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PubMed1993

Mapping, cloning and genetic characterization of the region containing the Wilson disease gene.

Wilson disease (WD) is an autosomal recessive disorder of copper transport which map to chromosome 13q14.3. In pursuit of the WD gene, we developed yeast artificial chromosome and cosmid contigs, and microsatellite markers which span the WD gene region. Linkage disequilibrium and haplotype analysis of 115 WD families confined the disease locus to a single marker interval. A candidate cDNA clone was mapped to this interval which, as shown in the accompanying paper, is very likely the WD gene. Our haplotype and mutation analyses predict that approximately half of all WD mutations will be rare in the American and Russian populations.

Base Sequence↗

PubMedDate not supplied

[Distribution and genetic characterization of porcine Campylobacter coli isolates].

The aim of this study was to evaluate the impact of the slaughter process on the Campylobacter (C.) coli prevalence on pig carcasses and finally pork. To detect C. spp., faecal samples, organ samples and surfaces of slaughter pigs were sampled. Additionally, various abattoir surfaces (n=208) and 227 pork and minced meat samples were included in our study. Whereas a high C. spp. prevalence (64.0%) was detectable in the faeces of slaughter pigs (all isolates were identified as C. coli), low detection rates were observed on pig carcasses after the slaughter process before the chilling period (21.1%). The impact of chilling reduced the detection rate of C spp. on pig carcasses even further to 0.8%. Only C. jejuni strains were isolated after the chilling process. Chilling and the associated drying of the skin are responsible for that massive reduction of C. spp prevalence. Significantly more C. spp. were isolated from livers compared to the corresponding carcasses. Only 5 out of 208 swab samples from different surfaces of the abattoir were C. coli positive. Bacteriological investigation could not detect any C. spp. strains from pork and minced pork meat. The low detection rates at the end of the slaughter and processing line indicate that pork may only play a minor role in the transmission of C. coli infections to humans. By genotyping C. coli-isolates from selected animals we were able to demonstrate three possible ways of contamination of the slaughter carcass surface. Genetically highly related strains were detectable on carcass surfaces of consecutively slaughtered animals. Faecal isolates and isolates from the carcass surface showed occasional high similarities. C. coli-genotypes from tonsils and genotypes from the corresponding slaughter carcasses formed a close cluster.

Abattoirs↗

PubMed1997

Functional and genetic characterization of mcpC, which encodes a third methyl-accepting chemotaxis protein in Bacillus subtilis.

A 3135 bp DNA segment downstream of the spl gene on the Bacillus subtilis chromosome was cloned and its nucleotide sequence determined. An open reading frame capable of encoding a putative protein of 654 amino acids with a calculated molecular mass of 72.1 kDa was identified. The deduced amino acid sequence was similar to the McpA and McpB proteins of B. subtilis. McpA and McpB encode different methyl-accepting chemotaxis proteins (MCPs). A mutant strain containing an antibiotic resistance DNA cassette inserted into the region containing the MCP-like reading frame suffered a complete loss of taxis to the amino acids cysteine, proline, threonine, glycine, serine, lysine, valine and arginine. The open reading frame was designated mcpC. The wild-type and an mcpC mutant strain were analysed for their content of methylated proteins and it was found that mcpC encodes a methylated membrane protein that has previously been designated H3. These results show that mcpC encodes a third MCP in B. subtilis. The transcription start site upstream of the mcpC gene was determined by primer extension analysis and it was found to be preceded by a potential promoter sequence that is recognized by the sigma D form of RNA polymerase. The level of beta-galactosidase expressed from a transcriptional mcpC-lacZ fusion was increased threefold when cells entered the stationary phase. No beta-galactosidase could be detected in a sigD genetic background.

Amino Acid Sequence↗

PubMed1982

Biochemical and genetic characterization of the Lowell variant. A new phenotype of 6-phosphogluconate dehydrogenase.

