Effects of understory dwarf bamboo on soil water and the growth of overstory trees in a dense secondary Betula ermanii forest, northern Japan

The original publication is available at www.springerlink.comArticleECOLOGICAL RESEARCH. 18(6):767-774(2003)journal articl

Memet Fuat, Piraye ve Nazım

Taha Toros Arşivi, Dosya Adı: Nazım Hikmetİstanbul Kalkınma Ajansı (TR10/14/YEN/0033) İstanbul Development Agency (TR10/14/YEN/0033

The effect of population density on shoot morphology of herbs in relation to light capture by leaves

Plants change their shapes, depending on their environment, for example, plant height increases with increasing population density. We examined the density-dependent plasticity in shoot morphology of herbs by analysing a mathematical model which identifies a number of key factors that influence shoot morphology, namely (i) solar radiation captured by leaves; (ii) shading from neighbouring plants; and (iii) utilisation efficiency of resource by leaves, stems and veins. An optimisation theory was used to obtain optimal shoot morphology in relation to maximal light capture by leaves, under trade-offs of resource partition among organs. We first evaluated the solar radiation flux per unit leaf area per day for different shoot forms. Our model predicts that the optimal internodal length of the stem that brings about the maximal light capture by leaves increases with plant population density, and this is consistent with experimental data. Moreover, our simple model can also be extended to explain the morphological plasticity in other herbs (i.e. stemless plants) that are different from our model plants with a stem. These findings illustrate how optimisation theory can be used for the analysis of plasticity in shoot morphology of plants in response to environmental changes, as well as the analysis of diversity in morphology

Improvement in sulfur desorption of NOX storage and reduction catalysts using a Ba–Ti composite oxide

A Ba-Ti composite oxide was formed on a NOx storage and reduction catalyst via impregnation of a Ba-Ti precursor solution composed of H(2)O(2) added to a complex prepared using the citric acid method. The structure of the Ba-Ti composite in solution was analyzed by chemical composition analysis and FT-Raman and UV-vis spectroscopy. MM2 calculations were performed to propose its chemical structure. Both Ba and Ti together were found to form a composite molecule in the solution. Furthermore, TEM-EDX and XRD analyses of the Ba-Ti composite oxide on the catalyst prepared by impregnation with the Ba-Ti composite aqueous solution revealed that Ba and Ti in the catalyst were highly dispersed at the nm scale. The formation of the Ba-Ti composite oxide on the NSR catalyst enhanced sulfur desorption efficiency and led to high-performance NO(X) conversion as a NO(X) storage and reduction activity catalyst after desulfation treatment. It was assumed that the existence of nano-scaled Ba compounds combined with Ti was efficient for the inhibition of the sintering of barium sulfate and its facile decomposition. It was found that dispersion of Ba compounds for NO(X) storage materials using a Ba-Ti complex solution is an efficient way to improve the durability of NSR catalysts

The Escherichia coli K-12 ORFeome: a resource for comparative molecular microbiology

<p>Abstract</p> <p>Background</p> <p>Systems biology and functional genomics require genome-wide datasets and resources. Complete sets of cloned open reading frames (ORFs) have been made for about a dozen bacterial species and allow researchers to express and study complete proteomes in a high-throughput fashion.</p> <p>Results</p> <p>We have constructed an open reading frame (ORFeome) collection of 3974 or 94% of the known <it>Escherichia coli </it>K-12 ORFs in Gateway^®entry vector pENTR/Zeo. The collection has been used for protein expression and protein interaction studies. For example, we have compared interactions among YgjD, YjeE and YeaZ proteins in <it>E. coli</it>, <it>Streptococcus pneumoniae</it>, and <it>Staphylococcus aureus</it>. We also compare this ORFeome with other Gateway-compatible bacterial ORFeomes and show its utility for comparative functional genomics.</p> <p>Conclusions</p> <p>The <it>E. coli </it>ORFeome provides a useful resource for functional genomics and other areas of protein research in a highly flexible format. Our comparison with other ORFeomes makes comparative analyses straighforward and facilitates direct comparisons of many proteins across many genomes.</p

Nap1 regulates proper CENP-B binding to nucleosomes

CENP-B is a widely conserved centromeric satellite DNA-binding protein, which specifically binds to a 17-bp DNA sequence known as the CENP-B box. CENP-B functions positively in the de novo assembly of centromeric nucleosomes, containing the centromere-specific histone H3 variant, CENP-A. At the same time, CENP-B also prevents undesired assembly of the CENP-A nucleosome through heterochromatin formation on satellite DNA integrated into ectopic sites. Therefore, improper CENP-B binding to chromosomes could be harmful. However, no CENP-B eviction mechanism has yet been reported. In the present study, we found that human Nap1, an acidic histone chaperone, inhibited the non-specific binding of CENP-B to nucleosomes and apparently stimulated CENP-B binding to its cognate CENP-B box DNA in nucleosomes. In human cells, the CENP-B eviction activity of Nap1 was confirmed in model experiments, in which the CENP-B binding to a human artificial chromosome or an ectopic chromosome locus bearing CENP-B boxes was significantly decreased when Nap1 was tethered near the CENP-B box sequence. In contrast, another acidic histone chaperone, sNASP, did not promote CENP-B eviction in vitro and in vivo and did not stimulate specific CENP-B binding to CENP-A nucleosomes in vitro. We therefore propose a novel mechanism of CENP-B regulation by Nap1

STRUCTURE AND SUCCESSION OF ALPINE PERENNIAL COMMUNITY (POLYGONUM CUSPIDATUM) ON MT. FUJI (Twelfth Symposium on Polar Biology)

Successional process of herbaceous perennial was investigated on the alpine zone of Mt. Fuji. The study site is located at the timberline of the southeast slope where it is mainly covered by various growing types of Polygonum cuspidatum patch. The structure of these patches was studied in relation to the successional stage of the alpine timberline. Measurements of shoot height, density of shoots, biomass above the ground and soil nutrient condition were carried out in patches of various sizes. The biomass of large, medium and small patches was 3400, 970 and 120g, respectively. In the central part of the large patch, a low density and low biomass area (dead center) existed, and where other species have invaded. These various-sized patches play a significant role in the successional process on the alpine zone