title: Miocene isotope zones, paleotemperatures, and carbon maxima events at intermediate water-depth, Site 593, Southwest Pacific

authors: Cooke, Penelope J.

subjects: Tasman Sea

abstract: Oxygen and carbon isotopic stratigraphies are presented from both benthic and planktic foraminifera for the late early Miocene to earliest Pliocene interval (c. 19–5 Ma) of intermediate water-depth DSDP Site 593 in the southern Tasman Sea. The benthic values are interpreted as recording Miocene Southern Component Intermediate Water, while the planktic species record the Miocene mode and surface water signals. Comparisons are made between temperate Site 593 and the intermediate-depth polar Site 747 in the southern Indian Ocean. Glacial Mi zones Mi1b–Mi6, representing extreme glacial events, are evident in both the Site 593 intermediate and surface water records. Miocene Southern Component Intermediate Water δ18O values are generally lighter than the Holocene equivalent (Antarctic Intermediate Water), indicating slightly warmer intermediate waters and/or less global ice volume. The benthic-planktic gradient is interpreted as indicating a less stratified Tasman Sea during the Miocene. The benthic δ13C record contains most of the global carbon maxima (CM) events, CM1–7 (CM1–6 = the Monterey Excursion). Like global deep-water records, the Tasman Sea intermediate water δ13C values indicate that most CM events correspond with Mi glacials, including Mi4 at Site 593, not reported previously. Intermediate waters play an important role in propagating climatic changes from the polar regions to the tropics, and the Site 593 dataset provides a full water column record of the structure of Miocene intermediate to surface watermasses prior to the modern situation.

text: Miocene isotope zones, paleotemperatures, and carbon maxima events at intermediate water-depth, Site 593, Southwest Pacific Oxygen and carbon isotopic stratigraphies are presented from both benthic and planktic foraminifera for the late early Miocene to earliest Pliocene interval (c. 19–5 Ma) of intermediate water-depth DSDP Site 593 in the southern Tasman Sea. The benthic values are interpreted as recording Miocene Southern Component Intermediate Water, while the planktic species record the Miocene mode and surface water signals. Comparisons are made between temperate Site 593 and the intermediate-depth polar Site 747 in the southern Indian Ocean. Glacial Mi zones Mi1b–Mi6, representing extreme glacial events, are evident in both the Site 593 intermediate and surface water records. Miocene Southern Component Intermediate Water δ18O values are generally lighter than the Holocene equivalent (Antarctic Intermediate Water), indicating slightly warmer intermediate waters and/or less global ice volume. The benthic-planktic gradient is interpreted as indicating a less stratified Tasman Sea during the Miocene. The benthic δ13C record contains most of the global carbon maxima (CM) events, CM1–7 (CM1–6 = the Monterey Excursion). Like global deep-water records, the Tasman Sea intermediate water δ13C values indicate that most CM events correspond with Mi glacials, including Mi4 at Site 593, not reported previously. Intermediate waters play an important role in propagating climatic changes from the polar regions to the tropics, and the Site 593 dataset provides a full water column record of the structure of Miocene intermediate to surface watermasses prior to the modern situation.

year: 2008

title: Quiescence induces epigenetic changes in bovine fibroblasts and improves their reprogramming into cloned embryos

authors: Kallingappa, Prasanna Kumar

subjects: Quiescence, Epigenetics, Reprogramming, Somatic cell nuclear transfer (SCNT), Histone Methylation, Histone Acetylation, Histone varients, DNA methylation, Polycomb group (PcG) proteins

abstract: Cloning by somatic cell nuclear transfer (SCNT) forces cells to lose their lineage-specific epigenetic marks and become totipotent again. This reprogramming process often results in epigenetic and transcriptional aberrations that compromise development. Development rates after SCNT can thus serve as a functional assay for genome-wide epigenetic reprogramming. Dolly the sheep, the first mammalian SCNT clone, was derived from a donor cell that was induced into quiescence by serum starvation. We hypothesized that quiescence alters the epigenetic status of donor cells and elevates their reprogrammability. In order to test this idea, we compared chromatin composition and cloning efficiency of serum-starved, quiescent (G₀), bovine fibroblasts vs non-starved, diploid G₁ controls. Mechanically synchronized G₁ cells were generated by mitotic shake-off and harvested within 3 h post-mitosis. Based on morphological assessment and EdU incorporation during continuous labeling, >93% of cells were captured in G₁.
Using quantitative confocal immunofluorescence microscopy and fluorometric ELISA, we show that G₀ fibroblasts were significantly hypomethylated at lysines (K) of histone 3 (H3), specifically H3K4me3, H3K9me2, H3K9me3 and H3K27me3, but not H3K9me1. Histone acetylation was reduced at H3K9 and H4K5, increased at H3K12 and remained unchanged at H3K16. G₀ cells also significantly reduced DNAme. In addition, they significantly down-regulated the nuclear abundance of RNA polymerase II, histone variant H2A.Z, as well as Polycomb group (PcG) proteins EED, SUZ12, PHC1 and RING2. Histone variant H3.3, PcG proteins EZH2 and histone deacetylase HDAC1 did not change compared to the G₁ controls. Following NT into metaphase-arrested oocytes, G₀ DNA condensed slower than that of G₁ cells, indicating a more relaxed chromatin configuration. After seven days of in vitro culture, H3K9me3, but not H3K4me3, H3K27me3, SUZ12 and RING2, remained hypomethylated in G₀- vs G₁-derived NT blastocysts, both in the inner cell mass and trophectoderm. Furthermore, G₀ donors significantly improved development into cloned blastocysts. In conclusion, quiescence induced long-term epigenetic changes, specifically H3K9me3 hypomethylation, that correlated with increased donor cell reprogrammability.

