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At least 775 records · Page 43Linked to original sources
PubMed1987

Isolation and genetic analysis of mutations allowing the degradation of furans and thiophenes by Escherichia coli.

Successive mutations of Escherichia coli yielded a strain that was able to degrade a variety of heterocyclic oxygen- and sulfur-containing ring compounds. In particular, this strain could use both furan-2-carboxylic acid and thiophene-2-carboxylic acid as sole carbon and energy sources. Nitrogen-containing heterocyclic compounds were not degraded. This mutant was isolated by selecting first for oxidation of furan derivatives and then for thiophene degradation. Genetic analysis revealed that mutations in three novel genes, thdA (12 min), thdC (92 min), and thdD (98 min), were required for thiophene degradation. In addition, constitutively at both of the previously characterized fadR and atoC loci was required for efficient thiophene breakdown. The pathway of furan and thiophene degradation remains obscure, but the inability of our mutants to degrade 5-nitro- or 5-bromo-substituted furan derivatives suggests that hydroxylation at position 5 may be involved. Thiophene derivatives were toxic when they were present at concentrations of 0.1% or greater; however, addition of trace amounts of phenylalanine plus tyrosine greatly reduced this effect.

Escherichia coli↗
PubMed2003

[Genetic analysis of isozyme loci of intraspecific hybrid in Auricularia auricula].

Monokaryon strains H2 and J3 were respectively developed from the cultivated strains He-1 and Ju-1 of Auricularia auricula through protoplasted monokaryon technique. Dicaryon strain H2J3 was bred through crossbreeding of H2 and J3 as parents. Fifty-two F1 monokaryon strains were obtained from the fruitbodies of dicaryon H2J3 of A. auricula by the single-spore isolation and culture. All the tested strains, parent monokaryon strains (H2,J3) and fifty-two F1 monokaryon strains, were cultured in liquid Complete Yeast Medium(CYM) for twenty days, and the mycelia of tested strains were respectively analysed by polyacrylamide gel electrophoresis. Bian Y B et al. have reported the results of isozyme zymogram polymorphisms of cultured strains including He-1 and Ju-1, and the specific expression of esterase genes on the different stages of mycelial development in A. auricula. The same named methods of isozyme loci and alleles suggested by Gottlieb (1973) were used in this study. The relative fitness of allele segregation and theoretical expected ratio was examined by the contingency chi 2 test. The linkage relationship was assessed according to the method suggested by Rudin and Ekberg (1978). The isozyme analysis of tested strains showed that the isozymes of esterase (EST), malate dehydrogenase(MDH) and formate dehydrogenase(FDH) of A. auricula were respectively controlled by 7, 5 and 4 polymorphic loci. The isozyme bands which were controlled by EST-3, EST-4, MDH-3 and MDH-4 loci were stably expressed in the parental strains and most tested F1 monokaryon strains. Genetic analysis was impossible for these four loci. The relative fitness between allele observed value and theoretical expected value was further examined by means of contingency chi 2 at 1% level, the result indicated that significant difference existed from the chi 2 value of MDH-5 and FDH-1 in 7 polymorphic loci of EST, MDH and FDH, and denied the hypothesis in which the isozyme bands controlled by MDH-5 and FDH-1 loci were presumed to be allozyme bands. The allele observed values (100:SA) of EST-7, MDH-1, MDH-5, FDH-1, FDH-2 and FDH-4 were significant deviation of theoretical expected ratio (1:1), which showed that these variations were not due to the allele expressions. The significant difference was not be showed at the 5% level from the chi 2 values of EST-1, EST-2, EST-5, EST-6 and MDH-2, this result indicated the allele segregation was corresponding to the theoretical expected ratio at these 5 loci, these 5 loci were allozyme loci which was corresponding to Mendel's law of segregation. A total of 10 possible pair combinations from the 5 allozyme loci were tested. The numbers of monokaryon strains with parental type zymogram or recombinant type zymogram were counted up, and the chi 2I, chi 2II and chi 2L were calculated for examining the linkage relationships of these allozyme loci, the chi 2L value attained to significant difference at 1% level between EST-5 and EST-6 loci, it indicated that the linkage relationship existed between the two loci, non-linkage relationships existed between the other pairing loci of 5 allozyme loci.

