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Background Ovarian follicles, which are the basic units of female reproduction, are composed of oocytes and surrounding somatic (pre) granulosa cells (GCs). A recent study revealed that signaling in somatic preGCs controlled the activation (initial recruitment) of follicles in the adult ovaries, but it is also known that there are two waves of follicle with age-related heterogeneity in their developmental dynamics in mammals. Although this heterogeneity was proposed to be crucial for female reproduction, our understanding of how it arises and its significance is still elusive. Results In the current study, by deleting the key secreted factor KIT ligand from preGCs and analyzing the follicle cell developmental dynamics, we revealed distinct patterns of activation and growth associated with the two waves of follicles in mouse ovary. Our results confirmed that activation of adult wave follicles is initiated by somatic preGCs and dependent on the KIT ligand. By contrast, activation of first wave follicles, which are awakened from germ cells before follicle formation, can occur in the absence of preGC-secreted KIT ligand in postnatal ovaries and appears to be oocyte-initiated. We also found that the asynchronous activity of phosphatidylinositol 3 kinases (PI3K) signaling and meiotic process in embryonic germ cells lead to the follicle heterogeneity in postnatal ovaries. In addition, we supplied evidence that the time sequence of embryonic germ cell development and its related first wave follicle growth are correlated to the time of puberty onset in females. Conclusion Taken together, our study provides evidence that asynchronous development of embryonic oocytes leads to the heterogeneity of postnatal ovarian follicle activation and development, and affects the timing of onset of puberty in females.

Crosstalk between oocytes and surrounding somatic cells is crucial for mammalian oogenesis, but the structural mechanisms on oocytes to control female reproduction remain unknown. Here we combine endogenous-fluorescent tracing mouse models with a high-resolution live-cell imaging system to characterize oocyte-derived mushroom-like microvilli (Oo-Mvi), which mediate germ-somatic communication in mice. We perform 3D live-cell imaging to show that Oo-Mvi exhibit cellular characteristics that fit an exocrine function for signaling communication. We find that deletion of the microvilli-forming gene Radixin in oocytes leads to the loss of Oo-Mvi in ovaries, and causes a series of abnormalities in ovarian development, resulting in shortened reproductive lifespan in females. Mechanistically, we find that Oo-Mvi enrich oocyte-secreted factors and control their release, resulting in optimal selection of ovarian follicles. Taken together, our data show that the Oo-Mvi system controls the female reproductive lifespan by governing the fate of follicles., How structural features on oocytes regulate mammalian female reproduction is unclear. Here, the authors provide imaging and physiological evidence (for example on Radixin knockout) to identify oocyte-derived mushroom-like microvilli that control the female reproductive lifespan by governing the fate of follicles.

The myeloid differentiation factor 88 (MyD88) is the most common adaptor protein in toll-like receptor (TLR) signaling pathways and plays an important role in the innate immune system. In this report, we conducted rapid amplification of complementary DNA (cDNA) ends (RACE), multiple sequence alignment, conserved domain search, phylogenetic tree construction, and quantitative real-time PCR to obtain and analyze the full-length cDNA sequence, the amino acid sequential structures, and the expression patterns of Rana dybowskii (Rd) MyD88. The full-length cDNA of RdMyD88 is 1472 bp, with an open reading frame of 855 bp, encoding a protein of 285 amino acid residues. The RdMyD88 amino acid sequence contains a death domain (DD) and a Toll/interleukin-1 receptor (TIR) domain. RdMyD88 was calculated as a hydrophilic protein with predicted molecular mass and pI of 32.79 kDa and 6.00, respectively. Eighteen possible phosphorylation sites including eight serine residues, six tyrosine residues, and four threonine residues are predicted. Analysis of multiple sequence alignment and phylogenetic tree revealed that the predicted RdMyD88 protein is closest to its Xenopus counterparts. The PCR result showed that RdMyD88 is expressed in various tissues of R. dybowskii. Quantitative real-time PCR (qPCR) was used to examine the expression of RdMyD88 in the heart, liver, and kidney. After Rana grylio virus (RGV) exposure, the expression of RdMyD88 in the heart, liver, and kidney were significantly upregulated and reached peak levels at 48, 48, and 72 h post-infection (hpi), respectively. Meanwhile, in response to Aeromonas hydrophila (AH) infection, clear upregulation of RdMyD88 was observed in the heart, liver, and kidney and reached its peak at 48, 6, and 12 hpi, respectively. The highest levels of induction were found in the kidney after both RGV and AH infections. These findings indicate that RdMyD88 has a conserved structure and is probably an important component of the innate immunity in R. dybowskii. This report firstly characterized one adaptor molecule of the TLR signaling pathways in R. dybowskii, thereby providing reference for further researches on the amphibian innate immune system.

Objective This study was conducted to evaluate the percutaneous absorption of aconitine and mesaconitine in extracts of Radix Aconitum kusnezoffii. Methods The extracts of Radix Aconitum kusnezoffii were collected by using Franz diffusion cells after permeation through the skin of rats. Then rate constants of skin permeation of aconitine and mesaconitine were determined by high-performance liquid chromatography (HPLC). Results Under the condition that the concentrations of azone and propylene glycol were both 4%, the cumulative doses of skin permeation (Q) of mesaconitine and aconitine in the extracts of Radix Aconitum kusnezoffii (600 mg/ml) for 24 hours were 165.819 and 487.747 microg/cm(2) respectively, and their rate constants of skin permeation were 18.391 and 78.805 microg.cm(-2).h(-1) respectively. Conclusion The aconitine and mesaconitine in the extracts of Radix Aconitum kusnezoffii can penetrate well through the skin of rats. Propylene glycol and azone can promote this penetration effects. The formula of skin permeation of mesaconitine and aconitine is in accordance with Higuchi equation and there is a linear relationship between Q and t(1/2).