Abstract The purpose of this study was to evaluate the system capabilities of a new single-molecule detection platform capable of both genomic and proteomic analysis of cellular pathways using very small amounts of tumor material. The system has 4-color optics, single-fluorophore detection capability, localization of molecules to within a 20nm area, a flow cell with an area of 940 mm2 and the ability to detect > 109 molecules on the surface. NSCLC cell lines were cultured and untreated or treated with the EGFR tyrosine kinase inhibitor erlotinib. Cells were harvested and used to generate protein lysates, isolate mRNA and gDNA. Cellular molecules were covalently attached to an epoxysilane-coated surface on the flow cell and then repeatedly probed 10-15 times with labeled antibodies and oligonucleotides to detect, count and quantitate proteins, protein phosphorylation levels, mRNAs, fusion transcripts, and DNA mutations. We detected protein phosphorylation changes for EGFR, ERK, MET and MEK comparable to that observed by traditional western blots; however, the system required only 0.5 to 2 cell equivalents of protein lysate, containing sub pico-Molar levels of protein. We demonstrated robust and statistically significant detection of 2-fold changes in protein levels across 3 slides, in triplicate lanes and performed over 3 non-consecutive days by 3 operators (Tukey-Kramer tests). We also detected 8 mRNAs, with no PCR amplification required, in a multiplexed format with relative levels similar to that observed with TaqMan® qPCR tests. We demonstrated protein detection at ~ 100% recovery compared to an ELISA test and nucleic acid recovery at ~ 30% with no amplification. We also detected exon 19 deletions in EGFR, point mutations at L858R, T790M in EGFR and V600E in BRAF, at 0.5% minor allele levels, by using an oligonucleotide ligation assay off-chip and then attaching the ligated product to the surface. mRNA levels were detected using 10-20 cell equivalents of RNA. We believe the system will enable comprehensive analysis of cancer-related pathways, requiring only a few cells, to help decipher cellular pathway activity induced by driver mutations and consequently help with selection of efficacious drugs tailored for specific individuals based on comprehensive molecular analysis. Citation Format: Manohar R. Furtado, Rixun Fang, Norman Burns, Rebekah Burich, Catherine Le, Soumya Ivaturi, Rob Hartlage, Ed Zizminskas, Jim Jahncke, Philip C. Mack, Bryan P. Staker. A single molecule detection system for comprehensive analysis of cancer related cellular pathways [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 415.
Many panels of ancestry informative single nucleotide polymorphisms have been proposed in recent years for various purposes including detecting stratification in biomedical studies and determining an individual's ancestry in a forensic context. All of the panels have limitations in their generality and efficiency for routine forensic work. Some panels have used only a few populations to validate them. Some panels are based on very large numbers of SNPs thereby limiting the ability of others to test different populations. We have been working toward an efficient and globally useful panel of ancestry informative markers that is comprised of a small number of highly informative SNPs. We have developed a panel of 55 SNPs analyzed on 73 populations from around the world. We present the details of the panel and discuss its strengths and limitations.
Background: Within the last decade, Salmonella enterica subsp. enterica serovar Cerro (S. Cerro) has become one of the most common serovars isolated from cattle and dairy farm environments in the northeastern US. The fact that this serovar is commonly isolated from subclinically infected cattle and is rarely associated with human disease, despite its frequent isolation from cattle, has led to the hypothesis that this emerging serovar may be characterized by reduced virulence. We applied comparative and population genomic approaches to (i) characterize the evolution of this recently emerged serovar and to (ii) gain a better understanding of genomic features that could explain some of the unique epidemiological features associated with this serovar.Results: In addition to generating a de novo draft genome for one Salmonella Cerro strain, we also generated whole genome sequence data for 26 additional S. Cerro isolates, including 16 from cattle operations in New York (NY) state, 2 from human clinical cases from NY in 2008, and 8 from diverse animal sources (7 from Washington state and 1 from Florida). All isolates sequenced in this study represent sequence type ST367. Population genomic analysis showed that isolates from the NY cattle operations form a well-supported clade within S. Cerro ST367 (designated here "NY bovine clade"), distinct from isolates from Washington state, Florida and the human clinical cases. A molecular clock analysis indicates that the most recent common ancestor of the NY bovine clade dates back to 1998, supporting the recent emergence of this clone.Comparative genomic analyses revealed several relevant genomic features of S. Cerro ST367, that may be responsible for reduced virulence of S. Cerro, including an insertion creating a premature stop codon in sopA. In addition, patterns of gene deletion in S. Cerro ST367 further support adaptation of this clone to a unique ecological or host related niche.Conclusions: Our results indicate that the increase in prevalence of S. Cerro ST367 is caused by a highly clonal subpopulation and that S. Cerro ST367 is characterized by unique genomic deletions that may indicate adaptation to specific ecological niches and possibly reduced virulence in some hosts.
