"Prion-like" seeding and propagation of oligomeric protein assemblies in neurodegenerative disorders.

Intra- or extracellular aggregates of proteins are central pathogenic features in most neurodegenerative disorders. The accumulation of such proteins in diseased brains is believed to be the end-stage of a stepwise aggregation of misfolded monomers to insoluble cross-β fibrils via a series of differently sized soluble oligomers/protofibrils. Several studies have shown how α-synuclein, amyloid-β, tau and other amyloidogenic proteins can act as nucleating particles and thereby share properties with misfolded forms, or strains, of the prion protein.

Cryptic species and hidden ecological interactions of halictine bees along an elevational gradient.

Changes of abiotic and biotic conditions along elevational gradients represent serious challenges to organisms which may promote the turnover of species, traits and biotic interaction partners. Here, we used molecular methods to study cuticular hydrocarbon (CHC) profiles, biotic interactions and phylogenetic relationships of halictid bees of the genus along a 2,900 m elevational gradient at Mt. Kilimanjaro, Tanzania.

Linking pollen foraging of megachilid bees to their nest bacterial microbiota.

Unlabelled: Solitary bees build their nests by modifying the interior of natural cavities, and they provision them with food by importing collected pollen. As a result, the microbiota of the solitary bee nests may be highly dependent on introduced materials. In order to investigate how the collected pollen is associated with the nest microbiota, we used metabarcoding of the ITS2 rDNA and the 16S rDNA to simultaneously characterize the pollen composition and the bacterial communities of 100 solitary bee nest chambers belonging to seven megachilid species.

Bacterial community structure and succession in nests of two megachilid bee genera.

Studies on honeybees have revealed bacterial taxa which adopt key functions in the hive, in terms of nutrient uptake and immune responses. Despite solitary bees providing invaluable ecological services, the contribution of their microbial communities to larval health and the development and fitness of adults is mainly unknown. To address this gap, we conducted a 16S rDNA meta-barcoding study including larvae and stored pollen in nest chambers from two different megachilid solitary bee genera.

Effects of Resveratrol Supplementation in Nrf2 and NF-κB Expressions in Nondialyzed Chronic Kidney Disease Patients: A Randomized, Double-Blind, Placebo-Controlled, Crossover Clinical Trial.

Introduction: Resveratrol is a phenolic compound that has demonstrated anti-inflammatory and antioxidant effects, resulting from enhanced antioxidant enzymes production and modulating nuclear factors involved in the inflammation-oxidative stress cycle, as nuclear erythroid 2-related factor 2 (Nrf2) and nuclear factor-κB (NF-κB).

Objective: The study aim was to evaluate the effects of resveratrol supplementation on Nrf2 and NF-κB expression in nondialyzed chronic kidney disease (CKD) patients.

Materials And Methods: A randomized, double-blind, crossover trial was performed in 20 nondialyzed CKD patients (62.

Increased efficiency in identifying mixed pollen samples by meta-barcoding with a dual-indexing approach.

Background: Meta-barcoding of mixed pollen samples constitutes a suitable alternative to conventional pollen identification via light microscopy. Current approaches however have limitations in practicability due to low sample throughput and/or inefficient processing methods, e.g.

Evaluating multiplexed next-generation sequencing as a method in palynology for mixed pollen samples.

The identification of pollen plays an important role in ecology, palaeo-climatology, honey quality control and other areas. Currently, expert knowledge and reference collections are essential to identify pollen origin through light microscopy. Pollen identification through molecular sequencing and DNA barcoding has been proposed as an alternative approach, but the assessment of mixed pollen samples originating from multiple plant species is still a tedious and error-prone task.

Diverse microbiota identified in whole intact nest chambers of the red mason bee Osmia bicornis (Linnaeus 1758).

Microbial activity is known to have profound impact on bee ecology and physiology, both by beneficial and pathogenic effects. Most information about such associations is available for colony-building organisms, and especially the honey bee. There, active manipulations through worker bees result in a restricted diversity of microbes present within the colony environment.

