title: Bovine blastocyst development depends on threonine catabolism

authors: Najafzadeh, V.

abstract: Increasing evidence suggests that pluripotency is a metabolically specialised state. In mouse, inner cell mass (ICM) cells and ICM-derived pluripotent stem cells (PSCs) critically depend on catabolising the amino acid threonine, while human PSCs require leucine, lysine, methionine and tryptophan. However, little is known about the specific amino acid requirements of putative pluripotent cells in bovine. We selectively depleted candidate essential amino acids (EAAs) from individually cultured bovine embryos to study their role in blastocyst development. Depleting one (-T, -M), two (-MT, -CM, -CT, -IL, -IK, -KL) or three (-CMT, -IKL) EAAs from chemically defined protein-free culture medium did not affect the morula-to-blastocyst transition from day five (D5) to D8 in vitro. By contrast, removing six (-CIKLMT, -FHRYVW), nine (+CMT, +IKL), eleven EAAs (+T, +M) or all twelve EAAs increasingly impaired blastocyst development. As no clear candidate emerged from this targeted screen, we focussed on threonine dehydrogenase (TDH), which catalyses threonine catabolism. TDH mRNA and protein was present at similar levels in trophectoderm (TE) and ICM but absent from several adult somatic tissues. We then treated morulae with an inhibitor (Qc1) that blocks TDH from catabolising threonine. Continuous exposure to Qc1 reduced total and high-quality blastocyst development from 37% to 26% and 18% to 8%, respectively (P<0.005). This was accompanied by ~2-fold decrease in ICM, TE and total cell numbers (P<0.005), which was due to increased autophagy (P<0.05). At the same time, ICM- (NANOG) and TE-restricted (KRT8) genes were up- and down-regulated, respectively (P<0.05). In summary, bovine blastocyst viability depended on TDH-mediated threonine catabolism. However, ICM and TE cells did not metabolically differ in this regard, highlighting species-specific connections between metabolism and pluripotency regulation in mouse vs cattle.

text: Bovine blastocyst development depends on threonine catabolism Increasing evidence suggests that pluripotency is a metabolically specialised state. In mouse, inner cell mass (ICM) cells and ICM-derived pluripotent stem cells (PSCs) critically depend on catabolising the amino acid threonine, while human PSCs require leucine, lysine, methionine and tryptophan. However, little is known about the specific amino acid requirements of putative pluripotent cells in bovine. We selectively depleted candidate essential amino acids (EAAs) from individually cultured bovine embryos to study their role in blastocyst development. Depleting one (-T, -M), two (-MT, -CM, -CT, -IL, -IK, -KL) or three (-CMT, -IKL) EAAs from chemically defined protein-free culture medium did not affect the morula-to-blastocyst transition from day five (D5) to D8 in vitro. By contrast, removing six (-CIKLMT, -FHRYVW), nine (+CMT, +IKL), eleven EAAs (+T, +M) or all twelve EAAs increasingly impaired blastocyst development. As no clear candidate emerged from this targeted screen, we focussed on threonine dehydrogenase (TDH), which catalyses threonine catabolism. TDH mRNA and protein was present at similar levels in trophectoderm (TE) and ICM but absent from several adult somatic tissues. We then treated morulae with an inhibitor (Qc1) that blocks TDH from catabolising threonine. Continuous exposure to Qc1 reduced total and high-quality blastocyst development from 37% to 26% and 18% to 8%, respectively (P<0.005). This was accompanied by ~2-fold decrease in ICM, TE and total cell numbers (P<0.005), which was due to increased autophagy (P<0.05). At the same time, ICM- (NANOG) and TE-restricted (KRT8) genes were up- and down-regulated, respectively (P<0.05). In summary, bovine blastocyst viability depended on TDH-mediated threonine catabolism. However, ICM and TE cells did not metabolically differ in this regard, highlighting species-specific connections between metabolism and pluripotency regulation in mouse vs cattle.

year: 2018

title: The Creation of Sustainable Development: What it means to CFOs in New Zealand

authors: Dimitrov, Dara

subjects: sustainability

abstract: Abstract currently unavailable

text: The Creation of Sustainable Development: What it means to CFOs in New Zealand Abstract currently unavailable

year: 2009

title: Analysis of multibeam sonar data for benthic habitat characterization of the Port of Tauranga, New Zealand.

authors: Boulay, Sebastien O. C.

subjects: Tauranga

abstract: Tauranga Harbour is a mesotidal lagoon located within the Bay of Plenty, New Zealand, and is subject to an ongoing maintenance dredging program to remove mud deposits coming from various sources in the catchment. At the southern end of the commercial port, the Tauranga Bridge Marina was built adjacent to the bridge causeway, with 500 floating concrete berths, enclosed by concrete floating breakwaters. It is proposed to convert these floating breakwaters into solid ones to stop waves entering the marina. This is expected to influence tidal circulation around the Tauranga bridge causeway, and potentially affect sedimentation and marine habitats. The region is an important source of "kai moana" (seafood) for local iwi, and is a source of juvenile shellfish for the large beds located on the flood tidal delta and surrounding channels.

This study investigates the impact of the successive harbour constructions on the local sedimentology. The overall goal of the mapping part of this project is to identify and locate the different seabed facies and features within the study site, which may be affected by the sediment transport potentially resulting from the past and future harbour developments. 

To investigate the impacts of the harbour modifications, a habitat-mapping survey using acoustic mapping techniques was undertaken in July and August 2011. The hydrographic survey was simultaneously performed using a multibeam echosounder (Kongsberg-Simrad EM3000) and a Starfish 452F sidescan sonar. The backscatter/imagery data from both systems was then used for habitat mapping, using a combination of Angular Response Analysis and image-based segmentation. An underwater camera survey and seabed sampling were also performed to ground-truth the morphologies identified from the acoustic backscatter analysis. The most recent habitat map was then compared to the previous studies to identify changes in response to the different modifications of the estuary.

text: Analysis of multibeam sonar data for benthic habitat characterization of the Port of Tauranga, New Zealand. Tauranga Harbour is a mesotidal lagoon located within the Bay of Plenty, New Zealand, and is subject to an ongoing maintenance dredging program to remove mud deposits coming from various sources in the catchment. At the southern end of the commercial port, the Tauranga Bridge Marina was built adjacent to the bridge causeway, with 500 floating concrete berths, enclosed by concrete floating breakwaters. It is proposed to convert these floating breakwaters into solid ones to stop waves entering the marina. This is expected to influence tidal circulation around the Tauranga bridge causeway, and potentially affect sedimentation and marine habitats. The region is an important source of "kai moana" (seafood) for local iwi, and is a source of juvenile shellfish for the large beds located on the flood tidal delta and surrounding channels.

This study investigates the impact of the successive harbour constructions on the local sedimentology. The overall goal of the mapping part of this project is to identify and locate the different seabed facies and features within the study site, which may be affected by the sediment transport potentially resulting from the past and future harbour developments. 

To investigate the impacts of the harbour modifications, a habitat-mapping survey using acoustic mapping techniques was undertaken in July and August 2011. The hydrographic survey was simultaneously performed using a multibeam echosounder (Kongsberg-Simrad EM3000) and a Starfish 452F sidescan sonar. The backscatter/imagery data from both systems was then used for habitat mapping, using a combination of Angular Response Analysis and image-based segmentation. An underwater camera survey and seabed sampling were also performed to ground-truth the morphologies identified from the acoustic backscatter analysis. The most recent habitat map was then compared to the previous studies to identify changes in response to the different modifications of the estuary.

year: 2012