Michael A Packer

Michael A Packer
Cawthron Institute | CI · Aquaculture

BSc, MSc, PhD

About

51
Publications
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2,415
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Publications

Publications (51)
Article
Fucoxanthin is a carotenoid in algae with purported beneficial health-related properties including antioxidant, anti-photoaging, anti-metastasis, anti-hypertensive activity and more. These properties give fucoxanthin the potential to be used in cosmetic, dietary, and medicinal applications. This study evaluates the use of deep eutectic solvents (DE...
Article
Full-text available
Seaweeds have a long history of use as both food and medicine, especially in Asian cultures. Moreover, there is growing interest in the use of seaweed ingredients and bioactive compounds in pharmaceutical and nutraceutical products. One ailment that seaweed bioactive compounds may impact is hypertension caused by the enzyme Angiotensin Converting E...
Article
The agricultural production of ruminants is responsible for 24% of global methane emissions, contributing 39% of emissions of this greenhouse gas from the agricultural sector. Strategies to mitigate ruminant methanogenesis include the use of methanogen inhibitors. For example, the seaweeds Asparagopsis taxiformis and Asparagopsis armata included at...
Article
Aquaculture is a global scale industry providing sustainable production of protein-rich foods required to feed the growing world population. Microalgae cultivation in aquaculture bioreactors can exude extracellular polymeric substances leading to biofouling of infrastructure and increased disease risk. A structure–behaviour relationship was develop...
Article
Full-text available
Seaweeds have a long history of use as food, as flavouring agents, and find use in traditional folk medicine. Seaweed products range from food, feed, and dietary supplements to pharmaceuticals, and from bioenergy intermediates to materials. At present, 98% of the seaweed required by the seaweed industry is provided by five genera and only ten speci...
Article
Microbial electrogenic behaviour is well characterised in prokaryotes, including the exo-electrogenic soil bacteria (‘metal breathers’) and cyanobacteria, some of which can perform a light-induced donation of electrons to electrochemical devices. Two main methods of electron donation are proposed in these organisms; mobile electron shuttles (redox...
Article
In bivalve hatcheries, microalgae production accounts for a large proportion of hatchery operation costs. A reliable supply of good quality algae is essential for optimal output. Two commercially important algal species, Tisochrysis lutea (T-Iso) and Chaetoceros calcitrans were grown in batch culture under optimal and high-pH conditions for 7 and 5...
Article
In order to determine if nitrous oxide (N2O) emissions could affect the sustainability of microalgae-based pond systems, N2O emissions were recorded from an outdoor 900 L pilot high rate algal pond (HRAP) fed primary wastewater over 1 year. The HRAP was mixed using a paddle wheel and operated at a hydraulic retention time (HRT) of 7.5–10 days. Dire...
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Nitrous oxide (N2O) emissions have been repeatedly observed during microalgal cultivation and from microalgae-based ecosystems such as eutrophic lakes. Various studies have unambiguously demonstrated N2O synthesis by axenic unialgal cultures and identified several potential microalgal N2O pathways. Based on these data, several studies have also rep...
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The therapeutic benefits of Greenshell™ mussel (GSM; Perna canaliculus) preparations have been studied using in vitro test systems, animal models, and human clinical trials focusing mainly on anti-inflammatory and anti-arthritic effects. Activity is thought to be linked to key active ingredients that include omega-3 polyunsaturated fatty acids, a v...
Article
Over the last decades, several studies have reported emissions of nitrous oxide (N2 O) from microalgae cultures and aquatic ecosystems characterized by a high level of algal activity (e.g. eutrophic lakes). As N2 O is a potent greenhouse gas (GHG) and an ozone depleting pollutant, these findings suggest that large scale microalgae cultivation (and...
Article
Biological photovoltaics (BPVs) are emerging as a potential sustainable energy-generating technology to convert solar energy into electrical energy. Although a great variety of photosynthetic biomaterials were studied in BPVs, cyanobacteria are considered as superior candidates because of their simpler physiology. To facilitate extracellular electr...
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Microbial fuel cells (MFCs) are bioelectrochemical systems (BESs) that exploit biological catalytic processes for the generation of electrical power or the accumulation of useful compounds. Photosynthetic MFCs (pMFCs) are those that utilise photosynthetic microorganisms, such as algae and cyanobacteria, to provide reducing power at the anode. A rep...
Article
The production of valuable metabolites from microalgae represents a potentially sustainable source of a range of products that can be difficult to synthesise directly. Microalgae respond to the dynamic and often subtly shifting growth environment in a complex way. The optimal conditions for growth can be quite different to those needed for optimal...
Article
A capture mechanism observed in a culture of the dinoflagellate Dinophysis acuta when preying on the ciliate Mesodinium rubrum (also sometimes referred to as Myrionecta rubra) is described. The dinoflagellate released cohesive clumps of mucilage into the culture media. When M. rubrum cells came into contact with this mucilage, they were immediately...
