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1722. Changes in effects of ozone exposure on growth, photosynthesis, and respiration of Ginkgo biloba in Shenyang urban area
- Creator:
- He, X.-Y., Fu, S.-L., Chen, W., Zhao, T.-H., Xu, S., and Tuba, Z.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- carboxylation efficiency, chlorophyll, dark respiration, gas exchange, intercellular CO2 concentration, leaf area index, non-stomatal limitations, photorespiration, stomatal conductance, and transpiration rate
- Language:
- Multiple languages
- Description:
- An open-top chamber experiment was carried out from April through October 2006 to examine the effects of elevated (80 nmol mol-1) atmospheric O3 on Ginkgo biloba (4-years-old) in urban area. The air with ambient O3 (AA, ≈ 45 nmol mol-1) was used as control. The leaf mass and size, leaf area index, net photosynthetic rate (PN), apparent quantum yield, transpiration rate, and stomatal conductance were decreased by elevated O3 (EO) exposure. Visible foliar injury, which is light-brown flecks, was observed in the EO OTCs after 90 d of exposure. Carboxylation efficiency (ΦCO2) and photorespiration and dark respiration rates were enhanced by EO exposure in the first half of the season, but all of them turned to be lower than those of the AA control at the end of experiment. Stomata limitation of photosynthesis was significantly higher than control in the whole season (p<0.05). Chlorophyll (Chl) content was lower in EO variant than in the control and the difference became more and more apparent through the season. Hence the decrease in PN of G. biloba exposed to EO was the result of both stomatal and non-stomatal limitations. In the early season, the inhibition of photosynthesis was mainly caused by the stomatal limitation, and the earliest response was photoprotective down-regulation of photosynthesis but not photodamage. However, at the end of the season, the non-stomatal limiting factors such as decrease in Chl content, decrease in ΦCO2, and anti-oxidative enzyme activity became more important. and X.-Y. He ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1723. Changes in electron transport, superoxide dismutase and ascorbate peroxidase isoenzymes in chloroplasts and mitochondria of cucumber leaves as influenced by chilling
- Creator:
- Hu, W. H., Song, X. S., Shi, K., Xia, X. J., Zhou, Y. H., and Yu, J. Q.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- ascorbate peroxidase, Cucumis sativus, net photosynthetic rate, photosynthetic electron transport, quantum efficiency, reactive oxidative metabolism, respiratory electron transport, respiration pathways, and superoxide dismutase
- Language:
- Multiple languages
- Description:
- In order to clarify the relationship between chill-induced disturbance in photosynthetic, respiratory electron transport and the metabolism of reactive oxygen species (ROS), leaf gas exchange, chlorophyll fluorescence quenching, respiration, and activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX) were investigated in chloroplasts and mitochondria of cucumber (Cucumis sativus) leaves subjected to a chill (8 °C) for 4 d. Chilling decreased net photosynthetic rate (PN) and quantum efficiency of photosystem 2 (ΦPS2), but increased the ratio of ΦPS2 to the quantum efficiency of CO2 fixation (ΦCO2) and non-photochemical quenching (NPQ) in cucumber leaves. While chilling inhibited the activity of cytochrome respiration pathway, it induced an increase of alternative respiration pathway activity and the reduction level of Q-pool. Chilling also significantly increased O2* production rate, H2O2 content, and SOD and APX activities in chloroplasts and mitochondria. There was a more significant increase in SOD and APX activities in chloroplasts than in mitochondria with the increase of membrane-bound Fe-SOD and tAPX in chloroplasts being more significant than other isoenzymes. Taken together, chilling inhibited PN and cytochrome respiratory pathway but enhanced the photosynthetic electron flux to O2 and over-reduction of respiratory electron transport chain, resulting in ROS accumulation in cucumber leaves. Meanwhile, chilling resulted in an enhancement of the protective mechanisms such as thermal dissipation, alternative respiratory pathway, and ROS-scavenging mechanisms (SODs and APXs) in chloroplasts and mitochondria. and W. H. Hu ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1724. Changes in Extracellular Space Volume and Geometry Induced by Cortical Spreading Depression in Immature and Adult Rats
- Creator:
- Tomáš Mazel, Richter, F., Lýdia Vargová, and Eva Syková
- Format:
- print, bez média, and svazek
- Type:
- article, studie, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, Cell swelling, Cortex, Diffusion, Spreading depression, Extracellular space, 14, and 612
- Language:
- English
- Description:
- Changes in extracellular space (ECS) diffusion parameters, DC potentials and extracellular potassium concentration were studied during single and repeated cortical spreading depressions (SD) in 13-15 (P13-15), 21 (P21) and 90-day-old (adult) Wistar rats. The real-time iontophoretic method using tetramethylammonium (TMA+)-selective microelectrodes was employed to measure three ECS parameters in the somatosensory cortex: the ECS volume fraction α (α = ECS volume/total tissue volume), ECS tortuosity λ (increase in diffusion path length) and the nonspecific TMA+ uptake k’. SD was elicited by needle prick. SD was significantly longer at P13-15 than at P21 and in adults. During SD, α in all age groups decreased from 0.21-0.23 to 0.05-0.09; λ increased from 1.55-1.65 to 1.95-2.07. Ten minutes after SD, α (in adults) and λ (all age groups) increased compared to controls. This increase persisted even 1 hour after SD. When SD was repeated at 1 hour intervals, both α and λ showed a gradual cumulative increase with SD repetition. Our study also shows that cortical SD is, as early as P13, accompanied by severe ECS shrinkage and increased diffusion path length (tortuosity) with values similar to adults, followed by a long-lasting increase in ECS volume and tortuosity when compared to pre-SD values., T. Mazel, F. Richter, L. Vargová, E. Syková., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1725. Changes in FGF21 serum concentrations and liver mRNA expression in an experimental model of complete lipodystrophy and insulin-resistant diabetes
- Creator:
- Špolcová, A., Holubová, M., Mikulášková, B., Nagelová, V., Štofková, A., Zdeňka Lacinová, Jana Jurčovičová, Martin Haluzík, Lenka Maletínská, and Železná, B.
