Cuttings of Populus cathayana Rehd, originating from three triploid and one diploid populations with the same parents but different gamete origins, were used to examine physiological responses to drought stress and rewatering by exposure to three progressive water regimes. Progressive drought stress significantly decreased the leaf relative water content (RWC), photosynthesis, and chlorophyll fluorescence parameters, and increased the relative electrolyte leakage, malondialdehyde (MDA), free proline (Pro), and antioxidant enzymes, such as superoxide dismutase, peroxidase, and catalase, in the four populations evaluated. However, compared to the diploid population, triploid populations showed lower relative electrolyte leakage and MDA, higher RWC and Pro content, and more efficient photosynthesis and antioxidant systems under the same water regime. Our data indicated that triploid populations possessed more efficient protective mechanisms than that of diploid population with gradually increasing drought stress. Moreover, some triploid genotypes were less tolerant to water stress than that of diploids due to large intrapopulation overlap., T. Liao, Y. Wang, C. P. Xu, Y. Li, X. Y. Kang., and Obsahuje bibliografii
5-hydroxytryptamine (5-HT) is involved in the stress-induced alteration of colonic functions, specifically motility and secretion, but its precise mechanisms of regulation remain unclear. In the present study, we have investigated the effects of 5-HT on rat colonic mucosal secretion after acute water immersion restraint stress, as well as the underlying mechanism of this phenomenon, using short circuit current recording (ISC), real-time polymerase chain reaction, Western blot analysis, and enzyme-linked immunosorbance assays. After 2 h of water immersion restraint stress, the baseline ISC and 5-HT-induced ISC responses of the colonic mucosa were significantly increased. Pretreatment with selective 5-HT4 receptor antagonist, SB204070, inhibited the 5-HT-induced colonic ISC response by 96 % in normal rats and 91.2 % in acute-stress rats. However, pretreatment with the selective antagonist of 5-HT3 receptor, MDL72222 or Y-25130, had no obvious effect on 5-HT-induced ISC responses under either set of conditions. Total protein expression of both the mucosal 5-HT3 receptors and the 5-HT4 receptors underwent no significant changes following acute stress. Both colonic basal cAMP levels and foskolin-induced ISC responses were significantly enhanced in acute stress rats. 5-HT significantly enhanced the intracellular cAMP level via 5-HT4 receptors in the colonic mucosa from both control and stressed animals, and 5-HT-induced cAMP increase in stressed rats was not more than that in control rats. Taken together, the present results indicate that acute water immersion restraint stress enhances colonic secretory responses to 5-HT in rats, a process in which increased cellular cAMP accumulation is involved., Y. Li, L. S. Li, X. L. Zhang, Y. Zhang, J. D. Xu, J. X. Zhu., and Obsahuje bibliografii
Halomicronema hongdechloris is a chlorophyll (Chl) f-producing cyanobacterium. Chl f biosynthesis is induced under far-red light, extending its photosynthetically active radiation range to 760 nm. In this study, PSI complexes were isolated and purified from H. hongdechloris, grown under white light (WL) and far-red light (FR), by a combination of density gradient ultracentrifugation and chromatographic separation. WL-PSI showed similar pigment composition as that of Synechocystis 6803, using Chl a in the reaction center. Both Chl a and f were detected in the FR-PSI, although Chl f was a minor component (~8% of total Chl). The
FR-PSI showed a maximal fluorescence emission peak of 750 nm at 77 K, which is red-shifted ~20 nm compared to the 730 nm recorded from the WL-PSI. The absorption peaks of P700 for WLPSI and FR-PSI were 699 nm and 702 nm, respectively. The function of Chl f in FR-PSI is discussed., Y. Li, N. Vella, M. Chen., and Obsahuje bibliografické odkazy
Extremely low-frequency magnetic field (ELF-MF) has been suggested to influence the cognitive capability but this should be dynamically evaluated in a longitudinal study. Previous training can affect performance, but the influence under magnetic field is unclear. This study aims to evaluate the effects of previous training and ELF-MF exposure on learning and memory using the Morris water maze (MWM). Sprague-Dawley rats were subjected to MWM training, ELF-MF exposure (50 Hz, 100 μT), or ELF-MF exposure combined with MWM training for 90 days. Normal rats were used as controls. The MWM was used to test. The data show that the rats exposed to training and ELF-MF with training performed better on spatial acquisition when re-tested. However, during the probe trial the rats showed no change between the training phase and the test phase. Compared with the control group, the ELF-MF group showed no significant differences. These results confirm that previous training can improve the learning and memory capabilities regarding spatial acquisition in the MWM and this effect can last for at least 90 days. However, this improvement in learning and memory capabilities was not observed during the probe trial. Furthermore, ELF-MF exposure did not interfere with the improvement in learning and memory capabilities., Y. Li, C. Zhang, T. Song., and Obsahuje bibliografii