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The Cawthron Institute Culture Collection of Micro-algae (CICCM) is a unique, nationally and internationally significant collection of 450 strains of approximately 100 micro-algae and 50 cyanobacteria species, both living and cryopreserved. The collection comprises 13 taxonomic classes and underpins research into the ecology and taxonomy of the iso...
Chapter
Microalgae and seaweeds have a long history and increasingly important applications as both food ingredients and animal feed. The vast majority of algal species have yet to be evaluated for these applications. However, due to their extensive diversity, it is likely that they will lead to the discovery of many new algal products and processes in the...
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Full-text available
Studies on biological photovoltaics based on intact organisms are challenging and in most cases include diffusing mediators to facilitate electrochemical communication with electrodes. However, using such mediators is impractical. Instead, surface confined Os-polymers have been successfully used in electrochemical studies including oxidoreductases...
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For decades, the microalgae Isochrysis spp. have been widely utilised as a live feed in aquaculture practices. This species possesses a number of favourable characteristics, notably its long-chain omega-3 polyunsaturated fatty acid (LC n-3 PUFA) content; primarily docosahexaenoic acid (DHA, 22:6n-3). This article describes the lipid class content a...
Article
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Photosynthetic microbial fuel cells (PMFCs) are an emerging technology for renewable solar energy conversion. Major efforts have been made to explore the electrogenic activity of cyanobacteria, mostly using practically unsustainable reagents. Here we report on photocurrent generation (≈8.64 μA cm(-2)) from cyanobacteria immobilized on electrodes mo...
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This work describes the development of an easily constructed, cost-effective photosynthetic microbial fuel cell design with highly reproducible electrochemical characteristics that can be used to screen algae and cyanobacteria for photosynthetic electrogenic activity. It is especially suitable for benthic varieties, those that attach to surfaces. T...
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Strains of the chlorophyte genus Dunaliella were isolated from Dominion Salt NZ Ltd evaporation ponds at Lake Grassmere/Kapara Te Hau, New Zealand. Five halo-tolerant groups were characterised using morphology, molecular phylogenetic analysis and physiological response to varying culture conditions. Species identification based on morphological cha...
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Cyanobacterial mats are common in Antarctic lakes, ponds and on moist soils. The species comprising these mats have adapted to tolerate extreme conditions (e.g. high salinities and UV radiation, freezing and extended periods of darkness). In this study, cyanobacterial mats were collected from shallow melt-water ponds in Pyramid Trough in Southern V...
Article
Through their ability to directly transfer electrons to electrodes, Geobacter sp. are key organisms for microbial fuel cell technology. This study presents a simple method to reproducibly select Geobacter-dominated anode biofilms from a mixed inoculum of bacteria using graphite electrodes initially poised at -0.25, -0.36 and -0.42V vs. Ag/AgCl. The...
Article
The diatom Chaetoceros calcitrans is a microalgal species used as food for larva in aquaculture for many species worldwide. Chaetoceros calcitrans is an important source of omega 3 long chain (C ≥ 20) polyunsaturated fatty acids (n-3 LC PUFA), chiefly eicosapentaenoic acid (EPA, 20:5n-3). This article reports lipid content, lipid class composition...
Article
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Benthic species of algae and cyanobacteria (i.e., those that grow on surfaces), may provide potential advantages over planktonic species for some commercial-scale biotechnological applications. A multitude of different designs of photobioreactor (PBR) are available for growing planktonic species but to date there has been little research on PBR for...
Article
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The use of algae to capture carbon dioxide as a method for greenhouse gas mitigation is discussed. A small fraction of the sunlight energy that bathes Earth is captured by photosynthesis and drives most living systems. Life on Earth is carbon-based and the energy is used to fix atmospheric carbon dioxide into biological material (biomass), indeed f...
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Nitric oxide (NO) signaling is important for the regulation of hematopoiesis. However, the role of individual NO synthase (NOS) isoforms is unclear. Our results indicate that the neuronal NOS isoform (nNOS) regulates hematopoiesis in vitro and in vivo. nNOS is expressed in adult bone marrow and fetal liver and is enriched in stromal cells. There is...
Article
Nitric oxide (NO) has a profound role in the generation, differentiation, survival, and physiology of neurons. We have created a novel transgenic model to study the action of NO in the adult brain, in which the neuronal isoform of NO synthase (nNOS) is expressed under control of the promoter of the calcium-calmodulin multifunctional kinase IIalpha...
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Neural progenitor cells are widespread throughout the adult central nervous system but only give rise to neurons in specific loci. Negative regulators of neurogenesis have therefore been postulated, but none have yet been identified as subserving a significant role in the adult brain. Here we report that nitric oxide (NO) acts as an important negat...
