11319 research outputs found
Sort by
Non-alcoholic fatty liver disease (NAFLD): Nutrition triggers and weight loss treatment strategies
No full textNon-alcoholic fatty liver disease (NAFLD) is an increasingly prevalent condition, and is often referred to as the hepatic manifestation of the metabolic syndrome. It affects up to 30% of adults and up to 60-70% of those with type 2 diabetes. Diet appears to be a critical factor in the pathogenesis, although what initiates the disease and causes progression is not well understood. In the absence of pharmacological therapy, diet and lifestyle modification aiming for 5-10% weight loss is recommended as the first line of treatment; however there is no particular recommended weight loss approach.
My PhD project consisted of two separate studies. The first, a crossover study, investigated possible dietary triggers of hepatic fatty acid accumulation, that is, dietary energy and macronutrients, in 12 healthy weight premenopausal women (Trigger Study); the effect of two 4-week hypercaloric (excess energy intake and weight gaining) diets and two 4-week isocaloric (similar calorific intake and weight maintaining) diets on liver fat, and markers of NAFLD were compared. The second 6-month study examined the feasibility of two weight-loss approaches in 20 overweight participants with confirmed NAFLD; a dietitian-guided partial meal replacement for 8 weeks followed by regular nurse follow-up, and a dietitian-guided ‘slow and steady’ weight loss approach based on evidence-based diabetes prevention and treatment dietary advice.
TRIGGER Study: What triggers non-alcoholic fatty liver disease – fat, carbohydrate or excess energy?
This crossover study compared the effect of two hypercaloric (excess energy intake personalised to produce a 3-5% bodyweight gain) diets with 35-40%TE from fat (15-25%TE from protein, 35-50%TE from carbohydrate) or 55-60%TE from refined carbohydrate (15-25%Te from protein, 15-30%TE from fat), with two isocaloric diets with the same macronutrient distributions as above, on liver fat and markers of NAFLD. Of the 16 healthy normal weight pre-menopausal New Zealand females aged 20-54 years randomised to one of the two diets, 12 women completed the full study. Participants were randomised to either the hypercaloric or isocaloric diet. The order in which they completed the two different 4-week diets containing different proportions of fat (35-40%) and refined carbohydrates (55-60%) was randomised. There was an 8-week washout period between the experimental diets. At the start and the end of each experimental diet period, liver fat was measured by Proton magnetic resonance spectroscopy (1H-MRS). Blood tests, including liver enzymes, and clinical measures (height, weight, waist circumference) were also taken at these times. Dietary intake was measured by multiple 3-day weighed food records (3d-WFR) and analysed using Kaiculator, a New Zealand based dietary assessment programme. Medians, ranges, interquartile ranges and means were calculated. Baseline dietary patterns included vegetarian, vegan, meat-eating, and high fat diets and median energy intake was 7844 kilojoules (kJ) (Interquartile range (IQR) 6474-8575kJ). The proportion of energy from each of the macronutrients varied between woment: protein from 11-21% with a median of 15%, carbohydrate varied from 24-63% with a median of 50%, and fat varied from 18-50% with a median of 36%. The 5 participants randomised to the hypercaloric diets gained 0.8-4.8% bodyweight, while bodyweight was maintained among those randomised to the isocaloric diets. Median liver fat content increased from 38.2% (IQR -3.2 – 54.1) (absolute median measures: 1.2% to 1.6%) with the hypercaloric diets, and a minimal change (median of 1.3% (IQR -20.3 – 15.0)) (absolute median measures: 1.4% to 1.4%) was observed with the isocaloric diets. The difference between the two groups was close to statistical significance (p=0.07). Both hypercaloric diets increased liver fat content; the high carbohydrate diet by 53.9% and the high fat diet by 35.3%, and there was no statistical difference between the two hypercaloric diets (p=0.14). The isocaloric diets had little effect on liver fat content. Alanine aminotransferase (ALT) levels increased during 80% of the hypercaloric diets, but only in 43% of the isocaloric diets. Participants were followed up after each experimental diet to ensure their weight returned to their pre-study usual weight, and their liver fat was also monitored to ensure it returned to the pre-study level, however this was only after the first experimental diet period and not the second due to cost.
