New Insights Into Sunflower (Helianthus annuus L.) FatA and FatB Thioesterases, Their Regulation, Structure and Distribution

Sunflower seeds (Helianthus annuus L.) accumulate large quantities of triacylglycerols (TAG) between 12 and 28 days after flowering (DAF). This is the period of maximal acyl-acyl carrier protein (acyl-ACP) thioesterase activity in vitro, the enzymes that terminate the process of de novo fatty acid synthesis by catalyzing the hydrolysis of the acyl-ACPs synthesized by fatty acid synthase. Fatty acid thioesterases can be classified into two families with distinct substrate specificities, namely FatA and FatB. Here, some new aspects of these enzymes have been studied, assessing how both enzymes contribute to the acyl composition of sunflower oil, not least through the changes in their expression during the process of seed filling. Moreover, the binding pockets of these enzymes were modeled based on new data from plant thioesterases, revealing important differences in their volume and geometry. Finally, the subcellular location of the two enzymes was evaluated and while both possess an N-terminal plastid transit peptide, only in FatB contains a hydrophobic sequence that could potentially serve as a transmembrane domain. Indeed, using in vivo imaging and organelle fractionation, H. annuus thioesterases, HaFatA and HaFatB, appear to be differentially localized in the plastid stroma and membrane envelope, respectively. The divergent roles fulfilled by HaFatA and HaFatB in oil biosynthesis are discussed in the light of our data.España MINECO y FEDER Projects AGL2014- 53537-R y AGL2017-83449-

Fat-free/lean body mass in children with insulin resistance or metabolic syndrome: a systematic review and meta-analysis

Background: Lean / Fat Free Body Mass (LBM) is metabolically involved in active processes such as resting energy expenditure, glucose uptake, and myokine secretion. Nonetheless, its association with insulin sensitivity / resistance / glucose tolerance and metabolic syndrome remains unclear in childhood. Methods: The current investigation aimed to examine the differences in fat-free mass /lean body mass according to the presence of insulin sensitivity/insulin resistance/glucose tolerance/metabolic syndrome in children. A systematic search was carried out in Medline/PubMed, Embase, Scopus, Web of Science, and SciELO, covering the period from each database''s respective start to 21 June 2021. Two researchers evaluated 7111 studies according to the inclusion criteria: original human studies, written in English or Spanish, evaluating fat-free mass/lean body mass in children and adolescents including both with and without insulin sensitivity/insulin resistance /glucose tolerance and metabolic syndrome and reported the differences between them in terms of fat free mass/lean body mass. The results of the studies were combined with insulin sensitivity, insulin, resistance, glucose tolerance and metabolic syndrome. The standardized mean difference (SMD) in each study was calculated and combined using the random-effects model. Heterogeneity between studies was tested using the index of heterogeneity (I-2), leave-one-out sensitivity analyses were performed, and publication bias was assessed using the Egger and Begg tests. Results: Finally, 15 studies which compared groups defined according to different glucose homeostasis criteria or metabolic syndrome out of 103 eligible studies were included in this systematic review and 12 studies in the meta-analysis. Meta-analysis showed lower fat-free mass/lean body mass percentage in participants with insulin resistance/glucose tolerance/metabolic syndrome (SMD -0.47; 95% CI, - 0.62 to - 0.32) while in mass units (kg), higher values were found in the same group (SMD, 1.01; 95% CI, 0.43 to 1.60). Conclusions: Our results identified lower values of fat-free mass/lean body mass (%) in children and adolescents with insulin resistance/glucose tolerance/metabolic syndrome and higher values of fat-free mass/lean body mass when these are expressed in kg. The evidence of the impact of lean mass on children''s glucose homeostasis or metabolic syndrome is limited, so future studies research should focus on explaining the effect of fat-free mass/lean body mass on different metabolic outcomes. Moreover, it may be interesting to evaluate the quality (muscle density) or functional (muscle strength) outcomes in addition to both absolute (kg) and relative (%) values in future studies

Clustering COVID-19 ARDS patients through the first days of ICU admission. An analysis of the CIBERESUCICOVID Cohort

