793 research outputs found

    Residents' housing satisfaction in a community development block grant neighborhood

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    The purpose of this research was to assess the relationships of housing satisfaction, the six identified determinants of housing satisfaction (Demographic Characteristics, Social Networks, Participation and Control, Housing Quality, Neighborhood Identity and Cohesion, and Public Services), and participation in a Community Development Block Grant (CDBG) neighborhood housing rehabilitation project to one another. The specific objectives were (a) to determine the attitudes and perceptions of residents toward their housing through self-report and (b) to assess the impact of changes in housing quality on resident satisfaction. The sample consisted of 70 heads of household within the CDBG neighborhood, of which 25 had participated in the project and 45 had not. Crosstabulation of responses to the Neighborhood Resident Questionnaire (NRQ) revealed that general housing satisfaction is related to the six determinants of housing satisfaction, that participation in the CDBG had little effect on housing satisfaction, and that participation in the CDBG is related to the six determinants of housing satisfaction but not in a clear causal sequence. Because participation in the CDBG meant that houses generally were brought "up to code", it was not expected that participation in the CDBG would be significantly related to housing satisfaction

    Parental empathy and family-role interactions as portrayed on commercial television

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    Research studies have found that prosocial behaviors can be learned from viewing select television programs. In a time when the family has been thought of as disintegrating and has few role models for parenting, television could be of prime importance as a source for models of effective parenting and family life in general. This study was a preliminary examination of the potential for television to positively influence parents and future parents. The purpose of this study was to describe television families portrayed on selected programs within the three program formats of Situation Comedies, Action Dramas, and Soap Operas. Data for this study were obtained from nine television programs, with three programs in each program format. Each program was videotape recorded for two consecutive episodes. Two instruments were used as a means of systematically identifying the family behaviors under study. The first instrument, Empathy Measure (Stover, Guerney, & O'Connell, 1971), was used to collect information on the levels of parental empathy by systematically analyzing verbal and nonverbal communications between parents and children

    Characterization of Fluorescent Eye Markers for Mammalian Transgenic Studies

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    Genotyping mice by DNA based methods is both laborious and costly. As an alternative, we systematically examined fluorescent proteins expressed in the lens as transgenic markers for mice. A set of eye markers has been selected such that double and triple transgenic animals can be visually identified and that fluorescence intensity in the eyes can be used to distinguish heterozygous from homozygous mice. Taken together, these eye markers dramatically reduce the time and cost of genotyping transgenics and empower analysis of genetic interaction

    Bridging fluorescence microscopy and electron microscopy

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    Development of new fluorescent probes and fluorescence microscopes has led to new ways to study cell biology. With the emergence of specialized microscopy units at most universities and research centers, the use of these techniques is well within reach for a broad research community. A major breakthrough in fluorescence microscopy in biology is the ability to follow specific targets on or in living cells, revealing dynamic localization and/or function of target molecules. One of the inherent limitations of fluorescence microscopy is the resolution. Several efforts are undertaken to overcome this limit. The traditional and most well-known way to achieve higher resolution imaging is by electron microscopy. Moreover, electron microscopy reveals organelles, membranes, macromolecules, and thus aids in the understanding of cellular complexity and localization of molecules of interest in relation to other structures. With the new probe development, a solid bridge between fluorescence microscopy and electron microscopy is being built, even leading to correlative imaging. This connection provides several benefits, both scientifically as well as practically. Here, I summarize recent developments in bridging microscopy

    Some Secrets of Fluorescent Proteins: Distinct Bleaching in Various Mounting Fluids and Photoactivation of cyan fluorescent proteins at YFP-Excitation

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    Background
The use of spectrally distinct variants of green fluorescent protein (GFP) such as cyan or yellow mutants (CFP and YFP, respectively) is very common in all different fields of life sciences, e.g. for marking specific proteins or cells or to determine protein interactions. In the latter case, the quantum physical phenomenon of fluorescence resonance energy transfer (FRET) is exploited by specific microscopy techniques to visualize proximity of proteins.

