BackgroundNitrogen (N) is an essential and often limiting nutrient to plant growth and development. Previous studies have shown that the mRNA expressions of numerous genes are regulated by nitrogen supplies; however, little is known about the expressed non-coding elements, for example long non-coding RNAs (lncRNAs) that control the response of maize (Zea mays L.) to nitrogen. LncRNAs are a class of non-coding RNAs larger than 200 bp, which have emerged as key regulators in gene expression.ResultsIn this study, we surveyed the intergenic/intronic lncRNAs in maize B73 leaves at the V7 stage under conditions of N-deficiency and N-sufficiency using ribosomal RNA depletion and ultra-deep total RNA sequencing approaches. By integration with mRNA expression profiles and physiological evaluations, 7245 lncRNAs and 637 nitrogen-responsive lncRNAs were identified that exhibited unique expression patterns. Co-expression network analysis showed that the nitrogen-responsive lncRNAs were enriched mainly in one of the three co-expressed modules. The genes in the enriched module are mainly involved in NADH dehydrogenase activity, oxidative phosphorylation and the nitrogen compounds metabolic process.ConclusionsWe identified a large number of lncRNAs in maize and illustrated their potential regulatory roles in response to N stress. The results lay the foundation for further in-depth understanding of the molecular mechanisms of lncRNAs’ role in response to nitrogen stresses.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-2650-1) contains supplementary material, which is available to authorized users.

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This review aimed to evaluate the efficacy of low-level laser therapy (LLLT) for accelerating tooth movement during orthodontic treatment. An extensive electronic search was conducted by two reviewers. Randomized controlled trials (RCTs) and quasi-RCTs concerning the efficacy of LLLT for accelerating tooth movement during orthodontic treatment were searched in CENTRAL, Medline, PubMed, Embase, China Biology Medicine Disc (CBM), China National Knowledge Infrastructure (CNKI), and Google Scholar. Six RCTs and three quasi-RCTs, involving 211 patients from six countries, were selected from 173 relevant studies. All nine articles were feasible for the systematic review and meta-analysis, five of which were assessed as moderate risk of bias, while the rest were assessed as high risk of bias. The mean difference and the 95 % confidence interval (95 % CI) of accumulative moved distance of teeth were observed among all the researches. The results showed that the LLLT could accelerate orthodontic tooth movement (OTM) in 7 days (mean difference 0.19, 95 % CI [0.02, 0.37], p = 0.03) and 2 months (mean difference 1.08, 95 % CI [0.16, 2.01], p = 0.02). Moreover, a relatively lower energy density (5 and 8 J/cm(2)) was seemingly more effective than 20 and 25 J/cm(2) and even higher ones.

Lung cancer is the leading cause of cancer death in men and women worldwide. Brain metastasis (BMs) of non-small cell lung cancer (NSCLC) is the most important cause of death. This study aimed to explore the association of epidermal growth factor receptor (EGFR) mutations and BMs in NSCLC. We analyzed 50 NSCLC patients with BMs and 50 match-paired NSCLC patients with no brain metastases (NBMs). The EGFR mutation status of primary lesions was detected using the amplification refractory mutation system polymerase chain reaction. The BMs patients had a higher frequency of EGFR mutations than the NBMs patients (52.0 vs. 22.0% respectively, P < 0.001), in both adenocarcinoma (60.5 vs. 30.6%, P = 0.003) and squamous carcinoma (37.5 vs. 0%, P = 0.04). The incidence of BMs in patients with EGFR mutations was higher than in patients with wild-type EGFR (70.3 vs. 38.1%, P = 002). NSCLC patients with BMs had a higher incidence of EGFR mutations and those with mutant EGFR had a higher frequency of BMs. EGFR mutations may promote brain metastasis growth of NSCLC.