Understanding students' perceptions of a high school course designed to enhance school connectedness.

Background: This study was a part of an evaluation of a 4-year high school course to enhance students' school connectedness from freshman to senior year with primarily an Asian and Pacific Islander student body in Hawai'i. The purpose of this study was to understand how the course may impact students' sense of school connectedness and identify factors important in course effectiveness.

Methods: Focus group guides were developed in collaboration with course instructors.

Phenotypic impact of regulatory noise in cellular stress-response pathways.

Recent studies indicate that intrinsic promoter-mediated gene expression noise can confer a selective advantage under acute environmental stress by providing beneficial phenotypic diversity within cell populations. To investigate how extrinsic gene expression noise impacts the fitness of cell populations under stress, we engineered two nearly isogenic budding yeast strains; one carrying a two-step regulatory cascade that allows for precise control of the noise transmitted from a transcriptional regulator to a downstream stress-inducing gene, and one carrying a network with low constant upstream noise. The fitness and gene expression of these strains were compared under acute and prolonged stress exposure.

A chance at survival: gene expression noise and phenotypic diversification strategies.

Phenotypic diversification plays a central role in evolution and provides species with a capacity to survive environmental adversity. The profound impact of random molecular events on the shaping of life is well accepted in the context of chance mutations and genetic drift; however, the evolution of the regulatory networks encoding microorganismal stress response and survival strategies might also have been significantly influenced by gene expression noise. This likelihood has inspired numerous investigations to characterize the sources of phenotypic diversity within isogenic populations, and to explore their direct and potential biological implications.

Characterization of Isolates of Phytophthora infestans from Tomato and Potato in North Carolina from 1993 to 1995.

Eighty-five isolates of Phytophthora infestans from 33 tomato and 8 potato fields in North Carolina, South Carolina, and Tennessee were collected from 1993 to 1995 and tested for mating type, sensitivity to metalaxyl, and allozyme genotype at glucose-6-phosphate isomerase (Gpi) and peptidase (Pep) loci. One isolate collected from potato in eastern North Carolina in 1994 was the A1 mating type, whereas all other isolates from potato and tomato were the A2 mating type. Six isolates were sensitive to metalaxyl (<40% growth at 1.