ORCID Profile
0000-0002-2913-9335
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Publisher: CSIRO Publishing
Date: 2019
DOI: 10.1071/AN17141
Abstract: Ruminant livestock contribute to atmospheric methane (CH4) from enteric microbial fermentation of feed in the reticulo-rumen. Our research aimed to increase understanding of how digestive characteristics and rumen anatomy of the host animal contribute to variation in CH4 emissions between in idual sheep. In total, 64 ewes were used in an incomplete block experiment with four experimental test periods (blocks). Ewes were chosen to represent the ersity of phenotypic variation in CH4 emissions: there were at least 10 offspring from each of four sires and a range of liveweights. Throughout the experiment, the ewes were fed equal parts of lucerne and oaten chaff, twice daily, at 1.5 times the maintenance requirements. Daily CH4 emission (g/day) increased significantly (P & 0.001) with an increasing dry-matter intake (DMI) and reticulo-rumen volume (P & 0.001). Lower methane yield (g CH4/kg DMI) was associated with shorter mean retention times of liquid (r = 0.59 P & 0.05) and particle (r = 0.63 P & 0.05) phases of the digesta in the rumen. Significant between sire variation was observed in CH4 emissions and in rumen volume (P = 0.02), the masses of liquids (P = 0.009) and particles (P & 0.03) in the rumen and the proportion of gas in the dorsal sac of the rumen (P = 0.008). The best predictors of variation in CH4 emissions due to the host were DMI, CO2 emissions, rumen volume, liveweight, mean retention time of particles in the rumen, dorsal papillae density and the proportion of liquid in the contents of the rumen compartments.
Publisher: CSIRO Publishing
Date: 2023
DOI: 10.1071/AN22425
Publisher: Elsevier BV
Date: 06-2012
DOI: 10.1016/J.JPROT.2011.12.013
Abstract: The research was aimed at finding which membrane proteins of the rumen bacterium Butyrivibrio proteoclasticus are involved in the uptake of carbohydrates resulting from extracellular enzymatic degradation of hemicellulose and fructan. The proteomic analysis of cells grown with fructose or xylan as the sole substrate identified 13 membrane proteins predicted to function as carbohydrate transporters. One protein detected was the membrane component of a fructose-specific phosphoenolpyruvate:sugar phosphotransferase system believed to be involved in the fructose uptake following extracellular fructan breakdown. The other 12 proteins were all ABC transport system substrate-binding proteins, nine of which belong to functional category COG1653 that includes proteins predicted to transport oligosaccharides. Four of the SBPs were significantly upregulated in xylan grown cells, and three of these were found in polysaccharide utilisation loci where they are clustered with other genes involved in hemicellulose breakdown and metabolism. It is possible that the carbon source available regulates a wider network of genes. The information on the mechanisms used by rumen bacteria to take up carbohydrates from their environment may improve our understanding of the ruminant digestion and facilitate strategies for improved pasture and stored feed utilisation.
Publisher: American Chemical Society (ACS)
Date: 29-11-2012
DOI: 10.1021/PR200864J
Abstract: Plant polysaccharide-degrading rumen microbes are fundamental to the health and productivity of ruminant animals. Butyrivibrio proteoclasticus B316(T) is a gram-positive, butyrate-producing anaerobic bacterium with a key role in hemicellulose degradation in the rumen. Gel-based proteomics was used to examine the growth-phase-dependent abundance patterns of secreted proteins recovered from cells grown in vitro with xylan or xylose provided as the sole supplementary carbon source. Five polysaccharidases and two carbohydrate-binding proteins (CBPs) were among 30 identified secreted proteins. The endo-1,4-β-xylanase Xyn10B was 17.5-fold more abundant in the culture medium of xylan-grown cells, which suggests it plays an important role in hemicellulose degradation. The secretion of three nonxylanolytic enzymes and two CBPs implies they augment hemicellulose degradation by hydrolysis or disruption of associated structural polysaccharides. Sixteen ATP-binding cassette (ABC) transporter substrate-binding proteins were identified, several of which had altered relative abundance levels between growth conditions, which suggests they are important for oligosaccharide uptake. This study demonstrates that B. proteoclasticus modulates the secretion of hemicellulose-degrading enzymes and ATP-dependent sugar uptake systems in response to growth substrate and supports the notion that this organism makes an important contribution to polysaccharide degradation in the rumen.
