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At least 1,387 records · Page 77Linked to original sources
PubMed1974

Genetic mapping in Bacillus subtilis by 5-bromouracil sensitization to ultraviolet inactivation of transforming activities.

A new method for chromosome mapping of Bacillus subtilis Marburg is presented which is based on the sensitization to ultraviolet irradiation of transforming deoxyribonucleic acid that has incorporated 5-bromouracil instead of thymine. Deoxyribonucleic acid was extracted at intervals from the outgrowing spores of a thymine-requiring mutant incubated with 5-bromodeoxyuridine and subjected to a definite dose of ultraviolet irradiation. The residual activities of various genetic markers were assayed by transformation. The marker activity of deoxyribonucleic acid that had incorporated 5-bromodeoxyuridine was approximately 10 times as sensitive to ultraviolet irradiation as that of normal deoxyribonucleic acid. The markers proximal to the replication origin were sensitized at earlier times of outgrowth than distal markers. The chromosome replication in outgrowing spores was sufficiently synchronous and allowed the definite determination of when a marker became sensitized by incorporation of 5-bromodeoxyuridine. The time, designated "sensitization time," was estimated by plotting the logarithmic values of relative residual activities versus incubation times. The map constructed with sensitization times as a measurement showed good agreement with those constructed by other methods. The replication of the chromosome under the described conditions appeared to occur in the following marker order: (purA, hisA)-(purB)-(thr, pyrA)-(metC)-(leuA)-(lys, trpC, metB).

Bacillus subtilis↗
PubMed1993

Strain identification of Mycobacterium tuberculosis by DNA fingerprinting: recommendations for a standardized methodology.

DNA fingerprinting of Mycobacterium tuberculosis has been shown to be a powerful epidemiologic tool. We propose a standardized technique which exploits variability in both the number and genomic position of IS6110 to generate strain-specific patterns. General use of this technique will permit comparison of results between different laboratories. Such comparisons will facilitate investigations into the international transmission of tuberculosis and may identify specific strains with unique properties such as high infectivity, virulence, or drug resistance.

Base Sequence↗
PubMed1994

A new method for identification of Trichomonas vaginalis by fluorescent DNA in situ hybridization.

The protozoan flagellate Trichomonas vaginalis is responsible for human trichomoniasis, one of the most widespread sexually transmitted diseases in the world. Several methods are currently used for laboratory diagnosis, including direct microscopic observation, cell culture, immunological techniques, and more recently, DNA probing and gene amplification. This report describes an in situ hybridization technique with specific DNA probes labeled with either biotin, rhodamine, or fluorescein for detection of T. vaginalis with fluorescence microscopy. Repetitive DNA sequences were evident in the nuclei of the protozoa as intensively fluorescent regions, giving a spotted pattern. No cross-reactivity between the probes and the DNAs of mammalian cells, yeasts, or bacteria was noted. This technique is potentially useful for the diagnosis of human trichomoniasis in clinical samples.

Animals↗
PubMed1998

Computerized analysis of restriction fragment length polymorphism patterns: comparative evaluation of two commercial software packages.

Two computerized restriction fragment length polymorphism pattern analysis systems, the BioImage system and the GelCompar system (Molecular Analyst Fingerprinting Plus in the United States), were compared. The two systems use different approaches to compare patterns from different gels. In GelCompar, a standard reference pattern in one gel is used to normalize subsequent gels containing lanes with the same reference pattern. In BioImage, the molecular sizes of the fragments are calculated from size standards present in each gel. The molecular size estimates obtained with the two systems for 12 restriction fragments of phage lambda were between 97 and 101% of their actual sizes, with a standard deviation of less than 1% of the average estimated size for most fragments. At the window sizes used for analysis, the GelCompar system performed somewhat better than BioImage in identifying visually identical patterns generated by electrophoretic separation of HhaI-restricted DNA of Listeria monocytogenes. Both systems require the user to make critical decisions in the analysis. It is very important to visually verify that the systems are finding all bands in each lane and that no artifacts are being detected; both systems allow manual editing. It is also important to verify results obtained in the pattern matching or clustering portions of the analysis.

Bacteriophage lambda↗
PubMed1976

The relationship between chromatid interference and the mapping function.

A formula for a general mapping function involving only the number of chiasmata between two points on the chromosome and the average excess of four-stranded double exchanges over two-stranded double exchanges is derived. A formula is also given for deriving the proportion of three-stranded double exchanges after any given number of chiasmata; this is related to mapping for linkage with the centromere. It is shown that this proportion tends to a limit of 2/3 after a large number of chiasmata, whether or not chromatid interference is operating.

