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2. Algae cells with deletion of the segment D210-R226 in γ subunit from chloroplast ATP synthase have lower transmembrane proton gradient and grow slowly
- Creator:
- Ponomarenko, S.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Chlamydomonas, deletion mutant, and proteins
- Language:
- Multiple languages
- Description:
- The γ-subunits of chloroplast ATP synthases are about 30 amino acids longer than the bacterial or mitochondrial homologous proteins. This additional sequence is located in the mean part of the polypeptide chain and includes in green algae and higher plants two cysteines (Cys198 and Cys204 in Chlamydomonas reinhardtii) responsible for thiol regulation. In order to investigate its functional significance, a segment ranging from Asp-D210 to Arg-226 in the γ-subunit of chloroplast ATP synthase from C. reinhardtii was deleted. This deletion mutant called T2 grows photoautotrophically, but slowly than the parental strain. The chloroplast ATP synthase complex with the mutated γ is assembled, membrane bound, and as CF0CF1 displays normal ATPase activity, but photophosphorylation is inhibited by about 20 %. This inhibition is referred to lower light-induced transmembrane proton gradient. Reduction of the proton gradient is apparently caused by a disturbed functional connection between CF1 and CF0 effecting a partially leaky ATP synthase complex.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3. Altered neural and vascular mechanisms in hypertension
- Creator:
- Mária Pintérová, Jaroslav Kuneš, and Jiří Zicha
- Format:
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, bílkoviny, sympatický nervový systém, krevní tlak, proteins, sympathetic nervous system, blood pressure, spontaneously hypertensive rats, alpha- and beta-adrenoceptors, G proteins, L-type voltage-dependent calcium channels, calcium influx, potassium channels, PhoA/Rho-kinase pathway, calcium sensitization, 14, and 612
- Language:
- English
- Description:
- b1_Essential hypertension is a multifactorial disorder which belongs to the main risk factors responsible for renal and cardiovascular complications. This review is focused on the experimental research of neural and vascular mechanisms involved in the high blood pressure control. The attention is paid to the abnormalities in the regulation of sympathetic nervous system activity and adrenoceptor alterations as well as the changes of membrane and intracellular processes in the vascular smooth muscle cells of spontaneously hypertensive rats. These abnormalities lead to increased vascular tone arising from altered regulation of calcium influx through L-VDCC channels, which has a crucial role for excitation-contraction coupling, as well as for so-called “calcium sensitization” mediated by the RhoA/Rho-kinase pathway. Regulation of both pathways is dependent on the complex interplay of various vasodilator and vasoconstrictor stimuli. Two major antagonistic players in th e regulation of blood pressure, i.e. sympathetic nervous system (by stimulation of adrenoceptors coupled to stimulatory and inhibitory G proteins) and nitric oxide (by cGMP signaling pathway), elicit their actions via the control of calcium influx through L-VDCC. However, L-type calcium current can also be regulated by the changes in membrane potential elicited by the activation of potassium channels, the impaired function of which was detected in hypertensive animals. The dominant role of enhanced calcium influx in the pathogenesis of high blood pressure of genetically hypertensive animals is confirmed not only by therapeutic efficacy of calcium antagonists but especially by the absence of hypertension in animals in which L-type calcium current was diminished by pertussis toxin-induced inactivation of inhibitory G proteins., b2_ there is considerable information on th e complex neural and vascular alterations in rats with established hypertension, the detailed description of their appearance during the induction of hypertension is still missing., M. Pintérová, J. Kuneš, J. Zicha., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4. An ideal biological marker of Alzheimer's disease: dream or reality?