Mayaro virus infection in amazonia: a multimodel inference approach to risk factor assessment.

Background: Arboviral diseases are major global public health threats. Yet, our understanding of infection risk factors is, with a few exceptions, considerably limited. A crucial shortcoming is the widespread use of analytical methods generally not suited for observational data--particularly null hypothesis-testing (NHT) and step-wise regression (SWR).

Evidence of a novel immune responsive protein in the Hymenoptera.

Honeybee populations are severely threatened by parasites and diseases. Recent outbreaks of Colony Collapse Disorder (CCD) has caused loss of more than 35% of bee colonies in the USA, and this is thought to at least in part be due to parasites and/or disease. Interestingly, the honeybee possesses of a limited set of immune genes compared to other insects.

Detection of carcinogenic aromatic amines in the urine of non-smokers.

Smoking is thought to be one of the most important anthropogenic risk factors involved in the development of urinary bladder cancer in humans. Tobacco smoke contains a complex mixture of chemicals including potent carcinogens such as aromatic amines. In the present study the amounts of several freebase aromatic amines including the potent carcinogens 2-aminonaphthalene and 4-aminobiphenyl have been analyzed in the urine of 48 German urban living smokers and non-smokers.

Profile of urinary phenanthrene metabolites in smokers and non-smokers.

Phenanthrene metabolites (phenols and dihydrodiols) and 1-hydroxypyrene excreted in the 24-h urine of smokers, non-smokers and lung cancer patients, who after heavy smoking became light smokers, were determined and compared. In contrast to 1- hydroxypyrene, no significant differences of the absolute amounts of phenanthrene metabolites were found between smokers and non-smokers. A ratio phenanthrene metabolites/l-hydroxypyrene of 10.

Regio- and stereoselectivity in the metabolism of benzo[c]phenanthrene mediated by genetically engineered V79 Chinese hamster cells expressing rat and human cytochromes P450.

Regio- and stereoselective metabolism mediated by cytochrome P450 (CYP) and metabolite-dependent cytotoxicity of benzo[c]phenanthrene (B[c]Ph) and its trans-3,4-dihydrodiol, the metabolic precursor of the carcinogenic fjord-region B[c]Ph-3,4-dihydrodiol 1,2-epoxides (B[c]PhDE), were investigated with V79 Chinese hamster cells genetically engineered for three rat and six human CYP isoforms. The order of the capabilities of the CYP isoforms to metabolize B[c]Ph was as follows: h1A1>r1A1>r1A2>h1B1>h1A2>r2B1>>h2E1>h2A6>h3A4. Regardless of the species, all individual CYP isoforms preferentially catalyzed the oxidation of B[c]Ph at the 5,6-position (K-region) except human CYP1A1 and human CYP1A2, which oxidized both the 5,6- and the 3,4-position with similar efficiency.

Environmental monitoring and banking of marine pollutants by using common mussels.

Since 1985 the common mussel Mytulis edulis has been collected, characterized and stored within the framework of the German Environmental Specimen Bank program. Selected results about the determination of various pollutants such as heavy metals, polycyclic aromatic hydrocarbons and chlorinated hydrocarbons are presented. Particular emphasis is given to the comparison of seasonal variations with respect to different environmental contaminants and their correlations depending on sampling location and time.

Long-term decline of atmospheric and marine pollution by polycyclic aromatic hydrocarbons (PAHS) in Germany.

Concentrations of benzo[a]pyrene and benzo[e]pyrene in the atmosphere as markers for the class of PAHs decreased by about 70% within one decade in clean air as well as in industrially polluted areas of Germany when measured with passive samplers (spruce sprouts, poplar and beech leaves). The same trend has been found for East-Germany during 1991-1995. Mussels (Mytilus edulis) were found to accumulate PAHs from the aquatic environment and exhibited a seasonal periodicity of the PAH concentration.

DNA single strand breakage, DNA adducts, and sister chromatid exchange in lymphocytes and phenanthrene and pyrene metabolites in urine of coke oven workers.

