The key to obtaining an optimum performance of an enzyme is often a question of devising a suitable enzyme and optimisation of conditions for its immobilization. In this study, laccases from the native isolates of white rot fungi Fomes fomentarius and/or Trametes versicolor, obtained from Czech forests, were used. From these, cross-linked enzyme aggregates (CLEA) were prepared and characterised when the experimental conditions were optimized. Based on the optimization steps, saturated ammonium sulphate solution (75 wt.%) was used as the precipitating agent, and different concentrations of glutaraldehyde as a cross-linking agent were investigated. CLEA aggregates formed under the optimal conditions showed higher catalytic efficiency and stabilities (thermal, pH, and storage, against denaturation) as well as high reusability compared to free laccase for both fungal strains. The best concentration of glutaraldehyde seemed to be 50 mM and higher efficiency of cross-linking was observed at a low temperature 4 °C. An insignificant increase in optimum pH for CLEA laccases with respect to free laccases for both fungi was observed. The results show that the optimum temperature for both free laccase and CLEA laccase was 35 °C for T. versicolor and 30 °C for F. fomentarius. The CLEAs retained 80% of their initial activity for Trametes and 74% for Fomes after 70 days of cultivation. Prepared cross-linked enzyme aggregates were also investigated for their decolourisation activity on malachite green, bromothymol blue, and methyl red dyes. Immobilised CLEA laccase from Trametes versicolor showed 95% decolourisation potential and CLEA from Fomes fomentarius demonstrated 90% decolourisation efficiency within 10 h for all dyes used. These results suggest that these CLEAs have promising potential in dye decolourisation.

• MeSH
• azosloučeniny chemie   MeSH
• barva MeSH
• barvicí látky chemie   MeSH
• bromthymolová modř chemie   MeSH
• enzymy imobilizované chemie   MeSH
• glutaraldehyd chemie   MeSH
• katalýza MeSH
• lakasa chemie   MeSH
• Polyporales enzymologie   MeSH
• reagencia zkříženě vázaná chemie   MeSH
• rosanilinová barviva chemie   MeSH
• síran amonný chemie   MeSH
• teplota MeSH
• Trametes enzymologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The study of experimental design conjunction with artificial neural networks for optimisation of isocratic ion-pair reverse phase HPLC separation of neuroprotective peptides is reported. Different types of experimental designs (full-factorial, fractional) were studied as suitable input and output data sources for ANN training and examined on mixtures of humanin derivatives. The independent input variables were: composition of mobile phase, including its pH, and column temperature. In case of a simple mixture of two peptides, the retention time of the most retentive component and resolution were used as the dependent variables (outputs). In case of a complex mixture with unknown number of components, number of peaks, sum of resolutions and retention time of ultimate peak were considered as output variables. Fractional factorial experimental design has been proved to produce sufficient input data for ANN approximation and thus further allowed decreasing the number of experiments necessary for optimisation. After the optimal separation conditions were found, fractions with peptides were collected and their analysis using off-line matrix assisted laser desorption/ionisation time of flight mass spectrometry (MALDI-TOF-MS) was performed.

• MeSH
• chemická frakcionace metody   MeSH
• financování organizované MeSH
• intracelulární signální peptidy a proteiny genetika   izolace a purifikace   MeSH
• neuronové sítě MeSH
• spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
• substituce aminokyselin MeSH
• vysokoúčinná kapalinová chromatografie metody   MeSH

Incubation is an energetically demanding process during which birds apply heat to their eggs to ensure embryonic development. Parent behaviours such as egg turning and exchanging the outer and central eggs in the nest cup affect the amount of heat lost to the environment from individual eggs. Little is known, however, about whether and how egg surface temperature and cooling rates vary among the different areas of an egg and how the arrangement of eggs within the clutch influences heat loss. We performed laboratory (using Japanese quail eggs) and field (with northern lapwing eggs) experiments using infrared imaging to assess the temperature and cooling patterns of heated eggs and clutches. We found that (i) the sharp poles of individual quail eggs warmed to a higher egg surface temperature than did the blunt poles, resulting in faster cooling at the sharp poles compared to the blunt poles; (ii) both quail and lapwing clutches with the sharp poles oriented towards the clutch centre (arranged clutches) maintained higher temperatures over the central part of the clutch than occurred in those clutches where most of the sharp egg poles were oriented towards the exterior (scattered clutches); and (iii) the arranged clutches of both quail and lapwing showed slower cooling rates at both the inner and outer clutch positions than did the respective parts of scattered clutches. Our results demonstrate that egg surface temperature and cooling rates differ between the sharp and blunt poles of the egg and that the orientation of individual eggs within the nest cup can significantly affect cooling of the clutch as a whole. We suggest that birds can arrange their eggs within the nest cup to optimise thermoregulation of the clutch.

