Clonal Relapse Dynamics in Acute Myeloid Leukemia Following Allogeneic Hematopoietic Cell Transplantation.

Patients with acute myeloid leukemia (AML) who experience relapse following allogeneic hematopoietic cell transplantation (alloHCT) face unfavorable outcomes regardless of the chosen relapse treatment. Early detection of relapse at the molecular level by measurable residual disease (MRD) assessment enables timely intervention, which may prevent hematological recurrence of the disease. It remains unclear whether molecular MRD assessment can detect MRD before impending relapse and, if so, how long in advance. This study elucidates the molecular architecture and kinetics preceding AML relapse by utilizing error-corrected next-generation sequencing (NGS) in 74 AML patients relapsing after alloHCT evaluating 140 samples from peripheral blood collected 0.6 to 14 months before relapse. At least one MRD marker became detectable in 10%, 38%, and 64% of patients at 6, 3, and 1 months prior to relapse, respectively. By translating these proportions into monitoring intervals, 38% of relapses would have been detected through MRD monitoring every 3 months, while 64% of relapses would have been detected with monthly intervals. The relapse kinetics after alloHCT are influenced by the functional class of mutations and their stability during molecular progression. Notably, mutations in epigenetic modifier genes exhibited a higher prevalence of MRD positivity and greater stability before relapse, while mutations in signaling genes demonstrated a shorter lead-time to relapse. Both DTA and non-DTA mutations displayed similar relapse kinetics during the follow-up period after alloHCT. Our study sets a framework for MRD monitoring after alloHCT by NGS supporting monthly monitoring from peripheral blood using all variants that are known from diagnosis.

Grapevine leaf physiology and morphological characteristics to elevated CO2 in the VineyardFACE (Free air Carbon dioxide Enrichment) experiment.

Atmospheric carbon dioxide (CO2) concentration has continuously increased since pre-industrial times and has currently reached an average growth rate of 2.3 ppm per year. For the majority of plant species elevated CO2 (eCO2) improves photosynthesis and thus plant biomass production. To investigate the effects of eCO2 on leaf physiology and morphological leaf characteristics two Vitis vinifera L. cultivars, Riesling and Cabernet Sauvignon, grown in the VineyardFACE (Free Air Carbon dioxide Enrichment) system were used. The VineyardFACE is located at Geisenheim, Rheingau comparing future atmospheric CO2-concentrations (eCO2, predicted for the mid-21st century) with current ambient CO2-conditions (aCO2). Experiments were operated under rain-fed conditions for two consecutive years (2015 and 2016). For both varieties and CO2 treatments, leaf gas exchange measurements were performed as well as measures of epidermal flavonoid (Flav) and leaf chlorophyll (Chl) indices by using a portable leaf clip. Furthermore, leaves were sampled for spectrophotometric analysis of the leaf pigments chlorophyll a (Chl a), chlorophyll b (Chl b) and carotenoid (Car). Additionally, leaf cross-sections were produced as permanent preparations to investigate morphological characteristics of the leaf structure. Both cultivars did not differ in leaf chlorophyll meter readings or leaf pigments between the two CO2 treatments while net assimilation was highly stimulated under elevated CO2 for both seasons. Differences found in leaf cross-sections were detected in palisade parenchyma and epidermal thickness of Cabernet Sauvignon under eCO2, whereas Riesling net assimilation increased by 40% under a 20% CO2 enrichment while remaining unaffected in different leaf layer thickness. The observed results within grapevine leaf tissues provide insights to seasonal adaptation strategies of grapevines under elevated CO2 concentrations predicted in future.

Implantable Sensors Based on Gold Nanoparticles for Continuous Long-Term Concentration Monitoring in the Body.

Implantable sensors continuously transmit information on vital values or biomarker concentrations in bodily fluids, enabling physicians to survey disease progression and monitor therapeutic success. However, currently available technologies still face difficulties with long-term operation and transferability to different analytes. We show the potential of a generalizable platform based on gold nanoparticles embedded in a hydrogel for long-term implanted biosensing. Using optical imaging and an intelligent sensor/reference-design, we assess the tissue concentration of kanamycin in anesthetized rats by interrogating our implanted sensor noninvasively through the skin. Combining a tissue-integrating matrix, robust aptamer receptors, and photostable gold nanoparticles, our technology has strong potential to extend the lifetime of implanted sensors. Because of the easy adaptability of gold nanoparticles toward different analytes, our concept will find versatile applications in personalized medicine or pharmaceutical development.

