The time variability of evapotranspiration and soil water storage in long series of rainfall-runoff process

Natural variability, i. e. climatic oscillation, influences the development of vegetation in the annual cycle. At the same time it creates the conditions for the changes of the vegetation cover even in the scale of centuries. This is the phenomenon, which causes the variation or tendencies in evapotranspiration demands and consequently of water storage regime, and its long scale change is sometimes disregarded. The simulation of rainfall-runoff process has been used for the re-evaluation of the assumed evapotranspiration demand due to the developing vegetation cover and of groundwater storage in the catchments. The simulations provide the results, which illustrate the dominant role of transpiration in comparison with other components of evapotranspiration. The simulations also illustrate the interaction between evapotranspiration and groundwater storage. Additionally, the modelling confirms that it could be useful to compare the parameters for the recession process of simulated sub-surface water storage with the decreases of observed outflow of springs and/or with the course of water levels in the bore holes.     

Synchrotron-based X-ray fluorescence imaging of human cells labeled with CdSe quantum dots

Synchrotron-based X-ray fluorescence (S-XRF) is a powerful technique for imaging the distribution of many biologically relevant elements as well as of “artificial” elements deliberately introduced into tissues and cells, for example, through functionalized nanoparticles. In this study, we explored the potential of S-XRF for chemical nanoimaging (100 nm spatial resolution, nanoXRF) of human cells through the use of functionalized CdSe/ZnS quantum dots (QDs). We used a commercially available QD-secondary antibody conjugate to label the cancer marker HER2 (human epidermal growth factor receptor 2) on the surface of SKOV3 cancer cells and β-tubulin, a protein associated with cytoskeleton microtubules. We set up samples with epoxy inclusion and intracellular labeling as well as samples without epoxy inclusion and with surface labeling. Epoxy inclusion, also used in electron microscopy, has the advantage of preserving cell morphology and guaranteeing long-term stability. QDs proved to be suitable probes for nanoXRF due to the Se emission band, which is not in close proximity to any other emission band, and the signal specificity, which is preserved in both types of labeling. Therefore, nanoXRF using QD-based markers can be very effective at colocalizing specific intracellular targets with elements naturally present in the cell and may complement confocal fluorescence microscopy in a synergistic fashion.     

Balancing algal toxicity and turbidity with predation risk in the three-spined stickleback

Prey may select suboptimal habitat to alleviate predation risk. Algal blooms and turbidity are potentially harmful to prey in aquatic environments, but can provide refugia against predation, given that predators avoid such conditions. Using a flow-through aquarium, we experimentally studied the habitat choice of the three-spined stickleback (Gasterosteus aculeatus L.) provided with toxic and non-toxic bloom-forming cyanobacteria and green flagellate-induced turbidity in the presence and absence of a chemical predator signal from a perch (Perca fluviatilis L.). We investigated whether sticklebacks separate between different algal strains and between turbid and clear water, and whether they are able to use algal toxicity and turbidity as shelter against predators. Sticklebacks preferred the toxic over the non-toxic Nodularia spumigena (Mertens) habitat in the presence of a predator signal, whereas no differences in times spent in the two habitats were detected when the predator signal was absent. There was a tendency for sticklebacks to prefer clear over turbid water in the absence of a predator signal, but no differences were found when the predator signal was present. Our results suggest that the three-spined stickleback is not fully adapted to the cyanobacterial blooms and turbidity caused by the recent eutrophication of the Baltic Sea. However, the predator-induced shifts in habitat choice are also consistent with the hypothesis that sticklebacks use algal toxicity and turbidity as shelters against predation, since these factors are likely to have only minor fitness consequences for sticklebacks.     

Morphological and chemical components of resistance to pod borer, Helicoverpa armigera in wild relatives of pigeonpea

Host plant resistance is an important component for minimizing the losses due to the pod borer, Helicoverpa armigera, which is the most devastating pest of pigeonpea. An understanding of different morphological and biochemical components of resistance is essential for developing strategies to breed for resistance to insect pests. Therefore, we studied the morphological and biochemical components associated with expression of resistance to H. armigera in wild relatives of pigeonpea to identify accessions with a diverse combination of characteristics associated with resistance to this pest. Among the wild relatives, oviposition non-preference was an important component of resistance in Cajanus scarabaeoides, while heavy egg-laying was recorded on C. cajanifolius (ICPW 28) and Rhynchosia bracteata (ICPW 214). Accessions belonging to R. aurea, C. scarabaeoides, C. sericeus, C. acutifolius, and Flemingia bracteata showed high levels of resistance to H. armigera, while C. cajanifolius was as susceptible as the susceptible check, ICPL 87. Glandular trichomes (type A) on the calyxes and pods were associated with susceptibility to H. armigera, while the non-glandular trichomes (trichome type C and D) were associated with resistance to this insect. Expression of resistance to H. armigera was also associated with low amounts of sugars and high amounts of tannins and polyphenols. Accessions of wild relatives of pigeonpea with non-glandular trichomes (type C and D) or low densities of glandular trichomes (type A), and high amounts of polyphenols and tannins may be used in wide hybridization to develop pigeonpea cultivars with resistance to H. armigera. Handling editor: Robert Glinwood     

茯苓多糖在治疗肿瘤方面的临床研究进展

茯苓在药物化学、药理学、临床应用等方面有很高的使用价值。本文主要论述了茯苓药用的主要化学成分,在抗肿瘤和增强免疫力方面的作用,并对茯苓的前景进行了展望,为茯苓的进一步开发提供依据。     