Alleles↗
PubMed1981

Genetic analysis of the larval secretion gene Sgs-4 and its regulatory chromosome sites in Drosophila melanogaster.

Larval salivary gland secretion from seven wild-type stocks of Drosophila melanogaster was electrophoretically analyzed. Considerable variability occurs in the X-chromosomally coded secretion protein 4, both qualitatively, as expressed by differences in electrophoretic mobilities, and quantitatively as seen by its relative amount in the secretion. Drosophila stocks with "normal" amounts of protein 4 show approximately 80-90% dosage compensation in the males, whereas in two stocks with lower amounts of protein 4 there is no indication of dosage compensation. Genetic analysis showed that the properties of secretion protein 4 and the level of expression of the Sgs-4 gene are controlled by the X-chromosome. Recombination experiments indicate that the stock-specific characteristics of protein 4 are properties of the structural gene Sgs-4 itself or of a chromosome region immediately adjacent to Sgs-4. One recombinant (R+79), manifesting an intermediate level of dosage compensation, indicates that a chromosome segment closely distal to Sg-4 is responsible for the regulation of the gene and for dosage compensation in particular. Accordingly, Sgs-4 must be transcribed from distal to proximal. Its position on the genetic map is 3.6. Two stocks, Hikone-R and Kochi-R, which were originally described as 0-mutants produce very low amounts of a specific secretion protein, 4 h, as revealed by a transvection effect and also by fluorography of overloaded gels.

Animals↗
PubMed1993

Toward a molecular genetic analysis of spermatogenesis in Drosophila melanogaster: characterization of male-sterile mutants generated by single P element mutagenesis.

We describe 83 recessive autosomal male-sterile mutations, generated by single P element mutagenesis in Drosophila melanogaster. Each mutation has been localized to a lettered subdivision of the polytene map. Reversion analyses, as well as complementation tests using available chromosomal deficiencies, indicate that the insertions are responsible for the mutant phenotypes. These mutations represent 63 complementation groups, 58 of which are required for spermatogenesis. Phenotypes of the spermatogenesis mutants were analyzed by light microscopy. Mutations in 12 loci affect germline proliferation, spermatocyte growth, or meiosis. Mutations in 46 other loci disrupt differentiation and maturation of spermatids into motile sperm. This collection of male-sterile mutants provides the basis for a molecular genetic analysis of spermatogenesis.

Animals↗
PubMed2006

A novel missense mutation in Van der Woude syndrome: usefulness of fingernail DNA for genetic analysis.

Van der Woude syndrome (VWS) is an autosomal-dominant oral facial disorder. To find a gene mutation in a Japanese family using fingernail DNA samples, we performed this study. We hypothesized that a gene mutation in IRF6 might be involved in VWS, and that fingernail DNA samples may be valuable for detecting such mutations. Linkage and haplotype analyses of the family mapped the disease locus to the 1q32-q41 region. Mutation analysis with an improved extraction method for fingernail DNA detected a novel missense mutation (1046A>T, E349V) in exon 7 of IRF6 in all the affected members of the family. Since the E349V change may disturb the hydrophobic core and affect regulatory activity of IRF6, it is most likely that the mutation is causative for VWS in this family. Fingernail DNA is thus useful for linkage and mutation analyses, since the fingernail can be easily obtained non-invasively, sent through the mail, and stored for a long period. We emphasize here the usefulness of fingernail DNA for the genetic analysis of a disease.

Adenine↗
PubMed2005

Genetic analysis and molecular mapping of a pale flower allele at the W4 locus in soybean.

