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991.
Wache N Schröder C Koch KW Christoffers J 《Chembiochem : a European journal of chemical biology》2012,13(7):993-998
Diaminoterephthalates with a maleimide moiety were synthesized and used as fluorescence dyes for sensing thiols. Whereas these "NiWa Blue" dyes showed no emission, the conjugate addition of a thiol to the maleimide group turned on a fluorescence at about 400 nm when irradiating the dye at 338 nm. The neuronal-calcium sensor protein recoverin possesses a single cysteine residue at position 39, which reacts with NiWa Blue, and is therefore labeled by a fluorophore with an emission at about 440 nm. In the absence of Ca(2+), irradiation at 280 nm of a tryptophan residue in close proximity to Cys-bound NiWa Blue lead to strong FRET, which was detected by emission of the dye at 440 nm. In the presence of Ca(2+), the protein holds a conformation with distal Trp and Cys residues, thus FRET of irradiated Trp to Cys-bound NiWa Blue was significantly weakened. 相似文献
992.
Bionda N Stawikowski M Stawikowska R Cudic M López-Vallejo F Treitl D Medina-Franco J Cudic P 《ChemMedChem》2012,7(5):871-882
Bacterial infections are becoming increasingly difficult to treat due to the development and spread of antibiotic resistance. Therefore, identifying novel antibacterial targets and new antibacterial agents capable of treating infections by drug-resistant bacteria is of vital importance. The structurally simple yet potent fusaricidin or LI-F class of natural products represents a particularly attractive source of candidates for the development of new antibacterial agents. We synthesized 18 fusaricidin/LI-F analogues and investigated the effects of structure modification on their conformation, serum stability, antibacterial activity, and toxicity toward human cells. Our findings show that substitution of an ester bond in depsipeptides with an amide bond may afford equally potent analogues with improved stability and greatly decreased cytotoxicity. The lower overall hydrophobicity/amphiphilicity of amide analogues in comparison with their parent depsipeptides, as indicated by HPLC retention times, may explain the dissociation of antibacterial activity and human cell cytotoxicity. These results indicate that amide analogues may have significant advantages over fusaricidin/LI-F natural products and their depsipeptide analogues as lead structures for the development of new antibacterial agents. 相似文献
993.
Markus Schr?der Nina Larissa Lutz Ernest Chick Tangwan Ensieh Hajazimi Walter Vetter 《European Food Research and Technology》2012,234(6):955-962
The phytanic acid content in milk correlates with the amount of green items in the cows’ feed. For this reason, the four-fold methyl-branched fatty acid has been suggested as a potential marker for the authentication of organic milk. In this study, we attempted to provide further support for this idea by studying the progression of the phytanic acid level and diastereomer ratio in milk fat by transition of the diets from high proportions of concentrate (typical “conventional” feed) to hay (typical “organic” feed in winter) and back to “conventional” feed. Milk samples taken from three cows were analyzed on both the phytanic acid concentration and diastereomer distribution. The cows were initially fed with “conventional” feed (ground feed with high portions (30–45?%) of concentrate), then the feed was changed within 1?week to 100?% hay (“organic” feed), and after ~6?weeks, the feed of two cows was changed back to the initial feed with concentrate (phase Cb). During the “conventional” feeding at the beginning of the experiment, the phytanic acid concentration was low (100–130?mg/100?g milk fat). When the feed was changed to hay (“organic” feed), the phytanic acid concentration immediately increased to a stable level of about 160?mg/100?g lipids. Changing back the feed to “conventional” feed, the phytanic acid concentration dropped immediately back below the value measured in the initial phase. Likewise, the SRR/RRR-diastereomer distribution of phytanic acid in the milk was an excellent indicator for the changes in the cows’ feed. While the SRR/RRR-diastereomer ratio was >1.5 during “conventional” feeding, it immediately decreased to equal amounts of both diastereomers when hay was supplied as feed. Abandonment of concentrate in conventional feeding increased the phytanic acid content but the SRR-diastereomer was still dominant and thus the SRR/RRR-diastereomer ratio was different to organic milk. Our results indicate that both parameters, i.e., the phytanic acid content and SRR/RRR-diastereomer ratio need to be measured for authentication of organic milk. 相似文献
994.
995.
de Beer D Steyn N Joubert E Muller N 《Journal of the science of food and agriculture》2012,92(13):2741-2750
BACKGROUND: Plum skins are a waste product generated during production of plum juice or pulp. Polyphenols, shown to have various health‐promoting properties, can be recovered from this waste product. Red‐fleshed plum nectar formulations containing plum skin extract in varying amounts were characterised in terms of intensity of sensory attributes, consumer acceptability, colour, polyphenol content and antioxidant activity. Commercial beverages containing red fruits were used as benchmarks. RESULTS: The polyphenolic profile of the plum skin extract was similar to that of the pulp, including anthocyanins, flavonols, flavan‐3‐ols and a phenolic acid. Addition of the extract to plum nectar, which enhanced the colour, polyphenol content and antioxidant capacity, was limited by its negative sensory impact. The formulations were deemed acceptable by consumers, although a decrease in positive sensory attributes (plum flavour, plum aroma and sweetness) and an increase in negative sensory attributes (plant‐like flavour, plant‐like aroma, acidity and astringency) were observed with increasing skin extract content. The formulations compared favourably with commercial beverages in terms of colour total polyphenol content and antioxidant activity. CONCLUSION: Plum skins were successfully used to enhance the functional status of plum nectar. Use of a functional ingredient from plum skins is, therefore, a feasible value‐addition strategy. Copyright © 2012 Society of Chemical Industry 相似文献
996.