Methodology/Principal Findings
When we applied a commonly used FRET microscopy technique - the increase in donor (CFP)-fluorescence after bleaching of acceptor fluorophores (YFP), we obtained good signals in live cells, but very weak signals for the same samples after fixation and mounting in commercial microscopy mounting fluids. This observation could be traced back to much faster bleaching of CFP in these mounting media. Strikingly, the opposite effect of the mounting fluid was observed for YFP and also for other proteins such as Cerulean, TFP or Venus. The changes in photostability of CFP and YFP were not caused by the fixation but directly dependent on the mounting fluid. Furthermore we made the interesting observation that the CFP-fluorescence intensity increases by about 10 - 15% after illumination at the YFP-excitation wavelength – a phenomenon, which was also observed for Cerulean. This photoactivation of cyan fluorescent proteins at the YFP-excitation can cause false-positive signals in the FRET-microscopy technique that is based on bleaching of a yellow FRET acceptor.

Conclusions/Significance
Our results show that photostability of fluorescent proteins differs significantly for various media and that CFP bleaches significantly faster in commercial mounting fluids, while the opposite is observed for YFP and some other proteins. Moreover, we show that the FRET microscopy technique that is based on bleaching of the YFP is prone to artifacts due to photoactivation of cyan fluorescent proteins under these conditions

    Advanced optical imaging in living embryos

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    Developmental biology investigations have evolved from static studies of embryo anatomy and into dynamic studies of the genetic and cellular mechanisms responsible for shaping the embryo anatomy. With the advancement of fluorescent protein fusions, the ability to visualize and comprehend how thousands to millions of cells interact with one another to form tissues and organs in three dimensions (xyz) over time (t) is just beginning to be realized and exploited. In this review, we explore recent advances utilizing confocal and multi-photon time-lapse microscopy to capture gene expression, cell behavior, and embryo development. From choosing the appropriate fluorophore, to labeling strategy, to experimental set-up, and data pipeline handling, this review covers the various aspects related to acquiring and analyzing multi-dimensional data sets. These innovative techniques in multi-dimensional imaging and analysis can be applied across a number of fields in time and space including protein dynamics to cell biology to morphogenesis

    Identification and In Vivo Characterization of NvFP-7R, a Developmentally Regulated Red Fluorescent Protein of Nematostella vectensis

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    In recent years, the sea anemone Nematostella vectensis has emerged as a critical model organism for comparative genomics and developmental biology. Although Nematostella is a member of the anthozoan cnidarians (known for producing an abundance of diverse fluorescent proteins (FPs)), endogenous patterns of Nematostella fluorescence have not been described and putative FPs encoded by the genome have not been characterized.We described the spatiotemporal expression of endogenous red fluorescence during Nematostella development. Spatially, there are two patterns of red fluorescence, both restricted to the oral endoderm in developing polyps. One pattern is found in long fluorescent domains associated with the eight mesenteries and the other is found in short fluorescent domains situated between tentacles. Temporally, the long domains appear simultaneously at the 12-tentacle stage. In contrast, the short domains arise progressively between the 12- and 16-tentacle stage. To determine the source of the red fluorescence, we used bioinformatic approaches to identify all possible putative Nematostella FPs and a Drosophila S2 cell culture assay to validate NvFP-7R, a novel red fluorescent protein. We report that both the mRNA expression pattern and spectral signature of purified NvFP-7R closely match that of the endogenous red fluorescence. Strikingly, the red fluorescent pattern of NvFP-7R exhibits asymmetric expression along the directive axis, indicating that the nvfp-7r locus senses the positional information of the body plan. At the tissue level, NvFP-7R exhibits an unexpected subcellular localization and a complex complementary expression pattern in apposed epithelia sheets comprising each endodermal mesentery.These experiments not only identify NvFP-7R as a novel red fluorescent protein that could be employed as a research tool; they also uncover an unexpected spatio-temporal complexity of gene expression in an adult cnidarian. Perhaps most importantly, our results define Nematostella as a new model organism for understanding the biological function of fluorescent proteins in vivo

    Using Fluorescence Recovery After Photobleaching (FRAP) to study dynamics of the Structural Maintenance of Chromosome (SMC) complex in vivo

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    The SMC complex, MukBEF, is important for chromosome organization and segregation in Escherichia coli. Fluorescently tagged MukBEF forms distinct spots (or 'foci') in the cell, where it is thought to carry out most of its chromosome associated activities. This chapter outlines the technique of Fluorescence Recovery After Photobleaching (FRAP) as a method to study the properties of YFP-tagged MukB in fluorescent foci. This method can provide important insight into the dynamics of MukB on DNA and be used to study its biochemical properties in vivo
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