ORCID Profile
0009-0002-5496-0106
Current Organisation
The University of Newcastle
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Publisher: Public Library of Science (PLoS)
Date: 21-07-2016
Publisher: Springer Science and Business Media LLC
Date: 19-09-2018
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/MF18487
Abstract: Estuarine waters are heavily influenced by catchment land use and run-off, and acid sulfate soils directly affect both dissolved oxygen (DO) and aluminium concentrations. This can affect harvested species (including benthic crustaceans) and can have concomitant effects on their productivity. In this study we evaluated the effects of hypoxia (DO concentrations & mgL–1) on eastern school prawn (Metapenaeus macleayi) under enhanced and ambient aluminium concentrations (mean±s.d., 0.112±0.009 and 0.015±0.002mgL–1 respectively). There was a significant increase in survival with increasing DO and LC50 was ~0.9mgL–1, although survival decreased at higher DO concentrations in the presence of enhanced aluminium concentrations. Total fatty acid and amino acid concentrations were significantly greater in prawns subjected to hypoxia, regardless of aluminium exposure. Docosahexaenoic acid, stearic acid, palmitic acid and behenic acid (fatty acids) and leucine, isoleucine, phenylalanine and asparagine (amino acids) contributed to differences in fatty and amino acid profiles among treatments. Hypoxia and aluminium concentrations in nursery habitats of south-eastern Australian estuaries can exceed the conditions evaluated, and could thus affect survival of M. macleayi. More generally, these results have implications for other crustacean species in estuaries that drain coastal flood plains, and the fisheries that rely on them.
Publisher: Elsevier BV
Date: 11-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9EM00394K
Abstract: Substantial differences in PFAA profiles were associated with significant differences in fatty acid and amino acid profiles.
Publisher: Public Library of Science (PLoS)
Date: 09-12-2016
Publisher: Springer Science and Business Media LLC
Date: 08-08-2013
Publisher: Elsevier BV
Date: 05-2018
DOI: 10.1016/J.JCHROMB.2018.03.018
Abstract: The composition and integrity of the bacterial cytoplasmic membrane is critical to the survival of staphylococci in dynamic environments and it is important to investigate how the cell membrane responds to changes in the environmental conditions. The staphylococcal membrane differs from eukaryotic and many other bacterial cell membranes by having a high abundance of branch fatty acids and relatively few unsaturated fatty acids. The range of available methods for extraction and efficient analyses of staphylococcal fatty acids was initially appraised to identify the best potential procedures for appraisal. Staphylococcus aureus subsp. aureus Rosenbach (ATCC® 29213) was grown under optimal conditions to generate a cell biomass to compare the efficiencies of three approaches to extract and prepare methyl esters of the membrane fatty acids: (1) acidic direct transesterification of lipids, (2) modified basic direct transesterification of membrane lipids with adjusted reaction times and temperatures, and (3) base catalysed hydrolysis followed by acid catalysed esterification in two separate chemical reactions (MIDI process). All methods were able to extract fatty acids from the cell mass effectively where these lipids represented approximately 5% of the cellular dry mass. The acidic transesterification method had the least number of steps, the lowest coefficient of variation at 6.7% and good resistance to tolerating water. Basic transesterification was the least accurate method showing the highest coefficient of variation (26%). The MIDI method showed good recoveries, but had twice the number of steps and a coefficient of variation of 16%. It was also found that there was no need to use an anti-oxidant such as BHT for the protection of polyunsaturated fatty acids when the GC-MS injection liner was clean. It was concluded that the acidic transesterification procedures formed the most efficient and reproducible method for the analyses of staphylococcal membrane fatty acids.
Publisher: Springer Science and Business Media LLC
Date: 18-08-2020
Publisher: Brill
Date: 07-12-2015
DOI: 10.3920/CEP150027
Abstract: Little is known about the amino acid composition of horse sweat, but significant fluid losses can occur during exercise with the potential to facilitate substantial nutrient losses. Sweat and plasma amino acid compositions for Standardbred horses were assessed to determine losses during a standardised training regime. Two cohorts of horses 2013 (n=5) and 2014 (n=6) were assessed to determine baseline levels of plasma and sweat amino acids. An amino acid supplement designed to counter losses in sweat during exercise was provided after morning exercise daily for 5 weeks (2013, n=5 2014, n=4). After the supplementation period, blood and sweat s les were collected to assess amino acid composition changes. From baseline assessments of sweat in both cohorts, it was found that serine, glutamic acid, histidine and phenylalanine were present at up to 9 times the corresponding plasma concentrations and aspartic acid at 0-2.2 μmol/l in plasma was measured at 154-262 μmol/l in sweat. In contrast, glutamine, asparagine, methionine and cystine were conserved in the plasma by having lower concentrations in the sweat. The predominant plasma amino acids were glycine, glutamine, alanine, valine, serine, lysine and leucine. As the sweat amino acid profile did not simply reflect plasma composition, it was proposed that mechanisms exist to generate high concentrations of certain amino acids in sweat whilst selectively preventing the loss of others. The estimated amino acid load in 16 l of circulating plasma was 3.8-4.3 g and the calculated loss via sweat during high intensity exercise was 1.6-3.0 g. Following supplementation, total plasma amino acid levels from both cohorts increased from initial levels of 2,293 and 2,044 µmol/l to post-supplementation levels of 2,674 and 2,663 µmol/l respectively (P .05). It was concluded that the strategy of providing free amino acids immediately after exercise resulted in raising resting plasma amino acid levels.
Publisher: Public Library of Science (PLoS)
Date: 08-04-2014
No related grants have been discovered for Marcus Crompton.