21 results on '"Ericson JA"'
Search Results
2. Lipid biochemistry and physiology of Antarctic krill (Euphausia superba) in the present day and under future ocean acidification scenarios
- Author
-
Ericson, JA
- Abstract
Antarctic krill (Euphausia superba, hereafter ‘krill’) are lipid-rich euphausiids with an important role in the Southern Ocean, including as the primary prey of Antarctic megafauna (whales, seals, penguins), fish, squid and seabirds. They contain high levels of nutritious long-chain (≥C\(_{20}\)) polyunsaturated fatty acids (LC-PUFA), specifically eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3). The sheer abundance of krill in the Southern Ocean means that the ecosystem is largely driven by energy derived from krill lipids. In addition to their ecological importance, a Scotia Sea krill fishery harvests krill, including for commercial use of their LC-PUFA. The existence of this year-round krill fishery provides a unique opportunity to collect krill samples for research over large spatial and temporal scales, which is unfeasible using scientific research vessels. In this thesis, fishery caught krill samples were used to investigate the fatty acid content and composition of krill, during all seasons and over consecutive years (2013 – 2016). This research (presented in Chapter 2) aimed to fill knowledge gaps on the seasonal diet of krill (particularly in winter) in the Scotia Sea region, using fatty acids as dietary biomarkers. Krill were primarily herbivorous in summer (higher levels of 20:5n-3 and 22:6n-3, and low 18:1n-9c/18:1n-7c ratios) and became more omnivorous from autumn to spring (increasing ratios of 18:1n-9c/18:1n-7c and percentages of Σ 20:1 + 22:1 isomers). Seasonal proportions of herbivory and omnivory differed between years, and fatty acid composition differed between fishing locations. Selected samples were also used to investigate the composition of fatty acids in the structural (phospholipids) and storage lipids (triacylglycerols) of krill (Chapter 3). Triacylglycerol fatty acids (thought to better represent recent diet), reflected omnivorous feeding with highest percentages of flagellate biomarkers (18:4n-3) occurring in summer, diatom biomarkers (16:1n-7c) from autumn-spring, and greater carnivory (higher Σ 20:1 + 22:1 and 18:1n-9c/18:1n-7c ratios) in autumn. Phospholipid fatty acids were less variable and were higher in the essential membrane fatty acids 20:5n-3 and 22:6n-3. Percentages of the major krill sterol, cholesterol, were significantly higher in winter and spring compared with summer and autumn. Results presented in Chapters 2 and 3 highlighted the dynamic nature of krill lipids, and the flexible diet of krill, which likely contributes to their huge biomass and success as one of the most abundant organisms on Earth. Because krill are so important in the Southern Ocean food web, any decreases in krill biomass could result in a major ecological regime shift. Very little is known about how climate change will affect krill. Increasing anthropogenic carbon dioxide (CO\(_2\)) emissions are causing ocean acidification, as absorption of atmospheric CO\(_2\) in seawater alters ocean chemistry. Ocean acidification increases mortality and negatively affects physiological functioning in some marine invertebrates, and is predicted to occur most rapidly at high latitudes. Long-term laboratory studies are needed to understand how keystone species such as krill may respond to predicted future pCO\(_2\) levels. A long term experiment was conducted to test whether rising ocean pCO\(_2\) is likely to impact krill physiology and biochemistry (Chapters 4 and 5). Adult krill were exposed to near-future ocean acidification (1000 – 2000 μatm pCO\(_2\)) for one year in the laboratory. Krill reared in near-future pCO\(_2\) conditions were able to survive, grow, store fat, mature, and maintain normal respiration rates. Haemolymph pH, lipid and fatty acid composition were also maintained at the same levels as krill in ambient pCO\(_2\) (400 μatm). Negative effects on physiology and lipid biochemistry were only observed in extreme pCO\(_2\) conditions (4000 μatm), which krill will not experience in the wild. These results place adult krill among the most resilient species in ocean acidification studies to date. In summary, results in this thesis highlight the remarkable adaptability of krill in a changing environment, from short-term seasonal or annual scales, to longer-term decadal scales. Their flexible phenotype may aid their survival in an ocean that is rapidly changing with increasing anthropogenic CO\(_2\) emissions. The data obtained in this thesis can be used for fisheries management to guide fishing activities, and in fisheries models to predict how krill biomass may be affected by climate change. Krill lipid energy fuels the Southern Ocean ecosystem and to date, lipid data has not been included in Antarctic ecosystem models. The large scale of lipid data in this study makes it ideal for inclusion in such models, and it has important implications for the health of the wider Southern Ocean ecosystem.