- Creator:
- Daniela Řípová and Anna Strunecká
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, Alzheimerova choroba, bílkoviny, recenze, Alzheimer's disease, proteins, reviews, biological peripheral marker, β-amyloid, 14, and 612
- Language:
- English
- Description:
- Senile dementia of Alzheimer´s type (AD) is commonly characterized as a neurodegenerative disorder, which exhibits gradual changes of consciousness, loss of memory, perception and orientation as well as loss of personality and intellect. AD prevalence increases dramatically with age and is the fourth cause of death in Europe and in the USA. Currently, there are no available biological markers, which gives clinicians no other alternative than to rely upon clinical diagnosis by exclusion. There is no assay of objective ante mortem biochemical phenomena that relate to the pathophysiology of this disease. The pathophysiology of AD is connected with alterations in neurotransmission, plaque formation, cytoskeletal abnormalities and disturbances of calcium homeostasis. The search for a test, which is non-invasive, simple, cheap and user-friendly, should be directed at accessible body fluids. Only abnormalities replicated in large series across different laboratories fulfilling the criteria for a biological marker are likely to be of relevance in diagnosing AD. To date, only the combination of cerebrospinal fluid t and Ab42 most closely approximate an ideal biomarker of Alzheimer´s disease. A short review on the role of biological markers in AD on the basis of the literature, contemporary knowledge and our own recent findings are presented., D. Řípová, A. Strunecká., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5. Analysis of some barley chlorophyll mutants and their response to temperature stress
- Creator:
- Gálová, E., Böhmová, B., and Ševčovičová, A.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- fluorescence, heat-shock proteins, Hordeum vulgare, proteins, RNA, and SDS-PAGE
- Language:
- Multiple languages
- Description:
- Six barley chlorophyll (Chl) mutants, viridis, flavoviridis, chlorina, xanhta, lutea, and albina, differed in the contents of Chl (a+b) and carotenoids (Cars). In accordance with their Chl-deficient phenotype, the Chl a and b and Car contents of mutants decreased from viridis to albina, only xantha had the same or even higher concentration of Cars as the wild type plant. The albina mutant completely lacked and xantha had a significantly reduced photosynthetic activity. We found quantitative differences in protein contents between wild type and mutant plants, with the lowest concentration per fresh mass in the albina mutant. Chl fluorescence analysis revealed that heat-treated barley leaves of both the wild type and Chl mutants had a lower photosystem 2 efficiency than the untreated ones. With 35S-methionine labelling and SDS-PAGE we found that six to nine de novo synthetized proteins appeared after heat shock (2 h, 42 °C) in the wild type and Chl mutants. In albina the expression of heat shock proteins (HSPs) was reduced to 50 % of that in the wild type. Hence mainly albina mutants, with a completely destroyed proteosynthetic apparatus of the chloroplasts, are able to synthesize a small set of HSPs. The albina mutant is a very useful tool for the study of different gene expression of chloroplast and nuclear DNA. and E. Gálová, B. Böhmová, A. Ševčovičová.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
6. Biochemical and physiological response to salicylic acid in relation to the systemic acquired resistance
- Creator:
- Chandra, Amaresh and Bhatt, R. K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- carotenoids, chlorophyll, cowpea, net photosynthetic rate, peroxidase, proteins, sugars, and Vigna unguiculata
- Language:
- Multiple languages
- Description:
- In five genotypes of cowpea (Vigna unguiculata), the influence of salicylic acid (SA) on photosynthetic activity and biochemical constituents including peroxidase activity at the genotypic level was determined. After SA treatment the total free sugar content increased in IFC 8401 and IGFRI 450 genotypes, whereas the content of total leaf soluble proteins decreased significantly in IFC 902. The high chlorophyll (Chl) (a + b) content in IFC 902 showed a good correlation with the net photosynthetic rate (PN), as in this genotype a significant increase in PN was found after the SA treatment. and Amaresh Chandra,, R. K. Bhatt.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7. Cd2+ effect on photosynthetic apparatus in Synechococcus elongatus and spinach (Spinacia oleracea L.)
- Creator:
- Nováková, M., Matějová, E., and Sofrová, D.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- cyanobacteria, heavy metals, photochemical activity, photosystem 2, proteins, and ribulose-1,5-bisphosphate carboxylase/oxygenase
- Language:
- Multiple languages
- Description:
- Thylakoid membranes (TM) of the cyanobacterium Synechococcus elongatus were exposed for 30 min to the influence of 0, 10, 100, and 1 000 mM CdCl2 (= Cd0, Cd10, Cd100, and Cd1000). Cd10 and Cd100 caused some increase in activity of photosystem 2, PS2 (H2O → DCPIP), while distinct inhibition was observed with Cd1000. We also observed a similar effect when measuring oxygen evolution (H2O → PBQ + FeCy). Chloroplasts of spinach (Spinacia oleracea L.) were incubated for 30 min with 0, 15, 30, and 60 mM CdCl2 (= Cd0, Cd15, Cd30, and Cd60). All concentrations studied inhibited the PS2 activity, the effect being stronger with increasing concentration of Cd2+. The photosynthetic oxygen evolution activity was also influenced most distinctly by the highest concentration employed, i.e. Cd60. Electrophoretic analysis of the protein composition of cyanobacterium TM showed chief changes in the molecular mass regions of Mr 29 000 and 116 000, while with spinach chloroplasts the most distinct differences were observed in the regions of Mr 15 000 and 50 000. Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO) activity in cyanobacterial spheroplasts still remained on the 40 % level in the case of Cd1000, but it decreased down to approx. 2.5 % in the Cd60 sample of spinach chloroplasts. and M. Nováková, E. Matějová, D. Sofrová.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
