Control of the J-Aggregation Phenomenon by variation of the N-alkyl-substituents

Cyanine dyes ( 1a–d ) with the 5,5′,6,6′-tetrachloro-1,1′-dialkyl-3,3′-di-(3-carboxypropyl)-benzimidocarbocyanine chromophore differing only in the chain length of their alkyl groups in 1,1′-position have been synthesized, spectroscopically characterized, and compared with 5,5′6,6′-tetrachloro-1,1′-diethyl-3,3′-di-(4-sulfobutyl)-benzimidocarbocyanine( TDBC ). In aqueous solution the dyes form J-aggregates which, depending on the alkyl group chain length, exhibit J-bands differing in spectral positions, bandwidth, and in the number of peaks.     

Impact of neurite alignment on organelle motion

Intracellular transport is pivotal for cell growth and survival. Malfunctions in this process have been associated with devastating neurodegenerative diseases, highlighting the need for a deeper understanding of the mechanisms involved. Here, we use an experimental methodology that leads neurites of differentiated PC12 cells into either one of two configurations: a one-dimensional configuration, where the neurites align along lines, or a two-dimensional configuration, where the neurites adopt a random orientation and shape on a flat substrate. We subsequently monitored the motion of functional organelles, the lysosomes, inside the neurites. Implementing a time-resolved analysis of the mean-squared displacement, we quantitatively characterized distinct motion modes of the lysosomes. Our results indicate that neurite alignment gives rise to faster diffusive and super-diffusive lysosomal motion than the situation in which the neurites are randomly oriented. After inducing lysosome swelling through an osmotic challenge by sucrose, we confirmed the predicted slowdown in diffusive mobility. Surprisingly, we found that the swelling-induced mobility change affected each of the (sub-/super-)diffusive motion modes differently and depended on the alignment configuration of the neurites. Our findings imply that intracellular transport is significantly and robustly dependent on cell morphology, which might in part be controlled by the extracellular matrix.     

Label-Free Study of the Global Cell Behavior during Exposure to Environmental Radiofrequency Fields in the Presence or Absence of Pro-Apoptotic or Pro-Autophagic Treatments

It remains controversial whether exposure to environmental radiofrequency signals (RF) impacts cell status or response to cellular stress such as apoptosis or autophagy. We used two label-free techniques, cellular impedancemetry and Digital Holographic Microscopy (DHM), to assess the overall cellular response during RF exposure alone, or during co-exposure to RF and chemical treatments known to induce either apoptosis or autophagy. Two human cell lines (SH-SY5Y and HCT116) and two cultures of primary rat cortex cells (astrocytes and co-culture of neurons and glial cells) were exposed to RF using an 1800 MHz carrier wave modulated with various environmental signals (GSM: Global System for Mobile Communications, 2G signal), UMTS (Universal Mobile Telecommunications System, 3G signal), LTE (Long-Term Evolution, 4G signal, and Wi-Fi) or unmodulated RF (continuous wave, CW). The specific absorption rates (S.A.R.) used were 1.5 and 6 W/kg during DHM experiments and ranged from 5 to 24 W/kg during the recording of cellular impedance. Cells were continuously exposed for three to five consecutive days while the temporal phenotypic signature of cells behavior was recorded at constant temperature. Statistical analysis of the results does not indicate that RF-EMF exposure impacted the global behavior of healthy, apoptotic, or autophagic cells, even at S.A.R. levels higher than the guidelines, provided that the temperature was kept constant.     

Effect of Drought and Methyl Jasmonate Treatment on Primary and Secondary Isoprenoid Metabolites Derived from the MEP Pathway in the White Spruce Picea glauca

White spruce (Picea glauca) emits monoterpenes that function as defensive signals and weapons after herbivore attack. We assessed the effects of drought and methyl jasmonate (MeJA) treatment, used as a proxy for herbivory, on monoterpenes and other isoprenoids in P. glauca. The emission of monoterpenes was significantly increased after MeJA treatment compared to the control, but drought suppressed the MeJA-induced increase. The composition of the emitted blend was altered strongly by stress, with drought increasing the proportion of oxygenated compounds and MeJA increasing the proportion of induced compounds such as linalool and (E)-β-ocimene. In contrast, no treatment had any significant effect on the levels of stored monoterpenes and diterpenes. Among other MEP pathway-derived isoprenoids, MeJA treatment decreased chlorophyll levels by 40%, but had no effect on carotenoids, while drought stress had no impact on either of these pigment classes. Of the three described spruce genes encoding 1-deoxy-D-xylulose-5-phosphate synthase (DXS) catalyzing the first step of the MEP pathway, the expression of only one, DXS2B, was affected by our treatments, being increased by MeJA and decreased by drought. These findings show the sensitivity of monoterpene emission to biotic and abiotic stress regimes, and the mediation of the response by DXS genes.     

