Light modulation
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EJC supplements, ISSN 1359-6349 vol. 4, suppl. 7, July 2006
20 s. : il., tab. ; 28 cm
- MeSH
- antimitotika farmakologie terapeutické užití MeSH
- mikrotubulární proteiny účinky léků MeSH
- modulátory tubulinu MeSH
- nádory imunologie MeSH
- Publikační typ
- sborníky MeSH
- Konspekt
- Farmacie. Farmakologie
- NLK Obory
- onkologie
- farmacie a farmakologie
- cytologie, klinická cytologie
Biological effects of high fluence low-power (HFLP) lasers have been reported for some time, yet the molecular mechanisms procuring cellular responses remain obscure. A better understanding of the effects of HFLP lasers on living cells will be instrumental for the development of new experimental and therapeutic strategies. Therefore, we investigated sub-cellular mechanisms involved in the laser interaction with human hepatic cell lines. We show that mitochondria serve as sub-cellular "sensor" and "effector" of laser light non-specific interactions with cells. We demonstrated that despite blue and red laser irradiation results in similar apoptotic death, cellular signaling and kinetic of biochemical responses are distinct. Based on our data, we concluded that blue laser irradiation inhibited cytochrome c oxidase activity in electron transport chain of mitochondria. Contrary, red laser triggered cytochrome c oxidase excessive activation. Moreover, we showed that Bcl-2 protein inhibited laser-induced toxicity by stabilizing mitochondria membrane potential. Thus, cells that either overexpress or have elevated levels of Bcl-2 are protected from laser-induced cytotoxicity. Our findings reveal the mechanism how HFLP laser irradiation interfere with cell homeostasis and underscore that such laser irradiation permits remote control of mitochondrial function in the absence of chemical or biological agents.
- MeSH
- apoptóza účinky záření MeSH
- buňky Hep G2 MeSH
- fototerapie * MeSH
- laserová terapie s nízkou intenzitou světla * MeSH
- lidé MeSH
- membránový potenciál mitochondrií genetika účinky záření MeSH
- mitochondriální membrány metabolismus účinky záření MeSH
- mitochondrie genetika účinky záření MeSH
- oxidace-redukce účinky záření MeSH
- reaktivní formy kyslíku metabolismus MeSH
- regulace genové exprese účinky záření MeSH
- respirační komplex IV genetika MeSH
- transport elektronů genetika účinky záření MeSH
- viabilita buněk genetika účinky záření MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Plant survival in temperate zones requires efficient cold acclimation, which is strongly affected by light and temperature signal crosstalk, which converge in modulation of hormonal responses. Cold under low light conditions affected Arabidopsis responses predominantly in apices, possibly because energy supplies were too limited for requirements of these meristematic tissues, despite a relatively high steady-state quantum yield. Comparing cold responses at optimal light intensity and low light, we found activation of similar defence mechanisms-apart from CBF1-3 and CRF3-4 pathways, also transient stimulation of cytokinin type-A response regulators, accompanied by fast transient increase of trans-zeatin in roots. Upregulated expression of components of strigolactone (and karrikin) signalling pathway indicated involvement of these phytohormones in cold responses. Impaired response of phyA, phyB, cry1 and cry2 mutants reflected participation of these photoreceptors in acquiring freezing tolerance (especially cryptochrome CRY1 at optimal light intensity and phytochrome PHYA at low light). Efficient cold acclimation at optimal light was associated with upregulation of trans-zeatin in leaves and roots, while at low light, cytokinin (except cis-zeatin) content remained diminished. Cold stresses induced elevation of jasmonic acid and salicylic acid (in roots). Low light at optimal conditions resulted in strong suppression of cytokinins, jasmonic and salicylic acid.
Spatial light modulators have become an essential tool for advanced microscopy, enabling breakthroughs in 3D, phase, and super-resolution imaging. However, continuous spatial-light modulation that is capable of capturing sub-millisecond microscopic motion without diffraction artifacts and polarization dependence is challenging. Here we present a photothermal spatial light modulator (PT-SLM) enabling fast phase imaging for nanoscopic 3D reconstruction. The PT-SLM can generate a step-like wavefront change, free of diffraction artifacts, with a high transmittance and a modulation efficiency independent of light polarization. We achieve a phase-shift > π and a response time as short as 70 µs with a theoretical limit in the sub microsecond range. We used the PT-SLM to perform quantitative phase imaging of sub-diffractional species to decipher the 3D nanoscopic displacement of microtubules and study the trajectory of a diffusive microtubule-associated protein, providing insights into the mechanism of protein navigation through a complex microtubule network.
