Rezumatul tezei de doctorat - USAMV Cluj-Napoca

pellets were filtred, washed with distilled water and maintained at -20°C until DNA was
extracted (adapted method after Leclerc and al., 2000).
We mention the fact that this procedure was applied to fungi samples obtained from
the water collected in June 2009, including 138 samples, whereby 69 samples on solid-liquid
medium combination, Potato Dextrose Agar (PDA)- Potato Dextrose Broth (PDB), and the
other 69 samples on solid-liquid Sabouraud 2% Glucose Agar (SGA) - Sabouraud Dextrose
Broth (SDB).
I.3.3.3. Antibiotics used in the experiment
For preventing the bacterial development and contamination, in the fungi culture
media there are used more types of antibiotics (Lategan and al., 2003, 2004). In our
experience, we opted for Penicillin G potassium salt (Sigma). We used the working
concentration of de 100 mg L - Penicillin G potassium salt, on both solid and liquid media.
I.3.4. Morphological characterization of Saprolegnia strains
For the morphological characterization of Saprolegnia strains, developed on culture
media, we analyzed the 69 samples with the following aspects: the hyphal type specific to
Saprolegnia genus, the asexual reproduction (flagella presence on primary zoospores) and
the formation of sexual structures (antheridia and oogonia).
Fungal strains collected from each fishpond, at 72 hours of growing on PDA solid
medium, were inoculated in 9 cm diameter plastic Petri dishes, on the same PDA medium, at
22ºC, 5,5 pH. Saprolegnia’s growing was periodically examined at the microscope, for 2-3
weeks, to check the developing of sexual structures. All the strains were characterized and
identified pursuant to the control keys communicated by Johnson Jr. and al., 2002 (Dieguez-
Uribeondo and al., 2007).
The microscope observations were performed for each sample from each fishpond,
after the following procedure: we isolated with a microbiological dowser a part of the colony
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