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This article aims to provide an overview of the main mechanisms underlying the non-take-up of public provisions by bringing together insights from existing theoretical models and the large body of empirical evidence within Europe and the U.S. We draw on studies based on the rational choice model as well as on insights from psychology and behavioural economics. Whereas most studies are confined to the client level only to explain non-take-up, an important focus of attention here is the way policy design and administration can affect the uptake of public provisions, as well as the role the broader social context plays in understanding non-take-up. In this article, we bring different strands in the literature together and develop a theoretical framework which lists and links the various mechanisms at play. At the same time, we summarise most important empirical findings on the drivers of non-take-up, and focus on lessons from the literature regarding how policies could be redesigned to reduce non-take-up.

Emotion regulation in daily life can serve as a risk or resilience factor during times of crisis. Using the experience sampling method, the current study investigated rumination, savoring, and sharing with others in response to positive and negative events during the early COVID-19 pandemic lockdown measures among adolescents (N = 110, aged 13-20, 89% female). For six days, adolescents reported the intensity and valence of events throughout the day and how much they ruminated and shared about negative events and savored and shared about positive events. We aimed to conceptually replicate pre-pandemic findings and found that relationships between emotion regulation and event intensity were largely replicated: During the pandemic, higher intensity of negative events was associated with ruminating more and higher intensity of positive events was associated with savoring more and sharing more about them. Symptoms of psychopathology (anxiety, depression, and psychoticism) were not associated with ruminating about negative events, contrary to pre-pandemic observations, or sharing about negative events. However, psychopathology symptoms were positively associated with savoring positive events. The current results highlight the importance of context in daily life emotion regulation and suggest that adaptive emotion regulation may look different for adolescents during a major disruption to daily life.

Key symptoms of anxiety include experiencing unpleasant emotions and hyperarousal. Growing evidence suggests the role of delayed affective recovery from stress (DAR) in their maintenance and development on a day-to-day basis. We aimed to investigate whether DAR is linked to current and future anxiety symptoms, independently of depressive symptoms. Self-reported anxiety and depressive symptoms were assessed twice: at Wave 1 (N=1031) and approximately 2.5 years later at Wave 2 (N=171) in a community sample of adolescents. Additionally, at Wave 1, Experience Sampling Method (ESM) was used. Participants reported their momentary affect and stressful occurrences 10 times a day, for six days. Using ESM data and a subtraction method, we construed two variables, i.e., affective valence and arousal reflecting the (un)pleasantness and (hyper)arousal associated with emotions. The time interval for affective recovery was estimated using parametric survival analysis. Prospective associations were tested with multiple regression. Slower valence recovery was associated with higher concurrent anxiety symptoms (p

The COVID-19 pandemic posed a challenge for young people’s positive future orientation and mental health. The current study’s objective was to understand the role of daily-life future orientation and anticipatory emotion regulation in mental health during the pandemic. We used the Experience Sampling Method to investigate Belgian adolescents’ (aged 13 – 21) daily life future orientation and anticipatory emotion regulation in relation to psychopathology symptoms in 2020 (N = 136, 121 females) and 2021 (N = 53, 48 females). Adolescents generally perceived immediate future events more positively than negatively throughout the pandemic, however, differences in future orientation between phases of the pandemic were also observed. Higher psychopathology symptom levels were associated with looking forward to future events less and dreading them more early in the pandemic, and with perceiving immediate future events as less positive in a later phase of the pandemic. Furthermore, expected intensity and importance of immediate future events were related to anticipatory emotion regulation in daily life during the pandemic. The results suggest that adolescents with higher psychopathology symptoms perceive the immediate future more negatively during a crisis. Therefore, clinical interventions to target future orientation during a crisis could be beneficial in supporting and improving young people’s mental health.

