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Biomedical subjects

A M Ryan

Publications and source records attributed to A M Ryan.

At least 55 records · Page 3Linked to original sources
PubMed1993

Somatic cell mapping of conglutinin (CGN1) to cattle syntenic group U29 and fluorescence in situ localization to Chromosome 28.

A 260-bp genomic PstI fragment, which encodes a portion of the carbohydrate recognition domain, was used along with hybrid somatic cells to map the conglutinin gene (CGN1) to domestic cow (Bos taurus) syntenic group U29. In turn, a cosmid containing the entire bovine CGN1 was used with fluorescence in situ hybridization to sublocalize this gene to cattle Chromosome (Chr) (BTA) 28 band 18. Since BTA 28 and several of the other small acrocentric autosomes of cattle are difficult to discriminate, we have also chromosomally sublocalized CGN1 to the p arm of the lone biarmed autosome of the gaur (Bos gaurus). The use of the gaur 2/28 Robertsonian as a marker chromosome and our assignment of CGN1 to BTA 28 should help resolve some of the nomenclatural questions involving this cattle chromosome.

Animals↗
PubMed1993

Physical mapping of the lysozyme gene family in cattle.

Amplification of an ancestral lysozyme gene in artiodactyls is associated with the evolution of foregut fermentation in the ruminant lineage and has resulted in about ten lysozyme genes in true ruminants. Hybridization of a cow stomach lysozyme 2 cDNA clone to restricted DNAs of a panel of cow x hamster hybrid cell lines revealed that all but one of the multiple bovine-specific bands segregate concordantly with the marker for bovine syntenic group U3 [Chromosome (Chr) 5]. The anomalous band was subsequently mapped to bovine syntenic group U22 (Chr 7) with a second panel of hybrids representing all 31 bovine syntenic groups. By two-dimensional pulsed-field gel electrophoresis the lysozyme genes on cattle Chr 5 were shown to be clustered on a 2- to 3-Mb DNA fragment, while the lactalbumin gene and pseudogenes that are paralogous and syntenic with the lysozymes were outside the lysozyme gene cluster. Chromosomal fluorescence in situ hybridization of a cocktail of lysozyme genomic clones localized the lysozyme gene cluster to cattle Chr 5 band 23, corroborating the somatic cell assignment.

Animals↗
PubMed1993

Chromosomal localization of uroplakin genes of cattle and mice.

The asymmetric unit membrane (AUM) of the apical surface of mammalian urinary bladder epithelium contains several major integral membrane proteins, including uroplakins IA and IB (both 27 kDa), II (15 kDa), and III (47 kDa). These proteins are synthesized only in terminally differentiated bladder epithelial cells. They are encoded by separate genes and, except for uroplakins IA and IB, appear to be unrelated in their amino acid sequences. The genes encoding these uroplakins were mapped to chromosomes of cattle through their segregation in a panel of bovine x rodent somatic cell hybrids. Genes for uroplakins IA, IB, and II were mapped to bovine (BTA) Chromosomes (Chrs) 18 (UPK1A), 1 (UPK1B), and 15 (UPK2), respectively. Two bovine genomic DNA sequences reactive with a uroplakin III cDNA probe were identified and mapped to BTA 6 (UPK3A) and 5 (UPK3B). We have also mapped genes for uroplakins IA and II in mice, to the proximal regions of mouse Chr 7 (Upk1a) and 9 (Upk2), respectively, by analyzing the inheritance of restriction fragment length variants in recombinant inbred mouse strains. These assignments are consistent with linkage relationships known to be conserved between cattle and mice. The mouse genes for uroplakins IB and III were not mapped because the mouse genomic DNA fragments reactive with each probe were invariant among the inbred strains tested. Although the stoichiometry of AUM proteins is nearly constant, the fact that the uroplakin genes are unlinked indicates that their expression must be independently regulated. Our results also suggest likely positions for two human uroplakin genes and should facilitate further analysis of their possible involvement in disease.

Animals↗
PubMed1993

Chromosomal localization of the lysozyme gene cluster in river buffalo (Bubalus bubalis L.).

