title: Identification, cloning, and functional characterization of the IL-1 receptor antagonist in the chicken reveal important differences between the Chicken and mammals

authors: Gibson, Mark S.

subjects: gene

abstract: The human IL-1 family contains 11 genes encoded at three separate loci. Nine, including IL-1R antagonist (IL-1RN), are present at a single locus on chromosome 2, whereas IL-18 and IL-33 lie on chromosomes 11 and 9, respectively. There are currently only two known orthologs in the chicken, IL-1β and IL-18, which are encoded on chromosomes 22 and 24, respectively. Two novel chicken IL-1 family sequences were identified from expressed sequence tag libraries, representing secretory and intracellular (icIL-1RN) structural variants of the IL-1RN gene, as seen in mammals. Two further putative splice variants (SVs) of both chicken IL-1RN (chIL-1RN) structural variants were also isolated. Alternative splicing of human icIL-1RN gives three different transcripts; there are no known SVs for human secretory IL-1RN. The chicken icIL-1RN SVs differ from those found in human icIL-1RN in terms of the rearrangements involved. In mammals, IL-1RN inhibits IL-1 activity by physically occupying the IL-1 type I receptor. Both full-length structural variants of chIL-1RN exhibited biological activity similar to their mammalian orthologs in a macrophage cell line bioassay. The four SVs, however, were not biologically active. The chicken IL-1 family is more fragmented in the genome than those of mammals, particularly in that the large multigene locus seen in mammals is absent. This suggests differential evolution of the family since the divergence of birds and mammals from a common ancestor, and makes determination of the full repertoire of chicken IL-1 family members more challenging.

text: Identification, cloning, and functional characterization of the IL-1 receptor antagonist in the chicken reveal important differences between the Chicken and mammals The human IL-1 family contains 11 genes encoded at three separate loci. Nine, including IL-1R antagonist (IL-1RN), are present at a single locus on chromosome 2, whereas IL-18 and IL-33 lie on chromosomes 11 and 9, respectively. There are currently only two known orthologs in the chicken, IL-1β and IL-18, which are encoded on chromosomes 22 and 24, respectively. Two novel chicken IL-1 family sequences were identified from expressed sequence tag libraries, representing secretory and intracellular (icIL-1RN) structural variants of the IL-1RN gene, as seen in mammals. Two further putative splice variants (SVs) of both chicken IL-1RN (chIL-1RN) structural variants were also isolated. Alternative splicing of human icIL-1RN gives three different transcripts; there are no known SVs for human secretory IL-1RN. The chicken icIL-1RN SVs differ from those found in human icIL-1RN in terms of the rearrangements involved. In mammals, IL-1RN inhibits IL-1 activity by physically occupying the IL-1 type I receptor. Both full-length structural variants of chIL-1RN exhibited biological activity similar to their mammalian orthologs in a macrophage cell line bioassay. The four SVs, however, were not biologically active. The chicken IL-1 family is more fragmented in the genome than those of mammals, particularly in that the large multigene locus seen in mammals is absent. This suggests differential evolution of the family since the divergence of birds and mammals from a common ancestor, and makes determination of the full repertoire of chicken IL-1 family members more challenging.

year: 2012

title: Development of a Rhizosheath Selection Tool for screening perennial ryegrass (Lolium perenne L.) for reduced root competition against white clover (Trifolium repens L.) for soil phosphorus

authors: Yeates, Rebecca Maree

subjects: Agriculture

abstract: Perennial ryegrass (Lolium perenne L.) outcompetes white clover (Trifolium repens L.) for soil phosphorus [P], resulting in higher P fertiliser rates to overcome the competition. Perennial ryegrass has long, dense root hairs compared to white clover, which increase the root contact with soil (soil exploration) and root surface area for P uptake. This study was conducted to test whether the selection of perennial ryegrass with reduced root hair length and density would reduce root competition for P with no detrimental effect on the perennial ryegrass growth. 
A Rhizosheath Selection Tool [RST] was developed to select ryegrass populations with contrasting root hair length and density. The RST protocol used rhizosheath traits (the width and coverage of soil adhered to the extracted root system) along with the total seedling weight to select two distinct ryegrass populations. The low rhizosheath population had shorter, sparser root hairs on seminal roots and sparser root hairs on adventitious roots than the high rhizosheath population.
The two populations were then grown at five soil P levels in a glasshouse experiment and demonstrated that the rhizosheath trait selection had no detrimental effect on growth. There were no significant differences between the two population’s dry weight (g) and P concentration (mg P g-1 dry weight). However there was evidence to indicate that the high rhizosheath population was sometimes more efficient at P uptake with a larger total P content (mg P). 
The two perennial ryegrass populations were then grown with companion white clover in Olsen P 12 and 19 mg L⁻¹ soil with partitions separating the shoot systems to avoid shoot competition for light. The low rhizosheath population had reduced root competition with the companion white clover. In Olsen P 12 mg L⁻¹ soil, more P was partitioned to the white clover than the ryegrass, measured by total P content (mg P), and achieved a greater dry weight (g) than when grown with the HRS ryegrass. In Olsen P 19 mg L⁻¹ soil there was no rhizosheath selection effect on white clover growth, possibly because of the reduced need for soil exploration by roots under the higher soil P availability. 
The findings from this study confirmed that the RST for the selection of a perennial ryegrass population with a reduced capacity for root competition against white clover for soil P is effective. Furthermore, the RST selection had no detrimental effect to the ryegrass growth. This research highlights the importance of root traits in forage plant breeding, and the potential environmental and economic benefits a low rhizosheath perennial ryegrass could have in New Zealand’s pastoral farming system.

