Analysis of Prototype Foamy Virus particle-host cell interaction with autofluorescent retroviral particles

<p>Abstract</p> <p>Background</p> <p>The foamy virus (FV) replication cycle displays several unique features, which set them apart from orthoretroviruses. First, like other B/D type orthoretroviruses, FV capsids preassemble at the centrosome, but more similar to hepadnaviruses, FV budding is strictly dependent on cognate viral glycoprotein coexpression. Second, the unusually broad host range of FV is thought to be due to use of a very common entry receptor present on host cell plasma membranes, because all cell lines tested in vitro so far are permissive.</p> <p>Results</p> <p>In order to take advantage of modern fluorescent microscopy techniques to study FV replication, we have created FV Gag proteins bearing a variety of protein tags and evaluated these for their ability to support various steps of FV replication. Addition of even small N-terminal HA-tags to FV Gag severely impaired FV particle release. For example, release was completely abrogated by an N-terminal autofluorescent protein (AFP) fusion, despite apparently normal intracellular capsid assembly. In contrast, C-terminal Gag-tags had only minor effects on particle assembly, egress and particle morphogenesis. The infectivity of C-terminal capsid-tagged FV vector particles was reduced up to 100-fold in comparison to wild type; however, infectivity was rescued by coexpression of wild type Gag and assembly of mixed particles. Specific dose-dependent binding of fluorescent FV particles to target cells was demonstrated in an Env-dependent manner, but not binding to target cell-extracted- or synthetic- lipids. Screening of target cells of various origins resulted in the identification of two cell lines, a human erythroid precursor- and a zebrafish- cell line, resistant to FV Env-mediated FV- and HIV-vector transduction.</p> <p>Conclusions</p> <p>We have established functional, autofluorescent foamy viral particles as a valuable new tool to study FV - host cell interactions using modern fluorescent imaging techniques. Furthermore, we succeeded for the first time in identifying two cell lines resistant to Prototype Foamy Virus Env-mediated gene transfer. Interestingly, both cell lines still displayed FV Env-dependent attachment of fluorescent retroviral particles, implying a post-binding block potentially due to lack of putative FV entry cofactors. These cell lines might ultimately lead to the identification of the currently unknown ubiquitous cellular entry receptor(s) of FVs.</p

Quality of care assessment in geriatric evaluation and management units: construction of a chart review tool for a tracer condition

<p>Abstract</p> <p>Background</p> <p>The number of elderly people requiring hospital care is growing, so, quality and assessment of care for elders are emerging and complex areas of research. Very few validated and reliable instruments exist for the assessment of quality of acute care in this field. This study's objective was to create such a tool for Geriatric Evaluation and Management Units (GEMUs).</p> <p>Methods</p> <p>The methodology involved a reliability and feasibility study of a retrospective chart review on 934 older inpatients admitted in 49 GEMUs during the year 2002–2003 for fall-related trauma as a tracer condition. Pertinent indicators for a chart abstraction tool, the Geriatric Care Tool (GCT), were developed and validated according to five dimensions: access to care, comprehensiveness, continuity of care, patient-centred care and appropriateness. Consensus methods were used to develop the content. Participants were experts representing eight main health care professions involved in GEMUs from 19 different sites. Items associated with high quality of care at each step of the multidisciplinary management of patients admitted due to falls were identified. The GCT was tested for intra- and inter-rater reliability using 30 medical charts reviewed by each of three independent and blinded trained nurses. Kappa and agreement measures between pairs of chart reviewers were computed on an item-by-item basis.</p> <p>Results</p> <p>Three quarters of 169 items identifying the process of care, from the case history to discharge planning, demonstrated good agreement (kappa greater than 0.40 and agreement over 70%). Indicators for the appropriateness of care showed less reliability.</p> <p>Conclusion</p> <p>Content validity and reliability results, as well as the feasibility of the process, suggest that the chart abstraction tool can gather standardized and pertinent clinical information for further evaluating quality of care in GEMU using admission due to falls as a tracer condition. However, the GCT should be evaluated in other models of acute geriatric units and new strategies should be developed to improve reliability of peer assessments in characterizing the quality of care for elderly patients with complex conditions.</p

Perceptions of clinicians and staff about the use of digital technology in primary care: qualitative interviews prior to implementation of a computer-facilitated 5As intervention

