GlnR activated transcription of nitrogen metabolic pathway genes facilitates biofilm formation by mycobacterium abscessus.

OBJECTIVES: Nitrogen is indispensable for the synthesis of biomacromolecules. The correlation between nitrogen metabolism and Mycobacterium abscessus (M. abscessus) biofilm formation is unclear. This study constructed global nitrogen regulator gene GlnR (Mab_0744) knockout (ΔglnR) and complementation (ΔglnR::glnR) M. abscessus strains. METHODS: Global nitrogen regulator gene glnR (Mab_0744) knockout (ΔglnR) and complementation (ΔglnR::glnR) M. abscessus strains were constructed. Sauton's medium was used to culture M. abscessus pellicle biofilm. To test the antibiotic susceptibility of pellicle biofilm, clarithromycin, amikacin, cefoxitin or imipenem was added to the medium under biofilms after 14 days of incubation. RT-qPCR and ChIP-qPCR were performed to analyse the transcriptional regulatory function of GlnR. RESULTS: GlnR knockout decreased the growth rate of planktonic cells, reduced biofilm mass and wrinkle formation, and diminished the resistance of biofilms to antibiotics. However, the susceptibility of planktonic cells to antibiotics was not changed by glnR knockout. The growth rate of planktonic ΔglnR cells was accelerated by adding nitrogen sources to the medium; the addition of glutamine or sodium glutamate rescued ΔglnR biofilm morphology and resistance to amikacin, cefoxitin, clarithromycin and imipenem. GlnR bound the promoter region and activated the transcription of eight nitrogen metabolic pathway genes (i.e. glnA, amt, ansP, nirB, nirD, glnD, glnK and narK3), which are closely related to glutamine/glutamate biosynthesis and, thus, regulate biofilm formation. CONCLUSION: This study provides insights into the mechanisms of M. abscessus biofilm formation and its resistance to antibiotics.

Prognosis of early-stage lung adenocarcinoma in young patients.

Lung adenocarcinoma (LUAD) is a familiar lung cancer with a poor prognosis. This study was meant to determine whether there are differences in survival between younger and older patients with early-stage LUAD because of the rise in the incidence of LUAD in young individuals over the previous few decades. We analysed the clinical, therapeutic and prognostic features of a cohort (2012-2013) of 831 consecutive patients with stage I/II LUAD who underwent curative surgical resection at Shanghai Pulmonary Hospital. Propensity score matching (PSM) was performed for age, sex, tumour size, tumour stage and therapy in a 2:1 ratio between the two groups without taking gender, illness stage at operation or decisive treatment into account. Following PSM analysis to create a 2:1 match for comparison, the final survival study included 163 patients with early-stage LUAD <50 years and 326 patients ≥50 years. Surprisingly, younger patients were overwhelmingly female (65.6%) and never smokers (85.9%). There were no statistical differences between the two groups in terms of the overall survival rate (P = 0.067) or time to advancement (P = 0.76). In conclusion, no significant differences stood out between older and younger patients with stage I/II LUAD regarding overall and disease-free survival rates. Younger patients with early-stage LUAD were more likely to be female and never smokers, which suggests that risk factors other than active smoking may be responsible for lung carcinogenesis in these patients.

Heat production and volatile biosynthesis are linked via alternative respiration in Magnolia denudata during floral thermogenesis.

Floral thermogenesis is coupled with odor emission in known thermogenic plants. It is widely accepted that elevation in floral temperature can help release of volatile organic compounds (VOCs). However, no information is available about whether floral thermogenesis is associated with VOC biosynthesis. Here, we used RNA-Sequencing (RNA-Seq) to draw a gene expression atlas of floral thermogenesis in Magnolia denudata and captured an upregulation of Alternative Oxidase (AOX) during floral thermogenesis. Western blot analyses also suggested upregulation of AOX during floral thermogenesis. Moreover, oxygen consumption analyses revealed increased activity of the AOX respiration pathway during floral thermogenesis. Using HPLC analyses, we further found that increased AOX respiration substantially promoted production of citric acid by 1.35 folds, which provided fundamental metabolite skeletons for biosynthesis of VOCs. RNA-Seq also showed upregulation of genes regulating lignin catabolism, which was in agreement with in situ Raman chemical imaging of lignin. Taken together, our results suggest the central role of AOX by coupling heat production and VOC biosynthesis in floral thermogenesis of M. denudata.

Visual feedback therapy for restoration of upper limb function of stroke patients.

OBJECTIVE: To investigate the effects of mirror neuron theory-based visual feedback therapy (VFT) on restoration of upper limb function of stroke patients and motor-related cortical function using functional magnetic resonance imaging (fMRI). METHODS: Hemiplegic stroke patients were randomly divided into two groups: a VFT group and a control (CTL) group. Sixteen patients in the VFT group received conventional rehabilitation (CR) and VFT for 8 weeks, while 15 patients in the CTL group received only CR. The Barthel Index (BI) was used to assess the activities of daily living at baseline and the 8th week of the recovery training period. The Fugl-Meyer assessment (FMA) scale, somatosensory evoked potential (SEP), and fMRI were used to evaluate the recovery effect of the training therapies. The latencies and amplitudes of N9 and N20 were measured. Before recovery training, fMRI was performed for all patients in the VFT and CTL groups. In addition, 17 patients (9 in the VFT group and 8 in the CTL group) underwent fMRI for follow-up 2 months after treatment. Qualitative data were analyzed using the χ 2 test. The independent sample t-test was used to compare normally distributed data among different groups, the paired sample t-test was used to compare data between groups, and the non-parametric test was used to comparing data without normal distribution among groups. RESULTS: There were no significant differences between the VFT and CTL group in all indexes. However, after 8 weeks of recovery training, these indexes were all significantly improved (P < 0.05). As compared with the CTL group, the FMA scores, BI, and N9/N20 latencies and amplitudes of SEP in the VFT group were significantly improved (P < 0.05). Two months after recovery training, fMRI showed that the degree of activation of the bilateral central anterior gyrus, parietal lobe, and auxiliary motor areas was significantly higher in the VFT group than the CTL group (P < 0.05). CONCLUSIONS: VFT based on mirror neuron theory is an effective approach to improve upper extremity motor function and daily activity performance of stroke patients. The therapeutic mechanism promotes motor relearning by activating the mirror neuron system and motor cortex. SEP amplitudes increased only for patients who participated in visual feedback. VFT promotes sensory-motor plasticity and behavioral changes in both the motor and sensory domains.