The PAF complex and Prf1/Rtf1 delineate distinct Cdk9-dependent pathways regulating transcription elongation in fission yeast.

Cyclin-dependent kinase 9 (Cdk9) promotes elongation by RNA polymerase II (RNAPII), mRNA processing, and co-transcriptional histone modification. Cdk9 phosphorylates multiple targets, including the conserved RNAPII elongation factor Spt5 and RNAPII itself, but how these different modifications mediate Cdk9 functions is not known. Here we describe two Cdk9-dependent pathways in the fission yeast Schizosaccharomyces pombe that involve distinct targets and elicit distinct biological outcomes.

A positive feedback loop links opposing functions of P-TEFb/Cdk9 and histone H2B ubiquitylation to regulate transcript elongation in fission yeast.

Transcript elongation by RNA polymerase II (RNAPII) is accompanied by conserved patterns of histone modification. Whereas histone modifications have established roles in transcription initiation, their functions during elongation are not understood. Mono-ubiquitylation of histone H2B (H2Bub1) plays a key role in coordinating co-transcriptional histone modification by promoting site-specific methylation of histone H3.

Histone H2B ubiquitylation promotes activity of the intact Set1 histone methyltransferase complex in fission yeast.

The methylation of histone H3 at lysine 4 (H3K4me) is critical for the formation of transcriptionally active chromatin in eukaryotes. In yeast, Drosophila, and some human cell lines, H3K4me is globally stimulated by the monoubiquitylation of histone H2B (H2Bub1), another histone modification associated with transcription. The mechanism of this "trans-histone" modification pathway remains uncertain, and studies carried out in different experimental systems have suggested that H2Bub1 could either influence the subunit composition of methyltransferase complexes or directly stimulate methyltransferase activity.

The Glass Menagerie: diatoms for novel applications in nanotechnology.

Diatoms are unicellular, eukaryotic, photosynthetic algae that are found in aquatic environments. Diatoms have enormous ecological importance on this planet and display a diversity of patterns and structures at the nano- to millimetre scale. Diatom nanotechnology, a new interdisciplinary area, has spawned collaborations in biology, biochemistry, biotechnology, physics, chemistry, material science and engineering.

Adult identity mentoring: reducing sexual risk for African-American seventh grade students.

Purpose: This study was undertaken to determine whether the Adult Identity Mentoring (AIM) project successfully promotes abstinence, delays initiation of sex, and decreases intention to engage in sex.

Methods: Twenty middle school classes of African-American seventh graders were randomly assigned to receive either the AIM intervention or a standard health education control curriculum. The AIM is a 10-session curriculum based on the theory of possible selves.

Scales measuring psychosocial antecedents of coital initiation among adolescents in a rural southern state.

The psychometric properties of psychosexual scales designed to examine intentions toward sexual intercourse were examined. Participants from 22 schools in central Alabama provided data on demographics, knowledge, attitudes, beliefs, and intentions toward sexual intercourse. Theoretical constructs from Theory of Reasoned Action and Social Cognitive Theory guided the development of items assessing psychosocial aspects of sexual intercourse.

Coital status and perceptions about sexual abstinence refusal skills.

Purpose: To compare perceptions and use of sexual refusal skills.

Methods: A voluntary, anonymous sample of ninth and tenth grade students (N = 2256) reported their perceptions about and use of sexual refusal skills that had been taught in school. Forty-four percent of the students classified themselves as virgins, 18% reported one sexual partner, and 38% reported multiple sex partners.

Clustered Outbreak of Adverse Reactions to a Salsa Containing High Levels of Sulfites.

Six patients came to our attention in the Sacramento, CA area who developed cough or asthma after the ingestion of one brand (Brand 1) of refrigerated Mexican-style salsa, labelled "fresh". These patients had consumed other brands previously, not necessarily sulfited, but noted cough or asthma only in relation to consumption of this brand. Patients 1 and 2 developed reproducible severe cough and throat tightness after ingestion.