title: Isolation and characterisation of two chymotrypsins from Allocyttus niger (black oreo dory) viscera

authors: Krzyzosiak, J.

subjects: chymotrypsin

abstract: Two serine proteases from the viscera of deep-sea fish, black oreo dory (Allocyttus niger),were purified by hydrophobic, affinity, and cation exchange chromatography. They were designated as chymotrypsins on the basis of substrate specificity and susceptibility to inhibitors. The pH optima of chymotrypsin I and II were 8.6 and 10, respectively. Chymotrypsin II retained a remarkable 80% activity at pH 12.5. Thermal stability of both enzymes was enhanced in the presence of calcium ions. Both chymotrypsins were inhibited by high concentrations of substrate Suc-AAPF-NA.

text: Isolation and characterisation of two chymotrypsins from Allocyttus niger (black oreo dory) viscera Two serine proteases from the viscera of deep-sea fish, black oreo dory (Allocyttus niger),were purified by hydrophobic, affinity, and cation exchange chromatography. They were designated as chymotrypsins on the basis of substrate specificity and susceptibility to inhibitors. The pH optima of chymotrypsin I and II were 8.6 and 10, respectively. Chymotrypsin II retained a remarkable 80% activity at pH 12.5. Thermal stability of both enzymes was enhanced in the presence of calcium ions. Both chymotrypsins were inhibited by high concentrations of substrate Suc-AAPF-NA.

year: 1997

title: Behavioural Endocrinology of Breeding Adelie Penguins (Pygoscelis adeliae)

authors: Ninnes, Calum Edward

subjects: Adelie penguin

abstract: Measuring hormonal changes is vital for understanding how the social and physical environment influences behaviour, reproduction and survival. Various methods of hormone measurement exist, potentially explaining variation in results across studies; methods should be cross validated to ensure they correlate. I directly compare faecal and plasma hormone measurements (Chapter 2), and use the most suitable endocrine measure to test the Darling hypothesis (Chapter 3) - that breeding is hastened and synchronized in larger colonies due to increased social stimulation (mediated by the endocrine system).
Blood and faecal samples were simultaneously collected from individual Adelie penguins (Pygoscelis adeliae) for comparison, and assayed for testosterone and corticosterone (or their metabolites). Sex differences and variability within each measure, and correlation of values across measures were compared. For both hormones, plasma samples showed greater variation than faecal samples. Males had higher corticosterone levels than females, but the difference was only significant in faecal samples. Plasma testosterone, but not faecal testosterone, was significantly higher in males than females. Correlation between sample types was poor overall, and weaker in females than in males; perhaps because measures from plasma represent hormones that are both free and bound to globulins, whereas measures from faeces represent only the free portion. Faecal samples also represent a cumulative measure of hormones over time, as opposed to a plasma 'snapshot' concentration. Faecal sampling appears more suitable for assessing baseline hormone levels.
In the second study I examined, over two seasons, whether the timing of breeding varied with colony size; larger colonies present occupants with higher levels of social stimulation and are predicted to show earlier, more synchronous breeding. Baseline faecal hormone levels throughout the breeding season, and survival, were measured to investigate possible proximate and ultimate mechanisms for the results. The influence of environmental variability was examined, by relating the timing of breeding, survival, and endocrine changes to sea ice conditions. Colony size did not influence the timing or synchrony of breeding, survival, or hormone levels within years; perhaps because colonies in an Adelie rookery are not independent from the 'social environment' of adjacent colonies. Across years, synchrony in the smaller rookery was higher than in the larger rookery. The scale of these comparisons may exceed the applicability of the Darling hypothesis. Therefore, no support was found for the Darling hypothesis, at the colony or rookery level, in this species. Higher corticosterone metabolite and lower sex hormone levels in the first season correlated to later breeding and lower survival compared to the second season. This is likely due to the persistence of extensive sea ice conditions late into the first season.
Researchers should take care in selecting the most appropriate method of hormone measurement for their question. Future studies testing the Darling hypothesis must carefully select their definition of a colony (i.e. a truly isolated social unit) and the scale at which the hypothesis is tested. Combining endocrine measurements with behavioural, survival, and environmental information allows for a more comprehensive interpretation of animal ecology.

