Comparison of ESBL – And AmpC Producing Enterobacteriaceae and Methicillin-Resistant Staphylococcus aureus (MRSA) Isolated from Migratory and Resident Population of Rooks (Corvus frugilegus) in Austria

In order to test whether rooks (Corvus frugilegus) represent good indicators for the potential circulation of antibiotics in their native habitat, two populations with different migratory behavior were tested for the presence of beta-lactamase producing Enterobacteriaceae and methicillin-resistant Staphylococcus aureus (MRSA). In all, 54 and 102 samples of fresh feces of a migratory and a resident population were investigated. A total of 24 and 3 cefotaxime-resistant enterobacterial isolates were obtained from the migratory and resident population, respectively. In these isolates CTX-M-1 (n = 15), CTX-M-3 (n = 3), and CTX-M-15 (n = 3) genes were detected. TEM-1 and OXA-1 were associated with CTX-M in 3 and 2 isolates, respectively. In two E. coli isolates CMY-2 could be detected, where from one isolate displayed an overexpression of chromosomal AmpC as well. Among E. coli isolates the most common phylogenetic group was A (n = 11) and ST1683 (n = 5). In one E. coli of B2-ST131 the rfbO25b locus was detected. Three Enterobacter isolates were stably derepressed AmpC-producers. In five samples of the migratory population, PVL positive MRSA could be isolated. Two isolates were typed SCCmec IVa, spa type t127, and ST1. Three isolates carried a SCCmec type IVc, with spa type t852 and ST22. The highly significant difference of the occurrence of antibiotic resistance between the migratory population from eastern Europe compared to resident population in our study indicates that rooks may be good indicator species for the evaluation of environmental contamination with antibiotic resistant bacteria, especially due to their ecology, foraging behavior and differing migratory behavior.     

Hydrocarbon-metabolizing activity of various mammalian cells in culture

Summary Two methods for determining the hydrocarbon-metabolizing enzyme activity of cultured mammalian cells were compared. The method designed to measure benzo[a]an-thracene-induced aryl hydrocarbon hydroxylase activity could detect and quantify enzyme activities in low passage rodent cells, but could not reproducibly detect levels in intermediate or high passage mouse, rat, or human cells. The method designed to measure the ability of a cell to convert benzo[a]pyrene from an organic-soluble to an aqueous acetone-soluble form proved to be more reproducible. This technique, when modified, was demonstrated to be an effective screening test for the detection of those lines with higher levels of hydrocarbon-metabolizing enzymes. Supported by the Council for Tobacco Research and Contract NIH 70-2068 within the Virus Cancer Program, National Cancer Institute, National Institutes of Health.     

Ontogeny of the proventitious epicormic buds in Quercus petraea.

In the present work, we described the fate of proventitious epicormic buds on the trunks of 40-year-old Quercus petraea trees and in parallel the vascular trace they produced in the wood. Our results show that small and large individual epicormic buds can survive as buds for 40 years and that both are composed of a terminal meristem and scales. Meristematic areas are detected in the scale axils of small buds; in addition to these meristems the large buds also have secondary bud primordia. The small buds are connected to the pith of the main stem by a unique trace, whereas the large buds are connected by one or multiple traces. A single trace might imply that the whole bud is still alive and multiple traces might indicate that the terminal meristem has died. In the latter case, each trace is connected to a secondary bud of the large bud. The buds found in a cluster are composed of a terminal meristem and scales with axillary meristems in the scale axils. A cluster is connected to the pith of a stem either by a unique trace when it seems to be the result of partial abscission of an epicormic shoot or multiple traces when it might have originated from an epicormic bud in which the terminal meristem has died. Whatever the type of the bud, the vascular trace in the bark is composed of a cambium, secondary xylem and parenchyma cells and the trace present in the wood had parenchyma cells with vestiges of secondary xylem. Each year, the vascular trace should be produced in the bark by the cambium of the tree but not by the bud itself. On 40-year-old Q. petraea, we observed a proliferation of epicormic buds and in parallel a multiplication of the number of vascular traces in the trunk, but the knots caused by the traces of epicormic buds in the wood, either as individuals or in clusters, are minor since their colours are only slightly darker than those of woody rays and they are less than 2 mm in diameter. The knots will appear when epicormic buds develop into shoots. Received: 30 March 1999 / Accepted: 09 June 1999     

Cell adhesion molecule in the hexactinellid Aphrocallistes vastus

Abstract. The Hexactinellida sponge Aphrocallistes vastus contains a soluble aggregation factor (AF) whose purification has been described in this communication. It is characterized by a S°_20.w value of 37 and a buoyant density of 1.45 g/cm³. The AF is a glycoporteinaceous particle composed of three major protein species; no core structure could be visualized. In the presence of Ca²⁺, the AF causes secondary aggregation of single cells. The aggregation process is temperature, pH, and ionic strength independent within a broad range. Evidence is presented indicating that two (or more) AF molecules are required for the establishment of a stable cell: cell interaction. In contrast to the AFs from demosponges, the hexactinellid AF functions species-unspecifically.     

