Microsatellite evolution in congeneric mammals: domestic and bighorn sheep

We compared genotypes at eight (AC)n microsatellite loci in domestic sheep (Ovis aries) and wild Rocky Mountain bighorn sheep (O. canadensis). The domestic sheep had greater genetic variation, higher allele-size variances, and larger allele sizes than the wild sheep. Accumulating evidence from higher taxonomic comparisons shows that these parameters are biased if microsatellite loci are selected in one taxon and used in another. Our results demonstrate similar biases between congeneric species. We compared standard measures of genetic variation, differentiation, and distance within and between species (H, D, FST) to newer measures based on allele-size variance (SW, SB, RST). The size-based distances better detected species-level divergence, but standard measures better distinguished allopatric populations. Empirical calibration of these measures at the subspecies level is needed to establish their useful ranges.      

Modulation of whole body protein metabolism, during and after exercise, by variation of dietary protein

The aim of this study was to investigate dietaryprotein-induced changes in whole body leucine turnover and oxidationand in skeletal muscle branched chain 2-oxo acid dehydrogenase (BCOADH) activity, at rest and during exercise. Postabsorptive subjects receiveda primed constant infusion ofL-[1-¹³C,¹⁵N]leucinefor 6 h, after previous consumption of a high- (HP; 1.8 g · kg¹ · day¹,n = 8) or a low-protein diet (LP; 0.7 g · kg¹ · day¹,n = 8) for 7 days. The subjects werestudied at rest for 2 h, during 2-h exercise at 60% maximum oxygenconsumption, then again for 2 h at rest. Exercise induced a doubling ofboth leucine oxidation from 20 µmol · kg¹ · h¹and BCOADH percent activation from 7% in all subjects. Leucine oxidation was greater before (+46%) and during (+40%,P < 0.05) the first hour of exercisein subjects consuming the HP rather than the LP diet, but there was noadditional change in muscle BCOADH activity. The results suggest thatleucine oxidation was increased by previous ingestion of an HP diet,attributable to an increase in leucine availability rather than to astimulation of the skeletal muscle BCOADH activity.

     

Nucleotide sequence of the Acinetobacter calcoaceticus trpGDC gene cluster

A plasmid library of Acinetobacter calcoaceticus HindIII fragments was constructed, and clones that complemented an Escherichia coli pabA mutant were selected. Plasmids containing a 3.9-kb fragment of A. calcoaceticus DNA that also complemented E. coli trpD and trpC-(trpF+) mutants were obtained. We infer that complementation of E. coli pabA mutants was the result of the expression of the amphibolic anthranilate- synthase/p-aminobenzoate-synthase glutamine-amidotransferase gene and that the plasmid insert carried the entire trpGDC gene cluster. In E. coli minicells, the plasmid insert directed the synthesis of polypeptides of 44,000, 33,000, and 20,000 daltons, molecular masses that are consistent with the reported molecular masses of phosphoribosylanthranilate transferase, indoleglycerol-phosphate synthase, and anthranilate-synthase component II, respectively. A 3,105- bp nucleotide sequence was determined. Comparison of the A. calcoaceticus trpGDC sequences with other known trp gene sequences has allowed insight into (1) the evolution of the amphibolic trpG gene, (2) varied strategies for coordinate expression of trp genes, and (3) mechanisms of gene fusions in the trp operon.      

Role of Plasma Carcinoembryonic Antigen in Diagnosis of Gastrointestinal,Mammary, and Bronchial Carcinoma

Our studies have confirmed that raised plasma levels of carcinoembryonic antigen (C.E.A.) occur with many but not all malignant tumours, particularly those of the gastrointestinal tract, breast, and bronchus. However, the incidence of raised values may reach 30% in diseases associated with inflammation or regeneration or both. Consequently, it cannot serve yet as a routine screening test for cancer. Effective surgical therapy results in high plasma C.E.A. levels returning to normal. Subsequent rises appear to develop with tumour recurrence or spread. At present the most useful role for C.E.A. seems to be in monitoring patients during the post-therapeutic followup period. Further basic work is required before C.E.A. can become of routine medical value.     

