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Alpha-periodicity analysis of small multidrug resistance (SMR) efflux transporters.

Proteins in the small multidrug resistance (SMR) family of transport proteins are about 110 amino acids in length and are predicted to have four transmembrane helices. This family is divided into a two groups, one of which we have referred to as small multidrug pumps (Smp) and confer resistance to a wide variety of quaternary ammonium compounds through a proton-drug efflux antiport mechanism. Members of the second group within this family have, as yet, not had their substrate profile characterized and are referred to as Sug proteins. Alpha-periodicity analysis was conducted on a set of six homologous proteins of the SMR family consisting of three established Smp and three Sug proteins. Several amino acid properties were used in the analysis including hydropathy, variability, and a substitution matrix for lipid exposed amino acids. The scanning window was varied between 8 and 14 residues and the alpha-periodicity was calculated from the peaks in the Fourier transform power spectra in the region between 3.0 and 4.3 residues/turn. This analysis adds to the hydropathy analysis to give a more confident prediction of which residues are within the lipid bilayer for each of the four transmembrane helices. Information was also obtained that allowed for the identification of zones within each transmembrane helix that face the interior of the helical bundle on one side and are lipid exposed on the other face.

Amino Acid Sequence↗

Accessory DNA in the genomes of representatives of the Escherichia coli reference collection.

Different strains of the Escherichia coli reference collection (ECOR) differ widely in chromosomal size. To analyze the nature of the differential gene pool carried by different strains, we have followed an approach in which random amplified polymorphic DNA (RAPD) was used to generate several PCR fragments. Those present in some but not all the strains were screened by hybridization to assess their distribution throughout the ECOR collection. Thirteen fragments with various degrees of occurrence were sequenced. Three of them corresponded to RAPD markers of widespread distribution. Of these, two were housekeeping genes shown by hybridization to be present in all the E. coli strains and in Salmonella enterica LT2; the third fragment contained a paralogous copy of dnaK with widespread, but not global, distribution. The other 10 RAPD markers were found in only a few strains. However, hybridization results demonstrated that four of them were actually present in a large selection of the ECOR collection (between 42 and 97% of the strains); three of these fragments contained open reading frames associated with phages or plasmids known in E. coli K-12. The remaining six fragments were present in only between one and four strains; of these, four fragments showed no similarity to any sequence in the databases, and the other two had low but significant similarity to a protein involved in the Klebsiella capsule synthesis and to RNA helicases of archaeal genomes, respectively. Their percent GC, dinucleotide content, and codon adaptation index suggested an exogenous origin by horizontal transfer. These results can be interpreted as reflecting the presence of a large pool of strain-specific genes, whose origin could be outside the species boundaries.

Bacteriology↗

Analysis of chicken serum proteome and differential protein expression during development in single-comb White Leghorn hens.

Serum is believed to harbor thousands of distinct proteins that are either actively secreted or leak from various blood cells or tissues. Exploring protein composition in serum may accelerate the discovery of novel protein biomarkers for specific economic traits in livestock species. This study analyzed serum protein composition to establish a 2-DE reference map, and monitored protein dynamics of single-comb White Leghorn hens at 8, 19 and 23 weeks after hatching. A total of 119 CBB-stained and 315 silver-stained serum protein spots were analyzed by MALDI-TOF MS. Of these, 98 CBB-stained and 94 silver-stained protein spots were significantly matched to existing chicken proteins. The identified spots represented 30 distinctive proteins in the serum of laying hens. To compare protein expression during development, expression levels of 47 protein spots were quantified by relative spot volume with Melanie 3 software. Ten protein spots increased and 3 protein spots decreased as hen age increased. Previous research has suggested that some of these proteins play critical roles in egg production. The differentially expressed proteins with unknown identities will be valuable candidates for further explorations of their roles in egg production of laying hens.

Age Factors↗

Analysis of multiple single nucleotide polymorphisms of candidate genes related to coronary heart disease susceptibility by using support vector machines.