In many Western countries local welfare agencies retain large responsibilities in the practical organisation of means-tested support. While this may lead to substantial differences in the application trajectories of prospective claimants, what has garnered little empirical research is how local agencies use their discretion to implement practices that may encourage or discourage take-up. In addition, we know little on the extent to which variation in local implementation is attributable to differences in local conditions. Focusing on Belgium as an interesting case, this article addresses this gap by mapping the variation in local implementation practices in specific aspects of social assistance that are relevant in terms of limiting non-take-up. We assess whether certain local political, socio-demographic or economic characteristics favour implementation practices, using structural equation modelling on custom-collected data on the practical organisation of social assistance application trajectories in 119 Belgian municipalities. The results show that local welfare agencies implement coherent practices regarding information provision, accessibility, trust and the locus of initiative in the claiming process. We find the political orientation of the municipality and the share of foreigners in the municipality to be related with, respectively, shifting the locus of initiative away from the welfare claimant and a focus on information provision.

Adolescent social withdrawal was drastically impacted by the COVID-19 pandemic. As social withdrawal is crucial for adolescent development through its association with both positive and negative developmental outcomes, it is critical to understand how adolescents’ daily-life social withdrawal experiences changed as a result of the pandemic. Using three waves of data from a large longitudinal study, we found that adolescents with lower levels of pre-pandemic social support and social skills reported wanting to be alone less and feeling like an outsider more, both in the early (nT1 = 100) and mid-pandemic (nT2 = 204) waves. In the mid-pandemic wave, adolescents with higher levels of pre-pandemic social support and social skills reported decreases in positive affect compared to the pre-pandemic wave. This indicates that all adolescents experienced a negative impact of the COVID-19 pandemic to some degree, especially with the increased duration of the pandemic.

COVID-19 lockdown measures have profoundly impacted adolescent' daily life, with research suggesting an increase in irritability, stress, loneliness, and family conflict. A potential protective factor is parent-child relationship quality; however, no studies have investigated this. We used data from SIGMA, a longitudinal, experience sampling cohort study, in which N = 173 adolescents aged 11 to 20 were tested before and during COVID-19. Multilevel analyses showed decreased daily-life irritability and increased loneliness from pre- to mid-pandemic. Daily-life stress levels were unchanged. Relationship quality was negatively associated with irritability and loneliness and buffered against the increase in loneliness. Effect sizes were small and do not support a strong effect of the first lockdown on irritability, stress, loneliness, and family conflict in adolescents. ispartof: Journal Of Research On Adolescence vol:31 issue:3 pages:623-644 ispartof: location:United States status: published

Non-take-up of means-tested benefits is a widespread phenomenon which undermines the effectiveness and fairness of social policies. The digitalisation of the welfare state creates new opportunities for proactively contacting people who are potentially entitled to benefits, but do not take up their social rights. In this study, we report on how new data flows were used to reach out to potential beneficiaries of the Increased Reimbursement of health care, a programme targeted at low-income households in Belgium. By randomizing the period in which potential beneficiaries were contacted, we were able to identify a three- to four-fold increase in take-up among those contacted as a result of the outreaching activities. Households that did not respond to the intervention, the never takers, have lower pre-intervention healthcare expenditures. This suggests that non-take-up was reduced primarily among those who would expect to benefit most from receiving the Increased Reimbursement. Exploiting the combination of rich administrative data with experimental evidence, we also find that early responders are mostly older and have higher historic health expenditures than late responders. Furthermore, results point to the need for balancing well the inclusiveness of the intervention with an increased number of applications by ineligible people.

