Synthetic Cassettes for pH-Mediated Sensing, Counting, and Containment.

As pH is fundamental to all biological processes, pH-responsive bacterial genetic circuits enable precise sensing in any environment. Where the unintentional release of engineered bacteria poses a concern, coupling pH sensing to the expression of a toxin creates an effective bacterial containment system. Here, we present a pH-sensitive kill switch (acidic termination of replicating population [acidTRP]), based on the Escherichia coli asr promoter, with a survival ratio of <1 in 10.

Development of Intestinal Scaffolds that Mimic Native Mammalian Intestinal Tissue.

This study is significant because it demonstrates an attempt to design a scaffold specifically for small intestine using a novel fabrication method, resulting in an architecture that resembles intestinal villi. In addition, we use the versatile polymer poly(glycerol sebacate) (PGS) for artificial intestine, which has tunable mechanical and degradation properties that can be harnessed for further fine-tuning of scaffold design. Moreover, the utilization of PGS allows for future development of growth factor and drug delivery from the scaffolds to promote artificial intestine formation.

Rational Design of Evolutionarily Stable Microbial Kill Switches.

The evolutionary stability of synthetic genetic circuits is key to both the understanding and application of genetic control elements. One useful but challenging situation is a switch between life and death depending on environment. Here are presented "essentializer" and "cryodeath" circuits, which act as kill switches in Escherichia coli.

Responses of red-osier dogwood to oil sands tailings treated with gypsum or alum.

The application of composite or consolidated tailings (CT) technology provides Alberta's oil sands industry with a means of reducing the volume of the fines fraction in extraction tailings and allows for faster reclamation and revegetation of mining sites. This study examined the effects of coagulant aids (gypsum and alum), used in the production of CT, on the ion content, growth, and survival of greenhouse-grown red-osier dogwood (Cornus sericea L. subsp.

Comparative diversity and composition of cyanobacteria in three predominant soil crusts of the Colorado Plateau.

Terminal restriction fragment length polymorphism (TRF or T-RFLP) analysis and 16S rDNA sequence analysis from clone libraries were used to examine cyanobacterial diversity in three types of predominant soil crusts in an arid grassland. Total DNA was extracted from cyanobacteria-, lichen-, or moss-dominated crusts that represent different successional stages in crust development, and which contribute different amounts of carbon and nitrogen into the ecosystem. Cyanobacterial 16S rRNA genes were amplified by PCR using cyanobacteria-specific 16S rDNA primers.

Quantitative dot blot analyses of blood-group-related antigens in paired normal and malignant human breast tissues.

Membranes were prepared from 31 breast-cancer specimens and adjacent mammary tissues, dot-blotted to nitrocellulose paper, and reacted with monoclonal antibodies (MAbs) (A, B, Lewis a, Lewis b, sialylated Lewis a, Lewis x, and Lewis y) and lectins (Ulex europaeus, peanut agglutinin) having various blood-group specificities. The expression of epithelial membrane antigen was assayed with MAb MA5. The ratio of breast-cancer to normal mammary membrane preparations (C/N ratios) of these reagents was measured by densitometric scanning.

Responses of serum from breast cancer patients to murine mammary tumor virus: fact or artifact?

For determination of whether breast cancer patients possessed specific serological responses to murine mammary tumor virus (MuMTV), IgG-binding levels were monitored by antibody binding to electrophoretically separated viral proteins (Western blotting and immunodetection) and by the enzyme-linked immunosorbent assay (ELISA) against a panel of five structural proteins (gp55, gp34, p28, p18, and p12) purified from milk-borne MuMTV of the RIII isogeneic mouse strain. No significant antibody reactions were found for sera from 30 cancer patients by the immunoblotting assay, and comparative ELISA studies of 111 patients with malignant mastopathies and 122 healthy, age-matched women revealed no significantly increased mean antibody responses against gp55, gp34, p28, or p12 in breast cancer patients as compared to the responses in the control group. Only for p18 was there a significant increase in mean IgG-binding levels in cancer patients.

Isolation of two human tumor epithelial cell lines from solid breast carcinomas.

Most of the available human breast tumor cell lines have been derived from pleural effusions. The two cell lines herein described, BT-474 and BT-483, were derived from solid, invasive ductal breast carcinomas. Both are epithelial and neoplastic as judged by their general morphology, their fine structure, and their ability to produce growing nodules in nude mice and colonies in soft agar and methocel.