Chromium remediation or release? Effect of iron(II) sulfate addition on chromium(VI) leaching from columns of chromite ore processing residue

Chromite ore processing residue (COPR), derived from the so-called high lime processing of chromite ore, contains high levels of Cr(III) and Cr(VI) and has a pH between 11 and 12. Ferrous sulfate, which is used for remediation of Cr(VI) contamination in wastewater and soils via reduction to Cr(III) and subsequent precipitation of iron(III)/chromium(III) hydroxide, has also been proposed for remediation of Cr(VI) in COPR. Instead, however, addition of FeSO4 to the infiltrating solution in column experiments with COPR greatly increased leaching of Cr(VI). Leached Cr(VI) increased from 3.8 to 12.3 mmol kg(-1) COPR in 25 pore volumes with 20 mM FeSO4, reaching solution concentrations as high as 1.6 mM. Fe(II) was ineffective in reducing Cr(VI) to Cr(III) because it precipitated when it entered the column due to the high pH of COPR, while Cr(VI) in solution was transported away with the infiltrating solution. The large increase in leaching of Cr(VI) upon infiltration of sulfate, either as FeSO4 or Na2SO4, was caused by anion exchange of sulfate for chromate in the layered double hydroxide mineral hydrocalumite, a process for which scanning electron microscopy with energy-dispersive X-ray microanalysis provided direct evidence.     

A Blend of Essential Plant Oils Used as an Additive to Alter Silage Fermentation or Used as a Feed Additive for Lactating Dairy Cows

A blend of essential plant oils was evaluated for its effects on silage fermentation and animal performance. In the first experiment, the blend of essential oils was mixed with freshly chopped whole-plant corn to achieve a concentration of 0, 40, or 80 mg of active product per kilogram of fresh forage weight. Whole-plant corn was also mixed with a buffered propionic acid-based product at 0.2% of fresh forage weight. The blend of essential oils did not affect the populations of yeasts, molds, lactic acid bacteria, or enterobacteria; the fermentation end products; or the aerobic stability of the corn silage. Addition of the buffered propionic acid additive moderately reduced the production of acids during fermentation and resulted in a small reduction in the numbers of yeasts after ensiling, but did not affect aerobic stability. In a second experiment, 30 Holstein cows (4 primiparous and 26 multiparous) averaging 118 ± 70 d in milk and producing 38 ± 16 kg of milk/d were fed a total mixed ration, once daily, that consisted of (on a DM basis) 25% corn silage, 15% alfalfa silage, 10% alfalfa hay, and 50% concentrate. One-half of the cows were fed a blend of essential oils that was mixed directly into their total mixed ration to provide 1.2 g/cow per d for 9 wk. Cows fed the essential oils ate 1.9 kg more dry matter/d and produced 2.7 kg more 3.5% fat-corrected milk/d than did cows fed the control diet. The percentages of milk fat and protein, the somatic cell count numbers, and the concentrations of milk urea nitrogen were unaffected by treatment. Feed efficiency, change in body weight, and change in body condition scoring were also similar between treatments. After 12 h of incubation, the addition of a moderate dose and a high dose of essential oils to in vitro ruminal fermentations had no effect on the concentration of total VFA compared with the control treatment. However, they decreased the molar proportions of acetic, butyric, and valeric acids and increased the proportion of propionic acid. The blend of essential oils evaluated in this study altered in vitro ruminal fermentation and improved animal performance when fed directly to cows, but it did not affect the fermentation or aerobic stability of corn silage.     