Reaction mechanism of the farnesyl pyrophosphate C-methyltransferase towards the biosynthesis of pre-sodorifen pyrophosphate by Serratia plymuthica 4Rx13.

Classical terpenoid biosynthesis involves the cyclization of the linear prenyl pyrophosphate precursors geranyl-, farnesyl-, or geranylgeranyl pyrophosphate (GPP, FPP, GGPP) and their isomers, to produce a huge number of natural compounds. Recently, it was shown for the first time that the biosynthesis of the unique homo-sesquiterpene sodorifen by Serratia plymuthica 4Rx13 involves a methylated and cyclized intermediate as the substrate of the sodorifen synthase. To further support the proposed biosynthetic pathway, we now identified the cyclic prenyl pyrophosphate intermediate pre-sodorifen pyrophosphate (PSPP). Its absolute configuration (6R,7S,9S) was determined by comparison of calculated and experimental CD-spectra of its hydrolysis product and matches with those predicted by semi-empirical quantum calculations of the reaction mechanism. In silico modeling of the reaction mechanism of the FPP C-methyltransferase (FPPMT) revealed a SN2 mechanism for the methyl transfer followed by a cyclization cascade. The cyclization of FPP to PSPP is guided by a catalytic dyad of H191 and Y39 and involves an unprecedented cyclopropyl intermediate. W46, W306, F56, and L239 form the hydrophobic binding pocket and E42 and H45 complex a magnesium cation that interacts with the diphosphate moiety of FPP. Six additional amino acids turned out to be essential for product formation and the importance of these amino acids was subsequently confirmed by site-directed mutagenesis. Our results reveal the reaction mechanism involved in methyltransferase-catalyzed cyclization and demonstrate that this coupling of C-methylation and cyclization of FPP by the FPPMT represents an alternative route of terpene biosynthesis that could increase the terpenoid diversity and structural space.

Investigation of electron transfer between single plasmon and graphene by dark field spectroscopy.

We investigated the electron transfer time between single plasmonic gold nanoparticles and graphene with our home-build spectral imaging dark-field microscope. The process of electron transfer is supposed to be shuttling of hot electrons on the nanoparticle-graphene interface, resulting in a slight broadening of the scattering spectrum. For detecting the minor spectrum broadening, we firstly characterized our setup systematically and then calibrated its intrinsic error. We found the mechanism of a common but normally neglected setup error, scattering spectrum broadening, which is caused by the bandwidth of the incident light and could exist in most fast dark-field microscopy setups. We corrected the linewidth of plasmon scattering spectra theoretically by both numerical and analytical solution, and then realized it experimentally by tuning the bandwidth of the incident light. After calibration, we revisited scattering spectra of 700 small aspect ratio nanorods on glass and monolayer graphene revealing a typical 14.3 meV linewidth broadening. Furthermore, we measured four other kinds of gold nanoparticles on glass, mono- and bilayer graphene for deeper understanding of the electron transfer. A common linewidth broadening is found for each kind of particle agreeing well with previous theory. However, an unconventional linewidth narrowing is also discovered for big particles whose resonance wavelength is close to the near infrared region. It implies a competitive mechanism in the electron transfer process which could not only increase the damping of small particles, causing a linewidth broadening, but also simplify the electric field pattern for big particles, leading to a linewidth narrowing, according to our Mie theory simulation.

Momentum Distribution of Electrons Emitted from Resonantly Excited Individual Gold Nanorods.

