Search

The nitrogen (N) use efficiency (NUE) in the roots of seedlings is beneficial for increasing crop yield. Creating marker-assisted selection for wheat root traits can assist wheat breeders in choosing robust roots to maximize nutrient uptake. Exploring and identifying the effect of different N supply conditions on root system architecture (RSA) is of great significance for breeding N efficient wheat varieties. In this study, a total of 243 wheat varieties native to the Yellow and Huai Valley regions of China were utilized for genome-wide association studies (GWAS). Furthermore, a recombinant inbred line (RIL) population of 123 lines derived from the cross between Avocet and Chilero was utilized for linkage examination. A hydroponic seedling experiment using a 96-well tray was conducted in the lab with two treatments: normal N (NN) and low N (LN). Five RSA traits, including the relative number of root tips (RNRT), relative total root length (RTRL), relative total root surface area (RTRS), relative total root volume (RTRV), and relative average root diameter (RARD), were investigated. GWAS and linkage analysis were performed by integrating data from the wheat 660 k single nucleotide polymorphism (SNP) chip and diversity arrays technology (DArT) to identify genetic loci associated with RSA. The results showed that, based on the ratio of RSA-related traits under two N supply conditions, a total of 497 SNP markers, which are significantly associated with RSA-related traits, were detected at 148 genetic loci by GWAS. A total of 10 QTL loci related to RSA were discovered and identified by linkage mapping. Combining two gene localization methods, three colocalized intervals were found: AX-95160997/QRtrl.haust-3D, AX-109592379/QRnrt.haust-5A, and AX-110924288/QRtrl.haust-7D/QRtrs.haust-7D. According to the physical location of the colocalization of these two sites, between 39.61 and 43.74 Mb, 649.97 and 661.55 Mb, and 592.44 and 605.36 Mb are called qRtrl-3D, qRnrt-5A, and qRtrl-7D. This study has the potential to enhance the effectiveness of selecting root traits in wheat breeding programs, offering valuable insights into the genetic underpinnings of NUE in wheat. These results could help in breeding wheat varieties with higher NUE by implementing focused breeding strategies. [ABSTRACT FROM AUTHOR]

Elderly hemodialysis (HD) patients have a high risk of death. The effect of different types of HD membranes on survival is still controversial. The purpose of this study was to determine the relationship between the use of low-flux or high-flux membranes and all-cause and cardiovascular mortality in elderly hemodialysis patients. This was a retrospective clinical study involving maintenance hemodialysis patients which were categorized into low-flux and high-flux groups according to the dialyzer they were using. Propensity score matching was used to balance the baseline data of the two groups. Survival rates were compared between the two groups, and the risk factors for death were analyzed by multivariate Cox regression. Kaplan–Meier survival analysis revealed no significant difference in all-cause mortality between the low-flux group and the high-flux group (log-rank test, p = 0.559). Cardiovascular mortality was significantly greater in the low-flux group than in the high-flux group (log-rank test, p = 0.049). After adjustment through three different multivariate models, we detected no significant difference in all-cause mortality. Patients in the high-flux group had a lower risk of cardiovascular death than did those in the low-flux group (HR = 0.79, 95% CI, 0.54–1.16, p = 0.222; HR = 0.58, 95% CI, 0.37–0.91, p = 0.019). High-flux hemodialysis was associated with a lower relative risk of cardiovascular mortality in elderly MHD patients. High-flux hemodialysis did not improve all-cause mortality rate. Differences in urea distribution volume, blood flow, and systemic differences in solute clearance by dialyzers were not further analyzed, which are the limitations of this study. [ABSTRACT FROM AUTHOR]

Abdominal aortic calcification (AAC) assessed by using standard lateral lumbar radiographs can be graded, and composite summary scores (range, 0–24) have been shown to be highly predictive of subsequent cardiovascular morbidity and mortality in hemodialysis (HD) patients. However, few studies have sought to determine the optimal AAC score cutoff values for the prediction of mortality among HD patients. This retrospective cohort study included 408 hemodialysis patients. AAC severity was quantified by the AAC score, which was measured by lateral lumbar radiography with complete follow-up data from January 2015 to December 2021. We used receiver operating characteristic (ROC) analysis to find the cutoff AAC value for the prediction of mortality. The Kaplan–Meier method was used to analyze all-cause and cardiovascular mortality. The cutoff calcification score for the prediction of mortality was 4.5 (sensitivity, 67.3%; specificity, 70.4%). The patients with AAC scores above 4.5 had significantly higher all-cause (log-rank p < 0.001) and cardiovascular (log-rank p < 0.001) mortality rates than those with AAC scores below 4.5. In the multivariate regression analyses, an AAC score above 4.5 was a significant factor associated with all-cause mortality (HR: 2.079, p = 0.002) and cardiovascular mortality (HR: 2.610, p < 0.001). AAC is a reliable aortic calcification marker. HD patients with an AAC score > 4.5 have significantly elevated all-cause and cardiovascular mortality compared with those with an AAC score ≤ 4.5. AAC was a better predictor than cardiac valve calcification for mortality in HD patients. [ABSTRACT FROM AUTHOR]