A novel method for semiautomated assessment of directions of collagen fibers in soft tissues using histological image analysis is presented. It is based on multiple rotated images obtained via polarized light microscopy without any additional components, i.e., with just two polarizers being either perpendicular or nonperpendicular (rotated). This arrangement breaks the limitation of 90° periodicity of polarized light intensity and evaluates the in-plane fiber orientation over the whole 180° range accurately and quickly. After having verified the method, we used histological specimens of porcine Achilles tendon and aorta to validate the proposed algorithm and to lower the number of rotated images needed for evaluation. Our algorithm is capable to analyze 5·105 pixels in one micrograph in a few seconds and is thus a powerful and cheap tool promising a broad application in detection of collagen fiber distribution in soft tissues.

• MeSH
• Achillova šlacha metabolismus   MeSH
• algoritmy MeSH
• extracelulární matrix metabolismus   MeSH
• kolagen metabolismus   MeSH
• mikroskopie metody   MeSH
• optické zobrazování metody   MeSH
• počítačové zpracování obrazu metody   MeSH
• polarizační mikroskopie metody   MeSH
• prasata MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The fluorescent molecule diphenylhexatriene (DPH) has been often used in combination with fluorescence anisotropy measurements, yet little is known regarding the non-linear optical properties. In the current work, we focus on them and extend the application to fluorescence, while paying attention to the conformational versatility of DPH when it is embedded in different membrane phases. Extensive hybrid quantum mechanics/molecular mechanics calculations were performed to investigate the influence of the phase- and temperature-dependent lipid environment on the probe. Already, the transition dipole moments and one-photon absorption spectra obtained in the liquid ordered mixture of sphingomyelin (SM)-cholesterol (Chol) (2:1) differ largely from the ones calculated in the liquid disordered DOPC and solid gel DPPC membranes. Throughout the work, the molecular conformation in SM:Chol is found to differ from the other environments. The two-photon absorption spectra and the ones obtained by hyper-Rayleigh scattering depend strongly on the environment. Finally, a stringent comparison of the fluorescence anisotropy decay and the fluorescence lifetime confirm the use of DPH to gain information upon the surrounding lipids and lipid phases. DPH might thus open the possibility to detect and analyze different biological environments based on its absorption and emission properties.

• MeSH
• cholesterol chemie   MeSH
• difenylhexatrien chemie   MeSH
• fluorescenční barviva chemie   MeSH
• fluorescenční polarizace MeSH
• lipidové dvojvrstvy chemie   MeSH
• molekulární konformace MeSH
• sfingomyeliny chemie   MeSH
• simulace molekulární dynamiky MeSH
• tranzitní teplota MeSH
• vztahy mezi strukturou a aktivitou MeSH
• změna skupenství MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• nádory radioterapie   MeSH
• nukleární lékařství metody   MeSH
• radioterapie metody   MeSH
• Publikační typ
• učebnice MeSH

• Konspekt
• Učební osnovy. Vyučovací předměty. Učebnice
• Lékařské vědy. Lékařství
• NLK Obory
• radiologie, nukleární medicína a zobrazovací metody
• onkologie
• NLK Publikační typ
• kolektivní monografie

We tested the potential of a miniaturized Raman spectrometer for use in field detection of snow algae pigments. A miniature Raman spectrometer, equipped with an excitation laser at 532 nm, allowed for the detection of carotenoids in cells of Chloromonas nivalis and Chlamydomonas nivalis at different stages of their life cycle. Astaxanthin, the major photoprotective pigment, was detected in algal blooms originating in snows at two alpine European sites that differed in altitude (Krkonoše Mts., Czech Republic, 1502 m a.s.l., and Ötztal Alps, Austria, 2790 m a.s.l.). Comparison is made with a common microalga exclusively producing astaxanthin (Haematococcus pluvialis). The handheld Raman spectrometer is a useful tool for fast and direct field estimations of the presence of carotenoids (mainly astaxanthin) within blooms of snow algae. Application of miniature Raman instruments as well as flight prototypes in areas where microbes are surviving under extreme conditions is an important stage in preparation for successful deployment of this kind of instrumentation in the framework of forthcoming astrobiological missions to Mars. Key Words: Snow algae-Chloromonas nivalis-Chlamydomonas nivalis-On-site field detection-Raman spectroscopy-Astaxanthin. Astrobiology 16, 913-924.

• MeSH
• Chlamydomonas chemie   MeSH
• Chlorophyta chemie   MeSH
• karotenoidy analýza   MeSH
• ledový příkrov MeSH
• miniaturizace přístrojové vybavení   MeSH
• Ramanova spektroskopie přístrojové vybavení   MeSH
• sníh mikrobiologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH

• MeSH
• biochemie MeSH
• chemie MeSH
• organická chemie MeSH

• Konspekt
• Chemie. Mineralogické vědy
• NLK Obory
• chemie, klinická chemie
• NLK Publikační typ
• kolektivní monografie

• MeSH
• buňky * MeSH
• molekulární biologie MeSH

• Konspekt
• Biochemie. Molekulární biologie. Biofyzika
• NLK Obory
• molekulární biologie, molekulární medicína
• NLK Publikační typ
• učebnice vysokých škol