Electron emission by femtosecond laser pulses from individual Au nanorods is studied with a time-of-flight momentum resolving photoemission electron microscope (ToF k-PEEM). The Au nanorods adhere to a transparent indium-tin oxide substrate, allowing for illumination from the rear side at normal incidence. Localized plasmon polaritons are resonantly excited at 800 nm with 100 fs long pulses. The momentum distribution of emitted electrons reveals two distinct emission mechanisms: a coherent multiphoton photoemission process from the optically heated electron gas leads to an isotropic emission distribution. In contrast, an additional emission process resulting from the optical field enhancement at both ends of the nanorod leads to a strongly directional emission parallel to the nanorod's long axis. The relative intensity of both contributions can be controlled by the peak intensity of the incident light.

Software compensation in particle flow reconstruction.

The particle flow approach to calorimetry benefits from highly granular calorimeters and sophisticated software algorithms in order to reconstruct and identify individual particles in complex event topologies. The high spatial granularity, together with analogue energy information, can be further exploited in software compensation. In this approach, the local energy density is used to discriminate electromagnetic and purely hadronic sub-showers within hadron showers in the detector to improve the energy resolution for single particles by correcting for the intrinsic non-compensation of the calorimeter system. This improvement in the single particle energy resolution also results in a better overall jet energy resolution by improving the energy measurement of identified neutral hadrons and improvements in the pattern recognition stage by a more accurate matching of calorimeter energies to tracker measurements. This paper describes the software compensation technique and its implementation in particle flow reconstruction with the Pandora Particle Flow Algorithm (PandoraPFA). The impact of software compensation on the choice of optimal transverse granularity for the analogue hadronic calorimeter option of the International Large Detector (ILD) concept is also discussed.

Subtle deficits of cognitive theory of mind in unaffected first-degree relatives of schizophrenia patients.

Alterations of theory of mind (ToM) and empathy were implicated in the formation of psychotic experiences, and deficits in psychosocial functioning of schizophrenia patients. Inspired by concepts of neurocognitive endophenotypes, the existence of a distinct, potentially neurobiologically based social-cognitive vulnerability marker for schizophrenia is a matter of ongoing debate. The fact that previous research on social-cognitive deficits in individuals at risk yielded contradictory results may partly be due to an insufficient differentiation between qualitative aspects of ToM. Thirty-four unaffected first-degree relatives of schizophrenia patients (21 parents, 8 siblings, 5 children; f/m: 30/4; mean age: 48.1 ± 12.7 years) and 34 controls subjects (f/m: 25/9; mean age: 45.9 ± 10.9 years) completed the 'Movie for the Assessment of Social Cognition'-a video-based ToM test-and an empathy questionnaire (Interpersonal Reactivity Index, IRI). Outcome parameters comprised (1) 'cognitive' versus 'emotional' ToM, (2) error counts representing 'undermentalizing' versus 'overmentalizing', (3) empathic abilities and (4) non-social neurocognition. MANCOVA showed impairments in cognitive but not emotional ToM in the relatives' group, when age, gender and neurocognition were controlled for. Relatives showed elevated error counts for 'undermentalizing' but not for 'overmentalizing'. No alterations were detected in self-rated dimensions of empathy. Of all measures of ToM and empathy, only the IRI subscale 'fantasy' was associated with measures of psychotic risk, i.e. a history of subclinical delusional ideation. The present study confirmed subtle deficits in cognitive, but not emotional ToM in first-degree relatives of schizophrenia patients, which were not explained by global cognitive deficits. Findings corroborate the assumption of distinct social-cognitive abilities as an intermediate phenotype for schizophrenia.

The dynamics of practice effects in an optotype acuity task.

BACKGROUND: Practice-related improvements of performance are common in many areas of visual processing. There is preliminary evidence that this is also the case for standard optotype acuity tasks. The present study was designed to confirm and quantify the effect of practice under different feedback conditions and to track the dynamics of practice over several sessions. METHODS: Subjects completed a total of 56 runs of a computer-based acuity test with randomly oriented Landolt C optotypes, split evenly over four sessions at intervals of 1 week. Half of the subjects received feedback indicating the correct response. RESULTS: Over the course of the sessions, the test outcomes increased significantly by 0.11 logMAR with feedback and by 0.055 logMAR without feedback. In addition to an increase in acuity over the first few runs of the first session, a major part of the practice effect with feedback occurred not during a session, but in between the first and the second session. Without feedback, the increase in acuity occurred mainly within the first half of the first session. CONCLUSIONS: Feedback has a drastic effect on the magnitude and dynamics of the practice effect, which is not explained by simple familiarization with the test procedure. If feedback is not given, practice effects can be neglected in most clinical routine applications even when many test repetitions are performed. However, they may become relevant on a group level in clinical studies without an appropriate control.