A new electrophoretic variant of 6-phosphogluconate dehydrogenase (6PGD) has been detected in the Caucasian population in North Carolina, and family studies have shown this variant to be transmissible. This variant has been given the trivial name "Lowell" and the allele controlling its synthesis in conjunction with 6PGDA has been named 6PGDL. The banding pattern produced by the Lowell variant after electrophoresis is not affected by either NADP or 2-mercaptoethanol. Inhibition studies with urea and iodoacetate have shown that this variant is inhibited to approximately the same degree as the Richmond and Friendship variants. Thermostability studies have shown that the isozyme bands encoded by 6PGDA, 6PGDElcho, 6PGDC, and 6PGDL have a relative thermal stability in the order 6PGDA greater than 6PGDElcho greater than 6PGDC greater than 6PGDL.

Electrophoresis, Starch Gel↗

PubMed1989

Carotenoid biosynthesis in photosynthetic bacteria. Genetic characterization of the Rhodobacter capsulatus CrtI protein.

Carotenoids are photoprotective pigments present in many photosynthetic and nonphotosynthetic organisms. The desaturation of phytoene into phytofluene is an early step in the biosynthetic pathway that in the photosynthetic bacterium Rhodobacter capsulatus is mediated by the product of the crtI gene. Here we report the sequence of this gene and the identification of CrtI as a membrane protein of approximate Mr 60,000. Mutant strains with 5-fold lower or 10-fold higher levels of CrtI with respect to wild type have only small differences in their carotenoid content, indicating that the cellular concentration of CrtI is not a limiting factor in carotenoid biosynthesis. However, a correlation was found between the levels of CrtI and the formation of a photosynthetic antenna system.

Amino Acid Sequence↗

PubMed2006

Genetic characterization of Trypanosoma evansi isolated from a patient in India.

The first human case of trypanosomiasis caused by Trypanosoma evansi was recently discovered in India. We have focused on the parasite to investigate whether this atypical infection was due to a particular genotype of T. evansi. The SRA gene was not detected by PCR in the Indian human T. evansi (TEVH) DNA sample. TEVH appears to be closely related to Vietnam WH, with identical alleles for TRBPA and MT30-33 AC/TC microsatellites. Furthermore, T. evansi has homogeneous kDNA minicircles and the minicircles of isolate TEVH were shown to be of Type A. Thus, the T. evansi isolated from an Indian patient appears to be a typical T. evansi as far as we can judge, suggesting that the explanation for this unusual infection may lie with the patient.

Animals↗

PubMed1980

Biochemical and genetic characterization of nirB mutants of Escherichia coli K 12 pleiotropically defective in nitrite and sulphite reduction.

Mutants of Escherichia coli K12 defective in the nirB gene lack NADH-dependent nitrite reductase activity and reduce nitrite slowly during anaerobic growth. With one exception these mutants require cysteine for growth. Cytochrome C552 synthesis and the assimilation of ammonia are unaffected by the nirB mutation. The defective gene is located between the crp and aroB genes at minute 73 on the E. coli chromosome. Mapping and reversion studies indicate the nirB is identical to the previously described cysG gene. It is suggested that the product of the cysG+ (nirB+)¿gene is an enzyme required for the synthesis of sirohaem, a prosthetic group of enzymes which catalyse the six-electron reduction of nitrite to ammonia and sulphite to sulphide.

Chromosome Mapping↗

PubMed2002

Genetic characterization of Drosophila Mi-2 ATPase.

Mammalian Mi-2, an auto-antigen for dermatomyositis, is known to be an adenosine triphosphate (ATP)-dependent nucleosome remodelling factor. The Drosophila homologue of Mi-2 (dMi-2) gene is located at 76D5-6 on the left arm of the third chromosome and is transcribed into two alternate transcripts (dMi-2a and dMi-2b). Both transcripts are present at high levels in the ovary and during the first 8 h of embryogenesis when detected by Northern blot analysis. The localization of protein was nuclear, which is consistent with its proposed function as a component of the chromatin remodelling complex. Several lines of recessive mutants including mutations in dMi-2 were isolated and classified into four different complementation groups. Four alleles of dMi-2 mutants were further characterized in molecular nature; dMi-2(BL1) was found to have a mutation in the ATP-binding motif of the ATPase domain, dMi-2(BL7) in the core histidine of the first plant homeodomain zinc finger and dMi-2(BL12) in a conserved serine in the chromodomain. On the other hand, dMi-2(BL3) did not have any change in the coding region. The expression pattern of dMi-2 and the embryonic lethal phenotypes of mutants indicate that dMi-2 is essential for embryonic development in Drosophila melanagaster.

