Beta-carotene preferentially regulates chicken myoblast proliferation withdrawal and differentiation commitment via BCO1 activity and retinoic acid production.

The enzyme ß-carotene oxygenase 1 (BCO1) catalyzes the breakdown of provitamin A, including beta-carotene (BC), into retinal, prior to its oxidation into retinoic acid (RA). Allelic variation at the BCO1 locus results in differential expression of its mRNA and affects carotenoid metabolism specifically in chicken Pectoralis major muscle. In this context, the aim of this study was to evaluate the potential myogenic effect of BC and the underlying mechanisms in chicken myoblasts. BCO1 mRNA was detected in myoblasts derived from chicken satellite cells. Treating these myoblasts with BC led to a significant decrease in BrdU incorporation. This anti-proliferative effect was confirmed by a cell cycle study using flow cytometry. BC also significantly increased the differentiation index, suggesting a positive effect on the commitment of avian myoblasts to myogenic differentiation. Addition of DEAB, a specific inhibitor of RALDH activity, significantly reduced BC anti-proliferative and pro-differentiating effects, suggesting that BC exerted its biological effect on chicken myoblasts through activation of the RA pathway. We also observed that in myoblast showing decreased BCO1 expression consecutive to a natural mutation or to a siRNA treatment, the response to BC was inhibited. Nevertheless, BCO1 siRNA transfection increased expression of BCO2 which inhibited cell proliferation in control and BC treated cells.

A simple PCR method for sexing Japanese quail Coturnix japonica at hatching.

1. The quail is a potentially important avian model for molecular studies; a major drawback is the inability to sex visually before 3 weeks of age. Molecular sexing is therefore an absolute requirement when animals are sampled before that age. 2. A low-cost method using common laboratory equipment based on Allele-Specific Multiplex-Polymerase Chain Reaction was developed to undertake reliable molecular identification of the sex of Coturnix japonica directly at hatching. 3. This simple method works with down feathers collected from behind the neck of the newly hatched quail and includes internal controls during the PCR to limit risks of error. Males and females can be discriminated on the basis of the presence of one or two amplicons, respectively.

The gastric isthmus from D+ and D- broiler lines divergently selected for digestion efficiency shows histological and morphological differences.

Previous results suggested that the gastric function plays a paramount role in digestive efficiency differences between D+ and D- broiler lines divergently selected for AMEn (more feed efficient and less feed efficient, respectively). In this paper we show an histological analysis of the gastric isthmus located between the proventriculus and the gizzard in the D+ and D- lines. Cross-sections were performed using a cryostat (Leica CM30505) and stained with a routine procedure using Mayer's Hematoxylin and Eosin Stain. The surface and shape of the constitutive gastric isthmus tissues were quantified using the image analysis software Image J. The lumen occupied 11% of the whole D- isthmus cross-sectional area against 24% for D+ (P < 0.01). The mucosa relative area (cm(2)/total cross-sectional area) was higher in D- than in D+ [47% (D-) and 39% (D+), P < 0.01]. It was significantly more oval and more folded on the lumen side in D- than in D+ chickens; the muscle layer (muscularis mucosae) of the mucosa was relatively more developed in D- than in D+ (16 and 11% of the section, respectively; P < 0.01). A relationship between these observations and increased gastric motility reported in D- compared with D+ is discussed.

A mutation in the promoter of the chicken ß,ß-carotene 15,15'-monooxygenase 1 gene alters xanthophyll metabolism through a selective effect on its mRNA abundance in the breast muscle.

