Dynamics of heterorhizic root systems: protoxylem groups within the fine-root system of Chamaecyparis obtusa

To understand the physiology of fine-root functions in relation to soil organic sources, the heterogeneity of individual root functions within a fine-root system requires investigation. Here the heterogeneous dynamics within fine-root systems are reported. The fine roots of Chamaecyparis obtusa were sampled using a sequential ingrowth core method over 2 yr. After color categorization, roots were classified into protoxylem groups from anatomical observations. The root lengths with diarch and triarch groups fluctuated seasonally, whereas the tetrarch root length increased. The percentage of secondary root mortality to total mortality increased with increasing amounts of protoxylem. The carbon : nitrogen ratio indicated that the decomposability of primary roots might be greater than that of secondary roots. The position of diarch roots was mostly apical, whereas tetrarch roots tended to be distributed in basal positions within the root architecture. We demonstrate the heterogeneous dynamics within a fine-root system of C. obtusa. Fine-root heterogeneity should affect soil C dynamics. This heterogeneity is determined by the branching position within the root architecture.     

Kinetic mechanism of pulmonary carbonyl reductase.

An IgG1 monoclonal antibody, Sulph I, reacting with sulphatide (3'-sulphogalactosylceramide), was produced by immunizing Balb/c mice with that glycolipid coated on Salmonella minnesota bacterial membrane. Radioimmunodetection of the binding of the monoclonal antibody to structurally related glycolipids adsorbed to microtitre plates or chromatographed on thin-layer plates was used to determine its binding epitope. The antibody showed similar binding avidity to three sulphated glycolipids: sulphatide, sulpholactosylceramide and seminolipid. Lysosulphatide did bind the antibody, but, compared with sulphatide, 30 times more antigen was needed for half-maximal binding. Bis(sulphogangliotriosyl)ceramide and bis-sulphogangliotetraosylceramide did not bind the antibody. These results suggest that terminal galactose-3-O-sulphate and part of the hydrophobic region of the glycolipid are recognized by the Sulph I antibody.     

Evidence of intracellular and trans-acting differentiation-inducing activity in human promyelocytic leukemia HL-60 cells: its possible involvement in process of cell differentiation from a commitment step to a phenotype-expression step

We previously reported that human promyelocytic leukemia HL-60 cells, when treated with various inducers in magnesium-deficient medium, became committed to differentiate but did not express the differentiation-related phenotypes (Okazaki et al., J. Cell. Physiol., 131:50-57, 1987). In the present study we demonstrated the existence of an intracellular differentiation-inducing activity (int-DIA) in differentiation-committed phenotype-nonexpressing HL-60 cells by using cybrid formation between untreated HL-60 cells and cytoplasts from HL-60 cells treated in magnesium-deficient medium with 100 nM 1 alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3). Cell extracts from similarly treated HL-60 cells also showed int-DIA, which when added (10 mg total protein/ml) to culture of untreated HL-60 cells, could increase the percentages of nitroblue tetrazolium (NBT)- and nonspecific esterase (NSE)-positive cells from 1% to 53%, and from 0 to 32%, respectively. They also induced differentiation of human monoblastic leukemia U-937 cells and of human myeloblastic leukemia KG-1 cells but not of erythroleukemia K-562 cells. These results suggested that the int-DIA had a common effect on differentiation induction in several human myeloid cell lines and may be involved in inducing cells to proceed from a commitment to a phenotype-expression step during human myeloid cell differentiation.     

TPA-induced multinucleation of a mesenchymal stem cell-like clone is mediated primarily by karyokinesis without cytokinesis, although cell-cell fusion also occurs

The 5F9A cell, which is a mesenchymal stem cell-like clone established from rat bone marrow substrate adherent cells, can differentiate into adipocytes and osteoblasts in vitro under the appropriate conditions. Multinucleated cells could be also induced by 12-O-tetradecanoylphorbol 13-acetate (TPA) in 5F9A cells. This effect was mediated by protein kinase C. Possible mechanisms of multinucleation by TPA were hypothesized to be either karyokinesis without cytokinesis or cell-cell fusion. By observation using time-lapse phase-contrast microscopy, we determined that the multinucleated cells were generated mainly by karyokinesis without cytokinesis. Cell fusion was studied using time-lapse photography, and confocal laser scanning microscopy using two differentially labeled cells. These techniques demonstrated that multinucleated 5F9A cells could be produced by cell fusion, albeit at a low frequency. We conclude that multinucleated 5F9A cells are formed primarily by karyokinesis without cytokinesis, although some cells are also formed by cell-cell fusion.     

Comparative study of the sugar chains of factor VIII purified from human plasma and from the culture media of recombinant baby hamster kidney cells.

The asparagine-linked sugar chains of blood coagulation factor VIII preparations purified from human plasma of blood group A donors and from the culture media of recombinant BHK cells were released as oligosaccharides by hydrazinolysis. These sugar chains were converted to radioactive oligosaccharides by reduction with sodium borotritide and separated into neutral and acidic fractions by paper electrophoresis. Most of the acidic oligosaccharides were converted to neutral ones by sialidase digestion, indicating that they are sialyl derivatives. The neutral and sialidase-treated acidic oligosaccharides were fractionated by serial chromatography on immobilized lectin columns and Bio-Gel P-4 column. Structural study of each oligosaccharide by sequential exo- and endoglycosidase digestion and by methylation analysis revealed that both factor VIII preparations contain mainly high mannose-type and bi-, tri-, and tetra-antennary complex-type sugar chains. Some of the biantennary complex-type sugar chains from human plasma factor VIII contain blood group A and/or H determinant, while those from recombinant product do not. Some of the bi-, tri- and tetra-antennary complex-type sugar chains of the recombinant factor VIII contain the Gal alpha 1----3Gal group. A small number of the triantennary complex-type sugar chains from both preparations was found to contain the Gal beta 1----4(Fuc alpha 1----3)GlcNAc beta 1----4 (Gal beta 1----4GlcNAc beta 1----2)Man group. Studies of pharmacokinetic parameters of the recombinant factor VIII infused into baboons revealed that its half-life in blood circulation is similar to that of plasma derived factor VIII, suggesting that the oligosaccharide structural differences between them do not affect the fate of factor VIII in vivo.     

Earliest colobine skeletons from Nakali,Kenya

Old World monkeys represent one of the most successful adaptive radiations of modern primates, but a sparse fossil record has limited our knowledge about the early evolution of this clade. We report the discovery of two partial skeletons of an early colobine monkey (Microcolobus) from the Nakali Formation (9.8–9.9 Ma) in Kenya that share postcranial synapomorphies with extant colobines in relation to arboreality such as mediolaterally wide distal humeral joint, globular humeral capitulum, distinctly angled zona conoidea, reduced medial trochlear keel, long medial epicondyle with weak retroflexion, narrow and tall olecranon, posteriorly dislocated fovea on the radial head, low projection of the femoral greater trochanter, wide talar head with a greater rotation, and proximodistally short cuboid and ectocuneiform. Microcolobus in Nakali clearly differs from the stem cercopithecoid Victoriapithecus regarding these features, as Victoriapithecus is postcranially similar to extant small‐sized terrestrial cercopithecines. However, degeneration of the thumb, a hallmark of modern colobines, is not observed, suggesting that this was a late event in colobine evolution. This discovery contradicts the prevailing hypothesis that the forest invasion by cercopithecids first occurred in the Plio‐Pleistocene, and shows that this event occurred by the late Miocene at a time when ape diversity declined. Am J Phys Anthropol 143:365‐382, 2010. © 2010 Wiley‐Liss, Inc.     

Fluorescent rotors and their applications to the study of G-F transformation of actin.