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, inzulinová rezistence, játra, insulin resistance, liver, FGF21, A-ZIP mice, lipodystrophy, fatty liver, GLUT-1, 14, and 612
- Language:
- English
- Description:
- Patients with obesity and type 2 diabetes often display high levels of the anti-diabetic factor fibroblast growth factor-21 (FGF21), suggesting that the overproduction of FGF21 may result from increased adiposity in an attempt by white adipose tissue (WAT) to counteract insulin resistance. However, the production of FGF21 diabetes in the absence of WAT has not been examined. In this study, we investigated the effects of lipodystrophy in A-ZIP F-1 mice on FGF21 production in relation to diabetes. A-ZIP F-1 mice displayed high FGF21 plasma levels resulting from enhanced FGF21 mRNA expression in the liver. Concomitant enhancement of FGF21 receptor (FGFR1) and glucose transporter 1 (GLUT-1) mRNA expression was observed in the muscles of A-ZIP F-1 mice. Furthermore, the activation of hypothalamic NPY and AgRP mRNA expression positively correlated with plasma levels of FGF21 but not active ghrelin. Our study demonstrates that an increased FGF21 plasma level in lipodystrophic A-ZIP F-1 mice results mainly from up-regulated liver production but does not suffice to overcome the lipodystrophy-induced severe type 2-diabetes and insulin resistance in the liver linked to the augmented liver fat deposition., A. Špolcová, M. Holubová, B. Mikulášková, V. Nagelová, A. Štofková, Z. Lacinová, J. Jurčovičová, M. Haluzík, L. Maletínská, B. Železná., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1726. Changes in leaf photosynthesis of transgenic rice with silenced OsBP-73 gene
- Creator:
- Chen, Y. and Xu, D.-Q.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- carboxylation efficiency, intercellular CO2 concentration, net photosynthetic rate, photochemical efficiency, Oryza, ribulose-1,5-bisphosphate (RuBP), ribulose-1,5-bisphosphate carboxylase, oxygenase (RuBPCO), RNA interference, RuBP regeneration limitation, and stomatal conductance
- Language:
- Multiple languages
- Description:
- In comparison with its wild type (WT), the transgenic (TG) rice with silenced OsBP-73 gene had significantly lower plant height, grain number per panicle, and leaf net photosynthetic rate (PN). Also, the TG rice showed significantly lower chlorophyll (Chl), ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO), RuBPCO activase, and RuBP contents, photosystem 2 (PS2) photochemical efficiency (Fv/Fm and ΔF/Fm'), apparent quantum yield of carbon assimilation (Φc), carboxylation efficiency (CE), photosynthetic electron transport and photophosphorylation rates as well as sucrose phosphate synthase activity, but higher intercellular CO2 concentration, sucrose, fructose, and glycerate 3-phosphate contents, and non-photochemical quenching of Chl fluorescence (NPQ). Thus the decreased PN in the TG rice leaves is related to both RuBP carboxylation and RuBP regeneration limitations, and the latter is a predominant limitation to photosynthesis. and Y. Chen, D.-Q. Xu.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1727. Changes in lung surfactant proteins in rats with lipololysaccharide-induced fever
- Creator:
- Kolomaznik, M., Zila, I., Kopincova, J., Daniela Mokrá, and Andrea Čalkovská
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, horečka, bronchoalveolární laváž, fever, bronchoalveolar lavage, surfactant specific proteins, lipopolysaccharide, rat model, lung homogenate, 14, and 612
- Language:
- English
- Description:
- The study was designed to prove the hypothesis that lipopolysaccharide (LPS)-induced fever elicits the changes in surfactant specific proteins, potentially related to thermal tachypnea. In adult rats fever was induced by intraperitoneal administration of LPS at a dose 100 μg/kg of body weight; control group received saline. Respiratory parameters, arterial blood gases and pH and colonic body temperature (BT) were recorded. Five hours later, surfactant proteins (SP) A, B, C and D were evaluated in bronchoalveolar lavage fluid (BALF) and lung tissue (LT). LPS evoked monophasic thermic response (at 300 min 38.7±0.2 vs. 36.4±0.3 °C, P<0.05) and an increase in minute ventilation due to changes in breathing rate and tidal volume. LPS-instilled animals had higher levels of SP-A and SP-D in LT (P<0.05 and 0.01), and higher SP-D in BALF (P<0.01) than controls. SP-B increased in LT and SP-C in BALF of animals with LPS (both P0.05 vs. controls). The changes in all surfactant specific proteins are present in LPS-induced fever. Alterations of proteins related to local immune mechanisms (SP-A, SP-D) are probably a part of general inflammatory response to pyrogen. Changes in proteins related to surface activity (SP-B and SP-C) might reflect the effort of the body to stabilize the lungs in thermal challenge., M. Kolomaznik, I. Zila, J. Kopincova, D. Mokra, A. Calkovska., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1728. Changes in morphology, anatomy, and photosynthetic capacity of needles of Japanese larch (Larix kaempferi) seedlings grown in high CO2 concentrations
