[Association and gender difference analysis of obstructive sleep apnea hypopnea syndrome and liver injury].

Objective: To investigate the correlation and sex difference between obstructive sleep apnea hypopnea syndrome (OSAHS) and liver injury. Methods: A total of 974 OSAHS patients (444 cases of mild to moderate, 530 cases of severe) and 111 cases of simple snoring in the First Affiliated Hospital of Fujian Medical University and Zhangzhou Municipal Hospital from November 2015 to September 2019 were included in the study. The basic information of the patients was obtained through face-to-face survey with self-made questionnaire, physical examination, sleep monitoring and blood biochemical and liver function index detection were carried out among the included subjects. Multiple logistic regression model was used to analyze the correlation between OSAHS and liver injury and the gender differences. Results: The subjects were (50±14) years old, including 841 males (77.5%). Statistically significant differences in total cholesterol (TC), triglycerides (TG), low density lipoprotein-cholesterol (LDL-C), high density lipoprotein-cholesterol (HDL-C), fasting blood glucose, alamine aminotransferase (ALT), aspartate aminotransferase (AST), ALT/AST, gamma glutamyltransferase (GGT), the rate of elevated ALT, AST and liver injury were observed among the three groups (all P values<0.05). There was no significant difference in total bilirubin and ALP among all groups (all P values>0.05). Multivariate logistic regression showed that after adjusting for confounding factors, severe OSAHS was positively correlated with liver injury [OR (95%CI): 2.25 (1.22-4.14)]. Subgroup analysis by gender showed that severe OSAHS was positively correlated with liver injury in males [OR (95%CI): 2.20 (1.04-4.65)], but not in females, mild to moderate OSAHS [OR (95%CI): 1.56 (0.52-4.71)] or severe OSAHS [OR (95%CI): 2.07(0.64-6.75)], after adjusting for confounding factors. Conclusion: Severe OSAHS is positively correlated with liver injury in males, while female OSAHS is not associated with liver injury.

[Research progress on organoids in stomatology].

The organoid is a kind of distinctive micro-organ formed by stem cells with the ability of self-renewal, which can be cultured in three-dimensional scaffold in vitro. With the development of cell culture system, organoids have been gradually applied in researches such as in vitro organ model establishment, drug testing and even the repairing or replacing damage organs. It shows significantly promising prospects. This review article aims to summarize the latest research progress and provide the theoretical foundation and prospects for the development of organoids in stomatology.

Tunable Protein Hydrogels: Present State and Emerging Development.

In recent years, protein and peptide-based hydrogels have received great attention for applications in biomedicine. Compared to hydrogels based on synthetic materials, they have the decisive advantages of being biological origin, providing cells with a more in vivo-like microenvironment and possessing potential biological activity. Empowered by the steadily deepened understanding of the sequence-structure-function relationship of natural proteins and the rapid development of molecular-biological tools for accurate protein sequence editing, researchers have developed a series of recombinant proteins as building blocks and responsive blocks to design novel functional hydrogels. The use of multi-block design further expands the customizability of protein hydrogels. With the improvement of standardization of preparation and testing methods, protein hydrogels are expected to be widely used in medical treatment, skin care, artificial organs and wearable electronic devices. More recently, the emergence of catalytically active protein hydrogel brings new opportunities for applications of protein hydrogels. It is believed that through integrated approaches of engineering biology and materials sciences novel and hereto unthinkable protein hydrogels and properties may be generated for applications in areas beyond medicine and health, including biotechnology, food and agriculture, and even energy.

A tree-ring δ18O based reconstruction of East Asia summer monsoon over the past two centuries.

The East Asian summer monsoon (EASM) exhibits considerable decadal variations since the late 20th century. Efforts to examine long-term behaviors and dynamics of the EASM are impeded largely due to the shortness of instrumental meteorological records. So far, reconstructions of the EASM with annual resolution from its core regions remain limited. We conduct the first 200-year robust EASM reconstruction based on tree-ring cellulose δ18O records derived from Pinus massoniana trees growing in the middle Yangtze River basin, one of the core EASM areas. The δ18O chronology accounts for 46.2% of the actual variation in an index of the EASM from 1948 to 2014. The reconstructed EASM indicates that the monsoon intensity was below average before the 1950s, peaked in the 1950s-1970s, and then began to decline. The reconstructed EASM is negatively correlated with the El Niño-Southern Oscillation (ENSO), but this teleconnection is dynamic through time, i.e. enhanced (reduced) ENSO variability coheres with strong (weak) EASM-ENSO connections. In addition, despite high ENSO variability since the 1980s, the EASM-ENSO relationship weakened possibly due to anthropogenic impact, particularly aerosol emissions.

