Number of results to display per page
Search Results
16602. Variation in carbonic anhydrase activity and its relationship with photosynthesis and dry mass of mustard
- Creator:
- Khan, N.A.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- Carbonic anhydrase (CA) activity and net photosynthetic rate (/’N) in the leaves, and plant dry mass (DM) in twelve cultivars of mustard (Brassica juncea L.) were measured 50, 70 and 90 d after sowing. At different sampling stages CA was strongly associated with PN and DM.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
16603. Variation in parameters affecting risk of human disease due to TBE virus
- Creator:
- Korenberg, E. I. and Kovalevskii, Yu V.
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- tick-borne encephalitis, Ixodes persulcatus, and risk of infection
- Language:
- English
- Description:
- To rank variables affecting risk of human disease due to tick-borne encephalitis (TBE) virus in the Russian Far East, we compared annual changes in ( 1 ) frequency of human contact with vector ticks, (2) prevalence of infection in the tick population and (3) quantity of virus present infected ticks. Sites were sampled uniformly over a 4-year period in a forested region where Ixodes persulcatus serves as the principle vector. The questing density of ticks on vegetation remained relatively constant during the course of this study. The frequency of contacts of the local human population with ticks carrying different doses of the TBE virus was changeable. The rate of TBE infection of humans in the study site corresponded to that of human contacts with highly infected ticks. The density of highly infected ticks represents the principal parameter for determining potential epidemiological significance of a natural TBE focus.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
16604. Variation in the morphology of the wings of the endangered grass-feeding butterfly Coenonympha oedippus (Lepidoptera: Nymphalidae) in response to contrasting habitats
- Creator:
- Jugovic, Jure, Zupan, Sara, Bužan, Elena, and Čelik, Tatjana
- Format:
- print, počítač, and online zdroj
- Type:
- model:article and TEXT
- Subject:
- motýli, babočkovití, křídla (zoologie), adaptace (biologie), butterflies, Nymphalidae, wings (zoology), adaptation (biology), Lepidoptera, Coenonympha oedippus, False Ringlet, classical morphometrics, geometric morphometrics, environmental heterogeneity, 2, and 59
- Language:
- English
- Description:
- At the southern limit of its range the endangered butterfly Coenonympha oedippus inhabits grasslands (wet, dry) that differ significantly in the abundance of its larval hostplants (wet > dry) and mean annual air temperature (wet < dry). We determined the difference in the wing morphology of individuals in the two contrasting habitats to test whether and how traits associated with wing size, shape and eye like spots vary in the sexes and two ecotypes. We show that sexual dimorphism follows the same (wing size and shape, number of eyespots on forewing) or different (relative area of eyespots on hindwings) patterns in the two contrasting habitats. Irrespective of ecotype, females had larger, longer and narrower wings, and more forewing eyespots than males. Sexual dimorphism in the relative area of eyespots on hindwing was female-biased in the wet, but male-biased in the dry ecotype. Ecotype dimorphism in wing size and the relative area of eyespots on the hindwing is best explained by mean annual air temperature and abundance of host-plants. While ecotype dimorphism in wing size did not differ between sexes, neither in direction (wet > dry) or in degree, in the two sexes the relative area of eyespots on hindwing had opposite patterns (males: dry > wet; females: wet > dry) and was more pronounced in males than in females. The differences in wing shape between ecotypes were detected only in the hindwings of males, with more rounded apex in the dry than in the wet ecotype. We discuss the life-history traits, behavioural strategies and selection mechanisms, which largely account for the sex- and ecotype-specific variation in wing morphology., Jure Jugovic, Sara Zupan, Elena Bužan, Tatjana Čelik., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
16605. Variation of photosynthetic characteristics and yield in wild and cultivated species of yams (Dioscorea spp.) from Koraput, India
- Creator:
- Padhan, B. and Panda, D.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, chlorophyll fluorescence, gas exchange, tuber yield, 2, and 581
- Language:
- Multiple languages
- Description:
- Variations in leaf gas-exchange characteristics, PSII activity, leaf pigments, and tuber yield were investigated in seven wild and one cultivated species of Dioscorea from Koraput, India, in order to find out their overall adaptability to the environment. The leaf photosynthetic rate, transpiration, stomatal conductance, water-use efficiency, carboxylation efficiency, and photosynthetic pigments were significantly higher in some wild species compared to the cultivated species. In addition, some wild species showed better photochemical efficiency of PSII, photochemical quenching, and electron transport rate in comparison to cultivated one. Furthermore, leaf dry matter accumulation and tuber yield was also higher in some wild species compared to the cultivated species. Taken together, the wild species, such as D. oppositifolia, D. hamiltonii, and D. pubera, showed the superior photosynthetic efficiency compared to the cultivated D. alata and they could be used for future crop improvement programs., B. Padhan, D. Panda., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
16606. Variation of thorax flight temperature among twenty Australian butterflies (Lepidoptera: Papilionidae, Nymphalidae, Pieridae, Hesperiidae, Lycaenidae)
- Creator:
- Nève, Gabriel and Hall, Casey
- Format:
- print, počítač, and online zdroj
- Type:
- article, články, journal articles, model:article, and TEXT
- Subject:
- Zoologie, otakárkovití, babočkovití, běláskovití, motýli, Papilionidae, Nymphalidae, Pieridae, butterflies, Lepidoptera, Hesperiidae, Lycaenidae, thorax flight temperature, wing loading, infra red thermometer, warming-up rate, physical constraint, allometry, 2, and 59
- Language:
- English
- Description:
- Thermal requirements for flight in butterflies is determined by a combination of external factors, behaviour and physical constraints. Thorax temperature of 152 butterflies was monitored with an infra-red thermometer in controlled laboratory conditions. The temperature at take-off varied from 13.4°C, for a female Heteronympha merope to 46.3°C, for a female Junonia villida. Heteronympha merope, an understorey species, had the lowest recorded take-off temperatures, with females flying at a much lower thorax temperatures than males. Among the tested butterfly species, warming-up rate was positively correlated with take-off temperature and negatively with body mass. Wing loading is a major variable in determining the thorax flight temperature. Butterflies with the highest wing-loadings experienced the highest thorax temperatures at take-off. A notable exception to this rule is Trapezites symmomus, the only Hesperiidae of our data set, which had thorax flight temperatures of 31.5°C and 34.5°C, well within the range of the observed butterflies, despite a wing load ca. five times higher. The high thorax temperature recorded in J. villida is probably linked to its high flight speed. The results highlight the importance of physical constraints such as body size on the thermal requirements for flight across a range of butterfly species., Gabriel Nève, Casey Hall., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
16607. Variations in light energy dissipation in Woodfordia fruticosa leaves during expansion
- Creator:
- Zhang, S.-B. and Zhang, J.-L.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- anthocyanin, leaf expansion, nonphotochemical quenching, gas exchange, photosynthetic electron flow, photorespiration, 2, and 581
- Language:
- Multiple languages
- Description:
- Young leaves of tropical trees frequently appear red in color, with the redness disappearing as the leaves mature. During leaf expansion, plants may employ photoprotective mechanisms to cope with high light intensities; however, the variations in anthocyanin contents, nonphotochemical quenching (NPQ), and photorespiration during leaf expansion are poorly understood. Here, we investigated pigment contents, gas exchange, and chlorophyll (Chl) fluorescence in Woodfordia fruticosa leaves during their expansion. Young red leaves had significantly lower Chl content than that of expanding or mature leaves, but they accumulated significantly higher anthocyanins and dissipated more excited light energy through NPQ. As the leaves matured, net photosynthetic rate, total electron flow through PSII, and electron flow for ribulose-1,5-bisphosphate oxygenation gradually increased. Our results provided evidence that photorespiration is of fundamental importance in regulating the photosynthetic electron flow and CO2 assimilation during leaf expansion., S.-B. Zhang, J.-L. Zhang., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
16608. Variations of leaf morphology, photosynthetic traits and water-use efficiency in Western-Mediterranean tomato landraces
