|
|
Optimalizace procesu triploidizace u candáta obecného (Sander lucioperca)
TRNKA, Kamil
This thesis was aimed on optimization of induction of triploidization of pikeperch (Sander lucioperca) using cold, hot and pressure shocks. To induce the triploid status of the larvae using cold shock fertilized eggs of pikeperch were dropped into the cold bath of temperature 0,5-1°C in 2, 4, 8, 12 and 16 minutes post fertilization with shock duration of 20, 40, 60, 90 and 120 minutes. Hot shock was induced by 30°C bath 2, 4, 8, 12 and 16 minutes post fertilization with duration of shock 5, 10, 20, 30 and 40 minutes. Pressure shock was also tested for induction of triploidization using pressure of 70 MPa 5, 10 and 20 minutes post fertilization with duration of shock 5 minutes. Ploidy level was then determineted using flow cytometry. As a result hatchability (%), share of malformed larvae (%), share of triploid individuals (%) and yield of triploids (%) were determined. None of the experiemental shocks have led to a 100% share of triploids concerning the samples examined by flow cytometry. Best result was reached via pressure shock with duration of 20minutes which resulted with share of triploid individuals of 95% and yield of triploids 12.2+-2.5%. It must be noticed that increasing duration of pressure shock resulted in decreased hatchability and increased share of malformed larvae. Second best result was achieved via cold shock. Worst results were obtained via hot shock.
|
|
|
Cold adaptation in stationary phase in Bacillus subtilis
Beranová, Anna ; Konopásek, Ivo (advisor) ; Svobodová, Jaroslava (referee)
Cold adaptation in stationary phase in Bacillus subtilis One of the most important abiotic factor which influences life of bacterial cells is the ambient temperature. A decrease of this temperature is usually accompanied usually with the loss of the fluidity of bacterial cytoplasmatic membrane. While the mechanisms of the responses to the cold shock during the exponential phase of growth are well known for Bacillus subtilis, the responses of stationary phase cells had not been studied yet (despite the stationary phase is the most common state of microorganism in the nature). There are two independent mechanisms which restores much needed fluidity in Bacillus subtilis - short-term adaptation and long-term adaptation. Short-term adaptation is based on the function of fatty acid desaturase coded by des gene. Long-term adaptation relies on the change in ratio of iso- and anteiso- branched fatty acids. In this work we examinated membrane adaptation during stationary phase under two different conditions, namely under cultivation at stable low temperature and after cold shock. The highest activity of Pdes was observed for cultivation at 25 řC and for the cold shock applied from cultivation in 37 řC to 25 řC. Anisotropy measurements and fatty acids analysis were also performed. Results indicated, that the...
|
|
|
Indukce triploidie u candáta obecného (Sander lucioperca)
RŮŽEK, Martin
The aim of this study was to induce the triploidy in pikeperch (Sander lucioperca) with use of a cold shock. To induce the triploidy, fertilised egg were (spawning temperature 14,5 °C) submerged in a cold bath at the temperature of 2 °C. Time of initiation was 1; 3; 5; 7 and 10 minutes post activation. The exposure time was 20 and 40 minutes. Ploidy level of freshly hatched larvae was assessed with use of the flow cytometry. In both exposure times, the hatching rate was getting lower with later time of initiation (20 minutes exposure, hatching rate: 58,4-13,4 %; 40 minutes exposure, hatching rate: 28- 9,6 %). Number of malformed larvae increased with later time of initiation and longer exposure time (20 minutes exposure, malformed larvae 0-47,2 %; 40 minutes exposure, malformed larvae 0-58,8 %). None of the tested combination of exposure time and time of initiation led to a population containing 100 % triploid larvae. However, percentage of triploid larvae grew up with longer exposure time and later time of initiation. The best cold shock combination with highest yield of triploids were after 20 minutes long treatment initiated 10 minutes post activation (57,1 +- 14,2 %) and after 40 minutes long treatment initiated 10 minutes post activation (61,9 +- 8,2 %). The most important finding of this study is that cold shock treatment leads to triploidy in pikeperch. To obtain 100% triploid larvae, shorter exposure time and different shock temperature might be applied. It may also eliminate low hatching rate and high appearance of malformed larvae.
|
|
|
Cold adaptation in stationary phase in Bacillus subtilis
Beranová, Anna ; Konopásek, Ivo (advisor) ; Svobodová, Jaroslava (referee)
Cold adaptation in stationary phase in Bacillus subtilis One of the most important abiotic factor which influences life of bacterial cells is the ambient temperature. A decrease of this temperature is usually accompanied usually with the loss of the fluidity of bacterial cytoplasmatic membrane. While the mechanisms of the responses to the cold shock during the exponential phase of growth are well known for Bacillus subtilis, the responses of stationary phase cells had not been studied yet (despite the stationary phase is the most common state of microorganism in the nature). There are two independent mechanisms which restores much needed fluidity in Bacillus subtilis - short-term adaptation and long-term adaptation. Short-term adaptation is based on the function of fatty acid desaturase coded by des gene. Long-term adaptation relies on the change in ratio of iso- and anteiso- branched fatty acids. In this work we examinated membrane adaptation during stationary phase under two different conditions, namely under cultivation at stable low temperature and after cold shock. The highest activity of Pdes was observed for cultivation at 25 řC and for the cold shock applied from cultivation in 37 řC to 25 řC. Anisotropy measurements and fatty acids analysis were also performed. Results indicated, that the...
|
|
|
Transcriptional analysis of selected stress proteins in larvae of the fruit fly, \kur{Drosophila melanogaster} (Diptera: Drosophilidae
KORBELOVÁ, Jaroslava
We assessed influence of three acclimation regimes and influence of recovery after cold shock (exposure to 0°C for a period of time corresponding to Lt25) on the relative mRNA levels of selected stress proteins using qRT-PCR method. Larvae acclimated at 25°C showed relatively weak upregulation responses to cold shock. Much stronger responses were observed in the larvae that were cold-acclimated at 15°C or 15°C ? 6°C prior to cold shock. Two different general trends were distinguished in the response to cold acclimation and cold shock: (a) proteins from families SP70 and SP90 and splice variants c and d of the transcription factor HSF were upregulated in response to cold acclimation and the levels of their mRNA transcripts further increased after cold shock (for instance, the abundance of hsp70Aa mRNA increased up to 300-fold after cold shock (acclimation variant 15°C ? 6°C)); (b) four members of the small Hsp family (22, 23, 26 and 27 kDa) and splice variants a and b of the transcription factor HSF were down-regulated during cold acclimation (for instance, 10-fold in the case of hsp22) and the levels of their mRNA transcripts were either unchanged or increased only moderately after the cold shock. A third group of proteins, namely Hsc70, Hsp40 showed no or relatively small changes.
|
guest ::
