Molecular Growth Requirements of Single Mammalian Cells

The molecular nutritional requirements exhibited by mammalian cells can vary with the following conditions: whether the cells are plated singly or in massive inoculum; whether a clonal strain or a mixture of different genotypes is employed; whether the macromolecular fraction of serum used as a supplement was previously exposed to prolonged dialysis or other procedures which may release bound micromolecules. In addition, the nature of the medium in which the cells were previously grown, the time permitted for incubation of the cells in the test medium, and the presence of substances or conditions which may specifically introduce the need for certain molecules to preserve balance can strongly influence nutritional requirements. This great versatility may reflect the ability of the mammalian cell to assume different metabolic states characteristic of specific types of differentiation. Under certain conditions, growth of single HeLa cells of the S3 clonal strain requires the presence of cholesterol at a level of 0.5 to 1 microgram per milliliter.     

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4.0、3.0和2.0,她们之间本不应该有交点,但因为对网球的痴迷程度都是7.0,于是这三个在各自圈子里红得发烫的人,走到了一起。     

High Periconceptional Protein Intake Modifies Uterine and Embryonic Relationships Increasing Early Pregnancy Losses and Embryo Growth Retardation in Sheep

The effects of supplemented protein level (PL) during the periconceptional period and their interaction with body condition were evaluated in sheep. Multiparous Rambouillet ewes (n = 12) received two PL of rumen undegradable protein (UIP) during a 30‐day pre‐mating and 15‐day post‐mating period: low [LPL, 24% crude protein (CP), 14 g UIP and 36 g/CP animal/day] and high [HPL, 44% CP, 30 g UIP and 50 g/CP animal/day]. While ovulation rate (OR) did not differ between treatments (1.6 ± 0.5, mean ± SEM), a lower fertility rate, a decreased embryo number and a reduced uterine pH (UpH) was observed in the HPL group (p < 0.05), irrespective of BC. Luteal tissue weight, volume and progesterone secretion did not differ among treatments. Sheep with lower UpH also had lower conceptus weight (Cwt; p < 0.05, r = 0.65) and conceptuses with lower mass tended to secrete less INF‐τ and IGF‐1, and the correspondent endometrial explants had a higher basal PGF_2α release. Current study indicates that high protein diets during the periconceptional period in sheep modify uterine and embryonic relationships, increasing early pregnancy losses and inducing embryo growth retardation. Surviving embryos were affected by weight reductions, which could compromise later foetal growth and birth weight. Results evidence the key role of a balanced diet in reproductive success and indicate that the quality and nutrient composition of the maternal diet are essential for an adequate establishment of pregnancy, having paramount effects on the interplay of the embryo and the uterus.     

Detection of inborn errors of metabolism: galactosemia

Radioautography of cultured, human, galactosemic and nongalactosemic cells shows that, in the presence of 0.05M D-galactono-gamma-lactone, the former incorporate much less galactose in acid-insoluble form than the latter. Presumably the lactone inhibits incorporation of the labeled galactose into pathways which do not require galactose-1-phosphate uridylyltransferase activity. Definite differences between the galactosemic and nongalactosemic condition can be demonstrated with as few as 100 to 1000 cells. This approach may be useful in facilitating prenatal detection of several kinds of inborn errors of metabolism.