title: Chemoecological investigations of predator-prey relationships in New Zealand nudibranchs for the discovery of new natural products

authors: Gris, Lauren

abstract: This study describes chemical ecology investigations of predator-prey relationships in New Zealand nudibranchs for the discovery of new natural products. Three predator-prey relationships were established, and twenty secondary metabolites were isolated and characterised from various New Zealand marine organisms, including five new compounds.
Predator-prey relationships were established for three nudibranch species, Polycera hedgpethi, Ceratosoma amoenum and Goniobranchus aureomarginatus by means of field studies and laboratory-based feeding-choice experiments. Results indicated that P. hedgpethi prefers the bryozoan Bugula neritina, while C. amoenum and G. aureomarginatus prefer feeding on the marine sponges Dysidea teawnui and Dictyodendrilla cf. dendyi, respectively. For two of the predator-prey relationships, common metabolites were found in both predator and prey. As such, Dysidea teawanui and C. amoenum both contain a sterol peroxide, while G. aureomarginatus and D. cf. dendyi both contain dictyodendrins C (209) and F (212). 
P. hedgpethi and B. neritina specimens were also chemically investigated but common metabolites were not found. Additionally, three nudibranch species, Dendrodoris krusensternii, Dendrodoris nigra and Aphelodoris luctuosa, were chemically investigated and yielded a range of secondary metabolites previously reported from marine invertebrates. A polymeric 3-alkyl pyridinium salt (146) was found in high concentration within A. luctuosa and its eggs. Moreover, an endemic bryozoan, Amathia gracei, was chemically investigated and yielded a known brominated alkaloid.
Investigation of G. aureomarginatus samples by LC-MS screening, to determine metabolite distribution and any ecological role of the compounds isolated, indicated that dictyodendrins C (209) and F (212) were present in the digestive glands, while a norditerpene, gracilin was only present in the mantle. Quantitative NMR spectroscopy indicated that the polymeric 3-alkyl pyridinium salt (146) was present in higher concentration in the mantle of Aphelodoris luctuosa, consistent with a defensive purpose and with its presence in high concentration within the egg masses of A. luctuosa. Morphological analysis revealed oxea spicules within the digestive gland of Aphelodoris luctuosa, suggesting that it is possibly feeding on haplosclerid sponges. 
An additional seven known polyaromatic alkaloids and five new sulphated denigrins alkaloids, denigrins H-L (262-266) were isolated and characterised from the sponge D. cf. dendyi by means of NMR spectroscopy and HR-ESI-MS guided isolation. The new and known metabolites isolated in this research were assessed in a general cytotoxicity assay against HeLa cells. Results indicated that the compounds were not particularly active (IC50 > 57 µM).

text: Chemoecological investigations of predator-prey relationships in New Zealand nudibranchs for the discovery of new natural products This study describes chemical ecology investigations of predator-prey relationships in New Zealand nudibranchs for the discovery of new natural products. Three predator-prey relationships were established, and twenty secondary metabolites were isolated and characterised from various New Zealand marine organisms, including five new compounds.
Predator-prey relationships were established for three nudibranch species, Polycera hedgpethi, Ceratosoma amoenum and Goniobranchus aureomarginatus by means of field studies and laboratory-based feeding-choice experiments. Results indicated that P. hedgpethi prefers the bryozoan Bugula neritina, while C. amoenum and G. aureomarginatus prefer feeding on the marine sponges Dysidea teawnui and Dictyodendrilla cf. dendyi, respectively. For two of the predator-prey relationships, common metabolites were found in both predator and prey. As such, Dysidea teawanui and C. amoenum both contain a sterol peroxide, while G. aureomarginatus and D. cf. dendyi both contain dictyodendrins C (209) and F (212). 
P. hedgpethi and B. neritina specimens were also chemically investigated but common metabolites were not found. Additionally, three nudibranch species, Dendrodoris krusensternii, Dendrodoris nigra and Aphelodoris luctuosa, were chemically investigated and yielded a range of secondary metabolites previously reported from marine invertebrates. A polymeric 3-alkyl pyridinium salt (146) was found in high concentration within A. luctuosa and its eggs. Moreover, an endemic bryozoan, Amathia gracei, was chemically investigated and yielded a known brominated alkaloid.
Investigation of G. aureomarginatus samples by LC-MS screening, to determine metabolite distribution and any ecological role of the compounds isolated, indicated that dictyodendrins C (209) and F (212) were present in the digestive glands, while a norditerpene, gracilin was only present in the mantle. Quantitative NMR spectroscopy indicated that the polymeric 3-alkyl pyridinium salt (146) was present in higher concentration in the mantle of Aphelodoris luctuosa, consistent with a defensive purpose and with its presence in high concentration within the egg masses of A. luctuosa. Morphological analysis revealed oxea spicules within the digestive gland of Aphelodoris luctuosa, suggesting that it is possibly feeding on haplosclerid sponges. 
An additional seven known polyaromatic alkaloids and five new sulphated denigrins alkaloids, denigrins H-L (262-266) were isolated and characterised from the sponge D. cf. dendyi by means of NMR spectroscopy and HR-ESI-MS guided isolation. The new and known metabolites isolated in this research were assessed in a general cytotoxicity assay against HeLa cells. Results indicated that the compounds were not particularly active (IC50 > 57 µM).

