We isolated three mycobacteriophages that belong to cluster S, namely, Beelzebub, Raela, and RedRaider77. Annotation revealed a genome structure typical of cluster S phages, including an atypical ...location of two minor tail protein genes in the right arm of these viral genomes.
ABSTRACT
We purified two novel bacteriophages from soil collected in Sioux County, Iowa: BAjuniper and Tedro. These bacteriophages were isolated from the host,
Microbacterium foliorum
. BAjuniper was ...assigned to cluster EB, and Tedro was assigned to cluster EF. Both phages display genomes typical of other phages in their clusters.
Bacteriophages Clayda5, Gshelby23, Wrigley, and Santhid were isolated from soil samples collected in Iowa, with genomes typical of actinobacteriophages from clusters EB, EM, CY, and DY, respectively. ...Wrigley and Santhid were isolated on Gordonia terrae and are likely to be temperate. Clayda5 and Gshelby23 were isolated on Microbacterium foliorum.
Two temperate mycobacteriophages, Dallas and Jonghyun, were isolated from soil in Washington, DC, using the bacterial host Mycobacterium smegmatis mc
155. Analysis of the genomes revealed that Dallas ...and Jonghyun belong to clusters J and G, respectively. The structures of the genomes are typical of their respective clusters.
Thrombospondin-1 (TSP1) is a large modular matrix protein containing three identical disulfide-linked 180-kD chains that inhibits neovascularization in vivo (Good et al., 1990). To determine which of ...the structural motifs present in the 180-kD TSP1 polypeptide mediate the anti-angiogenic activity, a series of protease-generated fragments were tested using several in vitro and in vivo assays that reflect angiogenic activity. The majority of the anti-angiogenic activity of TSP1 resides in the central 70-kD stalk region which alone could block neovascularization induced by bFGF in the rat cornea in vivo and inhibit both migration in a modified Boyden chamber and 3Hthymidine incorporation stimulated by bFGF in cultured capillary endothelial cells. Although TSP1 has been shown to bind active TGFβ1, this cytokine could not account for the inhibitory effects of the stalk region of TSP1 on cultured endothelial cells. Peptides and truncated molecules were used to further localize inhibitory activity to two domains of the central stalk, the procollagen homology region and the properdin-like type 1 repeats. Trimeric recombinant TSP1 containing NH2-terminal sequences truncated after the procollagen-like module inhibited endothelial cell migration in vitro and corneal neovascularization in vivo whereas trimeric molecules truncated before this domain were inactive as was the NH2-terminal heparin-binding domain that is present in both recombinant molecules. A series of peptides from the procollagen-like region, the smallest of which consisted of residues 303-309 of TSP1, inhibited angiogenesis in vivo in the rat cornea and the migration of endothelial cells in vitro. A 19-residue peptide containing these sequences blocked vessel formation in the granulation tissue invading a polyvinyl sponge implanted into the mouse. Nineteen residue peptides derived from two of the three type 1 repeats present in the intact TSP1 molecule blocked neovascularization in vivo in the rat cornea and inhibited the migration of cultured endothelial cells with ED50's of 0.6-7 μM. One of these peptides, containing residues 481-499 of TSP1, also inhibited vessel formation in granulation tissue invading sponges in vivo. These results suggest that the large TSP1 molecule employs at least two different structural domains and perhaps two different mechanisms to accomplish a single physiological function, the inhibition of neovascularization. The definition of short peptides from each of these domains that are able to block the angiogenic process may be of use in designing targeted inhibitors of the pathological neovascularization that underlies many diseases.
The large secreted glycoprotein thrombospondin-1 is a potent inhibitor of neovascularizationin vivo.In order to better understand its mechanism of action, we have determined the full range of ...deficits thrombospondin can impose on cultured capillary endothelial cells. Exogenously added thrombospondin-1 blocked the ability of these cells to organize into cords. It blocked the migration of endothelial cells and vascular smooth muscle cells, but not that of fibroblasts, neutrophils, or keratinocytes, demonstrating specificity. Conversely, when the endogenous thrombospondin-1 produced by the endothelial cells was inactivated using antibodies that can neutralize its inhibition of neovascularizationin vivo,migration toward basic fibroblast growth factor and cord formation were stimulated, and sparsely plated cells developed cylindrical cavities. These cavities formed by vesicle fusion, extended the depth of the cell, and appeared to be incipient lumens, staining positively for the luminal marker angiotensin converting enzyme. Antiangiogenic levels of thrombospondin-1 had no measurable effect on the overall level of activity of soluble gelatinases or on urokinase plasminogen activator produced by activated endothelial cells. Coupled with previously published data, these results demonstrate thrombospondin-1 is a multifaceted inhibitor able to block the entire program of dedifferentiation and redifferentiation essential to the formation of new vessels. They also support the contention that the endogenously produced protein contributes to the quiescence of the normal vasculature.
