Tianzhi Li

Impact of simulated microgravity on microvascular endothelial cell apoptosis

Cardiovascular deconditioning is known to occur in astronauts exposed to microgravity. Endothelial dysfunction at microcirculatory sites might contribute to cardiovascular deconditioning induced by weightlessness. Recent studies have reported changes in the morphology and gene expression of endothelial cells exposed to conditions of simulated microgravity. The present study was aimed at examining the effects of microgravity on the apoptosis of microvascular endothelial cells and the mechanism underlying these effects. We simulated a microgravity environment and found that microgravity induced microvascular endothelial cell apoptosis and that this effect was correlated with the downregulation of the PI3K/Akt pathway, increased expression of NF-κB, and depolymerization of F-actin. These findings may provide important insights into the origin of the adverse physiological changes occurring due to exposure to microgravity conditions.

Draft Genome Sequence of Pseudomonas aeruginosa Strain ATCC 27853

Pseudomonas aeruginosa is a common bacterium that can cause disease. The versatility of Pseudomonas aeruginosa enables the organism to infect damaged tissues or those with reduced immunity which cause inflammation and sepsis. Here we report the genome sequence of the strain ATCC 27853.

Draft Genome Sequence of Escherichia coli LCT-EC106

Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the intestine of warm-blooded organisms. Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans. Here, we present the complete genome sequence of Escherichia coli LCT-EC106, which was isolated from CGMCC 1.2385.

High levels of inflammation and insulin resistance in obstructive sleep apnea patients with hypertension.

AbstractsHypertension induced by obstructive sleep apnea (OSA) may be multifactorial in origin, and systemic inflammation is one of the major factors. However, OSA patients do not always have the identical probability with hypertension even in patients with the same history and degree of OSA. The aim of this study was to compare the levels of inflammation and insulin resistance in two groups of patients who had the same degree as well as the same long history of OSA, but with/without hypertension. OSA patients (Apnea Hyponea Index, AHI ≥ 40/h, n = 70) were examined by polysomnography and blood analysis for the measurements of fasting plasma glucose, serum insulin (FINS), high-sensitivity C-reactive protein (CRP), peptide C,TNF-α, IL-6, and IL-10. Patients with hypertension (n = 40) had higher level of LDL-C and lower HDL-C levels than patients without hypertension. Almost half (16/40) of OSA patients with hypertension had family history of hypertension. Moreover in OSA patients with hypertension, the levels of TNF-α, IL-6, and CRP were higher, but IL-10 was lower than those without hypertension. FINS, peptide C, HOMA-IR, and HOMA-islet were also higher in OSA patients with hypertension. OSA patients with hypertension have higher level of inflammation and insulin resistance. Systemic inflammation and insulin resistance are both important factors for the development of hypertension in OSA patients.

A multi-omic analysis of an Enterococcus faecium mutant reveals specific genetic mutations and dramatic changes in mRNA and protein expression

BackgroundFor a long time, Enterococcus faecium was considered a harmless commensal of the mammalian gastrointestinal (GI) tract and was used as a probiotic in fermented foods. In recent decades, E. faecium has been recognised as an opportunistic pathogen that causes diseases such as neonatal meningitis, urinary tract infections, bacteremia, bacterial endocarditis and diverticulitis. E. faecium could be taken into space with astronauts and exposed to the space environment. Thus, it is necessary to observe the phenotypic and molecular changes of E. faecium after spaceflight.ResultsAn E. faecium mutant with biochemical features that are different from those of the wild-type strain was obtained from subculture after flight on the SHENZHOU-8 spacecraft. To understand the underlying mechanism causing these changes, the whole genomes of both the mutant and the WT strains were sequenced using Illumina technology. The genomic comparison revealed that dprA, a recombination-mediator gene, and arpU, a gene associated with cell wall growth, were mutated. Comparative transcriptomic and proteomic analyses showed that differentially expressed genes or proteins were involved with replication, recombination, repair, cell wall biogenesis, glycometabolism, lipid metabolism, amino acid metabolism, predicted general function and energy production/conversion.ConclusionThis study analysed the comprehensive genomic, transcriptomic and proteomic changes of an E. faecium mutant from subcultures that were loaded on the SHENZHOU-8 spacecraft. The implications of these gene mutations and expression changes and their underlying mechanisms should be investigated in the future. We hope that the current exploration of multiple “-omics” analyses of this E. faecium mutant will provide clues for future studies on this opportunistic pathogen.

