Charoula Psallida


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Publications (3)5.39 Total impact

  • C. Psallida · C.G. Spyropoulos
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    ABSTRACT: Micropylar endosperm endo-β-mannanase of Lycopersicon esculenium (tomato) seeds hydrolyzes the mannan polysaccharides of the micropylar cell walls, allowing radicle protrusion. However, there is a controversy whether micropylar endo-β-mannanase is the limiting factor for tomato seed germination. In this report it is investigated whether endosperm endo-β-mannanase activity, which appeared during early tomato seed imbibition, was related to the germination ability of four cultivars (ACE, Olympia, Macedonia and Thessaloniki), the seeds of which were subjected to treatments that altered their germination behaviour and then germinated at three different temperatures. A high correlation (P<0.001) existed between log endosperm mannanase activity of 24-h-imbibed non-germinated seeds and the corresponding germination indices of the resultant 16 different seed lots for seeds germinated at 25°C. In contrast, the correlation was lower when seeds were imbibed at 18, or 12°C. The results presented in this report are suggestive of a causative role for endosperm mannanase activity, in the germination of the studied tomato cultivars, at favorable temperatures, and that mannanase activity of 24-h-imbibed non-germinated seeds could be used as a marker for the ability of the examined cultivars to germinate at 25°C.
    No preview · Article · Oct 2006 · Seed Science and Technology
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    ABSTRACT: A generic sample normalization method applicable in relative comparison of mRNAs quantified with real-time polymerase chain reaction (PCR) is proposed. The method was applied in samples obtained from tomato seeds after osmopriming and aging treatments and from untreated seeds at early imbibition stage, when seeds had not completed germination. Normalization in sample variations was accomplished by detecting synthetic DNA sequences tailing cDNA after second strand reverse transcription synthesis, while the use of the common normalizer GAPDH proved unreliable. Results, obtained from the new method and having a standard error less than 10%, verified the expression profile of a germination-specific mannanase gene that was closely recorded at different time intervals in relation to seed germination.
    Full-text · Article · Mar 2006 · FEBS Journal
  • Charoula Psallida · Dimitris Argyropoulos
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    ABSTRACT: Messenger ribonucleic acid (mRNA) isolation from tomato seeds was performed with the PolyATtract System 1000 and was evaluated in two-step Real Time PCR using the fluoresence dye Sybr Green. The proposed isolation method resulted in cDNA production with Sybr Green 11-fold higher fluorescence intensity, having 87% lower standard deviation in the recorded fluorescence signals, and PCR efficiency improved by 21% in comparison to mRNA samples obtained with the manufacturer's protocol. The method for the assessment of the mRNA isolation procedure and the proposed mathematical analysis of the data are applicable to gene identification and expression studies for biotechnological applications.
    No preview · Article · Feb 2005 · Preparative Biochemistry & Biotechnology