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Extending the carotenoid pathway to astaxanthin in plants is of scientific and industrial interest. However, expression of a microbial beta-carotene ketolase (BKT) that catalyses the formation of ketocarotenoids in transgenic plants typically results in low levels of astaxanthin. The low efficiency of BKTs in ketolating zeaxanthin to astaxanthin is proposed to be the major limitation for astaxanthin accumulation in engineered plants. To verify this hypothesis, several algal BKTs were functionally characterized using an Escherichia coli system and three BKTs were identified, with high (up to 85%), moderate (~38%), and low (~1%) conversion rate from zeaxanthin to astaxanthin from Chlamydomonas reinhardtii (CrBKT), Chlorella zofingiensis (CzBKT), and Haematococcus pluvialis (HpBKT3), respectively. Transgenic Arabidopsis thaliana expressing the CrBKT developed orange leaves which accumulated astaxanthin up to 2 mg g -1 dry weight with a 1.8-fold increase in total carotenoids. In contrast, the expression of CzBKT resulted in much lower astaxanthin content (0.24 mg g -1 dry weight), whereas HpBKT3 was unable to mediate synthesis of astaxanthin in A. thaliana. The none-native astaxanthin was found mostly in a free form integrated into the light-harvesting complexes of photosystem II in young leaves but in esterified forms in senescent leaves. The alteration of carotenoids did not affect chlorophyll content, plant growth, or development significantly. The astaxanthin-producing plants were more tolerant to high light as shown by reduced lipid peroxidation. This study advances a decisive step towards the utilization of plants for the production of high-value astaxanthin. Keywords: Arabidopsis thaliana, astaxanthin, beta-carotene ketolase, carotenoid, Haematococcus pluvialis
The process of electron-loss to the continuum (ELC) has been studied for the collision systems U28++H2 at a collision energy of 50 MeV/u, U28++N2 at 30 MeV/u, and U28++Xe at 50 MeV/u. The energy distributions of cusp electrons emitted at an angle of 0∘ with respect to the projectile beam were measured using a magnetic forward-angle electron spectrometer. For these collision systems far from equilibrium charge state, a significantly asymmetric cusp shape is observed. The experimental results are compared to calculations based on first-order perturbation theory, which predict an almost symmetric cusp shape. Some possible reasons for this discrepancy are discussed.
The genus Parandes Muir, 1925 (Cixiinae, Andini) is recorded from China for the first time with two new species, Parandes circinatus Wang & Chen sp. nov. and Parandes fuscus Wang & Chen sp. nov. Color images for the adults of the two new species and line drawings for the genitalia are provided. A key is presented to separate all species within the genus.
Numerous cell–cell and cell–matrix interactions within the bone marrow microenvironment enable the controlled lifelong self-renewal and progeny of hematopoietic stem and progenitor cells (HSPCs). On the cellular level, this highly mutual interaction is granted by cell adhesion molecules (CAMs) integrating differentiation, proliferation, and pro-survival signals from the surrounding microenvironment to the inner cell. However, cell–cell and cell–matrix interactions are also critically involved during malignant transformation of hematopoietic stem/progenitor cells. It has become increasingly apparent that leukemia-associated gene products, such as activated tyrosine kinases and fusion proteins resulting from chromosomal translocations, directly regulate the activation status of adhesion molecules, thereby directing the leukemic phenotype. These observations imply that interference with adhesion molecule function represents a promising treatment strategy to target pre-leukemic and leukemic lesions within the bone marrow niche. Focusing on myeloid leukemia, we provide a current overview of the mechanisms by which leukemogenic gene products hijack control of cellular adhesion to subsequently disturb normal hematopoiesis and promote leukemia development.
Background: Outcomes of catheter ablation of atrial fibrillation (AF) are variable and the predictors of success require further elucidation since the identification of correctable risk factors could help to optimize therapy. We aimed to assess the impact of body mass index (BMI) in the overall safety and efficacy of catheter ablation of AF, with emphasis on the use of cryoballoon ablation and novel oral anticoagulants.