BACKGROUND: Digital health interventions using hybrid delivery models may offer efficient alternatives to traditional behavioral counseling by addressing obstacles of time, resources, and knowledge. Using a computer-facilitated 5As (ask, advise, assess, assist, arrange) model as an example (CF5As), we aimed to identify factors from the perspectives of primary care providers and clinical staff that were likely to influence introduction of digital technology and a CF5As smoking cessation counseling intervention. In the CF5As model, patients self-administer a tablet intervention that provides 5As smoking cessation counseling, produces patient and provider handouts recommending next steps, and is followed by a patient-provider encounter to reinforce key cessation messages, provide assistance, and arrange follow-up. METHODS: Semi-structured in-person interviews of administrative and clinical staff and primary care providers from three primary care clinics. RESULTS: Thirty-five interviews were completed (12 administrative staff, ten clinical staff, and 13 primary care providers). Twelve were from an academic internal medicine practice, 12 from a public hospital academic general medicine clinic, and 11 from a public hospital HIV clinic. Most were women (91 %); mean age (SD) was 42 years (11.1). Perceived usefulness of the CF5As focused on its relevance for various health behavior counseling purposes, potential gains in counseling efficiency, confidentiality of data collection, occupying patients while waiting, and serving as a cue to action. Perceived ease of use was viewed to depend on the ability to accommodate: clinic workflow; heavy patient volumes; and patient characterisitics, e.g., low literacy. Social norms potentially affecting implementation included beliefs in the promise/burden of technology, priority of smoking cessation counseling relative to other patient needs, and perception of CF5As as just “one more thing to do” in an overburdened system. The most frequently cited facilitating conditions were staffing levels and smoking cessation resources and training; the most cited hindering factors were visit time constraints and patients’ complex health care needs. CONCLUSIONS: Integrating CF5As and other technology-enhanced behavioral counseling interventions in primary care requires flexibility to accommodate work flow and perceptions of overload in dynamic environments. Identifying factors that promote and hinder CF5As adoption could inform implementation of other CF behavioral health interventions in primary care

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Partnerwahl, Sexualdimorphismus & Populationsunterschiede in Chorthippus biguttulus

Die Heuschreckenart Chorthippus biguttulus (Orthoptera: Acrididae) ist ein Modellorganismus für akustische Kommunikation. Die Männchen stridulieren durch Reiben des Hinterbeins gegen eine Flügelvene. Diese Dieser Gesang bietet Weibchen Informationen über Artzugehörigkeit, Geschlecht und u.U. die Qualität. Rezeptive Weibchen antworten auf arteigene und attraktive Gesänge. Ich untersuchte, welche Informationen der Männchengesang enthält, wie diese sich in Gesangsparametern manifestieren und welche Informationen rezipiert werden. Ich untersuchte Abhängigkeiten zwischen Gesang und Temperatur, Alter, Morphologie und Immunkompetenz. Ebenfalls testete ich auf eine Infektion mit Wolbachia sp.. Mit Playback-Versuchen wurde die Präferenz der Weibchen getestet. Der Sexualdimorphismus, Populationsunterschiede und Unterschiede zwischen Freiland- und F1-Populationen wurden untersucht. Es konnte gezeigt werden, dass die Männchengesänge in geringem Maße altersabhängig waren während sie Temperatur den Gesang stark beeinflusst. Länger andauernde Nymphenphasen induzierten veränderte Gesangsmerkmale. Größere und schwerere Beine korrelierten mit dem Onsetsowie der Versdauer und der Pausendauer. Die Phasenverschiebung der Hinterbeine hing stark mit der Störpausentiefe und der Thoraxbreite zusammen. Die Werte der Immunkompetenz korrelierten positiv mit dem Onset des Gesangs des jeweiligen Männchens sowie der Femurlänge. Die Weibchen bevorzugten Männchengesänge, die tiefe Offsets, lange Periode, bzw. Silben, geringe Störpausen und besonders lange Versdauern aufwiesen. Die Tiere zeigten einen hohen Grad an Sexualdimorphismus in Morphologie und Gesang. Ebenfalls waren starke Unterschiede in fast allen untersuchten Morphologiemerkmalen und den meisten Gesangsparametern verschiedener Populationen von Männchen festzustellen, wobei die Weibchenpräferenzen ähnlich waren und der artspezifische Parameter, das Silben-Pausen-Verhältnis, sich nicht unterschied.The grasshopper Chorthippus biguttulus (Orthoptera: Acrididae) is a model organism for acoustic communication. The males stridulate by rubbing the hind legs against their forewings. The "song" is species-specific and contains information about the gender and perhaps about the quality. Receptive females answer by singing, if the male song is attractive. I worked on the question, which information about the male is in the song, which song parameters contain the information and which of these information is received by the females. I tested correlations between the song parameters and temperature, age, morphology and immunocompetence and I tested for an infection with Wolbachia sp.. The females’ preferences on male songs were tested with playback-experiments. I investigated the sexual size dimorphism and behavioral differences and the differences in these parameters of animals of different sites in Germany and of laboratory and field animals. The male songs were on a small scale age-dependent. Temporal parameters) depended very much from the temperature and decrease with higher temperatures. The developmental time correlated with the duration of the syllables, the onset variances and the gaps in the syllable. Males with longer and heavier legs produced higher onset, longer verses and longer pauses. The gaps in the syllable amplitude and the width of the thorax correlated with the phase shifting of the hind legs. The immunocompetence rate was positively correlated with the onset and the length of the femur. Females preferred male songs, which contained deep offsets, long periods (syllables), small gaps and long verse durations. The species showed a high degree on sexual dimorphism in morphology and the song parameters. The animals of different populations differed significantly in almost every morphology parameter and a lot of song parameters, while the syllable-to-pause-ration (species-specific) was constant. The females preference of the different sites were similar