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Full-Text Articles in Life Sciences

Salicylic Acid Attenuates Virulence In Endovascular Infections By Targeting Global Regulatory Pathways In Staphylococcus Aureus, Leon Iri Kupferwasser, Michael R. Yeaman, Cynthia C. Nast, Deborah Kupferwasser, Yan-Qiong Xiong, Marco Palma, Ambrose L. Cheung, Arnold S. Bayer Jul 2003

Salicylic Acid Attenuates Virulence In Endovascular Infections By Targeting Global Regulatory Pathways In Staphylococcus Aureus, Leon Iri Kupferwasser, Michael R. Yeaman, Cynthia C. Nast, Deborah Kupferwasser, Yan-Qiong Xiong, Marco Palma, Ambrose L. Cheung, Arnold S. Bayer

Dartmouth Scholarship

Aspirin has been previously shown to reduce the in vivo virulence of Staphylococcus aureus in experimental endocarditis, through antiplatelet and antimicrobial mechanisms. In the present study, salicylic acid, the major in vivo metabolite of aspirin, mitigated two important virulence phenotypes in both clinical and laboratory S. aureus strains: α-hemolysin secretion and fibronectin binding in vitro. In addition, salicylic acid reduced the expression of the α-hemolysin gene promoter, hla, and the fibronectin gene promoter, fnbA. Transcriptional analysis, fluorometry, and flow cytometry revealed evidence of salicylic acid–mediated activation of the stress-response gene sigB. Expression of the sigB-repressible global …


Enhancer Trapping Reveals Widespread Circadian Clock Transcriptional Control In Arabidopsis, Todd P. Michael, C Robertson Mcclung Jun 2003

Enhancer Trapping Reveals Widespread Circadian Clock Transcriptional Control In Arabidopsis, Todd P. Michael, C Robertson Mcclung

Dartmouth Scholarship

The circadian clock synchronizes the internal biology of an organism with the environment and has been shown to be widespread among organisms. Microarray experiments have shown that the circadian clock regulates mRNA abundance of about 10% of the transcriptome in plants, invertebrates, and mammals. In contrast, the circadian clock regulates the transcription of the virtually all cyanobacterial genes. To determine the extent to which the circadian clock controls transcription in Arabidopsis, we used in vivo enhancer trapping. We found that 36% of our enhancer trap lines display circadian-regulated transcription, which is much higher than estimates of circadian regulation based on …


Rpb4p, A Subunit Of Rna Polymerase Ii, Mediates Mrna Export During Stress, Marganit Farago, Tal Nahari, Christopher Hammel, Charles N. Cole, Mordechai Choder Feb 2003

Rpb4p, A Subunit Of Rna Polymerase Ii, Mediates Mrna Export During Stress, Marganit Farago, Tal Nahari, Christopher Hammel, Charles N. Cole, Mordechai Choder

Dartmouth Scholarship

Changes in gene expression represent a major mechanism by which cells respond to stress. We and other investigators have previously shown that the yeast RNA polymerase II subunit Rpb4p is required for transcription under various stress conditions, but not under optimal growth conditions. Here we show that, in addition to its role in transcription, Rpb4p is also required for mRNA export, but only when cells are exposed to stress conditions. The roles of Rpb4p in transcription and in mRNA export can be uncoupled genetically by specific mutations in Rpb4p. Both functions of Rpb4p are required to maintain cell viability during …