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Infection and Immunity, August 1999, p. 4298-4302, Vol. 67, No. 8
Department of Microbiology, The University of
Texas Health Science Center at San Antonio, San Antonio, Texas
Received 4 March 1999/Returned for modification 5 May 1999/Accepted 17 May 1999
Trichomonas vaginalis infected with a double-stranded
RNA virus undergoes phenotypic variation on the basis of surface versus cytoplasmic expression of the immunogenic protein P270. Examination of
batch cultures by flow cytofluorometry with monoclonal antibody (MAb)
to P270 yields both fluorescent and nonfluorescent trichomonads. Greater numbers and intensity of fluorescent organisms with surface P270 reactive with MAb were evident in parasites grown in medium depleted of iron. Placement of iron-limited organisms in medium supplemented with iron gave increased numbers of nonfluorescent trichomonads. Purified subpopulations of trichomonads with and without
surface P270 obtained by fluorescence-activated cell sorting reverted
to nonfluorescent and fluorescent phenotypes when placed in high- and
low-iron media, respectively. No similar regulation by iron of P270 was
evident among virus-negative T. vaginalis isolates or
virus-negative progeny trichomonads derived from virus-infected isolates. Equal amounts of P270 were detectable by MAb on immunoblots of total proteins from identical numbers of parasites grown in low- and
high-iron media. Finally, P270 was found to be highly phosphorylated in
high-iron parasites. Iron, therefore, plays a role in modulating
surface localization of P270 in virus-harboring parasites.
0019-9567/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.
Iron Modulates Phenotypic Variation and Phosphorylation of P270
in Double-Stranded RNA Virus-Infected Trichomonas
vaginalis
*
Mailing address: Department of Microbiology, UTHSCSA,
7703 Floyd Curl Dr., San Antonio, TX 78284-7758. Phone: (210) 567-6828. Fax: (210) 567-6612. E-mail: alderete{at}uthscsa.edu.
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