Gene identification and analysis of transcripts differentially regulated in fracture healing by EST sequencing in the domestic sheep

BACKGROUND: The sheep is an important model animal for testing novel fracture treatments and other medical applications. Despite these medical uses and the well known economic and cultural importance of the sheep, relatively little research has been performed into sheep genetics, and DNA sequences are available for only a small number of sheep genes. RESULTS: In this work we have sequenced over 47 thousand expressed sequence tags (ESTs) from libraries developed from healing bone in a sheep model of fracture healing. These ESTs were clustered with the previously available 10 thousand sheep ESTs to a total of 19087 contigs with an average length of 603 nucleotides. We used the newly identified sequences to develop RT-PCR assays for 78 sheep genes and measured differential expression during the course of fracture healing between days 7 and 42 postfracture. All genes showed significant shifts at one or more time points. 23 of the genes were differentially expressed between postfracture days 7 and 10, which could reflect an important role for these genes for the initiation of osteogenesis. CONCLUSION: The sequences we have identified in this work are a valuable resource for future studies on musculoskeletal healing and regeneration using sheep and represent an important head-start for genomic sequencing projects for Ovis aries, with partial or complete sequences being made available for over 5,800 previously unsequenced sheep genes

In vitro experimental system for analysis of transcription–translation coupling

Transcription and translation are coupled in bacteria, meaning that translation takes place co-transcriptionally. During transcription–translation, both machineries mutually affect each others’ functions, which is important for regulation of gene expression. Analysis of interactions between RNA polymerase (RNAP) and the ribosome, however, are limited due to the lack of an in vitro experimental system. Here, we report the development of an in vitro transcription coupled to translation system assembled from purified components. The system allows controlled stepwise transcription and simultaneous stepwise translation of the nascent RNA, and permits investigation of the interactions of RNAP with the ribosome, as well as the effects of translation on transcription and transcription on translation. As an example of usage of this experimental system, we uncover complex effects of transcription–translation coupling on pausing of transcription

Evolution of a Core Gene Network for Skeletogenesis in Chordates

The skeleton is one of the most important features for the reconstruction of vertebrate phylogeny but few data are available to understand its molecular origin. In mammals the Runt genes are central regulators of skeletogenesis. Runx2 was shown to be essential for osteoblast differentiation, tooth development, and bone formation. Both Runx2 and Runx3 are essential for chondrocyte maturation. Furthermore, Runx2 directly regulates Indian hedgehog expression, a master coordinator of skeletal development. To clarify the correlation of Runt gene evolution and the emergence of cartilage and bone in vertebrates, we cloned the Runt genes from hagfish as representative of jawless fish (MgRunxA, MgRunxB) and from dogfish as representative of jawed cartilaginous fish (ScRunx1–3). According to our phylogenetic reconstruction the stem species of chordates harboured a single Runt gene and thereafter Runt locus duplications occurred during early vertebrate evolution. All newly isolated Runt genes were expressed in cartilage according to quantitative PCR. In situ hybridisation confirmed high MgRunxA expression in hard cartilage of hagfish. In dogfish ScRunx2 and ScRunx3 were expressed in embryonal cartilage whereas all three Runt genes were detected in teeth and placoid scales. In cephalochordates (lancelets) Runt, Hedgehog and SoxE were strongly expressed in the gill bars and expression of Runt and Hedgehog was found in endo- as well as ectodermal cells. Furthermore we demonstrate that the lancelet Runt protein binds to Runt binding sites in the lancelet Hedgehog promoter and regulates its activity. Together, these results suggest that Runt and Hedgehog were part of a core gene network for cartilage formation, which was already active in the gill bars of the common ancestor of cephalochordates and vertebrates and diversified after Runt duplications had occurred during vertebrate evolution. The similarities in expression patterns of Runt genes support the view that teeth and placoid scales evolved from a homologous developmental module

Edge Partitions in Undirected Graphs

Partitions of the set of edges of an undirected graph are investigated in general. The set of vertices of attachment of a partition and the partition of the W-components of a set of vertices are defined. Their properties show a high degree of duality. An algorithm to find the W-components is presented. The results are applied to a proof of Menger's theorem combined with an algorithm for finding maximal sets of vertex-disjoint paths as well as minimal sets of separating vertices

Abundance, diversity and seasonality of adult Trichoptera in and around hydroelectric generating stations along the Winnipeg River

Hydroelectric generating stations along the Winnipeg River are subject to emergence of large numbers of caddisflies which cause work-related allergies. The purpose of this study was to determine peaks in seasonal and nightly flight activity of the most abundant caddisfly species in and around the generating stations and to recommend management practices to alleviate the problems caused by caddisflies. Modified New Jersey light traps were used to capture caddisflies during the 1997 and 1998 field seasons at hydroelectric generating stations at Great Falls and Seven Sisters. The estimated total number of caddisflies caught over the two-year period was 526,607; 275,806 in 1997 and 250,801 in 1998. The caddisflies belonged to 14 families, 35 genera and at least 76 taxa. The caddisfly flight season, from first capture to last, differed by only one week in the two years. In 1997, caddisflies were collected from 1 June to 16 October, and in 1998 from 26 May to 8 October. Peak flight activity occurred one week earlier at Great Falls than at Seven Sisters. In 1997, approximately 75% of caddisflies were captured during the five-week period from the last week of June to the end of July. The peak flight activity in 1998 occurred from mid-June to mid-July (four weeks), when approximately 80% of the yearly total of caddisflies were captured. Peaks in nightly flight activity were seen between 2300 and 0100, when approximately 62% of the nightly total were captured. Large numbers of caddisflies were captured inside the generating stations. To determine the caddisfly mode of entry, four nights were spent in the stations. Through personal observations and the use of emergence traps, it was established that caddisflies enter the buildings through various openings (i.e. broken windows, under doors) and by emergence from the gate openings inside the gate rooms. Insect particulates, including identifiable caddisfly parts, which were blown into the generating stations through the air-cooling system, were also collected in fine nylon filters attached to the turbine caps in the powerhouses. Changes in management practices are required to decrease the exposure of Manitoba Hydro employees to caddisfly particulate. These must include maintaining and improving sanitation practices and increased vigilance to remove or exclude caddisflies from the generating stations

Schlossplatz Münster : Conversion from parking space to urban space : [Wintersemester 2022/2023]

Diese Arbeit kann in der Bibliothek für Architektur, Design und Kunst (Leonardocampus 10) eingesehen werden