Methods and Results: There were 2497 consecutive patients undergoing catheter ablation of AF in 7 European high volume centers were stratified according to BMI (normal weight <25 kg/m2, pre‐obese 25–30 kg/m2, obesity 30–35 kg/m2, and morbid obesity ≥35 kg/m2) and comparisons of procedural outcomes evaluated. Pre‐obese and obese patients presented more comorbidities (hypertension, diabetes mellitus, and sleep apnea), and had higher rates of non‐paroxysmal AF ablation procedures. The rate of atrial 12‐month arrhythmia relapse increased alongside with BMI (35.2%, 35.7%, 43.6%, and 48.0% P<0.001). During a median follow‐up of 18.8 months (interquartile range 11–28), after adjusting for all baseline differences, BMI was an independent predictor of relapse (hazard ratio=1.01 per kg/m2; 95% CI 1.01–1.02; P=0.002), adding incremental predictive value to obstructive sleep apnea. BMI was not a predictor for any of the reported complications. Using novel oral anticoagulants and cryoballoon ablation was safe and efficacy was comparable with vitamin‐K antagonists and radiofrequency ablation.
Conclusions: Obese patients present with a more adverse comorbidity profile, more advanced forms of AF, and have lower chances of being free from AF relapse after ablation. Use of novel oral anticoagulants and cryoballoon ablation may be an option in this patient group.
Sepsis is generally considered as a severe condition of inflammation that leads to lymphocyte apoptosis and multiple organ dysfunction. Hydroxysafflor yellow A (HSYA) exerts anti-inflammatory and anti-apoptotic effects in infectious diseases. However, the therapeutic effect of HSYA on polymicrobial sepsis remains unknown. This study was undertaken to investigate the therapeutic effects and the mechanisms of action of HSYA on immunosuppression in a murine model of sepsis induced by cecal ligation and puncture (CLP). NIH mice were randomly divided into four groups: control group, sham group, CLP group, and CLP+HSYA group. HSYA (120 mg/kg) was intravenously injected into experimental mice at 12 h before CLP, concurrent with CLP and 12 h after CLP. The levels of circulating inflammatory cytokines, the apoptosis of CD4+ and CD8+ T lymphocytes, and protein expression of cytochrome C (Cytc), Bax, Bcl-2, cleaved caspase-9, and cleaved caspase-3 were examined. Plasma levels of IL-6, IL-10 and TNF-alpha as well as the apoptosis of CD4+ T lymphocytes were increased compared with sham group. These changes were accompanied by increases of pro-apoptotic proteins including Cytc, Bax, cleaved caspase-9, and cleaved caspase-3 and decreases of anti-apoptotic protein Bcl-2 in CD4+ T lymphocytes from mice undergoing CLP. In contrast, we fail to observe significant effect of HSYA on the apoptosis of CD8+ T lymphocytes in CLP-treated group. Of note, HSYA treatment reversed all above changes observed in CD4+ T lymphocytes, and significantly increased the ratio of CD4+:CD8+ T lymphocytes in CLP-treated mice. In conclusion, HSYA was an effective therapeutic agent in ameliorating sepsis-induced apoptosis of CD4+ T lymphocytes probably through its anti-inflammatory and anti-apoptotic effects.
Seven new species of the genus Meta C.L. Koch, 1836 from Southwest China are described here: M. bowo sp. nov. (♂♀), M. cona sp. nov. (♂♀), M. gyirong sp. nov. (♂), M. hongyuan sp. nov. (♂♀), M. tibet sp. nov. (♂♀), M. wanglang sp. nov. (♂♀) and M. weining sp. nov. (♂♀). Detailed descriptions, photos of somatic features and copulatory organs as well as line drawings, comparisons with closely related species, and a distribution map are provided.
