122 research outputs found
IroN, a Novel Outer Membrane Siderophore Receptor Characteristic of Salmonella enterica
Speciation in enterobacteria involved horizontal gene transfer. Therefore, analysis of genes acquired by horizontal transfer that are present in one species but not its close relatives is expected to give insights into how new bacterial species were formed. In this study we characterize iroN, a gene located downstream of the iroBC operon in the iroA locus of Salmonella enterica serotype Typhi. Like iroBC, the iroN gene is present in all phylogenetic lineages of S. enterica but is absent from closely related species such as Salmonella bongori or Escherichia coli. Comparison of the deduced amino acid sequence of iroN with other proteins suggested that this gene encodes an outer membrane siderophore receptor protein. Mutational analysis in S. enterica and expression in E. coli identified a 78-kDa outer membrane protein as the iroN gene product. When introduced into an E. coli fepA cir fiu aroB mutant on a cosmid, iroN mediated utilization of structurally related catecholate siderophores, including N-(2,3-dihydroxybenzoyl)-l-serine, myxochelin A, benzaldehyde-2,3-dihydroxybenzhydrazone, 2-N,6-N-bis(2,3-dihydroxybenzoyl)-l-lysine, 2-N,6-N-bis(2,3-dihydroxybenzoyl)-l-lysine amide, and enterochelin. These results suggest that the iroA locus functions in iron acquisition in S. enterica
Luminescence spectroscopy of singlet oxygen enables monitoring of oxygen consumption in biological systems consisting of fatty acids
The interaction of singlet oxygen (1O2) generated in a photosensitized process with well-known reference photosensitizers Perinaphthenone (PN) and TMPyP is investigated in a model system consisting of fatty acids and the respective exogenous photosensitizer (PS) in solution by direct detection of the luminescence photons of 1O2 at 1270 nm. Such a model system is a first approach to mimic the complex environment of 1O2 in a biological cell which consists mainly of water, proteins, sugars and lipids. Firstly, the important issue of oxygen consumption is evaluated which has to be considered during luminescence detection of 1O2. It is known that the luminescence signal of 1O2 is dependent on the oxygen concentration of the environment. Cellular components such as lipids represent oxygen consumers due to peroxidation of their unsaturated double bonds. Secondly, the experimental conditions for this model system regarding oxygen consumption are optimized to estimate the rates and rate constants of the coupled system. Thirdly, the triplet decay of the PS can provide more precise information about the actual oxygen concentration close to the PS and can be used, therefore, as a more precise method to determine the oxygen concentration in more complex systems such as a biological cell. The aim is to get a better understanding of photosensitized reactions of 1O2 with cellular components to further improve methodologies, in particular at a cellular level using luminescence spectroscopy. In conclusion, luminescence detection might be a helpful tool to monitor precisely and promptly changes in oxygen concentration in a complex environment
Phototherapy: Theory and practice
Despite the development of highly effective biologics for skin diseases such as psoriasis or atopic dermatitis, UVA and UVB therapy, alone or in combination, are still essential components of various guidelines. Phototherapy is not only a first-line treatment and highly effective for a number of skin diseases, but is also economical and has few side effects. The targeted use of UVA and UVB, if necessary, in combination with the photosensitizer psoralen in the context of PUVA therapy, enables the dermatologist to effectively treat a wide variety of skin diseases. Indications for phototherapy include epidermal diseases such as atopic dermatitis, psoriasis and vitiligo, as well as photodermatoses, mycosis fungoides, graft-versus-host disease and deep dermal diseases such as scleroderma. This article reviews the physical principles, molecular mechanisms, current treatment regimens, and individual indications for phototherapy and photochemotherapy