Antarctic sea ice is an important temporal reservoir of iron which can boost primary production in the marginal ice zone during the seasonal melt. While studies have reported that Antarctic fast ice bears high concentrations of iron due to the proximity to coastal sources, less clear is the biogeochemical changes this iron pool undergoes during late spring. Here we describe a 3-weeks? time series of physical and biogeochemical data, including iron, from first-year coastal fast ice sampled near Davis Station (Prydz Bay, East Antarctica) during late austral spring 2015. Our study shows that dissolved and particulate iron concentrations in sea ice were up to two orders of magnitude higher than in under-ice seawater. Furthermore, our results indicate a significant contribution of lithogenic iron from the Vestfold Hills (as deduced from the comparison with crustal element ratios) to the particulate iron pool in fast ice after a blizzard event halfway through the time series. Windblown dust represented approximately 75% of the particulate iron found in the ice and is a potential candidate for keeping concentrations of soluble iron stable during our observations. These results suggest that iron entrapped during ice formation, likely from sediments, as well as local input of coastal dust, support primary productivity in Davis fast ice. As ice-free land areas are likely to expand over the course of the century, this work highlights the need to quantify iron inputs from continental Antarctic dust and its bioavailability for ice algae and phytoplankton. Plain summary Oceanic single-celled algae are the base of the ocean food web and play an important role in the Earth climate. In the Southern Ocean, the growth of these microorganisms is limited by the naturally low concentration of iron in the seawater. Microalgae benefits from the presence of the Antarctic sea ice since iron there are many times concentrated relative to the seawater. Less clear though, is the contribution of the potential sources of iron to the sea ice. We collected and analyzed sea ice cores for a series of parameters, including iron, from first-year coastal sea ice sampled near Davis Station (Prydz Bay, East Antarctica) during late austral spring 2015. Our results suggest that iron entrapped during ice formation, likely from seafloor sediments, as well as dust blown by winds from the neighboring Vestfold Hills, are the main sources of iron to Davis coastal sea ice. Since we can expect the expansion of ice-free areas and exposed grounds over the course of this century, our results highlight the need to quantify the amount of iron coming from continental Antarctic dust and to access if sea algae can access this form of iron for their basic physiological needs.

14 pages, 11 figures, 2 tables, supplementary data https://doi.org/10.1016/j.dsr.2022.103899.-- Data availability: Data presented in this study can be sourced from https://metadata.imas.utas.edu.au/geonetwork/srv/eng/metadata.show?uuid=02364e10-ebc0-463a-b690-2c4ed643733c, Polynyas represent regions of enhanced primary production because of the low, or absent, sea-ice cover coupled with the proximity of nutrient sources. However, studies throughout the Southern Ocean suggest elevated primary production does not necessarily result in increased carbon export. Three coastal polynyas in East Antarctica and an off-shelf region were visited during the austral summer from December 2016 to January 2017 to examine the vertical distribution and concentration of particulate organic carbon (POC). Carbon export was also examined using thorium-234 (234Th) as a proxy at two of the polynyas. Our results show that concentrations and integrated POC stocks were higher within the polynyas compared to the off-shelf sites. Within the polynyas, vertical POC concentrations were higher in the Mertz and Ninnis polynyas compared to the Dalton polynya. Similarly, higher carbon export was measured in the diatom-dominated Mertz polynya, where large particles (>53 μm) represented a significant fraction of the particulate 234Th and POC (average 50% and 39%, respectively), compared to the small flagellate-dominated Dalton polynya, where almost all the particulate 234Th and POC were found in the smaller size fraction (1–53 μm). The POC to Chlorophyll-a ratios suggest that organic matter below the mixed layer in the polynyas consisted largely of fresh phytoplankton at this time of the year. In combination with a parallel study on phytoplankton production at these sites, we find that increased primary production at these polynyas does lead to greater concentrations and export of POC and a higher POC export efficiency, This study was supported by the Australian Government's Cooperative Research Centres through the Antarctic Climate and Ecosystem Cooperative Research Centre, the Australian Antarctic Division research projects AAS 4131 and 4291, and the Institute for Marine and Antarctic Studies, University of Tasmania. L. Ratnarajah also received support from BYONIC (ERC award number 724289). D. Lannuzel was supported by an Australian Research Council Future Fellowship (Project ID L0026677). S. Moreau and C. Genovese were supported by the Australian Research Council's Special Research Initiative for Antarctic Gateway Partnership (Project ID SR140300001). V. Puigcorbé was supported by Edith Cowan University through an Early Career Researcher Grant (G1003456) and an ECU-Collaboration Enhancement Scheme grant (G1003362). V. Puigcorbé received the support of a fellowship from “la Caixa” Foundation (ID 100010434) and from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 847648 (fellowship code 105183). M. Roca-Martí was supported by funding from the Woods Hole Oceanographic Institution's Ocean Twilight Zone study and the Ocean Frontier Institute. [...] This work acknowledges the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)