- Published
- 2019
- Full Text
- View/download PDF
3. Factores resilientes en docentes de la Unidad Educativa 'Mathius Josué Quintanilla Sierra' como recurso psicoemocional para afrontar las adversidades del entorno educativo actual
- Author
-
Ericson Jacinto Lucas Miranda and Anicia Katherine Tarazona Meza
- Subjects
resiliencia en docentes ,niveles de resiliencia ,educación ,factores resilientes ,adversidad ,Education (General) ,L7-991 ,History of education ,LA5-2396 ,Special aspects of education ,LC8-6691 ,Theory and practice of education ,LB5-3640 - Abstract
El presente artículo presenta una investigación que tuvo como objetivo determinar los factores resilientes en docentes de la Unidad Educativa Mathius Josué Quintanilla Sierra como recurso psicoemocional para afrontar las adversidades del entorno educativo actual. Metodológicamente se utilizó el método cuantitativo, enmarcada en un diseño exploratorio-descriptivo. Los sujetos de estudio fueron 25 docentes a los cuales se les aplicó el instrumento denominado la escala de Resiliencia SV-RES propuesto por el Dr. Saavedra y el Dr. Villalta, el cual permitió conocer los niveles de resiliencia de los docentes y los factores específicos que lo conforma. Se concluyó que los niveles de resiliencia de los maestros son altos, siendo el factor resiliente del Yo puedo el que prevalece en los docentes de la Unidad Educativa Matthias Josué Quintanilla Sierra, donde el factor resaltante y el que obtuvo una puntuación más alta es la afectividad, lo que determina las grandes habilidades positivas en las relaciones con los otros, lo cual ayuda a solucionar situaciones adversas.
- Published
- 2022
- Full Text
- View/download PDF
4. Composite depth of cure using four polymerization techniques
- Author
-
Ericson Janolio de Camargo, Eduardo Moreschi, Wagner Baseggio, Jaime Aparecido Cury, and Renata Corrêa Pascotto
- Subjects
Composite resins ,Cure ,Bisphenol A-Glycidyl Methacrylate ,Dentistry ,RK1-715 - Abstract
The light-curing technique is relevant to reduce the degree of polymerization shrinkage, improving clinical and esthetic success of composite resin restorations. OBJECTIVE: To evaluate in vitro the effect of four light-curing techniques on depth of cure of a composite resin. MATERIAL AND METHODS: Ten specimens of a composite resin were made in cylindrical cavities prepared in PVC plates (3.0 X 7.0 mm) for each light-curing technique. Four photoactivation methods were investigated: stepped, ramped, pulse-delay and traditional. Specimens were longitudinally sectioned and polished for microhardness measurements (kg/mm²), which were made at 0.1, 1.0, 2.0 and 4.0 mm from the irradiated surface. Data were subjected to ANOVA and Tukey's test. RESULTS: The effect of factors studied (curing method and distance from the surface) and the interaction of these factors was statistically significant (p
- Published
- 2009
- Full Text
- View/download PDF
5. Genetics and ontogeny are key factors influencing thermal resilience in a culturally and economically important bivalve.
- Author
-
Delorme NJ, King N, Cervantes-Loreto A, South PM, Baettig CG, Zamora LN, Knight BR, Ericson JA, Smith KF, and Ragg NLC
- Subjects
- Animals, HSP70 Heat-Shock Proteins genetics, HSP70 Heat-Shock Proteins metabolism, Thermotolerance genetics, Bivalvia genetics, Bivalvia physiology, New Zealand, Hot Temperature, Gills metabolism, Perna genetics, Perna physiology
- Abstract
Increasing seawater temperatures coupled with more intense and frequent heatwaves pose an increasing threat to marine species. In this study, the New Zealand green-lipped mussel, Perna canaliculus, was used to investigate the effect of genetics and ontogeny on thermal resilience. The culturally and economically significant mussel P. canaliculus (Gmelin, 1971) has been selectively-bred in New Zealand for two decades, making it a unique biological resource to investigate genetic interactions in a temperate bivalve species. Six selectively-bred full sibling families and four different ages, from early juveniles (6, 8, 10 weeks post-fertilisation) to sub-adults (52 weeks post-fertilisation), were used for experimentation. At each age, each family was exposed to a three-hour heat challenge, followed by recovery, and survival assessments. The shell lengths of live and dead juvenile mussels were also measured. Gill tissue samples from sub-adults were collected after the thermal challenge to quantify the 70 kDa heat shock protein gene (hsp70). Results showed that genetics, ontogeny and size influence thermal resilience in P. canaliculus, with LT
50 values ranging between 31.3 and 34.4 °C for all studied families and ages. Juveniles showed greater thermotolerance compared to sub-adults, while the largest individuals within each family/age class tended to be more heat sensitive than their siblings. Sub-adults differentially upregulated hsp70 in a pattern that correlated with net family survival following heat challenge, reinforcing the perceived role of inducible HSP70 protein in molluscs. This study provides insights into the complex interactions of age and genotype in determining heat tolerance of a key mussel species. As marine temperatures increase, equally complex selection pressure responses may therefore occur. Future research should focus on transcriptomic and genomic approaches for key species such as P. canaliculus to further understand and predict the effect of genetic variation and ontogeny on their survival in the context of climate change., (© 2024. The Author(s).)- Published
- 2024
- Full Text
- View/download PDF
6. Interactive effects of elevated temperature and Photobacterium swingsii infection on the survival and immune response of marine mussels (Perna canaliculus): A summer mortality scenario.