text: Quiescence induces epigenetic changes in bovine fibroblasts and improves their reprogramming into cloned embryos Cloning by somatic cell nuclear transfer (SCNT) forces cells to lose their lineage-specific epigenetic marks and become totipotent again. This reprogramming process often results in epigenetic and transcriptional aberrations that compromise development. Development rates after SCNT can thus serve as a functional assay for genome-wide epigenetic reprogramming. Dolly the sheep, the first mammalian SCNT clone, was derived from a donor cell that was induced into quiescence by serum starvation. We hypothesized that quiescence alters the epigenetic status of donor cells and elevates their reprogrammability. In order to test this idea, we compared chromatin composition and cloning efficiency of serum-starved, quiescent (G₀), bovine fibroblasts vs non-starved, diploid G₁ controls. Mechanically synchronized G₁ cells were generated by mitotic shake-off and harvested within 3 h post-mitosis. Based on morphological assessment and EdU incorporation during continuous labeling, >93% of cells were captured in G₁.
Using quantitative confocal immunofluorescence microscopy and fluorometric ELISA, we show that G₀ fibroblasts were significantly hypomethylated at lysines (K) of histone 3 (H3), specifically H3K4me3, H3K9me2, H3K9me3 and H3K27me3, but not H3K9me1. Histone acetylation was reduced at H3K9 and H4K5, increased at H3K12 and remained unchanged at H3K16. G₀ cells also significantly reduced DNAme. In addition, they significantly down-regulated the nuclear abundance of RNA polymerase II, histone variant H2A.Z, as well as Polycomb group (PcG) proteins EED, SUZ12, PHC1 and RING2. Histone variant H3.3, PcG proteins EZH2 and histone deacetylase HDAC1 did not change compared to the G₁ controls. Following NT into metaphase-arrested oocytes, G₀ DNA condensed slower than that of G₁ cells, indicating a more relaxed chromatin configuration. After seven days of in vitro culture, H3K9me3, but not H3K4me3, H3K27me3, SUZ12 and RING2, remained hypomethylated in G₀- vs G₁-derived NT blastocysts, both in the inner cell mass and trophectoderm. Furthermore, G₀ donors significantly improved development into cloned blastocysts. In conclusion, quiescence induced long-term epigenetic changes, specifically H3K9me3 hypomethylation, that correlated with increased donor cell reprogrammability.

year: 2013

title: Empirical analysis of Pacific, Māori and ethnic pay gaps in New Zealand

authors: Cochrane, William

abstract: A descriptive profile of the four ethnic groups, by gender, is provided to illustrate the heterogeneities across populations in terms of a number of variables grouped into the following categories: individual characteristics, educational attainment, region, household and job-related characteristics. The main empirical analysis involves estimation of the statistical contribution of observed factors (within each of the aforementioned categories) towards explaining the ethnic pay gaps. As this research is primarily aimed as an input towards the Pacific Pay Gap Inquiry being conducted by the Human Rights Commission, we focus our summary of the key findings on the Pacific – European pay gap.
This includes variables on permanent contract status, an indicator if in part-time work, occupation, and industry. These results are therefore likely an indication of the strong role of occupational segregation in the labour market. An additional factor that had a relatively strong contribution to the pay gap, particularly for the Pacific – European female gap, was educational attainment. Overall, even after accounting for differences in job-related characteristics and educational attainment, amongst a number of other observed factors, it was still found that only 27 percent of the pay gap for Pacific males (relative to Europeans) could be explained; and the corresponding proportion for females was 39 percent. The remaining portion of the Pacific Pay Gap is likely to reflect a range of causes that cannot be quantified or disentangled in this analysis – such as not including other factors of importance as they weren’t observed in the data (for example, literacy proficiency or field of study for qualification attained); ethnic differences in preferences for non-wage components of the job; unconscious bias; and discrimination.

text: Empirical analysis of Pacific, Māori and ethnic pay gaps in New Zealand A descriptive profile of the four ethnic groups, by gender, is provided to illustrate the heterogeneities across populations in terms of a number of variables grouped into the following categories: individual characteristics, educational attainment, region, household and job-related characteristics. The main empirical analysis involves estimation of the statistical contribution of observed factors (within each of the aforementioned categories) towards explaining the ethnic pay gaps. As this research is primarily aimed as an input towards the Pacific Pay Gap Inquiry being conducted by the Human Rights Commission, we focus our summary of the key findings on the Pacific – European pay gap.
This includes variables on permanent contract status, an indicator if in part-time work, occupation, and industry. These results are therefore likely an indication of the strong role of occupational segregation in the labour market. An additional factor that had a relatively strong contribution to the pay gap, particularly for the Pacific – European female gap, was educational attainment. Overall, even after accounting for differences in job-related characteristics and educational attainment, amongst a number of other observed factors, it was still found that only 27 percent of the pay gap for Pacific males (relative to Europeans) could be explained; and the corresponding proportion for females was 39 percent. The remaining portion of the Pacific Pay Gap is likely to reflect a range of causes that cannot be quantified or disentangled in this analysis – such as not including other factors of importance as they weren’t observed in the data (for example, literacy proficiency or field of study for qualification attained); ethnic differences in preferences for non-wage components of the job; unconscious bias; and discrimination.

year: 2022-07