Faculty of Health and Environmental Sciences

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https://hdl.handle.net/10292/10759
The research carried out at AUT's Faculty of Health and Environmental Sciences can be broadly defined in three themes:
  • Health Sciences
  • School of Clinical Sciences
  • School of Public Health and Psychosocial Studies
  • School of Interprofessional Health Studies
  • Sciences
  • School of Science
  • Sport
  • School of Sport and Recreation

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Browsing Faculty of Health and Environmental Sciences by Subject "0601 Biochemistry and Cell Biology"

Now showing 1 - 7 of 7
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    Behavioural and Physiological Responses of Juvenile Geoduck (Panopea zelandica) Following Acute Thermal Stress
    (Elsevier, 2023-08-11) Sharma, Shaneel S; Venter, Leonie; Frost, Emily J; Alfaro, Andrea C; Ragg, Norman LC; Zamora, Leonardo N
    Climate extremes, such as heatwaves, are expected to become more intense and of longer duration in the near future. These climatic conditions may have a significant impact on the prospects of establishing a new aquaculture industry for the endemic New Zealand geoduck, Panopea zelandica. This study focused on characterising animal behaviour, haemocyte characteristics, and heat shock protein (HSP70 & HSP90) mRNA expression following exposure to elevated temperatures, such as those encountered during marine heatwaves around 20 °C and an extreme scenario of 25 °C, contrasted to an ambient temperature of 17 °C. After 24 h of heat challenge, P. zelandica were found to be significantly influenced by the thermal changes, as there were differences recorded in all the responses examined. With increasing temperatures, juvenile geoducks were observed to fully emerge from the sediment a behaviour that has not previously been quantified nor associated with stress in this species. The ability of P. zelandica juveniles to re-bury still warrants further investigation, as adults are unable to do so. Haemocyte analyses revealed an increase in the abundance of granulocytes, cellular aggregations, and size of these aggregations at the highest temperature exposure. Increased expression of the hsp70 gene in the haemolymph after exposure at 25 °C for 24 h was detected and attributed to attempts to mitigate protein denaturation caused by thermal stress. The inter-individual variability in the response of heat shock proteins recorded could aid in future selective breeding programs if it is reflected in net thermotolerance. P. zelandica shows great potential for growing in subtidal habitats around New Zealand, and this study highlights the importance of temperature considerations when selecting potential farm and reseeding locations.
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    Investigating the Effects of Chiropractic Care on Resting-State EEG of MCI Patients
    (Frontiers Media SA, 2024-06-11) Ziloochi, F; Niazi, IK; Amjad, I; Cade, A; Duehr, J; Ghani, U; Holt, K; Haavik, H; Shalchyan, V
    Introduction: Mild cognitive impairment (MCI) is a stage between health and dementia, with various symptoms including memory, language, and visuospatial impairment. Chiropractic, a manual therapy that seeks to improve the function of the body and spine, has been shown to affect sensorimotor processing, multimodal sensory processing, and mental processing tasks. Methods: In this paper, the effect of chiropractic intervention on Electroencephalogram (EEG) signals in patients with mild cognitive impairment was investigated. EEG signals from two groups of patients with mild cognitive impairment (n = 13 people in each group) were recorded pre- and post-control and chiropractic intervention. A comparison of relative power was done with the support vector machine (SVM) method and non-parametric cluster-based permutation test showing the two groups could be separately identified with high accuracy. Results: The highest accuracy was obtained in beta2 (25–35 Hz) and theta (4–8 Hz) bands. A comparison of different brain areas with the SVM method showed that the intervention had a greater effect on frontal areas. Also, interhemispheric coherence in all regions increased significantly after the intervention. The results of the Wilcoxon test showed that intrahemispheric coherence changes in frontal-occipital, frontal-temporal and right temporal-occipital regions were significantly different in two groups. Discussion: Comparison of the results obtained from chiropractic intervention and previous studies shows that chiropractic intervention can have a positive effect on MCI disease and using this method may slow down the progression of mild cognitive impairment to Alzheimer’s disease.