Coronary heart disease (CHD) is a complex genetic disease involving gene-environment interaction. Many association studies between single nucleotide polymorphisms (SNPs) of candidate genes and CHD have been reported. We have applied a new method to analyze such relationships using support vector machines (SVMs), which is one of the methods for artificial neuronal network. We assumed that common haplotype implicit in genotypes will differ between cases and controls, and that this will allow SVM-derived patterns to be classifiable according to subject genotypes. Fourteen SNPs of ten candidate genes in 86 CHD patients and 119 controls were investigated. Genotypes were transformed to a numerical vector by giving scores based on difference between the genotypes of each subject and the reference genotypes, which represent the healthy normal population. Overall classification accuracy by SVMs was 64.4% with a receiver operating characteristic (ROC) area of 0.639. By conventional analysis using the chi2 test, the association between CHD and the SNP of the scavenger receptor B1 gene was most significant in terms of allele frequencies in cases vs. controls (p = 0.0001). In conclusion, we suggest that the application of SVMs for association studies of SNPs in candidate genes shows considerable promise and that further work could be usefully performed upon the estimation of CHD susceptibility in individuals of high risk.

Alleles↗

Comprehensive processing, display and analysis for in vivo MR spectroscopic imaging.

Image reconstruction for magnetic resonance spectroscopic imaging (MRSI) requires specialized spatial and spectral data processing methods and benefits from the use of several sources of prior information that are not commonly available, including MRI-derived tissue segmentation, morphological analysis and spectral characteristics of the observed metabolites. In addition, incorporating information obtained from MRI data can enhance the display of low-resolution metabolite images and multiparametric and regional statistical analysis methods can improve detection of altered metabolite distributions. As a result, full MRSI processing and analysis can involve multiple processing steps and several different data types. In this paper, a processing environment is described that integrates and automates these data processing and analysis functions for imaging of proton metabolite distributions in the normal human brain. The capabilities include normalization of metabolite signal intensities and transformation into a common spatial reference frame, thereby allowing the formation of a database of MR-measured human metabolite values as a function of acquisition, spatial and subject parameters. This development is carried out under the MIDAS project (Metabolite Imaging and Data Analysis System), which provides an integrated set of MRI and MRSI processing functions. It is anticipated that further development and distribution of these capabilities will facilitate more widespread use of MRSI for diagnostic imaging, encourage the development of standardized MRSI acquisition, processing and analysis methods and enable improved mapping of metabolite distributions in the human brain.

Algorithms↗

Genetic predisposition to breast cancer: a surgical perspective.

BACKGROUND: Molecular alterations in proto-oncogenes, tumour suppressor genes, and genes that function in DNA damage recognition and repair are considered to be hallmarks of a carcinogenic process, including breast carcinogenesis. METHODS: A computer-assisted search of the English literature (Medline database, 1990-1999) was performed, followed by a manual search of the reference list of pertinent articles retrieved. RESULTS: Hereditary breast cancer accounts for 5-10 per cent of all breast cancer cases. About 90 per cent of hereditary breast cancers involve mutation of the BRCA1 and/or BRCA2 genes. Other cancer-related genes (including myc, c-erbB2, Tsg101 and Mdgi) are involved in breast carcinogenesis, but they do not give rise to familial breast cancer syndromes. Risk estimation is the most important clinical implication. Management options for the high-risk mutation carriers include cancer surveillance and preventive strategies (prophylactic surgery or chemoprevention). CONCLUSION: Despite inadequate knowledge about the genetic predisposition to breast cancer and its clinical implications, the demand for genetic testing is likely to expand rapidly. In addition to risk estimation, cancer surveillance and preventive strategies, gene therapy offers a new and theoretically attractive approach to breast cancer management.

BRCA2 Protein↗

Expression patterns and action analysis of genes associated with blood coagulation responses during rat liver regeneration.