INTERVENTION Study: Non-alcoholic fatty liver disease: The feasibility of two different weight loss dietary approaches
This 6-month feasibility study compared an 8-week low-calorie partial meal replacement diet followed by regular nurse ‘weigh-ins’ for 22 weeks (Optifast diet), and an intensive evidence-based nutritional approach for the treatment and prevention of diabetes (Lifestyle Over and Above Drugs in Diabetes (LOADD) diet). Twenty people aged 20-65 years with confirmed NAFLD were randomised to the Optifast diet (two meal replacements and one light meal daily for 4 weeks, then one meal replacement and two light meals daily for 4 weeks), or the LOADD diet (dietitian-guided weight loss using evidence-based nutrition guidelines for diabetes prevention and treatment). The frequency of intervention visits was the same for both diets. A questionnaire to update medical details, clinical measures, blood samples, a 3 day-Weighed Food Record (3d-WFR) and liver fat measured by H-MRS were completed at baseline, 8 weeks and 6 months. Median body mass index (BMI) at baseline was 35 kg/m² for both groups. Baseline dietary energy intake for the study population was 7209kJ, with 18% TE from protein, 35% TE from fat and 46% TE from carbohydrate. The participant retention for this study was high with only two participants withdrawing, and this was due to unrelated health issues. Both dietary approaches were acceptable to most participants with the exception of one participant finding the Optifast products unacceptable. Median weight loss was higher for the Optifast diet (4.1kg) than the LOADD diet (2.9kg) at 8 weeks (p = 0.047), but the same at 6 months (3.8kg) (p= 0.594). Weight gain at 6-months was observed for one Optifast diet and two LOADD diet participants. Liver fat decreased from 9.5% to 6.6% overall, with a 37.7% reduction in the Optifast diet and a 22.3% reduction in the LOADD diet. Both diets led to weight loss and liver fat reduction at 6 months.
Conclusion: The Trigger study showed that eating in excess of energy requirements increased bodyweight and liver fat content suggesting a prominent role of excess energy in the accumulation of liver fat, the first step in the pathogenesis of NAFLD. This also supports current recommendations to lose weight for the treatment of NAFLD. The INTERVENTION feasibility study demonstrated two potentially effective and acceptable weight loss strategies for NAFLD, both of which showed moderate weight losses over 6 months. These two strategies showed different weight loss patterns over 6 months but the overall weight loss at 6 months was similar. A larger and longer-term follow up study is warranted to assess the effectiveness and sustainability of these strategies
Indigenous and exotic : archaeozoology of the Te Hoe Shore whaling station, New Zealand
Full text linkFaunal analysis has long been a strength in the archaeology of prehistoric New Zealand, though its use in the interpretations of historic sites has been relatively recent. This thesis presents the results and interpretations of faunal analyses conducted on three early-mid, late prehistoric, and historic faunal assemblages from Te Hoe, the site of a nineteenth century shore whaling station on the North Island East Coast. Historic sources from the mid-nineteenth century are used to describe the shore whaling industry and lifestyle of whaling communities. Taxa utilised, habitats exploited, indigenous/exotic species focus and butchery unit analysis are used to provide a picture of resource use and dietary consumption at Te Hoe. These results are then compared between the three assemblages to examine temporal changes in the diet of the occupants at Te Hoe during these three periods. The historic faunal assemblage from Te Hoe is then compared with faunal assemblages from four other nineteenth century shore whaling station sites in New Zealand and Australia. This intersite comparison places the results from Te Hoe in temporal and spatial contexts. Finally, with the aid of historic resources, the emergence of the unique cultural identity of New Zealanders of European ancestry - Pakeha – is evidenced in the period of nineteenth century shore whalers, such as those that live at Te Hoe
Microbial master-manipulators of mending
Full text linkRecent work in our lab has uncovered an interesting connection between regeneration and the skin microbiome. Culturing tadpoles of the species Xenopus laevis in the antibiotic gentamicin has been shown to reduce the rate of successful tail regeneration following amputation. The addition of heat killed Escherichia coli to these gentamicin treated tadpoles rescued the successful regeneration phenotype. Furthermore, 16s rRNA sequencing showed that the skin microbiome of tadpoles in which regeneration was successful was distinct from those where regeneration failed. Successful regenerates correlated with high gram-negative skin microbiota levels, supporting the suggestion that gram-negative bacteria may play a role in regenerative success. This previous work also showed that activity in the NF-κB pathway increased upon amputation of the tadpole tail, indicating an immune response was triggered by the amputation process.
