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Full-Text Articles in Environmental Microbiology and Microbial Ecology

The Global Response Of Nostoc Punctiforme Atcc 29133 To Uva Stress, Assessed In A Temporal Dna Microarray Study, Tanya Soule, Qunjie Gao, Valerie Stout, Ferran Garcia-Pichel Feb 2013

The Global Response Of Nostoc Punctiforme Atcc 29133 To Uva Stress, Assessed In A Temporal Dna Microarray Study, Tanya Soule, Qunjie Gao, Valerie Stout, Ferran Garcia-Pichel

Tanya Soule

Cyanobacteria in nature are exposed not only to the visible spectrum of sunlight but also to its harmful ultraviolet components (UVA and UVB). We used Nostoc punctiforme ATCC 29133 as a model to study the UVA response by analyzing global gene expression patterns using genomic microarrays. UVA exposure resulted in the statistically detectable differential expression of 573 genes of the 6903 that were probed, compared with that of the control cultures. Of those genes, 473 were up-regulated, while only 100 were down-regulated. Many of the down-regulated genes were involved in photosynthetic pigment biosynthesis, indicating a significant shift in this metabolism. …


The Acid Stress Response Of The Cyanobacterium Synechocystis Sp. Strain Pcc 6308, Jean Huang, Nancy Kolodny, Jennifer Redfearn, Mary Allen May 2012

The Acid Stress Response Of The Cyanobacterium Synechocystis Sp. Strain Pcc 6308, Jean Huang, Nancy Kolodny, Jennifer Redfearn, Mary Allen

Jean J. Huang

The cyanobacterium Synechocystis sp. strain PCC 6308 has been shown to exhibit predictable physiological responses to acid stress. Originally isolated from a Wisconsin lake, this cyanobacterium grows optimally under alkaline conditions in the laboratory. After acid stress at a pH of between 4.4 and 7.7, cells return to exponential growth following a lag phase. The organism's response to this tolerable acid stress involves cell concentration-dependent neutralization of the external medium to pH 6 or above within 5 min, maintenance of a transmembrane pH gradient, and maintenance of photosystem II efficiency. Lethal acid stress, at a pH below 4.4, results in …