• MeSH
• biologické modely MeSH
• Charadriiformes fyziologie   MeSH
• Coturnix fyziologie   MeSH
• hnízdění fyziologie   MeSH
• povrchové vlastnosti MeSH
• teplota * MeSH
• vaječná skořápka fyziologie   MeSH
• vejce * MeSH
• velikost snůšky MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Biological experiments involving isolated organs and tissues demand precise temperature monitoring and regulation. An automatic temperature control system was proposed and optimised on real isolated swine hearts and the prototype is described in this work. The traditional Langendorff apparatus consists of a heart holder, a reservoir of perfusion solution flowing to aortic cannula and a heating bath allowing passive heat transfer to the reservoir of perfusion solution. The commercial infrared camera FLIR T62101 was added to this basic set-up and used for very precise monitoring of the temperature kinetic of the organ and connected with an electronic feedback loop, which allowed real-time and precise regulation of heat transfer from the heating bath to the perfusion solution and in turn indirectly to the heart tissue. This provides real time control and active regulation of the myocardial tissue temperature. The infrared camera was tested in several modes and several variants of detection were optimised for ideal measurement of the region of interest of the ex vivo organ. The kinetics of the temperature changes and temperature stability of the tissue were recorded and calibrated by external electronic thermometers (type Pt100, inserted in tissue). The time lapse from the hang-up of the hypo termed organ (30 °C) until optimal warming (37 °C) was less than eight minutes in the final instrument prototype. The final stability of the 37 °C tissue temperature was approved; the temperature fluctuation of left ventricle tissue was characterised as 36.8 ± 0.5 °C. This upgraded traditional instrument could be used in specific preclinical and clinical transplantation and analytical projects in future.

• MeSH
• infračervené záření MeSH
• lidé MeSH
• preparace izolovaného srdce * metody   MeSH
• terapeutické zahřívání metody   přístrojové vybavení   MeSH
• termoregulace MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH

Parasites alter their host behaviour and vice versa as a result of mutual adaptations in the evolutionary arms race. One of these adaptations involves changes in host thermoregulation, which has the potential to harm the parasite and thereby act as a defence mechanism. We used a model of the brown trout (Salmo trutta) experimentally parasitised with glochidia ectoparasitic larvae from the endangered freshwater pearl mussel (Margaritifera margaritifera) to reveal whether parasitisation alters fish behavioural thermoregulation. A study using radiotelemetry temperature sensors was performed during almost one year of the M. margaritifera parasitic stage. Glochidia-infested S. trutta altered their thermoregulation through active searching for habitats with different thermal regimes. The general preference for temperatures in infested fish varied and was either above or below the temperature preferred by uninfested individuals. Infested fish also preferred different temperatures across localities, whereas uninfested fish maintained their thermal preference no matter which stream they inhabited. Glochidia further induced the expression of a behavioural syndrome among S. trutta personality traits, suggesting that it might increase the probability that the fish host would occur in the glochidia temperature optimum. Our findings present the first evidence that thermoregulation plays a fundamental role in the relationship of affiliated mussels and their fish hosts. Incorporating thermoregulation as a factor in the study of this relationship can help to interpret results from previous behavioural studies, as well as to optimise management measures related to endangered mussels.