Zur Problematik der pleistozĂ€nen und holozĂ€nen Vergletschernung SĂŒd-Kamtschatkas â erste Ergebnisse bodengeographischer Untersuchungen
Im Plotnikovagebiet westlich von Petropavlovsk,SĂŒd-Kamtschatka, lassen sich mindestens zwei TalmorĂ€nenkomplexe (M1 und M2) mit dazugehörigen Terrassensystemen nachweisen. Die Ă€lteren sogenannten M1-MorĂ€nen reichen bis auf ca. 300 m uÌ. M. herab; sie haben weiche, verwaschene Konturen. Die jĂŒngeren M2-MorĂ€nen schlieĂen sich ab etwa 350 - 450 m an; ihr Relief ist unruhig, reich an Toteislöchern und Wallformen. Die Böden dieser MorĂ€nen und der korrespondierenden T1- bzw. T2-Terrassen unterscheiden sich bezĂŒglich Verwitterung und Verbraunung nur geringfĂŒgig. So weisen die M1- bzw. T1-Böden krĂ€ftigere Kryoturbationen auf sowie deutlichere Verwitterungsrinden am Bodenskelett. Jedoch fehlen Hinweise auf eine interglaziale ĂberprĂ€gung z. B. In Form tonreicher Unterbodenhorizonte. Alle Böden weisen auĂerdem 3-4 Tephralagen auf, die auf folgende Eruptionen zurĂŒckgefĂŒhrt werden können: Tephra 1 = Opala, 1400-1500 a BP; Tephra 2 = Ksudach 1, 1700-1800 a BP; Tephra 3 = Ksudach 2 = 6000 a BP; Tephra 4 = Kuril Lake Il'inskay, 7600-7700 a BP (BRAITSEVA et al. 1992). Wir nehmen deshalb an, daĂ die M1-MorĂ€nen nicht ins MittelpleistozĂ€n, sondern ins SpĂ€tpleistozĂ€n einzuordnen sind, und kein Interglazial sie von den M2-MorĂ€nen trennt. Vielmehr lassen die Befunde vermuten, daĂ die M1-MorĂ€nen wĂ€hrend einer frĂŒhen Phase des SpĂ€tpleistozĂ€ns, die M2-MorĂ€nen wĂ€hrend einer spĂ€teren Periode des SpĂ€tpleistozĂ€ns abgelagert wurden. Dieses Ergebnis macht wahrscheinlich, daĂ in Kamtschatka, im Gegensatz zu Mitteleuropa, die Gletscher in einer frĂŒheren Phase des SpĂ€tpleistozĂ€ns (vergleichbar dem FrĂŒhwĂŒrm) weiter ins Tal vorgestoĂen sind, als wĂ€hrend der spĂ€ter folgenden Perioden. Tephrachronologische Untersuchungen einer Bodensequenz auf StirnmorĂ€nen von 350-1000 m ĂŒ. M. im Topolovajatal ergeben, daĂ diese bis ca. 930 m ĂŒ. M. stets Tephra 1, 2, 3 und 4 aufweisen und damit Ă€lter als 7600/7700 Jahre BP sind, also zu hoch- und spĂ€tglazialen, evtl. auch frĂŒhholozĂ€nen GletschervorstöĂen gehören. Erst die StirnmorĂ€nen in ca. 980 m zeigen lediglich Tephra 1 und 2; sie sind somit Ă€lter als 1700/1800 Jahre BP, aber jĂŒnger als 6000 Jahre BP. Vermutlich korrelieren sie mit mittelholozĂ€nen EisvorstöĂen. In ca. 1000 m Höhe liegen zwei weitere frische WallmorĂ€nen mit initialer Bodenbildung, die nach den lichenometrischen Befunden wĂ€hrend der sog. âkleinen Eiszeit" gebildet wurden. Tephralagen treten nicht mehr auf.researc
Salmonella typhimurium IroN and FepA Proteins Mediate Uptake of Enterobactin but Differ in Their Specificity for Other Siderophores
Antimicrobial coatings for environmental surfaces in hospitals: a potential new pillar for prevention strategies in hygiene
Recent reports provide evidence that contaminated healthcare environments represent major sources for the acquisition and transmission of pathogens. Antimicrobial coatings (AMC) may permanently and autonomously reduce the contamination of such environmental surfaces complementing standard hygiene procedures. This review provides an overview of the current status of AMC and the demands to enable a rational application of AMC in health care settings. Firstly, a suitable laboratory test norm is required that adequately quantifies the efficacy of AMC. In particular, the frequently used wet testing (e.g. ISO 22196) must be replaced by testing under realistic, dry surface conditions. Secondly, field studies should be mandatory to provide evidence for antimicrobial efficacy under real-life conditions. The antimicrobial efficacy should be correlated to the rate of nosocomial transmission at least. Thirdly, the respective AMC technology should not add additional bacterial resistance development induced by the biocidal agents and co- or cross-resistance with antibiotic substances. Lastly, the biocidal substances used in AMC should be safe for humans and the environment. These measures should help to achieve a broader acceptance for AMC in healthcare settings and beyond. Technologies like the photodynamic approach already fulfil most of these AMC requirements