These discoveries led to the generation of a hypothesis: the exposure of host immune cells to skin microbes during tail amputation induces an immune response that is required to trigger regeneration in Xenopus laevis tadpoles. The primary immune receptor responsible for the recognition of gram-negative bacteria is Toll-like receptor 4 (Tlr4), which has evolved to recognise a major structural component in the outer membrane of gram-negative bacteria called Lipopolysaccharide (LPS). It is this interaction between host Tlr4 and bacterial LPS that may provide the link between skin microbiome and regeneration. This connection between skin microbiome and regenerative success of a complex appendage in a vertebrate system has not been published anywhere in the current literature and is incredibly exciting. Furthering our understanding in the rapidly evolving field of regeneration is crucial if we wish to one day apply this knowledge in a medical context
Social Capital, Resilience, and Smallholder Dairy Farmers: A Case Study of Four Communities in West Java, Indonesia
Full text linkSmallholder farmers are an important and interesting contributor to the economy, society and ecological relations of developing world countries. They are particularly interesting for both their potential economic contribution to regional and national wellbeing, but also their unique vulnerabilities to multiple pressures. This thesis examines how smallholder dairy farmers in Indonesia are resilient to these multiple pressures – particularly through the operation of high levels of social capital. The existing literature suggests that social capital has become an essential aspect for smallholders in the developing world to cope with and adapt to pressures and to respond to changes in economic, ecological and social dynamics. However, while social capital has been indicated as a key point of difference in the survival of smallholders, there has been a lack of research looking in more detail into the specific dynamics of social capital in supporting the resilience of smallholder dairy farmer communities. This knowledge gap has led the enquiry reported in this thesis to examine the role of social capital in one particular kind of case study: how smallholder dairy farmers in Indonesia manage to negotiate and sustain access to a common pool resource - agroforestry lands – which perform an essential role in supporting their dairy farming systems. The dynamics of access to lands held by completely different institutional actors, both in its initiation and its maintenance, provide a compelling case study of how social capital is central to the economic survival of smallholder farmers by facilitating and securing potential fragile ties and dependencies into an enduring resource base for dairy farming.
In addressing this gap, this thesis employs a theoretical framework that integrates the theory of social capital and community resilience. The framework deployed in this study characterizes both the way that social capital is embedded within social relations as well as the specific dynamics of social capital that are pivotal in establishing a resilient community. By employing qualitative methods, four smallholder dairy communities engaging with agroforestry practices in protected forest areas in West Java are explored as case studies in the dynamics of social capital that link smallholders to a vital external resource. From these case studies, empirical findings are derived which explore the operation and subtle dynamics of social capital that were indicated by the theoretical framework developed in the thesis.
