"Plugging into Enzymes": nanowiring of redox enzymes by a gold nanoparticle

The reconstitution of an apo-flavoenzyme, apo-glucose oxidase, on a 1.4-nanometer gold nanocrystal functionalized with the cofactor flavin adenine dinucleotide and integrated into a conductive film yields a bioelectrocatalytic system with exceptional electrical contact with the electrode support. The electron transfer turnover rate of the reconstituted bioelectrocatalyst is approximately 5000 per second, compared with the rate at which molecular oxygen, the natural cosubstrate of the enzyme, accepts electrons (approximately 700 per second). The gold nanoparticle acts as an electron relay or "electrical nanoplug" for the alignment of the enzyme on the conductive support and for the electrical wiring of its redox-active center.     

The evolution of modern eukaryotic phytoplankton

The community structure and ecological function of contemporary marine ecosystems are critically dependent on eukaryotic phytoplankton. Although numerically inferior to cyanobacteria, these organisms are responsible for the majority of the flux of organic matter to higher trophic levels and the ocean interior. Photosynthetic eukaryotes evolved more than 1.5 billion years ago in the Proterozoic oceans. However, it was not until the Mesozoic Era (251 to 65 million years ago) that the three principal phytoplankton clades that would come to dominate the modern seas rose to ecological prominence. In contrast to their pioneering predecessors, the dinoflagellates, coccolithophores, and diatoms all contain plastids derived from an ancestral red alga by secondary symbiosis. Here we examine the geological, geochemical, and biological processes that contributed to the rise of these three, distantly related, phytoplankton groups.     

Legionnaires' disease: structural characteristics of the organism

The Legionnaires' disease organism was isolated from lung tissue taken from two fatalities of the Legionnaires' disease epidemic that occurred in Philadelphia during 1976. In yolk sac tissue the agent grew as a small coccobacillary microorgansim, which was Gram variable and Giménez positive. Intracellular coccoid and bacillary forms, detected by electron microscopy, within and without vacuoles, underwent multiplication by septate binary fission. Some of the intracellular forms resembled obligate intracellular pathogens. On defined bacteriologic media, the organisms were predominantly bacillary. The organism conforms to the morphologic criteria of a prokaryocyte.     

Sodium- and potassium-activated adenosine triphosphatase of gills: role in adaptation of teleosts to salt water

The activity of adenosine triphosphatase activated by sodium and potassium ions is greatly increased in the gill and pseudobranch of the euryhaline killifish, Fundulus heteroclitus, after its adaptation to seawater. Adenosine triphosphatase activity in gills of fish in salt water is reduced by hypophysectomy. The data suggest that this enzyme is involved in the excretion of sodiumions by the gill and that the adaptive increase which occurs in seawater is influenced by the hypophysis.     

Spatiotemporal normalized ratio methodology to evaluate the impact of field-scale variable rate application

Precision Agriculture - Wide assimilation of precision agriculture among farmers is currently dependent on the ability to demonstrate its efficiency at the field-scale. Yet, most experiments that...     

Detection of bovine virus diarrhea virus in cell culture using an immunoperoxidase technique

An indirect immunoperoxidase staining technique was developed for identifying cell cultures infected with bovine virus diarrhea virus. Infected cell monolayers stained intensely while uninfected monolayers remained colorless. Immunoperoxidase staining was as sensitive as direct immunofluorescence in detecting endpoint dilutions of virus suspensions. Using the immunoperoxidase technique, infected monolayers were detectable by macroscopic, as well as microscopic, observation.