Holocentric Chromosomes of Luzula elegans Are Characterized by a Longitudinal Centromere Groove, Chromosome Bending, and a Terminal Nucleolus Organizer Region

The structure of holocentric chromosomes was analyzed in mitotic cells of Luzula elegans. Light and scanning electron microscopy observations provided evidence for the existence of a longitudinal groove along each sister chromatid. The centromere-specific histone H3 variant, CENH3, colocalized with this groove and with microtubule attachment sites. The terminal chromosomal regions were CENH3-negative. During metaphase to anaphase transition, L. elegans chromosomes typically curved to a sickle-like shape, a process that is likely to be influenced by the pulling forces of microtubules along the holocentric axis towards the corresponding microtubule organizing regions. A single pair of 45S rDNA sites, situated distal to Arabidopsis-telomere repeats, was observed at the terminal region of one chromosome pair. We suggest that the 45S rDNA position in distal centromere-free regions could be required to ensure chromosome stability. Copyright (C) 2011 S. Karger AG, Base

The Aquilegia genome: adaptive radiation and an extraordinarily polymorphic chromosome with a unique history

The columbine genus Aquilegia is a classic example of an adaptive radiation, involving a wide variety of pollinators and habitats. Here we present the genome assembly of A. coerulea "Goldsmith", complemented by high-coverage sequencing data from 10 wild species covering the world-wide distribution. Our analysis reveals extensive allele sharing among species, and sheds light on the complex process of radiation. We also present the remarkable discovery that the evolutionary history of an entire chromosome differed from that of the rest of the genome --- a phenomenon which we do not fully understand, but which highlights the need to consider chromosomes in an evolutionary context

Influenza Epidemiology And Influenza Vaccine Effectiveness During The 2015-2016 Season: Results From The Global Influenza Hospital Surveillance Network

BackgroundThe Global Influenza Hospital Surveillance Network is an international platform whose primary objective is to study severe cases of influenza requiring hospitalization.MethodsDuring the 2015-2016 influenza season, 11 sites in the Global Influenza Hospital Surveillance Network in nine countries (Russian Federation, Czech Republic, Turkey, France, China, Spain, Mexico, India, and Brazil) participated in a prospective, active-surveillance, hospital-based epidemiological study. Influenza infection was confirmed by reverse transcription-polymerase chain reaction. Influenza vaccine effectiveness (IVE) against laboratory-confirmed influenza was estimated using a test-negative approach.Results9882 patients with laboratory results were included of which 2415 (24.4%) were positive for influenza, including 1415 (14.3%) for A(H1N1)pdm09, 235 (2.4%) for A(H3N2), 180 (1.8%) for A not subtyped, 45 (0.5%) for B/Yamagata-lineage, 532 (5.4%) for B/Victoria-lineage, and 33 (0.3%) for B not subtyped. Of included admissions, 39% were<5years of age and 67% had no underlying conditions. The odds of being admitted with influenza were higher among pregnant than non-pregnant women (odds ratio, 2.82 [95% confidence interval (CI), 1.90 to 4.19]). Adjusted IVE against influenza-related hospitalization was 16.3% (95% CI, 0.4 to 29.7). Among patients targeted for influenza vaccination, adjusted IVE against hospital admission with influenza was 16.2% (95% CI, -3.6 to 32.2) overall, 23.0% (95% CI, -3.3 to 42.6) against A(H1N1)pdm09, and-25.6% (95% CI, -86.3 to 15.4) against B/Victoria lineage.ConclusionsThe 2015-2016 influenza season was dominated by A(H1N1)pdm09 and B/Victoria-lineage. Hospitalization with influenza often occurred in healthy and young individuals, and pregnant women were at increased risk of influenza-related hospitalization. Influenza vaccines provided low to moderate protection against hospitalization with influenza and no protection against the predominant circulating B lineage, highlighting the need for more effective and broader influenza vaccines.Wo

Influenza Epidemiology And Influenza Vaccine Effectiveness During The 2016-2017 Season In The Global Influenza Hospital Surveillance Network (Gihsn)

BackgroundThe Global Influenza Hospital Surveillance Network (GIHSN) aims to determine the burden of severe influenza disease and Influenza Vaccine Effectiveness (IVE). This is a prospective, active surveillance and hospital-based epidemiological study to collect epidemiological data in the GIHSN. In the 2016-2017 influenza season, 15 sites in 14 countries participated in the GIHSN, although the analyses could not be performed in 2 sites. A common core protocol was used in order to make results comparable. Here we present the results of the GIHSN 2016-2017 influenza season.MethodsA RT-PCR test was performed to all patients that accomplished the requirements detailed on a common core protocol. Patients admitted were included in the study after signing the informed consent, if they were residents, not institutionalised, not discharged in the previous 30days from other hospitalisation with symptoms onset within the 7days prior to admission. Patients 5years old or more must also complied the Influenza-Like Illness definition. A test negative-design was implemented to perform IVE analysis. IVE was estimated using a logistic regression model, with the formula IVE=(1-aOR)x100, where aOR is the adjusted Odds Ratio comparing cases and controls.ResultsAmong 21,967 screened patients, 10,140 (46.16%) were included, as they accomplished the inclusion criteria, and tested, and therefore 11,827 (53.84%) patients were excluded. Around 60% of all patients included with laboratory results were recruited at 3 sites. The predominant strain was A(H3N2), detected in 63.6% of the cases (1840 patients), followed by B/Victoria, in 21.3% of the cases (618 patients). There were 2895 influenza positive patients (28.6% of the included patients). A(H1N1)pdm09 strain was mainly found in Mexico. IVE could only be performed in 6 sites separately. Overall IVE was 27.24 (95% CI 15.62-37.27. Vaccination seemed to confer better protection against influenza B and in people 2-4years, or 85years old or older. The aOR for hospitalized and testing positive for influenza was 3.02 (95% CI 1.59-5.76) comparing pregnant with non-pregnant women.ConclusionsVaccination prevented around 1 in 4 hospitalisations with influenza. Sparse numbers didn't allow estimating IVE in all sites separately. Pregnancy was found a risk factor for influenza, having 3 times more risk of being admitted with influenza for pregnant women.Wo