INVESTIGADORES
SANCHEZ PUERTA Maria virginia
artículos
Título:
Pseudulvella americana (Snow) Wille belongs to the order Chaetopeltidales (Class Chlorophyceae), evidence from ultrastructure and SSU rDNA sequence data
Autor/es:
SÁNCHEZ PUERTA, M. V., P.I. LEONARDI, C.J OKELLY & E.J. CÁCERES
Revista:
JOURNAL OF PHYCOLOGY
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Año: 2006 vol. 42 p. 943 - 950
ISSN:
0022-3646
Resumen:
The genus Pseudulvella Wille 1909 includes epiphytic, freshwater, or
marine disk-shaped green microalgae that form quadriflagellate zoospores. No ultrastructural
or molecular studies have been conducted on the genus, and its evolutionary
relationships remain unclear. The purpose of the present study is to describe
the life history, ultrastructural features, and phylogenetic affiliations of Pseudulvella
americana (Snow) Wille,
the type species of the genus. Thalli of this microalga were prostrate and composed
of radiating branched filaments that coalesced to form a disk. Vegetative cells
had a pyrenoid encircled by starch plates and traversed by one or two
convoluted cytoplasmic channels. They hadwell-defined cell walls without
plasmodesmata. Asexual reproduction was by means of tetraflagellate zoospores
formed in numbers of two to eight from central cells of the thallus. The
flagellar apparatus of zoospores was cruciate, with four basal bodies and four
microtubular roots. The paired basal bodies lay directly opposite (DO) one another.
The microtubular root system had a 5-2-5-2 alternation pattern, where the s
roots contained five microtubules in a four-over-one configuration. A tetralobate
non-striated distal fiber connected all four basal bodies. A wedge-shaped
proximal sheath subtended each of the basal bodies. The ultrastructural features
of the zoospores were those of members of the order Chaetopeltidales.
Phylogenetic analyses based on SSU rDNA placed P. americana sister to Chaetopeltis orbicularis in a well-supported Chaetopeltidales clade.
Such a combination of features confirmed that this alga is a member ofthe order
Chaetopeltidales.