ArcLight, a genetically encoded fluorescent protein voltage probe with a large ΔF/ΔV, is a fusion between the voltage sensing domain of the Ciona instestinalis voltage sensitive phosphatase and super ecliptic pHluorin carrying a single mutation (A227D in the fluorescent protein). Without this mutation the probe produces only a very small change in fluorescence in response to voltage deflections (∼ 1%). The large signal afforded by this mutation allows optical detection of action potentials and sub-threshold electrical events in single-trials in vitro and in vivo. However, it is unclear how this single mutation produces a probe with such a large modulation of its fluorescence output with changes in membrane potential. In this study, we identified which residues in super ecliptic pHluorin (vs eGFP) are critical for the ArcLight response, as a similarly constructed probe based on eGFP also exhibits large response amplitude if it carries these critical residues. We found that D147 is responsible for determining the pH sensitivity of the fluorescent protein used in these probes but by itself does not result in a voltage probe with a large signal. We also provide evidence that the voltage dependent signal of ArcLight is not simply sensing environmental pH changes. A two-photon polarization microscopy study showed that ArcLight's response to changes in membrane potential includes a reorientation of the super ecliptic pHluorin. We also explored different changes including modification of linker length, deletion of non-essential amino acids in the super ecliptic pHluorin, adding a farnesylation site, using tandem fluorescent proteins and other pH sensitive fluorescent proteins.

• MeSH
• akční potenciály * MeSH
• aminokyseliny chemie   genetika   metabolismus   MeSH
• fluorescence MeSH
• fluorescenční barviva chemie   metabolismus   MeSH
• fluorescenční spektrometrie MeSH
• HEK293 buňky MeSH
• kinetika MeSH
• koncentrace vodíkových iontů MeSH
• konfokální mikroskopie MeSH
• krysa rodu rattus MeSH
• kultivované buňky MeSH
• lidé MeSH
• luminescentní proteiny chemie   genetika   metabolismus   MeSH
• membránové potenciály MeSH
• metoda terčíkového zámku MeSH
• missense mutace MeSH
• neurony metabolismus   fyziologie   MeSH
• prenylace MeSH
• rekombinantní fúzní proteiny chemie   genetika   metabolismus   MeSH
• zelené fluorescenční proteiny chemie   genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, American Recovery and Reinvestment Act MeSH
• Research Support, N.I.H., Extramural MeSH

• MeSH
• biofyzika MeSH

• Konspekt
• Biochemie. Molekulární biologie. Biofyzika
• Učební osnovy. Vyučovací předměty. Učebnice
• NLK Obory
• fyzika, biofyzika
• NLK Publikační typ
• učebnice vysokých škol

Little is known about the viability of myxozoan actinospore stages after harvest from laboratory cultures of infected oligochaete worms. The viability and reactivity of actinospores of three myxozoan species was evaluated after short-term storage at 4°C and 12°C. Two methods of determining actinospore viability were compared: differential fluorescent staining and direct microscopic observation of morphological indicators of spore integrity. Spore reactivity was quantified by measuring polar filament discharge rates in a micro-assay with fish mucus substrate and mechanical stimulation by vibration. The age-dependent viability of the three species showed clear differences. Myxobolus cerebralis actinospores had the shortest effective life span whereas Henneguya nuesslini actinospores survived significantly longer. Storage at lower temperatures yielded higher viability in all species. Myxobolus pseudodispar actinospores were significantly robust up to 12°C when assessed by staining, but showed similar viability characteristics as H. nuesslini when analyzed morphologically. Evaluation of spore viability by fluorescent staining correlated with morphological assessment, although fewer viable actinospores were usually detected microscopically. Polar filament discharge activity of morphologically intact actinospores did not significantly decrease until the third day of storage compared to freshly harvested samples. The results indicate that durability and reactivity trends during storage of actinospores differ among myxozoan species.

• MeSH
• analýza přežití MeSH
• barvení a značení metody   MeSH
• Cnidaria cytologie   fyziologie   metabolismus   MeSH
• fluorescence MeSH
• mikroskopie MeSH
• nízká teplota MeSH
• Oligochaeta parazitologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH

The pathophysiology of microcirculation is intensively investigated to understand disease development at the microscopic level. Orthogonal polarization spectral (OPS) imaging and its successor sidestream dark-field (SDF) imaging are relatively new noninvasive optical techniques allowing direct visualization of microcirculation in both clinical and experimental studies. The goal of this experimental study was to describe basic microcirculatory parameters of skeletal muscle and ileal serous surface microcirculation in the rat using SDF imaging and to standardize the technical aspects of the protocol. Interindividual variability in functional capillary density (FCD) and small vessels (<25 microm in diameter) proportion was determined in anesthetized rats on the surface of quadriceps femoris (m. rectus femoris and m. vastus medialis) and serous surface of ileum. Special custom made flexible arm was used to fix the SDF probe minimizing the pressure movement artifacts. Clear high contrast images were analyzed off-line. The mean FCD obtained from the surface of skeletal muscle and ileal serous surface was 219 (213-225 cm/cm(2)) and 290 (282-298 cm/cm(2)) respectively. There was no statistically significant difference between rats in mean values of FCD obtained from the muscle (P = 0.273) in contrast to ileal serous surface, where such difference was statistically significant (P = 0.036). No statistically significant differences in small vessels percentage was detected on either the muscle surface (P = 0.739) or on ileal serous surface (P = 0.659). Our study has shown that interindividual variability of basic microcirculatory parameters in rat skeletal muscle and ileum is acceptable when using SDF imaging technique according to a highly standardized protocol and with appropriate fixation device. SDF imaging represents promising technology for experimental and clinical studies.

• MeSH
• čtyřhlavý sval stehenní krevní zásobení   MeSH
• financování organizované MeSH
• ileum krevní zásobení   MeSH
• krysa rodu rattus MeSH
• mikrocirkulace MeSH
• polarizační mikroskopie metody   normy   MeSH
• potkani Wistar MeSH
• reprodukovatelnost výsledků MeSH
• serózní membrána krevní zásobení   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH