Lack of functional alpha-lactalbumin prevents involution in Cape fur seals and identifies the protein as an apoptotic milk factor in mammary gland involution

The mammary gland undergoes a sophisticated programme of developmental changes during pregnancy/lactation. However, little is known about processes involving initiation of apoptosis at involution following weaning. We used fur seals as models to study the molecular process of involution as these animals display a unique mammary gland phenotype. Fur seals have long lactation periods whereby mothers cycle between secreting copious quantities of milk for 2 to 3 days suckling pups on land, with trips to sea alone to forage for up to 23 days during which time mammary glands remain active without initiating apoptosis/involution.<br /

Generating mice with targeted mutations.

Journal ArticleMutational analysis is one of the most informative approaches available for the study of complex biological processes. It has been particularly successful in the analysis of the biology of bacteria, yeast, the nematode worm Caenorhabditis elegans and the fruit fly Drosophila melanogaster. Extension of this approach to the mouse, through informative, was far less successful relative to what has been achieved with these simpler model organisms. This is because it is not numerically practical in mice to use random mutagenesis to isolate mutations that affect a specified biological process of interest. Nonetheless, biological phenomena such as a sophisticated immune response, cancer, vascular disease or higher-order cognitive function, to mention just a few, must analyzed in organisms that show such phenomena, and for this reason geneticists and other researchers have turned to the mouse. Gene targeting, the means for creating mice with designed mutations in almost any gene, was developed as an alternative to the impractical use of random mutgenesis for pursing genetic analysis in the mouse. Now gene targeting has advanced the genomic manipulations possible in mice to a level that can be matched only in far simple organisms such as bacteria and yeast

Non-Invasive In Vivo Imaging of Calcium Signaling in Mice

Rapid and transient elevations of Ca2+ within cellular microdomains play a critical role in the regulation of many signal transduction pathways. Described here is a genetic approach for non-invasive detection of localized Ca2+ concentration ([Ca2+]) rises in live animals using bioluminescence imaging (BLI). Transgenic mice conditionally expressing the Ca2+-sensitive bioluminescent reporter GFP-aequorin targeted to the mitochondrial matrix were studied in several experimental paradigms. Rapid [Ca2+] rises inside the mitochondrial matrix could be readily detected during single-twitch muscle contractions. Whole body patterns of [Ca2+] were monitored in freely moving mice and during epileptic seizures. Furthermore, variations in mitochondrial [Ca2+] correlated to behavioral components of the sleep/wake cycle were observed during prolonged whole body recordings of newborn mice. This non-invasive imaging technique opens new avenues for the analysis of Ca2+ signaling whenever whole body information in freely moving animals is desired, in particular during behavioral and developmental studies

A genome scan for milk production traits in dairy goats reveals two new mutations in <i>Dgat1</i> reducing milk fat content

The quantity of milk and milk fat and proteins are particularly important traits in dairy livestock. However, little is known about the regions of the genome that influence these traits in goats. We conducted a genome wide association study in French goats and identified 109 regions associated with dairy traits. For a major region on chromosome 14 closely associated with fat content, the Diacylglycerol O-Acyltransferase 1 (DGAT1) gene turned out to be a functional and positional candidate gene. The caprine reference sequence of this gene was completed and 29 polymorphisms were found in the gene sequence, including two novel exonic mutations: R251L and R396W, leading to substitutions in the protein sequence. The R251L mutation was found in the Saanen breed at a frequency of 3.5% and the R396W mutation both in the Saanen and Alpine breeds at a frequencies of 13% and 7% respectively. The R396W mutation explained 46% of the genetic variance of the trait, and the R251L mutation 6%. Both mutations were associated with a notable decrease in milk fat content. Their causality was then demonstrated by a functional test. These results provide new knowledge on the genetic basis of milk synthesis and will help improve the management of the French dairy goat breeding program

The deleterious effects of human erythropoietin gene driven by the rabbit whey acidic protein gene promoter in transgenic rabbits

International audienc

The Formation of an Anti-Cancer Complex Under Simulated Gastric Conditions

This is the author’s version of a work that was accepted for publication in Food Digestion. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Food Digestion, 2013, 4(1), 7-18. The final publication is available at http://link.springer.com, DOI: 10.1007/s13228-012-0030-0.peer-reviewedA potent anti-cancer complex has previously been formed from two major components of milk. Human/bovine α-lactalbumin made lethal to tumour cells (H/BAMLET) is a protein–fatty acid complex that has been produced using the whey protein α-lactalbumin (α-LA) and the fatty acid oleic acid (OA). It was shown that it possesses selective anti-tumour and anti-microbial activity, which was first identified in acidic fractions of human breast milk. The aim of this study was to determine whether the two components would form a bioactive complex during simulated gastric (GI) transit. Results showed that a complex consisting of α-LA and OA is formed as the protein unfolds under acidic conditions and subsequently refolds upon pH increase. Analysis of this complex using Nuclear Magnetic Resonance and Fourier Transform Infra-Red (FTIR) spectroscopies estimated a stoichiometry of 4.1 and 4.4 oleic acids per mole of protein, respectively. FTIR and fluorescence spectroscopies showed that the structure was similar to that of BAMLET. Cytotoxicity testing against cancer cell line U937 cells showed that the complex had an LC50 value of 14.08 μM compared to 9.15 μM for BAMLET. These findings suggest that a BAMLET-like complex may be formed under the tested in vitro GI conditions.Department of Agriculture, Food and Marine, Ireland - Food Institutional Research Measure (project number 08RDTMFRC650); Teagasc Walsh Fellowship scheme; COST Action FA 1005, Infogest