Objectives: To investigate the specificity of biological monitoring variables (excretion of phenanthrene and pyrene metabolites in urine) and the usefulness of some biomarkers of effect (alkaline filter elution, 32P postlabelling assay, measurement of sister chromatid exchange) in workers exposed to polycyclic aromatic hydrocarbons (PAHs).

Methods: 29 coke oven workers and a standardised control group were investigated for frequencies of DNA single strand breakage, DNA protein cross links (alkaline filter elution assay), sister chromatid exchange, and DNA adducts (32P postlabelling assay) in lymphocytes. Phenanthrene and pyrene metabolites were measured in 24 hour urine samples.

Determination of urinary metabolites of polycyclic aromatic hydrocarbons (PAH) for the risk assessment of PAH-exposed workers.

A method for the simultaneous determination of urinary phenanthrene, fluoranthene, pyrene, chrysene and benzo[a]pyrene metabolites has been developed for individual risk assessment at polycyclic aromatic hydrocarbon (PAH)-burdened workplaces. The concentration of urinary metabolites as a measure for individual PAH exposure takes account not only of PAH masses resorbed by the respiratory tract but also those incorporated percutaneously. The method allows the determination of 25 different components with a low margin of error; the individual metabolite profiles thereby allow conclusions on the individual characteristics of PAH-oxidizing enzymes (monooxygenases).

Cytochrome P450-mediated activation of phenanthrene in genetically engineered V79 Chinese hamster cells.

V79 Chinese hamster cells genetically engineered for rat cytochromes P450 1A1, 1A2, 2B1 and human cytochromes P450 1A1, 1A2, 2A6, 2E1, and 3A4 are being applied in metabolism studies on polycyclic aromatic hydrocarbons. This study presents the results on phenanthrene as the prototypic polycyclic aromatic hydrocarbon possessing a bay region. Phenanthrene is of less importance regarding cytotoxicity and carcinogenicity as compared to e.

Metabolism and excretion of polycyclic aromatic hydrocarbons in rat and in human.

Polycyclic aromatic hydrocarbons have shown to be an important class of environmental and occupational carcinogens. By balancing the carcinogenic potential PAH were found to predominantly contribute to the biological activity of environmental matter such as vehicle exhaust, used motor oil, and hard-coal combustion effluents. Due to the individual ratio of toxifying and detoxifying processes PAH-exposure measurements are not appropriate to be used for risk assessment without any further information on their metabolic fate.

Urinary metabolite profile of PAH as a potential mirror of the genetic disposition for cancer.

Polycyclic aromatic compounds such as polycyclic aromatic hydrocarbons or aromatic amines presently are considerably underestimated with regard to the formation of environmentally caused cancer diseases. The individual urinary metabolite profile raising from the PAH inhaled is invariant. This holds for tar-pitch aerosol exposed Wistar rats as well as for PAH-exposed workers.

Covalent binding of polycyclic aromatic hydrocarbon components of coal tar to DNA in mouse skin.

Treatment of mouse skin with coal tar is known to initiate tumour formation, with the carcinogenic activity associated mainly with polycyclic aromatic hydrocarbons (PAHs). A sample of pharmaceutical coal tar was analysed by gas chromatography and 19 major PAHs were identified. 32P-postlabelling analysis was used to characterize those PAHs that are responsible for the DNA binding of coal tar and, by inference, its biological activity.

Biomonitoring of polycyclic aromatic hydrocarbons in highly exposed coke plant workers by measurement of urinary phenanthrene and pyrene metabolites (phenols and dihydrodiols).

A filter combination consisting of an impregnated glass fibre and a control filter was used for the collection of air samples in which gaseous and particulate polycyclic aromatic hydrocarbons (PAHs) were determined. To estimate the loss of lower boiling PAHs, d10-phenanthrene was applied as internal standard. A simple, well-producible method for the determination of 1-, 2-, 3-, 4- and 9-hydroxyphenanthrene, 1,2-, 3,4- and 9,10-dihydroxydihydrophenanthrene, 1-hydroxypyrene and 1,2-dihydroxy-1,2-dihydropyrene is described.