The sessile life style of plants creates the need to deal with an often adverse environment, in which water availability can change on a daily basis, challenging the cellular physiology and integrity. Changes in osmotic conditions disrupt the equilibrium of the plasma membrane: hypoosmotic conditions increase and hyperosmotic environment decrease the cell volume. Here, we show that short-term extracellular osmotic treatments are closely followed by a shift in the balance between endocytosis and exocytosis in root meristem cells. Acute hyperosmotic treatments (ionic and nonionic) enhance clathrin-mediated endocytosis simultaneously attenuating exocytosis, whereas hypoosmotic treatments have the opposite effects. In addition to clathrin recruitment to the plasma membrane, components of early endocytic trafficking are essential during hyperosmotic stress responses. Consequently, growth of seedlings defective in elements of clathrin or early endocytic machinery is more sensitive to hyperosmotic treatments. We also found that the endocytotic response to a change of osmotic status in the environment is dominant over the presumably evolutionary more recent regulatory effect of plant hormones, such as auxin. These results imply that osmotic perturbation influences the balance between endocytosis and exocytosis acting through clathrin-mediated endocytosis. We propose that tension on the plasma membrane determines the addition or removal of membranes at the cell surface, thus preserving cell integrity.

• MeSH
• Arabidopsis cytologie   účinky léků   metabolismus   MeSH
• buněčná membrána účinky léků   metabolismus   MeSH
• endocytóza * účinky léků   MeSH
• exocytóza * účinky léků   MeSH
• fyziologická adaptace účinky léků   MeSH
• genový knockdown MeSH
• klathrin metabolismus   MeSH
• kyseliny indoloctové farmakologie   MeSH
• mutace genetika   MeSH
• osmotický tlak * účinky léků   MeSH
• proteiny huseníčku metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Polyhydroxyalkanoates are microbial polyesters which are considered being biological alternatives to petrochemical polymers. Extremophiles, such as thermophilic PHA producers, hold promise to improve competitiveness of PHA production process. Therefore, this work aimed at isolation of new strains, which could produce PHA under elevated temperature. Since traditional Nile red staining of colonies provided false positive results in thermophiles, we developed a novel strategy of enriching microbial consortia by PHA producers. This so called "osmoselective strategy" is based on application of osmotic challenge by sudden exposition of the mixed microbial culture to hypertonic and subsequently to hypotonic conditions; moreover, this strategy relies on the fact that PHA protect bacteria from negative effects of rapid fluctuations in osmotic pressure. In combination with fast and reliable ATR-FTIR inspection of selected colonies for presence of PHA, we were able to isolate several promising thermophilic or thermotolerant PHA producing strains belonging to the genera Bacillus, Aneurinibacillus and Chelatococcus, which indeed deserves further investigation to evaluate their potential for industrial production of PHA.

• MeSH
• Alphaproteobacteria izolace a purifikace   MeSH
• Bacillales izolace a purifikace   MeSH
• Bacillus izolace a purifikace   MeSH
• Bacteria izolace a purifikace   MeSH
• bioreaktory MeSH
• DNA bakterií MeSH
• fermentace MeSH
• mikrobiální společenstva * MeSH
• osmóza MeSH
• polyhydroxyalkanoáty chemie   MeSH
• sekvence nukleotidů MeSH
• termotolerance MeSH
• vysoká teplota MeSH
• Publikační typ
• časopisecké články MeSH

The maintenance of plasma sodium concentration within a narrow limit is crucial to life. When it differs from normal physiological patterns, several mechanisms are activated in order to restore body fluid homeostasis. Such mechanisms may be vegetative and/or behavioral, and several regions of the central nervous system (CNS) are involved in their triggering. Some of these are responsible for sensory pathways that perceive a disturbance of the body fluid homeostasis and transmit information to other regions. These regions, in turn, initiate adequate adjustments in order to restore homeostasis. The main cardiovascular and autonomic responses to a change in plasma sodium concentration are: i) changes in arterial blood pressure and heart rate; ii) changes in sympathetic activity to the renal system in order to ensure adequate renal sodium excretion/absorption, and iii) the secretion of compounds involved in sodium ion homeostasis (ANP, Ang-II, and ADH, for example). Due to their cardiovascular effects, hypertonic saline solutions have been used to promote resuscitation in hemorrhagic patients, thereby increasing survival rates following trauma. In the present review, we expose and discuss the role of several CNS regions involved in body fluid homeostasis and the effects of acute and chronic hyperosmotic challenges.