• MeSH
• aklimatizace MeSH
• interakce hostitele a parazita MeSH
• larva růst a vývoj   fyziologie   MeSH
• mlži růst a vývoj   fyziologie   MeSH
• nemoci ryb parazitologie   MeSH
• pstruh * MeSH
• termoregulace * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Hibernating bats optimise the duration of torpor bouts and arousals in relation to hibernaculum microclimatic conditions and fat reserves. Clustering has significant physiological and ecological benefits, promoting successful hibernation of individuals. Such aggregations may help maintain optimal temperatures, allowing better energy utilisation than in solitarily bats. However, aroused bats in a cluster could conceivably disturb those still hibernating, starting an energy-demanding arousal process. Our study was conducted over two winters in two different hibernacula (cave and mine) in the Czech Republic, where Greater mouse-eared bats (Myotis myotis) have previously been diagnosed with white-nose syndrome. In 118 arousal episodes we recorded 193 individual arousals in which a warming phase was observed, 135 (69.9%) being cold arousals, where bats ceased increasing their body temperatures at ≤ 10 °C. The remaining arousals were standard normothermic arousals, where body (fur) surface temperatures reached > 20 °C. Cold arousals occurred during the mid- and late hibernation periods, suggesting they were a response to disturbance by a neighbour in the same cluster. Arousal cascades, where bats aroused in series, were rare (12.7%) and reached a maximum in mid-January. Our data suggest that Myotis bats prolong their torpor bouts using numerous cold arousals but few arousal cascades. Upon arrival of a bat, the clustered bats show tolerance to disturbing by conspecifics.

• MeSH
• arousal MeSH
• Chiroptera fyziologie   MeSH
• chování zvířat MeSH
• hibernace * MeSH
• nízká teplota MeSH
• roční období MeSH
• strnulost MeSH
• tělesná teplota MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: The species of the Hypericum genus are markedly variable in morphological, physiological and biochemical traits. They significantly differ in their area of distribution, which may determine their natural tolerance to environmental conditions, such as temperature extremes. OBJECTIVE: To test the hypothesis that the species growing worldwide in different regions and altitudes would be better able to withstand cryopreservation than the endemics. METHODS: The frost tolerance of 10 selected Hypericum species was evaluated. A possible stimulatory effect of cold-acclimation and vitrification-associated stressors on the content of hypericins was also investigated RESULTS: We found that frost tolerance of 10 selected Hypericum species expressed by LT50 ranged between -11 degree C for the species occurring worldwide and -4 degree C for sub/tropical frost sensitive taxons which corresponded with their natural habitats. CONCLUSIONS: Although the mean recoveries for all species cryopreserved with the same vitrification procedure did not exceed 30%, the effect of genetic predisposition to cold tolerance should be considered for optimisation of cryopreservation protocol. Our data neither proved an elicitation effect of cold on hypericin biosynthesis, nor correlation between hypericin content and quantitative characteristics of the hypericin-accumulating black nodules.

• MeSH
• aklimatizace MeSH
• druhová specificita MeSH
• kryoprezervace MeSH
• nadmořská výška MeSH
• nízká teplota MeSH
• třezalka fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND: The cooling efficacy of intravenous administration of cold crystalloids can be enhanced by optimisation of the procedure. This study assessed the temperature stability of different application regimens of cold normal saline (NS) in simulated prehospital conditions. METHODS: Twelve different application regimens of 4 °C cold NS (volumes of 250, 500 and 1000 ml applied at infusion rates of 1000, 2000, 4000 and 6000 ml/h) were investigated for infusion temperature changes during administration to an artificial detention reservoir in simulated prehospital conditions. RESULTS: An increase in infusion temperature was observed in all regimens, with an average of 8.1 ± 3.3 °C (p<0.001). This was most intense during application of the residual 20% of the initial volume. The lowest rewarming was exhibited in regimens with 250 and 500 ml bags applied at an infusion rate of 6000 ml/h and 250 ml applied at 4000 ml/h. More intense, but clinically acceptable, rewarming presented in regimens with 500 and 1000 ml bags administered at 4000 ml/h, 1000 ml at 6000 ml/h and 250 ml applied at 2000 ml/h. Other regimens were burdened by excessive rewarming. CONCLUSION: Rewarming of cold NS during application in prehospital conditions is a typical occurrence. Considering that the use of 250 ml bags means the infusion must be exchanged too frequently during cooling, the use of 500 or 1000 ml NS bags applied at an infusion rate of ≥4000 ml/h and termination of the infusion when 80% of the infusion volume has been administered is regarded as optimal.

