Biomedical subjects

B Overduin

Publications and source records attributed to B Overduin.

5 recordsLinked to original sources

PubMed2006

Ensembl 2006.

The Ensembl (http://www.ensembl.org/) project provides a comprehensive and integrated source of annotation of large genome sequences. Over the last year the number of genomes available from the Ensembl site has increased from 4 to 19, with the addition of the mammalian genomes of Rhesus macaque and Opossum, the chordate genome of Ciona intestinalis and the import and integration of the yeast genome. The year has also seen extensive improvements to both data analysis and presentation, with the introduction of a redesigned website, the addition of RNA gene and regulatory annotation and substantial improvements to the integration of human genome variation data.

Animals↗

PubMed1995

Inheritance and genetic mapping of resistance to Alternaria alternata f. sp. lycopersici in Lycopersicon pennellii.

The fungal pathogen Alternaria alternata f. sp. lycopersici produces AAL-toxins that function as chemical determinants of the Alternaria stem canker disease in the tomato (Lycopersicon esculentum). In resistant cultivars, the disease is controlled by the Asc locus on chromosome 3. Our aim was to characterize novel sources of resistance to the fungus and of insensitivity to the host-selective AAL-toxins. To that end, the degree of sensitivity of wild tomato species to AAL-toxins was analyzed. Of all members of the genus Lycopersicon, only L. cheesmanii was revealed to be sensitive to AAL-toxins and susceptible to fungal infection. Besides moderately insensitive responses from some species, L. pennellii and L. peruvianum were shown to be highly insensitive to AAL-toxins as well as resistant to the pathogen. Genetic analyses showed that high insensitivity to AAL-toxins from L. pennellii is inherited in tomato as a single complete dominant locus. This is in contrast to the incomplete dominance of insensitivity to AAL-toxins of L. esculentum. Subsequent classical genetics, RFLP mapping and allelic testing indicated that high insensitivity to AAL-toxins from L. pennellii is conferred by a new allele of the Asc locus.

Alternaria↗

PubMed1993

Transposition pattern of a modified Ds element in tomato.

Several aspects of transposition of an in vitro modified Ds element are described. This Ds element, designated Ds-r, is equipped with bacterial plasmid sequences and can, therefore, be rescued from the plant genome. Our results indicate that the Ds-r element has a 'late' timing of transposition from T-DNAs. This feature of the element might be advantageous for tagging experiments because it leads to independently transposed germinally transmitted elements. Furthermore, it is shown that Ds-r transposition generates clusters of insertions, indicating that 'genes to be tagged' should be located in genomic regions covered by insertions.

Base Sequence↗

PubMed1993

The Asc locus for resistance to Alternaria stem canker in tomato does not encode the enzyme aspartate carbamoyltransferase.

The fungal disease resistance locus Alternaria stem canker (Asc) in tomato has been suggested to encode the enzyme aspartate carbamoyltransferase (ACTase). To test this hypothesis a segment of the tomato ACTase gene was amplified by the polymerase chain reaction (PCR) using degenerate primers. The PCR product obtained was subsequently used to isolate an ACTase cDNA clone. Restriction fragment length polymorphism (RFLP) linkage analysis showed that the ACTase gene and the Asc locus do not cosegregate. RFLP mapping positioned the ACTase gene on chromosome 11, while the Asc locus is located on chromosome 3. These results exclude the possibility that the ACTase protein is encoded by the Asc locus.

Alternaria↗

PubMed1988

Transgenic tobacco expressing tobacco streak virus or mutated alfalfa mosaic virus coat protein does not cross-protect against alfalfa mosaic virus infection.

Transgenic tobacco plants expressing the coat protein (CP) genes of tobacco streak virus (TSV) and alfalfa mosaic virus (AIMV) were used in studies on cross-protection and genome activation. Plants expressing the TSV CP gene were highly resistant to infection with TSV nucleoproteins but were susceptible to infection with AIMV nucleoproteins. Moreover, these plants could be infected with a mixture of AIMV RNAs 1, 2, and 3 in contrast to the nontransformed control plants. This demonstrates that the endogenously produced TSV CP is able to activate the AIMV genome but does not cross-protect against this virus. Conversely, it was shown that plants expressing the AIMV CP gene did not resist TSV infection. Transgenic tobacco plants transformed with an AIMV CP gene with a frame-shift mutation in the reading frame were found to accumulate viral transcripts to a level similar to that obtained in plants expressing a wild-type AIMV CP gene. However, these plants did not produce detectable amounts of viral protein and showed no resistance to infection with AIMV nucleoproteins in contrast to transgenic plants accumulating wild-type AIMV CP. This demonstrates that it is the CP that is responsible for cross-protection in transgenic plants and not the chimeric CP mRNA.

Capsid↗