Colette Tremblay | Université Laval (original) (raw)
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Papers by Colette Tremblay
Canadian Journal of Botany, 1984
Current Genetics, Sep 1, 1994
Journal of Neuroscience Research, 1989
Canadian Journal of Botany, 1984
Experiments were undertaken to compare three strains of tobacco mosaic virus (TMV) belonging to t... more Experiments were undertaken to compare three strains of tobacco mosaic virus (TMV) belonging to the tobacco group 1 of the tobamoviruses. Although the U1, U4, and U7 strains of TMV differ significantly in virulence, it was shown that these strains are very closely related. No difference was detected in the major spots of the coat protein tryptic maps and the virions from the three strains shared the same electrophoretic mobility in agarose gels with different buffer systems. The RNA fingerprints of U1 and U7 were indistinguishable and the largest T1 omega fragments of the three strains were identical in size. However, the avirulent U4 RNA fingerprint exhibited a single spot mobility difference from the U1 and U7 RNA fingerprints. This spot corresponded to the T1 phi fragment. This unique fragment is located in the so-called l2 gene between nucleotides 976 and 992 from the 3′ end. This suggests and extends the proposal that the l2 gene is most probably implicated as a factor in the c...
Journal of Experimental Zoology, 1992
Journal of Experimental Zoology, 1992
Incorporation of radioactive sulfate to hatched veliger larvae of the gastropod muricid Concholep... more Incorporation of radioactive sulfate to hatched veliger larvae of the gastropod muricid Concholepas concholepas indicated that over 87% of the sulfated macromolecules were found in the detergent insoluble fraction, rich in extracellular matrix (ECM) components. The sulfated material was solubilized with guanidine salt followed by urea dialysis and fractionated by DEAE-Sephacel chromatography. Three sulfated compounds eluting at 0.7, 1.1, and 3.0 M NaCl, called peaks I, II, and III, respectively, were obtained. The sulfated compound present in peak I was degraded by pronase or sodium alkaline treatment to a small sulfated resistant material, suggesting the presence of a proteoglycan (PG). Filtration analysis on Sephacryl S-500 and SDS-PAGE of the intact PG indicates that it has a high molecular weight (360,000 to over 1 × 106). Monoclonal antibodies (mAb) against this PG were produced. The specificity of one mAb, the 6H2, was demonstrated by size chromatography and ELISA analysis. The epitope recognized by this mAb seems to be present in the core protein of the PG. Both the extent of sulfation and the presence of different sulfated species of PGs were evaluated during the development of this mollusc. A twelvefold increase in the incorporation of sulfate to PGs per milligram of protein was found in veliger larvae compared to blastula-glastula stages. This change correlated well with the differential expression of the sulfated PG present in peak I. Biochemical and immunological analysis indicate that high levels of this PG are found in veliger and trocophore larvae in comparison with blastula-gastrula and early juveniles. These results indicate that a high molecular weight PG probably of the ECM is differentially expressed during the development of the gastropod Concholepas concholepas. © 1992 Wiley-Liss, Inc.
Botany-botanique, 1984
ABSTRACT
Current Genetics, 1991
A full-length 1010-bp cDNA clone from Chlamydomonas moewusii coding for the precursor of a chloro... more A full-length 1010-bp cDNA clone from Chlamydomonas moewusii coding for the precursor of a chlorophyll a/b-binding protein (CAB) was characterized. Northern analysis shows hybridization to a single 1150-base light-stimulated mRNA. Complementary hybrid-selected mRNAs were translated in vitro; SDS-PAGE indicates the synthesis of three polypeptides of 25, 27 and 28 kDa. Comparison of the deduced polypeptide sequence with other published CABs reveals greater similarity with PSII-associated proteins but, as with other algal CABs, our sequence does not meet established criteria for inclusion into either type I or type II, so branching of CABs into two types seems to have occurred after the divergence between algae and land plants.