Using combined data from the Relativistic Heavy Ion and Large Hadron Colliders, we constrain the shear and bulk viscosities of quark-gluon plasma (QGP) at temperatures of ∼150–350 MeV. We use Bayesian inference to translate experimental and theoretical uncertainties into probabilistic constraints for the viscosities. With Bayesian model averaging we propagate an estimate of the model uncertainty generated by the transition from hydrodynamics to hadron transport in the plasma’s final evolution stage, providing the most reliable phenomenological constraints to date on the QGP viscosities.
In memory of Edward Diener: reflections on his career, contributions and the science of happiness
(2021)
Prof. Edward (Ed) Diener (1946-2021), a pioneer in positive psychology, passed away on the 27th of April 2021 at his home in Salt Lake City, Utah (Salt Lake City Tribune, 2021). As one of the most influential psychologists of the discipline, Ed Diener pushed the boundaries of our understanding of positive psychological functioning, subjective well-being, and happiness (Layous, 2020). As one of the Top 200 most cited researchers across all disciplines and fields, he will be most remembered for founding the scientific study of subjective well-being (SWB) and happiness (Bakshi, 2019). Diener developed the concept of subjective well-being by exploring the factors that influence people's life satisfaction (Diener et al., 2017a). He studied the individual causes of subjective well-being, such as close social relationships, income, meaning and purpose, personality, and societal causes, such as economic development, low corruption and crime, and a healthy environment (Diener et al., 2018). His research has discovered both universal and culture-specific causes and consequences of SWB and influenced governmental policy (Oishi et al., 1999). In respect of his memory, the purpose of this paper is threefold: (a) to reflect upon his career journey, (b) to celebrate his significant contributions to the discipline, and (c) to provide personal reflections of those who worked closely with him over the past 50 years.
The transporter associated with antigen processing (TAP) is a key component of the cellular immune system. As a member of the ATP-binding cassette (ABC) superfamily, TAP hydrolyzes ATP to energize the transport of peptides from the cytosol into the lumen of the endoplasmic reticulum. TAP is composed of TAP1 and TAP2, each containing a transmembrane domain and a nucleotide-binding domain (NBD). Here we investigated the role of the ABC signature motif (C-loop) on the functional non-equivalence of the NBDs, which contain a canonical C-loop (LSGGQ) for TAP1 and a degenerate C-loop (LAAGQ) for TAP2. Mutation of the leucine or glycine (LSGGQ) in TAP1 fully abolished peptide transport. However, TAP complexes with equivalent mutations in TAP2 still showed residual peptide transport activity. To elucidate the origin of the asymmetry of the NBDs of TAP, we further examined TAP complexes with exchanged C-loops. Strikingly, the chimera with two canonical C-loops showed the highest transport rate whereas the chimera with two degenerate C-loops had the lowest transport rate, demonstrating that the ABC signature motifs control peptide transport efficiency. All single site mutants and chimeras showed similar activities in peptide or ATP binding, implying that these mutations affect the ATPase activity of TAP. In addition, these results prove that the serine of the C-loop is not essential for TAP function but rather coordinates, together with other residues of the C-loop, the ATP hydrolysis in both nucleotide-binding sites.
The enigmatic millipede assassin bug genus Xenorhyncocoris Miller, 1938 is revised. Previously known species, X. caraboides Miller, 1938, X. princeps Miller, 1949 and X. schoenitzeri Putshkov & Bérenger, 1999, are diagnosed and photographed. A new species, X. attractivus sp. nov., is described based on male and female specimens from northeastern Borneo. The male of Xenorhyncocoris is reported for the first time, revealing the extreme sexual dimorphism present in the genus. The diagnosis of Xenorhyncocoris is extended in order to make it applicable to the new discovery, and a female-based key to species of the genus is updated. Relationships among Xenorhyncocoris and Vilius Stål, 1863, Neozirta Distant, 1919 and Schottus Distant, 1902 are briefly discussed.