Adverse Reactions after Tattooing: Review of the Literature and Comparison to Results of a Survey
The number of tattooed people has substantially increased in the past years. Surveys in different countries reveal this to be up to 24% of the population. The number of reported adverse reactions after tattooing has also increased including infections, granulomatous and allergic reactions and tumors. However, the case reports do not reflect the frequency of adverse reactions. This review compares the medically documented adverse reactions published in 1991-2011 with the findings of a nation-wide survey that recently revealed the features and health problems associated with tattoos. To compare the data with the survey, the sex of patients was reported and the location and color of tattoos were evaluated. The results show clearly that colored tattoo inks are mainly responsible for adverse skin reactions and that tattoos on the extremities are involved most
Bodengeographische Beobachtungen zur pleistozÀnen und holozÀnen Vergletscherung des Westlichen Tienshan (Usbekistan)
Im Oigaing-Tal zwischen Ugamsky- und Pskemsky-Gebirge nordöstlich von Taschkent (West-Tienshan, Usbekistan) wurden bodengeographische Untersuchungen zur pleistozĂ€nen und holozĂ€nen Vergletscherung durchgefĂŒhlt. Eindeutige EndmorĂ€nen der letzten Hauptvergletscherung konnten im Bereich des Zusammenflusses von Maidan und Oigaing in 1500 - 1600 m ĂŒ. M. nachgewiesen werden mit mĂ€chtigen, bis in 80 cm Tiefe tiefgrĂŒndig verwitterten Bodenbildungen. Vergleichbare Ablagerungen vermutlich hochglazialer bzw. spĂ€tglazialer Genese finden sieh auch talaufwĂ€rts im MĂŒndungsbereich zahlreicher SeitentĂ€ler (Beschtor-, Tekesch-, AĂŒtor-Tal) in das Oigaing-Haupttal. Die SeitentĂ€ler weisen in 2500 bis 2700 m spĂ€tglaziale Stirn- und GrundmorĂ€nen auf. Die Böden dieser Ablagerungen sind ebenfalls bis in 40 - 60 cm Tiefe stark verwittert und verbraunt. Den rezenten Gletschern, die bis auf ca. 3000 - 3200 m herabreichen, sind weitere MorĂ€nen holozĂ€nen bzw. neuzeitlichen Ursprungs vorgelagert mit flachgrĂŒndigen, z. T. initialen Bodenbildungcn, die vermutlich mit GletschervorstöĂen wĂ€hrend der sogenannten âKleinen Eiszeit" mit einem Maximum in den Alpen um 1850 und im mittleren HolozĂ€n um 2000 bzw. 4000 a BP ĂŒbereinstimmen. Im unteren Seitental des Barkrak sind oberhalb von hochglazialen Eisrandlagen O2850 m) interglaziale, sehr stark verwitterte und rubefizierte Bodenbildungen aus altquartĂ€ren Schottern erhalten, die von einer spĂ€tpleistozĂ€nen Solifluktionsdecke ĂŒberfahren wurden. Der obere Talverlauf ist dagegen oberhalb dieser hochglazialen Eisrandleisten durch mĂ€chtige Geschiebe gekennzeichnet. Sie sind Zeugen Ă€lterer, im Vergleich zur jĂŒngsten Hauptvergletscherung wesentlich mĂ€chtigerer Vereisungen. Die dazugehörigen MorĂ€nen konnten jedoch nicht gefunden werden.researc
UVA and endogenous photosensitizers â the detection of singlet oxygen by its luminescence
UVA irradiation (320â400 nm) comprises about 95 percent of incident midday solar ultraviolet irradiation. It penetrates skin much deeper than UVB irradiation. The absorption of UVA irradiation in endogenous chromophores frequently leads to the generation of reactive oxygen species such as singlet oxygen (1O2). 1O2 is an important biochemical intermediate in multiple biological processes. Beside other procedures, the direct detection of 1O2 by its luminescence is a powerful tool that helps to understand the generation of 1O2 during UVA exposure in solution, in vitro and in vivo. This article describes the endogenous photosensitizers, their ability to generate 1O2 under UVA irradiation, and the detection technology to visualize the action of 1O2
Utilizing 5-aminolevulinic acid and pulsed dye laser for photodynamic therapy of oral leukoplakia â pilot study
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