Conflicting selection on diaspore traits limits the evolutionary potential of seed dispersal by ants

Conflicts of selection on diaspore traits throughout the dispersal cycle can limit the evolutionary consequences of seed dispersal. However, these conflicts have never been investigated in directed dispersal systems. We explored conflicts of selection through life stages of dispersal in the myrmecochorous herb Helleborus foetidus. Seeds are subject to two contrasting partial selective scenarios. Undispersed seeds are subject to positive directional selection on seed size characters, whereas seeds dispersed are subject to stabilizing selection for size. In both scenarios, seedling establishment determined the magnitude and direction of selection. This does not reflect ant preferences for seed size. However, total selection still depends largely on ant activity, as ants control the relative importance of each selective scenario. We advocate the use of analytical approaches combining multiplicative fitness and microenvironment‐specific selection to more realistically estimate the realized selection on traits functional during several life stages. This approach may be extended to any organism dispersing offspring to different environments.     

Allosteric modulation of adenosine receptors

Allosteric modulators for adenosine receptors may have potential therapeutic advantage over orthosteric ligands. Allosteric enhancers at the adenosine A₁ receptor have been linked to antiarrhythmic and antilipolytic activity. They may also have therapeutic potential as analgesics and neuroprotective agents. A₃ allosteric enhancers are postulated to be useful against ischemic conditions or as antitumor agents. In this review, we address recent developments regarding the medicinal chemistry of such compounds. Most efforts have been and are directed toward adenosine A₁ and A₃ receptors, whereas limited or no information is available for A_2A and A_2B receptors. We also discuss some findings, mostly receptor mutation studies, regarding localization of the allosteric binding sites on the receptors.     

Development of analytical methods for NMR spectra and application to a 13C toxicology study

Metabolomics offers the potential to assess the effects of toxicants on metabolite levels. To fully realize this potential, a robust analytical workflow for identifying and quantifying treatment-elicited changes in metabolite levels by nuclear magnetic resonance (NMR) spectrometry has been developed that isolates and aligns spectral regions across treatment and vehicle groups to facilitate analytical comparisons. The method excludes noise regions from the resulting reduced spectra, significantly reducing data size. Principal components analysis (PCA) identifies data clusters associated with experimental parameters. Cluster-centroid scores, derived from the principal components that separate treatment from vehicle samples, are used to reconstruct the mean spectral estimates for each treatment and vehicle group. Peak amplitudes are determined by scanning the reconstructed mean spectral estimates. Confidence levels from Mann–Whitney order statistics and amplitude change ratios are used to identify treatment-related changes in peak amplitudes. As a demonstration of the method, analysis of ¹³C NMR data from hepatic lipid extracts of immature, ovariectomized C57BL/6 mice treated with 30 μg/kg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or sesame oil vehicle, sacrificed at 72, 120, or 168 h, identified 152 salient peaks. PCA clustering showed a prominent treatment effect at all three time points studied, and very little difference between time points of treated animals. Phenotypic differences between two animal cohorts were also observed. Based on spectral peak identification, hepatic lipid extracts from treated animals exhibited redistribution of unsaturated fatty acids, cholesterols, and triacylglycerols. This method identified significant changes in peaks without the loss of information associated with spectral binning, increasing the likelihood of identifying treatment-elicited metabolite changes.     

黑柄炭角菌的研究进展

黑柄炭角菌[Xylaria nigripes(Kl.)Sacc.]是一种生长于白蚁废巢的珍稀药用菌。文中对该菌的生物学特性、化学成分、药理作用等几个方面的研究进展进行了综述,并提出了下一步的研究重点和应用展望。     

Granular activated carbon single-chamber microbial fuel cells (GAC-SCMFCs): A design suitable for large-scale wastewater treatment processes

As an emerging biotechnology capable of removing contaminants and producing electricity, microbial fuel cells (MFCs) hold a promising future in wastewater treatment. However, several main problems, including the high internal resistance (R_in), low power output, expensive material, and complicated configuration have severely hindered the large-scale application of MFCs. The study targeted these challenges by developing a novel MFC system, granular activated carbon single-chamber MFC, termed as GAC-SCMFC. The batch tests showed that GAC was a good substitute for carbon cloth and GAC-SCMFCs generated high and stable power outputs compared with the traditional two-chamber MFCs (2CMFCs). Critical operational parameters (i.e. wastewater substrate concentrations, GAC amount, electrode distance) affecting the performance of GAC-SCMFCs were examined at different levels. The results showed that the R_in gradually decreased from 60 Ω to 45 Ω and the power output increased from 0.2 W/m³ to 1.2 W/m³ when the substrate concentrations increased from 100 mg/L to 850 mg/L. However, at high concentrations of 1000–1500 mg/L, the power output leveled off. The R_in of MFCs decreased 50% when the electrode distance was reduced from 7.5 cm to 1 cm. The highest power was achieved at the electrode distance of 2 cm. The power generation increased with more GAC being added in MFCs due to the higher amount of biomass attached. Finally, the multi-anode GAC-SCMFCs were developed to effectively collect the electrons generated in the GAC bed. The results showed that the current was split among the multiple anodes, and the cathode was the limiting factor in the power production of GAC-SCMFCs.