Mouse tafazzin is required for male germ cell meiosis and spermatogenesis

Barth syndrome is an X-linked mitochondrial disease, symptoms of which include neutropenia and cardiac myopathy. These symptoms are the most significant clinical consequences of a disease, which is increasingly recognised to have a variable presentation. Mutation in the Taz gene in Xq28 is thought to be responsible for the condition, by altering mitochondrial lipid content and mitochondrial function. Male chimeras carrying a targeted mutation of Taz on their X-chromosome were infertile. Testes from the Taz knockout chimeras were smaller than their control counterparts and this was associated with a disruption of the progression of spermatocytes through meiosis to spermiogenesis. Taz knockout ES cells also showed a defect when differentiated to germ cells in vitro. Mutant spermatocytes failed to progress past the pachytene stage of meiosis and had higher levels of DNA double strand damage and increased levels of endogenous retrotransposon activity. Altogether these data revealed a novel role for Taz in helping to maintain genome integrity in meiosis and facilitating germ cell differentiation. We have unravelled a novel function for the Taz protein, which should contribute to an understanding of how a disruption of the Taz gene results in the complex symptoms underlying Barth Syndrome

Effects of animal type, handling, and transportation conditions on beef cattle temperament pre-slaughter

ABSTRACT This study aimed to investigate the effects of animal type, on-farm handling, and transport conditions on temperament of beef cattle pre-slaughter. The study evaluated 4,061 cattle batches, averaging 49 animals, with a total of 199,026 cattle. Temperament was evaluated through a behavioral assessment carried out based on the temperament shown by cattle when approached by humans. One of three different temperament scores were assigned to each batch: calm, anxious, or excitable. Excitable temperament was reported in animals subjected to long transport time and distance and high loading density. The degree of carcass fatness was higher in calm animals, followed by anxious animals, with the excited temperament animals having the lowest carcass fatness degree. Older animals showed more excitable temperament, while younger animals showed calmer temperament. The excitable temperament was more evident in horned animals in relation to polled animals. Animal temperament was more reactive in batches with older cattle, low carcass fatness degree, and with more than 20% horned animals. Good handling and loading facilities and procedures at the farm contributed to adequate cattle temperament expression prior to slaughter