Extrinsic apoptosis participates to tail regression during the metamorphosis of the chordate Ciona.

Apoptosis is a regulated cell death ubiquitous in animals defined by morphological features depending on caspases. Two regulation pathways are described, currently named the intrinsic and the extrinsic apoptosis. While intrinsic apoptosis is well studied and considered ancestral among metazoans, extrinsic apoptosis is poorly studied outside mammals. Here, we address extrinsic apoptosis in the urochordates Ciona, belonging to the sister group of vertebrates. During metamorphosis, Ciona larvae undergo a tail regression depending on tissue contraction, migration and apoptosis. Apoptosis begin at the tail tip and propagates towards the trunk as a polarized wave. We identified Ci-caspase 8/10 by phylogenetic analysis as homolog to vertebrate caspases 8 and 10 that are the specific initiator of extrinsic apoptosis. We detected Ci-caspase 8/10 expression in Ciona larvae, especially at the tail tip. We showed that chemical inhibition of Ci-caspase 8/10 leads to a delay of tail regression, and Ci-caspase 8/10 loss of function induced an incomplete tail regression. The specificity between apoptotic pathways and initiator caspase suggests that extrinsic apoptosis regulates cell death during the tail regression. Our study presents rare in vivo work on extrinsic apoptosis outside mammals, and contribute to the discussion on its evolutionary history in animals.

PCR of crtNM combined with analytical biochemistry: An efficient way to identify carotenoid producing lactic acid bacteria.

Lactic acid bacteria (LAB) synthesize a wide variety of biochemical compounds during food fermentation. Carotenoids provide important biological functions for bacteria, and their consumption by humans has many beneficial effects. In this study, the presence of several genes involved in the production of carotenoids was determined by BLAST analysis and PCR in a collection of 156 LAB isolated from traditional amylaceous African fermented foods. Only the crtE gene and the crtNM operon were present and detected in Lactobacillaceae. Most of the strains with positive PCR detection of the operon crtNM produced carotenoid-like compounds when grown in MRS broth. The carotenoids produced differed from compounds previously identified in other LAB except for one peak, which was closely related to 4,4'-diaponeurosporene already reported in the literature in Lactobacillus plantarum species. Most producing strains belonged to Lactobacillus fermentum and L. plantarum species but a few Pediococcus acidilactici were also producers. Furthermore, the most efficient L. plantarum was able to synthesize carotenoids in a cereal fermented food. Genetic screening was shown to be efficient since, in all cases, it eliminated the need for biochemical analysis of strains in which no amplicons of the operon crtNM were obtained.

Influence of light exposure and oxidative status on the stability of vitamins A and D3 during the storage of fortified soybean oil.

Food fortification is implemented to address vitamins A and D deficiencies in numerous countries. The stability of vitamins A and D3 was assessed during a two-month period reproducing the usual oil storage conditions before sale to consumers. Soybean oils with different oxidative status and vitamin E contents were stored in the dark, semi-dark, or exposed to natural light. Lipid peroxidation took place after 3 weeks of storage in dark conditions. After 2 months, the vitamin A and D3 losses reached 60-68% and 61-68%, respectively, for oils exposed to natural light, and 32-39% and 24-44% in semi-dark conditions. The determining factors of vitamin A and D3 losses were (in decreasing order) the storage time, the exposure to light and the oxidative status of the oil, whereas vitamin E content had a protective role. Improving these parameters is thus essential to make vitamins A and D fortification in oils more efficient.

Assessment of a portable device to quantify vitamin A in fortified foods (flour, sugar, and milk) for quality control.

BACKGROUND: Simple-to-use quantitative methods are needed to check the adequacy of vitamin A fortification levels. OBJECTIVE: To assess the capacity of a portable fluorometer (iCheck FLUORO) and its test kit vials (iEx Mila) to quantify retinyl palmitate in fortified milks, flours (wheat, maize), and sugar. METHODS: The portable fluorometer was assessed in a three-step procedure to determine its working range and linearity, intra-assay precision, and interperson precision. Measurements were compared with the results obtained by high-performance liquid chromatography (HPLC), commonly regarded as the standard method for vitamin A analysis. RESULTS: The portable fluorometer (iCheck FLUORO) and its test kit vials (iEx Mila) precisely determined the vitamin A contents in fortifed flours, sugar, and milks. Its working range was 1 to 10, 0.5 to 3.0, and 5 to 15 mg retinol equivalents (RE) kg(-1) for flours (wheat and corn), milks, and sugar, respectively; these values are in accordance with the World Health Organization recommendations for food fortification in least developed countries. The limits of detection are higher than those of HPLC but are all satisfactory (< 1.46 mg RE kg(-1)). The coefficients of variation within and between observers were satisfactory, especially for sugar and milk. CONCLUSIONS: The linear relationship between the data from the portable fluorometer and the HPLC data confirms that the portable fluorometer provides a good determination of the vitamin A content of the fortified products in the tested range.

Quantification of vitamin A in fortified rapeseed, groundnut and soya oils using a simple portable device: comparison to high performance liquid chromatography.

Vitamin A deficiency is still one of the major public health problems in least developed countries. Fortification of vegetable oils is a strategy implemented worldwide to prevent this deficiency. For a fortification program to be effective, regular monitoring is necessary to control food quality in the producing units. The reference methods for vitamin A quantification are expensive and time-consuming. A rapid method should be useful for regular assessment of vitamin A in the oil industry. A portable device was compared to high-performance liquid chromatography (HPLC) for three plant oils (rapeseed, groundnut, and soya). The device presented a good linearity from 3 to 30 mg retinol equivalents per kg (mg RE.kg- 1). Its limits of detection and quantification were 3 mg RE.kg- 1 for groundnut and rapeseed oils and 4 mg RE.kg- 1 for soya oil. The intra-assay precision ranged from 1.48 % to 3.98 %, considered satisfactory. Accuracy estimated by the root mean squares error ranged from 3.99 to 5.49 and revealed a lower precision than HPLC (0.4 to 2.25). Although it offers less precision than HPLC, the device estimates quickly the vitamin A content of the tested oils from 3 or 4 to 15 mg RE.kg- 1.

Grid scheduling for interactive analysis.

Grids are facing the challenge of moving from batch systems to interactive computing. In the 70s, standalone computer systems have met this challenge, and this was the starting point of pervasive computing. Meeting this challenge will allow grids to be the infrastructure for ambient intelligence and ubiquitous computing. This paper shows that EGEE, the largest world grid, does not yet provide the services required for interactive computing, but that it is amenable to this evolution through relatively modest middleware evolution. A case study on medical image analysis exemplifies the particular needs of ultra-short jobs.