Soil nutrient budgets following projected corn stover harvest for biofuel production in the conterminous United States

Increasing demand for food and biofuel feedstocks may substantially affect soil nutrient budgets, especially in the United States where there is great potential for corn (Zea mays L) stover as a biofuel feedstock. This study was designed to evaluate impacts of projected stover harvest scenarios on budgets of soil nitrogen (N), phosphorus (P), and potassium (K) currently and in the future across the conterminous United States. The required and removed N, P, and K amounts under each scenario were estimated on the basis of both their average contents in grain and stover and from an empirical model. Our analyses indicate a small depletion of soil N (?4 ± 35 kg ha^?1) and K (?6 ± 36 kg ha^?1) and a moderate surplus of P (37 ± 21 kg ha^?1) currently on the national average, but with a noticeable variation from state to state. After harvesting both grain and projected stover, the deficits of soil N, P, and K were estimated at 114–127, 26–27, and 36–53 kg ha^?1 yr^?1, respectively, in 2006–2010; 131–173, 29–32, and 41–96 kg ha^?1 yr^?1, respectively, in 2020; and 161–207, 35–39, and 51–111 kg ha^?1 yr^?1, respectively, in 2050. This study indicates that the harvestable stover amount derived from the minimum stover requirement for maintaining soil organic carbon level scenarios under current fertilization rates can be sustainable for soil nutrient supply and corn production at present, but the deficit of P and K at the national scale would become larger in the future.     

MicroRNA-486 as a Biomarker for Early Diagnosis and Recurrence of Non-Small Cell Lung Cancer

Background

Non-small cell lung cancer (NSCLC) is a leading cause of cancer death worldwide. Early diagnosis is essential for improvements of prognosis and survival of the patients. Currently, there is no effective biomarker available in clinical settings for early detection of lung cancer. Altered expressions in many cancer types including NSCLC and stable existence in plasma make microRNAs (miRNAs) a group of potentially useful biomarkers for clinical assessments of patients with NSCLC.

Objectives

To evaluate the potential values of miRNAs as blood-based biomarkers for early diagnosis and prognosis in NSCLC patients.

Methods

Peripheral blood samples from healthy volunteers and early-staged NSCLC patients before and after surgery were collected, and plasma was separated. Expression of ten miRNAs in the plasma and tumor sections of the patients was detected by quantitative real-time polymerase chain reaction.

Results

MiRNA (miR)-486 and miR-150 were found to significantly distinguish lung cancer patients from healthy volunteers. Area under curve of miR-486 and miR-150 were 0.926 (sensitivity, 0.909; specificity, 0.818) and 0.752 (sensitivity, 0.818; specificity, 0.818), respectively. In response to therapy, patients with down-regulated miR-486 expression showed prolonged recurrence-free survival than those with un-reduced miR-486 expression (median, unreached vs. 19 months; hazard ratio, 0.1053; 95% confidence interval, 0.01045 to 1.060; P=0.056).

Conclusions

The results suggest that miR-486 and miR-150 could be potential blood-based biomarkers for early diagnosis of NSCLC. Monitoring change of miR-486 expression in plasma might be an effective and non-invasive method for recurrence prediction of early-staged NSCLC patients.     

Low genetic variation detected within the widespread mangrove species Nypa fruticans (Palmae) from Southeast Asia

Genetic diversity within and among six natural populations of Nypa fruticans from China, Vietnam, and Thailand was assessed using SSR and ISSR analysis. Our results showed an extremely low level of genetic diversity of N. fruticans (at the species level, P = 11.76% and 2.88%, He = 0.0279 and 0.0113, I = 0.0470 and 0.0167 by SSRs and ISSRs, respectively) across a total of 183 individuals. No genetic variation was detected within any population except for the Thailand population by SSRs (P = 11.76%, He = 0.0417; I = 0.0622). The bottlenecks during glacial epochs, founder effects, and propagation pattern may be responsible for the extremely low level of genetic diversity of N. fruticans.     

Transgene flow to hybrid rice and its male-sterile lines

Gene flow from genetically modified (GM) crops to the same species or wild relatives is a major concern in risk assessment. Transgenic rice with insect and/or disease resistance, herbicide, salt and/or drought tolerance and improved quality has been successfully developed. However, data on rice gene flow from environmental risk assessment studies are currently insufficient for the large-scale commercialization of GM rice. We have provided data on the gene flow frequency at 17 distances between a GM japonica line containing the bar gene as a pollen donor and two indica hybrid rice varieties and four male-sterile (ms) lines. The GM line was planted in a 640m² in an isolated experimental plot (2.4 ha), which simulates actual conditions of rice production with pollen competition. Results showed that: (1) under parallel plantation at the 0-m zone, the transgene flow frequency to the ms lines ranged from 3.145 to 36.116% and was significantly higher than that to hybrid rice cultivars (0.037–0.045%). (2) Gene flow frequency decreased as the distance increased, with a sharp cutoff point at about 1–2 m; (3) The maximum distance of transgene flow was 30–40 m to rice cultivars and 40–150 m to ms lines. We believe that these data will be useful for the risk assessment and management of transgenic rice lines, especially in Asia where 90% of world's rice is produced and hybrid rice varieties are extensively used. Shirong Jia, Feng Wang and Lei Shi contributed equally to this investigation.     

PIK3CA hotspot mutations p. H1047R and p. H1047L sensitize breast cancer cells to thymoquinone treatment by regulating the PI3K/Akt1 pathway

Background

Nigella sativa (N. sativa) exhibits anti-inflammatory, antioxidant, antidiabetic, antimetastatic and antinociceptive effects and has been used to treat dozens of diseases. Thymoquinone (TQ) is an important and active component isolated from N. sativa seeds. Inhibition of cancer-associated activating PIK3CA mutations is a new prospective targeted therapy in personalized metastatic breast cancer (MBC). TQ is reported to be an effective inhibitor of the PI3K/Akt1 pathway in MBC. This study aimed to evaluate the in vitro antitumor effect of TQ in the context of two PIK3CA hotspot mutations, p. H1047R and p. H1047L.

Methods and results

Molecular dynamics, free energy landscapes and principal component analyses were also used to survey the mechanistic effects of the p. H1047R and p. H1047L mutations on the PI3K/Akt1 pathway. Our findings clearly confirmed that the p. H1047R and p. H1047L mutants could reduce the inhibitory effect of ΔNp63α on the kinase domain of PIK3CA, resulting in increased activity of PI3K downstream signals. Structurally, the partial disruption of the interaction between the ΔNp63α DNA binding domain and the PIK3CA kinase domain at residues 114–359 and 797–1068 destabilizes the conformation of the activation loop and modifies the PIK3CA/ΔNp63α complex. Alongside these structural changes, we found that TQ treatment resulted in high PI3K/Akt1 pathway inhibition in p. H1047R and p. H1047L-expressing cells versus wild-type cells.

Conclusions

These two PIK3CA hotspot mutations therefore not only contribute to tumor progression in patients with MBC but may also serve as targets for the development of novel small molecule therapeutic strategies.