This empirical results confirm that social capital has become a valuable asset to the survival of four communities in this study area. The theoretically-derived framework is used to characterize these dynamics into: structural social capital— social networks and formal rules, and cognitive social capital— trust and social norms. The results show that these two interconnected dimensions of social capital both facilitate collective actions through which the farmers can access various resources like fodder collection on protected forestry lands. The findings also identify specific dynamics of social capital in shaping the communities' ability to access agroforestry lands in three ways. Firstly, it is shown that social capital enables societies to have flexibility in developing resilience by providing affordable access to environmental capital. Secondly, social capital facilitates the communities to possess options for adapting to adversity by providing long-term access derived from a diversity of forest-origin resources and a secure land tenancy. Thirdly, social capital facilitates the learning capacity of the communities in deepening their awareness of sustainable forest management. These mechanisms have allowed the development of smallholder dairy farmers' resilience through the interplay between social capital and environmental capital (various forms of resources derived agroforestry lands), enabling the communities to accumulate and benefit from the resources and to mitigate forest-related natural disasters. In conclusion, the thesis both confirms the importance of social capital as a framework for understanding the resilience of smallholder farmers to multiple vulnerabilities. It also elaborates a particular framework for understanding the complex, specific, dynamics of social capital in enabling resilience in these communities. This conclusion informs particular policy recommendations which supersede the prior overly-simple focus on the development of economic capital or on specific technological interventions
What’s a Judge to Do? Allegations of Police Torture in China as Evidence in an English Court
Full text linkIn Shagang Shipping Co Ltd (in liq) v HNA Group Co Ltd [2020] UKSC 34, [2020] WLR(D) 488, the United Kingdom Supreme Court faced the vexing and politically fraught question of the admissibility of unproven but credible allegations of torture at the hands of Chinese police. This fascinating case required applying common law evidentiary rules with reference to background evidence relating to Chinese criminal law and procedure. The Supreme Court overruled the Court of Appeal on the relevance of unproven torture allegations, finding that although torture had not been proved, the torture allegations could be taken into account when assessing the reliability and weight of other evidence.Peer Reviewe
What is the impact of sugar-sweetened beverage taxes? A focus on the Pacific
No full textThe Pacific is facing a non-communicable disease (NCD) crisis driven by globalisation and trade, and in part by increased consumption of nutrient-poor energy-dense processed foods. Several jurisdictions in the region have introduced sugar-sweetened beverage (SSB) taxes with stated health goals. However, there are few reviews or evaluations of these policies and the potential health impacts remain unclear. The aim of this thesis was to evaluate the impact of SSB taxes in the Pacific from a public health perspective. Objectives were to: (1) summarise the international evidence from natural experiment studies and assess the average impacts of SSB taxes on purchasing and dietary consumption by meta-analysis; (2) identify and characterise the changes in SSB taxes from 2000-2019 in Pacific jurisdictions; (3) evaluate the impact of SSB tax changes in Tonga (in 2013, 2016 and 2017) and the Cook Islands (in 2008, 2012 and 2014) on price and imports; also manufacturing (Tonga, 2016), sales (Cook Islands, 2014), and how expenditure changes differ by household income (Tonga, 2013). Systematic review, meta-analysis and natural experiment studies, namely interrupted time series analyses and a before and after study of household expenditure, were carried out.
There was clear evidence on systematic review and meta-analysis of the international literature, that SSB taxes reduced purchasing or dietary consumption of taxed beverages, with a 10% reduction (95%CI: 5.0% to 14.7%) for an 10% equivalent SSB tax. There was a small non-significant substitution to untaxed beverages such as water. Heterogeneity of findings between jurisdictions suggested that tax design and contextual factors may have influenced the extent of tax effects.
Widespread use of SSB taxes in the Pacific was identified by a comprehensive review of SSB tax legislation. Three-quarters of Pacific jurisdictions had a SSB tax and more than a third of jurisdictions had increased SSB taxes by more than 20%, while several jurisdictions had also decreased taxes. There were some excellent examples of SSB tax design such as the 2017 tiered volumetric tax in Tonga that targeted a range of SSB categories. The majority of countries had taxes that favoured locally-manufactured beverages; most taxes were ad valorem or volumetric; only two taxes included sugar-sweetened fruit juices and earmarking was rare.
