Efficient targeting to storage granules of human proinsulins with altered propeptide domain.

In neuronal and endocrine cells, peptide hormones are selectively segregated into storage granules, while other proteins are exported continuously without storage. Sorting of hormones by cellular machinery involves the recognition of specific structural domains on prohormone molecules. Since the propeptide of insulin is known to play an important role in its three-dimensional structure, it is reasonable to speculate that targeting of proinsulin to storage granules would require a functional connecting peptide. To test this hypothesis, we constructed two mutations in human proinsulin with different predicted structures. In one mutation, Ins delta C, the entire C peptide was deleted, resulting in an altered insulin in which the B and the A chains are joined contiguously. In the other mutation, Ins/IGF, the C peptide of proinsulin was replaced with the unrelated 12-amino acid connecting peptide of human insulin-like growth factor-I; this substitution should permit correct folding of the B and A chains to form a tertiary structure similar to that of proinsulin. By several biochemical and morphological criteria, we found that Ins/IGF is efficiently targeted to storage granules, suggesting that the C peptide of proinsulin does not contain necessary sorting information. Unexpectedly, Ins delta C, which presumably cannot fold properly, is also targeted to granules at a high efficiency. These results imply that either the targeting machinery can tolerate changes in the tertiary structure of transported proteins, or that the B and A chains of insulin can form a relatively intact three-dimensional structure even in the absence of C peptide

Egyenesszárnyú rovarok akusztikus szignáljainak elemzése és a fajspecifikus párfelismerésben betöltött szerepük kísérletes vizsgálata = Descriptive analyses of Orthopteran acoustic signals and experiments on their function in the species-specific mate-recognition system

Két kérdéskörben végeztem vizsgáltaimat. Az első kérdéskörben a tudomány számára még ismeretlen énekű taxonok vagy taxonómiai szempontból érdekes helyzetű populációk hangjeleinek leíró analízisével foglalkoztam. Ebben a témakörben az Isophya harzi, I. rectipennis, I. zubowskii, I. modesta longicauda, I. pienensis, Saga rammei és Poecilimon brunneri akusztikus szignáljait elemeztem. A hangelemzési eredmények támogatják a vizsgált taxonok jelenleg érvényes taxonómiai státuszát, és nagymértékben megkönnyítik a rokonsági körükbe tartozó példányok faji identifikációját. Két tudományra új, morfológiailag kriptikus Isophya fajt sikerült Romániában felfedezni, valamint hazánk illetve Románia faunájára 1-1 új egyenesszárnyú fajt sikerült kimutatni. A második kérdéskörben a fajspecifikus párfelismerés szempontjából kritikus énekjellemzők felderítésével foglalkoztam. Ebben a kérdéskörben az Isophya camptoxypha nőstényeinek énekpreferenciait vizsgáltam hangvisszajátszásos kísérletek során a hímek énekének két ritmikai jellemzőjével szemben. A nőstények a hím syllabusainak időtartamával és ismétlési periódusával szemben is unimodális preferenciát mutattak. A két énekparaméter terében a szimpatrikus fajok énekei közül a mért nőstény ének-preferenciagörbék egyértelműen kiválasztják az I. camptoxypha hímek énekét. Ezek alapján a vizsgált két karakter és a velük szembeni nőstény preferenciák hatékony komponensei lehetnek az I. camptoxypha párfelismerési rendszerének. | My work was focused on two areas of the bioacoustics of Orthoptera. In a first group of studies I described the previously unknown acoustic signals of the following species, subspecies or populations from Eastern Europe: Isophya harzi, I. rectipennis, I. zubowskii, I. modesta longicauda, I. pienensis, Saga rammei and Poecilimon brunneri. The results confirm the present taxonomic status of all the studied taxa and makes the identification of specimens more confident and easier. Two morphologically criptic species of Isophya have been discovered in Rumania which are new to scinence, and also faunistic records for one species new to the Hungarian fauna and one species new to the Rumanian fauna have been made. An other area of my research was to examine the funciton of certain acoustic parameters of the male song in the species recognition of females. Female preferences for two male song characters (duration of syllables [DS], syllable repetition period [SRP]) have been studied in Isophya camptoxypha. Songs with modified DS or SRP were presented to virgin females and their response songs were recorded and counted. Female preference functions were unimodal for both characters. A comparison between the obtained preference functions and the DS and SRP values measured in I. camptoxypha and sympatric Isophya species suggests that the two examined characters and female preferences for them may be effective components of the species-specific mate recognition system of I. camptoxypha

The Development Of A Consensus Management By Objectives Model And A Comparison To The Clark County School District Management And Accountability System For Secondary Schools

The purpose of the study was to examine selected business and education management by objectives (MBO) models and identify the common elements. These elements resulted in a consensus MBO model which was compared to determine agreement with the Clark County School District\u27s Management and Accountability System for Secondary Schools. Educational accountability, the theoretical bases for MBO and MBO models in business and education were treated in the review of the literature. Graphic models developed in the study included the Clark County District\u27s Management and Accountability System for Secondary Schools and a consensus MBO model; A management process based on the principles of management by objectives derived from the business world was reported as a suitable means for managing schools and communicating results to the public. The importance of people to an organization was judged as critical. MBO provided a means to deal effectively with people on a professional and productive basis while accomplishing the goals and objectives of the organization

Sorting Ourselves Out: Seeking Consensus on Trafficking in the Beta-Cell

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74967/1/j.1600-0854.2004.00152.x.pd

Short Versus Long Roux-Limb Length in Roux-en-Y Gastric Bypass Surgery for the Treatment of Morbid and Super Obesity: a Systematic Review of the Literature

Because of an important burden of disease, obesity is a major public health challenge in the twenty-first century. Where medico-psychological management has shown its limitations, bariatric surgery is now acknowledged as the most efficient therapy potentially offered to severely obese patients. Among other options, Roux-en-Y gastric bypass (RYGBP) is the most frequently performed procedure. The objective of this review is to systematically evaluate the effect of the Roux- (alimentary) limb length on postoperative weight loss after RYGBP in severely obese patients. MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched using terms related to Roux-limb, gastric bypass and obesity. To be included, studies had to be either randomized controlled trials, quasi-randomized controlled trials or prospective cohort studies comparing a shorter to a longer Roux-limb. Studies were critically appraised with regard to methodological components. Eight studies were reviewed. Variations in methodology, operation design and outcome assessment among studies caused considerable clinical heterogeneity, preventing us from performing a meta-analysis. The overall quality was questionable, owing to lack of rigor in methodological components reporting. Results were heterogeneous, but we identified a trend supporting that the construction of a longer Roux-limb is more efficient in super obese patients. This review suggests that the tailoring of a longer Roux-limb might only be efficient in super obese patients. The overall limited quality of the included studies prompts to call for improvement in trial design in surger

Architecture of coatomer: Molecular characterization of delta-COP and protein interactions within the complex

Copyright © 2011 by The Rockefeller University Press.Coatomer is a cytosolic protein complex that forms the coat of COP I-coated transport vesicles. In our attempt to analyze the physical and functional interactions between its seven subunits (coat proteins, [COPs] alpha-zeta), we engaged in a program to clone and characterize the individual coatomer subunits. We have now cloned, sequenced, and overexpressed bovine alpha-COP, the 135-kD subunit of coatomer as well as delta-COP, the 57-kD subunit and have identified a yeast homolog of delta-COP by cDNA sequence comparison and by NH2-terminal peptide sequencing. delta-COP shows homologies to subunits of the clathrin adaptor complexes AP1 and AP2. We show that in Golgi-enriched membrane fractions, the protein is predominantly found in COP I-coated transport vesicles and in the budding regions of the Golgi membranes. A knock-out of the delta-COP gene in yeast is lethal. Immunoprecipitation, as well as analysis exploiting the two-hybrid system in a complete COP screen, showed physical interactions between alpha- and epsilon-COPs and between beta- and delta-COPs. Moreover, the two-hybrid system indicates interactions between gamma- and zeta-COPs as well as between alpha- and beta' COPs. We propose that these interactions reflect in vivo associations of those subunits and thus play a functional role in the assembly of coatomer and/or serve to maintain the molecular architecture of the complex.This work was supported by The Deutsche Forschungsgemeinschaft (SFB 352), the Human Frontier Science Program, and the Swiss National Science Foundation No. 31-43366.95

Isolation of EpH4 mammary epithelial cell subpopulations which differ in their morphogenetic properties

Summary: EpH4 is a nontumorigenic cell line derived from spontaneously immortalized mouse mammary gland epithelial cells (Fialka et al., 1996). When grown in collagen gels, EpH4 cells give rise to different types of structures, e.g., solid cords or branching tubes. By removing and subsequently dissociating single three-dimensional colonies of defined morphology, we have isolated six clonal subpopulations of EpH4 cells which display distinct morphogenetic properties in collagen gel cultures. Thus, cells from the H1B clone form branching cords devoid of a central lumen, K3A3 cells from cords enclosing small multifocal lumina, and J3B1 cells form large cavitary structures containing a wide lumen. I3G2 cells form either cords or tubes, depending on the type of serum added to the culture medium. Finally, when grown in serum-free medium, Be1a cells form spherical cysts, whereas Be4a cells form long, extensively branched tubes. In additional assays of morphogenesis, i.e., cell sandwiching between two collagen gels or culture on a thick layer of Matrigel (a laminin-rich extracellular matrix), all clones form epithelial-cell-lined cavitary structures, except H1B cells which are unable to generate lumina under these conditions. The EpH4 sublines we have isolated provide an in vitro system for studying the mechanisms responsible for lumen formation and branching morphogenesis, as well as for identifying the factors which subvert these developmental processes during mammary carcinogenesi

Expression and function of alpha(v)beta(3) and alpha(v)beta(5) integrins in the developing pancreas: roles in the adhesion and migration of putative endocrine progenitor cells.

Cell-cell and cell-matrix interactions play a critical role in tissue morphogenesis and in homeostasis of adult tissues. The integrin family of adhesion receptors regulates cellular interactions with the extracellular matrix, which provides three-dimensional information for tissue organization. It is currently thought that pancreatic islet cells develop from undifferentiated progenitors residing within the ductal epithelium of the fetal pancreas. This process involves cell budding from the duct, migration into the surrounding mesenchyme, differentiation, and clustering into the highly organized islet of Langerhans. Here we report that alpha(v)beta(3) and alpha(v)beta(5), two integrins known to coordinate epithelial cell adhesion and movement, are expressed in pancreatic ductal cells and clusters of undifferentiated cells emerging from the ductal epithelium. We show that expression and function of alpha(v)beta(3) and alpha(v)beta(5) integrins are developmentally regulated during pancreatic islet ontogeny, and mediate adhesion and migration of putative endocrine progenitor cells both in vitro and in vivo in a model of pancreatic islet development. Moreover, we demonstrate the expression of fibronectin and collagen IV in the basal membrane of pancreatic ducts and of cell clusters budding from the ductal epithelium. Conversely, expression of vitronectin marks a population of epithelial cells adjacent to, or emerging from, pancreatic ducts. Thus, these data provide the first evidence for the contribution of integrins alpha(v)beta(3) and alpha(v)beta(5) and their ligands to morphogenetic events in the human endocrine pancreas