Distributions of two recently inserted long interspersed elements of the L1 repetitive family at the Alb and beta h3 loci in wild mice populations

The presence of the L1 sequences, L1Md4 next to the pseudogene beta h3 and I12 found in the twelfth intron of the albumin gene, in certain strains of laboratory mice but not of others has led to the suggestion that these sequences were recent insertions into the Mus mus domesticus genome. To be sure that they are really recent insertions and not relics of an ancestral chromosome, we investigated the presence or absence of these sequences in populations of wild mice belonging to the semispecies M. m. domesticus and M. m. musculus as well as in other species of the genus Mus and in related murids. The sequence I12 in the albumin gene was found in 34% of the chromosomes of the wild mice belonging to M. m. domesticus and to a lesser extent (6%) in M. m. musculus. Of 114 M. m. domesticus chromosomes, L1Md4 was found in only nine, seven of which came from the same locality. Its presence was associated with the haplotype Hbbp, which is relatively rare in European populations of M. musculus. Since there was no evidence for the presence of these two L1 sequences in more distantly related species, we conclude that they are recent insertions in the M. musculus genome.      

Protein and m-RNA expression of farnesyl-transferases,RhoA and RhoB in rat liver hepatocytes: action of perillyl alcohol and vitamin A <Emphasis Type="BoldItalic">in vivo</Emphasis>.

Summary We analysed the action, in rats in vivo, of the protein isoprenylation inhibitor perillyl alcohol (POH) and that of vitamin A, alone or in association, on m-RNA and protein expression of farnesyltransferases (FTases α and β subunits) and their protein substrates RhoA and RhoB, in isolated hepatocytes. Combined administration of POH and vitamin A induced a sharp decrease in FTase α protein after 96 h, suggesting an involvement not only of farnesyltransferases but also of geranylgeranyltransferases, which share the FTase α protein. FTase β protein did not decrease. POH plus vitamin A, in contrast with POH or vitamin A alone, induced a decrease in RhoB protein, probably because of different cleavages. No modification was observed in RhoA protein. Vitamin A alone increased RhoB m-RNA and protein expression. As one of the functions of RhoB is cell polarisation, these data support our previous hypothesis of a polarised transport of vitamin A from hepatocytes to hepatic stellate cells. As the behaviours of m-RNAs and proteins in this study were often different, cytoplasmic metabolic pathways must be considered for the parameters studied. The behaviour of Rho B, which is thought to have an antioncogene function, is discussed in view of its isoprenylated forms in the membranes. These preliminary findings stress the need, when studying the association of two isoprenoids in cancer therapy, to consider normal as well as tumour-bearing animals.     

ddrage: A data set generator to evaluate ddRADseq analysis software

High‐throughput sequencing makes it possible to evaluate thousands of genetic markers across genomes and populations. Reduced‐representation sequencing approaches, like double‐digest restriction site‐associated DNA sequencing (ddRADseq), are frequently applied to screen for genetic variation. In particular in nonmodel organisms where whole‐genome sequencing is not yet feasible, ddRADseq has become popular as it allows genomewide assessment of variation patterns even in the absence of other genomic resources. However, while many tools are available for the analysis of ddRADseq data, few options exist to simulate ddRADseq data in order to evaluate the accuracy of downstream tools. The available tools either focus on the optimization of ddRAD experiment design or do not provide the information necessary for a detailed evaluation of different ddRAD analysis tools. For this task, a ground truth, that is, the underlying information of all effects in the data set, is required. Therefore, we here present ddrage , the ddRA D Data Set Ge nerator, that allows both developers and users to evaluate their ddRAD analysis software. ddrage allows the user to adjust many parameters such as coverage and rates of mutations, sequencing errors or allelic dropouts, in order to generate a realistic simulated ddRADseq data set for given experimental scenarios and organisms. The simulated reads can be easily processed with available analysis software such as stacks or pyrad and evaluated against the underlying parameters used to generate the data to gauge the impact of different parameter values used during downstream data processing.     

Lotus corniculatus nodulation specificity is changed by the presence of a soybean lectin gene

Plant lectins have been implicated as playing an important role in mediating recognition and specificity in the Rhizobium-legume nitrogen-fixing symbiosis. To test this hypothesis, we introduced the soybean lectin gene Le1 either behind its own promoter or behind the cauliflower mosaic virus 35S promoter into Lotus corniculatus, which is nodulated by R. loti. We found that nodulelike outgrowths developed on transgenic L. corniculatus plant roots in response to Bradyrhizobium japonicum, which nodulates soybean and not Lotus spp. Soybean lectin was properly targeted to L. corniculatus root hairs, and although infection threads formed, they aborted in epidermal or hypodermal cells. Mutation of the lectin sugar binding site abolished infection thread formation and nodulation. Incubation of bradyrhizobia in the nodulation (nod) gene-inducing flavonoid genistein increased the number of nodulelike outgrowths on transgenic L. corniculatus roots. Studies of bacterial mutants, however, suggest that a component of the exopolysaccharide surface of B. japonicum, rather than Nod factor, is required for extension of host range to the transgenic L. corniculatus plants.