Mapping of a Gene for Long QT Syndrome to Chromosome 4q25-27

Long QT syndrome (LQTS) is a heterogeneous inherited disorder causing syncope and sudden death from ventricular arrhythmias. A first locus for this disorder was mapped to chromosome 11p15.5. However, locus heterogeneity has been demonstrated in several families, and two other loci have recently been located on chromosomes 7q35-36 and 3p21-24. We used linkage analysis to map the locus in a 65-member family in which LQTS was associated with more marked sinus bradycardia than usual, leading to sinus node dysfunction. Linkage to chromosome 11p15.5, 7q35-36, or 3p21-24 was excluded. Positive linkage was obtained for markers located on chromosome 4q25-27. A maximal LOD score of 7.05 was found for marker D4S402. The identification of a fourth locus for LQTS confirms its genetic heterogeneity. Locus 4q25-27 is associated with a peculiar phenotype within the LQTS entity.     

The PiGMaP consortium linkage map of the pig (Sus scrofa)

A linkage map of the porcine genome has been developed by segregation analysis of 239 genetic markers. Eighty-one of these markers correspond to known genes. Linkage groups have been assigned to all 18 autosomes plus the X Chromosome (Chr). As 69 of the markers on the linkage map have also been mapped physically (by others), there is significant integration of linkage and physical map data. Six informative markers failed to show linkage to these maps. As in other species, the genetic map of the heterogametic sex (male) was significantly shorter (16.5 Morgans) than the genetic map of the homogametic sex (female) (21.5 Morgans). The sex-averaged genetic map of the pig was estimated to be 18 Morgans in length. Mapping information for 61 Type I loci (genes) enhances the contribution of the pig gene map to comparative gene mapping. Because the linkage map incorporates both highly polymorphic Type II loci, predominantly microsatellites, and Type I loci, it will be useful both for large experiments to map quantitative trait loci and for the subsequent isolation of trait genes following a comparative and candidate gene approach.     

Computer controlled fed-batch fermentation of the methylotroph Pseudomonas AM1

Summary A simple on-line computer control strategy based on dissolved oxygen level readings has been developed to control methanol addition during a fermentation of the methylotroph Pseudomonas AM1. This strategy has led to significant and reproducible improvements in the performance of the fermentation.     

Direct freezing of cattle embryos after partial dehydration at room temperature

A new and simple method for freezing of bovine morulae and blastocysts was developed. Embryos were predehydrated at room temperature, frozen at -30 degrees C (cooling rate = 12 degrees C/min), and plunged into liquid nitrogen. This method was compared in vitro and in vivo to the slow freezing method (0.3 degrees C/min to -30 degrees C). Predehydration of the embryos in 1.5M glycerol was achieved by sucrose solution that makes the cells osmotically shrink. After the predehydrated morulae and blastocysts were frozen and thawed, 6 .4% (33 52 ) were developed in vitro for 48h and 44.2% (23 52 ) were hatched. Development obtained with slowly frozen embryos were 70.8% (17 24 ) and 58.3% (14 24 ) respectively. After transfer to recipient heifers, 33.3% (7 21 ) of the embryos frozen according this new method developed normally into viable foetuses or calves. This was the case for 48.5% (16 33 ) of the slowly frozen embryos.     

High frequency of-β-hexosaminidase deficiency in lymphoblastoid cell lines

The activity of seven lysosomal enzymes was determined in 25 lymphoblastoid cell lines. These lines included normal controls transformed with Epstein-Barr virus, Burkitt's lymphomas and other lymphomas with or without EBV genome.Four lines were deficient in total β-hexosaminidase activity. The deficiency was as severe as that of the variant O (Sandhoff's disease) of clinical β-hexosaminidase deficiency. The electrophoretic pattern was also similar to that observed in Sandhoff's disease.The possible mechanisms explaining the high frequency of β-hexosaminidase deficiency in lymphoblastoid cell lines are discussed.     

Spot position of rat liver ribosomal proteins by four different two-dimensional electrophoreses in polyacrylamide gel

Summary Separation of the proteins from rat liver 40S and 60S ribosomal subunits and polysomes was done in four different two-dimensional polyacrylamide gel electrophoresis systems. The first dimension was run at acidic or basic pH, the second dimension either with sodium dodecyl sulphate or at acidic pH in 18% acrylamide. The position of each individual protein of both subunits and polysomes was determined in each system. This identification resulted from a new method avoiding any previous purification of individual proteins. The new proposed uniform nomenclature for mammalian ribosomal proteins (McConkey et al. in press) was used for numbering the proteins in the four systems.     

Nouvelles formulations des regles ecologiques connues sous le nom de reegle de Bergmann et loi de Jordan: Amendments of the ecological rules known as Bergmann's and Jordan's rules

Measurements of populations of planktonic and micronektonicspecies from the Atlanto-mediterranean region (about 10,000specimens) have lead to improvements in Bergmann's rule relatingto the increase in size with latitude. There are three cases : Mediterranean specimens may be smaller(e.g. the mysid Eucopia hansent), equal to (e.g. the decapodcrustacean Gennadas elegans) or larger than Atlantic ones (e.g.the thecosomatous genus Cymbulia). All the species in the last group have their principal distributionin warm ocean waters. In the Atlantic, tropical species (e.g.the euphausiid Euphausia gibboides) decrease in size in thenorthern parts of their range while temperate species (e.g.the decapod crustacean Sergesles corniculum) decrease in sizetowards both the pole and the equator. The comparison with the number of vertebrae of fish, which increasesas does the size according to Jordan's rule, is interesting:though correct for cold water species (e.g. Merlucdus merluccius),this rule cannot be applied to warm water species (e.g. Merlucciussenegalensis). Thus, these rules must be corrected like this:- "a species reachesits maximal size in high, intermediate or low latitudes of itsarea if it has a boreal, temperate or tropical distribution"; - "the number of vertebrae increases with latitude for borealfish and decreases for tropical ones".     

Stimulation of shoot regeneration from cotyledons of Helianthus annuus by the ethylene inhibitors,silver and cobalt

The effects of CoCl₂, AgNO₃ and ethylene released by exogenous 2-chloroethylphosphonic acid (Ethephon), were studied on shoot regeneration from cotyledons of Helianthus annuus cv. E8206R, a poorly regenerative cultivar. Inhibition of ethylene biosynthesis by CoCl₂, at concentrations of 20 K, provoked a substantial enhancement of shoot regeneration (30 %): the control was poorly regenerative. However, CoCl₂ had no effect when Ethephon was supplied. Inhibition of ethylene action by AgNO₃, at concentrations of 10–25 M, caused a significant increase in plant regeneration: 25 % instead of 1.2 % in the control. Furthermore, addition of Ethephon to AgNO₃-treated tissues failed to reduce the stimulation of shoot regeneration caused by AgNO₃. On the basis of these findings, it is suggested that ethylene inhibits the regeneration process from cotyledons of sunflower.Abbreviations NAA 1-naphthalene acetic acid - BAP 6-benzylamino-purine - GA₃ gibberellic acid - Ethephon 2-chloroethylphosphonic acid - MS Murashige and Skoog medium - AVG aminoethoxyvinylglycine