To infect nondividing cells, HIV-1 needs to cross the nuclear membrane. The importin transportin-SR2 (TRN-SR2 or transportin-3) has been proposed to mediate HIV-1 nuclear import, but the detailed mechanism remains unresolved. The direct interaction of TRN-SR2 with HIV-1 integrase (IN) has been proposed to drive HIV-1 nuclear import. Alternatively, TRN-SR2 may play an indirect role by mediating nuclear import of cleavage and polyadenylation specificity factor 6 (CPSF6). To unravel the role of TRN-SR2, we designed CRISPR/Cas9 guide RNAs targeting different exons of TNPO3. Although this approach failed to generate full knockouts, monoallelic knockout clones were generated with indel mutations. HIV-1 replication was hampered in those clones at the level of HIV-1 nuclear import without an effect on the cellular distribution of the TRN-SR2 cargoes CPSF6 or alternative splicing factor1/pre-mRNA splicing factor SF2 (ASF/SF2). Recombinant ΔV105 TRN-SR2 expressed in clone 15.15 was 2-fold impaired for interaction with HIV-1 IN and classified as an interaction mutant. Our data support a model whereby TRN-SR2 acts as a cofactor of HIV-1 nuclear import without compromising the nuclear import of cellular cargoes. CRISPR/Cas9-induced mutagenesis can be used as a method to generate interface mutants to characterize host factors of human pathogens. IMPORTANCE Combination antiretroviral therapy (cART) effectively controls HIV-1 by reducing viral loads, but it does not cure the infection. Lifelong treatment with cART is a prerequisite for sustained viral suppression. The rapid emergence of drug-resistant viral strains drives the necessity to discover new therapeutic targets. The nuclear import of HIV-1 is crucial in the HIV-1 replication cycle, but the detailed mechanism remains incompletely understood. This study provides evidence that TRN-SR2 directly mediates HIV-1 nuclear import via the interaction with HIV-1 integrase. The interaction between those proteins is therefore a promising target toward a rational drug design which could lead to new therapeutic strategies due to the bottleneck nature of HIV-1 nuclear import. ispartof: MICROBIOLOGY SPECTRUM vol:9 issue:2 ispartof: location:United States status: published

Early findings on the impact of the COVID-19 pandemic on adolescents, suggest that – despite being at the lowest physical health risk – both their mental health and day-to-day social lives are strongly affected. In this longitudinal study, we assessed changes in adolescent psychopathology symptoms, the quality and quantity of daily-life social interactions, and the relationship between social interactions and psychopathology symptoms before and during the pandemic.A sample of n=173 Flemish adolescents (mean age=16.0 at latest measurement; 89% girls) from the SIGMA cohort was tested between January 2018 - June 2019; and between April 27th - May 10th 2020. Subclinical psychopathology was assessed using the Brief Symptom Inventory-53; daily social interactions were assessed in six-day experience sampling periods with ten daily questionnaires.Multilevel linear and logistic regression analyses indicated lower general psychopathology and anxiety symptoms, beyond age effects; fewer face-to-face social interactions, more online social interactions; and higher-quality face-to-face interactions during the pandemic than before. Negative associations between psychopathology and the quality of face-to-face peer and family interactions were stronger during the pandemic than pre-pandemic.The observed decrease and stability in psychopathology symptoms is surprising and potentially reflects resilience. Although digital communication may buffer much of the quarantine-induced distress, the current results imply that high-quality face-to-face interactions with family and peers may have been more powerful in keeping adolescents resilient. As restrictions are lifted and adolescents’ daily lives and social worlds change, it is crucial to learn more about the longer-term effects of the experienced social deprivation.

