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High-resolution Confocal Microscopy (high-resolution + confocal_microscopy)

Distribution by Scientific Domains
Life Sciences75%

Selected Abstracts

Three-dimensional distribution of no sources in a primary mechanosensory integration center in the locust and its implications for volume signaling

THE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 15 2010
Daniel Münch
Abstract Nitric oxide (NO) is an evolutionarily conserved mediator of neural plasticity. Because NO is highly diffusible, signals from multiple sources might combine in space and time to affect the same target. Whether such cooperative effects occur will depend on the effective signaling range and on the distances of NO sources to one another and to their targets. These anatomical parameters have been quantified in only few systems. We analyzed the 3D architecture of NO synthase (NOS) expression in a sensory neuropil, the ventral association center (VAC) of the locust. High-resolution confocal microscopy revealed NOS immunoreactive fiber boutons in submicrometer proximity to both the axon terminals of sensory neurons and their postsynaptic target, interneuron A4I1. Pharmacological manipulation of NO signaling affected the response of A4I1 to individual wind-puff stimuli and the response decrement during repetitive stimulation. Mapping NOS immunoreactivity in defined volumes around dendrites of A4I1 revealed NOS-positive fiber boutons within 5 ,m of nearly every surface point. The mean distances between neighboring NOS-boutons and between any point within the VAC and its nearest NOS-bouton were likewise about 5 ,m. For an NO signal to convey the identity of its source, the effective signaling range would therefore have to be less than 5 ,m, and shorter still when multiple boutons release NO simultaneously. The architecture is therefore well suited to support the cooperative generation of volume signals by interaction between the signals from multiple active boutons. J. Comp. Neurol. 518:2903,2916, 2010. © 2010 Wiley-Liss, Inc. [source]

Three-dimensional distribution of NO sources in a primary mechanosensory integration center in the locust and its implications for volume signaling

THE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 15 2010
Daniel Münch
Abstract Nitric oxide (NO) is an evolutionarily conserved mediator of neural plasticity. Because NO is highly diffusible, signals from multiple sources might combine in space and time to affect the same target. Whether such cooperative effects occur will depend on the effective signaling range and on the distances of NO sources to one another and to their targets. These anatomical parameters have been quantified in only few systems. We analyzed the 3D architecture of NO synthase (NOS) expression in a sensory neuropil, the ventral association center (VAC) of the locust. High-resolution confocal microscopy revealed NOS immunoreactive fiber boutons in submicrometer proximity to both the axon terminals of sensory neurons and their postsynaptic target, interneuron A4I1. Pharmacological manipulation of NO signaling affected the response of A4I1 to individual wind-puff stimuli and the response decrement during repetitive stimulation. Mapping NOS immunoreactivity in defined volumes around dendrites of A4I1 revealed NOS-positive fiber boutons within 5 ,m of nearly every surface point. The mean distances between neighboring NOS-boutons and between any point within the VAC and its nearest NOS-bouton were likewise about 5 ,m. For an NO signal to convey the identity of its source, the effective signaling range would therefore have to be less than 5 ,m, and shorter still when multiple boutons release NO simultaneously. The architecture is therefore well suited to support the cooperative generation of volume signals by interaction between the signals from multiple active boutons. J. Comp. Neurol. 518:2903,2916, 2010. © 2010 Wiley-Liss, Inc. [source]

Gene position within chromosome territories correlates with their involvement in distinct rearrangement types in thyroid cancer cells

GENES, CHROMOSOMES AND CANCER, Issue 3 2009
Manoj S. Gandhi
Chromosomal rearrangements in human cancers are of two types, interchromosomal, which are rearrangements that involve exchange between loci located on different chromosomes, and intrachromosomal, which are rearrangements that involve loci located on the same chromosome. The type of rearrangement that typically activates a specific oncogene may be influenced by its nuclear location and that of its partner. In interphase nuclei, each chromosome occupies a distinct three-dimensional (3D) territory that tends to not overlap the territories of other chromosomes. It is also known that after double strand breaks in the genome, mobility of free DNA ends is limited. These considerations suggest that loci located deep within a chromosomal territory might not participate in interchromosomal rearrangements as readily as in intrachromosomal rearrangements. To test this hypothesis, we used fluorescence in situ hybridization with 3D high-resolution confocal microscopy to analyze the positions of six oncogenes known to be activated by recombination in human cancer cells. We found that loci involved in interchromosomal rearrangements were located closer to the periphery of chromosome territories as compared with the loci that were involved in intrachromosomal inversions. The results of this study provide evidence suggesting that nuclear architecture and location of specific genetic loci within chromosome territories may influence their participation in intrachromosomal or interchromosomal rearrangements in human thyroid cells. © 2008 Wiley-Liss, Inc. [source]

Mutations of the RDX gene cause nonsyndromic hearing loss at the DFNB24 locus,,

HUMAN MUTATION, Issue 5 2007
Shahid Y. Khan
Abstract Ezrin, radixin, and moesin are paralogous proteins that make up the ERM family and function as cross-linkers between integral membrane proteins and actin filaments of the cytoskeleton. In the mouse, a null allele of Rdx encoding radixin is associated with hearing loss as a result of the degeneration of inner ear hair cells as well as with hyperbilirubinemia due to hepatocyte dysfunction. Two mutant alleles of RDX [c.1732G>A (p.D578N) and c.1404_1405insG (p.A469fsX487)] segregating in two consanguineous Pakistani families are associated with neurosensory hearing loss. Both of these mutant alleles are predicted to affect the actin-binding motif of radixin. Sequence analysis of RDX in the DNA samples from the original DFNB24 family revealed a c.463C>T transition substitution that is predicted to truncate the protein in the FERM domain (F for 4.1, E for ezrin, R for radixin, and M for moesin) (p.Q155X). We also report a more complete gene and protein structure of RDX, including four additional exons and five new isoforms of RDX that are expressed in human retina and inner ear. Further, high-resolution confocal microscopy in mouse inner ear demonstrates that radixin is expressed along the length of stereocilia of hair cells from both the organ of Corti and the vestibular system. Hum Mutat 28(5), 417,423, 2007. Published 2007 Wiley-Liss, Inc. [source]