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1.
Oxygen and CO2 exchange were measured concurrently in leaves of shade-grownAlocasia macrorrhiza (L.) G. Don during lightflecks consisting of short periods of high photon flux density (PFD) superimposed on a low-PFD background illumination. Oxygen exchange was measured with a zirconium-oxide ceramic cell in an atmosphere containing 1 600 bar O2 and 350 bar CO2. Following an increase in PFD from 10 to 500 mol photons·m-2·s-1, O2 evolution immediately increased to a maximum rate that was about twice as high as the highest CO2-exchange rates that were observed. Oxygen evolution then decreased over the next 5–10 s to rates equal to the much more slowly increasing rates of CO2 uptake. When the PFD was decreased at the end of a lightfleck, O2 evolution decreased nearly instantaneously to the low-PFD rate while CO2 fixation continued at an elevated rate for about 20 s. When PFD during the lightfleck was at a level that was limiting for steady-state CO2 exchange, then the O2-evolution rate was constant during the lightfleck. This observed pattern of O2 evolution during lightflecks indicated that the maximum rate of electron transport exceeded the maximum rate of CO2 fixation in these leaves. In noninduced leaves, rates of O2 evolution for the first fraction of a second were about as high as rates in fully induced leaves, indicating that O2 evolution and the electron-transport chain are not directly affected by the leaf's induction state. Severalfold differences between induced and noninduced leaves in O2 evolution during a lightfleck were seen for lightflecks longer than a few seconds where the rate of O2 evolution appeared to be limited by the utilization of reducing power in CO2 fixation.Abbreviation PFD
photon flux density (of photosynthetically active radiation) 相似文献
2.
A S Nicholas D A DeBias W Ehrenfeuchter K M England R W England C H Greene D Heilig M Kirschbaum 《BMJ (Clinical research ed.)》1985,291(6487):13-17
Sixty two patients were randomised to be seen by osteopathic physicians for palpation of the thoracic paravertebral soft tissue, T1-T8. Twenty five patients had clinically confirmed acute myocardial infarction. Of the remainder, 22 without known cardiovascular disease served as controls and 15 were placed in an excluded group because of diagnosed cardiovascular disease other than myocardial infarction. Observations were described in predetermined standard terminology. The control group was found to have a low incidence of palpable changes throughout the thoracic dorsum, and these changes were uniformly distributed from T1 to T8. Examination of the group with myocardial infarction disclosed a significantly higher incidence of soft tissue changes (increased firmness, warmth, ropiness, oedematous changes, heavy musculature), confined almost entirely to the upper four thoracic levels. The 15 patients who were excluded from the experimental group because they had various cardiovascular diseases other than myocardial infarction also showed significantly different changes on palpation compared with the group with myocardial infarction. These findings suggest that myocardial infarction is accompanied by characteristic paravertebral soft tissue changes which are readily detected by palpation. 相似文献
3.
4.
The morphogenesis of the "hypertrophied" mormyrid cerebellum was investigated in Pollimyrus (Pisces). Two adults and 36 larvae and young fish raised in captivity were used. Two Gnathonemus petersii adults were taken for comparison. The ontogenetic development of the various cerebellar structures was analysed in inverse chronological order with the aid of serial sagittal and frontal brain sections. Special attention was given to the trilobed corpus cerebelli (C1, C2, C3), the lobi transitorii et caudales, the valvula, the crista cerebelli, the eminentia granularis and the lobus lineae lateralis. 1. The cerebellar structures are of bilateral origin; they develop from the cerebellar and acoustico-lateral "anlage" of the rhombencephalon behind the rhombomesencephalic fissure, either through budding or individualisation and appear between the 4th and 11th day after spawning. The midline fusion of the symmetrical structures is accomplished somewhat later, between the 8th and 23rd days. 2. The cerebellar structures acquire their definitive spatial organisation within 38 days, except for the valvula whose development takes much longer. Recognisable from the 11th day, the valvula upon which ridges are visible from the beginning continues to grow after the 38th day beyond the mesencephalic ventricle, finally overlying the telencephalon frontally and the different rhombencephalic structures caudally. This development, which includes a large antero-lateral folding of the valvula, takes 240 days. 3. Cytological differentiation is just as complex as the general development of the cerebellar structures. Cortical stratification first begins on the 8th to the 11th day in the corpus cerebelli and in the valvula from day 21 to 23 onwards. This differentiation is characterised throughout almost the entire cerebellum by a downward migration of the superficial undifferentiated cells which then constitute the granular layer. In the valvula, the majority of the undifferentiated cells leave the ridges to form a continuous granular layer at the base of the ridges. 4. A differentiation gradient was observed on the antero-posterior axis. 5. In spite of its complexity, the mormyrid cerebellum develops much more rapidly than the cerebellum of the trout. 相似文献
5.
