β-Glucan is a major growth substrate for human gut bacteria related to Coprococcus eutactus

A clone encoding carboxymethyl cellulase activity was isolated during functional screening of a human gut metagenomic library using Lactococcus lactis MG1363 as heterologous host. The insert carried a glycoside hydrolase family 9 (GH9) catalytic domain with sequence similarity to a gene from Coprococcus eutactus ART55/1. Genome surveys indicated a limited distribution of GH9 domains among dominant human colonic anaerobes. Genomes of C. eutactus-related strains harboured two GH9-encoding and four GH5-encoding genes, but the strains did not appear to degrade cellulose. Instead, they grew well on β-glucans and one of the strains also grew on galactomannan, galactan, glucomannan and starch. Coprococcus comes and Coprococcus catus strains did not harbour GH9 genes and were not able to grow on β-glucans. Gene expression and proteomic analysis of C. eutactus ART55/1 grown on cellobiose, β-glucan and lichenan revealed similar changes in expression in comparison to glucose. On β-glucan and lichenan only, one of the four GH5 genes was strongly upregulated. Growth on glucomannan led to a transcriptional response of many genes, in particular a strong upregulation of glycoside hydrolases involved in mannan degradation. Thus, β-glucans are a major growth substrate for species related to C. eutactus, with glucomannan and galactans alternative substrates for some strains

Exogenously added GPI-anchored tissue inhibitor of matrix metal loproteinase-1 (TIMP-1) displays enhanced and novel biological activities

The family of tissue inhibitors of metalloproteinases (TIMPs) exhibits diverse physiological/biological functions including the inhibition of active matrix metalloproteinases, regulation of proMMP activation, cell growth, and the modulation of angiogenesis. TIMP-1 is a secreted protein that can be detected on the cell surface through its interaction with surface proteins. The diverse biological functions of TIMP-1 are thought to lie, in part, in the kinetics of TIMP-1/MMP/surface protein interactions. Proteins anchored by glycoinositol phospholipids (GPIs), when purified and added to cells in vitro, are incorporated into their surface membranes. A GPI anchor was fused to TIMP-1 to generate a reagent that could be added directly to cell membranes and thus focus defined concentrations of TIMP-1 protein on any cell surface independent of protein-protein interaction. Unlike native TIMP-1, exogenously added GPI-anchored TIMP-1 protein effectively blocked release of MMP-2 and MMP-9 from osteosarcoma cells. TIMP-1-GP1 was a more effective modulator of migration and proliferation than TIMP-1. While control hTIMP-1 protein did not significantly affect migration of primary microvascular endothelial cells at the concentrations tested, the GPI-anchored TIMP-1 protein showed a pronounced suppression of endothelial cell migration in response to bFGF. In addition, TIMP-1-GPI was more effective at inducing microvascular endothelial proliferation. In contrast, fibroblast proliferation was suppressed by the agent. Reagents based on this method should assist in the dissection of the protease cascades and activities involved in TIMP biology. Membrane-fixed TIMP-1 may represent a more effective version of the protein for use in therapeutic expression

Brands in international and multi‐platform expansion strategies: economic and management issues

Powerful media branding has historically facilitated successful international expansion on the part of magazine and other content forms including film and TV formats. Multi-platform expansion is now increasingly central to the strategies of media companies and, as this chapter argues, effective use of branding in order to engage audiences effectively and to secure a prominent presence across digital platforms forms a core part of this. Drawing on original research into the experience of UK media companies, this chapter highlights some of the key economic, management and socio-cultural issues raised by the ever-increasing role of brands and branding in the strategies of international and multi-platform expansion that are increasingly common- place across media

Research on the Geography of Agricultural Change: Redundant or Revitalized?

Future research directions for agricultural geography were the subject of debate in Area in the late 1980s. The subsequent application of political economy ideas undoubtedly revived interest in agricultural research. This paper argues that agricultural geography contains greater diversity than the dominant political economy discourse would suggest. It reviews ‘other’ areas of agricultural research on policy, post-productivism, people, culture and animals, presenting future suggestions for research. They should ensure that agricultural research continues revitalized rather than redundant into the next millennium

Effects of the rainy season on growth of Mimosa tenuiflora in dry tropical forest, Brazil.

