Seasonal variation in respiration of 1-year-old shoots of scots pine exposed to elevated carbon dioxide and temperature for 4 years

Sixteen 20-year-old Scots pine (Pinus sylvestris L.) trees growing in the field were enclosed for 4 years in environment-controlled chambers that maintained: (1) ambient conditions (CON); (2) elevated atmospheric CO2 concentration (ambient + 350 micro mol mol-1; EC); (3) elevated temperature (ambient +2-6 degrees C; ET); or (4) elevated CO2 and elevated temperature (ECT). The dark respiration rates of 1-year-old shoots, from which needles had been partly removed, were measured over the growing season in the fourth year. In all treatments, the temperature coefficient of respiration, Q10, changed with season, being smaller during the growing season than at other times. Respiration rate varied diurnally and seasonally with temperature, being highest around mid-summer and declining gradually thereafter. When measurements were made at the temperature of the chamber, respiration rates were reduced by the EC treatment relative to CON, but were increased by ET and ECT treatments. However, respiration rates at a reference temperature of 15 degrees C were reduced by ET and ECT treatments, reflecting a decreased capacity for respiration at warmer temperatures (negative acclimation). The interaction between season and treatment was not significant. Growth respiration did not differ between treatments, but maintenance respiration did, and the differences in mean daily respiration rate between the treatments were attributable to the maintenance component. We conclude that maintenance respiration should be considered when modelling respiratory responses to elevated CO2 and elevated temperature, and that increased atmospheric temperature is more important than increasing CO2 when assessing the carbon budget of pine forests under conditions of climate change.     

Light and water-use efficiencies of pine shoots exposed to elevated carbon dioxide and temperature

An automatic gas exchange system was used to continuously measure water and carbon fluxes of attached shoots of Scots pine trees (Pinus sylvestris L.) grown in environment-controlled chambers for a 3-year period (1998-2000) and exposed to either normal ambient conditions (CON), elevated CO2 (+350 micro mol mol-1; EC), elevated temperature (+2-6 degrees C; ET) or a combination of EC and ET (ECT). EC treatment enhanced the mean daily total carbon flux per unit projected needle area (Fc.d) by 17-21 %, depending on the year. This corresponds to a 16-24 % increase in light-use efficiency (LUE) based on incident photosynthetically active radiation. The EC treatment reduced the mean daily total water flux (Fw.d) by 1-12 %, corresponding to a 13-35 % increase in water-use efficiency (WUE). The ET treatment increased Fc.d by 10-18 %, resulting in an 8-19 % increase in LUE, and Fw.d by 48-74 %, resulting in a reduction of WUE by 19-34 %. There was no interaction between CO2 and temperature elevation in connection with either carbon or water fluxes, as the carbon flux responded similarly in both ECT and EC, while the water flux in the ECT treatment was similar to that in ET. Regressions indicated that the increase in maximum LUE was greater with increasing air temperature, whereas changes in WUE were related only to high vapour pressure deficit. Furthermore, changes in LUE and WUE caused by ECT treatment displayed strong diurnal and seasonal variation.     

Lupane‐ and Friedelane‐Type Triterpenoids from Celastrus stylosus

Two new triterpenoids, 30‐hydroxylup‐20(29)‐ene 3β‐caffeate ( 1 ) and 24‐nor‐friedelan‐6α,10‐dihydroxy‐1,2‐dioxo‐4,7‐dien‐29‐oic acid ( 2 ), together with eight known compounds 3 – 10 , were isolated from the roots of Celastrus stylosus. The structures of these compounds were elucidated on the basis of spectroscopic analyses. To the best of our knowledge, this represents the first study on the chemical constituents of C. stylosus. The antiproliferative activities of the triterpenoids against six human cancer cell lines (PANC‐1, A549, PC‐3, HepG2, SGC‐7901, and HCCLM3) were evaluated. Compounds 3, 4 , and 10 exhibited comparable activities against PC‐3 and HCCLM3 cell lines as the positive control taxol.     

Nonrigid Registration Regularized by Shape Information: Application to Atlas Construction of Cardiac CT Images

Cardiac atlases play an important role in the computer-aided diagnosis of cardiovascular diseases, in particular they need to deal with large and highly variable image datasets. In this paper, we propose a new nonrigid registration algorithm incorporating shape information, to produce comprehensive atlases. For one thing, the multiscale gradient orientation features of images are combined to form the construction of multifeature mutual information. Additionally, the shape information of multiple-objects in images is incorporated into the cost function for registration. We demonstrate the merits of the new registration algorithm on the 3D data sets of 15 patients. The experimental results show that the new registration algorithm can outperform the conventional intensity-based registration method. The obtained atlas can represent the cardiac structures more accurately.     

Efficacy of Chromium(III) Supplementation on Growth,Body Composition,Serum Parameters,and Tissue Chromium in Rats

Chromium(III) is often claimed to have a positive effect on body composition, while the responses in researches with supplementation of different chemical form of chromium are various and inconsistent. We have studied the effects of 6 weeks of treatment with three different forms of chromium (300 μg/kg) as chromium chloride, chromium tripicolinate, and chromium nanocomposite (CrNano) on growth, body composition, serum parameters, and tissue chromium in rats. The supplementataion of CrNano significantly increased average daily gain, food efficiency, and lean body mass and decreased fat mass and body fat proportion and serum levels of glucose, urea nitrogen, triglyceride, and insulin. Chromium contents in liver, kidney, and hind leg muscle were increased significantly with the addition of CrNano in diet. The results indicate that chromium nanocomposite has higher efficacy on growth and body composition compared to the traditional chromium agents.     

Phosphatidylinositol 3-kinase/protein kinase B pathway stabilizes DNA methyltransferase I protein and maintains DNA methylation

DNA methylation, which affects gene expression and chromatin stability, is catalyzed by DNA methyltransferases (DNMTs) of which DNMT1 possesses most abundant activity. PI3K/PKB pathway is an important pathway involved in cell proliferation, viability, and metabolism and often disrupted in cancer. Here we investigated the impact of PKB on DNMT1 and DNA methylation. Positive correlation between PKB-Ser473-phosphorylation and DNMT1 protein level in 17 human cell lines (p<0.01) and in 27 human bladder cancer tissues (p<0.05) was found. With activator, inhibitor, siRNA and constitutively active or dominant-negative plasmids of PKB, we found that PKB increased the protein level of DNMT1 without coordinate mRNA change, which was specific rather than due to cell-cycle change. PKB enhanced DNMT1 protein stability independent of de novo synthesis of any protein, which was attributed to down-regulation of N-terminal-120-amino-acids-dependent DNMT1 degradation via ubiquitin-proteasome pathway. Gsk3beta inhibitor rescued the decrease of DNMT1 by PKB inhibition, suggesting that Gsk3beta mediated the stabilization of DNMT1 by PKB. Then role of PKB regulating DNMT1 was investigated. Inhibition of PKB caused observable DNA hypomethylation and chromatin decondensation and DNMT1 overexpression partially reversed cell growth inhibition by PKB inhibition. In conclusion, our results suggested that PKB enhanced DNMT1 stability and maintained DNA methylation and chromatin structure, which might contribute to cancer cell growth.     

A Putative Adhesin-encoding Gene AOL_s00007g5 is involved in the Mycelial Growth and Development of Nematode-trapping Fungus Arthrobotrys oligospora

Applied Biochemistry and Microbiology - Arthrobotrys oligospora is one of the most commonly studied fungi that can form abundant traps to capture and consume nematodes at the parasitic stage....