Tertiary structure of plant RuBisCO: domains and their contacts

The three-dimensional structure of ribulose-1,5-biphosphate carboxylase-oxygenase (RuBisCO), has been determined at 2.6 A resolution. This enzyme initiates photosynthesis by combining carbon dioxide with ribulose bisphosphate to form two molecules of 3-phosphoglycerate. In plants, RuBisCO is built from eight large (L) and eight small (S) polypeptide chains, or subunits. Both S chains and the NH2-terminal domain (N) of L are antiparallel beta, "open-face-sandwich" domains with four-stranded beta sheets and flanking alpha helices. The main domain (B) of L is an alpha/beta barrel containing most of the catalytic residues. The active site is in a pocket at the opening of the barrel that is partly covered by the N domain of a neighboring L chain. The domain contacts of the molecule and its conserved residues are discussed in terms of this structure.     

Use of grain-size and elemental normalization in the interpretation of trace metal concentrations in soils of the reclaimed area adjoining Port Jackson, Sydney, Australia

Cobalt, Cr, Cu, Fe, Mn, Ni, Pb, Zn and As concentrations in the grain size and elemental normalization using Fe in gravel-free total soil ((X_m/Fe)_{total sample}; X_m = Cu, Pb, Zn, etc.) were used to determine the influence of variable grain size on the concentration of anthropogenic trace metal contaminants in the reclaimed area adjacent to Port Jackson, Sydney, Australia. Trace metal concentrations in soils in reclaimed area are greatly influenced by the heterogeneous nature of the waste materials buried at the site. The confounding effects of variable grain size in soils can be reduced by analyzing the contaminant concentration of the material after removing > 2 mm size in sample. An example from Sydney Harbour is used to demonstrate the comparability between grain size normalized data and elemental normalized data using Fe in soils from reclaimed areas. Results from the current study reveal that the vertical distribution of trace metal concentrations in soils is remarkably similar between the grain size and elemental normalization, using Fe. Normalization methods might be beneficial in overcoming texturally driven variations of contaminant concentrations in soils in the reclaimed or infilled land area.     

Identification of QTLs for domestication-related and agronomic traits in an Oryza sativa×O. rufipogon BC1F7 population

Asian cultivated rice was domesticated from the wild rice, Oryza rufipogon and throughout the domestication process, a wide range of morphological and physiological changes altered the ancestral form. This study was conducted to identify the genetic basis of changes associated with the domestication process. An recombinant Inbred line (RIL) population consisting of 120 lines was developed from a cross between the Juponica cultivar.‘Hwayeongbyeo’and a presumed wild progenitor. O. rufipogon Griff. Acc.01944. The population was genotyped with 124 simple sequence length repeat (SSR) markers, providing an average interval size of 15 cM, and also evaluated for 20 traits related to domestication and agricultural performance. A total of 63 quantitative trait locus (QTLs) and one locus associated with qualitative variation for pericarp coloration were identified using single point and composite interval analysis. The number of QTLs per trait ranged from one to seven. Phenotypic variation associated with each QTL ranged from 3.7 to 40.4%. with an average of 15.3%. The results indicated that most domestication‐related traits clustered in chromosomal blocks, and the positions of many of these clusters were consistent with those reported in previous studies and with skewed segregation ratios in these BC₁,F₇ RILs. For 13 (20.6%) of the QTLs identified in this study. the O. rufipogan ‐derived allele contributed a desirable agronomic effect despite the overall undesirable characteristics of the wild phenotype. Favourable alleles from O. rufipogan were detected for panicle length, spikelets per panicle, days to heading and leaf discoloration associated with cold stress. When compared with previous studies involving interspecific crosses, it can be concluded that O. rufipogon is useful as a source of valuable alleles for rice improvement and that many of the introgressed regions contain genes that have a favourable impact on phenotype in different genetic backgrounds and different environments.     

