34 research outputs found
Nkg2-C Is a Receptor on Human Natural Killer Cells That Recognizes Sturctures on K562 Target Cells
No full text NKG2-C is a member of the recently discovered NKG2 family of genes and proteins, which are preferentially expressed on human natural killer (NK ) cells. These potential NK cell receptors belong to a larger class of type II transmembrane proteins with a C-type lectin domain. We show here that NKG2-C is expressed as a 36-kDa glycoprotein by translation in vitro, recombinant expression and immunoprecipitiation from a human NK cell clone. Further, a recombinant soluble NKG2-C-receptor binds specifically to K562 cells, which are target cells for NK cell killing , and to RPMI 8866 cells, which are feeder cells for NK cells; several other hematopoietic cell lines tested do not show any binding. The binding structures on the surface of K562 cells disappear, concomitant with a loss in susceptibility to killing when the cells are induced to differentiate with phorbol ester and Ca2+ ionophore. Our data suggest the presence of specific target molecules for NKG2-C on K562 cells, since overall glycosylation, Lewis X and Lewis Y structures, as well as the mucin- like CD43 molecule, do not change following induction of the cells. We propose that NKG2-C mediates a specific interaction of NK cells and their target cells with functional importance for NK cell killing
Fabelbuch für die Jugend
No full textHere is a sturdy book in very good condition featuring a strong chromolithograph pasted onto its cloth cover: King Lion is seated on a raised dias, surrounded by various animals and with an arch behind him proclaiming the title. The subtitle continues "Eine Auslese der besten Fabeln." Julius Hoffmann is not only the publisher. He is also responsible for the prose versions of the 120 fables, each begun with an elaborate initial. The author or source is named after the title of each fable in the text but not in the beginning T of C. Bodemann lists the first edition in 1872 (#347.1) but does not mention further editions. Her description of the first edition fits this copy perfectly. There are 68 pages of texts, interrupted by eight chromolithographs at regular intervals. This book may offer a firm source for these oft-repeated chromolithographs, which appear on cards and other publications. Six of the eight colored full-page illustrations are signed by either of the two artists: FC (frontispiece); "The Miser and the Monkey" (8, after Hagedorn, unsigned); WL (16); TB (24); "The Lion, the Ass, and the Fox" (32); WC (40); "The Fox and the Woodcutter" (48); and "The Ass and the Lapdog" (56: La Fontaine, unsigned). This is a lovely book!Dritte auflageGesammelt und bearbeitet von Julius Hoffman
Spectral image scanning microscopy
No full textFor decades, the confocal microscope has represented one of the dominant imaging systems in biomedical imaging at sub-cellular length scales. Recently, however, it has increasingly been replaced by a related, but more powerful successor technique termed image scanning microscopy (ISM). In this article, we present ISM capable of measuring spectroscopic information such as that contained in fluorescence or Raman images. Compared to established confocal spectroscopic imaging systems, our implementation offers similar spectral resolution, but higher spatial resolution and detection efficiency. Color sensitivity is achieved by a grating placed in the detection path in conjunction with a camera collecting both spatial and spectral information. The multidimensional data is processed using multi-view maximum likelihood image reconstruction. Our findings are supported by numerical simulations and experiments on micro beads and double-stained HeLa cells.</p
Spectral image scanning microscopy
No full textFor decades, the confocal microscope has represented one of the dominant imaging systems in biomedical imaging at sub-cellular length scales. Recently, however, it has increasingly been replaced by a related, but more powerful successor technique termed image scanning microscopy (ISM). In this article, we present ISM capable of measuring spectroscopic information such as that contained in fluorescence or Raman images. Compared to established confocal spectroscopic imaging systems, our implementation offers similar spectral resolution, but higher spatial resolution and detection efficiency. Color sensitivity is achieved by a grating placed in the detection path in conjunction with a camera collecting both spatial and spectral information. The multidimensional data is processed using multi-view maximum likelihood image reconstruction. Our findings are supported by numerical simulations and experiments on micro beads and double-stained HeLa cells.</p
Microfluidics of Small-Population Neurons Allows for a Precise Quantification of the Peripheral Axonal Growth State
