A nutrient drink test to assess maximum tolerated volume and postprandial symptoms: effects of gender, body mass index and age in health.

To assess the effects of age, gender and body mass index on the maximum tolerated volume of a nutrient drink and postprandial symptoms in health. Healthy adolescents (15 M, 15 F, aged 13-17 years) and adults (15 M, 25 F, aged 19-51 years) ingested Ensure (1 kcal mL-1) at a rate of 30 mL min-1. The maximum tolerated volume was recorded. Thirty minutes later, bloating, fullness, nausea and pain were rated using visual analogue scales. The Mann-Whitney test was used for comparisons between groups using body mass index and maximum tolerated volume as covariates. Age-related differences in maximum tolerated volume were noted between adolescents and adults, and were observed in both genders. Adults had higher scores for bloating and pain, and lower scores for fullness. Gender-related differences in maximum tolerated volume were noted in the group as a whole, and separately for adolescents and adults. Females had higher scores for nausea and pain. Gender and age-related differences in the maximum tolerated volume of a nutrient drink and postprandial symptoms should be considered in future studies of upper gastrointestinal symptoms in disease. Body mass index does not appear to influence maximum tolerated volume beyond its association with age and gender.

Bay-0 x Shahdara recombinant inbred line population: a powerful tool for the genetic dissection of complex traits in Arabidopsis.

Natural genetic variation in Arabidopsis is considerable, but has not yet been used extensively as a source of variants to identify new genes of interest. From the cross between two genetically distant ecotypes, Bay-0 and Shahdara, we generated a Recombinant Inbred Line (RIL) population dedicated to Quantitative Trait Locus (QTL) mapping. A set of 38 physically anchored microsatellite markers was created to construct a robust genetic map from the 420 F6 lines. These markers, evenly distributed throughout the five chromosomes, revealed a remarkable equilibrium in the segregation of parental alleles in the genome. As a model character, we have analysed the genetic basis of variation in flowering time in two different environments. The simultaneous mapping of both large- and small-effect QTLs responsible for this variation explained 90% of the total genotypic variance. Two of the detected QTLs colocalize very precisely with FRIGIDA and FLOWERING LOCUS C genes; we provide information on the polymorphism of genes confirming this hypothesis. Another QTL maps in a region where no QTL had been found previously for this trait. This confirms the accuracy of QTL detection using the Bay-0 x Shahdara RIL population, which constitutes the largest in size available so far in Arabidopsis. As an alternative to mutant analysis, this population represents a powerful tool which is currently being used to undertake the genetic dissection of complex metabolic pathways.

Tnt1 transposition events are induced by in vitro transformation of Arabidopsis thaliana, and transposed copies integrate into genes.

Tissue culture has been shown to induce the transposition of plant transposable elements; their insertion at novel sites results in somaclonal variation. Introduction of the tobacco retrotransposon Tnt1 into Arabidopsis thaliana by co-cultivation of root explants with Agrobacterium tumefaciens induces its transposition at a high frequency, but no transposed copies are found in plants transformed by the in planta procedure. Transposition occurs in the transformed root cells or in the calli derived from them, allowing the regeneration of transformed plants with up to 26 transposed copies of Tnt1. Analysis of Tnt1 integration sites in Arabidopsis shows that the Tnt1 endonuclease does not show any cleavage-site specificity at the sequence level. The insertion sites are unlinked and distributed on all five Arabidopsis chromosomes. The fact that the majority of the integration sites are located in coding regions, and none in repeated sequences, demonstrates the potential of Tnt1 as a tool for gene tagging.

Attitudes towards mental illness in the Commonwealth of Dominica.

Little is known about the perception of mental illness in the English-speaking Caribbean. This study was conducted in 1995 to determine the attitudes, knowledge, and help-seeking practices for emotional disorders in the Commonwealth of Dominica. Two groups in Dominica were surveyed: 67 community leaders, consisting of nurses, teachers, and police officers; and 135 community members grouped into five socioeconomic strata that were collapsed to three for the analysis. All the respondents were asked to identify and suggest management of individuals with psychosis, alcoholism, depression, and childhood hyperactivity, as depicted in case vignettes. The person in the psychosis vignette was diagnosed as suffering from mental illness by 84.0% of the leaders and by 71.2% of the community members. However, in each of the three other vignettes, fewer than 30% of the respondents thought that mental illness was present. The person with alcoholism was viewed as having a serious problem by only slightly more than half of the respondents. Fewer than half of the respondents thought that the individuals with depression or hyperactivity had serious problems. The community leaders did somewhat worse in recognizing mental illness than did the community members. Respondents were most likely to refer a family member with emotional problems to a medical practitioner. In conclusion, education about mental health problems is needed in Dominica. Especially disconcerting was the lack of knowledge on mental illness among nurses, teachers, and police officers, that is, professionals directly involved in the pathway to care.

Identification and disruption of an Arabidopsis zinc finger gene controlling seed germination.

