Biomedical subjects

D A Ducasse

Publications and source records attributed to D A Ducasse.

4 recordsLinked to original sources

PubMed2001

Immunocapture reverse transcription-polymerase chain reaction combined with nested PCR greatly increases the detection of Prunus necrotic ring spot virus in the peach.

A detection system based on nested PCR after IC-RT-PCR (IC-RT-PCR-Nested PCR) was developed to improve indexing of Prunus necrotic ringspot virus in peach trees. Inhibitory effects and inconsistencies of the standard IC-RT-PCR were overcome by this approach. IC-RT-PCR-Nested PCR improved detection by three orders of magnitude compared with DAS-ELISA for the detection of PNRSV in leaves. Several different tissues were evaluated and equally consistent results were observed. The main advantages of the method are its consistency, high sensitivity and easy application in quarantine programs.

Bromoviridae↗

PubMed1997

Sequencing and characterization of the coat protein and 3' non-coding region of a new sweet potato potyvirus.

A cDNA library was constructed from viral genomic RNA purified from sweet potato plants affected by "Sweet Potato Chlorotic Dwarf disease" in an attempt to clarify the etiology of this viral complex in Argentina. By sequence analysis, some of the obtained clones were found to belong to sweet potato feathery mottle potyvirus (SPFMV), to a closterovirus and to a new potyvirus. A cDNA clone of 1,103 bp representing the coat protein cistron and 3' non-coding region of the newly identified potyvirus was further characterized. The sequence contained an ORF of 855 nucleotides with a coding capacity of 285 amino acids, followed by a 3' untranslated tail of 248 nucleotides. The core and C-terminal regions have sequences well conserved among potyviruses. Furthermore, amino acid sequence comparisons of the capsid protein with those of other described potyviruses showed 63% homology with SPFMV, 68 to 70% with two different isolates of sweet potato latent potyvirus (SPLV), 57% with sweet potato G potyvirus (SPGV) and 73% with potato virus Y (PVY). These data allowed us to propose the inclusion of this virus as a new member of the family Potyviridae, genus Potyvirus with the designation sweet potato mild speckling potyvirus (SPMSV).

Amino Acid Sequence↗

PubMed1995

Gene I mutants of peanut chlorotic streak virus, a caulimovirus, replicate in plants but do not move from cell to cell.

Gene I of peanut chlorotic streak virus (PCISV), a caulimovirus, is homologous to gene I of other caulimoviruses and may encode a protein for virus movement. To evaluate the function of gene I, several mutations were created in this gene of an infectious, partially redundant clone of PCISV. Constructs with an in-frame deletion and a single amino acid substitution in gene I were not infectious. To test for replication of these mutants in primarily infected cells, an immunosorbent PCR technique was devised. Virus particles formed by mutants in plants were recovered by binding to antivirus antibodies on a solid matrix and DNase treated to discriminate against residual inoculum, and DNA of trapped virions was subjected to PCR amplification. Gene I mutants were shown to direct formation of encapsidated DNA as revealed by a PCR product. Control gene V mutants (reverse transcriptase essential for replication) did not yield a PCR product. Quantitative PCR allowed estimation of the proportion of cells initially infected by gene I mutants and the amount of extractable virus per cell. It is concluded that PCISV gene I encodes a movement protein and that the immunoselection-PCR technique is useful in studying subliminal virus infection in plants.

Amino Acid Sequence↗

PubMedDate not supplied

A triply avulsed tooth.

Canada has a rich hockey tradition. Accordingly, Canadian dentists are well acquainted with tooth avulsion, although the emergence as the mouth guard as an essential component of protective sports equipment has reduced its incidence. Practitioners occasionally examine patients who have lost teeth as a result of accidents. In this unusual case, a patient's tooth was removed 3 times in 12 hours.

Adult↗