Toll-like receptor 1, when dimerized with Toll-like receptor 2, is a cell surface receptor that, upon recognition of bacterial lipoproteins, activates the innate immune system. Variants in TLR1 associate with the risk of a variety of medical conditions and diseases, including sepsis, leprosy, tuberculosis, and others. The foremost of these is rs5743618 c.2079T>G(p.(Ile602Ser)), the derived allele of which is associated with reduced risk of sepsis, leprosy, and other diseases. Interestingly, 602Ser, which shows signatures of selection, inhibits TLR1 surface trafficking and subsequent activation of NFκB upon recognition of a ligand. This suggests that reduced TLR1 activity may be beneficial for human health. To better understand TLR1 variation and its link to human health, we have typed all 7 high-frequency missense variants (>5% in at least one population) along with 17 other variants in and around TLR1 in 2548 individuals from 56 populations from around the globe. We have also found additional signatures of selection on missense variants not associated with rs5743618, suggesting that there may be multiple functional alleles under positive selection in this gene.
18 a Present address: Eureka Genomics, 750 Alfred Nobel Drive, Hercules, CA, 94547 19 b Present address: Wafergen Biosystems, 7400 Paseo Padre Parkway, Fremont, CA 94555 20 c Present address: Genentech Inc., 1 DNA Way, South San Francisco, CA 94080 21 d Present address: 12170 Calle Uvas, Gilroy, CA, 95020 22 e Present address: 3180 Melendy Drive, San Carlos, CA, 94070 23 Copyright © 2012, American Society for Microbiology. All Rights Reserved. J. Bacteriol. doi:10.1128/JB.00120-12 JB Accepts, published online ahead of print on 10 February 2012
The transcription factor pancreatic and duodenal homeobox 1 (PDX1) plays an essential role in pancreatic development and in maintaining proper islet function via target gene regulation. Few intestinal PDX1 targets, however, have been described. We sought to define novel PDX1-regulated intestinal genes. Caco-2 human intestinal epithelial cells were engineered to overexpress PDX1 and gene expression profiles relative to control cells were assessed. Expression of 80 genes significantly increased while that of 49 genes significantly decreased more than 4-fold following PDX1 overexpression in differentiated Caco-2 cells. Analysis of the differentially regulated genes with known functional annotations revealed genes encoding transcription factors, growth factors, kinases, digestive glycosidases, nutrient transporters, nutrient binding proteins, and structural components. The gene for fatty acid binding protein 1, liver, FABP1, is repressed by PDX1 in Caco-2 cells. PDX1 overexpression in Caco-2 cells also results in repression of promoter activity driven by the 0.6 kb FABP1 promoter. PDX1 regulation of promoter activity is consistent with the decrease in FABP1 RNA abundance resulting from PDX1 overexpression and identifies FABP1 as a candidate PDX1 target. PDX1 repression of FABP1, LCT, and SI suggests a role for PDX1 in patterning anterior intestinal development.
La presente invention concerne des compositions, des procedes et des necessaires permettant la detection d'un ou de multiples microorganismes contaminant des echantillons. Certains modes de realisation concernent la detection d'un ou plusieurs microorganismes produisant des agressines comme une shiga-toxine ( stx ) ou une eae . Dans certains modes de realisation, des compositions, des procedes et des necessaires permettent de detecter et d'identifier diverses souches et divers serotypes de microorganismes produisant des shiga-toxines. Certains modes de realisation concernent des compositions, des procedes et des necessaires permettant la detection de bacteries de type STEC. L'invention concerne egalement le deroulement des operations de detection et d'identification de multiples microbes.
