The locus of enterocyte effacement (LEE)-encoded regulator controls expression of both LEE- and non-LEE-encoded virulence factors in enteropathogenic and enterohemorrhagic Escherichia coli

Regulation of virulence gene expression in enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) is incompletely understood. In EPEC, the plasmid-encoded regulator Per is required for maximal expression of proteins encoded on the locus of enterocyte effacement (LEE), and a LEE-encoded regulator (Ler) is part of the Per-mediated regulatory cascade upregulating the LEE2, LEE3, and LEE4 promoters. We now report that Ler is essential for the expression of multiple LEE-located genes in both EPEC and EHEC, including those encoding the type III secretion pathway, the secreted Esp proteins, Tir, and intimin. Ler is therefore central to the process of attaching and effacing (AE) lesion formation. Ler also regulates the expression of LEE-located genes not required for AE-lesion formation, including rorf2, orf10, rorf10, orf19, and espF, indicating that Ler regulates additional virulence properties. In addition, Ler regulates the expression of proteins encoded outside the LEE that are not essential for AE lesion formation, including TagA in EHEC and EspC in EPEC. delta ler mutants of both EPEC and EHEC show altered adherence to epithelial cells and express novel fimbriae. Ler is therefore a global regulator of virulence gene expression in EPEC and EHEC.     

Energy metabolism of the contagious equine metritis bacterium.

The energy metabolism of the English E-CMO strain of contagious equine metritis bacterium was studied in whole cells and cell extracts. This bacterium appears to have an active Krebs cycle and probably obtains energy by oxidative phosphorylation since glycolysis and the hexose monophosphate pathways appear to be absent. These conclusions are based on the findings that [U-14C]glucose incorporation by this bacterium is below the level of detection, and that respiration is stimulated by Krebs cycle intermediates (i.e., malate, citrate, and succinate), but not by glucose, fructose, maltose, or sucrose. Furthermore, support comes from the fact that enzymes generally associated with the Krebs cycle and electron transport (i.e., malate dehydrogenase, succinate dehydrogenase, isocitrate dehydrogenase, fumarate hydratase, malate dehydrogenase [decarboxylating], cytochrome oxidase, superoxide dismutase, NADH dehydrogenase, and catalase) were detected. Those enzymes normally associated with glycolysis and the hexose monophosphate pathways (i.e., hexokinase, glucose 6-phosphate dehydrogenase, fructose biphosphate aldolase, glycerol 3-phosphate dehydrogenase, phosphoenolpyruvate carboxykinase, pyruvate kinase, phosphate acetyl transferase, acetate kinase, alcohol dehydrogenase, and lactate dehydrogenase) were below the level of detection.     

Use of the Roche LightCycler instrument in a real-time PCR for Trichomonas vaginalis in urine samples from females and males

Trichomonas vaginalis is the agent of a highly prevalent sexually transmitted infection (STI) that can result in vaginitis, urethritis, and preterm birth. Traditional methods of diagnosis, including wet preparation, can be unreliable. In this study, we describe the adaptation of an existing PCR method for specific detection of T. vaginalis DNA into a rapid real-time PCR assay based on fluorescence resonance energy transfer (FRET) probe chemistry. The FRET-based assay described demonstrated high sensitivity with a detection limit of 1.06 organisms, as well as a high specificity. A total of 253 urine samples collected prospectively from both men and women were tested for T. vaginalis DNA with both the FRET-based assay and a previously validated PCR assay. When the validated PCR assay was used as the "gold standard" and after discrepancies had been resolved, our FRET-based assay demonstrated an analytical sensitivity and specificity of 90.1 and 100%, respectively. Overall results suggest that FRET-based assays can provide rapid, accurate, and high-throughput detection of T. vaginalis and may prove useful in clinical settings and for large-scale screening programs.     

Effects of behavior modification on body image, depression and body fat in obese Korean elementary school children

This study was performed to investigate the effects of behavior modification on body image, depression and body fat in obese elementary school children. Sixty-two elementary students of the 4th to 6th grade were selected from two different Seoul schools. Thirty-four children in one school were designated as the experimental group, and 28 children from the other school as the control group. The experimental group received 60 - 70 minutes of behavior modification, once a week, for 8 weeks. The control group received neither management nor treatment. The results indicated a significant improvement of body image and a reduction in the increase rate of body fat for the experimental group. This finding strongly supports the theory that behavior modification can be used as an effective strategy in the treatment of obese children.     

Feline CD 4 molecules expressed on feline non-lymphoid cell lines are not enough for productive infection of highly lymphotropic feline immunodeficiency virus isolates

Summary To investigate whether the feline CD 4 (fCD 4) molecules are involved in infections of highly lymphotropic feline immunodeficiency virus (FIV) isolates, we expressed fCD 4 stably on Crandell feline kidney cells andFelis catus whole foetus 4 cells by transfection of a cDNA encoding the fCD 4 glycoprotein, and then infected them with TM 1 and TM 2 strains of FIV, which are unable to infect these cells productively. In spite of fCD 4 being expressed on these cells, no virus production was observed. This result indicates that fCD 4 expression alone cannot induce a productive infection of the FIV TM 1 and TM 2 strains.     

Epithelial cell polarity affects susceptibility to Pseudomonas aeruginosa invasion and cytotoxicity.

Intact tissues are relatively resistant to Pseudomonas aeruginosa-induced disease, and injury predisposes tissue to infection. Intact epithelia contain polarized cells that have distinct apical and basolateral membranes with unique lipids and proteins. In this study, the role of cell polarity in epithelial cell susceptibility to P. aeruginosa virulence mechanisms was tested. Madin-Darby canine kidney (MDCK) cells, human corneal epithelial cells, and primary cultures of two different types of airway epithelial cells were grown on Transwell filters or in plastic tissue culture wells. P. aeruginosa invasion of cells was quantified by gentamicin survival assays with two isolates that invade epithelial cells (6294 and PAO1). Cytotoxic activity was assessed by trypan blue exclusion assays with two cytotoxic strains (6206 and PA103). Basolateral surfaces of cells were exposed by one of two methods: EGTA pretreatment of epithelial cells or growth of cells in low-calcium medium. Both methods of exposing basolateral membranes increased epithelial cell susceptibility to P. aeruginosa invasion and cytotoxicity. Migrating cells were also found to be more susceptible to P. aeruginosa invasion than confluent monolayers that had established membrane polarity. Monolayers of MDCK cells that had been selected for resistance to killing by concanavalin A were resistant to both cytotoxicity and invasion by P. aeruginosa because they were more efficiently polarized for their susceptibility to P. aeruginosa virulence factors than regular MDCK cells and not because they were defective in glycosylation. These results suggest that there are factors on the basolateral surfaces of epithelial cells that promote interaction with P. aeruginosa or that there are inhibitory factors on the apical cell surface. Thus, cell polarity of intact epithelia is likely to contribute to defense against P. aeruginosa infection.     

Nanoscale Analysis of Polymer Interfaces by Energy‐Filtering Transmission Electron Microscopy

Summary: Energy‐filtering transmission electron microscopy (EFTEM) was employed for the analysis of polymer‐polymer interfaces. To attain imaging and spectral analyses with a spatial resolution of 10 nm, problems arising in the EFTEM analysis for polymer specimens were investigated. Interfaces in poly(methyl methacrylate)/polystyrene‐co‐polyacrylonitrile random copolymer (PMMA/SAN) bilayer films annealed at different temperatures were analyzed by means of elemental mapping and Image‐EELS on EFTEM and the effect of the annealing temperature on the interfacial structures was also investigated.

     

Intellectual Functioning of Pediatric Patients with Chronic Kidney Disease: Results from the KNOW-Ped CKD

BackgroundChronic kidney disease (CKD) has a negative impact on growth and development in children and is a risk factor for neurocognitive impairment; however, there is limited research on the cognitive function of children and adolescents with CKD. This study therefore aimed to investigate the mean intelligence and risk factors for low intelligence in children and adolescents with CKD.MethodsEighty-one patients with CKD under 18 years old were included in the KoreaN cohort study for Outcomes in patients With Pediatric Chronic Kidney Disease (KNOW-Ped CKD). Participants completed either the Wechsler Intelligence Scale for Children (6–16 years), or Wechsler Adult Intelligence Scale (> 16 years).ResultsThe mean full-scale intelligence quotient (IQ) was 91 ± 19; 24.7% of participants scored a full-scale IQ below 80. Participants with a short stature (height Z scores < −1.88), failure to thrive (weight Z scores < −1.65), more severe CKD stage (≥ IIIb), longer duration of CKD (≥ 5 years), and those who were Medicare or Medicaid beneficiaries, had significantly lower mean full-scale IQs.ConclusionOn linear regression analysis, the association between the full-scale IQ, and longer duration of CKD and growth failure, remained significant after controlling for demographic and clinical variables. It is therefore necessary to investigate cognitive impairment in pediatric patients with CKD who exhibit growth failure or for a longer postmorbid period. It is believed that early interventions, such as kidney transplantation, will have a positive effect on IQ in children with CKD, as the disease negatively affects IQ due to poor glomerular filtration rate over time.Trial RegistrationClinicalTrials.gov Identifier: {"type":"clinical-trial","attrs":{"text":"NCT02165878","term_id":"NCT02165878"}}NCT02165878     

Favourable associations between the myosin heavy-chain and light-chain isoforms in human skeletal muscle

Histochemical and biochemical analyses were performed in order to examine the relationship between myosin light-chain (LC) isoforms and fibre-type distributions in whole human skeletal muscle. Muscle biopsies were obtained from the vastus lateralis muscle in six healthy men, and analysed for the relative area occupied by each fibre type (percentage of fibre type area) and the molar ratio of each LC isoform. The percentage of type I fibre area was positively correlated with the molar ratio of slow LC (LC1s and LC2s) to total LC. The regression line was located below the line of unity. Also, the ratio of percentage of type II fibre area to that of type II fibre area was positively correlated with the molar ratio of the fast alkali LC LC1f to fast alkali LCs LC1f and LC3f. These results support previous study, having shown that in human skeletal muscle some type I fibres express various amounts of fast LC in addition to slow LC and suggest that fast myosin heavy-chain HCII a is favourably associated with LC1f, whereas HCIIb is favourably associated with LC3f.