Natural variation in a molybdate transporter controls grain molybdenum concentration in rice.

Molybdenum (Mo) is an essential micronutrient for most living organisms, including humans. Cereals such as rice (Oryza sativa) are the major dietary source of Mo. However, little is known about the genetic basis of the variation in Mo content in rice grain. We mapped a quantitative trait locus (QTL) qGMo8 that controls Mo accumulation in rice grain by using a recombinant inbred line population and a backcross introgression line population. We identified a molybdate transporter, OsMOT1;1, as the causal gene for this QTL. OsMOT1;1 exhibits transport activity for molybdate, but not sulfate, when heterogeneously expressed in yeast cells. OsMOT1;1 is mainly expressed in roots and is involved in the uptake and translocation of molybdate under molybdate-limited condition. Knockdown of OsMOT1;1 results in less Mo being translocated to shoots, lower Mo concentration in grains and higher sensitivity to Mo deficiency. We reveal that the natural variation of Mo concentration in rice grains is attributed to the variable expression of OsMOT1;1 due to sequence variation in its promoter. Identification of natural allelic variation in OsMOT1;1 may facilitate the development of rice varieties with Mo-enriched grain for dietary needs and improve Mo nutrition of rice on Mo-deficient soils.

Value of combined detection of AFU and TCH in differential diagnosis between malignant and non-tuberculous benign ascites.

The purpose of this study was to accurately evaluate the diagnostic efficacy of combined detection of ascitic fluid alpha-L-fucosidase (AFU) and cholesterol (TCH) compared with that of their individual detection. We assayed ascitic AFU activity by colorimetry and TCH level by CHOD-PAP method simultaneously in all 213 cases. Then, we assessed the value of combined detection of AFU and TCH activities with receiver operating characteristic curve (ROC curve), including diagnostic sensitivity, specificity, diagnostic accuracy, positive predict value(PV+), negative predict value(PV-) to see whether these two ascitic fluid biochemical examinations might help in differential diagnosis between malignant and non-tuberculous benign ascites. The mean values of AFU and TCH in malignant group [(164.96 ± 87.72) µmol/lh and (1.65 ± 1.00) mmol/l, respectively] were significantly higher than those in non-tuberculous benign group [(104.02 ± 62.08) µmol/lh and (0.69 ± 0.58) mmol/l, respectively] (P < 0.01). The optimal cutoff value of 101.95 µmol/lh for ascitic AFU and 1.04 mmol/l for ascitic TCH resulted in a diagnostic sensitivity of 82.3% and 70.8%, specificity of 63.2 and 83.8%, accuracy of 72.8 and 77.9%, PV+ of 65.3 and 78.2%, PV- of 83.1 and 77.8%, respectively. Combined detection of the two markers, the sensitivity, specificity, accuracy, PV+ and PV- were 86.5, 85.5, 85.9, 83.0, and 88.5%, respectively. Through comparison by Pearson Chi-square, the combined detection of AFU and TCH produced better diagnostic accuracy (85.9%) compared with the individual detection (P < 0.05). The combined detection of AFU and TCH produced better diagnostic accuracy in comparison with their individual detection, which is helpful to differential diagnosis between malignant and non-tuberculous benign ascites that may be relatively ideal markers to fit for clinical application in local hospitals.

Temporal and parental-specific expression of imprinted genes in a newly derived Chinese human embryonic stem cell line and embryoid bodies.

Although the study of imprinted genes in human development is very important, little is known about their expression and regulation in the early differentiation of human tissues due to lack of an appropriate model. In this study, a Chinese human embryonic stem (hES) cell line, SHhES1, was derived and fully characterized. Expression profiles of human imprinted genes were determined by Affymetrix Oligo micro-array in undifferentiated SHhES1 cells and SHhES1-derived embryoid bodies (EBs) at day 3, 8, 13 and 18. Thirty-two known human imprinted genes were detected in undifferentiated ES cells. Significantly, differential expression was found in nine genes at different stages of EB formation. Expression profile changes were confirmed by quantitative real-time reverse transcriptase-polymerase chain reaction in SHhES1 cells as well as in another independently derived hES cell line, HUES-7. In addition, the monoallelic expressions of four imprinted genes were examined in three different passages of undifferentiated ES cells and EBs of both hES cell lines. The monoallelic expressions of imprinted genes, H19, PEG10, NDNL1 and KCNQ1 were maintained in both undifferentiated hES cells and derived EBs. More importantly, with the availability of maternal peripheral blood lymphocyte sample, we demonstrated that the maternal expression of KCNQ1 and the paternal expression of NDNL1 and PEG10 were maintained in SHhES1 cells. These data provide the first demonstration that the parental-specific expression of imprinted genes is stable in EBs after extensive differentiation, also indicating that in vitro fertilization protocol does not disrupt the parental monoallelic expression of the imprinted genes examined.