Insertion sequence transposition activates antimycobacteriophage immunity through an lsr2-silenced lipid metabolism gene island.

Insertion sequences (ISs) exist widely in bacterial genomes, but their roles in the evolution of bacterial antiphage defense remain to be clarified. Here, we report that, under the pressure of phage infection, the IS1096 transposition of Mycobacterium smegmatis into the lsr2 gene can occur at high frequencies, which endows the mutant mycobacterium with a broad-spectrum antiphage ability. Lsr2 functions as a negative regulator and directly silences expression of a gene island composed of 11 lipid metabolism-related genes. The complete or partial loss of the gene island leads to a significant decrease of bacteriophage adsorption to the mycobacterium, thus defending against phage infection. Strikingly, a phage that has evolved mutations in two tail-filament genes can re-escape from the lsr2 inactivation-triggered host defense. This study uncovered a new signaling pathway for activating antimycobacteriophage immunity by IS transposition and provided insight into the natural evolution of bacterial antiphage defense.

Simultaneous Detection of Ascorbic Acid, Dopamine, and Uric Acid Using a Novel Electrochemical Sensor Based on Palladium Nanoparticles/Reduced Graphene Oxide Nanocomposite.

A fresh strategy based on two-step electrochemical reduction for the fabrication of palladium nanoparticles/reduced oxide nanocomposite-modified glass carbon electrode (PdNPs/rGO/GCE) was established in this study. Field emission scanning electron microscopy (FESEM) images showed that spherical PdNPs were evenly distributed on the surface of rGO-modified electrode (rGO/GCE), and the introduction of PdNPs has no effect on the morphology of rGO. Electrochemical impedance spectroscopy (EIS) studies revealed that the conductivity of PdNPs/rGO/GCE was higher than that of rGO/GCE and bare GCE. The electrochemical performances of PdNPs/rGO/GCE sensor were investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and chronoamperometry using ascorbic acid (AA), dopamine (DA), and uric acid (UA) as analytes. At the optimized conditions, wide linear ranges of 0.5-3.5 mM (R 2 = 0.99), 3-15 µM (R 2 = 0.99) and 15-42 µM (R 2 = 0.99), and 0.3-1.4 mM (R 2 = 0.99) towards AA, DA, and UA in ternary mixture were observed, respectively. In addition to superior anti-interference capability, fast response (≤5 s), excellent reproducibility, and good long-term stability were also given by this sensor. These results suggested that PdNPs/rGO/GCE is promising for the simultaneous detection of AA, DA, and UA in practical application.

A preliminary study on the relationship between circulating tumor cells count and clinical features in patients with non-small cell lung cancer.

BACKGROUND: To evaluate the clinical value of circulating tumor cells (CTC) count in peripheral venous blood of patients with non-small cell lung carcinoma (NSCLC). METHODS: A total of 50 NSCLC patients who were diagnosed in Wuxi No. 2 People's Hospital from January 2013 to December 2013 were selected as the NSCLC group, 35 patients with lung benign tumor as the benign group, and 28 healthy subjects as the normal control group. Venous blood samples (3 mL) were collected in all subjects for counting the CTC, and a result of ≥8.7 was judged to be positive. The relationships between the positive rate of CTC and the age, sex, pathological type, and clinical stage of NSCLC were analyzed. RESULTS: CTC count was significantly higher in NSCLC group than in benign group and normal control group. In NSCLC patients, CTC count was not significantly correlated with sex, age, or the pathological type (P>0.05) but was closely related to clinical stage (P<0.01). Among NSCLC patients, CTC count significantly increased along with tumor progression. CONCLUSIONS: CTC count shows certain correlation with the clinical features of NSCLC and thus can, to certain extent, reflect the status of the disease.