AIM: To study the blood coagulation response after partial hepatectomy (PH) at transcriptional level. METHODS: After PH of rats, the associated genes with blood coagulation were obtained through reference to the databases, and the gene expression changes in rat regenerating liver were analyzed by the Rat Genome 230 2.0 array. RESULTS: It was found that 107 genes were associated with liver regeneration. The initially and totally expressing gene numbers occurring in initiation phase of liver regeneration (0.5-4 h after PH), G0/G1 transition (4-6 h after PH), cell proliferation (6-66 h after PH), cell differentiation and structure-function reconstruction (66-168 h after PH) were 44, 11, 58, 7 and 44, 33, 100, 71 respectively, showing that the associated genes were mainly triggered in the forepart and prophase, and worked at different phases. According to their expression similarity, these genes were classified into 5 groups: only up-, predominantly up-, only down-, predominantly down-, up- and down-regulation, involving 44, 8, 36, 13 and 6 genes, respectively, and the total times of their up- and down-regulation expression were 342 and 253, respectively, demonstrating that the number of the up-regulated genes was more than that of the down-regulated genes. Their time relevance was classified into 15 groups, showing that the cellular physiological and biochemical activities were staggered during liver regeneration. According to gene expression patterns, they were classified into 29 types, suggesting that their protein activities were diverse and complex during liver regeneration. CONCLUSION: The blood coagulation response is enhanced mainly in the forepart, prophase and anaphase of liver regeneration, in which the response in the forepart, prophase of liver regeneration can prevent the bleeding caused by partial hepatectomy, whereas that in the anaphase contributes to the structure-function reorganization of regenerating liver. In the process, 107 genes associated with liver regeneration play an important role.

Animals↗

Translational research on the way to effective therapy for Alzheimer disease.

CONTEXT: Alzheimer disease (AD) is a major public health issue with a prediction of 12 million Americans being affected by 2025 from the present 4 million. Molecular and genetic findings have provided significant insights into the roles that amyloid, tau, and apolipoprotein E isoforms have in the causation of AD. A central issue in AD pathogenesis is the amyloid cascade hypothesis. It states that abnormal amyloid processing and accumulation is the primary causative factor of AD and other associated neuropathologic abnormalities are of secondary consequence. It is presented to provide the rationale for novel drug and vaccination therapeutic strategies. Future research directed at prediction and prevention of AD through a genomic and proteomic analysis with identification of multiple polymorphic genes that interact, resulting in increased risk for late-onset AD, are the realistic and ultimate goals. A new approach for drug development is required, one that will emphasize a genomic and proteomic analysis to identify at-risk gene sets whose genetic expression is sufficient to cause late onset, sporadic AD. Prediction and prevention of disease prior to clinical signs and symptoms are the goals. OBJECTIVE: A review and analysis from electronic literature databases and subsequent reference searches of the molecular genetic data. including pertinent genetic mutations and abnormal biochemical findings causal of AD, are cited. The amyloid cascade hypothesis, the contributions of apolipoprotein E, and hyperphosphorylated tau are discussed as to their roles in pathogenesis. Molecular targets for potential drug and vaccination therapies are cited from a critical assessment of the molecular and biomedical data. These data form the basis for rational, target-specific drug and vaccination therapies currently employed and planned for the near future. Phase 2 and 3 clinical trial results of drug and vaccination therapies are cited. CONCLUSIONS: A new approach is needed as current pharmacologic therapy directed at symptomatic relief has proved to be marginally effective. The genomic and proteomic basis of AD will be defined in the near future, and corresponding molecular therapeutic targets will be identified. Genomic neurology has arrived and its application to resolving AD is our best hope.

Alzheimer Disease↗

Prognostic factors in gastric cancer.

BACKGROUND: Despite gastric cancer being common, its prognosis has not been improved significantly in recent years. Now, greater insight has been gained into the biological properties of tumour cells, how they become malignant and what mechanisms they may use to invade and metastasize. This involves tumour-associated protease systems, loss or mutation of adhesion molecules and changes in genetics. The view of gastric cancer is changing: it is not only a solid tumour but also exhibits a minimal residual disease component even in the early stages of disease. Such biological tumour characteristics may provide new prognostic factors and also potential new therapeutic options. METHODS: This is an update of prognostic factors in gastric cancer, emphasizing new biological features, some of which have been investigated by this group over the past few years. Current results are discussed in the light of 212 references obtained from the Medline database from 1979 to 1997. RESULTS: There is high probability that some of the factors reviewed, such as c-erbB-2, individual course and phenotyping of disseminated tumour cells will become significant new prognostic variables. This is true also, to a lesser extent, of cathepsin D, matrix metalloproteinase 2 combined with activators or tissue inhibitor of metalloproteinases 2, CD44, E-cadherin, p53 and cripto. Plasminogen activator inhibitor 1 (PAI-1), a member of the urokinase-type plasminogen activator (uPA) system, can already be defined as an established new prognostic factor in gastric cancer. CONCLUSION: PAI-1 should be considered prognostically in addition to established tumour classifications. Moreover, the uPA system is a target for future therapeutic concepts. Further analysis of factors describing tumour biology should lead to new, functionally orientated, tumour classifications in gastric cancer.

