Shifting Patterns of Nitrogen Excretion and Amino Acid Catabolism Capacity during the Life Cycle of the Sea Lamprey (\u3cem\u3ePetromyzon mariunus\u3c/em\u3e)

The jawless fish, the sea lamprey (Petromyzon marinus), spends part of its life as a burrow-dwelling, suspension-feeding larva (ammocoete) before undergoing a metamorphosis into a free swimming, parasitic juvenile that feeds on the blood of fishes. We predicted that animals in this juvenile, parasitic stage have a great capacity for catabolizing amino acids when large quantities of protein-rich blood are ingested. The sixfold to 20-fold greater ammonia excretion rates (JAmm) in postmetamorphic (nonfeeding) and parasitic lampreys compared with ammocoetes suggested that basal rates of amino acid catabolism increased following metamorphosis. This was likely due to a greater basal amino acid catabolizing capacity in which there was a sixfold higher hepatic glutamate dehydrogenase (GDH) activity in parasitic lampreys compared with ammocoetes. Immunoblotting also revealed that GDH quantity was 10-fold and threefold greater in parasitic lampreys than in ammocoetes and upstream migrant lampreys, respectively. Higher hepatic alanine and aspartate aminotransferase activities in the parasitic lampreys also suggested an enhanced amino acid catabolizing capacity in this life stage. In contrast to parasitic lampreys, the twofold larger free amino acid pool in the muscle of upstream migrant lampreys confirmed that this period of natural starvation is accompanied by a prominent proteolysis. Carbamoyl phosphate synthetase III was detected at low levels in the liver of parasitic and upstream migrant lampreys, but there was no evidence of extrahepatic (muscle, intestine) urea production via the ornithine urea cycle. However, detection of arginase activity and high concentrations of arginine in the liver at all life stages examined infers that arginine hydrolysis is an important source of urea. We conclude that metamorphosis is accompanied by a metabolic reorganization that increases the capacity of parasitic sea lampreys to catabolize intermittently large amino acid loads arising from the ingestion of protein rich blood from their prey/hosts. The subsequent generation of energy-rich carbon skeletons can then be oxidized or retained for glycogen and fatty acid synthesis, which are essential fuels for the upstream migratory and spawning phases of the sea lamprey’s life cycle

Hyperbolic boundaries vs. hyperbolic groups

The aim of these notes is to connect the theory of hyperbolic and relatively hyperbolic groups to the theory of manifolds and Kleinian groups. We survey some of the extensive work that has been done in the field, and explain many examples. These notes are based on lectures given by the third author at CIRM in the Summer of 2018.Comment: These notes are based on lectures given by the third author at CIRM in the Summer of 201

Development of an alternative harvesting method using pH to detach adherent cells from microcarriers

Peripheral nerve injuries are common in Canada, affecting 2.8% of trauma patients treated every year. Current repair strategies are inadequate and repair is often suboptimal with only 25% of patients recovering full motor function and only 3% regaining full sensory function. Because of this, the field is turning toward regenerative medicine to develop a cellular therapy using Schwann cells to repair injured nerves. Schwann cells differentiated from skin derived precursors (SKP-SCs) are a promising cell type as they are easily obtained and allow for autologous therapy. To be able to generate clinically relevant numbers of SKP-SCs, bioreactors need to be used. Since SKP-SCs are an adherent cell type, to be expanded in suspension bioreactors, small spherical beads known as microcarriers need to be used. Our lab has previously shown that these SKP-SCs readily attach to the microcarriers and grow in stirred suspension bioreactors. We have also shown that by controlling the culture parameters, we can increase the maximum cell density compared to conventional static culture methods. One of the biggest hurdles that remains is an efficient harvesting method that can be scaled up to clinical applications. Current cell detachment protocols use enzymatic based solutions to remove the cells from the surface of the microcarriers. These methods work well in removing the cells, however, they are very labour intensive as they require many washing steps and taking the reactors offline. Therefore, we looked into an alternative method for the detachment of SKP-SCs from microcarriers that will allow for an inline detachment process. This new method is based on previous research done in our lab using high pH solutions to dissociate aggregates. First we investigated the detachment efficiency in static. Cells were cultured in 6-well plates until confluency and then harvested with solutions ranging from pH 8-9.5. With a pH of 9 and an incubation time of 30 minutes, we were able to recover 75% of cells when compared to traditional enzymatic harvesting. Following this we performed a qualitative analysis on the detachment of the SKP-SCs from the microcarriers to determine if this method has potential. Small 3mL samples were taken and solutions with pHs 8.5, 9, and 9.5 were added and incubated for 30 minutes and agitated every 5 minutes. We found that the cells detached with a high efficiency after 30 minutes with a pH of only 8.5. This was then quantified while maintaining a viability of above 90%. Following this we tested this method in harvesting full 125mL bioreactors. We evaluated different pH, agitation rates, and incubation times. We also assessed the ability of the cells to reattach to microcarriers and continue to expand over several serial passages to ensure there were no negative effects on the cells. Lastly we looked at using this method in our controlled bioreactors to increase the pH without the addition of anything else. Based on our results, increasing the pH of the culture medium can detach the SKP-SCs from microcarriers at a pH as low as 8.5 which allows for minimal cell damage while still detaching cells. We also noted that when the pH gets too high (\u3e9.5), the microcarriers begin to clump together causing large aggregates of microcarriers which could lead to clogging during the filtration steps. With increasing agitation, higher recovery efficiencies can be achieved indicating that this method of cell detachment has potential for large volume processes

An energy efficient power controller switching methodology for an ambient healthcare network

A methodology for improved power controller switching in mobile Body Area Networks operating within the ambient healthcare environment is proposed. The work extends Anti-windup and Bumpless transfer results to provide a solution to the ambulatory networking problem that ensures sufficient biometric data can always be regenerated at the base station. The solution thereby guarantees satisfactory quality of service for healthcare providers. Compensation is provided for the nonlinear hardware constraints that are a typical feature of the type of network under consideration and graceful performance degradation in the face of hardware output power saturation is demonstrated, thus conserving network energy in an optimal fashion

Genome sequence of a gammaherpesvirus from a common bottlenose dolphin (Tursiops truncatus)

A herpesvirus genome was sequenced directly from a biopsy specimen of a rectal lesion from a female common bottlenose dolphin. This genome sequence comprises a unique region (161,235 bp) flanked by multiple copies of a terminal repeat (4,431 bp) and contains 72 putative genes. The virus was named common bottlenose dolphin gammaherpesvirus 1

Ariel - Volume 3 Number 6

Editors Richard J. Bonanno Robin A. Edwards Associate Editors Steven Ager Tom Williams Lay-out Editor Eugenia Miller Contributing Editors Paul Bialas Robert Breckenridge Lynne Porter David Jacoby Mike LeWitt Terry Burt Mark Pearlman Michael Leo Editors Emeritus Delvyn C. Case, Jr. Paul M. Fernhof

A preliminary study on how fatigue affects scoring average in professional darts

The purpose of this preliminary study is to identify signs of fatigue in specific muscle groups that in turn directly influence accuracy in professional darts. Electromyography (EMG) sensors are employed to monitor the electrical activity produced by skeletal muscles of the trunk and upper limb during throw. It is noted that the Flexor Pollicis Brevis muscle which controls the critical release action during throw shows signs of fatigue. This is accompanied by an inherent increase in mean integral EMG amplitude for a number of other throw related muscles indicating an attempt to maintain constant applied throwing force. A strong correlation is shown to exist between average score and decrease in mean integral ECG amplitude for the Flexor Pollicis Brevis