Adenosine Triphosphatases↗

PubMed2005

Genetic characterization and molecular mapping of a Hessian fly-resistance gene transferred from T. turgidum ssp. dicoccum to common wheat.

A gene (temporarily designated Hdic) conferring resistance to the Hessian fly (Hf) [Mayetiola destructor (Say)] was previously identified from an accession of German cultivated emmer wheat [Triticum turgidum ssp. dicoccum (Schrank ex Schübler) Thell] PI 94641, and was transferred to the Hf-resistant wheat germplasm KS99WGRC42. The inheritance of Hdic resistance exhibited incomplete penetrance because phenotypes of some heterozygous progenies are fully resistant and the others are fully susceptible. Five simple sequence repeat (SSR) markers (Xgwm136,Xcfa2153, Xpsp2999,Xgwm33, and Xbarc263) were linked to the Hdic gene on the short arm of wheat chromosome 1A in the same region as the H9, H10, and H11 loci. Flanking markers Xgwm33 and Xcfa2153 were mapped at distances 0.6 cM proximal and 1.4 cM distal, respectively. Marker analysis revealed that a very small intercalary chromosomal segment containing Hdic was transferred from emmer wheat to KS99WGRC42. This is the first emmer-derived Hf-resistance gene that has been mapped and characterized. The Hdic gene confers a high level of antibiosis to biotypes GP and L, as well as to strains vH9 and vH13 of the Hf, which is different from the biotype reaction patterns of the known Hf-resistance genes on chromosome 1A (H5 and H11 susceptible to biotype L, H9 and H10 susceptible to strain vH9). These results suggested that Hdic is either a new gene or a novel allele of a known H gene on chromosome 1A. The broad spectrum of resistance conferred by the Hdic gene makes it valuable for developing Hf resistant wheat cultivars.

Animals↗

PubMed1983

Genetic characterization of a gene for prolipoprotein signal peptidase in Escherichia coli.

A mutation (lspA, prolipoprotein signal peptidase) rendering the prolipoprotein signal peptidase temperature-sensitive in Escherichia coli has been analyzed. The mutation was mapped in the dnaJ-rpsT-ileS-dapB region by interrupted mating with various Hfr strains and P1 phage transduction. lambda transducing phage lambda ddapB2 that carries the rpsT-ileS-dapB region was shown to complement the lspA mutation. Plasmid pLC3-13 which had been isolated from Clarke and Carbon's collection as a plasmid carrying the lspA locus was shown to carry the dnaJ and rpsT loci. Complementation analysis with plasmids carrying various DNA fragments derived from pLC3-13 showed that the lspA locus is between the rpsT and ileS loci. The wildtype allele was dominant over the lspA allele.

Bacteriophage lambda↗

PubMed1989

Genetic characterization of frameshift suppressors with new decoding properties.

Suppressor mutants that cause ribosomes to shift reading frame at specific and new sequences are described. Suppressors for trpE91, the only known suppressible -1 frameshift mutant, have been isolated in Escherichia coli and in Salmonella typhimurium. E. coli hopR acts on trpE91 within the 9-base-pair sequence GGA GUG UGA, is dominant, and is located at min 52 on the chromosome. Its Salmonella homolog maps at an equivalent position and arises as a rarer class in that organism as compared with E. coli. The Salmonella suppressor, hopE, believed to be in a duplicate copy of the same gene, maps at min 17. The +1 suppressor, sufT, acts at the nonmonotonous sequence CCGU, is dominant, and maps at min 59 on the Salmonella chromosome.