Interrupted time series analysis in Tonga found that all three excise tax increases were associated with increases in soft drink price (of an indicator product) and decreases in taxed beverage import volumes, compared to a counterfactual (and the majority were statistically significant). Manufacturing of bottled water and soft drinks also increased after the tax increase. Soft drink manufacturing increases, however, were dwarfed by the decrease in import volumes.
There was a significant decline in per-capita soft drink expenditure spanning the 2013 Tonga excise, and the decrease was greater in low-income households (although the difference was not statistically significant). Per-capita expenditure on bottled water increased dramatically and the increases were greater in high-income households (not significant).
Tariff increases in the Cook Islands were associated with mixed price changes and relatively small but non-significant declines in taxed beverage import volumes. Contextual changes appeared to have an important influence on study findings such as the revoke of invoice splitting and broad tax changes.
In summary, there is clear and ample evidence that SSB taxes are an effective policy for reducing purchasing and dietary intake of taxed beverages. Although the Pacific is not traditionally looked to for leadership in NCD prevention, there are some excellent examples and widespread use of SSB taxes in the region. SSB taxes in Tonga have likely contributed to a healthier diet, with significant declines in imports and a much smaller corresponding increase in local soft drink manufacturing. Many SSB tax policies could be strengthened to improve health benefits, eg, by equally taxing imported and manufactured SSBs, using volumetric or tiered taxes, targeting the full range of consumed SSBs, adjusting tax levels for inflation, improving home access to safe drinking water, and investing revenue in health and obesity prevention. Natural experiment methods were feasible, valuable and strengthened by a qualitative investigation of contextual data. Further research is needed to understand equity effects. SSB taxes, designed well, are a major tool and one of the most evidence-based prevention measures for addressing NCD risk factors in the Pacific and internationally
The health and wellbeing of New Zealand contemporary Vetrerans
No full textMulti System Illness conformed to the US Centers for Disease Control definition as ‘the presence of one or more chronic symptoms (for at least six months) from at least two of three categories namely fatigue, mood-cognition (symptoms of feeling depressed, difficulty remembering or concentrating, feeling moody, feeling anxious, trouble finding the right words or difficulty sleeping) and musculoskeletal (symptoms of joint pain, joint stiffness or muscle pain)’. The modified CDC questionnaire is a 63-item symptom checklist and formed the first section of the questionnaire. Participants had to indicate whether they had experienced one or more of the listed symptoms in the preceding month. Each symptom was further classified in terms of severity (mild, moderate, severe) and duration, lasting less than or greater than six months.
Three factors emerged from the analysis: factor 1 of an arthro-neuromuscular nature, factor 2 a cognitive domain, but factor 3 was psycho-physiological, so the overall factor pattern of New Zealand veterans is different from that reported elsewhere and there does appear to be a distinctive New Zealand pattern. In the MSI analysis, 54% of the veterans served in a war zone, and 28% had PTSD.
A regression analysis was used to see if either of these variables predicted the number of reported symptoms. Serving in a war zone did not, while having PTSD did, as did veteran age. On average (raw data), people with PTSD reported 20 symptoms while those who did not reported 9. The similar numbers for serving in a war zone were 13 and 12 respectively
Diplomatic Assurances as a Basis for Extradition to the People’s Republic of China.