Simulated microgravity alters the metastatic potential of a human lung adenocarcinoma cell line

Simulated microgravity (SM) has been implicated in affecting diverse cellular pathways. Although there is emerging evidence that SM can alter cellular functions, its effect in cancer metastasis has not been addressed. Here, we demonstrate that SM inhibits migration, gelatinolytic activity, and cell proliferation of an A549 human lung adenocarcinoma cell line in vitro. Expression of antigen MKI67 and matrix metalloproteinase-2 (MMP2) was reduced in A549 cells stimulated by clinorotation when compared with the 1×g control condition, while overexpression of each gene improves ability of proliferation and migration, respectively, under SM conditions. These findings suggest that SM reduced the metastatic potential of human lung adenocarcinoma cells by altering the expression of MKI67 and MMP2, thereby inhibiting cell proliferation, migration, and invasion, which may provide some clues to study cancer metastasis in the future.

Draft Genome Sequence of Serratia marcescens Strain LCT-SM213

Serratia marcescens is a species of Gram-negative, rod-shaped bacterium of the family Enterobacteriaceae. S. marcescens can cause nosocomial infections, particularly catheter-associated bacteremia, urinary tract infections, and wound infections. Here, we present the draft genome sequence of Serratia marcescens strain LCT-SM213, which was isolated from CGMCC 1.1857.

Whole-Genome Sequence of Klebsiella pneumonia Strain LCT-KP214

Klebsiella pneumoniae is a gram-negative, nonmotile, encapsulated, lactose-fermenting, facultative anaerobic, rod-shaped bacterium found in the normal flora of the mouth, skin, and intestines. Here we present the fine-draft genome sequence of K. pneumoniae strain LCT-KP214, which originated from K. pneumoniae strain CGMCC 1.1736.

Comparative genomic analysis of Klebsiella pneumonia (LCT-KP214) and a mutant strain (LCT-KP289) obtained after spaceflight

BackgroundWith the development of space science, it is important to analyze the relationship between the space environment and genome variations that might cause phenotypic changes in microbes. Klebsiella pneumoniae is commonly found on the human body and is resistant to multiple drugs. To study space-environment-induced genome variations and drug resistance changes, K. pneumoniae was carried into outer space by the Shenzhou VIII spacecraft.ResultsThe K. pneumoniae strain LCT-KP289 was selected after spaceflight based on its phenotypic differences compared to the ground-control strain. Analysis of genomic structural variations revealed one inversion, 25 deletions, fifty-nine insertions, two translocations and six translocations with inversions. In addition, 155 and 400 unique genes were observed in LCT-KP214 and LCT-KP289, respectively, including the gene encoding dihydroxyacetone kinase, which generates the ATP and NADH required for microbial growth. Furthermore, a large number of mutant genes were related to transport and metabolism. Phylogenetic analysis revealed that most genes in these two strains had a dN/dS value greater than 1, indicating that the strain diversity increased after spaceflight. Analysis of drug-resistance phenotypes revealed that the K. pneumoniae strain LCT-KP289 was resistant to sulfamethoxazole, whereas the control strain, LCT-KP214, was not; both strains were resistant to benzylpenicillin, ampicillin, lincomycin, vancomycin, chloramphenicol and streptomycin. The sulfamethoxazole resistance may be associated with sequences in Scaffold7 in LCT-KP289, which were not observed in LCT-K214; this scaffold contained the gene sul1. In the strain LCT-KP289, we also observed a drug-resistance integron containing emrE (confers multidrug resistance) and ant (confers resistance to spectinomycin, streptomycin, tobramycin, kanamycin, sisomicin, dibekacin, and gentamicin). The gene ampC (confers resistance to penicillin, cephalosporin-ii and cephalosporin-i) was present near the integron. In addition, 30 and 26 drug-resistance genes were observed in LCT-KP289 and LCT-KP214, respectively.ConclusionsComparison of a K. pneumoniae strain obtained after spaceflight with the ground-control strain revealed genome variations and phenotypic changes and elucidated the genomic basis of the acquired drug resistance. These data pave the way for future studies on the effects of spaceflight.

Genome Sequence of Pseudomonas aeruginosa Strain LCT-PA220, Which Was Selected after Space Flight by Using Biolog's Powerful Carbon Source Utilization Technology

ABSTRACT To explore the changes of Pseudomonas aeruginosa in space flight, we present the draft genome sequence of P. aeruginosa strain LCT-PA220, which originated from a P. aeruginosa strain, ATCC 27853, that traveled on the Shenzhou-VIII spacecraft.