Base Sequence↗

PubMed2006

Isolation and genetic characterization of new reassortant H3N1 swine influenza virus from pigs in the midwestern United States.

Since the introduction of H3N2 swine influenza viruses (SIVs) into U.S. swine in 1998, H1N2 and H1N1 reassortant viruses have emerged from reassortment between classical H1N1 and H3N2 viruses. In 2004, a new reassortant H3N1 virus (A/Swine/Minnesota/00395/2004) was identified from coughing pigs. Phylogenetic analyses revealed a hemagglutinin segment similar to those of contemporary cluster III H3N2 SIVs and a neuraminidase sequence of contemporary H1N1 origin. The internal genes were of swine, human, and avian influenza virus origin, similar to those of contemporary U.S. cluster III H3N2 SIVs. The recovery of H3N1 is further evidence of reassortment among SIVs and justifies continuous surveillance.

Animals↗

PubMed1976

Biochemical and genetic characterization of a carbamyl phosphate synthetase mutant of Escherichia coli K12.

An unusual Escherichia coli K12 mutant for carbamyl phosphate synthetase is described. The mutation was generated by bacteriophage MUI insertion and left a 5% residual activity of the enzyme using either ammonia or glutamine as donors. The mutation is recessive to the wild-type allele and maps at or near the pyrA gene, but the mutant requires only arginine and not uracil for growth. By a second block in the pyrB gene it was possible to shift the accumulated carbamyl phosphate to arginine biosynthesis. The Km values and the levels of ornithine activation and inhibition by UMP were normal in the mutant enzyme.

Ammonia↗

PubMed2002

Genetic characterization of growth hormone deficiency and resistance: implications for treatment with recombinant growth hormone.

Growth failure can be caused by deficient growth hormone production or action. The genes involved in pituitary development, somatotrope function, as well as growth hormone synthesis, secretion, and action have recently been characterized in considerable detail. Familial growth failure has played an important role in identifying these genes, and a large number of mutations adversely affecting the development and function of the growth hormone/insulin-like growth factor axis have been discovered. Inactivating mutations leading to growth retardation in humans have been identified in several pituitary transcription factor genes (HESX1, PITX2, LHX3, PROP1, POU1F1) as well as in genes encoding the growth hormone-releasing hormone receptor (GHRH-R), the G(s) protein alpha subunit (GNAS1), growth hormone itself (GH-1), the growth hormone receptor (GHR), and in a single case each, the insulin-like growth factor I (IGF-I) and the IGF-I receptor. Mutations in pituitary transcription factors cause developmental abnormalities of the pituitary and deficiency of multiple pituitary hormones [growth hormone (GH), prolactin (Prl), thyrotropin (TSH) and lutropin/follitropin (LH/FSH)]. Most of the syndromes respond well to therapy with recombinant GH; exceptions are antibody-mediated resistance in GHD type IA (not all patients) and cases of Laron syndrome (GHR deficiency). Such patients respond to IGF-I therapy. This review summarizes the molecular genetics, functional defects, phenotypes, diagnostic considerations and therapeutic aspects of syndromes associated with mutations in the relevant genes.

Animals↗

PubMed1989

Genetic characterization of the pnuC gene, which encodes a component of the nicotinamide mononucleotide transport system in Salmonella typhimurium.

The pnuC gene, which encodes a component of the nicotinamide mononucleotide transport system, has been mapped and oriented. The gene order of the pnuC region, which is at min 17 of the Salmonella chromosome, is nadA-pnuC-aroG-gal. Polarity tests, with pnuC::Mu d-lac operon fusions, reveal that the pnuC gene is the promoter distal gene in an operon with the nadA gene, which encodes the second enzyme of the pyridine biosynthetic pathway. The nadA pnuC operon is regulated by the NadI repressor. The pnuC gene also has its own promoter, since strains with a nadA::Tn10d(Tc) insertion still express the pnuC gene at a low, unregulated level.

Bacterial Proteins↗

PubMed1989

Clinical and genetic characterization of nonclassic 21-hydroxylase deficiency.

