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  • 1
    Publication Date: 2022-05-25
    Description: Author Posting. © The Author(s), 2018. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Environmental Science: Nano 5 (2018):904-916, doi:10.1039/C8EN00002F.
    Description: Major molecular mechanisms that underpin the toxicity of nanoparticles (NPs) are the formation of reactive oxygen species and the induction of inflammation. The latter is frequently observed in vitro and in mammalian organisms, yet in aquatic organisms, such NP-induced inflammatory responses remain largely unexplored. Zebrafish offer a wide range of molecular tools to investigate immune responses in an aquatic organism, and were therefore used here to describe how copper (Cu) NPs (25 nm; 1 mg L-1) and soluble Cu as well as polystyrene (PS) NPs (25 nm; 10 mg L1-) induce innate immune responses, focussing on the skin cells and the intestine as likely organs of interaction. mRNA expression of the immune responsive genes interleukin 1 beta (il1β) and immunoresponsive gene 1-like (irg1l) of CuNP exposed embryos was observed to be 46 weaker in the intestinal tissue compared to the rest of the body, indicating a strong outer epithelium response. Specifically, NPs were observed to accumulate in the cavities of lateral neuromasts in the skin, which coincided with an increased local expression of il1β. Exposure to CuNPs triggered the strongest transcriptional changes in pro-inflammatory-related genes and was also observed to increase migration of neutrophils in the tail, indicating a NP-specific inflammatory response. This is the first in vivo evidence for waterborne NP exposure triggering alterations of immune system regulating genes in the skin and intestines of zebrafish embryos. The observed molecular responses have the potential to be linked to adverse effects at higher levels of biological organization and hence might offer screening purposes in nanotoxicology or building blocks for adverse outcome pathways.
    Description: This study was funded by the Marie Skłodowska-Curie Fellowship (H2020-MSCA-IF-2014–655424) granted to Mónica Varela and the NWO-VIDI 864.13.010 granted to Martina G. Vijver.
    Keywords: Copper nanoparticles ; Polystyrene nanoparticles ; Inflammation ; Neuromasts ; Intestine
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
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  • 2
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Previously, we have shown that the nodE gene is a major determinant of the difference in host range between Rhizobium leguminosarum biovars viciae and trifolii. A new genetic test system for stringent functional analysis of nodE genes was constructed. By testing chimeric nodE genes constructed by the exchange of poiymerase chain reaction (PCR)-generated restriction cassettes, we show that a central domain, containing only 44 non-conserved amino acid residues, determines the host specificity of the NodE protein (401 amino acid residues). Mass spectrometric analysis of the lipo-chitin oligosaccharides (LCOs) produced by the new test strain containing the biovar viciae nodE gene shows that molecules containing a polyunsaturated C18:4 (trans-2. trans-4. trans-6. cis-11-octadecatetraenoic) fatty acyl moiety are produced, as is the case for wild-type R. leguminosarum bv. viciae. The LCOs determined by the biovar trifolii nodE gene, which was overproduced in our test strain, carry C1 8:2 and C18:3 fatty acyl chains containing two or three conjugated trans double bonds, respectively. Therefore, the main difference between the nodE-determined LCOs of biovar viviae and trifolii in this system is the presence or absence of one cis double bond, resulting in the very different hydrophobicity of the LCOs. Using a newly developed spot application assay, we show that the 18:2- and C18:3-containing LCOs are able to induce the formation of nodule primordia on roots of Trifolium pratense. On the basis of these and other recent results, we propose that the host range of nodulation of the R. leguminosarum biovars viciae and trifolii is determined by the degree of hydrophobicity of the poly-unsaturated fatty acyl moieties of their LCOs, which is mediated by the host-specific central domain of the NodE protein.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 417 (2002), S. 910-911 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Many plants can grow on soils that are poor in nutrients, and they do so by forming symbiotic associations with microbes. These associations require a molecular dialogue between the two partners. On pages 959 and 962 of this issue, Stracke et al. and Endre et al. describe how they ...
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [s.l.] : Macmillan Magazines Ltd.
    Nature 402 (1999), S. 135-136 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Plant genetics has had a great impact over the past 150 years. In the late nineteenth century Gregor Mendel discovered the basic principles of inheritance using the pea (a leguminous plant). Then, in the 1940s, Barbara McClintock's pioneering work on maize uncovered the existence of mobile DNA ...