Inken Kirschbaum Joana Straub Stephanie Gest Martin Holtmann Tanja Legenbauer 《Chronobiology international》2018,35(1):101-110
Chronotherapeutics are well established for the treatment of depression and associated sleeping problems in adults. However, effects are still understudied in adolescents. Two pilot studies highlighted the crucial role of sleep when it comes to the treatment of depression, by means of chronotherapeutics, in adolescents. The aim of the present study was to investigate the role of adjunctive wake therapy (WT) in addition to bright light therapy (BLT) with respect to sleep behaviors. In the present study, 62 depressed inpatients (aged 13–18 years; diagnosed with Beck Depression Inventory Revision) were randomly assigned to two groups: BLT only (BLT-group) and a combination of BLT and WT (COMB-group). After one night of WT adolescents in the COMB-group revealed longer sleep durations, time in bed, advanced sleep onset, less wakes during night and an improved sleep efficiency. However, one night of WT plus BLT had no additional effect on sleep parameters compared with BLT-group in the long run. Therefore, future studies should assess whether more nights of WT might lead to more sustainable effects. 相似文献
6.
Background
Influenza pandemic remains a serious threat to human health. Viruses of avian origin, H5N1, H7N7 and H9N2, have repeatedly crossed the species barrier to infect humans. Recently, a novel strain originated from swine has evolved to a pandemic. This study aims at improving our understanding on the pathogenic mechanism of influenza viruses, in particular the role of non-structural (NS1) protein in inducing pro-inflammatory and apoptotic responses.Methods
Human lung epithelial cells (NCI-H292) was used as an in-vitro model to study cytokine/chemokine production and apoptosis induced by transfection of NS1 mRNA encoded by seven infleunza subtypes (seasonal and pandemic H1, H2, H3, H5, H7, and H9), respectively.Results
The results showed that CXCL-10/IP10 was most prominently induced (> 1000 folds) and IL-6 was slightly induced (< 10 folds) by all subtypes. A subtype-dependent pattern was observed for CCL-2/MCP-1, CCL3/MIP-1α, CCL-5/RANTES and CXCL-9/MIG; where induction by H5N1 was much higher than all other subtypes examined. All subtypes induced a similar temporal profile of apoptosis following transfection. The level of apoptosis induced by H5N1 was remarkably higher than all others. The cytokine/chemokine and apoptosis inducing ability of the 2009 pandemic H1N1 was similar to previous seasonal strains.Conclusions
In conclusion, the NS1 protein encoded by H5N1 carries a remarkably different property as compared to other avian and human subtypes, and is one of the keys to its high pathogenicity. NCI-H292 cells system proves to be a good in-vitro model to delineate the property of NS1 proteins.7.
Sarah Patterson Patricia Moran Elissa Epel Elizabeth Sinclair Margaret E. Kemeny Steven G. Deeks Peter Bacchetti Michael Acree Lorrie Epling Clemens Kirschbaum Frederick M. Hecht 《PloS one》2013,8(7)
Objective
The level of T cell activation in untreated HIV disease is strongly and independently associated with risk of immunologic and clinical progression. The factors that influence the level of activation, however, are not fully defined. Since endogenous glucocorticoids are important in regulating inflammation, we sought to determine whether less optimal diurnal cortisol patterns are associated with greater T cell activation.Methods
We studied 128 HIV-infected adults who were not on treatment and had a CD4+ T cell count above 250 cells/µl. We assessed T cell activation by CD38 expression using flow cytometry, and diurnal cortisol was assessed with salivary measurements.Results
Lower waking cortisol levels correlated with greater T cell immune activation, measured by CD38 mean fluorescent intensity, on CD4+ T cells (r = −0.26, p = 0.006). Participants with lower waking cortisol also showed a trend toward greater activation on CD8+ T cells (r = −0.17, p = 0.08). A greater diurnal decline in cortisol, usually considered a healthy pattern, correlated with less CD4+ (r = 0.24, p = 0.018) and CD8+ (r = 0.24, p = 0.017) activation.Conclusions
These data suggest that the hypothalamic-pituitary-adrenal (HPA) axis contributes to the regulation of T cell activation in HIV. This may represent an important pathway through which psychological states and the HPA axis influence progression of HIV. 相似文献8.