- Creator:
- Fullana-Pericàs, M., Conesa, M. À., Soler, S., Ribas-Carbó, M., Granell, A., and Galmés, J.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- asimilace uhlíku, izotopové složení uhlíku, difúzní omezen, morfologie listu, efektivita využívání vody, rajče, carbon assimilation, carbon isotope composition, diffusive limitations, mesophyll conductance, leaf morphology, water-use efficiency, tomato, 2, and 581
- Language:
- Multiple languages
- Description:
- Modern tomato (Solanum lycopersicum L.) breeding has mainly focused on increasing productivity under unlimited watering. In contrast, some Mediterranean accessions have been traditionally cultivated under water shortage and selected on the basis of their water-use efficiency (WUE). Ramellet and Penjar landraces were planted with other traditional, old and modern inbreeds, under full irrigation. In order to found differences between the tomato accessions, gas-exchange and leaf morphology measurements were performed. Despite high variability, Ramellet and Penjar presented clear differences compared to modern cultivars, mostly related to leaf morphology and photosynthetic traits, while no differences were found in WUE. Results highlighted that better leaf CO2 conductance might be a main factor determining the improvement of net CO2 assimilation and WUE., M. Fullana-Pericàs, M. À. Conesa, S. Soler, M. Ribas-Carbó, A. Granell, J. Galmés., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
16609. Vascular metabolic dysfunction and lipotoxicity
- Creator:
- Mattern, H. M. and Hardin, C. D.
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie, cévní, apoptóza, physiology, smooth muscles, apoptosis, hladké svaly cév, palmitát, oleát, reaktivní formy kyslíku, vascular smooth muscle, palmitate, oleate, reactive oxygen species, 14, and 612
- Language:
- English
- Description:
- The purpose of this study was to determine the role of lipotoxicity in vascular smooth muscle (VSM). C1-BODIPY 500/510 C12 used to assess the ability of VSM A7r5 cells to transport long-chain fatty acids showed that lipid transport did not appear to limit metabolism. Thin layer chromatography revealed that storage of transported fatty acid occurred primarily as mono- and diglycerides and fatty acids but not as triglycerides. We used lipid-induced apoptosis as a measure of lipotoxicity and found that 1.5 mM palmitate (6.8:1) bound to albumin resulted in a 15-fold increase in the number of apoptotic cells compared to the control at 24 hours. This apoptosis did not seem to be due to an increase in reactive oxygen species (ROS) since VSM cells incubated in palmitate showed less ROS production than cells incubated in albumin only. Similar exposure to oleate did not significantly increase the number of apoptotic cells compared to the control. Oleate actually significantly attenuated the apoptosis induced by palmitate, suggesting that unsaturated fatty acids have a protective effect on cells undergoing palmitate-induced apoptosis. These results suggest that vascular smooth muscle is vulnerable to lipotoxicity and that this lipotoxicity may play a role in the development of atherosclerosis., H. M. Mattern, C. D. Hardin., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
16610. Vascular stenosis asymmetry influences considerably pressure gradient and flow volume
- Creator:
- Novakova, L., Kolinsky, J., Adamec, J., Kudlicka, J., and Jan Malík
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, ateroskleróza, atherosclerosis, stenosis, dialysis access, pressure gradient, 14, and 612
- Language:
- English
- Description:
- Vascular stenosis is often described only by its percentage in both clinical and scientific praxis. Previous studies gave inconclusive results regarding the effect of stenosis eccentricity on its hemodynamic effect. The aim of this experimental study was to investigate and quantify the effect of stenosis severity and eccentricity on the pressure drop. A combination of pressure and flow measurements by Par ticle Imaging Velocimetry (PIV) method was used. Models of the same stenosis significance but with different levels of eccentricity were studied in vitro by PIV. This study has shown that stenosis asymmetry is associated with more profound pressure drop an d flow volume decrease. On the contrary, pressure drop and flow volume decrease were not further significantly influenced by the level of asymmetry. Hemodynamic changes associated with stenosis eccentricity must be taken into account in both clinical and s cientific studies., L. Novakova, J. Kolinsky, J. Adamec, J. Kudlicka, J. Malik., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public