Lysozyme (LYZ) is an antibacterial enzyme which allows the digestion of bacteria present in tears and saliva. In the true stomach of ruminants LYZ breaks open the bacteria of the foregut, which are subsequently digested by typical mammalian digestive enzymes, allowing the incorporation of nutrients from the bacteria. Southern analysis with a single exon from a cow lysozyme gene revealed that there are about 10 genes in ruminants (Irwin & Wilson 1989), while pig and primates have a single lysozyme gene (Swanson et al. 1991) and camels have two (Irwin et al. 1992). The higher number of LYZ genes in ruminants is believed to be the result of gene duplication associated with the evolution of foregut fermentation (Irwin et al. 1992). Recently, the genomic organization of the lysozyme gene family has been determined in domestic cattle, and, using a cocktail of genomic clones, the lysozyme gene cluster (LYZ/) was assigned to chromosome (Chr) 5, band 23 by fluorescence in situ hybridization (FISH) (Gallagher et al. 1993). In our continued effort to test the genetic homology of conserved chromosome banding regions between cattle and river buffalo, and to extend the river buffalo physical gene map, we have mapped the LYZ/ by FISH and R-banding.

Animals↗
PubMed1993

A genetic map of DNA loci on bovine chromosome 1.

We constructed a genetic map of most of the length of bovine chromosome 1 using the CSIRO and the Texas A&M University cattle reference families. Twelve loci are in a single linkage group, 9 of which are highly polymorphic loci. Four loci are of known biochemical function, alpha-1 crystallin (CRYA1), gamma-s crystallin (CRYG8), superoxide dismutase 1 (SOD1), and uridine monophosphate synthase (UMPS), and these have also been previously mapped in humans. The loci CRYA 1, CSRD 1613, GMBT 7, RM 95, SOD1, and UMPS had been previously assigned to bovine syntenic group U10, while CSRD 1613 and UMPS had also been assigned to chromosome 1 by in situ hybridization. All of the loci show statistically significant linkage to at least one other locus. The conserved loci indicate that there have been major rearrangements during the evolution of bovine chromosome 1 compared to other mammalian chromosomes. The estimate of the total length of the linkage group is 168 cM, which accords well with the predicted length based on chiasmata frequencies for the bovine genome and the relative size of chromosome 1 in the bovine genome.

Animals↗
PubMed1993

Type I interferon genes in cattle: restriction fragment length polymorphisms, gene numbers and physical organization on bovine chromosome 8.

Multiple, superimposed Type I interferon (IFN) restriction fragments were resolved following 72-92 h of horizontal electrophoresis. Restriction fragment length polymorphisms (RFLPs) for alpha IFN (IFNA), beta IFN (IFNB), omega IFN (IFNW) and trophoblast IFN (IFNT) genes were identified in HindIII, EcoRI and TaqI digestions from 313 cattle. RFLPs with codominant segregation in cattle pedigrees were considered alleles, and 19 distinct polymorphic Type I IFN loci (5 IFNA, 4 IFNB, 8 IFNW and 2 IFNT) were identified. Allele frequencies and observed heterozygosity values were calculated for each locus and several loci were considered highly informative for linkage analysis. Bovine IFN gene numbers (10 IFNA, 6 IFNB, 20 IFNW and 6 IFNT) were estimated from the number of polymorphic loci plus additional monomorphic hybridizing bands present in EcoRI and HindIII digestions. Physical linkage of the Type I IFN gene families on bovine chromosome 8 was demonstrated by pulsed field gel electrophoresis (PFGE). Hybridization of two or more IFN probes to similarly sized PFGE fragments suggested the tentative gene family order: IFNA/IFNW-IFNT-IFNB. These studies provide a basis for the development of more detailed genetic and physical maps of the bovine Type I IFNs.

Alleles↗
PubMed1993

Somatic cell mapping of the bovine prion protein gene and restriction fragment length polymorphism studies in cattle and sheep.

Brains affected by the progressive neurological disease bovine spongiform encephalopathy (BSE) contain scrapie-associated fibrils and the protease-resistant isoform of prion protein. The gene encoding the normal host prion protein (PRNP) has been mapped to human chromosome 20 and mouse chromosome 2 with the hamster cDNA probe pEA974. Using this probe and a panel of bovine-rodent hybrid somatic cells, we have mapped PRNP to bovine syntenic group U11 (100% concordancy). PRNP restriction fragment length polymorphisms (RFLPs) were detected with five of six enzymes (BglII, EcoRI, HindIII, MspI and TaqI) in sheep, in contrast to one of 16 enzymes (HincII) in cattle. Codominant segregation of the bovine HincII RFLP was demonstrated in six backcross pedigrees. While PRNP RFLPs are tightly linked to scrapie incubation period, and consequently susceptibility or resistance to disease in rodents and sheep, the relationship between the PRNP RFLPs and BSE incubation period has not been determined.

