共查询到20条相似文献,搜索用时 15 毫秒
1.
Hualing Li Changhong Ren Jinping Shi Xingyi Hang Feilong Zhang Yan Gao Yonghong Wu Langlai Xu Changsheng Chen Chenggang Zhang 《Proteome science》2010,8(1):49
Background
The nematode Caenorhabditis elegans is both sensitive and tolerant to hypoxic stress, particularly when the evolutionarily conserved hypoxia response pathway HIF-1/EGL-9/VHL is involved. Hypoxia-induced changes in the expression of a number of genes have been analyzed using whole genome microarrays in C. elegans, but the changes at the protein level in response to hypoxic stress still remain unclear. 相似文献2.
Jacob D Feala Laurence Coquin Dan Zhou Gabriel G Haddad Giovanni Paternostro Andrew D McCulloch 《BMC systems biology》2009,3(1):91
Background
Cellular hypoxia is a component of many diseases, but mechanisms of global hypoxic adaptation and resistance are not completely understood. Previously, a population of Drosophila flies was experimentally selected over several generations to survive a chronically hypoxic environment. NMR-based metabolomics, combined with flux-balance simulations of genome-scale metabolic networks, can generate specific hypotheses for global reaction fluxes within the cell. We applied these techniques to compare metabolic activity during acute hypoxia in muscle tissue of adapted versus "na?ve" control flies. 相似文献3.
M. Rivera-Ch F. León-Velarde L. Huicho C. Monge-C 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1995,164(8):659-662
The Hb-O2 affinity and the erythropoietic response as a function of time were studied in mice treated with sodium cyanate for up to 2 months. Cyanate increased the Hb-O2 affinity in normoxic mice more than in chronically hypoxic mice. The hemoglobin concentration rose as a function of time both in normoxic and hypoxic conditions but reached higher levels in hypoxia. After 42 days of study (21 days of hypoxia) hemoglobin reached maximum levels and thereafter showed a plateau in both cyanate and control animals. It is concluded that a chronic left-shifted oxygen dissociation curve does not avoid the development of hypoxic polycythemia in mice. Moreover, prolonged cyanate administration potentiates the crythropoietic response to chronic hypoxia. Since polycythemia is an index of tissue hypoxia, the results show that the high hemoglobin affinity did not prevent tissue hypoxia in low PO2 conditions. Results showing beneficial effects of high hemoglobin oxygen affinity induced by cyanate based on acute hypoxic expositions should be cautiously interpreted with regard to their adaptive value in animals chronically exposed to natural or simulated hypoxia.Abbreviations Hb
hemoglobin
- NaOCN
sodium cyanate
- ODC
oxygen dissociation curve
-
P
50
PO2 at which hemoglobin is half saturated with O2 相似文献
4.
Background
To survive and reproduce, animals must be able to modify their motor behavior in response to changes in the environment. We studied a complex behavior of Caenorhabditis elegans, male mating behavior, which provided a model for understanding motor behaviors at the genetic, molecular as well as circuit level. C. elegans male mating behavior consists of a series of six sub-steps: response to contact, backing, turning, vulva location, spicule insertion, and sperm transfer. The male tail contains most of the sensory structures required for mating, in addition to the copulatory structures, and thus to carry out the steps of mating behavior, the male must keep his tail in contact with the hermaphrodite. However, because the hermaphrodite does not play an active role in mating and continues moving, the male must modify his tail posture to maintain contact. We provide a better understanding of the molecular and neuro-muscular pathways that regulate male tail posture during mating. 相似文献5.
6.
Background
Chronic hypoxia is a major component of ischemic diseases such as stroke or myocardial infarction. Drosophila is more tolerant to hypoxia than most mammalian species. It is considered as a useful model organism to identify new mechanisms of hypoxic tolerance. The hypoxic tolerance of flies has previously been reported to be enhanced by low protein diets. This study analyses the mechanisms involved.Results
Feeding adult Drosophila on a yeast diet dramatically reduced their longevities under chronic hypoxic conditions (5% O2). Mean and maximum longevities became close to the values observed for starving flies. The action of dietary yeast was mimicked by a whole casein hydrolysate and by anyone of the 20 natural amino acids that compose proteins. It was mimicked by amino acid intermediates of the urea cycle such as L-citrulline and L-ornithine, and by polyamines (putrescine, spermidine and spermine). α-difluoromethylornithine, a specific inhibitor of ornithine decarboxylase, partially protected hypoxic flies from amino acid toxicity but not from polyamine toxicity. N1-guanyl-1,7 diaminoheptane, a specific inhibitor of eIF5A hypusination, partially relieved the toxicities of both amino acids and polyamines.Conclusion
Dietary amino acids reduced the longevity of chronically hypoxic flies fed on a sucrose diet. Pharmacological evidence suggests that the synthesis of polyamines and the hypusination of eIF5A contributed to the life-shortening effect of dietary amino acids. 相似文献7.
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9.