Background Acute respiratory distress syndrome (ARDS) can be classified into sub-phenotypes according to different inflammatory/clinical status. Prognostic enrichment was achieved by grouping patients into hypoinflammatory or hyperinflammatory sub-phenotypes, even though the time of analysis may change the classification according to treatment response or disease evolution. We aimed to evaluate when patients can be clustered in more than 1 group, and how they may change the clustering of patients using data of baseline or day 3, and the prognosis of patients according to their evolution by changing or not the cluster.Methods Multicenter, observational prospective, and retrospective study of patients admitted due to ARDS related to COVID-19 infection in Spain. Patients were grouped according to a clustering mixed-type data algorithm (k-prototypes) using continuous and categorical readily available variables at baseline and day 3.Results Of 6205 patients, 3743 (60%) were included in the study. According to silhouette analysis, patients were grouped in two clusters. At baseline, 1402 (37%) patients were included in cluster 1 and 2341(63%) in cluster 2. On day 3, 1557(42%) patients were included in cluster 1 and 2086 (57%) in cluster 2. The patients included in cluster 2 were older and more frequently hypertensive and had a higher prevalence of shock, organ dysfunction, inflammatory biomarkers, and worst respiratory indexes at both time points. The 90-day mortality was higher in cluster 2 at both clustering processes (43.8% [n = 1025] versus 27.3% [n = 383] at baseline, and 49% [n = 1023] versus 20.6% [n = 321] on day 3). Four hundred and fifty-eight (33%) patients clustered in the first group were clustered in the second group on day 3. In contrast, 638 (27%) patients clustered in the second group were clustered in the first group on day 3.Conclusions During the first days, patients can be clustered into two groups and the process of clustering patients may change as they continue to evolve. This means that despite a vast majority of patients remaining in the same cluster, a minority reaching 33% of patients analyzed may be re-categorized into different clusters based on their progress. Such changes can significantly impact their prognosis

Dynamics of oil and fatty acid accumulation during seed development in historical soybean varieties

Soybean seed oil concentration and fatty acid (FA) composition are relevant traits defining oil quality and economic value for industry. In spite of the importance of FA composition for soybean value, a detailed description of FA profile and accumulation during seed filling in contrasting soybean varieties and management conditions is currently lacking. This study aims to: i) evaluate whether genetic progress in soybean yield indirectly affected FA profile, ii) assess the influence of N fertilization on FA profile, iii) characterize the temporal dynamics of FA accumulation during seed filling, and iv) evaluate the relative contribution of FA accumulation rate vs. duration on final FA seed content. Seven soybean varieties released between 1980 and 2013 were field grown under control (0 kg N ha−1) and fertilized (670 kg N ha−1 added) treatments. In addition to seed yield, total seed oil and FA contents during seed filling were recorded by sampling seeds from the beginning of seed formation to maturity. Genetic progress was evident in seed yield with an increase of 31.3 kg ha year−1. Total oil concentration (g oil kg−1) slightly decreased across year of release for the control. Fatty acid concentration (g FA 100 g oil−1) profile was not associated with year of release but affected by varieties. Variation in total oil and FA contents (mg seed−1) across varieties and N treatments was mostly associated to longer filling but was also affected by accumulation rates. Interestingly, individual FA concentration at maturity was independent from FA content. Our results indicate past breeding efforts have not modified soybean FA profile. The fact that changes in FA contents were not translated in changes in FA concentration indicates that seed control of FA profile is narrow. Disentangling the physiological mechanism associated with FA homeostasis warrants further examination.Fil: Tamagno, Santiago. Kansas State University; Estados UnidosFil: Aznar Moreno, Jose A.. Kansas State University; Estados Unidos. Universidad Politécnica de Madrid; EspañaFil: Durrett, Timothy P.. Kansas State University; Estados UnidosFil: Vara Prasad, P.V.. Kansas State University; Estados UnidosFil: Rotundo, José Luis. Corteva Agriscience; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; ArgentinaFil: Ciampitti, Ignacio Antonio. Kansas State University; Estados Unido

Functional Nitrogenase Cofactor Maturase NifB in Mitochondria and Chloroplasts of Nicotiana benthamiana

