Repurposing a photosynthetic antenna protein as a super-resolution microscopy label

Techniques such as Stochastic Optical Reconstruction Microscopy (STORM) and Structured Illumination Microscopy (SIM) have increased the achievable resolution of optical imaging, but few fluorescent proteins are suitable for super-resolution microscopy, particularly in the far-red and near-infrared emission range. Here we demonstrate the applicability of CpcA, a subunit of the photosynthetic antenna complex in cyanobacteria, for STORM and SIM imaging. The periodicity and width of fabricated nanoarrays of CpcA, with a covalently attached phycoerythrobilin (PEB) or phycocyanobilin (PCB) chromophore, matched the lines in reconstructed STORM images. SIM and STORM reconstructions of Escherichia coli cells harbouring CpcA-labelled cytochrome bd 1 ubiquinol oxidase in the cytoplasmic membrane show that CpcA-PEB and CpcA-PCB are suitable for super-resolution imaging in vivo. The stability, ease of production, small size and brightness of CpcA-PEB and CpcA-PCB demonstrate the potential of this largely unexplored protein family as novel probes for super-resolution microscopy

Cellular and humoral sensitivity to gluten fractions in patients with treated nontropical sprue

The presence of circulating antibodies and lymphocyte response to gliadin and fraction III were measured in three groups of 12 patients each. Group I consisted of patients with nontropical sprue maintained on a gluten-free diet; Group II contained patients with other gastrointestinal diseases manifesting malabsorption and Group III was composed of normal controls. Rabbits immunized to both antigens provided positive controls for each method of antibody determination. Results agree with those previously reported in that negligible antibody titers were present to either antigen in normals, patients with other forms of malabsorption or patients with nontropical sprue maintained, for some time, on a gluten-free diet. Lymphocyte stimulation failed to occur with either gluten fraction although the hyporesponsiveness to phytohemagglutinin, previously reported by others, was not observed. Further studies are needed in patients with nontropical sprue following controlled antigenic challenge. Antibody levels in jejunal fluid should also be studied. Until such studies are carried out, evaluation of immunologic factors in the pathogenesis of nontropical sprue will be incomplete.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44378/1/10620_2005_Article_BF02232292.pd

Genomic diversity of bacteriophages infecting Microbacterium spp

The bacteriophage population is vast, dynamic, old, and genetically diverse. The genomics of phages that infect bacterial hosts in the phylum Actinobacteria show them to not only be diverse but also pervasively mosaic, and replete with genes of unknown function. To further explore this broad group of bacteriophages, we describe here the isolation and genomic characterization of 116 phages that infect Microbacterium spp. Most of the phages are lytic, and can be grouped into twelve clusters according to their overall relatedness; seven of the phages are singletons with no close relatives. Genome sizes vary from 17.3 kbp to 97.7 kbp, and their G+C% content ranges from 51.4% to 71.4%, compared to ~67% for their Microbacterium hosts. The phages were isolated on five different Microbacterium species, but typically do not efficiently infect strains beyond the one on which they were isolated. These Microbacterium phages contain many novel features, including very large viral genes (13.5 kbp) and unusual fusions of structural proteins, including a fusion of VIP2 toxin and a MuF-like protein into a single gene. These phages and their genetic components such as integration systems, recombineering tools, and phage-mediated delivery systems, will be useful resources for advancing Microbacterium genetics