8. Chlorophyll-deficient mutant in oak (Quercus petraea L.) displays an accelerated hypersensitive-like cell death and an enhanced resistance to powdery mildew disease
- Creator:
- Repka, V.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll fluorescencce, gene exprpession, hypersensitive reaction, photosynthesis, programmed cell death, proteins, reactive oxygen species, and sugars
- Language:
- Multiple languages
- Description:
- Plants of the discovered chlorophyll-deficient mutant of oak (ML) display enhanced disease resistance to the fungus Erysiphe cichoracearum, causal agent of powdery mildew. Quantitative imaging of chlorophyll (Chl) fluorescence revealed that the net photosynthetic rate (PN) declined progressively in both untreated and invaded ML leaves as well as in inoculated wild-type (WT) leaves. Images of non-photochemical fluorescence quenching (NPQ) in both untreated and infected mutant leaves suggested that the capacity of Calvin cycle had been reduced and that there was a complex metabolic heterogeneity within the ML leaf. The ML mutant accumulates reactive oxygen species, ROS (H2O2) from the oxidative burst followed by spontaneous cell death that mimic the hypersensitive response. Reduction in pathogen sporulation on ML leaves correlated with the accumulation of soluble saccharides and a more rapid induction of defence responses including expression of some defence proteins (β-1,3-glucanase and chitinase). Unlike to WT plants, ML- conferred phenotype activates and/or de-represses multiple defence responses, making them more easily induced by pathogens.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
9. Comparative analysis of ultrastructure, antioxidant enzyme activities, and photosynthetic performance in rice mutant 812HS prone to photooxidation
- Creator:
- Ma, J., Lv, C. F., Zhang, B. B., Wang, F., Shen, W. J., Chen, G. X., Gao, Z. P., and Lv, C. G.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- obecná botanika, bílkoviny, general botany, proteins, malondialdehyde, photophosphorylation, reactive oxygen species, 2, and 581
- Language:
- Multiple languages
- Description:
- Under optimal conditions, most of the light energy is used to drive electron transport. However, when the light energy exceeds the capacity of photosynthesis, the overall photosynthetic efficiency drops down. The present study investigated the effects of high light on rice photooxidation-prone mutant 812HS, characterized by a mutation of leaf photooxidation 1 gene, and its wild type 812S under field conditions. Our results showed no significant difference between 812HS and 812S before exposure to high sunlight. However, during exposure to high light, shoot tips of 812HS turned yellow and their chlorophyll (Chl) content decreased. Transmission electron microscopy showed that photooxidation resulted in significant damage of chloroplast ultrastructure. It was confirmed also by inhibited photophosphorylation and reduced ATP content. The decreased coupling factor of ATP, Ca2+-ATPase and Mg2+-ATPase activities also verified these results. Further, significantly enhanced activities of antioxidative enzymes were observed during photooxidation. Malondialdehyde, hydrogen peroxide, and the superoxide generation rates also increased. Chl a fluorescence analysis found that the performance index and maximum quantum yield of PSII declined on August 4, 20 days after high-light treatment. Net photosynthetic rate also decreased and substomatal CO2 concentration increased in 812HS at the same time. In conclusion, our findings indicated that excessive energy triggered the production of toxic reactive oxygen species and promoted lipid peroxidation in 812HS plants, causing severe damage to cell membranes, degradation of photosynthetic pigments and proteins, and ultimately inhibition of photosynthesis., J. Ma, C. F. Lv, B. B. Zhang, F. Wang, W. J. Shen, G. X. Chen, Z. P. Gao, C. G. Lv., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
10. Composition and characteristic differences in photosynthetic membranes of two ecotypes of reed (Phragmites communis L.) from different habitats
- Creator:
- Zhu, X. Y., Wang, S. M., and Zhang, C. L.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll fluorescence, circular dichroism spectra, ecotypes, electrophoresis, LHC2, natual drought, phytosystems 1 and 2, and proteins
- Language:
- Multiple languages
- Description:
- As compared with the swamp reed (SR) ecotype of Phragmites communis growing in the desert region of northwest China, plants of the dune reed (DR) ecotype from the same region possessed lower chlorophyll (Chl) content in leaves, and less thylakoids and grana stacks in chloroplasts. Tube gel electrophoresis without stain showed that the contents of Chl-protein (Pro) components related to photosystem 2 (PS2) were markedly lower in the DR thylakoid membranes than in the SR thylakoid membranes, while the contents of Chl-Pro components associated with PS1 were almost the same in both types. SDS-PAGE analysis indicated that the content of polypeptides of the light-harvesting Chl a/b complex of PS2 (LHC2) was lower in the DR thylakoids. Besides, the conformation of LHC2 within the DR thylakoid membranes was also altered as indicated by circular dichroism spectra. Hence in the DR, reduced energy harvesting by declining the size of LHC2 might be responsible for the down-regulated PS2 activity. Chl fluorescence parameters. Fv/Fm and quantum efficiency of PS2 (ΦPS2), were lower in the DR leaves than in the SR ones. However, non-photochemical quenching coefficient (qN) was greater in DR than that in SR, implying other energy dissipation way exists in the DR photosynthetic membranes. and X. Y. Zhu, S. M. Wang, C. L. Zhang.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public