Changes of Nerve Growth Factor Synthesis in Nonneuronal Cells in Response to Sciatic Nerve Transection

The intact sciatic nerve contains levels of nerve growth factor (NGF) that are comparable to those of densely innervated peripheral target tissues of NGF-responsive (sympathetic and sensory) neurons. There, the high NGF levels are reflected by correspondingly high mRNA^(NGF) levels. In the intact sciatic nerve, mRNA^(NGF) levels were very low, thus indicating that the contribution of locally synthesized NGF by nonneuronal cells is small. However, after transection an increase of up to 15-fold in mRNA^(NGF) was measured in 4-mm segments collected both proximally and distally to the transection site. Distally to the transection site, augmented mRNA^(NGF) levels occurred in all three 4-mm segments from 6 h to 2 wk after transection, the longest time period investigated. The augmented local NGF synthesis after transection was accompanied by a reexpression of NGF receptors by Schwann cells (NGF receptors normally disappear shortly after birth). Proximal to the transection site, the augmented NGF synthesis was restricted to the very end of the nerve stump that acts as a "substitute target organ" for the regenerating NGF-responsive nerve fibers. While the mRNA^(NGF) levels in the nerve stump correspond to those of a densely innervated peripheral organ, the volume is too small to fully replace the lacking supply from the periphery. This is reflected by the fact that in the more proximal part of the transected sciatic nerve, where mRNA^(NGF) remained unchanged, the NGF levels reached only 40% of control values. In situ hybridization experiments demonstrated that after transection all nonneuronal cells express mRNA^(NGF) and not only those ensheathing the nerve fibers of NGF-responsive neurons

Review of \u3ci\u3eHollowing Out the Middle: The Rural Brain Drain and What It Means for America.\u3c/i\u3e By Patrick J. Carr and Maria J. Kefalas.

Hollowing out the middle refers to the loss of the well-educated young adults in rural communities of America\u27s Heartland-the Corn Belt and Great Plains. Declining rural communities invest their meager resources to educate their brightest youth, thereby providing them opportunities for rewarding careers in distant cities. This further contributes to the communities\u27 woes because it guarantees not only population loss, but also loss of expertise and leadership that could help them solve their problems. Carr and Kefalas\u27s contribution to understanding the dilemma of rural communities promoting and supporting the loss of the best and brightest is through an in-depth analysis of young adults\u27 decisions regarding their futures and the role of local institutions and organizations, especially schools, in developing and reinforcing those decisions. They conducted a case study of Ellis, Iowa (a pseudonym), population 2,014, examining the decisions and actions of young adults who graduated from high school in the late 1980s and early 1990s. Their research identified four paths or types: achievers, stayers, seekers, and returners

Farm Operation Characteristics, Institutional Support, and the Use of Soil and Water Conservation Technologies

Technologies to control the severity of soil erosion and water pollution are available, and a large institutional structure supports soil conservation work, but success has been rather limited. This study of a sample of farmers in the three watersheds in central Iowa tests a number of hypotheses about the use of conservation technology. Institutional support factors were found to have a stronger relationship to the use of conservation practices than farm operation characteristics. The erosion potential of the land was conditional for specific conservation practice utilization. The use of institutional resources was positively related to farm size and scale. Thus institutional supports seem to be going to larger farms where the need for conservation practices seems to be greatest, but may not be adequate to encourage the full extent of conservation practices required on the totality of farms

Iowa Farm and Rural Life Poll—2003 Summary Report

Highlights include opinions on community well-being, quality of life, and sense of community. Questions were also asked about biotechnology, food safety, GMOs, and more.https://lib.dr.iastate.edu/extension_communities_pubs/1006/thumbnail.jp

Combinatorial and Chemotopic Odorant Coding in the Zebrafish Olfactory Bulb Visualized by Optical Imaging

AbstractOdors are thought to be represented by a distributed code across the glomerular modules in the olfactory bulb (OB). Here, we optically imaged presynaptic activity in glomerular modules of the zebrafish OB induced by a class of natural odorants (amino acids [AAs]) after labeling of primary afferents with a calcium-sensitive dye. AAs induce complex combinatorial patterns of active glomerular modules that are unique for different stimuli and concentrations. Quantitative analysis shows that defined molecular features of stimuli are correlated with activity in spatially confined groups of glomerular modules. These results provide direct evidence that identity and concentration of odorants are encoded by glomerular activity patterns and reveal a coarse chemotopic organization of the array of glomerular modules

Structural and functional diversification in the teleost S100 family of calcium-binding proteins

<p>Abstract</p> <p>Background</p> <p>Among the EF-Hand calcium-binding proteins the subgroup of S100 proteins constitute a large family with numerous and diverse functions in calcium-mediated signaling. The evolutionary origin of this family is still uncertain and most studies have examined mammalian family members.</p> <p>Results</p> <p>We have performed an extensive search in several teleost genomes to establish the <it>s100 </it>gene family in fish. We report that the teleost S100 repertoire comprises fourteen different subfamilies which show remarkable similarity across six divergent teleost species. Individual species feature distinctive subsets of thirteen to fourteen genes that result from local gene duplications and gene losses. Eight of the fourteen S100 subfamilies are unique for teleosts, while six are shared with mammalian species and three of those even with cartilaginous fish. Several S100 family members are found in jawless fish already, but none of them are clear orthologs of cartilaginous or bony fish <it>s100 </it>genes. All teleost <it>s100 </it>genes show the expected structural features and are subject to strong negative selection. Many aspects of the genomic arrangement and location of mammalian <it>s100 </it>genes are retained in the teleost <it>s100 </it>gene family, including a completely conserved intron/exon border between the two EF hands. Zebrafish <it>s100 </it>genes exhibit highly specific and characteristic expression patterns, showing both redundancy and divergence in their cellular expression. In larval tissue expression is often restricted to specific cell types like keratinocytes, hair cells, ionocytes and olfactory receptor neurons as demonstrated by <it>in situ </it>hybridization.</p> <p>Conclusion</p> <p>The origin of the S100 family predates at least the segregation of jawed from jawless fish and some extant family members predate the divergence of bony from cartilaginous fish. Despite a complex pattern of gene gains and losses the total repertoire size is remarkably constant between species. On the expression level the teleost S100 proteins can serve as precise markers for several different cell types. At least some of their functions may be related to those of their counterparts in mammals. Accordingly, our findings provide an excellent basis for future studies of the functions and interaction partners of <it>s100 </it>genes and finally their role in diseases, using the zebrafish as a model organism.</p