A polymorphism in the promoter of the ß,ß-carotene 15,15'-monooxygenase 1 (BCMO1) gene recently was identified in an experimental cross between 2 chicken lines divergently selected on growth rate and found to be associated with variations in the yellow color of the breast meat. In this study, the effects of the polymorphism on several aspects of carotenoid metabolism were evaluated in chickens sharing the same genetic background except for their genotype at the BCMO1 locus. We confirmed that BCMO1 mRNA abundance varied (P < 0.001) between the 2 homozygous genotypes (GG << AA) and in the pectoralis major muscle. By contrast, BCMO1 mRNA expression was not affected (P > 0.05) by the polymorphism in the duodenum, liver, or sartorius muscle. The breast meat of GG chickens was more (P < 0.001) yellow and richer in lutein (P < 0.01) and zeaxanthin (P < 0.05) compared to that of AA chickens whereas these variables did not differ (P > 0.05) in the other tissues tested. The GG were also characterized by reduced (P < 0.01) plasma lutein and zeaxanthin concentrations than AA without affecting plasma and tissue content of fat-soluble vitamins A and E. As lutein and zeaxanthin are usually not considered as substrates of the BCMO1 enzyme, the impact of BCMO1 polymorphism on the activity of other genes involved in carotenoid transport (SCARB1 and CD36 encoding the scavenger receptor class B type I and the cluster determinant 36, respectively) and metabolism (BCDO2 encoding ß,ß-carotene 9',10'-dioxygenase 2) was evaluated. The BCMO1 polymorphism did not affect mRNA abundance of BCDO2, SCARB1, or CD36, regardless of tissue considered. Taken together, these results indicated that a genetic variant of BCMO1 specifically changes lutein and zeaxanthin content in the chicken plasma and breast muscle without impairing vitamin A and E metabolism.

SPG15 is the second most common cause of hereditary spastic paraplegia with thin corpus callosum.

OBJECTIVE: Hereditary spastic paraplegias (HSPs) are very heterogeneous inherited neurodegenerative disorders. Our group recently identified ZFYVE26 as the gene responsible for one of the clinical and genetic entities, SPG15. Our aim was to describe its clinical and mutational spectra. METHODS: We analyzed all exons of SPG15/ZFYVE26 gene by direct sequencing in a series of 60 non-SPG11 HSP subjects with associated mental or MRI abnormalities, including 30 isolated cases. The clinical data were collected through the SPATAX network. RESULTS: We identified 13 novel truncating mutations in ZFYVE26, 12 of which segregated at the homozygous or compound heterozygous states in 8 new SPG15 families while 1 was found at the heterozygous state in a single family. Two of 3 splice site mutations were validated on mRNA of 2 patients. The SPG15 phenotype in 11 affected individuals was characterized by early onset HSP, severe progression of the disease, and mental impairment dominated by cognitive decline. Thin corpus callosum and white matter hyperintensities were MRI hallmarks of the disease in this series. CONCLUSIONS: The mutations are truncating, private, and distributed along the entire coding sequence of ZFYVE26, which complicates the analysis of this gene in clinical practice. In our series of patients with hereditary spastic paraplegia-thin corpus callosum, the largest analyzed so far, SPG15 was the second most frequent form (11.5%) after SPG11. Both forms share similar clinical and imaging presentations with very few distinctions, which are, however, insufficient to infer the molecular diagnosis when faced with a single patient.

Adenosine monophosphate-activated protein kinase involved in variations of muscle glycogen and breast meat quality between lean and fat chickens.

The present study was aimed at evaluating the molecular mechanisms associated with the differences in muscle glycogen content and breast meat quality between 2 experimental lines of chicken divergently selected on abdominal fatness. The glycogen at death (estimated through the glycolytic potential) of the pectoralis major muscle and the quality of the resulting meat were estimated in the 2 lines. The fat chickens exhibited greater glycolytic potential, and in turn lower ultimate pH than the lean chickens. Consequently, the breast meat of fat birds was paler and less colored (i.e., less red and yellow), and exhibited greater drip loss compared with that of lean birds. In relation to these variations, transcription and activation levels of adenosine monophosphate-activated protein kinase (AMPK) were investigated. The main difference observed between lines was a 3-fold greater level of AMPK activation, evaluated through phosphorylation of AMPKalpha-(Thr(172)), in the muscle of lean birds. At the transcriptional level, data indicated concomitant down- and upregulation for the gamma1 and gamma2 AMPK subunit isoforms, respectively, in the muscle of lean chickens. Transcriptional levels of enzymes directly involved in glycogen turnover were also investigated. Data showed greater gene expression for glycogen synthase, glycogen phosphorylase, and the gamma subunit of phosphorylase kinase in lean birds. Together, these data indicate that selection on body fatness in chicken alters the muscle glycogen turnover and content and consequently the quality traits of the resulting meat. Alterations of AMPK activity could play a key role in these changes.