• MeSH
• centrální nervový systém účinky léků   fyziologie   MeSH
• hemoragický šok farmakoterapie   patofyziologie   MeSH
• homeostáza účinky léků   fyziologie   MeSH
• hypertonický solný roztok aplikace a dávkování   MeSH
• krevní tlak účinky léků   fyziologie   MeSH
• ledviny účinky léků   fyziologie   MeSH
• lidé MeSH
• nervová síť fyziologie   MeSH
• osmóza účinky léků   fyziologie   MeSH
• srdeční frekvence účinky léků   fyziologie   MeSH
• tělesné tekutiny účinky léků   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Objective of this study was to characterize osmotically-induced insulin secretion in two tumor cell lines. We compared response of freshly isolated rat pancreatic islets and INS-1 and INS-1E tumor cell lines to high glucose, 30 % hypotonic medium and 20 % hypertonic medium. In Ca2+-containing medium glucose induced insulin release in all three cell types. Hypotonicity induced insulin secretion from islets and INS-1 cells but not from INS-1E cells, in which secretion was inhibited despite similar increase in cell volume in both cell types. GdCl3 (100 µmol/l) did not affect insulin response from INS-1E cells to hypotonic challenge. Hypertonic medium inhibited glucose-induced insulin secretion from islets but not from tumor cells. Noradrenaline (1 µmol/l) inhibited glucose-induced but not swelling-induced insulin secretion from INS-1 cells. Surprisingly, perifusion with Ca2+-depleted medium showed distinct secretory response of INS-1E cells to hypotonicity while that of INS-1 cells was partially inhibited. Functioning glucose-induced insulin secretion is not sufficient prerequisite for hypotonicity-induced response in INS- 1E cells suggesting that swelling-induced exocytosis is not essential step in the mechanism mediating glucose-induced insulin secretion. Both cell lines are resistant to inhibitory effect of hyperosmolarity on glucose-induced insulin secretion. Response of INS-1E cells to hypotonicity is inhibited by the presence of Ca2+ in medium.

• Klíčová slova
• Cell volume, Insulin secretion, Pancreatic islets, Tumor cell line, Ca2+ and exocytosis,
• MeSH
• exocytóza MeSH
• financování organizované MeSH
• gadolinium farmakologie   MeSH
• glukosa metabolismus   MeSH
• hypertonické roztoky MeSH
• hypotonické roztoky MeSH
• inzulin sekrece   MeSH
• inzulinom metabolismus   sekrece   MeSH
• krysa rodu rattus MeSH
• Langerhansovy ostrůvky metabolismus   sekrece   účinky léků   MeSH
• nádorové buněčné linie MeSH
• nádory slinivky břišní metabolismus   sekrece   MeSH
• noradrenalin metabolismus   MeSH
• osmotický tlak MeSH
• potkani Wistar MeSH
• vápník metabolismus   nedostatek   MeSH
• velikost buňky MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH

Polyhydroxyalkanoates (PHA) are microbial polyesters which accumulate as intracellular granules in numerous prokaryotes and mainly serve as storage materials; beyond this primary function, PHA also enhance the robustness of bacteria against various stress factors. We have observed that the presence of PHA in bacterial cells substantially enhances their ability to maintain cell integrity when suddenly exposed to osmotic imbalances. In the case of the non-halophilic bacterium Cupriavidus necator, the presence of PHA decreased plasmolysis-induced cytoplasmic membrane damage during osmotic up-shock, which subsequently enabled the cells to withstand subsequent osmotic downshock. In contrast, sudden induction of osmotic up- and subsequent down-shock resulted in massive hypotonic lysis of non-PHA containing cells as determined by Transmission Electron Microscopy and Thermogravimetrical Analysis. Furthermore, a protective effect of PHA against hypotonic lysis was also observed in the case of the halophilic bacterium Halomonas halophila; here, challenged PHA-rich cells were capable of retaining cell integrity more effectively than their PHA-poor counterparts. Hence, it appears that the fact that PHA granules, as an added value to their primary storage function, protect halophiles from the harmful effect of osmotic down-shock might explain why PHA accumulation is such a common feature among halophilic prokaryotes. The results of this study, apart from their fundamental importance, are also of practical biotechnological significance: because PHA-rich bacterial cells are resistant to osmotic imbalances, they could be utilized in in-situ bioremediation technologies or during enrichment of mixed microbial consortia in PHA producers under conditions of fluctuating salinity.