- Author
-
Azizan A, Venter L, Zhang J, Young T, Ericson JA, Delorme NJ, Ragg NLC, and Alfaro AC
- Subjects
- Animals, Temperature, Photobacterium, Immunity, Perna
- Abstract
The New Zealand Greenshell™ mussel (Perna canaliculus) is an economically important aquaculture species. Prolonged increases in seawater temperature above mussel thermotolerance ranges pose a significant threat to mussel survival and health, potentially increasing susceptibility to bacterial infections. Using challenge experiments, this study examined the combined effects of increased seawater temperature and bacterial (Photobacterium swingsii) infection on animal survival, haemocyte and biochemical responses of adult mussels. Mussels maintained at three temperatures (16, 20 and 24 °C) for seven days were either not injected (control), injected with sterile marine broth (injection control) or P. swingsii (challenged with medium and high doses) and monitored daily for five days. Haemolymph and tissue samples were collected at 24, 48, 72, 96, 120 h post-challenge and analysed to quantify bacterial colonies, haemocyte responses and biochemical responses. Mussels infected with P. swingsii exhibited mortalities at 20 and 24 °C, likely due to a compromised immune system, but no mortalities were observed when temperature was the only stressor. Bacterial colony counts in haemolymph decreased over time, suggesting bacterial clearance followed by the activation of immune signalling pathways. Total haemocyte counts and viability data supports haemocyte defence functions being stimulated in the presence of high pathogen loads at 24 °C. In the gill tissue, oxidative stress responses, measured as total antioxidant capacity and malondialdehyde (MDA) levels, were higher in infected mussels (compared to the controls) after 24h and 120h post-challenge at the lowest (16 °C) and highest temperatures (24 °C), indicating the presence of oxidative stress due to temperature and pathogen stressors. Overall, this work confirms that Photobacterium swingsii is pathogenic to P. canaliculus and indicates that mussels may be more vulnerable to bacterial pathogens under conditions of elevated temperature, such as those predicted under future climate change scenarios., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2024
- Full Text
- View/download PDF
7. Differential responses of selectively bred mussels ( Perna canaliculus ) to heat stress-survival, immunology, gene expression and microbiome diversity.
- Author
-
Ericson JA, Laroche O, Biessy L, Delorme NJ, Pochon X, Thomson-Laing J, Ragg NLC, and Smith KF
- Abstract
New Zealand's green-lipped mussel ( Perna canaliculus ) is an ecologically and economically important species. Marine heatwaves are increasing in frequency around NZ's coastline, and these events are correlated with increased stress and mortality of some aquaculture species. This study aimed to identify general biomarkers of heat stress in P. canaliculus and to assess whether responses differed between genetically distinct selectively bred mussels. We exposed three families of selectively bred mussels (families A, B and C) to three seawater temperature regimes in the laboratory: 1) a "control" treatment (ambient 12°C), 2) a 26°C heat challenge with a subsequent recovery period, and 3) a sustained 26°C heat challenge with no recovery. We investigated whether the survival, immune response (hemocyte concentration and viability, oxidative stress and total antioxidant capacity), hemocyte gene expression and gill microbiome differed between the families during the temperature challenges. In the sustained heat-stress treatment, family A had the highest survival rate (42% compared with 25% and 5% for families C and B, respectively). Gene expression levels significantly shifted during thermal stress and differed between families, with family A more dissimilar than families B and C. Family C had substantially more genes impacted by temperature treatment and timepoint than the other families, while family B had very little genes/pathways that responded to thermal stress. Genes related to heat shock proteins and immune responses (e.g., AIF1, CTSC, TOLL8, CASP9, FNTA, AHCY, CRYAB, PPIF) were upregulated in all families during heat stress. Microbiome species-richness differed between families before and during heat-stress, with family A having a distinctly different microbiome flora than the other families. Microbial diversity changed similarly in all families exposed to prolonged heat-stress, with species of Vibrio and Campylobacter increasing in these mussels. Our study highlights the use of non-lethal sampling of hemocytes as a diagnostic tool to explore the immune response and gene expression of selectively bred mussels, to predict their response to ocean warming. This approach can identify potential thermotolerant candidates for further selective breeding, which may increase the resilience of the mussel aquaculture industry in a warming ocean., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Ericson, Laroche, Biessy, Delorme, Pochon, Thomson-Laing, Ragg and Smith.)
