Polymorphism and Gene Conversion in Mouse α-Globin Haplotypes

We have cloned and characterized three distinct alpha-globin haplotypes obtained from inbred strains of the mouse, Mus domesticus. We report here the complete nucleotide sequence of the six alpha-globin genes that the haplotypes contain. Our analysis of these genes and those from one other previously described haplotype indicates that recurrent gene conversion events have played a major role in their history. The pattern of nucleotide substitutions suggests that conversions have occurred both within and between haplotypes. Limited segments of coding and noncoding DNA have been involved in these gene conversion events. In two of the haplotypes, the nonallelic genes of each maintain DNA sequence identity over discrete intervals and encode the same alpha-globin polypeptide. On the other hand, the coding regions of some genes have accumulated replacement changes that result in distinct alpha-globins. In one instance, these changes appear to reflect positive selection of advantageous mutations.     

Structural organization of the beta-globin locus of B-haplotype sheep

Goats and some sheep synthesize a juvenile hemoglobin, Hb C (alpha 2 beta C2), at birth and produce this hemoglobin exclusively during severe anemia. Sheep that synthesize this juvenile hemoglobin are of the A haplotype. Other sheep, belonging to a separate group, the B haplotype, do not synthesize hemoglobin C and during anemia continue to produce their adult hemoglobin. To understand the basis for this difference we have determined the structural organization of the beta- globin locus of B-type sheep by constructing and isolating overlapping genomic clones. These clones have allowed us to establish the linkage map 5' epsilon I-epsilon II-psi beta I-beta B-epsilon III-epsilon IV- psi beta II-beta F3' in this haplotype. Thus, B sheep lack four genes, including the BC gene, and have only eight genes, compared with the 12 found in the goat globin locus. The goat beta-globin locus is as follows: 5' epsilon I-epsilon II-psi beta X-beta C-epsilon III-epsilon IV-psi beta Z-beta A-epsilon V-epsilon VI-psi beta Y-beta F3'. Southern blot analysis of A-type sheep reveals that these animals have a beta- globin locus similar to that of goat, i.e., 12 globin genes. Thus, the beta-globin locus of B-haplotype sheep resembles that of cows and may have retained the duplicated locus of the ancestor of cows and sheep. Alternatively, the B-sheep locus arrangement may be the result of a deletion of a four-gene set from the triplicated locus.      

Identification of a alpha-NeuAc-(2----3)-beta-D-galactopyranosyl N-acetyl-beta-D-galactosaminyltransferase in human kidney

Microsomal preparations from human kidney were found to contain enzymic activity capable to transfer N-acetylgalactosamine from UDP-N-acetylgalactosamine to native bovine fetuin. The acceptor structures on the fetuin molecules were identified as N- as well as O-linked glycans with a markedly higher incorporation into the N-linked carbohydrate chains. Analysis of the alkali-labile transferase products by thin-layer chromatography indicated that the enzyme is able to synthesize structures having mobilities identical with those found on glycophorin from Cad erythrocytes. Mild acid treatment and enzymic hydrolysis with N-acetylhexosaminidase from jack beans of the N-linked transferase products suggested that beta-D-GalpNAc-(1----4)-[alpha-NeuAc-(2----3)]-beta-D-Galp-(1----s tructures were formed by the enzymic reaction on both N- and O-linked acceptors. The enzyme might, therefore, be involved in the biosynthesis of Sda (and Cad) antigenic structures. By use of various oligosaccharides, glycopeptides, and glycolipids having well characterized carbohydrate sequences, the acceptor-substrate specificity of the N-acetylgalactosaminyltransferase was determined. The enzyme generally recognized alpha-NeuAc-(2----3)-beta-D-Gal groups as acceptors, but in a certain conformation. Thus, tri- and tetra-saccharide alditols, native human glycophorin A, and GM3 were not acceptor substrates although they carry the potential disaccharide acceptor unit. When these structures were presented as sialyl-(2----3)-lactose or as a tryptic peptide from glycophorin A, they were shown to be rather good acceptor substrates for the N-acetyl-beta-D-galactosaminyltransferase from human kidney.     

