|
Synechococcus
and Prochlorococcus compose a homogenous group easily
identified and counted by flow cytometry. Picoeukaryotes group
presents a high diversity of genus and species. Their cellular
characteristics cannot be used in microscopy or flow cytometry
for their identification. The in situ TSA fish
technique is a valuable method to assess the picoeukaryote
biodiversity. The technique relies on the specific
hybridization of the nucleic acid probes to the naturally
amplified intracellular rRNA. Fluorescently labeled,
rRNA-targeted oligonucleotides probes allow an in situ
identification of individual microbial cells in their natural
habitats.
Fluorescent
probes are counted in a 0.2 filter with an epifluorecence
microscope.
Table
1:
Characteristics
and specificity of molecular probes
|
Probe
|
Sequence
(5' vers 3')
|
Specificity
|
Observations
|
References
|
|
EUK
1209R
|
GGGCATCACAGACCTG
|
The
main part of Eucaryotes
|
|
Lim
et al. 1993
|
|
CHLO01
|
GCTCCACCGCCTGGTGGTG
|
Chlorophyta,
Cryptophyta, Pavlovales
|
Some
Chlorophyta are not marked. Some Apicomplexa are marked
|
Simon
et al. 1995
|
|
CHLO02
|
|
Chlorophyta
|
|
Simon
et al. 2000
|
|
NCHLO01
|
GCTCCACTCCTGGTGGTG
|
Dinophyta,
Prymnesiophyta,
Heterocontophyta
|
Some
Chlorophyta are marked.
|
Simon
et al. 1995
|
|
PRYM02
|
GGAATACGAGTGCCCCTGAC
|
Prymnesiophyta
|
Some
species are not marked
|
Simon
et al. 2000
|
|
BOLI01
|
CAGTCTGATGAACTGCGT
|
Bolidophycées
|
|
Guillou
et al. 1999
|
|
PELA01
|
ACGTCCTTGTTCGACGCT
|
Pélagophycées
(Heteroconta)
|
|
Simon
et al. 2000
|
|
PRAS02
|
CCCXXXXXXXCCAACG
|
Clade
II of Prasinophycées
|
|
not
published
|
References
Simon,
N., L. Campbell, E. Ornolfsdottir, R. Groben, L. Guillou, M. Lange, and L. K.
Medlin. 2000. Oligonucleotide probes for the identification of three algal
groups by dot blot and fluorescent whole-cell hybridization. Journal of
Eukaryotic Microbiology 47: 76-
|
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