• MeSH
• Bacteria cytologie   účinky léků   metabolismus   MeSH
• Cupriavidus necator cytologie   účinky léků   metabolismus   ultrastruktura   MeSH
• Halomonas cytologie   účinky léků   metabolismus   ultrastruktura   MeSH
• mikrobiální viabilita účinky léků   MeSH
• osmóza * MeSH
• polyhydroxyalkanoáty farmakologie   MeSH
• teplota MeSH
• termogravimetrie MeSH
• Publikační typ
• časopisecké články MeSH

Quantitative phase imaging (QPI) brought innovation to noninvasive observation of live cell dynamics seen as cell behavior. Unlike the Zernike phase contrast or differential interference contrast, QPI provides quantitative information about cell dry mass distribution. We used such data for objective evaluation of live cell behavioral dynamics by the advanced method of dynamic phase differences (DPDs). The DPDs method is considered a rational instrument offered by QPI. By subtracting the antecedent from the subsequent image in a time-lapse series, only the changes in mass distribution in the cell are detected. The result is either visualized as a two dimensional color-coded projection of these two states of the cell or as a time dependence of changes quantified in picograms. Then in a series of time-lapse recordings, the chain of cell mass distribution changes that would otherwise escape attention is revealed. Consequently, new salient features of live cell behavior should emerge. Construction of the DPDs method and results exhibiting the approach are presented. Advantage of the DPDs application is demonstrated on cells exposed to an osmotic challenge. For time-lapse acquisition of quantitative phase images, the recently developed coherence-controlled holographic microscope was employed.

• MeSH
• buněčné linie MeSH
• cytologické techniky metody   MeSH
• holografie metody   MeSH
• krysa rodu rattus MeSH
• mikroskopie metody   MeSH
• osmotický tlak fyziologie   MeSH
• tvar buňky fyziologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Osmoregulation is the homeostatic mechanism essential for the survival of organisms in hypoosmotic and hyperosmotic conditions. In freshwater or soil dwelling protists this is frequently achieved through the action of an osmoregulatory organelle, the contractile vacuole. This endomembrane organelle responds to the osmotic challenges and compensates by collecting and expelling the excess water to maintain the cellular osmolarity. As compared with other endomembrane organelles, this organelle is underappreciated and under-studied. Here we review the reported presence or absence of contractile vacuoles across eukaryotic diversity, as well as the observed variability in the structure, function, and molecular machinery of this organelle. Our findings highlight the challenges and opportunities for constructing cellular and evolutionary models for this intriguing organelle.

• MeSH
• Eukaryota * fyziologie   MeSH
• osmoregulace fyziologie   MeSH
• vakuoly * MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Numerous prokaryotes accumulate polyhydroxybutyrate (PHB) intracellularly as a storage material. It has also been proposed that PHB accumulation improves bacterial stress resistance. Cupriavidus necator and its PHB non-accumulating mutant were employed to investigate the protective role of PHB under hypertonic conditions. The presence of PHB granules enhanced survival of the bacteria after exposure to hypertonic conditions. Surprisingly, when coping with such conditions, the bacteria did not utilize PHB to harvest carbon or energy, suggesting that, in the osmotic upshock of C. necator, the protective mechanism of PHB granules is not associated with their hydrolysis. The presence of PHB granules influenced the overall properties of the cells, since challenged PHB-free cells underwent massive plasmolysis accompanied by damage to the cell membrane and the leakage of cytoplasm content, while no such effects were observed in PHB containing bacteria. Moreover, PHB granules demonstrated "liquid-like" properties indicating that they can partially repair and stabilize cell membranes by plugging small gaps formed during plasmolysis. In addition, the level of dehydration and changes in intracellular pH in osmotically challenged cells were less pronounced for PHB-containing cultures, demonstrating the important role of PHB for bacterial survival under hyperosmotic conditions.

• MeSH
• časové faktory MeSH
• Cupriavidus necator cytologie   účinky léků   metabolismus   ultrastruktura   MeSH
• cytoplazmatická granula účinky léků   metabolismus   ultrastruktura   MeSH
• elektronová kryomikroskopie MeSH
• fluoresceiny metabolismus   MeSH
• fluorescenční mikroskopie MeSH
• hydroxybutyráty metabolismus   MeSH
• hypertonické roztoky farmakologie   MeSH
• krystalizace MeSH
• mikrobiální viabilita účinky léků   MeSH
• osmotický tlak účinky léků   MeSH
• termogravimetrie MeSH
• voda MeSH
• Publikační typ
• časopisecké články MeSH