Large impact of the apoplast on somatic embryogenesis in Cyclamen persicum offers possibilities for improved developmental control in vitro.

BACKGROUND: Clonal propagation is highly desired especially for valuable horticultural crops. The method with the potentially highest multiplication rate is regeneration via somatic embryogenesis. However, this mode of propagation is often hampered by the occurrence of developmental aberrations and non-embryogenic callus. Therefore, the developmental process of somatic embryogenesis was analysed in the ornamental crop Cyclamen persicum by expression profiling, comparing different developmental stages of embryogenic cell cultures, zygotic vs. somatic embryos and embryogenic vs. non-embryogenic cell cultures. RESULTS: The analysis was based on a cDNA microarray representing 1,216 transcripts and was exemplarily validated by realtime PCR. For this purpose relative transcript abundances of homologues of a putative receptor kinase, two different glutathione S-transferases (GST), a xyloglucan endotransglycosylase (XET) and a peroxidase (POX) were quantitatively measured by realtime PCR for three different comparisons. In total, 417 genes were found to be differentially expressed. Gene Ontology annotation revealed that transcripts coding for enzymes that are active in the extracellular compartment (apoplast) were significantly overrepresented in several comparisons. The expression profiling results are underpinned by thorough histological analyses of somatic and zygotic embryos. CONCLUSIONS: The putative underlying physiological processes are discussed and hypotheses on improvement of the protocol for in vitro somatic embryogenesis in Cyclamen persicum are deduced. A set of physiological markers is proposed for efficient molecular control of the process of somatic embryogenesis in C. persicum. The general suitability of expression profiling for the development and improvement of micropropagation methods is discussed.

The effect of optotype presentation duration on acuity estimates revisited.

BACKGROUND: A high reproducibility of visual acuity estimates is important when monitoring disease progression or treatment success. One factor that may affect the result of an acuity measurement is the duration of optotype presentation. For times below 1 s, previous studies have convincingly shown that acuity estimates increase with presentation duration. For durations above 1 s, the situation is less clear. METHODS: We have reassessed this issue using the Freiburg Visual Acuity Test with normal subjects. Presentation durations of 0.1 s, 1 s, and 10 s were assessed. RESULTS: Confirming previous findings, in all subjects acuity estimates in the 1-s condition were higher than those in the 0.1-s condition, on average nearly by a factor of 2, equivalent to 3 lines. However, in 12 out of 14 subjects, acuity estimates increased further with a presentation duration of 10 s, on average by 23% (P=0.002), or roughly 1 line. Test-retest variability improved by 49% (P=0.003). These findings can be explained by a simple statistical model of acuity fluctuations. Cognitive processing may also be a relevant factor. Interestingly, most observers subjectively felt that they could perceive the optotypes best in the 1-s condition. CONCLUSION: The results highlight the importance of standardizing presentation durations when high reproducibility is required.

'Who's who' in two different flower types of Calluna vulgaris (Ericaceae): morphological and molecular analyses of flower organ identity.

