340 research outputs found
Photosynthesis in C3-C4 intermediate Moricandia species.
Evolution of C4 photosynthesis is not distributed evenly in the plant kingdom. Particularly interesting is the situation in the Brassicaceae, because the family contains no C4 species, but several C3-C4 intermediates, mainly in the genus Moricandia Investigation of leaf anatomy, gas exchange parameters, the metabolome, and the transcriptome of two C3-C4 intermediate Moricandia species, M. arvensis and M. suffruticosa, and their close C3 relative M. moricandioides enabled us to unravel the specific C3-C4 characteristics in these Moricandia lines. Reduced CO2 compensation points in these lines were accompanied by anatomical adjustments, such as centripetal concentration of organelles in the bundle sheath, and metabolic adjustments, such as the balancing of C and N metabolism between mesophyll and bundle sheath cells by multiple pathways. Evolution from C3 to C3-C4 intermediacy was probably facilitated first by loss of one copy of the glycine decarboxylase P-protein, followed by dominant activity of a bundle sheath-specific element in its promoter. In contrast to recent models, installation of the C3-C4 pathway was not accompanied by enhanced activity of the C4 cycle. Our results indicate that metabolic limitations connected to N metabolism or anatomical limitations connected to vein density could have constrained evolution of C4 in Moricandia
The Neurotrophic Receptor Ntrk2 Directs Lymphoid Tissue Neovascularization during Leishmania donovani Infection
The neurotrophic tyrosine kinase receptor type 2 (Ntrk2, also known as TrkB) and its ligands brain derived neurotrophic factor (Bdnf), neurotrophin-4 (NT-4/5), and neurotrophin-3 (NT-3) are known primarily for their multiple effects on neuronal differentiation and survival. Here, we provide evidence that Ntrk2 plays a role in the pathologic remodeling of the spleen that accompanies chronic infection. We show that in Leishmania donovani-infected mice, Ntrk2 is aberrantly expressed on splenic endothelial cells and that new maturing blood vessels within the white pulp are intimately associated with F4/80hiCD11bloCD11c+ macrophages that express Bdnf and NT-4/5 and have pro-angiogenic potential in vitro. Furthermore, administration of the small molecule Ntrk2 antagonist ANA-12 to infected mice significantly inhibited white pulp neovascularization but had no effect on red pulp vascular remodeling. We believe this to be the first evidence of the Ntrk2/neurotrophin pathway driving pathogen-induced vascular remodeling in lymphoid tissue. These studies highlight the therapeutic potential of modulating this pathway to inhibit pathological angiogenesis
Microsecond Time-Resolved Absorption Spectroscopy Used to Study CO Compounds of Cytochrome bd from Escherichia coli
Cytochrome bd is a tri-heme (b558, b595, d) respiratory oxygen reductase that is found in many bacteria including pathogenic
species. It couples the electron transfer from quinol to O2 with generation of an electrochemical proton gradient. We
examined photolysis and subsequent recombination of CO with isolated cytochrome bd from Escherichia coli in oneelectron
reduced (MV) and fully reduced (R) states by microsecond time-resolved absorption spectroscopy at 532-nm
excitation. Both Soret and visible band regions were examined. CO photodissociation from MV enzyme possibly causes fast
(t,1.5 ms) electron transfer from heme d to heme b595 in a small fraction of the protein, not reported earlier. Then the
electron migrates to heme b558 (t,16 ms). It returns from the b-hemes to heme d with t,180 ms. Unlike cytochrome bd in
the R state, in MV enzyme the apparent contribution of absorbance changes associated with CO dissociation from heme d is
small, if any. Photodissociation of CO from heme d in MV enzyme is suggested to be accompanied by the binding of an
internal ligand (L) at the opposite side of the heme. CO recombines with heme d (t,16 ms) yielding a transient
hexacoordinate state (CO-Fe2+
-L). Then the ligand slowly (t,30 ms) dissociates from heme d. Recombination of CO with a
reduced heme b in a fraction of the MV sample may also contribute to the 30-ms phase. In R enzyme, CO recombines to
heme d (t,20 ms), some heme b558 (t,0.2–3 ms), and finally migrates from heme d to heme b595 (t,24 ms) in ,5% of the
enzyme population. Data are consistent with the recent nanosecond study of Rappaport et al. conducted on the
membranes at 640-nm excitation but limited to the Soret band. The additional phases were revealed due to differences in
excitation and other experimental conditions
Coincidence of paroxysmal supraventricular tachycardia and panic disorder: two case reports
Panic disorder (PD) is characterised by sudden attacks of intense fear with somatic symptoms including palpitations and tachycardia. Reciprocally, palpitations caused by paroxysmal supraventricular tachycardia (PSVT) are commonly associated with anxiety and may therefore be misdiagnosed as PD. As demonstrated by two case reports, PSVT and PD can occur comorbidly in a chronological sequence, with PSVT possibly precipitating and maintaining PD via interoceptive processes or, alternatively, with PD increasing the risk for PSVT by elevating stress levels. As both PSVT and PD require different treatments, potentially helpful differential clinical diagnostic criteria are proposed
Training in the practice of noninvasive brain stimulation: Recommendations from an IFCN committee
As the field of noninvasive brain stimulation (NIBS) expands, there is a growing need for comprehensive guidelines on training practitioners in the safe and effective administration of NIBS techniques in their various research and clinical applications. This article provides recommendations on the structure and content of this training. Three different types of practitioners are considered (Technicians, Clinicians, and Scientists), to attempt to cover the range of education and responsibilities of practitioners in NIBS from the laboratory to the clinic. Basic or core competencies and more advanced knowledge and skills are discussed, and recommendations offered regarding didactic and practical curricular components. We encourage individual licensing and governing bodies to implement these guidelines
Online prediction of others’ actions: the contribution of the target object, action context and movement kinematics
Previous research investigated the contributions of target objects, situational context and movement kinematics to action prediction separately. The current study addresses how these three factors combine in the prediction of observed actions. Participants observed an actor whose movements were constrained by the situational context or not, and object-directed or not. After several steps, participants had to indicate how the action would continue. Experiment 1 shows that predictions were most accurate when the action was constrained and object-directed. Experiments 2A and 2B investigated whether these predictions relied more on the presence of a target object or cues in the actor’s movement kinematics. The target object was artificially moved to another location or occluded. Results suggest a crucial role for kinematics. In sum, observers predict actions based on target objects and situational constraints, and they exploit subtle movement cues of the observed actor rather than the direct visual information about target objects and context
Description of two new species of Myxobolus Bütschli, 1892, M. peleci n. sp. and M. cultrati n. sp., detected during an intensive mortality of the sichel, Pelecus cultratus (L.) (Cyprinidae), in Lake Balaton, Hungary
Factorial validity and measurement invariance across gender groups of the German version of the Interpersonal Reactivity Index
The Interpersonal Reactivity Index (IRI) is the most widely used measure of empathy, but its factorial validity has been questioned. The present research investigates the factorial validity of the German adaptation of the IRI, the "Saarbrücker Persönlichkeitsfragebogen SPF-IRI". Confirmatory Factor Analyses (CFA) and Exploratory Structural Equation Modeling (ESEM) were used to test the theoretically predicted four-factor model. Across two subsamples ESEM outperformed CFA. Substantial cross-loadings were evident in ESEM. Measurement invariance (MI) across gender groups was tested using ESEM in the combined sample. Strict MI (invariant factor loadings, intercepts, residuals) could be established, and variances and covariances were also equal. Differences for latent means were evident. Women scored higher on fantasy, empathic concern, and personal distress. No significant differences were found for perspective taking. Mean differences were due to real differences on latent variables and not a result of measurement bias. Results support the factorial validity of the German SPF-IRI. The heterogeneity of empathy and the unclear differentiation between cognitive and emotional aspects might be a source for the unclear differentiation of scales
Well-aligned Nickel Nanochains Synthesized by a Template-free Route
Highly uniform and well-aligned one-dimensional Ni nanochains with controllable diameters, including 33, 78, and 120 nm, have been synthesized by applying an external magnetic field without any surface modifying agent. The formation can be explained by the interactions of magnetic dipoles in the presence of applied magnetic field. Magnetic measurements demonstrate that the shape anisotropy dominates the magnetic anisotropy. The demagnetization factor, ∆N, is in the range of 0.23–0.36
Vertical Heterophoria and Postural Control in Nonspecific Chronic Low Back Pain
The purpose of this study was to test postural control during quiet standing in
nonspecific chronic low back pain (LBP) subjects with vertical heterophoria (VH)
before and after cancellation of VH; also to compare with healthy subjects with,
and without VH. Fourteen subjects with LBP took part in this study. The postural
performance was measured through the center of pressure displacements with a
force platform while the subjects fixated on a target placed at either 40 or 200
cm, before and after VH cancellation with an appropriate prism. Their postural
performance was compared to that of 14 healthy subjects with VH and 12 without
VH (i.e. vertical orthophoria) studied previously in similar conditions. For LBP
subjects, cancellation of VH with a prism improved postural performance. With
respect to control subjects (with or without VH), the variance of speed of the
center of pressure was higher, suggesting more energy was needed to stabilize
their posture in quiet upright stance. Similarly to controls, LBP subjects
showed higher postural sway when they were looking at a target at a far distance
than at a close distance. The most important finding is that LBP subjects with
VH can improve their performance after prism-cancellation of their VH. We
suggest that VH reflects mild conflict between sensory and motor inputs involved
in postural control i.e. a non optimal integration of the various signals. This
could affect the performance of postural control and perhaps lead to pain.
Nonspecific chronic back pain may results from such prolonged conflict
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