics were used to assess changes in foot placement and limb control due to somatosensory stimulation. Significant reductions in placement error in the medial–lateral direction (p = 0.008) were observed during the stimulation and post-stimulation blocks. Seven participants, presenting with a hip circumduction walking pattern, had reductions (p = 0.008) in the magnitude and duration of hip abduction during swing with somatosensory stimulation. Reductions in circumduction correlated with both functional and clinical measures, with larger improvements observed in participants with greater impairment. The results of this study suggest that somatosensory stimulation of the paretic foot applied during movement can improve the precision control of foot placement

    Changes in paediatric respiratory infections at a UK teaching hospital 2016–2021; impact of the SARS-CoV-2 pandemic

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    Objective: To describe the impact of the SARS-CoV-2 pandemic on the incidence of paediatric viral respiratory tract infection in Oxfordshire, UK. Methods: Data on paediatric Emergency Department (ED) attendances (0–15 years inclusive), respiratory virus testing, vital signs and mortality at Oxford University Hospitals were summarised using descriptive statistics. Results: Between 1-March-2016 and 30-July-2021, 155,056 ED attendances occurred and 7,195 respiratory virus PCRs were performed. Detection of all pathogens was suppressed during the first national lockdown. Rhinovirus and adenovirus rates increased when schools reopened September-December 2020, then fell, before rising in March-May 2021. The usual winter RSV peak did not occur in 2020/21, with an inter-seasonal rise (32/1,000 attendances in 0–3 yr olds) in July 2021. Influenza remained suppressed throughout. A higher paediatric early warning score (PEWS) was seen for attendees with adenovirus during the pandemic compared to pre-pandemic (p = 0.04, Mann-Witney U test), no other differences in PEWS were seen. Conclusions: SARS-CoV-2 caused major changes in the incidence of paediatric respiratory viral infection in Oxfordshire, with implications for clinical service demand, testing strategies, timing of palivizumab RSV prophylaxis, and highlighting the need to understand which public health interventions are most effective for preventing respiratory virus infections

    Neural Network Parameterizations of Electromagnetic Nucleon Form Factors

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    The electromagnetic nucleon form-factors data are studied with artificial feed forward neural networks. As a result the unbiased model-independent form-factor parametrizations are evaluated together with uncertainties. The Bayesian approach for the neural networks is adapted for chi2 error-like function and applied to the data analysis. The sequence of the feed forward neural networks with one hidden layer of units is considered. The given neural network represents a particular form-factor parametrization. The so-called evidence (the measure of how much the data favor given statistical model) is computed with the Bayesian framework and it is used to determine the best form factor parametrization.Comment: The revised version is divided into 4 sections. The discussion of the prior assumptions is added. The manuscript contains 4 new figures and 2 new tables (32 pages, 15 figures, 2 tables

    Polymorphism in the neurofibromin gene, Nf1, is associated with antagonistic selection on wing size and development time in Drosophila melanogaster

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    In many invertebrates, body size shows genetically based clines, with size increasing in colder climates. Large body size is typically associated with prolonged development times. We consider variation in the CNS-specific gene neurofibromin 1 (Nf1) and its association with body size and development time. We identified two major Nf1 haplotypes in natural populations, Nf1-insertion-A and Nf1-deletion-G. These haplotypes are characterized by a 45-base insertion/deletion (INDEL) in Nf1 intron 2 and an A/G synonymous substitution (locus L17277). Linkage disequilibrium (LD) between the INDEL and adjacent sites is high but appears to be restricted within the Nf1 gene interval. In Australia, the frequency of the Nf1-insertion-A haplotype increases with latitude where wing size is larger, independent of the chromosomal inversion In(3R)Payne. Unexpectedly, the Nf1-insertion-A haplotype is negatively associated with wing size. We found that the Nf1-insertion-A haplotype is enriched in females with shorter development time. This suggests that the Nf1 haplotype cline may be driven by selection for development time rather than size; females from southern (higher latitude) D. melanogaster populations maintain a rapid development time despite being relatively larger, and the higher incidence of Nf1-insertion-A in Southern Australia may contribute to this pattern, whereas the effects of the Nf1 haplotypes on size may be countered by other loci with antagonistic effects on size and development time. Our results point to the potential complexity involved in identifying selection on genetic variants exhibiting pleiotropic effects when studies are based on spatial patterns or association studies
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