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At least 811 records · Page 45Linked to original sources
PubMed1991

Genomic groups and biochemical profiles of clinical isolates of Enterobacter cloacae.

A collection of 123 clinical strains presumptively identified as Enterobacter cloacae and 12 type and reference strains of Enterobacter spp. were genotypically investigated by a quantitative bacterial dot method for DNA-DNA hybridization, giving an estimate of delta Tm (difference in thermal denaturation midpoint between homologous and heterologous duplexes). The API 20E system was used for phenotypic characterization. Using discontinuities in the values of delta Tm as criterion, five genomic groups of E. cloacae could be demonstrated, eleven ungrouped strains representing at least one additional group. Nine API profiles were found, the ideal phenotype of E. cloacae (i.e. the phenotype showing the most common reaction for the species in all tests studied) being the most frequently found. The type strain of E. cloacae and the reference strain CDC 1347-71 represented rather small genomic groups of three and eight strains respectively, most of them inositol positive. A majority of 98 isolates formed one single genomic group, biochemically dominated by the ideal phenotype. The genomic groups could not be differentiated phenotypically. At present there seems to be no reason for an attempt to split E. cloacae into two or more species. The type strain of E. dissolvens showed itself to be closely related to the type strain of E. cloacae (delta Tm 2.3 degrees C), indicating that the two species may be regarded as subjective synonyms.

DNA, Bacterial↗
PubMed2006

Expression profiling by whole-genome interspecies microarray hybridization reveals differential gene expression in procyclic promastigotes, lesion-derived amastigotes, and axenic amastigotes in Leishmania mexicana.

We examined the Leishmania mexicana transcriptome to identify differentially regulated mRNAs using high-density whole-genome oligonucleotide microarrays designed from the genome data of a closely related species, Leishmania major. Statistical analysis on array hybridization data representing 8156 predicted coding regions revealed 288 genes (3.5% of all genes) whose steady-state mRNA levels meet criteria for differential regulation between promastigotes and lesion-derived amastigotes. Interestingly, sample comparison of promastigotes to axenic amastigotes resulted in only 17 genes (0.2%) that meet the same statistical criteria for differential regulation. The reduced number of regulated genes is a consequence of an increase in the magnitude of the transcript levels in cells under axenic conditions. The expression data for a subset of genes was validated by quantitative PCR. Our studies show that interspecies hybridization on microarrays can be used to analyze closely related protozoan parasites, that axenic culture conditions may alter amastigote transcript abundance, and that there is only a relatively modest change in abundance of a few mRNAs between morphologically distinct promastigote and amastigote cultured cells. Leishmania may represent an alternative paradigm for eukaryotic differentiation with minimal contributions from changes in mRNA abundance.

Animals↗
PubMed2000

Genomic sequence and transcriptional profile of the boundary between pericentromeric satellites and genes on human chromosome arm 10q.

The organization of centromeric heterochromatin has been established in a number of eucaryotes but remains poorly defined in human. Here we present 1025 kb of contiguous human genomic sequence which links pericentromeric satellites to the RET proto-oncogene in 10q11.2 and is presumed to span the transition from centric heterochromatin to euchromatin on this chromosome arm. Two distinct domains can be defined within the sequence. The proximal approximately 240 kb consists of arrays of satellites and other tandem repeats separated by tracts of complex sequence which have evolved by pericentromeric-directed duplication. Analysis of 32 human paralogues of these sequences indicates that most terminate at or within repeat arrays, implicating these repeats in the interchromosomal duplication process. Corroborative PCR-based analyses establish a genome-wide correlation between the distribution of these paralogues and the distribution of satellite families present in 10q11. In contrast, the distal approximately 780 kb contains few tandem repeats and is largely chromosome specific. However, a minimum of three independent intrachromosomal duplication events have resulted in >370 kb of this sequence sharing >90% identity with sequences on 10p. Using computer-based analyses and RT-PCR we confirm the presence of three genes within the sequence, ZNF11/33B, KIAA0187 and RET, in addition to five transcripts of unknown structure. All of these transcribed sequences map distal to the satellite arrays. The boundary between satellite-rich interchromosomally duplicated DNA and chromosome-specific DNA therefore appears to define a transition from pericentromeric heterochromatin to euchromatin on the long arm of this chromosome.