In soybean (Glycine max (L.) Merr.), the w4-mutable line that harbors the w4-m allele was identified in 1983. It was proposed that this line contained an autonomous transposable element at the W4 locus, which is a major locus controlling the biosynthesis of anthocyanin. The w4-m allele can revert to the W4 allele that produces the wild-type phenotype, or sometimes to other alleles that produce intermediate phenotypes. Mutant plants that produce pale flowers were identified among the progeny of a single germinal revertant event from the w4-mutable line. Through genetic analysis, we established that the pale-flower mutation was conditioned by a new allele (w4-p) at the W4 locus. The w4-p allele is dominant to the w4 allele but recessive to the W4 allele, and the w1 allele has an epistatic effect on the w4-p allele. The pale-mutant line (w4-pw4-p) was designated as Genetic Type Collection number T369. An F2 mapping population derived from the cross of Minsoy (W4W4) x T369 (w4-pw4-p) was used to map the W4/w4-p locus, using simple sequence repeat (SSR) markers. The W4 locus was located at one end of molecular linkage group D2, 2.3 cM from the SSR marker Satt386 and close to the nearby telomere.

Alleles↗
PubMed1995

[Genetic analysis of differences in metabolism of juvenile hormone in lines of Drosophila virilis resistant and sensitive to heat stress].

The metabolism of juvenile hormone (JH) in imagos of two Drosophila species (D. virilis and D. melanogaster) was studied in the normal state and after short-term heat stress. Females of both species respond to stress by a decrease in the activity of JH esterase. This decrease is realized through a decrease in the amount of protein. JH metabolism in males does not change after heat stress. Genetic analysis of differences in the activity of DPF-resistant JH esterase in stress-sensitive and stress-resistant strains of D. virilis was performed. The differences are controlled by one autosomal gene.

Animals↗
PubMed2000

Genetic analysis of the Drosophila 63F early puff. Characterization of mutations in E63-1 and maggie, a putative Tom22.

The 63F early puff in the larval salivary gland polytene chromosomes contains the divergently transcribed E63-1 and E63-2 ecdysone-inducible genes. E63-1 encodes a member of the EF-hand family of Ca(2+)-binding proteins, while E63-2 has no apparent open reading frame. To understand the functions of the E63 genes, we have determined the temporal and spatial patterns of E63-1 protein expression, as well as undertaken a genetic analysis of the 63F puff. We show that E63-1 is expressed in many embryonic and larval tissues, but the third-instar larval salivary gland is the only tissue where increases in protein levels correlate with increases in ecdysone titer. Furthermore, the subcellular distribution of E63-1 protein changes dynamically in the salivary glands at the onset of metamorphosis. E63-1 and E63-2 null mutations, however, have no effect on development or fertility. We have characterized 40 kb of the 63F region, defined as the interval between Ubi-p and E63-2, and have identified three lethal complementation groups that correspond to the dSc-2, ida, and mge genes. We show that mge mutations lead to first-instar larval lethality and that Mge protein is similar to the Tom22 mitochondrial import proteins of fungi, suggesting that it has a role in mitochondrial function.

Amino Acid Sequence↗
PubMed1992

Genetic analysis of ubiquitin-dependent protein degradation.

Selective degradation of cellular proteins serves to eliminate abnormal proteins and to mediate the turnover of certain short-lived proteins, many of which have regulatory functions. In eukaryotes a major pathway for selective protein degradation is ATP-dependent and is mediated by the ubiquitin system. This pathway involves substrate recognition by components of a ubiquitin-protein ligase system, covalent attachment of ubiquitin moieties to proteolytic substrates, and subsequent degradation of these conjugates by a multicatalytic protease complex. Recent genetic evidence suggests that the remarkable selectivity of this process is largely controlled at the level of substrate recognition by the ubiquitin ligase system. In Saccharomyces cerevisiae, ubiquitin-conjugating enzymes UBC1, UBC4 and UBC5 have been identified as key components of this highly conserved degradation pathway. Genetic analysis indicates that ubiquitin-dependent proteolysis is essential for cell viability and that UBC4 and UBC5 enzymes are essential components of the eukaryotic stress response.

