Browsing by Author "Wehrle-Martinez AS"

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    Insights into the pathogenesis of catastrophic spontaneous humeral fractures in first-lactation dairy cows
    (CSIRO Publishing, Australia, 2025-05-06) Wehrle-Martinez AS; Lawrence KE; Back PJ; Rogers CW; Gibson MJ; Dittmer KE; Eastwood C
    Spontaneous humeral fractures in first-lactation dairy cows have introduced significant challenges to the dairy industry in New Zealand, impacting animal welfare, farm economics, and veterinary practices. This review synthesizes current knowledge on the pathogenesis of these fractures and identifies potential key risk factors. The majority of bones from affected first-lactation dairy cows have osteoporosis, which is associated with inadequate bone formation and increased bone resorption. In addition, low total collagen content in bones from most affected dairy cows supports the hypothesis that inadequate bone formation is an important risk factor associated with humeral fractures in these cows. Spectroscopic analyses further confirmed a significant reduction in bone quality and strength. Novel findings suggest that low liver copper concentration in many of the affected cows' results from the mobilisation of copper to the bone. Although limited, the accumulated evidence suggests that to mitigate the incidence of catastrophic fractures, adequate nutrition (especially protein-energy) should be supplied during important growth periods. While significant progress has been made in understanding the cause of these fractures, many uncertainties and areas requiring further research remain.
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    Recurrent horizontal transfer identifies mitochondrial positive selection in a transmissible cancer.
    (Springer Nature Limited, 2020-06-16) Strakova A; Nicholls TJ; Baez-Ortega A; Ní Leathlobhair M; Sampson AT; Hughes K; Bolton IAG; Gori K; Wang J; Airikkala-Otter I; Allen JL; Allum KM; Arnold CL; Bansse-Issa L; Bhutia TN; Bisson JL; Blank K; Briceño C; Castillo Domracheva A; Corrigan AM; Cran HR; Crawford JT; Cutter SM; Davis E; de Castro KF; De Nardi AB; de Vos AP; Delgadillo Keenan L; Donelan EM; Espinoza Huerta AR; Faramade IA; Fazil M; Fotopoulou E; Fruean SN; Gallardo-Arrieta F; Glebova O; Gouletsou PG; Häfelin Manrique RF; Henriques JJGP; Horta RS; Ignatenko N; Kane Y; King C; Koenig D; Krupa A; Kruzeniski SJ; Lanza-Perea M; Lazyan M; Lopez Quintana AM; Losfelt T; Marino G; Martínez Castañeda S; Martínez-López MF; Masuruli BM; Meyer M; Migneco EJ; Nakanwagi B; Neal KB; Neunzig W; Nixon SJ; Ortega-Pacheco A; Pedraza-Ordoñez F; Peleteiro MC; Polak K; Pye RJ; Ramirez-Ante JC; Reece JF; Rojas Gutierrez J; Sadia H; Schmeling SK; Shamanova O; Sherlock AG; Steenland-Smit AE; Svitich A; Tapia Martínez LJ; Thoya Ngoka I; Torres CG; Tudor EM; van der Wel MG; Vițălaru BA; Vural SA; Walkinton O; Wehrle-Martinez AS; Widdowson SAE; Zvarich I; Chinnery PF; Falkenberg M; Gustafsson CM; Murchison EP
    Autonomous replication and segregation of mitochondrial DNA (mtDNA) creates the potential for evolutionary conflict driven by emergence of haplotypes under positive selection for 'selfish' traits, such as replicative advantage. However, few cases of this phenomenon arising within natural populations have been described. Here, we survey the frequency of mtDNA horizontal transfer within the canine transmissible venereal tumour (CTVT), a contagious cancer clone that occasionally acquires mtDNA from its hosts. Remarkably, one canine mtDNA haplotype, A1d1a, has repeatedly and recently colonised CTVT cells, recurrently replacing incumbent CTVT haplotypes. An A1d1a control region polymorphism predicted to influence transcription is fixed in the products of an A1d1a recombination event and occurs somatically on other CTVT mtDNA backgrounds. We present a model whereby 'selfish' positive selection acting on a regulatory variant drives repeated fixation of A1d1a within CTVT cells.