18 a Present address: Eureka Genomics, 750 Alfred Nobel Drive, Hercules, CA, 94547 19 b Present address: Wafergen Biosystems, 7400 Paseo Padre Parkway, Fremont, CA 94555 20 c Present address: Genentech Inc., 1 DNA Way, South San Francisco, CA 94080 21 d Present address: 12170 Calle Uvas, Gilroy, CA, 95020 22 e Present address: 3180 Melendy Drive, San Carlos, CA, 94070 23 Copyright © 2012, American Society for Microbiology. All Rights Reserved. J. Bacteriol. doi:10.1128/JB.00120-12 JB Accepts, published online ahead of print on 10 February 2012
ABSTRACT Enteropathogenic Escherichia coli (EPEC) continues to be a leading cause of mortality and morbidity in children around the world. Two EPEC genomes have been fully sequenced: those of EPEC O127:H6 strain E2348/69 (United Kingdom, 1969) and EPEC O55:H7 strain CB9615 (Germany, 2003). The O55:H7 serotype is a recent precursor to the virulent enterohemorrhagic E. coli O157:H7. To explore the diversity of O55:H7 and better understand the clonal evolution of O157:H7, we fully sequenced EPEC O55:H7 strain RM12579 (California, 1974), which was collected 1 year before the first U.S. isolate of O157:H7 was identified in California. Phage-related sequences accounted for nearly all differences between the two O55:H7 strains. Additionally, O55:H7 and O157:H7 strains were tested for the presence and insertion sites of Shiga toxin gene ( stx )-containing bacteriophages. Analysis of non-phage-associated genes supported core elements of previous O157:H7 stepwise evolutionary models, whereas phage composition and insertion analyses suggested a key refinement. Specifically, the placement and presence of lambda-like bacteriophages (including those containing stx ) should not be considered stable evolutionary markers or be required in placing O55:H7 and O157:H7 strains within the stepwise evolutionary models. Additionally, we suggest that a 10.9-kb region (block 172) previously believed unique to O55:H7 strains can be used to identify early O157:H7 strains. Finally, we defined two subsets of O55:H7 strains that share an as-yet-unobserved or extinct common ancestor with O157:H7 strains. Exploration of O55:H7 diversity improved our understanding of the evolution of E. coli O157:H7 and suggested a key revision to accommodate existing and future configurations of stx -containing bacteriophages into current models.
The potential value of SNPs for individual identification has been recognized by many researchers and different panels have been proposed. Here we present a new interface in the ALFRED database to access compendia of allele frequencies for several published panels of markers for forensic uses. One of those is our panel of individual identification SNPs (IISNPs) based on samples of 44 populations originating from many parts of the world. Here we also present additional data and additional statistical analyses that continue to support the value of our panel of IISNPs as a universal panel. We also describe initial developments of multiplex methods and various robustness analyses for our 45 marker IISNP panel.
We propose that haplotyped loci with high heterozygosity can be useful in human identification, especially within families, if recombination is very low among the sites. Three or more SNPs extending over small molecular intervals (<10 KB) can be identified in the human genome to define miniature haplotypes with moderate levels of linkage disequilibrium. Properly selected, these mini-haplotypes (or minihaps) consist of multiple haplotype lineages (alleles) that have evolved from the ancestral human haplotype but show no evidence of recurring recombination, allowing each distinct haplotype to be equated with an allele, all copies of which are essentially identical by descent. Historic recombinants, representing rare events that have drifted to common frequencies over many generations, can be identified in some cases, they do not equate to frequently recurring recombination. We have identified examples in our data collected on various projects and present eight such mini-haplotypes comprised of informative SNPs. We also discuss the ideal characteristics and advantages of minihaps for human familial identification and ancestry inference, and compare them to other types of forensic markers in use and/or that have been proposed. We expect that it is possible to carry out a systematic search and identify a useful panel of mini-haplotypes, with even better properties than the examples presented here.
Abstract Rapid and accurate identification of SNPs and mutations are useful in ensuring that the correctly identified cell lines are being used in cancer research studies and for accurate identification of SNPs and indels in cancer cells. In this study we report on a method that uses nucleic acid isolation methods, multiplexed PCR to amplify up to 48 regions within the human genome followed by an oligonucleotide ligation assay that can detect SNPs, mutations and indels. The protocol takes about 4 hrs to complete and uses panels optimized for human cell identification and detection of mutations in EGFR and KRAS genes. We typed the NCI-60 panel and several cell lines from the ATCC using two panels. One is a panel of SNPs that has been tested with samples from over 46 human populations to identify a set of SNPs that would discriminate globally. This SNP set has 48 markers with high heterozygosity (>0.4) and low Fst values (<0.06) across multiple human populations. The panel has a high power of discrimination. (Hum Genet; 127 (3) 315-324; 2010) comparable to that obtained with STR kits. A panel of 31 samples from closely related individuals within families was typed to test the power of discrimination. In another study, we applied this system to a cancer mutation study, in which an assay for detecting 29 EGFR and 5 KRAS gene mutations was developed. These mutations are frequently found in human cancers. DNA preparations from 48 ATCC and 60 NCI tumor cell lines were genotyped by this assay. These SNPs and mutations were further confirmed by the Sanger sequencing chemistry, showing 100% concordance between two technologies. The information generated from this study will be definitely useful when these cell lines are used as models for cancer study and cancer drug screening. In conclusion, we have developed a sensitive, highly accurate, high throughput genotyping system. Studies have demonstrated its effectiveness for successful SNP/InDel detection and mutation screening. This system has been successfully used for oncogen mutation studies in cancer cell lines. Overall, the system can become a valuable tool for molecular and clinical diagnostics. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3883. doi:10.1158/1538-7445.AM2011-3883
ABSTRACT In this study, we report a whole-genome single nucleotide polymorphism (SNP)-based evolutionary approach to study the epidemiology of a multistate outbreak of Salmonella enterica subsp. enterica serovar Montevideo. This outbreak included 272 cases that occurred in 44 states between July 2009 and April 2010. A case-control study linked the consumption of salami made with contaminated black and red pepper to the outbreak. We sequenced, on the SOLiD System, 47 isolates with XbaI PFGE pattern JIXX01.0011, a common pulsed-field gel electrophoresis (PFGE) pattern associated with isolates from the outbreak. These isolates represented 20 isolates collected from human sources during the period of the outbreak and 27 control isolates collected from human, food, animal, and environmental sources before the outbreak. Based on 253 high-confidence SNPs, we were able to reconstruct a tip-dated molecular clock phylogeny of the isolates and to assign four human isolates to the actual outbreak. We developed an SNP typing assay to rapidly discriminate between outbreak-related cases and non-outbreak-related cases and tested this assay on an extended panel of 112 isolates. These results suggest that only a very small percentage of the human isolates with the outbreak PFGE pattern and obtained during the outbreak period could be attributed to the actual pepper-related outbreak (20%), while the majority (80%) of the putative cases represented background cases. This study demonstrates that next-generation-based SNP typing provides the resolution and accuracy needed for outbreak investigations of food-borne pathogens that cannot be distinguished by currently used subtyping methods.
Forensic analysts routinely encounter samples containing mixtures of DNA from male and female contributors and PCR inhibitors due to exposure to environmental insults.In order to select the appropriate STR analysis methodology for such samples and obtain optimal results at first pass, it is desirable to determine the relative quantities of male and female DNA and to detect the presence of PCR inhibitors at an early stage in the sample processing workflow.Here we describe a multiplex real-time PCR assay that can provide the desired information in a single reaction.Briefly, the simultaneous quantification of human and human male DNA is achieved by measuring the RPPH1 human target and the SRY male-specific target.At the same time a synthetic sequence is co-amplified as an Internal PCR Control (IPC) to detect the presence of PCR inhibitors.The assay has a good dynamic range (0.023-50 ng/µL) and can detect 25 pg/µL of human male DNA in the presence of ten thousand-fold excess of human female DNA.In addition, the ability of the assay to predict PCR inhibition was demonstrated by shifted IPC C T values in the presence of increasing quantities of hematin.All the real-time PCR results showed a good correlation with the downstream STR profiles obtained from a large set of various sample types therefore demonstrating that this assay can be considered a guiding tool to predict the performance of the STR genotyping kits with forensic samples.
