Browsing by Author "Morrison, Rachel M."
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- ItemExposure to bloom-like concentrations of two marine Synechococcus cyanobacteria (strains CC9311 and CC9902) differentially alters fish behaviour(2014) Hamilton, Trevor; Paz-Yepes, Javier; Morrison, Rachel M.; Palenik, Brian; Tresguerres, MartinCoastal California experiences large-scale blooms of Synechococcus cyanobacteria, which are predicted to become more prevalent by the end of the 21st century as a result of global climate change. This study investigated whether exposure to bloom-like concentrations of two Synechococcus strains, CC9311 and CC9902, alters fish behaviour. Black perch (Embiotoca jacksoni) were exposed to Synechococcus strain CC9311 or CC9902 (1.5 × 106 cells ml−1) or to control seawater in experimental aquaria for 3 days. Fish movement inside a testing arena was then recorded and analysed using video camera-based motion-tracking software. Compared with control fish, fish exposed to CC9311 demonstrated a significant preference for the dark zone of the tank in the light–dark test, which is an indication of increased anxiety. Furthermore, fish exposed to CC9311 also had a statistically significant decrease in velocity and increase in immobility and they meandered more in comparison to control fish. There was a similar trend in velocity, immobility and meandering in fish exposed to CC9902, but there were no significant differences in behaviour or locomotion between this group and control fish. Identical results were obtained with a second batch of fish. Additionally, in this second trial we also investigated whether fish would recover after a 3 day period in seawater without cyanobacteria. Indeed, there were no longer any significant differences in behaviour among treatments, demonstrating that the sp. CC9311-induced alteration of behaviour is reversible. These results demonstrate that blooms of specific marine Synechococcus strains can induce differential sublethal effects in fish, namely alterations light–dark preference behaviour and motility.
- ItemKinetic resolution and parallel kinetic resolution of methyl (±)-5-alkyl-cyclopentene-1-carboxylates for the asymmetric synthesis of 5-alkyl-cispentacin derivatives(2005) Davies, Stephen G.; Garner, A. Christopher; Long, Marcus J. C.; Morrison, Rachel M.; Roberts, Paul M.; Savory, Edward D.; Smith, Andrew D.; Sweet, Miles J.; Withey, Jonathan M.Conjugate addition of lithium dibenzylamide to methyl 5-isopropyl, 5-phenyl- and 5-tert-butyl-cyclopentene-1-carboxylates occurs with high levels of substrate control (>88% de), with preferential addition to the face of the cyclic α,β-unsaturated acceptor anti- to the stereodirecting 5-alkyl substituent. Treatment of a range of methyl (±)-5-alkyl-cyclopentene-1-carboxylates with both lithium (±)-N-benzyl-N-α-methylbenzylamide and lithium (±)-N-3,4-dimethoxybenzyl-N-α-methylbenzylamide indicates significant enantiorecognition in their mutual kinetic resolutions, with preferential addition anti- to the 5-alkyl substituent, giving the 1,2-syn-1,5-anti-arrangement (E >16) after enolate protonation anti- to the amino functionality. The kinetic resolution of a range of methyl (±)-5-alkyl-cyclopentene-1-carboxylates with lithium (S)-N-benzyl-N-α-methylbenzylamide, and their efficient parallel kinetic resolution with a pseudoenantiomeric mixture of lithium (S)-N-benzyl-N-α-methylbenzylamide and lithium (R)-N-3,4-dimethoxybenzyl-N-α-methylbenzylamide are also demonstrated, giving a range of 5-alkyl-cispentacin derivatives in >98% de and high ee after N-deprotection.
- ItemPreparation of methyl (1R,2S,5S)- and (1S,2R,5R)-2-amino-5-tert-butyl-cyclopentane-1-carboxylates by parallel kinetic resolution of methyl (RS)-5-tert-butyl-cyclopentene-1-carboxylate(2003) Davies, Stephen G.; Díez, David; El Hammouni, Mohamed M.; Garner, A. Christopher; Garrido, Narciso M. ; Long, Marcus J. C.; Morrison, Rachel M.; Smith, Andrew D.; Sweet, Miles J.; Withey, Jonathan M.Comparison of the kinetic and parallel kinetic resolutions of methyl (RS)-5-tert-butyl-cyclopentene-1-carboxylate allows for the efficient synthesis of both (1R,2S,5S)- and (1S,2R,5R)-enantiomers of methyl 2-amino-5-tert-butyl-cyclopentane-1-carboxylate.