Fission yeast 'cut' mutants show defects in temporal coordination of nuclear division with cytokinesis, resulting in aberrant mitosis and lethality. Among other causes, the 'cut' phenotype can be triggered by genetic or chemical perturbation of lipid metabolism, supposedly resulting in shortage of membrane phospholipids and insufficient nuclear envelope expansion during anaphase. Interestingly, penetrance of the 'cut' phenotype in mutants of the transcription factor cbf11 and acetyl-coenzyme A carboxylase cut6, both related to lipid metabolism, is highly dependent on growth media, although the specific nutrient(s) affecting 'cut' occurrence is not known. In this study, we set out to identify the growth media component(s) responsible for 'cut' phenotype suppression in Δcbf11 and cut6-621 cells. We show that mitotic defects occur rapidly in Δcbf11 cells upon shift from the minimal EMM medium ('cut' suppressing) to the complex YES medium ('cut' promoting). By growing cells in YES medium supplemented with individual EMM components, we identified ammonium chloride, an efficiently utilized nitrogen source, as a specific and potent suppressor of the 'cut' phenotype in both Δcbf11 and cut6-621. Furthermore, we found that ammonium chloride boosts lipid droplet formation in wild-type cells. Our findings suggest a possible involvement of nutrient-responsive signaling in 'cut' suppression.
- MeSH
- acetyl-CoA-karboxylasa genetika MeSH
- chlorid amonný chemie metabolismus farmakologie MeSH
- fenotyp MeSH
- kultivační média chemie MeSH
- lipidová tělíska účinky léků metabolismus MeSH
- metabolismus lipidů účinky léků genetika MeSH
- mitóza účinky léků genetika MeSH
- mutace MeSH
- penetrance MeSH
- Schizosaccharomyces pombe - proteiny genetika MeSH
- Schizosaccharomyces účinky léků genetika růst a vývoj metabolismus MeSH
- transkripční faktory genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
MAIN CONCLUSION: Nepenthes regulates enzyme activities by sensing stimuli from the insect prey. Protein is the best inductor mimicking the presence of an insect prey. Carnivorous plants of the genus Nepenthes have evolved passive pitcher traps for prey capture. In this study, we investigated the ability of chemical signals from a prey (chitin, protein, and ammonium) to induce transcription and synthesis of digestive enzymes in Nepenthes × Mixta. We used real-time PCR and specific antibodies generated against the aspartic proteases nepenthesins, and type III and type IV chitinases to investigate the induction of digestive enzyme synthesis in response to different chemical stimuli from the prey. Transcription of nepenthesins was strongly induced by ammonium, protein and live prey; chitin induced transcription only very slightly. This is in accordance with the amount of released enzyme and proteolytic activity in the digestive fluid. Although transcription of type III chitinase was induced by all investigated stimuli, a significant accumulation of the enzyme in the digestive fluid was found mainly after protein and live prey addition. Protein and live prey were also the best inducers for accumulation of type IV chitinase in the digestive fluid. Although ammonium strongly induced transcription of all investigated genes probably through membrane depolarization, strong acidification of the digestive fluid affected stability and abundance of both chitinases in the digestive fluid. The study showed that the proteins are universal inductors of enzyme activities in carnivorous pitcher plants best mimicking the presence of insect prey. This is not surprising, because proteins are a much valuable source of nitrogen, superior to chitin. Extensive vesicular activity was observed in prey-activated glands.
- MeSH
- Caryophyllales enzymologie fyziologie ultrastruktura MeSH
- chitin metabolismus MeSH
- chlorid amonný farmakologie MeSH
- enzymy genetika metabolismus MeSH
- koncentrace vodíkových iontů MeSH
- masožravci MeSH
- membránové potenciály MeSH
- regulace genové exprese u rostlin * MeSH
- rostlinné proteiny genetika metabolismus MeSH
- sérový albumin hovězí metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
Metabolic acidosis could occur due to either endogenous acids accumulation or bicarbonate loss from the gastrointestinal tract or commonly from the kidney. This study aimed to investigate the possible underlying mechanism(s) of chronic acidosis-induced cardiac contractile and electrical changes in rats. Twenty four adult Wistar rats, of both sexes, were randomly divided into control group and chronic metabolic acidosis group, which received orally 0.28 M NH(4)Cl in the drinking water for 2 weeks. At the end of experimental period, systolic and diastolic blood pressure values were measured. On the day of sacrifice, rats were anesthetized by i.p. pentobarbitone (40 mg/kg b.w.), transthoracic echocardiography and ECG were performed. Blood samples were obtained from abdominal aorta for complete blood count and determination of pH, bicarbonate, chloride, sodium, potassium, troponin I, CK-MB, IL-6, renin and aldosterone levels. Hearts from both groups were studied for cardiac tissue IL-6 and aldosterone in addition to histopathological examination. Compared to control group, chronic metabolic acidosis group showed anemia, significant systolic and diastolic hypotension accompanied by significant reduction of ejection fraction and fraction of shortening, significant bradycardia, prolonged QTc interval and higher widened T wave as well as significantly elevated plasma levels of renin, aldosterone, troponin I, CK-MB and IL-6, and cardiac tissue aldosterone and IL-6. The left ventricular wall of the acidosis group showed degenerated myocytes with fibrosis and apoptosis. Thus, chronic metabolic acidosis induced negative inotropic and chronotropic effects and cardiomyopathy, possibly by elevated aldosterone and IL-6 levels released from the cardiac tissue.