Cell Adhesion Molecules↗

Use of phylogenetic and phenotypic analyses to identify nonhemolytic streptococci isolated from bacteremic patients.

The aim of this study was to evaluate molecular and phenotypic methods for the identification of nonhemolytic streptococci. A collection of 148 strains consisting of 115 clinical isolates from cases of infective endocarditis, septicemia, and meningitis and 33 reference strains, including type strains of all relevant Streptococcus species, were examined. Identification was performed by phylogenetic analysis of nucleotide sequences of four housekeeping genes, ddl, gdh, rpoB, and sodA; by PCR analysis of the glucosyltransferase (gtf) gene; and by conventional phenotypic characterization and identification using two commercial kits, Rapid ID 32 STREP and STREPTOGRAM and the associated databases. A phylogenetic tree based on concatenated sequences of the four housekeeping genes allowed unequivocal differentiation of recognized species and was used as the reference. Analysis of single gene sequences revealed deviation clustering in eight strains (5.4%) due to homologous recombination with other species. This was particularly evident in S. sanguinis and in members of the anginosus group of streptococci. The rate of correct identification of the strains by both commercial identification kits was below 50% but varied significantly between species. The most significant problems were observed with S. mitis and S. oralis and 11 Streptococcus species described since 1991. Our data indicate that identification based on multilocus sequence analysis is optimal. As a more practical alternative we recommend identification based on sodA sequences with reference to a comprehensive set of sequences that is available for downloading from our server. An analysis of the species distribution of 107 nonhemolytic streptococci from bacteremic patients showed a predominance of S. oralis and S. anginosus with various underlying infections.

Bacteremia↗

A first full outer capsid protein sequence data-set in the Orbivirus genus (family Reoviridae): cloning, sequencing, expression and analysis of a complete set of full-length outer capsid VP2 genes of the nine African horsesickness virus serotypes.

The outer capsid protein VP2 of African horsesickness virus (AHSV) is a major protective antigen. We have cloned full-length VP2 genes from the reference strains of each of the nine AHSV serotypes. Baculovirus recombinants expressing the cloned VP2 genes of serotypes 1, 2, 4, 6, 7 and 8 were constructed, confirming that they all have full open reading frames. This work completes the cloning and expression of the first full set of AHSV VP2 genes. The clones of VP2 genes of serotypes 1, 2, 5, 7 and 8 were sequenced and their amino acid sequences were deduced. Our sequencing data, together with that of the published VP2 genes of serotypes 3, 4, 6 and 9, were used to generate the first complete sequence analysis of all the (sero)types for a species of the Orbivirus genus. Multiple alignment of the VP2 protein sequences showed that homology between all nine AHSV serotypes varied between 47.6 % and 71.4 %, indicating that VP2 is the most variable AHSV protein. Phylogenetic analysis grouped together the AHSV VP2s of serotypes that cross-react serologically. Low identity between serotypes was demonstrated for specific regions within the VP2 amino acid sequences that have been shown to be antigenic and play a role in virus neutralization. The data presented here impact on the development of new vaccines, the identification and characterization of antigenic regions, the development of more rapid molecular methods for serotype identification and the generation of comprehensive databases to support the diagnosis, epidemiology and surveillance of AHS.

African Horse Sickness↗

Diversity and prevalence of Arcobacter spp. in broiler chickens.