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    Metabolic Regulation of Copper Toxicity during Marine Mussel Embryogenesis
    (MDPI AG, 2023-07-11) Young, Tim; Gale, Samantha L; Ragg, Norman LC; Sander, Sylvia G; Burritt, David J; Benedict, Billy; Le, Dung V; Villas-Bôas, Silas G; Alfaro, Andrea C
    The development of new tools for assessing the health of cultured shellfish larvae is crucial for aquaculture industries to develop and refine hatchery methodologies. We established a large-volume ecotoxicology/health stressor trial, exposing mussel (Perna canaliculus) embryos to copper in the presence of ethylenediaminetetraacetic acid (EDTA). GC/MS-based metabolomics was applied to identify potential biomarkers for monitoring embryonic/larval health and to characterise mechanisms of metal toxicity. Cellular viability, developmental abnormalities, larval behaviour, mortality, and a targeted analysis of proteins involved in the regulation of reactive oxygen species were simultaneously evaluated to provide a complementary framework for interpretative purposes and authenticate the metabolomics data. Trace metal analysis and speciation modelling verified EDTA as an effective copper chelator. Toxicity thresholds for P. canaliculus were low, with 10% developmental abnormalities in D-stage larvae being recorded upon exposure to 1.10 μg·L-1 bioavailable copper for 66 h. Sublethal levels of bioavailable copper (0.04 and 1.10 μg·L-1) caused coordinated fluctuations in metabolite profiles, which were dependent on development stage, treatment level, and exposure duration. Larvae appeared to successfully employ various mechanisms involving the biosynthesis of antioxidants and a restructuring of energy-related metabolism to alleviate the toxic effects of copper on cells and developing tissues. These results suggest that regulation of trace metal-induced toxicity is tightly linked with metabolism during the early ontogenic development of marine mussels. Lethal-level bioavailable copper (50.3 μg·L-1) caused severe metabolic dysregulation after 3 h of exposure, which worsened with time, substantially delayed embryonic development, induced critical oxidative damage, initiated the apoptotic pathway, and resulted in cell/organism death shortly after 18 h of exposure. Metabolite profiling is a useful approach to (1) assess the health status of marine invertebrate embryos and larvae, (2) detect early warning biomarkers for trace metal contamination, and (3) identify novel regulatory mechanisms of copper-induced toxicity.
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    Metabolite Changes of Perna canaliculus Following a Laboratory Marine Heatwave Exposure: Insights from Metabolomic Analyses
    (MDPI AG, 2023-07-03) Azizan, Awanis; Venter, Leonie; Jansen van Rensburg, Peet J; Ericson, Jessica A; Ragg, Norman LC; Alfaro, Andrea C
    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.
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    Reliability of Ankle Dorsiflexor Muscle Strength, Rate of Force Development, and Tibialis Anterior Electromyography After Stroke
    (F1000 Research Ltd, 2023-04-20) Olsen, Sharon; Taylor, Denise; Niazi, Imran Khan; Mawston, Grant; Rashid, Usman; Alder, Gemma; Stavric, Verna; Nedergaard, Rasmus Bach; Signal, Nada
    Background Measures of hemiparetic ankle dorsiflexor muscle strength and rate of force development (RFD) are often used to determine the efficacy of rehabilitation interventions after stroke. However, evidence supporting the reliability of these measures is limited. This brief report provides a secondary analysis investigating the between-session reliability of isometric ankle dorsiflexor muscle strength, rate of force development (RFD), and tibialis anterior electromyography (TA EMG), in people with chronic stroke. Method Participants (n=15) completed three maximal isometric contractions of the ankle dorsiflexor muscles as fast as possible using a rigid dynamometer. Tests were repeated seven days later. Outcomes included ankle dorsiflexor isometric maximal voluntary contraction (MVC), RFD in the first 200ms (RFD200ms), time to reach 90% MVC, and peak TA EMG. Data were analysed for 13 participants using intra-class correlation coefficients (ICC) and standard error of the measure percentage (SEM%). Results Reliability was higher when analysing the mean of three trials rather than the best of three trials. There was excellent reliability for isometric dorsiflexor MVC (ICC 0.97 [95% CI 0.92, 0.99], SEM% 7%). However, for other outcomes, while the ICC indicated good reliability, the lower bound of the 95% confidence interval of the ICC fell in the moderate range for TA EMG (ICC 0.86 [95% CI 0.60, 0.96], SEM% 25%) and time to reach 90% MVC (ICC 0.8 [95% CI 0.53, 0.93], SEM% 23%) and in the poor range for dorsiflexor RFD200ms (ICC 0.79 [95% CI 0.48, 0.92], SEM% 24%). Conclusion The findings raise concerns about the reliability of measures of rapid force production in the dorsiflexor muscles after stroke. Given the functional significance of the ankle dorsiflexors, larger studies should be conducted to further investigate these concerns and explore reliable methods for measuring rapid force production in the hemiparetic dorsiflexor muscles.
