title: A visual discrimination task to identify judgement bias in hens (Gallus gallus domesticus).

authors: Buchanan, Nicky

subjects: judgement bias

abstract: This study aimed to investigate whether the use of a judgement bias task with differential reinforcement was suitable to assess emotional states (positive or negative affect) in domestic hens.  Six hens were trained to discriminate between a vertical and horizontal rectangle using an operant procedure with differential reinforcement to each stimulus in order to induce a positive or negative affect.  Three ambiguous rectangles were introduced at intermediate angles and responses to these and the two learned rectangles were used to measure for judgement bias.  Initial judgement bias probes measured response bias using three different foods as reinforcement; poultry pellets, wheat and puffed wheat in a one food magazine operant chamber.  The chamber was then modified from a single food magazine to a double food magazine allowing six different food combinations with the three foods and differing reinforcement periods.  Judgement bias probes measured response bias to the learned and ambiguous rectangles using combinations of each food type.  Overall response latencies revealed a consistent pattern across all six hens with the fastest response times to the vertical (positive) stimulus and slowest response times to the horizontal (negative) stimulus.  Results indicate that judgement bias was best measured and identified in the one food magazine chamber with four of the six hens consistently demonstrating positive affect and two hens demonstrating slight negative affect.  It was found that results varied in the double magazine chamber revealing both response bias and food preference.

text: A visual discrimination task to identify judgement bias in hens (Gallus gallus domesticus). This study aimed to investigate whether the use of a judgement bias task with differential reinforcement was suitable to assess emotional states (positive or negative affect) in domestic hens.  Six hens were trained to discriminate between a vertical and horizontal rectangle using an operant procedure with differential reinforcement to each stimulus in order to induce a positive or negative affect.  Three ambiguous rectangles were introduced at intermediate angles and responses to these and the two learned rectangles were used to measure for judgement bias.  Initial judgement bias probes measured response bias using three different foods as reinforcement; poultry pellets, wheat and puffed wheat in a one food magazine operant chamber.  The chamber was then modified from a single food magazine to a double food magazine allowing six different food combinations with the three foods and differing reinforcement periods.  Judgement bias probes measured response bias to the learned and ambiguous rectangles using combinations of each food type.  Overall response latencies revealed a consistent pattern across all six hens with the fastest response times to the vertical (positive) stimulus and slowest response times to the horizontal (negative) stimulus.  Results indicate that judgement bias was best measured and identified in the one food magazine chamber with four of the six hens consistently demonstrating positive affect and two hens demonstrating slight negative affect.  It was found that results varied in the double magazine chamber revealing both response bias and food preference.

year: 2016

title: The effects of allelic hinge variation in IgG3 antibodies on protein dynamics and effector functions

authors: Kuplich Barcellos, Marina

abstract: Antibodies play a crucial role in eliminating infections by recognising foreign antigens with high specificity and affinity. If a target is not directly neutralised, antibodies can mediate potent effector function responses by coordinating the recruitment of immune cells through their constant regions. These powerful immune functions are being widely explored in the form of IgG-based monoclonal antibody therapies for the treatment of infections, cancer, and autoimmune diseases. However, the antibody constant region exhibits significant genetic polymorphism, and new variants are rapidly being discovered by advances in genomic sequencing techniques. The documented effects of this diversity include differences in structural dynamics, thermal stability, and Fc-mediated effector functions among a number of antibody subclasses, including IgG1, IgG2, and IgG3. Some variants are reported to be a contributing factor to variability in the outcome of disease and responsiveness to vaccines in humans. The IgG3 subclass, in particular, displays striking differences in the antibody hinge region – responsible for connecting target binding with constant-region-mediated immune function. Here, exon duplications mean the hinge region can vary by as many as 45 amino acids in length. This work seeks to better understand some of the functional consequences of this unusual IgG3 variation. 

To assess the effects of allelic hinge variation on protein dynamics and effector functions, we have expressed a panel of seven anti-CD20 antibodies with unique constant region allele sequences from subclasses IgG1, IgG2, and IgG3. Sequence verified plasmids were used to express full-length antibodies in HEK293 cells at high purity. We first used small angle X-ray scattering (SAXS) to assess the variability in size and structural flexibility between the allelic variants and compared our data with previous research on the same variant panel with antiHER2 variable domain sequences. Following this structural analysis, we next undertook ADCC (antibody-dependent cellular cytotoxicity) and ADCP (antibody dependent cellular phagocytosis) assays to determine if differences in structural dynamics between the polymorphic variants could be linked to differences in effector function. These assays specifically used genome-engineered reporter cell lines to evaluate the ability of allelic variants to engage constant region binding FcyRIIIa and FcyRIIa Fc receptors, typically found on peripheral blood mononuclear cells. Activation was measured by quantifying the levels of luciferase expressed as a reporter.  