- Creator:
- Eguchi, N., Fukatsu, E., Funada, R., Tobita, H., Kitao, M., Maruyama, Y., and Koike, T.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- carboxylation efficiency, cell number, intercellular CO2 concentration, mesophyll surface area, needle thickness and width, net photosynthetic rate, nitrogen content, specific leaf area, and starch
- Language:
- Multiple languages
- Description:
- Photosynthetic traits of two-year-old Japanese larch seedlings (Larix kaempferi Carr.) grown at elevated CO2 concentrations were studied in relation to structural changes in the needles. Seedlings were grown at two CO2 concentrations, 360 (AC) and 720 (EC) μmol mol-1 at high and low nutrient supply rates, high N (HN) and low N (LN). The photosynthetic capacity fell significantly in EC+LN, but increased significantly in EC+HN. Since the mesophyll surface area exposed to intercellular space per unit leaf area (Ames/A) is correlated with the photosynthetic rate, we measured Ames/A for larch needles growing in EC. Changes of Ames/A in both EC+HN and EC+LN were very similar to the changes in photosynthetic capacity. This suggests that the changes of Ames/A in EC probably caused the changes in the photosynthetic capacity. The changes of Ames/A in EC were attributed to changes in the mesophyll cell size and mesophyll cell number. The photosynthetic capacity in EC can be explained by taking morphological and structural adaptations into account as well as biochemical factors. and N. Eguchi ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1729. Changes in net photosynthetic rate and chlorophyll fluorescence in potato leaves induced by water stress
- Creator:
- Basu, P. S., Sharma, Ashoo, and Sukumaran, N. P.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- drought, electron transport, feedback inhibition, photochemical quenching, osmotic potential, quantum yield, Solanum ruberosum, and water potential
- Language:
- Multiple languages
- Description:
- Net rates of photosynthesis (PN) saturated by irradiance of >500 μmol m-2 s-1 (PAR) significantly decreased in water-stressed potato (Solanum tuberosum L. cv. Kufri Sindhuri) plants. The quantum yield of photochemical energy conversion (Fv/Fm), relative electron transport rate (ETR), and photochemical quenching (Qp) exhibited a parallel decline at high irradiance. A slight decrease in relative water content (RWC) was accompanied by a drastic decline in leaf water potential (Ψw) from -0.2 to -1.0 MPa. Dehydrated leaves showed an increase in the amount of total soluble sugars per unit leaf area which inhibited the photosynthesis in a feedback manner. After rewatering, PN and Fv/Fm were restored to the values of control plants within 24 h, and the restoration was accompanied by a proportionate lowering of content of total soluble sugars in the leaves. and P. S. Basu, Ashoo Sharma, N. P. Sukumaran.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1730. Changes in neuronal activity of the inferior colliculus in rat after temporal inactivation of the auditory cortex
- Creator:
- Jiří Popelář, Nwabueze-Ogbo, F. C., and Josef Syka
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, neurony, neurons, inferior colliculus, auditory cortex, functional ablation, descending pathway, 14, and 612
- Language:
- English
- Description:
- The role of cortico-tectal pathways in auditory signal processing was studied in anesthetized rats by comparing the extracellular single unit activity in the inferior colliculus (IC) before and after functional ablation of the auditory cortex (AC) by tetrodotoxin (TTX). The responses of several IC neurons to sound stimuli were simultaneously recorded with a 16-channel electrode probe introduced into the IC. Click-evoked middle latency responses (MLR) recorded from the AC were suppressed for several hours after TTX injection. During AC inactivation the firing rate of IC neurons increased (40 % of neurons), decreased (44 %) or did not change (16 %) in comparison with control conditions. In several IC neurons, TTX injection resulted in alterations in the shape of the rate-level functions. Response thresholds, tuning properties and the type of discharge pattern of IC neurons were not altered during AC inactivation. However, in one-third of the neurons, the initial part of the response was less altered than the later, sustained part. In two-thirds of neuronal pairs, functional decortication resulted in a change in the cross-correlation coefficient. The results reveal the complex changes that appear in IC neuronal activity after functional ablation of the ipsilateral auditory cortex., J. Popelář, F. C. Nwabueze-Ogbo, J. Syka., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public