Nonclassic steroid 21-hydroxylase deficiency is a frequent, relatively mild disorder of cortisol biosynthesis characterized by variable signs of postnatal androgen excess. It is inherited as an allelic variant of the CYP21B gene encoding the 21-hydroxylase enzyme. CYP21B is located in the HLA histocompatibility complex, and a nonclassic allele is often associated with characteristic HLA antigens: B14;DR1. A CYP21B gene from a HLA-B14;DR1 homozygous patient with nonclassic 21-hydroxylase deficiency was cloned and analyzed. Five deviations from the normal sequence of CYP21B were found, but only one appeared likely to affect the functional integrity of the protein: codon 281, GTG, encoding valine, was changed to TTG, leucine. An oligonucleotide probe was constructed corresponding to the mutant sequence surrounding codon 281 and hybridized with DNA samples digested with restriction endonuclease Taq I. Samples from 8 nonclassic 21-hydroxylase deficiency patients carrying HLA-B14;DR1 contained a hybridizing fragment 3700 base-pairs long, indicating presence of the val-281 mutation in the CYP21B gene. In contrast, unaffected individuals and one patient who lacked HLA-B14;DR1 showed no evidence of the val-281 mutation in CYP21B. We conclude that the codon 281 mutation is a consistent molecular genetic marker for nonclassic 21-hydroxylase deficiency associated with HLA-B14;DR1.

Adrenal Hyperplasia, Congenital↗

PubMed2004

Toxoplasma gondii infections in cats from Paraná, Brazil: seroprevalence, tissue distribution, and biologic and genetic characterization of isolates.

Cats are important in the epidemiology of Toxoplasma gondii because they are the only hosts that can excrete environmentally resistant oocysts. The prevalence of T. gondii was determined in 58 domestic cats from 51 homes from Santa Isabel do Ivai, Parana State, Brazil where a water-associated outbreak of acute toxoplasmosis had occurred in humans. Antibodies to T. gondii were found with the modified agglutination test in 49 of 58 (84.4%) cats at a serum dilution of 1:20. Tissues (brain, heart, and skeletal muscle) of 54 of these cats were bioassayed in T. gondii-free, laboratory-reared cats; T. gondii oocysts were excreted by 33 cats that were fed feline tissues. Brains from these 54 cats were bioassayed in mice; T. gondii was isolated from 7. Skeletal muscles and hearts of 15 cats were also bioassayed in mice; T. gondii was isolated from skeletal muscles of 9 and hearts of 13. The results indicate that T. gondii localizes in muscle tissue more than the brains of cats. In total there were 37 T. gondii isolates from 54 cats. Most isolates of T. gondii were virulent for mice. Genotyping of the 37 isolates of T. gondii, using the SAG2 locus, revealed that 15 isolates were type I and 22 were type III. The absence of type II genotype in cats in this study is consistent with the previous studies on T. gondii isolates from Brazil and is noteworthy because most T. gondii isolates from the United States are type II. These findings support the view that Brazilian and North American T. gondii isolates are genetically distinct. This is the first report of genotyping of T. gondii isolates from the domestic cat.

Agglutination Tests↗

PubMed1984

Morphological and genetic characterization of a bacteriophage-resistant Bacillus subtilis macrofiber-producing strain.

Bacillus subtilis C6 phi R4 is an SPO1-resistant derivative of strain C6D, a left-hand macrofiber-producing strain described previously (N. H. Mendelson, Proc. Natl. Acad. Sci. U.S.A. 75:2478-2482, 1978). In addition to the phage resistance property, strain C6 phi R4 differs from its parent in macrofiber organization and formation of aggregates in liquid shake cultures. The phage resistance mutation was located in the gtaC gene. The macrofiber organization and aggregation phenotypes also appear to be controlled by the gtaC locus. Strains constructed by introduction of the gtaC mutation into C6D appear to be identical to the original C6 phi R4 strain in all phenotypic properties. In contrast, other constructs carrying either gtaA or gtaB that are resistant to SPO1 do not display the characteristic C6 phi R4 morphological phenotypes.

Bacillus subtilis↗