Membrane traffic fuses with cartilage development

AbstractThe ability of cells to synthesize and secrete proteins is essential for numerous cellular functions. Therefore, when mutations in one component of the secretory pathway result in a tissue-specific defect, a unique opportunity arises to examine the molecular mechanisms at play. The recent finding that a defect in the protein sedlin, whose yeast counterpart is involved in the first step of the secretory pathway, leads to a cartilage-specific disorder in humans raises numerous questions and interesting possibilities for understanding both the pathobiology involved and the role of membrane traffic in normal cartilage development

A Perfect War : Politics and Parties in Louisiana, 1824--1861.

My dissertation explores Louisiana\u27s political development from 1824 to 1861. Many antebellum state studies have been written, but none focus specifically on Louisiana. While sharing the rest of the South\u27s commitment to slavery and cotton, Louisiana possessed atypical attributes including: a unique ethnic composition, a sugar cane crop dependent upon a protective tariff, and the presence of New Orleans, the South\u27s foremost commercial city. Louisiana\u27s antebellum political situation resulted from the interaction of these distinctive traits with the characteristics that Louisiana shared in common with the rest of the United States. The primary focus of this political narrative is the development of parties and the interaction between parties and the electorate. During the 1820s and 1830s, Louisianans moved from a political system based on personality and ethnicity to a distinct party system with Democrats competing against Whigs. These parties, which were evenly matched, battled until the Whig party collapsed in the 1850s. Subsequently, the nativist Know Nothing party rose and fell. And, in 1861, after an increase in tension over the slavery issue, Louisiana seceded from the Union. Through its examination of Louisiana politics, my dissertation addresses several key historiographical questions. I investigate the relationship between state and federal parties and the role of individuals in party politics. I also explore the impact of both the ideology of republicanism and of the politics of slavery. Moreover, I probe the role played by ethnic diversity, which often overshadowed partisan allegiance. Additionally, I analyze the differences and similarities among the parties\u27 programs---especially concerning the value of governmental activism. My dissertation also discusses the rise of Jacksonian democracy. Louisiana\u27s 1812 constitution restricted voting and office-holding. Later constitutions, written in 1845 and 1852, adopted universal white male suffrage and decreased office-holding requirements. Furthermore, extensive campaigning provided an opportunity for voters and non-voters, including women, to participate in the political process. Despite these changes, elites continued to occupy the main positions of power. Though elites served in state government and as party leaders, I contend that political power remained in the hands of their constituents throughout the antebellum period

Dissection of Saccharomyces Cerevisiae Asci

Yeast is a highly tractable model system that is used to study many different cellular processes. The common laboratory strain Saccharomyces cerevisiae exists in either a haploid or diploid state. The ability to combine alleles from two haploids and the ability to introduce modifications to the genome requires the production and dissection of asci. Asci production from haploid cells begins with the mating of two yeast haploid strains with compatible mating types to produce a diploid strain. This can be accomplished in a number of ways either on solid medium or in liquid. It is advantageous to select for the diploids in medium that selectively promotes their growth compared to either of the haploid strains. The diploids are then allowed to sporulate on nutrient-poor medium to form asci, a bundle of four haploid daughter cells resulting from meiotic reproduction of the diploid. A mixture of vegetative cells and asci is then treated with the enzyme zymolyase to digest away the membrane sac surrounding the ascospores of the asci. Using micromanipulation with a microneedle under a dissection microscope one can pick up individual asci and separate and relocate the four ascopores. Dissected asci are grown for several days and tested for the markers or alleles of interest by replica plating onto appropriate selective media

SchussenAktivplus: reduction of micropollutants and of potentially pathogenic bacteria for further water quality improvement of the river Schussen, a tributary of Lake Constance, Germany

The project focuses on the efficiency of combined technologies to reduce the release of micropollutants and bacteria into surface waters via sewage treatment plants of different size and via stormwater overflow basins of different types. As a model river in a highly populated catchment area, the river Schussen and, as a control, the river Argen, two tributaries of Lake Constance, Southern Germany, are under investigation in this project. The efficiency of the different cleaning technologies is monitored by a wide range of exposure and effect analyses including chemical and microbiological techniques as well as effect studies ranging from molecules to communities

The SMS domain of Trs23p is responsible for the in vitro appearance of the TRAPP I complex in Saccharomyces cerevisiae

Saccharomyces cerevisiae transport protein particle (TRAPP) is a family of related multisubunit complexes required for endoplasmic reticulum-to-Golgi transport (TRAPP I), endosome-to-Golgi transport (TRAPP II) or cytosol to vacuole targeting (TRAPP III). To gain insight into the relationship between these complexes, we generated random and targeted mutations in the Trs23p core subunit. Remarkably, at physiological salt concentrations only two peaks (TRAPP I and a high molecular weight peak) are detected in wild-type cells. As the salt was raised, the high molecular weight peak resolved into TRAPP II and III peaks. Deletion of a Saccharomycotina-specific domain of Trs23p resulted in destabilization of TRAPP I but had no effect on TRAPP II or III. This mutation had no observable growth phenotype, normal levels of Ypt1p-directed guanine nucleotide exchange factor activity in vivo and did not display any in vivo nor in vitro blocks in membrane traffic. Biochemical analysis indicated that TRAPP I could be produced from the TRAPP II/III peak in vitro by increasing the salt concentration. Our data suggest that the SMS domain of Trs23p is responsible for the in vitro appearance of TRAPP I in S. cerevisiae. The implications of these findings are discussed

Dynamic, adaptive changes in MAO-A binding after alterations in substrate availability: an in vivo [11C]-harmine positron emission tomography study

Monoamine oxidase A (MAO-A) is an important target in the pathophysiology and therapeutics of major depressive disorder, aggression, and neurodegenerative conditions. We measured the effect of changes in MAO-A substrate on MAO-A binding in regions implicated in affective and neurodegenerative disease with [11C]-harmine positron emission tomography in healthy volunteers. Monoamine oxidase A VT, an index of MAO-A density, was decreased (mean: 14%±9%) following tryptophan depletion in prefrontal cortex (P<0.031), and elevated (mean: 17%±11%) in striatum following carbidopa–levodopa administration (P<0.007). These findings suggest an adaptive role for MAO-A in maintaining monoamine neurotransmitter homeostasis by rapidly compensating fluctuating monoamine levels

Patterned photostimulation via visible-wavelength photonic probes for deep brain optogenetics

Optogenetic methods developed over the past decade enable unprecedented optical activation and silencing of specific neuronal cell types. However, light scattering in neural tissue precludes illuminating areas deep within the brain via free-space optics; this has impeded employing optogenetics universally. Here, we report an approach surmounting this significant limitation. We realize implantable, ultranarrow, silicon-based photonic probes enabling the delivery of complex illumination patterns deep within brain tissue. Our approach combines methods from integrated nanophotonics and microelectromechanical systems, to yield photonic probes that are robust, scalable, and readily producible en masse. Their minute cross sections minimize tissue displacement upon probe implantation. We functionally validate one probe design in vivo with mice expressing channelrhodopsin-2. Highly local optogenetic neural activation is demonstrated by recording the induced response—both by extracellular electrical recordings in the hippocampus and by two-photon functional imaging in the cortex of mice coexpressing GCaMP6