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    Reliability of Ankle Dorsiflexor Muscle Strength, Rate of Force Development, and Tibialis Anterior Electromyography After Stroke
    (F1000 Research Ltd, 2023-04-20) Olsen, Sharon; Taylor, Denise; Niazi, Imran Khan; Mawston, Grant; Rashid, Usman; Alder, Gemma; Stavric, Verna; Nedergaard, Rasmus Bach; Signal, Nada
    Background: Measures of hemiparetic ankle dorsiflexor muscle strength and rate of force development (RFD) are often used to determine the efficacy of rehabilitation interventions after stroke. However, evidence supporting the reliability of these measures is limited. This brief report provides a secondary analysis investigating the between-session reliability of isometric ankle dorsiflexor muscle strength, rate of force development (RFD), and tibialis anterior electromyography (TA EMG), in people with chronic stroke. Method: Participants (n=15) completed three maximal isometric contractions of the ankle dorsiflexor muscles as fast as possible using a rigid dynamometer. Tests were repeated seven days later. Outcomes included ankle dorsiflexor isometric maximal voluntary contraction (MVC), RFD in the first 200ms (RFD200ms), time to reach 90% MVC, and peak TA EMG. Data were analysed for 13 participants using intra-class correlation coefficients (ICC) and standard error of the measure (SEM). Results: When the mean of three trials was analysed, there was excellent reliability for isometric dorsiflexor MVC (ICC 0.97 [95% CI 0.92-0.99]), moderate reliability for TA EMG (ICC 0.86 [0.60-0.96]) and time to reach 90% MVC (ICC 0.8 [0.53-0.93]) and poor reliability for dorsiflexor RFD200ms (ICC 0.79 [0.48-0.92]). Conclusion: Given the functional significance of the ankle dorsiflexors, future research should investigate more reliable methods for measuring rapid force production in the dorsiflexor muscles after stroke.
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    Time Course of Recovery Across Various Compound Resistance Exercises and the Relationship Between Cell-Free DNA and Performance
    (Wiley, 2019-04-01) Johnson, Trevor K; Belcher, Daniel J; Sousa, Colby A; Carzoli, Joseph P; Visavadiya, Nishant P; Helms, Eric R; Zoeller, Robert F; Whitehurst, Michael; Zourdos, Michael Christopher
    *This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal. In practice, the deadlift is perceived to require a longer recovery time than the squat or bench press. However, the time course of recovery has not yet between compared between these three exercises. Further, recent data have indicated an inverse relationship between cell-free DNA (cfDNA) and exercise performance, however, these relationships are preliminary. PURPOSE The purpose of this investigation was to examine the magnitude of muscle damage and subsequent recovery time between the squat, bench press, and deadlift. METHODS Twelve males (age: 24.5±3.8yrs, body mass: 84.01±15.44kg, height: 173.43±8.57cm, training age: 7.1±4.2yrs) performed 4 sets to failure at 80% of a one-repetition maximum (1RM) on the squat, bench press, and deadlift in successive weeks; in a counterbalanced order. Measures of indirect muscle damage and performance fatigue were assessed immediately prior to, post-exercise, and 24, 48, 72, and 96hrs post-exercise. Outcome measures were delayed onset muscle soreness (DOMS), average concentric velocity (ACV) at 70% of 1RM, creatine kinase (CK), lactate dehydrogenase (LDH), and cfDNA. RESULTS There were no between condition differences for changes in CK, LDH, or DOMS (p>0.05). However, ACV decreased in the squat condition for up to 72 hours (p=0.02, −8.61%) and in the bench press (p<0.01, −26.69%) immediately post-exercise, but did not decrease in the deadlift condition (p>0.05). There was a main time effect for increased cfDNA in the squat (p<0.01) and bench press (p<0.05), but not the deadlift (p=0.153). Further, there were various significant (p<0.05) and positive relationships between cfDNA and ACV during the recovery period. Specifically, immediately post-exercise changes in cfDNA were positively related changes in post-exercise ACV the squat (r=0.64, p=0.02). Further, immediately post-exercise changes in cfDNA were significantly related to deadlift ACV or approached a significant relationship with deadlift ACV at every recovery time point (immediate: r=0.52, p=0.09; 24hrs: r=0.66, p=0.02; 48hrs: r=0.73, p=0.01; 72hrs: r=0.64, p=0.03; 96hrs: r=0.66, p=0.02). CONCLUSION These results suggest that the deadlift does not require a longer recovery period than the squat or bench press following high volume training to failure in well-trained men. Further, changes in post-exercise cfDNA may predict velocity of resistance exercise performance throughout a 96-hour recovery period. Importantly, we observed direct relationships between cfDNA and performance, while a previous investigation has reported inverse relationships in this respect. Of note, our immediately post blood collection occurred ~10 minutes post-exercise, thus it is possible there was an increase in DNase activity, resulting in a decrease in serum cfDNA during the 10-minute window between the end of exercise and blood collection. Further, DNase kinetics have considerable individual variation and may account for some disparities.
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