We describe here the Arabidopsis gene DAG1, encoding a zinc finger transcription factor of the Dof family, and show that it is involved in the control of seed germination. By a reverse genetics approach, we isolated an Arabidopsis mutant line with one T-DNA insertion in DAG1. Seeds from homozygous knockout dag1-1 plants do not develop dormancy and germinate also in the absence of light. Segregation analysis indicates that the effect of the mutation is maternal. Accordingly, in situ mRNA hybridizations reveal expression of DAG1 in the vascular tissue of the flower and maturing fruit but not in the seed.

The GRAS gene family in Arabidopsis: sequence characterization and basic expression analysis of the SCARECROW-LIKE genes.

Mutations at the SCARECROW (SCR) locus in Arabidopsis thaliana result in defective radial patterning in the root and shoot. The SCR gene product contains sequences which suggest that it is a transcription factor. A number of Arabidopsis Expressed Sequence Tags (ESTs) have been identified that encode gene products bearing remarkable similarity to SCR throughout their carboxyl-termini, indicating that SCR is the prototype of a novel gene family. These ESTs have been designated SCARECROW-LIKE (SCL). The gene products of the GIBBERELLIN-INSENSITIVE (GAI) and the REPRESSOR of ga1-3 (RGA) loci show high structural and sequence similarity to SCR and the SCLs. Sequence analysis of the products of the GRAS (GAI, RGA, SCR) gene family indicates that they share a variable amino-terminus and a highly conserved carboxyl-terminus that contains five recognizable motifs. The SCLs have distinct patterns of expression, but all of those analyzed show expression in the root. One of them, SCL3, has a tissue-specific pattern of expression in the root similar to SCR. The importance of the GRAS gene family in plant biology has been established by the functional analyses of SCR, GAI and RGA.

The Arabidopsis thaliana cDNAs coding for eIF4E and eIF(iso)4E are not functionally equivalent for yeast complementation and are differentially expressed during plant development.

Two cDNAs (At.EIF4E1 and At.EIF4E2) encoding, respectively, the eukaryotic initiation factors eIF4E and eIF(iso)4E of Arabidopsis thaliana were isolated by complementation of a Saccharomyces cerevisiae conditional mutant. The deduced amino acid sequences of the proteins are homologous to those from monocotyledonous plants, yeast and mammals. The corresponding genes were identified in YAC clones mapping to chromosome IV (At.EIF4E1) and to chromosome V (At.EIF4E2). The yeast strain complemented by At.EIF4E2 grew poorly compared with an isogenic strain expressing At.EIF4E1. Northern and in situ hybridization analysis show that both Arabidopsis At.EIF4E1 and At.EIF4E2 mRNAs are differentially accumulated in plant tissues. The At.EIF4E1 mRNA is expressed in all tissues except in the cells of the specialization zone of the roots; the At.EIF4E2 mRNA is particularly abundant in floral organs and in young developing tissues. This work further demonstrates an association between a high level of EIF4E mRNAs and cell proliferation and suggests that the plant eIF4E isoforms may have distinct functions in cell development and metabolism.

A YAC contig map of Arabidopsis thaliana chromosome 3.

We have constructed a YAC contig map of Arabidopsis thaliana chromosome 3. From an estimated total size of 25 Mb, about 21 Mb were covered by 148 clones arranged into nine YAC contigs, which represented most of the low-copy regions of the chromosome. YAC clones were anchored with 259 molecular markers, including 111 for which linkage information was previously available. Most of the genetic map was included in the YAC coverage, and more than 60% of the genetic markers from the reference recombinant inbred line map were anchored, giving a high level of integration between the genetic and physical maps. The submetacentric structure of the chromosome was confirmed by physical data; 3R (the top arm of the linkage map) was about 12 Mb, and 3L (the bottom arm of the linkage map) was about 9 Mb. This YAC physical map will aid in chromosome walking experiments and provide a framework for large-scale DNA sequencing of chromosome 3.

Major chromosomal rearrangements induced by T-DNA transformation in Arabidopsis.

We show that major chromosomal rearrangements can occur upon T-DNA transformation of Arabidopsis thaliana. In the ACL4 line, two T-DNA insertion loci were found; one is a tandem T-DNA insert in a head-to-head orientation, and the other is a truncated insert with only the left part of the T-region. The four flanking DNA regions were isolated and located on the Arabidopsis chromosomes; for both inserts, one side of the T-DNA maps to chromosome 2, whereas the other side maps to chromosome 3. Both chromosome 3 flanking regions map to the same location, despite a 1.4-kb deletion at this point, whereas chromosome 2 flanking regions are located 40 cM apart on the bottom arm of chromosome 2. These results strongly suggest a reciprocal translocation between chromosomes 2 and 3, with the breakpoints located at the T-DNA insertion sites. The interchanged fragments roughly correspond to the 20-cM distal ends of both chromosomes. Moreover, a large inversion, spanning 40 cM on the genetic map, occurs on the bottom arm of chromosome 2. This was confirmed by genetic analyses that demonstrated a strong reduction of recombination in the inverted region. Models for T-DNA integration and the consequences for T-DNA tagging are discussed in light of these results.