13 Pág. Centro de Biotecnología y Genómica de Plantas (CBGP)Engineering plants to synthesize nitrogenase and assimilate atmospheric N2 will reduce crop dependency on industrial N fertilizers. This technology can be achieved by expressing prokaryotic nitrogen fixation gene products for the assembly of a functional nitrogenase in plants. NifB is a critical nitrogenase component since it catalyzes the first committed step in the biosynthesis of all types of nitrogenase active-site cofactors. Here, we used a library of 30 distinct nifB sequences originating from different phyla and ecological niches to restore diazotrophic growth of an Azotobacter vinelandii nifB mutant. Twenty of these variants rescued the nifB mutant phenotype despite their phylogenetic distance to A. vinelandii. Because multiple protein interactions are required in the iron-molybdenum cofactor (FeMo-co) biosynthetic pathway, the maturation of nitrogenase in a heterologous host can be divided in independent modules containing interacting proteins that function together to produce a specific intermediate. Therefore, nifB functional modules composed of a nifB variant, together with the A. vinelandii NifS and NifU proteins (for biosynthesis of NifB [Fe4S4] clusters) and the FdxN ferredoxin (for NifB function), were expressed in Nicotiana benthamiana chloroplasts and mitochondria. Three archaeal NifB proteins accumulated at high levels in soluble fractions of chloroplasts (Methanosarcina acetivorans and Methanocaldococcus infernus) or mitochondria (M. infernus and Methanothermobacter thermautotrophicus). These NifB proteins were shown to accept [Fe4S4] clusters from NifU and were functional in FeMo-co synthesis in vitro. The accumulation of significant levels of soluble and functional NifB proteins in chloroplasts and mitochondria is critical to engineering biological nitrogen fixation in plants. IMPORTANCE Biological nitrogen fixation is the conversion of inert atmospheric dinitrogen gas into nitrogen-reactive ammonia, a reaction catalyzed by the nitrogenase enzyme of diazotrophic bacteria and archaea. Because plants cannot fix their own nitrogen, introducing functional nitrogenase in cereals and other crop plants would reduce our strong dependency on N fertilizers. NifB is required for the biosynthesis of the active site cofactors of all nitrogenases, which arguably makes it the most important protein in global nitrogen fixation. NifB functionality is therefore a requisite to engineer a plant nitrogenase. The expression of nifB genes from a wide range of prokaryotes into the model diazotroph Azotobacter vinelandii shows a surprising level of genetic complementation suggestive of plasticity in the nitrogenase biosynthetic pathway. In addition, we obtained NifB proteins from both mitochondria and chloroplasts of tobacco that are functional in vitro after reconstitution by providing [Fe4S4] clusters from NifU, paving the way to nitrogenase cofactor biosynthesis in plants.This study was supported, in whole or in part, by the Bill & Melinda Gates Foundation (OPP1143172 and INV 005889). Under the grant conditions of the Foundation, a Creative Commons Attribution 4.0 Generic License has already been assigned to the Author Accepted Manuscript version that might arise from this submission. X.J. was supported by a doctoral fellowship from Universidad Politécnica de MadridPeer reviewe

Rapid decrease in titer and breadth of neutralizing anti-HCV antibodies in HIV/HCV-coinfected patients who achieved SVR

The main targets for neutralizing anti-hepatitis C virus (HCV) antibodies (HCV-nAbs) are the E1 and E2 envelope glycoproteins. We have studied the characteristics of HCV-nAbs through a retrospective study involving 29 HIV/HCV-coinfected patients who achieved sustained virological response (SVR) with peg-IFNα + ribavirin anti-HCV therapy. Plasma samples at baseline and week 24 after SVR were used to perform neutralization assays against five JFH1-based HCV recombinant viruses coding for E1 and E2 from genotypes 1a (H77), 1b (J4), 2a (JFH1), 3a (S52) and 4a (ED43). At baseline, the majority of plasma samples neutralized 1a, 1b, 2a, and 4a, but not 3a, genotypes. Twenty-four weeks following SVR, most neutralizing titers declined substantially. Furthermore, titers against 3a and 2a were not detected in many patients. Plasma samples with high HCV-nAb titers neutralized all genotypes, and the highest titers at the starting point correlated with the highest titers at week 24 after SVR. In conclusion, high titers of broad-spectrum HCV-nAbs were detected in HIV/HCV-coinfected individuals, however, those titers declined soon after SVR