In the Southern Ocean, polynyas exhibit enhanced rates of primary productivity and represent large seasonal sinks for atmospheric CO2. Three contrasting east Antarctic polynyas were visited in late December to early January 2017: the Dalton, Mertz, and Ninnis polynyas. In the Mertz and Ninnis polynyas, phytoplankton biomass (average of 322 and 354 mg chlorophyll a (Chl a)/m2, respectively) and net community production (5.3 and 4.6 mol C/m2, respectively) were approximately 3 times those measured in the Dalton polynya (average of 122 mg Chl a/m2 and 1.8 mol C/m2). Phytoplankton communities also differed between the polynyas. Diatoms were thriving in the Mertz and Ninnis polynyas but not in the Dalton polynya, where Phaeocystis antarctica dominated. These strong regional differences were explored using physiological, biological, and physical parameters. The most likely drivers of the observed higher productivity in the Mertz and Ninnis were the relatively shallow inflow of iron‐rich modified Circumpolar Deep Water onto the shelf as well as a very large sea ice meltwater contribution. The productivity contrast between the three polynyas could not be explained by (1) the input of glacial meltwater, (2) the presence of Ice Shelf Water, or (3) stratification of the mixed layer. Our results show that physical drivers regulate the productivity of polynyas, suggesting that the response of biological productivity and carbon export to future change will vary among polynyas.

The HIV replication cycle depends on the interaction of viral proteins with proteins of the host. Unraveling host-pathogen interactions during the infection is of great importance for understanding the pathogenesis and the development of antiviral therapies. To date HIV uncoating and nuclear import are the most debated steps of the HIV-1 replication cycle. Despite numerous studies during past decades, there is still much controversy with respect to the identity and the role of viral and host factors involved in these processes. In this review, we provide a comprehensive overview on the role of transportin-SR2 as a host cell factor during active nuclear transport. ispartof: VIRUSES-BASEL vol:13 issue:5 ispartof: location:Switzerland status: published

Ammonium is a fundamental nutrient for phytoplankton growth in seawater and is a key component of the microbial loop. Ammonium measured in parallel with other nutrients is crucial in understanding the small temporal scale changes in oceanographic ecology. Despite the importance of measuring ammonium at sea, owing to its lability, there is no consensus on the best method. The lack of availability of certified reference materials for ammonium in seawater also makes it difficult to assess the accuracy and reproducibility of ammonium measurements. In this study we present a modified segmented flow analysis method using ortho-phthaldialdehyde (OPA) with fluorescence detection to measure ammonium at sea together with four other macro-nutrients (nitrate, nitrite, silicate and phosphate) in near real time. An in-house ammonium quality control (QC) material was produced to improve the accuracy and repeatability of the measurement at sea. The QC was prepared following two different methods and stored in two types of containers. The suitability of the in-house QC’s as a reference material were assessed onboard the RV Investigator in 2018 during two oceanographic voyages, including one on the repeat SR03 CLIVAR transect. This paper describes the production and assessment of the in-house QC for ammonium in seawater, providing groundwork for creating a short-term stable ammonium reference material for sea going voyages. The uncertainty of this method of ammonium measurement was found to be 0.10 μmol/L at ammonium concentration of 1.0 μmol/L. Results show that preparation of the QC inside a laminar flow cabinet and directly into 10 mL polypropylene sample tubes just prior to the commencement of the voyage improved its stability.

Despite potent combination antiretroviral therapy, HIV-1 infection persists due to irreversible integration of the virus in long-living cells of the immune system. The main focus of HIV-1 cure strategies has been on HIV-1 eradication, yet without great success so far. Therefore, HIV-1 remission or a functional cure, whereby the virus is silenced rather than eradicated, is considered as an alternative strategy. Elite controllers, individuals who spontaneously control HIV-1, may point us the way toward a functional HIV-1 cure. In order to achieve such a cure, a profound understanding of the mechanisms controlling HIV-1 expression and silencing is needed. In recent years, evidence has grown that the site of integration as well as the chromatin landscape surrounding the integration site affects the transcriptional state of the provirus. Still, at present, the impact of integration site selection on the establishment and maintenance of the HIV-1 reservoirs remains poorly understood. The discovery of LEDGF/p75 as a binding partner of HIV-1 integrase has led to a better understanding of integration site selection. LEDGF/p75 is one of the important determinants of integration site selection and targets integration toward active genes. In this review, we will provide an overview of the most important determinants of integration site selection. Secondly, we will discuss the chromatin landscape at the integration site and its implications on HIV-1 gene expression and silencing. Finally, we will discuss how interventions that affect integration site selection or modifications of the chromatin could yield a functional cure of HIV-1 infection.