Identification and evaluation of <Emphasis Type="Italic">Forsythia</Emphasis> germplasm using molecular markers

This study identifies Forsythia germplasm and evaluated the genetic relationships of F. ×intermedia hybrids, cultivars and their putative parental species. Leaf samples of F. ×intermedia cultivars and species, such as F. koreana and F. suspensa, were collected in the Netherlands, Korea, and USA. Total genomic DNA was extracted and evaluated by randomly amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) analyses. Dendrograms were constructed by using the neighbor-joining (NJ) clustering algorithm applying the interior branch (IB) test or analyzed by STRUCTURE. In the dendrogram generated by RAPD markers, two major clusters were observed. One cluster (CL-I) contained most of the F. ×intermedia cultivars, F. suspensa, and F. koreana. The other cluster (CL-II) included F. europaea, F. ovata, F. densiflora, F. mandshurica, F. japonica, F. viridissima, and cultivars derived from F. ovata. In the AFLP dendrogram, the placement of F. ×intermedia cultivars with F. suspensa was similar, forming cluster CL-A I. The RAPD and AFLP results clearly separated most F. ×intermedia cultivars from F. ovata derived cultivars. The full range of genetic diversity of F. suspensa and F. viridissima should be investigated to verify whether these two species are truly parental taxa for F. ×intermedia. Placement of F. viridissima, F. ovata, and F. japonica in different sub-clusters requires further investigation regarding genetic diversity in the species, and their close relationship with F. koreana, F. mandshurica, and F. saxatalis.     

Protective Effects of Platycodon grandiflorum Aqueous Extract on Thioacetamide-induced Fulminant Hepatic Failure in Mice

The aim of the present study was to evaluate the protective activity of aqueous extract from Platycodon grandiflorum (BC703) on thioacetamide (TA)-induced hepatotoxicity in mice. We found that BC703 significantly decreased mortality and the change in serum transaminase following TA administration. The group treated with BC703 at doses of 1, 5, and 10 mg/kg produced significant hepatoprotective effects against TA-induced liver damage by decreasing the activities of serum enzymes, nitric oxide and lipid peroxidation in dose-dependent manners. Histopathological studies further substantiated the protective effect of BC703. These results show the hepatoprotective activity of aqueous extract from Platycodon grandiflorum on thioacetamide-induced fulminant hepatic failure.     

Minimum anesthetic concentration and cardiovascular dose-response relationship of isoflurane in cinereous vultures (Aegypius monachus)

This study aimed to determine the minimum anesthetic concentration (MAC) and dose-related cardiovascular effects of isoflurane during controlled ventilation in cinereous vultures (Aegypius monachus). The MAC was determined for 10 cinereous vultures as the midpoint between the end-tidal isoflurane concentration that allows gross purposeful movement and that which prevents the movement in response to clamping a pedal digit. Immediately after the MAC was determined, the cardiovascular effects of isoflurane at 1.0, 1.5, and 2.0 times the MAC were investigated in seven of the 10 birds. The MAC of isoflurane for 10 cinereous vultures during controlled ventilation was 1.06 +/- 0.07% (mean +/- SD). When the isoflurane concentration was increased to 1.5 and 2.0 times the MAC, there was significant dose-dependent decrease in the arterial blood pressure. However, the heart rate did not change over a range of 1.0 to 2.0 times the MAC.     

In vivo metabolism of Talosin A, new isoflavonol glycoside from Kitasatospora kifunensis, in rats

The isoflavonol glycoside Talosin A, genistein (GT)-7-α-L-6-deoxy talopyranose (GT-Tal), was first isolated from the culture broth of Kitasatospora kifunensis MJM341. The aim of the present study was to evaluate the oral absorption and metabolism of the newly isolated isoflavonol glycoside, GT-Tal compared to genistin (GT-7-O-β-D-glucopyranoside; GT-Glu). Free GT-Glu and GT-Tal could not be detected prior to enzymatic hydrolysis of the corresponding conjugates in rat plasma. Following oral administration of GT-Tal (15 min), GT-Tal was rapidly absorbed through the gastrointestinal tract and metabolized into GT-Tal conjugates with a mean C_max of 2.74 µg/mL. GT-Tal was further metabolized to its aglycone, free GT and conjugated GT. After oral administration, GT-Glu was absorbed after being convereted to its aglycone and then further metabolized into its conjugate metabolites (free GT with a mean C_max of 0.24 mg/mL at 1.25 h; conjugated GT with a mean C_max of 1.31 mg/mL at 2.00 h). Significant differences in absorption and metabolism of GT-Tal and GT-Glu were observed. GT-Tal was metabolized into its corresponding conjugates or underwent deglycosylation to form GT, whereas GT-Glu was metabolized into its aglycone, GT.