Publisher: CSIRO Publishing
Date: 2019
DOI: 10.1071/AN17447
Abstract: Livestock produce 10% of the total CO2-equivalent greenhouse gases in Australia, predominantly as methane from rumen fermentation. Genetic selection has the potential to reduce emissions and be adopted in Australian grazing systems. Developing a breeding objective for reduced methane emissions requires information about heritability, genetic relationships, when best to measure the trait and knowledge of the annual production of methane. Among- and within-animal variation in methane production, methane yield and associated traits were investigated, so as to determine the optimal time of measurement and the relationship between that measurement and the total production of methane. The present study measured 96 ewes for methane production, liveweight, feed intake, rumen volume and components, and volatile fatty acid (VFA) production and composition. Measurements were recorded at three ages and different physiological states, including growing (12 months), dry and pregnant (21 months) and dry (non-pregnant, non-lactating 28 months of age). The single biggest determinant of methane production was feed intake, but there were additional effects of age, proportion of propionate to (acetate+butyrate) in rumen VFA, total VFA concentration and CO2 flux. Rumen volume and pregnancy status also significantly affected methane production. Methane production, CO2 flux, liveweight, feed intake and rumen volume had high repeatability (& %), but repeatability of methane yield and VFA traits were low (& %). There were no interactions between sire and age (or pregnancy status) for methane traits. This suggests that methane could be measured at any time in the production cycle. However, because MY is reduced during pregnancy, it might be best to measure methane traits in dry ewes (neither pregnant nor lactating).
Publisher: MDPI AG
Date: 27-10-2015
Publisher: Elsevier BV
Date: 09-2014
DOI: 10.1016/J.JPROT.2014.07.017
Abstract: The mechanisms underlying resistance to challenge by gastrointestinal nematode parasites in sheep are complex. Using DIGE, we profiled ovine lymph proteins in lambs with host resistance (R), resilience (Ri) or susceptibility (S) to a daily trickle challenge with the nematode Trichostrongylus colubriformis. Efferent intestinal lymph was collected prior to infection (day 1) and on days 5 and 10 post-infection. Eight proteins identified by LC-MS/MS, showed differences relating to host genotype. Of these, Serpin A3-3 and Serpin A3-7 have not been reported previously in the lymph proteome. Three acute phase proteins showed significant differences relating to interactions between breeding line and parasite challenge, including complement C3β, C3α and haptoglobin (Hp) β. In the R lambs C3α was significantly up regulated (P<0.05) on day 10, while in the Ri lambs Hp β was significantly down regulated (P<0.05). In the S lambs, levels of C3β were up regulated and levels of Hp β down regulated (both P<0.05) on day 10. Hence we demonstrate that acute phase inflammation proteins contribute to differences in the innate immune response of sheep to challenge by T. colubriformis. The findings may lead to the development of new approaches to combat nematode infestations in sheep production systems. Breeding lines of sheep with resistance (R), resilience (Ri) or susceptibility (S) to nematode infections provide an experimental model to examine the biological mechanisms underlying the ability of some sheep to expel worms and remain healthy without the use of an anthelmintic. Using proteomics we identified differences in the expression of acute phase lymph proteins in the R, Ri and S lambs. The results will assist the development of alternative control strategies to manage nematode infections in livestock.
Publisher: Elsevier BV
Date: 04-2003
DOI: 10.1016/S0006-291X(03)00549-7
Abstract: Previously we found elevated beacon gene expression in the hypothalamus of obese Psammomys obesus. Beacon administration into the lateral ventricle of P. obesus stimulated food intake and body weight gain. In the current study we used yeast two-hybrid technology to screen for proteins in the human brain that interact with beacon. CLK4, an isoform of cdc2/cdc28-like kinase family of proteins, was identified as a strong interacting partner for beacon. Using active recombinant proteins and a surface plasmon resonance based detection technique, we demonstrated that the three members of this subfamily of kinases (CLK1, 2, and 4) all interact with beacon. Based on the known sequence and functional properties of beacon and CLKs, we speculate that beacon could either modulate the function of key regulatory molecules such as PTP1B or control the expression patterns of specific genes involved in the central regulation of energy metabolism.
Publisher: Public Library of Science (PLoS)
Date: 18-10-2022
DOI: 10.1371/JOURNAL.PONE.0273184
Abstract: Ruminant livestock are a major contributor to Australian agricultural sector carbon emissions. Variation in methane (CH 4 ) produced from enteric microbial fermentation of feed in the reticulo-rumen of sheep differs with different digestive functions. We isolated rumen epithelium enzymatically to extract membrane and cytosol proteins from sheep with high (H) and low (L) CH 4 emission. Protein abundance was quantified using SWATH-mass spectrometry. The research found differences related to the metabolism of glucose, lactate and processes of cell defence against microbes in sheep from each phenotype. Enzymes in the methylglyoxal pathway, a side path of glycolysis, resulting in D-lactate production, differed in abundance. In the H CH 4 rumen epithelium the enzyme hydroxyacylglutathione hydrolase (HAGH) was 2.56 fold higher in abundance, whereas in the L CH 4 epithelium lactate dehydrogenase D (LDHD) was 1.93 fold higher. Malic enzyme 1 which converts D-lactate to pyruvate via the tricarboxylic cycle was 1.57 fold higher in the L CH 4 phenotype. Other proteins that are known to regulate cell defence against microbes had differential abundance in the epithelium of each phenotype. Differences in the abundance of enzymes involved in the metabolism of glucose were associated with H and L CH 4 phenotype sheep. Potentially this represents an opportunity to use protein markers in the rumen epithelium to select low CH 4 emitting sheep.
Publisher: Elsevier BV
Date: 02-1999
Publisher: Elsevier BV
Date: 03-2007
DOI: 10.1016/J.MEATSCI.2006.08.005
Abstract: Exercise has been shown previously to reduce the water holding capacity (WHC) of meat in lamb. The consequence of changes in the distribution of ions pre- and post-rigor and proteolysis on WHC is relatively unknown. Twelve crossbred lambs were used to investigate the effect of exercise on the meat quality traits of the Longissimus thoracis et lumborum (LTL) muscle. There were no treatment effects on Warner-Bratzler shear force (WBSF), myofibril and sarcoplasmic protein solubility, denaturation or sarcomere length. With exercise the initial pH of the muscle was lower and the rate of pH fall to rigor was faster compared to controls. Exercise caused increased purge and meat fluid had a lower osmolarity, magnesium, potassium and sodium concentration. Proteolysis of desmin occurred after day 3 and vinculin on day 7 of ageing with exercise. It was concluded that exercise caused changes in the distribution of ions and the proteolysis of muscle proteins that reduced the ability of the muscle to bind or hold water.
Publisher: Bioscientifica
Date: 05-2000
Abstract: Many tumours secrete IGF-II in incompletely processed precursor forms. The ability of these pro-IGF-II forms to complex with the six IGF binding proteins (IGFBPs) is poorly understood. In this study, pro-IGF-II has been extracted from the serum and tumour tissue of two patients with non-islet cell tumour hypoglycaemia. These s les were used to study binary complex formation with IGFBPs-1 to -6 using competitive IGF-II binding assays and ternary complex formation with IGFBP-3 and IGFBP-5. In each case, IGFBPs-1 to -6 showed little difference in their ability to form binary complexes with recombinant IGF-II or tumour-derived pro-IGF-II forms, when the preparations were standardised according to IGF-II immunoreactivity. As previously described, ternary complex formation by acid-labile subunit (ALS) with IGFBP-3 and pro-IGF-II was greatly decreased compared with complex formation with mature IGF-II. In contrast, ALS bound similarly to IGFBP-5 in the presence of pro-IGF-II and mature IGF-II. These studies suggest that pro-IGF-II preferentially forms binary complexes with IGFBPs, and ternary complexes with IGFBP-5, rather than ternary complexes with IGFBP-3 as seen predominantly in normal serum. This may increase the tissue availability of serum pro-IGF-II, allowing its insulin-like potential to be realised.
Publisher: S. Karger AG
Date: 1999
DOI: 10.1159/000014603
Publisher: Springer Science and Business Media LLC
Date: 06-1996
DOI: 10.1007/BF02507106
Abstract: In the pediatric population, severe Clostridioides difficile infection (CDI) sometimes occurs, but most cases are asymptomatic. The asymptomatic carriage rate in pediatric populations is reportedly higher than in the adult population. It is difficult to diagnose CDI, even if C. difficile is detected in children with diarrhea. This study aimed to evaluate the positivity rate of toxigenic C. difficile in the pediatric population with diarrhea. We collected and retrospectively analyzed gastrointestinal pathogen multiplex PCR results of 960 patients to estimate the positivity rate of toxigenic C. difficile in pediatric populations aged between 0 and 18 years. The overall rate of C. difficile toxin B positivity was 10.1% in the stool s les. The positivity rate peaked in 1-year-old infants (29/153, 19.0%) and continually decreased thereafter. The positivity rate we observed was lower than the rates described in the literature. Remarkably, no C. difficile was detected in neonates. Antibiotic usage was inversely related to the positivity rate, especially in infants < 2 years of age. The odds ratio of antibiotics was 0.44 (95% confidence interval (CI) 0.28-0.68 P < 0.001). The presence of concomitant gastrointestinal pathogens was not associated with toxigenic C. difficile positivity. Even though toxigenic C. difficile infection is neither an important nor a common cause of pediatric diarrhea, children can spread it to adults at risk of developing CDI. The pediatric population can act as hidden reservoirs for pathogenic strains in the community.
Publisher: MDPI AG
Date: 20-09-2023
Publisher: Wiley
Date: 08-2003
DOI: 10.1034/J.1600-0625.2003.00068.X
Abstract: Parathyroid hormone-related protein (PTHrP) is secreted by skin epithelial cells and is thought to play an important role in the development and function of the hair follicle. It was hypothesized that PTHrP binds to receptors in dermal papilla cells and modulates intracellular signaling systems in these cells. We tested the effects of PTHrP on protein synthesis, protein kinase A (PKA) and protein kinase C (PKC) activities as well as tyrosine phosphorylation in rat vibrissa dermal papilla and capsular fibroblast cells. Cells were cultured in the presence or absence of the N-terminal peptide PTHrP1-34 for 48 h and detergent extracts prepared. Proteins were separated by electrophoresis. Phosphotyrosine and the PTH/PTHrP receptor immunoreactivity was identified by Western blot analysis. PKC and PKA activities in the cells were measured using colorimetric enzyme assays. Extracts of both dermal papilla cells and capsular fibroblasts displayed immunoreactivity to the PTH/PTHrP receptor. Electrophoresis showed that PTHrP treatment reduced the density of a 50-kDa protein in dermal papilla cells but not in capsular fibroblasts. Media conditioned by the cells showed similar changes, indicating that the PTHrP-modulated 50-kDa protein was secreted. Furthermore, 2-D gel electrophoresis indicated that the protein had a number of phosphorylation sites. Western analysis with antiphosphotyrosine antibodies confirmed a significant decrease in the intensity of a phosphorylated 50-kDa protein in papilla cells and papilla cell-conditioned medium. PKC and PKA activities of papilla cells were unaffected by PTHrP. However, activities of PKC were increased and PKA reduced in capsular fibroblasts following peptide treatment. These cell-specific effects showed that endogenous PTHrP may activate different intracellular pathways in mesenchymal cells of skin and elicit changes in levels of locally secreted proteins that specifically modulate normal follicular function.
Publisher: Bioscientifica
Date: 04-2001
Abstract: Insulin-like growth factor-binding protein-3 (IGFBP-3) is a member of a family of structurally conserved proteins (IGFBP-1 to -6) which act as carriers and regulators of the mitogenic peptide hormones IGF-I and IGF-II. Members of the IGFBP family share conserved cysteine-rich amino- and carboxyl-terminal regions. The amino-terminal domain of these proteins is recognised to contain an IGF-binding determinant, but evidence to support a binding site in the carboxyl-terminal region of the protein is less rigorous. To further investigate this, we have synthesised both the amino-terminal (residues 1-88 N-88) and carboxyl-terminal (residues 165-264 C-165) domains of human IGFBP-3 in bacteria, as fusion proteins with a carboxyl-terminal FLAG peptide. Although only C-165 showed binding to IGF-I and -II by solution-binding assays, both N-88 and C-165 demonstrated binding to IGF-I and -II by biosensor analysis albeit with reduced affinities compared with full-length IGFBP-3. Only the carboxyl-terminal fragment (C-165) was able to form hetero-trimeric complexes with IGF-I and the acid-labile subunit (ALS). We conclude that the carboxyl-terminal domain of IGFBP-3 contains an IGF-binding determinant and can form ternary complexes with ALS.
Publisher: Elsevier BV
Date: 03-2010
Publisher: Wiley
Date: 04-2009
Abstract: Proteomic analysis of many species of fungi, particularly filamentous fungi, is difficult due to the lack of publicly available genome sequence data and the problems associated with cross-species comparisons. Furthermore, the detection of fungal proteins in biological systems where there are a greater number of proteins present from other eukaryote species provides additional challenges. We present an EST-based approach for identifying proteins from a fungal endophyte of temperate grasses and demonstrate that this method is well suited for fungi with minimal sequence data.
Publisher: American Chemical Society (ACS)
Date: 10-12-2006
DOI: 10.1021/PR0603405
Abstract: Besides providing nutrition to the newborn, milk also protects the neonate and the mammary gland against infection. As well as the six major proteins, bovine milk contains minor proteins, not all of which have been characterized. In this study, we have subjected bovine skim milk, whey, and milk fat globule membrane (MFGM) fractions to both direct liquid chromatography-tandem mass spectrometry (LC-MS/MS), and two-dimensional electrophoresis (2-DE) followed by matrix assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry (MS) of in idual protein spots to better characterize the repertoire of minor milk proteins, particularly those involved with host defense. Milk from peak lactation as well as during the period of colostrum formation and during mastitis were analyzed to gain a more complete s ling of the milk proteome. In total, 2903 peptides were detected by LC-MS and 2770 protein spots by 2-DE. From these, 95 distinct gene products were identified, comprising 53 identified through direct LC-MS/MS and 57 through 2-DE-MS. The latter were derived from a total of 363 spots analyzed with 181 being successfully identified. At least 15 proteins were identified that are involved in host defense. These results demonstrate that the proteome of milk is more complex than has previously been reported and a significant fraction of minor milk proteins are involved in protection against infection.
Start Date: 2017
End Date: 2020
Funder: Meat and Livestock Australia
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