Sensory interaction with central ‘generators’ during respiration in the dogfish

Summary The activity in sensory and motor nerves of the gills was recorded from selected branches of the vagus nerve in decerebrate dogfish,Scyliorhinus canicula. Vagal motoneuronal activity was observed at the start of the rapid pharyngeal contraction and was followed by sensory nerve activity which preceded the slow expansion phase. Rhythmical vagal motoneuronal activity was still present after all movements had been prevented by curare paralysis although the frequency of the rhythm was higher than in the ventilating fish. Electrical stimulation of vagal sensory fibres had 3 effects on the ventilatory movements. (1) It evoked a reflex contraction of several gill muscles after a latency of about 11 ms. (2) It could reset the respiratory cycle because a stimulus given during expansion delayed the onset of the subsequent contraction. (3) The stimulus could entrain the rhythm if it was given continuously at a frequency close to that of ventilation. The vagal motor rhythm was disrupted by trigeminal nerve stimulation in the paralyzed fish but not if the motor rhythm was being entrained by vagal nerve stimulation. Vagal sensory activity may be important, therefore, in maintaining the stability of the generating circuits.Abbreviation LED Light emitting diode     

<Emphasis Type="Italic">mab-31</Emphasis> and the TGF-β pathway act in the ray lineage to pattern <Emphasis Type="Italic">C. elegans</Emphasis>male sensory rays

Background  

C. elegans TGF-β-like Sma/Mab signaling pathway regulates both body size and sensory ray patterning. Most of the components in this pathway were initially identified by genetic screens based on the small body phenotype, and many of these mutants display sensory ray patterning defect. At the cellular level, little is known about how and where these components work although ray structural cell has been implicated as one of the targets. Based on the specific ray patterning abnormality, we aim to identify by RNAi approach additional components that function specifically in the ray lineage to elucidate the regulatory role of TGF-β signaling in ray differentiation.     

Brood Size Affects Behavior, Interclutch Interval, LH Levels, and Weight in Ring Dove (Streptopelia risoria) Breeding Pairs

This study examines the effects of experimental manipulation of brood size (one or two squabs) on the behavior, interclutch interval, plasma LH concentrations, and weights of ring dove parents. Twelve dove pairs were observed, sampled, and weighed over a cycle with one and a cycle with two squabs. Before hatch, no parameter showed any difference between pairs which would subsequently have one or have two squabs. After hatch, males and females having one squab fed less, while males showed more perch-, bow-, and nest-cooing over the 2 weeks after hatch. Females also showed more nest-cooing with one squab and a shorter interclutch interval. For both sexes the plasma LH concentrations were higher when rearing a single squab, showed a lesser decrease after hatch, and increased more rapidly. Both sexes also showed a smaller weight loss when rearing a single squab. The results show that the intricate relationships between behavior, physiology, and reproduction in the ring dove are tuned to brood size and emphasize the latter factor as an important and meaningful variable in the doves' reproductive cycle.     

High throughput screening to investigate the interaction of stem cells with their extracellular microenvironment

Stem cells in vivo are housed within a functional microenvironment termed the “stem cell niche.” As the niche components can modulate stem cell behaviors like proliferation, migration and differentiation, evaluating these components would be important to determine the most optimal platform for their maintenance or differentiation. In this review, we have discussed methods and technologies that have aided in the development of high throughput screening assays for stem cell research, including enabling technologies such as the well-established multiwell/microwell plates and robotic spotting, and emerging technologies like microfluidics, micro-contact printing and lithography. We also discuss the studies that utilized high throughput screening platform to investigate stem cell response to extracellular matrix, topography, biomaterials and stiffness gradients in the stem cell niche. The combination of the aforementioned techniques could lay the foundation for new perspectives in further development of high throughput technology and stem cell research.