Use of the Veggie Meter® as a tool to objectively approximate fruit and vegetable intake among youth for evaluation of preschool and school-based interventions.

BACKGROUND: Reflection spectroscopy is an emerging, non-invasive objective measure used to approximate fruit and vegetable intake. The present study aimed to use a reflection spectroscopy device (the Veggie Meter®, Longevity Link Corporation, Salt Lake City, UT, USA) to assess skin carotenoid status in preschool, middle- and high-school students and to examine associations between skin carotenoids and self-reported dietary intake. METHODS: In Autumn 2018, we used the Veggie Meter® to assess skin carotenoids and age-appropriate validated dietary assessment measures to approximate fruit and vegetable (FV) intake. Preschool participants completed a previously validated pictorial liking tool using an iPad (Apple Inc., Cupertino, CA, USA). Middle-school participants completed selected questions from the validated School Physical Activity and Nutrition (SPAN) (Michael & Susan Dell Center for Healthy Living, University of Texas, Austin, TX, USA) questionnaire regarding frequency of their FV and beverage intake on the previous day, with additional questions about physical activity. High-school participants' FV intake was assessed using the Fruit and Vegetable Screener (National Cancer Institute, Bethesda, MD, USA). Spearman correlation coefficients were used to determine bivariate associations between measures of dietary intake and Veggie Meter®-assessed skin carotenoid levels. RESULTS: Mean (SD) Veggie Meter® readings were 266 (82.9), 219 (68.1) and 216 (67.2) among preschool, middle- and high-school students. There was an inverse association between soda intake and Veggie Meter® readings (r = -0.22, P = 0.03) among middle-school students; and a positive association between daily fruit intake and Veggie Meter® readings (r = 0.25, P = 0.06) among high-school students. CONCLUSIONS: The Veggie Meter® comprises a promising evaluation tool for preschool and school-based nutrition interventions.

[Effects of Spartina alterniflora invasion in a seaward direction on variations of inorganic sulfur forms in marsh soils of the Minjiang River estuary, China]. / é—½æ±Ÿæ²³å£äº’èŠ±ç±³è‰æµ·å‘å ¥ä¾µå¯¹æ¹¿åœ°åœŸå£¤æ— æœºç¡«èµ‹å­˜å½¢æ€çš„å½±å“.

To explore the effects of Spartina alterniflora invasion in a seaward direction on variations of inorganic sulfur forms in marsh soils, the levels of inorganic sulfur forms (H2O-S, Adsorbed-S, HCl-Soluble-S and HCl-Volatile-S) were determined in bare flat (BF, before invasion), S. alterniflora marsh after seaward invasion for one year (SA') and S. alterniflora marsh after seaward invasion for three years (SA) in Shanyutan of the Minjiang River estuary with the method of space-for-time substitution. Results showed that the seaward invasion of S. alterniflora altered the stocks and distribution of inorganic sulfur form in marsh soils. Compared with BF, the contents of H2O-S, Adsorbed-S and HCl-Volatile-S in soils of SA increased by 52.6%, 78.2% and 21.0%, respectively, while that of HCl-Soluble-S decreased by 3.4%. In contrast, the levels of H2O-S, Adsorbed-S and HCl-Soluble-S in soils of SA' increased by 43.9%, 70.6% and 29.6%, respectively, whereas that of HCl-Volatile-S decreased by 11.6%. The contents of total inorganic sulfur (TIS) in soils of SA and SA' increased by 40.7% and 37.8%, while the stocks of TIS increased by 26.8% and 31.4%, respectively. The key factors affecting different forms of inorganic sulfur in marsh soils had changed due to the seaward invasion of S. alterniflora. In particular, the key factors affecting the variations of H2O-S contents changed from soil grain composition and bulk density in BF to soil organic matter in SA' and SA. The seaward invasion of S. alterniflora significantly increased the content of TIS in marsh soils, which was mainly contributed by H2O-S and Adsorbed-S. Thus, it was concluded that the seaward invasion of S. alterniflora significantly increased the supply capacity of available sulfur in marsh soils, which, to some extent, accelerated its seaward invasion.

Tumour exosomes from cells harbouring PTPRZ1-MET fusion contribute to a malignant phenotype and temozolomide chemoresistance in glioblastoma.

Exosomes are carriers of pro-tumorigenic factors that participate in glioblastoma (GBM) progression, and many fusion genes are strong driver mutations in neoplasia and are involved in tumorigenesis. However, the ability of fusion genes to be transduced by exosomes is unknown. We characterized exosomes from GBM cells harbouring and not harbouring PTPRZ1-MET fusion (ZM fusion). We also determined the effect of the exosomes from ZM fusion cells (ZM exosomes) on pro-oncogenic secretions and showed that ZM exosomes are internalized by the recipient cells. In addition, we studied the effect of ZM exosome-mediated intercellular communication in the GBM microenvironment. MET proto-oncogene expression was higher in ZM exosomes. Moreover, phosphorylated MET was detected only in ZM exosomes and not in exosomes released by non-ZM fusion GBM cells. ZM exosomes transferred to non-ZM fusion GBM cells and normal human astrocytes altered gene expression and induced epithelial-mesenchymal transition. The uptake of ZM exosomes also induced an exosome-dependent phenotype defined by GBM cell migration and invasion, neurosphere growth and angiogenesis. In addition, ZM exosomes conferred temozolomide resistance to the GBM cells, and exosome-derived ZM fusion network proteins targeted multiple pro-oncogenic effectors in recipient cells within the GBM microenvironment. Our findings show that exosomes mediate the aggressive character of GBM and demonstrate the role of ZM fusion in the exacerbation of this effect. These findings have possible implications for the foundation of gene fusion-based therapy for managing GBM.

Nifuroxazide induces apoptosis and impairs pulmonary metastasis in breast cancer model.

Breast carcinoma is the most common female cancer with considerable metastatic potential. Signal transducers and activators of the transcription 3 (Stat3) signaling pathway is constitutively activated in many cancers including breast cancer and has been validated as a novel potential anticancer target. Here, we reported our finding with nifuroxazide, an antidiarrheal agent identified as a potent inhibitor of Stat3. The potency of nifuroxazide on breast cancer was assessed in vitro and in vivo. In this investigation, we found that nifuroxazide decreased the viability of three breast cancer cell lines and induced apoptosis of cancer cells in a dose-dependent manner. In addition, western blot analysis demonstrated that the occurrence of its apoptosis was associated with activation of cleaved caspases-3 and Bax, downregulation of Bcl-2. Moreover, nifuroxazide markedly blocked cancer cell migration and invasion, and the reduction of phosphorylated-Stat3(Tyr705), matrix metalloproteinase (MMP) MMP-2 and MMP-9 expression were also observed. Furthermore, in our animal experiments, intraperitoneal administration of 50 mg/kg/day nifuroxazide suppressed 4T1 tumor growth and blocked formation of pulmonary metastases without detectable toxicity. Meanwhile, histological and immunohistochemical analyses revealed a decrease in Ki-67-positive cells, MMP-9-positive cells and an increase in cleaved caspase-3-positive cells upon nifuroxazide. Notably, nifuroxazide reduced the number of myeloid-derived suppressor cell in the lung. Our data indicated that nifuroxazide may potentially be a therapeutic agent for growth and metastasis of breast cancer.

Comparative physiological study of the wild type and the small colony variant of Pseudomonas aeruginosa 20265 under controlled growth conditions.

Small-colony variants (SCVs) of Pseudomonas aeruginosa are often found in chronically infected airways of patients suffering from cystic fibrosis. These slow-growing morphological variants have been associated with persistent and antibiotic-resistant infections. Nevertheless, the behavior of SCVs under varied availability of O2 and iron, two key variables relevant to the lung environment of CF patients and pathogenicity of P. aeruginosa, has not been systematically studied so far. In this work, the effects of O2 and iron were comparatively studied for a CF P. aeruginosa wild type (WT) strain and its SCV phenotype in a real-time controlled cultivation system. Significant differences in the behavior of these strains were observed and quantified. In general, SCV exhibited a higher fitness than the WT toward aerobic conditions. Under iron rich condition, and despite less release of total extracellular proteins, absence of flagellin and lower siderophore production, the SCV cells grown at fully aerobic conditions showed a higher specific growth rate and a significantly higher cytotoxicity in comparison with the WT cells. The strains behaved also differently towards iron limitation. The phenomena of limited O2 transfer from the gas to the liquid phase and enhancement of formation of virulence factors under conditions of iron limitation were much more profound in the SCV culture than in the WT culture. These results have important implications for better understanding the pathogenicity of P. aeruginosa and its small-colony variants.

