Intracellular Metabolic Changes of Rhodococcus sp. LH During the Biodegradation of Diesel Oil.

In recent years, some marine microbes have been used to degrade diesel oil. However, the exact mechanisms underlying the biodegradation are still poorly understood. In this study, a hypothermophilous marine strain, which can degrade diesel oil in cold seawater was isolated from Antarctic floe-ice and identified and named as Rhodococcus sp. LH. To clarify the biodegradation mechanisms, a gas chromatography-mass spectrometry (GC-MS)-based metabolomics strategy was performed to determine the diesel biodegradation process-associated intracellular biochemical changes in Rhodococcus sp. LH cells. With the aid of partial least squares-discriminant analysis (PLS-DA), 17 differential metabolites with variable importance in the projection (VIP) value greater than 1 were identified. Results indicated that the biodegradation of diesel oil by Rhodococcus sp. LH was affected by many different factors. Rhodococcus sp. LH could degrade diesel oil through terminal or sub-terminal oxidation reactions, and might also possess the ability to degrade aromatic hydrocarbons. In addition, some surfactants, especially fatty acids, which were secreted by Rhodococcus into medium could also assist the strain in dispersing and absorbing diesel oil. Lack of nitrogen in the seawater would lead to nitrogen starvation, thereby restraining the amino acid circulation in Rhodococcus sp. LH. Moreover, nitrogen starvation could also promote the conversation of relative excess carbon source to storage materials, such as 1-monolinoleoylglycerol. These results would provide a comprehensive understanding about the complex mechanisms of diesel oil biodegradation by Rhodococcus sp. LH at the systematic level.

Determination of perchlorate from tea leaves using quaternary ammonium modified magnetic carboxyl-carbon nanotubes followed by liquid chromatography-tandem quadrupole mass spectrometry.

The novel quaternary ammonium modified magnetic carboxyl-carbon nanotubes (QA-Mag-CCNTs) have been synthesised and characterized. QA-Mag-CCNTs were applied in magnetic dispersive solid phase extraction (Mag-dSPE) for preconcentration of perchlorate from tea leaves prior to liquid chromatography-tandem quadrupole mass spectrometry (LC-MS/MS) analysis. The Mag-dSPE procedure for preconcentration of perchlorate succeed in overcoming the flaw (containing target analyte randomly) of commercially available SPE cartridge. Under optimal conditions, the results showed higher extraction efficiency of QA-Mag-CCNTs, with recoveries between 85.2% and 107%. And the satisfactory precision with inter-day and intra-day RSD values were lower than 8.0%. Furthermore, QA-Mag-CCNTs were evaluated for reuse up to 20 times. The limit of quantification (LOQ) for perchlorate was 8.21 ng kg-1. The developed method was successfully applied in tea leaves for food-safety risk monitoring in Zhejiang province, China. The results showed the concentrations of perchlorate in 229 out of 240 collected samples were in the range of 0.082-988 µg kg-1. It was confirmed that QA-Mag-CCNTs were highly effective materials used for preconcentration of perchlorate.

[The analysis of the test results in HIV screening laboratory of Beijing Friendship Hospital in 2008].

OBJECTIVE: According to test results of the Hospital of AIDS screening laboratory in 2008, after counting analysis to assess the prevalence of AIDS, we can early detect positive cases in the future and effectively control the spread of AIDS. METHODS: All serum samples were screened by ELISA method and we reexaminated the samples by PA. As long as one result is positive by the two methods, then we sent the positive samples to Beijing Center for Disease Control and Prevention by Western Blot method to confirm the result. RESULTS: A total of 21 467 samples were detected and 29 (13.5% 0) were positive screening results. We confirm there were 7 (24.1%) positive samples and 12 (41.4%) suspected samples. We researched the epidemiology of the specimens by its source and age and sex. CONCLUSION: Application of ELISA method for HIV screening test has a practical significance, it is accurate and fit to record the results of the screening test for AIDS.

[In vitro inhibition of respiratory syncytial virus with combined ribavirin and an oral preparation of traditional Chinese medicine Hu Fei].

OBJECTIVE: To study the in vitro antiviral effect of ribavirin combined with an oral preparation of traditional Chinese medicine "Hu Fei" (protecting the lung) on respiratory syncytial virus (RSV). METHODS: Cytopathic effects (CEP) of RSV on Hep2 cells were observed after adding different concentrations of ribavirin, Hu Fei and combination of both into the culture medium. RESULTS: The minimum concentration of ribavirin and Hu Fei for complete inhibition of CPE caused by RSV was 7.80 microg/ml and 5.00 mg/ml, respectively. When the combination of ribavirin and Hu Fei was applied, their minimum concentrations needed for complete inhibition were decreased to 0.98 ?g/ml and 0.63 mg/ml. CONCLUSIONS: Both ribavirin and Hu Fei showed in vitro anti-RSV effect, but the inhibitory effect of combined ribavirin and Hu Fei was more potent than either of the preparation alone.