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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., Competing Interests: The authors declare no conflict of interest.

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.

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.

The course-based research experience (CRE) with its documented educational benefits is increasingly being implemented in science, technology, engineering, and mathematics education. This article reports on a study that was done over a period of 3 years to explicate the instructional processes involved in teaching an undergraduate CRE. One hundred and two instructors from the established and large multi-institutional SEA-PHAGES program were surveyed for their understanding of the aims and practices of CRE teaching. This was followed by large-scale feedback sessions with the cohort of instructors at the annual SEA Faculty Meeting and subsequently with a small focus group of expert CRE instructors. Using a qualitative content analysis approach, the survey data were analyzed for the aims of inquiry instruction and pedagogical practices used to achieve these goals. The results characterize CRE inquiry teaching as involving three instructional models: 1) being a scientist and generating data; 2) teaching procedural knowledge; and 3) fostering project ownership. Each of these models is explicated and visualized in terms of the specific pedagogical practices and their relationships. The models present a complex picture of the ways in which CRE instruction is conducted on a daily basis and can inform instructors and institutions new to CRE teaching.

Two temperate mycobacteriophages, Dallas and Jonghyun, were isolated from soil in Washington, DC, using the bacterial host Mycobacterium smegmatis mc 2 155. 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.

The bacteriophage population is vast, dynamic, old, and genetically diverse. The genomics of phages that infect bacterial hosts in the phylum Actinobacteria show them to not only be diverse but also pervasively mosaic, and replete with genes of unknown function. To further explore this broad group of bacteriophages, we describe here the isolation and genomic characterization of 116 phages that infect Microbacterium spp. Most of the phages are lytic, and can be grouped into twelve clusters according to their overall relatedness; seven of the phages are singletons with no close relatives. Genome sizes vary from 17.3 kbp to 97.7 kbp, and their G+C% content ranges from 51.4% to 71.4%, compared to ~67% for their Microbacterium hosts. The phages were isolated on five different Microbacterium species, but typically do not efficiently infect strains beyond the one on which they were isolated. These Microbacterium phages contain many novel features, including very large viral genes (13.5 kbp) and unusual fusions of structural proteins, including a fusion of VIP2 toxin and a MuF-like protein into a single gene. These phages and their genetic components such as integration systems, recombineering tools, and phage-mediated delivery systems, will be useful resources for advancing Microbacterium genetics., Competing Interests: The authors have declared that no competing interests exist.

The large secreted glycoprotein thrombospondin-1 is a potent inhibitor of neovascularization in 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 neovascularization in 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.

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-1 and are missing in thrombospondin-5/COMP could contribute to this activity.

Despite their familiar sensitivity to transformation by dominant-acting ras oncogenes, NIH/3T3 cells carry a ras suppressor. When tested by cell fusion they were able to suppress the anchorage-independent phenotype of both mouse and human cells transformed by activated H-ras or N-ras. This suppression occurred without a decrease in expression of the activated ras oncogene. Ras-transformed NIH/3T3 clones cured of their oncogene by benzamide treatment reverted to a nontransformed phenotype, but had lost the ability to suppress other ras transformants, indicating that their initial transformation was accompanied by suppressor loss. In hamster cells an active ras oncogene increased the rate of chromosome segregation by > 100-fold. These results suggest that in vitro transformation of NIH/3T3 cells by ras may be more similar to multistep in vivo tumor development than previously suspected, involving not only expression of an active oncogene but also loss of a suppressor activity, perhaps induced by the clastogenic oncogene.

The ability of diagnostic pulsed ultrasound to induce heritable genetic damage of the type that could result in neoplasia was assayed using BHK21/cl 13 hamster cells or normal human fibroblasts as targets. Using an exposure apparatus carefully designed to minimize beam attenuation and reflection, cavitation, and heating, cells were exposed from 20 seconds to 40 minutes either to clinical machines operating at maximum power, or to a highly focused nonclinical transducer at 2900 W/cm2, or to 200 shocks from a lithotripter. No evidence of an increase in the frequency of neoplastically transformed BHK cells or in the frequency of mutant human cells was seen over those found in matched sham-exposed controls.

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.