High genetic diversity and low population differentiation of a medical plant Ficus hirta Vahl., uncovered by microsatellite loci: implications for conservation and breeding.

BACKGROUND: Wuzhimaotao (Radix Fici Hirtae) originates from the dry root of Ficus hirta (Moraceae), which is widely known as a medical and edible plant distributed in South China. As the increasing demand for Wuzhimaotao, the wild F. hirta has been extremely reduced during the past years. It is urgent to protect and rationally develop the wild resources of F. hirta for its sustainable utilization. However, a lack of genetic background of F. hirta makes it difficult to plan conservation and breeding strategies for this medical plant. In the present study, a total of 414 accessions of F. hirta from 7 provinces in southern China were evaluated for the population genetics using 9 polymorphic SSR markers. RESULTS: A mean of 17.1 alleles per locus was observed. The expected heterozygosity (He) varied from 0.142 to 0.861 (mean = 0.706) in nine SSR loci. High genetic diversity (He = 0.706, ranged from 0.613 to 0.755) and low genetic differentiation among populations (G'ST = 0.147) were revealed at population level. In addition, analysis of molecular variance (AMOVA) indicated that the principal molecular variance existed within populations (96.2%) was significantly higher than that among populations (3.8%). Meanwhile, the three kinds of clustering methods analysis (STRUCTURE, PCoA and UPGMA) suggested that the sampled populations were clustered into two main genetic groups (K = 2). Mantel test showed a significant correlation between geographic and genetic distance among populations (R2 = 0.281, P < 0.001). Pollen flow, seed flow and/or geographical barriers might be the main factors that formed the current genetic patterns of F. hirta populations. CONCLUSIONS: This is a comprehensive study of genetic diversity and population structure of F. hirta in southern China. We revealed the high genetic diversity and low population differentiation in this medicinal plant and clarified the causes of its current genetic patterns. Our study will provide novel insights into the exploitation and conservation strategies for F. hirta.

Limited genetic diversity and high differentiation in Angelica dahurica resulted from domestication: insights to breeding and conservation.

BACKGROUND: Angelica dahurica belongs to the Apiaceae family, whose dry root is a famous traditional Chinese medicine named as "Bai zhi". There are two cultivars (A. dahurica cv. 'Hangbaizhi' and A. dahurica cv. 'Qibaizhi'), which have been domesticated for thousands of years. Long term artificial selection has led to great changes in root phenotypes of the two cultivars, and also decreased their adaptability to environment. We proposed hypothesis that the cultivars may have lost some of the genetic diversity found in the wild species and may be highly differentiated from the latter during the domestication process. However, few studies have been carried out on how domestication affected the genetic variation of this species. Here, we accessed the levels of genetic variation and differentiation within and between wild A. dahurica populations and two cultivars using 12 microsatellite markers. RESULTS: The results revealed that the genetic diversity of the cultivars was much lower than that of wild A. dahurica, and A. dahurica cv. 'Qibaizhi' had lower genetic diversity compared to A. dahurica cv. 'Hangbaizhi'. AMOVA analysis showed significant genetic differentiation between the wild and cultivated A. dahurica populations, and between A. dahurica cv. 'Hangbaizhi' and A. dahurica cv. 'Qibaizhi'. Results from Bayesian, UPGMA, NJ and PcoA clustering analysis indicated that all 15 populations were assigned to two genetic clusters corresponding to the wild and cultivated populations. Bayesian clustering analysis further divided the cultivated populations into two sub-clusters corresponding to the two cultivars. CONCLUSIONS: Our study suggests that the domestication process is likely the major factor resulting in the loss of genetic diversity in cultivated A. dahurica populations and in significant genetic differentiation from the wild populations due to founder effect and/or artificially directional selections. This large-scale analysis of population genetics could provide valuable information for genetic resources conservation and breeding programs of Angelica dahurica.

Sphingosine-1-phosphate activates the AKT pathway to inhibit chemotherapy induced human granulosa cell apoptosis.

