Rezumatul tezei de doctorat - USAMV Cluj-Napoca

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INTRODUCTION Saprolegniasis is one of the most important causes of economic losses in aquaculture, fungal infections are second only to bacterial diseases in economic importance. Fungal infections are generally restricted to chronic, steady losses. Saprolegnia infests a large number of teleosts, as: channel catfish, pike, bass, roach, carp, salmonids, sturgeon, barramundi, tilapia; being associated with tropical fish: gourami, guppy, platyfish. In Japan, there is an annual mortality rate of 50% in coho salmon (Oncorhynchus kisutch) due to Saprolegnia parasitica Coker. Fifty percent per year losses have also been reported in elver (Anguilla anguilla) culture in Japan. In Scotland, saprolegniasis causes important economic losses especially in salmon fisheries. In the southeastern of United States, major losses of 50% occur in channel catfish farming, and the economic loss of 40 million dollars. In Romania, until now, there is not a scientific estimation of the fisheries losses due to saprolegniasis. CHAPTER I EXPERIMENTAL HYPOTHESIS, RESEARCH OBJECTIVES, EXPERIMENTAL DISPOSAL, MATERIAL AND METHOD I.1. EXPERIMENTAL HYPOTHESIS AND RESEARCH OBJECTIVES The bibliographic study on fish saprolegniasis in general, and particularly on carp species, indicates the fact that in the world, because of the differences generated by the diversity of water and soil types, by the medium annual temperatures, by the habitation degree and by the existent fish species, the disease is generated by many species of Saprolegnia, which have different specificity and pathogenicity, depending on the factors listed above. 44
The specific literature presents updated preoccupations regarding the identificationd and classification of different Saprolegnia species and subspecies, saprophytic and conditioned pathogenic at different fish species. This fact indicates that there is not sufficient the strain morphologic strict identification, but there is needed a molecular additional characterization regarding DNA structure, which could permit a correct identification and the establishing of genetic distances between Saprolegnia populations and subpopulations. This fact is necessary because the technological losses in fish industry, raported at international and national level, caused by saprolegniasis, which are affecting the fish development from spawn, larva, alevin, young fish and adults, are reaching up to 50% from production, which has a negative impact on the fisheries economical and financial situation. Starting from those considerations, by the research hypothesis we proposed the morphologic and molecular identification and description, using DNA samples, of Saprolegnia species and subspecies, which are affecting carp species populations from centern and north-western romanian fisheries. In Romania there haven’t been made any genetic studies on Saprolegnia species and subspecies, which affect carp species, and which could be the starting point in the future for DNA vaccination technology, at reproduction individuals. The study of Saprolegnia local isolates will have an obvious contribution at the development of the disease control strategies. The research objectives were the following: 1. The establishing of experimental plan and protocole; 2. The optimization of Saprolegnia culture methods; 3. The optimization of Saprolegnia DNA extraction and amplification methods; 4. The testing of different restriction enzymes using PCR-RFLP technique; 5. The establishing of genetic distances between identified species from Saprolegniaceae family; 6. The monitor of saprolegniasis incidence at carp species from centern and northwestern part of Romania. 45
Page 1 and 2: UNIVERSITATEA DE ŞTIINłE AGRICOLE
Page 3 and 4: II.6. REZULTATELE RESTRICłIEI ENZI
Page 5 and 6: diverse specii piscicole. De aici s
Page 7 and 8: Fig.1. LocaŃiile în care s-au efe
Page 9 and 10: A fost constituit un număr de 207
Page 11 and 12: Sabouraud Dextrose Broth (SDB-bulio
Page 13 and 14: Echipament, materiale şi reactivi
Page 15 and 16: Primerii folosiŃi de către noi î
Page 17 and 18: CAPITOLUL II REZULTATELE CERCETĂRI
Page 19 and 20: Mediile diametrului coloniilor de S
Page 21 and 22: laborator specifice metodologiei de
Page 23 and 24: Deoarece am utilizat în experiment
Page 25 and 26: fragmente: primul la aproximativ 45
Page 27 and 28: II.7. REZULTATE PRIVIND STUDIUL ÎN
Page 29 and 30: mai mare genetică, indivizii despr
Page 31 and 32: MenŃionăm faptul că în toate ba
Page 33 and 34: CAPITOLUL III CONCLUZII ŞI RECOMAN
Page 35 and 36: isexualis (761 pb, o identitate de
Page 37 and 38: BIBLIOGRAFIE SELECTIVĂ 1. Colao Ma
Page 39 and 40: 19. Oroian, T.E., 2006, SelecŃia a
Page 41 and 42: UNIVERSITY OF AGRICULTURAL SCIENCES
Page 43: SPECIES FROM SAPROLEGNIACEAE FAMILY
Page 47 and 48: Fig.1. The locations where the rese
Page 49 and 50: estimation of the spawns infestatio
Page 51 and 52: pellets were filtred, washed with d
Page 53 and 54: The DNA rapid extraction using PBS
Page 55 and 56: We used a comparatively mixture of
Page 57 and 58: II.1. THE RESULTS OF SAPROLEGNIA CU
Page 59 and 60: Reading time 24 48 72 n Culture med
Page 61 and 62: asexual one. We can precisely concl
Page 63 and 64: 1 2 3 4 5 6 7 8 9 700pb- Fig.3. Ele
Page 65 and 66: pairs length. The sequencing result
Page 67 and 68: II.7. RESULTS REGARDING THE GENETIC
Page 69 and 70: higher genetic distance, the indivi
Page 71 and 72: We mention the fact that in al the
Page 73 and 74: extraction have values between 1,10
Page 75 and 76: 13. In researches on the aquatic fu
Page 77 and 78: 40. Frisvad, J.C., Bridge, P.D., Ar
Page 79: 61. *** http://www.sigmaaldrich.com

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