Epidemiological association of Campylobacter jejuni groups with pathogenicity-associated genetic markers

ABSTRACT: BACKGROUND: Campylobacter jejuni, the most leading cause for bacterial gastroenteritis worldwide, shows a high genetic diversity among its isolates. Recently, we demonstrated the existence of six C. jejuni-groups by combining MLST with six genetic markers. These groups were further characterized by the detection of cj1321-cj1326, fucP, cj0178, cj0755/cfrA, ceuE, pldA, cstII, and cstIII in order (I.) to show further associations between these different genetic markers and MLST CCs. Moreover, different studies were able to associate several of these markers: a sialylated lipoologosaccharide (cstII/III+), the gamma-glytamyl-transpeptidase (ggt+), and the absence of a certain allele of the enterochelin-uptake-binding-protein (ceuE11168-) with severe campylobacteriosis, bloody diarrhea and unpleasant outcome. Additionally more than half of human Campylobacter-isolates were assigned to a non-livestock clade associated with the absence of cj1321-cj1326. These isolates were considered as mere colonizers. From the combination of marker genes, the ratio of human isolates in a specific group, and clinical data (II.) it should be demonstrated to which of the previous defined groups these Campylobacter-subpopulations, associated with higher virulence, correspond. RESULTS: Besides the marker gene pldA, all new estimated genetic markers show significant differences in their distribution among the various MLST-based groups. Especially the genes for cj1321-cj1326, fucP, cj0178, cj0755/cfrA are widely associated with each other and split the study population into two major and seven intermediate groups substantiating the previous group-definition, whereas cstII and cstIII indicate at least three groups following an independent distribution pattern. CONCLUSIONS: Based on these data a group of C. jejuni-isolates characterized by the presence of ansB, dmsA, ggt, and the absence of cj1365c, cj1585c, cj1321-cj1326, fucP, cj0178, cj0755/cfrA, and cstII/III was associated with a higher prevalence in human campylobacteriosis, bloody diarrhea as well as hospitalization and bears obviously a higher virulence for humans. In contrast to that better livestock-adapted groups characterized by the ability to utilize L-fucose and the presence of all of the ve identied putative C. jejuni iron-uptake systems as well as cj1321-cj1326, cj1365c, cj1585c, and cstII and/or cstIII (sialylated lipoologosaccharide) is more prevalent in animal hosts and was secondary associated with less severe campylobacteriosis.     

Design of Carbon Nanotube‐Based Gas‐Diffusion Cathode for O2 Reduction by Multicopper Oxidases

Multicopper oxidases, such as laccase or bilirubin oxidase, are known to reduce molecular oxygen at very high redox potentials, which makes them attractive biocatalysts for enzymatic cathodes in biological fuel cells. By designing an enzymatic gas‐diffusion electrode, molecular oxygen can be supplied through the gaseous phase, avoiding solubility and diffusion limitations typically associated with liquid electrolytes. In doing so, the current density of enzymatic cathodes can theoretically be enhanced. This publication presents a material study of carbon/Teflon composites that aim to optimize the functionality of the gas‐diffusion and catalytic layers for application in enzymatic systems. The modification of the catalytic layer with multiwalled carbon nanotubes, for example, creates the basis for stronger π–π stacking interactions through tethered enzymatic linkers, such as pyrenes or perylene derivates. Cyclic voltammograms show the effective direct electron contact of laccase with carbon nanotube‐modified electrodes via tethered crosslinking molecules as a model system. The polarization behavior of laccase‐modified gas‐diffusion electrodes reveals open‐circuit potentials of +550 mV (versus Ag/AgCl) and current densities approaching 0.5 mA cm² (at zero potential) in air‐breathing mode.     

Furan in heat-treated foods: Formation, exposure, toxicity, and aspects of risk assessment

Furan is formed in a variety of heat-treated foods through thermal degradation of natural food constituents. Relatively high levels of furan contamination are found in ground roasted coffee, instant coffee, and processed baby foods. European exposure estimates suggest that mean dietary exposure to furan may be as high as 1.23 and 1.01 μg/kg bw/day for adults and 3- to 12-month-old infants, respectively. Furan is a potent hepatotoxin and hepatocarcinogen in rodents, causing hepatocellular adenomas and carcinomas in rats and mice, and high incidences of cholangiocarcinomas in rats at doses ≥2 mg/kg bw. There is therefore a relatively low margin of exposure between estimated human exposure and doses that cause a high tumor incidence in rodents. Since a genotoxic mode of action cannot be excluded for furan-induced tumor formation, the present exposures may indicate a risk to human health and need for mitigation. This review summarizes the current knowledge on mechanisms of furan formation in food, human dietary exposure to furan, and furan toxicity, and highlights the need to establish the risk resulting from the genotoxic and carcinogenic properties of furan at doses lower than 2 mg/kg bw.     