Ninety-nine strains of Arcobacter spp., isolated from 10 chicken carcasses purchased from a supermarket and 15 chicken carcasses collected from a poultry abattoir, were speciated using a variety of phenotypic identification methods. All were tested using API Campy test strips and the 16-test (Preston) identification scheme developed for campylobacters. Fifty strains were selected for examination using a more comprehensive probabilistic identification scheme, and the identity of representative strains confirmed by protein profiling using SDS-PAGE. All 25 carcasses yielded Arcobacter butzleri. Three supermarket and 10 abattoir carcasses also carried A. cryaerophilus, and two abattoir carcasses carried A. skirrowii. The API Campy scheme proved unsatisfactory for identifying these strains: only 20 of 99 strains were accurately identified, all of which were A. cryaerophilus, the only Arcobacter sp. included in the database. Moreover, 76 of 99 strains were misidentified. The 16-test scheme identified all the arcobacter strains as A. cryaerophilus, since neither A. butzleri nor A. skirrowii had been described when the scheme was developed. The computer-assisted probabilistic scheme succeeded in identifying all but one strain, the identity of which was clarified by the use of SDS-PAGE. To our knowledge this is the first time that arcobacters other than A. butzleri have been reported in poultry meat or any other food of animal origin. Their high prevalence in poultry products may be of significance to public health.

Animals↗

Analysis of the molecular mechanism underlying di(2-ethylhexyl) phthalate-induced bladder carcinogenesis via network toxicology and molecular docking approaches: An observational study.

This study aims to investigate the toxicity of di(2-ethylhexyl) phthalate (DEHP) and the potential molecular mechanisms of DEHP-induced bladder cancer (BLCA) using network toxicology and molecular docking strategies. The toxicity of DEHP was assessed using Prox-II software, and potential targets for DEHP-induced BLCA were identified by integrating data from ChEMBL database, Search Tool for Interactions of Chemicals, SwissTargetPrediction, GeneCards, Therapeutic Target Database, Online Mendelian Inheritance in Man, and The Cancer Genome Atlas. STRING database and Cytoscape were employed to construct target networks and determine core targets. The expression levels of core targets were analyzed using R. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed on potential and core targets. Molecular docking was carried out using CB-Dock 2 to verify the interactions between DEHP and core targets. A total of 105 potential targets related to DEHP-induced BLCA were identified, from which 7 core targets were selected: cyclin-dependent kinase 1, interleukin 6, cyclin-dependent kinase 2, cyclin B1, Erb-B2 receptor tyrosine kinase 2, cyclin B2, and B-cell lymphoma 2. IL-6 and B-cell lymphoma 2 showed downregulated expression in tumor tissues, while cyclin-dependent kinase 1, cyclin-dependent kinase 2, cyclin B1, Erb-B2 receptor tyrosine kinase 2, and cyclin B2 were upregulated. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses indicated that these targets were enriched in cell signaling and cancer-related pathways. Molecular docking confirmed that DEHP interacts with these core targets. DEHP may promote the development of BLCA by interacting with key proteins and signaling pathways. This study provides a theoretical basis for understanding the molecular mechanisms of DEHP-induced BLCA and offers references for future prevention and treatment strategies.

Diethylhexyl Phthalate↗

Giant magnetoresistive sensors and superparamagnetic nanoparticles: a chip-scale detection strategy for immunosorbent assays.

Thin structures of alternating magnetic and nonmagnetic layers with a total thickness of a few hundred nanometers exhibit a phenomenon known as giant magnetoresistance. The resistance of microfabricated giant magnetoresistors (GMRs) is dependent on the strength of an external magnetic field. This paper examines magnetic labeling methodologies and surface derivatization approaches based on protein-protein binding that are aimed at forming a general set of protocols to move GMR concepts into the bioanalytical arena. As such, GMRs have been used to observe and quantify the immunological interaction between surface-bound mouse IgG and alpha-mouse IgG coated on superparamagnetic particles. Results show the response of a GMR network connected together as a set of two sense GMRs and two reference GMRs in a Wheatstone bridge as a means to compensate for temperature effects. The response can be readily correlated to the amount of the magnetically labeled alpha-mouse IgG that is captured by an immobilized layer of mouse IgG, the presence of which is confirmed with X-ray photoelectron spectroscopy and atomic force microscopy. These results, along with a detailed description of the experimental testing platform, are described in terms of sensitivity, detection limits, and potential for multiplexing.

Animals↗

Rrp15p, a novel component of pre-ribosomal particles required for 60S ribosome subunit maturation.

