Growth,cell division and branching patterns of Schizophyllum commune Fr. single basidiospore germlings

Summary Basidiospores of Schizophyllum commune Fr. were germinated and observed growing on microscope slides containing minimal medium. Micron measurements of the young germlings were made along with observations of nuclear division, cross wall formation and branching. Growth patterns and relationships of various parts of the developing germling were compared. Linear relations were observed between the length of the main axis and the number of cells in the main axis, and the number of primary branches in relation to the number of cells in the main axis while other comparisons were less conclusive. In addition to cell division occurring in terminal cells of hyphae, mature subterminal cells also delimited further with a somewhat regular cleavage division. Lack of synchrony in nuclear division between any of the cells of the germling hypha implicated autonomy of the individual components once delimitation had occurred.     

Die Beurteilung der Entfernung beim Sprung von Galago senegalensis

Zusammenfassung Die Entfernungsschätzung bei Galagos kann durch die Helligkeit und Strukturierung eines Zieles, das die Tiere anspringen, beeinflußt werden. Bei Sprungweiten von 140–160 cm betrug der Unterschied in der Beurteilung der Entfernung eines Zieles je nach seiner Helligkeit bis zu 6 cm. Als Meßkriterium diente der von den Tieren beim Absprang aufgewandte Impuls, der weglos gemessen werden kann.

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Distance Estimation in the leap of Galago senegalensis

Summary The estimation of distance in bushbabies (Galago senegalensis) may be influenced by the brightness and the structure of the landing target towards which the animals leap. When leaping distances of 140–160 cm were tested, the estimation of distance was inaccurate up to 6 cm, depending on the target's brightness. As a measurement for the judgement, the magnitude of the leap-off impulse was used.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Distinguishing epidemic waves from disease spillover in a wildlife population

Serengeti lions frequently experience viral outbreaks. In 1994, one-third of Serengeti lions died from canine distemper virus (CDV). Based on the limited epidemiological data available from this period, it has been unclear whether the 1994 outbreak was propagated by lion-to-lion transmission alone or involved multiple introductions from other sympatric carnivore species. More broadly, we do not know whether contacts between lions allow any pathogen with a relatively short infectious period to percolate through the population (i.e. reach epidemic proportions). We built one of the most realistic contact network models for a wildlife population to date, based on detailed behavioural and movement data from a long-term lion study population. The model allowed us to identify previously unrecognized biases in the sparse data from the 1994 outbreak and develop methods for judiciously inferring disease dynamics from typical wildlife samples. Our analysis of the model in light of the 1994 outbreak data strongly suggest that, although lions are sufficiently well connected to sustain epidemics of CDV-like diseases, the 1994 epidemic was fuelled by multiple spillovers from other carnivore species, such as jackals and hyenas.     

A genetic module regulates the melanization response of Anopheles to Plasmodium

Two modes of refractoriness to Plasmodium, ookinete lysis and melanization, are known in the malaria vector, Anopheles gambiae. Melanization, a potent insect immune response, is manifested in a genetically selected refractory strain and in susceptible mosquitoes that are depleted of specific C-type lectins (CTLs). Here we use a systematic in vivo RNA interference-mediated reverse genetic screen and other recent results to define a melanization-regulating genetic module or network. It encompasses at least 14 genes, including those that encode five Easter-like clip domain serine proteases and four Masquerade-like serine protease homologues of the mosquito CLIPB and CLIPA subfamilies respectively. We show that several but not all CLIPB genes promote Plasmodium melanization, exhibiting partial functional overlap and synergy. We also report that several CLIPA genes have contrasting roles: CLIPA8 is essential for parasite melanization, while three other CLIPAs are novel synergistic inhibitors of this response. Importantly, the roles of certain CLIPAs and CLIPBs are strain specific, indicating that this network may differ between strains. Finally, we provide evidence that in susceptible mosquitoes melanization induced by knockdown of either CTL4 or CLIPA2/CLIPA5 directly kills ookinetes, in contrast to refractory mosquitoes where it merely disposes of dead parasites.     

