Sublocalization of an Ataxia-Telangiectasia Gene Distal to D11S384 by Ancestral Haplotyping In Costa Rican Families

In an effort to localize a gene for ataxia-telangiectasia (A-T), we have genotyped 27 affected Costa Rican families, with 13 markers, in the chromosome 11q22-23 region. Significant linkage disequilibrium was detected for 9/13 markers between D11S1816 and D11S1391. Recombination events observed in these pedigrees places A-T between D11S1819 and D11S1960. One ancestral haplotype is common to 24/54 affected chromosomes and roughly two-thirds of the families. Inferred (ancestral) recombination events involving this common haplotype in earlier generations suggest that A-T is distal to D11S384 and proximal to D11S1960. Several other common haplotypes were identified, consistent with multiple mutations in a single gene. When considered together with all other evidence, this study further sublocalizes the major A-T locus to ≈200 kb, between markers S384 and S535.     

Airborne grass pollen in Granada (Spain)

We have carried out a study on the annual and daily pollen concentrations from Gramineae over four consecutive years in the atmosphere of Granada (Spain). Samples of pollen grains were collected by the volumetric method with the aid of a Burkard sporetrap. Gramineae, according both to their high sensitizing capacity and to data from allergologists, are responsible for many pollinoses diagnosed in this area. In this work, daily pollen levels from April to July are monitored and the variations identified are interpreted in relation to meteorological conditions. Results indicated that the highest airborne concentrations of Gramineae pollen were found in May and June, although the beginning and intensity of pollination have been variable during these 4 years.     

Plasmid rolling circle replication and its control

Abstract This review summarises current information on rolling circle replicating plasmids originally isolated from Gram-positive bacteria with a low guanine and cytosine content in their DNA. It focuses on the peculiar biological features of these small, high copy number plasmids that replicate via an asymmetric RC mechanism. The regulation of plasmid copy number is also discussed.     

First evidence of human meconium glycoasparagines

During a systematic study of carbohydrate material present inhuman meconium, in addition to the previously described mucins,glycolipids and free oligosaccharides, we have now characterizeda significant quantity of free glycoasparagines. These glycoasparagineshave been isolated from human meconium by a combination of ion-exchange,concanavalin A (ConA)-affinity and high-performance liquid (HPLC)chromatographies. Their structures have been established by400 MHz ¹H-NMR spectroscopy. These compounds are related toN-acetyllactosaminic type structures and are based on the commoncore These glycoasparagines are probably derived from both proteaseand partial exoglycosidase hydrolysis of fetal gastrointestinalN-glycosyl proteins. Their structures are discussed in the contextof the known catabolic pathways of N-glycans glycoasparagine N-glycosyl protein catabolism meconium NMR     

Ultraviolet light sensitivity of carotene-and cytochrome-c-accumulating strains of the smut fungusUstilago violacea

White, pink, orange, and yellow strains ofUstilago violacea containing high and low levels of cytochrome c and various carotenes were exposed to ultraviolet light. The survival curves for all strains were of exponential decay form, but the carotene-accumulating strains were generally more resistant to UV than those strains with no carotenes at all. The UV exposure time leading to 90% loss in viability, LD₉₀, was quantitatively related to the carotene content in the form of a power function, where LD₉₀ increased as the fifth root of the total carotene content per cell. We also determined that the ratio of total carotenes to total cytochrome c per cell was quantitatively related to the rate of viability loss during UV exposure.     

A fetal skeletal muscle actin mRNA in the mouse and its identity with cardiac actin mRNA

We compare a recombinant cDNA plasmid (pAF81) complementary to a fetal skeletal muscle actin mRNA with a plasmid (pAM91) complementary to the actin mRNA expressed in adult skeletal muscle. The two mRNAs are significantly diverged in silent nucleotide positions; they are coexpressed in fetal skeletal muscle, and in differentiating muscle cell cultures their accumulation begins coordinately. The sequence of pAF81 shows that the amino acid sequence of mouse fetal skeletal muscle actin is almost identical to that of adult bovine cardiac actin. Hybridization of pAF81 to RNA from different mouse tissues shows that fetal skeletal muscle actin mRNA is very homologous or identical to fetal and adult cardiac actin mRNA. Only one gene homologous to pAF81 is detected on blots of restricted mouse DNA. We conclude that this gene must be expressed both in fetal skeletal muscle and in fetal heart. Whereas mRNA transcribed from this gene is the major actin mRNA species in adult heart, it is present in low amounts, if at all, in adult skeletal muscle.     

Bicyclo[3,2,1]octanoid,neolignans from Aniba simulans

Six bicyclo[3,2,1]octanoid neolignans, isolated from the benzene extract of Aniba simulans Allen (Lauraceae) trunk wood, are shown to derive from two basic structures: 1-allyl-8-hydroxy-6-(3′-methoxy-4′,5′-methylenedioxyphenyl)-7-methyl-3-oxobicyclo[3,2,1]octane, substituted by 4-hydroxy, 4-hydroxy-5-methoxy, 4-methoxy or 4,5-dimethoxy groups; and 1-allyl-8-hydroxy-6-(3′-methoxy-4′,5′-methylenedioxyphenyl)-7-methyl-4-oxobicyclo[3,2,1]oct-2-ene, substituted by 3-hydroxy or 3-hydroxy-5-methoxy groups. The structural proposals are based on spectral data, interconversions synthesis of a derivative from the known (2R,3S,3aS)-3a-allyl-5-methoxy-2-(3′-methoxy,4′,5′-methylenedioxyphenyl)-3-methyl-2,3,3a,6-tetrahydro-6-oxobenzofuran.