Resumo

Chemical Evolution of Galaxies

Chemical evolution of galaxies brings together ideas on stellar evolution and nucleosynthesis with theories of galaxy formation, star formation and galaxy evolution, with all their associated uncertainties. In a new perspective brought about by the Hubble Deep Field and follow-up investigations of global star formation rates, diffuse background etc., it has become necessary to consider the chemical composition of dark baryonic matter as well as that of visible matter in galaxies.Comment: 6 pages, AAS LaTeX macros v5.0, Millennium Essay to appear in PASP, Feb 200

PLISMIP-ANT, an ice-sheet model intercomparison project

In the context of future climate change, understanding the nature and behaviour of ice sheets during warm intervals in Earth history is of fundamental importance. The late Pliocene warm period (also known as the PRISM interval: 3.264 to 3.025 million years before present) can serve as a potential analogue for projected future climates. Although Pliocene ice locations and extents are still poorly constrained, a significant contribution to sea-level rise should be expected from both the Greenland ice sheet and the West and East Antarctic ice sheets based on palaeo sea-level reconstructions. Here, we present results from simulations of the Antarctic ice sheet by means of an international Pliocene Ice Sheet Modeling Intercomparison Project (PLISMIP-ANT). For the experiments, ice-sheet models including the shallow ice and shelf approximations have been used to simulate the complete Antarctic domain (including grounded and floating ice). We compare the performance of six existing numerical ice-sheet models in simulating modern control and Pliocene ice sheets by a suite of five sensitivity experiments. We include an overview of the different ice-sheet models used and how specific model configurations influence the resulting Pliocene Antarctic ice sheet. The six ice-sheet models simulate a comparable present-day ice sheet, considering the models are set up with their own parameter settings. For the Pliocene, the results demonstrate the difficulty of all six models used here to simulate a significant retreat or re-advance of the East Antarctic ice grounding line, which is thought to have happened during the Pliocene for the Wilkes and Aurora basins. The specific sea-level contribution of the Antarctic ice sheet at this point cannot be conclusively determined, whereas improved grounding line physics could be essential for a correct representation of the migration of the grounding-line of the Antarctic ice sheet during the Pliocene

Attitude Change in Response to an In-Service Teacher Education Programme

How can I tell how successful this course has been? is becoming an increasingly common question in tertiary education. This interest in tertiary teaching and learning is reflected in the fact that one-half of all Australian universities now have tertiary teaching units. There are a number of reasons why evaluation is important. Firstly, discrepancies between the actual and the ideal situation can be detected, causes identified and corrective measures instituted at all stages of the evaluative model, to serve the interests of increased efficiency and improved staff and student satisfaction. Secondly, courses which are continually being evaluated are better able to meet changing demands from students, from the society which the educational institution is serving, and also better able to adjust to internal changes in staff numbers and expertise. Thirdly, evaluation properly conducted can provide a statement of accountability

From DNA sequence to application: possibilities and complications

The development of sophisticated genetic tools during the past 15 years have facilitated a tremendous increase of fundamental and application-oriented knowledge of lactic acid bacteria (LAB) and their bacteriophages. This knowledge relates both to the assignments of open reading frames (ORF’s) and the function of non-coding DNA sequences. Comparison of the complete nucleotide sequences of several LAB bacteriophages has revealed that their chromosomes have a fixed, modular structure, each module having a set of genes involved in a specific phase of the bacteriophage life cycle. LAB bacteriophage genes and DNA sequences have been used for the construction of temperature-inducible gene expression systems, gene-integration systems, and bacteriophage defence systems. The function of several LAB open reading frames and transcriptional units have been identified and characterized in detail. Many of these could find practical applications, such as induced lysis of LAB to enhance cheese ripening and re-routing of carbon fluxes for the production of a specific amino acid enantiomer. More knowledge has also become available concerning the function and structure of non-coding DNA positioned at or in the vicinity of promoters. In several cases the mRNA produced from this DNA contains a transcriptional terminator-antiterminator pair, in which the antiterminator can be stabilized either by uncharged tRNA or by interaction with a regulatory protein, thus preventing formation of the terminator so that mRNA elongation can proceed. Evidence has accumulated showing that also in LAB carbon catabolite repression in LAB is mediated by specific DNA elements in the vicinity of promoters governing the transcription of catabolic operons. Although some biological barriers have yet to be solved, the vast body of scientific information presently available allows the construction of tailor-made genetically modified LAB. Today, it appears that societal constraints rather than biological hurdles impede the use of genetically modified LAB.