Project description:Small RNA and regulatory RNA discovery has been based on (i) computational predictions mainly in intergenic regions, (ii) microarray experiments, (iii) shotgun cloning of cDNA libraries, (iv) classical cloning of abundant small RNAs after size fractionation in polyacrylamide gels and (v) copurification with proteins like Hfq, CsrA and RNA polymerase. In this study, we attempted to experimentally validate in silico small and regulatory RNA predictions for V. campbellii BAA-1116 using a microarray expression profiling strategy. Specifically, we investigated transcripts from mid-log phase cultures grown in nutrient rich media and examined their hybridization to tiled probes targeting annotated V. campbellii BAA-1116 intergenic regions. Keywords: small RNA discovery Five replicates of wild type V. campbellii BAA-1116 were grown to Mid-log phase, and total RNA was extracted from 1.0E+9 cells. Messenger RNA was isolated from the total RNA extracts treated with DNase, labeled with biotin, fragmented and hybridized to V. campbellii BAA-1116 whole genome microarray (520694F, Affymetrix).
Project description:The selective advantage of bioluminescence in bacterial cells that do not form symbiotic relationships with aquatic animals is still not known. Some evidence suggests that bioluminescence plays a role in DNA repair by a photoreactivation process (Czyz 2000) and that non-bioluminescent strains are less virulent than their bioluminescent isogenic counterparts (Ruwandeepika 2010). All hypotheses to date suggest bioluminescence associated or mediated changes in gene expression, yet the evidence for this does not exist. In this study, we generated an in-frame luxAB deletion mutant (the two contiguous genes that encode for bacterial luciferase) and compared its mid-log phase gene expression profile with that of the wild type spontaneous streptomycin resistant (STR) V. campbellii BAA-1116 parental strain from which it was derived. Both mid-log phase transcriptomes were elucidated using custom designed whole genome microarrays (520694F, Affymetrix) to determine the effect luciferase has on V. campbellii gene expression. The virulence phenotypes of both strains were also subsequently tested in Artemia franciscana challenge experiments. Three biological replicates of the wild type (STR) and luxAB deletion mutant of V. campbellii BAA-1116 were grown to mid-log phase (15 h, 200 rpm, 30M-BM-0C, in 25 mL autoinducer bioassay medium) and total RNA was extracted from 1.0E+9 cells. Messenger RNA was isolated from the total RNA extracts treated with DNase, labeled with biotin, fragmented and hybridized to V. campbellii BAA-1116 whole genome microarrays (520694F, Affymetrix).
Project description:Small RNA and regulatory RNA discovery has been based on (i) computational predictions mainly in intergenic regions, (ii) microarray experiments, (iii) shotgun cloning of cDNA libraries, (iv) classical cloning of abundant small RNAs after size fractionation in polyacrylamide gels and (v) copurification with proteins like Hfq, CsrA and RNA polymerase. In this study, we attempted to experimentally validate in silico small and regulatory RNA predictions for V. campbellii BAA-1116 using a microarray expression profiling strategy. Specifically, we investigated transcripts from mid-log phase cultures grown in nutrient rich media and examined their hybridization to tiled probes targeting annotated V. campbellii BAA-1116 intergenic regions. Keywords: small RNA discovery
Project description:Although many members of the genus Vibrio are known to inhabit the marine photic zone, an understanding of the influence of light on the molecular physiology of Vibrio spp. has largely been neglected. To begin to characterize the photophysiology of one such Vibrio sp. (Vibrio campbellii ATCC strain BAA-1116) we used microarray-based expression profiling to compare the transcriptomes of illuminated versus dark cell cultures. Specficially, we compared the transcriptomes of wild type V. campbellii (STR) cells that were cultured in M9 minimal salts medium plus glucose under two conditions: (i) after 24 hours of continuous dark and (ii) after a 12 hour dark:12 hour light cycle (white light illumination at 54 M-BM-5mol photons s-1 m-2). The results revealed a large photostimulon (differential expression of ~20% of the V. campbellii genome; adjusted p value < 0.0001) that surprisingly included ~75% of the type III secretion system (T3SS) genes which were found to be 1.6 M-bM-^@M-^S 5.4X more abundant in illuminated cultures. These findings, which were confirmed by quantitative reverse transcription PCR and quantitative membrane proteomics, strongly suggest that the photostimulon of strain BAA-1116 includes the T3SS. Five biological replicates of V. campbellii BAA-1116 (STR) were grown to log phase (200 rpm, 30M-BM-0C, 25 mL M9 minimal salts medium plus glucose in 125 mL baffled Erlenmeyer flasks) under continuous dark for 24 hours or under a 12 hour dark:12 hour light cycle (white light illumination at 54 M-BM-5mol photons s-1 m-2) and total RNA was extracted from 1.0E+9 cells. Messenger RNA was isolated from the total RNA extracts treated with DNase, labeled with biotin, fragmented and hybridized to V. campbellii BAA-1116 whole genome microarrays (520694F, Affymetrix).
Project description:The selective advantage of bioluminescence in bacterial cells that do not form symbiotic relationships with aquatic animals is still not known. Some evidence suggests that bioluminescence plays a role in DNA repair by a photoreactivation process (Czyz 2000) and that non-bioluminescent strains are less virulent than their bioluminescent isogenic counterparts (Ruwandeepika 2010). All hypotheses to date suggest bioluminescence associated or mediated changes in gene expression, yet the evidence for this does not exist. In this study, we generated an in-frame luxAB deletion mutant (the two contiguous genes that encode for bacterial luciferase) and compared its mid-log phase gene expression profile with that of the wild type spontaneous streptomycin resistant (STR) V. campbellii BAA-1116 parental strain from which it was derived. Both mid-log phase transcriptomes were elucidated using custom designed whole genome microarrays (520694F, Affymetrix) to determine the effect luciferase has on V. campbellii gene expression. The virulence phenotypes of both strains were also subsequently tested in Artemia franciscana challenge experiments.