Triacylglycerol synthesis by PDAT1 in the absence of DGAT1 activity is dependent on re-acylation of LPC by LPCAT2

<p>Abstract</p> <p>Background</p> <p>The <it>Arabidopsis thaliana dgat1 </it>mutant, <it>AS11</it>, has an oil content which is decreased by 30%, and a strongly increased ratio of 18:3/20:1, compared to wild type. Despite lacking a functional DGAT1, <it>AS11 </it>still manages to make 70% of WT seed oil levels. Recently, it was demonstrated that in the absence of <it>DGAT1</it>, <it>PDAT1 </it>was essential for normal seed development, and is a dominant determinant in <it>Arabidopsis </it>TAG biosynthesis.</p> <p>Methods</p> <p>Biochemical, metabolic and gene expression studies combined with genetic crossing of selected <it>Arabidopsis </it>mutants have been carried out to demonstrate the contribution of <it>Arabidopsis </it>PDAT1 and LPCAT2 in the absence of DGAT1 activity.</p> <p>Results</p> <p>Through microarray and RT-PCR gene expression analyses of <it>AS11 </it>vs. WT mid-developing siliques, we observed consistent trends between the two methods. <it>FAD2 </it>and <it>FAD3 </it>were up-regulated and <it>FAE1 </it>down-regulated, consistent with the <it>AS11 </it>acyl phenotype. <it>PDAT1 </it>expression was up-regulated by <it>ca </it>65% while <it>PDAT2 </it>expression was up-regulated only 15%, reinforcing the dominant role of <it>PDAT1 </it>in <it>AS11 </it>TAG biosynthesis. The expression of <it>LPCAT2 </it>was up-regulated by 50-75%, while <it>LPCAT1 </it>expression was not significantly affected. <it>In vitro </it>LPCAT activity was enhanced by 75-125% in microsomal protein preparations from mid-developing <it>AS11 </it>seed <it>vs </it>WT. Co-incident homozygous knockout lines of <it>dgat1</it>/<it>lpcat2 </it>exhibited severe penalties on TAG biosynthesis, delayed plant development and seed set, even with a functional PDAT1; the double mutant <it>dgat1/lpcat1 </it>showed only marginally lower oil content than <it>AS11</it>.</p> <p>Conclusions</p> <p>Collectively, the data strongly support that in <it>AS11 </it>it is <it>LPCAT2 </it>up-regulation which is primarily responsible for assisting in PDAT1-catalyzed TAG biosynthesis, maintaining a supply of PC as co-substrate to transfer <it>sn</it>-2 moieties to the <it>sn</it>-3 position of the enlarged <it>AS11 </it>DAG pool.</p

HIV-infected sex workers with beneficial HLA-variants are potential hubs for selection of HIV-1 recombinants that may affect disease progression

Cytotoxic T lymphocyte (CTL) responses against the HIV Gag protein are associated with lowering viremia; however, immune control is undermined by viral escape mutations. The rapid viral mutation rate is a key factor, but recombination may also contribute. We hypothesized that CTL responses drive the outgrowth of unique intra-patient HIV-recombinants (URFs) and examined gag sequences from a Kenyan sex worker cohort. We determined whether patients with HLA variants associated with effective CTL responses (beneficial HLA variants) were more likely to carry URFs and, if so, examined whether they progressed more rapidly than patients with beneficial HLA-variants who did not carry URFs. Women with beneficial HLA-variants (12/52) were more likely to carry URFs than those without beneficial HLA variants (3/61) (p &lt; 0.0055; odds ratio = 5.7). Beneficial HLA variants were primarily found in slow/standard progressors in the URF group, whereas they predominated in long-term non-progressors/survivors in the remaining cohort (p = 0.0377). The URFs may sometimes spread and become circulating recombinant forms (CRFs) of HIV and local CRF fragments were over-represented in the URF sequences (p &lt; 0.0001). Collectively, our results suggest that CTL-responses associated with beneficial HLA variants likely drive the outgrowth of URFs that might reduce the positive effect of these CTL responses on disease progression

Comparing the quantity and quality of randomized placebo-controlled trials of antibiotics for acute respiratory, urinary, and skin and soft tissue infections:a scoping review

BACKGROUND: The management of acute respiratory infections (ARIs), urinary tract infections (UTIs), and skin and soft tissue infections (SSTIs) should be guided by high quality evidence.AIM: To compare the quantity and quality of randomised placebo-controlled trials of antibiotics for ARIs, UTIs, and SSTIs.DESIGN &amp; SETTING: A scoping review of the literature was performed using comprehensive search strategies.METHOD: PubMed and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched for published studies from inception until 17 April 2019. Randomised controlled trials (RCTs) that compared participants in primary care or in the community who had uncomplicated acute ARI, UTI, or studies, and were randomised to antibiotic or placebo (or no active treatment), were eligible for inclusion. Two groups of researchers independently screened articles for inclusion, extracted data, and assessed the quality of included studies.RESULTS: A total of 108 eligible studies were identified: 80 on ARI, eight on UTI, and 20 on SSTI. The quality of studies varied with unclear risk of bias (RoB) prevalent in many domains. There was a gradual improvement in the quality of trials investigating ARIs over time, which could not be assessed in SSTI and UTI studies.CONCLUSION: This review highlights a sparsity of trials assessing the effectiveness of antibiotics in people with UTIs and SSTIs, compared to trials targeting ARIs. This gap in the evidence needs to be addressed by conducting further high quality trials on the effects of antibiotics in patients with UTI and SSTI.</p

Be prepared: communism and the politics of scouting in 1950s Britain

This article examines the exposure, and in some cases dismissal, of Boy Scouts who belonged or sympathised with the Young Communist League in Britain during the early 1950s. A focus on the rationale and repercussions of the organisation's approach and attitudes towards ‘Red Scouts’ found within their ‘ranks’ extends our understanding of youth movements and their often complex and conflicting ideological foundations. In particular, the post-World War Two period presented significant challenges to these spaces of youth work in terms of broader social and political change in Britain. An analysis of the politics of scouting in relation to Red Scouts questions not only the assertion that British McCarthyism was ‘silent’, but also brings young people firmly into focus as part of a more everyday politics of communism in British society