A Yeast Bioassay for Androgenic and Anti-Androgenic Compounds Based on the NH2- and COOH-Terminal Interaction of Androgen Receptor

Androgenic compounds induce an interaction between the NH₂- and COOH-terminal regions (N–C interaction) of androgen receptor (AR). We describe a rapid yeast bioassay for androgenic and anti-androgenic compounds based on androgen-dependent β-catenin-enhanced N–C interaction. The bioassay was also effective at detecting compounds that inhibit the N–C interaction in ways that do not involve binding to the ligand-binding domain.     

Effects of n–3 Polyunsaturated Fatty Acids and Lectins on Immunoglobulin Production by Spleen Lymphocytes of Sprague-Dawley Rats

We examined the effects of n-3 polyunsaturated fatty acid (PUFA), such as α-linolenic (α -LA), eicosapentaenoic (EPA), and docosahexaenoic acid (DHA) on immunoglobulin (Ig) production by spleen lymphocytes of Sprague-Dawley rats, n-3 polyunsaturated fatty acid (PUFA) strongly inhibited the production of IgA and IgM and that of IgG weakly at 100 μΜ. When the lymphocytes were treated with n-3 PUFA in the presence of other inhibitory biomaterials such as lectins, some PUFA attenuated their inhibitory effect on Ig production. In the presence of concanavalin A (ConA), all n-3 PUFA attenuated the inhibitory effect of ConA on the production of IgM or IgG but increased its inhibition of IgA synthesis. Thus, the interaction of n-3 polyunsaturated fatty acid and lectins in spleen interfere with each other or the expression of Ig production regulating activity.     

Role of calcium-binding sites in calcium-dependent membrane association of annexin A4

Annexin A4 (Anx4) is a cytosolic calcium-binding protein with four repeat domains, each containing one calcium-binding site (CBS). The protein interacts with the phospholipid membrane through the CBS-coordinated calcium ion, although the role of each CBS in the calcium-dependent association is unclear. To determine the role of each CBS, 15 CBS-abolished variants were produced in various combinations by substitution of a calcium-liganding residue on each CBS by Ala. Various mutant combinations produced different influences on calcium-dependent membrane-binding behavior and on the sodium-dependent dissociation of membrane-bound Anx4. Our data suggest the interaction of Anx4 with the lipid membrane consists of strong and weak interactions. CBSs I and IV mediate formation of strong interactions, while CBSs II and III are important for weak interactions. We also suggest Anx4 binds the lipid membrane through CBSs I and IV in the cytoplasmic fluids.     

Down-regulated miR-15a mediates the epithelial–mesenchymal transition in renal tubular epithelial cells promoted by high glucose

High glucose (HG) has been reported to be associated with renal dysfunction. And one potential mechanism underlining the dysfunction is the epithelial–mesenchymal transition (EMT) of renal tubular epithelial cells. Present study showed that EMT was induced in the HG-treated renal tubular epithelial cells by promoting the expression of mesenchymal phenotype molecules, such as α-SMA and collagen I, and down-regulating the expression of epithelial phenotype molecule E-cadherin. Moreover, we have identified the down-regulation of miR-15a which was accompanied with the HG-induced EMT. And the miR-15a overexpression inhibited the α-SMA, collagen I expression, and the promotion of E-cadherin expression by targeting and down-regulating AP4 which was also significantly promoted by the HG in the renal tubular epithelial cells. Thus, this study revealed that the weakening regulation on the AP4 expression by miR-15a might contribute to the HG-induced EMT in the renal tubular epithelial cells.     

Photosynthetic responses and acclimation of two castor bean cultivars to repeated drying–wetting cycles

To investigate the responses of castor bean to repeated drying–wetting cycles (RDWC), morpho-physiological parameters of two cultivars (Jiaxiang 2 and Hangbi 8) were determined by a pot experiment under well-watered control and RDWC. RDWC inhibited plant growth and leaf development, decreased water loss rate (WLR), and enhanced leaf mass per area (LMA) and chlorophyll content as indicated by spectral reflectance indices for both cultivars. Photosynthesis was inhibited by progressive drought stress but quickly recovered after rewatering for each cycle. Both cultivars exhibit a similar pattern of acclimation to RDWC: (1) higher LMA and lower WLR, (2) increased photosynthetic capacity under drought stress with increasing cycle numbers, (3) quick recovery and over-compensation for photosynthesis after rewatering, and (4) increased chlorophyll content. Jiaxiang 2 shows a high capacity for water preservation under drought stress and an over-compensation for photosynthesis after rewatering compared with Hangbi 8.     

