A connectome and analysis of the adult Drosophila central brain.

The neural circuits responsible for animal behavior remain largely unknown. We summarize new methods and present the circuitry of a large fraction of the brain of the fruit fly Drosophila melanogaster. Improved methods include new procedures to prepare, image, align, segment, find synapses in, and proofread such large data sets. We define cell types, refine computational compartments, and provide an exhaustive atlas of cell examples and types, many of them novel. We provide detailed circuits consisting of neurons and their chemical synapses for most of the central brain. We make the data public and simplify access, reducing the effort needed to answer circuit questions, and provide procedures linking the neurons defined by our analysis with genetic reagents. Biologically, we examine distributions of connection strengths, neural motifs on different scales, electrical consequences of compartmentalization, and evidence that maximizing packing density is an important criterion in the evolution of the fly's brain

Direct quantitative characterization of ligand-receptor binding using two-photon excitation fluroescence cross-correlation spectroscopy: application to the human mu opioid receptor system

Bibliography: p. 206-212Some pages are in colour

Duck Hunter Preferences for Season Dates and Opinions about a Task Force Approach to Setting Season Dates in New York

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Nanoparticles as Fluorescence Labels: Is Size All that Matters?

Fluorescent labels are often used in bioassays as a means to detect and characterize ligand-receptor binding. This is due in part to the inherently high sensitivity of fluorescence-based technology and the relative accessibility of the technique. There is often little concern raised as to whether or not the fluorescent label itself affects the ligand-receptor binding dynamics and equilibrium. This may be particularly important when considering nanoparticle labels. In this study, we examine the affects of nanoparticle (quantum dots and polymer nanospheres) fluorescent labels on the streptavidin-biotin binding system. Since the nanoparticle labels are larger than the species they tag, one could anticipate significant perturbation of the binding equilibrium. We demonstrate, using fluorescence cross-correlation spectroscopy, that although the binding equilibria do change, the relative changes are largely predictable. We suggest that the nanoparticles' mesoscopic size and surface tension effects can be used to explain changes in streptavidin-biotin binding

Quantification of receptor tyrosine kinase transactivation through direct dimerization and surface density measurements in single cells

Cell signaling involves dynamic changes in protein oligomerization leading to the formation of different signaling complexes and modulation of activity. Spatial intensity distribution analysis (SpIDA) is an image analysis method that can directly measure oligomerization and trafficking of endogenous proteins in single cells. Here, we show the use of SpIDA to quantify dimerization/activation and surface transport of receptor protein kinases—EGF receptor and TrkB—at early stages of their transactivation by several G protein-coupled receptors (GPCRs). Transactivation occurred on the same timescale and was directly limited by GPCR activation but independent of G-protein coupling types. Early receptor protein kinase transactivation and internalization were not interdependent for all receptor pairs tested, revealing heterogeneity between groups of GPCRs. SpIDA also detected transactivation of TrkB by dopamine receptors in intact neurons. By allowing for time and space resolved quantification of protein populations with heterogeneous oligomeric states, SpIDA provides a unique approach to undertake single cell multivariate quantification of signaling processes involving changes in protein interactions, trafficking, and activity