text: Development of a Rhizosheath Selection Tool for screening perennial ryegrass (Lolium perenne L.) for reduced root competition against white clover (Trifolium repens L.) for soil phosphorus Perennial ryegrass (Lolium perenne L.) outcompetes white clover (Trifolium repens L.) for soil phosphorus [P], resulting in higher P fertiliser rates to overcome the competition. Perennial ryegrass has long, dense root hairs compared to white clover, which increase the root contact with soil (soil exploration) and root surface area for P uptake. This study was conducted to test whether the selection of perennial ryegrass with reduced root hair length and density would reduce root competition for P with no detrimental effect on the perennial ryegrass growth. 
A Rhizosheath Selection Tool [RST] was developed to select ryegrass populations with contrasting root hair length and density. The RST protocol used rhizosheath traits (the width and coverage of soil adhered to the extracted root system) along with the total seedling weight to select two distinct ryegrass populations. The low rhizosheath population had shorter, sparser root hairs on seminal roots and sparser root hairs on adventitious roots than the high rhizosheath population.
The two populations were then grown at five soil P levels in a glasshouse experiment and demonstrated that the rhizosheath trait selection had no detrimental effect on growth. There were no significant differences between the two population’s dry weight (g) and P concentration (mg P g-1 dry weight). However there was evidence to indicate that the high rhizosheath population was sometimes more efficient at P uptake with a larger total P content (mg P). 
The two perennial ryegrass populations were then grown with companion white clover in Olsen P 12 and 19 mg L⁻¹ soil with partitions separating the shoot systems to avoid shoot competition for light. The low rhizosheath population had reduced root competition with the companion white clover. In Olsen P 12 mg L⁻¹ soil, more P was partitioned to the white clover than the ryegrass, measured by total P content (mg P), and achieved a greater dry weight (g) than when grown with the HRS ryegrass. In Olsen P 19 mg L⁻¹ soil there was no rhizosheath selection effect on white clover growth, possibly because of the reduced need for soil exploration by roots under the higher soil P availability. 
The findings from this study confirmed that the RST for the selection of a perennial ryegrass population with a reduced capacity for root competition against white clover for soil P is effective. Furthermore, the RST selection had no detrimental effect to the ryegrass growth. This research highlights the importance of root traits in forage plant breeding, and the potential environmental and economic benefits a low rhizosheath perennial ryegrass could have in New Zealand’s pastoral farming system.

year: 2018

title: Estimated catchment loads of nitrogen and phosphorus to the Rotorua Te Arawa Lakes

authors: McBride, Chris G.

abstract: The Rotorua Te Arawa Lakes are central to the identity of their region, of immense historical and cultural importance, and provide ecosystem services that underpin biodiversity, conservation and socioeconomic aspirations of the community. The diversity of water quality in the lakes reflects their catchments, which are diverse in topography, hydrogeology and intensity of land use, ranging from the largely undeveloped land around lakes Tikitapu and Okataina, to highly developed forestry and pastoral land around lakes Rerewhakaaitu, Rotorua and Okaro. Lake water quality is strongly linked to nutrients received by each lake from surface flows and groundwater springs. It therefore follows that management of lake water quality requires a good understanding of nutrient loads derived from the landscape, as does the assessment or prediction of the in-lake effects of catchment-based management initiatives aimed at improving lake water quality.

text: Estimated catchment loads of nitrogen and phosphorus to the Rotorua Te Arawa Lakes The Rotorua Te Arawa Lakes are central to the identity of their region, of immense historical and cultural importance, and provide ecosystem services that underpin biodiversity, conservation and socioeconomic aspirations of the community. The diversity of water quality in the lakes reflects their catchments, which are diverse in topography, hydrogeology and intensity of land use, ranging from the largely undeveloped land around lakes Tikitapu and Okataina, to highly developed forestry and pastoral land around lakes Rerewhakaaitu, Rotorua and Okaro. Lake water quality is strongly linked to nutrients received by each lake from surface flows and groundwater springs. It therefore follows that management of lake water quality requires a good understanding of nutrient loads derived from the landscape, as does the assessment or prediction of the in-lake effects of catchment-based management initiatives aimed at improving lake water quality.

year: 2021