A permanent cure remains the greatest challenge in the field of HIV research. In order to reach this goal, a profound understanding of the molecular mechanisms controlling HIV integration and transcription is needed. Here we provide an overview of recent advances in the field. Lens epithelium-derived growth factor p75 (LEDGF/p75), a transcriptional coactivator, tethers and targets the HIV integrase into transcriptionally active regions of the chromatin through an interaction with the epigenetic mark H3K36me2/3. This finding prompted us to propose a "block-and-lock" strategy to retarget HIV integration into deep latency. A decade ago, we pioneered protein-protein interaction inhibitors for HIV and discovered LEDGINs. LEDGINs are small molecule inhibitors of the interaction between the integrase binding domain (IBD) of LEDGF/p75 and HIV integrase. They modify integration site selection and therefore might be molecules with a "block-and-lock" mechanism of action. Here we will describe how LEDGINs may become part in the future functional cure strategies.

Since Antarctic sea ice covers an area larger than the Antarctic continent itself, the discovery that it can fertilize the Southern Ocean with iron (Fe) has fostered a new breadth of research in recent years. In order to test the hypothesis that Fe-binding organic ligands control the distribution of dissolved iron (DFe) in Antarctic pack ice, iron organic speciation was investigated in samples collected during the Sea Ice Physics and Ecosystem eXperiment-2 (SIPEX-2) voyage in Austral winter/spring 2012. Dissolved Fe was measured using sector field inductively coupled plasma mass spectrometry, and iron organic speciation parameters were determined by competitive ligand equilibration - adsorptive cathodic stripping voltammetry method, using 1-nitroso-2-naphthol (NN) as the added ligand. The concentration of Fe-binding organic ligands (Lt) ranged from 4.9 nM to 41 nM (average of 14.9 ± 8.4 nM, n = 34), and was always higher than the corresponding DFe (average of 7.5 ± 4.5 nM, n = 34). Conditional stability constants (log K′ Fe’L = 11.7–13.0) were similar to those previously observed in land-fast ice. Concentrations of DFe and Lt displayed similar depth profiles; their strong correlation (Spearman's ρ = 0.80, p 1). Estimates showed that pack ice would have released 0.45 μmol/m 2 /d of Lt during spring melt, 0.21 μmol/m 2 /d of which are free from Fe binding, and hence available for further complexation. Therefore, it is suggested that this excess of Fe-free ligands may play a key role in controlling the solubility of free or newly formed Fe in surface waters before the peak of primary production, outcompeting the Fe-binding organic ligands already present in seawater.

International audience; We use field observations from late spring and a one‐dimensional sea‐ice model to explore a high nutrient, high chlorophyll system in Antarctic land‐fast ice. Lack of variability in chlorophyll a concentration and organic carbon content over the 17‐day sampling period suggests a balance between macronutrient sources and biological uptake. Nitrate, nitrite, phosphate, and ammonium were measured at concentrations well above salinity‐predicted levels, indicating nutrient accumulation fueled by remineralization processes. However, silicic acid (DSi) was depleted relative to seawater and was potentially limiting. One‐dimensional physical‐biogeochemical sea‐ice model simulations at the observation site achieve extremely high algal growth and DSi uptake with a DSi half‐saturation constant used for pelagic diatoms (KSi = 3.9 μM) and are not sufficiently improved by tuning the DSi:carbon ratio or DSi remineralization rate. In contrast, diatom biomass in the bottom ice, which makes up 70% of the observed chlorophyll, is simulated using KSi an order of magnitude higher (50 μM), a value similar to that measured in a few Antarctic diatom cultures. Some sea‐ice diatoms may therefore experience limitation at relatively high ambient DSi concentrations compared to pelagic diatoms. Our study highlights the urgent need for observational data on sea‐ice algal affinity for DSi to further support this hypothesis. A lower algal growth rate increases model predictions of DSi in the upper sea ice to more accurate concentrations. The model currently does not account for the non‐diatom communities that dominate those layers, and thus, modeling diatom communities overpredicts DSi uptake in the upper ice.