New fluorescent rotor molecules having hydrophilic functional groups, which are derivatives of p-(N,N-dialkylamino)benzylidenemalononitrile, were synthesized. Their properties as fluorescent rotors were confirmed by an observation of solvent viscosity-dependent fluorescence. Incorporation of hydrophilic groups into the molecules increased the solubility of fluorescent rotors in aqueous media; the application of the compounds to biochemical systems became feasible as a consequence. To demonstrate this applicability, we attempted to monitor the G-F transformation of rabbit skeletal muscle actin with these newly synthesized compounds. All the compounds carrying a malononitrile moiety showed greater fluorescence in F-actin. Among them, 1-(2-hydroxyethyl)-6-[(2,2-dicyano)vinyl]-2,3,4-trihydroquinoli ne gave the best result by the criteria of the difference in fluorescence quantum yield for G- and F-actin, solubility, and stability of the compound. The method has the major advantage of not requiring covalent modification of actin.     

Why does avian influenza A virus hemagglutinin bind to avian receptor stronger than to human receptor? Ab initio fragment molecular orbital studies

Influenza A viruses attach to alpha-sialosides on the target cell surface by their hemagglutinins, which strictly recognize the difference in sialic acid-galactose linkage. Why does avian virus H3 subtype bind to avian receptor Neu5Ac(alpha2-3)Gal stronger than to human receptor Neu5Ac(alpha2-6)Gal? Why does avian H3 mutated Gln226 to Leu preferentially bind to human receptor? In this paper, we theoretically answer the questions by molecular mechanics and ab initio fragment molecular orbital (FMO) calculations. The binding energy between avian H3 and avian receptor is 8.2kcal/mol larger than that of the avian H3-human receptor complex estimated at the FMO-HF/STO-3G level, which is a reason that avian H3 binds to avian receptor stronger than to human receptor. Avian Leu226 H3 clashes to Gal unit on the avian receptor to quite decrease its binding affinity. In contrast, Gal unit on the human receptor forms intermolecular hydrophobic interaction with avian Leu226 H3 to afford moderate binding affinity.     

Properties of cytosolic components activating rat hepatic 5'' [corrected]-deiodination in the presence of NADPH.

The effects of cytosol, NADPH and reduced glutathione (GSH) on the activity of 5'-deiodinase were studied by using washed hepatic microsomes from normal fed rats. Cytosol alone had little stimulatory effect on the activation of microsomal 5'-deiodinase. NADPH had no stimulatory effect on the microsomal 5'-deiodinase unless cytosol was added. 5'-deiodinase activity was greatly enhanced by the simultaneous addition of NADPH and cytosol (P less than 0.001); this was significantly higher than that with either NADPH or cytosol alone (P less than 0.001). GSH was active in stimulating the enzyme activity in the absence of cytosol, but the activity of 5'-deiodinase with 62 microM-NADPH in the presence of cytosol was significantly higher than that with 250 microM-GSH in the presence of the same concentration of cytosol (P less than 0.001). The properties of the cytosolic components essential for the NADPH-dependent activation of microsomal 5'-deiodinase independent of a glutathione/glutathione reductase system were further assessed using Sephadex G-50 column chromatography to yield three cytosolic fractions (A, B and C), wherein A represents pooled fractions near the void volume, B pooled fractions of intermediate Mr (approx. 13 000), and C of low Mr (approx. 300) containing glutathione. In the presence of NADPH (1 mM), the 5'-deiodination rate by hepatic washed microsomes is greatly increased if both A and B are added and is a function of the concentrations of A, B, washed microsomes and NADPH. A is heat-labile, whereas B is heat-stable and non-dialysable. These observations provide the first evidence of an NADPH-dependent cytosolic reductase system not involving glutathione which stimulates microsomal 5'-deiodinase of normal rat liver. The present data are consistent with a deiodination mechanism involving mediation by a reductase (other than glutathione reductase) in fraction A of an NADPH-dependent reduction of a hydrogen acceptor in fraction B, followed by reduction of oxidized microsomal deiodinase by the reduced acceptor (component in fraction B).