Molecular Engineering of “Click”‐Phospholes Towards Self‐Assembled Luminescent Soft Materials

Inspired by the self‐assembled bilayer structures of natural amphiphilic phospholipids, a new class of highly luminescent “click”‐phospholes with exocyclic alkynyl group at the phosphorus center is reported. These molecules can be easily functionalized with a self‐assembly group to generate neutral “phosphole‐lipids”. This novel approach retains the versatile reactivity of the phosphorus center, allowing further engineering of the photophysical and self‐assembly properties of the materials at a molecular level. The results of this study highlight the importance of being able to balance weak intermolecular interactions for controlling the self‐assembly properties of soft materials. Only molecules with the appropriate set of intermolecular arrangement/interactions show both organogel and liquid crystal mesophases with well‐ordered microstructures. Moreover, an efficient energy transfer of the luminescent materials is demonstrated and applied in the detection of organic solvent vapors.     

Magnetite Crystal Orientation in Magnetosome Chains

One‐dimensional magnetic nanostructures have magnetic properties superior to non‐organized materials due to strong uniaxial shape anisotropy. Magnetosome chains in magnetotactic bacteria represent a biological paradigm of such magnet, where magnetite crystals synthesized in organelles called magnetosomes are arranged into linear chains. Two‐dimensional synchrotron X‐ray diffraction (XRD) is applied to cells of magnetotactic bacteria that are pre‐aligned with a magnetic field to determine the crystallographic orientation of magnetosomes relative to the chain axis. The obtained pole figure patterns reveal a [111] fiber texture along the chain direction for magnetospirilla strains MSR‐1 and AMB‐1, whereas a [100] fiber texture is measured for Desulfovibrio magneticus strain RS‐1. The [100] axis appears energetically unfavorable because it represents a magnetic hard axis in magnetite, but can be turned into an effective easy axis by particle elongation along [100] for aspect ratios higher than 1.25, consistent with aspect ratios in RS‐1 magnetosomes determined earlier. The pronounced fiber textures can be explained either by a strain‐specific biological control on crystal orientation at the chain level or by physical alignment effects due to intra‐chain magnetic interactions. In this case, biological control of the axis of elongation would be sufficient to influence the crystallographic texture of the magnetosome chain.     

Trap‐Assisted Recombination via Integer Charge Transfer States in Organic Bulk Heterojunction Photovoltaics

Organic photovoltaics are under intense development and significant focus has been placed on tuning the donor ionization potential and acceptor electron affinity to optimize open circuit voltage. Here, it is shown that for a series of regioregular‐poly(3‐hexylthiophene):fullerene bulk heterojunction (BHJ) organic photovoltaic devices with pinned electrodes, integer charge transfer states present in the dark and created as a consequence of Fermi level equilibrium at BHJ have a profound effect on open circuit voltage. The integer charge transfer state formation causes vacuum level misalignment that yields a roughly constant effective donor ionization potential to acceptor electron affinity energy difference at the donor–acceptor interface, even though there is a large variation in electron affinity for the fullerene series. The large variation in open circuit voltage for the corresponding device series instead is found to be a consequence of trap‐assisted recombination via integer charge transfer states. Based on the results, novel design rules for optimizing open circuit voltage and performance of organic bulk heterojunction solar cells are proposed.     

The impact of dietary cation anion difference (DCAD) on the acid-base balance and calcium metabolism of non-lactating, non-pregnant dairy cows fed equal amounts of different anionic salts