Formation and segregation of cell lineages forming the heart have been studied extensively but the underlying gene regulatory networks and epigenetic changes driving cell fate transitions during early cardiogenesis are still only partially understood. Here, we comprehensively characterize mouse cardiac progenitor cells (CPCs) marked by Nkx2-5 and Isl1 expression from E7.5 to E9.5 using single-cell RNA sequencing and transposase-accessible chromatin profiling (ATAC-seq). By leveraging on cell-to-cell transcriptome and chromatin accessibility heterogeneity, we identify different previously unknown cardiac subpopulations. Reconstruction of developmental trajectories reveal that multipotent Isl1+ CPC pass through an attractor state before separating into different developmental branches, whereas extended expression of Nkx2-5 commits CPC to an unidirectional cardiomyocyte fate. Furthermore, we show that CPC fate transitions are associated with distinct open chromatin states critically depending on Isl1 and Nkx2-5. Our data provide a model of transcriptional and epigenetic regulations during cardiac progenitor cell fate decisions at single-cell resolution.
A list of authors and their affiliations appears at the end of the paper New-particle formation is a major contributor to urban smog, but how it occurs in cities is often puzzling. If the growth rates of urban particles are similar to those found in cleaner environments (1–10 nanometres per hour), then existing understanding suggests that new urban particles should be rapidly scavenged by the high concentration of pre-existing particles. Here we show, through experiments performed under atmospheric conditions in the CLOUD chamber at CERN, that below about +5 degrees Celsius, nitric acid and ammonia vapours can condense onto freshly nucleated particles as small as a few nanometres in diameter. Moreover, when it is cold enough (below −15 degrees Celsius), nitric acid and ammonia can nucleate directly through an acid–base stabilization mechanism to form ammonium nitrate particles. Given that these vapours are often one thousand times more abundant than sulfuric acid, the resulting particle growth rates can be extremely high, reaching well above 100 nanometres per hour. However, these high growth rates require the gas-particle ammonium nitrate system to be out of equilibrium in order to sustain gas-phase supersaturations. In view of the strong temperature dependence that we measure for the gas-phase supersaturations, we expect such transient conditions to occur in inhomogeneous urban settings, especially in wintertime, driven by vertical mixing and by strong local sources such as traffic. Even though rapid growth from nitric acid and ammonia condensation may last for only a few minutes, it is nonetheless fast enough to shepherd freshly nucleated particles through the smallest size range where they are most vulnerable to scavenging loss, thus greatly increasing their survival probability. We also expect nitric acid and ammonia nucleation and rapid growth to be important in the relatively clean and cold upper free troposphere, where ammonia can be convected from the continental boundary layer and nitric acid is abundant from electrical storms.
The formation of secondary particles in the atmosphere accounts for more than half of global cloud condensation nuclei. Experiments at the CERN CLOUD (Cosmics Leaving OUtdoor Droplets) chamber have underlined the importance of ions for new particle formation, but quantifying their effect in the atmosphere remains challenging. By using a novel instrument setup consisting of two nano-particle counters, one of them equipped with an ion filter, we were able to further investigate the ion-related mechanisms of new particle formation. In autumn 2015, we carried out experiments at CLOUD on four systems of different chemical compositions involving monoterpenes, sulfuric acid, nitrogen oxides, and ammonia. We measured the influence of ions on the nucleation rates under precisely controlled and atmospherically relevant conditions. Our results indicate that ions enhance the nucleation process when the charge is necessary to stabilize newly formed clusters, i.e. in conditions where neutral clusters are unstable. For charged clusters that were formed by ion-induced nucleation, we were able to measure, for the first time, their progressive neutralization due to recombination with oppositely charged ions. A large fraction of the clusters carried a charge at 1.2 nm diameter. However, depending on particle growth rates and ion concentrations, charged clusters were largely neutralized by ion–ion recombination before they grew to 2.2 nm. At this size, more than 90 % of particles were neutral. In other words, particles may originate from ion-induced nucleation, although they are neutral upon detection at diameters larger than 2.2 nm. Observations at Hyytiälä, Finland, showed lower ion concentrations and a lower contribution of ion-induced nucleation than measured at CLOUD under similar conditions. Although this can be partly explained by the observation that ion-induced fractions decrease towards lower ion concentrations, further investigations are needed to resolve the origin of the discrepancy.
