Streptomyces zhihengii sp. nov., isolated from rhizospheric soil of Psammosilene tunicoides.

An actinomycete strain, designated YIM T102(T), was isolated from the rhizospheric soil of Psammosilene tunicoides W. C. Wu et C. Y. Wu collected from Lijiang, Yunnan Province, China. The taxonomic position of the new isolate was investigated by a polyphasic approach. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain YIM T102(T) belongs to the genus Streptomyces. Strain YIM T102(T) was most closely related to Streptomyces eurocidicus NRRL B-1676(T) with a pairwise 16S rRNA gene sequence similarity of 98.9 %. However, DNA-DNA relatedness value between strain YIM T102(T) and S. eurocidicus NBRC 13491(T) was found to be 37.8 ± 1.8 %. The menaquinone composition detected for strain YIM T102(T) was MK-9 (H6) and MK-9 (H8), while the major fatty acids were summed feature 4 (38.0 %), anteiso-C15:0 (13.1 %), iso-C16:0 (10.1 %), summed feature 3 (9.8 %) and C16:0 (9.0 %) and iso-C15:0 (5.2 %). The whole-cell hydrolysates contained galactose, glucose, ribose and mannose, along with LL-diaminopimelic acid as the diagnostic diamino acid in the peptidoglycan. The DNA G+C content was 70.7 mol%. Strain YIM T102(T) also exhibited antagonistic activity against Alternaria alternata, Alternaria brassicae and Colletotrichum nicotianae Averna, based on the findings from the comparative analyses of phenotypic and genotypic characteristics; it is proposed that strain YIM T102 represents a novel species of the genus Streptomyces, for which the name Streptomyces zhihengii sp. nov. is proposed. The type strain is YIM T102(T) (=KCTC 39115(T) = DSM 42176(T) = CGMCC 4.7248(T)).

Visual DNA microarray for detection of epidermal growth factor receptor (EGFR) gene mutations.

OBJECTIVE: To develop a gold nanoparticle-based visual DNA microarray for simple and rapid screening of EGFR gene mutations. METHODS: The DNA fragments contain epidermal growth factor receptor (EGFR) exons 18, 19, 20 and 21 were amplified by polymerase chain reaction (PCR) using biotin-modified primers. The amino-modified oligonucleotides were immobilized on glass surface, which were used as the capturing probes to bind the complement biotinylated target DNA. After the PCR product has been hybridized to the immobilized capture probe DNA on the glass slides, the Streptavidin-conjugated gold nanoparticles were introduced to the microarray via specific binding to 5'-end biotin of the PCR products. The hybridization signal on array spots was enhanced and visualized by silver amplification. The EGFR mutation in 286 clinical samples from cancer patients were tested using the gold nanoparticle-based microarray and verified with Sanger DNA sequencing method. RESULTS: A novel visual DNA microarray has been developed to detect EGFR mutations in tumor tissue specimens rapidly; its limit of detection (LOD) is up to 10(-9) mol/L and distinguishes power to detect 5% gene mutation in the mixture samples. CONCLUSION: For its high specificity and sensitivity, simplicity, lower price and higher speed, the present visual mutation detecting technique has potential application in clinical fields.

Dysfunction of the Glymphatic System Might Be Related to Iron Deposition in the Normal Aging Brain.

Objective: The study aims to detect the potential relationship between iron deposition and the function of the glymphatic system in the normal aging brain. Methods: We recruited 213 healthy participants. We evaluated the function of the glymphatic system using the index for diffusivity along the perivascular space (ALPS-index), assessed iron deposition on quantitative susceptibility mapping (QSM), and analyzed their relationship. Results: The mean age of participants was 60.1 ± 7.3, and 107 (50.2%) were female. The mean ALPS-index was 1.4 ± 0.2. The QSM values of the caudate nucleus, putamen, globus pallidus, thalamus, red nucleus, substantia nigra, and dentate nucleus were all related to the ALPS-index (all P < 0.001). Conclusions: The main finding of the current study is that the regional brain iron deposition was related to the function of the glymphatic system. Advances in knowledge: We first evaluated the relationship between deposition of brain iron and the dysfunction of the glymphatic system.