Alleles↗
PubMed1993

Chromosomal localization of omega and trophoblast interferon genes in cattle and river buffalo by sequential R-banding and fluorescent in situ hybridization.

Fluorescent in situ hybridization (FISH) of the cattle cDNA probe bTP-509 to RBA-banded cattle (Bos taurus L.) chromosomes confirmed the assignment of the omega (IFNW) and trophoblast (IFNT) interferon genes to chromosome 8q15. Using the same probe, these genes were also localized to river buffalo (Bubalus bubalis L.) chromosome 3q15 following sequential RBA-banding and FISH. The extensive G- and R-banding homology observed between cattle chromosome 8 and river buffalo chromosome arm 3q supports the conserved chromosomal location of the IFNW and IFNT genes in these two species.

Animals↗
PubMed1993

Type-I interferon genotypes and severity of clinical disease in cattle inoculated with bovine herpesvirus 1.

Genomic DNA samples and health records from 98 unrelated, mixed-breed cattle inoculated with bovine herpesvirus 1 (BHV-1) were examined to determine the relationship between interferon (IFN) genotype and severity of clinical disease. Cattle were retrospectively classified as moderately or severely affected on the basis of rectal temperature, feed intake, and weight gain after intranasal inoculation of BHV-1. Southern blot analysis of 16 type-I IFN genes identified alleles at 3 IFN loci (IFNB1, IFNW4, and IFNW8) that were significantly associated with the more severe clinical phenotype (odds ratios = 4.1 [P = 0.01], 2.3 [P < 0.05] and 2.4 [P = 0.06], respectively). A second allele at the IFNB1 locus was associated with the milder disease phenotype (odds ratio = 2.9, P < 0.05). These results indicate that selective breeding programs aimed at altering the frequency of these alleles in cattle populations may potentially improve animal health and lessen the economic impact of BHV-1 infection on cattle producers.

Alleles↗
PubMed1992

Syntenic mapping and chromosomal localization of bovine alpha and beta interferon genes.

The previous assignment of bovine alpha-(IFNA) and beta-(IFNB) interferon gene families to syntenic group U18 was confirmed with additional cDNA probes and a bovine-rodent hybrid somatic cell panel representing all 29 bovine autosomal syntenic groups. Fluorescent in situ hybridization (FISH) localized these genes to bovine Chromosome (Chr) 8 band 15 and demonstrates that with biotinylated plasmids, as few as five tandemly arrayed sequences can be detected by conventional fluorescent microscopy. This technique can be applied to physical mapping of other multicopy genes in domestic animals.

Animals↗
PubMed1989

Ulceration in the proximal portion of the urethra as a cause of hematuria in horses: four cases (1978-1985).

Sudden onset of hematuria was associated with mucosal ulceration of the proximal portion of the urethra in 1 stallion and 3 geldings. Hematuria was observed characteristically and consistently at the end of urination. Mucosal ulceration was identified endoscopically in the proximal portion of the urethra at the level of the ischial arch. Biopsy of an ulcerated area of the proximal urethra in one gelding revealed transitional cell carcinoma. Treatment regimens varied from systemic antimicrobial and/or vasoactive therapy to diversion of urinary flow via a temporary perineal urethrostomy. Hematuria resolved in 14 to 24 days (average, 20 days) after treatment was begun, except in one gelding that died of undetermined causes during an initial examination. In the 3 remaining horses, hematuria had not recurred for up to 9 years (average, 1 year).

Animals↗
PubMed1986

Acute myelomonocytic leukemia in a horse.

A 7-year-old Quarter Horse stallion with a myeloproliferative disorder was examined because of colic, and an enterolith was removed surgically. The horse experienced secondary complications after abdominal surgery, and leukopenia and thrombocytopenia were detected. Five months later, the horse was examined for recurrent peripheral edema and for repair of an abdominal incisional hernia. Acute myelomonocytic leukemia was diagnosed, and treatment with low-dose (noncytocidal) cytosine arabinoside was unsuccessful. Necropsy revealed neoplastic infiltrate in the spleen, liver, lung, adrenal gland, testes, and eye. The persistent hematologic abnormalities before the onset of overt leukemia may represent hematopoietic dysplasia or preleukemia.

Animals↗