Enhanced validation of small-molecule ligands and carbohydrates in the Protein Data Bank

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Value of heptyl-beta-D-thioglucoside, a new nonionic detergent, in studies on membrane proteins

A new nonionic detergent, heptylthioglucoside, was synthesized and found to be more soluble than octylthioglucoside in water at low temperatures. Use of this detergent for solubilization and reconstitution of membrane proteins of Escherichia coli was examined. Heptylthioglucoside was as effective as octylthioglucoside and octylglucoside in solubilizing membrane proteins, and by the heptylthioglucoside-dilution procedure the H+-translocating ATPase (F1F0) and melibiose carrier could easily be reconstituted into liposomes. It is concluded that heptylthioglucoside is very useful in studies on membrane proteins.     

Antioxidant properties of nitecapone (OR-462).

Nitecapone [3-(3,4-dihydroxy-5-nitrophenyl)methylene-2,4-pentanedione] [OR-462] is a catechol-O-methyltransferase inhibitor with gastroprotective properties. Recently, its antioxidant properties have been discovered: It scavenges peroxyl radicals (ROO.) and thus spares glutathione. Further examination of the properties of nitecapone demonstrated a remarkable ability of this compound to act as an antioxidant: (1) to scavenge ROO. in solution with a stoichiometry factor of 2; (2) to scavenge ROO. in membranes; (3) to inhibit lipid peroxidation; (4) to act as a competitive inhibitor for xanthine oxidase with Ki of 8.8 microM; (5) to scavenge O2- with a second order kinetic rate constant of 1.0 x 10(4) M-1 s-1; and (6) to scavenge HO.. Nitecapone also interacts with oxidation product of ascorbate to participate in recycling of vitamin E. Thus, nitecapone potentially is an effective therapeutic antioxidant, and the use of this compound in a combination with other antioxidants may be beneficial.     

Cytogenetics of a new type of barley with 16 chromosomes

In the progeny of a trisomic type for chromosome 6, Purple, a 16-chromosome type was obtained, which had a pair of new metacentric chromosome 6 in excess. The new metacentric chromosome 6 was shorter than any of the 14 chromosomes of normal barley complement and showed a heteropycnotic nature at late prophase in somatic mitosis. At metaphase I in the plants with 14+one metacentric chromosome 6 (2n=15) the chromosome configuration was exclusively 7_II+1_I indicating that the extra metacentric chromosome 6 could not associate with the normal chromosome 6. At diakinesis and metaphase I in the new 16-chromosome plants most of the sporocytes showed 8_IIor 7_II+2_I. Neither tetravalents nor trivalents were observed at meiosis. The chromosome behaviour at anaphase I and later stages of meiosis was regular in general, resulted in a fairly high pollen fertility of about 61 per cent. Seed fertility however, was very low. The transmission rate of the new metacentric chromosome 6 through the pollen was extremely low in 16-chromosome plants. Possible origin of new basic number and B-chromosome in diploid level through trisomic condition was suggested (Summary see p. 138).Contribution No. 141 of the Department of Plant Science, University of Manitoba.     

Effects of advance regeneration and germinated seedlings on forest recovery after clearcutting of Chamaecyparis obtusa plantations in Southern Kyushu,Southwestern Japan

We clarified the effect of advance regeneration on natural forest recovery after clearcutting of conifer plantations over the mid-term observation period (12–14 years to allow formation of the forest canopy). We established understory-intact plot (UI-plot), where advance regeneration (AR; DBH more than 1 cm before clearcutting) were retained, and understory-cleared plot (UC-plot), where all ARs were removed at felling of conifer crops. We surveyed individual density, species richness, and tree height with reference to different regeneration origins 1 year after and 12 or 14 years after clearcutting. Then, we compared the structural changes in UI-plot with that in UC-plot. The resprouted AR in UC-plot has provided the same effect as the retained AR in UI-plot in forming their height distribution patterns and stratification over a mid-term recovery process. We also found that individual density and species richness attributed by the individuals of newly established seedlings after clearcutting (SE), have contributed to the stand development in the both plots. Furthermore, SE was found to have a large contribution to forest recovery in terms of tree density and species number, while its significance for the recovery of gravity-dispersal, lucidophyllous trees was limited. We concluded that the advantage of AR retention is limited to the fast recovery of forest structure at the early stage after clearcutting, and mostly disappeared over a mid-term observation period as far as abundant advance regeneration was sufficiently accumulated and surrounding seed sources were effectively secured.

     

Single-Unit Imaging of Membrane Protein-Embedded Nanodiscs from Two Oriented Sides by High-Speed Atomic Force Microscopy

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A high-performance system of multiple gas-exchange chambers with a laser spectrometer to estimate leaf photosynthesis,stomatal conductance,and mesophyll conductance

Journal of Plant Research - Direct measurements of ecophysiological processes such as leaf photosynthesis are often hampered due to the excessive time required for gas-exchange measurements and the...