Fungal Proteins↗
PubMed1998

Genetic analysis of resistance to fenpropimorph in Aspergillus niger.

Resistance to the morpholine-fungicide fenpropimorph was studied in Aspergillus niger and A. nidulans. Mass selection of conidia of A. nidulans on agar amended with the fungicide at different concentrations did not yield of resistant mutants, even after UV-treatment of the conidia. In contrast, similar experiments with A. niger generated many fenpropimorph-resistant mutants. The mutants displayed cross-resistance to fenpropidin and generally showed wild-type sensitivity to the unrelated toxicants fenarimol and cycloheximide. Genetic analysis of fenpropimorph resistance in A. niger was carried out by means of the parasexual cycle. In the mutants tested, two genes located on linkage group II were involved in fenpropimorph resistance. Dominance tests showed that resistance to fenpropimorph in A. niger is recessive.

Aspergillus niger↗
PubMedDate not supplied

Parallel molecular genetic analysis.

We describe recent progress in parallel molecular genetic analyses using DNA microarrays, gel-based systems, and capillary electrophoresis and utilization of these approaches in a variety of molecular biology assays. These applications include use of polymorphic markers for mapping of genes and disease-associated loci and carrier detection for genetic diseases. Application of these technologies in molecular diagnostics as well as fluorescent technologies in DNA analysis using immobilized oligonucleotide arrays on silicon or glass microchips are discussed. The array-based assays include sequencing by hybridization, cDNA expression profiling, comparative genome hybridization and genetic linkage analysis. Developments in non microarray-based, parallel analyses of mutations and gene expression profiles are reviewed. The promise of and recent progress in capillary array electrophoresis for parallel DNA sequence analysis and genotyping is summarized. Finally, a framework for decision making in selecting available technology options for specific molecular genetic analyses is presented.

DNA↗
PubMed1996

Genetic analysis of synchronous mucinous tumors of the ovary and appendix.

The coexistence of mucinous ovarian and appendiceal tumors in association with pseudomyxoma peritonei (PP) is well established. However, it has not been determined whether they represent independent or metastatic neoplasms. The authors analyzed microsatellites on chromosome 17q 21.3-22 (nm23), 3p 25-26 (von Hippel Lindau disease [VHL] gene), and 5q 21-22 (D5S346 locus) in 12 synchronous ovarian and appendiceal mucinous lesions. Loss of heterozygosity (LOH) at the nm23 locus has been shown previously in ovarian carcinomas, and genetic alterations at both the 3p and 5q loci have been reported in colorectal carcinomas. The ovarian lesions consisted of nine mucinous tumors of low malignant potential and three invasive adenocarcinomas, and the appendiceal lesions consisted of eight carcinomas without invasion, two invasive carcinomas, and two mucosal hyperplasias. DNA was extracted from microdissected cells obtained from formalin-fixed, paraffin-embedded tissue sections and amplified by polymerase chain reaction. In three specimens, genetic alterations occurred at 17q 21.3-22 in only the ovarian tumors. One of these cases showed LOH on chromosome 5q 21-22 in only the appendiceal tumor. In three other specimens, LOH at the same locus was found in both tumors. Six specimens did not show LOH at any locus. These results suggest that a subset of synchronous mucinos ovarian and appendiceal lesions showing different LOH patterns in both sites most likely represent patients with two separate primary lesions. Another group of specimens with the same allelic loss in both tumors most likely represent patients with a single primary and metastatic spread. Thus, genetic analysis of these lesions may be useful in investigating the origin of histologically similar synchronous tumors.

