Detection of RAS gene mutation and its clinical significance in children with acute lymphoblastic leukemia. / å„¿ç«¥æ€¥æ€§æ·‹å·´ç»†èƒžç™½è¡€ç— ä¸­RASåŸºå› çªå˜çš„æ£€æµ‹åŠå ¶ä¸´åºŠæ„ä¹‰.

OBJECTIVES: To investigate the mutation rate of the RAS gene and its clinical significance in children with acute lymphoblastic leukemia. METHODS: A retrospective analysis was performed on the medical data of 120 children with newly diagnosed acute lymphoblastic leukemia, who were admitted to the Third Affiliated Hospital of Zhengzhou University from January 2015 to January 2020 and underwent next-generation sequencing. The clinical and molecular features were analyzed. The impact of RAS gene mutation on the overall survival rate was evaluated in these children. RESULTS: Among the 120 children, 35 (29.2%) had RAS gene mutation, 30 (25.0%) had KRAS gene mutation, and 5 (4.2%) had both NRAS and KRAS gene mutations. All NRAS mutations and 71% (25/35) of KRAS mutations were located at the 12th and 13th codons. RAS gene mutation was detected in 35 (33.3%) out of 105 children with B-lineage acute lymphoblastic leukemia, but it was not detected in those with acute T lymphocyte leukemia. Of all the children, 11 (9.2%) were lost to follow-up, and among the 109 children followed up, 16 (14.7%) died. The children with RAS gene mutation had a significantly lower 2-year overall survival rate than those without RAS gene mutation (P<0.05). The prognosis of children with RAS gene mutation combined with WT1 overexpression and WBC>50×109/L at diagnosis was worse (P<0.05). CONCLUSIONS: RAS gene mutation is commonly observed in children with B-lineage acute lymphoblastic leukemia and may have an adverse effect on prognosis.

Ruania rhizosphaerae sp. nov., a novel actinobacterium isolated from rhizosphere of Suaeda aralocaspica.

A Gram-stain-positive, non-motile and short rod-shaped actinobacterium, designated strain LNNU 22110T, was isolated from the rhizosphere soil of the halophyte Suaeda aralocaspica (Bunge) Freitag and Schütze, which collected in Xinjiang, north-west China. Growth occurred at 10-45 °C, pH 6.0-10.0 and in the presence of 0-11 % NaCl (w/v). Based on the results of 16S rRNA gene sequence phylogenetic analyses, strain LNNU 22110T belonged to the genus Ruania and had 97.5 and 95.5 % sequence similarity to Ruania alba KCTC 19413T and Ruania albidiflava CGMCC 4.3142T, respectively. The digital DNA-DNA hybridization relatedness values between strain LNNU 22110T and R. alba KCTC 19413T and R. albidiflava CGMCC 4.3142T were 23.2 and 19.9 %, respectively. The highest average nucleotide identity value between strain LNNU 22110T and its closest related strain (R. alba KCTC 19413T) was 80.2 %, much lower than the species delineation threshold of 95-96 %. The genome of strain LNNU 22110T was 4.4 Mb, with a genomic DNA G+C content of 68.4 mol%. The diagnostic diamino acids in the peptidoglycan layer of strain LNNU 22110T were lysine, alanine, glycine, glutamic acid and aspartic acid. The predominant menaquinone was MK-8(H4). The major fatty acid (>10 %) was anteiso-C15 : 0. The polar lipid profile of strain LNNU 22110T included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, diacylated phosphatidyl dimannoside, one unidentified glycolipid and two unidentified phospholipids. According to the phenotypic, phylogenetic and chemotaxonomic results, strain LNNU 22110T is considered to represent a novel species of the genus Ruania, for which the name Ruania rhizosphaerae sp. nov. is proposed. The type strain is LNNU 22110T (=KCTC 39807T=CGMCC 1.17105T).