- Published
- 2024
- Full Text
- View/download PDF
8. Histopathological changes in the greenshell mussel, Perna canaliculus, in response to chronic thermal stress.
- Author
-
Copedo JS, Webb SC, Ragg NLC, Ericson JA, Venter L, Schmidt AJ, Delorme NJ, and Alfaro AC
- Abstract
Climate change associated temperature challenges pose a serious threat to the marine environment. Elevations in average sea surface temperatures are occurring and increasing frequency of marine heatwaves resulting in mortalities of organisms are being reported. In recent years, marine farmers have reported summer mass mortality events of the New Zealand Greenshell mussel, Perna canaliculus, during the summer months; however, the etiological agents have yet to be determined. To elucidate the role of thermal stress, adult P. canaliculus were exposed to three chronic temperature treatments: a benign control of 17 °C and stressful elevations of 21 °C and 24 °C. Eight mussels per treatment were collected each month throughout a 14-month challenge period to identify and investigate histopathological differences among P. canaliculus populations exposed to the three temperatures. Histopathology revealed several significant deleterious alterations to tissues associated with temperature and exposure time. Increasing temperature and progression of time resulted in 1) an increase in the number of focal lipofuscin-ceroid aggregations, 2) an increase in focal hemocytosis, 3) an increase in the thickness of the sub-epithelial layer of the intestinal tract and 4) a decreased energy reserve cell (glycogen) coverage in the mantle. Prolonged exposure, irrespective of temperature, impacted gametogenesis, which was effectively arrested. Furthermore, increased levels of the heat shock protein 70 kDa (HSP 70) were seen in gill and gonad from thermally challenged mussels. The occurrence of the parasite Perkinsus olseni at month 5 in the 24 °C treatment, and month 7 at 21 °C was unexpected and may have exacerbated the fore-mentioned tissue conditions. Prolonged exposure to stable thermal conditions therefore appears to impact P. canaliculus, tissues with implications for broodstock captivity. Mussels experiencing elevated, temperatures of 21 and 24 °C demonstrated more rapid pathological signs. This research provides further insight into the complex host-pathogen-environment interactions for P. canaliculus in response to prolonged elevated temperature., Competing Interests: Declaration of competing interest There are no conflicts of interests associated to this work., (Copyright © 2023 Elsevier Ltd. All rights reserved.)
- Published
- 2023
- Full Text
- View/download PDF
9. The effect of simulated marine heatwaves on green-lipped mussels, Perna canaliculus: A near-natural experimental approach.
- Author
-
Venter L, Alfaro AC, Ragg NLC, Delorme NJ, and Ericson JA
- Abstract
Marine heatwaves (MHW) are projected for the foreseeable future, affecting aquaculture species, such as the New Zealand green-lipped mussel (Perna canaliculus). Thermal stress alters mussel physiology highlighting the adaptive capacity that allows survival in the face of heatwaves. Within this study, adult mussels were subjected to three different seawater temperature regimes: 1) low (sustained 18 °C), 2) medium MHW (18-24 °C, using a +1 °C per week ramp) and 3) high MHW (18-24 °C, using a +2 °C per week ramp). Sampling was performed over 11 weeks to establish the effects of temperature on P. canaliculus survival, condition, specific immune response parameters, and the haemolymph metabolome. A transient 25.5-26.5 °C exposure resulted in 61 % mortality, with surviving animals showing a metabolic adjustment within aerobic energy production, enabling the activation of molecular defence mechanisms. Utilisation of immune functions were seen within the cytology results where temperature stress affected the percentage of superoxide-positive haemocytes and haemocyte counts. From the metabolomics results an increase in antioxidant metabolites were seen in the high MHW survivors, possibly to counteract molecular damage. In the high MHW exposure group, mussels utilised anaerobic metabolism in conjunction with aerobic metabolism to produce energy, to uphold biological functions and survival. The effect of exposure time was mainly seen on very long-, and long chain fatty acids, with increases observed at weeks seven and eight. These changes were likely due to the membrane storage functions of fatty acids, with decreases at week eleven attributed to energy metabolism functions. This study supports the use of integrated analytical tools to investigate the response of marine organisms to heatwaves. Indeed, specific metabolic pathways and cellular markers are now highlighted for future investigations aimed at targeted measures. This research contributes to a larger program aimed to identify resilient mussel traits and support aquaculture management., Competing Interests: Declaration of competing interest All authors declare that they have no competing interests., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2023
- Full Text
- View/download PDF
10. Metabolite Changes of Perna canaliculus Following a Laboratory Marine Heatwave Exposure: Insights from Metabolomic Analyses.
- Author
-
Azizan A, Venter L, Jansen van Rensburg PJ, Ericson JA, Ragg NLC, and Alfaro AC
- Abstract
Temperature is considered to be a major abiotic factor influencing aquatic life. Marine heatwaves are emerging as threats to sustainable shellfish aquaculture, affecting the farming of New Zealand's green-lipped mussel [ Perna canaliculus (Gmelin, 1791)]. In this study, P. canaliculus were gradually exposed to high-temperature stress, mimicking a five-day marine heatwave event, to better understand the effects of heat stress on the metabolome of mussels. Following liquid chromatography-tandem mass spectrometry analyses of haemolymph samples, key sugar-based metabolites supported energy production via the glycolysis pathway and TCA cycle by 24 h and 48 h of heat stress. Anaerobic metabolism also fulfilled the role of energy production. Antioxidant molecules acted within thermally stressed mussels to mitigate oxidative stress. Purine metabolism supported tissue protection and energy replenishment. Pyrimidine metabolism supported the protection of nucleic acids and protein synthesis. Amino acids ensured balanced intracellular osmolality at 24 h and ammonia detoxification at 48 h. Altogether, this work provides evidence that P. canaliculus has the potential to adapt to heat stress up to 24 °C by regulating its energy metabolism, balancing nucleotide production, and implementing oxidative stress mechanisms over time. The data reported herein can also be used to evaluate the risks of heatwaves and improve mitigation strategies for aquaculture.