Treatment with a subcutaneous GnRH agonist containing controlled release device reversibly prevents puberty in bitches.

In most species, continuous administration of GnRH agonists desensitizes the pituitary to GnRH, and blocks ovarian function. The aim of this study was to assess the effects of a novel controlled release device containing azagly-nafarelin (Gonazon) to prevent puberty in young Beagle bitches (mean age: 4.88 +/- 0.32 months). Gonazon containing 18.5 mg azagly-nafarelin (n = 10) or a placebo implant (n = 10) was administered subcutaneously. Throughout the 1-year treatment, estrus behaviour was monitored weekly. Plasma progesterone concentrations, as well as body weight and height, were measured monthly. Following implant removal, estrus detection and progesterone measurement were continued until occurrence of puberty in all bitches. Control bitches displayed puberty (estrus, followed by ovulation) at approximately 11.9 +/- 2.7 (range, 8-16) months of age. In contrast, none of the Gonazon treated bitches displayed puberty during the period when Gonazon was present. Following removal of Gonazon, resumption of estrus and ovulation naturally occurred (seven bitches) or was induced (three bitches) approximately 8.5 (1.2-14.3) months later. As a consequence, age of puberty of the Gonazon treated bitches was 25.5 +/- 5 (18-31) months. No clinically detectable side effects were noted in Gonazon treated bitches. Height at withers was unaffected by treatment. Changes in body weight with time were also unaffected by treatment. Implants were well tolerated and generally easy to remove. These data demonstrated that Gonazon safely, efficiently and reversibly prevents reproductive function for 1 year in prepubertal bitches.

Autoimmune hepatitis and multiple sclerosis: a coincidental association?

In the present study we report, as part of a large multiple sclerosis (MS) cohort (1800 patients), three cases of untreated patients who developed autoimmune hepatitis (AIH). The prevalence of AIH in the general population is about 0.0169% and seems to be higher in our MS cohort (0.17%). We suggest that a liver biopsy should systematically be performed in untreated MS patients with a sustained increase of liver enzyme.

Morphogenesis of the optic tectum in the medaka (Oryzias latipes): a morphological and molecular study, with special emphasis on cell proliferation.

We analyzed the medaka optic tectum (OT) morphogenesis by using 5-bromo-2'-deoxyuridine (BrdU) immunohistochemistry (with a new method we developed for pulse-labeling embryos) and in situ hybridization with three probes, two for recently cloned homeobox genes (Ol-Prx3 [Paired-Related-Homeobox3] and Ol-Gsh1 [Genetic-Screen-Homeobox1]) and one for Ol-tailless. The tectal anlage first appears as a sheet of proliferating cells expressing Ol-Gsh1 and Ol-tailless but not Ol-Prx3. Cells subsequently cease to proliferate in a superficial and rostral zone and begin to express Ol-Prx3. When tectal lamination begins, the proliferative zone (mpz) becomes restricted to a crescent at the OT medial, caudal, and lateral margin. This mpz functions throughout the fish's entire life. It produces cells that are added at the OT's edge as radial rows, spanning every layer of the OT. The cells of the mpz continue to express Ol-tailless in the adult, whereas Ol-Gsh1 expression is turned off. When superficial layers form, Ol-Prx3 expression becomes restricted to the underlying deep layer, where it persists in the adult. Ol-Prx3 seems to be a marker for the differentiation of a subset of deep cells and allows analysis of tectal lamination, whereas Ol-tailless and Ol-Gsh1 could be involved in the control of tectal cell proliferation. This study constitutes a first step toward molecular approach to OT development in anamniotes. We compare and discuss the expression patterns of the homologs of the genes studied, and more generally the morphogenetic patterns of the medaka tectum, with those encountered in other cortical structures and in other vertebrate groups.