year: 2025

title: The effects of heavy-sled sprint training on acceleration capabilities in female rugby sevens athletes: A pilot study

authors: Sella, Francesco Stefano

abstract: INTRODUCTION: Well-developed acceleration abilities are critical for performance in rugby sevens. In this pilot study, we investigated the effects of heavy-sled sprint training on acceleration in female rugby sevens athletes. METHODS: Eleven junior female rugby sevens athletes completed 3-weeks of resisted sprint training (5-30 m) with heavy sleds (30 to 85% of body mass). Acceleration performance and biomechanical outputs were computed pre- and post-intervention using the methods described by Samozino et al. (2016). Training-induced changes were calculated using effect size (ES) and magnitude-based inferences. Correlations (r) between changes in sprint performance and biomechanical outputs (pre-post changes, and at baseline) were calculated. RESULTS: Small improvements in 5 m and 10 m times, and changes in mechanical effectiveness of force application (RFmax), maximum power output (Pmax), and force-velocity slope (SFV) were observed (ES = 0.36-0.40). Very large to almost perfect correlations were found between changes in 5 m and 10 m times with changes in Pmax, theoretical maximal (horizontal) force (F0), RFmax, rate of decrease in mechanical effectiveness (DRF), and SFV (r = 0.85-0.96). Changes in 5 m and 10m times were also very largely to almost perfectly correlated with initial individual profiles (SFV, DRF, F0, and Pmax) (r = 0.73-0.91). DISCUSSION: Heavy-sled sprint training was likely to improve 5 m and 10 m times, maximum power, and sprint biomechanics. Changes in Pmax, F0, DRF, RFmax, and SFV explained over 72% of the variance associated with improvements in 5 m and 10 m times. Furthermore, retrospective analysis showed that the initial individual force-velocity profiles were associated with the magnitude of improvements in sprint characteristics. TAKE HOME MESSAGE: Heavy-sled sprint training is likely to increase acceleration capabilities over short distances in female rugby sevens athletes. Changes in defined biomechanical outputs, and individual force-velocity profiles appear to be associated with these improvements.

text: The effects of heavy-sled sprint training on acceleration capabilities in female rugby sevens athletes: A pilot study INTRODUCTION: Well-developed acceleration abilities are critical for performance in rugby sevens. In this pilot study, we investigated the effects of heavy-sled sprint training on acceleration in female rugby sevens athletes. METHODS: Eleven junior female rugby sevens athletes completed 3-weeks of resisted sprint training (5-30 m) with heavy sleds (30 to 85% of body mass). Acceleration performance and biomechanical outputs were computed pre- and post-intervention using the methods described by Samozino et al. (2016). Training-induced changes were calculated using effect size (ES) and magnitude-based inferences. Correlations (r) between changes in sprint performance and biomechanical outputs (pre-post changes, and at baseline) were calculated. RESULTS: Small improvements in 5 m and 10 m times, and changes in mechanical effectiveness of force application (RFmax), maximum power output (Pmax), and force-velocity slope (SFV) were observed (ES = 0.36-0.40). Very large to almost perfect correlations were found between changes in 5 m and 10 m times with changes in Pmax, theoretical maximal (horizontal) force (F0), RFmax, rate of decrease in mechanical effectiveness (DRF), and SFV (r = 0.85-0.96). Changes in 5 m and 10m times were also very largely to almost perfectly correlated with initial individual profiles (SFV, DRF, F0, and Pmax) (r = 0.73-0.91). DISCUSSION: Heavy-sled sprint training was likely to improve 5 m and 10 m times, maximum power, and sprint biomechanics. Changes in Pmax, F0, DRF, RFmax, and SFV explained over 72% of the variance associated with improvements in 5 m and 10 m times. Furthermore, retrospective analysis showed that the initial individual force-velocity profiles were associated with the magnitude of improvements in sprint characteristics. TAKE HOME MESSAGE: Heavy-sled sprint training is likely to increase acceleration capabilities over short distances in female rugby sevens athletes. Changes in defined biomechanical outputs, and individual force-velocity profiles appear to be associated with these improvements.

year: 2018

title: Contextualising social enterprise in New Zealand

authors: Grant, Suzanne Lisa Parker

subjects: business enterprise

abstract: Purpose – Social enterprise in New Zealand is still in its infancy, with no recognised framework to inform knowledge of current or future developments. In this exploratory paper, the aim is to consider four influences which are shaping the development of social enterprise in New Zealand.

Design/methodology/approach – A critical-appreciative lens utilising Habermas' concepts of the lifeworld and system informs the consideration of these influences.

Findings – Four distinct cultural and historical influences are proposed as contributing to the scope and “flavour” of social enterprise developing in New Zealand: socio-cultural norms, e.g. “Kiwi ingenuity”; the neoliberal reforms initiated by successive governments during the 1980s; Crown settlements in relation to breaches of the principles of 1840 Treaty of Waitangi; New Zealanders' as international citizens.

Originality/value – The paper shows how feedback and dialogue across the sectors, at local, national and international levels, is now required to determine how other scholars, practitioners and policy makers perceive this proposed initial framework.

text: Contextualising social enterprise in New Zealand Purpose – Social enterprise in New Zealand is still in its infancy, with no recognised framework to inform knowledge of current or future developments. In this exploratory paper, the aim is to consider four influences which are shaping the development of social enterprise in New Zealand.

Design/methodology/approach – A critical-appreciative lens utilising Habermas' concepts of the lifeworld and system informs the consideration of these influences.

Findings – Four distinct cultural and historical influences are proposed as contributing to the scope and “flavour” of social enterprise developing in New Zealand: socio-cultural norms, e.g. “Kiwi ingenuity”; the neoliberal reforms initiated by successive governments during the 1980s; Crown settlements in relation to breaches of the principles of 1840 Treaty of Waitangi; New Zealanders' as international citizens.

Originality/value – The paper shows how feedback and dialogue across the sectors, at local, national and international levels, is now required to determine how other scholars, practitioners and policy makers perceive this proposed initial framework.

year: 2008