- MeSH
- časové faktory MeSH
- interferenční mikroskopie metody statistika a číselné údaje MeSH
- kovové nanočástice ultrastruktura MeSH
- lidé MeSH
- mikroskopie atomárních sil MeSH
- mikroskopie fázově kontrastní metody statistika a číselné údaje MeSH
- mikrotubuly metabolismus ultrastruktura MeSH
- nanotechnologie MeSH
- nanotrubičky ultrastruktura MeSH
- optické jevy MeSH
- počítačová simulace MeSH
- proteiny asociované s mikrotubuly metabolismus MeSH
- proteiny buněčného cyklu metabolismus MeSH
- Schizosaccharomyces pombe - proteiny metabolismus MeSH
- světlo MeSH
- tubulin metabolismus MeSH
- zlato MeSH
- zobrazování trojrozměrné metody statistika a číselné údaje MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The regulation of fungicidal and hydrolytic enzyme activity was investigated in a set of cyanobacterial strains belonging to the genus Anabaena (Anabaena laxa RPAN8, Anabaena iyengarii RPAN9, Anabaena variabilis RPAN59 and Anabaena oscillarioides RPAN69), with A. variabilis RPAN16 serving as negative control. Time course studies undertaken with cultures incubated under different light and temperature conditions revealed enhancement in growth and fungicidal activity under continuous light (CL) and light dark (LD, 16:8) conditions and temperature of 30 °C and 40 °C. A significant increase of 3-18 % in chitosanase activity was recorded in all the 4-week-old cultures under CL condition and at 40 °C. Endoglucanase activity of RPAN8 and 9 was twofolds higher than the other strains under all light/dark conditions and temperature in the 4-week-old cultures, while continuous dark (CD) enhanced CMCase activity in RPAN69. This study provided useful information regarding the most suitable conditions of light and temperature for maximizing hydrolytic enzyme activity and fungicidal activity, as a prelude to their effective use as biocontrol agents.
Cytokinins are an important group of plant hormones that are also found in other organisms, including cyanobacteria. While various aspects of cytokinin function and metabolism are well understood in plants, the information is limited for cyanobacteria. In this study, we first experimentally confirmed a prenylation of tRNA by recombinant isopentenyl transferase NoIPT2 from Nostoc sp. PCC 7120, whose encoding gene we previously identified in Nostoc genome along with the gene for adenylate isopentenyl transferase NoIPT1. In contrast to NoIPT2, the transcription of NoIPT1 was strongly activated during the dark period and was followed by an increase in the cytokinin content several hours later in the light period. Dominant cytokinin metabolites detected at all time points were free bases and monophosphates of isopentenyladenine and cis-zeatin, while N-glucosides were not detected at all. Whole transcriptome differential expression analysis of cultures of the above Nostoc strain treated by cytokinin compared to untreated controls indicated that cytokinin together with light trigger expression of several genes related to signal transduction, including two-component sensor histidine kinases and two-component hybrid sensors and regulators. One of the affected histidine kinases with a cyclase/histidine kinase-associated sensory extracellular domain similar to the cytokinin-binding domain in plant cytokinin receptors was able to modestly bind isopentenyladenine. The data show that the genetic disposition allows Nostoc not only to produce free cytokinins and prenylate tRNA but also modulate the cytokinin biosynthesis in response to light, triggering complex changes in sensing and regulation.
Metastazující maligní melanom se řadí mezi nejobtížněji léčitelné diagnózy s mediánem přežití mezi 6 a 9 měsíci. Přežití 5 a více let se uvádí pouze v 1–2 % případů. Ročně umírá v ČR na melanom téměř 350 osob. Na první pohled se toto číslo nezdá dramatické, ale značně nabývá na významu při skutečnosti, že se jedná obvykle o jedince v produktivním věku. Dosavadním standardem léčby, který slouží k hodnocení účinnosti nových preparátů, je již 35 let dakarbazin, jehož léčebná odpověď se pohybuje v rozmezí 15–20 %. Výsledky klinických studií posledních dvou let zásadně změnily přístup k léčbě metastazujícího melanomu. Jako účinné se ukázaly dva směry, které jsou ve své biologické podstatě zcela odlišné: léčba imunomodulační zaměřená na aktivaci T-lymfocytů (a celého imunitního systému) a léčba cílená zaměřená na blokaci mutace genů v melanomu. Ipilimumab, monoklonální protilátka namířená proti antigenu CTLA-4, dokázal jako první molekula v historii statisticky signifikantně prodloužit celkové přežívání pacientů s metastazujícím melanomem.
Metastatic malignant melanoma is one of the cancers that are most difficult to treat, with a median survival ranging from six to nine months. The reported five-year or longer survival rates are 1-2 %. Melanoma accounts for nearly 350 deaths in the Czech Republic each year. At first sight, this number does not seem dramatic, but it becomes considerably more significant in the light of the fact that most deaths occur in the productive age group. Dacarbazine that has been the standard first-line therapy for 35 years and serves as a reference in testing novel drugs induces therapeutic response in 15-20 % of patients. The results of clinical trials obtained over the last two years have substantially changed the therapeutic approach to metastatic melanoma. Two therapeutic strategies differing in their biological nature have proved effective: immune modulation leading to activation of T-lymphocytes (and of the immune system in general) and therapy targeting the gene mutation in melanoma.
- Klíčová slova
- anti-CTLA-4, gen BRAF,
- MeSH
- antigen CTLA-4 imunologie terapeutické užití MeSH
- imunomodulace MeSH
- ipilimumab MeSH
- lidé MeSH
- melanom farmakoterapie imunologie MeSH
- metastázy nádorů MeSH
- monoklonální protilátky imunologie škodlivé účinky terapeutické užití MeSH
- protilátky nádorové imunologie škodlivé účinky terapeutické užití MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- záchranná terapie MeSH
- Check Tag
- lidé MeSH