Autosomal DNA polymorphisms can provide new information and understanding of both the origins of and relationships among modern Native American populations. At the same time that autosomal markers can be highly informative, they are also susceptible to ascertainment biases in the selection of the markers to use. Identifying markers that can be used for ancestry inference among Native American populations can be considered separate from identifying markers to further the quest for history. In the current study, we are using data on nine Native American populations to compare the results based on a large haplotype-based dataset with relatively small independent sets of single nucleotide polymorphisms. We are interested in what types of limited datasets an individual laboratory might be able to collect are best for addressing two different questions of interest. First, how well can we differentiate the Native American populations and/or infer ancestry by assigning an individual to her population(s) of origin? Second, how well can we infer the historical/evolutionary relationships among Native American populations and their Eurasian origins? We conclude that only a large comprehensive dataset involving multiple autosomal markers on multiple populations will be able to answer both questions; different small sets of markers are able to answer only one or the other of these questions. Using our largest dataset, we see a general increasing distance from Old World populations from North to South in the New World except for an unexplained close relationship between our Maya and Quechua samples.
BACKGROUND:In the event of biocrimes or infectious disease outbreaks, high-resolution genetic characterization for identifying the agent and attributing it to a specific source can be crucial for an effective response. Until recently, in-depth genetic characterization required expensive and time-consuming Sanger sequencing of a few strains, followed by genotyping of a small number of marker loci in a panel of isolates at or by gel-based approaches such as pulsed field gel electrophoresis, which by necessity ignores most of the genome. Next-generation, massively parallel sequencing (MPS) technology (specifically the Applied Biosystems sequencing by oligonucleotide ligation and detection (SOLiD™) system) is a powerful investigative tool for rapid, cost-effective and parallel microbial whole-genome characterization.RESULTS:To demonstrate the utility of MPS for whole-genome typing of monomorphic pathogens, four Bacillus anthracis and four Yersinia pestis strains were sequenced in parallel. Reads were aligned to complete reference genomes, and genomic variations were identified. Resequencing of the B. anthracis Ames ancestor strain detected no false-positive single-nucleotide polymorphisms (SNPs), and mapping of reads to the Sterne strain correctly identified 98% of the 133 SNPs that are not clustered or associated with repeats. Three geographically distinct B. anthracis strains from the A branch lineage were found to have between 352 and 471 SNPs each, relative to the Ames genome, and one strain harbored a genomic amplification. Sequencing of four Y. pestis strains from the Orientalis lineage identified between 20 and 54 SNPs per strain relative to the CO92 genome, with the single Bolivian isolate having approximately twice as many SNPs as the three more closely related North American strains. Coverage plotting also revealed a common deletion in two strains and an amplification in the Bolivian strain that appear to be due to insertion element-mediated recombination events. Most private SNPs (that is, a, variant found in only one strain in this set) selected for validation by Sanger sequencing were confirmed, although rare false-positive SNPs were associated with variable nucleotide tandem repeats.CONCLUSIONS:The high-throughput, multiplexing capability, and accuracy of this system make it suitable for rapid whole-genome typing of microbial pathogens during a forensic or epidemiological investigation. By interrogating nearly every base of the genome, rare polymorphisms can be reliably discovered, thus facilitating high-resolution strain tracking and strengthening forensic attribution.
both long and short chains as well by cleaving alpha-1,6 linkages and is the only subunit with this activity.A combination of four subunits reached highest glucogenesis indicating a broader spectrum of glucosidase activities than any individual subunit alone.Some alpha-LDx was not completely available for enzyme hydrolysis, and residues are considered either slowly digestible or resistant to human enzyme digestion.This study for the first time shows the direct role of individual mucosal glucosidase subunits in starch digestion and reveals the potential of producing slow glucose release dextrins.