Sequence and analysis of chromosome 3 of the plant Arabidopsis thaliana.

Arabidopsis thaliana is an important model system for plant biologists. In 1996 an international collaboration (the Arabidopsis Genome Initiative) was formed to sequence the whole genome of Arabidopsis and in 1999 the sequence of the first two chromosomes was reported. The sequence of the last three chromosomes and an analysis of the whole genome are reported in this issue. Here we present the sequence of chromosome 3, organized into four sequence segments (contigs). The two largest (13.5 and 9.2 Mb) correspond to the top (long) and the bottom (short) arms of chromosome 3, and the two small contigs are located in the genetically defined centromere. This chromosome encodes 5,220 of the roughly 25,500 predicted protein-coding genes in the genome. About 20% of the predicted proteins have significant homology to proteins in eukaryotic genomes for which the complete sequence is available, pointing to important conserved cellular functions among eukaryotes.

The DNA sequence of human chromosome 21.

Chromosome 21 is the smallest human autosome. An extra copy of chromosome 21 causes Down syndrome, the most frequent genetic cause of significant mental retardation, which affects up to 1 in 700 live births. Several anonymous loci for monogenic disorders and predispositions for common complex disorders have also been mapped to this chromosome, and loss of heterozygosity has been observed in regions associated with solid tumours. Here we report the sequence and gene catalogue of the long arm of chromosome 21. We have sequenced 33,546,361 base pairs (bp) of DNA with very high accuracy, the largest contig being 25,491,867 bp. Only three small clone gaps and seven sequencing gaps remain, comprising about 100 kilobases. Thus, we achieved 99.7% coverage of 21q. We also sequenced 281,116 bp from the short arm. The structural features identified include duplications that are probably involved in chromosomal abnormalities and repeat structures in the telomeric and pericentromeric regions. Analysis of the chromosome revealed 127 known genes, 98 predicted genes and 59 pseudogenes.

Effects of emotion-related surface similarity in analogical problem solving.

In analogical problem solving, a source problem with a known solution is used to solve a target problem. The present study deals with one possible condition influencing the search for possible source problems (i.e., with similarities between source and target problems in the emotional connotation of the problem cover stories). Subjects were given six source problems-distractors as well as target-relevant problems-that were varied with respect to the emotional valence of the cover stories. Then one group of subjects (n = 32) was given a pleasant target problem, while the other group (n = 31) received an unpleasant target problem. Except for emotional valence the two target problems were identical. Subjects preferred those target-relevant source problems that were emotionally congruent with the target problem. The findings are interpreted within network theories of long-term memory, introducing emotional markers or emotion-concept nodes to represent the emotional connotation of the represented units. By controlling subjects' mood change after reading the (un)pleasant target-problem cover story, it could be ruled out that the observed results were due to a mood congruity effect of the type described by Bower (1981).

[Anal tuberculosis. Report of a case]. / Tuberculosis anal. Caso clínico.

We report a 70 years old man presenting with malaise, anal pain and progressive defecation difficulty, with a decrease in stool caliber. The patient had no contact or past history of tuberculosis. On physical examination, there was an ulcerated anal lesion with purulent discharge, that produced an anal stenosis. The patient had an erythrocyte sedimentation rate of 108 mm/h, images of active tuberculosis in both apical pulmonary lobes and a chronic tuberculous inflammation with caseation and epithelioid tubercles was observed in a biopsy of the anal lesion. Treatment with antituberculous drugs produced a categorical remission of anal lesions and after five months of therapy the patient is well.

Image analysis techniques for automatic evaluation of two-dimensional electrophoresis.

Techniques for automatic analysis of two-dimensional electrophoresis gels by computer-aided image analysis are described. Original gels or photographic films are scanned using a laser scanner and the files are transferred to a microcomputer. The program package first performs a compression and preevaluation of the files. Spot identification and quantification is performed by the chain code algorithm after appropriate zooming and cutting. Labeling facilitates spot identification and quantification in numerical and graphical (pseudocolor) representation on peripheral devices for camera ready output. Interpolation between measured basepoints is performed by cubic spline algorithms which are automatically switched on and off, depending on the need by the program. High speed analysis and graphic representation is achieved using fast Assembler language routines rather than high level languages. One-dimensional gels can be analyzed using the same software. Spot matching between parallel two-dimensional gels has not yet been implemented.