On Cannabis indica,Indian hemp

Background: The South Aegean Volcanic Arc (SAVA), one of the most notable geological structures of the Mediterranean Sea, is floristically well known. Nevertheless, the factors that contribute to shaping the plant species richness of the SAVA remain unclear.

Aims: To investigate the factors that affect plant species richness and identify plant diversity hotspots in the SAVA and other central Aegean islands.

Methods: We used stepwise multiple regression to test the relationship between a number of environmental factors and plant species richness in the SAVA, as well as the residuals from the species–area linear regressions of native, Greek and Cycladian endemic taxa as indicators of relative species richness.

Results: The area was confirmed to be the most powerful single explanatory variable of island species richness, while geodiversity, maximum elevation and mean annual precipitation explained a large proportion of variance for almost all the species richness measures. Anafi, Amorgos and Folegandros were found to be endemic plant diversity hotspots.

Conclusions: We have demonstrated that geodiversity is an important factor in shaping plant species diversity in the Cyclades, while mean annual precipitation, human population density and maximum elevation were significant predictors of the Greek endemics present in the Cyclades. Finally, Anafi was found to be a plant diversity hotspot in the South Aegean Sea.     

The stable isotope ecology of terrestrial plant succession

We review the relevance and use of stable isotopes for the study of plant community succession. Stable isotope measurements provide information on the origin of resources acquired by plants, the processes governing resource uptake and transformation, and the physiological and environmental conditions of plant growth. When combined with measurements of the stable isotope ratio values of soil microbial biomass, soil organic matter and plant litter, isotope measurements of plants can indicate effects of successional changes on ecosystem processes. However, their application to questions of plant succession and ecosystem change is limited by the degree to which the underlying assumptions are met in each study, and complementary measures may be required, depending upon the question of interest. First, we discuss the changes that occur in the stable isotope composition of plants and ecosystems with ontogeny and species replacements, as well as their potential evolutionary significance. Second, we discuss the imprints of plant competition and facilitation on leaf and wood tissue, as well as how stable isotopes can provide novel insights on the mechanisms underlying plant interactions. Finally, we discuss the capacity for stable isotope measurements to serve as a proxy record for past disturbances such as fire, logging and cyclones.     

Transient spatio-temporal dynamics of a diffusive plant–herbivore system with Neumann boundary conditions

In many existing predator–prey or plant–herbivore models, the numerical response is assumed to be proportional to the functional response. In this paper, without such an assumption, we consider a diffusive plant–herbivore system with Neumann boundary conditions. Besides stability of spatially homogeneous steady states, we also derive conditions for the occurrence of Hopf bifurcation and steady-state bifurcation and provide geometrical methods to locate the bifurcation values. We numerically explore the complex transient spatio-temporal behaviours induced by these bifurcations. A large variety of different types of transient behaviours including oscillations in one or both of space and time are observed.     

Why is the world green? The interactions of top–down and bottom–up processes in terrestrial vegetation ecology

A classic question in plant ecology is “why is the world green?” That is, if plants are food for animals why do not animals eat all the available food – changing a ‘green world’ into a ‘brown world’. We first reviewed this question in 2009 and now revisit our arguments in the light of new data and new thinking. Here we argue that (1) the top–down bottom–up dichotomy is probably too simple for understanding a complex system – such as vegetation – rich in feedback processes. (2) Nevertheless it appears that bottom–up processes are generally more important for maintaining the presence of some sort of vegetation while top–down control process are generally more important in determining the type of vegetation at a site. (3) Although this review mainly takes a qualitative and experimental approach to the question, we also argue that simple well-known mathematical models from population ecology can be very informative in thinking about the types of explanations for the green world phenomenon, and demonstrating that it is rarely a simple choice between one form of control or another.     

Three new diterpenes with cytotoxic activity from the roots of Euphorbia ebracteolata Hayata

From the roots of Euphorbia ebracteolata Hayata, three new diterpenes, Ebracteolatas A–C, based on the rosane (1–2) and lathyrane (3) skeleton, were isolated together with four known ones (4–7). Their structures and relative configurations were elucidated on the basis of spectroscopic methods, especially 2D NMR techniques. Compounds 1, 6, and 7 exhibited moderate cytotoxic effects against five cancer cell lines.