Pleiotropic drug resistance(PDR) transporters belonging to the ABCG subfamily of ATP-binding cassette(ABC)transporters are identified only in fungi and plants. Members of this family are expressed in plants in response to various biotic and abiotic stresses and transport a diverse array of molecules across membranes. Although their detailed transport mechanism is largely unknown, they play important roles in detoxification processes, preventing water loss, transport of phytohormones,and secondary metabolites. This review provides insights into transport mechanisms of plant PDR transporters, their expression profiles, and multitude functions in plants.
Mohammed NuruzzamanRu ZhangHong-Zhe CaoZhi-Yong Luo
Objective Obesity is becoming a worldwide health problem. The genome wide association(GWA) study particularly for body mass index(BMI) has not been successfully conducted in the Chinese. In order to identify novel genes for BMI variation in the Chinese, an initial GWA study and a follow up replication study were performed. Methods Affymetrix 500K SNPs were genotyped for initial GWA of 597 Northern Chinese. After quality control, 281 533 SNPs were included in the association analysis. Three SNPs were genotyped in a Southern Chinese replication sample containing 2 955 Chinese Han subjects. Association analyses were performed by Plink software. Results Eight SNPs were significantly associated with BMI variation after false discovery rate(FDR) correction(P=5.45×10-7-7.26×10-6, FDR q=0.033-0.048). Two adjacent SNPs(rs4432245 & rs711906) in the eukaryotic translation initiation factor 2 alpha kinase 4(EIF2AK4) gene were significantly associated with BMI(P=6.38×10-6 & 4.39×10-6, FDR q=0.048). In the follow-up replication study, we confirmed the associations between BMI and rs4432245, rs711906 in the EIF2AKE gene(P=0.03 & 0.01, respectively). Conclusion Our study suggests novel mechanisms for BMI, where EIF2AK4 has exerted a profound effect on the synthesis and storage of triglycerides and may impact on overall energy homeostasis associated with obesity. The minor allele frequencies for the two SNPs in the EIF2AK4 gene have marked ethnic differences between Caucasians and the Chinese. The association of the EIF2AK4 gene with BMI is suggested to be ‘ethnic specific' in the Chinese.
YANG FangCHEN Xiang DingTAN Li JunSHEN JieLI Ding YouZHANG FangSHA Bao YongDENG Hong Wen
Objective To identify and determine the optimal method to screening for fetal Down's syndrome (DS). Methods Three large cohorts with 17 118, 39 903, 16 646 subjects were enrolled for the first trimester double marker (pregnancy-associated plasma protein A and free β-human chorionic gonadotropin) screening (FTDMS), second trimester double marker (α-fetoprotein and free β-human chorionic gonadotropin) screening (STDMS), and second trimester triple marker (α-fetoprotein, free β-human chorionic gonadotropin and unconjugated estriol 3) screening (STTMS), respectively. The sensitivity, specificity, false positive rate (FPR), false negative rate (FNR) and the areas under ROC curves (AUCs) were estimated in order to determine the optimal screening method in women under or above 35 years old. Results For women under 35 years old, STTMS was the best method with a detection rate of 68.8% and FPR of 4.3% followed by the STDMS with a detection rate (sensitivity) of 66.7% and FPR of 4.9%. The FTDMS had a lower detection rate of 61.1% and FPR of 6.3%. For women above 35 years old, the detection rate of all the methods was similar, but STTMS method had a lowest FPR of 15.9%. For women under 35 years old AUCs were 0.77 (95% CI, 0.64 to 0.91), 0.81 (95% CI, 0.71 to 0.91), and 0.82 (95% CI, 0.69 to 0.96) for FTDMS, STDMS, and STTMS methods, respectively; for those above 35 years old, AUCs were 0.70 (95% CI, 0.56 to 0.83), 0.70 (95% CI, 0.59 to 0.82), 0.78 (95% CI, 0.58 to 0.97) for FTDMS, STDMS and STTMS , respectively. Conclusion Findings from our study revealed that STDMS is optimal for the detection of fetal DS in pregnant women aged under 35. For individual women, if economic condition permits, STTMS is the best choice, while for women aged above 35, STTMS is the best choice in this regard.
