Genetic diversity of eukaryotic ultraphytoplankton in the Gulf of Naples during an annual cycle

Eukaryotic ultraphytoplankton (<5 μm) are an important component of phytoplankton populations, Dot blot hybridisation analysis using class level 16S rRNA gene probes as well as clone libraries were used to investigate the diversity of these ultraphytoplankton during a 15 mo period (2003 to 2004) in the Gulf of Naples. Hybridisation data showed the presence of 3 main classes, Cryptophyceae, Chrysophyceae and Prymnesiophyceae, along with lower signals from the Pelagophyceae. Clone libraries also contained these 4 classes as well as sequences from the Dictyochophyceae, Bacillariophyceae and Prasinophyceae. However, the Prymnesiophyceae gave the dominant hybridisation signal and constituted the majority of each clone library. Their diversity, with a total of 190 sequences belonging to 114 operational taxonomic units (OTUs), probably allows them to dominate the ultraphytoplankton throughout the whole year under differing environmental conditions. Over 100 of these OTUs were unique to different libraries, suggesting a succession of different taxa during the year. The Cryptophyceae were present most of the year with 1 OTU, corresponding to a Plagioselmis prolonga strain from the Gulf of Naples, being the dominant taxon (28 % of sequences). A striking result was the high hybridisation signal from the Chrysophyceae, which showed a preference for the summer months. The Pelagophyceae were present between December and March. Most (80 %) of the sequences found in the clone libraries were not identical to available 16S rRNA gene sequences, indicating a high amount of hidden diversity for these algal classes. However, sequences from Prasinophyceae Clade II (Mamiellales) were not detected in the clone libraries

Electron microscopic analysis of rotavirus assembly-replication intermediates

AbstractRotaviruses (RVs) replicate their segmented, double-stranded RNA genomes in tandem with early virion assembly. In this study, we sought to gain insight into the ultrastructure of RV assembly-replication intermediates (RIs) using transmission electron microscopy (EM). Specifically, we examined a replicase-competent, subcellular fraction that contains all known RV RIs. Three never-before-seen complexes were visualized in this fraction. Using in vitro reconstitution, we showed that ~15-nm doughnut-shaped proteins in strings were nonstructural protein 2 (NSP2) bound to viral RNA transcripts. Moreover, using immunoaffinity-capture EM, we revealed that ~20-nm pebble-shaped complexes contain the viral RNA polymerase (VP1) and RNA capping enzyme (VP3). Finally, using a gel purification method, we demonstrated that ~30–70-nm electron-dense, particle-shaped complexes represent replicase-competent core RIs, containing VP1, VP3, and NSP2 as well as capsid proteins VP2 and VP6. The results of this study raise new questions about the interactions among viral proteins and RNA during the concerted assembly–replicase process

Understanding Clinicians’ Perceived Barriers and Facilitators to Optimal Use of Acute Oxygen Therapy in Adults

Background: Supplemental oxygen is commonly administered to patients in acute care. It may cause harm when used inappropriately. Guidelines recommend prescription of acute oxygen, yet adherence is poor. We aimed to identify barriers and facilitators to practicing in accordance with the evidence-based Thoracic Society of Australia and New Zealand (TSANZ) oxygen guideline, and to determine the beliefs and attitudes relating to acute oxygen therapy. Methods: A national cross-sectional survey was conducted. The survey consisted of 3 sections: (1) introduction and participant characteristics; (2) opinion/beliefs, knowledge and actions about oxygen therapy and other drugs; and (3) barriers and facilitators to use of the TSANZ guideline. Convenience sampling was employed. A paper-based survey was distributed at the TSANZ Annual Scientific Meeting. An online survey was emailed to the TSANZ membership and to John Hunter Hospital’s clinical staff. Results: Responses were received from 133 clinicians: 52.6% nurses, 30.1% doctors, and 17.3% other clinicians. Over a third (37.7%) were unaware/unsure of the oxygen guideline’s existence. Most (79.8%) believe that oxygen is a drug and should be treated as one. Most (92.4%) stated they only administered it based on clinical need. For four hypothetical cases, there was only one where the majority of participants identified the optimal oxygen saturation. A number of barriers and facilitators were identified when asked about practicing in accordance with the TSANZ guideline. Lack of oxygen equipment, getting doctors to prescribe oxygen and oxygen being treated differently to other drugs were seen as barriers. The guideline itself and multiple clinician characteristics were considered facilitators. Conclusion: There is discordance between clinicians’ beliefs and actions regarding the administration of oxygen therapy and knowledge gaps about optimal oxygen therapy in acute care. Identified barriers and facilitators should be considered when developing evidence-based guidelines to improve dissemination and knowledge exchange

