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Teresa Ribeiro

Publications and source records attributed to Teresa Ribeiro.

4 recordsLinked to original sources
PubMed2005

Transplants of aquatic mosses as biomonitors of metals released by a mine effluent.

Transplants of the aquatic moss Fontinalis antipyretica Hedw. were used to assess the contamination of an industrial effluent discharge on a river located in south Portugal. The sampling program was run for 2 years, using a newly developed transplant device in ten stations, and the elements analysed were Cu, Zn, Pb, Fe, Ni, Ca, K, and Mg. An increase of water contamination by Cu, Zn was detected, and to a lesser extent, Pb. The increase was verified in the extra and intracellular moss fraction, especially for soluble Cu in the first 4 km after the discharge point, and also for particulate metal at the first station after the discharge. The effects of metal contamination could be related to changes in the intracellular concentrations of Mg, indicating possible stress effects.

Biodegradation, Environmental↗
PubMed2005

Molecular and cytological characterization of genomic variability in hexaploid wheat 'Lindström'.

'Lindström' wheat (AABBDD+rye B chromosomes) was used to study the effects of alien chromatin introgressed into a wheat genetic background, subjecting the wheat genome to a new and transient allopolyploidisation episode. Using this experimental material, we have previously demonstrated that no large-scale chromosomal translocations occurred as a result of the genomic constitution of the addition line. However, we have shown that the presence of a number of rye B chromosomes is associated with changes in the interphase organization and expression patterns of wheat rDNA loci. We have now extended our studies to focus on a further characterization of 'Lindström' 5S rDNA loci and also on high molecular weight glutenin subunit (HMW-GS) patterns. In the process, we have uncovered an unusually large variant of the 5S rDNA locus on wheat chromosome 1B (not to be confused with rye B chromosomes) and 2 novel HMW glutenin y-type alleles. These changes are not directly related to variation in rye B chromosome number in the present material, but the fact that a new, and still segregating, 1Dy HMW-GS gene was identified indicates a recent timescale for its origin. Strikingly, the 'Lindström' 5S rDNA 1B locus integrates a unit sharing 94% homology with a rye 5S rDNA sequence, suggesting the possibility that the wheat locus was colonized by highly homologous rye sequences during the breeding of 'Lindström', when the rye and wheat genomes were together, albeit briefly, in the same nucleus.

Base Sequence↗
PubMed2004

Evidence for 'cross-talk' between A and B chromosomes of rye.

Spontaneous DNA insertions from supernumerary B chromosomes (Bs) into the standard A chromosome complement were detected in rye (Secale cereale L.), using fluorescent in situ hybridization (FISH) analysis with the D1100 B-specific sequence probe. The insertions were seen in individuals derived from plants possessing deleted Bs, characterized in this study by not having the B-specific sequences that are normally found at the distal part of the long arm of the standard rye B. This result supports the case for the spontaneous introgression of B-specific DNA into the A chromosome genome, and it indicates that 'cross-talking' between A and B chromosomes may occur in wild populations.

Chromosomes, Plant↗