- MeSH
- acidóza chemicky indukované komplikace patofyziologie MeSH
- aldosteron metabolismus MeSH
- chlorid amonný * MeSH
- chronická nemoc MeSH
- echokardiografie MeSH
- elektrokardiografie MeSH
- funkční vyšetření srdce MeSH
- interleukin-6 metabolismus MeSH
- kontrakce myokardu * MeSH
- krysa rodu rattus MeSH
- myokard chemie metabolismus MeSH
- nemoci srdce chemicky indukované diagnostické zobrazování patofyziologie MeSH
- potkani Wistar MeSH
- srdeční frekvence MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Diatoms are especially important microorganisms because they constitute the larger group of microalgae. To survive the constant variations of the light environment, diatoms have developed mechanisms aiming at the dissipation of excess energy, such as the xanthophyll cycle and the non-photochemical chlorophyll (Chl) fluorescence quenching. This contribution is dedicated to the relaxation of the latter process when the adverse conditions cease. An original nonlinear regression analysis of the relaxation of non-photochemical Chl fluorescence quenching, qN, in diatoms is presented. It was used to obtain experimental evidence for the existence of three time-resolved components in the diatom Phaeodactylum tricornutum: qNf, qNi and qNs. qNf (s time-scale) and qNs (h time-scale) are exponential in shape. By contrast, qNi (min time-scale) is of sigmoidal nature and is dominant among the three components. The application of metabolic inhibitors (dithiothreitol, ammonium chloride, cadmium and diphenyleneiodonium chloride) allowed the identification of the mechanisms on which each component mostly relies. qNi is linked to the relaxation of the ΔpH gradient and the reversal of the xanthophyll cycle. qNs quantifies the stage of photoinhibition caused by the high light exposure, qNf seems to reflect fast conformational changes within thylakoid membranes in the vicinity of the photosystem II complexes.
- MeSH
- časové faktory MeSH
- chlorid amonný MeSH
- chlorofyl metabolismus účinky záření MeSH
- dithiothreitol MeSH
- fluorescence MeSH
- fotosystém II (proteinový komplex) metabolismus MeSH
- kadmium MeSH
- kinetika MeSH
- oniové sloučeniny MeSH
- regresní analýza MeSH
- rozsivky fyziologie MeSH
- světlo * MeSH
- tylakoidy metabolismus MeSH
- xanthofyly metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Using a codon-optimized gene fragment, we report remarkable yields for extracellular domain of human NK cell receptor (NKp30ex) when produced on M9 minimal medium, even with low (2g/L) glucose concentration. The yields were identical using media containing (15)NH(4)Cl or (15)NH(4)Cl in combination with all-(13)C-d-glucose allowing to produce homogenous soluble monomeric NKp30 in several formats needed for advanced NMR studies. Our optimized protocol now allows to produce routinely 10mg batches of these NKp30ex proteins per 1L of M9 production medium in four working days. The purity and identity of the produced proteins were checked by SDS-PAGE, MALDI MS peptide mapping, and high resolution ion cyclotron resonance MS. Analytical ultracentrifugation confirmed the monomeric status of the produced proteins. Long-term stability of the produced protein proved to be very good allowing its use for NMR studies using elevated temperatures. These studies should reveal further details of the interaction of NKp30 with several of its ligands including target cell surface proteins and heparin-derived oligosaccharides.
- MeSH
- bioreaktory MeSH
- chlorid amonný chemie MeSH
- elektroforéza v polyakrylamidovém gelu MeSH
- Escherichia coli chemie genetika metabolismus MeSH
- kodon MeSH
- lidé MeSH
- molekulární sekvence - údaje MeSH
- nukleární magnetická rezonance biomolekulární metody MeSH
- receptor 3 spouštějící přirozenou cytotoxicitu biosyntéza chemie genetika metabolismus MeSH
- rekombinantní proteiny chemie genetika metabolismus MeSH
- rozpustnost MeSH
- sbalování proteinů MeSH
- sekvence aminokyselin MeSH
- sekvence nukleotidů MeSH
- ultracentrifugace MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- acidóza enzymologie etiologie chemicky indukované MeSH
- chlorid amonný aplikace a dávkování škodlivé účinky MeSH
- GABA metabolismus MeSH
- glutamát dekarboxyláza metabolismus MeSH
- glutamáty metabolismus MeSH
- krysa rodu rattus MeSH
- kůra ledviny metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
