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F Berthelot

Publications and source records attributed to F Berthelot.

27 records · Page 2Linked to original sources
PubMed1977

Poly(A)-containing RNA in neuroblastoma: immature and differentiated cells in culture.

We have analysed the poly(A)-containing RNA from neuroblastoma cells at two different developmental states: either as round, immature neuroblasts grown in suspension, or as differentiated cells exhibiting the morphological properties of mature neurons, when attached to a culture dish. Suspension-grown and monolayer cells were pulse-labelled with tritiated uridine. The profile of cytoplasmic poly(A)-containing RNA from suspension cells is highly heterogeneous with peaks ranging from 16-30 S. The profile obtained from differentiated cells appears somewhat distinct from the previous one. This is evidenced by a relative decrease in the 26-S peak and a virtual disappearance of the 16-S component. In order to compare the 'steady-state' patterns of poly(A)-containing RNA in these two developmental stages, polysomal RNA was prepared from unlabelled cells. Following sucrose gradient sedimentation, each fraction was hybridized to [3H]poly(U). Examination of the two RNA hybridization profiles reveals striking similarities suggesting that 'steady-state' messenger populations include, on the average, the same subspecies. The 16-S fraction, which was not observed after the pulse-labelling of the monolayer culture, is detected here by hybridization to [3H]poly(U) when using polysomal poly(A)-containing RNA from monolayer cells as substrate. These results suggest that terminal differentiation of neuroblastoma cells is not accompanied by major alterations of the transcription program and is paralleled by a marked stabilization of the 16-S species.

Cell Differentiation↗
PubMedDate not supplied

Birth of piglets after OPS vitrification and transfer of compacted morula stage embryos with intact zona pellucida.

In swine, five to six days post-insemination, morulae and blastocysts are collected together after uterine flushing. The purpose of this study was to vitrify zona pellucida-intact morulae with Open Pulled Straw (OPS) technology and obtain piglets after transfer. Morulae (200) were vitrified after a two-step equilibration in ethylene glycol, dimethyl sulfoxide and sucrose in Hepes-buffered TCM199 + 20% NBCS medium (TCM). 2-6 morulae were loaded into OPS and plunged into liquid nitrogen. At embryo warming, a three-step dilution with decreasing concentrations of sucrose was applied. In each of 10 recipients, 20 morulae were transferred surgically. Day 25, gestation rate and the farrowing rate were 80% and 70%, respectively. The pregnant recipients farrowed from 1 to 8 piglets and the survival of total transferred embryos was 13%. Although survival rates are still compromised, OPS technology is therefore appropriate to cryopreserve porcine morulae with intact zona pellucida.

Animals↗
PubMedDate not supplied

Differences in frequency, level, and duration of cecal carriage between four outbred chicken lines infected orally with Salmonella enteritidis.

Four chicken lines, L2, B13, PA12 (egg-type), and Y11 (meat-type), were tested for experimental carrier state of Salmonella enteritidis (SE) in two identical trials. After oral inoculation of SE at 1 wk of age with 5 x 10(4) SE colony-forming units (CFU), 10 chickens per line were necropsied weekly for 6 wk and then every 8 or 15 days until the 12th week postinoculation (PI). Liver, spleen, ovary, and ceca were examined for level of SE colonization. Numbers of positive livers and spleens and levels of the challenge strain in these organs differed little between the four chicken lines. Only three positive ovaries were detected. According to the chicken line, ceca exhibited generally significant (P < 0.05) differences in the number of positive organs during weeks 5-11 PI, in the SE CFU levels (P < 0.05) in the first 5 wk PI and during weeks 8 and 10 PI, and in the duration of colonization. L2 and B13 chickens generally carried SE in their ceca at higher levels, in more animals, and for a longer time than PA12 and Y11 chickens. Y11 chickens were the most resistant to SE cecal colonization.

Animals↗
PubMedDate not supplied

Variability in the resistance of four chicken lines to experimental intravenous infection with Salmonella enteritidis phage type 4.

The capacity of four chicken lines (Y11, L2, B13, PA12) to control Salmonella enteritidis (SE) phage type 4 (PT4) systemic colonization was investigated. Thirteen-week-old chickens were intravenously inoculated with 10(6) SE colony-forming units, and the levels of SE colonization were determined at various time intervals after inoculation in liver, spleen, genital organs, and ceca. The course of SE infection showed a rapid contamination of liver, spleen, and genital organs, whereas the ceca were infected later. A significant (P < 0.001) effect of the chicken line on levels of SE was detected on day 3 postinoculation (PI) in liver and ceca, on day 10 PI in ceca, and on day 15 PI in spleen. Because an early control of systemic Salmonella infection by the Ity/Nramp1 gene has been demonstrated in mice, we aimed to study the early resistance of chickens to SE. As a consequence, we then focused our study on the between- and within-line variabilities of SE levels on day 3 PI. According to the SE levels in liver on day 3 PI, the chicken lines could be classified as susceptible (Y11 and L2) or resistant (PA12 and B13). This early variability was explored in resistant B13 and susceptible L2 lines. Differences between these two lines were confirmed in liver but not in ceca. A large within-line variability was observed in all organs of these two lines. The genetic origin of this variability will have to be determined as a prerequisite to an eventual selection.

Animals↗