- Published
- 2023
- Full Text
- View/download PDF
11. Fatty acid profiles of more than 470 marine species from the Southern Hemisphere.
- Author
-
Nichols PD, Pethybridge HR, Zhang B, Virtue P, Meyer L, Dhurmeea Z, Marcus L, Ericson JA, Hellessey N, Every S, Wheatley K, Parrish CC, Eisenmann P, Baylis AMM, Bradshaw CJA, Bierwagen SL, Young JW, Couturier LIE, Rohner CA, Groß J, Waugh C, Phleger CF, Jackson C, Jackson G, Huveneers C, Bengtson Nash S, Brock M, and Mansour P
- Subjects
- Animals, Food Chain, Fishes, Zooplankton, Mammals, Fatty Acids analysis, Fatty Acids metabolism, Ecosystem
- Abstract
Lipid and fatty acid datasets are commonly used to assess the nutritional composition of organisms, trophic ecology, and ecosystem dynamics. Lipids and their fatty acid constituents are essential nutrients to all forms of life because they contribute to biological processes such as energy flow and metabolism. Assessment of total lipids in tissues of organisms provides information on energy allocation and life-history strategies and can be an indicator of nutritional condition. The analysis of an organism's fatty acids is a widely used technique for assessing nutrient and energy transfer, and dietary interactions in food webs. Although there have been many published regional studies that assessed lipid and fatty acid compositions, many only report the mean values of the most abundant fatty acids. There are limited individual records available for wider use in intercomparison or macro-scale studies. This dataset consists of 4856 records of individual and pooled samples of at least 470 different marine consumer species sampled from tropical, temperate, and polar regions around Australia and in the Southern, Indian, and Pacific Oceans from 1989 to 2018. This includes data for a diverse range of taxa (zooplankton, fish, cephalopods, chondrichthyans, and marine mammals), size ranges (0.02 cm to ~13 m), and that cover a broad range of trophic positions (2.0-4.6). When known, we provide a record of species name, date of sampling, sampling location, body size, relative (%) measurements of tissue-specific total lipid content and abundant fatty acids, and absolute content (mg 100 g
-1 tissue) of eicosapentaenoic acid (EPA, 20:5n3) and docosahexaenoic acid (DHA, 22:6n3) as important long-chain (≥C20 ) polyunsaturated omega-3 fatty acids. These records form a solid basis for comparative studies that will facilitate a broad understanding of the spatial and temporal distribution of marine lipids globally. The dataset also provides reference data for future dietary assessments of marine predators and model assessments of potential impacts of climate change on the availability of marine lipids and fatty acids. There are 480 data records within our data file for which the providers have requested that permission for reuse be granted, with the likely condition that they are included as a coauthor on the reporting of the dataset. Records with this condition are indicated by a "yes" under "Conditions_of_data_use" in Data S1: Marineconsumer_FAdata.csv (see Table 2 in Metadata S1 for more details). For all other data records marked as "No" under "Conditions_of_data_use," there are no copyright restrictions for research and/or teaching purposes. We request that users acknowledge use of the data in publications, research proposals, websites, and other outlets via formal citation of this work and original data sources as applicable., (© 2022 The Ecological Society of America.)- Published
- 2023
- Full Text
- View/download PDF
12. Pathogenicity and virulence of bacterial strains associated with summer mortality in marine mussels (Perna canaliculus).
- Author
-
Azizan A, Alfaro AC, Jaramillo D, Venter L, Young T, Frost E, Lee K, Van Nguyen T, Kitundu E, Archer SDJ, Ericson JA, Foxwell J, Quinn O, and Ragg NLC
- Subjects
- Animals, Seasons, Virulence Factors genetics, Virulence Factors metabolism, Seafood, Perna metabolism, Vibrio genetics
- Abstract
The occurrence of pathogenic bacteria has emerged as a plausible key component of summer mortalities in mussels. In the current research, four bacterial isolates retrieved from moribund Greenshell࣪ mussels, Perna canaliculus, from a previous summer mortality event, were tentatively identified as Vibrio and Photobacterium species using morpho-biochemical characterization and MALDI-TOF MS and confirmed as V. celticus, P. swingsii, P. rosenbergii, and P. proteolyticum using whole genome sequencing. These isolates were utilized in a laboratory challenge where mussels were injected with cell concentrations ranging from 105 to 109 CFU/mussel. Of the investigated isolates, P. swingsii induced the highest mortality. Additionally, results from quantitative polymerase chain reaction analysis, focusing on known virulence genes were detected in all isolates grown under laboratory conditions. Photobacterium rosenbergii and P. swingsii showed the highest expression levels of these virulence determinants. These results indicate that Photobacterium spp. could be a significant pathogen of P. canaliculus, with possible importance during summer mortality events. By implementing screening methods to detect and monitor Photobacterium concentrations in farmed mussel populations, a better understanding of the host-pathogen relationship can be obtained, aiding the development of a resilient industry in a changing environment., (© The Author(s) 2022. Published by Oxford University Press on behalf of FEMS.)