Chromatids↗
PubMed1998

Body surface mapping during pacing at multiple sites in the human atrium: P-wave morphology of ectopic right atrial activation.

BACKGROUND: The morphology and polarity of the P wave on 12-lead ECG are of limited clinical value in localizing ectopic atrial rhythms. It was the aim of this study to assess the spatial resolution of body surface P-wave integral mapping in identifying the site of origin of ectopic right atrial (RA) impulse formation in patients without structural atrial disease. METHODS AND RESULTS: Sixty-two-lead ECG recordings were obtained during RA pacing at 86 distinct endocardial sites in nine patients with normal biatrial anatomy. After P-wave integral maps were generated for each paced activation sequence, 17 groups with nearly identical map features were visually selected, and a mean P-wave integral map was computed for each group. Supportive statistical analysis to corroborate qualitative group selection was performed by assessment of (1) intragroup pattern uniformity by use of jackknife correlation coefficient analysis of the integral maps contained in each group and (2) intergroup pattern variability by use of the calculation of cross correlations between the 17 mean integral maps. The spatial resolution of paced P-wave body surface mapping in the right atrium was obtained by estimating the area size of endocardial segments with nearly identical P-wave integral maps by use of a biplane fluoroscopic method to compute the three-dimensional position of each pacing site. The latter approach yielded a mean endocardial segment size of 3.5+/-2.9 cm2 (range, 0.79 to 10.75 cm2). CONCLUSIONS: Use of the P-wave morphology on the 62-lead surface ECG in patients with normal biatrial anatomy allows separation of the origin of ectopic RA impulse formation into one of 17 different endocardial segments with an approximated area size of 3.5 cm2. This database of paced P-wave integral maps provides a versatile clinical tool to perform detailed noninvasive localization of right-sided atrial tachycardia before radiofrequency catheter ablation.

Adult↗
PubMedDate not supplied

Development and assignment of bovine-specific PCR systems for the Texas nomenclature marker genes and isolation of homologous BAC probes.

In 1996, Popescu et al. published the Texas standard nomenclature of the bovine karyotype in which 31 marker genes, already mapped in man, were chosen to permit unambiguous identification and numbering of each bovine chromosome. However, specific PCR systems were not available for each marker gene thus preventing the assignment of part of these markers by somatic cell hybrid analysis. In addition, some difficulties remained with the nomenclature of BTA25, BTA27 and BTA29. In this work, specific PCR systems were developed for each of the marker genes except VIL1 (see results), from either existing bovine or human sequences, and a bovine BAC library was screened to obtain the corresponding BAC clones. These PCR systems were used successfully to confirm the assignment of each marker gene (except for LDHA, see results) by analysis on the INRA hamster-bovine somatic cell hybrid panel. The difficulties observed for LDHA and VIL1 are probably due to the fact that these genes belong to large gene families and therefore suggest that they may not be the most appropriate markers for a standardisation effort. This panel of BACs is available to the scientific community and has served as a basis for the establishment of a revised standard nomenclature of bovine chromosomes.

Animals↗
PubMed1981

On current topics and future prospects in electrocardiography.

Some selected topics and future prospects in electrocardiography were stated, namely, electrocardiograph, computer interpretation of electrocardiogram, body surface mapping and electrocardiography at large. Special attention was paid to computer application to signal processing and decision making with respect to electrocardiography. A brief review for inverse problem in electrocardiography was made as well. In regard to body surface mapping, another way of expression of the maps was proposed where, instead of routine isopotential map, isochrone map for ventricular activation time of QRS complexes was used for representing the ventricular electrophysiologic activities.

Computers↗
PubMed2002

Damage recovery pathways in Saccharomyces cerevisiae revealed by genomic phenotyping and interactome mapping.

We have generated a genomic phenotyping database identifying hundreds of Saccharomyces cerevisiae genes important for viable cellular recovery after mutagen exposure. Systematic phenotyping of 1,615 gene deletion strains produced distinctive signatures for each of four mutagens. Integration of the phenotyping database with mutagen-induced transcriptional profiling data demonstrated that being transcriptionally responsive to a mutagen does not predict whether or not a gene contributes to recovery from exposure to that mutagen. Computational integration of the database with 4,025 interacting proteins, comprising the yeast interactome, identified several multiprotein networks important for damage recovery. Some networks were associated with DNA metabolism and cell cycle control functions, but most were associated with unexpected functions such as cytoskeleton remodeling, chromatin remodeling, protein, RNA, and lipid metabolism. Hence, a plethora of responses other than the DNA damage response is important for recovery. These network mapping results demonstrate how systematic phenotypic assays may be linked directly to underlying molecular mechanisms.