The effects of nucleoside analogue prophylactic treatment on HBV activation in HBcAb+ patients undergoing immunosuppressive therapy.

We investigated the effects of prophylactic nucleoside analogue treatment on HBV activation in patients with antibodies against core antigen (HBcAb+) patients undergoing immunosuppressive therapy. Patients (113), who were HBcAb+, with various autoimmune diseases, undergoing immunosuppressive therapy, were divided into two groups. The control group, not treated with antivirals, and the prophylactic group, treated with antiviral drugs. The two groups were evaluated for changes in serum biochemical marker (alanine aminotransferase ALT), virological marker (HBV DNA) and for seroconversion. In the control group, the number of patients with an increase in ALT in patients with isolated HBcAb and HBcAb and antibodies against HBsAg (HBsAb +) were five (20.0%) and one (2.8%), respectively (P < 0.05). There were six cases (24.0%) with an increase in HBV DNA in the isolated HBcAb+ subgroup and one case (2.8%) in HBsAb+/HBcAb+ subgroup (P < 0.05). In the HBcAb+ only population, six patients (24.0%) in the control group had an increase in HBV DNA compared with none in the antiviral prophylactic group (P < 0.05). One patient (4.0%) with HBcAb+ in the control group underwent an HBsAg seroconversion when receiving immunosuppressive therapy for 18 months, while none in the antiviral prophylactic group underwent reversion to HBsAg positivity (P = 0.4949). Under immunosuppressive condition, the risk of HBV activation was much higher in patients with HBcAb than in patients with both HBcAb and antibodies to HBsAb group. Antiviral prophylactic therapy could significantly reduce the risk of HBV reactivation.

Compartmentalization and metabolic channeling for multienzymatic biosynthesis: practical strategies and modeling approaches.

: The construction of efficient enzyme complexes for multienzymatic biosynthesis is of increasing interest in order to achieve maximum yield and to minimize the interference due to shortcomings that are typical for straightforward one-pot multienzyme catalysis. These include product or intermediate feedback inhibition, degeneration, and diffusive losses of reaction intermediates, consumption of co-factors, and others. The main mechanisms in nature to tackle these effects in transient or stable protein associations are the formation of metabolic channeling and microcompartments, processes that are desirable also for multienzymatic biosynthesis in vitro. This chapter provides an overview over two main aspects. First, numerous recent strategies for establishing compartmentalized multienzyme associations and constructed synthetic enzyme complexes are reviewed. Second, the computational methods at hand to investigate and optimize such associations systematically, especially with focus on large multienzyme complexes and metabolic channeling, are discussed. Perspectives on future studies of multienzymatic biosynthesis concerning compartmentalization and metabolic channeling are presented.

Substrate-limited co-culture for efficient production of propionic acid from flour hydrolysate.

Propionic acid is presently mainly produced by chemical synthesis. For many applications, especially in feed and food industries, a fermentative production of propionic acid from cheap and renewable resources is of large interest. In this work, we investigated the use of a co-culture to convert household flour to propionic acid. Batch and fed-batch fermentations of hydrolyzed flour and a process of simultaneous saccharification and fermentation were examined and compared. Fed-batch culture with substrate limitation was found to be the most efficient process, reaching a propionic acid concentration of 30 g/L and a productivity of 0.33 g/L*h. This is the highest productivity so far achieved with free cells on media containing flour hydrolysate or glucose as carbon source. Batch culture and culture with controlled saccharification and fermentation delivered significantly lower propionic acid production (17-20 g/L) due to inhibition by the intermediate product lactate. It is concluded that co-culture fermentation of flour hydrolysate can be considered as an appealing bioprocess for the production of propionic acid.

Case-control association analysis of polymorphisms in the δ-opioid receptor, OPRD1, with cocaine and opioid addicted populations.

BACKGROUND: Addiction susceptibility and treatment responsiveness are greatly influenced by genetic factors. Sequence variation in genes involved in the mechanisms of drug action have the potential to influence addiction risk and treatment outcome. The opioid receptor system is involved in mediating the rewarding effects of cocaine and opioids. The µ-opioid receptor (MOR) has traditionally been considered the primary target for opioid addiction. The MOR, however, interacts with and is regulated by many known MOR interacting proteins (MORIPs), including the δ-opioid receptor (DOR). METHODS: The present study evaluated the contribution of OPRD1, the gene encoding the DOR, to the risk of addiction to opioids and cocaine. The association of OPRD1 polymorphisms with both opioid addiction (OA) and cocaine addiction (CA) was analyzed in African American (OA n=336, CA n=503) and European American (OA n=1007, CA n=336) populations. RESULTS: The primary finding of this study is an association of rs678849 with cocaine addiction in African Americans (allelic p=0.0086). For replication purposes, this SNP was analyzed in a larger independent population of cocaine addicted African Americans and controls and the association was confirmed (allelic p=4.53 × 10(-5); n=993). By performing a meta-analysis on the expanded populations, the statistical evidence for an association was substantially increased (allelic p=8.5 × 10(-7)) (p-values non-FDR corrected). CONCLUSION: The present study suggests that polymorphisms in OPRD1 are relevant for cocaine addiction in the African American population and provides additional support for a broad role for OPRD1 variants in drug dependence.

Microtechnology meets systems biology: the small molecules of metabolome as next big targets.

One of the key objectives of systems biology is to study and control biological processes in terms of interactions of components at different molecular levels. Advances in genome sequencing, transcriptomics and proteomics have paved the way for a systemic analysis of cellular processes at gene and protein levels. However, tools are still missing for a reliable and systemic analysis of the small molecules inside cells, the so-called metabolome. Due to the generally very low concentration, high turn-over rate and chemical diversity of metabolites their quantification under physiological, in vivo and dynamic conditions presents major challenges and the missing link for a real systems biology approach on the way from genome to cellular function. To this end, microfluidics can play an important role owing to its unique characteristics such as highly spatial and temporal resolution of sample treatment and analysis. Despite impressive progresses in microtechnology in recent years, many of the microfluidic studies or devices remain at the level of proof-of-principle and have been seldom applied to the real world of metabolomic analysis. In this review article, we first present the major obstacles and challenges for determining in vivo metabolite dynamics in complex biological systems. The progresses in microfluidics, their characteristics and possible applications to solving some of the compelling problems in metabolomic analysis are then discussed. Emphases are put on pinpointing the deficits of the presently available devices and technologies and directions for further development to fulfill the special need of systems biology.

Wnt signaling and stem cell control.

In many contexts, self-renewal and differentiation of stem cells are influenced by signals from their environment, constituting a niche. It is postulated that stem cells compete for local growth factors in the niche, thereby maintaining a balance between the numbers of self-renewing and differentiated cells. A critical aspect of the niche model for stem cell regulation is that the availability of self-renewing factors is limited and that stem cells compete for these factors (Fig. 1). Consequently, the range and concentrations of the niche factors are of critical importance. Now that some of the few self-renewing factors have become identified, aspects of the niche models can be tested experimentally. In this chapter, we address mechanisms of signal regulation that take place at the level of signal-producing cells, constituting a niche for stem cells. We emphasize the biochemical properties and posttranslational modifications of the signals, all in the context of Wnt signaling. We propose that these modifications control the range of Wnt signaling and have critical roles in establishing niches for stem cells in various tissues.

Practical application of different enzymes immobilized on sepabeads.

The immobilization of an endoglucanase, benzoylformate decarboxylase (BFD) from Pseudomonas putida, as well as of lipase B from Candida antarctica (CALB) onto the carrier supports Sepabeads EC-EP, Sepabeads EC-EA, and Sepabeads EC-BU was accomplished. It is shown that via these immobilized biocatalysts the synthesis of both fine and bulk chemicals is possible. This is illustrated by the syntheses of polyglycerol esters and (S)-hydroxy phenyl propanone. The benefit of immobilization is illustrated by repetitive use in a bubble column reactor as well as in a stirred tank reactor. High stability of two biocatalysts was achieved and reusability up to eight times was demonstrated. The comparison of CALB immobilized on Sepabeads EC-EP to Novozym 435 shows similar activity.

[Equilibrium sorption isotherm for Cu2+ onto Hydrilla verticillata Royle and Myriophyllum spicatum].

Equilibrium sorption isotherms for Cu2+ onto Hydrilla verticillata Royle and Myriophyllum spicatum were studied. Both methods of linear and non-linear fitting were applied to describe the sorption isotherms, and their applicability were analyzed and compared. The results were: (1) The applicability of simulated equation can't be compared only by R2 and chi2 when equilibrium sorption model was used to quantify and contrast the performance of different biosorbents. Both methods of linear and non-linear fitting can be applied in different fitting equations to describe the equilibrium sorption isotherms respectively in order to obtain the actual and credible fitting results, and the fitting equation best accorded with experimental data can be selected; (2) In this experiment, the Langmuir model is more suitable to describe the sorption isotherm of Cu2+ biosorption by H. verticillata and M. spicatum, and there is greater difference between the experimental data and the calculated value of Freundlich model, especially for the linear form of Freundlich model; (3) The content of crude cellulose in dry matter is one of the main factor affecting the biosorption capacity of a submerged aquatic plant, and -OH and -CONH2 groups of polysaccharides on cell wall maybe are active center of biosorption; (4) According to the coefficients qm of the linear form of Langmuir model, the maximum sorption capacity of Cu2+ was found to be 21.55 mg/g and 10.80mg/g for H. verticillata and M. spicatum, respectively. The maximum specific surface area for H. verticillata for binding Cu2+ was 3.23m2/g, and it was 1.62m2/g for M. spicatum.

Formation of uniform and square nanopore arrays on (100) InP surfaces by a two-step etching method.

Uniform and square single-crystal InP nanopore arrays have been successfully fabricated on a (100) n-InP surface by a two-step etching method. The characteristic of slow etching rates in four equivalent crystalline (011) facets of (100) n-InP in a mixture of pure HCl and pure H(3)PO(4) has been found, which is the main reason for the formation of square single-crystal InP nanopores. The distribution of nanopores can be closely associated with the distribution of carriers in the semiconductor during the electrochemical etching process. An oscillating behaviour of current has been observed, which can probably be attributed to the oscillations in concentration of the electrolyte at the pore tips caused by diffusion of the electrolyte in the nanopore channels.

Equilibrium and kinetics of copper(II) biosorption by Myriophyllum spicatum L.

The potential use of Myriophyllum spicatum L. biomass as a biosorbent for the removal of copper(II) from aqueous solution was investigated in laboratory condition. The sorption experiments were undertaken to obtain copper(II) biosorption properties of M. spicatum L., i.e. equilibrium time, the maximum capacity, and rate constants. Copper(II) biosorption was fast and equilibrium was attained within 35 min at initial copper(II) concentration of 6 mg/L. Different isotherm models including the Langmuir, Freundlich, Temkin and Redlich-Peterson model, were used to investigate the sorption capacity and isotherm. These models showed an excellent match with the experimental data except for the Freundlich model. According to the Langmuir coefficients, the maximum sorption capacity of copper onto M. spicatum L. was 10.80 mg/g. The kinetics of copper(II) sorption was also analysed and rate constants were derived. It was found that the overall sorption process was best described by the pseudo second-order equation, and that intraparticle diffusion was not the rate determining step. The results of this study showed that M. spicatum L. can be considered as useful vehicles for the removal and recovery of copper(II) from aqueous solutions.

Alterations in the formation of lipopolysaccharide and membrane vesicles on the surface of Pseudomonas aeruginosa PAO1 under oxygen stress conditions.

It has been postulated that phenotypic variation in the relative expression of two chemically distinct types of lipopolysaccharide (LPS), a serotype-specific LPS (B-band) and a common antigen LPS (A-band) in Pseudomonas aeruginosa is an important mechanism enabling this opportunistic pathogen to alter its surface characteristics to mediate adhesion and to survive under extreme conditions. To further investigate this, the relative expression levels of the two distinct types of LPS in P. aeruginosa PAO1 were investigated with cells grown in a chemostat at different dissolved oxygen tensions (pO(2)). The A-band LPS was constitutively expressed as pO(2) was increased from nearly zero to 350 % of air saturation. In contrast, the B-band LPS showed a remarkable increase with increased pO(2). Almost no B-band LPS was found in cells grown at a pO(2) of less than 3 % of air saturation. Electron microscopic examination of cells revealed increased formation of membrane vesicles (MVs) on the surface of P. aeruginosa PAO1 under oxygen stress conditions. The toxicity of the supernatant of P. aeruginosa cultures to the growth of a hybridoma cell line significantly increased in samples taken from oxygen-stressed steady-state cultures. Furthermore, studies of adhesion in a continuous-flow biofilm culture revealed an increased adhesiveness for hydrophilic surfaces in P. aeruginosa PAO1 grown at a higher pO(2). The oxygen-dependent alterations of cell-surface components and properties observed in this work provide a possible explanation for the emergence of P. aeruginosa lacking the B-band LPS in chronically infected cystic fibrosis patients. The results are also useful for understanding the processes involved in the formation of MVs in P. aeruginosa.