Course-based research pedagogy involves positioning students as contributors to authentic research projects as part of an engaging educational experience that promotes their learning and persistence ...in science. To develop a model for assessing and grading students engaged in this type of learning experience, the assessment aims and practices of a community of experienced course-based research instructors were collected and analyzed. This approach defines four aims of course-based research assessment—(1) Assessing Laboratory Work and Scientific Thinking; (2) Evaluating Mastery of Concepts, Quantitative Thinking and Skills; (3) Appraising Forms of Scientific Communication; and (4) Metacognition of Learning—along with a set of practices for each aim. These aims and practices of assessment were then integrated with previously developed models of course-based research instruction to reveal an assessment program in which instructors provide extensive feedback to support productive student engagement in research while grading those aspects of research that are necessary for the student to succeed. Assessment conducted in this way delicately balances the need to facilitate students’ ongoing research with the requirement of a final grade without undercutting the important aims of a CRE education.
Inhibition of Angiogenesis by Thrombospondin-2 Volpert, O.V.; Tolsma, S.S.; Pellerin, S. ...
Biochemical and biophysical research communications,
12/1995, Letnik:
217, Številka:
1
Journal Article
Recenzirano
To assess the ability of proteins of the thrombospondin family to inhibit angiogenesis, recombinant murine thrombospondin-2, bovine thrombospondin-2/CISP and thrombospondin-5/COMP were purified and ...tested for ability to block the migration of capillary endothelial cells towards a variety of inducers and to inhibit neovascularization induced in the rat cornea. Both preparations of thrombospondin-2 were active inhibitors in vitro and in vivo whereas thrombospondin-5/COMP was inactive. These results define thrombospondin-2 as a newly identified naturally occurring inhibitor of angiogenesis and suggest that the properdin-like type 1 modules that it shares with antiangiogenic thrombospondin-l and are missing in thrombospondin-5/COMP could contribute to this activity.
Tetraploid and near-tetraploid chemically transformed derivatives of the pseudodiploid hamster line BHK 21/clone 13 were prepared in four different ways and their ability to be suppressed for ...anchorage independence by fusion to the anchorage-dependent parental line was tested. In all cases the presence of a single normal genome, thought on genetic grounds to contain a single suppressor gene, was able to prevent the anchorage-independent growth of transformed lines whether they contained one or two complements of pseudodiploid chromosomes. Suppression of the single step in carcinogenesis that is registered by BHK cells as they transform to anchorage independence is thus unusually powerful and apparently independent of chromosome balance and of strict dosage effects.
•Organisational characteristics influence giving intentions of (potential) donors.•Overhead costs negatively influence giving intentions of (potential) donors.•(Potential) donors are in favour of ...experienced, familiar organisations.•To donors high in social trust the familiarity of an organisation remains important.•The ideal organisation is a hybrid, rarer type of organisation.
This article investigates what type of international development organisations potential donors would prefer to donate to. We constructed 960 scenarios in which a fictive development organisation was described. The scenarios were randomly varied across eight characteristics of the organisation: size, familiarity, experience, religious character, number of different projects run by the organisation, number of countries in which the organisation is active, overhead costs and staff composition. A large representative sample of the Dutch population (N=2,758) received six randomly allocated scenarios and had to decide if, and if so, how much they would donate to the depicted (fictive) organisation. Results demonstrate that donors have a preference for familiar organisations with several years of experience. Although donors have a strong aversion regarding overhead costs, we find that donors seem to value the capacities of paid staff members and are, to a certain extent, willing to pay a price for these. The ideal development organisation combines features typical of small(er) scale voluntary development organisations (e.g. mainly run by volunteers) and large(r) scale professional organisations (e.g. running development programmes in numerous countries).
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