Unknown,Transcriptomics,Genomics,Proteomics

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Transcription profiling of S. cerevisiae cultures grown under low shear-modeled microgravity

ABSTRACT: The goal of this study was to assess whether low shear-modeled microgravity (LSMMG) effects yeast ,genomic expression patterns using the powerful tool of whole genome microarray hybridization. We determined ,changes in the yeast model organism, Saccharomyces cerevisisae, when grown in LSMMG using the rotating High ,Aspect Ratio Vessel (HARV). A significant number of genes were up- or down-regulated by at least two fold in cells ,that were grown for 5 generations or 25 generations in HARVs. We identified genes in cell wall integrity signaling ,pathways containing MAP kinase cascades that may provide clues to novel physiological responses of eukaryotic ,cells to the external stress of a low-shear modeled microgravity environment. A comparison of the microgravity ,response to other environmental stress response (ESR) genes showed that 26% of the genes that respond ,significantly to LSMMG are involved in a general environmental stress response, while 74% of the genes may ,represent a unique transcriptional response to microgravity. In addition, we found changes in genes involved in ,budding, cell polarity establishment, and cell separation that confirm our hypothesis that exposure to LSMMG ,causes changes in gene transcription resulting in a phenotypic response. The results of the study provide interesting ,clues to potential mechanisms involved in the response to, adaptation to, and survival of eukaryotic cells in a ,microgravity environment and our findings may have important health implications for human spaceflight. Experiment Overall Design: Four conditions are compared with three replicates each: yeast grown in low-shear modeled microgravity (HARV bioreactor) for 5 and 25 generations; yeast grown in a horizontal (non-LSMMG) HARV bioreactor for 5 and 25 generations.

ORGANISM(S): Saccharomyces cerevisiae

SUBMITTER: Kate McInnerney

PROVIDER: E-GEOD-4136 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Yeast genomic expression patterns in response to low-shear modeled microgravity.

Sheehan Kathy B KB McInnerney Kate K Purevdorj-Gage Boloroo B Altenburg Sara D SD Hyman Linda E LE

BMC genomics 20070103

<h4>Unlabelled</h4>The low-shear microgravity environment, modeled by rotating suspension culture bioreactors called high aspect ratio vessels (HARVs), allows investigation in ground-based studies of the effects of microgravity on eukaryotic cells and provides insights into the impact of space flight on cellular physiology. We have previously demonstrated that low-shear modeled microgravity (LSMMG) causes significant phenotypic changes of a select group of Saccharomyces cerevisiae genes associat ...[more]

PMID: 17201921

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Project description:Characterization of bacterial behavior in the microgravity environment of spaceflight is of importance towards risk assessment and prevention of infectious disease during long-term missions. Further, this research field unveils new insights into connections between low fluid-shear regions encountered by pathogens during their natural infection process in vivo, and bacterial virulence. This study is the first to characterize the global transcriptomic and proteomic response of an opportunistic pathogen that is actually found in the space habitat, Pseudomonas aeruginosa. Overall, P. aeruginosa responded to spaceflight conditions through differential regulation of 167 genes and 28 proteins, with Hfq identified as a global transcriptional regulator in the response to this environment. Since Hfq was also induced in spaceflight-grown Salmonella typhimurium, Hfq represents the first spaceflight-induced regulator across the bacterial species border. The major P. aeruginosa virulence-related genes induced in spaceflight conditions were the lecA and lecB lectins and the rhamnosyltransferase (rhlA), involved in the production of rhamnolipids. The transcriptional response of spaceflight-grown P. aeruginosa was compared with our previous data of this organism grown in microgravity-analogue conditions using the rotating wall vessel (RWV) bioreactor technology. Interesting similarities were observed, among others with regard to Hfq regulation and oxygen utilization. While LSMMG-grown P. aeruginosa mainly induced genes involved in microaerophilic metabolism, P. aeruginosa cultured in spaceflight adopted an anaerobic mode of growth, in which denitrification was presumably most prominent. Differences in hardware between spaceflight and LSMMG experiments, in combination with more pronounced low fluid shear and mixing in spaceflight when compared to LSMMG conditions, were hypothesized to be at the origin of these observations. Collectively, our data suggest that spaceflight conditions could induce the transition of P. aeruginosa from an opportunistic organism to potential pathogen, results that are of importance for infectious disease risk assessment and prevention, both during spaceflight missions and in the clinic. This study describes the transcriptional response of P. aeruginosa PAO1 to low-Earth orbit environmental conditions. Our aim was to assess whether the microgravity environment of spaceflight could induce virulence traits in P. aeruginosa. To this end, P. aeruginosa cultures were grown in space, and the expression profile was compared with ground control samples (both in biological triplicate). Two RWV samples also examined (did not re-analyze them, only compared the outputs).

Project description:Purpose: To identify orthologous genes in Xenopus that are implicated in deafness and vestibular disorders in humans and to compare RNA-Seq and microarray to determine the advantages of each technology for Xenopus transcriptomic analysis. Methods: Inner ear RNA from X. laevis stages 56-58 was isolated with the QiagenÂ® RNeasyÂ® Mini Kit. RNA quality was assessed using the Agilent 2100 Bioanalyzer. The RNA was sent to the National Center for Genome Resources, for Illumina-Solexa sequencing using the genome analyzer II and to MIT for microarray processing usign the Affymetrix GeneChipÂ® X. laevis Genome 2.0 Array. The OMIM database was mined for identification of genes causing deafness and vestibular disorder in humans. Human sequences for each of the deafness and vestibular disorders genes were downloaded from Ensembl. Blast-2.2.27+ was used to mapped the human sequences against X. tropicalis predicted proteins from JGI or to Xenopus consensus sequences downloaded from Affymetrix. The alignment of the human sequences to the predicted proteins resulted in the identification of the protein designation number. The protein designation number was used to obtain the sacaffold number and coordinates from JGI genome browser. The scaffold number and coordinates were input into Alpheus sequence variant detection pipeline to obtain the number of reads associated with each gene. The reads were log2 transformed for comparison to the microarray. In the case of the alignment of the human sequences to the Xenopus consensus sequences resulted in the PSID. The PSID was used to obtain the GCRMA intensity value. The GCRMA value and the number of reads were compared to determine which technology detected more genes. Results: Using Affymetrix GeneChipÂ® X. laevis Genome 2.0 Arrays and Illumina-Solexa sequencing methods, we determined that the transcriptional profile of the Xenopus inner ear comprises hundreds of genes that are orthologous to OMIMÂ® genes implicated in deafness and vestibular disorders in humans. Analysis of genes that mapped to both technologies showed that RNA-Seq detected more of both deafness and vestibular disorder than the Microarray. RNA-Seq and microarray detected 108 genes but RNA-Seq detected 48 genes that were below threshold criteria for microarray. While the microarray detected 11 genes that were below the expression criteria for RNA-Seq and 23 genes were below the threshold criteria for both technologies. Further analysis of the 108 genes detected by both technologies showed a minor correlation between the two technologies. Conclusions: As part of this study we identified candidate scaffold regions of the Xenopus tropicalis genome that can be used for gene mutagenesis. Furthermore, results from this study showed that the two technologies can complement each other and that a combination of both approaches can provide a more complete analysis of gene expression than either method alone. Inner ear RNA from X. laevis larval stages 56-58 was isolated and shipped to the National Center for Genome Resources, for Illumina-Solexa sequencing or to the Massachusetts Institute of Technology BioMicro Center for microarray analysis with the Affymetrix GeneChipÂ® X. laevis Genome 2.0 Array. RNA-Sequencing was completed using the Illumina-Solexa platform for sequencing by synthesis. Short-insert paired end (SIPE) libraries were prepared from total RNA according to Illuminaâ??s mRNA-Seq Sample Prep Protocol v2.0 (Illumina, San Diego, CA, USA). The resultant double-stranded cDNA concentration was measured on a NanoDrop spectrophotometer, and size and purity were determined on the 2100 Bioanalyzer using a DNA 1000 Nano kit. The cDNA libraries were cluster amplified on Illumina flowcells, sequenced on the GAII Sequencer as 36-cycle single-end reads, and processed using Illumina software v1.0. Illumina reads were aligned to the X. tropicalis genome using the algorithm for genomic mapping and alignment program (GMAP) and AlpheusÂ® Sequence Variant Detection System v3.1.

Dataset Information

Transcription profiling of S. cerevisiae cultures grown under low shear-modeled microgravity

Publications

Yeast genomic expression patterns in response to low-shear modeled microgravity.

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