A Scuto M Kirschbaum R Buettner M Kujawski J M Cermak P Atadja R Jove 《Cell death & disease》2013,4(5):e635
We explored the activity of SIRT1 activators (SRT501 and SRT2183) alone and in combination with panobinostat in a panel of malignant lymphoid cell lines in terms of biological and gene expression responses. SRT501 and SRT2183 induced growth arrest and apoptosis, concomitant with deacetylation of STAT3 and NF-κB, and reduction of c-Myc protein levels. PCR arrays revealed that SRT2183 leads to increased mRNA levels of pro-apoptosis and DNA-damage-response genes, accompanied by accumulation of phospho-H2A.X levels. Next, ChIP assays revealed that SRT2183 reduces the DNA-binding activity of both NF-κB and STAT3 to the promoter of GADD45G, which is one of the most upregulated genes following SRT2183 treatment. Combination of SRT2183 with panobinostat enhanced the anti-growth and anti-survival effects mediated by either compound alone. Quantitative-PCR confirmed that the panobinostat in combination with SRT2183, SRT501 or resveratrol leads to greater upregulation of GADD45G than any of the single agents. Panobinostat plus SRT2183 in combination showed greater inhibition of c-Myc protein levels and phosphorylation of H2A.X, and increased acetylation of p53. Furthermore, EMSA revealed that NF-κB binds directly to the GADD45G promoter, while STAT3 binds indirectly in complexes with NF-κB. In addition, the binding of NF-κB/STAT3 complexes to the GADD45G promoter is inhibited following panobinostat, SRT501 or resveratrol treatment. Moreover, the combination of panobinostat with SRT2183, SRT501 or resveratrol induces a greater binding repression than either agent alone. These data suggest that STAT3 is a corepressor with NF-κB of the GADD45G gene and provides in vitro proof-of-concept for the combination of HDACi with SIRT1 activators as a potential new therapeutic strategy in lymphoid malignancies. 相似文献
9.
Esther H. D. Carlitz Robert Miller Clemens Kirschbaum Wei Gao Daniel C. H?nni Carel P. van Schaik 《PloS one》2016,11(4)
Non-human primates face major environmental changes due to increased human impacts all over the world. Although some species are able to survive in certain landscapes with anthropogenic impact, their long-term viability and fitness may be decreased due to chronic stress. Here we assessed long-term stress levels through cortisol analysis in chimpanzee hair obtained from sleeping nests in northwestern Uganda, in order to estimate welfare in the context of ecotourism, forest fragmentation with human-wildlife conflicts, and illegal logging with hunting activity (albeit not of primates), compared with a control without human contact or conflict. Concerning methodological issues, season [F(2,129) = 37.4, p < 0.0001, r2 = 0.18] and the age of nests [F(2,178) = 20.3, p < 0.0001, r2 = 0.11] significantly predicted hair cortisol concentrations (HCC). With regard to effects of anthropogenic impacts, our results neither showed elevation of HCC due to ecotourism, nor due to illegal logging compared to their control groups. We did, however, find significantly increased HCC in the fragment group compared to chimpanzees living in a nearby intact forest [F(1,88) = 5.0, p = 0.03, r2 = 0.20]. In conclusion, our results suggest that hair cortisol analysis is a powerful tool that can help understanding the impact of anthropogenic disturbances on chimpanzee well-being and could be applied to other great ape species. 相似文献
10.
Comparative gene-expression analysis 总被引:8,自引:0,他引:8