Mutations in KARS cause early-onset hearing loss and leukoencephalopathy: Potential pathogenic mechanism.

Leukoencephalopathies are a broad class of common neurologic deterioration for which the etiology remains unsolved in many cases. In a Chinese Han family segregated with sensorineural hearing loss and leukoencephalopathy, candidate pathogenic variants were identified by targeted next-generation sequencing of 144 genes associated with deafness and 108 genes with leukoencephalopathy. Novel compound heterozygous mutations p.R477H and p.P505S were identified in KARS, which encodes lysyl-tRNA synthetase (LysRS), as the only candidate causative variants. These two mutations were functionally characterized by enzymatic assays, immunofluorescence, circular dichroism analysis, and gel filtration chromatography. Despite no alteration in the dimer-tetramer oligomerization and cellular distribution by either mutation, the protein structure was notably influenced by the R477H mutation, which subsequently released the protein from the multiple-synthetase complex (MSC). Mutant LysRSs with the R477H and P505S mutations had decreased tRNALys aminoacylation and displayed a cumulative effect when introduced simultaneously. Our studies showed that mutations in KARS lead to a newly defined subtype of leukoencephalopathy associated with sensorineural hearing impairment. The combined effect of reduced aminoacylation and release of LysRS from the MSC likely underlies the pathogenesis of the KARS mutations identified in this study.

A cyanine dye probe for K+ detection based on DNA construction of G-quadruplex.

Potassium ion (K+) plays an important role in the maintenance of cellular biological process for human health. Thus, the detection of K+ is very important. Here, based on the interaction between thiamonomethinecyanine dye and G-quadruplex formation sequence (PW17), K+ detection spectrum was characterized by UV-Vis spectrometry. The single-stranded sequence of PW17 can fold into G-quadruplex in the presence of K+. PW17 can induce a dimer-to-monomer transition of the absorption spectrum of cyanine dyes. This method shows high specificity against some other alkali cations, even at high concentrations of Na+. Further, this detection strategy can realize the detection of K+ in tap water.

Removal of nickel from aqueous solutions by sawdust.

The main parameters influencing Nickel (II) metal sorption on maple sawdust were: initial metal ion concentration, amount of adsorbent, and pH value of solution. The maximum percent metal removal was attained after about 1h. The greatest increase in the rate of adsorption of metal ions on sawdust was observed for pH changes from 2 to 5. An empirical relationship has been obtained to predict the percentage Nickel (II) removal at any time for known values of sorbent and initial sorbate concentration. The experimental results provided evidence for chelation ion exchange as the major adsorption mechanisms for binding metal ions to the sawdust. The adsorbent can be effectively regenerated using 0.1 M strong acid and reused.

Adsorption of chromium from aqueous solutions by maple sawdust.

This paper presents the data for the effect of adsorbent dose, initial sorbate concentration, contact time, and pH on the adsorption of chromium(VI) on maple sawdust. Batch adsorption studies have been carried out. An empirical relationship has been obtained to predict the percentage chromium(VI) removal at any time for known values of sorbent and initial sorbate concentration. Under observed test conditions, the equilibrium adsorption data fits the linear Langmuir and Freundlich isotherms. The experimental result inferred that chelation ion exchange is one of the major adsorption mechanisms for binding metal ions to the maple sawdust.

[Quality control for ABO blood group typing of neonatal umbilical cord blood].

This study was aimed to investigate a quality control method for ABO typing of neonatal umbilical cord blood(UCB). The routine serology method was used to identify the ABO type of UCB samples. These samples with questions were further detected by sequence specific primer PCR (PCR-SSP). The results showed that among total of 76120 UCB samples identified by positive ABO typing, there were 78 samples (1 per thousand) which could not be determined. Of these 78 samples, 30 (56.92%) samples with a weak agglutination reaction were excluded by reverse ABO typing. Out of 260 samples in reverse ABO typing, 148 samples were consistent with positive ABO typing, 112 samples (43.08%) were inconsistent with the positive ABO typing. 58 undetermined samples were detected by PCR-SSP. Out of them the genotyping results of 45 samples confirmed the serological typing, the phenotyping results in 3 cases were inconsistent to that of genotyping. 10 cases showed the unconformity between positive and reverse typing, but the genotyping results were fully consistent with the positive typing. In conclusion, positive typing for red cell antigens combined with PCR-SSP is efficient and sensitive for quality control of ABO typing for neonatal UCB.

[Correlation of HLA-alleles with aplastic anemia].

To investigate the correlation between the HLA genes and pathogenesis of aplastic anemia (AA), polymerase chain reaction with specific sequence primers (PCR-SSP) method was used to HLA typing in 82 patients with AA and 400 normal healthy individuals as control. The results showed that A*2301 (1.84%), B*5501 (4.36%) and DRB1*0901 (23.48%) gene frequency in AA patients were significantly higher than those in controls (relative risk: RR=5.0253, 3.3645, 2.1269, chi2=4.6634, 6.3120, 9.1511 respectively) (p<0.01). In contrast, DRB1*1301 (1.23%) gene frequency was significantly lower in AA than that in controls, RR=0.2257, chi2=6.6629 (p<0.01). It is concluded that A*2301, B*5501 and DRB1*0901 genes may be considered as the risk markers while DRB1*1301 gene as a protective marker of AA.