Kalle T Rytkönen Gillian MC Renshaw Kevin J Ashton Grant Williams-Pritchard Erica H Leder Mikko Nikinmaa 《BMC molecular biology》2010,11(1):27
Background
Elasmobranch fishes are an ancient group of vertebrates which have high potential as model species for research into evolutionary physiology and genomics. However, no comparative studies have established suitable reference genes for quantitative PCR (qPCR) in elasmobranchs for any physiological conditions. Oxygen availability has been a major force shaping the physiological evolution of vertebrates, especially fishes. Here we examined the suitability of 9 reference candidates from various functional categories after a single hypoxic insult or after hypoxia preconditioning in epaulette shark (Hemiscyllium ocellatum). 相似文献10.
Karen A Fagan Brian Morrissey Brian W Fouty Koichi Sato Julie Wright Harral Kenneth G Morris Jr Marloes Hoedt-Miller Shanda Vidmar Ivan F McMurtry David M Rodman 《Respiratory research》2001,2(5):306-8
Background
The importance of nitric oxide (NO) in hypoxic pulmonary hypertension has been demonstrated using nitric oxide synthase (NOS) knockout mice. In that model NO from endothelial NOS (eNOS) plays a central role in modulating pulmonary vascular tone and attenuating hypoxic pulmonary hypertension. However, the normal regulation of NOS expression in mice following hypoxia is uncertain. Because genetically engineered mice are often utilized in studies of NO, we conducted the present study to determine how hypoxia alters NOS expression in wild-type mice. 相似文献11.
12.
Michael D Kennedy Darren ER Warburton Carol A Boliek Ben TA Esch Jessica M Scott Mark J Haykowsky 《Dynamic medicine : DM》2008,7(1):11
Background
It is well known that hypoxic exercise in healthy individuals increases limb blood flow, leg oxygen extraction and limb vascular conductance during knee extension exercise. However, the effect of hypoxia on cardiac output, and total vascular conductance is less clear. Furthermore, the oxygen delivery response to hypoxic exercise in well trained individuals is not well known. Therefore our aim was to determine the cardiac output (Doppler echocardiography), vascular conductance, limb blood flow (Doppler echocardiography) and muscle oxygenation response during hypoxic knee extension in normally active and endurance-trained males.Methods
Ten normally active and nine endurance-trained males (VO2max = 46.1 and 65.5 mL/kg/min, respectively) performed 2 leg knee extension at 25, 50, 75 and 100% of their maximum intensity in both normoxic and hypoxic conditions (FIO2 = 15%; randomized order). Results were analyzed with a 2-way mixed model ANOVA (group × intensity).Results
The main finding was that in normally active individuals hypoxic sub-maximal exercise (25 – 75% of maximum intensity) brought about a 3 fold increase in limb blood flow but decreased stroke volume compared to normoxia. In the trained group there were no significant changes in stroke volume, cardiac output and limb blood flow at sub-maximal intensities (compared to normoxia). During maximal intensity hypoxic exercise limb blood flow increased approximately 300 mL/min compared to maximal intensity normoxic exercise.Conclusion
Cardiorespiratory fitness likely influences the oxygen delivery response to hypoxic exercise both at a systemic and limb level. The increase in limb blood flow during maximal exercise in hypoxia (both active and trained individuals) suggests a hypoxic stimulus that is not present in normoxic conditions.13.
14.
Background
Elucidation of the communal behavior of microbes in mixed species biofilms may have a major impact on understanding infectious diseases and for the therapeutics. Although, the structure and the properties of monospecies biofilms and their role in disease have been extensively studied during the last decade, the interactions within mixed biofilms consisting of bacteria and fungi such as Candida spp. have not been illustrated in depth. Hence, the aim of this study was to evaluate the interspecies interactions of Pseudomonas aeruginosa and six different species of Candida comprising C. albicans, C. glabrata, C. krusei, C. tropicalis, C. parapsilosis, and C. dubliniensis in dual species biofilm development. 相似文献15.
Background
All eukaryotic organisms need to distinguish each of their chromosomes. A few protein complexes have been described that recognise entire, specific chromosomes, for instance dosage compensation complexes and the recently discovered autosome-specific Painting of Fourth (POF) protein in Drosophila. However, no sequences have been found that are chromosome-specific and distributed over the entire length of the respective chromosome. Here, we present a new, unbiased, exhaustive computational method that was used to probe three Drosophila genomes for chromosome-specific sequences. 相似文献16.
Background
Streptomyces coelicolor is a bacterium with a vast repertoire of metabolic functions and complex systems of cellular development. Its genome sequence is rich in genes that encode regulatory proteins to control these processes in response to its changing environment. We wished to apply a recently published bioinformatic method for identifying novel regulatory sequence signals to gain new insights into regulation in S. coelicolor. 相似文献17.
