Olga Dadali - Academia.edu (original) (raw)

Papers by Olga Dadali

Research paper thumbnail of High-Resolution Melting (HRM) Analysis Reveals Genotypic Differentiation of Venturia inaequalis Populations in Greece

Frontiers in Ecology and Evolution

During the recent years, High Resolution Melting (HRM) analysis has been developed as a rapid and... more During the recent years, High Resolution Melting (HRM) analysis has been developed as a rapid and accurate tool in plant disease diagnostics, species identification and SNP genotyping. This approach has been applied to analyze the genetic diversity in several plant species with molecular markers, including single sequence repeats (SSR). However, no studies have been carried out to investigate the variation of SSR in plant pathogenic fungi by using the HRM technology. In this report, the genetic structure of Venturia inaequalis populations in Greece was investigated for the first time by using six microsatellite markers. The developed HRM protocol was able to generate genotype-specific melting curves, consistent with the haploid nature of the fungus. Unknown samples were genotyped using standard samples as reference controls among multiple runs. Compared to the more complex genome of diploid plants, several limitations were avoided. The shape of the melting curves revealed differences between the genotypes in each SSR marker and showed that all the genotypes could be easily distinguished. The genetic analysis of apple scab populations revealed high genetic variation within the populations (96%), while only 4% of the total gene diversity was attributed to among-population variation. The isolates were grouped into three higher-level populations according to the principal coordinate analysis (PCoA).

Research paper thumbnail of Early diagnosis of enteromyxosis in intensively reared sharpsnout sea bream (Diplodus puntazzo): preliminary results

Karatzinos T, Golomazou E, Malandrakis EE, Dadali O, Martsikalis P, Neofitou N, Exadactylos A, Panagiotaki P, Oct 1, 2012

Research paper thumbnail of Comparison of four slaughtering methods on stress response of intensively cultured gilthead seabream (Sparus aurata)

Research paper thumbnail of Partial replacement of fresh algae with dry, in intensive seabream larval production

Dimopoulos D, Panagiotaki P, Golomazou E, Malandrakis EE, Dadali O, Martsikalis P, Exadactylos A, Klaoudatos S, Neofitou C, 2010

Green water technique was developed in order to improve survival and growth rate of post hatched ... more Green water technique was developed in order to improve survival and growth rate of post hatched gilthead seabream (Sparus aurata) larvae intensively produced. In parallel, this created the need of algal cultivation in hatcheries, a fact that elaborated complicated procedures and increased the cost of larval production. Recently, world aquaculture, in order to minimize the production cost, seems to have bypassed the hatching procedure of fresh algal cultivation by substituting them with commercially produced dry algae. In the present study, the hypothesis that a 50% substitution fresh algae with dry, can improve survival, growth and malformation rate in commercial scale, was investigated. Simultaneously, a feeding frequency of 3 and 5 Artemia sp. meals per day was studied. Four treatments were established and quadruplicates were maintained for each treatment. Treatments included: a) 50% replacement of fresh algae with dry (SanolifeALG, INVE) and 3 daily feedings (SL 3T), b) 50% replacement of fresh algae with dry and 5 daily feedings (SL 5T), c) 5 daily feedings (M 5T) control group and d) 3 daily feedings (M 3T) control group. Samples of larvae were measured for length at days 5, 13, 19, 25, 32 and 40 post hatching. Partial substitution (50%) of fresh algae with dry provoked no difference in growth, survival and malformation rate, reducing algal production cost by 8%. Moreover, risk of pathogen contamination is reduced and the nutrition quality of live prey is stabilized. Feeding frequency affected significantly larval growth rate (5 feedings compared 3 feedings), when either fresh or dry algae were used. From the present study it appears that partial substitution of dry algae with fresh, can sustain low larval production cost and secure a standard procedure, main points of interest for a commercial hatchery. Dry algae, based on technology achievements, are strongly recommended for use as a “rescue plan”, in case that fresh algal cultures collapse. More research is needed, in order to improve aquaculture techniques and develop qualified products – in collaboration with hatcheries – so as to achieve total substitution of fresh, by dry algae

