Voluntary Modulation of Hemodynamic Responses in Swallowing Related Motor Areas: A Near-Infrared Spectroscopy-Based Neurofeedback Study

In the present study, we show for the first time that motor imagery of swallowing, which is defined as the mental imagination of a specific motor act without overt movements by muscular activity, can be successfully used as mental strategy in a neurofeedback training paradigm. Furthermore, we demonstrate its effects on cortical correlates of swallowing function. Therefore, N = 20 healthy young adults were trained to voluntarily increase their hemodynamic response in swallowing related brain areas as assessed with near-infrared spectroscopy (NIRS). During seven training sessions, participants received either feedback of concentration changes in oxygenated hemoglobin (oxy-Hb group, N = 10) or deoxygenated hemoglobin (deoxy-Hb group, N = 10) over the inferior frontal gyrus (IFG) during motor imagery of swallowing. Before and after the training, we assessed cortical activation patterns during motor execution and imagery of swallowing. The deoxy-Hb group was able to voluntarily increase deoxy-Hb over the IFG during imagery of swallowing. Furthermore, swallowing related cortical activation patterns were more pronounced during motor execution and imagery after the training compared to the pre-test, indicating cortical reorganization due to neurofeedback training. The oxy-Hb group could neither control oxy-Hb during neurofeedback training nor showed any cortical changes. Hence, successful modulation of deoxy-Hb over swallowing related brain areas led to cortical reorganization and might be useful for future treatments of swallowing dysfunction.     

SUPFAM: A database of sequence superfamilies of protein domains

Background  

SUPFAM database is a compilation of superfamily relationships between protein domain families of either known or unknown 3-D structure. In SUPFAM, sequence families from Pfam and structural families from SCOP are associated, using profile matching, to result in sequence superfamilies of known structure. Subsequently all-against-all family profile matches are made to deduce a list of new potential superfamilies of yet unknown structure.     

Trait means or variance—What determines plant species' local and regional occurrence in fragmented dry grasslands?

One of the few laws in ecology is that communities consist of few common and many rare taxa. Functional traits may help to identify the underlying mechanisms of this community pattern, since they correlate with different niche dimensions. However, comprehensive studies are missing that investigate the effects of species mean traits (niche position) and intraspecific trait variability (ITV, niche width) on species abundance. In this study, we investigated fragmented dry grasslands to reveal trait‐occurrence relationships in plants at local and regional scales. We predicted that (a) at the local scale, species occurrence is highest for species with intermediate traits, (b) at the regional scale, habitat specialists have a lower species occurrence than generalists, and thus, traits associated with stress‐tolerance have a negative effect on species occurrence, and (c) ITV increases species occurrence irrespective of the scale. We measured three plant functional traits (SLA = specific leaf area, LDMC = leaf dry matter content, plant height) at 21 local dry grassland communities (10 m × 10 m) and analyzed the effect of these traits and their variation on species occurrence. At the local scale, mean LDMC had a positive effect on species occurrence, indicating that stress‐tolerant species are the most abundant rather than species with intermediate traits (hypothesis 1). We found limited support for lower specialist occurrence at the regional scale (hypothesis 2). Further, ITV of LDMC and plant height had a positive effect on local occurrence supporting hypothesis 3. In contrast, at the regional scale, plants with a higher ITV of plant height were less frequent. We found no evidence that the consideration of phylogenetic relationships in our analyses influenced our findings. In conclusion, both species mean traits (in particular LDMC) and ITV were differently related to species occurrence with respect to spatial scale. Therefore, our study underlines the strong scale‐dependency of trait‐abundance relationships.     