- Published
- 2022
- Full Text
- View/download PDF
13. Effects of seawater temperature and acute Vibriosp. challenge on the haemolymph immune and metabolic responses of adult mussels (Perna canaliculus).
- Author
-
Ericson JA, Venter L, Welford MRV, Kumanan K, Alfaro AC, and Ragg NLC
- Subjects
- Animals, Antioxidants metabolism, Biomarkers metabolism, Lysine pharmacology, Reactive Oxygen Species metabolism, Seawater, Temperature, Urea metabolism, gamma-Aminobutyric Acid pharmacology, Anti-Infective Agents pharmacology, Perna metabolism, Vibrio metabolism, Vibrio Infections
- Abstract
The New Zealand Greenshell™ mussel (Perna canaliculus) is an endemic bivalve species with cultural importance, that is harvested recreationally and commercially. However, production is currently hampered by increasing incidences of summer mortality in farmed and wild populations. While the causative factors for these mortality events are still unknown, it is believed that increasing seawater temperatures and pathogen loads are potentially at play. To improve our understanding of these processes, challenge experiments were conducted to investigate the combined effects of increased seawater temperature and Vibrio infection on the immune and metabolic responses of adult mussels. Biomarkers that measure the physiological response of mussels to multiple-stressors can be utilised to study resilience in a changing environment, and support efforts to strengthen biosecurity management. Mussels acclimated to two temperatures (16 °C and 24 °C) were injected with either autoclaved, filtered seawater (control) or Vibriosp. DO1 (infected). Then, haemolymph was sampled 24 h post-injection and analysed to quantify haemocyte immune responses (via flow-cytometry), antioxidant capacity (measured electrochemically) and metabolic responses (via gas chromatography-mass spectrometry) to bacterial infection. Both seawater temperature and injection type significantly influenced the immune and metabolite status of mussels. A lack of interaction effects between temperature and injection type indicated that the effects of Vibrio sp. 24 h post-infection were similar between seawater temperatures. Infected mussels had a higher proportion of dead haemocytes and lower overall haemocyte counts than uninfected controls. The proportion of haemocytes showing evidence of apoptosis was higher in mussels held at 24 °C compared with those held at 16 °C. The proportion of haemocytes producing reactive oxygen species did not differ between temperatures or injection treatments. Mussels held at 24 °C exhibited elevated levels of metabolites linked to the glycolysis pathway to support energy production. The saccharopin-lysine pathway metabolites were also increased in these mussels, indicating the role of lysine metabolism. A decrease in metabolic activity (decreases in BCAAs, GABA, urea cycle metabolites, oxidative stress metabolites) was largely seen in mussels injected with Vibrio sp. Itaconate increased as seen in previous studies, suggesting that antimicrobial activity may have been activated in infected mussels. This study highlights the complex nature of immune and metabolic responses in mussels exposed to multiple stressors and gives an insight into Vibrio sp. infection mechanisms at different seawater temperatures., (Copyright © 2022 Elsevier Ltd. All rights reserved.)
- Published
- 2022
- Full Text
- View/download PDF
14. Flow cytometric validation of a commercial kit to assess the concentration and viability of bivalve hemocytes.
- Author
-
Ericson JA, Ragg NLC, and Rolton A
- Subjects
- Animals, Cell Survival, Flow Cytometry, Hemocytes, Perna
- Published
- 2021
- Full Text
- View/download PDF
15. The Effects of Live Transport on Metabolism and Stress Responses of Abalone ( Haliotis iris ).
- Author
-
Alfaro AC, Nguyen TV, Venter L, Ericson JA, Sharma S, Ragg NLC, and Mundy C
- Abstract
The New Zealand abalone industry relies mostly on the export of processed products to distant Asian markets, notably China. Over the past five years, live export of high quality abalone from New Zealand has proven successful. However, transport of live animals is associated with multiple stressors that affect survival and meat quality at the end of the transport phase. Better understanding of transport-derived stress is needed to improve transport conditions and recovery at destination to ensure high product quality and safety throughout the supply chain. To this end, we applied an untargeted GC-MS-based metabolomics approach to examine the changes in metabolite profiles of abalone after a 2-day transport event and subsequent water re-immersion for 2 days. The results revealed alterations of many metabolites in the haemolymph and muscle of post-transported abalone. Decreased concentrations of many amino acids suggest high energy demands for metabolism and stress responses of transported abalone, while increases of other amino acids may indicate active osmoregulation and/or protein degradation due to oxidative stress and apoptosis. The accumulation of citric acid cycle intermediates and anaerobic end-products are suggestive of hypoxia stress and a shift from aerobic to anaerobic metabolism (resulting from aerial exposure). Interestingly, some features in the metabolite profile of reimmersed abalone resembled those of pre-transported individuals, suggesting progressive recovery after reimmersion in water. Evidence of recovery was observed in the reduction of some stress biomarkers (e.g., lactic acid, succinic acid) following reimmersion. This study revealed insights into the metabolic responses to transport stress in abalone and highlights the importance of reimmersion practices in the supply chain of live animal exports.