• MeSH
• chlorid sodný aplikace a dávkování   MeSH
• indukovaná hypertermie metody   MeSH
• intravenózní infuze metody   MeSH
• isotonické roztoky aplikace a dávkování   MeSH
• lidé MeSH
• nízká teplota MeSH
• terapeutické zahřívání MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

A new β-galactosidase-producing bacterium KGP, isolated from the Bay of Bengal, was identified as Paracoccus marcusii through morphology, biochemistry and 16S rRNA sequencing. This study is the first report on the production of β-galactosidase from P. marcusii. The medium components for the high yield of β-galactosidase were optimised using response surface methodology (RSM). A set of 17 experiments consisting of three independent variables, viz. yeast extract, galactose and MgSO4, was employed. A second-order polynomial equation was used for the analysis of the response, and the optimum β-galactosidase yield was achieved using 12.5 g/L yeast extract, 12.5 g/L galactose and 12.5 mmol/L MgSO4. The predicted quadratic model was inferred to be significant from the F-value, P value and the lack of fit value. Optimisation of the media components resulted in a ninefold increase (560 Miller units) in β-galactosidase production. Furthermore, the hydrolysis and transgalactosylation efficiency of the crude β-galactosidase was assessed and the results showed that the lactose was successfully hydrolysed and transgalactosylated at an optimum temperature of 40 °C and 50 °C, respectively. Considering the overall yield and productivity, P. marcusii can be considered a candidate for the industrial production of β-galactosidase. This study provides an essential basis for the future production and use of the alkali-tolerant β-galactosidase from P. marcusii KGP.

• MeSH
• beta-galaktosidasa metabolismus   MeSH
• bioreaktory MeSH
• fylogeneze MeSH
• galaktosa metabolismus   MeSH
• hydrolýza MeSH
• koncentrace vodíkových iontů MeSH
• laktosa metabolismus   MeSH
• oligosacharidy biosyntéza   MeSH
• Paracoccus klasifikace   genetika   izolace a purifikace   metabolismus   MeSH
• RNA ribozomální 16S genetika   MeSH
• teplota MeSH
• Publikační typ
• časopisecké články MeSH

INTRODUCTION: Macleaya microcarpa (Papaveraceae family) has been of considerable interest in recent years as a prospective source of quaternary benzo[c]phenanthridine alkaloids (QBAs) related to many pharmaceutical beneficial effects. For this purpose, a quantitative, efficient and fast method to isolate the QBAs from the plant material is required. OBJECTIVE: To optimise and compare pressurised liquid extraction (PLE) with Soxhlet extraction and maceration in order to estimate extraction conditions for fast and efficient isolation of QBAs contained in the roots of Macleaya microcarpa. METHODOLOGY: The QBAs were extracted by PLE, Soxhlet extraction and maceration at different conditions (solvent, time, etc.). Reversed phase HPLC with diode-array detector was utilised for their determination and quantification. To optimise the PLE procedure, the variable parameters, including temperature (40-150 °C), sample-to-inert material ratio, extraction time (5-30 min) and number of extraction cycles (1-4), were also tested. RESULTS: Quantitative determination of QBAs resulted in 0.2-2.8 mg/g, 0.3-2.5 mg/g and 0.3-3.1 mg/g for PLE, Soxhlet extraction and maceration. To produce the yields mentioned above, PLE required only up to 30 min compared with 21 h for Soxhlet extraction and 49 days for maceration. CONCLUSION: PLE provided an effective and fast extraction of QBAs from M. microcarpa roots and can be recommended as an alternative isolation method to conventional techniques for QBAs from the plant sources.

• MeSH
• benzofenantridiny chemie   izolace a purifikace   MeSH
• časové faktory MeSH
• chemická frakcionace metody   MeSH
• kořeny rostlin chemie   MeSH
• Papaveraceae chemie   MeSH
• rozpouštědla chemie   MeSH
• senzitivita a specificita MeSH
• teplota MeSH
• tlak MeSH
• vysokoúčinná kapalinová chromatografie metody   normy   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH