| 1. |
- Dong, Yongjiang, et al.
(författare)
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LED-induced fluorescence system for tea classification and quality assessment
- 2014
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Ingår i: Journal of Food Engineering. - : Elsevier BV. - 0260-8774. ; 137, s. 95-100
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Tidskriftsartikel (refereegranskat)abstract
- A fluorescence system was developed by using several light emitting diodes (LEDs) with different wavelengths as excitation light sources. The fluorescence sensor head consists of multi LED light sources and a multimode fiber for fluorescence collection, where the LEDs and the corresponding filters can be easily chosen to get appropriate excitation wavelengths for different applications. By analyzing fluorescence spectra with the principal component analysis method, the system was utilized in the classification of four types of green tea and two types of black tea beverages. Quality of Xihu Longjing tea leaves of different grades and that of the corresponding liquid tea samples were studied to further investigate the ability and application of the system in the evaluation of classification/quality of tea and other foods. (C) 2014 Elsevier Ltd. All rights reserved.
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| 2. |
- Hykollari, A., et al.
(författare)
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More Than Just Oligomannose: An N-glycomic Comparison of Penicillium Species
- 2016
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Ingår i: Molecular & Cellular Proteomics. - 1535-9476. ; 15:1, s. 73-92
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Tidskriftsartikel (refereegranskat)abstract
- N-glycosylation is an essential set of post-translational modifications of proteins; in the case of filamentous fungi, N-glycans are present on a range of secreted and cell wall proteins. In this study, we have compared the glycans released by peptide/N-glycosidase F from proteolysed cell pellets of three Penicillium species (P. dierckxii, P. nordicum and P. verrucosum that all belong to the Eurotiomycetes). Although the major structures are all within the range Hex(5-11)HexNAc(2) as shown by mass spectrometry, variations in reversed-phase chromatograms and MS/MS fragmentation patterns are indicative of differences in the actual structure. Hydrofluoric acid and mannosidase treatments revealed that the oligomannosidic glycans were not only in part modified with phosphoethanolamine residues and outer chain och1-dependent mannosylation, but that bisecting galactofuranose was present in a species-dependent manner. These data are the first to specifically show the modification of N-glycans in fungi with zwitterionic moieties. Furthermore, our results indicate that mere mass spectrometric screening is insufficient to reveal the subtly complex nature of N-glycosylation even within a single fungal genus.
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| 3. |
- Martini, F., et al.
(författare)
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Highly modified and immunoactive N-glycans of the canine heartworm
- 2019
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- The canine heartworm (Dirofilaria immitis) is a mosquito-borne parasitic nematode whose range is extending due to climate change. In a four-dimensional analysis involving HPLC, MALDI-TOF-MS and MS/MS in combination with chemical and enzymatic digestions, we here reveal an N-glycome of unprecedented complexity. We detect N-glycans of up to 7000 Da, which contain long fucosylated HexNAc-based repeats, as well as glucuronylated structures. While some modifications including LacdiNAc, chitobiose, alpha 1,3-fucose and phosphorylcholine are familiar, anionic N-glycans have previously not been reported in nematodes. Glycan array data show that the neutral glycans are preferentially recognised by IgM in dog sera or by mannose binding lectin when antennal fucose and phosphorylcholine residues are removed; this pattern of reactivity is reversed for mammalian C-reactive protein, which can in turn be bound by the complement component C1q. Thereby, the N-glycans of D. immitis contain features which may either mediate immunomodulation of the host or confer the ability to avoid immune surveillance. RAHAM D, 1991, JOURNAL OF PARASITOLOGY, V77, P254
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| 4. |
- Paschinger, K., et al.
(författare)
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N-glycan antennal modifications are altered in Caenorhabditis elegans lacking the HEX-4 N-acetylgalactosamine-specific hexosaminidase
- 2023
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Ingår i: Journal of Biological Chemistry. - : Elsevier BV. - 0021-9258. ; 299:4
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Tidskriftsartikel (refereegranskat)abstract
- Simple organisms are often considered to have simple gly-comes, but plentiful paucimannosidic and oligomannosidic glycans overshadow the less abundant N-glycans with highly variable core and antennal modifications; Caenorhabditis ele-gans is no exception. By use of optimized fractionation and assessing wildtype in comparison to mutant strains lacking either the HEX-4 or HEX-5 beta-N-acetylgalactosaminidases, we conclude that the model nematode has a total N-glycomic po-tential of 300 verified isomers. Three pools of glycans were analyzed for each strain: either PNGase F released and eluted from a reversed-phase C18 resin with either water or 15% methanol or PNGase Ar released. While the water-eluted frac-tions were dominated by typical paucimannosidic and oligo-mannosidic glycans and the PNGase Ar-released pools by glycans with various core modifications, the methanol-eluted fractions contained a huge range of phosphorylcholine-modified structures with up to three antennae, sometimes with four N-acetylhexosamine residues in series. There were no major differences between the C. elegans wildtype and hex-5 mutant strains, but the hex-4 mutant strains displayed altered sets of methanol-eluted and PNGase Ar-released pools. In keeping with the specificity of HEX-4, there were more glycans capped with N-acetylgalactosamine in the hex-4 mutants, as compared with isomeric chito-oligomer motifs in the wildtype. Considering that fluorescence microscopy showed that a HEX-4::enhanced GFP fusion protein colocalizes with a Golgi tracker, we conclude that HEX-4 plays a significant role in late-stage Golgi processing of N-glycans in C. elegans. Furthermore, finding more "parasite-like" structures in the model worm may facilitate discovery of glycan-processing enzymes occurring in other nematodes.
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| 5. |
- Wang, Binhao, et al.
(författare)
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DETECTION OF GAS CONCENTRATION BY CORRELATION SPECTROSCOPY USING A MULTI-WAVELENGTH FIBER LASER
- 2011
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Ingår i: PROGRESS IN ELECTROMAGNETICS RESEARCH-PIER. - 1559-8985 .- 1070-4698. ; 114, s. 469-479
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Tidskriftsartikel (refereegranskat)abstract
- A correlation spectroscopy (COSPEC) based on a multi-wavelength fiber laser is first proposed for the detection of gas concentration. The lasing wavelengths are selected to match several characteristic absorption peaks of the gas under test, and the gas concentration is easily measured by correlating it with the reference gas. The present method is immune from the instability of the light source and the influence of other gases. The concentration measurement of C2H2 is demonstrated in the experiment in its near-infrared dominant absorption region. The technique has prospects for simultaneous detection of multiple gases, and the measurement of mixed gases of C2H2 and CO2 is also analyzed.
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| 6. |
- Wilson, I. B. H., et al.
(författare)
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Increasing Complexity of the N-Glycome During Caenorhabditis Development
- 2023
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Ingår i: Molecular & Cellular Proteomics. - : Elsevier BV. - 1535-9476 .- 1535-9484. ; 22:3
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Tidskriftsartikel (refereegranskat)abstract
- Caenorhabditis elegans is a frequently employed genetic model organism and has been the object of a wide range of developmental, genetic, proteomic, and glycomic studies. Here, using an off-line MALDI-TOF-MS approach, we have analyzed the N-glycans of mixed embryos and liquid-or plate-grown L4 larvae. Of the over 200 different annotatable N-glycan structures, variations between the stages as well as the mode of cultivation were observed. While the embryonal N-glycome appears less complicated overall, the liquid-and plate-grown larvae differ especially in terms of methylation of bisecting fucose, alpha-gal-actosylation of mannose, and di-6-galactosylation of core alpha 1,6-fucose. Furthermore, we analyzed the O-glycans by LC-electrospray ionization-MS following 6-elimination; especially the embryonal O-glycomes included a set of phosphorylcholine-modified structures, previously not shown to exist in nematodes. However, the set of glycan structures cannot be clearly correlated with levels of gly-cosyltransferase transcripts in developmental RNA-Seq datasets, but there is an indication for coordinated expression of clusters of potential glycosylation-relevant genes. Thus, there are still questions to be answered in terms of how and why a simple nematode synthesizes such a diverse glycome.
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| 7. |
- Yan, Chunsheng, et al.
(författare)
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Design of new multipass gas cells with circular and elliptical cross-section
- 2014
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Ingår i: Microwave and Optical Technology Letters. - : Wiley. - 0895-2477. ; 56:12, s. 3003-3009
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Tidskriftsartikel (refereegranskat)abstract
- Two new types of multipass gas cells with circular and elliptical cross-sections were developed. As for a cylindrical cell, the reflected rays in the circle would be an irregular trace without superposition and termination, if its central angle is a bit more than 2 pi/3 for an example. Each two adjacent reflected points have the same optical path difference and optical light passes through different optical distances before different reflection points. As for a cylindroidal cell, if the optical ray passes through one focus point of the ellipse, it must also pass through the other. The light will exit finally from the termination point of an axis. The optical distance depends on the eccentricity of the ellipse and the size of the emergent window. In this article, the detailed mathematical derivations of the optical multireflection traces for the two structures are presented. The unified formula is developed. It is found that these designs have small volumes and adjustable long optical paths. For example, the optical distances in the two structures are about 625 mm for a circle with 50 mm radius. The performance of the system can be enhanced by coating high total reflection film, increasing the processing and positioning precisions, and using highly collimating laser beam. (C) 2014 Wiley Periodicals, Inc.
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| 8. |
- Yan, Chunsheng
(författare)
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Experimental study of the optical waveguides by scanning near-field optical microscopy (NSOM)
- 2011
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Ingår i: Microwave and optical technology letters (Print). - : Wiley. - 0895-2477 .- 1098-2760. ; 53:7, s. 1658-1663
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Tidskriftsartikel (refereegranskat)abstract
- In this article, the ordinary optical waveguides are investigated by the near field optical microscopy (NSOM). Three kinds of experimental systems are set up and the corresponding operation modes of NSOM (illumination mode, illumination-collection mode and collection mode) are realized and analyzed.
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| 9. |
- Yan, Chunsheng, et al.
(författare)
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Techniques related to graphene biosensors and their potential combination with optical fibres
- 2011
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Ingår i: Materials technology (New York, N.Y.). - 1066-7857 .- 1753-5557. ; 26:4, s. 173-183
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Tidskriftsartikel (refereegranskat)abstract
- From zero-dimensional fullerene to one-dimensional carbon nanotube and to two-dimensional graphene, nanostructures based on carbon element are always one of the most exciting topics in modern science and technology. The work published in the open literature dealing with the properties, synthesis and sensor applications of graphene is overviewed. The potential techniques to realise optical fibre graphene sensors are presented and discussed.
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| 10. |
- Yan, S., et al.
(författare)
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Ablation of N-acetylglucosaminyltransferases in Caenorhabditis induces expression of unusual intersected and bisected N-glycans
- 2018
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Ingår i: Biochimica et Biophysica Acta - General Subjects. - : Elsevier BV. - 0304-4165. ; 1862:10, s. 2191-2203
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Tidskriftsartikel (refereegranskat)abstract
- modification in the Golgi of N-glycans by N-acetylglucosaminyltransferase I (GlcNAc-TI, MGAT1) can be considered to be a hallmark of multicellular eukaryotes as it is found in all metazoans and plants, but rarely in unicellular organisms. The enzyme is key for the normal processing of N-glycans to either complex or paucimannosidic forms, both of which are found in the model nematode Caenorhabditis elegans. Unusually, this organism has three different GlcNAc-TI genes (gly-12, gly-13 and gly-14); therefore, a complete abolition of GlcNAc-TI activity required the generation of a triple knock-out strain. Previously, the compositions of N-glycans from this mutant were described, but no detailed structures. Using an off-line HPLC-MALDI-TOF-MS approach combined with exoglycosidase digestions and MS/MS, we reveal that the multiple hexose residues of the N-glycans of the gly-12;gly-13;gly-14 triple mutant are not just mannose, but include galactoses in three different positions (β-intersecting, β-bisecting and α-terminal) on isomeric forms of Hex4-8HexNAc2 structures; some of these structures are fucosylated and/or methylated. Thus, the N-glycomic repertoire of Caenorhabditis is even wider than expected and exhibits a large degree of plasticity even in the absence of key glycan processing enzymes from the Golgi apparatus.
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