In eukaryotes ribosome biogenesis required that rRNAs primary transcripts are assembled in pre-ribosomal particles and processed. Protein factors and pre-ribosomal complexes involved in this complex pathway are not completely depicted. The essential ORF YPR143W encodes in yeast for an uncharacterized protein product, named here Rrp15p. Cellular function of Rrp15p has not so far defined even if nucleolar location was referred. With the aim to define the possible role of this orphan gene, we performed TAP-tagging of Rrp15p and investigated its molecular association with known pre-ribosomal complexes. Comparative sucrose gradient sedimentation analyses of yeast lysates expressing the TAP-tagged Rrp15p, strongly indicated that this protein is a component of the pre-60S particles. Northern hybridization, primer extension and functional proteomics on TAP-affinity isolated complexes proved that Rrp15p predominately associated with pre-rRNAs and proteins previously characterized as components of early pre-60S ribosomal particles. Finally, depletion of Rrp15p inhibited the accumulation of 27S and 7S pre-rRNAs and 5.8S and 25S mature rRNA. These results provide the first indication that Rrp15p is a novel factor involved in the early maturation steps of the 60S subunits. Moreover, the identification of the protein kinase CK2 in the Rrp15p-containing pre-ribosomal particles here reported, sustains the link between ribosome synthesis and cell cycle progression.

Amino Acid Sequence↗

Chemogenomics knowledge-based strategies in drug discovery.

In the postgenomic age of drug discovery, targets can no longer be viewed as singular objects having no relationship to one another. All targets are now visible and the systematic exploration of selected target families appears to be a promising way to speed up and further industrialize target-based drug discovery. Chemogenomics refers to such systematic exploration of target families and aims to identify all possible ligands of all target families. Because biology works by applying prior knowledge to an unknown entity, chemogenomics approaches are expected to be especially effective within the previously well-explored target families, for which, in addition to the protein sequence and structure information, considerable knowledge of pharmacologically active structural classes and structure-activity relationships exists. For the new target families, chemical knowledge will have to be generated and beyond biological target validation, the emphasis is on chemistry to provide the molecules with which their novel biology and pharmacology can be studied. Using examples from the previously most successfully explored target families, the GPCR family in particular, we summarize herein our current chemogenomics knowledge-based strategies for drug discovery, which are founded on the high integration of chem and bioinformatics, thereby providing a molecular informatics frame for the exploration of the new target families.

Computational Biology↗

Eliminating superfluous neighbor pairs while threading fold models.

In this paper we address the problem of identifying which of various possible spatial residue-residue neighbor pairs are plausible physical contacts without reference to the native structure side chain geometry. We propose an algorithm that eliminates most of the implausible physical contacts from the fold models. This algorithm exploits the correlations between the amino acid side chain rotamers and the direction of the physical contacts between the amino acid side chains. We use this algorithm to "filter" the score of the sequence-to-structure alignment. Filtering is dynamic, in the sense that the set of neighbor pairs contributing to the alignment score varies during threading. Whether or not a neighbor pair contributes to the score depends on the threaded amino acids. This score filtering improves the accuracy of the predicted sequence-to-structure alignment.

Algorithms↗

Intrinsic protein disorder in complete genomes.

Intrinsic protein disorder refers to segments or to whole proteins that fail to fold completely on their own. Here we predicted disorder on protein sequences from 34 genomes, including 22 bacteria, 7 archaea, and 5 eucaryotes. Predicted disordered segments > or = 50, > or = 40, and > or = 30 in length were determined as well as proteins estimated to be wholly disordered. The five eucaryotes were separated from bacteria and archaea by having the highest percentages of sequences predicted to have disordered segments > or = 50 in length: from 25% for Plasmodium to 41% for Drosophila. Estimates of wholly disordered proteins in the bacteria ranged from 1% to 8%, averaging to 3 +/- 2%, estimates in various archaea ranged from 2 to 11%, plus an apparently anomalous 18%, averaging to 7 +/- 5% that drops to 5 +/- 3% if the high value is discarded. Estimates in the 5 eucarya ranged from 3 to 17%. The putative wholly disordered proteins were often ribosomal proteins, but in addition about equal numbers were of known and unknown function. Overall, intrinsic disorder appears to be a common, with eucaryotes perhaps having a higher percentage of native disorder than archaea or bacteria.

Animals↗