BACKGROUND: The ornamental crop Calluna vulgaris is of increasing importance to the horticultural industry in the northern hemisphere due to a flower organ mutation: the flowers of the 'bud-flowering' phenotype remain closed i.e. as buds throughout the total flowering period and thereby maintain more colorful flowers for a longer period of time than the wild-type. This feature is accompanied and presumably caused by the complete lack of stamens. Descriptions of this botanical particularity are inconsistent and partially conflicting. In order to clarify basic questions of flower organ identity in general and stamen loss in detail, a study of the wild-type and the 'bud-flowering' flower type of C. vulgaris was initiated. RESULTS: Flowers were examined by macro- and microscopic techniques. Organ development was investigated comparatively in both the wild-type and the 'bud-flowering' type by histological analyses. Analysis of epidermal cell surface structure of vegetative tissues and perianth organs using scanning electron microscopy revealed that in wild-type flowers the outer whorls of colored organs may be identified as sepals, while the inner ones may be identified as petals. In the 'bud-flowering' type, two whorls of sepals are directly followed by the gynoecium. Both, petals and stamens, are completely missing in this flower type. The uppermost whorl of green leaves represents bracts in both flower types. In addition, two MADS-box genes (homologs of AP3/DEF and SEP1/2) were identified in C. vulgaris using RACE-PCR. Expression analysis by qRT-PCR was conducted for both genes in leaves, bracts, sepals and petals. These experiments revealed an expression pattern supporting the organ classification based on morphological characteristics. CONCLUSIONS: Organ identity in both wild-type and 'bud-flowering' C. vulgaris was clarified using a combination of microscopic and molecular methods. Our results for bract, sepal and petal organ identity are supported by the 'ABCDE model'. However, loss of stamens in the 'bud-flowering' phenotype is an exceptional flower organ modification that cannot be explained by modified spatial expression of known organ identity genes.

Apoptosis and loss of adhesion of bronchial epithelial cells in asthma.

BACKGROUND: Asthma is an inflammatory airway disease associated with infiltration of T cells and eosinophils, increased levels of pro-inflammatory cytokines, and shedding of bronchial epithelial cells (EC). We have recently shown that T cells and eosinophils cooperate in inducing bronchial EC apoptosis in asthma through secretion of IFN-gamma and TNF-alpha. Since EC shedding is a histologic hallmark of asthma, the intercellular junction of EC may be a target of pro-inflammatory cytokines. METHODS: Bronchial EC, cultured and exposed to IFN-gamma and TNF-alpha, were studied for the expression of adhesion molecules and apoptosis. In addition, the epithelial layer of bronchial biopsies from asthma patients was evaluated for apoptosis, shedding, and expression of adhesion molecules. RESULTS: We demonstrate that the induction of EC apoptosis is accompanied by loss of E-cadherin. In situ examination of E-cadherin in asthma revealed a reduction in its expression on EC membranes. In contrast, the in vitro and in vivo expression of beta1-integrins and intercellular adhesion molecule-1 (ICAM-1) increased on EC during asthmatic airway inflammation. CONCLUSIONS: Loss of cadherin-mediated intercellular adhesion and apoptosis could account for fragility and shedding of EC in asthma, especially since this occurs between columnar and basal EC.

T cells and eosinophils cooperate in the induction of bronchial epithelial cell apoptosis in asthma.

BACKGROUND: Asthma is an inflammatory airway disease associated with an infiltration of T cells and eosinophils, increased levels of pro-inflammatory cytokines, and shedding of bronchial epithelial cells (ECs). OBJECTIVE: Shedding of bronchial ECs is characterized by loss of the normal bronchial pseudostratified epithelium and the maintenance of a few basal cells on a thickened basement membrane. The aim of this study was to investigate whether, and by which mechanism, T cells and eosinophils can cause damage to airway ECs. METHODS: Bronchial ECs, cultured and exposed to cytokines, eosinophil cationic protein, activated T cells, and eosinophils were studied for the expression of apoptosis receptors (flow cytometry, immunoblotting, and RNA expression) and for the susceptibility for undergoing apoptosis. In addition, bronchial biopsy specimens from patients with asthma were evaluated for EC apoptosis. RESULTS: We demonstrate herein that the respiratory epithelium is an essential target of the inflammatory attack by T cells and eosinophils. Bronchial ECs underwent cytokine-induced cell death with DNA fragmentation and morphologic characteristics of apoptosis mediated by activated T cells and eosinophils. T cell- and eosinophil-induced EC apoptosis was blocked by inhibition of IFN-alpha and TNF-alpha; the Fas ligand-Fas pathway appears to be less important. Recombinant eosinophil cationic protein induced mainly necrosis of ECs. Furthermore, we demonstrated in situ apoptotic features of ECs in bronchial biopsy specimens of asthmatic patients. CONCLUSION: T cell- and eosinophil-induced apoptosis represents a key pathogenic event leading to EC shedding in asthma.