The fluorescent probe based on methyltetrahydroxanthylium skeleton for the detection of hydrazine.

Two probes based on tetrahydroxanthylium unit (probe 1a) and methyltetrahydroxanthylium unit (probe 1b) were designed and synthesized for the detection of hydrazine. Probes 1a-b exhibited turn-on red emission signal and high selectivity toward NH2NH2. The response time of probe 1a to NH2NH2 was more than 60 min, while that of probe 1b was less than 30 min. The detection limits of probes 1a-b were calculated as 210 nM and 110 nM respectively. What's more, the tolerance experiments showed that methyltetrahydroxanthylium unit possessed higher tolerance toward nucleophiles. Moreover, cells imaging experiments demonstrated that probe 1b could detect exogenous NH2NH2 in living HeLa cells.

Adenine-based small molecule fluorescent probe for imaging mitochondrial nucleic acid.

A small molecule fluorescent probe (probe 1) based on adenine-coumarin derivative was designed and synthesized in this paper. Probe 1 exhibited a significant fluorescence-enhancing response to nucleic acids at 495 nm (for DNA) and 487 nm (for RNA). The fluorescence enhancement of probe 1 for DNA and RNA was 5.68 and 9.73 times respectively, the fluorescence quantum yield was changed from 2.5% to 11.7% and 22.5% accordingly. Meanwhile, an excellent linear relationship of fluorescence intensity at 495 nm or 487 nm versus the nucleic acid concentration (1 µM for probe 1, 0-350 µg/mL for DNA and 0-300 µg/mL for RNA) was obtained. Co-staining and nucleic acid digestion experiments showed that probe 1 could selectively image nucleic acids in mitochondria and nucleoli in HeLa cells.

Identification of non-fermenting Gram-negative bacteria of clinical importance by an oligonucleotide array.

Many species of non-fermenting Gram-negative bacilli (non-fermenters) are important opportunistic and nosocomial pathogens. Identification of most species of non-fermenters by phenotypic characteristics can be difficult. In this study, an oligonucleotide array was developed to identify 38 species of clinically relevant non-fermenters. The method consisted of PCR-based amplification of 16S-23S rRNA gene intergenic spacer (ITS) regions using bacterial universal primers, followed by hybridization of the digoxigenin-labelled PCR products with oligonucleotide probes immobilized on a nylon membrane. A total of 398 strains, comprising 276 target strains (i.e. strains belonging to the 38 species to be identified) and 122 non-target strains (i.e. strains not included in the array), were analysed by the array. Four target strains (three reference strains and one clinical isolate) produced discrepant identification by array hybridization. Three of the four discordant strains were found to be correctly identified by the array, as confirmed by sequencing of the ITS and 16S rRNA genes, with the remaining one being an unidentified species. The sensitivity and specificity of the array for identification of non-fermenters were 100 and 96.7%, respectively. In summary, the oligonucleotide array described here offers a very reliable method for identification of clinically relevant non-fermenters, with results being available within one working day.

[Effect of electroacupuncture on plasma estrin and bone mineral density in ovariectomized rats].

OBJECTIVE: To observe the effect of electroacupuncture (EA) on plasma estrin (E) 2 and bone mineral density (BMD) in ovariectomized (OVX) rats for studying its underlying mechanism in treating osteoporosis. METHODS: Thirty-two female SD rats were randomized into normal control, model, EA, and medication groups with 8 rats in each group. Postmenopausal osteoporosis model was established by removing the uterus under anesthesia (2% Phenobarbital, 40 mg/kg). In EA group, bilateral "Zusanli" (ST 32) and "Sanyinjiao" (SP 6) were punctured and stimulated electrically for 20 minutes with 1-3 Hz in frequency, 1 ms in duration of waves, and 0.7-1.0 mA in strength, once daily and 8 weeks altogether. Rats of medication group were drenched with 5% Nilestriol, 5 mL/week and for 8 weeks. At the end of experiments, blood samples were collected after removing the rat eyeball, and the left femoral bone tissue was taken. Serum E2 was assayed by using enzyme linked immunosorbent assay (ELISA) and BMD was measured by using double functional X-ray digital bone density meter. RESULTS: Compared with normal group, the body weight of model group was significantly bigger (P < 0.05), and that of model group was also significantly bigger than that of EA and medication groups (P < 0.11). No significant differences were found among the 4 groups before experiments and among normal control and EA groups after treatment (P > 0.05). In comparison with normal group, BMD and serum E2 of model group decreased significantly (P < 0. 01), while compared with model group, BMD and E2 of EA and medication groups increased significantly (P < 0.01, < 0.05). No significant differences were found among normal, EA and medication groups (P > 0.05). CONCLUSION: Both EA and medication can increase BMD and serum E2 in OVX rats, which may be one of the mechanisms of acupuncture in treating osteoporosis.

Species-level identification of isolates of the Acinetobacter calcoaceticus-Acinetobacter baumannii complex by sequence analysis of the 16S-23S rRNA gene spacer region.

The species Acinetobacter calcoaceticus, A. baumannii, genomic species 3, and genomic species 13TU included in the Acinetobacter calcoaceticus-Acinetobacter baumannii complex are genetically highly related and difficult to distinguish phenotypically. Except for A. calcoaceticus, they are all important nosocomial species. In the present study, the usefulness of the 16S-23S rRNA gene intergenic spacer (ITS) sequence for the differentiation of (genomic) species in the A. calcoaceticus-A. baumannii complex was evaluated. The ITSs of 11 reference strains of the complex and 17 strains of other (genomic) species of Acinetobacter were sequenced. The ITS lengths (607 to 638 bp) and sequences were highly conserved for strains within the A. calcoaceticus-A. baumannii complex. Intraspecies ITS sequence similarities ranged from 0.99 to 1.0, whereas interspecies similarities varied from 0.86 to 0.92. By using these criteria, 79 clinical isolates identified as A. calcoaceticus (18 isolates) or A. baumannii (61 isolates) with the API 20 NE system (bioMerieux Vitek, Marcy l'Etoile, France) were identified as A. baumannii (46 isolates), genomic species 3 (19 isolates), and genomic species 13TU (11 isolates) by ITS sequencing. An identification rate of 96.2% (76 of 79 isolates) was obtained by using ITS sequence analysis for identification of isolates in the A. calcoaceticus-A. baumannii complex, and the accuracy of the method was confirmed for a subset of strains by amplified rRNA gene restriction analysis and genomic DNA analysis by AFLP analysis by using libraries of profiles of reference strains. In conclusion, ITS sequence-based identification is reliable and provides a promising tool for elucidation of the clinical significance of the different species of the A. calcoaceticus-A. baumannii complex.