Intima-Media Thickness Does Not Differ between Two Common Carotid Artery Segments in Children

Carotid intima-media thickness (cIMT) is a surrogate marker of early atherosclerotic changes in children. cIMT-studies are hard to compare, due to variations in ultrasound protocols, especially regarding the common carotid artery (CCA) segment measured in relation to the bulb. This study’s purpose was therefore to compare two distinct CCA segments in children, to see if cIMT values differ substantially according to the site of measurement. cIMT was assessed after power calculation in 30 children (15 girls) aged 8–17, using B-Mode ultrasound (5–13 MHz) at two CCA locations. The first measurement was performed over a distance of 1 cm immediately after the bulb (A), the second 1cm proximal the bulb (B) over the same distance of 1cm length. Means of end-diastolic far wall cIMT were compared between measurement A and B. cIMT in 30 participants was 0.51±0.06 mm for measurement A and 0.51±0.05 mm for measurement B. Results did not differ significantly (p = .947) over a distance of 2 cm after the bulb. According to our results, studies measuring CCA IMT within the first 2 cm, either close to the bulb or further proximal, can be compared. This will improve interpretation of data and application of reference values.     

Glioma IL13Rα2 Is Associated with Mesenchymal Signature Gene Expression and Poor Patient Prognosis

A major challenge for successful immunotherapy against glioma is the identification and characterization of validated targets. We have taken a bioinformatics approach towards understanding the biological context of IL-13 receptor α2 (IL13Rα2) expression in brain tumors, and its functional significance for patient survival. Querying multiple gene expression databases, we show that IL13Rα2 expression increases with glioma malignancy grade, and expression for high-grade tumors is bimodal, with approximately 58% of WHO grade IV gliomas over-expressing this receptor. By several measures, IL13Rα2 expression in patient samples and low-passage primary glioma lines most consistently correlates with the expression of signature genes defining mesenchymal subclass tumors and negatively correlates with proneural signature genes as defined by two studies. Positive associations were also noted with proliferative signature genes, whereas no consistent associations were found with either classical or neural signature genes. Probing the potential functional consequences of this mesenchymal association through IPA analysis suggests that IL13Rα2 expression is associated with activation of proinflammatory and immune pathways characteristic of mesenchymal subclass tumors. In addition, survival analyses indicate that IL13Rα2 over-expression is associated with poor patient prognosis, a single gene correlation ranking IL13Rα2 in the top ~1% of total gene expression probes with regard to survival association with WHO IV gliomas. This study better defines the functional consequences of IL13Rα2 expression by demonstrating association with mesenchymal signature gene expression and poor patient prognosis. It thus highlights the utility of IL13Rα2 as a therapeutic target, and helps define patient populations most likely to respond to immunotherapy in present and future clinical trials.     

Structure function relationships for the IL 2 receptor system. III. Tac protein missing amino acids 102 to 173 (exon 4) is unable to bind IL 2: detection of spliced protein after L cell transfection

High affinity receptors for interleukin 2 (IL 2) contain the Tac protein as one ligand-binding subunit. Localization of the IL 2-binding site on this molecule, as well as localization of the complementary site on IL 2, should provide insight into the design of IL 2 analogs. In this report, we examine the ability of normal and modified Tac protein to bind IL 2 and several antibodies that recognize the native Tac molecule. Using a transient L cell expression system, we have determined that transfection with cDNA-missing Tac exon 4 resulted in expression of spliced protein that had no measurable binding to IL 2 or the monoclonal anti-receptor antibodies, anti-Tac, and 7G7/B6. This protein was detected, however, by rabbit polyclonal antibodies prepared against synthetic Tac peptides. Thus, one or more amino acids encoded by exon 4 is important, either for direct ligand contact or for the proper folding of critical segments of the Tac molecule. In addition, insertion of stop codons at a unique restriction enzyme site near the beginning of exon 5 resulted in cellular secretion of truncated Tac molecules that were capable of binding IL 2, anti-Tac, and 7G7/B6. Amino acids encoded by exons 5 to 8 thus play no critical role in IL 2 binding. The ligand association demonstrated for truncated Tac protein produced by exons 2 to 4 should guide attempts to define the IL 2-binding segment of the Tac molecule.     

The maize autonomous element Activator (Ac) shows a minimal germinal excision frequency of 0.2%–0.5% in transgenic Arabidopsis thaliana plants

Summary The autonomous mobile element Activator from Zea mays was introduced into Arabidopsis thaliana via Agrobacterium-mediated gene transfer. The use of a chimaeric construct, where the Ac element is located in the leader of the neomycin phosphotransferase (NPT II) gene, enabled the excision of Ac to be monitored by assaying for the reconstitution of NPT II gene activity. Using this approach, the transpositional activity of AC was initially studied in primary transformants. About 50% of the regenerating Ac transformants showed evidence for excision of the element. Reintegration of Ac was confirmed by Southern blot analysis. Transposition events are transmitted to the F1 generation with a minimal frequency of 0.3%. In a few exceptional cases they are detected in a high proportion of the F1 generation. Seedlings from the F2 and F3 generations were assayed for the rate of germinal excisions by scoring for kanamycin resistance. The minimal frequency of germinal excision events amounts to 0.2%–0.5% and hence allows the use of the Ac element for gene tagging purposes in A. thaliana.