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The New Zealand environment is low in selenium and iodine, and is therefore ideally suited for the study of these anionic trace elements. The aim of this study was to determine urinary excretion of selenium and iodine during pregnancy and postpartum as part of an investigation of the influence of pregnancy and lactation on selenium metabolism in wo...
Article
Mutations and deletions in mitochondrial DNA (mtDNA) lead to a number of human diseases characterized by neuromuscular degeneration. Accumulation of truncated mtDNA molecules (delta-mtDNA) lacking a specific 4977-bp fragment, the common deletion, leads to three related mtDNA diseases: Pearson's syndrome; Kearns-Sayre syndrome; and chronic progressi...
Article
1. Peroxynitrite is a short-lived and damaging oxidant that forms rapidly from the reaction of superoxide with nitric oxide. 2. In 1990, Joseph Beckman proposed that peroxynitrite contributed significantly to pathological oxidative stress in living tissues, and subsequent evidence strongly supports this proposal. 3. In this review, we outline the p...
Article
1.Peroxynitrite is a short-lived and damaging oxidant that forms rapidly from the reaction of superoxide with nitric oxide.2.In 1990, Joseph Beckman proposed that peroxynitrite contributed significantly to pathological oxidative stress in living tissues, and subsequent evidence strongly supports this proposal.3.In this review, we outline the proper...
Article
Full-text available
The mitochondrial respiratory chain is a major source of superoxide within cells. This superoxide reacts with nitric oxide to form the damaging oxidant peroxynitrite which may be a significant contributor to mitochondrial oxidative damage. One aspect of this mitochondrial oxidative damage is the induction of the mitochondrial permeability transitio...
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The aim of this study was to establish methodology for a survey of the iodine and selenium status of New Zealand residents, more specifically to investigate the correlation between fasting or random casual urine samples and 24 hour urines for iodine and selenium excretion. Sixty-two (31 M, 31 F) adults collected casual, fasting and 24 hour urine sa...
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The mitochondrial respiratory chain continually produces superoxide leading to high levels of mitochondrial oxidative stress. This oxidative damage has been attributed to the formation of hydroxyl radicals and hydrogen peroxide from superoxide. Alternatively, mitochondrial superoxide may react with nitric oxide forming the potent oxidant peroxynitr...
Article
Peroxynitrite is a biologically important oxidant that damages mitochondria in a number of ways. We investigated the interaction of peroxynitrite with the mitochondrial glutathione pool by measuring the formation of oxidised glutathione and glutathione-protein mixed disulfides in mitochondria exposed to either peroxynitrite or tert-butylhydroperoxi...
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Apoptosis may contribute significantly to cell death in neurodegenerative diseases such as Alzheimer's and Parkinson's Diseases. PC12 cells are a widely used model system for apoptosis in neuronal cells. We wish to investigate whether mitochondrial damage or selective degradation contributes to apoptosis in PC12 cells caused by a range of factors,...
Article
Full-text available
Nitric oxide reacts rapidly with superoxide to form the potent oxidant peroxynitrite. Mitochondria in vivo produce superoxide and in pathological situations the amount of superoxide produced increases, therefore in the presence of nitric oxide mitochondria will be a major site of peroxynitrite formation. Oxidative stress induces a Cyclosporin A-sen...
Article
The effect of the parkinsonian neurotoxin, 1-methyl-4-phenylpyridinium (MPP+) together with nitric oxide donors on mitochondrial calcium homeostasis and membrane potential was investigated. Simultaneous exposure of calcium-loaded mitochondria to MPP+ and nitric oxide donors led to Cyclosporin A-sensitive mitochondrial calcium efflux and depolarisat...
Article
Nitric oxide reacts rapidly with superoxide to form the potent oxidant peroxynitrite. Mitochondria in vivo produce superoxide and in pathological situations the amount of superoxide produced increases; therefore, in the presence of nitric oxide, mitochondria will be a major site of peroxynitrite formation. Oxidative stress induces cyclosporin-A-sen...
Article
Superoxide reacts with nitric oxide to form peroxynitrite, a potent oxidising agent which may contribute to tissue damage in pathological situations such as inflammation and ischaemia/reperfusion. One mechanism by which oxidative stress damages tissues is the induction of a specific Cyclosporin A-sensitive mitochondrial calcium efflux pathway. Here...
Article
Full-text available
A new method for the preparation of protoplasts from the marine macroalga Porphyra which is more simple, faster and efficient than previous procedures is described. This method involves the mechanical breakdown of the tissue to osmotically stable individual cells and groups of cells in pairs followed by treatment with a mixture of crude enzyme extr...

Questions

Question (1)
Question
Can anyone point to a handy table for a range of different microalgae & cyano's for rough calculations? I understand that conditions and factors resulting from these conditions will affect this, but I'm doing some rough calculations and others calibrations would suffice. Also interested for euglenoids too. Thanks, Mike

Projects

Project (1)
Project
Grow and secure shellfish aquaculture industry in New Zealand Support hatchery spat production by enabling selective breeding, optimizing hatchery technologies and microalgal production. Diversify emerging shellfish species portfolio