title: Low dissolved inorganic nitrogen and increased heterocyte frequency: precursors to Anabaena planktonica blooms in a temperate, eutrophic reservoir

authors: Wood, Susanna A.

subjects: anabaena planktonica

abstract: The relationship between heterocyte frequency, water temperature, nutrient concentrations and densities of Anabaena planktonica was examined in monomictic, eutrophic Lower Karori Reservoir (max. depth 21 m, area 0.034 km2), Wellington, New Zealand. Anabaena planktonica formed blooms and strongly dominated the phytoplankton assemblage during summer. The development of blooms of A. planktonica was associated with the set-up of stratification and increases in surface water temperature, with the peak of the bloom almost synchronous with maximum water temperature. The annual peak in heterocyte frequency preceded the bloom and occurred during a period of intensifying stratification. At this time, there were sustained low concentrations of dissolved inorganic nitrogen (DIN: nitrate-N + ammonium-N) and the lowest ratios of DIN to soluble reactive phosphorus (SRP), though ratios of total nitrogen to total phosphorus (TN:TP) were more variable. The apparent increase in nitrogen fixation capacity, based on increased heterocyte frequency, appears to be an important prerequisite to bloom formation for A. planktonica in the Lower Karori Reservoir. Monitoring heterocyte frequency may be a useful predictor for the occurrence of blooms of heterocytous cyanobacteria in eutrophic lakes due to the asynchronous nature of development of nitrogen limitation, heterocytes and vegetative cells.

text: Low dissolved inorganic nitrogen and increased heterocyte frequency: precursors to Anabaena planktonica blooms in a temperate, eutrophic reservoir The relationship between heterocyte frequency, water temperature, nutrient concentrations and densities of Anabaena planktonica was examined in monomictic, eutrophic Lower Karori Reservoir (max. depth 21 m, area 0.034 km2), Wellington, New Zealand. Anabaena planktonica formed blooms and strongly dominated the phytoplankton assemblage during summer. The development of blooms of A. planktonica was associated with the set-up of stratification and increases in surface water temperature, with the peak of the bloom almost synchronous with maximum water temperature. The annual peak in heterocyte frequency preceded the bloom and occurred during a period of intensifying stratification. At this time, there were sustained low concentrations of dissolved inorganic nitrogen (DIN: nitrate-N + ammonium-N) and the lowest ratios of DIN to soluble reactive phosphorus (SRP), though ratios of total nitrogen to total phosphorus (TN:TP) were more variable. The apparent increase in nitrogen fixation capacity, based on increased heterocyte frequency, appears to be an important prerequisite to bloom formation for A. planktonica in the Lower Karori Reservoir. Monitoring heterocyte frequency may be a useful predictor for the occurrence of blooms of heterocytous cyanobacteria in eutrophic lakes due to the asynchronous nature of development of nitrogen limitation, heterocytes and vegetative cells.

year: 2010

title: Keratin and S100 calcium-binding proteins are major constituents of the bovine teat canal lining

authors: Smolenski, Grant A.

abstract: The bovine teat canal provides the first-line of defence against pathogenic bacteria infecting the mammary gland, yet the protein composition and host-defence functionality of the teat canal lining (TCL) are not well characterised. In this study, TCL collected from six healthy lactating dairy cows was subjected to two-dimensional electrophoresis (2-DE) and mass spectrometry. The abundance and location of selected identified proteins were determined by western blotting and fluorescence immunohistochemistry. The variability of abundance among individual cows was also investigated. Two dominant clusters of proteins were detected in the TCL, comprising members of the keratin and S100 families of proteins. The S100 proteins were localised to the teat canal keratinocytes and were particularly predominant in the cornified outermost layer of the teat canal epithelium. Significant between-animal variation in the abundance of the S100 proteins in the TCL was demonstrated. Four of the six identified S100 proteins have been reported to have antimicrobial activity, suggesting that the TCL has additional functionality beyond being a physical barrier to invading microorganisms. These findings provide new insights into understanding host-defence of the teat canal and resistance of cows to mastitis.

text: Keratin and S100 calcium-binding proteins are major constituents of the bovine teat canal lining The bovine teat canal provides the first-line of defence against pathogenic bacteria infecting the mammary gland, yet the protein composition and host-defence functionality of the teat canal lining (TCL) are not well characterised. In this study, TCL collected from six healthy lactating dairy cows was subjected to two-dimensional electrophoresis (2-DE) and mass spectrometry. The abundance and location of selected identified proteins were determined by western blotting and fluorescence immunohistochemistry. The variability of abundance among individual cows was also investigated. Two dominant clusters of proteins were detected in the TCL, comprising members of the keratin and S100 families of proteins. The S100 proteins were localised to the teat canal keratinocytes and were particularly predominant in the cornified outermost layer of the teat canal epithelium. Significant between-animal variation in the abundance of the S100 proteins in the TCL was demonstrated. Four of the six identified S100 proteins have been reported to have antimicrobial activity, suggesting that the TCL has additional functionality beyond being a physical barrier to invading microorganisms. These findings provide new insights into understanding host-defence of the teat canal and resistance of cows to mastitis.

year: 2015-09-25

title: Niupepa: A historical newspaper collection

authors: Apperley, Mark

abstract: Niupepa is a collection of 42 newspaper titles published in New Zealand from 1842-1933, comprising a total of 21,000 pages in 1,750 issues. This collection forms a unique historical record of the language of the indigenous Mãori people, the evolution of the written form of this language, and of events and developments during the formative colonial history of our country. Using the Greenstone software from the New Zealand Digital Library this collection is now publicly available with full-text search capability.

text: Niupepa: A historical newspaper collection Niupepa is a collection of 42 newspaper titles published in New Zealand from 1842-1933, comprising a total of 21,000 pages in 1,750 issues. This collection forms a unique historical record of the language of the indigenous Mãori people, the evolution of the written form of this language, and of events and developments during the formative colonial history of our country. Using the Greenstone software from the New Zealand Digital Library this collection is now publicly available with full-text search capability.

year: 2001-05-01