The findings provided in this study demonstrate that allelic variants with longer hinges have larger and more flexible structures and tend to present weaker ADCC and ADCP responses. The data presented here is the basis for future work on the influence of IgG constant region diversity on antibody structural dynamics and effector functions, which could contribute to improvements in the design of therapeutic antibodies.

text: The effects of allelic hinge variation in IgG3 antibodies on protein dynamics and effector functions Antibodies play a crucial role in eliminating infections by recognising foreign antigens with high specificity and affinity. If a target is not directly neutralised, antibodies can mediate potent effector function responses by coordinating the recruitment of immune cells through their constant regions. These powerful immune functions are being widely explored in the form of IgG-based monoclonal antibody therapies for the treatment of infections, cancer, and autoimmune diseases. However, the antibody constant region exhibits significant genetic polymorphism, and new variants are rapidly being discovered by advances in genomic sequencing techniques. The documented effects of this diversity include differences in structural dynamics, thermal stability, and Fc-mediated effector functions among a number of antibody subclasses, including IgG1, IgG2, and IgG3. Some variants are reported to be a contributing factor to variability in the outcome of disease and responsiveness to vaccines in humans. The IgG3 subclass, in particular, displays striking differences in the antibody hinge region – responsible for connecting target binding with constant-region-mediated immune function. Here, exon duplications mean the hinge region can vary by as many as 45 amino acids in length. This work seeks to better understand some of the functional consequences of this unusual IgG3 variation. 

To assess the effects of allelic hinge variation on protein dynamics and effector functions, we have expressed a panel of seven anti-CD20 antibodies with unique constant region allele sequences from subclasses IgG1, IgG2, and IgG3. Sequence verified plasmids were used to express full-length antibodies in HEK293 cells at high purity. We first used small angle X-ray scattering (SAXS) to assess the variability in size and structural flexibility between the allelic variants and compared our data with previous research on the same variant panel with antiHER2 variable domain sequences. Following this structural analysis, we next undertook ADCC (antibody-dependent cellular cytotoxicity) and ADCP (antibody dependent cellular phagocytosis) assays to determine if differences in structural dynamics between the polymorphic variants could be linked to differences in effector function. These assays specifically used genome-engineered reporter cell lines to evaluate the ability of allelic variants to engage constant region binding FcyRIIIa and FcyRIIa Fc receptors, typically found on peripheral blood mononuclear cells. Activation was measured by quantifying the levels of luciferase expressed as a reporter.  

The findings provided in this study demonstrate that allelic variants with longer hinges have larger and more flexible structures and tend to present weaker ADCC and ADCP responses. The data presented here is the basis for future work on the influence of IgG constant region diversity on antibody structural dynamics and effector functions, which could contribute to improvements in the design of therapeutic antibodies.

year: 2024

title: Alum dosing of Waitangi Stream: Biomonitoring of aluminium 2021-2023

authors: Tempero, Grant Wayne

abstract: Continuous alum dosing of the Waitangi Stream at Lake Rotoehu commenced in 2011 to reduce concentrations of dissolved reactive phosphorus in this inflow to the lake and improve water quality. The Bay of Plenty Regional Council contracted the University of Waikato to undertake monitoring of biota in the Waitangi Stream for potential impacts due to alum dosing. Macroinvertebrate community analysis and tissue aluminium concentrations in kōura (Paranephrops planifrons) and goldfish (Carassius auratus) have been undertaken annually since 2013 to determine the impacts and bioaccumulation of aluminium.

text: Alum dosing of Waitangi Stream: Biomonitoring of aluminium 2021-2023 Continuous alum dosing of the Waitangi Stream at Lake Rotoehu commenced in 2011 to reduce concentrations of dissolved reactive phosphorus in this inflow to the lake and improve water quality. The Bay of Plenty Regional Council contracted the University of Waikato to undertake monitoring of biota in the Waitangi Stream for potential impacts due to alum dosing. Macroinvertebrate community analysis and tissue aluminium concentrations in kōura (Paranephrops planifrons) and goldfish (Carassius auratus) have been undertaken annually since 2013 to determine the impacts and bioaccumulation of aluminium.

year: 2024