- Published
- 2021
- Full Text
- View/download PDF
16. Balancing essential and non-essential metal bioavailability during hatchery rearing of Greenshell mussel (Perna canaliculus) larvae.
- Author
-
French AD, Ragg NLC, Ericson JA, Goodwin E, McDougall DR, Mohammadi A, and Vignier J
- Abstract
The use of ethylenediaminetetraacetic acid (EDTA) during bivalve hatchery production is thought to improve larval yields due to the reduced exposure to toxic metals (such as Cu); however, few studies have focused on the bioavailability of metals during the rearing process. Greenshell™ mussels (Perna canaliculus) were reared for 48 h with and without EDTA (12 µM) exposure and larvae were subsequently raised to 21 days post-fertilisation with and without EDTA exposure. Survival, shell length, algal ingestion rate, swimming activity, total metal concentration in water, bioavailable metal concentrations and larval metal accumulation were monitored for the 21 day period. Larval fitness (specifically D-yields) was improved on day 2 in the EDTA treatment, whereas an overall negative effect of EDTA treatment on fitness was observed on day 10 and 21. During the first 48 h, increased survival in the EDTA treatment is believed to be due to the reduction of bioavailable Zn concentrations in the rearing seawater. No other metal (essential or non-essential) displayed a consistent trend when comparing metal bioavailability to any of the fitness parameters measured throughout the experiment. Though the measured metal bioavailability was not clearly linked to fitness, the uptake of Al, P, Cr, Fe, Co, Ni, Zn, As, Cd, and Hg by P. canaliculus was reduced during the first 48 h, suggesting that the biological regulation of these elements is just as important as the bioavailability. Overall, treatment of the rearing seawater with 12 µM EDTA is effective for improving Greenshell™ mussel larval yields by decreasing metal bioavailability during the first two days of development but has minimal benefit between day 2 and 21., (Copyright © 2021. Published by Elsevier Inc.)
- Published
- 2021
- Full Text
- View/download PDF
17. Antarctic Krill Lipid and Fatty acid Content Variability is Associated to Satellite Derived Chlorophyll a and Sea Surface Temperatures.
- Author
-
Hellessey N, Johnson R, Ericson JA, Nichols PD, Kawaguchi S, Nicol S, Hoem N, and Virtue P
- Subjects
- Animals, Antarctic Regions, Australia, Chlorophyll metabolism, Lipid Metabolism, Oceans and Seas, Satellite Communications, Seasons, Temperature, Triglycerides metabolism, Euphausiacea metabolism, Fatty Acids metabolism
- Abstract
Antarctic krill (Euphausia superba) are a key component of the Antarctic food web with considerable lipid reserves that are vital for their health and higher predator survival. Krill lipids are primarily derived from their diet of plankton, in particular diatoms and flagellates. Few attempts have been made to link the spatial and temporal variations in krill lipids to those in their food supply. Remotely-sensed environmental parameters provide large-scale information on the potential availability of krill food, although relating this to physiological and biochemical differences has only been performed on small scales and with limited samples. Our study utilised remotely-sensed data (chlorophyll a and sea surface temperature) coupled with krill lipid data obtained from 3 years of fishery-derived samples. We examined within and between year variation of trends in both the environment and krill biochemistry data. Chlorophyll a levels were positively related to krill lipid levels, particularly triacylglycerol. Plankton fatty acid biomarkers analysed in krill (such as n-3 polyunsaturated fatty acids) increased with decreasing sea surface temperature and increasing chlorophyll a levels. Our study demonstrates the utility of combining remote-sensing and biochemical data in examining biological and physiological relationships between Antarctic krill and the Southern Ocean environment.
- Published
- 2020
- Full Text
- View/download PDF
18. Near-future ocean acidification does not alter the lipid content and fatty acid composition of adult Antarctic krill.
- Author
-
Ericson JA, Hellessey N, Kawaguchi S, Nichols PD, Nicol S, Hoem N, and Virtue P
- Subjects
- Adaptation, Physiological, Animals, Carbon Dioxide analysis, Euphausiacea immunology, Phospholipids analysis, Principal Component Analysis, Sterols analysis, Acids chemistry, Euphausiacea metabolism, Fatty Acids analysis, Oceans and Seas
- Abstract
Euphausia superba (Antarctic krill) is a keystone species in the Southern Ocean, but little is known about how it will respond to climate change. Ocean acidification, caused by sequestration of carbon dioxide into ocean surface waters (pCO
2 ), alters the lipid biochemistry of some organisms. This can have cascading effects up the food chain. In a year-long laboratory experiment adult krill were exposed to ambient seawater pCO2 levels (400 μatm), elevated pCO2 levels mimicking near-future ocean acidification (1000, 1500 and 2000 μatm) and an extreme pCO2 level (4000 μatm). Total lipid mass (mg g-1 DM) of krill was unaffected by near-future pCO2 . Fatty acid composition (%) and fatty acid ratios associated with immune responses and cell membrane fluidity were also unaffected by near-future pCO2 , apart from an increase in 18:3n-3/18:2n-6 ratios in krill in 1500 μatm pCO2 in winter and spring. Extreme pCO2 had no effect on krill lipid biochemistry during summer. During winter and spring, krill in extreme pCO2 had elevated levels of 18:2n-6 (up to 1.2% increase), 20:4n-6 (up to 0.8% increase), lower 18:3n-3/18:2n-6 and 20:5n-3/20:4n-6 ratios, and showed evidence of increased membrane fluidity (up to three-fold increase in phospholipid/sterol ratios). These results indicate that the lipid biochemistry of adult krill is robust to near-future ocean acidification.- Published