We evaluated the impact of the dietary cation-anion difference (DCAD) on the influence of anionic salts (AS) on the metabolism of dairy cows using a study-design that included control of feed intake. Ten mature, non-lactating, non-pregnant, Holstein-Friesian-crossbreed cows received 2000 mEq of either one of the seven anionic salts tested, two combinations of the anionic salts or water as control via a rumen cannula. Salts and controls were assigned in a 10x10 Latin square design. Whole blood, serum and urine samples were taken during treatment (TP) and washout period. Samples of whole blood were tested for pH, base-excess and bicarbonate concentrations. In urine, pH and net acid-base excretion (NABE) were analysed. Calcium was measured in serum and urine. According to the different batches of hay, five groups of DCAD were created regarding cluster analysis. Changes in urine and blood parameters were statistically analysed for each DCAD group separately. The different DCAD had an impact on the amount of change in acid-base balance (ABB) and calcium metabolism and for how long these changes lasted. In the DCAD group receiving the highest amount of AS (239 mEq/kg dry matter with AS), changes of ABB were only noticeable in urine and these changes only differed from day zero in the first week of TP (P<0.05). In the other four groups changes of ABB were also visible in blood parameters, but only on a few days of TP did the deviations differ significantly (P<0.05) from day zero. Changes of ABB parameters in urine samples were more pronounced than those in blood and differed clearly from day zero (P<0.05). Parallel to the changes of ABB, calcium concentrations in these samples were significantly increased (P<0.001) in all DCAD groups. Except for the highest DCAD group, ionized calcium concentrations changed over time (P<0.020). However, the differences were very small and only differed from day zero on a few TP days. We conclude that the DCAD of a dairy cow's diet has an important impact on the effect of AS on ABB and calcium metabolism with respect to the duration and amount of change. The target regions of DCAD should be clearly below 100 mEq/kg dry matter to ensure the desired effect on ABB and calcium metabolism. Extremely negative DCAD should be avoided to minimize the risk of clinical acidosis induced by AS.     

Enterohemorrhagic <Emphasis Type="Italic">Escherichia coli</Emphasis> (EHEC) in water from karst springs: detection with real-time PCR and isolation of strains

Within 2 months, two water sources in a karst area in Switzerland were sampled 9 times each, and analyzed by real-time PCR for 6 EHEC O-types, Shiga-like-toxin (stx1 and stx2) and intimin (eae) genes. With the exception of O111, 5 O-types were recorded regularly and at high frequencies (O26: 33.3 %; O157: 33.3 %; O104: 66.6 %; O103: 72.2 %; O145: 94.4 %). Genes for Shiga-like-toxins and intimin were almost omnipresent (stx1: 77.8 %; stx2: 83.3 %; eae: 77.8 %). Strain isolation was undertaken for O-groups 26, 103, 104, 145 and 157. Sample selection for strain isolation was based on Cq-values for the O-groups and stx1, stx2 and eae. From selected samples, frozen enrichment cultures were cultivated on EHLY-agar and 50 typical colonies screened for the O-type and genes encoding for stx1, stx2 and eae. With this approach, only one virulent EHEC-strain could be isolated (Escherichia coli O103, stx1 +; stx2 ?; eae +). We carried out one extensive testing with 800 colonies of O-group O145, and no virulent strain was isolated. Our findings showed that PCR-results are not sufficient to formulate epidemiological conclusions and that the isolation of strains is necessary. However, as the detection procedure of EHEC in foods is cumbersome and expensive, the appropriateness of such an approach in official food control is a matter of debate.     

Enterococci from Appenzeller and Schabziger raw milk cheese: antibiotic resistance, virulence factors, and persistence of particular strains in the products

Enterococci are natural residents of human and animal intestinal tracts, and grow to high numbers in a variety of cheeses. The aim of this study was to determine the diversity of enterococci in two types of artisanal raw milk cheese (Schabziger and Appenzeller) and to investigate whether particular strains with triple resistance against chloramphenicol (Chl), tetracycline (Tet), and erythromycin (Ery) persist in the production system. Of 46 cheese samples, a total of 312 Enterococcus strains were isolated over a 5-month period on selective agar plates containing Chl, Tet, or, Ery. Enterococcus faecalis was the predominant species (80.7%), followed by Enterococcus faecium (5.1%), and Enterococcus durans (11.7%). According to the phenotypic resistance patterns, a selection of 150 strains was analyzed with PCR for the presence of genes encoding resistance to Ery (ereA, ereB, mphA, ermA, ermB, ermC, mrsA/mrsB, mefA/mefE), and Tet (tetM, tetL). Because virulence factors have been linked to the pathogenicity of enterococci, the strain selection was also tested for the presence of the following virulence factors: Agg, GelE, Cyl, Esp, EfaAfs, EfaAfm, Cpd, Cob, and Ccf. All tested strains contained at least two of the nine virulence genes taken into analysis. Pulsed-field gel electrophoresis patterns of the isolates showed a limited persistence of several strains over a period of 1 to 2 months in Schabziger, and more than 2 months in Appenzeller. Finally, the enterococcal flora in the two types of cheeses seems to be rather unrelated. Within 150 strains from 25 different cheese samples (11 Appenzeller and 14 Schabziger), 41 pulsed-field gel electrophoresis patterns could be identified, and only 1 of these was found in enterococci from both types of cheese.     