Unconventional secretion of fibroblast growth factor 2 and galectin-1 does not require shedding of plasma membrane-derived vesicles

Various molecular mechanisms of unconventional secretion of fibroblast growth factor 2 and galectin-1 have been proposed. A non-vesicular pathway that is based on direct translocation across the plasma membrane has been described. In other studies, however, release into the extracellular space of cell-derived vesicles was implicated in both FGF-2 and Gal-1 secretion. Such vesicles were proposed to originate either from plasma membrane shedding or by the release of exosomes. Employing an inhibitor of plasma membrane blebbing and based on a quantitative biochemical analysis of cell culture supernatants for vesicles potentially carrying FGF-2 or Gal-1, we demonstrate that both FGF-2 and Gal-1 are not exported by shedding of plasma membrane-derived vesicles.     

Oxidative damage of albumin in advanced liver disease

Albumin has a number of biological functions and the serum albumin level is related to prognosis in advanced liver disease. Oxidative stress is believed to play an important role in the pathogenesis of liver failure. The aim of the present study was to characterize oxidative modification of albumin in patients with various degrees of liver failure and to investigate implications for its binding function. Patients with liver cirrhosis (n=10), acute-on-chronic liver failure (n=8) and healthy controls (n=15) were included in the study. Three fractions of albumin were separated by HPLC according to the redox state of cysteine-34 and detected by fluorescence as well as UV absorption. Carbonyl groups were measured as a marker of oxidative modification in plasma proteins and, by western blotting, on albumin. Progressive oxidative modification of albumin was found with increasing severity of liver failure indicated by an increased content of carbonyl groups and oxidation of cysteine-34. Fluorescence properties of albumin were altered by oxidation and, in patients with acute-on-chronic liver failure, by high plasma levels of bilirubin. This alteration of albumin fluorescence by bilirubin provides evidence for a preferred binding of bilirubin to the fully reduced form of albumin.     

The Internet as a Mental Health Advisor in Germany—Results of a National Survey

The internet constitutes a popular source of health information. However, the use of the internet and other modern media in the domain of mental health remains widely unclear. This study aimed at exploring the readiness for seeking information online and making use of online counseling and media-assisted psychotherapy. A representative survey of N = 2411 Germans was conducted. Results indicated that more than one fourth of Germans would consider seeking help online in case of psychic strain. Participants reported that they would use the internet when needing to research about mental health topics and to communicate with persons concerned on internet forums. Only a small number of participants had already used psychological online-counseling. The majority of subjects reported not having known about the possibility of online counseling. However, the willingness to make use of this option in the future was in a medium range. Concerning the treatment of mental disorders, participants showed a clear preference toward conventional face-to-face treatment. Less than 10% of participants considered the use of treatment supported by mobile phones, the internet, or virtual realities as likely. Certainly, readiness was significantly higher in persons who were already using the relevant devices—mobile phones, computers, and the internet. In the future, there will presumably be an increasing demand for media-assisted psychological counseling and interventions. Members of the health care system should therefore prepare for current developments and help enlighten patients with regard to the possibilities, and also the potential risks of e-mental health.     

Osteopontin Is Induced by TGF-β2 and Regulates Metabolic Cell Activity in Cultured Human Optic Nerve Head Astrocytes

The aqueous humor (AH) component transforming growth factor (TGF)-β2 is strongly correlated to primary open-angle glaucoma (POAG), and was shown to up-regulate glaucoma-associated extracellular matrix (ECM) components, members of the ECM degradation system and heat shock proteins (HSP) in primary ocular cells. Here we present osteopontin (OPN) as a new TGF-β2 responsive factor in cultured human optic nerve head (ONH) astrocytes. Activation was initially demonstrated by Oligo GEArray microarray and confirmed by semiquantitative (sq) RT-PCR, realtime RT-PCR and western blot. Expressions of most prevalent OPN receptors CD44 and integrin receptor subunits αV, α4, α 5, α6, α9, β1, β3 and β5 by ONH astrocytes were shown by sqRT-PCR and immunofluorescence labeling. TGF-β2 treatment did not affect their expression levels. OPN did not regulate gene expression of described TGF-β2 targets shown by sqRT-PCR. In MTS-assays, OPN had a time- and dose-dependent stimulating effect on the metabolic activity of ONH astrocytes, whereas TGF-β2 significantly reduced metabolism. OPN signaling via CD44 mediated a repressive outcome on metabolic activity, whereas signaling via integrin receptors resulted in a pro-metabolic effect. In summary, our findings characterize OPN as a TGF-β2 responsive factor that is not involved in TGF-β2 mediated ECM and HSP modulation, but affects the metabolic activity of astrocytes. A potential involvement in a protective response to TGF-β2 triggered damage is indicated, but requires further investigation.     

Brassinosteroids Dominate Hormonal Regulation of Plant Thermomorphogenesis via BZR1

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