title: Active-site- and substrate-specificity of Thermoanaerobium Tok6-B1 pullulanase.

authors: Plant, Adrian R.

subjects: biology

abstract: Thermoanaerobium Tok6-B1 pullulanase (EC 3.2.1.41) was active on alpha 1-6-glucosidic linkages of pullulan, amylopectin and glycogen and the alpha 1-4 linkages of amylose, amylopectin and glycogen but not of pullulan. Hydrolysis of short-chain-length malto-oligosaccharides (seven or fewer glucose residues) yielded maltose as product. Pullulan hydrolysis was pH-dependent and a plot of log(V/Km) versus pH implied a carboxy group with pKa 4.3 at the active site. Modification with 1-(3-dimethylaminopropyl)-3-ethylcarbodi-imide (EDAC) confirmed this view, and analysis of the order of reaction and inactivation kinetics suggested the presence of a single carboxy group at a catalytic centre of the active site. EDAC-mediated inhibition of pullulan alpha 1-6-bond hydrolysis was relieved by amylose or pullulan. Similarly both pullulan and amylose protected the activity directed at alpha 1-4 bonds of amylose from EDAC inhibition. When both amylose and pullulan were simultaneously present, the observed rate of product formation closely fitted a kinetic model in which both substrates were hydrolysed at the same active site.

text: Active-site- and substrate-specificity of Thermoanaerobium Tok6-B1 pullulanase. Thermoanaerobium Tok6-B1 pullulanase (EC 3.2.1.41) was active on alpha 1-6-glucosidic linkages of pullulan, amylopectin and glycogen and the alpha 1-4 linkages of amylose, amylopectin and glycogen but not of pullulan. Hydrolysis of short-chain-length malto-oligosaccharides (seven or fewer glucose residues) yielded maltose as product. Pullulan hydrolysis was pH-dependent and a plot of log(V/Km) versus pH implied a carboxy group with pKa 4.3 at the active site. Modification with 1-(3-dimethylaminopropyl)-3-ethylcarbodi-imide (EDAC) confirmed this view, and analysis of the order of reaction and inactivation kinetics suggested the presence of a single carboxy group at a catalytic centre of the active site. EDAC-mediated inhibition of pullulan alpha 1-6-bond hydrolysis was relieved by amylose or pullulan. Similarly both pullulan and amylose protected the activity directed at alpha 1-4 bonds of amylose from EDAC inhibition. When both amylose and pullulan were simultaneously present, the observed rate of product formation closely fitted a kinetic model in which both substrates were hydrolysed at the same active site.

year: 1987

title: Forecasting catastrophic stratovolcano collapse: A model based on Mount Taranaki, New Zealand

authors: Zernack, Anke V.

subjects: debris avalanches

abstract: Regular large-scale edifice collapse and regrowth is a common pattern during the long lifespans of andesitic stratovolcanoes worldwide. The >130 k.y. history of Mount Taranaki, New Zealand, is punctuated by at least 14 catastrophic collapses, producing debris avalanche deposits of 1 to >7.5 km³. The largest of these sudden events removed as much as one-third of the present-day equivalent cone. The resulting deposits show similar sedimentary and geomorphic features, suggesting similar proto-edifice characteristics, failure trigger mechanisms, and runout path conditions. Each collapse was followed by sustained renewed volcanism and cone regrowth, although there are no matching stepwise geochemical changes in the magma erupted; instead a stable, slowly evolving magmatic system has prevailed. Last Glacial climatic variations are also uncorrelated with the timing or magnitudes of edifice collapse. We demonstrate here that, if the magmatic composition erupted from stratovolcanoes is constant and basement geology conditions are stable, large-scale edifice collapse and the generation of catastrophic debris avalanches will be governed by the magma supply rate. Using a mass balance approach, a volume-frequency model can be applied to forecasting both the probable timing and volume of future edifice failure of such stratovolcanoes. In the Mount Taranaki case, the maximum potential size of a present collapse is estimated to be 7.9 km³, while the maximum interval before the next collapse is <16.2 k.y. The current annual collapse probability is ∼0.00018, with the most likely collapse being a small one (<2 km³).

text: Forecasting catastrophic stratovolcano collapse: A model based on Mount Taranaki, New Zealand Regular large-scale edifice collapse and regrowth is a common pattern during the long lifespans of andesitic stratovolcanoes worldwide. The >130 k.y. history of Mount Taranaki, New Zealand, is punctuated by at least 14 catastrophic collapses, producing debris avalanche deposits of 1 to >7.5 km³. The largest of these sudden events removed as much as one-third of the present-day equivalent cone. The resulting deposits show similar sedimentary and geomorphic features, suggesting similar proto-edifice characteristics, failure trigger mechanisms, and runout path conditions. Each collapse was followed by sustained renewed volcanism and cone regrowth, although there are no matching stepwise geochemical changes in the magma erupted; instead a stable, slowly evolving magmatic system has prevailed. Last Glacial climatic variations are also uncorrelated with the timing or magnitudes of edifice collapse. We demonstrate here that, if the magmatic composition erupted from stratovolcanoes is constant and basement geology conditions are stable, large-scale edifice collapse and the generation of catastrophic debris avalanches will be governed by the magma supply rate. Using a mass balance approach, a volume-frequency model can be applied to forecasting both the probable timing and volume of future edifice failure of such stratovolcanoes. In the Mount Taranaki case, the maximum potential size of a present collapse is estimated to be 7.9 km³, while the maximum interval before the next collapse is <16.2 k.y. The current annual collapse probability is ∼0.00018, with the most likely collapse being a small one (<2 km³).

year: 2012

title: The shift from the third way to neo-liberalism: An analysis of the 2010 amendments to the LGA

authors: Piercy, Gemma Louise

abstract: •	The New Zealand Third Way context
•	The 2002 Local Government Act (LGA)Case study: OhiwaHarbour Strategy
•	2010 and 2012 Amendments to the LGACase study: Social housing
•	Conclusion

text: The shift from the third way to neo-liberalism: An analysis of the 2010 amendments to the LGA •	The New Zealand Third Way context
•	The 2002 Local Government Act (LGA)Case study: OhiwaHarbour Strategy
•	2010 and 2012 Amendments to the LGACase study: Social housing
•	Conclusion

year: 2015