text: Behavioural Endocrinology of Breeding Adelie Penguins (Pygoscelis adeliae) Measuring hormonal changes is vital for understanding how the social and physical environment influences behaviour, reproduction and survival. Various methods of hormone measurement exist, potentially explaining variation in results across studies; methods should be cross validated to ensure they correlate. I directly compare faecal and plasma hormone measurements (Chapter 2), and use the most suitable endocrine measure to test the Darling hypothesis (Chapter 3) - that breeding is hastened and synchronized in larger colonies due to increased social stimulation (mediated by the endocrine system).
Blood and faecal samples were simultaneously collected from individual Adelie penguins (Pygoscelis adeliae) for comparison, and assayed for testosterone and corticosterone (or their metabolites). Sex differences and variability within each measure, and correlation of values across measures were compared. For both hormones, plasma samples showed greater variation than faecal samples. Males had higher corticosterone levels than females, but the difference was only significant in faecal samples. Plasma testosterone, but not faecal testosterone, was significantly higher in males than females. Correlation between sample types was poor overall, and weaker in females than in males; perhaps because measures from plasma represent hormones that are both free and bound to globulins, whereas measures from faeces represent only the free portion. Faecal samples also represent a cumulative measure of hormones over time, as opposed to a plasma 'snapshot' concentration. Faecal sampling appears more suitable for assessing baseline hormone levels.
In the second study I examined, over two seasons, whether the timing of breeding varied with colony size; larger colonies present occupants with higher levels of social stimulation and are predicted to show earlier, more synchronous breeding. Baseline faecal hormone levels throughout the breeding season, and survival, were measured to investigate possible proximate and ultimate mechanisms for the results. The influence of environmental variability was examined, by relating the timing of breeding, survival, and endocrine changes to sea ice conditions. Colony size did not influence the timing or synchrony of breeding, survival, or hormone levels within years; perhaps because colonies in an Adelie rookery are not independent from the 'social environment' of adjacent colonies. Across years, synchrony in the smaller rookery was higher than in the larger rookery. The scale of these comparisons may exceed the applicability of the Darling hypothesis. Therefore, no support was found for the Darling hypothesis, at the colony or rookery level, in this species. Higher corticosterone metabolite and lower sex hormone levels in the first season correlated to later breeding and lower survival compared to the second season. This is likely due to the persistence of extensive sea ice conditions late into the first season.
Researchers should take care in selecting the most appropriate method of hormone measurement for their question. Future studies testing the Darling hypothesis must carefully select their definition of a colony (i.e. a truly isolated social unit) and the scale at which the hypothesis is tested. Combining endocrine measurements with behavioural, survival, and environmental information allows for a more comprehensive interpretation of animal ecology.

year: 2008

title: The legacy of Ngatoroirangi: Maori customary use of geothermal resources

authors: Stokes, Evelyn

subjects: geothermal resources

abstract: Geothermal activity has always been regarded as a significant traditional resource among Maori communities of the Bay of Plenty, Rotorua and Taupo districts. The principal settlements of the tribes of Te Arawa, Ngati Tahu and Ngati Tuwharetoa were associated with geothermal areas. Outside the Taupo Volcanic Zone there were numerous other hot springs which were also highly valued by Maori. Areas of surface geothermal activity all have some traditions, cultural and historical associations for local tribes. Geothermal resources were used in various ways.

text: The legacy of Ngatoroirangi: Maori customary use of geothermal resources Geothermal activity has always been regarded as a significant traditional resource among Maori communities of the Bay of Plenty, Rotorua and Taupo districts. The principal settlements of the tribes of Te Arawa, Ngati Tahu and Ngati Tuwharetoa were associated with geothermal areas. Outside the Taupo Volcanic Zone there were numerous other hot springs which were also highly valued by Maori. Areas of surface geothermal activity all have some traditions, cultural and historical associations for local tribes. Geothermal resources were used in various ways.

year: 2000