Centromere↗
PubMed2004

Recent translational research: microarray expression profiling of breast cancer--beyond classification and prognostic markers?

Genomic expression profiling has greatly improved our ability to subclassify human breast cancers according to shared molecular characteristics and clinical behavior. The logical next question is whether this technology will be similarly useful for identifying the dominant signaling pathways that drive tumor initiation and progression within each breast cancer subtype. A major challenge will be to integrate data generated from the experimental manipulation of model systems with expression profiles obtained from primary tumors. We highlight some recent progress and discuss several obstacles in the use of expression profiling to identify pathway signatures in human breast cancer.

Animals↗
PubMed2004

Cloning, genomic structure, and expression profiles of TULIP1 (GARNL1), a brain-expressed candidate gene for 14q13-linked neurological phenotypes, and its murine homologue.

Previously, we have described the clinical and molecular characterization of a de novo 14q13.1-q21.1 microdeletion, less than 3.5 Mb in size, in a patient with severe microcephaly, psychomotor retardation, and other clinical anomalies. Here we report the characterization of the genomic structure of the human tuberin-like protein gene 1 (TULIP1; approved gene symbol GARNL1), a CpGisland-associated, brain-expressed candidate gene for the neurological findings in our patient, and its murine homologue. The human TULIP1 gene was mapped to chromosome band 14q13.2 by fluorescence in situ hybridization of BAC clone RP11-355C3 (GenBank Accession No. AL160231), containing the 3' region of the gene. TULIP1 spans about 271 kb of human genomic DNA and is divided into 41 exons. An untranscribed, processed pseudogene of TULIP1 was found on human chromosome band 9q31.1. The active locus TULIP1, encoding a predicted protein of 2036 amino acids, is expressed ubiquitously in pre- and postnatal human tissues. The murine homologue Tulip1 spans about 220 kb of mouse genomic DNA and is also divided into 41 exons, encoding a predicted protein of 2035 amino acids. No pseudogene could be found in the available mouse sequence data. Several splicing variants were found. Considering the location, expression profile, and predicted function, TULIP1 is a strong candidate for several neurological features seen in 14q deletion patients. Additionally we searched for mutations in the coding region of TULIP1 in subjects from a family with idiopathic basal ganglia calcification (IBGC; Fahr disease), previously linked to chromosome 14q. We identified two novel SNPs in the intron-exon boundaries; however, they did not segregate only with affected subjects in the predicted model of an autosomal dominant disease such as IBGC.

Amino Acid Sequence↗
PubMed2006

Transcript mapping with high-density oligonucleotide tiling arrays.

MOTIVATION: High-density DNA tiling microarrays are a powerful tool for the characterization of complete transcriptomes. The two major analytical challenges are the segmentation of the hybridization signal along genomic coordinates to accurately determine transcript boundaries and the adjustment of the sequence-dependent response of the oligonucleotide probes to achieve quantitative comparability of the signal between different probes. RESULTS: We describe a dynamic programming algorithm for finding a globally optimal fit of a piecewise constant expression profile along genomic coordinates. We developed a probe-specific background correction and scaling method that employs empirical probe response parameters determined from reference hybridizations with no need for paired mismatch probes. This combined analysis approach allows the accurate determination of dynamical changes in transcription architectures from hybridization data and will help to study the biological significance of complex transcriptional phenomena in eukaryotic genomes. AVAILABILITY: R package tilingArray at http://www.bioconductor.org.

Algorithms↗
PubMed2006

The plant energy-dissipating mitochondrial systems: depicting the genomic structure and the expression profiles of the gene families of uncoupling protein and alternative oxidase in monocots and dicots.

The simultaneous existence of alternative oxidases and uncoupling proteins in plants has raised the question as to why plants need two energy-dissipating systems with apparently similar physiological functions. A probably complete plant uncoupling protein gene family is described and the expression profiles of this family compared with the multigene family of alternative oxidases in Arabidopsis thaliana and sugarcane (Saccharum sp.) employed as dicot and monocot models, respectively. In total, six uncoupling protein genes, AtPUMP1-6, were recognized within the Arabidopsis genome and five (SsPUMP1-5) in a sugarcane EST database. The recombinant AtPUMP5 protein displayed similar biochemical properties as AtPUMP1. Sugarcane possessed four Arabidopsis AOx1-type orthologues (SsAOx1a-1d); no sugarcane orthologue corresponding to Arabidopsis AOx2-type genes was identified. Phylogenetic and expression analyses suggested that AtAOx1d does not belong to the AOx1-type family but forms a new (AOx3-type) family. Tissue-enriched expression profiling revealed that uncoupling protein genes were expressed more ubiquitously than the alternative oxidase genes. Distinct expression patterns among gene family members were observed between monocots and dicots and during chilling stress. These findings suggest that the members of each energy-dissipating system are subject to different cell or tissue/organ transcriptional regulation. As a result, plants may respond more flexibly to adverse biotic and abiotic conditions, in which oxidative stress is involved.

Amino Acid Sequence↗
PubMed2025

Coalescing single-cell genomes and transcriptomes to decode breast cancer progression.

Understanding epithelial lineages of breast cancer and genotype-phenotype relationships requires direct measurements of the genome and transcriptome of the same single cells at scale. To achieve this, we developed wellDR-seq, a high-genomic-resolution, high-throughput method to simultaneously profile the genome and transcriptome of thousands of single cells. We profiled 33,646 single cells from 12 estrogen-receptor-positive breast cancers and identified ancestral subclones in multiple patients that showed a luminal hormone-responsive lineage, indicating a potential cell of origin. In contrast to bulk studies, wellDR-seq enabled the study of subclone-level gene-dosage relationships, which showed near-linear correlations in large chromosomal segments and extensive variation at the single-gene level. We identified dosage-sensitive and dosage-insensitive genes, including many breast cancer genes as well as sporadic copy-number aberrations in non-cancer cells. Overall, these data reveal complex relationships between copy number and gene expression in single cells, improving our understanding of breast cancer progression.

Breast Neoplasms↗
PubMed2007

Molecular characterization of human multiple myeloma cell lines by integrative genomics: insights into the biology of the disease.

To investigate the patterns of genetic lesions in a panel of 23 human multiple myeloma cell lines (HMCLs), we made a genomic integrative analysis involving FISH, and both gene expression and genome-wide profiling approaches. The expression profiles of the genes targeted by the main IGH translocations showed that the WHSC1/MMSET gene involved in t(4;14)(p16;q32) was expressed at different levels in all of the HMCLs, and that the expression of the MAF gene was not restricted to the HMCLs carrying t(14;16)(q32;q23). Supervised analyses identified a limited number of genes specifically associated with t(4;14) and involved in different biological processes. The signature related to MAF/MAFB expression included the known MAF target genes CCND2 and ITGB7, as well as genes controlling cell shape and cell adhesion. Genome-wide DNA profiling allowed the identification of a gain on chromosome arm 1q in 88% of the analyzed cell lines, together with recurrent gains on 8q, 18q, 7q, and 20q; the most frequent deletions affected 1p, 13q, 17p, and 14q; and almost all of the cell lines presented LOH on chromosome 13. Two hundred and twenty-two genes were found to be simultaneously overexpressed and amplified in our panel, including the BCL2 locus at 18q21.33. Our data further support the evidence of the genomic complexity of multiple myeloma and reinforce the role of an integrated genomic approach in improving our understanding of the molecular pathogenesis of the disease. This article contains Supplementary Material available at http://www.interscience.wiley.com/jpages/1045-2257/suppmat.

Cell Line, Tumor↗
PubMed2004

Genomic regionality in rates of evolution is not explained by clustering of genes of comparable expression profile.

In mammalian genomes, linked genes show similar rates of evolution, both at fourfold degenerate synonymous sites (K4) and at nonsynonymous sites (KA). Although it has been suggested that the local similarity in the synonymous substitution rate is an artifact caused by the inclusion of disparately evolving gene pairs, we demonstrate here that this is not the case: after removal of disparately evolving genes, both (1) linked genes and (2) introns from the same gene have more similar silent substitution rates than expected by chance. What causes the local similarity in both synonymous and nonsynonymous substitution rates? One class of hypotheses argues that both may be related to the observed clustering of genes of comparable expression profile. We investigate these hypotheses using substitution rates from both human-mouse and mouse-rat comparisons, and employing three different methods to assay expression parameters. Although we confirm a negative correlation of expression breadth with both K4 and KA, we find no evidence that clustering of similarly expressed genes explains the clustering of genes of comparable substitution rates. If gene expression is not responsible, what about other causes? At least in the human-mouse comparison, the local similarity in KA can be explained by the covariation of KA and K4. As regards K4, our results appear consistent with the notion that local similarity is due to processes associated with meiotic recombination.

Animals↗
PubMed2026

Machine learning-guided risk stratification in elderly AML based on genomic, immunophenotypic and therapeutic profiles.

BACKGROUND: Elderly patients with acute myeloid leukemia (AML) exhibit considerable biological and clinical heterogeneity, hindering precise prognosis. Existing prognostic systems inadequately capture the complexity of elderly AML due to their reliance on data from younger cohorts and omission of key factors like immunophenotypic markers and therapeutic profiles. This study aimed to develop and internally validate a machine learning-based prognostic model specifically tailored to elderly AML patients. METHODS: A total of 156 patients were analyzed using a two-stage modeling strategy. Clinical and genomic variables were modeled first, followed by independent analysis of immunophenotypic features. Feature selection was performed using multilayer perceptron (MLP) and random forest (RF), while multivariate Cox regression was used for final model construction. Internal validation was conducted using 1000 bootstrap iterations to assess model stability and performance. RESULTS: The model demonstrated strong predictive performance, with a concordance index (C-index) of 0.702. Time-dependent area under the curve (AUC) and calibration plots confirmed accurate prediction of 1-, 3-, and 5-year overall survival. Decision curve analysis indicated favorable net benefit across a range of threshold probabilities. Key independent prognostic factors identified included TP53 mutations, high CD13 expression, and IDH2 mutations. CONCLUSION: This model provides a robust and interpretable tool for individualized risk stratification in elderly AML. By integrating genomic, immunophenotypic, and therapeutic variables, it may help optimize treatment decisions and improve outcomes for this vulnerable population. Future efforts should focus on external validation and integration of dynamic biomarkers.

Humans↗
PubMed2006

Global expression profiles in human normal and aneurysmal abdominal aorta based on two distinct whole genome microarray platforms.

Abdominal aortic aneurysms (AAA) are the thirteenth cause of death in the United States. The etiology of the disease is yet largely unknown, although several environmental risk factors (e.g., smoking) have been identified and the search for finding genetic risk factors has been initiated. The purpose of our study was to gain insight into the pathobiology of AAA by determining which genes are expressed in the abdominal aorta under either the diseased or normal states, thereby generating the whole-genome-wide expression profiles for these conditions.

Aortic Aneurysm, Abdominal↗
PubMed2006

Pituitary tumours: findings from whole genome analyses.

Pituitary tumours are common intracranial neoplasms that cause significant morbidity through mass effects and/or the inappropriate secretion of pituitary hormones. Despite a considerable literature detailing potential pathogenic changes in these tumours, their aetiology remains largely unresolved. Recent studies have employed genome-wide profiling towards the identification of novel genes and pathways that are inappropriately expressed or regulated in this tumour type. The techniques employed vary in their complexity and interpretation; however, many of the findings from these types of studies have identified novel genes with potential and, in some cases, proven roles in pituitary tumorigenesis. These studies include comparative genomic hybridization, whole genome-wide allelotyping and methodologies for identification of novel genes associated with epigenetic silencing. In addition, differential display methodologies have been instrumental in the identification of transcripts inappropriately expressed including, pituitary tumour transforming gene, growth arrest and DNA damage-inducible protein (GADD)45gamma and a maternal expressed gene 3 isoform, which in some cases have proven roles in pituitary tumorigenesis. Although few studies of whole genome transcript analysis, as determined by microarray or gene-chip technologies, are reported, these studies of human pituitary, in some cases combined with proteomics, are yielding useful data. In addition, these types of investigation have been applied to several animal models of pituitary tumorigenesis, and in these cases novel genes are highlighted as showing significant change. The identification of the initiating events responsible for the transformation of a normal pituitary cell into one with unrestrained proliferative capacity has so far eluded us. No doubt, these new technologies allowing an essentially unbiased genome-wide analysis, perhaps in combination with animal models that display a preceding hyperplasia, will allow us to identify genes critical to tumour evolution and progression.

DNA Damage↗
PubMed2005

Genomic and protein expression profiling identifies CDK6 as novel independent prognostic marker in medulloblastoma.

PURPOSE: Medulloblastoma is the most common malignant brain tumor in children. Despite multimodal aggressive treatment, nearly half of the patients die as a result of this tumor. Identification of molecular markers for prognosis and development of novel pathogenesis-based therapies depends crucially on a better understanding of medulloblastoma pathomechanisms. PATIENTS AND METHODS: We performed genome-wide analysis of DNA copy number imbalances in 47 medulloblastomas using comparative genomic hybridization to large insert DNA microarrays (matrix-CGH). The expression of selected candidate genes identified by matrix-CGH was analyzed immunohistochemically on tissue microarrays representing medulloblastomas from 189 clinically well-documented patients. To identify novel prognostic markers, genomic findings and protein expression data were correlated to patient survival. RESULTS: Matrix-CGH analysis revealed frequent DNA copy number alterations of several novel candidate regions. Among these, gains at 17q23.2-qter (P < .01) and losses at 17p13.1 to 17p13.3 (P = .04) were significantly correlated to poor prognosis. Within 17q23.2-qter and 7q21.2, two of the most frequently gained chromosomal regions, confined amplicons were identified that contained the PPM1D and CDK6 genes, respectively. Immunohistochemistry revealed strong expression of PPM1D in 148 (88%) of 168 and CDK6 in 50 (30%) of 169 medulloblastomas. Overexpression of CDK6 correlated significantly with poor prognosis (P < .01) and represented an independent prognostic marker of overall survival on multivariate analysis (P = .02). CONCLUSION: We identified CDK6 as a novel molecular marker that can be determined by immunohistochemistry on routinely processed tissue specimens and may facilitate the prognostic assessment of medulloblastoma patients. Furthermore, increased protein-levels of PPM1D and CDK6 may link the TP53 and RB1 tumor suppressor pathways to medulloblastoma pathomechanisms.

Biomarkers, Tumor↗
PubMed2006

Chemosensory proteins in the honey bee: Insights from the annotated genome, comparative analyses and expressional profiling.

Small chemosensory proteins (CSPs) belong to a conserved, but poorly understood protein family that has been implicated in transporting chemical stimuli within insect sensilla. However, their expression patterns suggest that these molecules are also critical for other functions including early development. Here we used both bioinformatics and experimental approaches to characterize the CSP gene family in a social insect, the Western honey bee Apis mellifera, and then compared its members to CSPs in other arthropods. The number of CSPs in the honey bee genome (six) is similar to that found in the sequenced dipteran species (four-seven), but is much lower than the number of CSPs in the moth or in the beetle (around 20 each). These differences seem to be the result of lineage specific expansions. Our analysis of CSPs in a number of arthropods reveals a conserved gene family found in both Mandibulates and Chelicerates. Expressional profiling in diverse tissues and throughout development reveals broader than expected patterns of expression with none of the CSPs restricted to the antennae and one found only in the queen ovaries and in embryos. We conclude that CSPs are multifunctional context-dependent proteins involved in diverse cellular processes ranging from embryonic development to chemosensory signal transduction. Some CSPs may function in cuticle synthesis, consistent with their evolutionary origins in the arthropods.

Amino Acid Sequence↗
PubMed2000

Mining genomes and mapping proteomes: identification and characterization of protein subunit vaccines.

Currently, there is an extensive and unprecedented effort to obtain the complete nucleotide sequence of the complex genomes of many micro-organisms. In this post-genomic era, based on the availability of the entire genome sequence of an organism, three new disciplines of molecular biology have emerged: genomics, transcriptional profiling and proteomics. All these technologies have the potential to accelerate the process of identifying protective protein antigens as subunit vaccine targets as well as validating and extending the range of available candidate antigens. The progress of these technologies has led to the origination of the science of bioinformatics for management and critical evaluation of the large amount of information generated. Although genomics, transcriptional profiling and proteomics are each based on different principles, there is considerable synergy between them. Appropriate application of any one, or a combination of two or more of these approaches, coupled with bioinformatics, would allow identification of a short-list of vaccine candidates from the entire list of several hundreds to thousands of proteins encoded by the genome. These candidates would then require usual channelling through the subsequent process involving recombinant expression, purification and testing for immunogenicity and protective efficacy.

Animals↗