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Microbiology 54 (2000), S. 257-288 
    ISSN: 0066-4227
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology
    Notes: Abstract Rhizobia are soil bacteria that can engage in a symbiosis with leguminous plants that produces nitrogen-fixing root nodules. This symbiosis is based on specific recognition of signal molecules, which are produced by both the bacterial and plant partners. In this review, recognition factors from the bacterial endosymbionts are discussed, with particular attention to secreted and cell surface glycans. Glycans that are discussed include the Nod factors, the extracellular polysaccharides, the lipopolysaccharides, the K-antigens, and the cyclic glucans. Recent advances in the understanding of the biosynthesis, secretion, and regulation of production of these glycans are reviewed, and their functions are compared with glycans produced by other bacteria, such as plant pathogens.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The nodulation genes of rhizobia are involved in the production of the lipo-chitin oligosaccharides (LCO), which are signal molecules required for nodule formation. A mutation in nodZ of Bradyrhizobium japonicum results in the synthesis of nodulation signals lacking the wild-type 2-O-methylfucose residue at the reducing-terminal N-acetylglucosamine. This phenotype is correlated with a defective nodulation of siratro (Macroptilium atropurpureum). Here we show that transfer of nodZ to Rhizobium leguminosarum biovar (bv) viciae, which produces LCOs that are not modified at the reducing-terminal N-acetylglucosamine, results in production of LCOs with a fucosyl residue on C-6 of the reducing-terminal N-acetylglucosamine. This finding, together with in vitro enzymatic assays, indicates that the product of nodZ functions as a fucosyltransferase. The transconjugant R. leguminosarum strain producing fucosylated LCOs acquires the capacity to nodulate M. atropurpureumGlycine sojaVigna unguiculata and Leucaena leucocephala. Therefore, nodZ extends the narrow host range of R. leguminosarum bv. viciae to include various tropical legumes. However, microscopic analysis of nodules induced on siratro shows that these nodules do not contain bacteroids, showing that transfer of nodZ does not allow R. leguminosarum to engage in a nitrogen-fixing symbiosis with this plant.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Rhizobium loti is a fast-growing Rhizobium species that has been described as a microsymbiont of plants of the genus Lotus. Nodulation studies show that Lotus plants are nodulated by R loti, but not by most other Rhizobium strains, indicating that R. loti produces specific lipo-chitin oligosaccharides (LCOs) which are necessary for the nodulation of Lotus plants. The LCOs produced by five different Rhizobium ioti strains have been purified and were shown to be N-acetylglucosamine pentasaccharides of which the non-reducing residue is N-methylated and N-acylated with c/s-vaccenic acid (C18:1) or stearic acid (C18:O) and carries a carbamoyl group. In one R. loti strain, NZP2037, an additional carbamoyl group is present on the non-reducing terminal residue. The major class of LCO molecules is substituted on the reducing terminal residue with 4-O-acetylfucose. Addition of LCOs to the roots of Lotus plants results in abundant distortion, swelling and branching of the root hairs, whereas spot inoculation leads to the formation of nodule primordia.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The Rhizobium nodulation genes nodABC are involved in the synthesis of lipo-chitin oligosac-charides. We have analysed the metabolites which are produced in vivo and in vitro by Rhizobium strains which express the single nodA, nodB and nodC genes or combinations of the three. In vivo radioactive labelling experiments, in which D-[1-14C]-glucosamine was used as a precursor, followed by mass spectrometric analysis of the purified radiolabelled metabolic products, showed that Rhizobium strains that only express the combination of the nodB and nodC genes do not produce lipo-chitin oligosaccharides but instead produce chitin oligomers (mainly pentamers) which are devoid of the N-acetyl group on the non-reducing terminal sugar residue (designated NodBC metabolites). Using the same procedure we have shown that when the nodL gene is expressed in addition to the nodBC genes the majority of metabolites contain an additional O-acetyl substituent on the non-reducing terminal sugar residue (designated NodBCL metabolites). The NodBC and NodBCL metabolites purified after in vivo labelling were compared with the radiolabelled metabolites produced in vitro by Rhizobium bacterial cell lysates to which UDP-N-acetyl-D-[U-14C]-glucosamine was added using thin-layer chromatography. The results show that the lysates of strains which expressed the nodBC or nodBCL genes can also produce NodBC and NodBCL metabolites. The same results were obtained when the NodB and NodC proteins were produced separately in two different strains. On the basis of these and other recent results, we propose that NodB is a chitin oilgosaccharide deacetylase, NodC an N-acetylglucosaminyltransferase and, by default, NodA is involved in lipie attachment.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Upon induction of their nodulation genes, the root nodule-inducing Rhizobium bacteria produce lipo-oligosaccharide signal molecules. All lipo-oligosaccharides identified from Rhizobium leguminosarum bv. viciae carry an O-acetyl group at the C-6 position of the non-reducing terminal sugar, the presence of which is important for biological activity and host specificity. Previously we showed that a functional nodL gene product is required for the presence of this O-acetyl moiety. The production of polyclonal antibodies against isolated NodL protein, using a NodL- overproducing Escherichia coli strain is described. These antibodies were used (i) to elucidate the subcellular localization of the NodL protein, which appeared to be present in the cytosol, and (ii) for the purification of native NodL protein from E. coli. Here we provide biochemical proof that purified NodL protein has transacetylating activity in vitro with acetyl-CoA as the acetyl donor. NodL protein appeared to be able to acetylate various substrates, such as lipo-oligosaccharides, chitin fragments and N-acetylglucosamine. For chitinpentaose as the substrate we have shown, using mass spectrometry and NMR spectroscopy, that NodL protein substitutes one O-acetyl group at the C-6 position of the non-reducing terminal sugar.
    Type of Medium: Electronic Resource
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