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81.
Juha Heijari Minna Kivimäenpää Helinä Hartikainen Riitta Julkunen-Tiitto Anu Wulff 《Plant and Soil》2006,282(1-2):27-39
In greenhouse experiments, selenium (Se) has been shown to defend plants against detrimental effects of heavy UV-B radiation
stress. The aim of this study was to investigate whether this positive effect can be found in open-field conditions with enhancement
of UV-B radiation. In the experiment, conducted with strawberry (Fragaria×ananassa, cultivars “Jonsok” and “Polka”) over two growing seasons, plants were exposed to UV-B radiation (including UV-A) and cultivated
without Se or supplied with Se added at two levels (0.1 and 1.0 mg kg−1). The plants were monitored for growth, flavonoids, chlorophyll fluorescence, net photosynthesis as well as tissue and cell
structure. Photosystem II was observed to be sensitive to UV-B stress under field conditions. In the leaves, a decrease in
Fv/Fm was seen at the end of the growing season, implying a cumulative effect of UV-B stress. Several parameters, especially cell
and tissue structures, were affected by UV-B and UV-A treatments, which proves the need for UV-A control in outdoor UV-B supplementation
studies. Addition of Se did not ameliorate the harmful effects of UV-B but the lower Se-increment level increased leaf growth.
The effects of UV-B and Se differed during the two experimental years, indicating the need to repeat experiments during several
growing seasons. 相似文献
82.
Selective photostimulation of genetically chARGed neurons. 总被引:2,自引:0,他引:2
To permit direct functional analyses of neural circuits, we have developed a method for stimulating groups of genetically designated neurons optically. Coexpression of the Drosophila photoreceptor genes encoding arrestin-2, rhodopsin (formed by liganding opsin with retinal), and the alpha subunit of the cognate heterotrimeric G protein--an explosive combination we term "chARGe"--sensitizes generalist vertebrate neurons to light. Illumination of a mixed population of neurons elicits action potentials selectively and cell-autonomously in its genetically chARGed members. In contrast to bath-applied photostimulants or caged neurotransmitters, which act indiscriminately throughout the illuminated volume, chARGe localizes the responsiveness to light. Distributed activity may thus be fed directly into a circumscribed population of neurons in intact tissue, irrespective of the spatial arrangement of its elements. 相似文献
83.
Hybrid cells are readily formed by fusing clonal Chinese hamster cells to fresh, noncultured, adult mouse spleen cells followed by isolation in selective medium. The vast majority of such hybrids retain Chinese hamster chromosomes and isozymes while segregating mouse chromosomes and isozymes. The growth, plating efficiency, ease of karyology, and rapid segregation of mouse markers allows linkage tests in primary clones. Analysis of 13 isozymes showed 12 to be asyntenic and on epair (PGD-PGM2) to be syntenic This system will allow extensive somatic cell hybrid gene mapping in the mouse and permit a comparison of human and mouse linkage relationships. 相似文献
84.
Jeong Y Xie Y Lee W Bookout AL Girard L Raso G Behrens C Wistuba II Gadzar AF Minna JD Mangelsdorf DJ 《Molecular endocrinology (Baltimore, Md.)》2012,26(8):1443-1454
Lung cancer is the leading cause of cancer-related death. Despite a number of studies that have provided prognostic biomarkers for lung cancer, a paucity of reliable markers and therapeutic targets exist to diagnose and treat this aggressive disease. In this study we investigated the potential of nuclear receptors (NRs), many of which are well-established drug targets, as therapeutic markers in lung cancer. Using quantitative real-time PCR, we analyzed the expression of the 48 members of the NR superfamily in a human panel of 55 normal and lung cancer cell lines. Unsupervised cluster analysis of the NR expression profile segregated normal from tumor cell lines and grouped lung cancers according to type (i.e. small vs. non-small cell lung cancers). Moreover, we found that the NR signature was 79% accurate in diagnosing lung cancer incidence in smokers (n = 129). Finally, the evaluation of a subset of NRs (androgen receptor, estrogen receptor, vitamin D receptor, and peroxisome proliferator-activated receptor-γ) demonstrated the therapeutic potential of using NR expression to predict ligand-dependent growth responses in individual lung cancer cells. Preclinical evaluation of one of these receptors (peroxisome proliferator activated receptor-γ) in mouse xenografts confirmed that ligand-dependent inhibitory growth responses in lung cancer can be predicted based on a tumor's receptor expression status. Taken together, this study establishes NRs as theragnostic markers for predicting lung cancer incidence and further strengthens their potential as therapeutic targets for individualized treatment. 相似文献
85.
86.
T Kaambre V Chekulayev I Shevchuk M Karu-Varikmaa N Timohhina K Tepp J Bogovskaja R Kütner V Valvere V Saks 《Journal of bioenergetics and biomembranes》2012,44(5):539-558
The aim of this study was to analyze quantitatively cellular respiration in intraoperational tissue samples taken from human breast cancer (BC) patients. We used oxygraphy and the permeabilized cell techniques in combination with Metabolic Control Analysis (MCA) to measure a corresponding flux control coefficient (FCC). The activity of all components of ATP synthasome, and respiratory chain complexes was found to be significantly increased in human BC cells in situ as compared to the adjacent control tissue. FCC(s) were determined upon direct activation of respiration with exogenously-added ADP and by titrating the complexes with their specific inhibitors to stepwise decrease their activity. MCA showed very high sensitivity of all complexes and carriers studied in human BC cells to inhibition as compared to mitochondria in normal oxidative tissues. The sum of FCC(s) for all ATP synthasome and respiratory chain components was found to be around 4, and the value exceeded significantly that for normal tissue (close to 1). In BC cells, the key sites of the regulation of respiration are Complex IV (FCC?=?0.74), ATP synthase (FCC?=?0.61), and phosphate carrier (FCC?=?0.60); these FCC(s) exceed considerably (~10-fold) those for normal oxidative tissues. In human BC cells, the outer mitochondrial membrane is characterized by an increased permeability towards adenine nucleotides, the mean value of the apparent K(m) for ADP being equal to 114.8?±?13.6?μM. Our data support the two-compartment hypothesis of tumor metabolism, the high sum of FCC(s) showing structural and functional organization of mitochondrial respiratory chain and ATP synthasome as supercomplexes in human BC. 相似文献
87.