To investigate whether sphingosine-1-phosphate (S1P), an apoptosis-inhibitor would be able to inhibit chemotherapy induced human granulosa cell apoptosis. Cultures of primary granulosa cells were isolated from women undergoing in vitro fertilization (IVF). MTT assay was used to measure the optimum concentration of CTX and S1P acts on human granulosa cells. Granulosa cells were added with pertussis toxin (PTX), the PI3K inhibitor LY294002. Western blot analysis was used to analyze the signaling pathway of proteins and cell apoptosis. We found that S1P (10 mm) statistically significantly decreased granulosa cell apoptosis after cyclophosphamide (CTX) treatment. The decreased cell apoptosis induced by S1P was abolished after treatment with LY294002, PI3K inhibitor. CONCLUSIONS: Treatment with S1P can inhibit the CTX-induced granulosa cell apoptosis. The S1P protective effect is mediated by activating the PI3K/Akt pathway.

Associations of parathyroid hormone levels and mineral parameters with heart rate variability in patients with end-stage renal disease.

PURPOSE: Parathormone (PTH) is a very potent uraemic toxin, which affects calcium/phosphate homeostasis in patients with end-stage renal disease (ESRD). It also plays the role in uraemic autonomic neuropathy. The aim of the study was to investigate the relationship between elevated PTH levels and cardiac autonomic neuropathy assessed by frequency-domain measures of heart rate variability. METHODS: 24-h ECG was performed in 106 ESRD patients and 65 healthy controls. Very-low-frequency (VLF), low-frequency (LF) and high-frequency (HF) bands were computed. LF/HF ratio was calculated. RESULTS: We found that most heart rate variability indices were lower in ESRD patients than in healthy controls. Variables including demographics (age, sex, body mass index, dialysis vintage, systolic pressure, and diastolic pressure), laboratory values (Hb, Hct, glucose, Alb, and triglyceride), and bone metabolism panel (Ca, P, ALP, and iPTH) were selected as independent variables in the multivariable models. In multivariate analysis, serum intact PTH (iPTH) was correlated with mean normal-to-normal R-R intervals, mean heart rate, and VLF, serum calcium was correlated with standard deviation of 5-min average of normal R-R intervals (SDANN), and serum phosphorus was correlated with VLF and LF/HF. Serum iPTH was independently correlated with mean normal-to-normal R-R intervals (NN), mean HR, and VLF. Serum Ca was independently correlated with SDANN, and serum P was independently correlated with VLF and LF/HF. The results remained significant after the adjustment for iPTH. CONCLUSIONS: In conclusion, high PTH levels and disorders of mineral metabolism are associated with decreased heart rate variability in ESRD patients.

Induction of differentiation of human embryonic stem cells into functional hair-cell-like cells in the absence of stromal cells.

Sensorineural hearing loss and vestibular dysfunction have become the most common forms of sensory defects. Stem cell-based therapeutic strategies for curing hearing loss are being developed. Several attempts to develop hair cells by using chicken utricle stromal cells as feeder cells have resulted in phenotypic conversion of stem cells into inner ear hair-cell-like cells. Here, we induced the differentiation of human embryonic stem cells (hESCs) into otic epithelial progenitors (OEPs), and further induced the differentiation of OEPs into hair-cell-like cells using different substrates. Our results showed that OEPs cultured on the chicken utricle stromal cells with the induction medium could differentiate into hair-cell-like cells with stereociliary bundles. Co-culture with stromal cells, however, may be problematic for subsequent examination of the induced hair-cell-like cells. In order to avoid the interference from stromal cells, we cultured OEPs on laminin with different induction media and examined the effects of the induction medium on the differentiation potentials of OEPs into hair-cell-like cells. The results revealed that the culture of OEPs on laminin with the conditioned medium from chicken utricle stromal cells supplemented with EGF and all-trans retinoic acid (RA) could promote the organization of cells into epithelial clusters displaying hair-cell-like cells with stereociliary bundles. These cells also displayed the expected electrophysiological properties.