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991.
Naoki Mizusawa Shinya Sakata Isamu Sakurai Naoki Sato Hajime Wada 《Archives of microbiology》2009,191(7):595-601
The effects of digalactosyldiacylglycerol (DGDG) deficiency on photosynthesis at high temperatures were examined using a dgdA mutant of Synechocystis sp. PCC 6803 incapable of DGDG biosynthesis. The dgdA mutant cells showed significant growth retardation when the temperature was increased from 30 to 38°C, although wild-type
cells grew normally. The degree of growth retardation was enhanced by increasing light intensity. In addition, dgdA mutant cells showed increased sensitivity to the photoinhibition of photosynthesis when illuminated at 38°C. Analysis of
photosynthesis in intact cells suggested that the inhibition of repair processes and accelerated photodamage resulted in growth
retardation in dgdA mutant cells at high temperatures. 相似文献
992.
993.
Alexis Jourdain Mariusz Karbowski Yves Mattenberger Sébastien Herzig Pascaline Clerc Ines Raschke Carsten Merkwirth Sarah Ehses Frank Krause David C Chan Christiane Alexander Christoph Bauer Richard Youle Thomas Langer Jean‐Claude Martinou 《The EMBO journal》2009,28(11):1589-1600
Mitochondria are dynamic organelles, the morphology of which results from an equilibrium between two opposing processes, fusion and fission. Mitochondrial fusion relies on dynamin‐related GTPases, the mitofusins (MFN1 and 2) in the outer mitochondrial membrane and OPA1 (optic atrophy 1) in the inner mitochondrial membrane. Apart from a role in the maintenance of mitochondrial DNA, little is known about the physiological role of mitochondrial fusion. Here we report that mitochondria hyperfuse and form a highly interconnected network in cells exposed to selective stresses. This process precedes mitochondrial fission when it is triggered by apoptotic stimuli such as UV irradiation or actinomycin D. Stress‐induced mitochondrial hyperfusion (SIMH) is independent of MFN2, BAX/BAK, and prohibitins, but requires L‐OPA1, MFN1, and the mitochondrial inner membrane protein SLP‐2. In the absence of SLP‐2, L‐OPA1 is lost and SIMH is prevented. SIMH is accompanied by increased mitochondrial ATP production and represents a novel adaptive pro‐survival response against stress. 相似文献
994.
995.
This paper analyzes two mechanisms applied on the human body in order to study the thermoregulatory system according to heat generation and heat loss. Two approaches are presented. The first approach is based on plethysmography, where an armband is placed on the forearm in order to modulate the blood flow. The second approach uses a cold stimulation. The visualization is achieved using infrared imaging devices. The resulting images reveal a temperature balance between the stimulated and the non-stimulated hands. The thermal behavior and typical thermographic recordings on each subject are discussed and analyzed in response to different stimulations. 相似文献
996.
Differential effects of nitrogen and phosphorus enrichment on growth of dwarf Avicennia marina mangroves 总被引:1,自引:0,他引:1
The effects of N and P enrichment were investigated on growth and physiological responses of dwarf Avicennia marina mangroves in a hypersaline (58 ± 8 psu) field site in Richards Bay, South Africa. It was hypothesized that at high salinities mangroves allocate more resources to roots than shoots, and that nutrient enrichment with N and P will shift resource allocation to shoots and enhance growth and productivity. In unvegetated areas of the dwarf zone, 1-year-old A. marina seedlings were planted in pots and enriched bimonthly with N, P, N + P, or remained unfertilized (control-C), and growth and morphology of plants were monitored for 2 years. Enrichment with N and N + P shifted resource allocation to shoots from 38% to 55%, and increased dry biomass accumulation by over 500%, compared to the control treatment. In the N and N + P treatments, plant height, number of leaves, leaf chlorophyll content and photosynthesis increased by over 50%, 330%, 30% and 30%, respectively, compared to the C and P treatments. Enrichment with N and N + P increased N concentrations in roots by over 60% (from 1.0 ± 0.1% to 1.6 ± 0.2% of dry mass) and in shoots by over 100% (from 1.3 ± 0.1% to 2.7 ± 02% of dry mass). Plants enriched with P alone were similar to those of the control. This study has demonstrated that dwarf A. marina in Richards Bay is N limited, and that N enrichment shifts resource allocation from roots to shoots and increases growth and productivity. 相似文献
997.
内质网应激与心肌肥大 总被引:2,自引:0,他引:2
肌浆网是调控心肌细胞钙稳态、蛋白质合成和细胞凋亡的重要亚细胞器。内质网应激是指内质网理化环境改变和过负荷等因素导致未折叠/误折叠蛋白在内质网聚集和钙稳态失衡等内质网功能紊乱状态。适度的内质网应激有利于心肌细胞代偿,持续而严重的内质网应激则触发内质网应激相关细胞凋亡,造成肥大心肌由代偿转向衰竭,是影响心肌肥大发生、发展的重要因素。本文综述了内质网应激反应在心肌肥大发生、发展中的作用。 相似文献
998.
Cristie Grazziotin Noschang Rachel Krolow Leticia Ferreira Pettenuzzo Mônica Colpini Ávila Andrelisa Fachin Danusa Arcego Eduardo von Pozzer Toigo Leonardo Machado Crema Luísa Amália Diehl Deusa Vendite Carla Dalmaz 《Neurochemical research》2009,34(9):1568-1574
We studied the effect of chronic caffeine on parameters related to oxidative stress in different brain regions of stressed
and non-stressed rats. Wistar rats were divided into three groups: control (receiving water), caffeine 0.3 g/L and caffeine
1.0 g/L (in the drinking water). These groups were subdivided into non-stressed and stressed (repeated restraint stress during
40 days). Lipid peroxide levels and the total radical-trapping potential were assessed, as well as antioxidant enzyme activities
superoxide dismutase, gluthatione peroxidase, and catalase in hippocampus, striatum and cerebral cortex. Results showed interactions
between stress and caffeine, especially in the cerebral cortex, since caffeine increased the activity of some antioxidant
enzymes, but not in stressed animals. We concluded that chronic administration of caffeine led, in some cases, to increased
activity of antioxidant enzymes. However, these effects were not observed in the stressed animals. 相似文献
999.
Charlene Cavalheiro de Menezes Aracélli Gnatta Dorneles Rita Leal Sperotto Marta Medeiros Frescura Duarte Maria Rosa Chitolina Schetinger Vania Lúcia Loro 《Neurochemical research》2009,34(7):1255-1260
This study aimed to determine whether patients with aseptic and bacterial meningitis presented alterations in oxidative stress
parameters of cerebrospinal fluid (CSF). A total of 30 patients were used in the research. The CSF oxidative stress status
has been evaluated through many parameters, such as lipid peroxidation through thiobarbituric acid reactive substances (TBARS)
and antioxidant defense systems such as superoxide dismutase (SOD), glutathione S-transferase (GST), reduced glutathione (GSH) and ascorbic acid. TBARS levels, SOD and GST activity increase in aseptic meningitis
and in bacterial meningitis. The ascorbic acid concentration increased significantly in patients with both meningitis types.
The reduced glutathione levels were reduced in CSF of patients with aseptic and bacterial meningitis. In present study we
may conclude that oxidative stress contributes at least in part to the severe neurological dysfunction found in meningitis. 相似文献
1000.
Marcos Roberto de Oliveira Max William Soares Oliveira Guilherme Antônio Behr Matheus Augusto de Bittencourt Pasquali José Cláudio Fonseca Moreira 《Neurochemical research》2009,34(8):1410-1416
Vitamin A, beyond its biological role, is an alternative choice in treating some life threatening pathologies, for instance
leukemia and immunodeficiency. On the other hand, vitamin A therapy at moderate to high doses has caused concern among public
health researchers due to the toxicological aspect resulting from such habit. It has been described hepatotoxicity, cognitive
disturbances and increased mortality rates among subjects ingesting increased levels of vitamin A daily. Then, based on the
previously reported data, we investigated here receptor for advanced glycation endproducts (RAGE) immunocontent and oxidative
damage levels in cerebral cortex of vitamin A-treated rats at clinical doses (1,000–9,000 IU/kg day−1). RAGE immunocontent, as well as oxidative damage levels, were observed increased in cerebral cortex of vitamin A-treated
rats. Whether increased RAGE levels exert negative effects during vitamin A supplementation it remains to be investigated,
but it is very likely that deleterious consequences may arise from such alteration. 相似文献