Simulation stress model of the undersea environment activates the central nervous, neuroendocrine and immune systems and anxiety in rats.

The present study was designed to assess the stress responses to a simulation model of the undersea environment that is similar to some undersea working conditions such as submarine rescue, underwater salvage and underwater construction. Restraint, hyperbaric air and immersion were chosen to produce the simulation stress model in rats for four hours. Rats were randomized into five groups: control group, restraint (R) group, hyperbaric air (H) group, restraint plus hyperbaric air (RH) group, and restraint plus hyperbaric air plus immersion (RHI) group. The results showed that the responses to the simulation stress model of the undersea environment induced by R, H, RH and RHI involved the upregulated norepinephrine (NE), dopamine (DA) and 5-hydroxytryptamine (5-HT) of the central nervous system (CNS), upregulated adrenocorticotropic hormone (ACTH), corticosterone (CORT) and blood glucose of the neuroendocrine system, upregulated interleukin-1 (IL-1), interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) of the immune system, and increased anxiety in rats. Compared with hyperbaric air, restraint tended to activate stronger stress responses. Conclusively, this work established a simulation stress model of the undersea environment induced by restraint, hyperbaric air and immersion. It further provided experimental data of such a model that showed significant activation of the CNS, neuroendocrine and immune systems and anxiety in rats. In this experiment we provided an experimental basis for undersea work such as working aboard a submarine.

Multilocus sequencing typing of Pseudomonas aeruginosa isolates and analysis of potential pathogenicity of typical genotype strains from occupational oxyhelium saturation divers.

BACKGROUND: Pseudomonas aeruginosa (P. aeruginosa) is a common microbe isolated from divers with ear and skin infections. To obtain the epidemic characters of the occurrence of the P. aeruginosa infection, multilocus sequence typing (MLST) was used to assess the genetic background of different strains isolated from divers involved in saturation diving. METHODS: A total of 64 P. aeruginosa strains from naval divers were sequenced by multilocus sequence typing using seven housekeeping genes (acsA, aroE, guaA, mutL, nuoD, ppsA and trpE). The results were analyzed based on the P. aeruginosa international MLST database to obtain the allelic profiles and sequence types (STs). MLST data were analyzed by Bionumerics 4.0 (http: // pubmlst.org/mlstanalyse) using LIAN and eBURST. Twenty-eight strains with the typical genotype were selected for further analysis of pathogenic characteristics by Caenorhabditis elegans (C. elegans) fast killing model. RESULTS: Data from MLST revealed a high STs diversity among the strains. Of the 64 strains, 53 strains were assigned to 19 STs, and the remaining 11 clones could not be assigned. ST274 accounted for 18.5% (12/64), and ST260 accounted for 15.62% (10/64). C. elegans killing assay showed that all the test strains had distinct virulent properties as compared with the negative control group. Clone 503-1 had the highest virulence and clone 54 had the lowest virulence as compared with the positive clinical group. CONCLUSION: The P. aeruginosa strains carried by the occupational diver groups in Chinese regions have characteristically dominant STs, and have a relatively strong virulence as compared with the standard strain and the clinically isolated positive control strain.

Microarray analysis and phenotypic response of Pseudomonas aeruginosa PAO1 under hyperbaric oxyhelium conditions.

Pseudomonas aeruginosa is an important opportunistic pathogen associated with multiple diseases including cystic fibrosis and nosocomial infections. Pseudomonas aeruginosa is also the microbe most often isolated from ear and skin infections in divers. Saturation divers often suffer from various skin and mucous disorders, of which P. aeruginosa infections are the most serious and frequent. Previous studies mainly focused on adaptive and regulatory mechanisms of P. aeruginosa virulence in inducing clinical acute and chronic infections under different environmental conditions. However, there are few studies describing the physiological adaptive and regulatory mechanisms of P. aeruginosa in inducing high infectivity in healthy divers under hyperbaric oxyhelium conditions and even fewer studies describing the overall influence of the hyperbaric oxyhelium environment on regulating mRNA and protein expression levels of P. aeruginosa. The present study used transcriptomic and virulence phenotype analysis to identify factors that allow P. aeruginosa to become established in a hyperbaric oxyhelium environment to facilitate infections in divers. Transcriptional profiling of P. aeruginosa grown under steady-state hyperbaric oxyhelium stress conditions showed an upregulation of genes associated with stress-sense/response, protein folding, transcriptional regulation, pili and flagellum metabolism, virulence adaptation, and membrane protein metabolism. Some of these genes (including several two-component systems not previously known to be influenced by hyperbaric oxyhelium) were differentially expressed by P. aeruginosa in response to 72 h of exposure to hyperbaric oxyhelium stress. Detection of the virulence phenotype confirmed the results of cDNA microarrays. Based on these results, we conclude that hyperbaric oxyhelium conditions affect PAO1 gene expression and upregulate the expression of most virulence genes. The data obtained in our study may provide new insight into the molecular mechanism of hyperbaric oxyhelium exposure against P. aeruginosa virulence adaptation.

Identification of Y118 amino acid residue in Candida albicans sterol 14alpha-demethylase associated with the enzyme activity and selective antifungal activity of azole analogues.

Our previous publication established a model to predict that the phenyl group of the C-3 side chain of azole antifungal compounds interacts with the phenol group of Tyr118 through the formation of pi-pi face-to-edge interaction. To verify this prediction, wild type and three site-directed mutants of the Y118 residue of Candida albicans sterol 14alpha-demethylase P450 (CACYP51) were constructed and heterologously expressed in Saccharomyces cerevisiae with deletion of the CYP51 gene. With the strains obtained and microsome enzymes separated, cell susceptibility and CACYP51 activity were examined with the 5 novel azole compounds based on the molecular modeling in comparison with fluconazole. After alteration of Y118 with Y118A, Y118F, and Y118T by a single base substitution, the expression levels of CACYP51 protein were not affected. However, these mutations markedly decreased its catalytic activity respectively; the mutation changes also decreased azole susceptibility, indicating the structural importance of the Y118 residue in maintaining CACYP51 activity and in determining azole susceptibility. In addition, our synthetic compounds with the phenyl group side chain attached to C3 produced higher susceptibility against S. cerevisiae with expression of CACYP51 and exhibited more potent inhibitory effects on CACYP51 activity in comparison with fluconazole, suggesting that the phenyl group of C3 side chain substitutes is also important for selective binding to target enzymes.

[The effects of cell growth factors on proliferation and migration of coronary artery endothelial cells].

AIM: To study the effects of hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) on proliferation and migration of bovine coronary artery endothelial cells (BCAEC) in vitro. METHODS: BCAECs were isolated and cultured in vitro, and divided into control group, VEGF group and HGF group. BCACEs proliferation were measured using MTT, and their migration was observed using reverse microscope. RESULTS: The OD value of control, VEGF and HGF group were 0.22 +/- 0.01, 0.40 +/- 0.14, 0.44 +/- 0.15 respectively. The proliferation ratio of BCAECs in VEGF and HGF group was 81.8% +/- 16.9%, 100.0% +/- 21.1% respectively. There was no migration in control group, but significant migration in VEGF and HGF group. CONCLUSION: Both VEGF and HGF can promote proliferation and migration of BCAECs, the effect of HGF is stronger than VEGF.