Adenocarcinoma, Mucinous↗
PubMed2003

Bronchiolar columnar cell dysplasia--genetic analysis of a novel preneoplastic lesion of peripheral lung.

Atypical adenomatous hyperplasia is the only known precursor lesion of lung adenocarcinomas (ACs) so far. Here, we describe a new dysplastic lesion in the bronchioles of peripheral lung for which we propose the name bronchiolar columnar cell dysplasia (BCCD). Eight of fourteen BCCDs were successfully analyzed by means of comparative genomic hybridization (CGH). The average number of chromosomal aberrations was 2.6 in BCCD and 14.7 in concomitant AC. Among the aberrations were losses of 3p, 9, 13, 14 and gains of 1q, 17, 19q and 20q. Summarizing our data from morphological and genetic analysis, we conclude that BCCD is a preneoplasia of the bronchiolar epithelium and most probably represents an additional precursor lesion of lung adenocarcinomas.

Adenocarcinoma↗
PubMed1995

[A genetic analysis of mutant chromosomes 3 with a similar spectrum of phenotypic action from geographically distant populations of Drosophila melanogaster].

From geographically distant populations of Drosophila melanogaster, the following mutant phenotypes with a wide spectrum of similar phenotypic variation were isolated: #89300 and #89386 from a population of Uman' (Ukraine) in 1989, and #920017, #921314, and #921503 from a population of Gorno-Altaisk (Altai) in 1992. A similar mutant phenotype (line #i13) was obtained by gamma-irradiation of the laboratory line Canton S. Phenotypic changes involve eye shape and structure, morphology of body appendages (wings, legs, and antennae), and fertility. Genetic analysis of mutations #89300 and #89386 showed that they belong to the third linkage group. Chromosomes 3 of mutants #89300 and #89386 carry inversions In(3R)92D-98F and In(3R)89F-95A, respectively. A complementation test for allelism of the isolated mutations among themselves and with several laboratory lines was conducted. The mutant phenotypical effect of the chromosomes isolated is assumed to be related to geographic variants of alleles of two closely linked genes, rotund and roughened eye and claret.

Alleles↗
PubMed1986

Fine structure genetic analysis of a beta-globin promoter.

A novel procedure for saturation mutagenesis of cloned DNA was used to obtain more than 100 single base substitutions within the promoter of the mouse beta-major globin gene. The effects of these promoter substitutions on transcription were determined by transfecting the cloned mutant genes into HeLa cells on plasmids containing an SV40 transcription enhancer, and measuring the levels of correctly initiated beta-globin transcripts after 2 days. Mutations in three regions of the promoter resulted in a significant decrease in the level of transcription: (i) the CACCC box, located between -87 and -95, (ii) the CCAAT box, located between -72 and -77, and (iii) the TATA box, located between -26 and -30 relative to the start site of transcription. In contrast, two different mutations in nucleotides immediately upstream from the CCAAT box resulted in a 3- to 3.5-fold increase in transcription. With two minor exceptions, single base substitutions in all other regions of the promoter had no effect on transcription. These results precisely delineate the cis-acting sequences required for accurate and efficient initiation of beta-globin transcription, and they establish a general approach for the fine structure genetic analysis of eukaryotic regulatory sequences.

Animals↗
PubMed1999

Multiple endocrine neoplasia type 1: atypical presentation, clinical course, and genetic analysis of multiple tumors.