Molecular analysis of cellulose biosynthesis in Arabidopsis.

Cellulose, an abundant, crystalline polysaccharide, is central to plant morphogenesis and to many industries. Chemical and ultrastructural analyses together with map-based cloning indicate that the RSW1 locus of Arabidopsis encodes the catalytic subunit of cellulose synthase. The cloned gene complements the rsw1 mutant whose temperature-sensitive allele is changed in one amino acid. The mutant allele causes a specific reduction in cellulose synthesis, accumulation of noncrystalline beta-1,4-glucan, disassembly of cellulose synthase, and widespread morphological abnormalities. Microfibril crystallization may require proper assembly of the RSW1 gene product into synthase complexes whereas glucan biosynthesis per se does not.

A physical map of chromosome 2 of Arabidopsis thaliana.

A yeast artificial chromosome (YAC) physical map of chromosome 2 of Arabidopsis thaliana has been constructed by hybridization of 69 DNA markers and 61 YAC end probes to gridded arrays of YAC clones. Thirty-four YACs in four contigs define the chromosome. Complete closure of the map was not attained because some regions of the chromosome were repetitive or were not represented in the YAC library. Based on the sizes of the YACs and their coverage of the chromosome, the length of chromosome 2 is estimated to be at least 18 Mb. These data provide the means for immediately identifying the YACs containing a genetic locus mapped on Arabidopsis chromosome 2.

Multiple regions of a divergent promoter control the expression of the Agrobacterium rhizogenes aux1 and aux2 plant oncogenes.

The two auxin biosynthesis genes, aux1 and aux2 of Agrobacterium rhizogenes strain A4, are located on opposite DNA strands with a short integenic region (394 bp) between their coding sequences. A functional analysis of this divergent promoter is presented. The transcription initiation sites of the two aux genes were determined and regions important for promoter activity were identified by deletion and transient expression analyses in tobacco protoplasts. The promoter activity of the aux intergenic region was demonstrated. A strong enhancer element contained within an 84 bp promoter fragment was identified. Far upstream regions were shown to have negative effects on the promoter activity of the short intergenic region. Interactions between positive elements in the intergenic region and negative effects of the upstream sequences may be the basis of strict control of the auxin biosynthesis necessary for the induction and maintenance of hairy root growth.

Selection for spontaneous tomato haploids using a conditional lethal marker.

We describe a method for the isolation of spontaneous haploid tomato plants from greenhousegrown seedlings obtained from crosses involving a transgenic parental line in which a counter-selectionable chimeric gene has been introduced. Transgenic seeds transformed with the aux2 gene, a gene of Agrobacterium rhizogenes that transforms naphthalene acetamide (NAM) into naphthalene acetic acid (NAA), did not develop roots in the presence of NAM, whereas wildtype tomato seeds developed a normal rooting system in its presence. Transgenic plants homozygous for aux2 (cv 'UC82b') were used to pollinate male-sterile (ms322) tomato plants (cv 'Apedice'). Using NAM as a toxic substrate to kill heterozygous diploid plants carrying aux2, we selected for three maternal haploid plants resulting from the development of the female nucleus without fertilization. Maternal haploid selection using the aux2 marker was less efficient than the visual screening of haploid plants displaying recessive morphological markers of the female parent, but provided evidence for the feasibility of haploid selection in species for which no morphological markers are available.

[Changes in Maghrebian and Portuguese family structure in France]. / Evolution des structures familiales chez les Maghrebins et les Portugais de France.

PIP: The author examines family formation in France by immigrant groups from northern Africa and Portugal. The influence of Western culture on traditional patriarchical societies is noted. (SUMMARY IN ENG AND SPA)^ieng

The TR-DNA region carrying the auxin synthesis genes of the Agrobacterium rhizogenes agropine-type plasmid pRiA4: nucleotide sequence analysis and introduction into tobacco plants.

We have determined the nucleotide sequence of a 6-kilobase fragment of the Agrobacterium rhizogenes plasmid pRiA4 TR-region that carries genes (aux1 and aux2) responsible for auxin biosynthesis in transformed plant cells. Sequence analysis revealed two open reading frames corresponding to proteins of 749 amino acids for the aux1 gene and 466 amino acids for the aux2 gene. We observed significant similarity between the amino acid sequences deduced from the pRiA4 aux genes and those of the auxin biosynthesis genes of A. tumefaciens octopine-type Ti plasmids, the iaaM and iaaH genes of Pseudomonas savastanoi, and different genes of the pRiA4 TL-region; however, the 5'-flanking regions of the pRi and pTi auxin biosynthesis genes were found to be completely different. Transgenic tobacco plants containing this entire 6-kilobase fragment of the pRiA4 TR-region have been obtained. Regenerated plants are phenotypically normal. The aux1 gene is not or is very weakly expressed in these plants, but expression of the aux2 gene leads to a modified root phenotype when plants are grown on medium containing an auxin precursor (naphthalene acetamide).