997.
Stephen R. H. Langrell Theodore R. Allnutt Val��rie Laval Yves Bertheau Maria Pla Nina Papazova David Lee 《Food Analytical Methods》2011,4(3):313-318
A rapid on-, or near-site, quantitative method for use as a pre-harvest predictive decision, or co-existence monitoring, tool
for adventitious genetically modified (GM) presence has been developed. Based on a laboratory-based protocol for real-time
(RT) quantification of the MON810 GM event in maize kernels, the duplex RT polymerase chain reaction method was constructed
around the portable Cepheid SmartCyclerII platform, requiring only modest support infrastructure for field application. Validation
through an international ring trial showed good compliance with minimum assay performance requirements as defined by the European
Network of GMO Laboratories (RSDr = 18.5%; RSDR = 32.8; Bias = 26.7%). 相似文献
998.
Martina turm Nina Kacjan‐Mari Sonja Lojen 《Journal of the science of food and agriculture》2011,91(2):262-267
BACKGROUND: The nitrogen isotopic fingerprint (δ15N) is reported to be a promising indicator for differentiating between organically and conventionally grown vegetables. However, the effect on plant δ15N of split nitrogen fertilisation, which could enable farmers to cover up the use of synthetic fertiliser, is not well studied. In this study the use of δ15N in lettuce as a potential marker for identifying the use of synthetic nitrogen fertiliser was tested on pot‐grown lettuce (Lactuca sativa L.) treated with synthetic and organic nitrogen fertilisers (single or split application). The effect of combined usage of synthetic and organic fertilisers on δ15N was also investigated. RESULTS: The δ15N values of whole plants treated with different fertilisers differed significantly when the fertiliser was applied in a single treatement. However, additional fertilisation (with isotopically the same or different fertiliser) did not cause a significant alteration of plant δ15N. CONCLUSION: The findings of the study suggest that the δ15N value of lettuce tissues could be used as a rough marker to reveal the history of nitrogen fertilisation, but only in the case of single fertiliser application. However, if the difference in δ15N between the applied synthetic and organic nitrogen fertilisers was > 9.1‰, the detection of split and combined usage of the fertilisers would have greater discriminatory power. Copyright © 2010 Society of Chemical Industry 相似文献
999.
Anita Klaus Maja Kozarski Miomir Niksic Dragica Jakovljevic Nina Todorovic Leo J.L.D. Van Griensven 《LWT》2011,44(10):2005-2011
Antioxidant properties of hot water extract (HWE), hot water extracted polysaccharides (HWP) and hot alkali extracted polysaccharides (HWAE) were obtained from fruiting bodies of the wild basidiomycete Schizophyllum commune. All extracts contained both α- and β-glucans as determined by Megazyme β-glucan assay kit. Glucose was found by TLC and NMR to be the prevalent monosaccharide in all extracts. Total phenol contents were in descending order of HWP ≈ HWE > HWAE. Median effective concentrations (EC50 values) of antioxidant activities were 8.3 ± 0.1, 6.9 ± 0.0 and 8.9 ± 0.1 mg/mL, and of the DPPH scavenging activity 0.8 ± 0.0, 0.6 ± 0.0 and 1.8 ± 0.0 mg/mL, for HWE, HWP and HWAE, respectively. EC50 values of reducing power were 7.6 ± 0.1, 7.9 ± 0.0 and 12.5 ± 0.1 mg/mL, whereas those of the chelating abilities on ferrous ions were 3.1 ± 0.0, 4.6 ± 0.1 and 4.9 ± 0.1 mg/mL. The EC50 values of the antioxidant activity, of the DPPH scavenging, and of the reducing power were correlated with total polysaccharide as well as with total phenol content. The antioxidant activities of all the extracts may be caused by both polysaccharides and polyphenols or by a complex of both. 相似文献
1000.
Pavel A. Melentev Elena V. Ryabova Nina V. Surina Darya R. Zhmujdina Artem E. Komissarov Ekaterina A. Ivanova Natalia P. Boltneva Galina F. Makhaeva Mariana I. Sliusarenko Andriy S. Yatsenko Iryna I. Mohylyak Nataliya P. Matiytsiv Halyna R. Shcherbata Svetlana V. Sarantseva 《International journal of molecular sciences》2021,22(15)
Various neurodegenerative disorders are associated with human NTE/PNPLA6 dysfunction. Mechanisms of neuropathogenesis in these diseases are far from clearly elucidated. Hereditary spastic paraplegia belongs to a type of neurodegeneration associated with NTE/PNLPLA6 and is implicated in neuron death. In this study, we used Drosophila melanogaster to investigate the consequences of neuronal knockdown of swiss cheese (sws)—the evolutionarily conserved ortholog of human NTE/PNPLA6—in vivo. Adult flies with the knockdown show longevity decline, locomotor and memory deficits, severe neurodegeneration progression in the brain, reactive oxygen species level acceleration, mitochondria abnormalities and lipid droplet accumulation. Our results suggest that SWS/NTE/PNPLA6 dysfunction in neurons induces oxidative stress and lipid metabolism alterations, involving mitochondria dynamics and lipid droplet turnover in neurodegeneration pathogenesis. We propose that there is a complex mechanism in neurological diseases such as hereditary spastic paraplegia, which includes a stress reaction, engaging mitochondria, lipid droplets and endoplasmic reticulum interplay. 相似文献