We compare multiplicities as well as rapidity and transverse momentum distributions of protons, pions and kaons calculated within presently available transport approaches for heavy ion collisions around 1 AGeV. For this purpose, three reactions have been selected: Au+Au at 1 and 1.48 AGeV and Ni+Ni at 1.93 AGeV.
How does group identity affect belief formation? To address this question, we conduct a series of online experiments with a representative sample of individuals in the US. Using the setting of the 2020 US presidential election, we find evidence of intergroup preference across three distinct components of the belief formation cycle: a biased prior belief, avoid-ance of outgroup information sources, and a belief-updating process that places greater (less) weight on prior (new) information. We further find that an intervention reducing the salience of information sources decreases outgroup information avoidance by 50%. In a social learn-ing context in wave 2, we find participants place 33% more weight on ingroup than outgroup guesses. Through two waves of interventions, we identify source utility as the mechanism driving group effects in belief formation. Our analyses indicate that our observed effects are driven by groupy participants who exhibit stable and consistent intergroup preferences in both allocation decisions and belief formation across all three waves. These results suggest that policymakers could reduce the salience of group and partisan identity associated with a policy to decrease outgroup information avoidance and increase policy uptake.
Mechanisms by which specific histone modifications regulate distinct gene regulatory networks remain little understood. We investigated how H3K79me2, a modification catalyzed by DOT1L and previously considered a general transcriptional activation mark, regulates gene expression in mammalian cardiogenesis. Early embryonic cardiomyocyte ablation of Dot1l revealed that H3K79me2 does not act as a general transcriptional activator, but rather regulates highly specific gene regulatory networks at two critical cardiogenic junctures: left ventricle patterning and postnatal cardiomyocyte cell cycle withdrawal. Mechanistic analyses revealed that H3K79me2 in two distinct domains, gene bodies and regulatory elements, synergized to promote expression of genes activated by DOT1L. Surprisingly, these analyses also revealed that H3K79me2 in specific regulatory elements contributed to silencing genes usually not expressed in cardiomyocytes. As DOT1L mutants had increased numbers of postnatal mononuclear cardiomyocytes and prolonged cardiomyocyte cell cycle activity, controlled inhibition of DOT1L might be a strategy to promote cardiac regeneration post-injury.
Measurement of iodine species and sulfuric acid using bromide chemical ionization mass spectrometers
(2021)
Iodine species are important in the marine atmosphere for oxidation and new-particle formation. Understanding iodine chemistry and iodine new-particle formation requires high time resolution, high sensitivity, and simultaneous measurements of many iodine species. Here, we describe the application of a bromide chemical ionization mass spectrometer (Br-CIMS) to this task. During the iodine oxidation experiments in the Cosmics Leaving OUtdoor Droplets (CLOUD) chamber, we have measured gas-phase iodine species and sulfuric acid using two Br-CIMS, one coupled to a Multi-scheme chemical IONization inlet (Br-MION-CIMS) and the other to a Filter Inlet for Gasses and AEROsols inlet (Br-FIGAERO-CIMS). From offline calibrations and intercomparisons with other instruments, we have quantified the sensitivities of the Br-MION-CIMS to HOI, I2, and H2SO4 and obtained detection limits of 5.8 × 106, 3.8 × 105, and 2.0 × 105 molec. cm−3, respectively, for a 2 min integration time. From binding energy calculations, we estimate the detection limit for HIO3 to be 1.2 × 105 molec. cm−3, based on an assumption of maximum sensitivity. Detection limits in the Br-FIGAERO-CIMS are around 1 order of magnitude higher than those in the Br-MION-CIMS; for example, the detection limits for HOI and HIO3 are 3.3 × 107 and 5.1 × 106 molec. cm−3, respectively. Our comparisons of the performance of the MION inlet and the FIGAERO inlet show that bromide chemical ionization mass spectrometers using either atmospheric pressure or reduced pressure interfaces are well-matched to measuring iodine species and sulfuric acid in marine environments.