Vegetation in grasslands is changing at an unprecedented rate. In the Nebraska Sandhills, this shift is attributed in part to encroachment of the woody species Juniperus virginiana. We investigated changes in resource availability and their feedback on seasonal trends in photosynthetic characteristics of J. virginiana trees scattered in open grasslands vs. a dense 57-year-old stand. Dense stand exhibited lower volumetric soil water content, NH4+, NO3-, and δ13C, as well as foliage δ13C, δ15N, and N content, compared to grasslands. Water potential was higher in trees in grasslands compared to dense stand. J. virginiana in dense stand exhibited similar trends to trees in grasslands for net photosynthetic rate (PN), stomatal conductance, transpiration, maximum photochemical efficiency of PSII, maximum carboxylation velocity, and maximum rate of electron transport. PN peaked early summer and declined in the fall, with trees in open grasslands lagging behind those in dense stand. Plasticity of this species may place it at a competitive advantage in the Sandhills, further altering grasslands vegetation and ecosystem processes., J. Msanne, T. Awada, N. M. Bryan, W. Schacht, R. Drijber, Y. Li, X. Zhou, J. Okalebo, D. Wedin, J. Brandle, J. Hiller., and Obsahuje bibliografii
There is a great uncertainty about the effect of land use change on grassland ecosystem in the Tibetan Plateau. Net ecosystem carbon exchange (NEE) was measured for native alpine meadow with winter grazing (NAM), abandoned cropland/pasture (APL), perennial Elymus nutans (PEN), and annual oat pasture (AO) on the Tibetan plateau, during the growing seasons in 2009 and 2010 using a transparent chamber technique (Licor-6400). AO significantly decreased annual average NEE by 21.6, 23.7, and 15.7% compared to PEN, NAM, and APL during the growing season in 2010. Compared to PEN, NAM, and APL, AO significantly decreased average ecosystem respiration (Re) by 21.1, 52.3, and 39.3%, respectively, during the growing season in 2009. Soil moisture and total aboveground and belowground biomass together explained 39.6% of NEE variation and 71% in gross primary productivity variation. Soil moisture and belowground biomass explained about 83.1% of the Re variation. Our results indicated that it is possible to convert APL to PEN in the region because it could result in a higher NEE together with higher forage production compared to AO., C.-Y. Luo, X.-X. Zhu, S.-P. Wang, S.-J. Cui, Z.-H. Zhang, X.-Y. Bao, L. Zhao, Y. Li, X.-Q. Zhao., and Obsahuje seznam literatury
Apolipoprotein J (clusterin) is a component of high-density lipoproteins, the high level of which is reversely correlated with the risk of coronary heart disease. In addition, it exerts anti-inflammatory and anti-apoptotic effects on endothelial cells and inhibits smooth muscle cell migration and proliferation, indicating that it may play a protective role in cardiovascular disease. However, the exact mechanisms by which this occurs remain unclear. This study aimed to clarify these underlying protective mechanisms by researching the inhibitory effects of apolipoprotein J via the NOD-like receptor protein 3 pathway on the inflammation induced by cholesterol crystals in THP‑1 macrophages. In culture, THP-1 macrophages were infected with adenoviral vectors containing apolipoprotein J genes and subsequently treated with cholesterol crystals. The inflammatory cytokines interleukin‑1β, interleukin 18 and tumour necrosis factor α were quantitatively measured with ELISA kits. NOD-like receptor protein 3, cysteinyl aspartate specific proteinase 1 and interleukin 1β were evaluated by Western blot and PCR analysis. As a result, apolipoprotein J expression was found to remarkably decrease the levels of inflammatory cytokines, including tumour necrosis factor α, interleukin 18 and interleukin 1β, secreted by THP‑1 macrophages. It was also found capable of inhibiting the levels of NOD-like receptor protein 3, cysteinyl aspartate-specific proteinase 1 and interleukin 1β both at the protein and mRNA levels. In the current study, we revealed that over-expression of apolipoprotein J attenuated the inflammation induced by cholesterol crystals through inhibition of the NOD-like receptor protein 3 inflammasome pathway.