Adipose stem cell-derived extracellular matrix represents a promising biomaterial by inducing spontaneous formation of prevascular-like structures by mvECs

Tissue constructs of physiologically relevant scale require a vascular system to maintain cell viability. However, in vitro vascularization of engineered tissues is still a major challenge. Successful approaches are based on a feeder layer (FL) to support vascularization. Here, we investigated whether the supporting effect on the self-assembled formation of prevascular-like structures by microvascular endothelial cells (mvECs) originates from the FL itself or from its extracellular matrix (ECM). Therefore, we compared the influence of ECM, either derived from adipose-derived stem cells (ASCs) or adipogenically differentiated ASCs, with the classical cell-based FL. All cell-derived ECM (cdECM) substrates enabled mvEC growth with high viability. Prevascular-like structures were visualized by immunofluorescence staining of endothelial surface protein CD31 and could be observed on all cdECM and FL substrates but not on control substrate collagen I. On adipogenically differentiated ECM, longer and higher branched structures could be found compared with stem cell cdECM. An increased concentration of proangiogenic factors was found in cdECM substrates and FL approaches compared with controls. Finally, the expression of proteins associated with tube formation (E-selectin and thrombomodulin) was confirmed. These results highlight cdECM as promising biomaterial for adipose tissue engineering by inducing the spontaneous formation of prevascular-like structures by mvECs.     

Dissociation of motor task-induced cortical excitability and pain perception changes in healthy volunteers

Background

There is evidence that interventions aiming at modulation of the motor cortex activity lead to pain reduction. In order to understand further the role of the motor cortex on pain modulation, we aimed to compare the behavioral (pressure pain threshold) and neurophysiological effects (transcranial magnetic stimulation (TMS) induced cortical excitability) across three different motor tasks.

Methodology/Principal Findings

Fifteen healthy male subjects were enrolled in this randomized, controlled, blinded, cross-over designed study. Three different tasks were tested including motor learning with and without visual feedback, and simple hand movements. Cortical excitability was assessed using single and paired-pulse TMS measures such as resting motor threshold (RMT), motor-evoked potential (MEP), intracortical facilitation (ICF), short intracortical inhibition (SICI), and cortical silent period (CSP). All tasks showed significant reduction in pain perception represented by an increase in pressure pain threshold compared to the control condition (untrained hand). ANOVA indicated a difference among the three tasks regarding motor cortex excitability change. There was a significant increase in motor cortex excitability (as indexed by MEP increase and CSP shortening) for the simple hand movements.

Conclusions/Significance

Although different motor tasks involving motor learning with and without visual feedback and simple hand movements appear to change pain perception similarly, it is likely that the neural mechanisms might not be the same as evidenced by differential effects in motor cortex excitability induced by these tasks. In addition, TMS-indexed motor excitability measures are not likely good markers to index the effects of motor-based tasks on pain perception in healthy subjects as other neural networks besides primary motor cortex might be involved with pain modulation during motor training.     

A test case for structure-based functional assignment: the 1.2 A crystal structure of the yjgF gene product from Escherichia coli

The YER057c/YIL051c/YjgF protein family is a set of 24 full-length homologs, each approximately 130 residues in length, and each with no known function or relationship to proteins of known structure. To determine the function of this family, the structure of one member--the YjgF protein from Escherichia coli--was solved and refined at a resolution of 1.2 A. The YjgF molecule is a homotrimer with exact threefold symmetry. Its tertiary and quaternary structures are related to that of Bacillus subtilis chorismate mutase, although their active sites are completely different. The YjgF protein has an active site curiously similar to protein tyrosine phosphatases, including a covalently modified cysteine, but it is unlikely to be functionally related. The lessons learned from this attempt to deduce function from structure may be useful to future projects in structural genomics.