No full textChina human rights experts have responded with scepticism to a “troubling precedent” handed down by the New Zealand Supreme Court in June (Donald Clarke “New Zealand’s Troubling Precedent for China Extradition”, Lawfare, 15 June 2021; Michael Caster “To the Supreme Court: Diplomatic Assurances from China are Meaningless” Stuff.co.nz (online ed, 12 June 2021). The decision, Minister of Justice v Kim [2021] NZSC 57, concerns Kyung Yup Kim — a South Korean citizen who moved to Aotearoa at the age of fourteen, more than thirty years ago. Kim is wanted on a murder charge in the People’s Republic of China (PRC), a capital offence in China; he is accused of killing Ms Peiyun Chen in Shanghai in 2009. New Zealand received an extradition request from the PRC in 2011, which included assurances that Kim would not be subject to the death penalty if convicted. The Minister of Justice has twice determined that Kim should be surrendered for extradition to the PRC under the Extradition Act 1999, but repeated legal challenges have so far prevented this step from taking place. Most recently, in 2019 the Court of Appeal had held that the Minister of Justice made multiple errors in assessing whether Kim could lawfully be surrendered (Kim v Minister of Justice [2019] NZCA 209; [2019] 3 NZLR 173; see Marcelo Rodriguez-Ferrere and Andrew Geddis “The New Zealand Court of Appeal on Extradition to the PRC”, UK Constitutional Law Blog, 24 June 2019). Notably, that decision was handed down by a bench that included Winkelmann CJ and Williams J, both of whom subsequently have been elevated to the Supreme Court (but, for obvious reasons, could not then sit on the current appeal).Peer Reviewe
Another one bites the microplastic! The impacts of microplastic exposure on the condition and anti-predator behaviour of coral reef fish
No full textThe increased use and rapid disposal of plastic products is leading to the widespread accumulation of plastic debris in marine ecosystems. As plastics breakdown, they are often mistaken as a food source leading to mechanically derived internal damage through abrasion, ulcers and digestive congestion resulting in a loss in body condition. In addition to direct ingestion of plastics is the potential threat of exposure to highly toxic chemicals that are used during the manufacturing of plastics. Exposure to these chemicals can induce adverse effects and maladaptive behavioural changes in organisms. However, little is known about the sub-lethal effects of microplastic exposure on the behaviour, olfactory ability and health of coral reef fishes. To investigate this, we exposed Spiny chromis damselfish (Acanthochromis polyacanthus) and Ambon damselfish (Pseudochromis amboinensis) recruits to a range of different plastic particles to quantify changes in behaviours important for successful recruitment. Using a standardised test to quantify escape and swimming performance, we found that when A. polyacanthus were exposed to plastic particles, the kinematic behaviours that underpin successful predator evasion were altered indicating that microplastic exposure could lead to higher predation rates. These changes were largely driven by an inability to recognise chemical alarm cues as an indication of risk. In addition to microplastic induced changes in anti-predator behaviour, biomarkers associated with oxidative damage, oxidative stress and antioxidant metabolism also indicated that microplastic exposure has a negative effect on the health of the fish. Additionally, A. polyacanthus and P. amboinensis exposed to DEHP microplastics, showed the greatest levels of oxidative stress and damage. Interestingly, predation rate of P. amboinensis individuals did not differ between microplastic treatments during mesocosm survival trials when exposed to predator fish P. fuscus. Overall, these changes suggest that microplastic pollution on coral reefs could have potential ecological ramifications in coral reef ecosystems
Portrait of a marine invertebrate: Cellaria Ellis & Solander 1786 (Cellariidae: Cheilostomata: Bryozoa)
No full textDue to their rich fossil record, bryozoans have been mainly studied by palaeontologists. There is still a surprisingly large gap of knowledge regarding living bryozoans, such as: ecological niches and preferences, growth, calcification processes and even their natural food sources. This thesis is designed to address some of these issues by establishing and examining a widespread, morphologically distinct and heavily calcified bryozoan genus Cellaria through a multidisciplinary approach, aiming to create strong foundations for its use as a model organism.
The Zealandian region is the perfect place to study this world-wide genus. It holds the highest diversity of Cellaria species in the world, with three described and 11 hitherto undescribed living species. Cellaria immersa and C. tenuirostris are the most dominant in the southern Zealandian region; we have described a fauna of 14 species altogether. These species are not randomly distributed. Here we used Cellaria specimens recorded in the years 1911–2018 together with specimens stored in collections from Southern New Zealand, identified them to species level, and combined their metadata with that in the published literature to provide a database for analysis. Distributional data were mapped and assessed in relation to environmental factors: surface chlorophyll-a, sea-surface and seafloor temperature, and substratum type. Cellaria species mostly occur at sites with relatively low productivity (0.10–0.99 mg/m3) and relatively high seafloor temperatures (13–14 °C). Sand was identified as the main textural component of the substratum where Cellaria was found. This ability of Cellaria species to colonize soft sediments is of high ecological importance in mid-shelf environments where hard substrata are uncommon. The associated bryozoan fauna identified comprises common elements of bryozoan assemblages and their reef formations around the world.