Categorias da motivação na aprendizagem

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Garduação em Engenharia de Produção.Trata-se de um estudo do construto motivacional no campo da psicologia e das ciências da educação. O trabalho parte da análise crítica das teorias motivacionais, principalmente no que se refere aos aspectos da dicotomia entre o carácter intrínseco e extrínseco da motivação. Os elementos associados à lógica da recompensa são analisados como impedidores da motivação. A teoria psicanalítica e o cognitivismo sustentam a hipóteses da constituição do fenômeno motivacional a partir das categorias pulsional e cognitiva. A categoria social irrompe na construção teórica como a finalidade última da motivação. Do desenvolvimento teórico resulta o quadro hipotético de categorias e fatores da motivação na aprendizagem que serve de parâmetro à pesquisa empírica. Os elementos metodológico-epistêmicos e metodológico-técnicos são discutidos à luz da visão qualitativa de investigação. Através da interpretação social dos discursos (nível de aproximação das abordagens da análise do discurso), tornou-se possível a reformulação do quadro hipotético de categorias e fatores da motivação na aprendizagem, bem como, a definição dos fatores com base na sua forma de atuação nos discurso

Mechanism for Coordinated RNA Packaging and Genome Replication by Rotavirus Polymerase VP1

Rotavirus RNA-dependent RNA polymerase, VP1, catalyzes RNA synthesis within a subviral particle. This activity depends on core shell protein VP2. A conserved sequence at the 3′ end of plusstrand RNA templates is important for polymerase association and genome replication. We have determined the structure of VP1 at 2.9 Å resolution, as apoenzyme and in complex with RNA. The cage-like enzyme is similar to reovirus λ3, with four tunnels leading to or from a central, catalytic cavity. A distinguishing characteristic of VP1 is specific recognition, by conserved features of the template-entry channel, of four bases, UGUG, in the conserved 3′ sequence. Well-defined interactions with these bases position the RNA so that its 3′ end overshoots the initiating register, producing a stable but catalytically inactive complex. We propose that specific 3′ end recognition selects rotavirus RNA for packaging and that VP2 activates the auto-inhibited VP1/RNA complex to coordinate packaging and genome replication.Molecular and Cellular Biolog

Testing of a novel questionnaire of Household Exposure to Wood Smoke

Household air pollution from wood smoke (WS), contributes to adverse health effects in both low- and high-income countries. However, measurement of WS exposure has been limited to expensive in-home monitoring and lengthy face-to-face interviews. This paper reports on the development and testing of a novel, self-report nine-item measure of WS exposure, called the Household Exposure to Wood Smoke (HEWS). A sample of 149 individuals using household wood stoves for heating from western states in the U.S., completed the HEWS during the winter months (November to March) of 2013 through 2016 with 30 subjects having in-home particle monitoring. Hard copy or online surveys were completed. Cronbach\u27s alpha (α), intraclass correlations (ICC), exploratory factor analysis (EFA) and tests of associations were done to evaluate reliability and validity of the HEWS. Based on initial analysis, only 9 of the 12 items were retained and entered in the EFA. The EFA did not support a unitary scale as the 9 items demonstrated a 3-factor solution (WS exposure duration, proximity, and intensity) with Cronbach\u27s α of 0.79, 0.91, and 0.62, respectively. ICC was 0.86 of the combined items with single items ranging from 0.46 to 0.95. WS intensity was associated with symptoms and levoglucosan levels, while WS duration was associated with stove and flume maintenance. The three-dimensional HEWS demonstrated internal consistency and test-retest reliability, structural validity, and initial criterion and construct validity

DNA polymerase IV primarily operates outside of DNA replication forks in Escherichia coli

In Escherichia coli, damage to the chromosomal DNA induces the SOS response, setting in motion a series of different DNA repair and damage tolerance pathways. DNA polymerase IV (pol IV) is one of three specialised DNA polymerases called into action during the SOS response to help cells tolerate certain types of DNA damage. The canonical view in the field is that pol IV primarily acts at replisomes that have stalled on the damaged DNA template. However, the results of several studies indicate that pol IV also acts on other substrates, including single-stranded DNA gaps left behind replisomes that re-initiate replication downstream of a lesion, stalled transcription complexes and recombination intermediates. In this study, we use single-molecule time-lapse microscopy to directly visualize fluorescently labelled pol IV in live cells. We treat cells with the DNA-damaging antibiotic ciprofloxacin, Methylmethane sulfonate (MMS) or ultraviolet light and measure changes in pol IV concentrations and cellular locations through time. We observe that only 5±10% of foci induced by DNA damage form close to replisomes, suggesting that pol IV predominantly carries out non-replisomal functions. The minority of foci that do form close to replisomes exhibit a broad distribution of colocalisation distances, consistent with a significant proportion of pol IV molecules carrying out postreplicative TLS in gaps behind the replisome. Interestingly, the proportion of pol IV foci that form close to replisomes drops dramatically in the period 90±180 min after treatment, despite pol IV concentrations remaining relatively constant. In an SOS-constitutive mutant that expresses high levels of pol IV, few foci are observed in the absence of damage, indicating that within cells access of pol IV to DNA is dependent on the presence of damage, as opposed to concentration-driven competition for binding sites