Periconceptional undernutrition (PCUN) results in an earlier prepartum activation of the pituitary-adrenal axis in twin compared with singleton fetuses. We have tested the hypotheses that the functional development of the fetal sheep adrenal is delayed in twins compared with singletons in early gestation and that PCUN accelerates adrenal growth and increases the expression of intraadrenal IGF-I and -II and cytochrome P450 17-hydroxylase (CYP17) as early as 55 d gestation. We have investigated the effect of PCUN in the ewe (restricted at 70% of control allowance, n=21; control, n=24) from at least 45 d before mating until d 7 after mating on maternal cortisol and progesterone concentrations, fetal adrenal weight, adrenal IGF-I, IGF-I receptor (IGF-IR), IGF-II, IGF-IIR, and CYP17 mRNA expression and placental 11beta-hydroxysteroid dehydrogenase-1 and -2 mRNA and protein expression at d 53-56 pregnancy. The relative weight of the fetal adrenal and adrenal IGF-I, IGF-IR, IGF-II, IGF-IIR, and CYP17 mRNA expression were lower in twin compared with singleton fetuses. In singleton fetuses of PCUN ewes, there was a loss of the relationship between adrenal IGF-II/IGF-IIR expression and either adrenal weight or CYP17 mRNA, which was present in controls. Similarly in twin fetuses, PCUN resulted in the loss of the relationships between adrenal weight and IGF-I expression and between adrenal CYP17 and IGF-II expression, which were present in controls. Our findings suggest that differences in the timing of the prepartum activation of the fetal adrenal in twins and singletons have their origins in early gestation and highlight the importance of the interaction between the periconceptional environment and embryo number in setting the growth trajectory of the fetal adrenal.
The immobilization of natural photosystem II (PSII) enzyme onto an artificial electrode offers an ingenious and promising avenue for semiartificial solar energy conversion. However, this process is significantly limited by the poor stability and the short life of PSII. Here, a new prototype of a semiartificial system is reported by anchoring PSII on polyethylenimine‐coated macroporous carbon electrode with a high load. Good electronic communication is established at the biointerface of this PSII electrode, enabling excellent photoelectrochemical (PEC) water oxidation and lasting electricity generation. The maximum turnover number of 10 200 ± 1380 mol O2 per mol PSII dimer is obtained in this system at around 10 h before complete deactivation, reaching high current‐to‐O2 conversion efficiencies. The functions of PSII to release O2 both in light and dark conditions as well as for H2O2 formation are revealed. Under periodic irradiation (AM 1.5G 1 sun), this PSII electrode allows for stable mediated photocurrent output of ≈4.31 µA cm−2 after five days, which represents the most stable photoelectric performance achieved so far for PSII‐related electrodes.
In vitro culture (IVC) systems feature commonly in reproductive technologies used in livestock. However, these culture conditions impact on the metabolism and physiology of the developing embryos, as well as on fetal outcome. Culturing rodent embryos in simple defined media results in decreased postimplantation viability and fetal growth rate.1,2 Cytokines and growth factors are present in vivo but are absent from culture and may be causal in the perturbed fetal growth observed. Furthermore, the occurrence of large offspring syndrome (LOS) following embryo IVC in ruminants has been reported and is associated with loss of genetic imprinting.3,4 Abnormal placental development following IVC is also likely to involve perturbed expression of imprinted genes including insulin-like growth factor II (IGF2) and its receptor (IGF2R). The IVC system used for this study included a control embryo transfer group without culture (ET, n = 11), in vitro cultured embryos in serum free defined medium (IVC-NS, n = 10) and in vitro cultured embryos in defined medium with human serum (IVCHS, n = 8). The cultured embryos were transferred to recipient ewes and placentomes were collected at 144–145 days gestation. Fetal weight (kg) was increased in IVCHS (5.15 ± 0.28) compared to ET (4.12 ± 0.24, P = 0.017) and IVC-NS (4.36 ± 0.27). Real-time RT-PCR was used to quantify IGF2 and IGF2R mRNA expression normalized to housekeeper RpP0. Although IGF2 expression was increased in the IVCHS group (2.27 ± 0.44) when compared to ET (1.22 ± 0.37) and IVC-NS (1.17 ± 0.43) groups, this was not significant. In addition, IGF2R expression was increased in the IVCHS (0.008 ± 0.003) group compared to ET (0.003 ± 0.001) and IVC-NS (0.004 ± 0.001) groups, but this was also not significant. IGF2 and IGF2R expression were, however, positively correlated in IVCNS (r = 0.72) and IVCHS (r = 0.95) placentomes, but not control ET placentomes. The presence of serum in IVC promoted fetal growth and increased expression of IGF2 and IGF2R mRNA in placental tissue. Comparison of placental gene expression from IVCHS and naturally mated pregnancies would be valuable to assess the role of serum in placental and fetal development.
(1)Bowman & McLaren, 1970.(2)Kaye & Gardner, 1999.(3)Thompson et al., 1995.(4)Young et al., 1998.
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