Despite significant improvements in therapy, the HIV/AIDS pandemic remains an important threat to public health. Current treatments fail to eradicate HIV as proviral DNA persists in long-living cellular reservoirs, leading to viral rebound whenever treatment is discontinued. Hence, a better understanding of viral reservoir establishment and maintenance is required to develop novel strategies to destroy latently infected cells, and/or to durably silence the latent provirus in infected cells. Whereas the mechanism of integration has been well studied from a catalytic point of view, it remains unknown how integration site selection and transcription are linked. In recent years, evidence has grown that lens epithelium-derived growth factor p75 (LEDGF/p75) is the main determinant of HIV integration site selection and that the integration site affects the transcriptional state of the provirus. LEDGINs have been developed as small molecule inhibitors of the interaction between LEDGF/p75 and integrase. Recently, it was shown that LEDGIN treatment in cell culture shifts the residual integrated provirus towards the inner nuclear compartment and out of transcription units in a dose dependent manner. This LEDGIN-mediated retargeting increased the proportion of provirus with a transcriptionally silent phenotype and the residual reservoir proved refractory to reactivation in vitro. LEDGINs provide us with a research tool to study the link between integration and transcription, a quintessential question in retrovirology. LEDGIN-mediated retargeting of the residual reservoirs provides a novel potential "block-and-lock" strategy as a functional cure of HIV infection. ispartof: VIRUSES-BASEL vol:11 issue:1 ispartof: location:Switzerland status: published

This study presents the first laboratory-controlled sea-ice growth experiment conducted under trace metal clean conditions. The role played by organic matter, in the incorporation of iron (Fe) into sea ice was investigated by means of laboratory ice-growth experiments using a titanium cold-finger apparatus. Experiments were also conducted to understand the role of extracellular polymeric substances (EPS) in the enrichment of ammonium in sea ice. Sea ice was grown from several seawater solutions containing different quantities and qualities of particulate Fe (PFe), dissolved Fe (DFe) and organic matter. Sea ice and seawater were analyzed for particulate organic carbon and nitrogen, macro-nutrients, extracellular EPS, PFe and DFe, and particulate aluminium. The experiments showed that biogenic PFe is preferentially incorporated into sea ice compared to lithogenic PFe. Furthermore, sea ice grown from ultra-violet (UV) and non-UV treated seawaters exhibits contrasting incorporation rates of organic matter and Fe. Whereas the effects of UV-treatments were not always significant, we do find indications that the type or organic matter controls the enrichment of Fe in forming sea ice.. Specifically, we come to the conclusion that the incorporation of DFe is favored by the presence of organic ligands in the source solution.

This study reports concentrations of iron (Fe) and organic matter in young Antarctic pack ice and during its initial growth stages in situ. Although the importance of sea ice as an Fe reservoir for oceanic waters of the Southern Ocean has been clearly established, the processes leading to the enrichment of Fe in sea ice have yet to be investigated and quantified. We conducted two in situ sea-ice growth experiments during a winter cruise in the Weddell Sea. Our aim was to improve the understanding of the processes responsible for the accumulation of dissolved Fe (DFe) and particulate Fe (PFe) in sea ice, and of particulate organic carbon and nitrogen, dissolved organic carbon, extracellular polymeric substances, inorganic macro-nutrients (silicic acid, nitrate and nitrite, phosphate and ammonium), chlorophyll a and bacteria. Enrichment indices, calculated for natural young ice and ice newly formed in situ, indicate that during Antarctic winter all of the measured forms of particulate matter were enriched in sea ice compared to underlying seawater, and that enrichment started from the initial stages of sea-ice formation. Some dissolved material (DFe and ammonium) was also enriched in the ice but at lower enrichment indices than the particulate phase, suggesting that size is a key factor for the incorporation of impurities in sea ice. Low chlorophyll a concentrations and the fit of the macro-nutrients (with the exception of ammonium) with their theoretical dilution lines indicated low biological activity in the ice. From these and additional results we conclude that physical processes are the dominant mechanisms leading to the enrichment of DFe, PFe, organic matter and bacteria in young sea ice, and that PFe and DFe are decoupled during sea-ice formation. Our study thus provides unique quantitative insight into the initial incorporation of impurities, in particular DFe and PFe, into Antarctic sea ice., SCOPUS: ar.j, info:eu-repo/semantics/published