The catalytic activity of protein-disulfide isomerase requires a conformationally flexible molecule

Protein-disulfide isomerase (PDI) catalyzes the formation of the correct pattern of disulfide bonds in secretory proteins. A low resolution crystal structure of yeast PDI described here reveals large scale conformational changes compared with the initially reported structure, indicating that PDI is a highly flexible molecule with its catalytic domains, a and a', representing two mobile arms connected to a more rigid core composed of the b and b' domains. Limited proteolysis revealed that the linker between the a domain and the core is more susceptible to degradation than that connecting the a' domain to the core. By restricting the two arms with inter-domain disulfide bonds, the molecular flexibility of PDI, especially that of its a domain, was demonstrated to be essential for the enzymatic activity in vitro and in vivo. The crystal structure also featured a PDI dimer, and a propensity to dimerize in solution and in the ER was confirmed by cross-linking experiments and the split green fluorescent protein system. Although sedimentation studies suggested that the self-association of PDI is weak, we hypothesize that PDI exists as an interconvertible mixture of monomers and dimers in the endoplasmic reticulum due to its high abundance in this compartment.     

The ultrastructure of the rat esophageal epithelium during ontogenesis]

The development of the epithelium of the rat esophagus was examined continuously from the 13th day post-conception until one day post-partum. Besides the single-results at different phases of development the knowledge, that the esophageal ontogeny of different mammalians may be considerably different, is of special importance. To this matter of fact was not paid attention in present literature, but the authors accentuate common things. The significant results during development are the following: 1. The completely undifferentiated epithelium of the 13th day at the same time develops basement-membrane and basic membrane of the cytoplasm. The organelles are under construction. Centriols in cells near to the lumen are seen in connection to the single-cilia, which occur till the 17th day of ontogeny. These essentially differ from cilia of the ciliated epithelium. 2. The cylindrical epithelium constitutes until the 16th day. Afterwards the first synthetic productivity like organisation of filaments are observed. By that superficial cells loose their capacity to divide. 3. On the 17th day intercellular spaces between neighbouring cells at the lumen abruptly rip up. In loco cylindrical cells change to squamous cells. There are no essential differences in time between cranial and caudal parts of the esophagus which proofs an entodermal genesis of the epithelium. 4. Changes in the ultrastructure at about 19 days p.c. cause the epithelium's keratinization. 5. 21 days p.c. few cilia-bearing cells scattered between the cells in keratinization are to be seen. 6. Before birth superficial cells become separated and are shed from the surface completely post-partum.     

How long should angiotensin-converting enzyme inhibitors be given to patients following myocardial infarction: implications of the HOPE trial

Long-term treatment with angiotensin-converting enzyme inhibitors reduces post-infarction morbidity and mortality in patients with left ventricular (LV) systolic dysfunction or symptomatic heart failure. Until recently, the effect of such treatment in patients with preserved LV function has not been known. The results from the Heart Outcome Prevention Evaluation trial have indicated that long-term treatment with ramipril leads to a significant reduction in cardiovascular events in patients with atherosclerotic disease, including those with prior myocardial infarction and preserved LV function. These results suggest that long-term angiotensin-converting enzyme inhibition should also be considered in post-infarction patients with normal cardiac function.     

Structural basis of siRNA recognition by TRBP double‐stranded RNA binding domains

The accurate cleavage of pre‐micro(mi)RNAs by Dicer and mi/siRNA guide strand selection are important steps in forming the RNA‐induced silencing complex (RISC). The role of Dicer binding partner TRBP in these processes remains poorly understood. Here, we solved the solution structure of the two N‐terminal dsRNA binding domains (dsRBDs) of TRBP in complex with a functionally asymmetric siRNA using NMR, EPR, and single‐molecule spectroscopy. We find that siRNA recognition by the dsRBDs is not sequence‐specific but rather depends on the RNA shape. The two dsRBDs can swap their binding sites, giving rise to two equally populated, pseudo‐symmetrical complexes, showing that TRBP is not a primary sensor of siRNA asymmetry. Using our structure to model a Dicer‐TRBP‐siRNA ternary complex, we show that TRBP's dsRBDs and Dicer's RNase III domains bind a canonical 19 base pair siRNA on opposite sides, supporting a mechanism whereby TRBP influences Dicer‐mediated cleavage accuracy by binding the dsRNA region of the pre‐miRNA during Dicer cleavage.