We described here seven new species: C. calculosa n. sp., C. curiosa n. sp., C. gracillima n. sp., C. major n. sp., C. spatulifera n. sp., C. stenorhyncha n. sp. and C. macricula n. sp. previously misidentified as C. humilis Moyano, 1983. Four additional species are left in open nomenclature since not enough key taxonomic characteristics were observed to define them as new. The new species described challenge conventional diagnoses of the genus Cellaria by extending the morphological characters of the global fauna of ‘Cellaria sensu lato’.
A potentially long-lived organism with a calcified skeleton, such as C. immersa, is likely to be of ecological significance. Ecological influences over time can be observed by investigating the growth (and calcification). However, the validity of the methods used to measure growth in bryozoans is debated. Naturally, the best way for measuring the true growth rate of bryozoans in culture is to first understand their growth in their natural environment. Therefore, we assessed a field experimental design for measuring in situ growth of heavily calcified bryozoans in the open ocean by using the mark-recapture method, representing the deepest known deployment to date. Twenty living colonies of C. immersa were collected and subsequently marked and deployed on the Otago shelf at 56 m depth for three months in the Austral summer (November–February). Due to high hydrodynamic activity only two colonies were alive at the time of collection. Although the data collected are not enough to be compared with confidence with other species, they do provide the first insight on the growth of C. immersa. The average growth of the internodes was 0.97±0.84 mm/year, indicating that some colonies of C. immersa may be at least 40 years old. Notwithstanding the challenges related to such a field experiment, this study succeeded in developing a robust and reproducible experimental set up for in situ growth experiments of heavily-calcified deep-water bryozoans.
Further, we explored the gene expression during the growth and calcification in C. immersa. A de novo transcriptome assembly was conducted from specimens collected off Otago, at 90 m depth. Differential expression analysis was carried out in order to identify genes that are expressed at a higher level in the different parts of the colonies; young distal and old proximal zooids of the colonies. The idea behind this is that young zooids will be growing and calcifying at a higher rate compared to the old zooids. The assembly resulted in a set of 21,219 transcripts of which 11,148 had function predicted by protein similarity against a range of databases. Over 50 proteins were identified as candidates involved in the biomineralization process and skeletal resorption in C. immersa. This is the first such study on a heavily calcified species from the phylum Bryozoa, thus significantly increasing the amount of genomic data for C. immersa but also for the phylum.
The culmination of this research combines the information gathered from all the previous questions together, to understand the genus Cellaria and its full potential as a model organism for bryozoans. The New Zealand region holds the highest species diversity of Cellaria sensu lato in the world, revealing unique morphological characteristics and ecological preferences that can contribute to future ecological analyses using Cellaria species globally, but also to be used as key elements for other bryozoan faunas. The field experiment represents the deepest deployment to date, and it outlines an experimental design which is robust, reusable and easily reproducible with the capacity to be applied anywhere in the world. The establishment of such an experimental set-up will enable us to shed some light into the life-span of heavily-calcified and ecologically-important shelf bryozoan species. Finally, the transcriptome analysis provides unprecedented new data for the phylum as regards perhaps the most salient feature of marine bryozoans, production of their well-calcified skeleton. These data provide a resource for current and future studies on C. immersa but also for other heavily calcified bryozoans. While it is, of course, impossible to cover everything in a single study, this thesis has succeeded in filling some key gaps in our knowledge about the genus Cellaria. This “portrait of a bryozoan” approach is unusual in its holistic approach, since no other single bryozoan genus has been the core of such a multidisciplinary study in last 50 years