Identification of a novel ganglioside on erythrocytes with blood group Cad specificity

The blood group Cad antigen is a carbohydrate structure well characterized on the sialoglycoproteins of the red cell membrane from some rare individuals (Blanchard, D., Cartron, J. P., Fournet, B., Montreuil, J., Van Halbeck, H., and Vliegenthart, J.F.G. (1983) J. Biol. Chem. 258, 7691-7695). However, protease treatment of whole cells did not destroy their antigenic activity which indicated that glycolipid might also be involved in the antigenic reaction. A crude ganglioside fraction was prepared from Cad cells and found to inhibit the hemagglutination reaction, whereas neutral glycolipids were inactive. Further analysis of the ganglioside extract from Cad erythrocytes by thin layer chromatography revealed an unusual profile characterized by a lower content of sialosylparagloboside and the presence of a novel ganglioside of slower mobility. Immunochemical studies demonstrate that this ganglioside binds Helix pomatia lectin and inhibits human anti-Sda antibody. In addition, a ganglioside with identical chromatographic mobility can be obtained by the enzymatic transfer of GalNAc from UDP-GalNAc to sialosylparagloboside using a microsomal preparation from human kidney. These results together with cell surface labeling experiments suggest that the major ganglioside of Cad erythrocytes might be derived from sialosylparagloboside by substitution with an additional N-acetylgalactosamine residue.     

Selective inhibition of prostaglandin biosynthesis by gold salts and phenylbutazone

Gold salts and phenylbutazone selectively inhibit the synthesis of PGF_2α and PGE₂ respectively. Lowered production of one prostaglandin species is accompanied by an increased production of the other. Selective inhibition by these drugs was observed in the presence of adrenaline, reduced glutathione and copper sulphate under conditions when most anti-inflammatory compounds inhibited PGE₂ and PGF_2α syntheses equally. It is postulated that selective inhibitors may have a different mode of action and beneficial effects may be related to the endogenous ratio of PGE to PGF required for normal function.     

Clinical Implications of the Cervical Papanicolaou Test Results in the Management of Anal Warts in HIV-Infected Women

The Papanicolaou test (or Pap test) has long been used as a screening tool to detect cervical precancerous/cancerous lesions. However, studies on the use of this test to predict both the presence and change in size of genital warts are limited. We examined whether cervical Papanicolaou test results are associated with the size of the largest anal wart over time in HIV-infected women in an on-going cohort study in the US. A sample of 976 HIV-infected women included in a public dataset obtained from the Women’s Interagency HIV Study (WIHS) was selected for analysis. A linear mixed model was performed to determine the relationship between the size of anal warts and cervical Pap test results. About 32% of participants had abnormal cervical Pap test results at baseline. In the adjusted model, a woman with a result of Atypia Squamous Cell Undetermined Significance/Low-grade Squamous Intraepithelial Lesion (ASCUS/LSIL) had an anal wart, on average, 12.81 mm² larger than a woman with normal cervical cytology. The growth rate of the largest anal wart after each visit in a woman with ASCUS/LSIL was 1.56 mm² slower than that of a woman with normal cervical results. However, they were not significant (P = 0.54 and P = 0.82, respectively). This is the first study to examine the relationship between cervical Pap test results and anal wart development in HIV-infected women. Even though no association between the size of anal wart and cervical Pap test results was found, a screening program using anal cytology testing in HIV-infected women should be considered. Further studies in cost-effectiveness and efficacy of an anal cytology test screening program are warranted.     

Two silicone nontoxic fouling release coatings: Hydrosilation cured PDMS and CaCO3 filled,ethoxysiloxane cured RTV11

Two silicone coatings have been evaluated for barnacle adhesion. One coating is an unfilled hydrosilation cured polydimethylsiloxane (PDMS) network, while the other is a room temperature vulcanized (RTV), filled, ethoxysiloxane cured PDMS elastomer, RTV11^?. The adhesion strength of one species of barnacle, Balanus eburneus, to the hydrosilation coatings is in the range of 0.37–0.60 kg cm^‐2 while the corresponding range for RTV11 is 0.64–0.90 kg cm^‐2. The easier release of B. eburneus from the hydrosilation cured network compared to RTV11 is discussed in relationship to differences in bulk and surface properties. Preliminary results suggest bulk modulus may be the most important parameter in determining barnacle adhesion strength. In light or mechanical property analysis, a re‐evaluation of surface properties and chemical stability is presented.     

Synthesis and biological evaluation of new UDP-GalNAc analogues for the study of polypeptide-alpha-GalNAc-transferases

A series of three O-methylated UDP-GalNAc analogues have been synthesised using a divergent strategy from a 3,6-di-O-pivaloyl GlcNAc derivative. The biological activity of these probes toward polypeptide-alpha-GalNAc-transferase T1 has been investigated. This study shows that this glycosyltransferase exhibits a very high substrate specificity.