No full textNeurons are morphologically the most complex cell types and are characterized by a significant degree of axonal autonomy as well as having efficient means of communication between axons and neuronal cell bodies. For studying the response to axonal injury, compartmentalized microfluidic chambers (MFCs) have become the method of choice because they allow for the selective treatment of axons, independently of the soma, in a highly controllable and reproducible manner. A major disadvantage of these devices is the relatively large number of neurons needed for seeding, which makes them impractical to use with small-population neurons, such as sensory neurons of the mouse. Here, we describe a simple approach of seeding and culturing neurons in MFCs that allows for a dramatic reduction of neurons required to 10,000 neurons per device. This technique facilitates efficient experiments with small-population neurons in compartmentalized MFCs. We used this experimental setup to determine the intrinsic axonal growth state of adult mouse sensory neurons derived from dorsal root ganglia (DRG) and even trigeminal ganglia (TG). In combination with a newly developed linear Sholl analysis tool, we have examined the axonal growth responses of DRG and TG neurons to various cocktails of neurotrophins, glial cell line-derived neurotrophic factor (GDNF), ciliary neurotrophic factor (CNTF) and leptin. Precise quantification of axonal outgrowth revealed specific differences in the potency of each combination to promote axonal regeneration and to switch neurons into an intrinsic axonal growth state. This novel experimental setup opens the way to practicable microfluidic analyses of neurons that have previously been largely neglected simply due to insufficient numbers, including sensory neurons, sympathetic neurons and motor neurons
Differential Labeling of Chemically Modified Peptides and Lipids among Cyanobacteria <em>Planktothrix</em> and <em>Microcystis</em>
No full textThe cyanoHAB forming cyanobacteria Microcystis and Planktothrix frequently produce high intracellular amounts of microcystins (MCs) or anabaenopeptins (APs). In this study, chemically modified MCs and APs have been localized on a subcellular level in Microcystis and Planktothrix applying copper-catalyzed alkyne-azide cycloaddition (CuACC). For this purpose, three different non-natural amino acids carrying alkyne or azide moieties were fed to individual P. agardhii strains No371/1 and CYA126/8 as well as to M. aeruginosa strain Hofbauer showing promiscuous incorporation of various amino acid substrates during non-ribosomal peptide synthesis (NRPS). Moreover, CYA126/8 peptide knock-out mutants and non-toxic strain Synechocystis PCC6803 were processed under identical conditions. Simultaneous labeling of modified peptides with ALEXA405 and ALEXA488 and lipid staining with BODIPY 505/515 were performed to investigate the intracellular location of the modified peptides. Pearson correlation coefficients (PCC) obtained from confocal images were calculated between the different fluorophores and the natural autofluorescence (AF), and between labeled modified peptides and dyed lipids to investigate the spatial overlap between peptides and the photosynthetic complex, and between peptides and lipids. Overall, labeling of modified MCs (M. aeruginosa) and APs (P. agardhii) using both fluorophores revealed increased intensity in MC/AP producing strains. For Synechocystis lacking NRPS, no labeling using either ALEXA405 or ALEXA488 was observed. Lipid staining in M. aeruginosa and Synechocystis was intense while in Planktothrix it was more variable. When compared with AF, both modified peptides and lipids showed a heterologous distribution. In comparison, the correlation between stained lipids and labeled peptides was not increased suggesting a reduced spatial overlap
Subcellular Localization of Sprouty2 in Human Glioma Cells
No full textSprouty proteins act ubiquitously as signaling integrators and inhibitors of receptor tyrosine kinase (RTK) activated pathways. Among the four Sprouty isoforms, Sprouty2 is a key regulator of growth factor signaling in several neurological disorders. High protein levels correlate with reduced survival of glioma patients. We recently demonstrated that abrogating its function inhibits tumor growth by overstimulation of ERK and induction of DNA replication stress. The important role of Sprouty2 in the proliferation of malignant glioma cells prompted us to investigate its subcellular localization applying super-resolution fluorescence and immunoelectron microscopy. We found that cytoplasmic Sprouty2 is not homogenously distributed but localized to small spots (<100 nm) partly attached to vimentin filaments and co-localized with activated ERK. The protein is associated with early, late and recycling endosomes in response to but also independently of growth factor stimulation. The subcellular localization of Sprouty2 in all areas exhibiting strong RTK activities may reflect a protective response of glioma cells to limit excessive ERK activation and to prevent cellular senescence and apoptosis
Correction: Morón-Asensio et al. Differential Labeling of Chemically Modified Peptides and Lipids among Cyanobacteria Planktothrix and Microcystis. Microorganisms 2021, 9, 1578
No full textThe authors wish to make the following corrections to this paper [...