Xerophytic stomatal traits may help plants maintain photosynthetic rates under water deficit; however, such adaptations are not well understood. A pot experiment was conducted with two winter wheat cultivars (Pubing 143, Zhengyin 1) during the grain-filling period. Net photosynthetic rate (PN) and chlorophyll (Chl) content were significantly less affected by water deficit in Pubing 143 than that in Zhengyin 1, and the variation in both PN and Chl content were more stable in spikes compared to flag leaves. At 18 days after anthesis, stomatal conductance of spikes in Pubing 143 were 28% lower than that of the control, while transpiration rate was 34% lower in Zhengyin 1 under water deficit. We provided the first evidence of amphistomatous stomata on the lemma of winter wheat spikes through scanning electron microscopic observations. The finding of the amphistomatous stomata is an important contribution to stomatal distribution and may help explain how wheat spikes can maintain high photosynthetic rates even under drought conditions., H. Ding, D. Liu, X. Liu, Y. Li, J. Kang, J. Lv, G. Wang., and Obsahuje bibliografii
Small rainfall events (≤ 5 mm) have short intervals, but account for a large proportion of the annual rainfall frequency in arid lands. To explore possible strategies used by desert plants to utilize the small rainfall events, we investigated the photosynthetic responses of 28 species to 1 mm and 6 mm of simulated rainfall in the Junggar Basin, northwest China. The species were grouped into four plant functional types: short-life-cycle herbs, long-life-cycle herbs, non-phreatophyte shrubs, and phreatophyte shrubs. The results showed that the net photosynthetic rate, stomatal conductance, and transpiration rate increased in most of the herbs, but they responded differently to the rainfall treatments. However, the water-use efficiency did not significantly differ after 1 and 6 mm rainfall treatments in most of the shrubs. The maximum water absorption by leaves and the percentage increase of a leaf water content (LWC) were higher in the herbs than those in the shrubs. Plants with dense trichomes had the highest LWC. The results suggested that the desert plants benefited from the
micro-environment humidity provided by the small rainfall events., Y. Wu, X. J. Zheng , Y. Li., and Obsahuje seznam literatury
The colorectum (late distal colon) is innervated by the sympathetic nervous system, and many colorectal diseases are related to disorders of the sympathetic nervous system. The sympathetic regulation of colorectal ion transport is rarely reported. The present study aims to investigate the effect of norepinephrine (NE) in the normal and catecholamine-depleted condition to clarify the regulation of the sympathetic adrenergic system in ion transport in the rat colorectum. NE-induced ion transport in the rats colorectum was measured by short-circuit current (Isc) recording; the expression of β-adrenoceptors and NE transporter (NET) were quantified by real-time PCR, and western blotting. When the endogenous catecholamine was depleted by reserpine, the baseline Isc in the colorectum was increased significantly comparing to controls. NE evoked downward ∆Isc in colorectum of treated rats was 1.8-fold of controls. The expression of β 2 -adrenoceptor protein in the colorectal mucosa was greater than the control, though the mRNA level was reduced. Ho wever, NET expression was significantly lower in catecholamine-depleted rats compared to the controls. In conclusion, the sympathetic nervous system plays an important role in regulating basal ion transport in the colorectum. Disorders of sympathe tic neurotransmitters result in abnormal ion transport, β-adrenoceptor and NET are involved in the process., X. Zhang, Y. Li, X. Zhang, Z. Duan, J. Zhu., and Obsahuje bibliografii