Multiple endocrine neoplasia type 1 (MEN1) is characterized by the development of endocrine tumors of the parathyroid and pituitary glands, pancreas, and duodenum. Less frequently occurring tumors associated with MEN1 include non-endocrine tumors such as lipomas and angiofibromas. An increased incidence of thyroid neoplasms, leiomyomas, adrenal cortical hyperplasia, hepatic focal nodular hyperplasia, and renal angiomyolipoma has been noted in the MEN1 population. The pathogenesis of non-neuroendocrine tumors in MEN1 is unknown. We report a complex clinical course and a detailed morphologic and genetic analysis of a series of tumors that developed in a patient with MEN1. All tumors were microdissected and analyzed for loss of heterozygosity of the MEN1 gene. A germline mutation of the MEN1 gene was detected, and deletions of the MEN1 gene were consistently detected in multiple neuroendocrine tumors involving the parathyroid glands and the pancreas and a hepatic neuroendocrine tumor metastasis, as predicted by Knudson's "two hit" hypothesis. Two hits of the MEN1 gene were also detected in esophageal leiomyoma tissue, suggesting that tumorigenesis was directly related to the patient's underlying MEN1. In contrast, follicular thyroid adenoma, papillary thyroid carcinoma, hepatic focal nodular hyperplasia, and adrenal cortical hyperplasia consistently showed retained heterozygosity of the MEN1 gene with flanking markers and an intragenic marker. Therefore, these tumors appear to develop along pathogenetic pathways that are different from classical MEN1-associated tumors.

Adult↗
PubMed1996

Genetic analysis reveals cell type-specific regulation of receptor tyrosine kinase c-Kit by the protein tyrosine phosphatase SHP1.

Receptor protein tyrosine kinases (RTKs) transmit downstream signals via interactions with secondary signaling molecules containing SH2 domains. Although many SH2-phosphotyrosyl interactions have been defined in vitro, little is known about the physiological significance of specific RTK/SH2 interactions in vivo. Also, little is known about the mechanisms by which specific RTKs interact with and/or are regulated by specific protein tyrosine phosphatases (PTPs). To address such issue, we carried out a genetic analysis of the previously reported biochemical interaction between the RTK c-Kit, encoded at the W locus, and the SH2-containing non-transmembrane PTP SHP1, encoded at the motheaten (me) locus (1). Mice carrying a kinase-defective allele of c-Kit (Wv/+) were crossed with me/+ mice, which carry one effectively null allele of SHP1, and then backcrossed to generate all possible allelic combinations. Our results indicate strong intergenic complementation between these loci in hematopoietic progenitor cells. Compared to progenitors purified from normal mice, bone marrow progenitor cells (lin-) from me/me mice markedly hyper-proliferated in response to Kit ligand (KL). stimulation. Superimposition of the me/me genotype increased the number of one marrow-derived CFU-E from Wv/+ mice. Conversely, the presence of one or two copies of Wv decreased the number of macrophages and granulocytes in me/me lung, skin, peripheral blood and bone marrow, thereby decreasing the severity of the me/me phenotype. The decrease in dermal mast cells in Wv/Wv mice was rescued to levels found in Wv/+mice by superimposition of the me/me genotype. Surprisingly, however, the presence or absence of SHP1 had no effect on the proliferative response of bone marrow-derived cultured mast cells to KL or IL3 ex vivo. Nevertheless, the immediate-early response to KL stimulation, as measured by KL-induced tyrosyl phosphorylation, was substantially increased in mast cells from Wv/+:me/me compared to Wv/ +:+/+ mice, strongly suggesting that SHP1 directly dephosphorylates and regulates c-Kit. Taken together, our results establish that SHP1 negatively regulates signaling from c-Kit in vivo, but in a cell type-specific manner.

Animals↗
PubMed1980

[Murine near-diploid cell clones: a model for the genetic analysis of signs of transformation].

Several near-diploid clones were obtained from the established mouse cell line, CAK-7. These clones proved to be highly oncogenic in syngeneic irradiated mice (TD50 = 1 x 10(2)--2 x 10(3). They differed in plating efficiency in semi-solid medium (from 5 x 10(-3) to 22 x 10(-5)). There was no correlation between tumorigenicity of the cells and their plating efficiency in methylcellulose. The differences between clones able to form anchorage-independent clonies would permit their use for the genetic analysis of this kind of malignancy.

Animals↗