Project description:Is there a universal genetically programmed defense providing tolerance to antibiotics when bacteria grow as biofilms? A comparison between biofilms of three different bacterial species by transcriptomic and metabolomic approaches uncovered no evidence of one. Single-species biofilms of three bacterial species (Pseudomonas aeruginosa, Staphylococcus aureus, and Acinetobacter baumannii) were grown in vitro for three days then challenged with respective antibiotics (ciprofloxacin, daptomycin, tigecycline) for an additional 24 h. All three microorganisms displayed reduced susceptibility in biofilms compared to planktonic cultures. Global transcriptomic profiling of gene expression comparing biofilm to planktonic and antibiotic-treated biofilm to untreated biofilm was performed. Extracellular metabolites including 18 amino acids, glucose, lactate, acetate, formate, and ethanol were measured to characterize the utilization of carbon sources between biofilms, treated biofilms, and planktonic cells. While all three bacteria exhibited a species-specific signature of stationary phase, no conserved gene, gene set, or common functional pathway could be identified that changed consistently across the three microorganisms. Across the three species, glucose consumption was increased in biofilms compared to planktonic cells and alanine and aspartic acid utilization were decreased in biofilms compared to planktonic cells. The reasons for these changes were not readily apparent in the transcriptomes. No common shift in the utilization pattern of carbon sources was discerned when comparing untreated to antibiotic-exposed biofilms. Overall, our measurements do not support the existence of a common genetic or biochemical basis for biofilm tolerance against antibiotics. Rather, there are likely myriad genes, proteins, and metabolic pathways that influence the physiological state of microorganisms in biofilms contributing to antibiotic tolerance. The Staphylococcus aureus microarray data from the study described above is deposited here.
Project description:Is there a universal genetically programmed defense providing tolerance to antibiotics when bacteria grow as biofilms? A comparison between biofilms of three different bacterial species by transcriptomic and metabolomic approaches uncovered no evidence of one. Single-species biofilms of three bacterial species (Pseudomonas aeruginosa, Staphylococcus aureus, and Acinetobacter baumannii) were grown in vitro for three days then challenged with respective antibiotics (ciprofloxacin, daptomycin, tigecycline) for an additional 24 h. All three microorganisms displayed reduced susceptibility in biofilms compared to planktonic cultures. Global transcriptomic profiling of gene expression comparing biofilm to planktonic and antibiotic-treated biofilm to untreated biofilm was performed. Extracellular metabolites including 18 amino acids, glucose, lactate, acetate, formate, and ethanol were measured to characterize the utilization of carbon sources between biofilms, treated biofilms, and planktonic cells. While all three bacteria exhibited a species-specific signature of stationary phase, no conserved gene, gene set, or common functional pathway could be identified that changed consistently across the three microorganisms. Across the three species, glucose consumption was increased in biofilms compared to planktonic cells and alanine and aspartic acid utilization were decreased in biofilms compared to planktonic cells. The reasons for these changes were not readily apparent in the transcriptomes. No common shift in the utilization pattern of carbon sources was discerned when comparing untreated to antibiotic-exposed biofilms. Overall, our measurements do not support the existence of a common genetic or biochemical basis for biofilm tolerance against antibiotics. Rather, there are likely myriad genes, proteins, and metabolic pathways that influence the physiological state of microorganisms in biofilms contributing to antibiotic tolerance. The Acinetobacter baumannii microarray data from the study described above is deposited here.
Project description:Investigation of partial genome gene expression level changes in a Desulfovibrio africanus during exponential and stationary phase growth in the presence and absence of 5 ug/L Hg2+ (as HgNO3). Desulfovibrio africanus is a known mercury methylating bacteria
Project description:The consistent cold temperatures and large amount of precipitation in the Olympic and Cascade ranges of Washington State are thought to increase atmospheric deposition of contaminants in these high elevation locations. Total mercury and 28 organochlorine compounds were measured in composite, whole fish samples collected from 14 remote lakes in the Olympic, Mt. Rainer, and North Cascades National Parks. Mercury was detected in fish from all lakes sampled and ranged in concentration from 17 to 262 ug/kg wet weight. Only two organochlorines, total polychlorinated biphenyls (tPCB) and dichlorodiphenyldichloroethylene (DDE), were detected in fish tissues (concentrations <25 ug/kg wet weight). No organochlorines were detected in sediments (MRL ≈1-5 ug/kg), while median total and methyl mercury in sediments were 30.4 and 0.34 ug/kg (dry weight), respectively. Using a targeted rainbow trout cDNA microarray with known genes, we detected significant differences in liver transcriptional responses, including metabolic, endocrine, and immune-related genes, in fish collected from a contaminated lake compared to a lake with a lower contaminant load. Overall, our results suggest that local urban areas are contributing to the observed contaminant patterns, while the transcriptional changes point to a biological response associated with exposure to these contaminants in fish. Specifically, the gene expression pattern leads us to hypothesize a role for mercury in disrupting the metabolic and reproductive pathways in fish from high elevation lakes in western Washington. Keywords: High altitude lakes, mercury, salmonids, organochlorines
Project description:We are investigating the mRNA expression profiles of human lung cells to gaseous urban mixtures We used microarrays to compare the global mRNA expression profiles upon response to fresh against aged urban mix Keywords: dose A549 cells were grown to confluency and exposed to fresh urban mix, aged urban mix, or mock-treated. RNA was collected 9 hrs after exposure.
Project description:We are investigating the mRNA expression profiles of human lung cells to gaseous urban mixtures We used microarrays to compare the global mRNA expression profiles upon response to fresh against aged urban mix Keywords: dose
Project description:Rainbow darter (Etheostoma caeruleum) are a small benthic fish found in North America. This species is sensitive to sewage effluent in the environment, showing the presence of intersex in up to 80% of males in near-field areas in the Grand River, ON. To learn more about the molecular events associated with intersex, we developed a customized oligonucleotide microarray (4x180K) with next generation sequencing (454 Roche) to characterize molecular responses in the gonad. Transcriptomics was performed on both males and females from both a reference site and a polluted site. Males with and without intersex from the polluted site were compared to the control males. Rainbow darter were sampled from from the Grand River in May 2011. Fish were selected according to the location, gonad maturity, and intersex index. Reference fish were taken from the upstream to the urban area; exposed fish were taken from downstream of from Kitchener MWWE treatment plant.
Project description:This study explores the impact of lifestyle and environment on gene expression through whole transcriptome profiling of peripheral blood samples in Fijian population (native Melanesians and Indians) living in the rural and urban areas. 41 individuals (14 urban Melanesians, 10 rural Melanesians and 17 urban Indians) of both gender were sampled under informed consents. Only healthy individuals aged between 18 and 65 were sampled. RNA from each sample was hybridized to an Illumina array. No replicates were done in this study
Project description:Investigation of partial genome gene expression level changes in a Desulfovibrio africanus during exponential and stationary phase growth in the presence and absence of 5 ug/L Hg2+ (as HgNO3). Desulfovibrio africanus is a known mercury methylating bacteria A 3 chip study using total RNA recovered from three separate cultures of Desulfovibrio africanus with 5 ug/L Hg during exponential phase growth, three seperate cultures of Desulfovibrio africanus with 5 ug/L Hg during stationary phase growth, three cultures of Desulfovibrio africanus without Hg during exponential phase growth, and Desulfovibrio africanus without Hg during stationary phase growth. Each chip measures the expression level of 4,585 genes and intergenic regions from Desulfovibrio africanus strain Walvis Bay on a custom Nimblegen format with 75-mer probes with tiled in 4-plex format.