This paper investigates Aspergillus niger's behaviour in the presence of mobile Al3+ species by evaluating the changes in oxalate exudation at various aluminium contents. When the fungus was exposed to Al3+, no significant changes in oxalate production were observed until 100 mg.L-1 aluminium was reached resulting in oxalate production decrease by 18.2%. By stripping the culture medium completely of phosphate, even more prominent decrease by 34.8% and 67.1% at 10 and 100 mg.L-1 aluminium was observed, respectively, indicating the phosphate's significance instead of Al3+ in oxalate production. Our results suggest that the low phosphate bioavailability, which most likely resulted from its interaction with Al3+, stimulated the overproduction of oxalate by A. niger. Furthermore, when the fungus was incubated in aluminium-free media supplemented with 0.1 mM of phosphate, oxalate production increased up to 281.5 μmol.g-1, while at 1.85 mM of available phosphate only 80.7 μmol.g-1 of oxalate was produced. This indicates that oxalic acid is produced by fungus not as a mean to detoxify aluminium, but as an attempt to gain access to additional phosphate.
- Klíčová slova
- Aluminium, Aspergillus niger, Oxalate, Phosphate,
- MeSH
- Aspergillus niger účinky léků růst a vývoj metabolismus MeSH
- fosfáty nedostatek MeSH
- hliník farmakologie MeSH
- koncentrace vodíkových iontů MeSH
- kultivační média MeSH
- oxaláty metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- fosfáty MeSH
- hliník MeSH
- kultivační média MeSH
- oxaláty MeSH
The membrane-embedded FtsH proteases found in bacteria, chloroplasts, and mitochondria are involved in diverse cellular processes including protein quality control and regulation. The genome of the model cyanobacterium Synechocystis sp PCC 6803 encodes four FtsH homologs designated FtsH1 to FtsH4. The FtsH3 homolog is present in two hetero-oligomeric complexes: FtsH2/3, which is responsible for photosystem II quality control, and the essential FtsH1/3 complex, which helps maintain Fe homeostasis by regulating the level of the transcription factor Fur. To gain a more comprehensive insight into the physiological roles of FtsH hetero-complexes, we performed genome-wide expression profiling and global proteomic analyses of Synechocystis mutants conditionally depleted of FtsH3 or FtsH1 grown under various nutrient conditions. We show that the lack of FtsH1/3 leads to a drastic reduction in the transcriptional response to nutrient stress of not only Fur but also the Pho, NdhR, and NtcA regulons. In addition, this effect is accompanied by the accumulation of the respective transcription factors. Thus, the FtsH1/3 complex is of critical importance for acclimation to iron, phosphate, carbon, and nitrogen starvation in Synechocystis.plantcell;31/12/2912/FX1F1fx1.
- MeSH
- aklimatizace genetika MeSH
- bakteriální proteiny genetika metabolismus MeSH
- dusík nedostatek metabolismus MeSH
- exprese genu MeSH
- fosfáty nedostatek metabolismus MeSH
- fosforylace MeSH
- fotosystém II - proteinový komplex chemie genetika metabolismus MeSH
- metaloproteasy genetika metabolismus MeSH
- mutace MeSH
- proteiny vázající fosfáty genetika metabolismus MeSH
- proteolýza MeSH
- proteom genetika metabolismus MeSH
- proteomika MeSH
- regulace genové exprese u bakterií genetika MeSH
- regulon genetika MeSH
- represorové proteiny genetika metabolismus MeSH
- ribozomální proteiny genetika metabolismus MeSH
- Synechocystis enzymologie metabolismus MeSH
- transkripční faktory genetika metabolismus MeSH
- uhlík nedostatek metabolismus MeSH
- živiny nedostatek metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- bakteriální proteiny MeSH
- dusík MeSH
- ferric uptake regulating proteins, bacterial MeSH Prohlížeč
- fosfáty MeSH
- fotosystém II - proteinový komplex MeSH
- metaloproteasy MeSH
- proteiny vázající fosfáty MeSH
- proteom MeSH
- represorové proteiny MeSH
- ribozomální proteiny MeSH
- transkripční faktory MeSH
- uhlík MeSH
The ability of thorium uptake as well as responses to heavy metal stress were tested in tobacco cultivar La Burley 21. Thorium was accumulated preferentially in the root system. The presence of citric, tartaric and oxalic acids in hydroponic medium increased thorium accumulation in all plant organs. On the other hand, the addition of diamines and polyamines, the important antioxidants in plants, resulted in decrease of thorium accumulation, especially in the root system. Negative correlation was found between putrescine concentration and thorium accumulation. Nevertheless, the most important factor influencing the accumulation of thorium was the absence of phosphate ions in a hydroponic medium that caused more than 10-fold increase of thorium uptake in all plant parts. Accumulation and distribution of thorium was followed in six cultivars and 14 selected transformants. Cultivar La Barley 21 represented an average between the tested genotypes, having a very good distribution ratio between roots, stems and leaves.
- Klíčová slova
- Citric acid, Phosphate, Plant uptake, Polyamines, Thorium, Tobacco,
- MeSH
- diaminy chemie farmakologie MeSH
- fosfáty chemie nedostatek MeSH
- genotyp MeSH
- hydroponie MeSH
- ionty chemie MeSH
- kořeny rostlin účinky léků metabolismus MeSH
- listy rostlin účinky léků metabolismus MeSH
- polyaminy chemie farmakologie MeSH
- putrescin chemie farmakologie MeSH
- stonky rostlin účinky léků metabolismus MeSH
- tabák metabolismus MeSH
- thorium chemie metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- diaminy MeSH
- fosfáty MeSH
- ionty MeSH
- polyaminy MeSH
- putrescin MeSH
- thorium MeSH
The physiology of a commercial strain of bakers' yeast was studied in terms of the cell composition under different growth conditions and of its response to stress. The study comprised fed-batch experiments since this is the system used in bakers' yeast industry. The classical fed-batch fermentation procedure was modified in that the yeast cells were continuously grown to a steady-state at a dilution rate of 0.1/h in order to achieve more or less the same initial starting point in terms of cell composition. This steady-state culture was then switched to fed-batch concomitantly with exposure to stress. The highest amount of trehalose accumulation was achieved when nutrient depletion and heat stress were applied concomitantly. The highest amount of trehalose, 12%, was attained in cells stressed by both nitrogen depletion and heat stress. The protein content remained constant, although with some oscillations, at a value of 30% throughout this dual stress experiment.
- MeSH
- biomasa MeSH
- dusík nedostatek MeSH
- fosfáty nedostatek MeSH
- fungální proteiny analýza MeSH
- Saccharomyces cerevisiae fyziologie MeSH
- vysoká teplota MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
- Názvy látek
- dusík MeSH
- fosfáty MeSH
- fungální proteiny MeSH