The Role of Cytochrome P450 1B1 in Dibenzo[ a,l ]pyrene-induced Carcinogenesis

In human cells, the most carcinogenic polycyclic aromatic hydrocarbon dibenzo[ a,l ]pyrene (DB[ a,l ]P) forms high levels of DNA adducts through formation of the ( m )- anti -(11 R ,12 S )-diol (13 S ,14 R )-epoxide (DB[ a,l ]PDE) and its metabolic precursor, the ( m )-(11 R ,12 R )-diol. Generation of these adducts results from the catalytic activity of cytochrome P450 (P450) 1A1 and 1B1. Additional adducts such as (+)- syn -DB[ a,l ]PDE-DNA or more polar DNA adducts were detected only after increasing exposure doses of the parent compound or in cells that express P450 1A1. At low concentrations (·;100 nM) exclusively ( m )- anti -DB[ a,l ]PDE-DNA adducts were formed by P450 1B1, which is constitutively expressed in many mammalian tissues. Measurement of DNA binding and mutagenicity of DB[ a,l ]P in V79 cells expressing human P450 enzymes revealed a higher activity of P450 1B1 compared to 1A1 at low concentrations. Treatment of P450 1B1 knockout mice and DNA binding studies with fibroblasts isolated from these animals provided further evidence for the central role of P450 1B1-catalyzed formation of ( m )- anti -DB[ a,l ]PDE-DNA adducts in DB[ a,l ]P-induced carcinogenesis.     

trans fatty acids, 5. Fatty acid composition of lipids of the brain and other organs in suckling piglets

The effects of dietarytrans fatty acids on the fatty acid composition of the brain in comparison with other organs were studied in 3-wk-old suckling piglets. In Experiment (Expt.) 1 the piglets were delivered from sows fed partially hydrogenated fish oil (PHFO) (28%trans), partially hydrogenated soybean oil (PHSBO) (36%trans) or lard (0%trans). In Expt. 2 the piglets were delivered from sows fed PHFO, hydrogenated fish oil (HFO) (19%trans) or coconut fat (CF) (0%trans) with two levels of dietary linoleic acid (1 and 2.7%) according to factorial design. In both experiments the mother's milk was the piglets' only food. The level of incorporation oftrans fatty acids in the organs was dependent on the levels in the diets and independent of fat source (i.e., PHSBO, PHFO or HFO). Incorporation oftrans fatty acids into brain PE (phosphatidylethanolamine) was non-detectable in Expt. 1. In Expt. 2, small amounts (less than 0.5%) of 18∶1trans isomers were found in the brain, the level being slightly more on the lower level of dietary linoleic acid compared to the higher. In the other organs the percentage of 18∶1trans increased in the following order: heart PE, liver mitochondria PE, plasma lipids and subcutaneous adipose tissue. Small amounts of 20∶1trans were found in adipose tissue and plasma lipids. Other very long-chain fatty acids from PHFO or HFO (i.e., 20∶1cis and 22∶1cis+trans) were found in all organ lipids except for brain PE. Dietarytrans fatty acids increased the percentage of 22∶5n−6 in brain PE. Except for the brain and the heart, dietarytrans fatty acids reduced the percentage of saturated fatty acids and increased the percentage of monoenoic acids (includingtrans). The overall conclusion was that dietarytrans fatty acids had no noticeable effect on the brain PE composition but slight to moderate effects on the fatty acid profile of other organs of suckling piglets.     

Photochemie und Photophysik von 3-(2-Isoxazolinyl)-phenylketonen

Photochemistry and Photophysics of 3-(2-Isoxazolinyl)-phenylketones 3-Benzoyl-Δ²-1,2-oxazolines ( 1–6 ) are formed by 1,3-dipolar cycloaddition between benzoylnitril-N-oxide ( 8 ) and dihydrofurane 9 or 1,3-dioxep-5-enes ( 10a–c ). The preparative yields are small due to the competitive dimerization of the dipole 8 . Two stereoisomers are obtained by using 2-substituted 1,3-dioxep-5-enes as dipolarophiles. The different steric position of the substituents in 3–6 gives rise to different spectral data. The synthesized ketones possess triplet states with a high degree of charge transfer character. Therefore, the ability to H-abstraction reaction from alcohols is small. For ketone 2 and methanol as H-donor a rate constant of k = 4,1 · 10² M⁻¹s⁻¹ is determined. Also by electron transfer reactions with triethylamine and some onium compounds the reactivity of the T₁ of the ketones 1–6 is less compared to those of nπ* excited ketones. The photolysis of the ketones takes place very unselectively and leads to a product mixture. The quantum yields for the decay of the ketones are 10⁻² to 10⁻³.