OBJECTIVES: Our previous experiments proved that methylprednisolone (MP) can significantly reduce axonal impairment accompanying extracellular oedema induced by the osmotic challenge (load) on the blood-brain barrier (BBB). The aim of the present work was to identify whether MP can affect myelin impairment accompanying intracellular oedema induced by water intoxication. METHODS: For induction of cellular brain oedema, the standard model of water intoxication was chosen. Animals received distilled water in amount corresponding to 15% of the animal's body weight. The volume was divided into three parts and administered intraperitoneally in 8 hours interval. Axonal changes were recognized as signs of myelin disintegration (oedematous distensions, axonal swelling, vesicles, varicosities) at histological sections stained with Black Gold and classified into four grades of myelin degradation. Hippocampal CA1 and CA3 areas and the dentate gyrus were selected for the study. Methylprednisolone was administered either intraperitoneally or intracarotically. Its effect was studied in two different time intervals: in the acute group (30 minutes after hyperhydration and MP application) and in chronic one (1 week after hyperhydration and MP application). Results: In both the acute and chronic groups, cellular oedema induced by water intoxication brought about apparent damage of myelin (compared to control animals p<0.0001). Intracarotic injection of MP was not able to influence myelin integrity changes either in the acute or in chronic group. However, intraperitoneal administration of MP increased the level of myelin deterioration in the acute group (p 0.05), but improved myelin changes in the chronic group (p<0.005). Conclusion: The effect of MP on axonal impairment during cellular brain oedema induced by water intoxication differs from that during the extracellular osmotic oedema. In the extracellular oedema, cellular metabolism is not significantly affected and myelin changes can be influenced by the neuroprotective effect of MP. The primary cause of cellular oedema is a disorder of cellular metabolism and myelin impairment is one of the structural consequences of such disorder. That is why the myelin changes are not affected by MP administration in a consistent and specific manner.

• MeSH
• axony účinky léků   metabolismus   patologie   MeSH
• edém mozku farmakoterapie   metabolismus   patologie   MeSH
• glukokortikoidy farmakologie   MeSH
• hematoencefalická bariéra účinky léků   metabolismus   patologie   MeSH
• intoxikace vodou farmakoterapie   metabolismus   patologie   MeSH
• krysa rodu rattus MeSH
• methylprednisolon farmakologie   MeSH
• myelinová pochva účinky léků   metabolismus   patologie   MeSH
• nervová vlákna myelinizovaná účinky léků   metabolismus   patologie   MeSH
• neuroprotektivní látky farmakologie   MeSH
• osmotický tlak účinky léků   MeSH
• potkani Wistar MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Despite significant advances in their molecular pathogenesis, skeletal vascular tumors remain diagnostically challenging due to their aggressive radiologic appearance and significant morphologic overlap. Within the epithelioid category and at the benign end of the spectrum, recurrent FOS/FOSB fusions have defined most epithelioid hemangiomas, distinguishing them from epithelioid hemangioendothelioma and angiosarcoma. More recently, the presence of EWSR1/FUS :: NFATC1/2 fusions emerged as the genetic hallmark of a novel group of unusual vascular proliferations, often displaying epithelioid morphology, with alternating vasoformative and solid growth, variable atypia, reminiscent of composite hemangioendothelioma. In this study, we further our understanding and morphologic spectrum of NFATC -fusion positive vascular neoplasms by describing 9 new cases, including soft tissue locations and novel fusion partners. Combining with the initial cohort of 5 cases, a total of 14 patients were analyzed, showing slight female predilection and an age range of 10 to 66 (mean 42 y). Twelve patients had solitary lesions, while 2 had multifocal polyostotic (pelvic bones) disease. Overall, 12 lesions were intra-osseous and 2 in soft tissue. By targeted RNA Fusion panels or FISH, there were 6 cases of EWSR1::NFATC1 , 4 EWSR1::NFATC2 , 2 FUS::NFATC2 , 1 EWSR1 rearrangement, and 1 with a novel FABP4::NFATC2 fusion. Follow-up was available in 4 patients. One patient experienced 2 local recurrences, 11 and 15 years postdiagnosis, and one patient experienced progressive disease despite multimodality treatment (curettings, embolization, radiation) over 3 years. In summary, our extended investigation confirms that NFATC -related fusions define a distinct group of vascular neoplasms with variable architecture, epithelioid phenotype, and cytologic atypia, commonly located in the bone, occasionally multifocal and with potential for local recurrence and aggressive behavior but no metastatic potential. Molecular analysis is recommended in diagnostically challenging cases with atypical histology to exclude malignancy.

• MeSH
• epiteloidní hemangioendoteliom * patologie   MeSH
• hemangioendoteliom * MeSH
• hemangiom * MeSH
• lidé MeSH
• transkripční faktory NFATC genetika   MeSH
• transkripční faktory genetika   MeSH
• vaskulární nádory * genetika   terapie   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH