title: The purification and some properties of a stereospecific D-asparaginase from an extremely thermophilic bacterium, Thermus aquaticus.

authors: Guy, G.R.

subjects: biology

abstract: A specific D-asparaginase was isolated and crystallized from Thermus aquaticus strain T351. It is present in larger amounts than the L-asparaginase. The enzyme has a molecular weight of 60 000, an isoelectric point of 4.8 and a Km of 2 mM. It has 6 disulphide bonds/molecule, and a histidine residue at the active site. It is inhibited by keto acids and by high salt concentrations.

text: The purification and some properties of a stereospecific D-asparaginase from an extremely thermophilic bacterium, Thermus aquaticus. A specific D-asparaginase was isolated and crystallized from Thermus aquaticus strain T351. It is present in larger amounts than the L-asparaginase. The enzyme has a molecular weight of 60 000, an isoelectric point of 4.8 and a Km of 2 mM. It has 6 disulphide bonds/molecule, and a histidine residue at the active site. It is inhibited by keto acids and by high salt concentrations.

year: 1982

title: Time dependent properties of thermoplastic protein produced from bloodmeal with sodium sulphite as an anti-crosslinking agent

authors: Bier, James Michael

abstract: The aim of this research was to investigate how the time dependent mechanical behaviour of bloodmeal-based thermoplastic was affected by varying sodium sulphite content at two injection moulding temperatures (120°C at exit or 140°C at exit). Thermoplastic protein was prepared by extrusion with 2, 3 or 4g sodium sulphite (SS), 3g sodium dodecyl sulphate, 10 g urea, 20 g triethylene glycol and 40 g water per 100 g bloodmeal, then injection moulded into test specimens. Pull to break, creep and stress relaxation tests were performed on conditioned samples and glass transition temperature (Tg) was determined by dynamic mechanical analysis.
Ultimate tensile strength was 7.9, 7.6 and 5.6 MPa for samples moulded at 120°C and 7.6, 6.3 and 5.7 MPa when moulded at 140°C with 2, 3 and 4 g SS respectively. Experimental creep data was modelled with a 4 element model, consisting of a spring and dashpot in parallel, in series with an additional spring and dashpot. Plotting creep compliance versus time showed increasing chain mobility as SS content increased. Relaxation was modelled with the Struik equation for short-time experiments. Relaxation times were 530, 360 and 250 s with 2, 3 and 4 g SS respectively when moulded at the lower temperature. At 140°C, relaxation times were 440, 430 and 190 s for these SS contents. Tg was in the range 57-65°C (1 Hz peak in tanδ) for all samples, but was lowest for samples with 4 g SS.
These results show that both increased sodium sulphite and the higher moulding temperature increased chain mobility in the processed plastic.

text: Time dependent properties of thermoplastic protein produced from bloodmeal with sodium sulphite as an anti-crosslinking agent The aim of this research was to investigate how the time dependent mechanical behaviour of bloodmeal-based thermoplastic was affected by varying sodium sulphite content at two injection moulding temperatures (120°C at exit or 140°C at exit). Thermoplastic protein was prepared by extrusion with 2, 3 or 4g sodium sulphite (SS), 3g sodium dodecyl sulphate, 10 g urea, 20 g triethylene glycol and 40 g water per 100 g bloodmeal, then injection moulded into test specimens. Pull to break, creep and stress relaxation tests were performed on conditioned samples and glass transition temperature (Tg) was determined by dynamic mechanical analysis.
Ultimate tensile strength was 7.9, 7.6 and 5.6 MPa for samples moulded at 120°C and 7.6, 6.3 and 5.7 MPa when moulded at 140°C with 2, 3 and 4 g SS respectively. Experimental creep data was modelled with a 4 element model, consisting of a spring and dashpot in parallel, in series with an additional spring and dashpot. Plotting creep compliance versus time showed increasing chain mobility as SS content increased. Relaxation was modelled with the Struik equation for short-time experiments. Relaxation times were 530, 360 and 250 s with 2, 3 and 4 g SS respectively when moulded at the lower temperature. At 140°C, relaxation times were 440, 430 and 190 s for these SS contents. Tg was in the range 57-65°C (1 Hz peak in tanδ) for all samples, but was lowest for samples with 4 g SS.
These results show that both increased sodium sulphite and the higher moulding temperature increased chain mobility in the processed plastic.

year: 2012

title: Editorial: Special Issue: Ignored no longer: Emerging Indigenous researchers on Indigenous psychologies

authors: Groot, Shiloh Ann Maree

abstract: In this special issue, edited by Mohi, Bridgette, Shiloh, Pat and Darren, we showcase work conducted within several such Indigenous psychologies. This collection of papers from emerging Indigenous scholars reflect a vibrant, healthy and supportive research environment in which conversations relevant to Indigenous peoples are taking place, and where culturally diverse perspectives and methods are valued and accepted. Here, culture is not simply seen as an abstract set of concepts. Culture constitutes a field of human action, meaning making, and self-production. It is through culture that all people construct themselves and make sense of the world (Groot, Hodgetts, Nikora, & Leggat-Cook, 2011; Nikora, Rua, & Te Awekōtuku, 2007).

text: Editorial: Special Issue: Ignored no longer: Emerging Indigenous researchers on Indigenous psychologies In this special issue, edited by Mohi, Bridgette, Shiloh, Pat and Darren, we showcase work conducted within several such Indigenous psychologies. This collection of papers from emerging Indigenous scholars reflect a vibrant, healthy and supportive research environment in which conversations relevant to Indigenous peoples are taking place, and where culturally diverse perspectives and methods are valued and accepted. Here, culture is not simply seen as an abstract set of concepts. Culture constitutes a field of human action, meaning making, and self-production. It is through culture that all people construct themselves and make sense of the world (Groot, Hodgetts, Nikora, & Leggat-Cook, 2011; Nikora, Rua, & Te Awekōtuku, 2007).

year: 2012