Molecular basis and PCR-DNA typing of the Fya/fyb blood group polymorphism

Spondyloepiphyseal dysplasia tarda (SEDL) is an X-linked recessive disorder characterized in affected males by short stature resulting from a growth defect of the vertebral bodies. We have extended our earlier studies by analyzing 15 families with newly identified microsatellite DNA markers; analysis of recombination events with these markers indicates that the gene responsible for SEDL is located in Xp22 between DXS 16 and DXS 987 on an interval spanning approximately 2 Mb.     

Localization of the CDKN4/p27Kip1 gene to human chromosome 12p12.3

CDKN4/p27Kip1 is a cyclin-dependent kinase (Cdk) inhibitor implicated in G1 phase arrest, which negatively regulates G1 phase progression in response to TGF, and might represent a tumor suppressor gene. We report here the chromosomal assignment of the human CDKN4 gene to chromosome 12p12.3 in close proximity to highly polymorphic microsatellite markers.     

Decline in photopositive tendencies with age inDrosophila melanogaster (Diptera: Drosophilidae)

Phototaxis was measured in young, middle-aged, and oldDrosophila melanogaster flies of both sexes. The apparatus allowed us to measure the tendency to go toward light, independently of the time needed to do so; under such conditions, phototaxis is dissociated from locomotor activity. The percentage of photopositive flies decreased slightly with age (93.96, 80.17, and 78.97%, respectively, in young, middle-aged, and old flies). Results are discussed in connection with previous data for which the tendency to go toward light and the time to do so were not dissociated.     

Enzyme-linked immunosorbent assay (ELISA) using a glycolipid antigen for the serodiagnosis of melioidosis

Abstract The serodiagnosis of melioidosis is commonly performed with tests using protein or polysaccharide as antigen. However, due to the low sensitivity, specificity and difficulty in the preparation of the antigens, more simple, precise and reproducible diagnostic tests were required. A purified glycolipid antigen (GL) which is a specific lipid component of Burkholderia pseudomallei has been used in an ELISA. With this antigen, specific immunoglobulin G (IgG) was detected in 49 out of 50 melioidosis sera. IgG was also detected in 2 out of 185 (Japanese) and 16 out of 181 (Vietnamese) control sera. Thus, the sensitivity was 98.0%, and specificity was 98.9% and 91.1% in the Japanese and Vietnamese sera, respectively. When the ELISA and indirect haemagglutination (IHA) tests were combined, a sensitivity of 100% and specificity of 97.8% were achieved. The advantages of the glycolipid antigen are ease of preparation, stability, high sensitivity and specificity.     

Roles for mannose-6-phosphate receptors in lysosomal enzyme sorting, IGF-II binding and clathrin-coat assembly

Two related transmembrane proteins in mammalian cells bind the mannose 6-phosphate recognition marker present on all soluble lysosomal hydrolases. Recent studies of cells that express only one or neither of these proteins have shed light not only on their function in directing lysosomal enzymes into the endocytic pathway but also on their critical role in transport vesicle formation in the trans Golgi network. One of these proteins also binds insulin-like growth factor II (IGF-II) and may be an important part of the IGF-dependent system that regulates development.     

Entrapment of l-tryptophan producing Escherichia coli in different matrices: activity of immobilized cells

Cells of Escherichia coli induced for l-tryptophan synthase [l-serine hydro-lyase (adding indole-glycerol-phosphate), EC 4.2.1.20] have been assayed in DMF and DMSO aqueous solvents as reaction medium. Up to 20% DMF/water, cells retained 90% of their tryptophan synthase activity. Concentrations of 20 mM indole, which did not inhibit this reactivity, could be reached with 5% DMF/water. Four matrices were compared for cell immobilization: polyacrylamide, foam particles of bovine seum albumin, alginate and κ-carrageenan. The best activity was retained with the latter matrix, and the preparations thus obtained allowed high productivity of l-tryptophan. Various systems of production of l-tryptophan with κ-carrageenan and DMF/water were studied.     

Synthesis of [17,18-3H] trans-13-azaprostanoic acid. A labeled probe for the PGH2/TXA2 receptor

Because of its highly unstable nature, TXA2, produced by platelet metabolism of arachidonic acid, does not lend itself to use as a receptor probe for its own receptor. As such, the stable TXA2/PGH2 antagonist, trans-13-azaprostanoic acid (trans-13-APA, 12b), was prepared as the [17, 18 3H] derivative [( 3H] trans-13-APA, 12c) to study this receptor and to better evaluate the mechanism of action of these azaprostanoids. Tritiated trans-13-APA, 12c, was prepared in nearly theoretical specific activity (57 Ci/mmole) from (17Z)-trans-13-azaprost-17-enoic acid (11b) by catalytic tritiation. The unsaturated 11b was prepared by condensation of cis-7-amino-3-heptene (8) with 2-(6-carboxyhexyl) cyclopentanone (9), NaBH4 reduction, chromatography, and hydrolysis of the trans isomer so isolated. The olefins 11a and b were also of biochemical interest because of the unsaturation in the lower side chain. The presence of similar unsaturation in PGH3(4) and TXA3 (3) renders these prostaglandins inactive as proaggregatory agents. Evaluation of the antiaggregatory activity of 11a and b indicated it to be about the same potency in inhibiting human platelet aggregation as the parent cis and trans-13-APAs, suggesting that introduction of a double bond at the 17 position in platelet prostaglandin antagonists is unlikely to result in enhanced antiplatelet activity.     

Amplification and excision of integrated polyoma DNA sequences require a functional origin of replication

Cells transformed by Polyoma virus (Py) can undergo a high rate of excision or amplification of integrated viral DNA sequences, and these phenomena require the presence of homology (i.e., repeats) within the viral insertion as well as a functional viral large T antigen (T-Ag). To determine whether the main role of large T-Ag in excision and amplification was replicative or recombination-promoting, we studied transformed rat cell lines containing tandem insertions of a ts-a Py molecule (encoding a thermolabile large T-Ag) with a deletion of the origin of viral DNA replication. Culturing of these cells at the temperature permissive for large T-Ag function did not result in any detectable excision or amplification of integrated Py sequences. We then introduced into origin-defective lines a recombinant plasmid containing the viral origin of replication and the gene coding for resistance to the antibiotic G418. All G418-resistant clones analyzed readily amplified the integrated plasmid molecules when grown under conditions permissive for large T-Ag function, showing that these cells produced viral large T-Ag capable of promoting amplification in trans of DNA sequences containing the Py origin. These observations strongly suggest that Polyoma large T antigen promotes excision or amplification of viral DNA by initiating replication at the integrated origin, providing a favorable substrate for subsequent recombination.     

Prey selection within a size-class of mussels, Mytilus edulis, by oystercatchers, Haematopus ostralegus

By comparing the shells of those mussels Mytilus edulis that had been opened by oystercatchers Haematopus ostralegus with mussels of similar size that had not been opened, it was shown that oystercatchers that break into their prey by hammering a hole in the shell selected between prey within a size-class. Ventral hammerers selected mussels that were relatively thin on the ventral surface, were brown in colour and carried few barnacles. Dorsal hammerers selected eroded mussels with thin dorsal shells. Stabbing oystercatchers did not select for thin-shelled prey. In conjunction with the great individual variation in flesh content between mussels of the same length, prey size in this case can be only a poor predictor of prey profitability.