Dwinell M. R.; Janssen P. L.; Pizarro J.; Bisgard G. E. 《Journal of applied physiology》1997,82(1):118-124
Dwinell, M. R., P. L. Janssen, J. Pizarro, and G. E. Bisgard. Effects of carotid body hypocapnia during ventilatory acclimatization to hypoxia. J. Appl.Physiol. 82(1): 118-124, 1997.Hypoxicventilatory sensitivity is increased during ventilatory acclimatizationto hypoxia (VAH) in awake goats, resulting in a time-dependent increasein expired ventilation (E). Theobjectives of this study were to determine whether the increasedcarotid body (CB) hypoxic sensitivity is dependent on the level of CB CO2 and whether the CBCO2 gain is changed during VAH.Studies were carried out in adult goats with CB blood gases controlled by an extracorporeal circuit while systemic (central nervous system) blood gases were regulated independently by the level of inhaled gases. Acute E responsesto CB hypoxia (CB PO2 40 Torr) and CBhypercapnia (CB PCO2 50 and 60 Torr)were measured while systemic normoxia and isocapnia were maintained. CBPO2 was then lowered to 40 Torr for 4 h while the systemic blood gases were kept normoxic and normocapnic.During the 4-h CB hypoxia, E increasedin a time-dependent manner. Thirty minutes after return to normoxia,the ventilatory response to CB hypoxia was significantly increasedcompared with the initial response. The slope of the CBCO2 response was also elevatedafter VAH. An additional group of goats(n = 7) was studied with asimilar protocol, except that CB PCO2was lowered throughout the 4-h hypoxic exposure to prevent reflexhyperventilation. CB PCO2 wasprogressively lowered throughout the 4-h CB hypoxic period to maintainE at the control level. After the 4-hCB hypoxic exposure, the ventilatory response to hypoxia was alsosignificantly elevated. However, the slope of the CBCO2 response was not elevatedafter the 4-h hypoxic exposure. These results suggest that CBsensitivity to both O2 andCO2 is increased after 4 h of CBhypoxia with systemic isocapnia. The increase in CB hypoxic sensitivityis not dependent on the level of CBCO2 maintained during the 4-hhypoxic period. 相似文献
18.
Steele SL Ekker M Perry SF 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2011,181(4):527-538
The rate-limiting enzyme in the biosynthetic pathway of catecholamines is tyrosine hydroxylase (TH), the activity of which
is dependent on molecular oxygen. Zebrafish (Danio rerio) possess two non-allelic TH coding genes, TH1 and TH2. A principal goal of the present study was to determine if the expression of these genes is sensitive to environmental hypoxia.
Additionally, we sought to determine if catecholamine content of larvae was changed by environmental hypoxia, and whether
the hearts of hypoxic larvae were equally responsive to exogenous catecholamine (norepinephrine) exposure. After 2 days of
exposure to hypoxia [5–7 days post-fertilization (dpf); PO2 = 30 Torr] TH2 mRNA expression was significantly lower and dopamine β hydroxylase (DβH) mRNA was significantly higher in whole larvae. Whole body catecholamine levels were unchanged until after 4 days of hypoxic
exposure (5–9 dpf), at which time there was a significant increase in epinephrine and norepinephrine contents. Norepinephrine
content was significantly elevated in the hearts of adult fish after 2 and 4 days of hypoxic exposure, and TH1 mRNA expression was increased in the kidney of both groups. After 2 or 4 days of exposure to hypoxia, larvae displayed significantly
lower heart rates than normoxic fish. However, application of exogenous norepinephrine caused similar increases in heart rate
in both groups. Overall, it is concluded that the mRNA expression of TH1 and TH2 is differentially affected by hypoxia exposure in larvae and adults. Also, catecholamine biosynthesis appears to be activated
by 2 dpf and although whole body catecholamine levels increase during hypoxia (possibly promoting downregulation of cardiac
β-adrenergic receptors), there is no accompanying decrease in the response of the heart to adrenergic stimulation. 相似文献
19.
Bin Jiang Changhong Ren Yuan Li Yiming Lu Weiguang Li Yonghong Wu Yan Gao Peter J. Ratcliffe Huqi Liu Chenggang Zhang 《Journal of biological inorganic chemistry》2011,16(2):267-274
Physical and chemical hypoxia have been widely used in the study of hypoxic injury; however, both of these hypoxia models
have their own limitations. Physical hypoxia is usually difficult to control and maintain. Chemical hypoxia, which is usually
induced by chemical hypoxia-mimicking agents, such as CoCl2, may result in heavy metal toxicity or impose security threats. To develop a more suitable hypoxia model, we focused on sodium
sulfite (Na2SO3) and evaluated its ability to remove dissolved oxygen in aqueous solutions. Our results showed that sodium sulfite successfully
induced hypoxic conditions. The degree of hypoxia and the guarantee period of the sodium sulfite solution could be easily
controlled by the concentration of soluble sodium sulfite. In addition, we used sodium sulfite to create a hypoxia model in
Caenorhabditis elegans. Similar to physical hypoxia, the sodium sulfite solutions induced hypoxia-related death in the worms and led to morphologic
cell defects and C. elegans hypoxia inducible factor 1 stabilization. Taken together, our data show that sodium sulfite is a potential hypoxia inducer
that mimics hypoxic stress in C. elegans. 相似文献
20.
Superoxide dismutase from Helicobacter pylori suppresses the production of pro‐inflammatory cytokines during in vivo infection 下载免费PDF全文