Current Genetics, 1994
We have cloned and sequenced a Chlamydomonas moewusii chloroplastic DNA fragment that includes a ... more We have cloned and sequenced a Chlamydomonas moewusii chloroplastic DNA fragment that includes a 563 amino-acid open reading frame (ORF563, chlB) presenting 89% amino-acid homology with ORF513 from Marchantia polymorpha. It is also homologous to ORF510 from Pinus thumbergii but includes two insertions absent in both M. polymorpha and P. thunbergii. The derived polypeptide is 54% similar to the product of bchB from Rhodobacter capsulatus, identified as one subunit of a light-independent NADH-protochlorophyllide reductase. We also isolated and sequenced an homologous chloroplastic gene from the gymnosperm Ginkgo biloba. Northern hybridizations performed on RNA isolated from synchronized Chlamydomonas eugametos cells showed higher expression between the tenth hour of light and the eighth hour of darkness, peaking during the first 2 h of darkness.
Journal of Molecular Evolution, 1997
The analysis of nuclear-encoded chitinase sequences from various angiosperms has allowed the cate... more The analysis of nuclear-encoded chitinase sequences from various angiosperms has allowed the categorization of the chitinases into discrete classes. Nucleotide sequences of their catalytic domains were compared in this study to investigate the evolutionary relationships between chitinase classes. The functionally distinct class III chitinases appear to be more closely related to fungal enzymes involved in morphogenesis than to other plant chitinases. The ordering of other plant chitinases into additional classes mainly relied on the presence of auxiliary domains—namely, a chitin-binding domain and a carboxy-terminal extension—flanking the main catalytic domain. The results of our phylogenetic analyses showed that classes I and IV form discrete and well-supported monophyletic groups derived from a common ancestral sequence that predates the divergence of dicots and monocots. In contrast, other sequences included in classes I* and II, lacking one or both types of auxiliary domains, were nested within class I sequences, indicating that they have a polyphyletic origin. According to phylogenetic analyses and the calculation of evolutionary rates, these chitinases probably arose from different class I lineages by relatively recent deletion events. The occurrence of such evolutionary trends in cultivated plants and their potential involvement in host–pathogen interactions are discussed.
Canadian Journal of Botany, 1984
Current Genetics, Sep 1, 1994
Journal of Neuroscience Research, 1989
Canadian Journal of Botany, 1984
Experiments were undertaken to compare three strains of tobacco mosaic virus (TMV) belonging to t... more Experiments were undertaken to compare three strains of tobacco mosaic virus (TMV) belonging to the tobacco group 1 of the tobamoviruses. Although the U1, U4, and U7 strains of TMV differ significantly in virulence, it was shown that these strains are very closely related. No difference was detected in the major spots of the coat protein tryptic maps and the virions from the three strains shared the same electrophoretic mobility in agarose gels with different buffer systems. The RNA fingerprints of U1 and U7 were indistinguishable and the largest T1 omega fragments of the three strains were identical in size. However, the avirulent U4 RNA fingerprint exhibited a single spot mobility difference from the U1 and U7 RNA fingerprints. This spot corresponded to the T1 phi fragment. This unique fragment is located in the so-called l2 gene between nucleotides 976 and 992 from the 3′ end. This suggests and extends the proposal that the l2 gene is most probably implicated as a factor in the c...
