Discrimination of human cytotoxic lymphocytes from regulatory and B-lymphocytes by orthogonal light scattering

Light scattering properties of human lymphocyte subpopulations selected by immunofluorescence were studied with a flow cytometer. Regulatory and B-lymphocytes showed a low orthogonal light scatter signal, whereas cytotoxic lymphocytes identified with leu-7, leu-11 and leu-15 revealed a large orthogonal light scatter signal. Two populations in light scatter histograms could be observed with monoclonal antibodies directed against determinants present on both regulatory and cytotoxic lymphocytes. By analysis of the lymphocytes of 16 individuals we found a linear relation between the number of cells with a large orthogonal light scattering and the number of cytotoxic lymphocytes identified with leu-7, leu-11 and leu-15. These observations demonstrate physical differences between cytotoxic lymphocytes and regulatory and B lymphocytes. Moreover, the results suggest a method to estimate the amount of cytotoxic lymphocytes without using monoclonal antibodies

Tapping into Social Media Data to Identify the Public\u27s Most Valued Landscapes

Today, millions of people are using social media to share information and images about the places they visit for outdoor recreation and leisure. This fact sheet reviews recent research which analyzed over 7.5 million photos posted to Instagram, Flickr, and Panaramio to examine which European landscapes individuals value most. The research is the first of its kind to use social media data to identify the public’s most valued landscapes across an entire continent

Mapping Landscape Values Using Social Media

Social media data are providing scientists with a variety of new ways to examine how and why individuals value particular natural landscapes. In this fact sheet, we review cutting edge research that used millions of photos posted to Instagram, Flickr and Panaramio to examine which European landscapes individuals value most. The research is the first of its kind to use social media data to identify the public’s most valued landscapes across an entire continent. The research is also the first to compare the spatial agreement between geotagged imagery uploaded to different platforms

Mercuration of vanillyl-alcohol oxidase from Penicillium simplicissimum generates inactive dimers

Vanillyl-alcohol oxidase (EC 1.1.3.7) from Penicillium simplicissimum was modified with p-mercuribenzoate. One cysteine residue reacts rapidly without loss of enzyme activity. Three sulfhydryl groups then react in an `all or none process' involving enzyme inactivation and dissociation of the octamer into dimers. The inactivation reaction is slowed down in the presence of the competitive inhibitor isoeugenol and fully reversible by treatment of the modified enzyme with dithiothreitol. Vanillyl-alcohol oxidase is more rapidly inactivated at low enzyme concentrations and protected from mercuration by antichaotropic salts. It is proposed that subunit dissociation accounts for the observed sensitivity of vanillyl-alcohol oxidase crystals towards mercury compounds

Substrate binding tunes the reactivity of hispidin 3-hydroxylase, a flavoprotein monooxygenase involved in fungal bioluminescence

Fungal bioluminescence was recently shown to depend on a unique oxygen-dependent system of several enzymes. However, the identities of the enzymes did not reveal the full biochemical details of this process, as the enzymes do not bear resemblance to those of other luminescence systems, and thus the properties of the enzymes involved in this fascinating process are still unknown. Here, we describe the characterization of the penultimate enzyme in the pathway, hispidin 3-hydroxylase, from the luminescent fungus Mycena chlorophos (McH3H), which catalyzes the conversion of hispidin to 3-hydroxyhispidin. 3-Hydroxyhispidin acts as a luciferin substrate in luminescent fungi. McH3H was heterologously expressed in Escherichia coli and purified by affinity chromatography with a yield of 100 mg/liter. McH3H was found to be a single component monomeric NAD(P)H-dependent FAD-containing monooxygenase having a preference for NADPH. Through site-directed mutagenesis, based on a modeled structure, mutant enzymes were created that are more efficient with NADH. Except for identifying the residues that tune cofactor specificity, these engineered variants may also help in developing new hispidin-based bioluminescence applications. We confirmed that addition of hispidin to McH3H led to the formation of 3-hydroxyhispidin as sole aromatic product. Rapid kinetic analysis revealed that reduction of the flavin cofactor by NADPH is boosted by hispidin binding by nearly 100-fold. Similar to other class A flavoprotein hydroxylases, McH3H did not form a stable hydroperoxyflavin intermediate. These data suggest a mechanism by which the hydroxylase is tuned for converting hispidin into the fungal luciferin.</p