Shi SY Martin RG Duncan RE Choi D Lu SY Schroer SA Cai EP Luk CT Hopperton KE Domenichiello AF Tang C Naples M Dekker MJ Giacca A Adeli K Wagner KU Bazinet RP Woo M 《The Journal of biological chemistry》2012,287(13):10277-10288
Non-alcoholic fatty liver disease (NAFLD) is becoming the leading cause of chronic liver disease and is now considered to be the hepatic manifestation of the metabolic syndrome. However, the role of steatosis per se and the precise factors required in the progression to steatohepatitis or insulin resistance remain elusive. The JAK-STAT pathway is critical in mediating signaling of a wide variety of cytokines and growth factors. Mice with hepatocyte-specific deletion of Janus kinase 2 (L-JAK2 KO mice) develop spontaneous steatosis as early as 2 weeks of age. In this study, we investigated the metabolic consequences of jak2 deletion in response to diet-induced metabolic stress. To our surprise, despite the profound hepatosteatosis, deletion of hepatic jak2 did not sensitize the liver to accelerated inflammatory injury on a prolonged high fat diet (HFD). This was accompanied by complete protection against HFD-induced whole-body insulin resistance and glucose intolerance. Improved glucose-stimulated insulin secretion and an increase in β-cell mass were also present in these mice. Moreover, L-JAK2 KO mice had progressively reduced adiposity in association with blunted hepatic growth hormone signaling. These mice also exhibited increased resting energy expenditure on both chow and high fat diet. In conclusion, our findings indicate a key role of hepatic JAK2 in metabolism such that its absence completely arrests steatohepatitis development and confers protection against diet-induced systemic insulin resistance and glucose intolerance. 相似文献
88.
89.
Kaseva N Wehkalampi K Strang-Karlsson S Salonen M Pesonen AK Räikkönen K Tammelin T Hovi P Lahti J Heinonen K Järvenpää AL Andersson S Eriksson JG Kajantie E 《PloS one》2012,7(2):e32430
Background
Adults born preterm at very low birth weight (VLBW, <1500 g) have elevated levels of risk factors for cardiovascular diseases and type 2 diabetes. Preliminary observations suggest that this could partly be explained by lower rates of physical activity. The aim of this study was to assess physical activity in healthy young adults born preterm at very low birth weight compared with term-born controls.Methodology/Principal Findings
We studied 94 unimpaired young adults, aged 21–29 years, born at VLBW and 101 age-, sex-, and birth hospital-matched term-born controls from one regional center in Southern Finland. The participants completed a validated 30-item 12-month physical activity questionnaire and the NEO-Personality Inventory based on the Big Five taxonomy, the most commonly used classification of personality traits. Yearly frequency, total time, total volume and energy expenditure of conditioning and non-conditioning leisure-time physical activity (LTPA) and commuting physical activity were compared between VLBW and term-born subjects. A subset of participants underwent dual-energy x-ray absorptiometry for body composition measurement. Data were analyzed by multiple linear regression. Compared with controls, VLBW participants had lower frequency [−38.5% (95% CI; −58.9, −7.7)], total time [−47.4% (95% CI; −71.2, −4.1)], total volume [−44.3% (95% CI; −65.8, −9.2)] and energy expenditure [−55.9% (95% CI; −78.6, −9.4)] of conditioning LTPA when adjusted for age, sex, body mass index, smoking, parental education and personality traits. Adjusting for lean body mass instead of body mass index attenuated the difference. There were no differences in non-conditioning LTPA or commuting physical activity.Conclusions/Significance
Compared with term-born controls, unimpaired VLBW adults undertake less frequent LTPA with lower total time and volume of exercise resulting in lower energy expenditure. Differences in personality that exist between the VLBW and term-born groups do not seem to explain this association. 相似文献90.
Life-history traits are influenced by environmental factors throughout the lifespan of an individual. The relative importance of past versus present environment on individual fitness, therefore, is a relevant question in populations that face the challenge of temporally varying environment. We studied the interacting effects of past and present density on body mass, condition, and survival in enclosure populations of the bank vole (Myodes glareolus) using a reciprocal transplant design. In connection with the cyclic dynamics of natural vole populations, our hypothesis was that individuals born in low-density enclosures would do better overwintering in low-density enclosures than in high-density enclosures and vice versa. Our results show that the effect of summer (past) density was strong especially on survival and body mass. The response of body mass to summer density was negative in both winter (present) density groups, whereas the response of survival probability was nonlinear and differed between the winter density groups. In particular, our data show a trend for higher overwintering success of individuals originating from the lowest summer densities in low winter density and vice versa. We therefore conclude that the capacity of individuals to respond to a change in density was constrained by the delayed density-dependent effects of environment experienced in the past. These effects have the potential to contribute to vole population dynamics. Possible mechanisms mediating the effects of past environment into present performance include both intrinsic and environmental factors. 相似文献