Using apoE phenotyping by immunoblotting and apoE genotyping we identified four heterozygous carriers of a rare apolipoprotein (apo) E2 variant, apoE2 (Arg136 → Cys). ApoE2 (Arg136 → Cys) was not distinct from apoE2 (Arg158 → Cys) by phenotyping, but produced a unique pattern of bands on CfoI restriction typing of a 244 bp apoE gene fragment. Two of the four apoE2 (Arg136 → Cys)/3 heterozygotes had elevated triglycerides, two were normolipidemic. The composition of very low density lipoproteins (VLDL) was normal in each of the four apoE2 (Arg136 → Cys) carriers, regardless of the triglyceride concentrations. None of the apoE2 (Arg136 → Cys) carriers displayed a broad β-band and none revealed β-migrating particles in the VLDL. The two hypertriglyceridemic carriers of apoE2 (Arg136 → Cys) were, therefore, classified as having type IV rather than type III hyperlipoproteinemia. LDL receptor binding activities were studied using recombinant apoE loaded to dimyristoylphosphatidylcholine (DMPC) vesicles and to VLDL and from an apoE-deficient individual. LDL receptor binding of apoE2 (Arg136 → Cys) was 14% of apoE3 and was thus higher than that of apoE2 (Arg158 → Cys). Both apoE2 (Arg136 → Cys) and apoE2 (Arg158 → Cys) displayed substantial heparin binding (61 and 53% of apoE3, respectively). As the dominant apoE variants known so far are characterized by more pronounced reductions of heparin binding, we suggest that apoE2 (Arg136 → Cys) is not associated with dominant expression of type III hyperlipoproteinemia. These findings lend support to the concept that apoE variants predisposing to dominant type III hyperlipoproteinemia differ from recessive mutations by a more severe defect in heparin binding.—März, W., M. M. Hoffmann, H. Scharnagl, E. Fisher, M. Chen, M. Nauck, G. Feussner, and H. Wieland. Apolipoprotein E2 (Arg136 → Cys) mutation in the receptor binding domain of apoE is not associated with dominant type III hyperlipoproteinemia.
The ABC transporter Mdl1p, a structural and functional homologue of the transporter associated with antigen processing (TAP) plays an important role in intracellular peptide transport from the mitochondrial matrix of Saccharomyces cerevisiae. To characterize the ATP hydrolysis cycle of Mdl1p, the nucleotide-binding domain (NBD) was overexpressed in Escherichia coli and purified to homogeneity. The isolated NBD was active in ATP binding and hydrolysis with a turnover of 25 ATP per minute and a Km of 0.6 mm and did not show cooperativity in ATPase activity. However, the ATPase activity was non-linearly dependent on protein concentration (Hill coefficient of 1.7), indicating that the functional state is a dimer. Dimeric catalytic transition states could be trapped either by incubation with orthovanadate or beryllium fluoride, or by mutagenesis of the NBD. The nucleotide composition of trapped intermediate states was determined using [alpha-32P]ATP and [gamma-32P]ATP. Three different dimeric intermediate states were isolated, containing either two ATPs, one ATP and one ADP, or two ADPs. Based on these experiments, it was shown that: (i) ATP binding to two NBDs induces dimerization, (ii) in all isolated dimeric states, two nucleotides are present, (iii) phosphate can dissociate from the dimer, (iv) both nucleotides are hydrolyzed, and (v) hydrolysis occurs in a sequential mode. Based on these data, we propose a processive-clamp model for the catalytic cycle in which association and dissociation of the NBDs depends on the status of bound nucleotides.