- 2019
- Full Text
- View/download PDF
19. Adult Antarctic krill proves resilient in a simulated high CO 2 ocean.
- Author
-
Ericson JA, Hellessey N, Kawaguchi S, Nicol S, Nichols PD, Hoem N, and Virtue P
- Abstract
Antarctic krill ( Euphausia superba ) have a keystone role in the Southern Ocean, as the primary prey of Antarctic predators. Decreases in krill abundance could result in a major ecological regime shift, but there is limited information on how climate change may affect krill. Increasing anthropogenic carbon dioxide (CO
2 ) emissions are causing ocean acidification, as absorption of atmospheric CO2 in seawater alters ocean chemistry. Ocean acidification increases mortality and negatively affects physiological functioning in some marine invertebrates, and is predicted to occur most rapidly at high latitudes. Here we show that, in the laboratory, adult krill are able to survive, grow, store fat, mature, and maintain respiration rates when exposed to near-future ocean acidification (1000-2000 μatm p CO2 ) for one year. Despite differences in seawater p CO2 incubation conditions, adult krill are able to actively maintain the acid-base balance of their body fluids in near-future p CO2 , which enhances their resilience to ocean acidification., Competing Interests: The authors declare no competing interests.- Published
- 2018
- Full Text
- View/download PDF
20. Gene expression during the generation and activation of mouse neutrophils: implication of novel functional and regulatory pathways.
- Author
-
Ericson JA, Duffau P, Yasuda K, Ortiz-Lopez A, Rothamel K, Rifkin IR, and Monach PA
- Subjects
- Animals, Cytokines genetics, Mice, Transcriptional Activation, Up-Regulation, Cytokines metabolism, Gene Expression, Neutrophil Activation genetics, Neutrophils metabolism
- Abstract
As part of the Immunological Genome Project (ImmGen), gene expression was determined in unstimulated (circulating) mouse neutrophils and three populations of neutrophils activated in vivo, with comparison among these populations and to other leukocytes. Activation conditions included serum-transfer arthritis (mediated by immune complexes), thioglycollate-induced peritonitis, and uric acid-induced peritonitis. Neutrophils expressed fewer genes than any other leukocyte population studied in ImmGen, and down-regulation of genes related to translation was particularly striking. However, genes with expression relatively specific to neutrophils were also identified, particularly three genes of unknown function: Stfa2l1, Mrgpr2a and Mrgpr2b. Comparison of genes up-regulated in activated neutrophils led to several novel findings: increased expression of genes related to synthesis and use of glutathione and of genes related to uptake and metabolism of modified lipoproteins, particularly in neutrophils elicited by thioglycollate; increased expression of genes for transcription factors in the Nr4a family, only in neutrophils elicited by serum-transfer arthritis; and increased expression of genes important in synthesis of prostaglandins and response to leukotrienes, particularly in neutrophils elicited by uric acid. Up-regulation of genes related to apoptosis, response to microbial products, NFkB family members and their regulators, and MHC class II expression was also seen, in agreement with previous studies. A regulatory model developed from the ImmGen data was used to infer regulatory genes involved in the changes in gene expression during neutrophil activation. Among 64, mostly novel, regulatory genes predicted to influence these changes in gene expression, Irf5 was shown to be important for optimal secretion of IL-10, IP-10, MIP-1α, MIP-1β, and TNF-α by mouse neutrophils in vitro after stimulation through TLR9. This data-set and its analysis using the ImmGen regulatory model provide a basis for additional hypothesis-based research on the importance of changes in gene expression in neutrophils in different conditions.
- Published
- 2014
- Full Text
- View/download PDF
21. The art and science of weed mapping.
- Author
-
Barnett DT, Stohlgren TJ, Jarnevich CS, Chong GW, Ericson JA, Davern TR, and Simonson SE
- Subjects
- Geography, Time Factors, Environment, Maps as Topic, Plants classification
- Abstract
Land managers need cost-effective and informative tools for non-native plant species management. Many local, state, and federal agencies adopted mapping systems designed to collect comparable data for the early detection and monitoring of non-native species. We compared mapping information to statistically rigorous, plot-based methods to better understand the benefits and compatibility of the two techniques. Mapping non-native species locations provided a species list, associated species distributions, and infested area for subjectively selected survey sites. The value of this information may be compromised by crude estimates of cover and incomplete or biased estimations of species distributions. Incorporating plot-based assessments guided by a stratified-random sample design provided a less biased description of non-native species distributions and increased the comparability of data over time and across regions for the inventory, monitoring, and management of non-native and native plant species.
- Published
- 2007
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.