Research paper thumbnail of High-Resolution Melting (HRM) Analysis Reveals Genotypic Differentiation of Venturia inaequalis Populations in Greece

Frontiers in Ecology and Evolution

During the recent years, High Resolution Melting (HRM) analysis has been developed as a rapid and... more During the recent years, High Resolution Melting (HRM) analysis has been developed as a rapid and accurate tool in plant disease diagnostics, species identification and SNP genotyping. This approach has been applied to analyze the genetic diversity in several plant species with molecular markers, including single sequence repeats (SSR). However, no studies have been carried out to investigate the variation of SSR in plant pathogenic fungi by using the HRM technology. In this report, the genetic structure of Venturia inaequalis populations in Greece was investigated for the first time by using six microsatellite markers. The developed HRM protocol was able to generate genotype-specific melting curves, consistent with the haploid nature of the fungus. Unknown samples were genotyped using standard samples as reference controls among multiple runs. Compared to the more complex genome of diploid plants, several limitations were avoided. The shape of the melting curves revealed differences between the genotypes in each SSR marker and showed that all the genotypes could be easily distinguished. The genetic analysis of apple scab populations revealed high genetic variation within the populations (96%), while only 4% of the total gene diversity was attributed to among-population variation. The isolates were grouped into three higher-level populations according to the principal coordinate analysis (PCoA).

Research paper thumbnail of Early diagnosis of enteromyxosis in intensively reared sharpsnout sea bream (Diplodus puntazzo): preliminary results

Karatzinos T, Golomazou E, Malandrakis EE, Dadali O, Martsikalis P, Neofitou N, Exadactylos A, Panagiotaki P, Oct 1, 2012

Research paper thumbnail of Comparison of four slaughtering methods on stress response of intensively cultured gilthead seabream (Sparus aurata)

Research paper thumbnail of Partial replacement of fresh algae with dry, in intensive seabream larval production

Dimopoulos D, Panagiotaki P, Golomazou E, Malandrakis EE, Dadali O, Martsikalis P, Exadactylos A, Klaoudatos S, Neofitou C, 2010

Green water technique was developed in order to improve survival and growth rate of post hatched ... more Green water technique was developed in order to improve survival and growth rate of post hatched gilthead seabream (Sparus aurata) larvae intensively produced. In parallel, this created the need of algal cultivation in hatcheries, a fact that elaborated complicated procedures and increased the cost of larval production. Recently, world aquaculture, in order to minimize the production cost, seems to have bypassed the hatching procedure of fresh algal cultivation by substituting them with commercially produced dry algae. In the present study, the hypothesis that a 50% substitution fresh algae with dry, can improve survival, growth and malformation rate in commercial scale, was investigated. Simultaneously, a feeding frequency of 3 and 5 Artemia sp. meals per day was studied. Four treatments were established and quadruplicates were maintained for each treatment. Treatments included: a) 50% replacement of fresh algae with dry (SanolifeALG, INVE) and 3 daily feedings (SL 3T), b) 50% replacement of fresh algae with dry and 5 daily feedings (SL 5T), c) 5 daily feedings (M 5T) control group and d) 3 daily feedings (M 3T) control group. Samples of larvae were measured for length at days 5, 13, 19, 25, 32 and 40 post hatching. Partial substitution (50%) of fresh algae with dry provoked no difference in growth, survival and malformation rate, reducing algal production cost by 8%. Moreover, risk of pathogen contamination is reduced and the nutrition quality of live prey is stabilized. Feeding frequency affected significantly larval growth rate (5 feedings compared 3 feedings), when either fresh or dry algae were used. From the present study it appears that partial substitution of dry algae with fresh, can sustain low larval production cost and secure a standard procedure, main points of interest for a commercial hatchery. Dry algae, based on technology achievements, are strongly recommended for use as a “rescue plan”, in case that fresh algal cultures collapse. More research is needed, in order to improve aquaculture techniques and develop qualified products – in collaboration with hatcheries – so as to achieve total substitution of fresh, by dry algae