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Journal of Clinical Microbiology, January 2000, p. 227-235, Vol. 38, No. 1
Departamento de Microbiologia, Imunologia e
Parasitologia, Escola Paulista de Medicina, Universidade Federal de
São Paulo, São Paulo S.P. 04023-062, Brazil
Received 19 July 1999/Returned for modification 27 August
1999/Accepted 1 October 1999
We tested whether comparative sequence analysis of the
mitochondrion-encoded cytochrome c oxidase subunit 2 gene
(COX2) could be used to distinguish intraspecific variants
of Candida glabrata. Mitochondrial genes are suitable for
investigation of close phylogenetic relationships because they evolve
much faster than nuclear genes, which in general exhibit very limited
intraspecific variation. For this survey we used 11 clinical isolates
of C. glabrata from three different geographical locations
in Brazil, 10 isolates from one location in the United States, 1 American Type Culture Collection strain as an internal control, and the
published sequence of strain CBS 138. The complete coding region of
COX2 was amplified from total cellular DNA, and both
strands were sequenced twice for each strain. These sequences were
aligned with published sequences from other fungi, and the numbers of
substitutions and phylogenetic relationships were determined. Typing of
these strains was done by using 17 substitutions, with 8 being
nonsynonymous and 9 being synonymous. Also, cDNAs made from purified
mitochondrial polyadenylated RNA were sequenced to confirm that our
sequences correspond to the expressed copies and not nuclear
pseudogenes and that a frameshift mutation exists in the 3' end of the
coding region (position 673) relative to the Saccharomyces
cerevisiae sequence and the previously published C. glabrata sequence. We estimated the average evolutionary rate of
COX2 to be 11.4% sequence divergence/108 years
and that phylogenetic relationships of yeasts based on these sequences
are consistent with rRNA sequence data. Our analysis of
COX2 sequences enables typing of C. glabrata
strains based on 13 haplotypes and suggests that positions 51 and 519 indicate a geographical polymorphism that discriminates strains
isolated in the United States and strains isolated in Brazil. This
provides for the first time a means of typing of Candida
strains that cause infections by use of direct sequence comparisons and
the associated divergence estimates.
0095-1137/0/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
Typing of Candida glabrata in Clinical
Isolates by Comparative Sequence Analysis of the Cytochrome
c Oxidase Subunit 2 Gene Distinguishes Two Clusters of
Strains Associated with Geographical Sequence Polymorphisms
*
Corresponding author. Mailing address: Disciplina de
Microbiologia, Departamento de Microbiologia, Imunologia e
Parasitologia, Escola Paulista de Medicina, Universidade Federal de
São Paulo, Rua Botucatu, 862, 3° andar, CEP 04023-062, São Paulo, S.P., Brazil, Phone: (55) (11)5084-3213. Fax: (55)
(11)571-6504. E-mail: marcelo.dmip{at}epm.br.
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