Chemical-Sensory Characteristics and Consumer Responses of Blackcurrant Juices Produced by Different Industrial Processes

Four blackcurrant juices were produced in industrial scale to study the impact of different processes on the sensory-chemical characteristics and hedonic responses of consumers. Two juices were produced without enzymatic treatment of berries with or without further clarification and filtration. The residue was re-pressed using an enzyme-aided processing method to yield the third juice. The forth juice was obtained by conventional enzymatic processing of berries. The enzyme-aided juices were more astringent and bitter than the non-enzymatic juices, mostly due to higher contents of phenolic compounds, lower contents of sugars, and lower pH and sugar/acid ratio. Higher degree of polymerisation and lower procyanidin/prodelphinidin ratio in proanthocyanidins also contributed to higher intensities of astringencies of the enzyme-aided juices. Overall, the non-enzyme-aided juices received higher ranking in flavour, the enzyme-aided juices in odour. Sweetness, roundness, berryness, and high-sugar content were positive drivers for liking, whereas astringency, bitterness and high content of phenolic compounds were negative drivers. High-pectin content masked the astringency and bitterness of the juices. Higher liking ratings correlated with the previous consumption of blackcurrants and higher age of consumers. Gender showed clear impact on consumer rating of the juices. Males liked more enzyme-aided juices than females and vice versa with the juices produced without the use of enzymes. The processes investigated by this study maybe optimised for commercial production of juices targeted for different consumer groups.     

Adult Exposure to Di-N-Butyl Phthalate (DBP) Induces Persistent Effects on Testicular Cell Markers and Testosterone Biosynthesis in Mice

Studies indicate that phthalates are endocrine disruptors affecting reproductive health. One of the most commonly used phthalates, di-n-butyl phthalate (DBP), has been linked with adverse reproductive health outcomes in men, but the mechanisms behind these effects are still poorly understood. Here, adult male mice were orally exposed to DBP (10 or 100 mg/kg/day) for five weeks, and the testis and adrenal glands were collected one week after the last dose, to examine more persistent effects. Quantification of testosterone, androstenedione, progesterone and corticosterone concentrations by liquid chromatography-mass spectrometry showed that testicular testosterone was significantly decreased in both DBP treatment groups, whereas the other steroids were not significantly altered. Western blot analysis of testis revealed that DBP exposure increased the levels of the steroidogenic enzymes CYP11A1, HSD3β2, and CYP17A1, the oxidative stress marker nitrotyrosine, and the luteinizing hormone receptor (LHR). The analysis further demonstrated increased levels of the germ cell marker DAZL, the Sertoli cell markers vimentin and SOX9, and the Leydig cell marker SULT1E1. Overall, the present work provides more mechanistic understanding of how adult DBP exposure can induce effects on the male reproductive system by affecting several key cells and proteins important for testosterone biosynthesis and spermatogenesis, and for the first time shows that these effects persist at least one week after the last dose. It also demonstrates impairment of testosterone biosynthesis at a lower dose than previously reported.     

Severe Obstructive Sleep Apnea Disrupts Vigilance-State-Dependent Metabolism

The direct pathophysiological effects of obstructive sleep apnea (OSA) have been well described. However, the systemic and metabolic consequences of OSA are less well understood. The aim of this secondary analysis was to translate recent findings in healthy subjects on vigilance-state-dependent metabolism into the context of OSA patients and answer the question of how symptomatic OSA influences metabolism and whether these changes might explain metabolic and cardiovascular consequences of OSA. Patients with suspected OSA were assigned according to their oxygen desaturation index (ODI) and Epworth Sleepiness Scale (ESS) score into symptomatic OSA and controls. Vigilance-state-dependent breath metabolites assessed by high-resolution mass spectrometry were used to test for a difference in both groups. In total, 44 patients were eligible, of whom 18 (40.9%) were assigned to the symptomatic OSA group. Symptomatic OSA patients with a median [25%, 75% quartiles] ODI of 40.5 [35.0, 58.8] events/h and an ESS of 14.0 [11.2, 15.8] showed moderate to strong evidence for differences in 18 vigilance-state-dependent breath compounds compared to controls. These identified metabolites are part of major metabolic pathways in carbohydrate, amino acid, and lipid metabolism. Thus, beyond hypoxia per se, we hypothesize that disturbed sleep in OSA patients persists as disturbed sleep-dependent metabolite levels during daytime.