Root plasticity as the key root trait for adaptation to various intensities of drought stress in rice

Roots play an important role in rice adaptation to drought conditions. This study aimed to identify the key root traits that contribute to plant adaptation to drought stress. We used chromosome segment substitution lines (CSSLs) derived from Nipponbare and Kasalath crosses, which were grown in the field and hydroponics. In field experiments, the plants were grown under soil moisture gradients with line source sprinkler system up to around heading. Among the 54 CSSLs, only CSSL50 consistently showed significantly higher shoot dry matter production than its parent Nipponbare as the drought intensified for 3?years while most of the CSSLs reduced dry matter production to similar extents with Nipponbare under the same conditions. CSSL50 showed significantly greater total root length through promoted lateral root branching and elongation than Nipponbare, especially under mild stress conditions (15?30% w/w of soil moisture contents), which is considered as phenotypic plasticity. Such plastic root development was the key trait that effectively contributed to plant dry matter production through increased total root length and thus water uptake. However, there was no relationship between root plasticity and plant growth under the stress conditions induced by polyethylene glycol in hydroponics.     

Integrating Pathways of Parkinson's Disease in a Molecular Interaction Map

Parkinson's disease (PD) is a major neurodegenerative chronic disease, most likely caused by a complex interplay of genetic and environmental factors. Information on various aspects of PD pathogenesis is rapidly increasing and needs to be efficiently organized, so that the resulting data is available for exploration and analysis. Here we introduce a computationally tractable, comprehensive molecular interaction map of PD. This map integrates pathways implicated in PD pathogenesis such as synaptic and mitochondrial dysfunction, impaired protein degradation, alpha-synuclein pathobiology and neuroinflammation. We also present bioinformatics tools for the analysis, enrichment and annotation of the map, allowing the research community to open new avenues in PD research. The PD map is accessible at http://minerva.uni.lu/pd_map.     

Phylogenetic positions of RH blood group-related genes in cyclostomes

The RH gene family in vertebrates consists of four major genes (RH, RHAG, RHBG, and RHCG). They are thought to have emerged in the common ancestor of vertebrates after two rounds of whole genome duplication (2R-WGD). To analyze the detailed phylogenetic relationships within the RH gene family, we determined three types of cDNA sequence that belong to the RH gene family in lamprey (Lethenteron reissneri) and designated them as RHBG-like, RHCG-like1, and RHCG-like2. Phylogenetic analyses clearly showed that RHCG-like1 and RHCG-like2 genes, which were probably duplicated in the lamprey lineage, are orthologs of gnathostome RHCG. In contrast, the clear phylogenetic position of the RHBG-like gene could not be obtained. Probably some convergent events for cyclostome RHBG-like genes prevented the accurate identification of their phylogenetic positions.     

Stable carbon isotope variability associated with taxonomic composition of lotic benthic algae

We examined the relationship between the δ¹³C and taxonomic composition of benthic algae collected from a riffle (fast current habitat) of a non‐shaded mountain stream, which is a tributary of the Kiso River, Japan. The benthic algal δ¹³C ranged from ?20.6 to ?14.2‰ and tended to be ¹³C‐depleted with increasing relative abundance of upright filamentous cyanobacteria and ¹³C‐enriched with increasing relative abundance of prostrate filamentous cyanobacteria. Using isotopic mass balance equations, the relative abundance of the dominant taxa, upright and prostrate filamentous cyanobacteria, small diatoms and others, explained 74% of δ¹³C variability. This study shows a case where the difference in taxonomic composition is a possible source of the isotopic variability of benthic algae, which is a mixture of taxa with distinct isotopic signatures.     

Synthetic Studies on 2′-Substituted-4′-thiocytidine Derivatives as Antineoplastic Agents

Abstract

As potential antineoplastic agents, we have synthesized 4′-thioFAC and 4′-thiocytarazid by developing an alternative synthetic method. 4′-ThioFAC showed potent antineoplastic activities in vivo as well as in vitro.     

The nucleotide binding site of F1-ATPase which carries out uni-site catalysis is one of the alternating active sites of the enzyme

Nucleotide-depleted mitochondrial F1-ATPase binds 3'-(2')-O-(2-nitro-4-azidobenzoyl)-derivatives of ATP (NAB-ATP) and GTP (NAB-GTP) when these nucleotide analogues are added to the enzyme in equimolar quantities in the presence of Mg2+ (uni-site catalysis conditions). The binding of NAB-ATP is accompanied by its hydrolysis and inorganic phosphate dissociation from the enzyme; NAB-ADP remains bound to F1-ATPase. The F1-ATPase X NAB-ADP complex has no ATPase activity and its reactivation in the presence of an excess of ATP is accompanied by NAB-ADP release. The illumination of the F1-ATPase complexes with NAB-ADP or NAB-GDP leads to the covalent binding of one nucleotide analogue molecule to the enzyme and to the irreversible inactivation of F1-ATPase. It follows from the results obtained that the modification of just one of the F1-ATPase catalytic sites is sufficient to complete the inhibition of ATPase activity.     

Dynamic behavior of the imino protons of the gamma OR3 17mer in H2O solution studied by high-resolution NMR

The imino proton resonances of gamma OR3 17mer in water were observed at 500 MHz with the time-shared Redfield pulse train. All of the 17 imino proton resonances could be assigned specifically to individual base pairs by utilizing the trace of NOE connectivities between the imino and adenine C2H protons and between imino protons themselves. AT1 and 17 showed abnormally high chemical shifts in comparison with the other AT pairs. On raising the temperature, broadening of the signal occurred in a sequential manner from the terminals except for AT10 and AT11, which were broadened at a lower temperature than GC12. The relaxation rates of the imino protons were measured by the inversion recovery method. The rates at higher temperatures represent the exchange rates of the imino protons. From the temperature dependences, activation energies of about 15 kcal/mol for the AT imino protons and 23-26 kcal/mol for the GC imino protons were obtained.     

Nicorandil is a potent dilator of endothelin-induced vascular contraction

Nicorandil, an antianginal drug, is known to open K+ channel and to increase cGMP production. The effects of nicorandil on vascular contraction induced by endothelin (ET), a potent newly discovered vasoconstrictor peptide, were investigated using helical strips from rat thoracic aorta. ET at a concentration of 5 x 10(-9) M induced strong and persistent contraction in the presence of extracellular Ca2+ and similar persistent but smaller contraction in the absence of extracellular Ca2+. Nicorandil at concentrations greater than 10(-7) M, strongly and dose-dependently inhibited ET-induced contraction in the presence of extracellular Ca2+. Nicorandil also suppressed ET-induced contraction in the presence of 10(-4) M methylene blue, an inhibitor of cGMP production, in the presence of extracellular Ca2+ but not in the absence of extracellular Ca2+. ET-induced contraction was also inhibited to lesser extents by the Ca2+ channel blockers nicardipine and verapamil. Nicorandil also strongly suppressed ET-induced increase in cytosolic free Ca2+ concentration in cultured vascular smooth muscle cells. These results suggest that nicorandil is a potent dilator of ET-induced vasoconstriction.     

Biosynthesis of Poly(3-Hydroxyalkanoic Acid) Copolymer from CO(inf2) in Pseudomonas acidophila through Introduction of the DNA Fragment Responsible for Chemolithoautotrophic Growth of Alcaligenes hydrogenophilus

Pseudomonas acidophila is a bacterial strain producing a poly(3-hydroxyalkanoic acid) (PHA) copolymer from low-molecular-weight organic compounds such as formate and acetate. The genes responsible for PHA production were cloned in cosmid pIK7 containing a 14.8-kb HindIII fragment of P. acidophila DNA. With the aim of developing a means of producing a PHA copolymer from CO(inf2), cosmid pIK7 was introduced into a polymer-negative mutant of the chemolithoautotrophic bacterium Alcaligenes eutrophus PHB(sup-)4. However, the recombinant strain produced a homopolymer of 3-hydroxybutyric acid (polyhydroxybutyric acid) from CO(inf2). Since it was thought that the composition of the accumulated polymer might depend not on the PHA biosynthetic genes but on the metabolism of the host strain, a recombinant plasmid, pFUS, containing the genes for chemolithoautotrophic growth of the hydrogen-oxidizing bacterium A. hydrogenophilus was introduced into P. acidophila by conjugation. The recombinant plasmid pFUS was stably maintained in P. acidophila in the absence of chemolithoautotrophic or antibiotic selection. This pFUS-harboring strain possessed the ability to grow under a gas mixture of H(inf2), O(inf2), and CO(inf2) in a mineral salts medium, and PHA copolymer accumulation was confirmed by nuclear magnetic resonance spectral analysis. A gas chromatogram obtained by gas chromatography-mass spectrometry showed the composition of the polymer to be 52.8% 3-hydroxybutyrate, 41.1% 3-hydroxyoctanoate, and 6.1% 3-hydroxydecanoate. This is the first report of the production of a PHA copolymer from CO(inf2) as sole carbon source.     

Phenotypic diversity of 188 rice embryo mutants

We have identified 188 embryo mutants of rice and characterized them into six groups based on their phenotypes: (1) embryoless in mature seed, (2) deletion of embryonic organ(s), (3) abnormal position of embryonic organs, (4) abnormal embryo size, (5) defect in organ morphology, and (6) variable abnormal phenotypes in spite of single mutations. Three types of organless mutants are obtained: small globular embryo, club-shaped embryo, and large embryo. Although 12 shootless mutants derived from at least three loci are identified, only three radicleless mutants are recovered, which produce normal adventitious roots after germination. In reduced embryo mutants, every embryonic organ is reduced, in contrast to giant embryo mutants in which only scutellum is enlarged. Considerable number of mutants are categorized into (5) and (6) in the above. These diverse embryo mutants would serve as promising materials for genetic study of embryogenesis. © 1995 Wiley-Liss, Inc.