Journal of Experimental Zoology, 1992
Journal of Experimental Zoology, 1992
Incorporation of radioactive sulfate to hatched veliger larvae of the gastropod muricid Concholep... more Incorporation of radioactive sulfate to hatched veliger larvae of the gastropod muricid Concholepas concholepas indicated that over 87% of the sulfated macromolecules were found in the detergent insoluble fraction, rich in extracellular matrix (ECM) components. The sulfated material was solubilized with guanidine salt followed by urea dialysis and fractionated by DEAE-Sephacel chromatography. Three sulfated compounds eluting at 0.7, 1.1, and 3.0 M NaCl, called peaks I, II, and III, respectively, were obtained. The sulfated compound present in peak I was degraded by pronase or sodium alkaline treatment to a small sulfated resistant material, suggesting the presence of a proteoglycan (PG). Filtration analysis on Sephacryl S-500 and SDS-PAGE of the intact PG indicates that it has a high molecular weight (360,000 to over 1 × 106). Monoclonal antibodies (mAb) against this PG were produced. The specificity of one mAb, the 6H2, was demonstrated by size chromatography and ELISA analysis. The epitope recognized by this mAb seems to be present in the core protein of the PG. Both the extent of sulfation and the presence of different sulfated species of PGs were evaluated during the development of this mollusc. A twelvefold increase in the incorporation of sulfate to PGs per milligram of protein was found in veliger larvae compared to blastula-glastula stages. This change correlated well with the differential expression of the sulfated PG present in peak I. Biochemical and immunological analysis indicate that high levels of this PG are found in veliger and trocophore larvae in comparison with blastula-gastrula and early juveniles. These results indicate that a high molecular weight PG probably of the ECM is differentially expressed during the development of the gastropod Concholepas concholepas. © 1992 Wiley-Liss, Inc.
Botany-botanique, 1984
ABSTRACT
Current Genetics, 1991
A full-length 1010-bp cDNA clone from Chlamydomonas moewusii coding for the precursor of a chloro... more A full-length 1010-bp cDNA clone from Chlamydomonas moewusii coding for the precursor of a chlorophyll a/b-binding protein (CAB) was characterized. Northern analysis shows hybridization to a single 1150-base light-stimulated mRNA. Complementary hybrid-selected mRNAs were translated in vitro; SDS-PAGE indicates the synthesis of three polypeptides of 25, 27 and 28 kDa. Comparison of the deduced polypeptide sequence with other published CABs reveals greater similarity with PSII-associated proteins but, as with other algal CABs, our sequence does not meet established criteria for inclusion into either type I or type II, so branching of CABs into two types seems to have occurred after the divergence between algae and land plants.
Current Genetics, 1994
We have cloned and sequenced a Chlamydomonas moewusii chloroplastic DNA fragment that includes a ... more We have cloned and sequenced a Chlamydomonas moewusii chloroplastic DNA fragment that includes a 563 amino-acid open reading frame (ORF563, chlB) presenting 89% amino-acid homology with ORF513 from Marchantia polymorpha. It is also homologous to ORF510 from Pinus thumbergii but includes two insertions absent in both M. polymorpha and P. thunbergii. The derived polypeptide is 54% similar to the product of bchB from Rhodobacter capsulatus, identified as one subunit of a light-independent NADH-protochlorophyllide reductase. We also isolated and sequenced an homologous chloroplastic gene from the gymnosperm Ginkgo biloba. Northern hybridizations performed on RNA isolated from synchronized Chlamydomonas eugametos cells showed higher expression between the tenth hour of light and the eighth hour of darkness, peaking during the first 2 h of darkness.
Journal of Molecular Evolution, 1997
The analysis of nuclear-encoded chitinase sequences from various angiosperms has allowed the cate... more The analysis of nuclear-encoded chitinase sequences from various angiosperms has allowed the categorization of the chitinases into discrete classes. Nucleotide sequences of their catalytic domains were compared in this study to investigate the evolutionary relationships between chitinase classes. The functionally distinct class III chitinases appear to be more closely related to fungal enzymes involved in morphogenesis than to other plant chitinases. The ordering of other plant chitinases into additional classes mainly relied on the presence of auxiliary domains—namely, a chitin-binding domain and a carboxy-terminal extension—flanking the main catalytic domain. The results of our phylogenetic analyses showed that classes I and IV form discrete and well-supported monophyletic groups derived from a common ancestral sequence that predates the divergence of dicots and monocots. In contrast, other sequences included in classes I* and II, lacking one or both types of auxiliary domains, were nested within class I sequences, indicating that they have a polyphyletic origin. According to phylogenetic analyses and the calculation of evolutionary rates, these chitinases probably arose from different class I lineages by relatively recent deletion events. The occurrence of such evolutionary trends in cultivated plants and their potential involvement in host–pathogen interactions are discussed.