Cell Division↗
PubMed2003

The dystrophin associated protein complex in zebrafish.

Many cases of muscular dystrophy in humans are caused by mutations in members of the dystrophin associated protein complex (DAPC). Zebrafish are small vertebrates whose bodies are composed predominantly of skeletal muscle, making them attractive models for studying mammalian muscle disorders. Potential orthologs to most of the human DAPC proteins have been found in zebrafish by database screening. Expression of the sarcoglycans, dystroglycan and dystrophin has been confirmed by western blotting. Immunohistochemical and biochemical techniques localize these proteins to the muscle cell membrane in adult zebrafish. Morpholino (MO) experiments designed to inhibit the translation of dystrophin mRNA produce juvenile zebrafish that are less active than zebrafish injected with control morpholinos. Western blot analysis of the dystrophin morpholino-injected zebrafish shows concurrent reduction of dystrophin and the sarcoglycans, suggesting that these proteins, like those in mammals, are part of a complex whose integrity is dependent on dystrophin expression. These results indicate that the zebrafish is an excellent animal model in which to approach the study of dystrophin and its associated proteins.

Amino Acid Sequence↗
PubMed2003

Cloning and chromosomal characterization of the 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3 gene (PFKFB3, iPFK2).

PFKFB (6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase) is a bifunctional enzyme that regulates the steady-state concentration of fructose-2,6-bisphosphate, which is a potent activator of the key regulatory enzyme of glycolysis, phosphofructokinase. PFKFB3 (iPFK2) is one of four tissue-specific PFKFB isozymes that have been identified to date. PFKFB3 also has been implicated in the high glycolytic rate of cancer cells that occurs despite adequate oxygen, a phenomenon known as the Warburg effect. We have isolated and characterized the human PFKFB3 genomic sequence, which spans a region of 32.5 kb and which has a single chromosomal locus. Determination of the exon-intron splice junctions established that PFKFB3 is encoded by 19 exons of which only 15 are normally expressed. Exon sizes range between 23 and 208 bp, the largest intron is 10,286 bp long. The full-length human PFKFB3 open reading frame is 4,675 bp long and encodes a 590 aa protein with a predicted molecular weight of 66.9 kDa and an isoelectric point of 8.64. Fluorescence in situ hybridization analysis localized the human PFKFB3 gene to chromosome 10p15.3-p15.2, and its locus is 3 million bp centromeric to PFKP, the platelet-type phosphofructokinase. PFKFB3 has been shown to be abundantly expressed in human tumors and its expression linked to long-standing observations concerning the apparent coupling of enhanced glycolysis and cell proliferation.

Amino Acid Sequence↗
PubMed2006

Transcranial magnetic stimulation: the method and application.

Transcranial magnetic stimulation is a noninvasive method for stimulation of brain that is based on the ability of magnetic field to penetrate skull and brain meninges, subsequently inducing electric current in the brain tissues that produces neuronal depolarization and generation of action potentials. Moreover, transcranial magnetic stimulation has effects on neurochemical and synaptic processes in neurons. Due to its easy use and relatively fair side effects, nowadays, transcranial magnetic stimulation is widely used in neurosciences and medicine. The main areas of transcranial magnetic stimulation application are: 1) the investigation of cortical and spinal excitability, 2) the investigation of neuronal plasticity, 3) the investigation of neuronal connectivity, 4) functional mapping, and 5) the treatment of some neurological and psychiatric disorders. Transcranial magnetic stimulation alone or in combination with other noninvasive neuroimaging (PET--positron emission topography, MRI--magnetic resonance imaging) and neurofunctional (EEG--electroencephalography, ERP--event-related potentials, fMRI--functional magnetic resonance imaging) methods allows conducting research on brain functions. Thus, transcranial magnetic stimulation is suitable as a diagnostic tool in neurologic and neuropsychiatric brain research.

Action Potentials↗
PubMed1978

[Gene dosage and chromosome enzymatic markers].

Data are tabulated on the number of nomenclature current abbreviations, the occurence of multiple gene loci and corresponding polypeptide chains, and chromosomal assignment of 114 enzymes. Gene dose effect measurement is dependent upon several properties of the enzyme which are also listed: tissue and subcellular distribution, subunit number, interloci hybrids, genetic polymorphism, qualitative and quantitative methods of detection. The possibilities and limits of the concept of a gene-dose relationship, for the detection of carriers of chromosomal aberrations, and also for chromosomal assignment are discussed.

Chromosome Mapping↗