iTRAQ-Based Differential Proteomic Analysis Reveals the Pathways Associated with Tigecycline Resistance in Acinetobacter baumannii

Background/Aims: Acinetobacter baumannii is an aerobic and Gram-negative bacterial pathogen with high morbidity and mortality. It remains a serious public health problem arising from its multidrug-resistant and extensive antibiotic resistance spectrum. Methods: In the present study, iTRAQ coupled with 2D LC-MS/MS was used to evaluate the proteome in standard Acinetobacter baumannii standard strains and tigecycline-resistant strains. Results: A total of 3639 proteins were identified and 961 proteins were identified to be differentially expressed in tigecycline-resistant Acinetobacter baumannii strains compared to the standard strains. 506 (52.6%) proteins were up-regulated and 455 (47.4%) proteins were down-regulated. Based on the GO enrichment analysis and KEGG pathway analysis, we concluded that most differentially expressed proteins were associated with stress responses, cellular component organization, proteins synthesis, degradation and function. Moreover, β-lactam resistance, the longevity regulating pathway and other related pathways were also involved in the regulation of tigecycline-resistant Acinetobacter baumannii. The differential expression of key proteins were evaluated by transcript analysis using quantitative RT-PCR. Conclusion: These results may provide new insights into the mechanisms of drug resistance in Acinetobacter baumannii

Development and validation of a HPLC/FLD method combined with online derivatization for the simple and simultaneous determination of trace amino acids and alkyl amines in continental and marine aerosols.

A method was developed for simultaneous determination of 15 amino acids and 7 alkyl amines. The method was based on the employment of high performance liquid chromatography/fluorescence detection and online derivatization with o-phthaldiadehyde. The 22 derivatives were separated within 30 min including the equilibration time and detected by a fluorescence detector at an excitation wavelength of 230 nm and emission wavelength of 450 nm. The analysis procedure was satisfactorily validated by the reproducibility, recovery, linearity and detection limit of the analytes. The relative standard deviations (RSDs) of retention time and peak area for individual amino acids and alkyl amines were consistently less than 0.30% and 2.35%, respectively. Good recovery values ranging from 70% to 109% were obtained. The proposed method showed good linearity (R2≥0.99) in the range of 0.125-125 μM/L for amino acids and 2.5-5000 ng/L for alkyl amines. The detection limit ranged from 0.13 pM to 0.37 pM for individual amino acids and from 0.9 ng to 7.2 ng for individual alkyl amines. The developed and validated method was successfully applied to the quantitative analysis of amino acids and alkyl amines in continental and marine aerosols in China. Among the identified organic nitrogen compounds, 7 amino acids and 6 alkyl amines were detected in every aerosol sample. Glycine was the dominant amino acid, with the average of 130.93 pmol/m3 (accounting for 83% of the total amino acids) and 137.22 pmol/m3 (accounting for 66% of the total amino acids) in continental and marine aerosols in China, respectively. Methylamine and ethanolamine were the most abundant alkyl amines, contributing 87% and 64% to the total alkyl amines in continental and marine aerosols in China, respectively. This work provided an accurate, sensitive and simple method to determine simultaneously amino acids and alkyl amines, and applied the proposed method to the first investigation of amino acids in Shanghai and amino acids and alkyl amines in Huaniao Island in China. The finding of considerable amino acids and alkyl amines in continental and marine aerosols may exert significant implications on nitrogen cycling and atmospheric chemistry

Dynamic Balance Measurement and Quantitative Assessment Using Wearable Plantar-Pressure Insoles in a Pose-Sensed Virtual Environment

The center of plantar pressure (COP) reflects the dynamic balance of subjects to a certain extent. In this study, wearable pressure insoles are designed, body pose measure is detected by the Kinect sensor, and a balance evaluation system is formulated. With the designed games for the interactive actions, the Kinect sensor reads the skeletal poses to judge whether the desired action is performed, and the pressure insoles simultaneously collect the plantar pressure data. The COP displacement and its speed are calculated to determine the body sway and the ability of balance control. Significant differences in the dispersion of the COP distribution of the 12 subjects have been obtained, indicating different balancing abilities of the examined subjects. A novel assessment process is also proposed in the paper, in which a correlation analysis is made between the de facto sit-to-stand (STS) test and the proposed method; the Pearson and Spearman correlations are also conducted, which reveal a significant positive correlation. Finally, four undergraduate volunteers with a right leg sports injury participate in the experiments. The experimental results show that the normal side and abnormal side have significantly different characters, suggesting that our method is effective and robust for balance measurements

Chronic intermittent hypobaric hypoxia provides vascular protection in aorta of two-kidney one clip rat model of hypertension

Many studies have demonstrated that chronic intermittent hypobaric hypoxia (CIHH) can reduce blood pressure in spontaneously hypertensive rats and renovascular hypertensive (RVH) rats in which endothelial dysfunction is determined as a critical factor. However, whether CIHH can regulate vasodilation of the aorta in RVH rats remains unknown. The purpose of this study was to investigate the effect of CIHH on impaired relaxation of the aorta in the two-kidney one-clip (2K1C) RVH rat model. The results showed CIHH improved the impaired endothelium-dependent relaxation in the 2K1C rat aorta. The endothelial dysfunction was prevented by the p38 antagonist SB203580, but not by the ERK1/2 antagonist PD98059 or JNK antagonist SP600125. Furthermore, the expression of p-eNOS, HIF-1É and HIF-2É increased while that of p-p38 and BMP-4 decreased in CIHH-treated aortas from 2K1C rats. Finally, the p-eNOS expression was up-regulated and the p-p38 expression was down-regulated by pre-incubation of SB203580 or the BMP-4 antagonist Noggin with the aorta. In conclusion, CIHH ameliorated the impairment of endothelium-dependent relaxation through up-regulating the expression of p-eNOS which may be mediated by the inhibition of BMP-4 / p-p38 MAPK and up-regulating the expression of HIFs in the 2K1C rat aorta.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author